Improved acyltransfe se polynucleotides, polypeptides, and methods of use
TECHNICAL FIELD
The invention relates to compositions and methods for the manipulation of cellular lipid
production and/ or cellular lipid profile.
BACKGROUND
Plant oil is an economically important product not only due to its broad utilization in the food
industry and as a component of feed ingredients but it also has a wide range of applications as
bio fuels or in the manufacture of various nutraceutical and industrial products. Within the plant
itself, oil is essential to carry out a number of metabolic processes which are vital to growth and
development particularly during seed germination and early plant growth stages. Considering its
value, there is a growing research interest within the biotechnology field to improve plant oil
production and make the supply more sustainable.
The major component of plant oil is triacylglyceride (TAG). It is the main form of storage lipid
in oil seeds and the primary source of energy for seed germination and seedling development.
TAG biosynthesis via the Kennedy pathway involves sequential acylation steps starting from the
precursor -glycerol-3-phosphate (G3P). Firstly, G3P is esterified by an acyl-CoA to form
. phosphatidic acid (LPA) in a reaction catalyzed by glycerol-3-phosphate acyltransferase
(GPAT, EC 2.3.1.15). This is followed by a second acylation step catalyzed by . phosphatidic
acid acyltransferase (LPAT; EC 2.3.1.51) forming phosphatidic acid (PA), a key intermediate in
the biosynthesis of glycerolipids. The PA is then dephosphorylated by the enzyme phosphatidic
acid phosphatase (PAP; EC3. 1.3.4) to release the immediate precursor for TAG, the sn- 1,2-
diacylglycerol (DAG). Finally, DAG is acylated in the sn-3 position by the enzyme diacylglycerol
acyltransferase (DGAT; EC 2.3.1.20) to form TAG.
Since this last catalytic action is the only unique step in TAG biosynthesis, DGAT is termed as
the committed triacylglycerol-forming enzyme. As DAG is located at the branch point between
TAG and membrane phospholipid biosyntheses, DGAT potentially plays a decisive role in
regulating the formation of TAG in the glycerolipid synthesis pathway (Lung and Weselake,
2006, Lipids. Dec 2006;41 (12): 1073-88). There are two different families of DGAT proteins.
The first family of DGAT proteins ("DGAT1") is related to the acyl-coenzyme Axholesterol
acyltransferase ("ACAT") and has been desbried in the U.A. at. 6,100,077 and 6,344,548. A
second family of DGAT proteins ("DGAT2") is unrelated to the DGAT1 family and is
described in PCT Patention PubUcation WO 2004/01 1671 published Feb. 5, 2004. Other
references to DGAT genes and their use in plants include PCT Publication Nos.
WO2004/01 1,671, WO1998/055,631, and WO2000/001,71 3, and US Patent PubUcation No.
200301 15632.
DGAT1 is typicaUy the major TAG synthesising enzyme in both the seed and senescing leaf
(Kaup et a/, 2002, Plant Physiol. 129(4):1 616-26; for reviews see Lung and Weselake 2006,
Lipids. 4 1(12):1073-88; Cahoon et a/., 2007, Current Opinion in Plant Biology. 10:236-244; and Li
et a/., 2010, Lipids. 45:145-1 57).
Raising the yield of oilseed crops (canola, sunflower, safflower, soybean, corn, cotton, Unseed,
flax etc) has been a major target for the agricultural industry for decades. Many approaches
(including traditional and mutational breeding as well as genetic engineering) have been tried,
typicaUy with modest success (Xu e a/., 2008, Plant Biotechnol J., 6:799-81 8 and references
therein).
Although Uquid bio fuels offer considerable promise the reaUty of utilising biological material is
tempered by competing uses and the quantities avaUable. Consequently, engineering plants and
microorganisms to address this is the focus of multiple research groups; in particular the
accumulation of triacylglcerol (TAG) in vegetative tissues and oleaginous yeasts and bacteria
(Fortman et a/., 2008, Trends Biotechnol 26, 375-381 ; Ohlrogge et a/., 2009, Science 324, 1019-
1020). TAG is a neutral Upid with twice the energy density of ceUulose and can be used to
generate biodiesel a high energy density desirable biofuel with one of the simplest and most
efficient manufacturing processes. Engineering TAG accumulation in leaves has so far resulted
in a 5-20 fold increase over WT utilising a variety of strategies which includes: the overexpression
of seed development transcription factors (LEC1, LEC2 and WRI1); sUencing of
APS (a key gene involved in starch biosynthesis); mutation of CGI-58 (a regulator of neutral Upid
accumulation); and upregulation of the TAG synthesising enzyme DGAT (diacylglycerol O
acyltransferase, EC 2.3.1 .20) in plants and also in yeast (Andrianov et a , 2009, Plant Biotech J 8,
1-1 1;Mu et a , 2008, Plant Physiol 148, 1042-1 054; Sanjaya et a/, 201 1, Plant Biotech J 9, 874-
883; Santos-Mendoza, et a/, 2008, Plant J 54, 608-620; James et a/, 2010, Proc. Natl. Acad. Sci.
USA 107, 17833-17838; Beopoulos et a/, 201 1, Appl Microbiol Biotechnol 90, 1193-1206;
Bouvier-Nave et a/, 2000, Eur J Biochem 267, 85-96; Durrett et a/, 2008, Plant J 54, 593-607).
However, it has been acknowledged that to achieve further increases in TAG, preventing its
catabolism may be crucial within non oleaginous tissues and over a range of developmental
stages (Yang and Ohlrogge, 2009, Plant Physiol 50, 981- 989).
Positively manipulating the yield and quality of triacylglycderides (TAG) in eukaryotes is difficult
to achieve. The enzyme diacylglycerol-O-acyltransferase (DGAT) has the lowest specific activity
of the Kennedy pathway enzymes and is regarded as a 'bottleneck' in TAG synthesis.
Attempts have been made previously to improve DGATl by biotechnological methods, with
limited success. For example Nykiforuk et al., (2002, Biochimica et Biophysica Acta 580:95-
109) reported N-terminal truncation of the Brassica napus DGATl but reported approximately
50% lower activity. McFie et a/., (2010, JBC, 285:37377-37387) reported that N-terminal
truncation of the mouse DGATl resulted in increased specific activity of the enzyme, but also
reported a large decline in the level of protein that accumulated.
Xu e a/., (2008, Plant Biotechnology Journal, 6:799-81 8) recently identified a consensus sequence
(X-Leu-X-Lys-X-X-Ser-X-X-X-Val) within Tropaeolum majus (garden nasturtium) DGATl
(TmDGATl) sequences as a targeting motif typical of members of the SNF -related protein
kinase- (SnRKl) with Ser being the residue for phosphorylation. The SnRK proteins are a
class of Ser/Thr protein kinases that have been increasingly implicated in the global regulation of
carbon metabolism in plants, e.g. the inactivation of sucrose phosphate synthase by
phosphorylation (Halford & Hardie 1998, Plant Mol Biol. 37:735-48. Review). Xu et al., (2008,
Plant Biotechnology Journal, 6:799-81 8) performed site-directed mutagenesis on six putative
functional regions /motifs of the TmDGATl enzyme. Mutagenesis of a serine residue (S197) in a
putative SnRKl target site resulted in a 38%-80% increase in DGATl activity, and overexpression
of the mutated TmDGATl in Arabidopsis resulted in a 20%-50% increase in oil
content on a per seed basis.
It would be beneficial to provide improved forms of DGATl, which overcome one or more of
the deficiencies in the prior art, and which can be used to increase cellular oil production.
It is an object of the invention to provide enhanced DGATl proteins and methods for their use
to alter at least one of cellular lipid production and cellular lipid profile, and/ or at least to
provide the public with a useful choice.
SUMMARY OF THE INVENTION
The inventors have shown that it is possible to produce chimeric DGATl proteins with
advantageous properties over either of the parental DGATl molecules used to produce the
chimeric DGATl proteins. The chimeric DGATl proteins of the invention can be expressed
in cells to alter lipid content and lipid profile of the cells, or organisms containing the cells.
Poyl nucleotide encoding a poylpeptide
In the first aspect the invention provides an isolated polynucleotide encoding a chimeric
DGATl protein that comprises:
a) at its N-terminal end, an N-terminal portion of a first DGATl protein, and
b) at its C-terminal end, a C-terminal portion of a second DGATl protein.
In one embodiment the chimeric DGATl protein has at least one of:
i) increased DGATl activity
it) increased stability
iit) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to the first DGATl, the second DGATl, or both the first DGATl and the second
DGATl.
In a further embodiment the chimeric DGATl protein has at least one of:
i) increased DGATl activity
it) increased stability
ii ) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to the first DGATl.
In a further embodiment the chimeric DGATl protein has at least one of:
i) increased DGATl activity
it) increased stability
iit) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to the second DGATl.
In a further embodiment the chimeric DGATl protein has at least one of:
i) increased DGATl activity
it) increased stability
iit) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to both the first DGATl and the second DGATl.
In one embodiment the the N-terminal portion of a first DGATl protein is the N-terminal
cytoplasmic region of the first DGATl protein. In one embodiment the N-terminal cytoplasmic
region of the first DGATl protein extends from the N-terminus of the first DGATl protein to
the end of the acyl-CoA binding domain of the first DGATl protein. In a further embodiment
the N-terminal cytoplasmic region of the first DGATl protein is the region upstream of the first
transmembrane domain.
The position of the acyl-CoA binding domain and the first transmembrane domain, for a
number of DGATl proteins, is shown in Figure 3.
In one embodiment the junction between the N-terminal portion of a first DGATl protein and
the C-terminal portion of a second DGATl protein is upstream of the first transmembrane
domain.
In a further embodiment the junction between the N-terminal portion of a first DGATl protein
and the C-terminal portion of a second DGATl protein is in the acyl-CoA binding site of first
and second DGATl protein.
In a further embodiment the junction between the N-terminal portion of a first DGATl protein
and the C-terminal portion of a second DGATl protein is at a corresponding poition in the acyl-
CoA binding site of the first and second DGATl protein.
In one embodiment the junction between the N-terminal portion of a first DGATl protein and
the C-terminal portion of a second DGATl protein is within the conserved LSS (Leu-Ser-Ser) in
the acyl-CoA binding site of the first and second DGATl protein.
In a preferred embodiment the chimeric DGATl has an intact acyl-CoA binding site.
In one embodiment the acyl-CoA binding site in the chimeric DGATl is of the same length as
the acyl-CoA binding site in the first DGATl protein.
In a further embodiment the acyl-CoA binding site in the chimeric DGATl is of the same length
as the acyl-CoA binding site in the second DGATl protein.
In a preferred embodiment the acyl-CoA binding site in the chimeric DGATl is of the same
length as the acyl-CoA binding site in the first and second DGATl protein.
In a further embodiment the polypeptide of the invention, when expressed in the cell, has altered
substrate specificity relative to at least one of the first and second DGATl proteins.
Construct
In a further embodiment the invention provides a genetic construct comprising a polynucleotide
of the invention.
Cells
In a further embodiment the invention provides a cell comprising a polynucleotide of the
invention.
In a further embodiment the invention provides a cell comprising a genetic construct of the
invention.
In a preferred embodiment the cell expresses the chimeric DGATl.
In one embodiment the chimeric DGATl protein, when expressed in the cell, has at least one
of:
i) increased DGATl activity,
it) increased stability,
iit) altered oligomerisation properties,
iv) substantially normal cellular protein accumulation properties, and
v) substantially normal subcellular targeting properties
relative to the first DGATl, the second DGATl, or both the first DGATl and the second
DGATl.
In one embodiment the chimeric DGATl protein, when expressed in the cell, has at least one
of:
i) increased DGATl activity,
it) increased stability,
ii ) altered oligomerisation properties,
iv) substantially normal cellular protein accumulation properties, and
v) substantially normal subcellular targeting properties
relative to the first DGATl when expressed in a cell.
In one embodiment the chimeric DGATl protein, when expressed in the cell, has at least one
of:
i) increased DGATl activity,
it) increased stability,
iit) altered oligomerisation properties,
iv) substantially normal cellular protein accumulation properties, and
v) substantially normal subcellular targeting properties
relative to the second DGATl when expressed in a cell.
In a further embodiment the chimeric DGATl protein has at least one of:
i) increased DGATl activity
it) increased stability
iit) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to both the first DGAT1 and the second DGAT1.
In a further embodiment the cell produces more lipid than does a control cell.
In one embodiment the cell produces at least 5% more, preferably at least 10% more, preferably
at least 5% more, preferably at least 20% more, preferably at least 25% more, preferably at least
30% more, preferably at least 35% more, preferably at least 40% more, preferably at least 45%
more, preferably at least 50% more, preferably at least 55% more, preferably at least 60% more,
preferably at least 65% more, preferably at least 70% more, preferably at least 75% more,
preferably at least 80% more, preferably at least 85% more, preferably at least 90% more,
preferably at least 95% more preferably at least 100% more, preferably at least 105% more,
preferably at least 110% more, preferably at least 115% more, preferably at least 120% more,
preferably at least 125% more, preferably at least 130% more, preferably at least 135% more,
preferably at least 140% more, preferably at least 145% more, preferably at least 150% more lipid
than does a control cell.
In a further embodiment the cell has an altered lipid profile relative to a control cell.
In one embodiment the proportion of 16:0 in the triacylglycerol is altered relative to that in a
control cell.
In one embodiment the proportion of 16:0 in the triacylglycerol is altered by at least 1%,
preferably at least 2%, more preferably at least 3%, more preferably at least 4%, more preferably
at least 5%, more preferably at least 6%, more preferably at least 7%, more preferably at least
8%, more preferably at least 9%, more preferably at least 10%, more preferably at least 11%,
more preferably at least 12%, more preferably at least 13%, more preferably at least 14%, more
preferably at least 5%, more preferably at least 6%, more preferably at least 7%, more
preferably at least 8%, more preferably at least 9%, more preferably at least 20%, relative to
that in a control cell.
In a further embodiment the altered lipid profile has a proportion of 16:0 in the triacylglycerol in
the range 6% to 16%. In this embodiment the proportion of 16:0 in the triacylglycerol is altered
within the range 6% to 6%.
In a further embodiment the proportion of 18:0 in the triacylglycerol is altered relative to that in
a control cell.
In one embodiment the proportion of 18:0 in the triacylglycerol is altered by at least 1%,
preferably at least 2%, more preferably at least 3%, more preferably at least 4%, more preferably
at least 5%, more preferably at least 6%, more preferably at least 7%, more preferably at least
8%, more preferably at least 9%, more preferably at least 10%, more preferably at least 11%,
more preferably at least 12%, more preferably at least 13%, more preferably at least 14%, more
preferably at least 5%, more preferably at least 6%, more preferably at least 7%, more
preferably at least 8%, more preferably at least 9%, more preferably at least 20%, relative to
that in a control cell.
In a further embodiment the altered lipid profile has a proportion of 18:0 in the triacylglycerol in
the range 7% to 15%. In this embodiment the proportion of 18:0 in the triacylglycerol is altered
within the range 7% to 5%.
In a further embodiment the proportion of 18:1 in the triacylglycerol is altered relative to that in
a control cell.
In one embodiment the proportion of 18:1 in the triacylglycerol is altered by at least 1%,
preferably at least 2%, more preferably at least 3%, more preferably at least 4%, more preferably
at least 5%, more preferably at least 6%, more preferably at least 7%, more preferably at least
8%, more preferably at least 9%, more preferably at least 10%, more preferably at least 11%,
more preferably at least 12%, more preferably at least 13%, more preferably at least 14%, more
preferably at least 5%, more preferably at least 6%, more preferably at least 7%, more
preferably at least 8%, more preferably at least 9%, more preferably at least 20%, relative to
that in a control cell.
In a further embodiment the altered lipid profile has a proportion of 18:1 in the triacylglycerol in
the range 39% to 55%. In this embodiment the proportion of 18:1 in the triacylglycerol is
altered within the range 39% to 55%.
The control cell may be any cell of the same type that is not transformed with the
polynucleotide, or construct, of the invention to express the chimeric DGATl.
In one embodiment the control cell is an untransformed cell. In a further embodiment the
control cell is transformed cell to express the first DGATl. In a further embodiment the control
cell is transformed cell to express the second DGATl.
Cells also transformed to express an oleosin
In one embodiment the cell is also transformed to express at least one of: an oleosin, steroleosin,
caloleosin, polyoleosin, and an oleosin including at least one artificially introduced cysteine
(WO2011/053169).
Plant
In a further embodiment the invention provides a plant comprising a polynucleotide of the
invention.
In a further embodiment the invention provides a plant comprising a genetic construct of the
invention.
In a preferred embodiment the plant expresses the chimeric DGATl.
In one embodiment the chimeric DGATl protein when expressed in the plant has at least one
of:
i) increased DGATl activity,
ii) increased stability,
iii) altered oligomerisation properties,
iv) substantially normal cellular protein accumulation properties, and
v) substantially normal subcellular targeting properties
relative to the first DGATl, the second DGATl, or both the first DGATl and the second
DGATl.
In one embodiment the chimeric DGATl protein when expressed in the plant has at least one
of:
i) increased DGATl activity,
ii) increased stability,
iii) altered oligomerisation properties,
iv) substantially normal cellular protein accumulation properties, and
v) substantially normal subcellular targeting properties
relative to the first DGAT1.
In one embodiment the chimeric DGAT1 protein when expressed in the plant has at least one
of:
i) increased DGAT1 activity,
it) increased stability,
iii) altered oligomerisation properties,
iv) substantially normal cellular protein accumulation properties, and
v) substantially normal subcellular targeting properties
relative to the second DGAT1.
In one embodiment the chimeric DGAT1 protein when expressed in the plant has at least one
of:
i) increased DGAT1 activity,
it) increased stability,
iii) altered oligomerisation properties,
iv) substantially normal cellular protein accumulation properties, and
v) substantially normal subcellular targeting properties
relative to both the first DGAT1 and the second DGAT1.
In one embodiment the chimeric DGAT1 protein when expressed in the plant has at least one
of:
i) increased DGAT1 activity,
it) increased stability,
iii) altered oligomerisation properties,
iv) substantially normal cellular protein accumulation properties, and
v) substantially normal subcellular targeting properties
relative to both the first DGAT1 and the second DGAT1.
In a further embodiment the plant produces more lipid, in at least one of its tissues or parts, than
does the equivalent tissue or part in a control plant.
In one embodiment the plant produces at least 5% more, preferably at least 10% more,
preferably at least 5% more, preferably at least 20% more, preferably at least 25% more,
preferably at least 30% more, preferably at least 35% more, preferably at least 40% more,
preferably at least 45% more, preferably at least 50% more, preferably at least 55% more,
preferably at least 60% more, preferably at least 65% more, preferably at least 70% more,
preferably at least 75% more, preferably at least 80% more, preferably at least 85% more,
preferably at least 90% more, preferably at least 95% more preferably at least 100% more,
preferably at least 105% more, preferably at least 110% more, preferably at least 115% more,
preferably at least 120% more, preferably at least 125% more, preferably at least 130% more,
preferably at least 135% more, preferably at least 140% more, preferably at least 145% more,
preferably at least 50% more lipid than does a control cell.
In one embodiment the tissue is a vegetative tissue. In one embodiment the part is a leaf. In a
further embodiment the part is a root. In a further embodiment the part is a tuber. In a further
embodiment the part is a corm. In a further embodiment the part is a stalk. In a further
embodiment the part is a stalk of a monoct plant. In a further embodiment the part is a stovum
(stalk and leaf blade).
In a preferred embodiment the tissue is seed tissue. In a preferred embodiment the part is a
seed. In a preferred embodiment the tissue is endosperm tissue.
In a further embodiment the plant as a whole produces more lipid than does the control plant as
a whole.
In a further embodiment the plant has an altered lipid , in at least one of its tissues or parts,
relative to a control plant.
In one embodiment the proportion of 16:0 in the triacylglycerol is altered relative to that in a
control plant.
In one embodiment the proportion of 16:0 in the triacylglycerol is altered by at least 1%,
preferably at least 2%, more preferably at least 3%, more preferably at least 4%, more preferably
at least 5%, more preferably at least 6%, more preferably at least 7%, more preferably at least
8%, more preferably at least 9%, more preferably at least 10%, more preferably at least 11%,
more preferably at least 12%, more preferably at least 13%, more preferably at least 14%, more
preferably at least 5%, more preferably at least 6%, more preferably at least 7%, more
preferably at least 8%, more preferably at least 9%, more preferably at least 20%, relative to
that in a control cell.
In one embodiment the altered lipid profile has a proportion of 16:0 in the triacylglycerol in the
range 6% to 16%. In this embodiment the proportion of 16:0 in the triacylglycerol is altered
within the range 6% to 6%.
In a further embodiment the proportion of 18:0 in the triacylglycerol is altered relative to that in
a control plant.
In one embodiment the proportion of 18:0 in the triacylglycerol is altered by at least 1%,
preferably at least 2%, more preferably at least 3%, more preferably at least 4%, more preferably
at least 5%, more preferably at least 6%, more preferably at least 7%, more preferably at least
8%, more preferably at least 9%, more preferably at least 10%, more preferably at least 11%,
more preferably at least 12%, more preferably at least 13%, more preferably at least 14%, more
preferably at least 5%, more preferably at least 6%, more preferably at least 7%, more
preferably at least 8%, more preferably at least 9%, more preferably at least 20%, relative to
that in a control cell.
In one embodiment the altered lipid profile has a proportion of 18:0 in the triacylglycerol in the
range 7% to 15%. In this embodiment the proportion of 18:0 in the triacylglycerol is altered
within the range 7% to 5%.
In a further embodiment the proportion of 18:1 in the triacylglycerol is altered relative to that in
a control plant.
In one embodiment the proportion of 18:1 in the triacylglycerol is altered by at least 1%,
preferably at least 2%, more preferably at least 3%, more preferably at least 4%, more preferably
at least 5%, more preferably at least 6%, more preferably at least 7%, more preferably at least
8%, more preferably at least 9%, more preferably at least 10%, more preferably at least 11%,
more preferably at least 12%, more preferably at least 13%, more preferably at least 14%, more
preferably at least 5%, more preferably at least 6%, more preferably at least 7%, more
preferably at least 8%, more preferably at least 9%, more preferably at least 20%, relative to
that in a control cell.
In one embodiment the altered lipid profile has a proportion of 18:1 in the triacylglycerol in the
range 39% to 55%. In this embodiment the proportion of 18:1 in the triacylglycerol is altered
within the range 39% to 55%.
In one embodiment the tissue is a vegetative tissue. In one embodiment the part is a leaf. In a
further embodiment the part is a root. In a further embodiment the part is a tuber. In a further
embodiment the part is a corm. In a further embodiment the part is a stalk. In a further
embodiment the part is a stalk of a monoct plant. In a further embodiment the part is a stovum
(stalk and leaf blade).
In a preferred embodiment the tissue is seed tissue. In a preferred embodiment the part is a
seed. In a preferred embodiment the tissue is endosperm tissue.
In a further embodiment the plant as a whole has an altered lipid profile relative to the control
plant as a whole.
The control plant may be any plant of the same type that is not transformed with the
polynucleotide, or construct, of the invention to express the chimeric DGATl.
In one embodiment the control plant is an untransformed plant. In a further embodiment the
control plant is transformed plant to express the first DGATl. In a further embodiment the
control plant is transformed plant to express the second DGATl.
Plant also transformed to express an oleosin
In one embodiment the plant is also transformed to express at least one of: an oleosin,
steroleosin, caloleosin, polyoleosin, and an oleosin including at least one artificially introduced
Cysteine (WO 2011/053169).
Poylpeptide
In a further aspect the invention provides a chimeric DGATl protein that comprises:
a) at its N-terminal end, an N-terminal portion of a first DGATl protein, and
b) at its C-terminal end, a C-terminal portion of a second DGATl protein.
In one embodiment the chimeric DGATl protein has at least one of:
i) increased DGATl activity
it) increased stability
iit) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to the first DGATl, the second DGATl, or both the first DGATl and the second
DGATl.
In a further embodiment the chimeric DGATl protein has at least one of:
i) increased DGATl activity
it) increased stability
iit) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to the first DGATl.
In a further embodiment the chimeric DGATl protein has at least one of:
i) increased DGATl activity
it) increased stability
iit) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to the second DGATl.
In one embodiment the chimeric DGATl protein when expressed in the plant has at least one
of:
i) increased DGATl activity,
ii) increased stability,
iii) altered oligomerisation properties,
iv) substantially normal cellular protein accumulation properties, and
v) substantially normal subcellular targeting properties
relative to both the first DGATl and the second DGATl.
In one embodiment the the N-terminal portion of a first DGATl protein is the N-terminal
cytoplasmic region of the first DGATl protein. In one embodiment the N-terminal cytoplasmic
region of the first DGATl protein extends from the N-terminus of the first DGATl protein to
the end of the acyl-CoA binding domain of the first DGATl protein. In a further embodiment
the N-terminal cytoplasmic region of the first DGATl protein is the region upstream of the first
transmembrane domain.
The position of the acyl-CoA binding domain and the first transmembrane domain, for a
number of DGATl proteins, is shown in Figure 3.
In one embodiment the junction between the N-terminal portion of a first DGATl protein and
the C-terminal portion of a second DGATl protein is upstream of the first transmembrane
domain.
In one embodiment the junction between the N-terminal portion of a first DGATl protein and
the C-terminal portion of a second DGATl protein is in the acyl-CoA binding site of first and
second DGATl protein.
In a further embodiment the junction between the N-terminal portion of a first DGATl protein
and the C-terminal portion of a second DGATl protein is at a corresponding poition in the acyl-
CoA binding site of the first and second DGATl protein.
In one embodiment the junction between the N-terminal portion of a first DGATl protein and
the C-terminal portion of a second DGATl protein is within the conserved LSS (Leu-Ser-Ser) in
the acyl-CoA binding site of the first and second DGATl protein.
In a preferred embodiment the chimeric DGATl has an intact acyl-CoA binding site.
In one embodiment the acyl-CoA binding site in the chimeric DGATl is of the same length as
the acyl-CoA binding site in the first DGATl protein.
In a further embodiment the acyl-CoA binding site in the chimeric DGATl is of the same length
as the acyl-CoA binding site in the second DGATl protein.
In a preferred embodiment the acyl-CoA binding site in the chimeric DGATl is of the same
length as the acyl-CoA binding site in the first and second DGATl protein.
Method for producing an chimeric DGAT1
In a further aspect the invention provides a method for producing a chimeric DGATl protein
the method comprising combining:
a) an N-terminal portion of a first DGATl protein, and
b) a C-terminal portion of a second DGATl protein.
In a preferred embodiment chimeric DGATl preotein comprises:
a) at its N-terminal end, the N-terminal portion of a first DGATl protein, and
b) at its C-terminal end, the C-terminal portion of a second DGATl protein.
In one embodiment the chimeric DGATl protein has at least one of:
i) increased DGATl activity
it) increased stability
iit) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to the first DGATl, the second DGATl, or both the first DGATl and the second
DGATl.
In a further embodiment the chimeric DGATl protein has at least one of:
i) increased DGATl activity
it) increased stability
iii) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to the first DGATl.
In a further embodiment the chimeric DGATl protein has at least one of:
i) increased DGATl activity
it) increased stability
iit) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to the second DGATl.
In a further embodiment the chimeric DGATl protein has at least one of:
i) increased DGATl activity
it) increased stability
iii) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to both the first DGATl and the second DGATl.
In a further embodiment the method comprises testing at least one of the
i) activity
it) stability
iii) oligomerisation properties
iv) cellular protein accumulation properties
v) cellular targeting properties
of the chimeric DGATl protein.
In a further embodiment method comprises the step selecting a chimeric DGATl protein that
has at least one of:
i) increased DGATl activity
it) increased stability
iii) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to the first DGATl, the second DGATl, or both the first DGATl and the second
DGATl.
In a further embodiment method comprises the step of selecting a chimeric DGATl protein that
has at least one of:
i) increased DGATl activity
it) increased stability
iit) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to the first DGATl protein.
In a further embodiment method comprises the step of selecting a chimeric DGATl protein that
has at least one of:
i) increased DGATl activity
it) increased stability
ii ) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to the second DGATl protein.
In a further embodiment method comprises the step of selecting a chimeric DGATl protein that
has at least one of:
i) increased DGATl activity
it) increased stability
iit) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to both the first DGATl and the second DGATl.
In one embodiment the the N-terminal portion of a first DGATl protein is the N-terminal
cytoplasmic region of the first DGATl protein. In one embodiment the N-terminal cytoplasmic
region of the first DGATl protein extends from the N-terminus of the first DGATl protein to
the end of the acyl-CoA binding domain of the first DGATl protein. In a further embodiment
the N-terminal cytoplasmic region of the first DGATl protein is the region upstream of the first
transmembrane domain.
The position of the acyl-CoA binding domain and the first transmembrane domain, for a
number of DGATl proteins, is shown in Figure 3.
In one embodiment the junction between the N-terminal portion of a first DGATl protein and
the C-terminal portion of a second DGATl protein is upstream of the first transmembrane
domain.
In one embodiment the junction between the N-terminal portion of a first DGATl protein and
the C-terminal portion of a second DGATl protein is in the acyl-CoA binding site of first and
second DGATl protein.
In a further embodiment the junction between the N-terminal portion of a first DGATl protein
and the C-terminal portion of a second DGATl protein is at a corresponding poition in the acyl-
CoA binding site of the first and second DGATl protein.
In one embodiment the junction between the N-terminal portion of a first DGATl protein and
the C-terminal portion of a second DGATl protein is within the conserved LSS (Leu-Ser-Ser) in
the acyl-CoA binding site of the first and second DGATl protein.
In a preferred embodiment the chimeric DGATl has an intact acyl-CoA binding site.
In one embodiment the acyl-CoA binding site in the chimeric DGATl is of the same length as
the acyl-CoA binding site in the first DGATl protein.
In a further embodiment the acyl-CoA binding site in the chimeric DGATl is of the same length
as the acyl-CoA binding site in the second DGATl protein.
In a preferred embodiment the acyl-CoA binding site in the chimeric DGATl is of the same
length as the acyl-CoA binding site in the first and second DGATl protein.
Plantparts
In a further embodiment the invention provides a part, propagule or progeny of a plant of the
invention.
In a preferred embodiment the part, propagule or progeny comprises at least one of a
polynucleotide, construct or polypeptide of the invention.
In a preferred embodiment the part, propagule or progeny expressees at least one of a
polynucleotide, construct or polypeptide of the invention.
In a preferred embodiment the part, propagule or progeny expresses a chimeric DGATl protein
of the invention.
In a further embodiment the part, propagule or progeny produces more lipid than does a control
part, propagule or progeny, or part, propagule or progeny of a control plant.
In one embodiment the part, propagule or progeny produces at least 5% more, preferably at least
10% more, preferably at least 15% more, preferably at least 20% more, preferably at least 25%
more, preferably at least 30% more, preferably at least 35% more, preferably at least 40% more,
preferably at least 45% more, preferably at least 50% more, preferably at least 55% more,
preferably at least 60% more, preferably at least 65% more, preferably at least 70% more,
preferably at least 75% more, preferably at least 80% more, preferably at least 85% more,
preferably at least 90% more, preferably at least 95% more preferably at least 100% more,
preferably at least 105% more, preferably at least 110% more, preferably at least 115% more,
preferably at least 120% more, preferably at least 125% more, preferably at least 130% more,
preferably at least 135% more, preferably at least 140% more, preferably at least 145% more,
preferably at least 150% more lipid than does a control part, propagule or progeny, or part,
propagule or progeny of a control plant.
In a further embodiment the part, propagule or progeny has an altered lipid profile relative to a
control part, propagule or progeny, or part, propagule or progeny of a control plant.
In one embodiment the proportion of 16:0 in the triacylglycerol is altered relative to that in a
control part, propagule or progeny, or part, propagule or progeny of a control plant.
In one embodiment the proportion of 16:0 in the triacylglycerol is altered by at least 1%,
preferably at least 2%, more preferably at least 3%, more preferably at least 4%, more preferably
at least 5%, more preferably at least 6%, more preferably at least 7%, more preferably at least
8%, more preferably at least 9%, more preferably at least 10%, more preferably at least 11%,
more preferably at least 12%, more preferably at least 13%, more preferably at least 14%, more
preferably at least 15%, more preferably at least 16%, more preferably at least 17%, more
preferably at least 8%, more preferably at least 9%, more preferably at least 20%, relative to
that in a control part, propagule or progeny, or part, propagule or progeny of a control plant.
In a further embodiment the altered lipid profile has a proportion of 16:0 in the triacylglycerol in
the range 6% to 16%. In this embodiment the proportion of 16:0 in the triacylglycerol is altered
within the range 6% to 6%.
In a further embodiment the proportion of 18:0 in the triacylglycerol is altered relative to that in
a control part, propagule or progeny, or part, propagule or progeny of a control plant.
In one embodiment the proportion of 18:0 in the triacylglycerol is altered by at least 1%,
preferably at least 2%, more preferably at least 3%, more preferably at least 4%, more preferably
at least 5%, more preferably at least 6%, more preferably at least 7%, more preferably at least
8%, more preferably at least 9%, more preferably at least 10%, more preferably at least 11%,
more preferably at least 12%, more preferably at least 13%, more preferably at least 14%, more
preferably at least 5%, more preferably at least 6%, more preferably at least 7%, more
preferably at least 8%, more preferably at least 9%, more preferably at least 20%, relative to
that in a control part, propagule or progeny, or part, propagule or progeny of a control plant.
In a further embodiment the altered lipid profile has a proportion of 18:0 in the triacylglycerol in
the range 7% to 15%. In this embodiment the proportion of 18:0 in the triacylglycerol is altered
within the range 7% to 5%.
In a further embodiment the proportion of 18:1 in the triacylglycerol is altered relative to that in
a control part, propagule or progeny, or part, propagule or progeny of a control plant.
In one embodiment the proportion of 18:1 in the triacylglycerol is altered by at least 1%,
preferably at least 2%, more preferably at least 3%, more preferably at least 4%, more preferably
at least 5%, more preferably at least 6%, more preferably at least 7%, more preferably at least
8%, more preferably at least 9%, more preferably at least 10%, more preferably at least 11%,
more preferably at least 12%, more preferably at least 13%, more preferably at least 14%, more
preferably at least 5%, more preferably at least 6%, more preferably at least 7%, more
preferably at least 8%, more preferably at least 9%, more preferably at least 20%, relative to
that in a control part, propagule or progeny, or part, propagule or progeny of a control plant.
In a further embodiment the altered lipid profile has a proportion of 18:1 in the triacylglycerol in
the range 39% to 55%. In this embodiment the proportion of 18:1 in the triacylglycerol is
altered within the range 39% to 55%.
The control plant may be any plant of the same type that is not transformed with the
polynucleotide, or construct, of the invention to express the chimeric DGAT1.
In one embodiment the control plant is an untransformed plant. In a further embodiment the
control plant is transformed plant to express the first DGAT1 protein. In a further embodiment
the control plant is transformed plant to express the second DGAT1 protein.
Preferably the control the part, propagule or progeny is from a control plant as described above.
In one embodiment the part is from a vegetative tissue. In one embodiment the part is a leaf. In
a further embodiment the part is a root. In a further embodiment the part is a tuber. In a
further embodiment the part is a corm. In a further embodiment the part is a stalk. In a further
embodiment the part is a stalk of a monocot plant. In a further embodiment the part is a
stovum (stalk and leaf blade).
In a further embodiment the part is from a reproductive tissue. In a further embodiment the
part is a seed. In a preferred embodiment the part is from or includes endosperm tissue.
Animal feed
In a further aspect the invention provides an animal feedstock comprising at least one of a
polynucleotide, construct, cell, plant cell, plant part, propagule and progeny of the invention.
Biofuelfeedstock
In a further aspect the invention provides a biofuel feedstock comprising at least one of a
polynucleotide, construct, cell, plant cell, plant part, propagule and progeny of the invention.
Upid
In one embodiment the lipid is an oil. In a further embodiment the lipid is triacylglycerol (TAG)
Methodsfor producing lipid
In a further aspect the invention provides a method for producing lipid, the method comprising
expressing a chimeric DGATl protein of the invention in a plant.
In a preferred embodiment expressing the chimeric DGATl protein of the invention in the plant
leads production of the lipid in the plant.
In one embodiment the method includes the step of transforming a plant cell or plant with a
polynucleotide of the invention encoding the chimeric DGATl protein.
In a further embodiment the method includes the step of extracting the lipid from from the cell,
plant cell, or plant, or from a part, propagule or progeny of the plant.
In one embodiment the lipid is an oil. In a further embodiment the lipid is triacylglycerol (TAG)
In a further embodiment the lipid is processed into at least one of:
a) a fuel,
b) an oleochemical,
c) a nutritional oil,
d) a cosmetic oil,
e) a polyunsaturated fatty acid (PUFA), and
f a combination of any of a) to e).
In a further aspect the invention provides a method for producing lipid, the method comprising
extracting lipid from at least one of a cell, plant cell, plant, plant part, propagule and progeny of
the invention.
In one embodiment the lipid is an oil. In a further embodiment the lipid is triacylglycerol (TAG)
In a further embodiment the lipid is processed into at least one of:
a) a fuel,
b) an oleochemical,
c) a nutritional oil,
d) a cosmetic oil,
e) a polyunsaturated fatty acid (PUFA), and
f ) a combination of any of a) to e).
DETAILED DESCRIPTION OF THE INVENTION
In this specification where reference has been made to patent specifications, other external
documents, or other sources of information, this is generally for the purpose of providing a
context for discussing the features of the invention. Unless specifically stated otherwise,
reference to such external documents is not to be construed as an admission that such
documents, or such sources of information, in any jurisdiction, are prior art, or form part of the
common general knowledge in the art.
The term "comprising" as used in this specification means "consisting at least in part of. When
interpreting each statement in this specification that includes the term "comprising", features
other than that or those prefaced by the term may also be present. Related terms such as
"comprise" and "comprises" are to be interpreted in the same manner. In some embodiments,
the term "comprising" (and related terms such as "comprise and "comprises") can be replaced by
"consisting of (and related terms "consist" and "consists").
Definitions
The term "DGATl" as used herein means acyl CoA: diacylglycerol acyltransferase (EC 2.3.1.20)
DGATl is typically the major TAG synthesising enzyme in both the seed and senescing leaf
(Kaup eta/., 2002, Plant Physiol. 129(4):1616-26; for reviews see Lung and Weselake 2006,
Lipids. 41(12):1073-88; Cahoon eta/., 2007, Current Opinion in Plant Biology. 10:236-244; and Li
eta/., 2010, Lipids. 45:145-157).
DGATl contains approximately 500 amino acids and has 10 predicted transmembrane domains
whereas DGAT2 has only 320 amino acids and is predicted to contain only two transmembrane
domains; both proteins were also predicted to have their N- and C-termini located in the
cytoplasm (Shockey et al., 2006, Plant Cell 18:2294-2313). Both DGAT1 and DGAT2 have
orthologues in animals and fungi and are transmembrane proteins located in the ER.
In most dicotyledonous plants DGAT1 & DGAT2 appear to be single copy genes whereas there
are typically two versions of each in the grasses which presumably arose during the duplication
of the grass genome (Salse e /., 2008, Plant Cell, 20:11-24).
The term "first DGATl protein" or "second DGATl protein" as used herein typically means a
naturally occurring or native DGATl. In some cases the DGATl sequence may have been
assembled from sequences in the genome, but may not be expressed in plants. In one
embodiment the first or second DGATl protein may therefore not be a DGATl that is isolated
from nature.
In one embodiment the "first DGATl protein" or "second DGATl protein" has the sequence
of any one of SEQ ID NO: 1 to 29 or a variant thereof. Preferably the variant has at least 70%
identity to any one of SEQ ID NO: 1 to 29. In a further embodiment the "first DGATl
protein" or "second DGATl protein" has the sequence of any one of SEQ ID NO: 1 to 29.
In one embodiment "first DGATl protein" or "second DGATl protein" is encoded by a
polynucleotide comprising the sequence of any one of SEQ ID NO: 30 to 58 or a variant
thereof. Preferably the variant has at least 70% identity to any one of SEQ ID NO: 30 to 58. In
a further embodiment the "first DGATl protein" or "second DGATl protein" is encoded by a
polynucleotide comprising the sequence of any one of SEQ ID NO: 30 to 58.
In one embodiment the chimeric DGATl sequences comprises the sequence of any SEQ ID
NO: 59 to 94 or a variant thereof. Preferably the variant has at least 70% identity to any one of
SEQ ID NO: 59 to 94. In a further embodiment the chimeric DGATl sequences the sequence
of any one of SEQ ID NO: 59 to 94.
In a further embodiment the chimeric DGATl polypeptide sequences have the sequence of any
SEQ ID NO: 59, 61, 66, 68, 70-72, 74- 76, 78, 79, 82, 84-86, 88-90, 92 and 93 or a variant
thereof. Preferably the variant has at least 70% identity to any one of SEQ ID NO: 59, 61, 66,
68, 70-72, 74- 76, 78, 79, 82, 84-86, 88-90, 92 and 93. In a further embodiment the chimeric
DGATl sequences have the sequence of any one of SEQ ID NO: 59, 61, 66, 68, 70-72, 74- 76,
78, 79, 82, 84-86, 88-90, 92 and 93.
Although not preferred, the chimeric DGATl of the invention may include further
modifications in at least one of:
a) the N-terminal portion of a first DGATl protein, and
b) the C-terminal portion of a second DGATl protein.
Preferably the chimeric DGATl of the invention includes a functional acyl -CoA binding site.
The terms upstream and downstream are according to normal convention to mean towards the
N-terminus of a polypeptide, and towards the C-terminus of a polypeptide, respectively.
Acyl-CoA binding site
The position of the acycl-CoA binding site in a number of DGATl sequences is shown if Figure
3.
Conserved motif E SPI
In a preferred embodiment the acycl-CoA binding site comprises the conserved motif ESPLSS
Acyl-CoA binding site generalformulae
In a preferred embodiment the acyl-CoA binding site in the chimeric DGATlhas the formula:
XXXESPLSSXXIFXXXHA,
where X is any amino acid.
In a preferred embodiment the acyl-CoA binding site in the chimeric DGATlhas the formula:
XXXESPLSSXXIFXXSHA,
where X is any amino acid.
In a preferred embodiment the acyl-CoA binding site in the chimeric DGATlhas the formula:
where X = R, K, V, T, A, S or G; X2 = A, T, V, I, N, R, S or L; X3 = R or K; X4 = D or G;
X5 = A, T, N, or L; X = K or R; X = Q or H; and X8 = S or is absent.
In a preferred embodiment the acyl-CoA binding site in the chimeric DGATlhas the formula:
X^^ESPLSSX^IFX^SHA,
where X = R, K, V, T, A, S or G; X2 = A, T, V, I, N, R, S or L; X3 = R or K; X4 = D or G;
X5 = A, T, N, or L; X = K or R; and X7 = Q or H.
Methodsfor producing chimeric DGATl proteins
Methods for producing chimeric proteins, or the polynucleotide sequences encoding them, are
well known to those skilled in the art. A chimeric DGATl protein may be conveniently be
produced by combining, using standard molecular biological techniques such as restriction
digestion and ligation, sequences encoding DGATl proteins, and then expressing the chimeric
DGATl protein. Alternatively polynucleotide sequences encoding the chimeric DGATl
proteins may be conveniently synthesised, and the chimeric proteins expressed from the
synthesised sequences. For making multiple chimeric DGATl proteins the encoding sequences
can be synthesised to include restriction sites that do not alter the amino acid sequence of the
expressed proteins. These restrictions sites can be utilised to combine sequences for production
and expression of the chimeric proteins. These and similar methods for producing chimeric
proteins are known to those skilled in the art.
The first and second DGATl protein sequences, and encoding polynucleotides, used to produce
the chimeric DGATl proteins of the invention, may be selected from those disclosed herein.
Alternatively further DGATl sequences can be identified by methods well known to those
skilled in the art, including bioinformatic database searching , as well as physical cloning
methods. The first and second DGATl protein sequences may be from any species, including
plants, animals and microorganisms.
The phrase "increased DGATl activity" means increased specific activity relative to that of the
first and/ or DGATl protein.
An art skilled worker would know how to test the "specific activity" of the chimeric DGATl.
This may typically be done by isolating, enriching and quantifying the recombinant DGATl then
using this material to determine either the rate of triaclyglyceride formation and/ or the
disappearance of precursor substrates (including various forms of acyl-CoA and DAG) as per Xu
et al., (2008), Plant Biotechnology Journal. 6:799-818.
The phrase "increased stability" means that the chimeric DGATl protein is more stable, when
expressed in a cell, than the first and/or second DGATl. This may lead to increased
accumulation of active chimeric DGATl when it is expressed in cells, releative to when the first
and/ or second DGATl is expressed in cells.
Those skilled in the art know how to test the "stability" of the chimeric DGATl. This would
typically involve expressing the chimeric DGATl in a cell, or cells, and expressing the first or
second DGATl in a separate cell, or cells of the same type. Accumulation of chimeric and the
first or second DGATl protein in the respective cells can then be measured, for example by
immunoblot and/ or ELISA. A higher level of accumulation of the chimeric DGATl relative to
the first or second DGATl, at the same time point, indicates that the chimeric DGATl has
increased stability. Alternatively, stability may also be determined by the formation of quaternary
structure which can also be determined by immunoblot analysis.
The phrase "altered oligomerisation properties" means that the way in which, or the extent to
which chimeric DGATl forms oligomers is altered relative to the first and/or second DGATl.
Those skilled in the art know know how to test the " oligomerisation properties" of the chimeric
DGATl. This may typically be done by immunoblot analysis or size exclusion chromatography.
The phrase "substantially normal cellular protein accumulation properties" means that the
chimeric DGATl of the invention retains substantially the same protein accumulation when
expressed in a cell, as does the first and/or second DGATl. That is there is no less
accumulation of chimeric DGATl than there is accumulation of first and/or second DGATl,
when either are separately expressed in the same cell type.
An art skilled worker would know how to test the "cellular protein accumulation properties" of
the chimeric DGATl. This would typically involve expressing the chimeric DGATl in a cell, or
cells, and expressing the first or second DGATl in a separate cell, or cells of the same type.
Accumulation of chimeric and the first or second DGATl protein in the respective cells can
then be measured, for example by ELISA or immunoblot. A substantially similar level of
accumulation of the chimeric DGATl relative to the the first or second DGATl, at the same
time point, indicates that the chimeric DGATl has increased "substantially normal cellular
protein accumulation properties".
The phrase "substantially normal subcellular targetting properties" means that the chimeric
DGATl of the invention retains substantially the same subcellular targetting when expressed in a
cell, as does the first and/or second DGATl. That is the chimeric DGATl is targeted to the
same subcellular compartment/ s as the first and/or second DGATl, when either are separately
expressed in the same cell type.
An art skilled worker would know how to test the "subcellular targetting properties " of the
chimeric DGATl. This would typically involve expressing the chimeric DGATl in a cell, or
cells, and expressing the first or second DGATl in a separate cell, or cells of the same type.
Subcellular targetting of chimeric and the first or second DGATl protein in the respective cells
can then be assessed, for example by using ultracentrifugation to separate and isolating individual
subcellular fractions then determining the level of DGATl in each fraction. Substantially
similar " subcellular targeting" of the chimeric DGATl relative to the the first or second
DGATl, at the same time point, indicates that the chimeric DGATl has increased "substantially
normal cellular protein has "substantially normal subcellular targetting properties".
Upid
In one embodiment the lipid is an oil. In a further embodiment the oil is triacylglycerol (TAG)
Upid production
In certain embodiments the cell, cells, tissues, plants and plant parts of the invention produces
more lipid than control cells, tissues, plants and plant parts.
Those skilled in the art are well aware of methods for measuring lipid production. This may
typically be done by quantitative fatty acid methyl ester gas chromatography mass spectral
analysis (FAMES GC-MS). Suitable methods are also described in the examples section of this
specification.
Substrate specificity
In certain embodiments, the polypeptides of the invention have altered substrate specificity
relative to parent DGAT1 proteins. Plant DGAT1 proteins are relatively promiscuous in terms
of the fatty acid substrates and DAG species they are capable of utilisting to generate TAG. As
such they can be considered to have relatively low substrate specificity. However, this can be
modified such that certain fatty acids become a preferred substrate over others. This leads to an
increase in the proportions of the preferred fatty acids in the TAG and decreases in the
proportions of the non preferred fatty acid species. Substrate specificity can be determined by
in vitro quantitiative analysis of TAG production following the addition of specific and known
quantities of purified substrates to known quantities of recombinant DGAT, as per Xu et al.,
(2008), Plant Biotechnology Journal. 6:799-818.
Upid profile
In a further embodiment the cell, cells, tissues, plants and plant parts of the invention have an
altered lipid profile relative to the control cells, tissues, plants and plant parts.
Those skilled in the art are well aware of methods for assessing lipid profile. This may involve
assessing the proportion or percentage of at least one of the 16:0, 16:1, 18:0, 18:lc9 fatty acid
species present in the lipid. This may typically be done by fatty acid methyl ester (FAME)
analysis (Browse et al., 1986, Anal. Biochem. 152, 141-145). Suitable methods are also described
in the examples section of this specification.
Cells
The chimeric DGAT1 of the invention, or as used in the methods of the invention, may be
expressed in any cell type.
In one embodiment the cell is a prokaryotic cell. In a further embodiment the cell is a eukaryotic
cell. In one embodiment the cell is selected from a bacterial cell, a yeast cell, a fungal cell, an
insect cell, algal cell, and a plant cell. In one embodiment the cell is a bacterial cell. In a further
embodiment the cell is a yeast cell. In one embodiment the yeast cell is a S . ceriviseae cell. In
further embodiment the cell is a fungal cell. In further embodiment the cell is an insect cell. In
further embodiment the cell is an algal cell. In a further embodiment the cell is a plant cell.
In one embodiment the cell is a non-plant cell. In one embodiment the non-plant is selected
from E . coli, P. pastoris, S . ceriviseae, D . salina and C. reinhardtii. In a further embodiment the nonplant
is selected from P. pastoris, S . ceriviseae, D . Salina and C. reinhardtii.
In one embodiment the cell is a microbial cell. In another embodiment, the microbial cell is an
algal cell of the division of Chlorophyta (green algae), Rhodophyta (red algae), Phaeophyceae
(brown algae), Bacillariophycaeae (diatoms), or Dinoflagellata (dinoflagellates). In another
embodiment, the microbial cell is an algal cell of the species Chlamydomonas, Dunaliella, Botrycoccus,
Chlorella, Crypthecodinium, Gracilaria, Sargassum, Pleurochrysis, Porphyridium, Phaeodactylum,
Haematococcus, Isochrysis, Scenedesmus, Monodus, Cyclotella, Nit^schia, or Parietochloris. In another
embodiment, the algal cell is Chlamydomonas reinhardtii. In yet another embodiment, the cell is
from the genus Yarrowia, Candida, Rhodotomla, Rhodosporidium, Cryptococcus, Trichosporon, Eipomyces,
Pythium, Thraustochytrium, or Ulkenia. In yet another embodiment, the cell is a
bacterium of the genus Rhodococcus, Escherichia, or a cyanobacterium. In yet another embodiment,
the cell is a yeast cell. In yet another embodiment, the cell is a synthetic cell.
Plants
The first and/ or second DGATl sequences, from which the chimeric DGATl sequences are
produced, may be naturally-occurring DGATl sequences. Preferably the first and/ or DGATl
sequences are from plants. In certain embodiments the cells into which the chimeric DGATl
proteins are expressed are from plants. In other embodiments the chimeric DGATl proteins
are expressed in plants.
The plant cells, from which the first and/ or second DGATl proteins are derived, the plants
from which the plant cells are derived, and the plants in which the chimeric DGATl proteins are
expressed may be from any plant species.
In one embodiment the plant cell or plant, is derived from a gymnosperm plant species.
In a further embodiment the plant cell or plant, is derived from an angiosperm plant species.
In a further embodiment the plant cell or plant, is derived from a from dicotyledonous plant
species.
In a further embodiment the plant cell or plant, is derived from a monocotyledonous plant
species.
Other preferred plants are forage plant species from a group comprising but not limited to the
following genera: Zea, Tolium, Hordium, Miscanthus, Saccharum, Festuca, Dactylis, Bromus, Thinopyrum,
Trifolium, Medicago, Pheleum, Phalaris, Holms, Gyl cine, L s, Plantago and Cichorium.
Other preferred plants are leguminous plants. The leguminous plant or part thereof may
encompass any plant in the plant family Leguminosae or Fabaceae. For example, the plants may
be selected from forage legumes including, alfalfa, clover; leucaena; grain legumes including,
beans, lentils, lupins, peas, peanuts, soy bean; bloom legumes including lupin, pharmaceutical or
industrial legumes; and fallow or green manure legume species.
A particularly preferred genus is Trifolium. Preferred Trifolium species include Trifolium repens;
Trifolium arvense; Trifolium affine; and Trifolium occidentak. A particularly preferred Trifolium species is
Trifolium repens.
Another preferred genus is Medicago. Preferred Medicago species include Medicago sativa and
Medicago truncatula. A particularly preferred Medicago species is Medicago sativa, commonly known
as alfalfa.
Another preferred genus is Gyl cine. Preferred Gyl cine species include Gyl cine max and Gyl cine wightii
(also known as Neonotonia wightii). A particularly preferred Gyl cine species is Gyl cine max,
commonly known as soy bean. A particularly preferred Gyl cine species is Gyl cine wightii,
commonly known as perennial soybean.
Another preferred genus is Vigna. A particularly preferred Vigna species is Vigna unguiculata
commonly known as cowpea.
Another preferred genus is Mucana. Preferred Mucana species include Mucana pruniens. A
particularly preferred Mucana species is Mucana pruniens commonly known as velvetbean.
Another preferred genus is Arachis. A particularly preferred Arachis species is Arachis glabrata
commonly known as perennial peanut.
Another preferred genus is Visum. A preferred Visum species is Visum sativum commonly known
as pea.
Another preferred genus is Lotus. Preferred Lotus species include Lotus comiculatus, Lotus
pedunculatus, Lotus glabar, Lotus tenuis and Lotus uliginosus. A preferred Lotus species is Lotus
comiculatus commonly known as Birdsfoot Trefoil. Another preferred Lotus species is Lotus glabar
commonly known as Narrow-leaf Birdsfoot Trefoil. Another preferred preferred Lotus species is
Lotus pedunculatus commonly known as Big trefoil. Another preferred Lotus species is Lotus tenuis
commonly known as Slender trefoil.
Another preferred genus is Brassica. A preferred Brassica species is Brassica oleracea, commonly
known as forage kale and cabbage. A preferred Brassica genus is Camelina. A preferred
Camelina species is Camelina sativa.
Other preferred species are oil seed crops including but not limited to the following genera:
Brassica, Carthumus, Helianthus, Zea and Sesamum.
A preferred oil seed genera is Brassica. A preferred oil seed species is Brassica napus.
A preferred oil seed genera is Brassica. A preferred oil seed species is Brassica oleraceae.
A preferred oil seed genera is Carthamus. A preferred oil seed species is Carthamus tinctorius.
A preferred oil seed genera is Helianthus. A preferred oil seed species is Helianthus annuus.
A preferred oil seed genera is Zea. A preferred oil seed species is Zea mays.
A preferred oil seed genera is Sesamum. A preferred oil seed species is Sesamum indkum.
A preferred silage genera is Zea. A preferred silage species is Zea mays.
A preferred grain producing genera is Hordeum. A preferred grain producing species is Hordeum
vulgare.
A preferred grazing genera is olium. A preferred grazing species is oliumperenne.
A preferred grazing genera is Lolium. A preferred grazing species is Lolium arundinaceum.
A preferred grazing genera is Trifolium. A preferred grazing species is Trifolium repens.
A preferred grazing genera is Hordeum. A preferred grazing species is Hordeum vulgare.
Preferred plants also include forage, or animal feedstock plants. Such plants include but are not
limited to the following genera: Miscanthus, Saccharum, Pankum.
A preferred biofuel genera is Miscanthus. A preferred biofuel species is Miscanthus giganteus.
A preferred biofuel genera is Saccharum. A preferred biofuel species is Saccharum ojficinarum.
A preferred biofuel genera is Pankum. A preferred biofuel speices is Pankum virgatum.
Plant parts, propagues and progeny
The term "plant" is intended to include a whole plant, any part of a plant, a seed, a fruit,
propagules and progeny of a plant.
The term 'propagule' means any part of a plant that may be used in reproduction or propagation,
either sexual or asexual, including seeds and cuttings.
The plants of the invention may be grown and either self-ed or crossed with a different plant
strain and the resulting progeny, comprising the polynucleotides or constructs of the invention,
and/or expressing the chimeric DGATl sequences of the invention, also form an part of the
present invention.
Preferably the plants, plant parts, propagules and progeny comprise a polynucleotide or
construct of the invention, and/ or express a chimeric DGATl sequence of the invention.
Poyl nucleotides and fragments
The term "polynucleotide(s)," as used herein, means a single or double-stranded
deoxyribonucleotide or ribonucleotide polymer of any length but preferably at least 15
nucleotides, and include as non-limiting examples, coding and non-coding sequences of a gene,
sense and antisense sequences complements, exons, introns, genomic DNA, cDNA, pre-mRNA,
mRNA, rRNA, siRNA, miRNA, tRNA, ribozymes, recombinant polypeptides, isolated and
purified naturally occurring DNA or RNA sequences, synthetic RNA and DNA sequences,
nucleic acid probes, primers and fragments.
A "fragment" of a polynucleotide sequence provided herein is a subsequence of contiguous
nucleotides.
The term "primer" refers to a short polynucleotide, usually having a free 3Ό H group, that is
hybridized to a template and used for priming polymerization of a polynucleotide
complementary to the target.
The term "probe" refers to a short polynucleotide that is used to detect a polynucleotide
sequence that is complementary to the probe, in a hybridization-based assay. The probe may
consist of a "fragment" of a polynucleotide as defined herein.
Poylpeptides and fragments
The term "polypeptide", as used herein, encompasses amino acid chains of any length but
preferably at least 5 amino acids, including full-length proteins, in which amino acid residues are
linked by covalent peptide bonds. Polypeptides of the present invention, or used in the methods
of the invention, may be purified natural products, or may be produced partially or wholly using
recombinant or synthetic techniques.
A "fragment" of a polypeptide is a subsequence of the polypeptide that preferably performs a
function of and/ or provides three dimensional structure of the polypeptide. The term may refer
to a polypeptide, an aggregate of a polypeptide such as a dimer or other multimer, a fusion
polypeptide, a polypeptide fragment, a polypeptide variant, or derivative thereof capable of
performing the above enzymatic activity.
The term "isolated" as applied to the polynucleotide or polypeptide sequences disclosed herein is
used to refer to sequences that are removed from their natural cellular environment. An isolated
molecule may be obtained by any method or combination of methods including biochemical,
recombinant, and synthetic techniques.
The term "recombinant" refers to a polynucleotide sequence that is removed from sequences
that surround it in its natural context and/ or is recombined with sequences that are not present
in its natural context.
A "recombinant" polypeptide sequence is produced by translation from a "recombinant"
polynucleotide sequence.
The term "derived from" with respect to polynucleotides or polypeptides of the invention being
derived from a particular genera or species, means that the polynucleotide or polypeptide has the
same sequence as a polynucleotide or polypeptide found naturally in that genera or species. The
polynucleotide or polypeptide, derived from a particular genera or species, may therefore be
produced synthetically or recombinantly.
Variants
As used herein, the term "variant" refers to polynucleotide or polypeptide sequences different
from the specifically identified sequences, wherein one or more nucleotides or amino acid
residues is deleted, substituted, or added. Variants may be naturally occurring allelic variants, or
non-naturally occurring variants. Variants may be from the same or from other species and may
encompass homologues, paralogues and orthologues. In certain embodiments, variants of the
inventive polypeptides and polypeptides possess biological activities that are the same or similar
to those of the inventive polypeptides or polypeptides. The term "variant" with reference to
polypeptides and polypeptides encompasses all forms of polypeptides and polypeptides as
defined herein.
Poyl nucleotide variants
Variant polynucleotide sequences preferably exhibit at least 50%, more preferably at least 51%,
more preferably at least 52%, more preferably at least 53%, more preferably at least 54%, more
preferably at least 55%, more preferably at least 56%, more preferably at least 57%, more
preferably at least 58%, more preferably at least 59%, more preferably at least 60%, more
preferably at least 61%, more preferably at least 62%, more preferably at least 63%, more
preferably at least 64%, more preferably at least 65%, more preferably at least 66%, more
preferably at least 67%, more preferably at least 68%, more preferably at least 69%, more
preferably at least 70%, more preferably at least 71%, more preferably at least 72%, more
preferably at least 73%, more preferably at least 74%, more preferably at least 75%, more
preferably at least 76%, more preferably at least 77%, more preferably at least 78%, more
preferably at least 79%, more preferably at least 80%, more preferably at least 81%, more
preferably at least 82%, more preferably at least 83%, more preferably at least 84%, more
preferably at least 85%, more preferably at least 86%, more preferably at least 87%, more
preferably at least 88%, more preferably at least 89%, more preferably at least 90%, more
preferably at least 91%, more preferably at least 92%, more preferably at least 93%, more
preferably at least 94%, more preferably at least 95%, more preferably at least 96%, more
preferably at least 97%, more preferably at least 98%, and most preferably at least 99% identity
to a sequence of the present invention. Identity is found over a comparison window of at least
20 nucleotide positions, preferably at least 50 nucleotide positions, more preferably at least 100
nucleotide positions, and most preferably over the entire length of a polynucleotide of the
invention.
Polynucleotide sequence identity can be determined in the following manner. The subject
polynucleotide sequence is compared to a candidate polynucleotide sequence using BLASTN
(from the BLAST suite of programs, version 2.2.5 [Nov 2002]) in bl2seq (Tatiana A. Tatusova,
Thomas L. Madden (1999), "Blast 2 sequences - a new tool for comparing protein and
nucleotide sequences", FEMS Microbiol Lett. 174:247-250), which is publicly available from the
NCBI website on the World Wide Web at ftp:/ / ftp.ncbi.nih.gov/blast/. The default parameters
of bl2seq are utilized except that filtering of low complexity parts should be turned off.
The identity of polynucleotide sequences may be examined using the following unix command
line parameters:
bl2seq - i nucleotideseql —nucleotideseq2 - F F — blastn
The parameter —F F turns off filtering of low complexity sections. The parameter —p selects the
appropriate algorithm for the pair of sequences. The bl2seq program reports sequence identity
as both the number and percentage of identical nucleotides in a line "Identities = " .
Polynucleotide sequence identity may also be calculated over the entire length of the overlap
between a candidate and subject polynucleotide sequences using global sequence alignment
programs (e.g. Needleman, S. B. and Wunsch, C. D . (1970) J . Mol. Biol. 48, 443-453). A full
implementation of the Needleman-Wunsch global alignment algorithm is found in the needle
program in the EMBOSS package (Rice,P. Longden,I. and Bleasby,A. EMBOSS: The European
Molecular Biology Open Software Suite, Trends in Genetics June 2000, vol 16, No 6. pp.276-
277) which can be obtained from the World Wide Web at
http://www.hgmp.mrc.ac.uk/Software/EMBOSS/. The European Bioinformatics Institute
server also provides the facility to perform EMBOSS-needle global alignments between two
sequences on line at http:/www.ebi.ac.uk/ emboss/ align/.
Alternatively the GAP program may be used which computes an optimal global alignment of
two sequences without penalizing terminal gaps. GAP is described in the following paper:
Huang, X. (1994) On Global Sequence Alignment. Computer Applications in the Biosciences 10,
227-235.
A preferred method for calculating polynucleotide % sequence identity is based on aligning
sequences to be compared using Clustal X (Jeanmougin et al., 1998, Trends Biochem. Sci. 23,
403-5.)
Polynucleotide variants of the present invention also encompass those which exhibit a similarity
to one or more of the specifically identified sequences that is likely to preserve the functional
equivalence of those sequences and which could not reasonably be expected to have occurred by
random chance. Such sequence similarity with respect to polypeptides may be determined using
the publicly available bl2seq program from the BLAST suite of programs (version 2.2.5 [Nov
2002]) from the NCBI website on the World Wide Web at ftp:/ / ftp.ncbi.nih.gov/blast/.
The similarity of polynucleotide sequences may be examined using the following unix command
line parameters:
bl2seq - i nucleotideseql —nucleotideseq2 - F F — tblastx
The parameter —F F turns off filtering of low complexity sections. The parameter —p selects the
appropriate algorithm for the pair of sequences. This program finds regions of similarity between
the sequences and for each such region reports an "E value" which is the expected number of
times one could expect to see such a match by chance in a database of a fixed reference size
containing random sequences. The size of this database is set by default in the bl2seq program.
For small E values, much less than one, the E value is approximately the probability of such a
random match.
Variant polynucleotide sequences preferably exhibit an E value of less than 1 x 10 -6 more
preferably less than 1 x 10 -9, more preferably less than 1 x 0 -12, more preferably less than 1 x
10 -15, more preferably less than x 0 -18, more preferably less than x 0 -21, more
preferably less than x 0 -30, more preferably less than x 0 -40, more preferably less than
x 0 -50, more preferably less than x 0 -60, more preferably less than x 0 -70, more
preferably less than x 0 -80, more preferably less than x 0 -90 and most preferably less
than 1 x 10-100 when compared with any one of the specifically identified sequences.
Alternatively, variant polynucleotides of the present invention, or used in the methods of the
invention, hybridize to the specified polynucleotide sequences, or complements thereof under
stringent conditions.
The term "hybridize under stringent conditions", and grammatical equivalents thereof, refers to
the ability of a polynucleotide molecule to hybridize to a target polynucleotide molecule (such as
a target polynucleotide molecule immobilized on a DNA or RNA blot, such as a Southern blot
or Northern blot) under defined conditions of temperature and salt concentration. The ability to
hybridize under stringent hybridization conditions can be determined by initially hybridizing
under less stringent conditions then increasing the stringency to the desired stringency.
With respect to polynucleotide molecules greater than about 100 bases in length, typical stringent
hybridization conditions are no more than 25 to 30° C (for example, 10° C) below the melting
temperature (Tm) of the native duplex (see generally, Sambrook et al, Eds, 1987, Molecular
Cloning, A Laboratory Manual, 2nd Ed. Cold Spring Harbor Press; Ausubel et al, 1987, Current
Protocols in Molecular Biology, Greene Publishing,). Tm for polynucleotide molecules greater
than about 00 bases can be calculated by the formula Tm = 81. 5 + 0. 41% (G + C-log (Na+).
(Sambrook et al, Eds, 1987, Molecular Cloning, A Laboratory Manual, 2nd Ed. Cold Spring
Harbor Press; Bolton and McCarthy, 1962, PNAS 84:1390). Typical stringent conditions for
polynucleotide of greater than 100 bases in length would be hybridization conditions such as
prewashing in a solution of 6X SSC, 0.2% SDS; hybridizing at 65°C, 6X SSC, 0.2% SDS
overnight; followed by two washes of 30 minutes each in X SSC, 0.1% SDS at 65° C and two
washes of 30 minutes each in 0.2X SSC, 0.1% SDS at 65°C.
With respect to polynucleotide molecules having a length less than 100 bases, exemplary
stringent hybridization conditions are 5 to 10° C below Tm. On average, the Tm of a
polynucleotide molecule of length less than 100 bp is reduced by approximately
(500/oligonucleotide length) C.
With respect to the DNA mimics known as peptide nucleic acids (PNAs) (Nielsen et al, Science.
1991 Dec 6;254(5037):1497-500) Tm values are higher than those for DNA-DNA or DNARNA
hybrids, and can be calculated using the formula described in Giesen et al, Nucleic Acids
Res. 1998 Nov l;26(21):5004-6. Exemplary stringent hybridization conditions for a DNA-PNA
hybrid having a length less than 100 bases are 5 to 10° C below the Tm.
Variant polynucleotides of the present invention, or used in the methods of the invention, also
encompasses polynucleotides that differ from the sequences of the invention but that, as a
consequence of the degeneracy of the genetic code, encode a polypeptide having similar activity
to a polypeptide encoded by a polynucleotide of the present invention. A sequence alteration
that does not change the amino acid sequence of the polypeptide is a "silent variation". Except
for ATG (methionine) and TGG (tryptophan), other codons for the same amino acid may be
changed by art recognized techniques, e.g., to optimize codon expression in a particular host
organism.
Polynucleotide sequence alterations resulting in conservative substitutions of one or several
amino acids in the encoded polypeptide sequence without significantly altering its biological
activity are also included in the invention. A skilled artisan will be aware of methods for making
phenotypically silent amino acid substitutions (see, e.g., Bowie et al, 1990, Science 247, 1306).
Variant polynucleotides due to silent variations and conservative substitutions in the encoded
polypeptide sequence may be determined using the publicly available bl2seq program from the
BLAST suite of programs (version 2.2.5 [Nov 2002]) from the NCBI website on the World Wide
Web at ftp:/ / ftp.ncbi.nih.gov/blast/ via the tblastx algorithm as previously described.
Poylpeptide variants
The term "variant" with reference to polypeptides encompasses naturally occurring,
recombinantly and synthetically produced polypeptides. Variant polypeptide sequences
preferably exhibit at least 50%, more preferably at least 51%, more preferably at least 52%, more
preferably at least 53%, more preferably at least 54%, more preferably at least 55%, more
preferably at least 56%, more preferably at least 57%, more preferably at least 58%, more
preferably at least 59%, more preferably at least 60%, more preferably at least 61%, more
preferably at least 62%, more preferably at least 63%, more preferably at least 64%, more
preferably at least 65%, more preferably at least 66%, more preferably at least 67%, more
preferably at least 68%, more preferably at least 69%, more preferably at least 70%, more
preferably at least 71%, more preferably at least 72%, more preferably at least 73%, more
preferably at least 74%, more preferably at least 75%, more preferably at least 76%, more
preferably at least 77%, more preferably at least 78%, more preferably at least 79%, more
preferably at least 80%, more preferably at least 81%, more preferably at least 82%, more
preferably at least 83%, more preferably at least 84%, more preferably at least 85%, more
preferably at least 86%, more preferably at least 87%, more preferably at least 88%, more
preferably at least 89%, more preferably at least 90%, more preferably at least 91%, more
preferably at least 92%, more preferably at least 93%, more preferably at least 94%, more
preferably at least 95%, more preferably at least 96%, more preferably at least 97%, more
preferably at least 98%, and most preferably at least 99% identity to a sequences of the present
invention. Identity is found over a comparison window of at least 20 amino acid positions,
preferably at least 50 amino acid positions, more preferably at least 100 amino acid positions, and
most preferably over the entire length of a polypeptide of the invention.
Polypeptide sequence identity can be determined in the following manner. The subject
polypeptide sequence is compared to a candidate polypeptide sequence using BLASTP (from the
BLAST suite of programs, version 2.2.5 [Nov 2002]) in bl2seq, which is publicly available from
the NCBI website on the World Wide Web at ftp://ftp.ncbi.nih.gov/blast/. The default
parameters of bl2seq are utilized except that filtering of low complexity regions should be turned
off.
Polypeptide sequence identity may also be calculated over the entire length of the overlap
between a candidate and subject polynucleotide sequences using global sequence alignment
programs. EMBOSS-needle (available at http:/www.ebi.ac.uk/emboss/align/) and GAP
(Huang, X. (1994) On Global Sequence Alignment. Computer Applications in the Biosciences
10, 227-235.) as discussed above are also suitable global sequence alignment programs for
calculating polypeptide sequence identity.
A preferred method for calculating polypeptide % sequence identity is based on aligning
sequences to be compared using Clustal X (Jeanmougin et al., 1998, Trends Biochem. Sci. 23,
403-5.)
Polypeptide variants of the present invention, or used in the methods of the invention, also
encompass those which exhibit a similarity to one or more of the specifically identified
sequences that is likely to preserve the functional equivalence of those sequences and which
could not reasonably be expected to have occurred by random chance. Such sequence similarity
with respect to polypeptides may be determined using the publicly available bl2seq program
from the BLAST suite of programs (version 2.2.5 [Nov 2002]) from the NCBI website on the
World Wide Web at ftp:/ / ftp.ncbi.nih.gov/blast/. The similarity of polypeptide sequences may
be examined using the following unix command line parameters:
bl2seq - i peptideseql - j peptideseq2 -F F - p blastp
Variant polypeptide sequences preferably exhibit an E value of less than 1 x 10 -6 more
preferably less than 1 x 10 -9, more preferably less than 1 x 0 -12, more preferably less than 1 x
10 -15, more preferably less than x 0 -18, more preferably less than x 0 -21, more
preferably less than x 0 -30, more preferably less than x 0 -40, more preferably less than 1
x 10 -50, more preferably less than x 0 -60, more preferably less than x 0 -70, more
preferably less than x 0 -80, more preferably less than x 0 -90 and most preferably 1x10-
00 when compared with any one of the specifically identified sequences.
The parameter —F F turns off filtering of low complexity sections. The parameter —p selects the
appropriate algorithm for the pair of sequences. This program finds regions of similarity between
the sequences and for each such region reports an "E value" which is the expected number of
times one could expect to see such a match by chance in a database of a fixed reference size
containing random sequences. For small E values, much less than one, this is approximately the
probability of such a random match.
Conservative substitutions of one or several amino acids of a described polypeptide sequence
without significantly altering its biological activity are also included in the invention. A skilled
artisan will be aware of methods for making phenotypically silent amino acid substitutions (see,
e.g., Bowie et al., 1990, Science 247, 1306).
Constructs, vectors and components thereof
The term "genetic construct" refers to a polynucleotide molecule, usually double-stranded DNA,
which may have inserted into it another polynucleotide molecule (the insert polynucleotide
molecule) such as, but not limited to, a cDNA molecule. A genetic construct may contain the
necessary elements that permit transcribing the insert polynucleotide molecule, and, optionally,
translating the transcript into a polypeptide. The insert polynucleotide molecule may be derived
from the host cell, or may be derived from a different cell or organism and/or may be a
recombinant polynucleotide. Once inside the host cell the genetic construct may become
integrated in the host chromosomal DNA. The genetic construct may be linked to a vector.
The term "vector" refers to a polynucleotide molecule, usually double stranded DNA, which is
used to transport the genetic construct into a host cell. The vector may be capable of replication
in at least one additional host system, such as E . coli.
The term "expression construct" refers to a genetic construct that includes the necessary
elements that permit transcribing the insert polynucleotide molecule, and, optionally, translating
the transcript into a polypeptide. An expression construct typically comprises in a 5' to 3'
direction:
a) a promoter functional in the host cell into which the construct will be
transformed,
b) the polynucleotide to be expressed, and
c) a terminator functional in the host cell into which the construct will be
transformed.
The term "coding region" or "open reading frame" (ORF) refers to the sense strand of a
genomic DNA sequence or a cDNA sequence that is capable of producing a transcription
product and/or a polypeptide under the control of appropriate regulatory sequences. The
coding sequence may, in some cases, identified by the presence of a 5' translation start codon
and a 3' translation stop codon. When inserted into a genetic construct, a "coding sequence" is
capable of being expressed when it is operably linked to promoter and terminator sequences.
"Operably-linked" means that the sequenced to be expressed is placed under the control of
regulatory elements that include promoters, tissue-specific regulatory elements, temporal
regulatory elements, enhancers, repressors and terminators.
The term "noncoding region" refers to untranslated sequences that are upstream of the
translational start site and downstream of the translational stop site. These sequences are also
referred to respectively as the 5' UTR and the 3' UTR. These regions include elements required
for transcription initiation and termination, mRNA stability, and for regulation of translation
efficiency.
Terminators are sequences, which terminate transcription, and are found in the 3' untranslated
ends of genes downstream of the translated sequence. Terminators are important determinants
of mRNA stability and in some cases have been found to have spatial regulatory functions.
The term "promoter" refers to nontranscribed cis -regulatory elements upstream of the coding
region that regulate gene transcription. Promoters comprise cis-initiator elements which specify
the transcription initiation site and conserved boxes such as the TATA box, and motifs that are
bound by transcription factors. Introns within coding sequences can also regulate transcription
and influence post- transcriptional processing (including splicing, capping and polyadenylation).
A promoter may be homologous with respect to the polynucleotide to be expressed. This means
that the promoter and polynucleotide are found operably linked in nature.
Alternatively the promoter may be heterologous with respect to the polynucleotide to be
expressed. This means that the promoter and the polynucleotide are not found operably linked
in nature.
In certain embodiments the chimeric DGATl polynucleotides/polypeptides of the invention
may be andvantageously expessed under the contol of selected promoter sequences as described
below.
Vegetative tissue specificpromoters
An example of a vegetative specific promoter is found in US 6,229,067; and US 7,629,454; and
US 7,153,953; and US 6,228,643.
Pollen specificpromoters
An example of a pollen specific promoter is found in US 7,141,424; and US 5,545,546; and US
5,412,085; and US 5,086,169; and US 7,667,097.
Seed specificpromoters
An example of a seed specific promoter is found in US 6,342,657; and US 7,081,565; and US
7,405,345; and US 7,642,346; and US 7,371,928. A preferred seed specific promoter is the napin
promoter of Brassica napus (Josefsson et al., 1987, J Biol Chem. 262(25):12196-201; Ellerstrom et
al., 1996, Plant Molecular Biology, Volume 32, Issue 6, pp 1019-1027).
Fruit specificpromoters
An example of a fruit specific promoter is found in US 5,536,653; and US 6,127,179; and US
5,608,150; and US 4,943,674.
Non-photosynthetic tissuepreferredpromoters
Non-photosynthetic tissue preferred promoters include those preferentially expressed in nonphotosynfhetic
tissues/ organs of the plant.
Non-photosynthetic tissue preferred promoters may also include light repressed promoters.
ght repressedpromoters
An example of a light repressed promoter is found in US 5,639,952 and in US 5,656,496.
Root specificpromoters
An example of a root specific promoter is found in US 5,837,848; and US 2004/ 0067506 and US
2001/0047525.
Tuber specificpromoters
An example of a tuber specific promoter is found in US 6,184,443.
Bulb specificpromoters
An example of a bulb specific promoter is found in Smeets et al., (1997) Plant Physiol. 113:765-
771.
Rhizome preferredpromoters
An example of a rhizome preferred promoter is found Seongjang et al., (2006) Plant Physiol.
142:1148-1159.
Endosperm specificpromoters
An example of an endosperm specific promoter is found in US 7,745,697.
Cormpromoters
An example of a promoter capable of driving expression in a corm is found in Schenk et al,
(2001) Plant Molecular Biology, 47:399-412.
Photosythetic tissuepreferred promoters
Photosythetic tissue preferred promoters include those that are preferentially expressed in
photosynthetic tissues of the plants. Photosynthetic tissues of the plant include leaves, stems,
shoots and above ground parts of the plant. Photosythetic tissue preferred promoters include
light regulated promoters.
Light regulatedpromoters
Numerous light regulated promoters are known to those skilled in the art and include for
example chlorophyll a/b (Cab) binding protein promoters and Rubisco Small Subunit (SSU)
promoters. An example of a light regulated promoter is found in US 5,750,385. Light regulated
in this context means light inducible or light induced.
A "transgene" is a polynucleotide that is taken from one organism and introduced into a
different organism by transformation. The transgene may be derived from the same species or
from a different species as the species of the organism into which the transgene is introduced.
Host cells
Host cells may be derived from, for example, bacterial, fungal, yeast, insect, mammalian, algal or
plant organisms. Host cells may also be synthetic cells. Preferred host cells are eukaryotic cells.
A particularly preferred host cell is a plant cell, particularly a plant cell in a vegetative tissue of a
plant.
A "transgenic plant" refers to a plant which contains new genetic material as a result of genetic
manipulation or transformation. The new genetic material may be derived from a plant of the
same species as the resulting transgenic plant or from a different species.
Methods for isolating orproducing poyl nucleotides
The polynucleotide molecules of the invention can be isolated by using a variety of techniques
known to those of ordinary skill in the art. By way of example, such polypeptides can be isolated
through use of the polymerase chain reaction (PCR) described in Mullis et al., Eds. 1994 The
Polymerase Chain Reaction, Birkhauser, incorporated herein by reference. The polypeptides of
the invention can be amplified using primers, as defined herein, derived from the polynucleotide
sequences of the invention.
Further methods for isolating polynucleotides of the invention include use of all, or portions of,
the polypeptides having the sequence set forth herein as hybridization probes. The technique of
hybridizing labelled polynucleotide probes to polynucleotides immobilized on solid supports
such as nitrocellulose filters or nylon membranes, can be used to screen the genomic or cDNA
libraries. Exemplary hybridization and wash conditions are: hybridization for 20 hours at 65°C
in 5. 0 X SSC, 0. 5% sodium dodecyl sulfate, 1 X Denhardt's solution; washing (three washes of
twenty minutes each at 55°C) in 1. 0 X SSC, 1% (w/v) sodium dodecyl sulfate, and optionally
one wash (for twenty minutes) in 0. 5 X SSC, 1% (w/v) sodium dodecyl sulfate, at 60°C. An
optional further wash (for twenty minutes) can be conducted under conditions of 0.1 X SSC, 1%
(w/v) sodium dodecyl sulfate, at 60°C.
The polynucleotide fragments of the invention may be produced by techniques well-known in
the art such as restriction endonuclease digestion, oligonucleotide synthesis and PCR
amplification.
A partial polynucleotide sequence may be used, in methods well-known in the art to identify the
corresponding full length polynucleotide sequence. Such methods include PCR-based methods,
5'RACE (Frohman MA, 1993, Methods Enzymol. 218: 340-56) and hybridization- based
method, computer/ database -based methods. Further, by way of example, inverse PCR permits
acquisition of unknown sequences, flanking the polynucleotide sequences disclosed herein,
starting with primers based on a known region (Triglia et al, 1998, Nucleic Acids Res 16, 8186,
incorporated herein by reference). The method uses several restriction enzymes to generate a
suitable fragment in the known region of a gene. The fragment is then circularized by
intramolecular ligation and used as a PCR template. Divergent primers are designed from the
known region. In order to physically assemble full-length clones, standard molecular biology
approaches can be utilized (Sambrook et al., Molecular Cloning: A Laboratory Manual, 2nd Ed.
Cold Spring Harbor Press, 1987).
It may be beneficial, when producing a transgenic plant from a particular species, to transform
such a plant with a sequence or sequences derived from that species. The benefit may be to
alleviate public concerns regarding cross-species transformation in generating transgenic
organisms. For these reasons among others, it is desirable to be able to identify and isolate
orfhologues of a particular gene in several different plant species.
Variants (including orthologues) may be identified by the methods described.
Methods for identifying variants
Physical methods
Variant polypeptides may be identified using PCR-based methods (Mullis et al, Eds. 1994 The
Polymerase Chain Reaction, Birkhauser). Typically, the polynucleotide sequence of a primer,
useful to amplify variants of polynucleotide molecules of the invention by PCR, may be based on
a sequence encoding a conserved region of the corresponding amino acid sequence.
Alternatively library screening methods, well known to those skilled in the art, may be employed
(Sambrook et al, Molecular Cloning: A Laboratory Manual, 2nd Ed. Cold Spring Harbor Press,
1987). When identifying variants of the probe sequence, hybridization and/ or wash stringency
will typically be reduced relatively to when exact sequence matches are sought.
Polypeptide variants may also be identified by physical methods, for example by screening
expression libraries using antibodies raised against polypeptides of the invention (Sambrook et al,
Molecular Cloning: A Laboratory Manual, 2nd Ed. Cold Spring Harbor Press, 1987) or by
identifying polypeptides from natural sources with the aid of such antibodies.
Computer based methods
The variant sequences of the invention, including both polynucleotide and polypeptide variants,
may also be identified by computer-based methods well-known to those skilled in the art, using
public domain sequence alignment algorithms and sequence similarity search tools to search
sequence databases (public domain databases include Genbank, EMBL, Swiss-Prot, PIR and
others). See, e.g., Nucleic Acids Res. 29: 1-10 and 11-16, 2001 for examples of online resources.
Similarity searches retrieve and align target sequences for comparison with a sequence to be
analyzed (i.e., a query sequence). Sequence comparison algorithms use scoring matrices to assign
an overall score to each of the alignments.
An exemplary family of programs useful for identifying variants in sequence databases is the
BLAST suite of programs (version 2.2.5 [Nov 2002]) including BLASTN, BLASTP, BLASTX,
tBLASTN and tBLASTX, which are publicly available from (ftp://ftp.ncbi.nih.gov/blast/) or
from the National Center for Biotechnology Information (NCBI), National Library of Medicine,
BuHding 38A, Room 8N805, Bethesda, MD 20894 USA. The NCBI server also provides the
facility to use the programs to screen a number of publicly available sequence databases.
BLASTN compares a nucleotide query sequence against a nucleotide sequence database.
BLASTP compares an amino acid query sequence against a protein sequence database.
BLASTX compares a nucleotide query sequence translated in all reading frames against a protein
sequence database. tBLASTN compares a protein query sequence against a nucleotide sequence
database dynamically translated in all reading frames. tBLASTX compares the six-frame
translations of a nucleotide query sequence against the six-frame translations of a nucleotide
sequence database. The BLAST programs may be used with default parameters or the
parameters may be altered as required to refine the screen.
The use of the BLAST family of algorithms, including BLASTN, BLASTP, and BLASTX, is
described in the publication of Altschul et al., Nucleic Acids Res. 25: 3389-3402, 1997.
The "hits" to one or more database sequences by a queried sequence produced by BLASTN,
BLASTP, BLASTX, tBLASTN, tBLASTX, or a similar algorithm, align and identify similar
portions of sequences. The hits are arranged in order of the degree of similarity and the length
of sequence overlap. Hits to a database sequence generally represent an overlap over only a
fraction of the sequence length of the queried sequence.
The BLASTN, BLASTP, BLASTX, tBLASTN and tBLASTX algorithms also produce "Expect"
values for alignments. The Expect value (E) indicates the number of hits one can "expect" to see
by chance when searching a database of the same size containing random contiguous sequences.
The Expect value is used as a significance threshold for determining whether the hit to a
database indicates true similarity. For example, an E value of 0.1 assigned to a polynucleotide hit
is interpreted as meaning that in a database of the size of the database screened, one might
expect to see 0.1 matches over the aligned portion of the sequence with a similar score simply by
chance. For sequences having an E value of 0.01 or less over aligned and matched portions, the
probability of finding a match by chance in that database is 1% or less using the BLASTN,
BLASTP, BLASTX, tBLASTN or tBLASTX algorithm.
Multiple sequence alignments of a group of related sequences can be carried out with
CLUSTALW (Thompson, J.D., Higgins, D.G. and Gibson, T.J. (1994) CLUSTALW: improving
the sensitivity of progressive multiple sequence alignment through sequence weighting,
positions-specific gap penalties and weight matrix choice. Nucleic Acids Research, 22:4673-4680,
http:/ /www-igbmc.u-strasbg.fr/BioInfo/ClustalW/Top.html) or T-COFFEE (Cedric
Notredame, Desmond G. Higgins, Jaap Heringa, T-Coffee: A novel method for fast and
accurate multiple sequence alignment, J . Mol. Biol. (2000) 302: 205-217)) or PILEUP, which uses
progressive, pairwise alignments. (Feng and Doolittle, 1987, J . Mol. Evol. 25, 351).
Pattern recognition software applications are available for finding motifs or signature sequences.
For example, MEME (Multiple Em for Motif Elicitation) finds motifs and signature sequences in
a set of sequences, and MAST (Motif Alignment and Search Tool) uses these motifs to identify
similar or the same motifs in query sequences. The MAST results are provided as a series of
alignments with appropriate statistical data and a visual overview of the motifs found. MEME
and MAST were developed at the University of California, San Diego.
PROSITE (Bairoch and Bucher, 1994, Nucleic Acids Res. 22, 3583; Hofmann et al, 1999,
Nucleic Acids Res. 27, 215) is a method of identifying the functions of uncharacterized proteins
translated from genomic or cDNA sequences. The PROSITE database
(www.expasy.org/prosite) contains biologically significant patterns and profiles and is designed
so that it can be used with appropriate computational tools to assign a new sequence to a known
family of proteins or to determine which known domain(s) are present in the sequence (Falquet
et al, 2002, Nucleic Acids Res. 30, 235). Prosearch is a tool that can search SWISS-PROT and
EMBL databases with a given sequence pattern or signature.
Methods for isolatingpoylpeptides
The polypeptides of the invention, or used in the methods of the invention, including variant
polypeptides, may be prepared using peptide synthesis methods well known in the art such as
direct peptide synthesis using solid phase techniques (e.g. Stewart et al., 1969, in Solid-Phase
Peptide Synthesis, WH Freeman Co, San Francisco California, or automated synthesis, for
example using an Applied Biosystems 431A Peptide Synthesizer (Foster City, California).
Mutated forms of the polypeptides may also be produced during such syntheses.
The polypeptides and variant polypeptides of the invention, or used in the methods of the
invention, may also be purified from natural sources using a variety of techniques that are well
known in the art (e.g. Deutscher, 1990, Ed, Methods in Enzymology, Vol. 182, Guide to Protein
Purification,).
Alternatively the polypeptides and variant polypeptides of the invention, or used in the methods
of the invention, may be expressed recombinantly in suitable host cells and separated from the
cells as discussed below.
Methods for producing constructs and vectors
The genetic constructs of the present invention comprise one or more polynucleotide sequences
of the invention and/ or polynucleotides encoding polypeptides of the invention, and may be
useful for transforming, for example, bacterial, fungal, insect, mammalian or plant organisms.
The genetic constructs of the invention are intended to include expression constructs as herein
defined.
Methods for producing and using genetic constructs and vectors are well known in the art and
are described generally in Sambrook et al, Molecular Cloning: A Laboratory Manual, 2nd Ed.
Cold Spring Harbor Press, 1987 ; Ausubel et al, Current Protocols in Molecular Biology, Greene
Publishing, 1987).
Methods for producing host cells comprisingpoyl nucleotides, constructs or vectors
The invention provides a host cell which comprises a genetic construct or vector of the
invention.
Host cells comprising genetic constructs, such as expression constructs, of the invention are
useful in methods well known in the art (e.g. Sambrook et al, Molecular Cloning : A Laboratory
Manual, 2nd Ed. Cold Spring Harbor Press, 1987 ; Ausubel et al, Current Protocols in Molecular
Biology, Greene Publishing, 1987) for recombinant production of polypeptides of the invention.
Such methods may involve the culture of host cells in an appropriate medium in conditions
suitable for or conducive to expression of a polypeptide of the invention. The expressed
recombinant polypeptide, which may optionally be secreted into the culture, may then be
separated from the medium, host cells or culture medium by methods well known in the art (e.g.
Deutscher, Ed, 1990, Methods in Enzymology, Vol 182, Guide to Protein Purification).
Methods for producing plant cells and plants comprising constructs and vectors
The invention further provides plant cells which comprise a genetic construct of the invention,
and plant cells modified to alter expression of a polynucleotide or polypeptide of the invention,
or used in the methods of the invention. Plants comprising such cells also form an aspect of the
invention.
Methods for transforming plant cells, plants and portions thereof with polypeptides are
described in Draper et al, 1988, Plant Genetic Transformation and Gene Expression. A
Laboratory Manual Blackwell Sci. Pub. Oxford, p . 365; Potrykus and Spangenburg, 1995, Gene
Transfer to Plants. Springer- Verlag, Berlin.; and Gelvin et al, 1993, Plant Molecular Biol.
Manual. Kluwer Acad. Pub. Dordrecht. A review of transgenic plants, including transformation
techniques, is provided in Galun and Breiman, 1997, Transgenic Plants. Imperial College Press,
London.
Methods for genetic manipulation of plants
A number of plant transformation strategies are available (e.g. Birch, 1997, Ann Rev Plant Phys
Plant Mol Biol, 48, 297, HeUens RP, et al, (2000) Plant Mol Biol 42: 819-32, HeUens R et al,
Plant Meth 1: 13). For example, strategies may be designed to increase expression of a
polynucleotide/polypeptide in a plant ceU, organ and/or at a particular developmental stage
where/when it is normaUy expressed or to ectopicaUy express a polynucleotide/polypeptide in a
ceU, tissue, organ and/or at a particular developmental stage which/when it is not normaUy
expressed. The expressed polynucleotide/ polypeptide may be derived from the plant species to
be transformed or may be derived from a different plant species.
Transformation strategies may be designed to reduce expression of a polynucleotide/polypeptide
in a plant ceU, tissue, organ or at a particular developmental stage which/when it is normaUy
expressed. Such strategies are known as gene sUencing strategies.
Genetic constructs for expression of genes in transgenic plants typicaUy include promoters for
driving the expression of one or more cloned polynucleotide, terminators and selectable marker
sequences to detect presence of the genetic construct in the transformed plant.
The promoters suitable for use in the constructs of this invention are functional in a ceU, tissue
or organ of a monocot or dicot plant and include cell-, tissue- and organ-specific promoters, ceU
cycle specific promoters, temporal promoters, inducible promoters, constitutive promoters that
are active in most plant tissues, and recombinant promoters. Choice o f promoter will depend
upon the temporal and spatial expression of the cloned polynucleotide, so desired. The
promoters may be those normaUy associated with a transgene of interest, or promoters which are
derived from genes of other plants, viruses, and plant pathogenic bacteria and fungi. Those
skiUed in the art will, without undue experimentation, be able to select promoters that are
suitable for use in modifying and modulating plant traits using genetic constructs comprising the
polynucleotide sequences of the invention. Examples of constitutive plant promoters include
the CaMV 35S promoter, the nopaline synthase promoter and the octopine synthase promoter,
and the Ubi 1 promoter from maize. Plant promoters which are active in specific tissues
respond to internal developmental signals or external abiotic or biotic stresses are described in
the scientific literature. Exemplary promoters are described, e.g., in WO 02/00894 and
WO2011/053169, which is herein incorporated by reference.
Exemplary terminators that are commonly used in plant transformation genetic construct
include, e.g., the cauliflower mosaic virus (CaMV) 35S terminator, the Agrobacterium tumefaciens
nopaline synthase or octopine synthase terminators, the Zea mays zein gene terminator, the Ory^a
sativa ADP-glucose pyrophosphorylase terminator and the Solanum tuberosum PI-II terminator.
Selectable markers commonly used in plant transformation include the neomycin
phophotransferase II gene (NPT II) which confers kanamycin resistance, the aadA gene, which
confers spectinomycin and streptomycin resistance, the phosphinothricin acetyl transferase (bar
gene) for Ignite (AgrEvo) and Basta (Hoechst) resistance, and the hygromycin
phosphotransferase gene ( hpt) for hygromycin resistance.
Use of genetic constructs comprising reporter genes (coding sequences which express an activity
that is foreign to the host, usually an enzymatic activity and/ or a visible signal (e.g., luciferase,
GUS, GFP) which may be used for promoter expression analysis in plants and plant tissues are
also contemplated. The reporter gene literature is reviewed in Herrera-Estrella et al, 1993,
Nature 303, 209, and Schrott, 1995, In: Gene Transfer to Plants (Potrykus, T., Spangenberg.
Eds) Springer Verlag. Berline, pp. 325-336.
The following are representative publications disclosing genetic transformation protocols that
can be used to genetically transform the following plant species: Rice (Alam et al, 1999, Plant
Cell Rep. 18, 572); apple (Yao et al, 1995, Plant Cell Reports 14, 407-412); maize (US Patent
Serial Nos. 5, 177, 010 and 5, 981, 840); wheat (Ortiz et al, 1996, Plant Cell Rep. 15, 1996, 877);
tomato (US Patent Serial No. 5, 159, 135); potato (Kumar et al, 1996 Plant J . 9, : 821); cassava
(Li et al, 1996 Nat. Biotechnology 14, 736); lettuce (Michelmore et al, 1987, Plant Cell Rep. 6,
439); tobacco (Horsch et al., 1985, Science 227, 1229); cotton (US Patent Serial Nos. 5, 846, 797
and 5, 004, 863); grasses (US Patent Nos. 5, 187, 073 and 6. 020, 539); peppermint ( iu et al,
1998, Plant Cell Rep. 17, 165); citrus plants (Pena et al., 1995, Plant Sci.104, 183); caraway (Krens
etal, 1997, Plant Cell Rep, 17, 39); banana (US Patent Serial No. 5, 792, 935); soybean (US
Patent Nos. 5, 416, Oil ; 5, 569, 834 ; 5, 824, 877 ; 5, 563, 04455 and 5, 968, 830); pineapple (US
Patent Serial No. 5, 952, 543); poplar (US Patent No. 4, 795, 855); monocots in general (US
Patent Nos. 5, 591, 616 and 6, 037, 522); brassica (US Patent Nos. 5, 188, 958 ; 5, 463, 174 and 5,
750, 871); cereals (US Patent No. 6, 074, 877); pear (Matsuda eta/., 2005, Plant Cell Rep.
24(1):45-51); Primus (Ramesh eta/., 2006 Plant Cell Rep. 25(8):821-8; Song and Sink 2005 Plant
Cell Rep. 2006 ;25(2):117-23; Gonzalez Padilla eta/., 2003 Plant Cell Rep.22(l):38-45); strawberry
(Oosumi eta/., 2006 Planta. 223(6):1219-30; Folta eta/., 2006 Planta Apr 14; PMID: 16614818),
rose (Li eta/., 2003), Rubus (Graham eta/., 1995 Methods Mol Biol. 1995;44:129-33), tomato
(Dan eta/., 2006, Plant Cell Reports V25:432-441), apple (Yao eta/., 1995, Plant Cell Rep. 14, 407-
412), Canola (Brassica napus L.).(Cardoza and Stewart, 2006 Methods Mol Biol. 343:257-66),
safflower (Orlikowska et al, 1995, Plant Cell Tissue and Organ Culture 40:85-91), ryegrass
(Altpeter et al, 2004 Developments in Plant Breeding ll(7):255-250), rice (Christou et al, 1991
Nature Biotech. 9:957-962), maize (Wang et al, 2009 In: Handbook of Maize pp. 609-639) and
Actinidia eriantha (Wang et al, 2006, Plant Cell Rep. 25,5: 425-31). Transformation of other
species is also contemplated by the invention. Suitable methods and protocols are available in
the scientific literature.
BRIEF DESCRIPTION OF THE FIGURES
Figure 1 shows the nucleic acid sequence and three frame translation of the Arabidopsis thaliana
DGATl transcribed region (SEQ ID NO:128). Exon coding sequences are shown in bold face,
underlined, grey blocks.
Figure 2 shows the nucleic acid sequence and three frame translation of the Zea mays short
DGATl transcribed region (SEQ ID NO:129). This genomic sequence has F469 deleted and
Q67 added compared to the cDNA (EU039830) and peptide (ABV91586) sequences actually
used in this patent. Exon coding sequences are shown in bold face, underlined, grey blocks.
Figure 3 shows the peptide sequence of the N-terminal cytoplasmic region of a number of plant
DGATl s including both long and short versions from the grasses as well as examples from
dicotyledonous species. Left hand box represents acyl-CoA binding site (Nykiforuk et al, 2002,
Biochimica et Biophysica Acta 1580:95-109). Right hand box represents first transmembrane
region (McFie et al, 2010, JBC, 285:37377-37387). Left hand arrow represents boundary
between exon 1 and exon 2. Right hand arrow represents boundary between exon 2 and exon 3.
The sequences are AtDGATl (SEQ ID NO:130), BjDGATl (SEQ ID NO:131), BnDGATlAF
(SEQ ID NO:132), BjDGATl (SEQ ID NO:133), TmajusDGATl (SEQ ID NO:134),
EpDGATl (SEQ ID NO:135), VgDGATl (SEQ ID NO:136), NtDGATl (SEQ ID NO:137),
PfDGATl (SEQ ID NO:138), ZmL (SEQ ID NO:139), SbDGATl (SEQ ID NO:140), OsL
(SEQ ID NO:141), OsS (SEQ ID NO:142), SbDGATl (SEQ ID NO:143), ZmS (SEQ ID
NO:144), PpDGATl (SEQ ID NO:145), SmDGATl (SEQ ID NO:146), EaDGATl (SEQ ID
NO:147), VvDGATl (SEQ ID NO:148), GmDGATl (SEQ ID NO:149), GmDGATl (SEQ
ID NO:150), LjDGATl (SEQ ID NO:151), MtDGATl (SEQ ID NO:152), JcDGATl (SEQ
ID NO:153), VfDGATl (SEQ ID NO:154), RcDGATl (SEQ ID NO:155), PtDGATl (SEQ
ID NO:156), Pt DGAT1 (SEQ ID NO:157).
Figure 4 shows the line-bond structures of the amino acid residues lysine (K) and arginine (R).
EXAMPLES
Example 1: Plant DGAT1 sequence selection and splice site prediction
The majority of nucleic acid sequences and peptide sequences for the plant type 1 DGATs can
be found by accession number in public domain libraries (Table 1). For creating initial
alignments we used ClustalW (Thompson et al., 1994, Nucleic Acids Res., 22, 4673-4680); these
were manually edited and used to create the models to search the DGAT sequences, using the
HMMER2 package (HMMER 2.3.2 (Oct 2003) Copyright 1992-2003 HHMI /Washington
University School of Medicine, available from the World Wide Web at http:/ /hmmer.org).
Initial matching of protein sequences against genomic DNA with splice prediction was
performed with the GeneWise package (Birney et al., 2004, Genome Res. 14: 988-995). Some of
the sequences retrieved appeared to have errors; in particular incorrectly predicted splice sites
which would result in internal deletions that would likely result in non-functional proteins.
While both dicotyledonous and monocotyledonous type 1 DGATs have 16 exons there are
some differences in the position of the splicing. Exon 8 in the dicotylendonous DGAT1 gene
corresponds to exons 8 and 9 in the monocotyledonous DGAT1 gene, while exon 14 in the
monocotyledonous gene corresponds to exons 13 and 14 in the dicotyledonous gene. We have
found that the most accurate method for determing the likely genuine coding sequence from
genomic data has been to use Vector NTI Advance (TM) 11.0 ( 2008 Invitrogen Corporation)
to translate the genome in the three forward reading frames and align these with demonstrated
functional DGATls from dicotyledonous or monocotyledous species as appropriate (for
example A . thaliana cDNA NM_127503, protein NP_179535 and Z. mays cDNA EU039830,
protein ABV91586). The genomic sequence and corresponding exon/intron boundary positions
for Arabidopsis thaliana encoding NP_179535 and Zea mays encoding ABV91586 that can be used
as a template for determining other plant DGAT coding regions are shown in Figures 1 and
Figures 2, respectivlely. An example of this template use is shown for the determination of Z.
mays DGAT1 SEQ ID NO: 10 and SEQ ID NO: 39.
Table 1
Example 2 : Production of Chimeric DGAT1 proteins for expression in cells
Nucleic acid constructs encoding the amino acid sequences, SEQ ID NO: 30, 34, 39, 41, 42 and
44 (Table 1) were optimised for expression in S cch rom ces cerevisiae by GeneArt AG (Germany).
These were engineered to have an internal Xhol site within exon 1 encoding the conserved N -
terminal acyl-Co binding region (identified by Weselake 2006) without altering the amino acid
sequence leucine-serine-serine (LSS).
Figure 3 shows alignment of a number of DGAT1 sequences from plants. The left box shows
the position of the Acyl-CoA binding site.
An E co site was engineered upstream of the 5' coding sequence while an Xbal site was placed
downstream of the 3' stop codon. The internal Xhol and flanking EcoKL and Xbal sites were
used to generate chimeras between each of the original DGAT1 clones; essentially this fused the
N -terminal reputed cytoplasmic region (based on Weselake et al 2006 and McFie et al, 2010)
from one DGAT1 with the C-terminal ER luminal region of a different DGAT1. In some
combinations this resulted in one amino acid change in the remaining cytoplasmic region
downstream of the engineered Xhol site. The putative acyl-Co binding region the A . thaliana
DGAT1, T.majus DGAT1, Z . a s- DGATland O. sativa-L DGAT1 have an identical amino
acid sequence down stream of the Xhol site (LSSDAIFKQSHA). While in the Z . a s-
DGATland O. sativa-S DGAT1 the lysine (K) residue is replaced by an arginine (R) residue
(LSSDAIFRQSHA). Since the position of this residue is located 3' to the Xho I site encoded by
LLS then chimeras deriving from one parent containing the lysine and one parent containing the
arginine residue will effectively result in a substitution of this residue. This was considered to be
a minimal disruption since both lysine and arginine are large, positively charged, hydrophilic,
basic amino acids containing a free amine or guanidinium group, respectively at the end of an
aliphatic side chain (Figure 4). The complete list of N -terminal region / C-terminal region
domain swapping constructs are found in Table 2 , with the corresponding SEQ ID NO: 59-94.
Table 2
A. thaliana 0 . sativa-S V5-6xHis 60
A. thaliana 0 . sativa-L V5-6xHis 6 1
A. thaliana Z. mays-S V5-6xHis 62
A. thaliana Z. mays-L V5-6xHis 63
A. thaliana T. majus V5-6xHis 64
0 . sativa-S 0 . sativa-S V5-6xHis 65
0 . sativa-S A. thaliana V5-6xHis 66
0 . sativa-S 0 . sativa-L V5-6xHis 67
0 . sativa-S Z. mays-S V5-6xHis 68
0 . sativa-S Z. mays-L V5-6xHis 69
0 . sativa-S T. majus V5-6xHis 70
0 . sativa-L 0 . sativa-L V5-6xHis 7 1
0 . sativa-L A. thaliana V5-6xHis 72
0 . sativa-L 0 . sativa-S V5-6xHis 73
0 . sativa-L Z. mays-S V5-6xHis 74
0 . sativa-L Z. mays-L V5-6xHis 75
0 . sativa-L T. majus V5-6xHis 76
Z. mays-S Z. mays-S V5-6xHis 77
Z. mays-S A. thaliana V5-6xHis 78
Z. mays-S 0 . sativa-S V5-6xHis 79
Z. mays-S 0 . sativa-L V5-6xHis 80
Z. mays-S Z. mays-L V5-6xHis 8 1
Z. mays-S T. majus V5-6xHis 82
Z . mays-L Z. mays-L V5-6xHis 83
Z. mays-L A. thaliana V5-6xHis 84
Z. mays-L 0 . sativa-S V5-6xHis 85
Z. mays-L 0 . sativa-L V5-6xHis 86
Z. mays-L Z. mays-S V5-6xHis 87
Z. mays-L T. majus V5-6xHis 88
T. majus T. majus V5-6xHis 89
T. majus A. thaliana V5-6xHis 90
T. majus 0 . sativa-S V5-6xHis 9 1
T. majus 0 . sativa-L V5-6xHis 92
T. majus Z. mays-S V5-6xHis 93
T. majus Z. mays-L V5-6xHis 94
Sequences were synthesised either by GENEART AG (Germany) or GeneScript (USA).
Sequences were optimised for expression in S a ch rom ces cerevisiae and flanked with appropriate
incorporated appropriate restriction sites to facilitate the cloning into the pYES2.1 vector
(Invitrogen).
Example 3 : Expression of chimeric DGAT1 sequences in cells
Expression of constructs in S . cerevisiae
The parent DGAT1 constructs and chimeric DGAT1 contstructs were placed into the galactoseinducible
yeast expression vector pYES2.1/V5-His TOPO ® (Invitrogen). This resulted in the
addition of an inframe C-terminal V5 epitope and 6x histidine tag. The name of the chimeric
constructs and the number of their corresponding peptide sequences are shown in Table 2.
The Saccharomyces cerevisiae quadruple mutant (H1246) in which all four neutral lipid biosynthesis
genes have been disrupted (Sandager et al., 2002, The Journal of Biological Chemistry, 277:6478-
6482) was transformed as per Elble (1992, BioTechniques 13, 18-20) and selected by the ability
to grow in the absence of uracil. Routinely, yeast cells were grown aerobically overnight in a
synthetic medium with 0.67% YNB, without uracil (SC-U) and containing 2% glucose. Cells
from overnight culture were used to inoculate 200 mL of induction medium (SC-U containing
2% galactose and 1% raffinose) to an initial D 00 of 0.4. Cells were allowed to further grow at
30°C, with shaking at 200 rpm until late stationary phase, normally 48 h. Cells were harvested by
centrifugation at 1500 x g for 5 min, then cell pellets were washed with distilled water and either
used immediately for subsequent analysis or kept in -80°C until required. Cell pellets for neutral
lipid extraction were freeze-dried for 48 h and stored in -20°C freezer until required.
Lipid anayl sis of S . cerevisiae
Approximately 0 mg of freeze-dried yeast cell material was accurately weighed then disrupted
using glass beads by vortexing for 1 minute. This lysate was extracted in hot methanolic HCL
for fatty acid methyl ester (FAME) analysis (Browse et al, 1986, Anal. Biochem. 152, 141-145).
For FA profile analysis approximately 50 mg freeze dried yeast was placed in a 3-mm screw cap
tube, and an equal volume of glass beads added before vortexing at high speed in 3x 1 min
bursts. Following addition of 50 mg of 19:0 TAG internal standard, 2.4 mL of 0.17 M NaCl in
MeOH was added and the mixture vortexed for 5 sec followed by the addition of then 4.8 mL
of heptane and the entire contents mixed.
The solution was then incubated in 80°C water bath for 2 h without shaking. After incubation,
the solution was cooled to room temperature. After cooling, the upper phase (lipidic phase) was
transferred to fresh screw-cap tube and evaporated to dryness under stream of nitrogen gas. The
dried residue was then dissolved in 1 mL heptane and mixed thoroughly for TAG SPE
separation using Strata Si-1 Silica column (Phenomenwx, 8B-S012-EAK).
After preconditioning with methanol and equilibrating the Silica column with heptanes the 1 mL
TAG extract (including 50 mg 17:0 TAG Internal Standard was passed through the preequilibrated
column, followed by 1.2 mL of heptane and then 2 mL of chloroform:heptane (1:9
v/v/) and the eluate collected.The total eluate collected was evaporated to dryness under the
stream of N gas and the residue used for FAMEs extraction.
FAMEs of extracted TAG
To the TAG residue above 10 m of internal standard 15:0 FA (4 mg/mL dissolved in heptane)
and 1 mL of methanolic HC1 (IN) reagent containing 5% of 2,2-dimeethoxypropane (as
water scavenger) were added.
The tube was then flushed with N gas, then sealed immediately with Teflon-lined cap, and
heated at 80°C in a water bath for 1 h. After cooling down, 0.6 mL heptane and 1.0 mL of 0.9%
(w/ v) NaCl was added, the mixture vortexed then spun at 500 rpm for 1 min.
From the top heptane layer, 100 m was collected and transfered to a flat-bottom glass insert
fitted into a vial for FAMES GC/MS analysis.
Protein extraction and Trypsin digestion
Yeast cell pellets were washed with lysis buffer (50 mM sodium phosphate, pH 7.4, 1 mM
EDTA, 5% glycerol, 1 mM PMSF) then resuspended in 500 m lysis buffer, glass beads were
added and cells disrupted by vortexing 2x at medium speed for 30 seconds. Cell debris was
pelleted by centrifugation at 1000 g for 5 min, the supernatant transferred to fresh tubes and
total cellular membranes pelleted by ultracentrifugation at 100,000 x g for 1 h. Membrane
proteins were resuspended in lysis buffer with or without detergent (1% Dodecyl maltoside) and
quantified in a Qubit Fluorometer using the Qubit IT Quantitation Kit.
Trypsin was added to give a final concentration of 25 mg/mL to 50 mΐ of protein extract and the
mixture incubated at 30°C for 30 min. The reaction was terminated by addition of Trypsin
inhibitor from Gyl cine max (Sigma-Aldrich catalogue # T6414) to a final concentration of 0.4
mg/ mL. After addition of trypsin inhibitor, 4x SDS loading dye and lOx reducing agent
(Invitrogen) were added, and the protein incubated at 70°C for 10 min prior to SDS-PAGE
followed by immunoblotting. The blot was probed with either Anti V5-HRP antibody (Cat
#R96125, Invitrogen) at 1:2500 dilution, or anti Kar2 (y-115) antibody produced in rabbit (SC-
33630, Santa Cruz Biotechnology) at 1:200 dilution. Anti Kar2 was used to detect the yeast
protein Kar2, an ER luminaly-located protein (Rose et al, 1989, Cell 57,1211-1221) which serves
as a control to demonstrate the presence of intact microsomes.
Example 4: Expression of chimeric DGATl in Brassica napus
The same strategy, as described in Example 2 , was used to generate a variety o f chimeric
DGATl constructs for expression in the seeds o f Brassica napus. This included the parent
DGATls o f 77. majus DGATl, Z. mays-L DGATl and Z. mays-S DGATl (amino acid SEQ
ID NO: 34, 39 and 44 respecitively, Table 1) optimised for expression in Brassica napus by
GeneArt AG. The 77. majus construct was engineered to contain a single point mutation
S197A (Xu et al., 2008, Plant Biotechnology Journal, 6:799-818). All constructs were
engineered to have an optimised Kozak, Arabidopsis thaliana UBQ10 intron, and
tetranucleotide stop codon as per Scott et al., (2010, Plant Biotechnology Journal, 8:912-917) as
indicated in Table 3 below.
Table 3
The same digestion pattern used to generate the chimeras for expression in S. cerevisiae
(Example 2) were used on the B . N -opt imised constructs to generate the chimeras TmZmS;
Tm-ZmL; ZmS-Tm(S170A); ZmL-Tm(S189A); resulting in the peptide sequences
listed in Table 4 (Region 1 DGAT1 chimeras for expression in Brassica napus).
Table 4
The parent DGATs and their chimeras were transferred into the Gateway -compatible binary
vector pMD107 (courtesy of Dr Mark Smith, NRC Saskatoon, SK, Canada, S7N 0W9) which
placed them under the control of the seed- specific napin promoter (Ellerstrom et al, 1996,
Plant Molecular Biology, Volume 32, Issue 6, pp 1019-1027).
Plant transformation
B. napus (cv. DH12075) was transformed via Agrobacterium tumefaciens (GV3101) using
the cotyledon co-cultivation method (adapted from that of Maloney et al., 1989, Plant Cell
Rep. 8, 238-242). Control lines contained an empty-vector, and when identified, null sibling
lines were subsequently used as true controls.
Approximately 200 T0 transformed lines were produced and their corresponding Ti selfed
seeds were analysed for oil content by GC. Approximately 50 individual transgenic lines
(including control lines) were selected for the next generation (10 plants/line) based on their
oil content, or seed weight (8 lines).
A total of approximately Ti plants were grown and screened by PCR for copy number and
identification of null sibing lines. T2 seeds were analysed in triplicate for oil content by
NMR.
Example 5: Expression of chimeric DGATl in Camelina sativa
The strategy above can also be used to generate a variety of chimeric DGATl constructs for
expression in the seeds of Camelina sativa and other plants.
Sequences with modifications were synthesised either by GENEART AG (Germany) or
GeneScript (USA). Sequences were optimised for expression in Brassica species and included an
intron (SEQ ID NO:105) from Arabidopsis thaliana DGATl —intron 3. Each sequence was
flanked with appropriate attL recombination sites sites to enable the cloning Gateway® adapted
vectors.
Table 5
DGATl DGATl
Residue C-terminal Additional Type of SEQ
N-terminal C-terminal modification mod information sequence ID NO:
parent parent
T.majus T. majus S197A V5-His tag + intron NUCLEIC 106
T.majus T. majus S197A V5-His tag ORF only NUCLEIC 107
T.majus T. majus S197A V5-His tag PEPTIDE 108
Z. mays-L Z. mays-L None V5-His tag + intron NUCLEIC 109
Z. mays-L Z. mays-L None V5-His tag ORF only NUCLEIC 110
Z. mays-L Z. mays-L None V5-His tag PEPTIDE 11
T.majus Z. mays-L None V5-His tag + intron NUCLEIC 112
T.majus Z. mays-L None V5-His tag ORF only NUCLEIC 113
T.majus Z. mays-L None V5-His tag PEPTIDE 114
Z. mays-L T. majus S189A V5-His tag + intron NUCLEIC 115
Z. mays-L T. majus S189A V5-His tag ORF only NUCLEIC 116
Z. mays-L T. majus S189A V5-His tag PEPTIDE 117
Z. mays-S Z. mays-S None V5-His tag + intron NUCLEIC 118
Z. mays-S Z. mays-S None V5-His tag ORF only NUCLEIC 119
Z. mays-S Z. mays-S None V5-His tag PEPTIDE 120
Z. mays-S T. majus S170A V5-His tag + intron NUCLEIC 121
Z. mays--S T. majus S170A V5-His tag ORF only NUCLEIC 122
Z. mays--S T. majus S170A V5-His tag PEPTIDE 123
T.majus z . mays-S None V5-His tag + intron NUCLEIC 124
T.majus z . mays-S None V5-His tag ORF only NUCLEIC 125
T.majus z . mays-S None V5-His tag PEPTIDE 126
The parent DGATs and their modified forms were transferred into the Gateway -compatible
binary pRShl Gateway adapted binary vector (Winichayakul et al., 2009, Biotechnol. Appl.
Biochem. 53, 111—122) modified by replacement of the CaMV35S promoter replaced with the
Brasska napus Napin promoter (SEQ ID NO:127).
Camelina sativa transformation
C. sativa (cf. Calena) were transformed via Agrobacterium tumefaciens (GV3101) using the floral
dip method (adapted from that of Clough and Bent, 1998, Plant J . 16(6):735-745). Essentially
seeds were sown in potting mix in 10 cm pots in a controlled environment, approximately 6
weeks after planting the flowers were dipped for 5-14 minutes under vacuum (70-80 inch Hg) in
an overnight culture of appropriated Agrobacterium GV3101 cells re-suspended in a floral dip
buffer. After vacuum-transformation, plants were kept for 24 h under low light conditions by
partly covering with a black plastic sheet. Vacuum transformations can be repeated three times at
approximately 10-12 days intervals, corresponding to the flowering duration. Plants were grown
in potting mix in a controlled environment (16-h day length, 21-24 °C, 65-70 % relative
humidity).
The Ύ seeds produced can be collected and screened for transformants by germinating and
growing seedlings at 22 °C with continuous light on a half-strength MS medium (pH 5.6)
selection plate containing 1 %(w/v) sucrose, 300 mg/L Timentin, and 25 mg/L DLphosphinothricin
to select for herbicide resistance. T2 selfed seed populations can also be
screened by immuno blot for the presence of the V5 eptiope.
T2 selfed seeds may be analysed for oil content by GC. Approximately 50 individual transgenic
lines (including control lines) may be selected for the next generation (10 plants/line) based on
their oil content, or seed weight. T2 plants may be grown and screened by PCR for copy number
and identification of null sibing lines. T2 seeds may be analysed in triplicate for oil content by
NMR or GC/MS.
Results
Swapping the N-terminal region of plant DGATls enhances lipidproduction in Saccharomjces cerevisiae
The N-terminal cytoplasmic region can be swapped between different plant DGATls to raise
the lipid yield. Tables 5-1 1 show the lipid yields of a variety of chimeric DGATls in which
the N-terminal cytoplasmic region has been derived from one plant DGAT1 while the
remainder of the protein has been derived from another plant DGAT1. The lipid yields are
presented either as grams of lipid produced per litre (which therefore compensates for any
differences in growth rate) or have been normalised as a percentage of the lipid yield of the
corresponding unmodified parent DGAT1.
A comparison of parent DGATls and chimeric DGATls made using one donor parent for the
N-terminal region, and a different donor parent for the N-terminal region are shown in Table
5. The lipid yields at 32 hr have been normalised against the highest lipid-producing parent
(Z. mays-V) and are presented in ascending order.
A comparison of T. majus parent DGATls and chimeric DGATls made using either T. majus
as the donor parent for the N-terminal region or using T. majus as the donor parent for the Cterminal
region are shown in Table 6. The lipid yields at 32 hr have been normalised against
the lipid yield from the parent DGAT1 of the C-terminal region.
A comparison of O. Sativa-L parent DGATls and chimeric DGATls made using either O.
Sativa-L as the donor parent for the N-terminal region or using O. Sativa-L as the donor
parent for the C-terminal region are shown in Table 7. The lipid yields at 32 hr have been
normalised against the lipid yield from the parent DGAT1 of the C-terminal region. NA =
not available.
A comparison of Z. mays-L parent DGATls and chimeric DGATls made using either Z.
mays-L as the donor parent for the N-terminal region or using Z. mays-L as the donor parent
for the C-terminal region are shown in Table 8. The lipid yields at 32 hr have been
normalised against the lipid yield from the parent DGAT1 of regions 2-4. NA = not
available.
A comparison of O. sativa-S parent DGATls and chimeric DGATls made using either O.
sativa-S as the donor parent for the N-terminal region or using O. sativa-S as the donor parent
for the C-terminal region are shown in Table 9. The lipid yields at 32 hr have been
normalised against the lipid yield from the parent DGAT1 of the C-terminal region. NA =
not available.
A comparison of Z. mays-S parent DGATls and chimeric DGATls made using either Z.
mays-S as the donor parent for the N-terminal region or using Z. mays-S as the donor parent
for the C-terminal region are shown in Table 10. Lipid yields at 32 hr have been normalised
against the lipid yield from the parent DGAT1 of the C-terminal region. NA = not available.
A comparison of A. thaliana parent DGATls and chimeric DGATls made using either A.
thaliana as the donor parent for the N-terminal region or using A. thaliana as the donor parent
for the C-terminal region are shown in Table 11. The lipid yields at 32 hr have been
normalised against the lipid yield from the parent DGAT1 of the C-terminal region. NA =
not available.
Table 5
T. majus A. thaliana 90 88.69
Z. mays-S 0 . sativa-L 80 88.91
0 . sativa-S Z. mays-S 68 89.1 1
0 . sativa-L A. thaliana 72 93.02
Z. mays-S 0 . sativa-S 79 94.15
0 . sativa-L Z. mays-S 74 94.51
0 . sativa-S Z. mays-L 69 95.81
Z. mays-L 0 . sativa-L 86 96.17
Z. mays-L A. thaliana 84 97.53
0 . sativa-S T. majus 70 98.52
Z. mays-L Z. mays-L 83 100.00
T. majus Z. mays-L 94 100.71
0 . sativa-L T. majus 76 102.78
0 . sativa-L Z. mays-L 75 104.29
Z. mays-L 0 . sativa-S 85 105.02
0 . sativa-S A. thaliana 66 105.96
Table 6
Table 7
A. thaliana 0 . sativa-L 6 1 43.43
T. majus 0 . sativa-L 92 75.43
Z. mays-S 0 . sativa-L 79 100.79
0 . sativa-S 0 . sativa-L 67 N/A
Z. mays-L 0 . sativa-L 86 112.03
Table 8
N-terminal region Lipid yield
C-terminal region SEQ as % of the parent
DGAT1
DGAT1parent ID NO: of C-terminal
Parent
region
Z. mays -L Z. mays -L 83 100
Z. mays -L T. majus 88 108.65
Z. mays -L A. thaliana 84 189.61
Z. mays -L 0 . sativa -L 86 112.03
Z. -L Z. mays-S 87 N/A
Z. mays -L 0 . sativa-S 85 135.81
thaliana Z. mays -L 63 38.28
T. majus Z. mays -L 94 100.61
Z. mays-S Z. mays -L 8 1 N/A
0 . sativa-S Z. mays -L 69 101.42
0 . sativa -L Z. mays -L 75 104.29
Table 9
Lipid yield
N-terminal region C-terminal region SEQ
as % of the parent
DGAT1 parent DGAT1 parent ID NO: of C-terminal region
0 . sativa-S 0 . sativa-S 65 100
0 . sativa-S T. majus 70 142.91
0 . sativa-S A. thaliana 66 178.00
0 . sativa-S 0 . sativa -L 67 N/A
0 . sativa-S Z. mays-S 68 128.84
0 . sativa-S Z. mays -L 69 101.42 or 90.21
A. thaliana 0 . sativa-S 60 65.19
T. majus 0 . sativa-S 9 1 95.41
Z. mays-S 0 . sativa-S 79 125.26
Z. mays -L 0 . sativa-S 85 135.81
0 . sativa -L 0 . sativa-S 73 N/A
Table 10
N-terminal region C-terminal region SEQ Lipid yield
DGAT1 DGAT1parent ID NO: as % of the parent
Parent of C-terminal region
Z . mays-S Z . mays-S 77 100
Z . mays-S Z . mays-L 8 1 N/A
Z . mays-S 0 . sativa-L 80 100.79
Z . mays-S 0 . sativa-S 79 125.26
Z . mays-S T. majus 82 112.92
Z . mays-S A . thaliana 78 170.39
T. majus Z . mays-S 93 105.30
0 . sativa-L Z . mays-S 74 129.16
A . thaliana Z . mays-S 62 67.52
0 . sativa-S Z . mays-S 68 128.84
Z . mays-L Z . mays-S 87 N/A
Table 11
Swapping the N-terminal region of plant DGATls alters substrate specificity
The ability to change substrate specifity of the plant DGATls through swapping the JV-terminal
regions is shown in Table which demonstrates that the lipid profile of the TAG extracted
from Saccharomjces cerevisiae cells over-expressing plant DGATl's is determined predominantly by
which the donor of the N-terminal region. In the examples given this is specifically seen as a
relatively high level of 16:0 and 18:0 but low level of 18:1 c9 in the TAG extracted from cells
expressing DGATls in which the JV-terminal region was derived from Arabidopsis thaliana. In
contrast the TAG from cells expressing DGATls in which the JV-terminal region was derived
from O. sativa-L have relatively low levels of 16:0 and 18:0 but high levels of 18:1 c9. While the
TAG from cells expressing DGATl s in which the N -terminal regions was derived from T. majus
have intermediate levels of 16:0, 18:0 and 18:lc9.
Table 12
Swapping the N-terminal region of plant DGATIs enhances lipidproduction in brassica napus
The N-terminal region can be swapped between different plant DGATIs to raise the oil
content in Brassica napus seeds. Tables 13-14 show the seed oil contents from a variety of
transgenic plants containing chimeric DGATIs in which the N-terminal region has been
derived from one plant DGATl while the remainder of the protein (the C-terminal region)
has been derived from another plant DGATl . In Table 13 the seed oil contents are presented
both as a % of Dry Matter (DM) and as a normalised percentage of the seed oil content of the
corresponding unmodified DGATl parents.
Table 13
Z. mays-L N6 38.96 2.55 N/A N/A
Tm-ZmS 182-38-4 44.66 17.56 14.31 10.96
Tm-ZmS 182-38-9 43.05 13.32 10.19 6.96
Tm-ZmS 182-52-5 46.20 21.61 18.25 14.78
Tm-ZmS 182-52-9 43.37 14.16 11.01 7.75
Tm-ZmS 182-52-10 43.30 13.98 10.83 7.58
Tm-ZmL 183-17-10 43.80 15.29 12.1 1 12.42
Tm-ZmL 183-60-6 44.47 17.06 13.82 14.14
ZmS-Tm 184-17-1 43.38 14.19 7.78 11.03
ZmS-Tm 184-26-10 43.94 15.66 9.17 12.46
ZmL-Tm 185-24-5 45.27 19.16 16.20 15.87
ZmL-Tm 185-24-9 45.14 18.82 15.86 15.54
ZmL-Tm 185-22-1 44.23 16.43 13.53 13.21
ZmL-Tm 185-22-4 43.20 13.71 10.88 10.57
ZmL-Tm 185-22-9 43.49 14.48 11.63 11.31
ZmL-Tm 185-14-10 44.77 17.85 14.91 14.59
ZmL-Tm 185-9-9 43.73 15.1 1 12.24 11.93
ZmL-Tm 185-8-4 44.02 15.87 12.99 12.67
ZmL-Tm 185-8-7 45.1 1 18.74 15.79 15.46
ZmL-Tm 185-8-8 44.62 17.45 14.53 14.21
ZmL-Tm 185-8-9 43.48 14.45 11.60 11.29
In Table 14 the oil contents are presented both on a % of DM basis and as a normalised
percentage of the seed oil content of the corresponding segregating null sibling.
Table 14
ZmS-Tm 184-26-10 43.94 15.66
ZmS-Tm
184-26-2 37.99 N/A
Null Sib
ZmS-Tm 184-26-10 43.94 31.99
ZmS-Tm
184-26-6 33.29 N/A
Null Sib
ZmL-Tm 185-24-5 45.27 19.41
ZmL-Tm 185-24-9 45.14 19.07
ZmL-Tm
185-24-10 37.91 N/A
Null Sib
ZmL-Tm 185-22-1 44.23 30.09
ZmL-Tm 185-22-4 43.2 27.06
ZmL-Tm 185-22-9 43.49 27.91
ZmL-Tm
185-22-2 34 N/A
Null Sib
ZmL-Tm 185-9-9 43.73 15.60
ZmL-Tm
185-9-8 37.83 N/A
Null Sib
Discussion
The applicants have thus shown that the chimeric DGATl proteins of the invention can be used
to manipulate cellular lipid accumulation and cellular lipid profile. More specifically they can be
used to achieve higher levels of lipid accumulation in eukaryotic cells than can be achieved using
unaltered DGATl proteins. They have also shown that by selceting to express specific chimeric
DGATl proteins they can not only increase the lipid content of the eukaryotic cell but also alter
the lipid profile within the accumulating TAG.
There is discussion of producing chimeric plant DGATls in US 2012/0156360 Al. In Example
11, the authors describe two chimeras using the N-terminus from a maize DGATl and the Cterminus
from a hazelnut DGATl. However, the junction of the chimeras is in the putative
transmembrane domain which is further downstream from the junction of the chimeras
described by the present applicants. Furthermore, there is no data presented with respect to the
activity of the chimeric plant DGATls in US 2012/ 0156360 Al. Thus there is no disclosure in
US 2012/0156360 Al of the chimeric DGATl molecules presented herein, or the altered
activities specified, or use of the chimeras of the invention to produce the effects described
herein.

CLAIMS
1. An isolated polynucleotide encoding a chimeric DGATl protein that comprises:
a) at its N-terminal end, an N-terminal portion of a first DGATl protein, and
b) at its C-terminal end, a C-terminal portion of a second DGATl protein.
2. The polynucleotide of claim 1 wherein the chimeric DGATl protein has at least one of:
i) increased DGATl activity
it) increased stability
iit) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to the first DGATl, the second DGATl, or both the first DGATl and the second
DGATl.
3. The polynucleotide of claim 1 or 2 wherein the N-terminal portion of a first DGATl
protein is the N-terminal cytoplasmic region of the first DGATl protein.
4. The polynucleotide of any one of claims 1 to 3 wherein the N-terminal cytoplasmic
region of the first DGATl protein extends from the N-terminus of the first DGATl
protein to the end of the acyl-CoA binding domain of the first DGATl protein.
5. The polynucleotide of any one of claims 1 to 3 wherein the N-terminal cytoplasmic
region of the first DGATl protein is the region upstream of the first transmembrane
domain.
6. The polynucleotide of any one of claims 1 to 3 wherein the junction between the N -
terminal portion of a first DGATl protein and the C-terminal portion of a second
DGATl protein is upstream of the first transmembrane domain.
7. The polynucleotide of any one of claims 1 to 3 wherein the junction between the N -
terminal portion of a first DGATl protein and the C-terminal portion of a second
DGATl protein is in the acyl-CoA binding site of first and second DGATl protein.
8 . The polynucleotide o f any one o f claims 1 t o 3 wherein the N-terminal portion o f a first
DGATl protein and the C-terminal portion o f a second DGATl protein i s a t a
corresponding poition in the acyl-CoA binding site o f the first and second DGATl
protein.
9 . The polynucleotide o f any one o f claims 1 t o 3 wherein the junction between the N -
terminal portion o f a first DGATl protein and the C-terminal portion o f a second
DGATl protein i s within the conserved LSS (Leu-Ser-Ser) in the acyl-CoA binding site
o f the first and second DGATl protein.
10. The polynucleotide o f any one o f claims 1 to 9 wherein the chimeric DGATl has an
intact acyl-CoA binding site.
The polynucleotide ooff aannyy oonnee ooff ccllaaiimmss 1 to 9 wherein the acyl-CoA binding site in the
chimeric DGATl i s ooff tthhee ssaammee lleennggtthh aass ithe acyl-CoA binding site in the first DGATl
protein.
12. The polynucleotide ooff aannyy oonnee ooff ccllaaiimmss 1 ttoo 9 wherein the acyl-CoA binding site in the
chimeric DGATl i s ooff tthhee ssaammee lleennggtthh aass tthhee acyl-CoA binding site in the second
DGATl protein.
13. The polynucleotide o f any one o f claims 1 to 9 wherein the acyl-CoA binding site in the
chimeric DGATl i s o f the same length a s the acyl-CoA binding site in the first and
second DGATl protein.
14. The polynucleotide o f any one o f claims 1 to 9 wherein the chimeric DGATl protein,
when expressed in the cell, has altered substrate specificity relative t o a t least one o f the
first and second DGATl proteins.
15. A genetic construct comprising a polynucleotide o f any one o f claims 1 t o 15.
16. A cell comprising a polynucleotide o f any one o f claims 1 t o 15.
17. The cell o f claim 16 that expresses the chimeric DGATl.
8. The cell of claim 14 wherein the chimeric DGATl protein has at least one of:
i) increased DGATl activity,
it) increased stability,
iit) altered oligomerisation properties,
iv) substantially normal cellular protein accumulation properties, and
v) substantially normal subcellular targeting properties
relative to the first DGATl, the second DGATl, or both the first DGATl and the second
DGATl.
9. The cell of any one of claims 6 to 18 which produces more lipid than does a control
cell.
20. The cell of any one of claims 6 to 8 which has an altered lipid profile relative to a
control cell.
21. The cell of any one of claims 6 to 20 which is also transformed to express at least one
of: an oleosin, steroleosin, caloleosin, polyoleosin, and an oleosin including at least one
artificially introduced cysteine.
22. A plant comprising the polynucleotide of of any one of claims 1 to 14.
23. The plant of claim 22 that expresses the chimeric DGATl.
24. The plant of claim 23 wherein the chimeric DGATl protein when expressed in the plant
has at least one of:
i) increased DGATl activity,
it) increased stability,
ii ) altered oligomerisation properties,
iv) substantially normal cellular protein accumulation properties, and
v) substantially normal subcellular targeting properties
relative to the first DGATl, the second DGATl, or both the first DGATl and the second
DGATl.
25. The plant of any one of claims 22 to 24 that produces more lipid, in at least one of its
tissues or parts, or as a whole, than does a control plant.
26. The plant of any one of claims 22 to 25 that has an altered lipid profile, in at least one of
its tissues or parts, or as a whole, relative to a control plant.
27. The plant of any one of claims 22 to 26 that is also transformed to express at least one
of: an oleosin, steroleosin, caloleosin, polyoleosin, and an oleosin including at least one
artificially introduced cysteine.
28. A chimeric DGATl protein that comprises:
a) at its N-terminal end, an N-terminal portion of a first DGATl protein, and
b) at its C-terminal end, a C-terminal portion of a second DGATl protein.
29. The chimeric DGATl protein of claim 28 that has at least one of:
i) increased DGATl activity
it) increased stability
iit) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to the first DGATl, the second DGATl, or both the first DGATl and the second
DGATl.
30. The chimeric DGATl protein of claim 29, wherein the chimeric DGATl is as described
in any one of claims 1 to 14.
31. A method for producing a chimeric DGATl protein the method comprising combining:
a) an N-terminal portion of a first DGATl protein, and
b) a C-terminal portion of a second DGATl protein.
32. The method of claim 3 1 whereinthe chimeric DGATl protein produced comprises:
a) at its N-terminal end, the N-terminal portion of a first DGATl protein, and
b) at its C-terminal end, the C-terminal portion of a second DGATl protein.
33. The method of claim 3 1 or 32 wherein the chimeric DGATl is as described in any one
of claims 1 to 14.
34. The method of any one of claims 3 1 or 33 wherein the chimeric DGATl protein has at
least one of:
i) increased DGATl activity
it) increased stability
iit) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to the first DGATl, the second DGATl, or both the first DGATl and the second
DGATl.
35. The method of any one of claims 3 1 or 34 wherein the method comprises the step of
testing at least one of the
i) activity
it) stability
iit) oligomerisation properties
iv) cellular protein accumulation properties
v) cellular targeting properties
of the chimeric DGATl protein.
36. The method of any one of claims 3 1 or 35 wherein method comprises the step selecting
a chimeric DGATl protein that has at least one of:
i) increased DGATl activity
it) increased stability
iit) altered oligomerisation properties
iv) substantially normal cellular protein accumulation properties
v) substantially normal cellular targeting properties
relative to the first DGATl, the second DGATl, or both the first DGATl and the second
DGATl.
37. A part, propagule or progeny of the plant of any one of claims 22 to 23.
38. The part, propagule or progeny of claim 37 that comprises at least one of the
polynucleotide of any one of claims 1 to 14 or the chimeric DGAT1 protein of any one
of claims 28 to 30.
39. The part, propagule or progeny of claim 37 or 38 that produces more lipid than does a
control part, propagule or progeny, or part, propagule or progeny of a control plant.
40. The part, propagule or progeny of any one of claims 37 to 39 that has an altered lipid
profile relative to a control part, propagule or progeny, or part, propagule or progeny of
a control plant.
4 . An animal feedstock comprising at least one of a polynucleotide, construct, chimeric
DGAT1 protein, cell, plant cell, plant part, propagule and progeny of any one of claims
1-30 and 37 to 40.
42. An bio fuel feedstock comprising at least one of a polynucleotide, construct, chimeric
DGAT1 protein, cell, plant cell, plant part, propagule and progeny of any one of claims
1-30 and 37 to 40.
43. A method for producing lipid, the method comprising expressing a modified DGAT
protein of any one of claims 28 to 30 in a plant.
44. The method of claim 43 wherein expressing the modified DGAT1 protein of the
invention in a plant leads to production of the lipid in the plant.
45. The method of claim 43 or 44 wherein the method includes the step of transforming a
plant cell or plant with a polynucleotide of any one of claims 1 to 14 encoding the
modified DGAT1 protein.
46. The method of any one of claims 43 to 45 which includes the step of extracting the lipid
from the cell, plant cell, or plant, or from a part, propagule or progeny of the plant.
47. A method for producing lipid, the method comprising extracting lipid from at least one
of a cell, plant cell, plant, plant part, propagule and progeny of any one of claims 6 to 27
and 37 to 40.
48. The method of any one of claims 43 to 47 wherein the lipid is processed into at least one
of:
a) a fuel,
b) an oleochemical,
c) a nutritional oil,
d) a cosmetic oil,
e) a polyunsaturated fatty acid (PUFA), and
f) a combination of any of a) to e).