U.S. patent application number 10/928689 was filed with the patent office on 2005-01-20 for plants with enhanced ability to produce starch and methods for obtaining them.
Invention is credited to Chung, Hwa Jee, Ferl, Robert J., Hannah, L. Curtis, Sehnke, Paul C., Wu, Ke.
Application Number | 20050014269 10/928689 |
Document ID | / |
Family ID | 22759260 |
Filed Date | 2005-01-20 |
United States Patent
Application |
20050014269 |
Kind Code |
A1 |
Ferl, Robert J. ; et
al. |
January 20, 2005 |
Plants with enhanced ability to produce starch and methods for
obtaining them
Abstract
The subject invention concerns materials and methods for
enhancing starch production in plants. Starch production is
enhanced, relative to levels observed in wildtype or control
plants, by reduction of the plant 14-3-3 protein(s) which
subsequently results in increased accumulation of starch in the
plant. In one embodiment, the 14-3-3 protein expression is reduced
using polynucleotides that are antisense to the 14-3-3 gene
sequences expressed in the plant. In another embodiment, the 14-3-3
protein expression is reduced by "knockout" of a 14-3-3 gene or
gene sequences. The subject invention also pertains to transformed
and transgenic plants that have polynucleotides that are antisense
to the 14-3-3 gene sequences expressed in the plant, wherein the
transformed and transgenic plants exhibit enhanced starch
production. The subject invention also pertains to "knockout"
plants in which the normal functional 14-3-3 gene in the plant is
deleted or replaced with a non-functional form of the gene. The
subject invention also concerns the "antisense" polynucleotides of
the invention that when introduced into a plant cell can function
to effectively reduce expression of the 14-3-3 proteins in a
plant.
Inventors: |
Ferl, Robert J.;
(Gainesville, FL) ; Sehnke, Paul C.; (Gainesville,
FL) ; Chung, Hwa Jee; (Seoul, KR) ; Wu,
Ke; (Gainesville, FL) ; Hannah, L. Curtis;
(Gainesville, FL) |
Correspondence
Address: |
SALIWANCHIK LLOYD & SALIWANCHIK
A PROFESSIONAL ASSOCIATION
PO BOX 142950
GAINESVILLE
FL
32614-2950
US
|
Family ID: |
22759260 |
Appl. No.: |
10/928689 |
Filed: |
August 26, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10928689 |
Aug 26, 2004 |
|
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|
09859822 |
May 17, 2001 |
|
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60204746 |
May 17, 2000 |
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Current U.S.
Class: |
435/468 ;
800/285; 800/286; 800/294 |
Current CPC
Class: |
C12N 15/8245
20130101 |
Class at
Publication: |
435/468 ;
800/285; 800/294; 800/286 |
International
Class: |
A01H 001/00; C12N
015/82; C12N 015/87 |
Goverment Interests
[0002] The subject invention was made with government support under
a research project supported by USDA NRI Grant Nos. 00-35304-9601
and 97-35304-4942. The government has certain rights in this
invention.
Claims
We claim:
1. A method for enhancing starch production in a plant, said method
comprising inhibiting the expression of a 14-3-3 protein of said
plant or inhibiting function of a 14-3-3 protein of said plant.
2. The method according to claim 1, wherein a polynucleotide
encoding a plant 14-3-3 protein, or a fragment thereof, is
introduced into a plant cell of said plant.
3. The method according to claim 2, wherein said polynucleotide is
provided in a recombinant vector.
4. The method according to claim 2, wherein said polynucleotide is
introduced by Agrobacterium infection, biolistic transfection,
electroporation, microinjection, or virus-mediated transformation
of said cell.
5. The method according to claim 2, wherein said polynucleotide
encodes a 14-3-3 Mu protein, or a fragment thereof.
6. The method according to claim 5, wherein said 14-3-3 Mu protein
has the amino acid sequence shown in SEQ ID NO. 4.
7. The method according to claim 6, wherein said polynucleotide
comprises the coding sequence of the nucleotide sequence shown in
SEQ ID NO. 3.
8. The method according to claim 2, wherein said polynucleotide
encodes a 14-3-3 Epsilon protein, or a fragment thereof
9. The method according to claim 5, wherein said 14-3-3 Epsilon
protein has the amino acid sequence shown in SEQ ID NO. 2.
10. The method according to claim 9, wherein said polynucleotide
comprises the coding sequence of the nucleotide sequence shown in
SEQ ID NO. 1.
11. The method according to claim 2, wherein a plant is grown from
said cell in which said polynucleotide has been introduced.
12. The method according to claim 1, wherein expression of said
14-3-3 protein is inhibited by: a) expressing a polynucleotide in
said plant that has a nucleotide sequence that is antisense to the
nucleotide sequence that encodes said 14-3-3 protein; or b)
deleting the nucleotide sequence that encodes said 14-3-3 protein
or replacing the nucleotide sequence that encodes said 14-3-3
protein with a nucleotide sequence that encodes a non-functional
form of said 14-3-3 protein or that renders said 14-3-3 protein
non-functional
13. The method according to claim 1, wherein function of said
14-3-3 protein is inhibited by expressing a polynucleotide that
encodes an antibody, a functional fragment of said antibody, or an
aptamer in said plant, wherein said antibody and said aptamer can
bind to and inhibit the function of said 14-3-3 proteins in said
plant.
14. The method according to claim 1, wherein said plant is a
monocot.
15. The method according to claim 1, wherein said plant is a
dicot.
16. A method for preparing a plant that exhibits enhanced starch
production, said method comprising: a) deleting all or aportion of
a nucleotide sequence of said plant that encodes a 14-3-3 protein
or replacing the nucleotide sequence of said plant that encodes
said 14-3-3 protein with a nucleotide sequence that encodes a
non-functional form of said 14-3-3 protein or that renders said
14-3-3 protein non-functional; or b) inhibiting expression of a
14-3-3 protein of said plant by introducing a polynucleotide
encoding a plant 14-3-3 protein, or a fragment thereof, into said
plant or inhibiting function of a 14-3-3 protein of said plant by
introducing into and expressing in said plant a polynucleotide that
encodes an antibody, a functional fragment of said antibody, or an
aptamer to said 14-3-3 protein, wherein said antibody and said
aptamer can bind to and inhibit the function of said 14-3-3
proteins in said plant; or c) introducing into said plant a
polynucleotide that comprises a nucleotide sequence that is
antisense to the nucleotide sequence that encodes a 14-3-3
protein.
17. A plant or plant material exhibiting enhanced starch
production, wherein expression or function of a 14-3-3 protein of
said plant or plant material is inhibited.
18. The plant or plant material according to claim 17, wherein said
plant is a monocot or said plant material is from a monocot
plant.
19. The plant or plant material according to claim 18, wherein said
monocot is selected from the group consisting of maize, wheat,
barley, rice, and oats.
20. The plant or plant material according to claim 17, wherein said
plant is a dicot or said plant material is from a dicot plant.
21. The plant or plant material according to claim 20, wherein said
dicot is selected from the group consisting of tobacco, potato,
cabbage, soybeans, and sweet potato.
22. The plant or plant material according to claim 17, wherein said
plant or plant material is produced according to the method of
claim 16.
23. The plant or plant material according to claim 17, wherein said
plant material is selected from the group consisting of plant
tissue, plant cells, plant seeds, and protoplasts.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. application Ser.
No. 09/859,822, filed May 17, 2.001, which claims the benefit of
U.S. Provisional application Ser. No. 60/204,746, filed May 17,
2000.
BACKGROUND OF THE INVENTION
[0003] Carbon and nitrogen apportioning in plants has a direct
impact on their usefulness as agricultural commodities. Research
directed toward altered regulation and reallocation of these
assimilates represents amajor effort in agricultural biology at
both the biochemical and genetic levels. Several key enzymes in the
metabolic pathways that direct carbon and nitrogen flow, process
assimilates, and transfer the products into various sink tissues
are of intense investigative interest. The biosynthesis of starch
is one such well-regulated diurnal process (Smith, 1999; Preiss et
al., 1998), with starch serving as a major carbon reserve as well
as an energy source for plants and providing a major nutritional
value of food crops. The dynamic throughput of plant carbon demands
a tight, yet responsive, control of the key enzymes. To further add
to the complexity, starch production occurs exclusively in
membrane-bound plastids, thereby requiring import of the
biosynthetic enzymes and regulators involved. However, localization
within the plastid also serves to essentially distinguish enzymes
directly involved in starch synthesis and therefore identify
potential targets for genetic manipulation.
[0004] Starch is synthesized in leaves during the day from
photosynthetically assimilated carbon derived via the reductive
pentose phosphate pathway. One simple view of starch polymer
production involves four types of enzymes: ADP-glucose
pyrophosphorylase (AGP), starch synthases (SSs), starch-branching
enzymes (SBEs), and starch-debranching enzymes (DBEs) (Smith,
1999). AGP forms ADP-glucose from glucose 1-phosphate. SSs add
ADP-glucose to the elongating end of an a (1 -4)-linked
glucanchain, whereas SBEs cut .alpha.(1-4) links and rejoin them as
.alpha.(1-6) branches that are subsequently trimmed by DBEs to
yield short chains for further synthetic extension. However,
different isoforms of SSs (soluble and granule-associated SSI,
SSII, and SSIII) can participate in the production of branched
glucans. For example, the granule-bound SSI, the waxy-encoded
protein in maize, is directly and perhaps exclusively involved in
producing amylose, an .alpha.(1-4) glucan polymer with little
branching. In contrast, SSII participates in the synthesis of
amylopectin, an .alpha.(1-6) branched glucan polymer that typically
is found together with amylose to form starch granules. The ratio
of these two glucans affects the physical characteristics of starch
such as gelatinization and the absorption spectra of
iodine-complexed starch. The alteration or absence of certain
starch biosynthetic enzymes (Craig et al. 1998; Edwards et al.
1999; Lloyd et al. 1999) has a dramatic effect on the physical
characteristics of starch, as well as the level of starch
accumulated by the plant. In a similar, yet opposing, manner
dark-regulated starch degradation occurs by means of catabolic
enzymes such as amylase, .alpha.-glucosidase, and starch
phosphorylase. The resulting starch stasis is the consequence of
the metabolism and catabolism orchestrated by the respective
enzymes.
[0005] Regulation of some enzymes involved in major resource
allocation is affected by allosteric effectors, substrate levels,
and product levels, as well as by phosphorylation (Sokolov et al.,
1998; Sun et al., 1999; Imparl-Radosevich et al., 1999). For
several key enzymes, regulation of activity is a two-step process
involving phosphorylation of the enzyme, followed by formation of a
complex with 14-3-3 proteins to complete the regulatory transition
(Chung et al., 1999; Sehnke et al., 1997). For example, the
assimilation of nitrogen for production of amino acids or
nucleotide bases is tightly controlled by nitrate reductase (NR).
NR responds to environmental signals, such as light and metabolite
levels, byphosphorylation and interacts with 14-3-3 proteins
(Bachmann et al., 1996; Moorhead et al., 1996), thereby rapidly
altering nitrogen flux according to the plant's metabolic
requirements. This phosphorylation-dependent interaction of NR with
14-3-3 proteins has become a paradigm for posttranslational
regulation of metabolic enzymes (Chung et al., 1999). Recently,
14-3-3 proteins have been identified inside plastids (Sehnke et
al., 2000), thereby implicating a potential role in starch
regulation.
[0006] Several methods have previously been suggested for modifying
the ability of plants to produce and store starch. See, e.g., U.S.
Pat. Nos. 5,365,016; 5,498,831; 5,789,657; 5,792,920; 5,824,798;
5,830,724; 5,856,467; 5,959,180; 5,962,769; 5,981,852; 5,998,701;
and 6,013,861.
BRIEF SUMMARY OF THE INVENTION
[0007] The subject invention concerns materials and methods for
enhancing starch production in plants. Starch production is
enhanced, relative to levels observed in wildtype or control
plants, by reduction of the activity of plant 14-3-3 protein(s)
which subsequently results in increased accumulation of starch in
the plant. In one embodiment, the 14-3-3 protein expression is
reduced using polynucleotides that are antisense to the 14-3-3 gene
sequences expressed in the plant. In another embodiment, the 14-3-3
protein expression is reduced by "knockout" of a 14-3-3 gene or
gene sequences.
[0008] Methods of the present invention for enhancing starch
production in a plant include introducing into the plant a
polynucleotide of the invention that comprises a nucleotide
sequence that is antisense to the 14-3-3 DNA or RNA sequences in
the plant. Another method ofthe invention concerns deleting or
replacing the functional 14-3-3 genes in a plant with a
non-functional form of the gene.
[0009] The subject invention also pertains to transformed and
transgenic plants that have polynucleotides that are antisense to
the 14-3-3 gene sequences expressed in the plant, wherein the
transformed and transgenic plants exhibit enhanced starch
production.
[0010] The subject invention also pertains to "knockout" plants
which exhibit enhanced starch production, wherein the normal
functional 14-3-3 gene in the plant is deleted or replaced with a
non-functional form of the gene.
[0011] The subject invention also concerns the "antisense"
polynucleotides of the invention that when introduced into a plant
cell can function to effectively reduce expression of the 14-3-3
proteins in a plant.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIGS. 1A-1F show starch accumulation in transgenic GF14
antisense plants. Starch levels in wild-type (FIG. 1A) and GF14 E
(FIG. 1B) and [L (FIG. 1C) antisense plants grown under constant
light were assayed by iodine staining. The density of staining
clearly indicates increased starch levels in the leaves of
antisense plants. Identical photographic lighting and exposure
conditions were used for FIGS. 1A-1C so that the intensities of the
staining are directly comparable. Similar plants were subjected to
an 18-h dark period to allow for starch degradation before staining
(FIGS. 1D, 1E, and 1F, respectively), and the results indicate that
starch degradation is uninhibited in the 14-3-3 antisense
plants.
[0013] FIG. 2 shows altered starch composition of antisense starch
granules. The absorption spectra of iodine/starch complexes of
wild-type (FIG. 2, spectrum A) and 14-3-3 antisense (FIG. 2,
spectrum B) Arabidopsis starch granules indicate that the 14-3-3
.epsilon. antisense plants contain an increase in the relative
content of branched glucans.
[0014] FIGS. 3A-3C show immunolocalization of 14-3-3 proteins in
starch granules. Arabidopsis leaves were processed for electron
microscopy (Bihn et al., 1997) and immunolabeled with GF14
antibodies. Control antibodies to Dictyostelium spores (FIG. 3A)
did not immunodecorate the granules; however, antibodies that
recognize both .epsilon. (FIG. 3C) and non-.epsilon. (FIG. 3B)
14-3-3 proteins were concentrated inside the starch granules.
[0015] FIG. 4 shows reduction of GF14 .epsilon. and .mu. protein
levels in the starch granules of antisense plants and presence of
14-3-3 proteins in commercial corn starch. Isolated starch granules
from wild-type and antisense Arabidopsis were treated with
thermolysin to remove externally attached proteins and subjected to
SDS/PAGE Western analysis with 14-3-3 protein antibodies
(Mu-Forster et al., 1998). Protein extracts from 3 mg of starch
from wild- type (lanes 1 and 2), GF14 .epsilon. antisense (lane 3),
and GF14.mu. antisense (lane 4) plants were probed with antibodies
recognizing GF14 .epsilon. (lanes 1 and 3) and [I (lanes 2 and 4).
A clear reduction of these 14-3-3 isoforms is observed in the
starch-granule proteins of antisense plants. A 3-mg sample of
commercial corn starch was processed as described above and the
blot was probed with antibodies that recognize maize 14-3-3
proteins (lane 5), indicating the presence of 14-3-3 proteins in
starch grains from maize.
[0016] FIG. 5 shows consensus 14-3-3-binding sites in SSM coding
sequences. The phosphoserine/threonine-containing binding sequence
for 14-3-3 proteins is present in all known members ofthe SSIII
family listed in GenBank: SSIII from Vigna unguiculata (Vigna
SSIII, AJ225088), SSIII from Solanum tuberosum (Potato SSIII,
X94400 and X95759), SSEIII DU1 from Zea mays (Dull1 SS, AF023159),
SSIII from Triticum aestivum (Triticum SSIII, AF258608), SSIII from
Aegilops tauschii (Aegilops SSIII, AF258609), and apredicted SSIII
from Arabidopsis thaliana (At SSIII, AL021713). The 14-3-3 protein
consensus binding domain (BD) and the NR 14-3-3 binding domain are
shown for comparison.
[0017] FIG. 6 shows binding of 14-3-3 proteins to DU1 or DU1 -like
SS. Proteins isolated from digested starch were passed over an
anti-14-3-3 column and a control column. Bound proteins were
eluted, separated by electrophoresis, transferred to
nitrocellulose, and probed with antiserum to ZmSSIII DU1. The
anti-GF14 column retained the DU1 cross-reactive protein (largely
degraded from multiple processing steps) (lane 1), whereas the
negative control column did not (lane 2). Proteins extracted
directly from gelled starch were separated by electrophoresis and
transferred to nitrocellulose. Probing with biotinylated Zm GF14-12
identified a 14-3-3-binding protein of approximately 200 kDa (lane
3). Probing with antiserum to ZmSSIII DU1 labeled proteins of a
similar size (lane 4).
BRIEF DESCRIPTION OF THE SEQUENCES
[0018] SEQ ID NO. 1 is a polynucleotide sequence encoding 14-3-3
Epsilon protein.
[0019] SEQ ID NO. 2 is an amino acid sequence of a 14-3-3 Epsilon
protein encoded by the polynucleotide sequence shown in SEQ ID NO.
1.
[0020] SEQ ID NO. 3 is a polynucleotide sequence encoding 14-3-3 Mu
protein.
[0021] SEQ ID NO. 4 is an amino acid sequence of a 14-3-3 Mu
protein encoded by the polynucleotide sequence shown in SEQ ID NO.
3.
DETAILED DISCLOSURE OF THE INVENTION
[0022] The subject invention concerns materials and methods for
enhancing starch production in plants. Starch production is
enhanced, relative to levels observed in wildtype or control
plants, by reduction of the activity of plant 14-3-3 protein(s)
which subsequently results in increased accumulation of starch in
the plant. It has been discovered that the 14-3-3 proteins function
as inhibitory proteins in starch metabolism by shutting down starch
metabolism. It has also been discovered, based on the presence of
14-3-3 consensus binding domains and biochemical experiments, that
one target of the granule 14-3-3 proteins is the SSIII family of
enzymes.
[0023] One method for enhancing starch production in a plant
comprises introducing into the plant a polynucleotide of the
invention that comprises a nucleotide sequence that is antisense to
a 14-3-3 gene sequence in the plant. In one embodiment, a DNA
molecule encoding an RNA molecule that hybridizes to an MRNA
molecule that encodes a 14-3-3 protein is introduced into a plant.
The mRNA molecule may encode, for example, a 14-3-3 protein having
an amino acid sequence disclosed in SEQ ID NO. 2 or SEQ ID NO.
4.
[0024] Another method for enhancing starch production by inhibiting
14-3-3 protein expression in a plant comprises deleting or
replacing a functional 14-3-3 gene with a non-functional gene. The
plant in which the functional gene has been deleted or
non-functionalized is referred to as a "knockout" plant. General
methods for producing "knockout" plants are known and have been
described in the art (See, e.g., Krysan et al., 1996).
[0025] Methods for enhancing starch production in a plant
contemplated by the present invention also include direct
inhibition ofthe 14-3-3 proteins inplanta. In one embodiment, a
plant is transformed with a polynucleotide that encodes an
antibody, or a functional fragment thereof, e.g., an Fv portion of
the antibody, that binds to and blocks the function of the 14-3-3
proteins. In another embodiment, a plant is transformed with a
polynucleotide that provides an aptamer that can bind to and
inhibit the function of the 14-3-3 proteins in the plant. As used
herein, the term "aptamer" refers to a polynucleotide or
polypeptide that has the ability to bind with a high degree of
affinity and specificity to a target protein molecule. The
expression of antibodies or aptamers directed to 14-3-3 proteins
can be selected to be inducible or constitutive in the transformed
or transgenic plant.
[0026] The subject invention also concerns the "antisense"
polynucleotides ofthe invention that when introduced into a plant
cell can function to effectively reduce expression of the 14-3-3
proteins in a plant. In one embodiment, a polynucleotide of the
invention comprises a DNA molecule encoding an RNA molecule that
can hybridize to an MRNA molecule that encodes a 14-3-3 protein a
plant. The MRNA molecule may encode, for example, a 14-3-3 protein
having an amino acid sequence disclosed in SEQ ID NO. 2 or SEQ ID
NO. 4.
[0027] The subject invention also pertains to transformed and
transgenic plants that have polynucleotides that are antisense to
the 14-3-3 gene sequences expressed in the plant, wherein the
transformed and transgenic plants exhibit enhanced starch
production. In one embodiment, a DNA molecule encoding an RNA
molecule that hybridizes to an mRNA molecule that encodes a 14-3-3
protein is introduced into a plant. The mRNA molecule may encode,
for example, a 14-3-3 protein having an amino acid sequence
disclosed in SEQ ID NO. 2 or SEQ ID NO. 4.
[0028] The subject invention also pertains to "knockout" plants
which exhibit enhanced starch production, wherein the normal
functional 14-3-3 gene in the plant is deleted or replaced with a
non-functional form of the gene.
[0029] In one embodiment, a polynucleotide according to the present
invention is inserted into a suitable vector, and the recombinant
vector is used to transform a bacterium or other host which can
then be used to introduce the polynucleotide into a plant cell.
Agrobacterium containing a polynucleotide of the invention can be
used to transform plant cells with the polynucleotide according to
standard methods known in the art. Polynucleotides of the present
invention can also be introduced into plant cells using a biolistic
method (Carrer, 1995), as well as by other methods known in the
art, such as electroporation, microinjection and virus-mediated
transformation.
[0030] Transformed, transgenic and knockout plants produced
according to the present invention include both monocot and dicot
plants. Dicot plants contemplated within the scope of the present
invention include, for example, tobacco, potato, cabbage, soybeans,
and sweet potato. Monocot plants contemplated within the scope
ofthe invention include, for example, maize, wheat, barley, rice,
oats and other small cereals. In a preferred embodiment, the maize
is Zea mays. In an exemplified embodiment, the plant is
Arabidopsis.
[0031] Also contemplated within the scope ofthe invention is plant
material, including plant tissue, seeds, plant cells and
protoplasts, from the transformed, transgenic or "knockout" plants
of the present invention.
[0032] As used herein, the terms "nucleic acid" and "polynucleotide
sequence" refer to a deoxyribonucleotide or ribonucleotide polymer
in either single- or double-stranded form, and unless otherwise
limited, includes polynucleotides containing known analogs of
natural nucleotides that can function in a similar manner as
naturally-occurring nucleotides.
[0033] All patents, patent applications, provisional applications,
and publications referred to or cited herein are incorporated by
reference in their entirety to the extent they are not inconsistent
with the explicit teachings of this specification.
[0034] Following are examples which illustrate procedures for
practicing the invention. These examples should not be construed as
limiting. All percentages are by weight and all solvent mixture
proportions are by volume unless otherwise noted.
MATERIALS AND METHOD
[0035] Antisense GF14 Vector Construction and Transformation into
Arabidopsis. Clones for the Arabidopsis 14-3-3 proteins GF14
.epsilon. and GF14.mu., from yeast two-hybrid vectors (Wu et al.,
1997), were used as templates for PCR to produce XbaI cassettes
that were subsequently subdloned into the binary plant
transformation vector pBI121 (CLONTECH). Gene orientation was
determined by automated DNA sequencing on a Perkin-Elmer ABI 373A.
Clones containing the antisense GF14 gene orientation were
amplified in Escherichia coli INV.alpha.F' and used to transform
competent Agrobacterium tumefaciens strain EHA105 by the
freeze-thaw method (Holsters et al., 1978). The vector-harboring
Agrobacterium was used to transform Arabidopsis ecotype WS
seedlings by using vacuum infiltration, essentially as described by
Bechtold and Pelletier (Bechtold et al., 1998). Transformants were
screened on germination media plates using 40 .mu.g/ml kanamycin
selection as described previously (Daugherty et al., 1996). Seed
from positive transformants were selected through three successive
generations to ensure homozygous transgenic lines. A minimum of 12
antisense lines were generated for both GF14 .epsilon. and
GF14.mu..
[0036] Plant Growth. Arabidopsis plants were grown in constant
light at 22.degree. C. on germination media plates oriented in a
vertical position or in flats of Transplant mix A (Vergro, Tampa,
Fla.). Starch degradation experiments were done by transferring the
plants to dark and samples taken at three hour intervals.
[0037] Starch Analysis. Starch was visualized by Lugol's iodine
staining reagent (Sigma). Leaves from 10-day-old plants were
harvested and blanched in 80% (vol/vol) ethanol. After rinsing with
double-distilled water the leaves were stained with Lugol's reagent
and briefly destained with water. Stained plants and leaves were
photographed with an Olympus SZH10 stereo dissecting microscope and
DP10 digital camera.
[0038] Enzymatic measurement of starch in leaves was performed by
using a method adapted from Zeeman et al. (Zeeman et al., 1998).
Rosettes were harvested and weighed, then boiled in 80% ethanol.
After clearing, the samples were ground in a mortar and pestle in
80% ethanol and the crude starch pellet was recovered by
centrifugation at 5,000 rpm for 5 min in a Beckman JA20 rotor and
J2-21 centrifuge. The crude starch was resuspended in 80% ethanol
and repelleted two more times. The final pellet was dried and
resuspended in double-distilled water, then placed at 85.degree. C.
for 10 min. The starch solution was then digested with 3 mg/ml
amyloglucosidase and 20 units of amylase in 20 mM calcium acetate
pH 4.5 buffer for 24 h at 37.degree. C. The final concentration of
liberated glucose was determined by using a glucose oxidase assay
kit (Sigma).
[0039] Purified starch granules used for immunological and
biochemical studies were extracted from plants by using the
Mops-based protocol reported by Zeeman et al. (1998). Essentially,
whole plants minus the roots were ground in a Mops buffer system,
washed with SDS-containing buffer, and finally washed extensively
with deionized water. Yields were calculated on a milligrams of
isolated starch per gram fresh plant weight basis.
[0040] Relative amylose/amylopectin ratios from purified starch
granules were assayed by using iodine starch spectral analysis as
described by Konishi et al. (1985).
[0041] Immunolocalization and Blotting. Transmission electron
microscopy using GF14 isoform-specific polyclonal primary
antibodies and gold secondary antibodies was used to localize
14-3-3 proteins in the starch granules of Arabidopsis leaves by the
method previously described (Bihn et al., 1997). Starch granules
for immunoblotting were first treated with thermolysin to ensure
removal of surface-associated proteins as described by Mu-Foster et
al. (1996), and intrinsic starch granule proteins were separated by
SDS/PAGE and transferred to nitrocellulose membranes as described
(Sehnke et al., 2000).
[0042] 14-3-3 Protein-Binding Motif Analysis of Starch
Granule-Associated Proteins. A BLAST search (Altschul et al., 1997)
for the 14-3-3 phosphoserine/threonine-binding consensus motif
(RXXS/TXP) was conducted on the available plant starch-associated
protein sequences by using the National Institutes of Health BLAST
web server.
[0043] Immunocapture Experiments. Commercial corn starch (Argo,
Englewood Cliffs, N.J.) was used as a source of protein complexes
for the immunocapture experiments. The starch was first digested
with thermolysin to remove surface-associated proteins (Mu-Forster
et al., 1996), then washed and digested at 25.degree. C. with
.alpha.-amylase and amyloglucosidase in 100 mM Tris-acetate buffer,
pH 7.5, containing 100 mM KCl, 2.5 mM DTT, 10% (vol/vol) glycerol,
25 mM NaF, 3 mM CaCl.sub.2, and 0.1% BSA for 3 h by using a
protocol adapted from MacDonald and Preiss (MacDonald et al.,
1983). Undigested material was removed by ultracentrifugation in a
Beckman SW55 Ti rotor at 4.degree. C. at 50,000 rpm for 30 min.
Supernatant was transferred to a plastic conical tube and BSA was
added to a final concentration of 0.1%. The supernatant was passed
over anti-14-3-3 .epsilon.- and .mu.-conjugated Sepharose made from
CNBr-activated Sepharose (Amersham Pharmacia Biotech) and the
14-3-3 protein antisera IgG fractions (Sehnke et al., 2000). A
control column containing antibodies raised against the
transcriptional cofactor GIP1 (unpublished data) was used as a
negative control. The columns were loaded with the starch-derived
protein extract, then washed three times with phosphate-buffered
saline (PBS), pH 7.6, containing 25 mM NaF. The processed beads
were boiled for 1 min in 2.times.SDS/PAGE sample buffer. The beads
were removed by centrifugation and supernatant was loaded onto 10%
polyacrylamide gels before SDS/PAGE. The proteins were transferred
to nitrocellulose and blocked overnight with Blotto Tween (Harlow
et al., 1988). The membranes were probed with antiserum to the Zea
mays (Zm)SSmI DU1 (Cao et al., 1999). The membrane was washed and
incubated with horseradish peroxidase-conjugated antibodies to
rabbit IgG. Labeled bands were identified by the process of
chemiluminescence, using SuperSignal West Pico Chemiluminescent
Substrate according to the supplier's instructions (Pierce).
[0044] Biotinylated 14-3-3 Protein Overlay Experiments. To identify
corn starch proteins that are potential targets for 14-3-3 protein
binding, proteins from corn starch were separated by
electrophoresis and assayed by using a blot overlay procedure with
biotinylated recombinant 14-3-3 Zm GF14-12. Zm GF14-12 was
expressed in E. coli and purified by nickel-Sepharose
chromatography as described previously (de Vetten et al., 1994).
The protein was dialyzed against 100 mM sodium borate, pH 8.8,
overnight before addition of biotinamidocaproate
N-hydroxysuccinimide ester in DMSO at a ratio of 50 .mu.g of ester
per mg of protein. After 4 h at room temperature, the reaction was
terminated by the addition of 1 M ammonium chloride, pH 8.0. The
biotinylated 14-3-3 protein was dialyzed exhaustively against PBS
over the course of 2 days at 4.degree. C. Proteins from 10 mg of
corn starch boiled in SDS/PAGE sample buffer were separated by PAGE
and transferred to nitrocellulose, then incubated overnight at
4.degree. C. with biotinylated 14-3-3 protein in PBS containing 1%
BSA. The blot was washed three times with PBS/1% BSA and incubated
for 30 min with streptavidin-conjugated horseradish peroxidase
diluted in PBS/1% BSA. The blot was washed three additional times
and the 14-3-3-bound protein was identified by using
chemiluminescence as described above.
EXAMPLE 1
Transgenic Arabidopsis Plants Expressing Antisense cDNA
[0045] Transgenic Arabidopsis plants expressing antisense cDNA of
At 14-3-3s GF 14 .epsilon. and .mu.L, two members of the .epsilon.
subgroup of 14-3-3 proteins, displayed normal growth behavior but
demonstrated phenotypic changes relative to wild-type plants with
regard to starch accumulation in leaves. Although the absolute
level of starch present in the leaves of Arabidopsis depended upon
culture conditions and the lines examined, the leaves of plants
from all 12 GF14 .epsilon. and GF14.mu. antisense lines
consistently accumulated increased starch levels relative to leaves
of wild-type plants. Iodine staining indicated that the increased
starch accumulation was equally distributed throughout the leaves
of the antisense plants (FIGS. 1A-C). Quantitative measurements
ofthe starch present in the leaves of plants grown in constant
light revealed an approximately 2-fold increase in total starch
content in antisense plants over wild-type plants (28.+-.7 mg of
starch per g fresh weight in transgenic plants vs. 15.+-.3 mg of
starch per g fresh weight in wild-type plants). The extractable
starch from antisense plants was approximately 4-fold higher than
that from wild-type plants (43.+-.5 mg of starch per g fresh weight
vs. 9.+-.2 mg of starch per g fresh weight, respectively). Isolated
5 starch granules from antisense plants were used to evaluate the
absorption spectra of the iodine/starch complex, as an indicator of
unbranched and branched glucan ratios. The absorption spectrum
ofthe iodine/starch complex from antisense plants (FIG. 2, spectrum
B) was blue-shifted relative to the absorption spectrum ofthe
iodine/starch complex from wild-type plants (FIG. 2, spectrum A),
suggesting that the starch from antisense plants has an increase in
branched glucan content. This premise is further supported by the
observation that the percentage of gelatinizable starch from
antisense plants was reduced relative to that found in wild-type
plants (data not shown).
[0046] To determine whether altered degradation rates might be
responsible for the elevated starch accumulation in 14-3-3
antisense plants, plants were grown in constant light and harvested
after a dark period of 18 h. Iodine staining of leaves at the end
of the dark period was indistinguishable between wild-type (FIG.
1D) and antisense plants (FIG. 1E and 1F). To measure the rate of
starch breakdown, leaf samples were taken every 3 h after the
plants were placed in the dark. Wild-type plants degraded starch at
a rate of approximately 1 mg of starch per g fresh weight per h,
whereas the antisense plants cleared starch from their leaves at
rates of approximately 1.3 to 1.5 mg of starch per g fresh weight
per h. This result indicates that the starch degradation pathway is
fully functional in the antisense plants and suggests that reduced
negative regulation of starch biosynthesis is responsible for
increased starch in the 14-3-3 antisense plants. The 14-3-3
proteins would therefore appear to function as inhibitory proteins
in starch metabolism by normally shutting down starch biosynthesis,
thereby playing a key regulatory role in carbon allocation that is
similar to their role in nitrogen fixation.
EXAMPLE 2
Immunolocalization of 14-3-3 Proteins in Starch Granules
[0047] Antibodies to 14-3-3 proteins were used in an
immunolocalization electron microscopy experiment looking at starch
granules in the leaves of wild-type Arabidopsis. The inside of
chloroplast starch granules was densely decorated by antibodies
that recognize eight non-.epsilon. subgroup members (FIG. 3B).
Antibodies specific to GF14 .epsilon. also decorated the inside of
starch granules, but more sparsely (FIG. 3C). This limited amount
of .epsilon. in the starch granules of wild-type plants may explain
why the antisense plants displayed reduced levels of
starch-associated GF14 .epsilon., whereas the cytoplasmic levels of
.epsilon. remained reasonably normal (data not shown). These data
also indicate that non-.epsilon. 14-3-3 proteins may be involved in
starch biosynthesis, although no phenotypic data yet exist to
support this conclusion. The relationship among the 14-3-3 isoforms
present in starch grains, as well as the question ofwhether active
forms of 14-3-3 proteins exist as homodimers or heterodimers, is
not well established and therefore will need to be addressed in
future studies.
EXAMPLE 3
Western Blot Analysis of Reduction in 14-3-3 Protein in Plants
[0048] To confirm that 14-3-3 proteins are present within
chloroplast starch granules and that increased starch production is
a result of decreased 14-3-3 proteins, starch granules from
wild-type, GF14 .epsilon., and GF14.mu. antisense plant leaves were
biochemically analyzed for the presence of 14-3-3 proteins.
Purified starch granules were incubated with the protease
thermolysin to remove external proteins, washed, boiled in SDS/PAGE
sample buffer, and analyzed on SDS/PAGE by Western analysis with
antibodies specific to 14-3-3 proteins GF14 .epsilon. or .mu.
(Sehnke et al., 2000). Wild-type starch contained both GF14
.epsilon. and .mu. (FIG. 4 lanes 1 and 2), whereas antisense starch
did not contain detectable amounts of either (FIG. 4 lanes 3 and
4). This coregulated suppression is not surprising, as the identity
between cDNAs is approximately 70% and therefore both mRNAs are
reduced by antisense regulation in planta. Western analysis of
whole-leaf extracts did not demonstrate a pronounced decrease in
GF14 .epsilon. and .mu. proteins (data not shown). Starch
granule-specific reduction of GF14 .epsilon. and .mu. may be
reflective of a selection process for chloroplastid 14-3-3
proteins, perhaps pressured by an as-yet-uncharacterized import
mechanism (Sehnke et al., 2000). The presence of .epsilon. and .mu.
14-3-3 proteins in starch granules is significant in that they
appear essential for proper regulation of leaf starch biosynthesis
in Arabidopsis. In addition, commercial starch from maize also
possesses 14-3-3 proteins (FIG. 4 lane 5), suggesting that 14-3-3
protein regulation of starch synthesis is used by crops and occurs
in other plastids, such as amyloplasts, and is not limited to
photosynthetically active plastids.
EXAMPLE 4
Consensus 14-3-3-Binding Motif in SSEIII Coding Sequences
[0049] Although a chloroplast-localized 14-3-3 protein partner in
starch synthesis has not been reported, a search of all available
starch-related enzyme sequences for the consensus 14-3-3-binding
motif revealed the SSIII family as an obvious potential target
within the plastid (FIG. 5). SSIII members from potato,
Arabidopsis, Vigna unguiculata, Aegilops tauschii, Triticum
aestivum, and maize all contain a conserved hexapeptide motif very
similar to the 14-3-3 protein binding site of NR. This is the only
example of an entire family sharing such a highly conserved
potential binding site among the plastid enzyme sequences currently
available. It is interesting to note that SSIII is directly
involved in the production of amylopectin and has significant
control over other SS isoforms (Edwards et al. 1999), perhaps
explaining both starch accumulation and the qualitative shift in
branched glucan content observed in 14-3-3 antisense plants.
[0050] Immunocapture experiments with anti-GF14 column and proteins
isolated from processed corn starch were used to experimentally
determine whether starch granule 14-3-3 proteins associate directly
with SSIII. Commercial corn starch was chosen as a source of
proteins because of its bulk availability and antibodies to the
maize SSIII enzyme were available (Cao et al., 1999). SDS/PAGE and
Western analysis of immunocaptured proteins identified ZmSSIII DUI
as a starch 14-3-3 partner protein (FIG. 6). The molecular masses
of the captured protein bands were lower than the mass of intact
ZmSSIII DU1 (see below); however, this can be attributed to
breakdown of SSIII DU1 during the starch degradation process (Cao
et al., 1999). Although ZmSSIII DU1 was reported as primarily
located in the soluble fractions of kernel extracts, low levels of
ZmSSIII DU1 in starch were observed in starch granules (Cao et al.,
1999). To confirm that SSIII DU1 is present inside the corn starch
grains, and to avoid the degradation observed in the immunocapture
experiment, protease-treated commercial starch was boiled in
SDS/PAGE sample buffer, separated by electrophoresis, and
transferred to nitrocellulose. The blot was then probed with
biotinylated recombinant 14-3-3 protein, and bound bands were
detected by chemiluminescence (FIG. 6, lane 3). Biotinylated 14-3-3
protein bound to a protein of approximately 200 kDa, whose
migration corresponds to a main band recognized by ZmSSIII DU1
antibodies (FIG. 6, lane 4). These data provide correlative support
for an interaction between 14-3-3 proteins and DU1 or DU1-like
proteins within starch grains, but confirmation of the interaction
awaits detailed characterization of the protein complex.
[0051] The biological significance of choroplastid 14-3-3 proteins,
specifically the .epsilon. subgroup, in starch metabolism is
clearly demonstrated through the use of 14-3-3 antisense plants of
the present invention. Additionally, the increase in branched
glucans vs. nonbranched glucans in the antisense plants would seem
contrary to simply increasing the cytosolic flux of starch
precursors, as would be the effect of altered upstream regulation
of starch metabolism. Further experiments are necessary to confirm
the interaction between 14-3-3 proteins and SSEfis or other enzymes
regulated in this pathway, and the possibility of other plastid
enzymes being regulated by 14-3-3 proteins is not excluded.
However, the specific localization of the 14-3-3 proteins in the
starch granules should, in this instance, serve to limit the range
of possible 14-3-3 protein targets to those enzymes located within
starch-producing plastids.
[0052] These results show that starch composition and accumulation
can be directly regulated by plastid 14-3-3 proteins. The data
presented herein are consistent with a mechanism whereby starch
production in continuously illuminated plants is limited through
inactivation of SSs by phosphorylation and 14-3-3 protein binding.
Without 14-3-3 proteins to complete the inactivation step, starch
continues to accumulate beyond normal levels.
[0053] It should be understood that the examples and embodiments
described herein are for illustrative purposes only and that
various modifications or changes in light thereof will be suggested
to persons skilled in the art and are to be included within the
spirit and purview of this application and the scope of the
appended claims.
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Sequence CWU 1
1
4 1 1100 DNA Arabidopsis sp. CDS (49)..(810) 1 gcggccgcgt
cgacgaagga agaagaagaa gaagaagaag aaaaaact atg gag aat 57 Met Glu
Asn 1 gag agg gaa aag cag gtt tac ttg gct aag ctc tcc gag caa acc
gaa 105 Glu Arg Glu Lys Gln Val Tyr Leu Ala Lys Leu Ser Glu Gln Thr
Glu 5 10 15 aga tac gat gaa atg gtg gag gcg atg aag aaa gtt gct cag
ctt gat 153 Arg Tyr Asp Glu Met Val Glu Ala Met Lys Lys Val Ala Gln
Leu Asp 20 25 30 35 gtg gag cta act gtg gaa gag agg aat ctt gta tct
gta ggg tac aag 201 Val Glu Leu Thr Val Glu Glu Arg Asn Leu Val Ser
Val Gly Tyr Lys 40 45 50 aat gtg att ggt gca agg aga gca tca tgg
aga ata cta tct tcc att 249 Asn Val Ile Gly Ala Arg Arg Ala Ser Trp
Arg Ile Leu Ser Ser Ile 55 60 65 gag cag aag gaa gag tcc aag gga
aat gat gaa aat gtc aag agg ctt 297 Glu Gln Lys Glu Glu Ser Lys Gly
Asn Asp Glu Asn Val Lys Arg Leu 70 75 80 aag aat tat cgt aag aga
gtt gaa gat gag ctt gct aaa gtt tgt aat 345 Lys Asn Tyr Arg Lys Arg
Val Glu Asp Glu Leu Ala Lys Val Cys Asn 85 90 95 gac atc ttg tct
gtc att gat aag cat ctc att cca tcg tct aac gct 393 Asp Ile Leu Ser
Val Ile Asp Lys His Leu Ile Pro Ser Ser Asn Ala 100 105 110 115 gtg
gag tca act gtc ttt ttc tac aaa atg aaa gga gat tac tat cgc 441 Val
Glu Ser Thr Val Phe Phe Tyr Lys Met Lys Gly Asp Tyr Tyr Arg 120 125
130 tat ctt gcg gag ttc agt tct ggt gct gaa cgc aag gaa gct gca gat
489 Tyr Leu Ala Glu Phe Ser Ser Gly Ala Glu Arg Lys Glu Ala Ala Asp
135 140 145 cag tct ctt gaa gca tat aag gct gct gtt gct gct gca gag
aat ggt 537 Gln Ser Leu Glu Ala Tyr Lys Ala Ala Val Ala Ala Ala Glu
Asn Gly 150 155 160 ttg gca ccc aca cat cca gtt aga ctt ggc ttg gcg
ttg aac ttt tca 585 Leu Ala Pro Thr His Pro Val Arg Leu Gly Leu Ala
Leu Asn Phe Ser 165 170 175 gtt ttc tac tat gag atc ttg aac tct ccc
gaa agc gca tgc caa ttg 633 Val Phe Tyr Tyr Glu Ile Leu Asn Ser Pro
Glu Ser Ala Cys Gln Leu 180 185 190 195 gct aag caa gca ttc gat gat
gca att gct gaa ctt gac agc ctc aac 681 Ala Lys Gln Ala Phe Asp Asp
Ala Ile Ala Glu Leu Asp Ser Leu Asn 200 205 210 gag gaa tca tac aaa
gac agc act ctt att atg cag cta ctt aga gac 729 Glu Glu Ser Tyr Lys
Asp Ser Thr Leu Ile Met Gln Leu Leu Arg Asp 215 220 225 aat ctc acc
ttg tgg act tca gac ctt aat gag gaa gga gat gag aga 777 Asn Leu Thr
Leu Trp Thr Ser Asp Leu Asn Glu Glu Gly Asp Glu Arg 230 235 240 acc
aaa ggt gct gat gag cct caa gat gag aac taaatcctct gtgagaagag 830
Thr Lys Gly Ala Asp Glu Pro Gln Asp Glu Asn 245 250 aaacgactct
tgctgcatcc tgaatcttga agtgaagaca gtaagtgtcg ttgtttgtta 890
ctcgaatgtg taatttttaa tctatgtctt tcttgatggt gttttccaga ttcttgaact
950 tttcacaaca caacactgcg ttgcgtatct tcaaccctct tatgatgtgg
ttgaattctg 1010 ttttacgctt agtttgcttc ttttgttgtt gaattgagcc
agcaggcatg atttgggttt 1070 ttgtttatca gaatattagg cgtaaaaaaa 1100 2
254 PRT Arabidopsis sp. 2 Met Glu Asn Glu Arg Glu Lys Gln Val Tyr
Leu Ala Lys Leu Ser Glu 1 5 10 15 Gln Thr Glu Arg Tyr Asp Glu Met
Val Glu Ala Met Lys Lys Val Ala 20 25 30 Gln Leu Asp Val Glu Leu
Thr Val Glu Glu Arg Asn Leu Val Ser Val 35 40 45 Gly Tyr Lys Asn
Val Ile Gly Ala Arg Arg Ala Ser Trp Arg Ile Leu 50 55 60 Ser Ser
Ile Glu Gln Lys Glu Glu Ser Lys Gly Asn Asp Glu Asn Val 65 70 75 80
Lys Arg Leu Lys Asn Tyr Arg Lys Arg Val Glu Asp Glu Leu Ala Lys 85
90 95 Val Cys Asn Asp Ile Leu Ser Val Ile Asp Lys His Leu Ile Pro
Ser 100 105 110 Ser Asn Ala Val Glu Ser Thr Val Phe Phe Tyr Lys Met
Lys Gly Asp 115 120 125 Tyr Tyr Arg Tyr Leu Ala Glu Phe Ser Ser Gly
Ala Glu Arg Lys Glu 130 135 140 Ala Ala Asp Gln Ser Leu Glu Ala Tyr
Lys Ala Ala Val Ala Ala Ala 145 150 155 160 Glu Asn Gly Leu Ala Pro
Thr His Pro Val Arg Leu Gly Leu Ala Leu 165 170 175 Asn Phe Ser Val
Phe Tyr Tyr Glu Ile Leu Asn Ser Pro Glu Ser Ala 180 185 190 Cys Gln
Leu Ala Lys Gln Ala Phe Asp Asp Ala Ile Ala Glu Leu Asp 195 200 205
Ser Leu Asn Glu Glu Ser Tyr Lys Asp Ser Thr Leu Ile Met Gln Leu 210
215 220 Leu Arg Asp Asn Leu Thr Leu Trp Thr Ser Asp Leu Asn Glu Glu
Gly 225 230 235 240 Asp Glu Arg Thr Lys Gly Ala Asp Glu Pro Gln Asp
Glu Asn 245 250 3 1113 DNA Arabidopsis sp. CDS (70)..(858) 3
agtaatttag gtcgtcaaaa gctttggaat ttgatacttt tgatttttcg agaatcttga
60 aaatcagtc atg ggt tct gga aaa gag cgt gac act ttc gtc tac ctc
gct 111 Met Gly Ser Gly Lys Glu Arg Asp Thr Phe Val Tyr Leu Ala 1 5
10 aag ctc tct gag caa gct gag cgt tat gaa gaa atg gtg gaa tca atg
159 Lys Leu Ser Glu Gln Ala Glu Arg Tyr Glu Glu Met Val Glu Ser Met
15 20 25 30 aaa agt gtt gcg aaa ttg aat gtt gat ctg acg gtg gaa gag
agg aac 207 Lys Ser Val Ala Lys Leu Asn Val Asp Leu Thr Val Glu Glu
Arg Asn 35 40 45 tta ctc tct gtg ggt tac aag aac gtg att ggt tca
agg aga gct tcg 255 Leu Leu Ser Val Gly Tyr Lys Asn Val Ile Gly Ser
Arg Arg Ala Ser 50 55 60 tgg agg atc ttc tcg tcg att gaa caa aag
gaa gca gtg aaa ggg aat 303 Trp Arg Ile Phe Ser Ser Ile Glu Gln Lys
Glu Ala Val Lys Gly Asn 65 70 75 gat gtt aat gta aag agg atc aaa
gag tat atg gag aag gtt gag tta 351 Asp Val Asn Val Lys Arg Ile Lys
Glu Tyr Met Glu Lys Val Glu Leu 80 85 90 gag ctt tct aac ata tgc
att gat att atg tct gtc tta gat gag cat 399 Glu Leu Ser Asn Ile Cys
Ile Asp Ile Met Ser Val Leu Asp Glu His 95 100 105 110 ctc att cct
tcg gct tcc gag ggt gaa tct act gtc ttc ttc aac aag 447 Leu Ile Pro
Ser Ala Ser Glu Gly Glu Ser Thr Val Phe Phe Asn Lys 115 120 125 atg
aaa ggt gac tat tac cgc tat ctt gct gag ttc aaa tca ggg aac 495 Met
Lys Gly Asp Tyr Tyr Arg Tyr Leu Ala Glu Phe Lys Ser Gly Asn 130 135
140 gag agg aaa gag gct gct gat cag tct ttg aaa gcc tat gag att gct
543 Glu Arg Lys Glu Ala Ala Asp Gln Ser Leu Lys Ala Tyr Glu Ile Ala
145 150 155 act act gct gct gag gct aag ctc cct cca aca cac cct atc
aga ttg 591 Thr Thr Ala Ala Glu Ala Lys Leu Pro Pro Thr His Pro Ile
Arg Leu 160 165 170 ggt ttg gct ttg aat ttc tct gtc ttc tac tac gag
atc atg aac gca 639 Gly Leu Ala Leu Asn Phe Ser Val Phe Tyr Tyr Glu
Ile Met Asn Ala 175 180 185 190 cct gaa agg gca tgt cac ctt gct aag
cag gcg ttc gat gaa gct atc 687 Pro Glu Arg Ala Cys His Leu Ala Lys
Gln Ala Phe Asp Glu Ala Ile 195 200 205 tca gag ctt gac act ctg agc
gag gaa tcc tac aaa gat agc acc tta 735 Ser Glu Leu Asp Thr Leu Ser
Glu Glu Ser Tyr Lys Asp Ser Thr Leu 210 215 220 ata atg caa ctc ctt
agg gac aat ctg acc ttg tgg act tct gac atc 783 Ile Met Gln Leu Leu
Arg Asp Asn Leu Thr Leu Trp Thr Ser Asp Ile 225 230 235 tca gaa gaa
gga gga gac gat gct cat aag acg aat ggt tct gcc aaa 831 Ser Glu Glu
Gly Gly Asp Asp Ala His Lys Thr Asn Gly Ser Ala Lys 240 245 250 cct
ggt gct ggt gga gac gat gca gag tgatatgata tgtgtgcacc 878 Pro Gly
Ala Gly Gly Asp Asp Ala Glu 255 260 tggacaatat gtttcaagaa
ctgaatgtgc ggtgaataat agtgaaaagt agagtttctc 938 tgttccctat
atcatgattg tctatgttac ttgtactctg gtttagccct aaatgtctct 998
ctggtttgaa tgtattgcat gcctgtctca ggacactctt atttgtaatt cactactgtc
1058 gtcctactat ctatccttat ggatccaatc ttgaaactaa aaaaaaaaaa aaaaa
1113 4 263 PRT Arabidopsis sp. 4 Met Gly Ser Gly Lys Glu Arg Asp
Thr Phe Val Tyr Leu Ala Lys Leu 1 5 10 15 Ser Glu Gln Ala Glu Arg
Tyr Glu Glu Met Val Glu Ser Met Lys Ser 20 25 30 Val Ala Lys Leu
Asn Val Asp Leu Thr Val Glu Glu Arg Asn Leu Leu 35 40 45 Ser Val
Gly Tyr Lys Asn Val Ile Gly Ser Arg Arg Ala Ser Trp Arg 50 55 60
Ile Phe Ser Ser Ile Glu Gln Lys Glu Ala Val Lys Gly Asn Asp Val 65
70 75 80 Asn Val Lys Arg Ile Lys Glu Tyr Met Glu Lys Val Glu Leu
Glu Leu 85 90 95 Ser Asn Ile Cys Ile Asp Ile Met Ser Val Leu Asp
Glu His Leu Ile 100 105 110 Pro Ser Ala Ser Glu Gly Glu Ser Thr Val
Phe Phe Asn Lys Met Lys 115 120 125 Gly Asp Tyr Tyr Arg Tyr Leu Ala
Glu Phe Lys Ser Gly Asn Glu Arg 130 135 140 Lys Glu Ala Ala Asp Gln
Ser Leu Lys Ala Tyr Glu Ile Ala Thr Thr 145 150 155 160 Ala Ala Glu
Ala Lys Leu Pro Pro Thr His Pro Ile Arg Leu Gly Leu 165 170 175 Ala
Leu Asn Phe Ser Val Phe Tyr Tyr Glu Ile Met Asn Ala Pro Glu 180 185
190 Arg Ala Cys His Leu Ala Lys Gln Ala Phe Asp Glu Ala Ile Ser Glu
195 200 205 Leu Asp Thr Leu Ser Glu Glu Ser Tyr Lys Asp Ser Thr Leu
Ile Met 210 215 220 Gln Leu Leu Arg Asp Asn Leu Thr Leu Trp Thr Ser
Asp Ile Ser Glu 225 230 235 240 Glu Gly Gly Asp Asp Ala His Lys Thr
Asn Gly Ser Ala Lys Pro Gly 245 250 255 Ala Gly Gly Asp Asp Ala Glu
260
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