| Project/Area Number |
09440262
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
植物生理
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
NAITO Satoshi Fac.of Agr., Hokkaido Univ., Prof., 農学部, 教授 (20164105)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIKAWA Masayuki Fac.of Agr., Hokkaido Univ., Assoc.Prof., 農学部, 助教授 (70192482)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥10,500,000 (Direct Cost: ¥10,500,000)
Fiscal Year 1998: ¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 1997: ¥5,500,000 (Direct Cost: ¥5,500,000)
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| Keywords | Arabidopsis thaliana / methionine / amino acid synthesis / mRNA accumulation / systathionine gamma-synthase / mutant / メチオニン生合成 / 突然変異株 / エチオニン耐性 / シスタチオニンγ-シンターゼ / シスタチオニンγーシンターゼ |
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| Research Abstract |
In order to know the molecular mechanism of the regulation of methionine biosynthesis in higher plants, Arabidopsis mutants, mtol, that over-accumulate soluble methionine was studied. The mtol mutant plants accumulate up to 40-fold higher concentrations of soluble methionine in young rosette leaves, whereas the accumulation of other amino acids of the aspartate family were not appreciably different from wild-type plants. Therefore, the biochemical lesion carried by the mtol mutant was suggested to be resided in one of the later steps in the pathway. Accumulation of mRNA for cystathionine gamma-synthase (CGS), which has been suggested to be a key enzyme in methionine biosynthesis, was higher in mtol mutant as compared to wild-type plants. When wild0type plants were cultured in the presence of methionine, the accumulation of CGS mRNA was reduced, whereas no such effect was observed in the mtol mutant plants. Therefore it was suggested that wild-type plants have a mechanism to down-regulate the accumulation of CGS mRNA in response to methionine excess conditions. Genetic mapping and sequence analyses revealed that the mtol mutant bears mutations in the coding region of CGS gene. Transient expression analyses indicated that the mtol mutation affects the stability of CGS mRNA.
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