2021 Fiscal Year Final Research Report
Regulation of light-dependent synthesis of L-ascorbate in plants
Project/Area Number |
19K06702
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Multi-year Fund |
Section | 一般 |
Review Section |
Basic Section 44030:Plant molecular biology and physiology-related
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Research Institution | Saitama University |
Principal Investigator |
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Project Period (FY) |
2019-04-01 – 2022-03-31
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Keywords | ビタミンC / 糖ヌクレオチド / GDP-マンノース / 環境ストレス / タンパク質分解制御 |
Outline of Final Research Achievements |
L-Ascorbic acid is synthesized via nucleotide sugar GDP-mannose (GDP-Man) and GDP-L-galactose in plants. VTC1 is a GDP-mannose pyrophosphorylase catalyzing the conversion from Man 1-P to GDP-Man, a rate-determining step in this pathway. KONJAC1 (KJC1) protein has been identified as a factor increasing VTC1 activity in Arabidopsis. To examine a function of KJC1 in the stability of VTC1, transgenic Arabidopsis harboring FLAG-fused genomic VTC1 gene was generated. In kjc1 mutant, the amount of FLAG-VTC1 protien was reduced to less than 10% of wild-type Arabidopsis, corresponding to VTC1 acticity. A native form of VTC1 was extracted from Arabidopsis and applied to size-exclusion chromatography. While high VTC1 activity was detected in the high-molecular weight fraction from the wild-type plant, the activity was not detected in the fraction from kjc1 mutant. These results suggest that KJC1 protects VTC1 from protein degradation by forming a large complex in Arabidopsis.
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Free Research Field |
植物糖鎖生物学
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Academic Significance and Societal Importance of the Research Achievements |
ビタミンCは植物細胞内の酸化還元レベルの調節に極めて重要な分子であり、体内でビタミンCを合成できない我々ヒトにとっては欠くことができない栄養素の一つである。これまでにビタミンCの合成に関わる各種の酵素が同定されているが、合成の調節機構はいまだに不明な点が多い。特に遺伝子発現後のタンパク質レベルの調節機構がわかっていなかった。本研究は、VTC1の相互作用因子KJC1により、VTC1が分解から守られていることがわかり、ビタミンC合成制御機構の一端を明らかにした。
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