1997 Fiscal Year Final Research Report Summary
VACUOLAR PROCESSING SYSTEM IN HIGHER PLANTS
| Project/Area Number |
08454262
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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 | (NATIONAL INSTITUTE FOR BASIC BIOLOGY) Okazaki National Research Institutes |
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Principal Investigator |
HARA Ikuko NATIONAL INSTITUTE FOR BASIC BIOLOGY,DEPARTMENT OF CELL BIOLOGY,ASSOCIATE PROFESSOR, 基礎生物学研究所, 助教授 (00241232)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Vacuolar processing enzyme / Senescence / Cysteine proteinase / Arabidopsis / Vacuoles / Stress / 液胞 / 抵抗性遺伝子 |
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| Research Abstract |
Vacuolar processing enzymes (VPE) are cysteine proteinases responsible for maturation of various vacuolar proteins in plants. A larger precursor to VPE synthesized on rough endoplasmic reticulum is converted to an active enzyme in the vacuoles. We expressed a precursor to castor bean VPE in a pep4 strain of the yeast Saccharomyces cerevisiate to examine the mechanism of activation of VPE.Our findings suggest that an inactive VPE precursor synthesized on the endoplasmic reticulum is transported to the vacuoles in the yeast cells and then processed to make an active VPE by self-catalytic proteolysis within the vacuoles.
Arabidopsis has three vacuolar processing enzymes (VPEs). The promoter of the betaVPE gene was found to direct the expression of the beta-glucuronidase reporter gene in the seeds, the pollen and the root tip of a transgenic Arabidopsis. On the other hand, the promoters of both the alphaVPE and gammaVPE genes were found to direct remarkably the eression in senescent tissue. Treatment with wounding, ethylene and salicylic acid induced the gene expression of the alphaVPE and gammaVPE genes, while jasmonate slightly induced that of the gammaVPE.Taken together, the results suggest that vegetative VPEs might regulate the activation of some functional proteins in the vegetative vacuoles.
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