1991 Fiscal Year Final Research Report Summary
Molecular mechanisms of the regulation of cell proliferation in higher plants.
| Project/Area Number |
02454007
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
植物生理学
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| Research Institution | Tohoku University |
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Principal Investigator |
KOMAMINE Atsushi Biological Institute, Faculty of Science Tohoku University, Professor, 理学部, 教授 (90011494)
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| Project Period (FY) |
1990 – 1991
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| Keywords | higher plants / yeast / cell cycle / gene expression / synchronous cultures / auxin / molecular biology |
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| Research Abstract |
Several cell-cycle specific cDNAs were isolated in the two different synchronous cell division systems of Catharanthus roseus cells. In one system, synchronized cell division is induced by double phosphate-starvation method and in the other it is induced by auxin starvation and subsequent addition of auxin. One of the genes isolated from synchronous culture induced by double phosphate-starvation method, which we refer as cycO7, was characterized in detail. cycO7 mRNA was detected specifically in cells of the S phase in both synchronous cell division systems. The expression of cycO7 was found specifically in the rapedly growing cells, both in cultured plant cells and intact plants., It was revealed that many other plant species and also yeasts contained the genes that were homologous to cycO7. We analyzed the gene function in budding yeast by site-directed gene disruption, and demonstrated that the genes homologous to cycO7 is essential for cell proliferation of yeasts. The protein encoded by cycO7 was found to be localized in nuclei of the cells which were dividing rapidly. Another cDNA clone isolated from synchronous culture induced by auxin starvation, named as cycl9, was also characterized. The pattern of expression of cycl9 was quite similar to that of cycO7. cycl9 was expressed also in the S phase in the synchronous cultures. The nucleotide sequence of cycl9 cDNA was similar to that of heat shock protein 90 (HSP90). The function of this gene has not identified clearly. These findings led us to hypothesize that HSP90 played an important role in the cell proliferation in higher plant cells.
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