| Project/Area Number |
59440002
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
植物形態・分類学
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| Research Institution | Okazaki National Research Institutes |
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Principal Investigator |
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| Project Period (FY) |
1984 – 1985
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| Project Status |
Completed (Fiscal Year 1985)
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| Budget Amount *help |
¥37,500,000 (Direct Cost: ¥37,500,000)
Fiscal Year 1985: ¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1984: ¥35,000,000 (Direct Cost: ¥35,000,000)
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| Keywords | maternal inheritance / Chlamydomonas / fluorescence fluorimetory / chloroplast / nuclease C |
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| Research Abstract |
Attempts to isolate nucleases from young zygotes of C. reinhardtii showed that extracted nucleases required the presence of Ca++ for full activation and are thus call Nuclease C. They show polymorphism and are composed of six molecules with molecular masses of 16K,18K,21K,22K,and 26K. Nucleases with similar properties have been found in other algae. Since preferentail destruction of cp-nuclei of male origin is inhibited by EGTA. Nuclease C may be responsible for the preferential digestion of cpDNA in vivo. I proposed a mechanism for the regulation of maternal inhericance of cpDNA in young zygotes called as the active digestion hypothesis. Female gametes have the ability to protect their cpDNA against Nuclease C during gametogenesis by changing the domains surrounding female cpDNA. Soon after mating of male and female gametes, specific mRNAs are synthesized in a cell nucleus of female origin in the newly formed zygote. Then proteins which are coded by the mRNAs are synthesized de novo in the cytoplasm and directly or indirectly activated Nuclease C. Nuclease C preferentially digests cpDNA in the chloroplast of male origin. Since cpDNA of female origin remains, and is transmitted into progeny, maternal inheritance occurs.
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