1996 Fiscal Year Final Research Report Summary
Analysis of regulatory mechanisms of meiosis in mouse
| Project/Area Number |
07680752
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Molecular biology
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| Research Institution | University of Tokyo |
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Principal Investigator |
IMAI Yoshiyuki University of Tokyo, School of Science, Research Associate, 大学院・理学系研究科, 助手 (80260040)
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| Project Period (FY) |
1995 – 1996
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| Keywords | meiosis / mouse / fission yeast |
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| Research Abstract |
1. I isolated mouse genes which transcomplemented Schizosaccharomyces pombe mutants defective in meiosis. The S.pombe mei2 gene encodes an RNA-binding protein which is essential for initiation of meiosis and associates with the meiRNA encoded by sme2.12 mouse genes complemented the mei2 and/or sme2 mutations. One of the genes (clone number #MA6) is transcribed abundantly in testis and encodes a protein homologous to bovine poly A binding protein II.The product of this gene was shown to localize to the nucleus in the spermatocytes. 2. The S.Pombe mesl is essential for progression of meiosis II.Mouse proto-oncogene c-cbl, and genes encoding actin, tubulin, and dynein transcomplemented the mesl mutation. 3.11 genetic loci, named smsll-smsll, recessive mutations of which suppress the mesl mutation, were identified in S.pombe. Several sms mutations were suppressed by overexpression of dis2, that encodes type I protein phosphatase. Three multi-copy suppressors of mesl were identified, namely, nda2 that encodes a-tubulin, benl that encodes b-tubulin, and slpl, that is suggested to be involved in the restart of cell cycle progression after the completion of DNA repair. 4. The S.pombe mam4 gene encodes farnesyl cysteine carboxyl methyltransferase which modify various proteins including Ras superfamily and mating pheromone M-factor. I isolated a homolog of mam4 from Xenopus laevis (Xmam4) by transcomplementation of S.pombe mam4. Xmam4 is the first example of a farnesyl cysteine carboxylmetryltransferase gene from a eukaryote higher than yeast. Recently, a mouse homolog of Xmam4 was identified by EST (expressed sequence tags) project, suggesting that this enzyme is conserved from lower eukaryotes to mammals. 5. In S.pombe, nuclear reorganization switching the position of centromeres and telomeres take place upon entering meiosis. Fluorescence in situ hybridization revealed that the mating pheromone signaling causes clustering of telomeres near the SPB (spindle pole body).
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