C-MOS FORCES THE MITOTIC CELL CYCLE TO UNDERGO MEIOSIS II TO PRODUCE HAPLOID GAMATES
| Project/Area Number |
11680717
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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 |
Developmental biology
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
TACHIBANA Kazunori Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Assistant Professor, 大学院・生命理工学研究科, 助手 (60212031)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1999: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | c-Mos / MAP kinase / activation / DNA replication / oocyte maturation / meiosis / cell cycle / parthenogenesis / MOS |
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| Research Abstract |
We have studied the functions of c-Mos proto oncogene product in starfish oocyte maturation and early embryonic cell cycles. The meiotic cycle reduces ploidy through two consecutive M phases, meiosis I and meiosis II, without an intervening S phase. To maintain ploidy through successive generations, meiosis must be followed by mitosis after the recovery of diploidy by fertilization. However, the coordination from meiotic to mitotic cycle is still unclear. Mos, the c-mos protooncogene product, is a key regulator of meiosis in vertebrates. In contrast to the previous observation that Mos, functions only in vertebrate oocytes that arrest at meiotic metaphase II, here we isolate the first invertebrate mos from starfish and show that Mos functions also in starfish oocytes that arrest after the completion of meiosis II but not at metaphase II.In the absence of Mos meiosis I is followed directly by repeated embryonic mitotic cycles, and its reinstatement restores meiosis II and subsequent cell cycle arrest. These observations imply that after meiosis I, oocytes have a competence to progress through the embryonic mitotic cycle, but that Mos diverts the cell cycle to execute meiosis II and remains to restrain the return to the mitotic cycle. We propose that a role of Mos that is conserved in invertebrate and vertebrate oocytes is not to support metaphase II arrest but to prevent the meiotic/mitotic conversion after meiosis I until fertilization, directing meiosis II to ensure the reduction of ploidy.
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Report
(3 results)
Research Products
(7 results)
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[Publications] Nishiyama, A., Tachibana, K., Igarashi, Y., Yasuda, H., Tanahashi, N., Tanaka, K., Ohsumi, K., and Kishimoto, T.: "A non-proteolytic function of the proteasome is required for the dissociation of Cdc 2 and cyclin B at the end of M-phase."Genes Dev.. 196. 39-53 (2000)
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