2003 Fiscal Year Final Research Report Summary
Analyses for the regulation of mammalian oocyte/early embryo specific cell cycle which is aimed for introduction into somatic cells
| Project/Area Number |
14360173
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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 |
Basic veterinary science/Basic zootechnical science
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| Research Institution | The University of Tokyo |
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Principal Investigator |
NAITO Hideaki The University of Tokyo, Graduate School of Agricultural and Life Sciences, Associate Professor, 大学院・農学生命科学研究科, 助教授 (20188858)
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| Co-Investigator(Kenkyū-buntansha) |
CHIDA Kazuhiro The University of Tokyo, Graduate School of Agricultural and Life Sciences, Professor, 大学院・農学生命科学研究科, 教授 (00192188)
AOKI Fugaku The University of Tokyo, Graduate School of Frontier Sciences, Associate Professor, 大学院・新領域創成科学研究科, 助教授 (20175160)
TOJO Hideaki The University of Tokyo, Graduate School of Agricultural and Life Sciences, Professor, 大学院・農学生命科学研究科, 教授 (20041668)
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| Project Period (FY) |
2002 – 2003
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| Keywords | Mammalian ova / Meiosis / Early embryo development / Cell cycle / MPF / Rb / Mos / antisense RNA |
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| Research Abstract |
I analyzed the regulation mechanisms of mammalian oocytelearly embryo specific cell cycle, aiming for the introduction of their cell cycle into somatic cells. I found the following new mechanisms in oocyte meiosis (1, 2) and early embryo cleavage (3, 4).
(1)The large nucleus in immature oocyte, germinal vesicle (GV), was required for the meiosis specific consecutive two M-phases without S-phase, and the oocyte entered into S-phase after only one M-phase as somatic cells when GV was removed. This failure was attributed to the degradation of cyclin B during second meiosis.
(2)The suppression of MAPK activity by injection of anatisense-RNA of MAPK activator induced the significant increase of cyclin B accumulation in porcine oocytes.
(3)The accelerated cell cycle of early embryo cleavage was due to the absence of Rb protein, which inhibits the G1/S transition, in early embryos and, therefore, next S-phase started immediately after M-phase. The expression of Rb in early embryos by the injection of Rb-expression vector resulted the appearance of G1-phase after M-phase.
(4)The artificial activation or inhibition of MA.PK by injecting constitutively active or inactive mutant MAPK activator had no effect on the early embryo cleavage, suggesting the dispensability of MAPK for cleavage and the importance of Rb absence.
These findings might be useful for the induction of meiosis into somatic cells and production of haploid cells artificially.
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