Molecular bases that ensure genomic inheritance through successive generations

确保基因组遗传代代相传的分子基础

基本信息

批准号：
17207011
负责人：
KISHIMOTO Takeo
金额：
$ 31.45万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

Based on the cell cycle control and the nuclear formation, molecular mechanisms that ensure genomic inheritance through successive generations have been studied in oocytes and eggs of starfish and frog.1. Meiotic reinitiation : We had previously showed that the signaling pathway that leads to meiotic reinitiation in starfish oocytes is composed of the putative receptor for maturation-inducing hormone, 1-MeAde/hetero-trimeric G-protein/PI3-kinase/Akt/cyclin B-Cdc2/Plk1. Here, we tried to isolate the 1-MeAde receptor using affinity ferrite beads. Three peptides of 42, 92 and 97 kDa which should possibly consitute the receptor were identified. In addition, we found that activation of Aurora, a mitotic kinase, completely depends on activation of cyclin B-Cdc2 at meiotic reinitiation in starfish oocytes ; and that a single type of starfish Aurora exhibits both functions of Aurora A and B, each of which has distinct functions in HeLa cells.2. Meiotic metaphase-II arrest and its release : In Xenopus oocytes, we demonstrated that meta-II arrest is induced by direct phosphorylation of Erp1 with p9ORsk, which enhances both stability of Erp1 and its inhibitory activity against APC/C, thereby preventing the APC/C-mediated degradation of cyclin B.At release from meta-II arrest, we showed that in addition to previously known CaMKII, transient activation of calcineurin is required for Erp1 degradation and restart of the cell cycle.3. Formation of male and female pronuclei : In immature Xenopus oocytes, we found that importin α-mediated nuclear transport is suppressed due to its trapping into annulate lamellae, and that the trapping is cancelled at meiotic reinitiation. This should contribute to acqusition of the pronuclear formation ability during meiotic maturation. Further, we showed in starfish eggs that pronuclear congression and fusion after fertilization do not depend on the cell cycle progression.

基于细胞周期控制和核形成，在海星和青蛙的卵母细胞和卵中研究了确保基因组遗传的分子机制。 1. 减数分裂重新启动：我们之前已经表明，导致减数分裂重新启动的信号通路。海星卵母细胞中由成熟诱导激素的推定受体 1-MeAde/异源三聚体 G 蛋白/PI3 激酶/Akt/细胞周期蛋白组成在这里，我们尝试使用亲和铁氧体珠分离 1-MeAde 受体，这三种肽可能构成受体。此外，我们发现 Aurora 的激活。一种有丝分裂激酶，完全依赖于海星卵母细胞减数分裂重新启动时细胞周期蛋白 B-Cdc2 的激活，并且单一类型的海星 Aurora 表现出这两种功能； Aurora A 和 B 的功能，各自在 HeLa 细胞中具有不同的功能。 2. 在爪蟾卵母细胞中，我们证明，meta-II 停滞是通过 p9ORsk 直接磷酸化 Erp1 诱导的。增强 Erp1 的稳定性及其对 APC/C 的抑制活性，从而防止 APC/C 介导的细胞周期蛋白 B 降解。在从 meta-II 停滞释放时，我们发现除了先前已知的CaMKII，钙调神经磷酸酶的瞬时激活是 Erp1 降解和细胞周期重新启动所必需的。 3. 在未成熟的非洲爪蟾卵母细胞中，我们发现输入蛋白 α 介导的核转运由于其被捕获到环形片层中而受到抑制。，并且在减数分裂重新启动时捕获被取消，这应该有助于在减数分裂成熟期间获得原核形成能力。在海星卵中表明，受精后的原核会聚和融合不依赖于细胞周期进程。