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Regulatory Mechanisms of Cell Division in Early Development

早期发育中细胞分裂的调控机制

基本信息

批准号：
01304005
负责人：
KATAGIRI Chiaki
金额：
$ 7.23万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Co-operative Research (A)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

项目摘要

A technique was devised to isolate a large number of germinal vesicles (GV) from the starfish oocytes, with which the system was established for biochemical analyses of cyclic cytoplasmic activities that accompany cell cycles during maturation and cleavage divisions. Tha maturation promoting factor (MPF) in starfish oocytes is defined as the histone H1 kinase activity which is based on the phosphorylated cdc2 protein associated with the cyclin. The cyclic proteolysis of cyclin results in cessation of M-phase in cell cycles. Remodeling of nuclear basic proteins during fertilization and cleavage stages was analyzed by the cell-free system employing lysolecithin-permeabilized sperm nuclei incubated in the cytosls of amphibian eggs. During pronulcear formation, the protamines are quickly removed non-enzymatically by the nucleoplasmin derived from the GV, followed by an addition of nucleosomal core histones and a subtype of histone H1 (H1X) which is specific to the cleavage stage nuclear chromatin. The contractile ring occurring during cytokinesis of sea urchin eggs is formed by an organized assembly of actin fibers which is based on the phosphorylated myosin light chains. Of several protein s that are thought to participate in regulation of contractile ring formation, determinations were made of the binding site on the actin molecule of depactin as well as the primary structure of profilin, an inhibitor of G-actin polymerization. Both the cleavage furrow-inducing activity and the furrow formation in the amphibian eggs were inhibited by colchicine and vinblastine, suggesting a direct involvement of microtubule system in the formation of contractile system of the cleavage furrow.

设计了一种从海星卵母细胞中分离大量生发囊泡（GV）的技术，建立了用于分析细胞周期中伴随细胞成熟和卵裂分裂的细胞质周期活动的生化分析系统。海星卵母细胞中的成熟促进因子（MPF）被定义为基于与细胞周期蛋白相关的磷酸化cdc 2蛋白的组蛋白H1激酶活性。细胞周期蛋白的周期性蛋白水解导致细胞周期中M期的停止。用溶血卵磷脂渗透的精子核在无细胞体系中孵育，研究了受精和卵裂过程中核碱性蛋白的重构。在原核形成过程中，鱼精蛋白被来自GV的核质蛋白以非酶促方式快速去除，随后加入核小体核心组蛋白和对裂解阶段核染色质特异的组蛋白H1亚型（H1 X）。在海胆卵胞质分裂期间发生的收缩环是由基于磷酸化肌球蛋白轻链的肌动蛋白纤维的有组织组装形成的。在被认为参与调节收缩环形成的几种蛋白质中，确定了depactin的肌动蛋白分子上的结合位点以及profilin的一级结构，profilin是G-肌动蛋白聚合的抑制剂。秋水仙碱和长春碱对卵裂沟的诱导活性和卵裂沟的形成均有抑制作用，表明微管系统直接参与卵裂沟收缩系统的形成。