Mechanism of contractile ring formation during cytokinesis

胞质分裂过程中收缩环形成的机制

基本信息

批准号：
12490008
负责人：
MABUCHI Issei
金额：
$ 8.9万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12490008/
关键词：
cytokinesis contractile ring actin myosin small G-proteins actin-modulating proteins phosphorylation cleavage furrow

项目摘要

We analyzed mechanism of formation of the contractile ring using the fission yeast Schizosaccharomyces pombe and Xenopus laevis eggs. It seemed that the contractile ring in fission yeast cells are formed from F-actin cables which accumulate at the medial region of the cell during nuclear division. First, the aster-like structure consisting of F-actin cables is formed during prophase near the spindle pole body, and then the leading cable elongates and encircles the cell. F-actin cables accumulated around this region are fused to this leading cable so that the contractile ring is estabIished. Cdc12 plays a role in elongation of the leading cable, while Cdc15 plays a role in the fusion of the F-actin cables to the leading cable.The small G-protein Rho has been considered to be an important component member of the cleavage signaling pathway. We analyzed function of Rho proteins in fission yeast, and found a novel G-protein Rho3. Rho3 is localized to the cell membrane. It was found that a novel formin family protein For3 is present downstream of either Rho3 or Cdc42. Rho3 and For3 controls both actin cytoskeleton and microtubules, and thereby regulate shape of the cell and position of cytokinesis.Role of microtubules in formation of the contractile ring in Xenopus eggs was analyzed. Disruption of microtubules by microtubule poisons did not interfere with contraction of the contractile ring, but interfered with its formation. We also found that the microtubules emanated from the both poles link with each other beneath the cleavage furrow. We tested a possibility that Ca ions play a role in cleavage signaling by analyzing Ca release around the cleavage furrow. Neither Ca waves nor small Ca releases such as Ca puffs or Ca blips were found at the leading edge of the cleavage furrow.

我们使用裂变酵母菌酸糖果和Xenopus laevis卵分析了收缩环形成的机理。似乎裂变酵母细胞中的收缩环是由核分裂过程中积累在细胞内部区域的F-肌动蛋白电缆形成的。首先，由F-肌动蛋白电缆组成的星状结构是在纺锤体体附近的预言中形成的，然后引导电缆的伸长和环绕细胞。在该区域堆积的F-肌动蛋白电缆与该领先的电缆融合在一起，以使收缩环得到估算。 CDC12在领先电缆的伸长率中起作用，而CDC15在F-肌动蛋白电缆与领先电缆的融合中起作用。小的G蛋白Rho被认为是裂解信号通路的重要组成部分。我们分析了Rho蛋白在裂变酵母中的功能，并发现了一种新型的G蛋白Rho3。 Rho3位于细胞膜。发现新型的formin家族蛋白for3存在于Rho3或Cdc42的下游。 RHO3和FOR3控制肌动蛋白细胞骨架和微管，从而调节细胞的形状和细胞因子的位置。微管在Xenopus卵中的收缩环形成时的形成。微管毒物对微管的破坏不会干扰收缩环的收缩，而是干扰其形成。我们还发现，从两个杆子散发出的微管在裂解沟下彼此连接。我们测试了CA离子通过分析裂解沟周围的CA释放在裂解信号传导中发挥作用的可能性。在裂解沟的前缘都没有发现Ca波和小Ca释放，例如Ca泡芙或Ca Blip。