Multifunctional molecular switch essential for cell morphogenesis

细胞形态发生必需的多功能分子开关

基本信息

批准号：
14380325
负责人：
OHYA Yoshikazu
金额：
$ 9.54万
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：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

The coordination of cell cycle events during cell proliferation is attained, in part, through surveillance systems. In the budding yeast Saccharomyces cerevisiae, cell cycle progression is restrictively regulated and some events during cell cycle are regulated by the checkpoints monitoring DNA damage, DNA replication, integrity of the spindle, spindle positioning and cell morphogenesis. It still remained unclear whether all of the checkpoint controls have been identified.Here we found that a novel checkpoint exists to couple cell wall remodeling with spindle formation. fks1 mutants defective in 1,3-β-glucan synthase activity failed to form a mature bud. Surprisingly, these cells arrested with post-replicative DNA but quite low level of Clb2p, and without forming bipolar spindles. We found that wac1 (wall-checkpoint defective) mutation that abolished this arrest caused the accumulation of Clb2p and CLB2 mRNA and leaded to formation of bipolar spindles despite glucan-synthesis perturbation. These results indicate the existence of a novel checkpoint mechanism to coordinate entry into mitosis, and suggest that Wac1p is required to achieve this checkpoint function through a transcriptional regulation of CLB2. Furthermore, we revealed that WAC1 was identical with ARP1 (actin-related protein). Arp1p, Nip100p and Jnm1p, which are components of the dynactin complex, are required to achieve the G2 arrest while keeping cells highly viable. These results indicate that the dynactin complex have a regulatory role in the novel checkpoint to monitor cell wall synthesis.

细胞增殖过程中细胞周期事件的配位是通过监视系统的部分实现的。在酿酒酵母的萌芽酵母菌中，细胞周期的进展受到限制调节，并且在细胞周期期间的某些事件受到检查点监测DNA损伤，DNA复制，纺锤体定位的完整性，纺锤体定位和细胞形态发生的调节。仍然不清楚是否已经确定了所有检查点控件。在这里，我们发现存在一个新颖的检查点，可将细胞壁重塑与纺锤体形成。 1,3-β-葡聚糖合酶活性中有缺陷的FKS1突变体未能形成成熟的芽。令人惊讶的是，这些细胞用复制后DNA捕获，但CLB2P水平相当低，并且没有形成双极纺锤体。我们发现废除这种停滞的WAC1（壁检查缺陷）突变导致CLB2P和CLB2 mRNA的积累，尽管葡萄糖 - 合成扰动，但仍导致双极纺锤体形成。这些结果表明存在一种新型检查点机制来协调有丝分裂的进入，并建议通过CLB2的转录调控来实现此检查点函数。此外，我们揭示了WAC1与ARP1（与肌动蛋白相关的蛋白质）相同。 ARP1P，NIP100P和JNM1P是Dynactin络合物的组成部分，在保持细胞高度生存的同时需要实现G2停滞。这些结果表明，在新的检查点中，dynactin复合物具有监测细胞壁合成的调节作用。