Mechanisms of spindle formation

描述(申请人提供)：有丝分裂是细胞生命中的一个关键阶段。在这个阶段，两极纺锤体结构被组织起来，将复制的染色体分离到两个子细胞中。主轴的结构和功能要求精密度、坚固性和保真度。与纺锤体相关的缺陷可能会导致染色体分离或非整倍体缺陷，这与某些类型的癌症有关。纺锤体是由微管、微管相关蛋白(MAP)、分子马达和其他调节蛋白组成的大分子机器。人们非常感兴趣的是分子马达，它执行的工作包括将微管连接并滑动以形成双极纺锤体，或解聚微管以保持适当的纺锤体长度，或将染色体携带到相反的纺锤体极。令人惊讶的是，虽然我们对参与有丝分裂的马达了解很多，但我们仍然对MAP和其他调节蛋白以及它们如何与马达协调以实现正确的纺锤体形成知之甚少。我的实验室使用相对简单的分裂酵母、裂殖酵母和人类培养细胞来研究纺锤体组织和功能的保守机制。这个特别的项目集中在最初的两极纺锤体是如何在有丝分裂开始时形成的，这个阶段被称为前期。我们将重点放在有助于纺锤体形成的图谱上。利用裂解酵母作为基因发现工具，我们已经开始定义一种新基因的作用，我们称之为psr1+(极点分离调节因子1)。我们的工作表明，psr1p组织了最初的两极纺锤体 前期工作。Psr1缺失导致高频率的单极纺锤体和随后的染色体分离缺陷。裂解酵母Psr1+似乎与人类功能同源。我们已经开始描述一种新的人类基因，我们称之为PSR1。在HeLa细胞中，PSR1的siRNA还导致高频率的单极纺锤体和随后的染色体分离缺陷。这项建议旨在结合现代细胞和分子生物学技术在分裂酵母和人类培养细胞、生物化学、高分辨率光学活细胞成像和创新的微流体技术来控制细胞微环境，以达成对两极纺锤体形成的机制的理解。

DESCRIPTION (provided by applicant): Mitosis is a key stage during the life of a cell. It is the stage where a bipolar spindle structure is organized to segregate duplicated chromosomes into the two daughter cells. Spindle organization and function require exquisite precision, robustness and fidelity. Defects associated with the spindle can lead to defects in chromosomal segregation, or aneuploidy, which has been correlated with some types of cancer. The spindle is a macromolecular machine made of microtubules, microtubule-associated proteins (MAPs), molecular motors and other regulatory proteins. Of intense interest have been molecular motors, which perform work such as cross-linking and sliding microtubules apart to form the bipolar spindle, or to depolymerize microtubules to maintain proper spindle lengths, or to carry chromosomes to opposite spindle poles. Surprisingly, while we have learned much about motors involved in mitosis, we still know very little about the MAPs and other regulatory proteins and how they coordinate with motors to bring about proper spindle formation. My laboratory uses the relatively simple fission yeast Schizosaccharomyces pombe and human cultured cells to address conserved mechanisms of spindle organization and function. This particular project focuses on how the initial bipolar spindle is formed at the start of mitosis, the stage termed prophase. We focus on the MAPs that contribute to spindle formation. Using fission yeast as a gene discovery tool, we have begun to define the roles of a new gene we called psr1+ (poles separation regulator 1). Our work indicates that psr1p organizes the initial bipolar spindle during prophase. Psr1-deletion leads to high frequency of monopolar spindles and subsequent chromosome segregation defects. Fission yeast psr1+ appears to have a human functional homolog. We have begun to characterize a novel human gene we called PSR1. In HeLa cells, siRNA of PSR1 also leads to high frequency of monopolar spindles and subsequent chromosome segregation defects. This proposal aims to combine modern cell and molecular biology techniques in fission yeast and human cultured cells, biochemistry, high-resolution optical live-cell imaging, and innovative microfluidic techniques to control cellular microenvironment, to reach a mechanistic understanding of bipolar spindle formation.