Chromosome Movement in Prometaphase

描述(申请者摘要)：本项目的目标是了解 有丝分裂染色体如何移动，它们在中期如何排列，以及微管如何 染色体着丝点的附着和物理张力控制着 染色体分离的时机。染色体调控中的缺陷 运动和分离导致染色体不稳定，获得或丢失 细胞分裂过程中的染色体。染色体不稳定性在人骨肉瘤形成中的作用 人类配子会导致先天缺陷，如唐氏综合症。染色体 体细胞分裂的不稳定是一个重要的原因 癌症恶变的因素。矛盾的是，染色体的不稳定性也可能 对癌症化疗中使用的某些药物的有效性至关重要。 细胞分裂的重要步骤是由细胞的结合来调节的 蛋白质泛素到其他蛋白质。许多参与其中的组成酶 泛素的偶联作用已被确定，但其分子途径 它们在细胞周期中受到时间上的调节，或者在细胞内受到空间调节 细胞的不同部分是未知的。这个项目的目的是 确定这些系统的新调节蛋白，并确定时间 并且泛素结合机制的空间控制发生在 细胞分裂。这些研究结合了分子、生化和 先进的显微技术跟踪生化变化和蛋白质 泛素结合机制的相互作用在 哺乳动物细胞有丝分裂的调控。几种药物的体外模型系统 使用细胞提取物、洗涤剂裂解的细胞或合成成分的类型有 也用过。这些模型系统部分地再现了活人体内的事件 细胞，但提供了更好的机会来控制和操纵 分子环境。一组目标寻求绘制步骤，通过这些步骤 染色体运动本身是由泛素结合控制的 有丝分裂早期中期的机械作用。另一组指向 了解细胞周期检查点通路的调节 有丝分裂在控制泛素结合预防早产中的作用 染色体分离和染色体不稳定性。

DESCRIPTION (APPLICANT'S ABSTRACT): The goals of this project are to understand how mitotic chromosomes move, how they align at metaphase, and how microtubule attachment and physical tension at the kinetochores of chromosomes controls the timing of chromosome segregation. Defects in the regulation of chromosome movement and segregation lead to chromosome instability, the gain or loss of chromosomes during cell division. Chromosome instability in the formation of human gametes leads to birth defects such as Down's syndrome. Chromosome instability in the division of somatic cells is an important contributing factor to malignancy in cancer. Paradoxically, chromosome instability may also be critical for the effectiveness of certain drugs used in cancer chemotherapy. Important steps of cell division are regulated by the conjugation of the protein ubiquitin to other proteins. Many of the component enzymes involved in ubiquitin conjugation have been identified but the molecular pathways by which they are temporally regulated in the cell cycle or spatially regulated within different parts of the cell are unknown. The aims of this project are to identify new regulator proteins of these systems and to determine how temporal and spatial control of the ubiquitin conjugation machinery takes place within cell division. These studies use a combination of molecular, biochemical, and advanced microscopic techniques to track the biochemical changes and protein interactions of the ubiquitin conjugation machinery that are important in the regulation of mitosis in mammalian cells. In vitro model systems of several types using cell extracts, detergent-lysed cells or synthesized components are also used. These model systems partially reproduce events within the living cells but provide for better opportunities to control and manipulate the molecular environment. One set of objectives seeks to map the steps by which chromosome movements themselves are controlled by the ubiquitin conjugation machinery during prometaphase in early mitosis. Another set is pointed toward understanding the regulation of the cell cycle checkpoint pathway that functions in mitosis in controlling ubiquitin conjugation to prevent premature chromosome segregation and chromosome instability.