Microtubule Motor-Mechanisms of Chromosome Movements

染色体运动的微管运动机制

• 批准号: 6644128
• 负责人: DAVID James SHARP
• 金额: $ 25.89万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-15 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6644128
• 关键词: Drosophilidae; antibody; cell cycle; cell line; centromere; chromosome movement; confocal scanning microscopy; dynein ATPase; enzyme inhibitors; freeze substitution; green fluorescent proteins; kinesin; laboratory mouse; laboratory rabbit; microtubules; mitotic spindle apparatus; molecular polarity; protein protein interaction; protein structure function; spindle pole body

DESCRIPTION (provided by applicant): Successful mitosis requires the equal segregation of the genome from mother to daughter cells. This occurs on the mitotic spindle, an intracellular machine that uses microtubules (MTs) and MT-based motor proteins to coordinate chromosome movements with cell division. The goal of our proposed studies is to elucidate the motor-mechanisms that position chromosomes on the spindle. Our central hypothesis is that this involves the cooperative activity of multiple motors functioning simultaneously to generate a dynamic balance of complementary and antagonistic forces. Specifically, motors positioned on kinetochores generate forces directed toward the spindle poles while motors positioned on chromosome arms generate forces directed toward the metaphase plate. We posit that when these 'poleward' and 'plateward' forces precisely balance, a steady-state structure forms and chromosomes maintain a stable position, as during metaphase. Tipping this balance, via the up- or down-regulation of a subset of motors, results in specific chromosome movements such as chromatid-to-pole motion during anaphase A. To study this, we will carry out the following specific aims using Drosophila early embryos as our primary experimental system: Aim 1) Characterize the rates and structural basis of chromosome motility with high spatial and temporal resolution. Aim 2) Test the hypothesis that the kinetochore binding motors, dynein/dynactin and KinI kinesins, work cooperatively to generate poleward forces on chromosomes. Aim 3) Test the hypothesis that the chromosome-arm binding motors, KLP38B and Nod, work cooperatively to generate plateward forces on chromosomes. Aim 4) Examine the functional inter-relationships that exist between sets of poleward and plateward motors to determine whether chromosomes are subjected to counterbalancing motor-generated forces. Our overall experimental strategy is to utilize the results of analyses of individual motors to formulate and test broader hypotheses regarding how these motors work collectively to drive the coherent and tightly controlled reorganization of the genome that must occur during cell proliferation. Because defects in this process lead to numerous human maladies, including birth defects and cancer, our findings should provide insights into the causes of these diseases and suggest potential therapeutic approaches to their treatment.

描述（由申请人提供）：成功的有丝分裂需要基因组从母细胞到子细胞的平等分离。这种情况发生在有丝分裂纺锤体上，这是一种细胞内机器，使用微管 (MT) 和基于 MT 的运动蛋白来协调染色体运动与细胞分裂。我们提出的研究的目标是阐明将染色体定位在纺锤体上的运动机制。我们的中心假设是，这涉及同时运行的多个电机的协作活动，以产生互补力和对抗力的动态平衡。具体来说，位于着丝粒上的电机产生指向纺锤体极的力，而位于染色体臂上的电机产生指向中期板的力。我们假设，当这些“极地”和“平板”力精确平衡时，就会形成稳态结构，并且染色体会保持稳定的位置，就像中期一样。通过上调或下调运动子集来打破这种平衡，会导致特定的染色体运动，例如后期 A 期间染色单体到极的运动。为了研究这一点，我们将使用果蝇早期胚胎作为我们的主要实验系统来实现以下具体目标： 目标 1）以高空间和时间分辨率表征染色体运动的速率和结构基础。目标 2) 检验动粒结合马达、动力蛋白/动力蛋白和 KinI 驱动蛋白协同工作以在染色体上产生极向力的假设。目标 3) 检验染色体臂结合马达 KLP38B 和 Nod 协同工作以在染色体上产生平板力的假设。目标 4) 检查极向电机组和向平板电机组之间存在的功能相互关系，以确定染色体是否受到平衡电机产生的力的影响。我们的总体实验策略是利用单个马达的分析结果来制定和测试更广泛的假设，这些假设涉及这些马达如何共同工作以驱动细胞增殖过程中必须发生的连贯且严格控制的基因组重组。由于这一过程中的缺陷会导致许多人类疾病，包括出生缺陷和癌症，因此我们的研究结果应该有助于深入了解这些疾病的原因，并提出潜在的治疗方法。