Microtubule Motor-Mechanisms of Chromosome Movements

染色体运动的微管运动机制

• 批准号: 6505418
• 负责人: DAVID James SHARP
• 金额: $ 26.63万
• 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/6505418
• 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）：成功有丝分裂需要从母亲到子细胞的基因组相等的分离。这发生在有丝分裂主轴上，这是一种使用微管（MTS）和基于MT的运动蛋白与细胞分裂协调染色体运动的细胞内机器。我们提出的研究的目的是阐明将染色体定位在主轴上的运动机制。我们的中心假设是，这涉及多个电动机同时发挥作用的合作活性，以产生互补和拮抗作用的动态平衡。具体而言，位于动力学上的电动机会产生针对纺锤形杆的力，而位于染色体臂上的电动机会产生针对中期板的力。我们认为，当这些“极向”和“板的力”力精确平衡时，稳态结构形成和染色体保持稳定的位置，如中期一样。通过向上的一部分电动机的上调或下调这种平衡，导致特定的染色体运动，例如在后期A期间进行染色单体到极的运动。为了研究此过程，我们将使用果蝇早期胚胎作为我们的主要实验系统进行以下特定目标：目标1）表征具有高度散布和时间质量的染色体的速率和结构基础。目标2）检验了动力学结合电动机，动力蛋白/dynactin和kini驱动素的假设，可以协同作用以在染色体上产生极力。目标3）检验以下假设：染色体臂结合电动机KLP38B和点头合作，可以在染色体上产生板岩力。目标4）检查极向电动机和板向电动机之间存在的功能间相互关系，以确定染色体是否受到反平衡运动生成力的影响。我们的整体实验策略是利用单个电动机的分析结果来制定和检验有关这些电动机如何共同工作以驱动在细胞增殖过程中必须发生的基因组的相干和紧密控制的重新组织的更广泛的假设。由于此过程中的缺陷导致许多人类疾病，包括先天缺陷和癌症，因此我们的发现应提供对这些疾病原因的见解，并提出潜在的治疗方法来治疗其治疗方法。