Mechanisms of Mitotic Spindle Assembly

有丝分裂纺锤体组装机制

• 批准号: 8531289
• 负责人: Lesley Nicole Weaver
• 金额: $ 2.6万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8531289
• 关键词: Biological Models; Cell Cycle; Cells; Centrosome; Chromatin; Chromosomes; Complex; Comprehension; DNA; Development; Disease; Ensure; Fluorescence Resonance Energy Transfer; Genetic Materials; Genome; Genomic Instability; Goals; Growth; Image; Kinetochores; Lead; Mediating; Microscopy; Microtubule-Associated Proteins; Microtubules; Mitosis; Mitotic spindle; Modeling; Molecular Motors; Molecular Structure; Morphogenesis; Morphology; Motor; Normal Cell; Organism; Process; Proteins; Relative (related person); Reproduction; Resolution; Shapes; Somatic Cell; Source; Speed; System; Techniques; Testing; Therapeutic; Therapeutic Agents; Xenopus; base; daughter cell; egg; novel therapeutics; research study; segregation; sensor

DESCRIPTION (provided by applicant): Organism reproduction, development, and survival are dependent on the equal and accurate segregation of genetic material into two daughter cells. The cell ensures the fate of DNA by properly assembling a macromolecular structure called the mitotic spindle to align and segregate chromosomes. The spindle is composed of microtubules (MTs) and many associated proteins that regulate MT dynamics to organize and shape the spindle. There are many proposed models for how the spindle assembles, however, the contributions of centrosomes, kinetochores, and chromatin to this process are not clearly defined. Although centrosomes are a primary source of MT nucleation in somatic cells, chromatin-mediated MT nucleation also occurs. Chromatin-mediated spindle assembly is mediated by the RanGTP and Chromosome Passenger Complex (CPC) gradients in which downstream proteins of these gradients regulate MT dynamics and are important for spindle organization. Many cell cycle related therapeutic techniques are used to alter MT dynamics or motor proteins that are involved in spindle assembly. Therefore, understanding how the spindle is initially organized will be beneficial in characterizing the activity of MT associated proteins that are the targets of therapeutic agents. In this present proposal I will: 1) Determine how the spindle is organized in the absence of chromatin and kinetochores in which I will determine how MTs are nucleated and organized in spindles formed in the absence of these components in two model systems. 2) Define the mechanisms utilized by the RanGTP and CPC gradients for spindle assembly to test the hypothesis that in a normal cell these two gradients overlap and cooperate for proper spindle formation. I will test this model using a FRET-based sensor of the CPC to detect the distribution of the gradient when the RanGTP gradient has been suppressed. Together these experiments will allow for further understanding of how these MT nucleating factors coordinate for proper spindle organization.

描述（由申请方提供）：生物体的繁殖、发育和存活取决于遗传物质平等和准确地分离到两个子细胞中。细胞通过正确组装一种称为有丝分裂纺锤体的大分子结构来排列和分离染色体，从而确保DNA的命运。纺锤体是由微管（MT）和许多相关的蛋白质，调节MT动力学组织和形状的纺锤体。关于纺锤体如何组装有许多模型，然而，中心体、动粒和染色质对这一过程的贡献还没有明确的定义。虽然中心体是体细胞中MT成核的主要来源，但也发生了染色质介导的MT成核。染色质介导的纺锤体组装由RanGTP和染色体乘客复合物（CPC）梯度介导，其中这些梯度的下游蛋白调节MT动力学并且对纺锤体组织是重要的。许多细胞周期相关的治疗技术用于改变MT动力学或参与纺锤体组装的马达蛋白。因此，了解纺锤体最初是如何组织的将有利于表征作为治疗剂靶点的MT相关蛋白的活性。在本提案中，我将：1）确定纺锤体是如何组织在染色质和动粒的情况下，其中我将确定如何在两个模型系统中的MT是有核的，并在纺锤体中组织在这些组件的情况下形成。2)定义RanGTP和CPC梯度用于纺锤体组装的机制，以检验在正常细胞中这两种梯度重叠并合作以形成正确的纺锤体的假设。我将使用CPC的基于FRET的传感器来测试该模型，以检测RanGTP梯度被抑制时的梯度分布。总之，这些实验将允许进一步了解这些MT成核因子如何协调适当的纺锤体组织。