Molecular control of centromere specification and kinetochore assembly

着丝粒规格和着丝粒组装的分子控制

• 批准号: 8964182
• 负责人: Iain McPherson Cheeseman
• 金额: $ 38.03万
• 依托单位: WHITEHEAD INSTITUTE FOR BIOMEDICAL RES
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8964182
• 关键词: Aneuploidy; Binding; Binding Proteins; Cell Cycle; Cell division; Cells; Centromere; Chromatin; Chromosome Segregation; Chromosomes; Complement; Complex; Congenital Abnormality; DNA; DNA Binding; Defect; Deposition; Development; Diagnosis; Disease; Epigenetic Process; Event; Failure; Genes; Genetic Materials; Goals; Histone Fold; Histone H3; Human; Kinetochores; Link; Mediating; Microtubules; Mitosis; Molecular; Molecular Structure; Nature; Nucleosomes; Play; Process; Property; Proteins; Recruitment Activity; Role; Site; Specific qualifier value; Step Tests; Structure; Testing; Time; Variant; Vertebrates; Work; base; cancer therapy; centromere protein A; chromatin modification; daughter cell; genetic information; genome integrity; neoplastic cell; protein structure; public health relevance; research study; segregation; tumor progression; tumorigenesis

 DESCRIPTION (provided by applicant): The goal of this proposal is to define the nature of the kinetochore-DNA interface and determine how centromere-specific chromatin directs the assembly of a functional kinetochore structure in human cells. During each cell division, the entire complement of genetic material must be accurately partitioned to the daughter cells. Even a single chromosome mis-segregation event can be catastrophic, resulting in the loss or gain of hundreds of genes, with severe consequences for development and disease, including tumorigenesis. The central player in directing chromosome segregation is the kinetochore, a large macromolecular structure that mediates attachments between spindle microtubules and a region of each chromosome termed the centromere. Determining the molecular basis for kinetochore function is crucial to understand the defective processes that can give rise to tumor cells, and to evaluate the best targets for the diagnosis and treatment of disease. In vertebrates, centromeres are specified by sequence-independent epigenetic mechanisms that involve the targeted deposition of nucleosomes containing the histone H3-variant, CENP-A. A fundamental unanswered question is how the remainder of the kinetochore is assembled downstream of CENP-A. Our previous work demonstrated that CENP-A is not sufficient to direct assembly of a complete, functional kinetochore structure in human cells. We have identified a heterotetrameric complex comprised of the histone fold proteins CENP-T, -W, -S, and -X as a critical additional component of the kinetochore-DNA interface. The CENP-T-W-S-X complex displays structural similarity to a nucleosome and possesses sequence-independent DNA binding activity. In addition, CENP-T interacts directly with outer kinetochore microtubule-binding proteins to direct kinetochore assembly. Thus, the CENP-T-W-S-X complex plays a pivotal role in connecting the DNA and microtubule interfaces at kinetochores. However, it remains unknown how the CENP-T-W-S-X complex is targeted exclusively to centromeres to generate a single, functional microtubule attachment site on each chromosome. This proposed work will define the mechanisms that direct the centromere localization of the CENP-T-W-S-X complex by assessing: 1) The intrinsic sequence features of the CENP-T-W-S-X complex that are required for its localization, 2) The extrinsic factors that associate with the CENP-T-W-S-X complex to deposit or maintain it at centromeres, and 3) The regulatory modifications and chromatin features that control CENP-T-W-S-X complex localization.

 描述（由适用提供）：该建议的目的是定义动力学DNA界面的性质，并确定中心粒特异性染色质如何指导人类细胞中功能性动力学结构的组装。在每个细胞分裂期间，必须将整个遗传物质的整个完成都准确地分配给子细胞。即使是单一的染色体错误隔离事件也可能是灾难性的，导致数百个基因的损失或增益，对发育和疾病（包括肿瘤发生）造成严重后果。指导染色体分离的核心参与者是动元，这是一种大型大分子结构，可介导纺锤微管之间的附着和每个染色体的区域，称为中心粒。确定动力学功能的分子基础对于了解可能导致肿瘤细胞的缺陷过程以及评估诊断和治疗疾病的最佳靶标至关重要。在脊椎动物中， 中心粒由序列无关的表观遗传机制指定，涉及含有组蛋白H3变量CENP-A的核商品的靶向沉积。一个基本的未解决的问题是，剩余的动元如何在CENP-A下游组装。我们以前的工作表明，CENP-A不足以指导人类细胞中完整的功能性动力学结构。我们已经将组蛋白折叠蛋白CENP -T，-W，-S和-X的杂型化合物络合物确定为kinetochore -DNA接口的关键附加组件。 CENP-W-W-S-X复合物显示出与核体的结构相似性，并具有与序列无关的DNA结合活性。此外，CENP-T直接与外部动力学微管结合蛋白直接相互作用，以直接直接动力学组装。这就是CENP-W-S-X复合物在连接动力学上的DNA和微管接口方面起关键作用。然而，尚不清楚CENP-W-S-X复合物如何仅针对centromeres来生成每个染色体上的单个功能性微管附着位点。这项提出的工作将定义指导CENP-T-W-S-X复合物中心粒的机制：1）CENP-T-W-S-X复合物的固有序列特征，其定位所需的固有序列特征，2）与CENP-T-W-S-X-X-X-X-X-X-S-X复合物相关的外部因素，以使其与CENP-T-W-S-S-X相关联，以使其沉积或在Centrys and Contrivic and Chort and Chort and Chort and Chort and Chort and Chort and Chort and Chort and Chort and Chort and Chort and Chort and 3）and 3）and 3）。 CENP-W-W-SX复合物定位。