Protection of Centromeric Cohesion by Bub1 and Sgo1

Bub1 和 Sgo1 对着丝粒凝聚力的保护

基本信息

批准号：
7884116
负责人：
HONGTAO YU
金额：
$ 30.92万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-08-10 至 2012-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7884116
关键词：
45-kDa nuclear factor of activated T-cells Address Adopted Affinity Aneuploidy Area Binding Binding Proteins Biochemical Biological Assay C-terminal Cells Centromere Chromosomal Instability Chromosome Arm Chromosome Cohesion Chromosome Segregation Chromosomes Cleaved cell Complex Congenital Abnormality Double-Stranded RNA Down Syndrome Electrophoretic Mobility Shift Assay Evolution Excision Fission Yeast Genetic Genetic Materials Goals Hand Hela Cells Heterochromatin Human In Vitro Kinetochores Lead Ligands Ligase Light Maintenance Malignant Neoplasms Mammalian Cell Mediating Meiosis Metaphase Methods Mitosis Mitotic Mitotic spindle Molecular Mutation Nucleic Acid Binding Organism Phenotype Phosphoric Monoester Hydrolases Phosphorylation Phosphorylation Site Phosphotransferases Play Polynucleotide Adenylyltransferase Precipitation Prevention Process Prophase Protein Dephosphorylation Protein Family Protein phosphatase Proteins RNA RNA Binding RNA Interference RNA Interference Pathway RNA-Binding Proteins Recombinants Recruitment Activity Research Research Personnel Residual state Role Sister Chromatid Structure Testing Transferase Ubiquitination Yeasts cohesin cohesion crosslink daughter cell heterochromatin-specific nonhistone chromosomal protein HP-1 human PLK1 protein in vivo insight interest man mutant novel oligoadenylate premature programs protein complex reconstitution research study separase tumorigenesis

项目摘要

DESCRIPTION (provided by applicant): The genetic stability of an organism depends on the accurate partition of sister chromatids into two daughter cells during mitosis, which in turn requires the maintenance of the physical linkage (cohesion) between sister chromatids until their bipolar attachment to the mitotic spindle. Removal of cohesin (the protein complex that maintains sister chromatid cohesion) from chromosomes then leads to sister chromatid separation. In vertebrate cells, removal of cohesin occurs in two steps. At prophase, most of cohesin along the chromosome arms is removed through Polo-like kinase (Plk1)/Aurora B-dependent phosphorylation of cohesin. At metaphase, the residual centromeric pool of cohesin is cleaved by separase to allow sister chromatid separation. The long-term goal of my lab is to understand the molecular mechanism of chromosome segregation in mammalian cells. In this proposal, we will address an interesting puzzle in this area: how is the centromeric cohesin shielded from the actions of Plk1 /Aurora B in prophase? We have recently provided evidence to suggest that the spindle checkpoint kinase Bub1 targets and the Sgo1 centromeric protein and protein phosphatase 2A (PP2A) to centromeres where they counteract the phosphorylation of cohesin by Plk1 and other mitotic kinases. In Specific Aims 1 and 2, we will further delineate the mechanisms by which Bub1, Sgo1, and PP2A collaborate to protect centromeric cohesion. On the other hand, our results also point to a PP2A-independent role of Sgo1. Indeed, we have made two novel and related findings in the past year. Sgo1 directly interacts with an RNA-binding protein complex called ILF2-ILF3 (interleukin enhancer binding factors 2 and 3). Sgo1 itself binds to RNA in vitro. Experiments are planned in Aims 3 and 4 to establish the in vivo relevance of these findings. Premature loss of centromeric sister chromatid cohesion leads to chromosome missegregation and abnormal numbers of chromosomes in daughter cells (aneuploidy), which contributes to cancer formation and birth defects. The proposed research will shed light on the mechanism of chromosome segregation and may in turn lead to better understanding and prevention of chromosomal instability and aneuploidy in human cancers and birth defects, such as Down Syndrome.

描述（由申请人提供）：生物体的遗传稳定性取决于有丝分裂过程中姐妹染色单体准确划分为两个子细胞，这反过来又需要维持姐妹染色单体之间的物理连接（内聚力），直到它们双极附着到子细胞上。有丝分裂纺锤体。从染色体上去除粘连蛋白（维持姐妹染色单体凝聚力的蛋白质复合物）会导致姐妹染色单体分离。在脊椎动物细胞中，粘连蛋白的去除分两个步骤进行。在前期，沿染色体臂的大部分粘连蛋白通过 Polo 样激酶 (Plk1)/Aurora B 依赖性粘连蛋白磷酸化被去除。在中期，残留的粘连蛋白着丝粒库被分离酶切割，以允许姐妹染色单体分离。我实验室的长期目标是了解哺乳动物细胞染色体分离的分子机制。在本提案中，我们将解决该领域的一个有趣的难题：着丝粒粘连蛋白如何在前期免受 Plk1 /Aurora B 的作用？我们最近提供的证据表明，纺锤体检查点激酶 Bub1 和 Sgo1 着丝粒蛋白和蛋白磷酸酶 2A (PP2A) 靶向着丝粒，在着丝粒中它们抵消 Plk1 和其他有丝分裂激酶对粘连蛋白的磷酸化。在具体目标 1 和 2 中，我们将进一步描述 Bub1、Sgo1 和 PP2A 协作保护着丝粒凝聚的机制。另一方面，我们的结果也表明 Sgo1 具有独立于 PP2A 的作用。事实上，我们在过去的一年中取得了两项新颖且相关的发现。 Sgo1 直接与称为 ILF2-ILF3（白介素增强子结合因子 2 和 3）的 RNA 结合蛋白复合物相互作用。 Sgo1 本身在体外与 RNA 结合。目标 3 和 4 计划进行实验以确定这些发现的体内相关性。着丝粒姐妹染色单体内聚力的过早丧失会导致子细胞中染色体错误分离和染色体数量异常（非整倍体），从而导致癌症形成和出生缺陷。拟议的研究将揭示染色体分离的机制，并可能反过来更好地理解和预防人类癌症和出生缺陷（如唐氏综合症）中的染色体不稳定性和非整倍性。