Homolog bi-orientation and segregation in oocyte acentrosomal meiosis

卵母细胞中心体减数分裂的同源双向和分离

• 批准号: 10473876
• 负责人: KIM S MCKIM
• 金额: $ 40.66万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10473876
• 关键词: Aneuploidy; Antibodies; Binding; Caenorhabditis elegans; Centromere; Centrosome; Chromosome Segregation; Chromosomes; Complex; Congenital Abnormality; Defect; Disease; Down Syndrome; Drosophila genus; Drosophila melanogaster; Elements; Ensure; Female; Female infertility; Fertility; Funding; Goals; Homologous Gene; Infertility; Insecta; Kinesin; Kinetochores; Klinefelter' s Syndrome; Lateral; Lead; Link; Mammals; Meiosis; Metaphase; Microtubules; Modeling; Mus; Mutation; N-terminal; Oocytes; Organism; Orthologous Gene; Process; Prometaphase; Prophase; Proteins; RNA Interference; Reagent; Research; Resistance; Role; Side; Spontaneous abortion; Structure; Testing; Transgenes; Turner' s Syndrome; Variant; Vertebral column; Work; centromere protein A; centromere protein C; chromosome number abnormality; experimental study; human error; human female; human model; insight; interest; mutant; premature; recruit; segregation; tool

During the first meiotic division, homologous chromosomes linked by chiasmata attach to microtubules from opposite spindle poles (bi-orientation) and then segregate. In humans, errors in chromosome segregation in the oocyte lead to aneuploidy and are the leading cause of miscarriage, infertility and birth defects. Our long-term goal is to understand the mechanisms that promote accurate chromosome segregation, and the features of the oocyte spindle that make it susceptible to chromosome segregation errors. Our previous research using Drosophila melanogaster females has led to a model in which two types of microtubule attachment are used for bi-orientation. Lateral attachments, where the kinetochores interact with the sides of microtubules, establish bi-orientation. Then end-on attachments, where the kinetochores attach to the end of microtubules, maintain and segregate bi-orientated homologs. A prominent feature of the Drosophila oocyte is the metaphase I central spindle, which functions as a “backbone”, organizing the microtubules into a bipolar structure in the absence of centrosomes. Our work has shown that the central spindle has an important role in bi-orientation during pro-metaphase. Studies in C. elegans and mouse oocytes indicate that the metaphase central spindle may be a conserved element required for the bi-orientation of homologous chromosomes during acentrosomal meiosis. In the previous funding period, we developed several tools to study the mechanisms of bi- orientation in oocytes. These tools include RNAi resistant transgenes in order to make germline-specific mutants of key proteins. Furthermore, we have the reagents, either transgenes or antibodies, to detect many of the important proteins that regulate chromosome segregation, including centromere, kinetochore, checkpoint and spindle proteins. With these tools, we will investigate the mechanisms by which the central spindle interacts with the kinetochores to promote bi-orientation. It is likely that premature stabilization of end-on attachments leads to bi-orientation defects. Therefore, we will investigate the mechanisms of lateral attachments and bi-orientation, and how the transition to end-on attachments is regulated. These studies will focus on two kinetochore proteins, CENP-C and SPC105R, which are required to load several other kinetochore and checkpoint proteins. We will also investigate how the central spindle interacts with the kinetochores and promotes accurate bi-orientation. These studies will include experiments to model in Drosophila, central spindle mutations that decrease fertility in human females. The Aims of this proposal are linked by a goal to understand the mechanisms of chromosome segregation important to oocytes. In completing this work, we will have gained insights into how kinetochores regulate the transition from lateral and end-on microtubule attachment.

在第一次减数分裂期间，通过交叉连接的同源染色体从相反的纺锤体极（双向）附着到微管上，然后分离。在人类中，卵母细胞中染色体分离的错误导致非整倍体，是流产、不孕和不育的主要原因。我们的长期目标是了解促进准确染色体分离的机制，以及使其容易出现染色体分离错误的卵母细胞纺锤体的特征。使用雌性果蝇建立了一种模型，其中两种类型的微管附着用于双向附着，其中动粒与微管的侧面相互作用，然后建立双向附着，其中动粒。附着在微管末端，维持和分离双向同源物 果蝇卵母细胞的一个显着特征是中期 I 中央。我们的工作表明，在线虫的前中期研究中，中央纺锤体起着“骨架”的作用，将微管组织成双极结构。小鼠卵母细胞表明，中期中央纺锤体可能是无中心体减数分裂过程中同源染色体双向取向所需的保守元件。在之前的资助期间，我们开发了几种。研究卵母细胞双向机制的工具。这些工具包括 RNAi 抗性转基因，以产生关键蛋白质的种系特异性突变体。此外，我们还有试剂（转基因或抗体）来检测许多重要的蛋白质。调节染色体分离，包括着丝粒、着丝粒、检查点和纺锤体蛋白，我们将研究中央纺锤体与着丝粒相互作用以促进双向的机制。端部附着的过早稳定可能会导致双向缺陷，因此，我们将研究横向附着和双向的机制，以及如何调节端部附着的过渡。这些研究将集中于两个动粒。蛋白质、CENP-C 和 SPC105R，它们是加载其他几种着丝粒和检查点蛋白质所必需的。我们还将研究中央纺锤体如何与着丝粒相互作用并促进。这些研究将包括在果蝇中建立模型的实验，该突变会降低人类女性的生育能力。该提案的目标是了解对卵母细胞重要的染色体分离机制。 ，我们将深入了解动粒如何调节横向和末端微管附着的转变。