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: 10693152
• 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/10693152
• 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; Human; Infertility; Insecta; Kinesin; Kinetochores; Klinefelter' s Syndrome; Lateral; Lead; Link; Mammals; Meiosis; Metaphase; Microtubules; Modeling; Mus; Mutation; N-terminal; Oocytes; Organism; Orthologous Gene; Predisposition; 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 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，同源染色体通过交叉连接到来自相反纺锤体两极的微管上（双向），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，并且是流产、不育和出生缺陷的主要原因。我们的长期目标是了解促进染色体精确分离的机制，以及使其易于发生染色体分离错误的卵母细胞纺锤体的特征。我们以前的研究使用果蝇雌性导致了一个模型，其中两种类型的微管附着用于双向。横向附件，其中动粒与微管的侧面相互作用，建立双向定位。然后，端对附件，其中动粒附着到微管的末端，维持和分离双向同源物。果蝇卵母细胞的一个显著特征是中期I的中央纺锤体，它起着“骨架”的作用，在没有中心体的情况下将微管组织成双极结构。我们的工作表明，纺锤体在前中期的双向定位中起着重要作用。在C. elegans和小鼠卵母细胞的研究表明，中期纺锤体可能是无中心体减数分裂过程中同源染色体双向定位所需的保守元件。在上一个资助期，我们开发了几种工具来研究卵母细胞中双向取向的机制。这些工具包括RNAi抗性转基因，以制造关键蛋白质的种系特异性突变体。此外，我们有试剂，无论是转基因或抗体，以检测许多重要的蛋白质，调节染色体分离，包括着丝粒，动粒，检查点和纺锤体蛋白。有了这些工具，我们将调查的机制，中央主轴与动粒相互作用，以促进双向定位。很可能是端对附着体的过早稳定导致双向缺陷。因此，我们将研究横向附件和双向的机制，以及如何过渡到端对附件的调节。这些研究将集中在两个动粒蛋白，CENP-C和SPC 105 R，这是需要加载其他几个动粒和检查点蛋白。我们还将研究中心纺锤体如何与动粒相互作用，并促进准确的双向定位。这些研究将包括在果蝇中建立模型的实验，中心纺锤体突变会降低人类女性的生育能力。本建议的目的是通过一个目标，以了解染色体分离的机制，卵母细胞的重要。在完成这项工作，我们将获得的见解如何着丝粒调节过渡到横向和端对微管的附着。