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.

在第一个减数分裂分裂期间，通过chiasmata连接到相对纺锤形杆（双向方向）的微管连接的同源染色体，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性，并且是流产，不育症和先天缺陷的主要原因。我们的长期目标是了解促进准确的染色体分离的机制，以及使其容易受到染色体分离误差的卵母细胞纺锤体的特征。我们先前使用果蝇的研究，他的雌性雌性导致了一种模型，在该模型中，将两种类型的微管附着用于双向定向。动力学与微管的侧面相互作用的侧向附着建立双向方向。然后，末端附件，动力学附着在微管末端，维持和隔离双向双向同源物。果蝇卵母细胞的一个突出特征是中期I中心主轴，它充当“骨干”，在没有中央事物的情况下将微管组织成双极结构。我们的工作表明，中央主轴在促数期间的双向方向中具有重要作用。在秀丽隐杆线虫和小鼠卵母细胞中的研究表明，中期纺锤可能是摄取体质减数分裂过程中同源染色体双向定向所需的保守元素。在上一个资金期间，我们开发了几种工具来研究卵母细胞双向定向的机制。这些工具包括抗RNAi的翻译，以使关键蛋白质的种系特异性突变体。此外，我们还具有翻译或抗体的试剂，以检测许多调节染色体分离的重要蛋白质，包括Centromere，Kinetochore，Chinetochore，Checkpoint，Checkpoint，Checkpoint和Spindle蛋白质。使用这些工具，我们将研究中央主轴与动力学相互作用以促进双向取向的机制。最终附件的过早稳定可能导致双向缺陷。因此，我们将研究横向附着和双向方向的机制，以及如何调节向末端附件的过渡。这些研究将重点放在两种动力学蛋白CENP-C和SPC105R上，这些蛋白需要加载其他几种动力学和检查点蛋白。我们还将研究中央主轴如何与动力学相互作用并促进准确的双向方向。这些研究将包括建模果蝇，中央主轴突变的实验，这些突变降低了女性的生育能力。该提案的目的是通过一个目标，即了解对卵母细胞很重要的染色体隔离机制。在完成这项工作时，我们将获得有关动力学如何调节从侧面和末端微管附件的过渡的见解。