Mechanisms of chromosome motility during mammalian meiosis

哺乳动物减数分裂过程中染色体运动的机制

• 批准号: 10672204
• 负责人: Jayakrishnan Nandakumar
• 金额: $ 47.97万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2027-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10672204
• 关键词: Adopted; Applications Grants; Architecture; Back; Binding; Biochemical; Biological Models; Biology; Cell Nucleus; Cell division; Cells; Chromosome Segregation; Chromosomes; Complement; Complex; Congenital Abnormality; Congenital Disorders; Cytoskeletal Proteins; Cytoskeleton; Cytosol; DNA; Data; Diagnosis; Dissection; Dynein ATPase; Electrons; Ensure; Event; Fertility; Fertility Disorders; Genes; Genetic Crossing Over; Genetic Recombination; Genetic Variation; Germ Cells; Haploidy; Higher Order Chromatin Structure; Homologous Gene; Human; In Vitro; Infertility; Investigation; Joints; Knowledge; Light; Link; Mammals; Meiosis; Meiotic Prophase I; Membrane; Membrane Proteins; Microscopy; Microtubules; Molecular; Motion; Mus; Mutation; Nuclear; Nuclear Envelope; Nuclear Outer Membrane; Organ; Ovum; Positioning Attribute; Preparation; Process; Production; Protein Biochemistry; Proteins; Qualifying; Reproduction; Reproductive Biology; Risk Factors; Sexual Reproduction; Side; Specificity; Spermatocytes; Spontaneous abortion; Structure; Testis; Total Internal Reflection Fluorescent; biophysical techniques; cell motility; cell type; daughter cell; improved; in vitro Assay; in vivo; infertility treatment; insight; interdisciplinary approach; live cell microscopy; molecular modeling; prevent; protein protein interaction; protein reconstitution; reconstitution; recruit; segregation; single molecule; sperm cell; telomere; transmission process

Mechanisms of chromosome motility during mammalian meiosis Project Summary/Abstract Meiosis is a specialized form of cell division of the germline that produces haploid gametes essential for sexual reproduction. A critical step in meiosis is the recombination between homologous chromosomes, also called meiotic crossover, required for the proper segregation of chromosomes into the daughter cells. Imperfect segregation prevents progression through meiosis and is a risk factor for infertility and miscarriage. A detailed understanding of meiotic crossover will enhance the knowledge of meiosis and hold implications for human reproductive biology. Essential to meiotic crossover is a remodeling process in the cell that involves connecting chromosomes in the nucleus to dynein in the cytosol via protein-protein interactions spanning the nuclear envelope. This event allows dynein to move all chromosomes along the nuclear envelope to facilitate the search and pairing of homologous chromosomes for undergoing crossover. A key player in this process is the SUN1-KASH5 LINC complex that spans the nuclear envelope to link chromosomes to dynein. Despite the importance of chromosome-nuclear envelope tethering and motility in mammalian meiosis, a molecular mechanism for this phenomenon is still lacking. Understanding how SUN1-KASH5 performs its meiosis- specific function will generate new knowledge to improve the diagnosis and treatment of fertility disorders. Using a multi-disciplinary approach that includes biochemical/biophysical methods, fixed and live-cell microscopy, single-molecule TIRF microscopy, membrane protein reconstitution, and a specialized mouse meiosis model system, this proposal aims to understand how dynein moves chromosomes to facilitate homolog pairing during meiosis. Aim 1 of the proposal will determine the structural basis, the dynamics, and the meiosis-specificity of the KASH5-dynein interaction instrumental to crossover. Interrogation in mouse spermatocytes will complement the in vitro studies to reveal how the KASH5-dynein interaction helps uphold mouse fertility. Aim 2 of this proposal will determine the higher-order structures adopted by SUN1-KASH5 at the nuclear envelope and how they enable cytosolic dynein forces to move entire chromosomes in the nucleus. This Aim and the grant proposal culminate in the dissection of the molecular mechanism underlying infertility in humans caused by a mutation in the gene encoding KASH5. The proposed studies will reveal how dynein and LINC complexes come together to facilitate the essential process of crossover during mammalian meiosis.

哺乳动物减数分裂过程中染色体运动的机制 项目概要/摘要 减数分裂是种系细胞分裂的一种特殊形式，产生性行为所必需的单倍体配子 生殖。减数分裂的关键步骤是同源染色体之间的重组，也称为 减数分裂交叉，是染色体正确分离到子细胞中所必需的。不完善 分离可防止减数分裂进展，是不孕和流产的危险因素。详细的 对减数分裂交叉的理解将增强减数分裂的知识并对人类产生影响 生殖生物学。减数分裂交叉的关键是细胞中的重塑过程，其中涉及连接 通过跨核的蛋白质-蛋白质相互作用，细胞核中的染色体与细胞质中的动力蛋白 信封。该事件允许动力蛋白沿着核膜移动所有染色体，以促进 搜索和配对同源染色体以进行交叉。这个过程中的一个关键角色是 SUN1-KASH5 LINC 复合物跨越核膜，将染色体与动力蛋白连接起来。尽管 染色体-核膜束缚和运动在哺乳动物减数分裂（一种分子减数分裂）中的重要性 对于这种现象目前还缺乏机制。了解 SUN1-KASH5 如何进行减数分裂 - 特定功能将产生新知识，以改善生育障碍的诊断和治疗。 采用多学科方法，包括生物化学/生物物理方法、固定细胞和活细胞方法 显微镜、单分子 TIRF 显微镜、膜蛋白重建和专门的小鼠 减数分裂模型系统，该提案旨在了解动力蛋白如何移动染色体以促进 减数分裂期间的同源配对。该提案的目标 1 将确定结构基础、动态和 KASH5-动力蛋白相互作用的减数分裂特异性有助于交叉。小鼠审讯 精母细胞将补充体外研究，以揭示 KASH5-动力蛋白相互作用如何帮助维持 小鼠的生育能力。该提案的目标 2 将确定 SUN1-KASH5 在 核膜以及它们如何使胞质动力蛋白力移动细胞核中的整个染色体。 这一目标和拨款提案最终剖析了不孕不育的分子机制 人类由编码 KASH5 的基因突变引起。拟议的研究将揭示动力蛋白和 LINC 复合体聚集在一起，促进哺乳动物减数分裂过程中重要的交换过程。