How are kinetochores remodelled for chromosome segregation during meiosis?

着丝粒将染色体附着在微管上，以调节有丝分裂和减数分裂期间染色体的分离。在减数分裂形成配子的过程中，着丝粒被调整，同源染色体在减数分裂I中分离，姐妹染色单体在减数分裂II中分离。为了实现这一点，动粒在同源配对、减数分裂重组的调节和减数分裂I期间的姐妹动粒共定向中发挥专门的作用。这些减数分裂的特定性质的着丝粒收购耦合到专门的着丝粒组装和拆卸途径。1-3.这个项目的目的是了解着丝粒是如何在减数分裂中重塑，以指导染色体分离成配子。为了揭示减数分裂中动粒重塑的保守机制，两个不相关的酵母物种，酿酒酵母和粟酒裂殖酵母，将用于两个目的：1。确定在减数分裂早期，内部动粒如何指导外部动粒组装。我们发现了一个在减数分裂开始时不可或缺的动粒组装途径，但在有丝分裂中则不然。我们假设，特定的招聘调节因子（激酶，磷酸酶）的内部动粒触发装配或维护外动粒在减数分裂早期。这一想法将使用定向诱变（使用CRISPR-Cas9）、免疫沉淀/质谱、磷酸化蛋白质组学和活细胞显微镜的组合进行测试。了解着丝粒重塑如何允许姐妹着丝粒融合在减数分裂I外着丝粒解体在减数分裂前期和重组在前期出口的假设，以帮助建立姐妹着丝粒共同取向在减数分裂I，孟德尔分离的基础。In S.在酿酒酵母中，姐妹动粒由一种称为单核蛋白的复合物融合，而一种称为Spo 13的蛋白质也是单取向所必需的。In S. pombe的monopolin是单取向的，但Moa 1蛋白，Spo 13的功能同源物是必需的。比较生物化学和细胞生物学测定将被用来确定之间的关系monopolin和Spo 13/Moa 1为基础的共取向机制。

Kinetochores attach chromosomes to microtubules to mediate their segregation during mitosis and meiosis. During gamete formation by meiosis, kinetochores are adapted so that homologous chromosomes segregate in meiosis I and sister chromatids segregate in meiosis II. To achieve this, kinetochores take on specialized roles in homolog pairing, regulation of meiotic recombination and sister kinetochore co-orientation during meiosis I. Acquisition of these meiosis-specific properties of kinetochores is coupled to specialized kinetochore assembly and disassembly pathways. 1-3. The aim of this project is to understand how kinetochores are remodelled in meiosis to direct the segregation of chromosomes into gametes. To uncover conserved mechanisms of kinetochore remodelling in meiosis, two unrelated yeast species, Saccharomyces cerevisiae and Schizosaccharomyces pombe, will be used in two aims:1. Determine how the inner kinetochore directs outer kinetochore assembly in early meiosis.We discovered a kinetochore assembly pathway that is indispensable at the onset of meiosis, but not in mitosis. We hypothesise that specific recruitment of regulator factors (kinases, phosphatases) to the inner kinetochore triggers assembly or maintenance of the outer kinetochore in early meiosis. This idea will be tested using a combination of directed mutagenesis (using CRISPR-Cas9), immunoprecipitation/mass spectrometry, phosphoproteomics and live-cell microscopy.2. Understand how kinetochore remodelling allows sister kinetochore fusion in meiosis IThe outer kinetochore disassembly at meiotic prophase and reassembly at prophase exit is hypothesised to help establish sister kinetochore co-orientation during meiosis I, the basis of Mendelian segregation. In S. cerevisiae, sister kinetochores are fused by a complex called monopolin and a protein known as Spo13 is also required for monoorientation. In S. pombe, monopolin is dispensable for monoorientation but the Moa1 protein, a functional homolog of Spo13 is required. Comparative biochemical and cell biological assays will be used to determine the relationship between monopolin and Spo13/Moa1-based co-orientation mechanisms.