Meiotic chromosome synapsis and recombination in yeast

描述（由申请人提供）：减数分裂是一种特殊的细胞程序，根据有性生殖的需要，从二倍体亲本细胞产生单倍体雄性和雌性配子。我们的研究解决了这个程序的中心独特的功能，一系列复杂的相互作用之间的母亲和父亲的同源物，在三个领域：（I）独立的配对。这一过程也发生在某些生物体的有丝分裂细胞中（“体细胞配对”），是一种主要的染色体行为，其基本分子机制尚不清楚。我们将应用高通量3C分析，以确定配对的“热点”，并在一个单一的定义的基因座配对检查特定的变量的作用。我们将通过活细胞中GFP标记的位点的运动相关分析来进一步分析配对相互作用。如果时间允许，我们将开始研究分离（然后表征）成对分子的可能性。(II)与事件有关的事件。我们将继续分析在DNA水平上的重组的基本性质的分离和AFM可视化的重组中间体（特别是双霍利迪路口）从一个单一的重组“热点”。我们将开始研究交叉干扰的功能，当过度生产，增加或减少这个过程的鲁棒性搜索;此外，我们将试图区分可能的干扰模型，通过创建，并评估的影响，一个定义的“循环”沿着染色体。最后，我们将继续探索轴组件的重组的作用：研究的“有丝分裂”粘连蛋白Mcd 1/Scc 1/Rad 21;高分辨率分析蛋白质定位的局部变化，通过连接MNase研究;和进一步定义的染色体组织通过高分辨率分析粘连蛋白和凝聚蛋白定位沿着粗线期染色体。(III)运动和力学。我们将改进我们的方法，分离个别粗线期染色体作为对象的机械研究。我们将继续我们最近发现的肌动蛋白和端粒为基础的染色体运动使用现有的试剂和寻找“运动突变体”。减数分裂同源物间相互作用的缺陷是许多类型的遗传性不育以及大多数染色体非整倍性的基础，所有这些都带来了重大的社会负担（例如唐斯综合征）。对这些过程的基本了解对于这些疾病的诊断和潜在改善至关重要。

DESCRIPTION (provided by applicant): Meiosis is the specialized cellular program that produces haploid male and female gametes from a diploid parental cell as required for sexual reproduction. Our research addresses the central unique feature of this program, a complex series of interactions between maternal and paternal homologs, in three areas: (I) Recombination-independent pairing. This process, which also occurs in mitotically-dividing cells of some organisms ("somatic pairing"), is one of the major chromosomal behaviors for which there is no hint of the fundamental molecular mechanism. We will apply high-throughput 3C analysis to identify pairing "hot spots" and to examine the roles of specific variables of interest to pairing at a single defined locus. We will further analyze pairing interactions by motion correlation analysis of GFP-tagged loci in living cells. As time permits, we will begin to investigate the possibility of isolating (and then characterizing) paired molecules. (II) Recombination-related events. We will continue to analyze the basic nature of recombination at the DNA level by isolation and AFM visualization of recombination intermediates (notably double Holliday junctions) from a single recombination "hot spot". We will initiate a study of crossover interference by searching for functions which, when overproduced, increase or decrease the robustness of this process; also, we will try to distinguish among possible models for interference by creating, and assessing the effects of, a defined "loop" along a chromosome. Finally, we will continue to explore the roles of axis components for recombination by: studies of the "mitotic" cohesin Mcd1/Scc1/Rad21; high resolution analysis of local variations in protein localization via linked MNase studies; and further definition of chromosome organization via high resolution analysis of cohesin and condensin localization along pachytene chromosomes. (III) Motion and mechanics. We will improve our methodology for isolation of individual pachytene chromosomes as objects for mechanical studies. We will pursue our recent discovery of actin- and telomere-based chromosomal motion using existing reagents and by searching for "motion mutants". Defects in meiotic interhomolog interactions underlie many types of hereditary infertility as well as most chromosomal aneuploidies, all of which confer significant societal burdens (e.g. Downs syndrome). Basic understanding of these processes is crucial for diagnosis and potential amelioration of these conditions.