Meiotic chromosome synapsis and recombination in yeast.

描述（由申请人提供）：该应用程序解决了酵母减数分裂期间同源染色体之间的相互作用。(1)与dsb无关的配对。我们将使用FISH来探测与dsb无关的同源配对在R和g波段的相对丰度，与姐妹染色单体内聚的关系以及染色质结构蛋白的参与。我们将使用“捕获染色体构象”（3C）方法来确定配对接触的位点。我们将进行一项试点实验，以研究一种可能的新的配对缺陷突变检测方法。（二）重组的起始：DSB转变。我们将通过3C方法和遗传学研究来研究dsb前重组体是否与其潜在的染色体轴存在物理关联。我们还将使用3C方法来识别新生的DSB/伙伴相互作用，并探索同源/姐妹歧视。我们将进一步探索在任何给定减数分裂核的单个位点上可能发生的dsb数量的限制。（三）重组后期。我们将进一步探索影响交叉控制转变的突变体中的减数分裂，并注意温度的重要影响。我们将继续分析野生型和选择突变体的花束期。我们将继续分析Mlh3在减数分裂重组中的作用。我们将研究被怀疑影响粗线中期单端入侵向双Holliday连接转化的突变的表型。我们将继续研究在减数分裂过程中双霍利迪结的拓扑异构体。（四）减数分裂染色体的结构和机制。我们将进一步探索染色质/轴/姐妹的相互作用揭示了我们最近的研究。我们将使用3C方法来研究中期前期染色体的物理特性。我们将在体内研究突触复合体扭转的动力学。我们将开始开发方法，分离，分析和物理操作粗线染色体在体外。

DESCRIPTION (provided by applicant): This application addresses the interactions between homologous chromosomes during meiosis in yeast. (I) DSB-independent pairing. We will use FISH to probe DSB-independent homolog pairing with respect to relative abundance in R- and G-bands, relationship to sister chromatid cohesion and involvement of chromatin structure proteins. We will use "Capturing Chromosome Conformation" (3C) methodology to identify sites of pairing contacts. We will carry out a pilot experiment to investigate a possible new assay for pairing-defective mutants. (II) Initiation of recombination: the DSB transition. We will investigate whether pre-DSB recombinosomes are physically associated with their underlying chromosome axes by 3C methodology and genetic studies. We will also use 3C methodology to identify nascent DSB/partner interactions and to explore homolog/sister discrimination. We will further explore constraints governing the number of DSBs that can occur at a single locus in any give meiotic nucleus. (III) Later stages of recombination. We will further explore meiosis in mutants that affect the crossover control transition, with attention to important effects of temperature. We will continue analysis of the bouquet stage in wild type and selected mutants. We will continue analysis of the role of Mlh3 for meiotic recombination. We will examine the phenotypes of mutations suspected to affect conversion of single-end invasions to double Holliday junctions at mid-pachytene. And we will continue to investigate which topological isomer(s) of double Holliday junctions occur during meiosis. (IV) Meiotic chromosome structure and mechanics. We will further explore chromatin/axis/sister interplay revealed by our recent studies. We will use 3C methodology to investigate physical properties of mid-prophase chromosomes. We will examine the dynamics of synaptonemal complex twisting in vivo. We will begin to develop methods for isolating, analyzing and physically manipulating pachytene chromosomes in vitro.