Characterization of the Synapis Checkpoint in C. elegans Meiosis

减数分裂从二倍体细胞产生单倍体配子，从而恢复二倍体基因组。 受精。减数分裂过程中染色体的适当分离取决于 减数分裂前期，如同源染色体的配对和联会和交换 重组。染色体分离的错误通常对受精卵是致命的，但也可能导致 癌症易感性或严重发育障碍。我已经确定了一个减数分裂检查点 对同源突触中的缺陷做出响应，独立于DMA损坏/重组检查点，以及 激活细胞凋亡以避免产生非整倍体配子。并不是所有未突触的序列都具有 触发这个检查点的能力；相反，这条通路是由非突触配对专门激活的 在线虫中，促进突触的染色体中心(PC)。此外，检查站 需要线虫PCH2的同源物，PCH2是一种发芽酵母粗线期检查点基因，这表明 检测突触失败的分子机制被广泛保守。 我计划进一步描述这个突触检查站的特征。我特别感兴趣的是筹委会对 突触检查点激活。与因子相互作用的蛋白质的鉴定和特性 PC功能所需的功能将提供有关该基因座在未突触时如何激活检查点的深入了解。 关于异染色质在非突触染色体上的调节以及PC如何 还将执行禁止DMA损坏检查点。我将确定联会的作用 突触检查点中的复合体(SC)通过表征两个与SC相互作用的基因并似乎 通过初步的RNA干扰(RNAi)实验，检查点需要。我会调查 已知的检查点组件PCH-2的功能和调节；GFP-PCH-2融合蛋白将被 定位于各种遗传背景，并提供了一种试剂来鉴定相互作用的蛋白质 生化方面的。此外，我将通过实施RNAi来确定检查站的其他组件 将重点放在满足特定表达和表型特征标准的候选基因的筛选。 这些互补的方法将使我能够从分子和机制上了解 同源突触被监控，以及未突触或不适当突触的同源如何产生 最终转化为细胞凋亡反应的检查点信号。 减数分裂产生配子，如卵子和精子。检查点监控减数分裂事件，以确保 配子有正确数目的染色体。如果配子的染色体数目不正确， 受精产生的胚胎通常是不能存活的。偶尔，胚胎会继承额外的 不致命但可能导致癌症易感性或严重发育缺陷的染色体。

Meiosis generates haploid gametes from a diploid cell such that a diploid genome is restored upon fertilization. The proper segregation of chromosomes during the meiotic divisions depends on events in meiotic prophase, such as the pairing and synapsis of homologous chromosomes and crossover recombination. Errors in chromosome segregation are usually fatal to the fertilized zygote but can also result in cancer predisposition or serious developmental disorders. I have identified a meiotic checkpoint that responds to defects in homolog synapsis, independent of a DMA damage/recombination checkpoint, and activates apoptosis to avoid the generation of aneuploid gametes. Not all unsynapsed sequences have the capacity to trigger this checkpoint; rather, this pathway is specifically activated by unsynapsed Pairing Centers (PCs), chromosome sites that promote synapsis in C. elegans. Furthermore, the checkpoint requires the C. elegans homolog of PCH2, a budding yeast pachytene checkpoint gene, suggesting that the molecular mechanism that detects synaptic failure is widely conserved. I plan to further characterize this synapsis checkpoint. I am particularly interested in the PC's contribution to synapsis checkpoint activation. The identification and characterization of proteins that interact with factors required for PC function will provide insight into how this locus activates the checkpoint when unsynapsed. Studies that address the regulation of heterochromatin on unsynapsed chromosomes and how the PC may inhibit the DMA damage checkpoint will also be undertaken. I will determine the role of the synaptonemal complex (SC) in the synapsis checkpoint by characterizing two genes that interact with the SC and appear to be required for the checkpoint by preliminary RNA inteferference (RNAi) experiments. I will investigate the function and regulation of the known checkpoint component, pch-2; a GFP-PCH-2 fusion protein will be localized in a variety of genetic backgrounds as well as provide a reagent to identify interacting proteins biochemically. Furthermore, I will identify additional components of the checkpoint by undertaking an RNAi screen that will focus on candidate genes that fulfill specific expression and phenotypic profile criteria. These complementary approaches will enable me to gain a molecular and mechanistic understanding of how homolog synapsis is monitored and how an unsynapsed or inappropriately synapsed homolog generates a checkpoint signal that is ultimately translated into an apoptotic response. Meiosis produces gametes, such as eggs and sperm. Checkpoints monitor meiotic events to ensure that gametes have the correct number of chromosomes. If a gamete has an incorrect number of chromosomes, the embryo that results from fertilization is often inviable. Occasionally, an embryo inherits an extra chromosome that is not lethal but can cause cancer predisposition or serious developmental defects.