The Synapsis Checkpoint in C. elegans Meiosis

线虫减数分裂中的突触检查点

基本信息

批准号：
9103164
负责人：
Needhi Bhalla
金额：
$ 27.38万
依托单位：
UNIVERSITY OF CALIFORNIA SANTA CRUZ
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-09-01 至 2017-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9103164
关键词：
ATP phosphohydrolase Address Aneuploidy Apoptosis Apoptotic Behavior Binding Biochemical Caenorhabditis elegans Candidate Disease Gene Cell Cycle Cell Cycle Checkpoint Cell Death Cell Nucleus Cell division Cells Chromatin Chromosome Pairing Chromosome Segregation Chromosomes Congenital Abnormality DNA Damage Data Defect Diploid Cells Diploidy Down Syndrome Embryo Ensure Enzymes Event Family Fertilization Fluorescence Recovery After Photobleaching Gene Order Generations Genes Genetic Genetic Recombination Genetic Transcription Genome Germ Cells Goals Haploidy Histone H3 Histones Homologous Gene Human Inherited Investigation Klinefelter&apos s Syndrome Link Lysine Malignant Neoplasms Mediating Meiosis Methyltransferase Modeling Molecular Molecular Structure Monitor Mutation Orthologous Gene Pathway interactions Pattern Play Predisposition Production Prophase Proteins RNA Interference RNA interference screen Recruitment Activity Role Saccharomycetales Signal Transduction Site Spontaneous abortion Synaptonemal Complex System TP53 gene Testing Translating Work base chromatin modification daughter cell developmental disease egg genome integrity histone methyltransferase histone modification mutant novel prevent research study response sperm cell synaptic failure transcription factor tumor progression tumorigenesis zygote

项目摘要

DESCRIPTION (provided by applicant): Meiosis generates haploid gametes, such as sperm and eggs, 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 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 developmental disorders. We have identified a meiotic checkpoint that responds to defects in homolog synapsis, independent of a DNA 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 meiotic checkpoint gene, suggesting that the molecular mechanism that detects synaptic failure is conserved. Using a combination of genetic, biochemical and cytological approaches, we plan to further investigate the synapsis checkpoint. We will address how chromatin state(s) contributes to the ability of PCs to activate the synapsis checkpoint by studying the role of chromatin-modifying enzymes at these cis-acting sites. We will determine how the assembly of the synaptonemal complex (SC) is monitored during a normal meiosis by localizing PCH-2 in wildtype and mutant backgrounds, identifying proteins that interact with PCH-2 and investigating whether PCH-2 specifically modifies an important class of SC components. Furthermore, we will identify additional components of the checkpoint by undertaking an RNA interference screen that will focus on candidate genes that fulfill specific expression and phenotypic profile criteria. This screen has identified a putative transcription factor as a checkpoint component and we will test whether this factor directly regulates the core apoptotic machinery in response to checkpoint activation. These complementary approaches will enable us to gain a molecular and mechanistic understanding of how homolog synapsis is monitored during meiosis and how an unsynapsed or inappropriately synapsed homolog generates a checkpoint signal that is ultimately translated into an apoptotic response to avoid the production of aneuploid gametes.

描述（由申请人提供）：减数分裂从二倍体细胞中产生单倍体配子，例如精子和卵，因此受精后二倍体基因组恢复。减数分裂分裂期间染色体的适当分离取决于减数分裂预言中的事件，例如同源染色体的突触和跨界重组。染色体分离的错误通常对受精的合子致命，但也可能导致癌症易感或发育障碍。我们已经确定了一个减数分裂检查点，该检查点对同源性突触的缺陷做出了反应，独立于DNA损伤/重组检查点，并激活凋亡以避免产生非整倍型配子。并非所有未命名的序列都具有触发此检查点的能力。相反，该途径是由未结合配对中心（PC）的染色体位点专门激活的，这些染色体位点可以促进秀丽隐杆线虫中的突触。此外，该检查点需要C.秀杆秀丽隐杆线虫同源物PCH2，这是一种崭露头角的酵母减数分裂点基因，这表明检测到突触衰竭的分子机制是保守的。使用遗传，生化和细胞学方法的结合，我们计划进一步研究突触检查点。我们将通过研究染色质状态在这些顺式作用位点的作用来解决染色质状态如何促进PC激活突触检查点的能力。我们将通过将PCH-2定位在野生型和突变体背景中，确定与PCH-2相互作用并研究PCH-2是否专门修改重要类SC分量的蛋白质，从而确定如何通过将PCH-2定位在正常减数分裂过程中，在正常减数分裂过程中监测突发型复合物（SC）的组装。此外，我们将通过进行RNA干扰屏幕来确定检查点的其他组成部分，该屏幕将重点放在满足特定表达和表型概况标准的候选基因上。该屏幕已将推定的转录因子确定为检查点组件，我们将测试该因子是否直接调节核心凋亡机制以响应检查点激活。这些互补方法将使我们能够对减数分裂过程中如何监测同源性突触的分子和机械理解，以及如何使用非序列或不合适的突触同源物产生一个检查点信号，该检查点信号最终被转化为凋亡响应，以避免产生Aneuploid Gametes。