Control of Oocyte Maturation in C. elegans

描述（由申请人提供）：我们的目的是确定细胞间信号传导协调线虫C中减数分裂和受精的机制。优雅在有性生殖的动物中，卵母细胞在双线期或终变期停止，并对激素作出反应而恢复减数分裂（减数分裂成熟）。女性减数分裂I染色体分离错误是导致人类出生缺陷的主要原因。年龄相关的卵巢激素环境变化是一个可能的原因。我们的研究建立了C。线虫作为研究激素控制减数分裂成熟的遗传范式。C.线虫精子输出主要精子蛋白（MSP）激素以触发减数分裂成熟。一个重大的进步，在以前的奖励期间是我们的发现，G1 s-腺苷酸环化酶信号在卵泡样鞘细胞是必需的所有已知的MSP依赖的减数分裂成熟反应的生殖细胞。相比之下，VAB-1 MSP/Eph受体在卵母细胞中起非必需的作用，当MSP不存在时抑制减数分裂成熟。本申请的特定目的测试了减数分裂成熟的体细胞控制模型，其中鞘细胞控制卵母细胞反应。 AIM 1定义了鞘细胞如何接收MSP信号。我们将测试的假设，MSP结合多种G蛋白偶联受体（GPCRs），以促进减数分裂成熟。FRET测量将询问MSP是否激活鞘细胞中的G1 s-腺苷酸环化酶途径。一系列功能测试将检查鞘细胞表达的GPCR在减数分裂成熟中的作用。保守的MSP结合GPCR可以介导哺乳动物中MSP相关配体的信号传导。 目的2阐明鞘细胞是如何将MSP信号传递给卵母细胞的.我们将测试体细胞cAMP依赖性蛋白激酶A通过拮抗两个抑制途径促进减数分裂成熟的假设。基因测试将解决是否PKA是需要在鞘细胞减数分裂成熟和个别的ace-4抑制基因座功能下游的PKA。我们将从分子水平识别关键的抑制基因座。这些研究将确定鞘细胞如何将MSP的存在传达给卵母细胞。 目的3剖析减数分裂成熟所需的翻译控制机制。保守的锌指蛋白OMA-1和OMA-2（OMA蛋白）是减数分裂成熟所必需的。蛋白质组学分析表明，OMA蛋白质的功能作为转录后基因调控。我们将测试的假设，即OMA蛋白的功能，以抑制减数分裂成熟因子mRNA的翻译时，MSP是不存在的，但激活翻译时，MSP存在。我们将首先使用RNA结合蛋白免疫沉淀-微阵列分析鉴定OMA-核糖核蛋白中的mRNA。然后，我们将确定OMA蛋白，MSP信号传导，和OMA-核糖核蛋白组分对关键靶mRNA表达的影响。这些研究将为减数分裂成熟的翻译调控提供新的见解。

DESCRIPTION (provided by applicant): Our objective is to define the mechanisms by which intercellular signaling coordinates meiosis and fertilization in the nematode C. elegans. In sexually reproducing animals, oocytes arrest at diplotene or diakinesis and resume meiosis (meiotic maturation) in response to hormones. Chromosome segregation errors in female meiosis I are the leading cause of human birth defects. And age-related changes in the hormonal environment of the ovary are a suggested cause. Our research established C. elegans as a genetic paradigm for studying hormonal control of meiotic maturation. C. elegans sperm export the major sperm protein (MSP) hormone to trigger meiotic maturation. A major advance in the prior award period was our finding that G1s-adenylate cyclase signaling in the follicle-like sheath cells is required for all known MSP-dependent meiotic maturation responses in the germline. By contrast, the VAB-1 MSP/Eph receptor plays a non-essential role in the oocyte to inhibit meiotic maturation when MSP is absent. The Specific Aims of this application test a model for the somatic control of meiotic maturation in which the sheath cells control the oocyte response. AIM 1 defines how the sheath cells receive the MSP signal. We will test the hypothesis that MSP binds multiple G protein-coupled receptors (GPCRs) to promote meiotic maturation. FRET measurements will ask whether MSP activates the G1s-adenylate cyclase pathway in sheath cells. A series of functional tests will examine the role of sheath cell-expressed GPCRs in meiotic maturation. Conserved MSP-binding GPCRs may mediate the signaling of MSP-related ligands in mammals. AIM 2 elucidates how the sheath cells transduce the MSP signal to the oocyte. We will test the hypothesis that somatic cAMP-dependent protein kinase A promotes meiotic maturation by antagonizing two inhibitory pathways. Genetic tests will address whether PKA is required in the sheath cells for meiotic maturation and whether individual acy-4 suppressor loci function downstream of PKA. We will molecularly identify critical suppressor loci. These lines of investigation will define how the sheath cells communicate the presence of MSP to the oocyte. AIM 3 dissects translational control mechanisms required for meiotic maturation. The conserved zinc finger proteins OMA-1 and OMA-2 (OMA proteins) are redundantly required for meiotic maturation. Proteomic analyses suggest that OMA proteins function as post-transcriptional gene regulators. We will test the hypothesis that OMA proteins function to repress translation of meiotic maturation factor mRNAs when MSP is absent, but activate translation when MSP is present. We will first identify mRNAs in OMA- ribonucleoproteins using RNA-binding protein immunoprecipitation-microarray profiling. We will then determine the effects of OMA proteins, MSP signaling, and OMA-ribonucleoprotein components on expression of key target mRNAs. These studies will provide insights into translational regulation of meiotic maturation.