P granules and control of germ cells development

描述（由申请人提供）：生殖细胞执行多细胞生物的生殖功能，正常的生殖细胞发育保证了物种的生存。生殖颗粒是生殖细胞中保守的细胞器，对生殖细胞的存活、分化和功能至关重要。在模式生物中，细菌颗粒成分的突变或其表达的丧失会导致不育，并与人类的不育有关。相比之下，体细胞中胚芽颗粒成分的不适当表达与人类的癌变有关。许多rna结合蛋白和发育调节的mRNA在胚芽颗粒中被发现富集，导致假设这些细胞器在调节mRNA稳定性或翻译活性方面起作用；然而，这些细胞器的分子功能仍不清楚。秀丽隐杆线虫对于理解生殖系发育的翻译调控具有重要意义。我们之前的研究表明秀丽隐杆线虫胚芽颗粒（P颗粒）对一种rna结合调节蛋白FBF-2对生殖系干细胞的调节有特定的贡献，但关于这种贡献的机制基础仍有很多需要了解。我们的实验系统准备在分子细节上解决这个问题。我们的研究将集中在FBF-2作为生殖颗粒在调节种系rna结合蛋白活性方面的一个范例。通过整合生化、分子、遗传和基于成像的方法，我们将：1)定义FBF-2调控复合物的特定成分；2)确定FBF-2的辅因子，这些辅因子依赖于P颗粒的完整性来与FBF-2组装；3)确定FBF-2介导P颗粒募集和FBF-2特异性调控活性的序列。这些研究将揭示细菌颗粒依赖性调控的一般机制。由于生殖颗粒是保守的细胞器，而FBF-2是保守的PUF蛋白家族的成员，因此该模型系统的研究将为了解人类不孕症的原因提供重要的见解。

DESCRIPTION (provided by applicant): Germ cells carry out the reproductive function of the multicellular organisms, and normal germ cell development ensures survival of the species. Germ granules are conserved cytoplasmic organelles of the germ cells, essential for the survival, differentiation, and function of these cells. Mutations in germ granule components or loss of their expression lead to infertility in model organisms and are associated with infertilityin humans. By contrast, inappropriate expression of germ granule components in somatic cells is linked to carcinogenesis in humans. Many RNA-binding proteins and developmentally regulated mRNAs are found enriched in the germ granules, leading to a hypothesis that these organelles function in regulation of mRNA stability or translational activity; yet, the molecular function of these organelles is still undefined. The nematode C. elegans has been instrumental for understanding translational regulation of germline development. Our previous studies demonstrated specific contribution of C. elegans germ granules (P granules) to the regulation exerted by an RNA-binding regulatory protein FBF-2 in germline stem cells, yet much remains to be learned about the mechanistic basics of this contribution. Our experimental system is poised to address this question in molecular detail. Our studies will focus on FBF-2 as a paradigm of germ granule contribution to regulating the activity of RNA-binding proteins in germline. By integrating biochemical, molecular, genetic, and imaging-based approaches, we will: 1) Define the specific components of the FBF-2 regulatory complex; 2) Identify the cofactors of FBF-2 that depend on P granule integrity for their assembly with FBF-2; 3) Determine the sequences of FBF-2 mediating P granule recruitment and FBF-2-specific regulatory activity. These studies will reveal general mechanisms of germ granule-dependent regulation. Since the germ granules are conserved organelles and FBF-2 is a member of conserved PUF protein family, studies in this model system will provide critical insight into the causes of infertility i humans.