Regulation of germline proliferation and differentiation

描述(申请人提供)：拟议研究的长期目标是阐明动物生殖系生长和分化的细胞和分子控制。拟议的实验解决了生殖生物学的三个基本问题。首先，如何控制生殖细胞继续有丝分裂或进入减数分裂？其次，生殖细胞如何控制分化为精子或卵母细胞，以响应体细胞提示？第三，从生殖系干细胞到转轨扩增细胞再到减数分裂进入的转变是如何由干细胞生态位控制的？我们建议的实验集中在线虫种质上，它非常适合于解决这些基本问题的分子清晰度。这个模型的力量来自于它的实验可控性和已经奠定的丰富基础。单个细胞，远端末端细胞(DTC)，创造干细胞生态位，生殖细胞的命运由一个新兴的保守分子调控网络控制，包括GLP-1/Notch信号，FBF/PUF和FOG-1/CPEB RNA结合蛋白，GLD-2细胞质聚(A)聚合酶和MPK-1/MAP激酶等。事实上，在已知的情况下，保守的监管机构保留着保守的监管关系和生物学功能。例如，PUF蛋白控制线虫、苍蝇和可能还有人类的生殖系干细胞，PUF蛋白控制线虫和人类的MAPK表达。我们的具体目标是识别FBF靶基因并研究PUF对增殖和分化的保守调控；分析FOG-1/CPEB以剂量依赖的方式控制增殖和分化的分子机制；阐明FOG-3调控并研究FOG-3/ToB如何控制增殖和精子命运；研究GLD-2及其对生殖系命运的组合调控；以及研究生态位区域、运输扩增区段及其分子调控。统一的主题是，这些目标一起将描绘这些保守的蛋白质如何在调控网络中工作，以协调生殖系的生长和分化。此外，我们的研究承诺揭示在动物发育中广泛运作的一般机制，因为我们专注于保守的调节者及其对根本命运决定的控制。对生殖系命运决定的细胞和分子控制的阐明可能会揭示生殖系癌症和不孕不育这两个主要健康问题的机制基础。我们的研究还可能影响生殖细胞作为再生医学干细胞的潜在来源的使用。公共卫生相关性：这项建议调查生殖系干细胞、生殖系转运放大细胞和精子/卵母细胞决定的分子调控。当这些生殖系命运的调节者有缺陷时，会导致癌症或不孕，这是两个主要的健康问题。此外，生殖细胞很可能是再生医学的最终干细胞来源，以取代疾病或受伤个体的组织。

DESCRIPTION (provided by applicant): The long-term objective of the proposed research is to elucidate cellular and molecular controls of growth and differentiation in the animal germline. The proposed experiments address three fundamental problems of reproductive biology. First, how are germ cells controlled to continue mitosis or enter meiosis? Second, how are germ cells controlled to differentiate as sperm or oocyte in response to somatic cues? Third, how are the transitions from germline stem cell to transit-amplifying cell and then to meiotic entry controlled by the stem cell niche? Our proposed experiments focus on the C. elegans nematode germline, which is superbly poised to address these fundamental problems with molecular clarity. The power of this model derives from its experimental tractability and the rich foundation already laid. A single cell, the distal tip cell (DTC), creates the stem cell niche and germ cell fates are controlled by an emerging network of conserved molecular regulators, including GLP-1/Notch signaling, FBF/PUF and FOG-1/CPEB RNA-binding proteins, the GLD-2 cytoplasmic poly(A) polymerase and MPK- 1/MAP kinase, among others. Indeed, where known, the conserved regulators retain conserved regulatory relationships and biological functions. For example, PUF proteins control germline stem cells in nematodes, flies and probably humans, and PUF proteins control MAP kinase expression in both nematodes and humans. Our specific aims will identify FBF target mRNAs and investigate conserved PUF controls of proliferation and differentiation; analyze the molecular mechanism by which FOG-1/CPEB controls both proliferation and differentiation in a dose-dependent manner; elucidate fog-3 regulation and investigate how FOG-3/Tob controls both proliferation and the sperm fate; investigate GLD-2 and its combinatorial control of germline fates; and investigate the Niche Region, the Transit Amplifying Compartment and their molecular regulation. The unifying theme is that the aims together will delineate how these conserved proteins work within a regulatory network to orchestrate germline growth and differentiation. Moreover, our studies promise to reveal general mechanisms that operate broadly in animal development, because of our focus on conserved regulators and their control of fundamental fate decisions. The elucidation of cellular and molecular controls of germline fate decisions will likely shed light on the mechanistic basis of germline cancers and infertility, two major health problems. Our studies may also impact use of germ cells as a potential source of stem cells for regenerative medicine. PUBLIC HEALTH RELEVANCE: This proposal investigates the molecular regulation of germline stem cells, germline transit-amplifying cells and the sperm/oocyte decision. Regulators of these germline fates, when defective, cause cancer or infertility, two major health problems. Moreover, germ cells may well be the ultimate source of stem cells for regenerative medicine to replace tissues in diseased or injured individuals.