PROLIFERATIVE VS MEIOTIC FATE DECISION IN C. ELEGANS

线虫增殖与减数分裂的命运决定

• 批准号: 9340215
• 负责人: TIM SCHEDL
• 金额: $ 37.52万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-02-01 至 2020-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9340215
• 关键词: Address; Adult; Animal Model; Animals; Area; Binding; Biochemical; Biological Assay; Caenorhabditis elegans; Cell Differentiation process; Cell Nucleus; Cell Proliferation; Cells; ChIP-seq; Cleaved cell; Complex; DNA Binding; Data; Development; Distal; Functional disorder; Gametogenesis; Genes; Genetic Transcription; Genetic Translation; Germ Cells; Homeostasis; Infertility; Investigation; Knowledge; Lead; Malignant Neoplasms; Mass Spectrum Analysis; Mediating; Meiosis; Messenger RNA; Mitotic; Modeling; Molecular; Molecular Genetics; Output; Pathway interactions; Pattern; Phosphotransferases; Population; Post-Transcriptional Regulation; Process; Proliferating; Property; Proteins; Regulation; Repression; Research; Route; Signal Transduction; Stem cells; Sterility; Study models; System; Testing; Tissues; Transcriptional Regulation; Ubiquitin; experimental study; gene function; gene product; genetic analysis; germline stem cells; glucagon-like peptide 1; mRNA Stability; notch protein; stem; stem cell fate; stem cell population; tumor

Project Summary An essential decision that germline stem cells must make is to proliferate mitotically or initiate meiotic development/gametogenesis. Disruption of this developmental switch can result in infertility and in some cases germline tumors. The C. elegans adult hermaphrodite is an important model for understanding control of the switch from germline stem cell fate to meiotic development/gametogenesis, where an outline of the process is emerging. Niche dependent GLP-1 Notch signaling promotes the stem cell fate and represses three redundant pathways that promote meiotic development/gametogenesis: the GLD-1 pathway (which represses expression of proliferation genes), the GLD-2 pathway (which promotes expression of meiotic genes), and a 3rd pathway whose existence has been revealed through genetic analysis but no gene products have been identified to date. At a cellular level, we have recently shown that the stem cell population is large and germ cells enter meiosis directly, without intervening transit-amplifying divisions. The absence of transit-amplifying divisions simplifies the analysis allowing straightforward assays to identify genes involved in repressing meiosis in stem cells and repressing proliferation at meiotic entry and is the primary reason why C. elegans is the major animal model for studying this important developmental switch. This proposal addresses three major areas in the stem cell - meiotic development/gametogenesis switch where there are large gaps in our knowledge. First, the transcriptional targets of GLP-1 signaling that promote the stem cell fate and/or repress the meiotic entry pathways are incompletely known. We propose to identify GLP-1 transcriptional targets and determine which meiotic entry pathway(s) they inhibit. Second, genes that constitute the 3rd meiotic entry pathway are unknown. Our preliminary results indicate that the SCFprom-1 ubiquitin mediated degradation complex is the 3rd pathway and we propose experiments to further test this hypothesis. Third, gld-1 mRNA translation/stability regulation is a central part of germline stem cell differentiation as expression must be repressed in stem cells and activated for meiosis; however control of GLD-1 accumulation is incompletely understood. We propose to (i) determine the mechanism of how two known GLP-1 transcriptional targets repress GLD-1 accumulation, (ii) determine the spatial and quantitative contribution of newly identified regulators of the germline stem cell differentiation in control of GLD-1 accumulation, and (iii) identify new regulators, since known regulators explain only part of the GLD-1 accumulation pattern, as a route to identify additional genes that control the developmental switch.

项目概要 生殖系干细胞必须做出的一个重要决定是进行有丝分裂增殖或启动减数分裂 发育/配子发生。这种发育开关的破坏可能会导致不孕，在某些情况下 种系肿瘤。线虫成年雌雄同体是理解控制的重要模型 从生殖干细胞命运转变为减数分裂发育/配子发生，该过程的概述是 正在出现。生态位依赖性 GLP-1 Notch 信号传导促进干细胞命运并抑制三个冗余 促进减数分裂发育/配子发生的途径：GLD-1 途径（抑制表达） 增殖基因）、GLD-2 途径（促进减数分裂基因的表达）和第三条途径 其存在已通过遗传分析揭示，但尚未鉴定出任何基因产物 日期。在细胞水平上，我们最近表明干细胞群体很大，并且生殖细胞进入 直接减数分裂，无需干预转运放大分裂。缺乏转运放大部门 简化了分析，允许直接进行测定来识别参与抑制茎减数分裂的基因 细胞并抑制减数分裂进入时的增殖，这是秀丽隐杆线虫成为主要动物的主要原因 研究这一重要发育转变的模型。 该提案涉及干细胞的三个主要领域——减数分裂发育/配子发生转换 我们的知识存在很大差距。首先，GLP-1信号传导的转录靶点促进 干细胞命运和/或抑制减数分裂进入途径尚不完全清楚。我们建议确定 GLP-1 转录目标并确定它们抑制哪些减数分裂进入途径。其次，基因 构成第三次减数分裂进入途径尚不清楚。我们的初步结果表明 SCFprom-1 泛素介导的降解复合物是第三条途径，我们提出实验来进一步测试这一点 假设。三、gld-1 mRNA翻译/稳定性调节是生殖干细胞的核心部分 分化，因为表达必须在干细胞中被抑制并被激活以进行减数分裂；然而控制 GLD-1 的积累尚不完全清楚。我们建议 (i) 确定两个机制如何 已知的 GLP-1 转录靶点抑制 GLD-1 积累，(ii) 确定空间和定量 新发现的生殖系干细胞分化调节因子对 GLD-1 控制的贡献 积累，以及 (iii) 确定新的监管机构，因为已知的监管机构仅解释了 GLD-1 的部分内容 积累模式，作为识别控制发育开关的其他基因的途径。