Gene Expression in the Preimplantation Mouse Embryo

描述（由申请人提供）：本申请的长期目标是确定在卵母细胞生长和母体-合子过渡期间控制基因表达变化的潜在机制，这两者是相互关联的，并且对发育至关重要。卵母细胞发育的一个普遍特征是在生长中期左右开始转录下降，使得完全生长的卵母细胞基本上是转录静止的。在小鼠中，这种下降与染色质结构的可见变化相关，染色质结构变得更加浓缩并降低了转录机制的活性。使用转基因RNAi方法，允许研究任何基因在卵母细胞发育中的功能，具体目标1将测试的假设，即染色质结合蛋白和UBC 9的HP 1家族的成员，通过其在sumoylation的核心作用，是必不可少的染色质结构和转录活性的变化，发生在卵母细胞生长。基因表达的主要重编程首先在2-细胞阶段被检测到，并且对于继续发育至关重要。叠加在基因组激活上的是染色质介导的转录抑制状态的发展。我们的转录谱分析实验确定Myc为基因组激活和基因表达重编程的关键候选基因，Hdad为建立转录抑制状态所必需。使用RNAi方法靶向Myc和Hdad，Specific Aim 2将测试Myc和Hdad对于这两个过程至关重要的假设，这两个过程共同塑造了基因组激活后成功发育所需的适当基因表达模式。卵母细胞表达miRNAs和mRNA降解，其在卵母细胞成熟期间开始并在早期植入前发育期间持续，是一种转录后机制，有助于决定胚胎中基因表达的整体模式。特异性目的3将检验以下假设：miRNA靶向特定mRNA以降解P体，并且该机制对于适当的卵母细胞/胚胎发育至关重要。拟议的研究将增加我们对人类发展的基本知识和理解。在短期内，它们可能有助于改善人类不孕症的治疗，提供新的知识，促进合理开发在辅助生殖技术（ART）实践中促进改善卵母细胞和植入前胚胎发育的治疗方法。

DESCRIPTION (provided by applicant): The long-term goal of this application is to determine underlying mechanisms that govern changes in gene expression during oocyte growth and the maternal-to-zygotic transition, both of which are linked and essential for development. A universal feature of oocyte development is that transcription declines commencing around mid-growth such that fully-grown oocytes are essentially transcriptionally quiescent. In mouse, this decline correlates with visible changes in chromatin structure, which becomes more condensed and decreased activity of the transcription machinery. Using a transgenic RNAi approach that permits study of the function of any gene in oocyte development, Specific Aim 1 will test the hypothesis that members of the HP1 family of chromatin-binding proteins and UBC9, via its central role in sumoylation, are essential for changes in chromatin structure and transcriptional activity that occur during oocyte growth. A major reprogramming of gene expression is first detected during the 2-cell stage and essential for continued development. Superimposed on genome activation is development of a chromatin-mediated transcriptionally repressive state. Our transcript profiling experiments identified Myc as a candidate gene pivotal for genome activation and reprogramming of gene expression, and Hdad as essential for establishing the transcriptionally repressive state. Using an RNAi approach to target Myc and Hdad, Specific Aim 2 will test the hypothesis that Myc and Hdad are critical for these two processes that collaboratively sculpt the appropriate pattern of gene expression required for successful development following genome activation. Oocytes express miRNAs and mRNA degradation, which initiates during oocyte maturation and continues during early preimplantation development, is a post-transcriptional mechanism that contributes to determining the global pattern of gene expression in the embryo. Specific Aim 3 will test the hypothesis that miRNAs target specific mRNAs for degradation in P-bodies and that this mechanism is essential for proper oocyte/embryo development. The proposed studies will increase our basic knowledge and understanding of human development. In the near term, they may help improve treatment of human infertility by providing new knowledge that will facilitate the rational development of treatments that foster improved oocyte and preimplantation embryo development in the practice of Assisted Reproductive Technology (ART).