Regulation of a Spermatogenesis-Specific Gene

精子发生是一个动态的细胞分化过程，其显著特征是 基因表达模式。多年来，我们一直将精子发生特异性的Pgk2基因作为一种 一个严格调控的组织特异性基因在减数分裂和减数分裂后特异表达的模型 生精细胞。我们利用独一无二的生精细胞谱系获得了 特定生精细胞类型在减数分裂前、减数分裂和减数分裂后的纯化群体。这 使我们能够研究与转录调控机制相关的分子参数， 并确定导致启动转录的分子事件的发展顺序 Pgk2基因。这使得我们能够就其中涉及的机制提出可测试的假说 监管流程。在这一应用中，我们提出了实验来确定涉及到的关键因素 对该基因的调节，以表征在此之前染色质组成和结构的变化 这个基因的转录激活，最后，评估一个组织和基因- 在转录参数发生任何其他变化之前，该基因会形成特定的去甲基化结构域 并评估去甲基鸟蛋白在多大程度上预先处理转录激活 Pgk2基因在体内的表达。这些实验将使我们能够确定 与精子发生特异性基因转录激活相关的调节事件。这将是 加深对组织特异性基因表达调控机制的理解 一般的，特别是精子发生特异性的基因表达。

Spermatogenesis is a dynamic process of cellular differentiation that is marked by dramatic changes in patterns of gene expression. For many years we have studied the spermatogenesis-specific Pgk2 gene as a model of a tightly regulated tissue-specific gene expressed exclusively in meiotic and postmeiotic spermatogenic cells. We have exploited the uniquely accessible spermatogenic cell lineage to obtain purified populations of specific spermatogenic cell types at premeiotic, meiotic, and postmeiotic stages. This has allowed us to examine molecular paramters associated with mechanisms of transcriptional regulation, and to determine a developmental order of molecular events that lead up to initiation of transcription of the Pgk2 gene. This has allowed us to formulate testable hypotheses about the mechanisms involved in this regulatory process. In this application, we propose experiments to identify key factors involved in the regulation of this gene, to characterize changes in chromatin composition and structure that precede transcriptional activation of this gene, and, finally, to assess the mechanism by which a tisssue- and gene- specific demethylation domain develops in this gene prior to any other changes in transcriptional parameters and to assess the extent to which demethylaUon is required to predispose transcriptional activation of the Pgk2 gene in vivo. These experiments will allow us to define cause-and-effect relationships among regulatory events associated with transcriptional activation of a spermatogenesis-specific gene. This will lead to an enhanced understanding of the mechanisms that regulate tissue-specific gene expression in general, and spermatogenesis-specific gene expression in particular.