Cell Cycle Regulation of Histone Gene Expression

摘要 进入S期是调节哺乳动物细胞增殖的关键事件。控制激活 组蛋白基因在G1/S期的表达对于新生DNA的染色质包装是必不可少的。我们 一个程序已经确定HiNF-P作为组蛋白基因的主要转录调节因子，组蛋白基因的终点分子， 细胞周期蛋白E/CDK 2/p220 NPAT途径，和HiNF-P缺陷损害细胞周期通过S期的进展。的 HiNF-P的发现和表征代表了我们项目最重要的成就之一 而这项研究将建立在这一主要成果的基础上，为细胞周期控制开辟一个新的方向。 我们的中心假设是，细胞周期蛋白E/CDK 2/p220 NPAT/ HiNF-P基因调控级联反应是一种细胞周期调节因子。 主要的细胞周期途径，其功能是实现组蛋白H4生物合成的能力， 支持DNA作为染色质包装。为了解决这个假设，我们将结合联合收割机的生化，分子， 确定HiNF-P/p220 NPAT通路如何支持S期活化的细胞和体内遗传策略， 进展首先，我们将描述蛋白质-蛋白质相互作用结构域和翻译后修饰， 控制HiNF-P/p220 NPAT复合物的活性，以及调节信号的原位整合， 介导组蛋白基因转录和mRNA加工的亚核位点（“组蛋白基因座体”）（特异性 目标1）。然后，我们将研究HiNF-P缺陷如何影响正常和肿瘤细胞的细胞周期进程， 解决参与调节细胞增殖的HiNF-P相关机制（具体目标2）。建立在 为了研究HiNF-P通路的体内相关性，我们将研究HiNF-P是否对正常发育很重要， 在胚胎发生和出生后生长过程中体内（具体目标3）。这三个拟议目标旨在 提供了一个完整的理解的分子，细胞和生物贡献的细胞周期蛋白 E/CDK 2/p220 NPAT/HiNF-P通路对正常和肿瘤细胞中细胞增殖的影响。

ABSTRACT Entry into S phase is a key event for regulation of mammalian cell proliferation. The controlled activation of histone gene expression at the G1/S phase transition is essential for chromatin packaging of nascent DNA. Our program has identified HiNF-P as the principal transcriptional regulator of histone genes, the end-point molecule for the cyclin E/ CDK2/ p220NPAT pathway, and HiNF-P deficiency impairs cell cycle progression through S phase. The discovery and characterization of HiNF-P represents one of the most important accomplishments of our program and the proposed studies will build on this major result to open a new dimension to cell cycle control. Our central hypothesis is that the cyclin E/ CDK2/ p220NPAT/ HiNF-P gene regulatory cascade is a principal cell cycle pathway that functions to achieve competency for histone H4 biosynthesis to support packaging of DNA as chromatin. To address this hypothesis, we will combine biochemical, molecular, cellular and in vivo genetic strategies to define how the HiNF-P/p220NPAT pathway supports S phase activation and progression. First, we will characterize protein-protein interaction domains and post-translational modifications that control the activity of the HiNF-P/p220NPAT complex, as well as the in situ integration of regulatory signals at subnuclear sites ('Histone Locus Bodies') that mediate histone gene transcription and mRNA processing (Specific Aim 1). We will then examine how HiNF-P deficiency affects cell cycle progression in normal and tumor cells and address HiNF-P related mechanisms involved in regulating cell proliferation (Specific Aim 2). To establish the in vivo relevance of the HiNF-P pathway, we will investigate whether HiNF-P is important for normal development in vivo during embryogenesis and post-natal growth (Specific Aim 3). The three proposed aims are designed to provide an integrated understanding of the molecular, cellular, and biological contributions of the cyclin E/CDK2/p220NPAT/HiNF-P pathway to cell proliferation in normal and tumor cells.