Cell Cycle Regulation of Histone Gene Expression

摘要 进入S期是调控哺乳动物细胞增殖的关键事件。受控激活 组蛋白基因在G1/S期的表达是新生DNA染色质包装所必需的。我们的 项目已经确定HiNF-P是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/CDK2/p220NPAT途径和HNF一P缺乏症通过S期影响细胞周期进程。这个 HiNF-P的发现和表征代表了我们计划最重要的成就之一 拟议的研究将建立在这一主要结果的基础上，为细胞周期控制开辟一个新的维度。 我们的中心假设是Cyclin E/CDK2/p220NPAT/HiNF-P基因调节级联是一个 主要细胞周期途径，功能是获得组蛋白H4生物合成的能力 支持将DNA包装为染色质。为了解决这一假设，我们将结合生化、分子、 细胞和体内遗传策略，以确定HiNF-P/p220NPAT通路如何支持S阶段的激活和 进步。首先，我们将描述蛋白质相互作用结构域和翻译后修饰 控制HiNF-P/p220NPAT复合体的活性以及调节信号的原位整合 亚核部位(‘组蛋白位点小体’)，介导组蛋白基因转录和信使核糖核酸的加工 目标1)。然后我们将研究HiNF-P缺乏如何影响正常和肿瘤细胞的细胞周期进程和 解决与调节细胞增殖有关的HiNF-P相关机制(具体目标2)。要建立IN HiNF-P途径的活体相关性，我们将探讨HiNF-P是否对正常发育具有重要意义 活体胚胎发育和出生后生长(具体目标3)。提出的三个目标旨在 全面了解细胞周期蛋白在分子、细胞和生物学上的贡献 E/CDK2/p220NPAT/HiNF-P通路对正常和肿瘤细胞增殖的影响

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.