Histone Chaperones and Acetyltransferases in Chromatin Transitions

在每个真核细胞的细胞核内都有一个根本的悖论：遗传物质必须被组织和压缩，同时保持可被转录机器读出。组蛋白是这项任务的核心，最终将染色体DNA压缩数千倍以适应细胞核。基因组可及性部分是通过组蛋白伴侣和组蛋白乙酰转移酶(HATS)的作用实现的。组蛋白伴侣蛋白直接与组蛋白相互作用，可以在DNA上组装和/或分解它们。HATS共价修饰组蛋白，从而有可能改变染色质结构。这一项目的研究人员发现了组蛋白伴侣蛋白和组蛋白乙酰转移酶活性之间新的和令人兴奋的联系。然而，关于这些蛋白质共同作用管理基因组可及性的机制，人们几乎一无所知。该项目的目标是确定HATS和组蛋白伴侣蛋白的结构和功能之间的分子相互关系。这将通过测试三个共同的假设来实现，这允许在所有水平上进行多维和密集的研究(遗传、生物化学、热力学、酶和结构)。在项目1中，我们将研究组蛋白伴侣蛋白和HATS如何共同作用于从组装成核小体阵列的特定启动子DNA模板中驱逐组蛋白的生化基础。在项目2中，我们将继续研究与组蛋白伴侣蛋白相关的物理化学和结构，以及它们对乙酰化染色质的影响。在项目3中，我们将使用体内酵母遗传学和体外生物化学相结合的方法来研究组蛋白伴侣和HATS的遗传和物理相互作用。通过三个研究项目的整合，信息和试剂的交换，以及生物物理、蛋白质表达和纯化(PEP)和管理核心的重大贡献，该计划产生的结果将深刻影响我们对基因组可及性如何通过调节染色质动态来调节的理解。

There is a fundamental paradox within the nucleus of every eukaryotlc cell: the genetic material must be organized and compacted, while remaining accessible for readout by the transcription machinery. Histone proteins are at the core of this task and ultimately compact the chromosomal DNA thousands of fold to fit into the nucleus. Genome accessibility can be achieved in part by the actions of histone chaperones and histone acetyltransferases (HATs). Histone chaperones interact directly with histones and can assemble and/or disassemble them on DNA. HATs covalently modify the histones and thereby have the potential to alter chromatin structure. The investigators on this PROGRAM OF PROJECTS have discovered new and exciting linkages between the activities of histone chaperones and histone acetyltransferases. However, virtually nothing is known about the mechanisms by which these proteins work together to manage genome accessibility. The goal of this PROGRAM OF PROJECTS is to determine the molecular interrelationships between the structure and function of HATs and histone chaperones. This will be accomplished by testing three shared hypotheses, which allows for a multi-dimensional and intensive investigation at all levels (genetically, biochemically, thermodynamically, enzymatically, and structurally). In PROJECT 1, we will investigate the biochemical basis for how the histone chaperones and HATs function together to evict histones from a specific promoter DNA template assembled into nucleosomal arrays. In PROJECT 2, we will pursue physicochemical and structural studies related to histone chaperones and their effect on acetylated chromatin. In PROJECT 3, we will use a combination of in vivo yeast genetics and in vitro biochemistry to study the genetic and physical interactions of histone chaperones and HATs. Through the integration of the three research projects, the exchange of information and reagents, and the significant contributions of the Biophysics, Protein Expression and Purification (PEP) and Administrative Cores, the results generated from this Program will profoundly impact our understanding of how genome accessibility is regulated by modulating chromatin dynamics.