Histones and Nucleosomes in Archaea

古细菌中的组蛋白和核小体

• 批准号: 6778039
• 负责人: JOHN NEWTON REEVE
• 金额: $ 28.11万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6778039
• 关键词: Archaea; DNA binding protein; Escherichia coli; X ray crystallography; biochemical evolution; chromatin immunoprecipitation; circular DNA; crystallization; dimer; gene expression; genome; histones; intermolecular interaction; microarray technology; microorganism genetics; molecular assembly /self assembly; nucleic acid sequence; nucleosomes; polymerase chain reaction; protein folding; protein localization; protein structure function; recombinant proteins; species difference

DESCRIPTION (provided by applicant): Archaeal histones share a common ancestry with the histone-folds of the eukaryotic nucleosome cores histones and subunits of many large eukaryotic transcription factors. The histone fold is a structural motif that directs dimer formation, and archaeal histones form homodimers and heterodimers but eukaryotic histone folds now form only heterodimers. Archaeal histones also bind DNA and assemble into complexes spontaneously and individually, and can wrap DNA in either a negative or positive supercoil. They therefore provide a unique opportunity, and a practical experimental system to establish the molecular determinants of histone:histone and histone:DNA interactions. The experiments proposed will generate a detailed structural understanding of histone fold partner specificity, histone-DNA affinity, the positioning of histone assembly, and the determinants of the direction of DNA supercoiling. These are all issues of central and fundamental importance to understanding genome organization and the roles of histones and histone foldcontaining complexes in regulating gene expression in Eukaryotes, and in Archaea. The information gained will also be of importance in understanding how defects in these molecular assemblies and interactions negatively impact human development and health. We have established that different archaeal histone assemblies have sequence-dependent differences in DNA affinity, and this suggests an entirely novel concept for gene regulation based on alternative histone dimer assembly. Chromatin immunoprecipitation coupled with DNA microarray hybridization will be used to investigate this new idea, and to test the hypothesis that this archaeal histone regulatory system was the foundation for eukaryotic genome silencing and gene regulation by positioned nucleosome assembly.

描述（由申请人提供）：古菌组蛋白与真核核小体核心组蛋白的组蛋白折叠和许多大型真核转录因子的亚基具有共同的祖先。组蛋白折叠是指导二聚体形成的结构基序，古细菌组蛋白形成同二聚体和异二聚体，但真核组蛋白折叠现在仅形成异二聚体。古细菌组蛋白还结合 DNA 并自发地单独组装成复合物，并且可以将 DNA 包裹在负超螺旋或正超螺旋中。因此，它们提供了一个独特的机会和一个实用的实验系统来建立组蛋白：组蛋白和组蛋白：DNA 相互作用的分子决定因素。所提出的实验将对组蛋白折叠伙伴特异性、组蛋白-DNA 亲和力、组蛋白组装的定位以及 DNA 超螺旋方向的决定因素产生详细的结构理解。这些都是了解基因组组织以及组蛋白和含组蛋白折叠复合物在调节真核生物和古细菌基因表达中的作用的核心和根本重要性问题。获得的信息对于理解这些分子组装和相互作用的缺陷如何对人类发展和健康产生负面影响也很重要。我们已经确定，不同的古细菌组蛋白组装体在 DNA 亲和力方面具有序列依赖性差异，这提出了基于替代组蛋白二聚体组装的基因调控的全新概念。染色质免疫沉淀与 DNA 微阵列杂交相结合将用于研究这一新想法，并检验这一假设，即这种古菌组蛋白调节系统是真核基因组沉默和通过定位核小体组装进行基因调节的基础。