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Structural and functional analysis of gene silencing

基因沉默的结构和功能分析

基本信息

批准号：
9272105
负责人：
Karim Jean Armache
金额：
$ 12.21万
依托单位：
NEW YORK UNIVERSITY SCHOOL OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-07-17 至 2020-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9272105
关键词：
Address Base Pairing Binding Binding Proteins Biochemical Biological Assay Biological Models Biological Process Centromere Chromatin Chromatin Modeling Chromatin Structure Complement Complex Cryoelectron Microscopy DNA DNA Packaging Data Development Disease Epigenetic Process Eukaryota Fission Yeast Gene Expression Profile Gene Expression Regulation Gene Silencing Genetic Genetic Transcription Genome Health Heterochromatin Higher Order Chromatin Structure Histone H3 Histones Homologous Gene Human In Vitro Inflammation Laboratories Lysine Maintenance Malignant Neoplasms Mating Types Mediating Methods Methylation Molecular Neurodegenerative Disorders Nucleosomes Play Positioning Attribute Post-Translational Protein Processing Process Processed Genes Proteins Refractory Regulation Role Saccharomyces cerevisiae Saccharomycetales Science Staging Stem Cell Development Structure Testing Work X-Ray Crystallography Yeasts base biophysical techniques design gene repression heterochromatin-specific nonhistone chromosomal protein HP-1 in vitro Model in vivo insight interest novel therapeutics protein complex reconstitution research study self-renewal success three dimensional structure tool yeast genetics

项目摘要

DESCRIPTION (provided by applicant): The process of gene silencing is conserved from yeast to humans, playing a crucial function in establishment, maintenance and propagation of distinct patterns of gene expression. Gene silencing plays a pivotal role in development, stem cell self-renewal and differentiation, and its dysregulation can cause developmental diseases, neurodegenerative disorders, inflammation as well as cancer. In all eukaryotes, spatial and temporal regulation of gene activity is directed by packaging of DNA into chromatin. The fundamental repeating unit of chromatin is the nucleosome that comprises 146 base pairs of DNA wrapped around an octamer of histone proteins. The nucleosome is the platform upon which proteins and protein complexes assemble to regulate chromosomal transactions such as gene transcription. Of particular interest to us are proteins and protein complexes that bind to nucleosomes to create epigenetically silent chromatin domains, their regulation by posttranslational modifications of histones and their effect on higher-order chromatin structure. Yeast has been instrumental in studying the establishment and maintenance of silent chromatin. Two widely studied and essential components of gene silencing in yeast are the Silent Information Regulator (SIR) complex in S. cerevisiae and Heterochromatin Protein 1 (HP1) in S. pombe. These proteins can bind nucleosomes - a process regulated in part by posttranslational modifications of histones - and spread across chromatin in a sequence independent fashion, establishing a chromatin structure that is refractory to transcription. The detailed mechanisms involved in these processes are largely unknown. To address this critical gap in the field of gene silencing, we will use structural and functional approaches. In AIM 1 we will determine three- dimensional structures of Sir3 (the core component of the SIR complex) in complex with the nucleosome and with the chromatin array. In AIM 2 we will determine the structure of fission yeast HP1 (Swi6) in complex with the chromatin substrate bearing histone H3 lysine 9 methylation. We will complement these structures with functional in vitro and in vivo experiments. The structural and functional studies of Sir3 and Swi6 in complex with nucleosomes will uncover the general principles underlying the assembly and spreading of these proteins on chromatin. Additionally we will investigate whether and how binding and spreading results in higher-order folding or compaction of chromatin. Our proposed comprehensive studies will provide crucial insights into the fundamental biological process of chromatin compaction and ultimately gene repression, and will provide invaluable insights into how deregulation of these complexes and chromatin structure contributes to disease.