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pRB and changes in the chromatin landscape during myogenic differentiation

pRB 和生肌分化过程中染色质景观的变化

基本信息

批准号：
8238898
负责人：
Brian D Dynlacht
金额：
$ 36.93万
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：
2003
资助国家：
美国
起止时间：
2003-02-01 至 2016-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8238898
关键词：
Ablation Affect Binding Bypass Cell Cycle Cell Cycle Progression Cells Chromatin Complex Coupled Cues DNA DNA Methylation Data Data Set Deposition E2F transcription factors Enabling Factors Enzymes Epigenetic Process Event Excision Funding Gene Expression Gene Expression Regulation Gene Silencing Gene Targeting Genes Goals Growth Histone Deacetylase Histone H2B Histone H3 Histones Immunoprecipitation Investigation Lead Link Lysine Maintenance Malignant Neoplasms Maps Mediating Methods Methylation Methyltransferase Modeling Molecular Profiling Mono-S Muscle Muscle Fibers Myoblasts PRC1 Protein Phase Play Polycomb Process Proteins RBL2 gene Recruitment Activity Regulation Regulator Genes Retinoblastoma Retinoblastoma Protein Role Signal Transduction Staging Structure System Testing Time Tissues Tumor Suppressor Proteins Withdrawal Work base cdc Genes chromatin immunoprecipitation chromatin modification gene repression genome-wide histone methyltransferase histone modification mutant myogenesis novel p107 protein research study retinoblastoma tumor suppressor

项目摘要

DESCRIPTION (provided by applicant): The retinoblastoma tumor suppressor (pRB) and two related proteins (P107 and P130; collectively referred to as pocket proteins) playa fundamental role in regulating proliferation, cell cycle progression, and cell cycle exit. pRB has also been shown to play an essential role in differentiation of several tissues, including muscle. Nevertheless, our understanding of the regulatory controls involving the transition from a proliferative to a quiescent and, finally, terminally differentiated state is incomplete. Our work during the previous funding period has focused on the unique roles for each of these pocket proteins in responding to growth arrest cues and in both promoting and maintaining differentiation of muscle. In addition, we have identified transcriptional and epigenetic regulatory mechanisms associated with cell cycle exit and terminal differentiation. In particular, we have begun a systematic investigation of all chromatin modifications associated with myogenic differentiation using a combination of ChIP-sequencing (ChIP-seq) and expression profiling. Here, we propose the following aims to further dissect the mechanisms underlying pocket protein involvement in cell cycle exit and differentiation. In our first Aim, we will examine gene regulation during myogenic differentiation by specifically focusing on the role of histone H2B ubiquitylation (H2BUb) during differentiation. We will examine the extent of histone cross-talk in myotubes and investigate the impact of ablating RNF20, the enzyme responsible for H2B ubiquitylation, on differentiation. Remarkably, we have found that H2BUb essentially disappears during differentiation, and therefore we will examine the underlying mechanistic basis for myotube-specific loss of H2Bub. In our second Aim, we will examine the genome-wide role of pRB and co-repressors in directing chromatin modifications. We will first perform ChIP-seq on pRB and P130 in differentiated myotubes, enabling us to identify regions bound by these factors. We will also perform expression profiling after removal of pRB or P130 from myotubes. By merging these data, we will determine how chromatin modifications and gene expression are affected by loss of pocket proteins. Using our extensive ChIPseq data as a guide, we will test the hypothesis that pRB directs tri-methylation of H3K27 (H3K27IDe3) and ask whether Polycomb repressive complex (PRC2) is involved and to what extent. We will examine whether Ezh2 or an alternative histone methyltransferase (HMT), such as Ezhl, may be involved in H3K27me3 deposition. We will determine whether pRB influences the recruitment of either or both HMTs. The acquisition of our extensive ChIP-seq dataset allows us an unprecedented ability to examine on a genome-wide scale the relationship between pRB binding, chromatin modifications, and gene expression in a developmentally relevant setting, thereby enhancing our understanding of regulatory controls that are essential for both reversible and permanent gene silencing, withdrawal from the cell cycle, and muscle differentiation. PUBLIC HEALTH RELEVANCE: Cancer results in some cases when cells fail to properly differentiate. Differentiation is coupled to exit from the cell cycle, and the retinoblastoma (pRB) tumor suppressor and E2F transcription factor play pivotal roles in controlling growth arrest and differentiation. pRB and associated proteins regulate these processes in part by directing chromatin modifications. Using muscle differentiation as a model, this proposal seeks to understand the underlying pRB-dependent and pRB-independent mechanisms that drive chromatin modifications, regulate gene expression, and thereby control the decision to permanently stop dividing and to terminally differentiate.

描述（由申请人提供）：