Mechanisms of heterochromatin targeting and epigenetic genome regulation

异染色质靶向和表观遗传基因组调控机制

• 批准号: 9142004
• 负责人: Aaron M. Johnson
• 金额: $ 36.71万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-16 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9142004
• 关键词: Address; Base Pairing; Biochemical; Cell Nucleus; Chromatin; Complex; Development; Disease; Epigenetic Process; Event; Gene Cluster; Gene Expression; Gene Expression Regulation; Gene Silencing; Gene Targeting; Genes; Genetic Transcription; Genome; Genomics; Goals; Heritability; Heterochromatin; Homeobox Genes; Human Genome; Investigation; Junk DNA; Lead; Link; Malignant Neoplasms; Mediating; Modeling; Molecular; Molecular Target; Neoplasm Metastasis; Pathway interactions; Polycomb; Proteins; Proteomics; Public Health; RNA; RNA Sequences; Regulation; Repression; Research; Scaffolding Protein; Specificity; Transcript; Untranslated RNA; human disease; programs; reconstitution; scaffold

PROJECT SUMMARY The long-term goals of this research program are to determine at a molecular level how long noncoding RNAs (lncRNAs) participate in chromatin-mediated gene silencing. Many lncRNAs act in the nucleus to regulate gene expression through scaffolding of chromatin regulatory machinery. The identification of lncRNAs far outpaces detailed investigations, hence the mechanisms that govern these lncRNA-mediated events are not yet well-understood. We will address four major outstanding questions in the field: 1) How do lncRNAs target specific regions of the genome? 2) Do lncRNAs require structural remodeling for activation of chromatin repression machinery? 3) How can a lncRNA contribute to halting gene transcription? 4) What is the full-extent that a lncRNA can scaffold protein interactions on chromatin? Our immediate goals are to focus on the model lncRNA HOTAIR while longer-term goals will investigate additional lncRNAs for which much less is known. HOTAIR is transcribed from one developmentally-regulated HOX gene cluster and regulates many genes in trans through the Polycomb silencing complex PRC2. Our recent progress has identified a new key player in dictating the specificity of HOTAIR function and has suggested a model where HOTAIR uses a protein "matchmaker" to mediate RNA-RNA base-pairing interactions with the nascent transcripts of target genes. We will approach this model using the questions framed above to uncover a new level of mechanistic detail for this lncRNA. A multi-faceted approach will be used, merging biochemical reconstitution with cutting edge proteomics and genomics, to uncover how lncRNAs use their reservoirs of RNA sequence information to target and scaffold heterochromatin formation. These studies will generate a model for lncRNA mechanism in gene regulation that may be broadly applicable to other lncRNA pathways. We will also highlight potential molecular targets to disrupt the HOTAIR activity that promotes metastasis in many cancers. Relevance to public health Long noncoding RNAs are produced from regions of the human genome originally thought to be "junk" DNA. Many lncRNAs participate in epigenetic mechanisms of gene regulation and mis-regulation can lead to diseases such as cancer. LncRNAs are therefore clear candidates to provide a missing link to understanding the molecular mechanisms of many human diseases for which there is a "hidden heritability" factor that has not yet been identified.

项目概要 该研究计划的长期目标是在分子水平上确定非编码的持续时间 RNA (lncRNA) 参与染色质介导的基因沉默。许多 lncRNA 在细胞核中发挥作用 通过染色质调节机制的支架调节基因表达。 lncRNA的鉴定 远远超过了详细的研究，因此控制这些 lncRNA 介导的事件的机制是 还没有很好地理解。我们将解决该领域的四个主要悬而未决的问题：1）lncRNA如何发挥作用？ 靶向基因组的特定区域？ 2) lncRNA是否需要结构重塑来激活染色质 镇压机器？ 3) lncRNA 如何有助于停止基因转录？ 4）什么是完整版 lncRNA 可以支撑染色质上的蛋白质相互作用吗？我们的近期目标是专注于模型 lncRNA HOTAIR，而长期目标将研究其他已知较少的 lncRNA。 HOTAIR 由一个发育调控 HOX 基因簇转录而来，并调控许多基因 反式通过 Polycomb 沉默复合物 PRC2。我们最近的进展已经确定了一个新的关键人物 规定了 HOTAIR 功能的特异性，并提出了 HOTAIR 使用蛋白质的模型 “媒人”介导RNA-RNA碱基配对与靶基因新生转录本的相互作用。我们 将使用上面提出的问题来处理该模型，以揭示该模型的新水平的机制细节 长链非编码RNA。将采用多方面的方法，将生化重组与尖端技术相结合 蛋白质组学和基因组学，揭示 lncRNA 如何利用其 RNA 序列信息库来靶向 和支架异染色质形成。这些研究将生成基因中lncRNA机制的模​​型 可能广泛适用于其他 lncRNA 途径的调节。我们还将强调潜在的分子 目标是破坏促进许多癌症转移的 HOTAIR 活性。 与公共卫生的相关性 长非编码RNA是由最初被认为是“垃圾”DNA的人类基因组区域产生的。 许多lncRNA参与基因调控的表观遗传机制，错误调控可能导致 癌症等疾病。因此，LncRNA 显然是提供理解缺失环节的候选者。 许多人类疾病的分子机制都存在一种“隐藏的遗传性”因素，而这种因素尚未被证实。 尚未被识别。