Mechanisms of heterochromatin targeting and epigenetic genome regulation

项目摘要 这项研究计划的长期目标是在分子水平上确定非编码的 RNA（lncRNA）参与染色质介导的基因沉默。许多lncRNA在细胞核中起作用， 通过染色质调节机制的支架来调节基因表达。lncRNA的鉴定 远远超过了详细的调查，因此，管理这些lncRNA介导的事件的机制是 还没有被很好地理解。我们将解决该领域中四个主要的悬而未决的问题：1）lncRNA如何 针对基因组的特定区域2)lncRNA是否需要结构重塑来激活染色质 镇压机器3)lncRNA如何阻止基因转录？4)什么是全图 lncRNA可以在染色质上支持蛋白质相互作用我们的近期目标是专注于模型 lncRNA HOTAIR，而长期目标将研究更多的lncRNA，这些lncRNA知之甚少。 HOTAIR是从一个发育调控的HOX基因簇转录的，并在发育过程中调控许多基因。 通过Polycomb沉默复合物PRC 2反式表达。我们最近的进展确定了一个新的关键参与者， 指出了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碱基配对与靶基因的新生转录本的相互作用。我们 我将使用上面提出的问题来接近这个模型，以揭示这个模型的新的机械细节水平。 lncRNA。一个多方面的方法将被使用，合并生化重建与尖端 蛋白质组学和基因组学，以揭示lncRNA如何使用其RNA序列信息库靶向 和支架异染色质形成。这些研究将为lncRNA在基因表达中的作用机制提供一个模型 这可能广泛适用于其他lncRNA途径的调控。我们还将强调潜在的分子 靶向破坏促进许多癌症转移的HOTAIR活性。 与公共卫生的相关性 长的非编码RNA是由人类基因组中最初被认为是“垃圾”DNA的区域产生的。 许多lncRNA参与基因调控的表观遗传机制，并且错误调控可导致 疾病，如癌症。因此，lncRNA是明确的候选者，以提供理解缺失的环节。 许多人类疾病的分子机制，其中有一个“隐藏的遗传性”因素， 尚未被确认。

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.