Mechanisms of heterochromatin targeting and epigenetic genome regulation

项目总结 这项研究计划的长期目标是在分子水平上确定非编码 RNAs(LncRNAs)参与染色质介导的基因沉默。许多lncRNA在细胞核中起作用 通过染色质调控机制的脚手架来调控基因表达。LncRNAs的鉴定 远远超过了详细的调查，因此管理这些由lncRNA介导的事件的机制是 还没有被很好地理解。我们将解决该领域的四个主要悬而未决的问题：1)lncRNAs如何 靶向基因组的特定区域？2)lncRNA是否需要结构重塑才能激活染色质 抑制机制？3)lncRNA如何有助于阻止基因转录？4)全程是什么？ IncRNA可以在染色质上搭建蛋白质相互作用的支架吗？我们的近期目标是专注于模型 LncRNA HOTAIR虽然较长期的目标将研究更多的LncRNA，但对此知之甚少。 HOTAIR是从一个发育调节的HOX基因簇转录而来的，它调节着许多基因在 通过Polycomb沉默复合体PRC2。我们最近的进展确定了一个新的关键角色 决定了HOTAIR功能的特异性，并提出了HOTAIR使用蛋白质的模型 “媒人”调节RNA-RNA碱基配对与目标基因的新生转录本之间的相互作用。我们 我将使用上面的问题来探讨此模型，以揭示此问题的新层次的机械细节 IncRNA。将采用多方面的方法，将生化重建与尖端技术相结合 蛋白质组学和基因组学，以揭示lncRNAs如何利用其RNA序列信息库来靶向 支架异染色质的形成。这些研究将为lncRNA在基因中的作用机制提供一个模型。 可能广泛适用于其他lncRNA途径的调控。我们还将重点介绍潜在的分子 靶向干扰HOTAIR活性，促进许多癌症的转移。 与公共卫生的相关性 长的非编码RNA是从人类基因组中最初被认为是“垃圾”DNA的区域产生的。 许多lncRNAs参与了基因调控的表观遗传机制，错误的调控可导致 癌症等疾病。因此，lncRNA显然是提供理解缺失环节的候选基因 许多人类疾病的分子机制，对于这些疾病来说，有一个“隐藏的遗传性”因素没有 但已被确认身份。

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.