Regulation of gene silencing by an imprinted non-coding RNA

描述(由申请人提供)：基因调控是一个复杂的过程，它协调了基因激活和基因沉默的准确时间和位置。基因组印迹是一种特殊的机制，通过这种机制，一个基因会显示出一个亲本等位基因的沉默。人类染色体11p15.5上的印迹区域及其在小鼠中的同源结构域由一组基因组成，这些基因在父亲的染色体上被反义非编码RNA Kcnq1ot1沉默。关于等位基因特异性沉默的分子机制以及非编码RNA在调节这一过程中的作用，人们知之甚少。这项建议将首先利用转基因RNA干扰技术来测试Kcnq1ot1在建立该基因座印记中的作用。在第二和第三个目标中，我们将研究允许某些基因逃脱沉默的表观遗传过程，应用生物信息学、生化和体内方法相结合的方法来确定该区域中的调控元件，这些调控元件物理上相互作用，并创建与沉默区域穿插的转录活性区域。识别印记建立和维持的分子机制将促进我们对人类生长缺陷和疾病的理解。 公共卫生相关性：印记KCNQ1结构域中的基因与Beckwith-Wiedemann综合征有关，后者会导致产前过度生长和易患癌症。印记缺失已被认为与几种人类肿瘤有关。这一建议将提供对等位基因特异性基因沉默中所部署的调控机制的更彻底的理解，并将深入了解这些机制如何在人类疾病中出错。

DESCRIPTION (provided by applicant): Gene regulation is a complex process that orchestrates the precise timing and location of both gene activation and gene silencing. Genomic imprinting is a specialized mechanism whereby a gene displays silencing of one parental allele. The imprinted region on human chromosome 11p15.5 and its homologous domain in the mouse consists of a cluster of genes that are silenced on the paternal chromosome by an antisense non-coding RNA, Kcnq1ot1. Very little is known of the molecular mechanisms involved in allele-specific silencing and the role of the non-coding RNAs in modulating this process. This proposal will first exploit transgenic RNA interference technology to test the role of Kcnq1ot1 in establishing imprinting at this locus. In the second and third aims, we will study the epigenetic processes that allow some genes to escape silencing, applying a combination of bioinformatic, biochemical and in vivo approaches to identify regulatory elements in this domain that interact physically and create transcriptionally active domains interspersed with the silenced regions. Identifying the molecular mechanisms underlying the establishment and maintenance of imprinting will advance our understanding of human growth defects and disease. PUBLIC HEALTH RELEVANCE: Genes in the imprinted Kcnq1 domain are involved in Beckwith-Wiedemann syndrome, which causes prenatal overgrowth and predisposition to cancer. Loss of imprinting has been implicated in several human neoplasias. This proposal will provide a more thorough understanding of the regulatory mechanisms deployed in allele-specific gene silencing and will give insight into how these mechanisms can go awry in human disease.