Regulation of X-Inactivation by Non-Coding RNA Loci

非编码 RNA 位点对 X 失活的调控

• 批准号: 6994242
• 负责人: JEANNIE T LEE
• 金额: $ 13.13万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6994242
• 关键词: RNA interference; alleles; antisense nucleic acid; binding sites; biotechnology; chromatin; embryonic stem cell; female; fluorescent in situ hybridization; functional /structural genomics; gene induction /repression; gene interaction; genetic regulation; genetic transcription; genetically modified animals; genomic imprinting; laboratory mouse; molecular genetics; nucleic acid methylation; polymerase chain reaction; quantitative trait loci; sex chromosomes; sex linked trait; tissue /cell culture

Mammals achieve dosage compensation by transcriptional silencing of one X-chromosome in early female development. X-chromosome inactivation (XCI) is controlled by a master locus known as the "X-inactivation center," a cis-acting center which is both necessary and sufficient to direct X-chromosome counting, choice, and initiation of silencing. Our long term goal is to understand the molecular underpinnings of each step. It is currently known that Xist RNA, a non-coding product of the X-inactivation center, "paints" the inactive X and is required to initiate global silencing of that X. Work from the last funding period led to the discovery of two novel non-coding RNA loci at the X-inactivation center. Tsix, a gene antisense to Xist, inhibits Xist expression and designates the future active X. Xite, a locus associated with low-level intergenic transcripts, positively regulates Tsix expression. Thus, all known regulatory elements at the X-inactivation center make non-coding RNA. The proposed research will dissect the mechanism of action by Tsix and Xite. Specifically, the proposed research will (1) determine how Xite and Tsix inhibit the spread of Xist RNA, (2) define the molecular basis of X-inactivation imprinting and choice, and (3) test if Xite is the Xce ("X-controlling element"), the long-elusive modifier of XCI allele ratios which has been implicated in unfavorable skewing of XCI in female carriers of X-linked disease. As one of very few antisense loci in mammals, Tsix serves as a paradigm for antisense regulation. As one of only two known functional intergenic transcription elements in mammals, Xite will advance a limited knowledge of this emerging intergenic phenomenon. Information gained from the research program will also have significant impact on human genetics, cancer, and animal cloning, as well as on the basic biology of chromosomes, chromatin structure, and transcriptional regulation.

哺乳动物通过在早期女性发育中对一个X染色体的转录沉默来实现剂量补偿。 X染色体灭活（XCI）由称为“ X灭活中心”的主基因座（XCI）控制，这是一个顺式作用中心，它是必要且足以指导X染色体计数，选择​​和沉默的启动。我们的长期目标是了解每个步骤的分子基础。目前众所周知，Xist RNA是X灭活中心的非编码产品，“绘制”不活跃的X，并且需要启动该X的全球沉默。从上一个融资期开始的工作导致发现了两个新型的非编码RNA rna loci在X灭绝中心。 TSIX（一种对XIST的基因反义）抑制XIST表达，并指定了与低级基因间转录本相关的未来活性X. Xite。因此，X灭活中心的所有已知调节元素都会使得非编码RNA。拟议的研究将通过TSIX和XITE解剖作用机理。 Specifically, the proposed research will (1) determine how Xite and Tsix inhibit the spread of Xist RNA, (2) define the molecular basis of X-inactivation imprinting and choice, and (3) test if Xite is the Xce ("X-controlling element"), the long-elusive modifier of XCI allele ratios which has been implicated in unfavorable skewing of XCI in female carriers of X-linked 疾病。作为哺乳动物中极少数的反义基因座之一，TSIX是反义调节的范例。作为哺乳动物中仅有的两个已知功能基因间转录元件之一，Xite将提高对这一新出现的基因间现象的有限知识。从研究计划中获得的信息还将对人类遗传学，癌症和动物克隆以及染色体，染色质结构和转录调节的基本生物学产生重大影响。