Roles of Non-coding RNA, roX, in Global Chromatin Organization

非编码 RNA roX 在全球染色质组织中的作用

• 批准号: 0818464
• 负责人: Yongkyu Park
• 金额: $ 48万
• 依托单位: Rutgers, The State University of New Jersey-RBHS-New Jersey Med
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0818464&HistoricalAwards=false
• 关键词: Roles; Non; coding; RNA; roX

Intellectual merit: Recent analyses of the genomes of various higher eukaryotic animals such as mice and humans have shown that an unexpectedly large fraction of transcripts do not encode proteins but rather specify functional RNAs. A growing body of evidence suggests that these non-coding transcripts are involved in a variety of regulatory mechanisms including chromatin organization, and that disruption of these processes can have drastic consequences for the organism. This project focuses on the role of the roX RNAs in dosage compensation in fruit flies, where males have a single X chromosome and females have two X chromosomes, similar to the XX and XY complement present in humans and other mammals. In flies, dosage compensation entails up-regulating the expression of hundreds of unrelated genes present on the X chromosome in order to equalize the quantities of the gene products between the sexes. Thus, it is an excellent model system to understand several aspects of eukaryotic gene regulation by non-coding RNA. The central player in dosage compensation is the MSL (Male Specific Lethal) complex, which includes the non-coding roX1 and roX2 RNAs and acts exclusively on the male X chromosome. A key development in the field was the discovery that the action of the MSL complex on the X chromosme is mediated by histone modification (specifically, acetylation of lysine 16 in histone H4). The goal of the present research is to characterize the molecular mechanism through which the conserved functional domains of the roX RNAs regulate the enzymatic activity of the MSL complex on the male X chromosome to achieve two-fold up-regulation of X-linked genes. By revealing the relationship between the structure and function of the roX RNAs, the project will define new aspects of RNA-protein interactions and their relevance in the context of chromatin remodeling complexes. Importantly, X-chromosome inactivation in mammals is also dependent on a complex that includes a non-coding RNA known as Xist. Although the Xist complex induces gene silencing on the X chromosome, in contrast to the up-regulation promoted by the MSL complex in fruit flies, a shared feature is the initiation of chromatin remodeling accompanied by spreading in cis from a non-coding RNA binding site. Beyond the involvement of epigenetic changes induced by global histone modification, the roles of non-coding RNAs in these processes are not well understood. Thus, the information obtained from studies of roX RNA will lead to enhanced understanding of X-chromosome inactivation in mammals and has the potential to advance general understanding of non-coding RNA-dependent gene regulation in eukaryotes.Broader impacts: Participants in a minority summer student research program for high school and undergraduate students will be included in the research activities in order to teach them principles and techniques of basic science. To disseminate information about RNA analysis tools including RNA structure prediction, alignmentsand searches, an internet-based facility for public users (http://bioinformatics.njit.edu/rna) will be continuously updated with non-coding RNA (roX) data generated through the project. To ensure open scientific communication, all data, protocols, constructs and transgenic flies developed through the project will be shared with other laboratories and institutions. Members of the research team will participate in multi- and interdisciplinary conferences and present research results obtained from the project. A long-term goal is for the contributions of the research to the field of chromatin organization to be integrated into basic education resources such as textbooks for graduate and undergraduate students.

学术价值：最近对小鼠和人类等各种高等真核动物的基因组进行的分析表明，出人意料的是，大部分转录本并不编码蛋白质，而是特异功能性 RNA。越来越多的证据表明，这些非编码转录本参与了包括染色质组织在内的多种调节机制，而这些过程的破坏可能会对生物体产生严重的后果。该项目重点研究 roX RNA 在果蝇剂量补偿中的作用，其中雄性有一条 X 染色体，雌性有两条 X 染色体，类似于人类和其他哺乳动物中存在的 XX 和 XY 补体。 在果蝇中，剂量补偿需要上调 X 染色体上数百个不相关基因的表达，以平衡两性之间基因产物的数量。 因此，它是了解非编码 RNA 真核基因调控的几个方面的优秀模型系统。剂量补偿的核心角色是 MSL（男性特异性致死）复合物，它包括非编码 roX1 和 roX2 RNA，专门作用于男性 X 染色体。该领域的一个关键进展是发现 MSL 复合物对 X 染色体的作用是通过组蛋白修饰（特别是组蛋白 H4 中的赖氨酸 16 的乙酰化）介导的。本研究的目标是表征roX RNA的保守功能域调节男性X染色体上MSL复合物的酶活性以实现X连锁基因两倍上调的分子机制。通过揭示 roX RNA 的结构和功能之间的关系，该项目将定义 RNA-蛋白质相互作用的新方面及其在染色质重塑复合物背景下的相关性。重要的是，哺乳动物中 X 染色体失活还依赖于一种复合物，该复合物包含一种称为 Xist 的非编码 RNA。 虽然 Xist 复合物诱导 X 染色体上的基因沉默，但与果蝇中 MSL 复合物促进的上调相反，共同的特征是染色质重塑的启动，伴随着从非编码 RNA 结合位点顺式扩展。除了整体组蛋白修饰引起的表观遗传变化之外，非编码 RNA 在这些过程中的作用尚不清楚。因此，从 roX RNA 研究中获得的信息将有助于增强对哺乳动物 X 染色体失活的理解，并有可能促进对真核生物中非编码 RNA 依赖性基因调控的一般理解。 更广泛的影响：针对高中生和本科生的少数暑期学生研究项目的参与者将被纳入研究活动，以便向他们传授基础科学的原理和技术。为了传播有关 RNA 分析工具（包括 RNA 结构预测、比对和搜索）的信息，面向公众用户的基于互联网的设施 (http://bioinformatics.njit.edu/rna) 将使用通过该项目生成的非编码 RNA (roX) 数据不断更新。为了确保开放的科学交流，通过该项目开发的所有数据、协议、结构和转基因果蝇将与其他实验室和机构共享。研究团队成员将参加多学科和跨学科的会议并展示从项目中获得的研究成果。 长期目标是将研究对染色质组织领域的贡献纳入研究生和本科生教科书等基础教育资源中。