Regulation of Messenger RNA Turnover in Mammalian Cells

项目说明 我实验室的研究重点是阐明原理和调节机制 控制信使RNA在哺乳动物细胞中的周转。信使核糖核酸的周转在调节中起着至关重要的作用 通过控制mRNA的稳定性和质量，在全球和个体水平上进行基因表达 MRNAs。在哺乳动物细胞中，所有主要的信使核糖核酸衰变模式都是由去烯基化(即， 从mRNAs的3‘端去除聚(A)尾)，这是一种涉及两个连续的 动力学阶段。尽管以前的研究清楚地描述了机械性步骤和 参与mRNA衰变途径的因素，对去烯基化的影响知之甚少 及其在转录组水平上对mRNA周转的调控。尤其缺乏的是对 整个mRNA组的稳定性的协调变化如何有助于规划或 当哺乳动物细胞对细胞内或细胞外刺激做出反应时，转录组的重新编程。在 在细胞质中，mRNAs以mRNA-蛋白质复合体(MRNPs)的形式发挥功能。MRNPs是 高度动态的实体，通过其蛋白质成分的快速交换而不断重塑， 决定着单个mRNA在其生命周期的每一步的命运。任何不适当的mRNP改建 Complex有可能扰乱其对下游活动的适当参与。目前，一个令人兴奋的问题 在RNA生物学中未被开发的研究领域是mRNPs在个体、群体和 在mRNA去烯化和衰变过程中的全球水平。 我们目前的建议集中在哺乳动物RNA生物学的三个看似完全不同的方面 它们通过调节全球mrna来塑造哺乳动物转录组的潜力相互联系。 周转和mRNP重塑。它们是：1)选择性3‘末端加工和聚腺苷酸化(APA)， 它产生具有不同3‘非翻译区的mRNA异构体；2)mRNA N6-甲基腺苷(M6A) 修饰，产生具有不同代谢命运的mRNA异构体；以及3)磷酸化 辅助去烯化因子，改变mRNA去烯化和衰变。在过去几年中，我们 我在这三个方面取得了几项重要发现，这些发现有助于为 建议在这一应用中进行研究。我们还调整和进一步开发了关键的分析 阐明靶向过程对整个过程中信使核糖核酸周转的影响的方法 转录组及其去烯化通过mRNP影响mRNA稳定性的机制 改建。成功完成拟议的研究将为阐明 在转录组水平上对mRNA稳定性和mRNP重塑的信号依赖调节，以及 这些结果将大大扩大对真核基因信使核糖核酸基本原理的理解。 营业额。

Project Description Research in my laboratory focuses on elucidating the principles and regulatory mechanisms that govern messenger RNA turnover in mammalian cells. mRNA turnover plays an essential role in regulating gene expression via control of mRNA stability and quality, both globally and at the level of individual mRNAs. In mammalian cells, all major modes of mRNA decay are triggered by deadenylation (i.e., the removal of the poly(A) tails from the 3' end of mRNAs), a rate-limiting process involving two consecutive kinetic phases. Although previous studies provided a clear picture of the mechanistic steps and participating factors of mRNA decay pathways, relatively little is known about the impact of deadenylation and its modulation on mRNA turnover at the transcriptome level. Particularly lacking is an understanding of how coordinated changes in stability for whole groups of mRNAs contribute to programming or reprogramming of the transcriptome when mammalian cells respond to intra- or extra-cellular stimuli. In the cytoplasm, mRNAs fulfill their functions in the form of mRNA-protein complexes (mRNPs). mRNPs are highly dynamic entities, being continuously remodeled by rapid exchanges of their protein constituents, dictating individual mRNAs' fates at each step of their lifespan. Any inappropriate remodeling of an mRNP complex has the potential to disrupt its proper engagement in downstream events. Currently, one exciting and underexplored area of research in RNA biology is the remodeling of mRNPs at individual, group, and global levels during the process of mRNA deadenylation and decay. Our present proposal focuses on three seemingly disparate aspects of mammalian RNA biology that are linked by their potential to shape the mammalian transcriptome through modulating global mRNA turnover and mRNP remodeling. These are: 1) Alternative 3' end processing and polyadenylation (APA), which generates mRNA isoforms with distinct 3' untranslated regions; 2) mRNA N6-methyladenosine (m6A) modification, which creates mRNA isoforms with different metabolic fate; and 3) Phosphorylation of ancillary deadenylation factors, which alters mRNA deadenylation and decay. In the past few years, we have made several key findings regarding these three areas that have helped lay the groundwork for the proposed studies in this application. We have also adapted and further developed key analytical approaches to elucidating the impacts of the targeted processes on mRNA turnover across the transcriptome and the mechanisms by which deadenylation impacts mRNA stability through mRNP remodeling. Successful completion of the proposed studies will offer a new framework for elucidating the signal-dependent regulation of mRNA stability and mRNP remodeling at the transcriptome level, and the results will significantly expand understanding of the fundamental principles governing eukaryotic mRNA turnover.