Biochemical and structural investigation of UPF1 function in eukaryotic mRNA turnover pathways

UPF1 在真核 mRNA 周转途径中功能的生化和结构研究

• 批准号: 269535551
• 负责人: Professorin Dr. Sutapa Chakrabarti, Ph.D.
• 金额: --
• 依托单位: Chakrabarti Group - mRNA-Metabolism
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/269535551?language=en
• 关键词: Biochemical; structural; investigation; UPF1; function

This research proposal aims to dissect the role of the ATP-dependent RNA helicase UPF1 in cellular mRNA turnover pathways using a biochemical and structural (X-ray crystallography) approach. The degradation of mRNA is an important step in post-transcriptional gene regulation as it serves to regulate not only the level, but also the quality, of gene expression. As such, pathways of mRNA decay are implicated in several inflammatory and autoimmune disorders, as well as in genetic disorders that arise from aberrations in mRNA transcripts. Although there exist distinct pathways for the regulation mRNA levels (mRNA turnover) and mRNA quality control (mRNA surveillance), certain protein factors, such as UPF1, have been found to be involved in both kinds of degradation pathways. UPF1 was originally identified as a key component of the nonsense mediated mRNA decay (NMD) pathway, which is a surveillance pathway that degrades mRNA transcripts containing a premature stop codon. Subsequent studies showed that UPF1 can also act in conjunction with other RNA-binding proteins to regulate levels of specific target mRNAs. Although the mechanism and regulation of UPF1 in NMD is very well understood, little is known about its molecular mechanisms in mRNA turnover pathways. To this end, I will focus on two pathways of mRNA turnover that are mediated by UPF1: histone mRNA degradation and Staufen-mediated mRNA decay (SMD). Degradation of histone mRNA and SMD are mediated by the RNA binding proteins SLBP and Staufen respectively. These partner proteins recruit UPF1 in a translation termination-dependent manner to the 3'-UTR of the target mRNA. Localization of UPF1 to the 3'-UTR of the mRNA subsequently triggers degradation. Understanding how UPF1 is recruited by these RNA-binding proteins and dissecting its function in these pathways will elucidate its role in cellular mRNA turnover. This will enable us to generate a comprehensive model for UPF1 function (both in mRNA surveillance and mRNA turnover) and provide insight into the cross-talk between different mRNA degradation pathways in the eukaryotic cell. The proposed research will also be a distinct step towards viewing mRNA decay as a global phenomenon, rather than as individual linear pathways, and will enhance our knowledge of the regulation of disease-causing genes and of post-transcriptional gene regulation in general.

本研究计划旨在利用生化和结构（x射线晶体学）方法剖析atp依赖性RNA解旋酶UPF1在细胞mRNA转换途径中的作用。mRNA的降解是转录后基因调控的一个重要步骤，因为它不仅可以调节基因表达的水平，还可以调节基因表达的质量。因此，mRNA衰变的途径与几种炎症和自身免疫性疾病以及由mRNA转录物畸变引起的遗传疾病有关。尽管调控mRNA水平（mRNA周转）和mRNA质量控制（mRNA监控）存在不同的途径，但已经发现某些蛋白质因子，如UPF1，参与了这两种降解途径。UPF1最初被认为是无义介导的mRNA衰变（NMD）途径的关键组成部分，NMD是一种降解含有过早停止密码子的mRNA转录本的监视途径。随后的研究表明，UPF1还可以与其他rna结合蛋白联合作用，调节特定靶mrna的水平。虽然UPF1在NMD中的机制和调控已经被很好地理解，但其在mRNA转换途径中的分子机制却知之甚少。为此，我将重点关注UPF1介导的两种mRNA转换途径：组蛋白mRNA降解和staufen介导的mRNA衰变（SMD）。组蛋白mRNA和SMD的降解分别由RNA结合蛋白SLBP和Staufen介导。这些伙伴蛋白以翻译终止依赖的方式将UPF1招募到目标mRNA的3'-UTR上。UPF1定位到mRNA的3'-UTR随后触发降解。了解UPF1如何被这些rna结合蛋白募集，并剖析其在这些途径中的功能，将阐明其在细胞mRNA转换中的作用。这将使我们能够生成UPF1功能的综合模型（包括mRNA监测和mRNA周转），并深入了解真核细胞中不同mRNA降解途径之间的串扰。拟议的研究也将是将mRNA衰变视为一种全球现象而不是单个线性途径的独特步骤，并将增强我们对致病基因调控和转录后基因调控的总体认识。