The role of the CCR4-NOT complex and mRNA regulatory elements in determining protein synthesis, destination and complex formation.

CCR4-NOT 复合物和 mRNA 调控元件在确定蛋白质合成、目的地和复合物形成中的作用。

• 批准号: BB/W01713X/1
• 负责人: Catherine Jopling
• 金额: $ 52.55万
• 依托单位: University of Nottingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FW01713X%2F1
• 关键词: role; CCR4; complex; mRNA; regulatory

While nearly all cells in an organism contain identical DNA, enormous differences in the behaviour of cells occur over the course of development and in different tissues. These differences are achieved by the regulation of gene expression, the process by which the DNA of a gene is copied to mRNA (transcription), and the mRNA is used as a template to make the encoded protein (translation). The network of proteins produced within a cell then dictates its function. Control of the production of the correct proteins in the right place at the right time is crucial in allowing cells to carry out their function and to respond rapidly to changes in environment. A central hub in this regulation is the CCR4-NOT protein complex. CCR4-NOT induces mRNA degradation, both globally and through targeted recruitment to specific mRNAs, and has additional functions in detecting ribosome pausing during the elongation stage of translation and modulating cotranslational assembly of protein complexes. microRNAs (miRNA) are a biologically and medically important family of small RNA molecules that induce mRNA degradation and translation repression by binding to sequence-specific sites in the 3'untranslated region (UTR) of mRNAs and directly recruiting CCR4-NOT. In addition, we have shown that liver-specific miR-122 has an unusual role in promoting hepatitis C virus (HCV) replication. CCR4-NOT also promotes HCV replication, while we have shown that the proteins eIF4A2 and DDX6 are directly recruited by CCR4-NOT and involved in miRNA regulation of both cellular targets and HCV. It remains unclear how CCR4-NOT integrates signals from miRNAs and ribosome pausing to control the production, location and assembly of proteins. This will be determined in this proposal.The endoplasmic reticulum (ER) is a network of membranes within eukaryotic cells where secreted and membrane proteins are synthesised. mRNAs that encode these proteins are directed to the ER where translation occurs. We have recently found that CCR4-NOT specifically regulates ribosome pausing on ER-targeted mRNAs, and that there are differences in miRNA repression at the ER and in the cytoplasm. HCV replication occurs in a membranous web derived from the ER, but it is not known whether miR-122 or CCR4-NOT regulation of HCV occurs in this location. In this proposal, we will use state-of-the-art approaches to determine how CCR4-NOT controls the level and location of proteins, mRNAs and miRNAs throughout the cell. This will be followed by detailed interrogation of the mechanisms by which CCR4-NOT and miRNAs regulate cellular and viral targets in the ER and cytoplasm. This study will provide an unprecedented global overview of the effects of CCR4-NOT and miRNAs on the whole cell and on a detailed molecular level. This will make an important contribution to the fundamental understanding the control of gene expression, while also providing new avenues to manipulate mRNA metabolism with considerable relevance to the emerging field of RNA therapeutics.

虽然生物体中几乎所有的细胞都含有相同的DNA，但在发育过程中和不同组织中，细胞的行为存在巨大差异。这些差异是通过基因表达的调节来实现的，基因的DNA被复制到mRNA（转录）的过程，mRNA被用作模板来产生编码的蛋白质（翻译）。细胞内产生的蛋白质网络决定了它的功能。在正确的时间和正确的地点控制正确的蛋白质的产生对于允许细胞执行其功能并对环境变化做出快速反应至关重要。这个调控的中心枢纽是CCR 4-NOT蛋白复合物。CCR 4-NOT诱导mRNA降解，无论是全局还是通过靶向募集到特定mRNA，并且在翻译的延伸阶段检测核糖体暂停和调节蛋白质复合物的共翻译组装中具有额外的功能。microRNA（miRNA）是一类具有重要生物学和医学意义的小RNA分子家族，通过与mRNA 3 '非翻译区（UTR）序列特异性位点结合，直接募集CCR 4-NOT，从而诱导mRNA降解和翻译抑制。此外，我们已经证明肝脏特异性miR-122在促进丙型肝炎病毒（HCV）复制方面具有不寻常的作用。CCR 4-NOT也促进HCV复制，而我们已经表明，蛋白eIF 4A 2和DDX 6直接由CCR 4-NOT招募，并参与细胞靶点和HCV的miRNA调控。目前还不清楚CCR 4-NOT如何整合来自miRNA和核糖体暂停的信号来控制蛋白质的产生、定位和组装。内质网（ER）是真核细胞内的膜网络，分泌蛋白和膜蛋白在此合成。编码这些蛋白质的mRNA被定向到ER，在那里发生翻译。我们最近发现，CCR 4-NOT特异性调节内质网靶向mRNA的核糖体停顿，并且内质网和细胞质中的miRNA抑制存在差异。HCV复制发生在源自ER的膜网中，但尚不清楚miR-122或CCR 4-NOT对HCV的调节是否发生在该位置。在这个提议中，我们将使用最先进的方法来确定CCR 4-NOT如何控制整个细胞中蛋白质，mRNA和miRNA的水平和位置。随后将详细询问CCR 4-NOT和miRNA调节ER和细胞质中的细胞和病毒靶标的机制。这项研究将提供CCR 4-NOT和miRNA对整个细胞和详细分子水平影响的前所未有的全球概述。这将对基因表达控制的基本理解做出重要贡献，同时也为操纵mRNA代谢提供了新的途径，与新兴的RNA治疗领域具有相当大的相关性。