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.

尽管生物体中几乎所有细胞都包含相同的DNA，但在发育和不同组织中，细胞行为的巨大差异发生。这些差异是通过基因表达的调节来实现的，基因的DNA复制到mRNA（转录），并将mRNA用作制造编码蛋白（翻译）的模板。然后在细胞内产生的蛋白质网络决定其功能。在正确的时间控制正确位置的正确蛋白质的生产对于允许细胞执行其功能并迅速响应环境变化至关重要。该调节中的中心枢纽是CCR4-NOT蛋白复合物。 CCR4-不诱导MRNA降解，无论是在全球范围内还是通过靶向募集到特定的mRNA中，并且在转化的延长阶段和调节蛋白质复合物的共转移组装时具有其他功能。 MicroRNA（miRNA）是一种生物学和医学上重要的小RNA分子家族，通过与mRNA的3'untranslated区域（UTR）中的序列特异性位点结合并直接募集CCR4-NOT，诱导mRNA降解和翻译抑制。此外，我们已经表明，肝脏特异性miR-122在促进丙型肝炎病毒（HCV）复制中具有非同寻常的作用。 CCR4-NOT还促进了HCV复制，而我们已经证明蛋白质EIF4A2和DDX6直接被CCR4-NOT募集，并参与了细胞靶标和HCV的miRNA调节。尚不清楚CCR4如何整合来自miRNA和核糖体的信号，以控制蛋白质的生产，位置和组装。这将在此提案中确定。内质网（ER）是在真核细胞内的膜网络，其中分泌和膜蛋白是合成的。编码这些蛋白质的mRNA针对发生翻译的ER。我们最近发现，CCR4-不专门调节在靶向ER的mRNA上暂停的核糖体，并且在ER和细胞质中，miRNA抑制存在差异。 HCV复制发生在源自ER的膜网中，但尚不知道MiR-122或CCR4是否在此位置发生HCV的调节。在此提案中，我们将使用最先进的方法来确定CCR4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CCR4-NOT和miRNA调节ER和细胞质中细胞和病毒靶标的机制。这项研究将提供前所未有的全球概述，概述CCR4-NOT和miRNA对整个细胞以及详细的分子水平的影响。这将为理解基因表达的控制的基本理解做出重要贡献，同时还提供了与RNA Therapeutics的新兴领域相关的新途径来操纵mRNA代谢。