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细胞都含有相同的 DNA，但在发育过程中和不同组织中，细胞行为存在巨大差异。这些差异是通过基因表达的调节来实现的，即基因的 DNA 复制为 mRNA（转录）的过程，并且 mRNA 用作模板来制造编码的蛋白质（翻译）。细胞内产生的蛋白质网络决定了其功能。控制在正确的时间、正确的地点产生正确的蛋白质对于细胞发挥其功能并快速响应环境变化至关重要。这种调节的中心枢纽是 CCR4-NOT 蛋白复合物。 CCR4-NOT 可全局诱导 mRNA 降解，并通过靶向招募特定 mRNA 来诱导 mRNA 降解，并具有检测翻译延伸阶段核糖体暂停和调节蛋白质复合物共翻译组装的附加功能。 microRNA (miRNA) 是生物学和医学上重要的小 RNA 分子家族，通过与 mRNA 3' 非翻译区 (UTR) 中的序列特异性位点结合并直接招募 CCR4-NOT 来诱导 mRNA 降解和翻译抑制。此外，我们还发现肝脏特异性 miR-122 在促进丙型肝炎病毒 (HCV) 复制方面具有不寻常的作用。 CCR4-NOT 还促进 HCV 复制，同时我们已经证明蛋白质 eIF4A2 和 DDX6 直接被 CCR4-NOT 招募并参与细胞靶标和 HCV 的 miRNA 调节。目前尚不清楚 CCR4-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。这将在本提案中确定。内质网（ER）是真核细胞内的膜网络，在其中合成分泌蛋白和膜蛋白。编码这些蛋白质的 mRNA 被引导至发生翻译的内质网。我们最近发现 CCR4-NOT 特异性调节核糖体在 ER 靶向 mRNA 上的暂停，并且 ER 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 CCR4-NOT 对 HCV 的调节是否发生在该位置。在本提案中，我们将使用最先进的方法来确定 CCR4-NOT 如何控制整个细胞中蛋白质、mRNA 和 miRNA 的水平和位置。随后将详细探讨 CCR4-NOT 和 miRNA 调节 ER 和细胞质中的细胞和病毒靶标的机制。这项研究将对 CCR4-NOT 和 miRNA 对整个细胞和详细分子水平的影响提供前所未有的全球概述。这将为从根本上理解基因表达的控制做出重要贡献，同时也提供了操纵 mRNA 代谢的新途径，与新兴的 RNA 治疗领域具有相当大的相关性。