Mechanisms of Circadian Clock Control of mRNA Translation

mRNA 翻译的昼夜节律时钟控制机制

• 批准号: 10152622
• 负责人: Deborah Bell-Pedersen
• 金额: $ 70.79万
• 依托单位: TEXAS A&M UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-01 至 2023-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10152622
• 关键词: Affect; Behavior; Cardiovascular Diseases; Cells; Data; Defect; Disease; Eukaryotic Initiation Factors; Functional disorder; Gene Expression; Gene Proteins; Genetic Transcription; Genetic Translation; Heart Diseases; Human; Instruction; Lead; Link; Malignant Neoplasms; Messenger RNA; Metabolic syndrome; Modification; Neurospora crassa; Organism; Peptide Elongation Factor 2; Periodicity; Pharmaceutical Preparations; Phosphorylation; Physiology; Proteins; Regulation; Research; Ribosomal Proteins; Ribosomes; Role; Signal Transduction; Sleep Disorders; Specificity; Testing; Time; Toxic effect; Translations; cell type; circadian; circadian pacemaker; drug metabolism; insight; novel strategies; protein expression; ribosome profiling; tool; transcriptome sequencing; translation factor

Project Summary The circadian clock is an evolutionarily conserved time-keeping mechanism that, through the regulation of rhythmic gene expression, coordinates the physiology of an organism with daily environmental cycles. Because nearly all aspects of human physiology and behavior are linked to the clock, clock dysfunction is associated with a wide range of diseases, including sleep disorders, cardiovascular disease, metabolic syndrome, and cancer. In addition, the clock controls the efficacy and toxicity of many drugs. Therefore, identifying what genes and proteins are regulated by the clock, and determining the mechanisms for this regulation, are key to understanding clock-associated diseases and rhythmic drug metabolism. While the primary focus of research on circadian control of gene expression has been at the transcriptional level, recent evidence supports a role for the clock in regulating posttranscriptional mechanisms. How the clock regulates mRNA translation is poorly understood. We found that the Neurospora crassa circadian clock controls the phosphorylation of two highly conserved central regulators of mRNA translation, eukaryotic elongation factor 2 (eEF2), and eukaryotic initiation factor 2α (eIF2α). Using high throughput RNA-seq and ribosome profiling in wild type cells, and cells that are defective in rhythmic activity of the translation factors, we found that clock regulation of translation factor activity affects translation of specific mRNAs, rather than acting globally to regulate translation of all mRNAs. During the next 5 years, we will leverage our expertise and tools to determine the mechanisms for this specificity. In an exciting breakthrough, we found that the clock controls the composition of cytoplasmic ribosomes, whereby certain ribosomal proteins cycle in abundance in ribosomes. These data challenge the paradigm that all cytoplasmic ribosomes are the same, and instead suggest the existence of heterologous ribosomes with distinct functions. We will capitalize on these findings to test the hypothesis that changes in ribosome protein composition, modification, and/or interactions with accessory proteins occur temporally under control of the clock. Elucidating the clock-regulated ribosome modification mechanism may also lead to insights into unexpected ways that signals other than the clock might postranscriptionally regulate protein expression.

项目概要 生物钟是一种进化上保守的计时机制，通过调节 有节奏的基因表达，协调生物体的生理学与日常环境周期。 由于人类生理和行为的几乎所有方面都与时钟有关，因此时钟功能障碍是 与多种疾病有关，包括睡眠障碍、心血管疾病、代谢疾病 此外，时钟控制着许多药物的功效和毒性。 确定哪些基因和蛋白质受时钟调节，并确定其机制 调节，是时钟相关疾病和了解节律药物代谢的关键。 虽然基因表达的昼夜节律控制研究的主要焦点是转录 在水平上，最近的证据支持时钟在调节转录后机制中的作用。 我们对粗糙脉孢菌生物钟的调节机制知之甚少。 控制 mRNA 翻译的两个高度保守的中央调节因子的磷酸化，真核生物 使用高通量 RNA-seq 和延伸因子 2 (eEF2) 和真核起始因子 2α (eIF2α)。 我们对野生型细胞和翻译因子节律活性有缺陷的细胞进行核糖体分析 发现翻译因子活性的时钟调节影响特定 mRNA 的翻译，而不是作用 未来 5 年，我们将利用我们的专业知识和工具在全球范围内监管所有 mRNA 的翻译。 为了确定这种特异性的机制，我们取得了令人兴奋的突破，发现时钟控制。 细胞质核糖体的组成，某些核糖体蛋白在其中大量循环 这些数据挑战了所有细胞质核糖体都是相同的范式，而是 表明存在具有不同功能的异源核糖体。我们将利用这些发现来进行研究。 检验核糖体蛋白质组成、修饰和/或相互作用发生变化的假设 辅助蛋白在时钟的控制下暂时发生。阐明时钟调节的核糖体。 修改机制还可能导致对时钟以外的信号可能出现的意想不到的方式的见解 转录后调节的蛋白质表达。