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.

项目摘要 昼夜节律是一种进化保守的时间保存机制，通过调节 有节奏的基因表达，将生物体的生理学与每日环境周期进行协调。 因为人类生理和行为的几乎所有方面都与时钟相关，所以时钟功能障碍是 与多种疾病有关，包括睡眠障碍，心血管疾病，代谢 综合征和癌症。此外，时钟控制着许多药物的效率和毒性。所以， 确定哪些基因和蛋白质受时钟的调节，并确定为此的机制 调节是了解时钟相关疾病和节奏药物代谢的关键。 虽然研究对基因表达的昼夜节律控制的主要重点是转录 级别，最近的证据支持时钟在确定转录后机制中的作用。时钟如何 调节mRNA翻译知之甚少。我们发现Neurospora Crassa昼夜节律钟 控制两个高度保守的mRNA翻译中心调节剂的磷酸化，真核生物 伸长因子2（EEF2）和真核起始因子2α（EIF2α）。使用高吞吐量RNA-seq和 野生型细胞中的核糖体分析，以及在翻译因子的节奏活性中有缺陷的细胞，我们 发现翻译因子活动的时钟调节会影响特定mRNA的翻译，而不是作用 在全球范围内调节所有mRNA的翻译。在接下来的5年中，我们将利用我们的专业知识和工具 确定这种特异性的机制。在一个令人兴奋的突破中，我们发现时钟控制 细胞质核糖体的组成，其中某些核糖体蛋白在丰度中循环 核糖体。这些数据挑战了所有细胞质核糖体相同的范式，而是 建议存在具有不同功能的异源核糖体。我们将利用这些发现 测试核糖体蛋白组成，修饰和/或与/或相互作用的假设 辅助蛋白暂时发生在时钟的控制下。阐明时钟调节的核糖体 修改机制也可能导致对表明时钟以外的其他方式的意外方式的见解 文字上调节蛋白质表达。