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: 10620952
• 负责人: Deborah Bell-Pedersen
• 金额: $ 74.93万
• 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 2028-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10620952
• 关键词: Amino Acids; Amino Acyl-tRNA Synthetases; Binding; Cell physiology; Cells; Cellular Metabolic Process; Charge; Circadian Rhythms; Defect; Disease; EIF-2alpha; Eukaryota; Genome; Health; Heart Diseases; Human; Malignant Neoplasms; Messenger RNA; Metabolic syndrome; Metabolism; Methionine; Methionine-tRNA Ligase; Modeling; Molecular Chaperones; Neurospora crassa; Periodicity; Pharmaceutical Preparations; Pharmacotherapy; Phosphorylation; Phosphotransferases; Probability; Production; Protein Biosynthesis; Proteins; Proteome; Regulation; Regulatory Pathway; Ribosomal Proteins; Ribosomes; Sleep Disorders; Terminator Codon; Testing; Time; Transfer RNA; Transfer RNA Aminoacylation; Translating; Translation Initiation; Translations; Work; circadian pacemaker; circadian regulation; drug metabolism; improved; insight; mRNA Translation; novel strategies; protein folding

Summary The circadian clock, critical to human health and drug metabolism, regulates rhythmic protein production and thus cell function and metabolism. Many proteins whose levels show robust circadian rhythms are produced from mRNAs that are not rhythmic. Using the model eukaryote Neurospora crassa, we found that up to half of this circadian regulation of protein levels is through clock control of the activities of a conserved regulator of translation initiation (eIF2α), and the protein composition of translating ribosomes. We also made the surprising observation that the circadian clock controls the probability that ribosomes will read through the normal stop codon to produce proteins with carboxy-terminal extensions and potentially new functions. In addition, we found that the clock regulates the levels of tRNA synthetases that charge tRNAs with the appropriate amino acids for translation, and thus are critical for accurate protein synthesis. Over the next 5 years, we will capitalize on these findings to test the exciting hypothesis that the circadian clock controls daily changes in translation fidelity and thus protein diversity beyond what is encoded for in the genome. We will determine if clock control of ribosome composition is necessary, and which specific ribosomal proteins are required, for rhythmic stop codon readthrough. In addition, we will test if circadian clock control of binding of the co-chaperone Zuotin to ribosomes regulates daily rhythms in protein folding. We will determine the impact of circadian rhythms in methionyl-tRNA synthetase (MetRS) levels, and rhythms in the activities of kinases that phosphorylate MetRS, on three different MetRS regulatory pathways. These include translation initiation through charging of the initiator methionyl tRNA, translation elongation through charging of elongator methionyl tRNA, and misincorporation of methionine during protein synthesis through the mischarging of non-cognate tRNA. This work will significantly impact our understanding of both how a cell is different at different times of the day, and how the proteome can be more diverse than what one would predict from the genome sequence.

概括 昼夜节律对人类健康和药物代谢至关重要，调节节奏蛋白的产生 因此细胞功能和代谢。许多蛋白质的水平显示出强大的昼夜节律 来自不是有节奏的mRNA。使用型真核生物Neurospora crassa，我们发现多达一半 这种对蛋白质水平的昼夜节律调节是通过对成本调节剂的活动的时钟控制 翻译起始（EIF2α）和翻译核糖体的蛋白质组成。我们也感到惊讶 观察昼夜节律控制核糖体将通过正常停止读取的概率 用羧基末端扩展和潜在的新功能产生蛋白质的密码子。此外，我们发现 时钟调节与适当的氨基酸为TRNA的TRNA合成酶的水平 翻译，因此对于准确的蛋白质合成至关重要。在接下来的5年中，我们将利用这些 研究结果是为了检验昼夜节律的令人兴奋的假设，控制了翻译忠诚度和 这种蛋白质多样性超出了基因组中编码的蛋白质多样性。我们将确定核糖体的时钟控制 有节奏的终止密码子需要组成，并且需要哪种特定的核糖体蛋白 读取。此外，我们还将测试昼夜节律对伴侣蛋白与核糖体的结合的时钟控制 调节蛋白质折叠的每日节奏。我们将确定昼夜节律对甲基龙的影响 合成酶（METRS）水平和节奏在三种不同的激酶的活性中 METRS监管途径。这些包括通过启动甲基tRNA充电的翻译启动， 通过伸长蛋白蛋白基tRNA的充电和蛋氨酸的失调，通过伸长伸长。 蛋白质合成，通过非认知tRNA的错误充电。这项工作将极大地影响我们的 了解细胞在一天的不同时间之间的不同之处，以及蛋白质组如何更多 潜水员比从基因组序列中预测的。