Translational Recoding of UGA as Selenocysteine in Selenoprotein Synthesis

硒蛋白合成中 UGA 翻译重新编码为硒代半胱氨酸

基本信息

批准号：
8519998
负责人：
DONNA M DRISCOLL
金额：
$ 32.62万
依托单位：
CLEVELAND CLINIC LERNER COM-CWRU
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-08-01 至 2015-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8519998
关键词：
3&apos Untranslated Regions Active Sites Affect Affinity Amino Acids Antioxidants Arthritis Binding Binding Proteins Binding Sites Cells Charge Cis-Acting Sequence Complex DNA Insertion Elements Defect Development Diet Dietary intake Dissociation Elements Elongation Factor Endogenous Factors Enzymes Eukaryota Event Foundations Future Gene Mutation Genes Genetic Polymorphism Goals Health Health Benefit Heart Diseases Human Hypothyroidism IS Elements In Vitro Indium Infection Inflammation Knock-in Mouse Knockout Mice Knowledge Learning Link Malignant Neoplasms Mammalian Cell Maps Messenger RNA Micronutrients Minerals Modeling Molecular Mutagenesis Null Lymphocytes Nutritional Requirements Organism Oxidation-Reduction Pathway interactions Physiological Play Point Mutation Process Protein Binding Protein Biosynthesis Proteins RNA RNA Recognition Motif RNA-Binding Proteins Reading Recruitment Activity Research Ribosomal Proteins Ribosomes Role Selenium Selenocysteine Series Signal Transduction Site Specificity Structure Terminator Codon Testing Thyroid Gland Thyroid Hormones Tissues Trace Elements Trans-Activators Translations Vial device Virus Diseases Yeasts base disorder risk hormone metabolism in vivo mutant novel polypeptide prevent protein complex protein function public health relevance ribosomal protein L30 selenocysteine insertion sequence binding protein 2 selenoprotein stem tool

项目摘要

DESCRIPTION (provided by applicant): Selenium is an essential micronutrient that exerts many important health benefits. The nutritional requirement for selenium is likely due to its function in selenoproteins, which contain the element in the form of selenocysteine (Sec), the 21st amino acid. Mammalian selenoproteins perform critical functions in thyroid hormone metabolism, anti-oxidant defense inflammation, and development. The goal of this proposal is to understand the mechanism of selenoprotein synthesis and identify the determinants that control the efficiency of this process. The incorporation of Sec into the growing polypeptide chain requires a translational recoding event in which the UGA stop codon is read as Sec. In eukaryotes, the recoding of UGA as Sec depends on the Sec Insertion Sequence (SECIS) in the 3' untranslated region of the selenoprotein mRNA. The SECIS interacts with SECIS Binding Protein 2 (SBP2) and ribosomal protein L30, which play critical roles in the recoding mechanism. We defined a novel bipartite RNA- binding domain in SBP2 and showed that a naturally occurring point mutation in this domain, which is associated with hypothyroidism in humans, alters the SECIS-binding activity of the protein and selectively affects the expression of a subset of selenoproteins, including those involved in thyroid hormone metabolism. Multiple lines of evidence support the hypothesis that L30 is involved in UGA recoding but how this ribosomal protein functions in Sec incorporation is not known. Our studies suggest that there is a dynamic exchange of SBP2 and L30 on the SECIS and that the two proteins act sequentially during UGA recoding. Such a stepwise assembly mechanism may enhance the efficiency of selenoprotein synthesis by preventing nonproductive interactions and orchestrating a specific series of events. In this project, we propose to: 1) understand the molecular basis for the SBP2:SECIS interaction; 2) test the hypothesis that SBP2 dictates the expression of the selenoproteome in vitro and in vivo; and 3) elucidate the function of L30 in selenoprotein synthesis in mammalian cells. The information and molecular tools generated in this project will provide a strong foundation for future studies linking defects in selenoprotein activity in humans to genetic mutations or polymorphisms in genes that encode components of the Sec incorporation pathway. PUBLIC HEALTH RELEVANCE: Selenium, an essential mineral in the diet, is critical for human health. Low dietary intake of selenium, which occurs in many regions of the world, is associated with an increased risk of disease, including thyroid problems, heart disease, inflammation, arthritis, viral infection, and cancer. The goal of this project is to understand how selenium is incorporated into a small but important group of proteins, which play critical roles in the cell and are likely responsible for the beneficial effects of this essential trace element. )

描述（由申请人提供）：硒是具有许多重要健康益处的必不可少的微量营养素。硒的营养需求可能是由于其在硒蛋白中的功能，该蛋白质以硒代半胱氨酸（SEC）为元素，第21氨基酸的形式。哺乳动物硒蛋白在甲状腺激素代谢，抗氧化剂防御炎症和发育中发挥关键功能。该建议的目的是了解硒蛋白合成的机制，并确定控制该过程效率的决定因素。将SEC掺入不断增长的多肽链中需要一个翻译重新编码事件，其中UGA终止密码子被读为SEC。在真核生物中，uga作为SEC的重现取决于硒蛋白mRNA的3'未翻译区域中的SEC插入序列（SECIS）。 SECIS与SECIS结合蛋白2（SBP2）和核糖体蛋白L30相互作用，这些蛋白L30在重新编码机理中起关键作用。我们在SBP2中定义了一个新型的两分性RNA结合结构域，并表明该结构域中的天然存在点突变与人类的甲状腺功能减退有关，改变了蛋白质的secis结合活性，并选择性地影响硒蛋白蛋白亚集的表达，包括参与甲状腺激素代谢的人。多种证据支持了L30参与UGA重新编码的假设，但是该核糖体蛋白在SEC掺入中的功能尚不清楚。我们的研究表明，SECIS上有SBP2和L30的动态交换，并且两种蛋白质在UGA重新编码过程中依次起作用。这种逐步组装机制可以通过防止非生产性相互作用并策划一系列特定事件来提高硒蛋白合成的效率。在这个项目中，我们建议：1）了解SBP2：SECIS相互作用的分子基础； 2）检验了SBP2在体外和体内决定硒蛋白蛋白体的表达的假设； 3）阐明哺乳动物细胞中硒蛋白合成中L30的功能。该项目中产生的信息和分子工具将为将来的研究提供巨大的基础，将人类中硒蛋白活性与遗传突变或编码SEC掺入途径的基因的遗传突变或多态性联系在一起。公共卫生相关性：Selenium是饮食中必不可少的矿物质，对人类健康至关重要。在世界许多地区发生的硒饮食摄入量低，与疾病的风险增加有关，包括甲状腺问题，心脏病，炎症，关节炎，病毒感染和癌症。该项目的目的是了解如何将硒纳入一个小但重要的蛋白质群中，这些蛋白质在细胞中起着关键作用，并可能导致该基本痕量元素的有益作用。）