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

• 批准号: 8307411
• 负责人: DONNA M DRISCOLL
• 金额: $ 33.81万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8307411
• 关键词: 3' 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

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）：硒是一种必需的微量营养素，具有许多重要的健康益处。硒的营养需求可能是由于其在硒蛋白中的功能，硒蛋白含有硒代半胱氨酸（Sec）形式的元素，第21位氨基酸。哺乳动物硒蛋白在甲状腺激素代谢、抗氧化防御炎症和发育中起着关键作用。该提案的目标是了解硒蛋白合成的机制，并确定控制这一过程的效率的决定因素。将Sec掺入生长的多肽链需要翻译重编码事件，其中UGA终止密码子被读取为Sec。在真核生物中，将UGA重新编码为Sec依赖于硒蛋白mRNA的3'非翻译区中的Sec插入序列（SECIS）。SECIS与SECIS结合蛋白2（SBP 2）和核糖体蛋白L30相互作用，它们在重编码机制中起关键作用。我们在SBP 2中定义了一个新的二分RNA结合结构域，并表明该结构域中天然存在的与人类甲状腺功能减退相关的点突变改变了蛋白质的SECIS结合活性，并选择性地影响硒蛋白亚群的表达，包括参与甲状腺激素代谢的硒蛋白亚群。多条证据支持L30参与UGA重编码的假设，但这种核糖体蛋白如何在Sec掺入中发挥作用尚不清楚。我们的研究表明，有一个动态的交换SBP 2和L30上的SECIS和这两种蛋白质的行动顺序在UGA重新编码。这种逐步组装机制可以通过防止非生产性相互作用和协调一系列特定的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SBP 2：SECIS相互作用的分子基础; 2）测试的假设，SBP 2决定硒蛋白质组在体外和体内的表达;和3）阐明在哺乳动物细胞中硒蛋白合成L30的功能。在这个项目中产生的信息和分子工具将提供一个强大的基础，为未来的研究，在人类硒蛋白活性的缺陷，基因突变或多态性的基因编码的Sec掺入途径的组成部分。 公共卫生相关性：硒是饮食中的一种必需矿物质，对人类健康至关重要。硒的低膳食摄入，发生在世界许多地区，与疾病的风险增加，包括甲状腺问题，心脏病，炎症，关节炎，病毒感染和癌症。该项目的目标是了解硒是如何被纳入一个小而重要的蛋白质组中的，这些蛋白质在细胞中起着关键作用，并可能负责这种必需微量元素的有益作用。)