Regulation of selenoprotein synthesis by SECIS-binding proteins

SECIS 结合蛋白对硒蛋白合成的调节

基本信息

批准号：
8309028
负责人：
DONNA M DRISCOLL
金额：
$ 34.15万
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：
2007
资助国家：
美国
起止时间：
2007-07-11 至 2015-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8309028
关键词：
3&apos Untranslated Regions Amino Acids Anabolism Antioxidants Arthritis Atherosclerosis Beryllium Binding Binding Proteins Binding Sites Cell Culture System Cells Cis-Acting Sequence Complex DNA Insertion Elements Development Dietary intake Ensure Eukaryotic Initiation Factors Fertility Foundations Funding Genetic Translation Goals Health Health Benefit Heart Diseases Heterogeneous-Nuclear Ribonucleoprotein K Human IS Elements Immunity Lead Link Malignant Neoplasms Mammalian Cell Maps Mediating Messenger RNA Micronutrients Modeling Molecular Molecular Profiling Outcome Pathway interactions Play Proteins RNA Reading Regulation Regulatory Pathway Regulon Reproduction Response Elements Role Selenium Selenocysteine Small Interfering RNA Structure Terminator Codon Testing Thyroid Gland Thyroid Hormones Trace Elements Trans-Activators Translational Regulation Translational Repression Translations Up-Regulation Virus Diseases Work base cancer prevention cohort disorder risk hormone metabolism in vitro Assay in vivo insight male mouse model novel therapeutics nucleolin research study response selenium deficiency selenoprotein stem

项目摘要

DESCRIPTION (provided by applicant): Selenium is an essential micronutrient that exerts many important health benefits. The element is incorporated into selenoproteins as selenocysteine (Sec). The mammalian selenoproteins perform critical functions in anti-oxidant defense, thyroid hormone metabolism, male reproduction, and development. Sec is encoded by UGA, which is normally read as a stop codon. The recoding of UGA as Sec requires the Sec Insertion Sequence (SECIS) element in the selenoprotein mRNA. Although much progress has been made in understanding the mechanism of Sec incorporation, much less is known about the regulation of this pathway. In selenium deficiency, certain selenoproteins that are critical for health and development are expressed while other nonessential selenoproteins are lost. The central hypothesis of our proposal is that this complex hierarchy of selenoprotein expression is maintained by the interplay between multiple trans-acting factors that bind selectively to different SECIS elements. We discovered two new SECIS-binding proteins, nucleolin and eukaryotic initiation factor 4a3 (eIF4a3) that play opposing roles in selectively modulating selenoprotein synthesis. We showed that eIF4a3 links selenium status with differential selenoprotein expression. EIF4a3 is upregulated in selenium-deficient cells where it selectively inhibits the incorporation of Sec into two selenoproteins that perform nonessential functions. In preliminary studies, we identified new targets of eIF4a3 and developed a model of the eIF4a3: SECIS interaction. We also present evidence that hnRNP K binds selectively to a SECIS from a nonessential selenoprotein but not from an essential selenoprotein. In this project, we will elucidate the roles of eIF4a3 and hnRNP K in regulating the expression of the selenoproteome using a combination of in vitro assays, cell culture systems, and mouse models. The successful completion of this project will provide critical insight into how mammalian cells prioritize the utilization of selenium during selenium insufficiency, an important health problem in many parts of the world. By identifying these regulatory pathways, our studies will provide a strong foundation for developing more specific and targeted approaches for modulating selenoprotein expression in vivo.

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。该元素以硒代半胱氨酸（Sec）的形式掺入硒蛋白中。哺乳动物硒蛋白在抗氧化防御、甲状腺激素代谢、雄性生殖和发育中发挥关键功能。 Sec 由 UGA 编码，通常被解读为终止密码子。将 UGA 重新编码为 Sec 需要硒蛋白 mRNA 中的 Sec 插入序列 (SECIS) 元件。尽管在理解 Sec 掺入机制方面已经取得了很大进展，但对该途径的调控却知之甚少。在缺硒时，某些对健康和发育至关重要的硒蛋白会表达，而其他非必需的硒蛋白则会丢失。我们提议的中心假设是，这种复杂的硒蛋白表达层次是通过选择性结合不同 SECIS 元件的多个反式作用因子之间的相互作用来维持的。我们发现了两种新的 SECIS 结合蛋白：核仁素和真核起始因子 4a3 (eIF4a3)，它们在选择性调节硒蛋白合成中发挥相反的作用。我们发现 eIF4a3 将硒状态与差异性硒蛋白表达联系起来。 EIF4a3 在缺硒细胞中上调，选择性抑制 Sec 掺入两种执行非必需功能的硒蛋白。在初步研究中，我们确定了 eIF4a3 的新靶点，并开发了 eIF4a3：SECIS 相互作用的模型。我们还提供了证据表明 hnRNP K 选择性地结合非必需硒蛋白的 SECIS，但不结合必需硒蛋白。在这个项目中，我们将结合体外测定、细胞培养系统和小鼠模型来阐明 eIF4a3 和 hnRNP K 在调节硒蛋白质组表达中的作用。该项目的成功完成将为了解哺乳动物细胞在硒缺乏期间如何优先利用硒提供重要的见解，硒缺乏是世界许多地区的一个重要健康问题。通过确定这些调控途径，我们的研究将为开发更具体和更有针对性的体内调节硒蛋白表达的方法奠定坚实的基础。