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）：硒是具有许多重要健康益处的必不可少的微量营养素。该元素被掺入亚硒蛋白中为硒代半胱氨酸（SEC）。哺乳动物硒蛋白在抗氧化剂防御，甲状腺激素代谢，男性繁殖和发育中发挥关键作用。 SEC由UGA编码，UGA通常将其读为终止密码子。 sec的重新编码需要硒蛋白mRNA中的SEC插入序列（SECIS）元件。尽管在理解SEC掺入机理方面取得了很多进展，但对该途径的调节知之甚少。在硒缺乏症中，某些对健康和发育至关重要的硒蛋白会在丢失其他非必需的硒蛋白时表达。我们建议的中心假设是，这种复杂的硒蛋白表达的复杂层次结构是通过选择性地与不同SECIS元素结合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，核醇蛋白和真核引发因子4A3（EIF4A3），它们在选择性调节硒蛋白合成中起着相反的作用。我们表明EIF4A3将硒状态与差异硒蛋白的表达联系起来。 EIF4A3在缺陷型细胞中被上调，在这些细胞中，它有选择地抑制将SEC掺入两种执行非必需功能的硒蛋白中。在初步研究中，我们确定了EIF4A3的新目标，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从非必需的硒蛋白中选择性结合，而不是基本硒蛋白的secis。在这个项目中，我们将使用体外测定，细胞培养系统和小鼠模型的组合来阐明EIF4A3和HNRNP K在调节硒蛋白蛋白体表达中的作用。该项目的成功完成将为您提供有关哺乳动物细胞在硒不足期间优先使用硒的优先级的批判性见解，这是世界许多地方的重要健康问题。通过识别这些调节途径，我们的研究将为开发更具体和有针对性的方法来调节体内的硒蛋白表达。