The effects of dietary selenium on translational control of protein synthesis

膳食硒对蛋白质合成翻译控制的影响

• 批准号: 9897535
• 负责人: MICHAEL T HOWARD
• 金额: $ 30.91万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2023-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9897535
• 关键词: 3' Untranslated Regions; Address; Affect; Affinity; Amino Acids; Animal Model; Apoptosis; Biochemical; Biological; Cells; Cellular Stress; Codon Nucleotides; Complex; DNA Insertion Elements; Data; Dietary Selenium; Disease; Gene Expression; Genes; Genetic Code; Genetically Modified Animals; Goals; Health; High-Throughput Nucleotide Sequencing; Human; IS Elements; In Vitro; Iodide Peroxidase; Knowledge; Laboratories; Lead; Link; Location; Male Infertility; Malignant Neoplasms; Mammals; Mass Spectrum Analysis; Messenger RNA; Methods; Modeling; Molecular; Mus; Myopathy; Neurodegenerative Disorders; Peptides; Physiological; Play; Process; Production; Protein Biosynthesis; Proteins; RNA; Reaction; Regulation; Ribonucleoproteins; Ribosomes; Role; Selenium; Selenocysteine; Specific qualifier value; Staging; Structure; Techniques; Technology; Testing; Thyroid Hormones; Tissues; To specify; Trans-Activators; Translating; Translation Process; Translations; Untranslated RNA; Virus Diseases; deep sequencing; endoplasmic reticulum stress; environmental change; experimental study; glutathione peroxidase; improved; in vivo; insight; interest; novel; response; selenium deficiency; selenocysteine-tRNA; selenoprotein; stem; thioredoxin reductase

Selenocysteine is incorporated into selenoproteins during translation by an unconventional mechanism involving a dedicated Sec-tRNA that decodes UGA codons, which normally specify termination. This translational “redefinition” of UGA is a highly regulated step that is of interest not only for our understanding of the mechanisms controlling selenoprotein synthesis but because it also provides an opportunity to examine more generally how the processes of translation elongation and decoding can be altered to regulate gene expression. Here we propose to examine the molecular mechanisms of UGA redefinition and its regulation by physiological conditions using a combination of new deep-sequencing approaches and established biochemical methods. In Aim 1, we will test new hypotheses regarding the role of UGA-proximal ribosome pausing and its release when cells undergo endoplasmic reticulum (ER) stress. We propose this phenomenon to be a novel mechanism to rapidly induce selenoprotein expression in response to cellular stress. Further, we will address the biological role that these selenoproteins play in protection from ER stress and the progression to apoptosis. In Aim 2, we examine the role of RNA structures in UGA-proximal ribosome pausing, response to ER stress, and sensing selenium. Finally, in Aim 3, we will utilize high throughput sequencing techniques, mass spectrometry, and RNA structural analysis of selenoprotein ribonucleoprotein complexes isolated directly from tissues of mice to examine the how selenium effects UGA redefinition and selenoprotein expression. These studies will provide new insights into how the control of translational elongation and the very process of decoding can be altered to regulate gene expression.

硒代半胱氨酸在翻译过程中通过一种非常规的机制被掺入硒蛋白中，该机制涉及一种专用的Sec-tRNA，该tRNA解码通常指定终止的UGA密码子。UGA的这种翻译“重新定义”是一个高度调节的步骤，不仅对我们理解控制硒蛋白合成的机制感兴趣，而且因为它也提供了一个机会，更普遍地研究如何改变翻译延伸和解码过程来调节基因表达。在这里，我们建议使用新的深度测序方法和已建立的生化方法相结合，检查UGA重新定义及其生理条件下的调节的分子机制。在目标1中，我们将测试新的假设，UGA近端核糖体暂停和释放的作用时，细胞经历内质网（ER）的压力。我们提出这种现象是一种新的机制，以快速诱导硒蛋白的表达在细胞应激反应。此外，我们将讨论这些硒蛋白在保护ER应激和凋亡进展中的生物学作用。在目标2中，我们研究了RNA结构在UGA近端核糖体暂停、对ER应激的反应和感测硒中的作用。最后，在目标3中，我们将利用高通量测序技术，质谱，和RNA结构分析的硒蛋白核糖核蛋白复合物直接从小鼠组织中分离，以研究硒如何影响UGA的重新定义和硒蛋白的表达。这些研究将为如何改变翻译延伸的控制和解码过程以调节基因表达提供新的见解。