MOLECULAR BASIS FOR SELENIUM DIETARY REQUIREMENT

硒膳食需求的分子基础

• 批准号: 2518289
• 负责人: MERRILL CHRISTENSEN
• 金额: $ 16.11万
• 依托单位: BRIGHAM YOUNG UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-04-01 至 1999-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2518289
• 关键词: analytical method; computer assisted sequence analysis; dietary trace element; enzyme activity; gene expression; genetic library; genetic regulation; genetic transcription; glutathione peroxidase; laboratory rat; messenger RNA; method development; molecular cloning; northern blottings; nuclear runoff assay; nucleic acid sequence; nutrient requirement; nutrition related tag; polymerase chain reaction; selenium

The broad, long-term objective of this work is to establish the molecular basis for selenium (Se) nutrient requirement. Selenium is an essential trace element in the diets of man and animals. However, the mechanisms for many of its biological effects remain unexplained. Unfortunately there is no single, comprehensive experiment that can be designed to answer the question "What other physiological processes depend on Se intake?" or "What other enzymes depend on Se for activity?". However, using the techniques of modern biology, it is possible to ask and answer the questions "What genes are regulated by Se?" and "How are they regulated?". By identifying such genes, the products for which they code, and the mechanisms of their regulation, additional functions for Se will be revealed. Mechanisms for previously observed biological effects of Se will be suggested. New markers for Se nutritional status may be discovered. In addition, the foundation will be established to explore the genetic basis for variability in Se nutrient requirement. Specific Aim 1 in this project is to isolate rat cDNAs for genes whose expression is varied by changes in dietary Se intake. Specific Aim 2 is to determine the pretranslational reaction(s) in the expression of these genes most dependent on dietary intake of Se. Rats will be fed diets inadequate, adequate and high but nontoxic in Se. The techniques of differential display of mRNA will be used to identify and clone cDNAs for genes expressed at different levels in tissues of rat consuming different levels of Se. The sequences of these differentially expressed clones will be compared to those entered into GenBank and other data bases to determine if they represented previously characterized or newly discovered genes, whose expression is regulated by Se intake. These experiments will accomplish Specific Aim 1. For each of these genes, run-on transcription assays and Northern blot analyses will show whether gene transcription or mRNA stabilization is the step in pretranslational gene expression most sensitive to Se intake. Comparison among sequences in the UTRs of cDNAs for Se-regulated genes will show sequences conserved among these different species which may serve as Se-responsive elements. These experiments will accomplish Specific Aim 2.

这项工作的广泛、长期目标是建立分子 硒 (Se) 营养需求的基础。 硒是人体必需的元素 人类和动物饮食中的微量元素。 然而，这些机制 因为它的许多生物效应仍然无法解释。 很遗憾 没有单一的、综合的实验可以设计 回答问题“还有哪些其他生理过程依赖于 Se 摄入量？”或“还有哪些酶的活性依赖于硒？”。但是， 使用现代生物学技术，可以提问和回答 “哪些基因受硒调节？”的问题 和“他们怎么样 受到监管吗？”。通过识别这些基因，它们所产生的产品 代码及其监管机制、附加功能 Se将被揭露。 先前观察到的生物机制 将提出 Se 的影响。 硒营养状况的新标记 可能会被发现。 此外，还将设立该基金会 探索硒营养需求变异的遗传基础。 该项目的具体目标 1 是分离大鼠 cDNA 的基因，这些基因 表达随膳食硒摄入量的变化而变化。 具体目标 2 是 确定这些表达中的翻译前反应 最依赖饮食中硒摄入量的基因。 老鼠将被喂食 硒含量不足、充足、高但无毒。 的技术 mRNA 的差异展示将用于鉴定和克隆 cDNA 摄入不同物质的大鼠组织中基因表达水平不同 Se 水平。 这些差异表达克隆的序列 将与输入 GenBank 和其他数据库的数据进行比较 确定它们是否代表先前特征或新特征 发现了其表达受硒摄入量调节的基因。 这些 实验将实现具体目标 1。对于每个基因， 连续转录测定和 Northern blot 分析将显示是否 基因转录或 mRNA 稳定是翻译前的步骤 基因表达对硒摄入最敏感。 序列间比较 Se 调控基因 cDNA 的 UTR 中将显示保守序列 在这些不同的物种中，它们可以作为硒响应元素。 这些实验将实现具体目标 2。