GPX1 ENZYME REGULATION BY OXIDATIVE XENOBIOTICS

描述：(改编自《调查者摘要》)氧气代谢 释放被称为自由基的有毒产物，它与许多 人类疾病包括自身免疫、缺血/中风、药物/毒素损伤、 动脉粥样硬化、关节炎、糖尿病、肌萎缩侧索硬化症、衰老和癌症。保护 抗自由基损伤是由抗氧化酶提供的，包括 依赖谷胱甘肽的酶。胞内含硒的谷胱甘肽 过氧化物酶(GPX1)是谷胱甘肽依赖的最重要的保护性物质之一 酵素。虽然关于GPX1调节的详细生化研究已经被 虽然已经完成，但对分子水平的调控知之甚少， 值得注意的是，在应激期间GPX1的诱导。这项提议将 通过表征新的负性和非负性来研究GPX1的调控 5侧翼的正调控元件-非翻译(5‘ntr)或 基因的启动子区域。研究包括DNA足迹，核苷酸 5‘NTR GPX1/Report的突变和序列核苷酸缺失 嵌合结构，以识别组成元素的核苷酸。这个 主要氧化反应元件(ORE3)的DNA结合蛋白将是 与世隔绝。在GPX1的5‘非编码区中发现了一种新的元素ORE4，它可能 抑制GPX1 mRNA的翻译，直到发生氧化应激，类似于 铁蛋白中的铁反应元素(IRE)。研究将确定 该元件及其相应结合蛋白的功能作用 (ORE4-BP(以前隔离)。构成基础或核心的元素 GPX1的表达，以及与组织特异性元件有关的 异常的组织表达的GPX1，将被识别。小鼠GPX1基因 其特征在于允许在基础上与人类GPX1进行比较， 具有氧化反应性和组织特异性的元素。这些研究将 提供有关细胞对氧化应激反应的关键信息 并帮助确定是否存在共同的监管机制 依赖谷胱甘肽的酶。

DESCRIPTION: (Adapted from the Investigator's Abstract) Oxygen metabolism release toxic products called free radicals which are implicated in many human diseases including autoimmune, ischemia/stroke, drug/toxin damage, atherosclerosis, arthritis, diabetes, ALS, aging, and cancer. Protection against free radical damage is provided by antioxidant enzymes including GSH-dependent enzymes. The cytosolic selenium-dependent glutathione peroxidase (GPXl) is one of the most important GSH-dependent protective enzymes. While detailed biochemical studies on GPXl regulation have been accomplished, little is known of regulatory control at a molecular level, notably in regard to induction of GPXl during stress. This proposal will investigate the regulation of GPXl by characterizing novel negative and positive regulatory elements in the flanking 5-nontranslated (5'NTR) or promoter region of the gene. Studies include DNA footprinting, nucleotide mutagenesis, and serial nucleotide deletion from 5'NTR GPXl/reporter chimeric constructs to identify nucleotides comprising the elements. The DNA-binding protein to the major oxidant-responsive element (ORE3) will be isolated. A novel element ORE4 is identified in the 5'UTR of GPX1 that may repress GPXl mRNA translation until oxidative stress occurs, similar to the iron-responsive element (IRE) in ferritin. Studies will determine the functional role of this element and its corresponding binding protein (ORE4-BP (previously isolated). The elements responsible for basal or core GPXl expression, as well as tissue-specific elements responsible for the unusual tissue expression of GPXl, will be identified. The mouse GPXl gene will be characterized to allow comparison to human GPXl in regards to basal, oxidative-responsive, and tissue-specific elements. These studies will provide critical information regarding cellular response to oxidative stress and aid in determining if a common regulatory mechanism exists for GSH-dependent enzymes.