GPX1 ENZYME REGULATION BY OXIDATIVE XENOBIOTICS

描述：（改编自研究者摘要）氧代谢 释放出称为自由基的有毒产物， 人类疾病，包括自身免疫、局部缺血/中风、药物/毒素损伤， 动脉粥样硬化、关节炎、糖尿病、ALS、衰老和癌症。 保护 抗自由基损伤的抗氧化酶，包括 GSH依赖酶。 胞浆硒依赖型谷胱甘肽 过氧化物酶（GPX 1）是一种重要的GSH依赖性保护酶， 内切酶 虽然对GPX 1调节的详细生物化学研究已经被证实， 虽然已经完成，但对分子水平上的调控知之甚少， 特别是关于应激期间GPX 1的诱导。 这项建议会 通过表征新的负性来研究GPX 1的调节， 侧翼5-非翻译（5 'NTR）或 基因的启动子区域。 研究包括DNA足迹，核苷酸 突变和从5 ′ NTR GPX 1/报告基因中连续缺失核苷酸 嵌合构建体以鉴定包含所述元件的核苷酸。 的 DNA结合蛋白的主要氧化剂反应元件（ORE 3）将是 与世隔绝 在GPX 1的5 'UTR中鉴定了一种新的元件ORE 4， 抑制GPX 1 mRNA翻译，直到发生氧化应激，类似于 铁蛋白中的铁响应元件（IRE）。 研究将确定 该元件及其相应结合蛋白的功能作用 （ORE 4-BP（先前分离的）。 负责基底或核心的元素 GPX 1表达，以及组织特异性元件，负责 将鉴定GPX 1的异常组织表达。 小鼠GPX 1基因 将被表征以允许在基础方面与人GPX 1比较， 氧化反应和组织特异性元素。 这些研究将 提供关于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， GSH依赖酶。

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.