Genetic Determinants of Hyperoxia Stress

这项建议的总体目标是了解细胞中高氧敏感性的遗传决定因素。高氧或暴露于高于正常氧浓度的环境中，是一个重要的健康问题，因为它会导致严重的肺部相关损伤。据推测，高氧中毒涉及活性氧的产生；然而，关于影响这种损害的因素知之甚少。以酿酒酵母菌为模型系统，鉴定并表征其抗高氧损伤的基因。酵母缺失突变体完整文库的遗传筛选已经启动，确定突变体对高氧敏感。初步结果表明，对高氧的保护涉及一组抗氧化因子，这是不同于这种类型的氧化应激。在未来的研究中，这种基因筛选将完成（目标1），我们将开始解决高氧损伤的机制（目标2）。将测试突变体对其他氧化剂的敏感性，并探索金属在高氧毒性中的潜在作用。我们选择了一种特殊的高氧突变体pos5进行详细分析（目的3）。POS5编码一种基于同源性的未知蛋白，可能影响细胞表面铁还原酶活性。探讨铁还原酶、铁和POS5在抗高氧中毒中的可能联系。

The overall goal of this proposal is to understand the genetic determinants of hyperoxia sensitivity in the cell. Hyperoxia, or exposure to higher than normal oxygen concentrations, is an important health problem since it can lead to serious lung-related injury. Presumably, toxicity from hyperoxia involves the production of reactive oxygen species; however, very little is known regarding the factors that influence this damage. Using Saccharomyces cerevisiae as a model system, genes that protect against hyperoxia damage will be identified and characterized. A genetic screen of the complete library of yeast deletion mutants has been initiated, identifying mutants that are sensitive to hyperoxia. Initial results indicate that protection against hyperoxia involves a set of antioxidant factors that is distinct for this type of oxidative stress. In future studies, this genetic screen will be completed (Aim 1), and we will begin to address the mechanisms underlying hyperoxia damage (Aim 2). The mutants will be tested for sensitivity to other oxidants and a potential role for metals in hyperoxia toxicity will be explored. One particular hyperoxia mutant has been selected for analysis in detail: pos5 (Aim 3). POS5 encodes an uncharacterized protein, that based on homology, may influence cell surface ferrireductase activity. The possible connection between ferrireductase, iron and POS5 in guarding against toxicity from hyperoxia will be explored.