Many Superfund site toxicants exert their chronic toxicity by causing damage to cellular macromolecules via oxidative stress. Exposure to such pro-oxidants also results in induction of a gene expression program whose primary function is to protect cells from oxidative stress. Little is known about the components of the mammalian oxidative stress response and its regulatory logic. To rectify these deficiencies, Project 1 will use a variety of genetic, cell biological and biochemical approaches to investigate the role of already identified stress activated protein kinases in the mammalian response to oxidative stress, identify new components of this induction responses and determine the mechanism of gene induction by a few model toxicants found at Superfund sites, such as arsenite and carbon tetrachloride. We will also search for new regulatory molecules, including protein kinases and transcription factors, involved in the oxidative stress response. Once identified, the pathophysiological function of these molecules will be analyzed through generation of constitutive and conditional knockout mouse mutants. We will investigate how such genetic alterations affect the ability of these animals or cells derived from them to withstand exposure to Superfund site toxicants that are believed to act via induction of oxidative stress. In addition to elucidating the basic regulatory logic underlying the mammalian response to oxidative stress, this project will have two practical outcomes relevant to the mission of the Superfund Research Program; it will create: 1) gene arrays, cell lines and transgenic mice that can be used as biosensors for monitoring exposure to toxicants that cause oxidative stress; 2) strains of mice that are deficient in activation of the protective response to oxidative stress. Such mice should be supersensitive to pro-oxidants and thus will facilitate the detection and evaluation of new suspected toxicants and mixtures of chemicals from Superfund Sites for their ability to cause oxidative stress mediated toxicity. To accomplish these goals this project will collaborate and interact with Projects 2, 3, 4 and 5 and will rely on all research support cores.