INDUCTION OF THE MAMMALIAN STRESS-RESPONSE GENE GADD153 BY OXIDATIVE STRESS - ROLE OF AP-1 ELEMENT

GADD153 is a CCAAT/enhancer-binding-protein-related gene that may func tion to control cellular growth in response to stress signals. In this study, a variety of oxidant treatments were shown to stimulate endoge nous GADD153 mRNA expression and to transcriptionally activate a GADD1 53 promoter-reporter gene construct in transfected HeLa cells. Both co mmonalities and distinctions in the induction of GADD153 by H2O2 and t he thiol-reactive compound arsenite were demonstrated. GADD153 mRNA in duction by both H2O2 and arsenite was potentiated by GSH depletion, an d completely inhibited by N-acetyl-cysteine. o-Phenanthroline and mann itol blocked GADD153 induction by H2O2, indicating that iron-generated hydroxyl radical mediates this induction. Concordantly, GSH peroxidas e overexpression in WI38 cells attenuated GADD153 mRNA induction by H2 O2. However, GADD153 induction by arsenite was only modestly reduced i n the same cells, suggesting a lesser contribution of peroxides to gen e activation by arsenite. We also demonstrated that oxidative stress p articipates in the induction of GADD153 by UVC (254 nm) irradiation. F inally, both promoter-deletion analysis and point mutation of the AP-1 site in an otherwise intact promoter support a significant role for A P-1 in transcriptional activation of GADD153 by UVC or oxidant treatme nt. Indeed, exposure of cells to oxidants or UVC stimulated binding of Fos and Jun to the GADD153 AP-1 element. Together, these results demo nstrate that both free-radical generation and thiol modification can t ranscriptionally activate GADD153, and that AP-1 is critical to oxidat ive regulation of this gene. This study further supports a role for th e GADD153 gene product in the cellular response to oxidant injury.