EGR-1, a UV-inducible gene in p53(-/-) mouse cells

Changes in gene expression were examined in p53(-/-) and p53(+/+) mouse cel ls after ultraviolet (UV) irradiation. Differential display was used to ide ntify differentially expressed gene(s) in UV-treated p53(-/-) and p53(+/+) cells. One of the differentially expressed genes was EGR-1 (early growth re sponse gene-1), which was shown to be induced only in p53(-/-) cells. The i nduction of this gene by UV was detected as early as 0.5 h, peaked at 2 h, and returned to normal levels by 4 h. De novo protein synthesis was not req uired for UV-induced EGR-1 expression in p53(-/-) cells. Pretreatment of p5 3(-/-) cells with suramin, an inhibitor of growth factor receptors, complet ely suppressed W-induced EGR-1 expression, suggesting that the induction ma y be mediated via the growth factor receptors. The presence of wild-type p5 3 suppressed the induction of EGR-1 after UV treatment. Overexpression of E GR-1 promoted the UV-induced transformation in p53(+/+) cells, but not in p 53(-/-) cells. These data suggested that EGR-1 may be an important player i n the UV responses of mammalian cells and may influence UV-induced transfor mation. (C) 2001 Academic Press.