Ultraviolet B radiation induction of ornithine decarboxylase gene expression in mouse epidermis.

The cellular effects of u.v. radiation have been studied by using a hairless-mouse model in vivo. U.v. B radiation (u.v.B) induced the activity of the enzyme ornithine decarboxylase (ODC) in mouse epidermis. Maximal induction was noted after radiation with 90 mJ/cm2, and increased ODC activity was first detected 2 h after u.v.B exposure. U.v.B. also induced the expression of the ODC gene in a time- and dose-dependent manner, but did not induce the levels of actin mRNA transcripts. Cycloheximide treatment did not alter basal levels of ODC mRNA transcripts and had no effect on the u.v.B induction of ODC-gene expression. The results of these experiments demonstrate that u.v.B radiation induces both the expression of the ODC gene and the activity of the enzyme, and provides a useful 'in vivo' paradigm for the analysis of the molecular effects of u.v.B radiation.