Regulation of Involucrin Gene Expression by Retinoic Acid and Glucocorticoids1

Involucrin is a major component of the comified envelope and a marker for terminal differentiation in keratinocytes. We examined hormone regulation of involucrin mRNA expression and transcriptional modulation of the involucrin gene in human keratinocyte cell lines. Dexamethasone enhanced, and retinoic acid decreased, endogenous involucrin mRNA expression in cells treated with these ligands. Functional interactions between each ligand were observed; all-trans or 9-cis retinoic acid reduced dexamethasone enhancement of involucrin expression. Transcriptional control of the involucrin promoter reflected the responses observed for the endogenous gene. All-trans or 9-cis retinoic acid inhibited involucri