EPIDERMAL-KERATINOCYTES - GENES AND THEIR REGULATION

In recent years, the human epidermal keratinocyte has been extensively studied. These studies have shown that epidermal growth factor (EGF), transforming growth factor-beta (TGF beta), retinoids, phorbol ester, vitamin D and other agents regulate keratinocyte proliferation, diffe rentiation, apoptosis and gene expression,We review progress in unders tanding the mechanisms that regulate keratinocyte structural gene expr ession. In most cases little is known regarding the factors that regul ate gene expression in response to a physiological agent. However, the available results suggest a role for a variety of transcription facto rs, including STAT factors, NF kappa B, octamer site (OCT) binding pro teins and activator protein 1 (AP1) factors in regulating expression o f these genes. Among these transcriptional regulators, AP1 appears to play a central role. We review the current literature regarding the re gulation of involucrin, loricin, transglutaminase type 1 and cytokerat in gene expression. This survey indicates that the AP1 family of trans criptional regulators is implicated in the regulation of nearly all of these genes. We also discuss recent studies which describe the distri bution of the AP1 factors, c-jun, junB, junD, Fra-1, Fra-2, c-fos and fosB, in epidermis.