Analysis of the control of expression and tissue specificity of the keratin 5 gene, characteristic of basal keratinocytes. Fundamental role of an AP-1 element.

摘要: The keratin 5 gene presents a complex regulation, since it is expressed at different rates in the basal cells of most, if not all, stratified epithelia. We have analyzed 5'-upstream region bovine (BK5) and found that 5.2 kilobases preceding mimic vitro cell type-specific expression BK5. Most transcriptional activity maps to an enhancer located between positions -762 -1009. only regulatory element this by electrophoretic mobility shift, competition, footprinting experiments consensus AP-1 site. Mutation site abolishes reduces 25% 5.2-kilobase upstream promoter region. Surprisingly, although indistinguishable footprints all types tested, active some them. Even oligonucleotide containing protected from DNase I epithelial lines but NIH 3T3 fibroblasts, suggesting could constitute epithelium-specific element. also show BK5 does respond phorbol ester induction, which suggests regulation must be probably several other suprabasal, AP-1-regulated cellular viral genes.