The K14 keratin is an intermediate filament produced in squamous epith
elia. This tissue-specific expression is directed by the promoter (pK1
4) of the K14 gene which has been used extensively to direct the expre
ssion of transgenes to the skin. Human K14 was cloned and the upstream
sequence is presented. In transient transfections, pK14 directs expre
ssion of a luciferase reporter in keratinocytes much more potently tha
n in breast cancer cells.