THE DISTAL REGULATORY REGION OF THE HUMAN INVOLUCRIN PROMOTER IS REQUIRED FOR EXPRESSION IN EPIDERMIS

Human involucrin (hINV) is a precursor of the keratinocyte cornified e nvelope that is specifically expressed in the suprabasal layers of str atifying squamous epithelia. The promoter distal (DRR) and proximal re gulatory regions (PRR) are required for optimal in vitro expression (W elter, J, F,, Crish, J. F., Agarwal, C., and Eckert, R. L, (1995) J. B iol. Chem. 270, 12614-12622; and Banks, E. B., Crish, J. F., Welter, J . F,, and Eckert, R. L. (1998) Biochem. J. 331, 61-68). We now present the complete sequence of these regions and evaluate their ability to drive in vivo transcription. Transgenes containing 5000 or 2473 base p airs of upstream regulatory region drive tissue- and differentiation-a ppropriate expression in stratifying surface epithelia, In contrast, t ransgenes containing 1953, 1333, 986, or 41 base pairs of upstream reg ulatory region are not expressed in surface epithelia, indicating that loss of the DRR (nucleotides -2474/-1953) results in loss of expressi on. Fusing the isolated DRR region directly to the hINV minimal promot er restores surface epithelial expression. Sequences downstream of the transcribed gene are not required for appropriate expression. The -19 53/-41 segment influences the pattern of differentiation-dependent exp ression. The -986/-41 region, which includes the PRR, drives expressio n in internal epithelia.