INTEGRIN ALPHA(V) PROMOTER ACTIVITY IN KERATINOCYTES

Background. During reepithelialization keratinocytes show increased ex pression of the integrin subunit alpha(v). We have investigated the pr omoter region of the alpha(v) integrin subunit to learn more about its regulation. Methods. The promoter region of the human integrin alpha( v) gene was cloned into a luciferase reporter vector. Deletional mutan ts were created using PCR. Computerized sequence analysis was performe d using the Wisconsin Package. Gel shift analysis was performed using keratinocyte nuclear extracts and oligonucleotides spanning the region s of interest. Results. Deletion from -522 bp to -235 resulted in no d iscernible effect on promoter activity. In contrast deletion of the ne xt 22 bp, which included a putative ets binding site, reduced activity by approximately half. Further deletion to -139 bp essentially abolis hed promoter activity. Computer searching of this region of the integr in alpha(v) promoter revealed two tandemly repeated motifs, TCCTCCTCC, that had previously been implicated in the function of the epidermal growth factor receptor (EGFR) promoter. Comparison of the alpha(v), in tegrin promoter to the EGFR promoter revealed an area of high homology in this region, Gel-shift analysis revealed binding of a single-stran d specific DNA binding protein to single-stranded oligos comprising th ese motifs, but no binding of factors to the double-stranded oligo con taining the ets binding site. Conclusions. In keratinocytes alpha(v) i ntegrin expression is controlled by a region of the promoter with high homology to the epidermal growth factor receptor promoter. This regio n binds single-strand specific DNA binding proteins that are likely to be important in con trolling transcription. (C) 1998 Academic Press.