IDENTIFICATION OF A GLUCOCORTICOID RESPONSE ELEMENT IN THE HUMAN TRANSFORMING-GROWTH-FACTOR-BETA-1 GENE PROMOTER

TGF-beta 1, which has a stimulatory effect on dermal wound healing, ha s been implicated as the primary causative agent of fibrosis. Glucocor ticoids such as dexamethasone normally inhibit wound healing and are c apable of antagonizing the fibrotic effect of TGF-beta 1. Our data ind icate the presence of a putative regulatory element responsive to gluc ocorticoids. Computer sequence analysis of the promoter region of the human TGF-beta 1 gene (Genbank Accession # J04431) revealed a consensu s glucocorticoid response element, GRE (5'-AGAACA) located from (-1081 ) to (-1086) base pairs from the transcription start site. An oligonuc leotide containing this site was obtained and labeled for use in gel m obility shift assays. The labeled oligonucleotide was found to bind bo th fetal rat skin nuclear- extracts and purified recombinant glucocort icoid receptor. Unlabeled oligonucleotides containing a GRE from the r at procollagen type 1 promoter or a commercially supplied GRE competed effectively with the P-32-labeled GRE from the TGF-beta 1 promoter fo r binding to nuclear extracts. Addition of anti-glucocorticoid recepto r revealed a supershifting of the labeled oligonucleotide-nuclear prot ein complex. These results indicate the presence of a putative GRE in the promoter region of the human TGF-beta 1 gene. (C) 1998 Elsevier Sc ience Ltd. All rights reserved.