IDENTIFICATION OF TISSUE-SPECIFIC PROTEIN-BINDING DOMAINS IN THE 5'-PROXIMAL REGULATORY REGION OF THE RAT MITOCHONDRIAL BROWN FAT UNCOUPLING PROTEIN GENE

The 5' proximal region of the rat uncoupling protein gene, extending f rom -611 to +110, contains cis-acting elements involved in cell-specif icity and cAMP regulation of transcription. DNAse I footprinting of th is region was performed using protein extracts from brown adipose tiss ue and liver nuclei. Nine protein binding domains were observed using nuclear proteins from both tissues. They include the elements for basa l promoter activity (TATA and CCAAT elements), a cAMP-responsive eleme nt, two C/EBP binding sites and three unidentified DNA-protein binding domains sharing a common GCCCCT sequence. A purine rich region at -40 2/-362 was observed to bind proteins abundant in liver but scarce in b rown adipose tissue nuclei. A single region at -512/-487 was identifie d as the only element that binds nuclear proteins present in brown adi pose tissue but absent in liver. This putative tissue-specific element in the uncoupling protein gene contains a sequence identical to mamma lian or viral gene elements that bind members of the ETS family of tra nscription factors. (C) 1994 Academic Press, Inc.