Cell-type specificity of human CYP11A1 TATA box

Expression of the CYP11A1 (SCC) genes, which encode the enzyme important for the first step of steroid biosynthesis, occurs in the adrenal gland and gonads, and is stimulated by cAMP. Transfection of serial deletions of the SCC promoter, which drives reporter gene expression, showed that a minimal promoter containing only the TATA box could direct cAMP-dependent transcription. Transcription factor SF1. which binds to a site next to the TATA box, can stimulate basal transcription but not cAMP response, either in adrenal cell lines or in COS-1 co-transfected with the SF1 expression plasmid. These data lead to the conclusion that the minimal promoter containing only the TATA box can drive cell type-specific, cAMP-dependent transcription, Additional experiments replacing the TATA sequence of SCC with other TATA sequences suggested that the TATA sequence itself is important for this cAMP-dependent transcription. (C) 1999 Elsevier Science Ltd. All rights reserved.