Synergistic Activation of the Human Type II 3β-Hydroxysteroid Dehydrogenase/Δ5-Δ4Isomerase Promoter by the Transcription Factor Steroidogenic Factor-1/Adrenal 4-binding Protein and Phorbol Ester

摘要: Abstract Steroidogenic factor-1/adrenal 4-binding protein (SF-1/Ad4BP) is an orphan nuclear receptor/transcription factor known to regulate the P450 steroid hydroxylases; however, mechanisms that activity of SF-1/Ad4BP are not well defined. In addition, little about human steroidogenic enzyme, type II 3β-hydroxysteroid dehydrogenase (3β-HSD II), major gonadal and adrenal isoform. Regulation 3β-HSD promoter was examined using cortical (H295R; steroidogenic) cervical (HeLa; non-steroidogenic) carcinoma cells. H295R cells were transfected with a series 5′ deletions 1251 base pairs (bp) 5′-flanking region fused chloramphenicol acetyltransferase (CAT) reporter gene followed by treatment or without phorbol ester (phorbol 12-myristate 13-acetate; PMA). CAT assay data indicated from −101 −52 bp required for PMA-induced expression. A putative regulatory element, TCAAGGTAA, identified sequence homology at −64 −56 promoter. Cotransfection HeLa 3β-HSD-CAT construct expression vector increased 49-fold. Subsequent PMA induced unexpected synergistic increase in transcriptional 540-fold over basal. Mutation response element (TCAATAA TCAATAA) abolished SF-1-induced PMA. Gel mobility shift assays confirmed interacts transcripts detected Northern analysis. These first demonstrate 1) regulation non-cytochrome enzyme SF-1/Ad4BP, 2) powerful effect on SF-1/Ad4BP-induced transcription, 3) importance