Transcriptional regulation of cytochrome P-450b/e gene expression in rat liver

Abstract

The regulatory features of the transcriptional activation of the cytochrome P-450IIB1/B2(b/e) genes in rat liver by phenobarbitone have been examd. Heme as a pos. modulator, and dexamethasone modulator of the action of the pos. activator were examd. The upstream sequence within -179 nucleotides of the cytochrome P-450b/e genes has been found to respond to the various regulatory features mentioned. Apparently, phenobarbitone induces a set of transcription factors leading to the transcriptional activation of the P-450b/e genes in rat liver. Conditions resulting in an interference with the-drug mediated increase in transcription are invariably assocd. with a decrease in the interaction of 90Kd proteins with an upstream sequence. The cytochrome P-450b/e genes also manifest elongation regulation at the level of transcription.