SEQUENCE OF THE RAT PB-INDUCIBLE CYP2B1 PROMOTER

The 5' flanking region of the rat PB-inducible CYP1B1 gene was isolate d and the sequence from +27 to -3878 was determined. This sequence con tains several putative binding sites for the liver-enriched factors HN F3 as well as an AP1, two NF-kappa B and several possible STAT sites. The promoter sequence of the CYP2B1 gene was compared to that of the C YP2B2 sequence, published by Hoffman et al. ((1992) Gene Exp. 2, 353-3 62) and was found to be almost identical up to -2300 bp, beyond which it diverges significantly from the remaining published sequence of CYP 2B2 gene. Transient transfection experiments in the differentiated hep atoma cell line, FGC4, showed that the 3.9 kb promoter was expressed, however, an increase in reporter activity was not observed in the pres ence of phenobarbital.