AN EXPRESSIONAL SYSTEM OF HUMAN CYTOCHROME-P-450 CYP1A1 GENE-TRANSCRIPTION

AIM: To explore an expressional system of human cytochrome P-450 CYP1A 1 (CYP1A1) gene transcription. METHODS: The plasmid PMC 6.3 K containi ng human CYP1A1 promoter was transiently transfected into Hep G2 cells . The expression of chloramphenical acetyltransferase (CAT) reporter g ene was detected by ELISA. RESULTS: Both the CAT expression and CYP1A1 activity increased with the concentrations of beta-naphthoflavone fro m 2.5 to 10 mu mol . L-1. At 10 mu mol . L-1 of beta-naphthoflavone, t he levels of CAT and CYP1A1 were 94-fold and 2.8-fold those of the cor responding control, respectively. Using this method, the study of 8 gl ucosinolates with various side chains on the induction of CYP1A1 gene transcription showed that none of the parent glucosinolates increased CAT expression, whereas the breakdown products of indol-3-yl-methyl gl ucosinolate ( glucobrassicin), rather than indole-3-carbinol, increase d the CAT expression. CONCLUSION: The CYP1A1 gene transcriptional syst em was more reliable and sensitive.