Transcriptional and posttranslational mechanisms modulating the expression of the cytochrome P450 1A1 gene by lead in HepG2 cells: A role of heme oxygenase

► Pb2+ significantly inhibited the induction of CYP1A1 through transcriptional and posttranslational mechanisms. ► The transcriptional mechanism is evidenced by the decrease in XRE- and increase in ARE-reporter genes. ► The posttranslational mechanism is evidenced by the ability of HO-1 chemical inhibitors and HO-1 knockdown to restore of the Pb2+-mediated effect.