Recently, we showed that the major species of beta-naphthoflavone-inducible rat liver mitochondrial P450MT2 consists of N-terminal truncated microsomal P4501A1 (+33/1A1) and that the truncated enzyme exhibits different substrate specificity as compared with intact P4501A1. The results of the present study show that P450MT2 targeted to COS cell mitochondria by transient transfection of P4501A1 c...

The aryl hydrocarbon receptor (AhR) transcription factor is increasingly recognized as functioning in cell cycle control. Several recent reports have shown that AhR activity in the absence of exogenous agonists or presence of the prototypical ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin can affect G1 phase progression in cultured cells. Serum release of serum-starved (G0) 5L rat hepatoma cells tr...

Cytochrome P4501A1 is a hepatic, microsomal membrane-bound enzyme that is highly induced by various xenobiotic agents. Two NH2-terminal truncated forms of this P450, termed P450MT2a and MT2b, are also found localized in mitochondria from beta-naphthoflavone-induced livers. In this paper, we demonstrate that P4501A1 has a chimeric NH2-terminal signal that facilitates the targeting of the protein...

Cytochrome P4501A1 is a substrate-inducible microsomal enzyme that oxygenates polycyclic aromatic hydrocarbons, such as the carcinogen benzo(a)pyrene, as the initial step in their metabolic processing to water-soluble derivatives. Enzyme induction reflects increased transcription of the cognate CYP1A1 gene. The environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin is the most potent known ...

Cytochrome P4501A1 is a hepatic, microsomal membrane–bound enzyme that is highly induced by various xenobiotic agents. Two NH 2 -terminal truncated forms of this P450, termed P450MT2a and MT2b, are also found localized in mitochondria from b -naphthoflavone–induced livers. In this paper, we demonstrate that P4501A1 has a chimeric NH 2 -terminal signal that facilitates the targeting of the prote...

The induction of microsomal cytochrome P4501A1 by polycycic aromatic hydrocarbons represents an interesting response by which mammalian cells adapt to xenobiotic exposure. Enzyme induction reflects increased transcription of the corresponding CYP1A1 gene. Analyses of the induction mechanism using genetic, biochemical, and molecular biological approaches have revealed a novel transcriptional reg...