Expression of CYP2A genes in human liver and extrahepatic tissues

Members of the human cytochrome P450 ZA (CYP2A) subfamily are known to meta bolize several promutagens, procarcinogens, and pharmaceuticals. In this st udy, the expression of the three genes found in the human CYP2A gene cluste r was investigated in the liver and several extrahepatic tissues by gene-sp ecific reverse transcriptase polymerase chain reaction (RT-PCR). All three transcripts (CYP2A6, CYP2A7, and CYP2A13) were found to be present in liver , Quantitative RT-PCR analysis showed that CYP2A6 and CYP2A7 mRNAs were pre sent at roughly equal levels in the liver, while CYP2A13 was expressed at v ery low levels. Two putative splicing variants of CYP2A7 were found in the liver. Nasal mucosa contained a low level of CYP2A6 and a relatively high l evel of CYP2A13 transcripts. Kidney, duodenum, lung, alveolar macrophages, peripheral lymphocytes, placenta, and uterine endometrium were negative for all transcripts. This survey gives a comprehensive picture of the expressi on pattern of CYP2A genes in liver and extrahepatic tissues and constitutes a basis for a search for functional CYP2A forms and their roles in chemica l toxicity in liver and nasal mucosa. (C) 1999 Elsevier Science Inc.