Partial sequence and polymerase chain reaction-mediated analysis of expression of the human CYP2C18 gene

We describe the isolation of the human CYP2C18 gene, a new member in the complex CYP2C subfamily, associated with the genetically-determined polymorphism for (S)-mephenytoin hydroxylase. The 5' end of CYP2C18 gene was isolated from a human genomic library using a probe derived from the CYP2C10 cDNA and the 5' flanking region, exons 1 to 4 and intron-exon junctions were sequenced. With respect to intron-exon boundaries, the partial gene structure was identical to that of rat and rabbit CYP2C genes. Consensus sequences for putative 'glucocorticoid responsive elements' were observed in the 5' flanking region and in intron 1, an interesting feature in a so-called constitutively-expressed gene subfamily. The knowledge of CYP2C gene sequences is a prerequisite to genomic analysis by PCR techniques. Using oligonucleotides derived from the gene sequence, we were able to specifically detect CYP2C18 mRNAs in human liver.