Identification and characterisation of a cytochrome P450 gene and processed pseudogene from an arachnid: the cattle tick, Boophilus microplus

We isolated and sequenced the first known cytochrome P450 gene and pseudoge ne from an arachnid, the cattle tick, Boophilus microplus. Bath the gene an d pseudogene belong to the family CYP4, but a new subfamily, CYP4W, had to be created for these genes because they are substantially different to othe r CYP4 genes. The gene, CPP4W1, has greatest homology with CYP4C1 from a co ckroach, Blaberus discoidalis. The predicted molecular weight of the protei n encoded by CYP4W1 (63 KDa) is greater than that of the other CYP4 genes. The pseudogene, CYP4W1P, is probably a processed pseudogene derived from th e functional gene CYP4W1. This is only the third CYP processed pseudogene t o be identified. The pseudogene is 98% identical to the functional gene, CY P4W1, therefore we hypothesise that this pseudogene evolved recently from t he functional gene. The CYP4 genes from arthropods have diverged from each other more than those of mammals; consequently the phylogeny of the arthrop od genes could not be resolved. (C) 1999 Elsevier Science Ltd. All rights r eserved.