Isolation and identification of a cytochrome P450 sequence in an Australian termite, Mastotermes darwiniensis

A partial cytochrome P450 sequence was RT/PCR amplified from total RNA isolated from the whole body of worker class termites (Mastotermes darwiniensis). The degenerate primers used were designed from conserved regions from 4 different species: rat, human, cockroach and drosophila. The sequence was defined by the presence of the typical P450 heme-binding region and invariant residues found in all P450 proteins. The deduced amino acid sequence is 67% identical to cockroach (Blaberus discoidalis) CYP4C1, with only 39% and 42% identity to either CYP4A1 or CYP4B1, respectively, and has been named CYP4C8. Similar low sequence homology was observed between the termite sequence and the mouse CYP3a16 (39%) and blackswallow butterfly CYP6B3 (41%) P450 proteins. The CYP4C8 sequence contains variations in the 13-residue sequence characteristic of family 4 members, distinct from those seen for CYP4D1 and CYP4F family members, M. darwiniensis has been proposed as the 'missing link between cockroaches and termites,' with the genus Mastotermes dating back some 20-40 million years. The phylogenetic distance between B. discoidalis and M. darwiniensis would suggest that CYP4C8 represents the most ancient of the CYP4 family members.