Isolation and phylogeny of novel cytochrome P450 genes from tunicates (Ciona spp.) : a CYP3 line in early deuterostomes?

Author Posting. © Elsevier B.V., 2006. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Molecular Phylogenetics and Evolution 40 (2006): 760-771, doi:10.1016/j.ympev.2006.04.017.Cytochromes P450 (CYPs) form a gene superfamily involved in the biotransformation of numerous endogenous and exogenous natural and synthetic compounds. In humans, CYP3A4 is regarded as one of the most important CYPs due to its abundance in liver and its capacity to metabolize more than 50% of all clinically used drugs. It has been suggested that all CYP3s arose from a common ancestral gene lineage that diverged between 800 and 1100 million years ago, before the deuterostome-protostome split. While CYP3s are well known in mammals and have been described in lower vertebrates, they have not been reported in non-vertebrate deuterostomes. Members of the genus Ciona belong to the tunicates, whose lineage is thought to be the most basal among the chordates, and from which the vertebrate line diverged. Here we describe the cloning, exon-intron structure, phylogeny, and estimated expression of four novel genes from Ciona intestinalis. We also describe the gene structure and phylogeny of homologous genes in Ciona savignyi. Comparing these genes with other members of the CYP clan 3, show that the Ciona sequences bear remarkable similarity to vertebrate CYP3A genes, and may be an early deuterostome CYP3 line.These studies were supported in part by NIH grant 2-P42-ES07381 to J.J. Stegeman. Tim Verslycke was supported by the Postdoctoral Scholar Program at the Woods Hole Oceanographic Institution, with funding from the Ocean Life Institute and by a Fellowship of the Belgian American Educational Foundation. Jared Goldstone was supported by a Ruth Kirschstein National Research Service Award (NIH 5F32ES 012794)