Two forms of cytochrome P450 cDNA from 3-methylcholanthrene-treated European eel Anguilla anguilla

Abstract

The cytochrome P450 (CYP) represents a large group of microsomal monooxygenases that catalyze drugs as well as a host of lethal environmental contaminants such as dioxins, leading to either detoxification and excretion from the animal or generation of carcinogenic intermediates. In the present study two forms of cDNA were cloned (Eu MC1 and Eu MC2) for European eel CYP1A genes by polymerase chain reaction (PCR) techniques. The cDNA of Eu MC1 was 3368 bp long coding 521 amino acid residues, and that of Eu MC2 was 2464 bp long coding 517 amino acid residues. Identities of deduced amino acid sequences between Eu MC1 and Japanese eel CYP1A1 and that between Eu MC2 and the second form of Japanese eel CYP1A were 98% and 97%, respectively, showing decisively that Eu MC1 and Eu MC2 are orthologous to Japanese eel CYP1A1 and the second form of CYP1A, respectively. A striking difference between the two eel species was that the Eu MC1 peptide was two amino acid residues longer than that of the Japanese eel CYP1A1. Existence of two loci of CYP1A in Japanese and European eels may suggest that the two forms of CYP1A exist widely among the eel species, because the divergence between the two eel species has been shown to be close to the basal divergence among eels. The identities in CYP1A may help to estimate genetic distance between European and Japanese eels.

Molecular phylogenies and evolutionary behavior of AhR (aryl hydrocarbon receptor) pathway genes in aquatic animals: Implications for the toxicology mechanism of some persistent organic pollutants (POPs)

“…Fish generally possesses a single CYP1A gene (Morrison et al, 1995(Morrison et al, , 1998; besides, we can find that gold fish clusters in a monophyletic group with other fish CYP1As, and more closely related to zebrafish CYP1A than to other fish CYP1As. However, Rainbow trout and salmonids are notable exceptions, this is consistent with the result of (Rabergh et al, 2000;Mahata et al, 2003). Mammalian, in contrast, generally possesses two paralogous CYP1A genes: CYP1A1 and CYP1A 2 (Kimura et al, 1984;Quattrochi et al 1985).…”

A Revised Evolutionary History of the CYP1A Subfamily: Gene Duplication, Gene Conversion, and Positive Selection

“…Fish generally possess a single CYP1A gene (e.g. Morrison et al, 1995;Morrison et al, 1998); eels and salmonids are notable exceptions (Rabergh et al, 2000;Mahata et al, 2003).…”

Does dexamethasone affect hepatic CYP450 system of fish? Semi-static in-vivo experiment on juvenile rainbow trout

“…This enzyme is highly conservative among vertebrates. Mammals, birds and some fish species (eel and rainbow trout) possess genes for two CYP1A isoforms (Berndtson and Chen, 1994;Rifkind et al, 1994;Gorman et al, 1998;Mahata et al, 2003). A widely used assay for CYP1A is the measurement of EROD activity, which is routinely used as a biomarker to determine the presence of organic pollutants (Mandal, 2005).…”