Cytochrome P450 (CYP) of chicken and other avian species have been studied primarily with microsomes or characterized by cloning and protein expression. However, the overall existing isoforms in avian CYP1-3 families or dominant isoforms in avian xenobiotic metabolism have not yet been elucidated. In this study, we aimed to clarify and classify all of the existing isoforms of CYP1-3 in avian species using available genome assemblies for chicken, zebra finch, and turkey. Furthermore, we performed qRT-PCR assay to identify dominant CYP genes in chicken liver. Our results suggested that avian xenobiotic-metabolizing CYP genes have undergone unique evolution such as CYP2C and CYP3A genes, which have undergone avian-specific gene duplications. qRT-PCR experiments showed that CYP2C45 was the most highly expressed isoform in chicken liver, while CYP2C23b was the most highly induced gene by phenobarbital. Considering together with the result of further enzymatic characterization, CYP2C45 may have a dominant role in chicken xenobiotic metabolism due to the constitutive high expression levels, while CYP2C23a and CYP2C23b can be greatly induced by chicken xenobiotic receptor (CXR) activators. These findings will provide not only novel insights into avian xenobiotic metabolism, but also a basis for the further characterization of each CYP gene.
Ohtsuki S, Schaefer O, Kawakami H, Inoue T, Liehner S et al. (2011) Simultaneous Absolute Protein Quantification of Transporters, Cytochromes P450, and UDP-Glucuronosyltransferases as a Novel Approach for the Characterization of Individual Human Liver: Comparison with mRNA Levels and Activities. Drug Metab Dispos 40: 83-92. PubMed: 21994437.
Temesvári M, Kóbori L, Paulik J, Sárváry E, Belic A et al. (2012) Estimation of Drug-Metabolizing Capacity by Cytochrome P450 Genotyping and Expression. J Pharmacol Exp Ther 341: 294-305. doi:10.1124/jpet.111.189597. PubMed: 22262920.
Cai H, Jiang J, Yang Q, Chen Q, Deng Y (2012) Functional Characterization of a First Avian Cytochrome P450 of the CYP2D Subfamily (CYP2D49). PLOS ONE 7: e38395. doi:10.1371/journal.pone.0038395. PubMed: 22675558.
J？nsson ME, Woodin BR, Stegeman JJ, Brunstr？m B (2011) Cytochrome P450 1 genes in birds: evolutionary relationships and transcription profiles in chicken and Japanese quail embryos. PLOS ONE 6: e28257. doi:10.1371/journal.pone.0028257. PubMed: 22164255.
Kubota A, Stegeman JJ, Goldstone JV, Nelson DR, Kim EY et al. (2011) Cytochrome P450 CYP2 genes in the common cormorant: Evolutionary relationships with 130 diapsid CYP2 clan sequences and chemical effects on their expression. Comp Biochem Physiol C 153: 280-289. PubMed: 21130899.
Baader M, Gnerre C, Stegeman JJ, Meyer UA (2002) Transcriptional activation of cytochrome P450 CYP2C45 by drugs is mediated by the chicken xenobiotic receptor (CXR) interacting with a phenobarbital response enhancer unit. J Biol Chem 277: 15647-15653. doi:10.1074/jbc.M109882200. PubMed: 11867618.
Ourlin JC, Baader M, Fraser D, Halpert JR, Meyer UA (2000) Cloning and Functional Expression of a First Inducible Avian Cytochrome P450 of the CYP3A Subfamily (CYP3A37). Arch Biochem Biophys 373: 375-384. doi:10.1006/abbi.1999.1566. PubMed: 10620362.
Hackett SJ, Kimball RT, Reddy S, Bowie RCK, Braun EL et al. (2008) A phylogenomic study of birds reveals their evolutionary history. Science 320: 1763-1768. doi:10.1126/science.1157704. PubMed: 18583609.
Tamura K, Peterson D, Peterson N, Stecher G, Nei M et al. (2011) MEGA5: molecular evolutionary genetics analysis using maximum likelihood, evolutionary distance, and maximum parsimony methods. Mol Biol Evol 28: 2731-2739. doi:10.1093/molbev/msr121. PubMed: 21546353.
Nelson DR, Zeldin DC, Hoffman SMG, Maltais LJ, Wain HM et al. (2004) Comparison of cytochrome P450 (CYP) genes from the mouse and human genomes, including nomenclature recommendations for genes, pseudogenes and alternative-splice variants. Pharmacogenet Genomics 14: 1–18. PubMed: 15128046.
Ikushiro S, Sahara M, Emi Y, Yabusaki Y, Iyanagi T (2004) Functional co-expression of xenobiotic metabolizing enzymes, rat cytochrome P450 1A1 and UDP-glucuronosyltransferase 1A6, in yeast microsomes. Biochim Biophys Acta 1672: 86-92. doi:10.1016/j.bbagen.2004.02.012. PubMed: 15110090.
Cheng JB, Levine MA, Bell NH, Mangelsdorf DJ, Russell DW (2004) Genetic evidence that the human CYP2R1 enzyme is a key vitamin D 25-hydroxylase. Proc Natl Acad Sci USA 101: 7711-7715. doi:10.1073/pnas.0402490101. PubMed: 15128933.
Chuang SS (2003) CYP2U1, a novel human thymus- and brain-specific cytochrome P450, catalyzes omega- and (omega-1)-hydroxylation of fatty acids. J Biol Chem 279: 6305-6314. doi:10.1074/jbc.M311830200. PubMed: 14660610.
Blevins S, Siegel PB, Blodgett DJ, Ehrich M, Lewis RM (2012) Liver enzymes in White Leghorns selected for the sheep red blood cell immune response. Poult Sci 91: 322-326. doi:10.3382/ps.2011-01764. PubMed: 22252343.
Rawal S, Mendoza KM, Reed KM, Coulombe RA Jr. (2009) Structure, Genetic Mapping, and Function of the Cytochrome P450 3A37 Gene in the Turkey (Meleagris gallopavo). Cytogenet Genome Res 125: 67-73. doi:10.1159/000218748. PubMed: 19617698.
Handschin C, Podvinec M, Meyer UA (2000) CXR, a chicken xenobiotic-sensing orphan nuclear receptor, is related to both mammalian pregnane X receptor (PXR) and constitutive androstane receptor (CAR). Pro Natl Acad Sci 97:10769-10774.
Goriya HV, Kalia A, Bhavsar SK, Joshi CG, Rank DN, Thaker AM (2005) Comparative evaluation of phenobarbital-induced CYP3A and CYP2H1 gene expression by quantitative RT-PCR in Bantam, Bantamized White Leghorn and White Leghorn chicks. J Vet Sci 6: 279–285. PubMed: 16293989.
Hansen AJ, May BK (1989) Sequence of a chicken phenobarbital-inducible cytochrome P450 cDNA: regulation of two P450 mRNAs transcribed from different genes. DNA 8: 179-191. doi:10.1089/dna.1.1989.8.179. PubMed: 2470563.