cytochrome p450 1 genes in birds evolutionary relationships and transcription profiles in chicken and japanese quail embryos细胞色素p450 1基因在鸟类进化关系和转录资料在鸡肉和日本鹌鹑胚胎.pdf

Cytochrome P450 1 Genes in Birds: Evolutionary Relationships and Transcription Profiles in Chicken and Japanese Quail Embryos ¨ 1,2 2 2 ¨ ¨ 1 Maria E. Jonsson *, Bruce R. Woodin , John J. Stegeman , Bjorn Brunstrom 1 Department of Environmental Toxicology, Uppsala University, Uppsala, Sweden, 2 Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, United States of America Abstract Background: Cytochrome P450 1 (CYP1) genes are biomarkers for aryl hydrocarbon receptor (AHR) agonists and may be involved in some of their toxic effects. CYP1s other than the CYP1As are poorly studied in birds. Here we characterize avian CYP1B and CYP1C genes and the expression of the identified CYP1 genes and AHR1, comparing basal and induced levels in chicken and quail embryos. Methodology/Principal Findings: We cloned cDNAs of chicken CYP1C1 and quail CYP1B1 and AHR1. CYP1Cs occur in several bird genomes, but we found no CYP1C gene in quail. The CYP1C genomic region is highly conserved among vertebrates. This region also shares some synteny with the CYP1B region, consistent with CYP1B and CYP1C genes deriving from duplication of a common ancestor gene. Real-time RT-PCR analyses revealed similar tissue distribution patterns for CYP1A4, CYP1A5, CYP1B1, and AHR1 mRNA in chicken and quail embryos, with the highest basal expression of the CYP1As in liver, and of CYP1B1 in eye, brain, and heart. Chicken CYP1C1 mRNA levels were appreciable in eye and heart but relatively low in other organs. Basal transcript levels of the CYP1As were higher in quail than in chicken, while CYP1B1 levels were similar in the two species. 3,3 9,4,5,5 9-Pentachlorobiphenyl induced all CYP1s in chicken; in quail a 1000-fold higher dose induc