title: Generation of Tg(cyp1a:gfp) Transgenic Zebrafish for Development of a Convenient and Sensitive In Vivo Assay for Aryl Hydrocarbon Receptor Activity.
abstract: Both dioxins/dioxin-like compounds and polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants and cause multiple adverse health effects on human and wildlife. Cyp1a is the most commonly used biomarker induced by these pollutants through activation of the aryl hydrocarbon receptor (AhR) pathway. Here we generated Tg(cyp1a:gfp) transgenic zebrafish for establishing a convenient in vivo assay for analysing these xenobiotic compounds. The Tg(cyp1a:gfp) larvae at 4 day post-fertilization were tested with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and GFP induction was observed mainly in the kidney, liver and gut. Similar GFP expression was also induced strongly by two dioxin-like chemicals, co-planar polychlorinated biphenyl (PCB126) and polychlorinated dibenzo-p-furan (PeCDF) and relatively weakly by two PAHs, 3-methylcholanthrene (3-MC) and benzo[a]pyrene (BAP). The lowest observed effective concentration (LOEC) of TCDD was estimated to be ∼1 pM and the EC50 (effective concentration to induce GFP in 50 % of Tg(cyp1a:gfp) larvae) was ∼10 pM. PCB126 and PeCDF had ∼10× lower potencies in GFP induction than TCDD, while the potencies for 3-MC and BAP were at least 1000× lower. The sensitivity of Tg(cyp1a:gfp) larvae to respond TCDD was also favourable compared to that of ethoxyresorufin-O-deethylase (EROD) assay in both zebrafish larvae and adult livers. As GFP-based assay in transgenic zebrafish can be easily accommodated in multi-well dishes, the Tg(cyp1a:gfp) zebrafish should provide not only a valuable biomonitoring tool for aquatic contaminants but also a potential high-throughput chemical screening platform for identification of new AhR agonists.
authors.affiliation: Department of Biological Sciences, National University of Singapore, S3-Level 6, 14 Science Drive 4, Singapore, 117543, Singapore.|Pearl River Fishery Research Institute, Chinese Academic of Fishery Sciences, Guangzhou, 510380, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Xu
authors.affiliation: Department of Biological Sciences, National University of Singapore, S3-Level 6, 14 Science Drive 4, Singapore, 117543, Singapore.
authors.forename: Caixia
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Biological Sciences, National University of Singapore, S3-Level 6, 14 Science Drive 4, Singapore, 117543, Singapore.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Biological Sciences, National University of Singapore, S3-Level 6, 14 Science Drive 4, Singapore, 117543, Singapore.
authors.forename: Grace Hwee Boon
authors.initials: GH
authors.lastname: Ng
authors.affiliation: Department of Biological Sciences, National University of Singapore, S3-Level 6, 14 Science Drive 4, Singapore, 117543, Singapore.|College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Chunsheng
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Biological Sciences, National University of Singapore, S3-Level 6, 14 Science Drive 4, Singapore, 117543, Singapore.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Biological Sciences, National University of Singapore, S3-Level 6, 14 Science Drive 4, Singapore, 117543, Singapore. dbsgzy@nus.edu.sg.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Gong
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified / Q000235:genetics* / Q000378:metabolism; D001572:Benzofurans / Q000494:pharmacology; D001681:Biological Assay / Q000379:methods*; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics / Q000378:metabolism; D005260:Female; D008099:Liver / Q000378:metabolism; D011078:Polychlorinated Biphenyls / Q000494:pharmacology; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology; D011108:Polymers / Q000494:pharmacology; D060888:Real-Time Polymerase Chain Reaction; D018336:Receptors, Aryl Hydrocarbon / Q000032:analysis / Q000378:metabolism*; D015027:Zebrafish / Q000235:genetics* / Q000378:metabolism
chemical_list: D001572:Benzofurans; D000072317:Polychlorinated Dibenzodioxins; D011108:Polymers; D018336:Receptors, Aryl Hydrocarbon; C016068:polychlorodibenzofuran; D011078:Polychlorinated Biphenyls; D019363:Cytochrome P-450 CYP1A1; C023035:3,4,5,3',4'-pentachlorobiphenyl
keywords: Aryl hydrocarbon receptor; Cyp1a; Polychlorinated biphenyl (PCB126); Polychlorinated dibenzo-p-furan (PeCDF); TCDD; Zebrafish