TitleTissue-specific expression of AHR2, ARNT2, and CYP1A in zebrafish embryos and larvae: effects of developmental stage and 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure.
Publication TypeJournal Article
Year of Publication2002
AuthorsAndreasen, EA, Spitsbergen, JM, Tanguay, RL, Stegeman, JJ, Heideman, W, Peterson, RE
JournalToxicol Sci
Date Published2002 Aug
KeywordsAnimals, Aryl Hydrocarbon Receptor Nuclear Translocator, Cardiovascular System, Cytochrome P-450 Enzyme System, Embryo, Nonmammalian, Embryonic and Fetal Development, Gene Expression Regulation, Developmental, In Situ Hybridization, Larva, Polychlorinated Dibenzodioxins, Receptors, Aryl Hydrocarbon, RNA, Messenger, Teratogens, Transcription Factors, Zebrafish, Zebrafish Proteins

To better understand the role of the aryl hydrocarbon receptor (AHR) signaling pathway in causing tissue-specific signs of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxicity in zebrafish, the temporal and spatial expression of the zebrafish aryl hydrocarbon receptor 2 (zfAHR2), aryl hydrocarbon receptor nuclear translocator 2 (zfARNT2), and an AHR regulated gene, cytochrome P4501A (zfCYP1A), were assessed in larvae exposed to vehicle or TCDD (1.55 nM) from 3-4 h postfertilization (hpf). Coexpression of a transcriptionally active AHR pathway was apparent by the expression of zfCYP1A mRNA and protein in certain larval tissues. zfCYP1A protein was first detected in the skin and vasculature of TCDD-exposed larvae at 36 hpf. Vascular-specific zfCYP1A protein expression continued from 36 to120 hpf at which time it was also detected in the heart, kidney, and liver. zfCYP1A mRNA was observed in TCDD treated larvae as early as 24 hpf in the developing vascular system. Vascular specific zfCYP1A mRNA expression in the head, trunk, and tail by 36 hpf in TCDD-exposed larvae, confirmed immunohistochemical localization. The expression of zfAHR2 and zfARNT2 mRNAs was generally similar in control and TCDD-exposed larvae. Coexpression of zfAHR2, zfARNT2, and zfCYP1A mRNAs was evident in TCDD-exposed larvae by 36 hpf and in the vasculature, heart, and trunk kidney by 48 hpf, well before the first signs of overt developmental toxicity are observed. In addition to their function in response to AHR agonists, zfAHR2 and zfARNT2 may be involved in development and function of the nervous system. zfAHR2 and zfARNT2 were detected in the brain, spinal cord, and sensory organs. However, TCDD-induced zfCYP1A expression was not detected in these tissues. Taken together, these results are consistent with the notion that the cardiovascular system is a primary target of TCDD developmental toxicity in zebrafish.

Alternate JournalToxicol. Sci.
PubMed ID12151636
Grant ListR01 ES010820 / ES / NIEHS NIH HHS / United States
ES03850 / ES / NIEHS NIH HHS / United States
ES10820 / ES / NIEHS NIH HHS / United States
P30ES09090 / ES / NIEHS NIH HHS / United States