ARNT2 Is Not Required for TCDD Developmental Toxicity in Zebrafish

Prasch, A.L., Heideman, W., and Peterson, R.E.
Toxicological sciences : an official journal of the Society of Toxicology   82(1): 250-258 (Journal)
Registered Authors
Heideman, Warren, Peterson, Richard E., Prasch, Amy
AHR2; ARNT2; TCDD toxicity; zebrafish; development
MeSH Terms
  • Abnormalities, Drug-Induced*/genetics
  • Animals
  • Animals, Genetically Modified
  • Aryl Hydrocarbon Receptor Nuclear Translocator
  • Dose-Response Relationship, Drug
  • Embryo, Nonmammalian/drug effects
  • Embryo, Nonmammalian/metabolism
  • Embryo, Nonmammalian/pathology
  • Gene Expression Regulation, Developmental/drug effects*
  • Morpholines/pharmacology
  • Oligodeoxyribonucleotides, Antisense/pharmacology
  • Receptors, Aryl Hydrocarbon/biosynthesis*
  • Receptors, Aryl Hydrocarbon/genetics
  • Teratogens/toxicity*
  • Toxicity Tests
  • Transcription Factors/biosynthesis*
  • Transcription Factors/genetics
  • Zebrafish/embryology*
  • Zebrafish/genetics
  • Zebrafish Proteins/biosynthesis*
  • Zebrafish Proteins/genetics
15282404 Full text @ Toxicol. Sci.
ZfAHR2 has been identified as the receptor that is essential for mediating the developmental toxicity caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in zebrafish. One form of zfARNT2, zfARNT2b, forms a functional heterodimer with zfAHR2 that specifically recognizes XREs in gel shift experiments and induces XRE-driven transcription in COS-7 cells treated with TCDD. However, it has not been demonstrated that zfARNT2b acts as the physiological dimerization partner for zfAHR2 to mediate TCDD toxicity in developing zebrafish. An antisense morpholino targeted against zfARNT2 (zfarnt2-MO) along with a line of mutant zebrafish lacking expression of the zfarnt2 gene have been used to test the hypothesis that zfARNT2 mediates the developmental toxicity of TCDD. Injection of the zfarnt2-MO decreased expression of the zfARNT2 protein but did not provide any protection against the formation of pericardial edema at 72 hpf. In addition, in TCDD dose response studies the zfarnt2(-/-) embryos showed no protection against three endpoints of TCDD toxicity observed at 96 hpf: pericardial edema, reduced trunk blood flow, and shortened lower jaw. Finally, immunostaining results at 96 hpf demonstrate that the zfarnt2(-/-) embryos show a similar pattern of TCDD-induced zfCYP1A expression as WT embryos These results demonstrate that zfARNT2 is not essential for mediating TCDD developmental toxicity in zebrafish and suggest that alternate dimerization partner(s) exist for zfAHR2 in vivo.
Genes / Markers
Show all Figures
Mutation and Transgenics
Human Disease / Model Data
Sequence Targeting Reagents
Engineered Foreign Genes
Errata and Notes