PUBLICATION

The vas::egfp transgenic zebrafish: A practical model for studies on the molecular mechanisms by which environmental estrogens affect gonadal sex differentiation

Authors
Filby, A.L., Ortiz-Zarragoitia, M., and Tyler, C.R.
ID
ZDB-PUB-140108-22
Date
2014
Source
Environmental toxicology and chemistry   33(3): 602-5 (Journal)
Registered Authors
Tyler, Charles R.
Keywords
none
MeSH Terms
  • Animals
  • Animals, Genetically Modified/genetics
  • Animals, Genetically Modified/growth & development
  • DEAD-box RNA Helicases/genetics*
  • DEAD-box RNA Helicases/metabolism
  • Estrogens/toxicity*
  • Ethinyl Estradiol/toxicity*
  • Genotype
  • Gonads/drug effects*
  • Gonads/growth & development
  • Green Fluorescent Proteins/genetics*
  • Liver/metabolism
  • Promoter Regions, Genetic
  • Sex Differentiation/drug effects*
  • Vitellogenins/metabolism
  • Water Pollutants, Chemical/toxicity*
  • Zebrafish/genetics
  • Zebrafish/growth & development*
  • Zebrafish Proteins/genetics*
  • Zebrafish Proteins/metabolism
PubMed
24273055 Full text @ Environ. Toxicol. Chem.
Abstract

The vas::egfp transgenic zebrafish (Danio rerio) could significantly enhance studies on the mechanisms by which environmental estrogens disrupt sexual differentiation since the developing gonad can be visualized during early life via fluorescence detection. However, there are methodological challenges regarding dissecting out the gonads in early-life-stage fish and transgene responses to estrogen exposure have not been tested. We exposed vas::egfp transgenic zebrafish and their wild-type siblings to the model estrogen 17α-ethinylestradiol (EE2 ) (0.62 and 3.33 ng/L measured concentrations) during sexual development (20 to 60 days post hatch) and used the egfp fluorescence to identify and dissect single gonads (at 40 days post hatch) to provide sufficient RNA for individual gene expression analyses, retaining the remaining gonad in the body cavity for histological analyses of sex and stage of development. Genotyping confirmed that all transgenic control fish were phenotypically egfp-positive (showed green fluorescence). Interestingly, however, in a few transgenic fish exposed to EE2 there was no phenotypic egfp signal, most notably for the 3.33 ng/L EE2 exposure, and we subsequently found gonadal vasa expression was reduced by this concentration of EE2 . Hepatic vitellogenin expression demonstrated that the vas::egfp and wild-type lines responded to estrogen with an equivalent sensitivity. We conclude that the vas::egfp zebrafish provides an enhanced and practical system for mechanistic studies on the effects of environmentally relevant concentrations of estrogens on gonad development.

Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping