Identification of estrogen target genes during zebrafish embryonic development through transcriptomic analysis.
Estrogen signaling is important for vertebrate embryonic development. Here we have used zebrafish (Danio rerio) as a vertebrate model to analyze estrogen signaling during development. Zebrafish embryos were exposed to 1 µM 17β-estradiol (E2) or vehicle from 3 hours to 4 days post fertilization (dpf), harvested at 1, 2, 3 and 4 dpf, and subjected to RNA extraction for transcriptome analysis using microarrays. Differentially expressed genes by E2-treatment were analyzed with hierarchical clustering followed by biological process and tissue enrichment analysis. Markedly distinct sets of genes were up and down-regulated by E2 at the four different time points. Among these genes, only the well-known estrogenic marker vtg1 was co-regulated at all time points. Despite this, the biological functional categories targeted by E2 were relatively similar throughout zebrafish development. According to knowledge-based tissue enrichment, estrogen responsive genes were clustered mainly in the liver, pancreas and brain. This was in line with the developmental dynamics of estrogen-target tissues that were visualized using transgenic zebrafish containing estrogen responsive elements driving the expression of GFP (Tg(5xERE:GFP)). Finally, the identified embryonic estrogen-responsive genes were compared to already published estrogen-responsive genes identified in male adult zebrafish (Gene Expression Omnibus database). The expressions of a few genes were co-regulated by E2 in both embryonic and adult zebrafish. These could potentially be used as estrogenic biomarkers for exposure to estrogens or estrogenic endocrine disruptors in zebrafish. In conclusion, our data suggests that estrogen effects on early embryonic zebrafish development are stage- and tissue- specific.
Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America.
Ruixin
R
Hao
Maria
M
Bondesson
Amar V
AV
Singh
Anne
A
Riu
Catherine W
CW
McCollum
Thomas B
TB
Knudsen
Daniel A
DA
Gorelick
Jan-Åke
JÅ
Gustafsson
D000818:Animals; D030801:Animals, Genetically Modified; D016000:Cluster Analysis; D004305:Dose-Response Relationship, Drug; D004625:Embryo, Nonmammalian / Q000187:drug effects / Q000196:embryology / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology*; D047628:Estrogen Receptor alpha / Q000235:genetics; D004967:Estrogens / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D063990:Gene Ontology; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D017403:In Situ Hybridization; D008297:Male; D008856:Microscopy, Fluorescence; D020411:Oligonucleotide Array Sequence Analysis; D025341:Principal Component Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D059467:Transcriptome / Q000187:drug effects*; D015027:Zebrafish / Q000196:embryology / Q000235:genetics* / Q000254:growth & development; D029961:Zebrafish Proteins / Q000235:genetics
D047628:Estrogen Receptor alpha; D004967:Estrogens; D029961:Zebrafish Proteins; D049452:Green Fluorescent Proteins; D004958:Estradiol