Expression patterns of three estrogen receptor genes during zebrafish (Danio rerio) development: evidence for high expression in neuromasts.
The estrogen receptor (ER) genes encode a group of nuclear enhancer proteins, which are important ligand-activated transcription factors, modulating estrogen-target gene transcription. In this study we analyzed expression patterns of three zebrafish ER genes, esr1, esr2a, and esr2b, during development using whole-mount in situ hybridization. High levels of esr2a and esr2b of maternal origin are inherited and segregated to the blastomers. After the mid-blastula transition, the three genes exhibit similar spatio-temporal patterns of expression. In 24 h postfertilization (hpf) embryos, high levels of esr2a and esr2b and low levels of esr1 mRNAs are detected in the epidermis, pectoral fin buds, hatching gland and, to a lesser extent, developing brain. From 24 hpf onward, the expression of the three genes is down-regulated in the epidermis. By 60 hpf, esr2a mRNA is abundant in mature primary neuromasts of the anterior line system and by 3 days postfertilization (dpf), all mature primary neuromasts in both the anterior and posterior lateral line systems express significant levels of esr2a and esr2b transcripts. Histological sections show a high level of esr2a transcripts in both mechanoreceptive hair cells and supporting cells. The transcripts are still detected after neomycin-induced hair cell death, consistent with the presence of esr2a transcripts in supporting cells. From 6 dpf onward, esr2a and esr2b transcripts are robustly co-expressed in primary neuromasts, branchial arches, pectoral fins, and anal papilla, while slight labeling is observed for esr1 transcripts.
Tingaud-Sequeira
Angèle
A
Laboratoire Génomique et Physiologie des Poissons, UMR 1067 NUAGE INRA-IFREMER, Université Bordeaux 1, Avenue des Facultes, Bat. B2, 33405 Talence cedex, France.
André
Michèle
M
Forgue
Jean
J
Barthe
Christophe
C
Babin
Patrick J
PJ
D000818:Animals; D017931:DNA Primers; D018076:DNA, Complementary / Q000235:genetics; D004625:Embryo, Nonmammalian / Q000378:metabolism; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D006652:Histological Techniques; D017403:In Situ Hybridization; D046569:Neuroepithelial Cells / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015027:Zebrafish / Q000196:embryology* / Q000378:metabolism*
D017931:DNA Primers; D018076:DNA, Complementary; D011960:Receptors, Estrogen