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Communication Dans Un Congrès Année : 2007

Estrogenic signalling in the brain of developing zebrafish

Résumé

It is now well admitted that estrogens have important actions in the development and functioning of the central nervous system through modulation of neural differentiation and cell survival in vitro and in vivo. The classical pathways of estrogenic effects involve nuclear receptors acting as ligand-dependant transcription factors that regulate the expression of target genes either directly, by binding to an estrogen responsive element (ERE), or indirectly through interaction with others transcription factors. While only two estrogen receptors (ER), namely ERα and ERβ have been clearly characterized in mammals, birds and amphibians, two ERβ exist in teleost fish, ERβ1 and ERβ2, resulting from a duplication of the ERβ gene. We have recently shown that aromatase B (AroB, the product of the cyp19b gene) in adult zebrafish is expressed in radial glial cells and is strongly up-regulated by estradiol, an effect that involves ER and an ERE located in the proximal cyp19b promoter. Here, we studied the emergence of estrogen signalling by looking at the spatiotemporal expression of three estradiol receptors and aromatase B using in situ hybridization and quantitative real-time PCR and determining the onset of AroB upregulation by estradiol. Our results show a tissue-specific distribution and a differential spatiotemporal expression of ER mRNA with a significant induction of the expression of the three receptors between 24 and 48hpf. In situ hybridization shows that ERβ1 and ERβ2 are expressed early during development in the neuroendocrine regions, while ERα was not detected in the brain until three weeks pf. Between 24 and 48hpf, the expression of AroB mRNA also strongly increases, but this increase is partly blocked by the pure anti-estrogen ICI 182-780. This pattern suggests a concordance between expression of AroB and ER mRNAs. In accordance with these data, from 48hpf to 130hpf, AroB mRNA up-regulation induced by estradiol is abolished by ICI 182-780. Altogether, these data show that functional ERs are expressed in the brain of zebrafish at 48hpf.
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Dates et versions

hal-00189202 , version 1 (20-11-2007)

Identifiants

  • HAL Id : hal-00189202 , version 1

Citer

Karen Mouriec, Isabelle Anglade, Elisabeth Pellegrini, Marie-Madeleine Guéguen, Jean-Jacques Lareyre, et al.. Estrogenic signalling in the brain of developing zebrafish. 11EME journée scientifique du réseau LARC Neurosciences, Oct 2007, Rennes, France. ⟨hal-00189202⟩
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