ZFIN ID: ZDB-PUB-170301-9
Functional analysis reveals no transcriptional role for the glucocorticoid receptor β-isoform in zebrafish
Chatzopoulou, A., Schoonheim, P.J., Torraca, V., Meijer, A.H., Spaink, H.P., Schaaf, M.J.
Date: 2017
Source: Molecular and Cellular Endocrinology   447: 61-70 (Journal)
Registered Authors: Meijer, Annemarie H., Schaaf, Marcel J. M., Schoonheim, Peter, Spaink, Herman P., Torraca, Vincenzo
Keywords: Beta-isoform, Corticosteroid, Glucocorticoid receptor, Microarray, Transcriptome analysis, Zebrafish
Microarrays: GEO:GSE84906
MeSH Terms:
  • Animals
  • Animals, Genetically Modified
  • COS Cells
  • Cell Line
  • Chlorocebus aethiops
  • Embryo, Nonmammalian/metabolism
  • Gene Ontology
  • Genes, Dominant
  • Green Fluorescent Proteins/metabolism
  • Luciferases/metabolism
  • Protein Isoforms/metabolism
  • Receptors, Glucocorticoid/metabolism*
  • Transcription, Genetic*
  • Transcriptional Activation/genetics
  • Zebrafish/embryology
  • Zebrafish/genetics*
PubMed: 28242321 Full text @ Mol. Cell. Endocrinol.
In humans, two splice variants of the glucocorticoid receptor (GR) exist: the canonical α-isoform, and the β-isoform, which has been shown to have a dominant-negative effect on hGRα. Previously, we have established the occurrence of a GR β-isoform in zebrafish, and in the present study we have investigated the functional role of the zebrafish GRβ (zGRβ). Reporter assays in COS-1 cells demonstrated a dominant-negative effect of zGRβ but no such effect was observed in zebrafish PAC2 cells using induction of the fk506 binding protein 5 (fkbp5) gene as readout. Subsequently, we generated a transgenic fish line with inducible expression of zGRβ. Transcriptome analysis suggested transcriptional regulation of genes by zGRβ in this line, but further validation failed to confirm this role. Based on these results, its low expression level and its poor evolutionary conservation, we suggest that the zebrafish GR β-isoform does not have a functional role in transcriptional regulation.