Glucocorticoid receptor (DlGR1) is expressed in pre-larval and larval stages of the teleost fish Dicentrarchus labrax

Abstract

Glucocorticoid hormone receptors (GR), members of the nuclear hormone receptor superfamily, are ligand-dependent transcription factors expressed in various tissues by binding to specific DNA sequences. Since glucocorticoids have a role in maintaining the homeostatic status in fish, we previously cloned and sequenced a GR (DlGR1) of adult Dicentrarchus labrax; we also showed mRNA expression (in situ hybridization) and tissue immunohistochemical localization of DlGR1 in several organs. This work has now been extended to the examination of the expression, tissue distribution, and cytolocalization of DlGR1 in larval developmental stages by similar methods to those used for the adult organs. The riboprobe included the DlGR1 cDNA transcriptional activation domain (1.0-1,300 nucleotide sequence) showing no significant similarity with a known second GR cDNA sequence of sea bass. The antibody was specific for an opportunely selected peptide sequence of the DlGR1 transcriptional domain. In histological sections of brain, head kidney, gills, liver, anterior intestine, and spleen cells, the riboprobe was mainly located in the cell nucleus. The antibody identified DlGR1 in the head kidney, gills, liver, and anterior intestine, mainly located in the cytosol. These results are in agreement with the receptor location in adult tissues. The greater presence of both the transcript and protein of DlGR1 in the late developmental stages suggests an increasing expression of this receptor. The cytolocalization (nuclear-cytosolic) and presumptive roles of DlGR1-containing tissues are discussed.

Ontogenesis of the HPI axis and molecular regulation of the cortisol stress response during early development in Dicentrarchus labrax.

“…Gr2 abundance in embryos is higher than gr 1, and its expression pattern is characterized by an initial elevation in hatch and a second in first feeding followed by a relatively steady expression, thereafter. Previous immunohistochemical and in situ hybridization data also verify the presence of gr2 mRNA transcripts and of the glucocorticoid receptor early in development with increasing expression towards the juvenile stage41. In addition we show, for the first time, the expression profile of mr , crf , 11β-hydroxylase and 11β-hsd2 during the early stages of development.…”

Differential expression patterns and localization of glucocorticoid and mineralocorticoid receptor transcripts in the osmoregulatory organs of tilapia during salinity stress

“…In contrast, a mismatch in the GR gene and protein expression has been recently observed in rainbow trout hepatocytes [39,60]. The ontogenetic studies demonstrated that the hybridization signals and protein of GR1 were detected in the nucleus and cytosol of the brain, gill, liver, headkidney and intestine during the early and late developmental stages of the sea bass Dicentrarchus labrax, which suggests an increasing expression of GR in the developmental stages to perform the glucocorticoid function [12]. Moreover, the presence of GR1, GR2 and MR in the gill, kidney and intestine provides evidences that the corticosteroid receptors may play an essential role in the osmoregulatory and homeostatic processes in tilapia.…”

Spleen immune status is affected after acute handling stress but not regulated by cortisol in Eurasian perch, Perca fluviatilis

“…Nevertheless, the information about CRs implication in fish immunity control is scarce. GRs were detected in leucocytes and spleen [21,22]. LPS treatment or infection with blood parasite induced variations in the GRs mRNA expression in the head kidney phagocytes or in the spleen, supporting GR implication in the immune regulation in gilthead seabream, Sparus aurata and common carp, Cyprinus carpio [23e25].…”