title: Interaction between the trout mineralocorticoid and glucocorticoid receptors in vitro.
abstract: The salmonid corticosteroid receptors (CRs), glucocorticoid receptors 1 and 2 (GR1 and GR2) and the mineralocorticoid receptor (MR) share a high degree of homology with regard to structure, ligand- and DNA response element-binding, and cellular co-localization. Typically, these nuclear hormone receptors homodimerize to confer transcriptional activation of target genes, but a few studies using mammalian receptors suggest some degree of heterodimerization. We observed that the trout MR confers a several fold lower transcriptional activity compared to the trout GRs. This made us question the functional relevance of the MR when this receptor is located in the same cells as the GRs and activated by cortisol. A series of co-transfection experiments using different glucocorticoid response elements (GREs) containing promoter-reporter constructs were carried out to investigate any possible interaction between the piscine CRs. Co-transfection of the GRs with the MR significantly reduced the total transcriptional activity even at low MR levels, suggesting interaction between these receptors. Co-transfection of GR1 or GR2 with the MR did not affect the subcellular localization of the GRs, and the MR-mediated inhibition seemed to be independent of specific activation or inhibition of the MR. Site-directed mutagenesis of the DNA-binding domain and dimerization interface of the MR showed that the inhibition was dependent on DNA binding but not necessarily on dimerization ability. Thus, we suggest that the interaction between MR and the GRs may regulate the cortisol response in cell types where the receptors co-localize and propose a dominant-negative role for the MR in cortisol-mediated transcriptional activity.
authors.affiliation: INRAUR1037 Fish Physiology and Genomics, Campus de Beaulieu, 35000 Rennes, FranceCNRS UMR5239Université de Lyon 1, ENS de Lyon, 69364 Lyon Cedex, FranceDepartment of BiologyCenter for Advanced Bioimaging (CAB), University of Copenhagen, Copenhagen, DenmarkInsermU1185, Faculté de Médecine Paris-Sud, Université de Paris-Sud, 94276 Le Kremlin-Bicêtre, France pkiilerich@bio.ku.dk prunet@rennes.inra.fr.
authors.forename: Pia
authors.initials: P
authors.lastname: Kiilerich
authors.affiliation: INRAUR1037 Fish Physiology and Genomics, Campus de Beaulieu, 35000 Rennes, FranceCNRS UMR5239Université de Lyon 1, ENS de Lyon, 69364 Lyon Cedex, FranceDepartment of BiologyCenter for Advanced Bioimaging (CAB), University of Copenhagen, Copenhagen, DenmarkInsermU1185, Faculté de Médecine Paris-Sud, Université de Paris-Sud, 94276 Le Kremlin-Bicêtre, France.
authors.forename: Gérard
authors.initials: G
authors.lastname: Triqueneaux
authors.affiliation: INRAUR1037 Fish Physiology and Genomics, Campus de Beaulieu, 35000 Rennes, FranceCNRS UMR5239Université de Lyon 1, ENS de Lyon, 69364 Lyon Cedex, FranceDepartment of BiologyCenter for Advanced Bioimaging (CAB), University of Copenhagen, Copenhagen, DenmarkInsermU1185, Faculté de Médecine Paris-Sud, Université de Paris-Sud, 94276 Le Kremlin-Bicêtre, France.
authors.forename: Nynne Meyn
authors.initials: NM
authors.lastname: Christensen
authors.affiliation: INRAUR1037 Fish Physiology and Genomics, Campus de Beaulieu, 35000 Rennes, FranceCNRS UMR5239Université de Lyon 1, ENS de Lyon, 69364 Lyon Cedex, FranceDepartment of BiologyCenter for Advanced Bioimaging (CAB), University of Copenhagen, Copenhagen, DenmarkInsermU1185, Faculté de Médecine Paris-Sud, Université de Paris-Sud, 94276 Le Kremlin-Bicêtre, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Trayer
authors.affiliation: INRAUR1037 Fish Physiology and Genomics, Campus de Beaulieu, 35000 Rennes, FranceCNRS UMR5239Université de Lyon 1, ENS de Lyon, 69364 Lyon Cedex, FranceDepartment of BiologyCenter for Advanced Bioimaging (CAB), University of Copenhagen, Copenhagen, DenmarkInsermU1185, Faculté de Médecine Paris-Sud, Université de Paris-Sud, 94276 Le Kremlin-Bicêtre, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Terrien
authors.affiliation: INRAUR1037 Fish Physiology and Genomics, Campus de Beaulieu, 35000 Rennes, FranceCNRS UMR5239Université de Lyon 1, ENS de Lyon, 69364 Lyon Cedex, FranceDepartment of BiologyCenter for Advanced Bioimaging (CAB), University of Copenhagen, Copenhagen, DenmarkInsermU1185, Faculté de Médecine Paris-Sud, Université de Paris-Sud, 94276 Le Kremlin-Bicêtre, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Lombès
authors.affiliation: INRAUR1037 Fish Physiology and Genomics, Campus de Beaulieu, 35000 Rennes, FranceCNRS UMR5239Université de Lyon 1, ENS de Lyon, 69364 Lyon Cedex, FranceDepartment of BiologyCenter for Advanced Bioimaging (CAB), University of Copenhagen, Copenhagen, DenmarkInsermU1185, Faculté de Médecine Paris-Sud, Université de Paris-Sud, 94276 Le Kremlin-Bicêtre, France pkiilerich@bio.ku.dk prunet@rennes.inra.fr.
authors.forename: Patrick
authors.initials: P
authors.lastname: Prunet
mesh_terms: D000818:Animals; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005938:Glucocorticoids / Q000235:genetics / Q000378:metabolism; D006854:Hydrocortisone / Q000235:genetics / Q000378:metabolism; D008901:Mineralocorticoids / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed / Q000379:methods; D011401:Promoter Regions, Genetic / Q000235:genetics; D011965:Receptors, Glucocorticoid / Q000235:genetics / Q000378:metabolism*; D018161:Receptors, Mineralocorticoid / Q000235:genetics / Q000378:metabolism; D011987:Receptors, Steroid / Q000235:genetics / Q000378:metabolism; D020218:Response Elements / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics; D015533:Transcriptional Activation / Q000235:genetics; D014162:Transfection / Q000379:methods; D014337:Trout / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D005938:Glucocorticoids; D008901:Mineralocorticoids; D011965:Receptors, Glucocorticoid; D018161:Receptors, Mineralocorticoid; D011987:Receptors, Steroid; D006854:Hydrocortisone
keywords: dominant-negative; glucocorticoid receptor; heterodimerization; interaction; mineralocorticoid receptor; trout