title: Mineralocorticoid receptor mutations differentially affect individual gene expression profiles in pseudohypoaldosteronism type 1.
abstract: BACKGROUND
  Type 1 pseudohypoaldosteronism (PHA1), a primary form of mineralocorticoid resistance, is due to inactivating mutations of the NR3C2 gene, coding for the mineralocorticoid receptor (MR).
  
  
  OBJECTIVE
  The objective of the study was to assess whether different NR3C2 mutations have distinct effects on the pattern of MR-dependent transcriptional regulation of aldosterone-regulated genes.
  
  
  METHODS
  Four MR mutations affecting residues in the ligand binding domain, identified in families with PHA1, were tested. MR proteins generated by site-directed mutagenesis were analyzed for their binding to aldosterone and were transiently transfected into renal cells to explore the functional effects on the transcriptional activity of the receptors by cis-trans-cotransactivation assays and by measuring the induction of endogenous gene transcription.
  
  
  RESULTS
  Binding assays showed very low or absent aldosterone binding for mutants MR(877Pro), MR(848Pro), and MR(947stop) and decreased affinity for aldosterone of MR(843Pro). Compared with wild-type MR, the mutations p.Leu843Pro and p.Leu877Pro displayed half-maximal aldosterone-dependent transactivation of reporter genes driven by mouse mammary tumor virus or glucocorticoid response element-2 dependent promoters, whereas MR(848Pro) and MR(947stop) nearly or completely lost transcriptional activity. Although MR(848Pro) and MR(947stop) were also incapable of inducing aldosterone-dependent gene expression of endogenous sgk1, GILZ, NDRG2, and SCNN1A, MR(843Pro) retained complete transcriptional activity on sgk1 and GILZ gene expression, and MR(877Pro) negatively affected the expression of sgk1, NDRG2, and SCNN1A.
  
  
  CONCLUSIONS
  Our data demonstrate that MR mutations differentially affect individual gene expression in a promoter-dependent manner. Investigation of differential gene expression profiles in PHA1 may allow a better understanding of the molecular substrate of phenotypic variability and to elucidate pathogenic mechanisms underlying the disease.
authors.affiliation: Department of Puericulture and Pediatrics, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto 14040-900, Brazil.
authors.forename: Fábio L
authors.initials: FL
authors.lastname: Fernandes-Rosa
authors.forename: Edwige-Ludiwyne
authors.initials: EL
authors.lastname: Hubert
authors.forename: Jérome
authors.initials: J
authors.lastname: Fagart
authors.forename: Nicolas
authors.initials: N
authors.lastname: Tchitchek
authors.forename: Debora
authors.initials: D
authors.lastname: Gomes
authors.forename: Elodie
authors.initials: E
authors.lastname: Jouanno
authors.forename: Arndt
authors.initials: A
authors.lastname: Benecke
authors.forename: Marie-Edith
authors.initials: ME
authors.lastname: Rafestin-Oblin
authors.forename: Xavier
authors.initials: X
authors.lastname: Jeunemaitre
authors.forename: Sonir R
authors.initials: SR
authors.lastname: Antonini
authors.forename: Maria-Christina
authors.initials: MC
authors.lastname: Zennaro
mesh_terms: D000450:Aldosterone / Q000378:metabolism; D015870:Gene Expression / Q000235:genetics / Q000502:physiology; D020869:Gene Expression Profiling; D006579:Heterozygote; D006801:Humans; D008958:Models, Molecular; D009154:Mutation / Q000235:genetics*; D010375:Pedigree; D010957:Plasmids / Q000235:genetics; D014176:Protein Biosynthesis / Q000235:genetics; D011546:Pseudohypoaldosteronism / Q000235:genetics*; D012313:RNA / Q000096:biosynthesis / Q000302:isolation & purification; D018161:Receptors, Mineralocorticoid / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015533:Transcriptional Activation / Q000235:genetics
chemical_list: D018161:Receptors, Mineralocorticoid; D000450:Aldosterone; D012313:RNA