title: Aldosterone alters the chromatin structure of the murine endothelin-1 gene.
abstract: Aldosterone increases sodium reabsorption in the renal collecting duct and systemic blood pressure. Paradoxically, aldosterone also induces transcription of the endothelin-1 (Edn1) gene to increase protein (ET-1) levels, which inhibits sodium reabsorption.
  
  
  OBJECTIVE
  Here we investigated changes in the chromatin structure of the Edn1 gene of collecting duct cell lines in response to aldosterone treatment. The Edn1 gene has a CpG island that encompasses the transcription start site and four sites in the 5' regulatory region previously linked to transcriptional regulation.
  
  
  METHODS
  The chromatin structure of the Edn1 gene was investigated using a quantitative PCR-based DNaseI hypersensitivity assay in murine hepatocyte (AML12), renal cortical collecting duct (mpkCCDC14), outer medullary collecting duct1 (OMCD1), and inner medullary collecting duct-3 (IMCD-3) cell lines.
  
  
  RESULTS
  The CpG island was uniformly accessible. One calcium-responsive NFAT element remained at low chromatin accessibility in all cell lines under all conditions tested. However, the second calcium responsive NFAT element located at -1563bp upstream became markedly more accessible in IMCD-3 cells exposed to aldosterone. Importantly, one established aldosterone hormone response element HRE at -671bp relative to the transcription start site was highly accessible, and another HRE (-551bp) became more accessible in aldosterone-treated IMCD-3 and OMCD1 cells.
  
  
  CONCLUSIONS
  The evidence supports a model in which aldosterone activation of the mineralocorticoid receptor (MR) results in the MR-hormone complex binding at HRE at -671bp to open chromatin structure around other regulatory elements in the Edn1 gene.
authors.affiliation: North Florida/South Georgia VA Health System, Gainesville, FL 32608, United States; Department of Physiology, University of Florida, Gainesville, FL 32608, United States.
authors.forename: Amanda K
authors.initials: AK
authors.lastname: Welch
authors.affiliation: North Florida/South Georgia VA Health System, Gainesville, FL 32608, United States; Department of Medicine, Division of Nephrology, Hypertension, and Renal Transplantation, University of Florida, Gainesville, FL 32608, United States.
authors.forename: I
authors.initials: I
authors.lastname: Jeanette Lynch
authors.affiliation: Department of Medicine, Division of Nephrology, Hypertension, and Renal Transplantation, University of Florida, Gainesville, FL 32608, United States; Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32608, United States.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Gumz
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32608, United States.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Cain
authors.affiliation: North Florida/South Georgia VA Health System, Gainesville, FL 32608, United States; Department of Medicine, Division of Nephrology, Hypertension, and Renal Transplantation, University of Florida, Gainesville, FL 32608, United States. Electronic address: cswingo@ufl.edu.
authors.forename: Charles S
authors.initials: CS
authors.lastname: Wingo
mesh_terms: D000450:Aldosterone / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D002843:Chromatin / Q000737:chemistry / Q000187:drug effects*; D019332:Endothelin-1 / Q000235:genetics*; D051379:Mice; D011487:Protein Conformation; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D002843:Chromatin; D019332:Endothelin-1; D000450:Aldosterone
keywords: Aldosterone; Chromatin; Chromatin structure; Epigenetics; Kidney