title: Myocardin is sufficient for a smooth muscle-like contractile phenotype.
abstract: BACKGROUND
  Myocardin (Myocd) is a strong coactivator that binds the serum response factor (SRF) transcription factor over CArG elements embedded within smooth muscle cell (SMC) and cardiac muscle cyto-contractile genes. Here, we sought to ascertain whether Myocd-mediated gene expression confers a structural and physiological cardiac or SMC phenotype.
  
  
  RESULTS
  Adenoviral-mediated expression of Myocd in the BC(3)H1 cell line induces cardiac and SMC genes while suppressing both skeletal muscle markers and cell growth. Immunofluorescence microscopy shows that SRF and a SMC-like cyto-contractile apparatus are elevated with Myocd overexpression. A short hairpin RNA to Srf impairs BC(3)H1 cyto-architecture; however, cotransduction with Myocd results in complete restoration of the cyto-architecture. Electron microscopic studies demonstrate a SMC ultrastructural phenotype with no evidence for cardiac sarcomerogenesis. Biochemical and time-lapsed videomicroscopy assays reveal clear evidence for Myocd-induced SMC-like contraction.
  
  
  CONCLUSIONS
  Myocd is sufficient for the establishment of a SMC-like contractile phenotype.
authors.affiliation: Aab Cardiovascular Research Institute, University of Rochester School of Medicine & Dentistry, 211 Bailey Road, Rochester, New York 14586, USA.
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Long
authors.forename: Robert D
authors.initials: RD
authors.lastname: Bell
authors.forename: William T
authors.initials: WT
authors.lastname: Gerthoffer
authors.forename: Berislav V
authors.initials: BV
authors.lastname: Zlokovic
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Miano
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D045744:Cell Line, Tumor; D006801:Humans; D051379:Mice; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D032389:Myocytes, Smooth Muscle / Q000502:physiology*; D009389:Neovascularization, Pathologic / Q000503:physiopathology; D009687:Nuclear Proteins / Q000502:physiology*; D015534:Trans-Activators / Q000502:physiology*; D000099251:Myocardin
chemical_list: D009687:Nuclear Proteins; D015534:Trans-Activators; D000099251:Myocardin