title: Smooth muscle calponin: an unconventional CArG-dependent gene that antagonizes neointimal formation.
abstract: OBJECTIVE
  Smooth muscle calponin (CNN1) contains multiple conserved intronic CArG elements that bind serum response factor and display enhancer activity in vitro. The objectives here were to evaluate these CArG elements for activity in transgenic mice and determine the effect of human CNN1 on injury-induced vascular remodeling.
  
  
  RESULTS
  Mice carrying a lacZ reporter under control of intronic CArG elements in the human CNN1 gene failed to show smooth muscle cell (SMC)-restricted activity. However, deletion of the orthologous sequences in mice abolished endogenous Cnn1 promoter activity, suggesting their necessity for in vivo Cnn1 expression. Mice carrying a 38-kb bacterial artificial chromosome (BAC) harboring the human CNN1 gene displayed SMC- restricted expression of the corresponding CNN1 protein, as measured by immunohistochemistry and Western blotting. Extensive BAC recombineering studies revealed the absolute necessity of a single intronic CArG element for correct SMC-restricted expression of human CNN1. Overexpressing human CNN1 suppressed neointimal formation following arterial injury. Mice with an identical BAC carrying mutations in CArG elements that inhibit human CNN1 expression showed outward remodeling and neointimal formation.
  
  
  CONCLUSIONS
  A single intronic CArG element is necessary but insufficient for proper CNN1 expression in vivo. CNN1 overexpression antagonizes arterial injury-induced neointimal formation.
authors.affiliation: Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, NY 14642, USA.
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Long
authors.forename: Orazio J
authors.initials: OJ
authors.lastname: Slivano
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Cowan
authors.forename: Mary A
authors.initials: MA
authors.lastname: Georger
authors.forename: Ting-Hein
authors.initials: TH
authors.lastname: Lee
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Miano
mesh_terms: D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D002339:Carotid Arteries / Q000378:metabolism / Q000473:pathology; D020212:Carotid Artery Injuries / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002460:Cell Line; D049109:Cell Proliferation; D022202:Chromosomes, Artificial, Bacterial; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D007150:Immunohistochemistry; D007438:Introns; D007763:Lac Operon; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008840:Microfilament Proteins / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000378:metabolism* / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000473:pathology; D011401:Promoter Regions, Genetic; D051381:Rats; D027602:Serum Response Element; D026362:Serum Response Factor / Q000378:metabolism; D014162:Transfection; D017539:Tunica Intima / Q000378:metabolism* / Q000473:pathology; D000096985:Calponins
chemical_list: D002135:Calcium-Binding Proteins; D008156:Luciferases; D008840:Microfilament Proteins; D026362:Serum Response Factor; D000096985:Calponins