title: Identification and functional analyses of molecular haplotypes of the human osteoprotegerin gene promoter.
abstract: OBJECTIVE
  Osteoprotegerin (OPG) has been reported to be involved in the development of atherosclerotic disease, and OPG gene variation has been associated with plasma OPG levels and different cardiovascular disease phenotypes. However, the genetic architecture of the OPG promoter and its transcriptional regulation are poorly characterized.
  
  
  RESULTS
  We identified 1008 bp of the OPG 5'-flanking region to be sufficiently transcriptionally active in osteosarcoma cell lines and generated serial promoter deletion constructs. Individual subcloning revealed the existence of 3 molecular haplotypes (MolHaps): [T(-960)-A(-946)-G(-900)-T(-864); MolHap1, wild type], [T(-960)-G(-946)-G(-900)-T(-864); MolHap2], [C(-960)-G(-946)-A(-900)-G(-864); MolHap4]. Compared to MolHap1, transcriptional activities of MolHaps 2 and 4 were significantly reduced (P=0.0018). Whereas introduction of the -159C allele reduced transcriptional activities of the full-length constructs (P=0.0014), it significantly increased activities of the deletion constructs (P=0.0005). Electrophoretic mobility shift, competition, and chromatin immunoprecipitation assays revealed specific DNA:protein interactions for the MolHaps with Sp1 and NF-1, and identified Egr1 interacting exclusively with the -159T allele.
  
  
  CONCLUSIONS
  We propose new structural and transcriptional features within the OPG promoter region and identified MolHaps being differentially transcriptionally active and allele-dependently interacting with a proximal polymorphic site.
authors: Leibniz-Institute for Arteriosclerosis Research, University of Münster, Münster, Germany.
authors: Claudia
authors: C
authors: Hagedorn
authors: Ralph
authors: R
authors: Telgmann
authors: Corinna
authors: C
authors: Dördelmann
authors: Boris
authors: B
authors: Schmitz
authors: Sandra
authors: S
authors: Hasenkamp
authors: François
authors: F
authors: Cambien
authors: Martin
authors: M
authors: Paul
authors: Eva
authors: E
authors: Brand
authors: Stefan-Martin
authors: SM
authors: Brand-Herrmann
mesh_terms: D001665:Binding Sites; D045744:Cell Line, Tumor; D024202:Electrophoretic Mobility Shift Assay; D006239:Haplotypes; D006801:Humans; D025542:Neurofibromin 1 / Q000378:metabolism; D053244:Osteoprotegerin / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D016329:Sp1 Transcription Factor / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D025542:Neurofibromin 1; D053244:Osteoprotegerin; D012333:RNA, Messenger; D016329:Sp1 Transcription Factor