title: Bone morphogenetic protein-2 suppresses collagenase-3 promoter activity in osteoblasts through a runt domain factor 2 binding site.
abstract: Transforming growth factor-beta (TGFbeta) superfamily of growth factors, which include bone morphogenetic proteins (BMPs), have multiple effects in osteoblasts. In this study, we examined the regulation of collagenase-3 promoter activity by BMP-2 in osteoblast-enriched (Ob) cells from fetal rat calvariae. BMP-2 suppressed the activity of a -2 kb collagenase-3 promoter/luciferase recombinant in a time- and dose-dependent manner. The BMP-2 effect on the collagenase-3 promoter was further tested in several collagenase-3 promoter deletion constructs and it was narrowed down to a -148 to -94 nucleotide segment of the promoter containing a runt domain factor 2 (Runx2) site at nucleotide -132 to -126. The effect of BMP-2 was obliterated in a collagenase-3 promoter/luciferase construct containing a mutated Runx2 (mRunx2) sequence indicating that the Runx2 site mediates the BMP-2 response. Electrophoretic mobility shift assays, using nuclear extracts from control and BMP-2-treated Ob cells, indicated that the Runx2 protein is a component of the specific DNA-protein complex formed on the Runx2 site and that the BMP-2 effect may be associated with minor protein modifications rather than major changes in the composition of specific proteins interacting with the Runx2 site. We confirmed that other members of the TGFbeta family can down-regulate the collagenase-3 promoter by showing that TGFbeta1 also suppresses the promoter activity in a time- and dose-dependent manner. In conclusion, this study demonstrates that BMP-2 and TGFbeta1 suppress collagenase-3 promoter activity in osteoblasts and establishes a link between BMP-2 action and collagenase-3 expression via Runx2, a major regulator of osteoblast formation and function.
authors.affiliation: Department of Research, Saint Francis Hospital and Medical Center, Hartford, Connecticut 06105, USA. svarghes@stfranciscare.org
authors.forename: Samuel
authors.initials: S
authors.lastname: Varghese
authors.forename: Sheila
authors.initials: S
authors.lastname: Rydziel
authors.forename: Ernesto
authors.initials: E
authors.lastname: Canalis
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000235:genetics; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D002478:Cells, Cultured; D017364:Collagenases / Q000235:genetics*; D050659:Core Binding Factor Alpha 1 Subunit; D050657:Core Binding Factor alpha Subunits; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D053509:Matrix Metalloproteinase 13; D009363:Neoplasm Proteins / Q000378:metabolism*; D010006:Osteoblasts / Q000201:enzymology*; D011401:Promoter Regions, Genetic / Q000187:drug effects*; D051381:Rats; D012886:Skull / Q000166:cytology; D014157:Transcription Factors / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000008:administration & dosage / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1
chemical_list: C525720:Bmp2 protein, rat; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D050659:Core Binding Factor Alpha 1 Subunit; D050657:Core Binding Factor alpha Subunits; D009363:Neoplasm Proteins; C508962:Tgfb1 protein, rat; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D017364:Collagenases; D053509:Matrix Metalloproteinase 13; C507083:Mmp13 protein, rat