Developmental regulation of collagenase-3 mRNA in normal, differentiating osteoblasts through the activator protein-1 and the runt domain binding sites.
Collagenase-3 mRNA is initially detectable when osteoblasts cease proliferation, increasing during differentiation and mineralization. We showed that this developmental expression is due to an increase in collagenase-3 gene transcription. Mutation of either the activator protein-1 or the runt domain binding site decreased collagenase-3 promoter activity, demonstrating that these sites are responsible for collagenase-3 gene transcription. The activator protein-1 and runt domain binding sites bind members of the activator protein-1 and core-binding factor family of transcription factors, respectively. We identified core-binding factor a1 binding to the runt domain binding site and JunD in addition to a Fos-related antigen binding to the activator protein-1 site. Overexpression of both c-Fos and c-Jun in osteoblasts or core-binding factor a1 increased collagenase-3 promoter activity. Furthermore, overexpression of c-Fos, c-Jun, and core-binding factor a1 synergistically increased collagenase-3 promoter activity. Mutation of either the activator protein-1 or the runt domain binding site resulted in the inability of c-Fos and c-Jun or core-binding factor a1 to increase collagenase-3 promoter activity, suggesting that there is cooperative interaction between the sites and the proteins. Overexpression of Fra-2 and JunD repressed core-binding factor a1-induced collagenase-3 promoter activity. Our results suggest that members of the activator protein-1 and core-binding factor families, binding to the activator protein-1 and runt domain binding sites are responsible for the developmental regulation of collagenase-3 gene expression in osteoblasts.
Winchester
S K
SK
Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, Missouri 63104, USA.
Selvamurugan
N
N
D'Alonzo
R C
RC
Partridge
N C
NC
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002454:Cell Differentiation; D017364:Collagenases / Q000235:genetics*; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000378:metabolism*; D029721:Drosophila Proteins; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D053509:Matrix Metalloproteinase 13; D009687:Nuclear Proteins; D010006:Osteoblasts / Q000166:cytology / Q000201:enzymology*; D011401:Promoter Regions, Genetic; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014157:Transcription Factors
D017931:DNA Primers; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D009687:Nuclear Proteins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D014157:Transcription Factors; C080833:run protein, Drosophila; D017364:Collagenases; D053509:Matrix Metalloproteinase 13; C507083:Mmp13 protein, rat