Identification of a BMP-responsive element in Id1, the gene for inhibition of myogenesis.
BACKGROUND
Bone morphogenetic protein-2 (BMP-2) stimulates osteoblast differentiation, but inhibits myogenic differentiation in C2C12 myoblasts. BMP-2 induces transcription of Id1, an inhibitor for myogenesis, within 1 h in the cells. To examine the molecular mechanism of the action of BMP-2, we analysed a BMP-2-responsive element (BRE) in the 5' flanking region of the human Id1 gene.


RESULTS
A GC-rich region between -985 bp and -957 bp of the human Id1 gene was identified as a BRE. The BRE containing promoter activity was stimulated by BMP-2 or by constitutively active BMP receptors (BMPR-IA and BMPR-IB). The stimulation was blocked by co-transfecting with dominant negative BMPR-IA or Smad7. A unique DNA-protein complex was induced in response to BMP-2 on the BRE. The complex induced by BMP-2 contained Smad1 and Smad4, possibly as a complex of both Smads. BMP-2 failed to stimulate the expression of Id1 mRNA in Smad4-deficient cells. Over-expression of Smad4, but not Smad1, stimulated the Id1 reporter activity and the expression of endogenous Id1 mRNA in Smad4-deficient cells.


CONCLUSIONS
Signalling of BMP-2 to stimulate the expression of Id1 would be transduced by BMPR-IA and mediated by Smad1 and Smad4, both of which form a complex on the 29 bp GC-rich element.
Katagiri
Takenobu
T
Department of Biochemistry, School of Dentistry, Showa University, Tokyo, Japan. katagiri@dent.showa-u.ac.jp
Imada
Mana
M
Yanai
Takeshi
T
Suda
Tatsuo
T
Takahashi
Naoyuki
N
Kamijo
Ryutaro
R
D000818:Animals; D055396:Bone Morphogenetic Protein 2; D052005:Bone Morphogenetic Protein Receptors, Type I; D019485:Bone Morphogenetic Proteins / Q000378:metabolism*; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism; D017930:Genes, Reporter; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D051798:Inhibitor of Differentiation Protein 1; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D017978:Receptors, Growth Factor / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins; D020218:Response Elements / Q000235:genetics*; D015398:Signal Transduction / Q000502:physiology*; D051785:Smad Proteins; D051898:Smad1 Protein; D051901:Smad4 Protein; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D016212:Transforming Growth Factor beta
C525718:BMP2 protein, human; C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; C497453:ID1 protein, human; C497455:Idb1 protein, mouse; D051798:Inhibitor of Differentiation Protein 1; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017978:Receptors, Growth Factor; D012097:Repressor Proteins; C497399:SMAD1 protein, human; C497796:SMAD4 protein, human; D051785:Smad Proteins; D051898:Smad1 Protein; C497401:Smad1 protein, mouse; D051901:Smad4 Protein; C490810:Smad4 protein, mouse; D015534:Trans-Activators; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D017346:Protein Serine-Threonine Kinases; D020928:Mitogen-Activated Protein Kinases; C498211:BMPR1A protein, human; C498214:BMPR1B protein, human; C498212:Bmpr1a protein, mouse; C498215:Bmpr1b protein, mouse; D052005:Bone Morphogenetic Protein Receptors, Type I