Related Experiment Videos
Intimate relationship between TGF-beta/BMP signaling and runt domain transcription factor, PEBP2/CBF
1Department of Biochemistry, School of Medicine, and Medical Research Institute, Chungbuk National University, Cheongju, Korea.
Background:
When C2C12 pluripotent mesenchymal precursor cells are treated with transforming growth factor-beta1 (TGF-beta1), terminal differentiation into myotubes is blocked. Treatment with bone morphogenetic protein-2 (BMP-2) not only blocks myogenic differentiation but also induces osteoblastic differentiation. However, the molecular mechanisms governing the ability of TGF-beta and BMP to induce ligand-specific responses and inhibit myogenic differentiation are not known. The objective of our studies was to elucidate the molecular mechanisms that block myoblastic differentiation and induce osteoblastic differentiation in C2C12 cells.
Methods:
Induction of RUNX2/PEBP2alphaA/Cbfa1 by TGF-beta and BMP was examined by electrophoretic mobility shift assay (EMSA) and Northern blot analysis. C2C12 cells stably expressing RUNX2 or Smad, or both, were established, and the role of these genes in the process of osteoblastic differentiation was analyzed by examining the expression of osteoblast-specific markers.
Results:
Treatment of C2C12 with TGF-beta and BMP-induced RUNX2/PEBP2alphaA/Cbfa1, a global regulator of osteogenesis. Cooperation between RUNX2 and BMP-activated Smad induced osteoblastic differentiation.
Conclusions:
Both TGF-beta and BMP activate transcription of RUNX2, which is sufficient to inhibit myogenesis. To induce osteogenesis, BMP-induced RUNX2 must cooperate with BMP-activated Smads.
Insights
Transforming growth factor-beta1 (TGF-beta1) and bone morphogenetic protein-2 (BMP-2) block muscle cell differentiation. Both activate RUNX2, inhibiting myogenesis, but only BMP-2 with Smad induces bone cell differentiation.
Area of Science:
- Cell biology
- Molecular biology
- Developmental biology
Background:
- C2C12 cells differentiate into myotubes when untreated.
- Transforming growth factor-beta1 (TGF-beta1) blocks myotube differentiation.
- Bone morphogenetic protein-2 (BMP-2) blocks myotube differentiation and induces osteoblastic differentiation.
Purpose of the Study:
- Elucidate molecular mechanisms of TGF-beta1 and BMP-2.
- Investigate how these factors induce ligand-specific responses.
- Determine how they inhibit myogenic differentiation.
Main Methods:
- Electrophoretic mobility shift assay (EMSA) and Northern blot analysis.
- Stable C2C12 cell lines expressing RUNX2 or Smad.
- Analysis of osteoblast-specific marker expression.
Main Results:
- TGF-beta1 and BMP-2 induce RUNX2/PEBP2alphaA/Cbfa1, a key regulator of osteogenesis.
- RUNX2 cooperates with BMP-activated Smad to induce osteoblastic differentiation.
Conclusions:
- Both TGF-beta1 and BMP-2 activate RUNX2 transcription, inhibiting myogenesis.
- BMP-2 requires cooperation with BMP-activated Smads to induce osteogenesis.