Related Experiment Videos
MyoD prevents cyclinA/cdk2 containing E2F complexes formation in terminally differentiated myocytes
P L Puri1, C Balsano, V L Burgio
1Fondazione A Cesalpino and I Clinica Medica, University of Rome La Sapienza, Roma, Italy.
Oncogene
|March 13, 1997
Summary
Myogenic differentiation involves MyoD and p21, which suppress cell cycle reentry by altering E2F complexes. This prevents proliferating myoblasts from re-entering the cell cycle after differentiation.
Area of Science:
- Cell Biology
- Molecular Biology
- Muscle Development
Background:
- Cell cycle withdrawal during myocyte differentiation is controlled by MyoD and pocket proteins.
- Pocket proteins regulate E2F transcription factors, which control the G1/S-phase transition.
Purpose of the Study:
- To analyze E2F complex composition during C2C12 skeletal muscle cell differentiation.
- To understand the role of MyoD and p21 in cell cycle arrest during myogenesis.
Main Methods:
- Electrophoretic mobility shift assay (EMSA) to study E2F complexes.
- Analysis of C2C12 skeletal muscle cells at different differentiation stages.
- Use of Estrogen Receptor-MyoD (ER-MyoD) chimerae in mouse fibroblasts.
Main Results:
- A shift in E2F complexes occurs during differentiation, with E2F4/pRb2/p130 replacing cyclinA/cdk2 complexes.
- MyoD activation and p21 induction prevent serum-stimulated DNA synthesis in differentiating cells.
- MyoD activation inhibits cyclinA/cdk2 reassociation with E2F4, suppressing E2F activity and cell cycle reentry.
Conclusions:
- MyoD induces permanent cell cycle arrest in myocytes through p21 upregulation.
- Suppression of proliferation-associated cyclin/cdk-containing E2F complexes is a key mechanism for cell cycle arrest.
- Formation of E2F4/pRb2/p130 complexes alone is insufficient to prevent cell cycle reactivation.