Myogenin and MyoD siRNA transfection in terminally differentiated myotubes reactivates cyclin D1 and cyclin E2.

<p>(A) Myoblasts treated with Ara-C and induced to differentiate into multinucleated myotubes were transfected with myogenin, MyoD, Myf6 and Myf5 siRNAs and controls. After transfections, growth medium was added to cells prior to RNA analysis by RT/PCR analysis. Cells transfected with myogenin siRNA revealed reduction at the RNA levels of myogenin, MyoD, Myf6 and increase of cyclinD1, cyclinE2 and Myf5 when compared to controls and untransfected C2C12 cells. Cells transfected with MyoD siRNA revealed reduction of the RNA levels of MyoD and substantial increase of cyclinD1, cyclinE2 and Myf5. Cells transfected with Myf6 siRNA revealed reduction of the RNA levels of Myf6. Cells transfected with Myf5 siRNA revealed reduction of the RNA levels of Myf5 and substantial increase of MyoD. (B) Graphs of the RNA analysis. Values were obtained as ratios of the RNA of interest over GAPDH internal control.