Fig 3.

Activated caspase 3 induces differentiation in growing myoblasts. (A) Subconfluent C2C12 myoblasts were transfected with 20 pg of active caspase 3 protein and examined after 12 h for the presence of myosin heavy chain (anti-MF20) detected by using a FITC-conjugated secondary antibody. A confluent population of cells were incubated in low-serum media (differentiation media) to induce myoblast differentiation and examined after 12 h. In all cells examined, nuclei were localized with DAPI staining. Figure is representative of seven trials. (B) Caspase 3 activity results in a withdrawal of cells from the cell cycle. A subconfluent population of cells maintained in growth media was transfected with 20 pg of active caspase 3 protein. Cells were fixed after 24–28 h and stained for the cell proliferation marker cyclin D1 (FITC-labeled) and active caspase 3 (Alexa 594). Cells containing active caspase 3 do not express cyclin D1. Total nuclei are shown stained with DAPI. Figure is representative of five trials.