Fig. 1. Non-apoptotic morphology of adherent C2C12 cells and caspase-3 activity in the adherent cells. C2C12 cells were induced to differentiate over a 5-day time course. (A) DAPI-stained nuclear morphology of adherent and detached C2C12 cells after 2 days of differentiation. (B) Caspase-3-like activity was assayed using the fluorogenic substrate DEVD-afc over a 5-day differentiation period. Enzyme activity is expressed as an increase in arbitrary fluorescent units per minute per milligram of protein (AFU/min/mg). The histogram shows the mean ± s.d. of three independent experiments. (C) Immunoblot for caspase-3 processing over a 5-day differentiation period. Staurosporine-treated (1 µM for 4 hours) C2C12 cells (+ve) were used as a positive control for caspase-3 cleavage.