Delayed cell cycle withdrawal and differentiation in Brag2- and Dock180-deficient myoblasts. (A) Merged laser-scanning confocal image of representative fields of Cnt2Si and DKD myoblasts after 24 h in DM, labeled for BrdU (green) and with To-Pro (blue). BrdU⁺ nuclei are colored in teal in the merged image. Bar, 100 μm. (B) BrdU incorporation for each stable cell line after 24 h in DM and a 6-h BrdU incubation. (*P < 0.001). (C) Immunofluorescence of representative image fields of Cnt2Si and DKD myoblasts after 72 h in DM, labeled for myogenin (red), MHC (green), and with Hoechst 33258 (blue). Bar, 50 μm. (D) Differentiation as measured by myogenin (*, P < 0.0006) and MHC (**, P < 0.003; ***, P < 0.03) expression for each stable cell line after 72 h in DM. In all cases, error bars indicate the mean ± SE of three independent determinations, in which a minimum of 1,000 nuclei were counted per trial.