FIG. 4.

Lentiviral vector treatments restore amounts of the RyR1 protein and affect the size of differentiated MF cells. (a) Control CF cells, untreated MF cells, or MF cells treated with U7-Ctrl vector or with U7-D+E vector were induced to differentiate for 8 days, and immunolabeled with antibodies against RyR1 and myosin heavy chain (MyHC). A magnification of RyR1 labeling is presented in the insets. Scale bars=20 μm. (b) Width distribution of myotubes. Each myotube was classified in one of the four categories according to its largest measured width (<2 μm, 2–5 μm, 5–8 μm, and >8 μm). The distribution of the myotube population in the four categories is represented for each condition (number of myotubes indicated in (d). (c) Quantification by image analysis of the mean fluorescence intensity of RyR1 staining in myotubes relative to the mean fluorescence intensity of MyHC staining, presented as mean±SEM. The mean fluorescence intensity of MyHC staining is not statistically different between the different conditions. The number of myotubes used for quantification is indicated in each bar of the plot. (d) Mean width of myotubes was calculated and results given in μm as mean±SEM of the number of myotubes indicated in each bar. ***p<0.001, ANOVA analysis followed by Bonferroni multiple comparison test. ANOVA, analysis of variance.