Fig. 4.

FGFR4-transduced myoblasts retain the ability to terminally differentiate. a Myoblasts immunolabeled with myosin heavy chain (MyHC), counterstained with DAPI, and visualized with fluorescence microscopy illustrated varying patterns and levels of terminal differentiation. Scale bar represents 100 μm. b Differentiation was similar among most myoblast populations, with the exception of M25. FGFR4^N535K, which had significantly reduced percentage of differentiation compared to parental Myo25. Bars represent mean ± SD. c Myoblast lysates were collected and immunoblotted to demonstrate the presence of MyHC. After 5 days of differentiation, MyHC immunopositivity can be seen in all myoblast lysates except M25.FGFR4^N535K. d Schema illustrating the sequential activation of myogenic regulatory factors as myogenic precursor cells differentiate into mature muscle fibers. e cDNA was generated from myoblasts collected after 0 (MGM) or following 1, 3, or 5 day differentiation and used to measure the gene expression of Pax3, Pax7, Myf5, Myod1, Myogenin, and Myf6. Graphs show representative results from one of three biological replicates. Each experiment consisted of technical triplicates. Statistical significance was analyzed by one-way ANOVA with Tukey’s multiple comparisons test (*p < 0.001) compared to Myo25 at the same time point. Asterisk color represents significance for the corresponding myoblasts