Fig. 2

DUX4c overexpression induces the formation of disorganized myotubes with large nuclear clusters. Healthy primary myoblasts were transfected with pAC1M2-DUX4c and differentiated 48 h later. After the first myotubes formed (day 3), DUX4c expression was induced by the addition of 100 ng or 1 μg of doxycycline to the culture medium. At day 8, myotubes were fixed, and DUX4c (red) and troponin T (green) were immunodetected. Nuclei were labeled with DAPI. A cluster of nuclei (> 5 nuclei) without endogenous DUX4c labeling is boxed (0 ng Dox). Clusters of nuclei presenting a ring-like structure are circled. Stars indicate cytoplasmic DUX4c partially co-localizing with troponin T. Scale bar: 30 μm