For myoblast culture and transplantation, satellite cells were FACS purified from Pax7-zsGreen mice through gating for zsGreen and Hoechst using a cell sorter (MoFlo XDP, Beckman Coulter; Bentzinger et al., 2013b (link)). To derive primary myoblasts, the cells were then plated on collagen-coated dishes (BD) in Ham’s F10 medium supplemented with 20% FBS and 5 ng/ml of basic FGF (EMD Millipore). C2C12 cells and human myoblasts were cultured in DMEM supplemented with 10% FBS (von Maltzahn et al., 2012 (link)). For in vitro morphology quantifications, Wnt7a was used at a concentration of 50 ng/ml.