Wnt7a and Fzd7 induce the polarization and migration of myogenic cells. (A) Morphological quantification of triangular polarized C2C12 cells upon Wnt7a stimulation and Fzd7 overexpression. Vehicle (Veh.)-treated cells expressing YFP were set to 100%. Error bars represent means ± SEM; n ≥ 4. *, P < 0.05; **, P < 0.01. n.s., no significant difference. (B) Confocal images showing the localization of Fzd7-YFP and the tubulin cytoskeleton of a C2C12 cell. Bar, 4 µm. (C) Sequences derived from live imaging of C2C12 cells that were transfected with Fzd7-YFP or YFP at the given time points. The arrowheads show peripheral Fzd7-YFP that is dynamically rearranged during cell migration. Bar, 10 µm. (D) Frequency of peripheral Fzd7-YFP accumulation in C2C12 cells when compared with Fzd3-YFP. Fzd7-YFP was set to 100%. Error bars represent means ± SEM; n = 3. **, P < 0.01. (E) Representative images from scratch assays with C2C12 cells. The dashed line represents the border of the scratch wound. Cells that were treated with Wnt7a migrate farther than vehicle-treated cells. Bar, 100 µm. (F) Quantification of C2C12 migration in scratch assays as shown in E. Wnt7a significantly increases migration compared with vehicle. Error bars represent means ± SEM; n = 3. **, P < 0.01. (G) Overexpression of Fzd7-Flag also increases the migration of C2C12 cells in scratch assays when compared with empty vector (EV). Error bars represent means ± SEM; n = 3. **, P < 0.01.