Srf loss does not affect myogenic differentiation of SCs. (A) Number of MyoG⁺ cells per myofiber in control and Srf mutant plantaris muscle sections before (SO) and after 1 wk of CH (n = 6–10 muscles from n = 4–6 mice). (B) Percentage of MyoD⁺ cells in control and mutant FACS-sorted SCs cultured in rich medium (D0, MBs) or 1 d after differentiation induction (D1; n = 4). (C) Percentage of MyoG⁺ in control and mutant FACS-sorted SCs cultured in rich medium (D0) or 1 (D1) and 3 (D3) days after differentiation induction (n = 4–5). (D) Immunostaining for MyHC, nuclear staining with DAPI, and F-actin staining with phalloidin on control and mutant cells 3 d after differentiation induction. (E) Percentage of nuclei in MyHC⁺ cells in control and mutant cells 3 d after differentiation induction (n = 5–6). Data are mean ± SEM. **, P < 0.01.