(M) FACS-isolated SCs were cultured for 2 days in proliferation medium followed by 2 days in differentiation medium; the degree of differentiation was assessed by IF staining of MF20+. Scale bar = 100 µm. Quantifications of the numbers of MF20+ area per nucleus are shown on the right (n=3 mice, each). Error bars represent s.d.'s of the mean. Student's t-test (two-sided): *P<0.05, **P<0.01, ***P<0.001. 