Fig. 3

MuSC depletion due to increased population of differentiating myoblasts in 4-week-old Mll4^ΔMCK muscles. (A) Pax7⁺ MuSC number per 100 fibers was quantified in TA muscles of 0, 2, 4, and 8-week-old Mll4^ΔMCK and littermate control mice. Immunohistochemistry on TA (B) and soleus (C) muscle section with DAPI (blue), anti-laminin (green), and anti-Pax7 (red). Scale bars, 20 μm. (D) Pax7⁺ MuSC number per 100 fibers was quantified in soleus muscles of 4 and 8-week-old Mll4^ΔMCK and littermate control mice. (E) Immunohistochemistry on 4 W TA muscle section with DAPI (blue), anti-Ki67 (green), and anti-Pax7 (red). Scale bars, 20 μm. (F) Pax7⁺Ki67⁺ cell number per total Pax7⁺ cells of 4 W TA muscle. (G) Immunocytochemistry of sorted MuSCs with DAPI (blue), anti-Pax7 (red), anti-MyoD (green), and EdU (white – pseudo color for Alexa Fluor 647). MyoD⁺ cells and EdU⁺ cells are marked with arrowheads and sharps, respectively. Scale bars, 20 μm. For enlarged images, Scale bars represent 10 μm. (H) MyoD⁺ cell number per total Pax7⁺ cells. (I) Schematic diagram of EdU treatment. (J) MyoD⁺ cell number per EdU⁺Pax7⁺ cells. (A, D, F) n = 3–4 mice for each genotype. (H, J) n = 3–4 mice for each genotype; >200 sorted MuSCs per mouse were quantified. (A, D, F, H, J) Data are presented as mean ± SEM of biological replicates. Statistical analyses were performed using unpaired t-test with Welch’s correction