Fig. 7: Muscle fiber Myc expression strongly impairs muscle structure and function. | Nature Communications

Fig. 7: Muscle fiber Myc expression strongly impairs muscle structure and function.

From: Muscle fiber Myc is dispensable for muscle growth and its forced expression severely perturbs homeostasis

Fig. 7

A Schematic of tamoxifen-inducible, muscle stem cell-specific transgenic Myc expression mouse model and time course of tissue collection after an intramuscular cardiotoxin (CTX) injection. B Muscle mass loss (%) in CON and Pax7-MycTG mice 4 (CON, n = 4; TG, n = 5), 7 (CON, n = 6; TG, n = 4) and 14 (CON, n = 7; TG, n = 5) days after intramuscular CTX injection. C Representative images of eMHC, IIA/X (unstained) and IIB fiber type proportion in TA cross-sections 4, 7 and 14 days after intramuscular CTX injection and the contralateral control muscle (Uninj) and (D) quantification at 14 days (n = 4). E Schematic of HSA-MycTG mouse model and tamoxifen treatment regime. Representative western blots (F) and quantification (G) for Myc, RPS6 and RPS14, normalized to α-actinin (CON, n = 9; TG, n = 7). H Body mass immediately before the first tamoxifen injection and 4 or 10 days later for CON (n = 7) and HSA-MycTG (4 d, n = 11; 10 d, n = 8) mice. I Force frequency curve and fatigue response to repeated 200 Hz stimulations in EDL muscle from CON (n = 10) and HSA-MycTG mice at 4 (n = 6) or 10 d (n = 8) time points. J Representative images of H&E (left) and IgG (right) staining in TA cross-sections of CON and 10 d HSA-MycTG mice. K Muscle mass for CON (n = 14) and 4 d (n = 11) and 10 d (n = 8) HSA-MycTG mice. A, E Created in BioRender. Ruegg, M. (2025) https://BioRender.com/d74q573. Data are presented as mean ± SEM. Two-way ANOVAs (B, D, I, K) and repeated measures ANOVAs (H) with Sidak’s post hoc test or Students t test (G) were used to compare between conditions. *, **, and *** denote a significant difference between groups of P  <  0.05, P  <  0.01, and P  <  0.001, respectively.

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