Fig. 8: Muscle fiber Myc overexpression promotes growth-related gene expression signatures, but even a minority of Myc overexpressing fibers impairs muscle regrowth after nerve injury. | Nature Communications

Fig. 8: Muscle fiber Myc overexpression promotes growth-related gene expression signatures, but even a minority of Myc overexpressing fibers impairs muscle regrowth after nerve injury.

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

Fig. 8

A Principle component analysis of mRNAseq data generated from GAS muscle of male CON and HSA-MycTG mice 4 (CON, n = 3; TG, n = 4) or 10 (n = 4) days after the first of 5 tamoxifen injections. 4 d and 10 d CON group samples were pooled. B Overlap of differentially expressed genes (FDR < 0.05; LFC > 0.5) between CON and either 4 d or 10 d HSA-MycTG groups and C Scatterplot of log-fold change and –log10 FDR between CON and 4 d HSA-MycTG for all detected ribosomal protein genes. D Pairwise Venn diagram comparisons of genes differentially expressed for acute (3 d AktTG and 4 d HSA-MycTG) and chronic (14 d AktTG and 10 d HSA-MycTG) activation of AKT and overexpression of Myc. Tan (MycTG) and lilac (AktTG) colored arrows indicate direction of change. E Gene ontology (Biological process) terms associated with overlapping genes between 14 d AktTG and 10 d HSA-MycTG (D, right). F Lineage tracing approach to track MuSC-myofiber fusion events following sciatic nerve crush in Pax7-MycTG mice. G Representative images and quantification of eGFP+ fiber number (H) in TA muscle cross-sections 28 d after nerve crush in Pax7-eGFP (n = 3), and Pax7-MycTG (n = 4) mice and in contralateral TA muscles from Pax7-MycTG. White arrowhead indicates an eGFP+ MuSC (eGFP image intensity increased compared to fibers). Fiber size distribution of eGFP+ and eGFP- muscle fibers 28 d after nerve crush in TA muscle from (I) Pax7-eGFP (n = 3) and (J) Pax7-MycTG (n = 4) mice. K Representative image of eGFP+ fibers in longitudinal sections from Pax7-MycTG mice 28 d after nerve crush. L Muscle mass 28 days after sciatic nerve crush normalized to the innervated contralateral limb in control (CON, n = 14) and Pax7-MycTG (n = 13) mice. M In vitro specific force in EDL muscles 28 d after nerve crush (and innervated contralateral) in CON (Inn, n = 13; 28 d, n = 14) and Pax7-MycTG (n = 13) mice. F Created in BioRender. Ruegg, M. (2025) https://BioRender.com/d74q573. Data are mean ± SEM. Two tailed, independent (I, J) and paired (H) Student’s t tests, two-way repeated measures (L) or two-way ANOVAs with Sidak’s post hoc test (M) were used to compare between conditions. For (B–D), P values were adjusted for multiple comparisons using the Benjamini-Hochberg (FDR) procedure. *, **, and *** denote a significant difference between groups of P  <  0.05, P  <  0.01, and P  <  0.001, respectively.

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