(A) Gene ontology (GO) biological processes associated with downregulated and upregulated genes. (B) Heatmap representing selected genes involved in the regulation of cell proliferation in cultured WT and Fn14-KO myogenic cells generated after analysis of RNA-seq dataset. (C) WT and Fn14-KO myogenic cultures were pulse labeled with EdU for 60 minutes. Representative images of the cultures after detection of EdU and Hoechst staining (nuclei detection). Scale bars: 50 μm. (D) Quantification of percentage of EdU⁺ cells in WT and Fn14-KO cultures. n = 3 biological replicates in each group. (E) TA muscle of Fn14^fl/fl and Fn14^scKO mice was injured by intramuscular injection of 1.2% BaCl₂ solution. After 3 days, the mice were given an intraperitoneal injection of EdU and 11 days later TA muscles were collected and transverse muscle sections were generated and stained to detect EdU, anti-laminin, and nuclei. Representative photomicrographs after EdU, laminin, and DAPI staining are presented here. Scale bars: 50 μm. (F) Quantification of the EdU⁺ nuclei per unit area. n = 4 mice in each group. (G) Single myofibers were isolated from EDL muscle of Fn14^fl/fl and Fn14^scKO mice. After 48 hours of culturing, the myofibers were pulse-labeled with EdU for 60 minutes. Representative merged images of EdU⁺ and DAPI-stained myofibers are presented here. Scale bars: 100 μm. (H) Quantification of number of EdU⁺ cells per myofiber. n = 3 mice in each group. Analysis was done using 15–20 myofibers for each mouse. All data are presented as mean ± SEM. ^#P ≤ 0.05, values significantly different from WT myoblast, or corresponding muscle of Fn14^fl/fl mice, analyzed by unpaired Student’s t test.