Fig. 4: ATF3 re-expression in iKO reverts the accelerated SC activation and muscle regeneration.

a FISCs from Ctrl or iKO mice were infected with ATF3-overexpressing lentiviruses and stained for Pax7 (green) and Myod (red) after 48 h. Scale bar: 50 μm. p = 0.0050. b EdU assay was performed and EdU+ cells were quantified. Scale bar: 50 μm. p = 0.0031. c Schematic for overexpressing ATF3 in vivo. ATF3 expressing lentiviruses were injected into Ctrl or iKO TA muscles 1 day after BaCl₂ injury. The muscles were collected 5 days after infection for analysis. d H&E staining of the above TA muscles. Scale bar: 50 μm. e IF staining of eMyHC (red) and Laminin (green) was performed on the above TA muscles. Scale bar: 50 μm. f The numbers of eMyHC+ fibers per view were quantified. p = 0.0044, 0.00081, 0.015 and 0.0072. g The numbers of Pax7+ cells per view on the above TA muscles were quantified. p = 0.00018, 0.041, 0.098 and 0.00040. h The numbers of Myod+ cells per view on the above TA muscles were quantified. p = 0.016, 0.0058, 0.0010 and 0.0019. n = 3 mice per group (a, b); n = 4 mice per group (d–h). All the bar graphs are presented as mean ± SD. Student’s t test (two-tailed unpaired) was used to calculate the statistical significance (a, b, f–h): *p < 0.05, **p < 0.01, ***p < 0.001. n.s. no significance. Source data are provided as a Source Data file.