Fig. 6: OSKM induction represses the expression of Wnt4 through p21.

a Heatmap shows the fold change of SCs niche-related genes in Cre⁺ EDL muscles compared to Cre⁻ EDL muscles. b The fpkm of Wnt4 and p21 in Cre⁻ and Cre⁺ EDL muscles. n = 2 independent biological samples. c Relative mRNA levels of Wnt4 and p21 in TA muscles after 2-days Dox treatment (2 days-on) and after 5-days Dox withdrawal (5 days-off). n = 4 Cre- mice for 2 days-on and 3 Cre− mice for 5 days-off. n = 5 Cre+ mice for 2 days-on and Cre+ mice for 5 days-off. Error bars represent mean + SD. d Relative mRNA levels of OSKM in single myofibers after 2-days Dox treatment. Error bars represent mean + SD of four independent biological samples. e Relative mRNA levels of p21 and Wnt4 in single myofibers after 2-days Dox treatment. Error bars represent mean + SD of four independent biological samples. f Western blots detection and quantification of the protein levels of p53 and p21 in TA muscles of Cre⁻ and Cre⁺ mice. Gapdh is the internal control. Error bars represent mean + SD of Cre⁻ 6 mice and 5 Cre⁺ mice. g Relative mRNA levels of p21 and Wnt4 in TA muscles with CAG-3xFLAG-p21 or CAG-Td plasmids. Error bars represent mean + SD of four mice. h Enrichments of the TATA-proximal region of the Wnt4 promoter by 3xFLAG-p21 as determined by ChIP assay using an antibody against FLAG. Error bars represent mean + SD of four independent biological samples. i Luciferase assay with a reporter containing the TATA-proximal region upstream of the minimal CMV promoter (Pmin). Error bars represent mean + SD of four independent biological samples. j Hypothetical model showing how OSKM regulates Wnt4. A two-sided unpaired Student’s t-test was performed.