Overexpression of CHCHD4 blocks exercise-induced p53 nuclear activity.
A, p21 mRNA and protein levels in skeletal muscle of WT and CHCHD4 Tg mice in unexercised control (−) and 12 h post-exercise (+) states. Tubulin and VDAC served as protein loading controls for whole tissue (total) and the mitochondrial fraction, respectively. n = 4. B, mRNA expression of p53-regulated genes analyzed by RT-PCR array in skeletal muscle of WT and CHCHD4 Tg mice 12 h after a 60-min period of submaximal treadmill exercise. Of the 84 p53 target genes, 26 were induced 2.5-fold or higher only in WT mice after exercise. Color-coded -fold change in gene expression after exercise compared with non-exercised controls is shown (red, induced; green, repressed). n = 3. C, confirmation of some representative exercise-induced p53-regulated genes identified by RT-PCR array. n = 3. Values are mean ± S.E. *, p < 0.05; **, p < 0.01.