Figure 4. Muscle MOTS-c and 12S rRNA transcription with aging.12S rRNA mRNA (MT-RNR1) and MOTS-c mRNA analysis technique (A). Young, middle-aged and older male muscle MOTS-c mRNA levels in the small RNA fraction were determined (B) and correlated with muscle MOTS-c protein expression (C), MT-RNR1 (D) and CYTB (E) mRNA levels in the small RNA fraction and MT-RNR1 mRNA levels in the total RNA fraction (F). MT-RNR1 mRNA levels in the total (G) and small (H) RNA fraction were correlated with MOTS-c protein expression. Muscle mitochondrial to nuclear DNA (mtDNA/nDNA) (I), and MOTS-c mRNA levels relative to mtDNA (J), and correlation of MOTS-c mRNA and MT-RNR1 mRNA in the total RNA relative to mtDNA (K). Significance was determined using linear regression or one-way ANOVA. Results are shown as means ± SE, due to limited sample availability and assay failure, for small RNA fraction assays n=14-18 per group, and for mtDNA n=26 for young, 24 for middle and 25 for old. *p<0.05, **p<0.01, ***p<0.001.