(E) Ultrastructural analysis of myotubes treated or not with 3-MA at DM-2. Arrowheads point to mitochondria. Asterisks indicate electron-dense autolysosomes. N, nucleus. (F) Ratio of mitochondrialDNA/nuclearDNA in the indicated cultures (n = 3). (G) Ratio of mitochondrialDNA/nuclearDNA in E16.5 skeletal muscle (n = 3; *, P = 0.009). (H) Quantification of ATP in E16.5 skeletal muscle (n = 3; *, P = 0.011). (F-H) Error bars represent SD. *, P < 0.001. 