Electron micrographs of developing sciatic nerves. Representative electron micrographs of sciatic nerve cross-sections of shRNA transgenic mice (TG) or nontransgenic littermates (NTG) at 3 d old, 14 d old, and 1 month old. Scale bar, 5 μm. Scatter plots of the g-ratio derived from electron micrographs of the sciatic nerves in transgenic mice (a total of 70, 74, and 73 nerves in two independent mice at 7 d old, 14 d old, and 1 month old, respectively) and nontransgenic mice (a total of 87, 54, and 70 nerves in two independent mice at 7 d old, 14 d old, and 1 month old, respectively) for each axonal size are shown. The average g-ratios are also shown.