Fig. 5

Inhibiting axonal activity during early development decreases myelination in an axon-selective manner. a Representative images of sagittal sections of the corpus callosum at the midline of P20 mice that had been electroporated with plasmids containing either Kcnj2 and Gfp (Kir2.1) or Gfp only (Control) in utero at E15.5. White arrowheads indicate MBP⁺/GFP⁺ axons. b, c GFP⁺ axons in the Kir2.1-expressing mice displayed reduced myelination compared to GFP only electroporated controls (b), though the density of electroporated axons was comparable in both conditions (c). d Representative images showing MBP⁺/PAN-NF⁺ axons in the corpus callosum. e, f There was no difference in either the percentage of myelinated PAN-NF⁺ axons (e) or the density of MBP⁺ rings (f) between Kir2.1 mice and controls. g Representative images of the corpus callosum immunolabeled with OPC marker PdgfRa (red) and proliferation marker Ki67 (white). h–j There was no change in the density of proliferating cells (h), the total number of OPCs (i) or the density of proliferating OPCs (j) between Kir2.1 mice and controls. k Representative images of the corpus callosum immunolabeled with oligodendrocyte lineage marker OLIG2 (blue), mature oligodendrocyte marker CC1 (red), and GFP (green). l There was no significant difference in the density of mature oligodendrocytes between Kir2.1 and control mice. Welch’s corrected unpaired two-tailed t-test: ***P < 0.001; n = 10 mice/group (a–f), n = 5 mice/group (g–l),  ± s.e.m. Scale bars = 5 µm (a, d), 200 µm (g, k)