(A) Cross section of P10 wild-type myelin sheath with outer layers compacted (black arrows) and inner layers non-compacted (white arrows). (B) Amount of myelinated axons with non-compacted layers in wild-type and shiverer heterozygote (Shiv +/-) optic nerves between P10 and P21. (C) Immunoelectron micrograph for MBP of a partially compacted myelin sheath of P10 wild-type optic nerve (black arrows pointing at compacted layers and white arrows to the non-compacted layers). Scale bars= 200nm. Gold size= 10nm. (D) Quantification of MBP labeling per µm of membrane in the compacted and non-compacted layers of P10 wild-type myelin sheaths. (E) Amount of myelinated axons with non-compacted layers in wild-type, Shiv +/-, CNP +/- and CNP -/- at P10. Bars show mean ± SD (n=3-5, 120-200 axons per animal, **p < 0.01, ***p < 0.001, t-test). See also Figure S6.