Figure 5.

Myelination Defects Become Apparent in Schwann Cells Lacking HDAC3 as Myelination Reaches Completion

(A and B) Representative low- (A) and high- (B) magnification EM images of sciatic nerve sections from postnatal day 15 control (HDAC3^fl/fl) and mutant (HDAC3^ΔSC) mice. Note, while mostly normal, a low percentage of axons show hyper-myelination (white arrowhead). In addition, both control and mutant animals show mSCs with an enlarged cytoplasm (red ^∗) indicating that myelination is not complete.

(C) Quantification of normal myelination and the number of axons with myelination defects in HDAC3^fl/fl and HDAC3^ΔSC mice (n = 3 mean ± SEM).

(D) Graph shows the g-ratio as a function of axon diameter of the sciatic nerves from postnatal day 15 HDAC3^fl/fl and HDAC3^ΔSC mice (n = 3 > 600 axons/genotype).

(E) Representative EM images of longitudinal ultrathin sections (left panel), higher magnification (middle panel), and 3D reconstructions displaying axons (white) and their myelin sheath (blue) (right panel) of sciatic nerves from postnatal day 15 control (HDAC3^fl/fl) and mutant (HDAC3^ΔSC) mice showing, in both cases, one mSC with myelin outfoldings (top) and 2 normal mSCs (bottom).

^∗p < 0.05, ^∗∗p < 0.01. See also Video S2.