Fig. 6
From: Two adhesive systems cooperatively regulate axon ensheathment and myelin growth in the CNS
Loss of internodal and paranodal adhesion results in overgrowth of nodes of Ranvier. a Electron micrograph of a P21 Caspr−/−Caspr2−/−Mag−/− mouse optic nerve cross-section. Asterisks indicate double myelin sheaths. b Double myelin sheaths in optic nerve cross-sections of P21/P22 mice, 10 frames (219 µm2) analyzed per animal (n = 2–9; one-way ANOVA: p < 0.0001). c Electron micrographs of optic nerve longitudinal sections of P21/P22 wt and Caspr−/−Caspr2−/−Mag−/− mice. d Serial block-face SEM (FIB-SEM) of a P21 Caspr−/−Caspr2−/−Mag−/− optic nerve (13 × 6 × 35 µm), Longitudinal view and cross-sections at different z-levels (left): A second myelin sheath (green) encloses an axon (blue) that is already myelinated (orange). 3D reconstruction (right) shows the axon alone (top), compacted myelin around the axon (middle) and an additional myelin sheath on top (bottom). Numbering refers to cross-sections. e–g Model, electron micrograph and quantification of normal nodes (e), loops under myelin (f) and loops on top of myelin (g) in a 26.000 µm2 hexagon grid (n = 3). One-way ANOVA: p < 0.001 (normal nodes and loops on myelin), p < 0.005 (loops under myelin). h Optic nerve longitudinal sections from wild-type (wt) and Caspr−/−Caspr2−/−Mag−/− mice immunostained for Nav1.6+ sodium channels and pan-neurofilament. i Number of Nav1.6+ sodium channels in wt and mutant animals (n = 4–6, one-way ANOVA: p < 0.0001). p values, * < 0.05, ** < 0.01, *** < 0.001. Data are presented as means ± s.d. Scale bars, 500 nm (c, e, f, g), 1 μm (a, d (2D sections)), 2 μm (d (3D reconstruction)), 50 μm (h). Source data are provided as a Source Data file
