Fig. 6: Noncompacted myelin suffices for internodal mitochondrial clustering.

a, b Example 3D renders of a PV⁺ axon of a (a) Mbp^WT or (b) Mbp^Shi mouse (see Supplementary Fig. 7). c Schematic representation of mitochondrial distributions in Mbp^WT and Mbp^Shi PV⁺ axons. d Mitochondria under myelin sheaths are larger in both Mbp^WT and Mbp^Shi mice (two-way ANOVA, myelination x genotype effect, P = 0.1481, F_{(1, 9)} = 2.504; myelination effect, P < 0.0001, F_{(1, 9)} = 125.5; genotype effect, P = 0.6304, F_{(1, 9)} = 0.2480; Bonferroni’s post hoc test, Mbp^WT MOG^– vs. MOG⁺, ****P < 0.0001; Mbp^Shi MOG^– vs. MOG⁺, ***P < 0.0001; MOG^– Mbp^WT vs. Mbp^Shi, P > 0.9999; MOG⁺ Mbp^WT vs. Mbp^Shi, P = 0.4792; Mbp^WT, n = 5 cells from 3 mice, MOG⁺, n = 72 mitochondria, MOG^–, n = 28 mitochondria; Mbp^Shi, n = 6 cells from 3 mice, MOG⁺, n = 78 mitochondria, MOG^–, n = 59 mitochondria). e Internode mitochondria in both Mbp^WT and Mbp^Shi mice are longer compared to those in unmyelinated axonal segments (two-way ANOVA, myelination x genotype effect, P = 0.5428, F_{(1, 9)} = 0.4000; myelination effect, P = 0.0002, F_{(1, 9)} = 35.16; genotype effect, P = 0.0045, F_{(1, 9)} = 14.13; Bonferroni’s post hoc test, Mbp^WT MOG^– vs. MOG⁺, **P = 0.0032; Mbp^Shi MOG^– vs. MOG⁺, **P = 0.0069; MOG^– Mbp^WT vs. Mbp^Shi, ^#P = 0.0825; MOG⁺ Mbp^WT vs. Mbp^Shi, *P = 0.0125; Mbp^WT, n = 5 cells from 3 mice, MOG⁺, n = 72 mitochondria, MOG^–, n = 28 mitochondria; Mbp^Shi, n = 6 cells from 3 mice, MOG⁺, n = 78 mitochondria, MOG^–, n = 59 mitochondria). f Number of mitochondria in PV⁺ axons of Mbp^WT and Mbp^Shi mice (two-way ANOVA, myelination x genotype effect, P = 0.0027, F_{(1, 11)} = 14.77; myelination effect, P < 0.0001, F_{(1, 11)} = 37.00; genotype effect, P = 0.1406, F_{(1, 11)} = 2.522; Bonferroni’s post hoc test, Mbp^WT MOG^– vs. MOG⁺, ****P < 0.0001; Mbp^Shi MOG^– vs. MOG⁺, P = 0.2549; MOG^– Mbp^WT vs. Mbp^Shi, P = 0.7802; MOG⁺ Mbp^WT vs. Mbp^Shi, **P = 0.0041; Mbp^WT, n = 6 cells from 3 mice; Mbp^Shi, n = 7 cells from 3 mice). g Segment lengths of PV⁺ interneuron axons in Mbp^WT or Mbp^Shi mice (two-way ANOVA, myelination x genotype effect, P = 0.0486, F_{(1, 11)} = 4.914; myelination effect, P = 0.0148, F_{(1, 11)} = 8.330; genotype effect, P = 0.1348, F_{(1, 11)} = 2.605; Bonferroni’s post hoc test, Mbp^WT MOG^– vs. MOG⁺, *P = 0.0104; Mbp^Shi MOG^– vs. MOG⁺, P > 0.9999; MOG^– Mbp^WT vs. Mbp^Shi, P > 0.9999; MOG⁺ Mbp^WT vs. Mbp^Shi, *P = 0.0315; Mbp^WT, n = 6 cells from 3 mice; Mbp^Shi, n = 7 cells from 3 mice). h Mitochondrial density is higher in internodes in both Mbp^WT and Mbp^Shi mice (two-way ANOVA, myelination x genotype effect, P = 0.0034, F_{(1, 11)} = 13.87; myelination effect, P < 0.0001, F_{(1, 11)} = 44.39; genotype effect, P = 0.4762, F_{(1, 11)} = 0.5441; Bonferroni’s post hoc test, Mbp^WT MOG^– vs. MOG⁺, ****P < 0.0001; Mbp^Shi MOG^– vs. MOG⁺, P = 0.1070; MOG^– Mbp^WT vs. Mbp^Shi, *P = 0.0168; MOG⁺ Mbp^WT vs. Mbp^Shi, P = 0.1919; Mbp^WT, n = 6 cells from 3 mice; Mbp^Shi, n = 7 cells from 3 mice). Solid horizontal bars indicate means, error bars indicate SEM, individual data points indicate cells. Source data are provided as a Source data file.