Fig. 4

a Experimental design in constitutive Tet1 or Tet2 knockout mice and controls. b, d Representative confocal image of spinal cord sections stained for 5hmC (green) and OLIG2 (red) at 14dpl in Tet1 (b) or Tet2 (d) mutant mice. White arrowheads indicate OLIG2 + cells with high levels of 5hmC immunoreactivity. Scale bar = 50 μm. c, e Percentage of OLIG2 + cells with high level of 5hmC in lesioned spinal cord sections at 14dpl in Tet1 (c) or Tet2 (e) mutants compared to that in wild-type mice. Dotted line indicates relative percentages in unlesioned white matter in the spinal cord (NWM). Average counts quantified in 3–4 sections/mouse for n = 3 control mice, n = 4 Tet1 mutants (c) and n = 5 for control and Tet2 mutants (e). Error bars represent SEM (**p = 0.0070 for (c), p = 0.8713 for (e), Student’s t test two-tailed). f, h Representative confocal images of spinal cord lesions stained for Fluoromyelin (green) at 14dpl in controls and Tet1 (f) or Tet2 (h) mutants (lesion area as white dashed line). Scale bar = 100 µm. g, i Fluoromyelin average intensity in control (gray bars) and Tet1 (red bar in g) or Tet2 (orange bar in i) lesions relative to the levels in unlesioned white matter (NWM) calculated for n = 3 control mice, n = 4 Tet1 mutants (g) and n = 5 for control and Tet2 mutants (i). Error bars represent SEM (***p = 0.0007 for g, p = 0.4304 for i, Student’s t test two-tailed). j Electron micrographs of remyelination (remyelinated axons indicated by white arrowheads) at 14dpl in Olig1^+/+;Tet1^fl/fl and Olig1^cre/+;Tet1^fl/fl spinal cords. Scale bar = 5 µm. k Percentage of remyelinated axons in controls (gray) and Tet1 mutants (red) at 14dpl, relative to total number of axons. Error bars represent SEM for n = 3 mice (*p = 0.0433, Student’s t test two-tailed). l Scatter plot of the g-ratio in myelinated axons of the indicated caliber in the lesioned spinal cord of wild-type mice (black) and Tet1 mutants (red) at 14dpl. A total of 107–150 axons were quantified for each mouse and n = 3 mice for each genotype were assessed (non-linear regression p = 0.501, comparison of slopes with sum-of-squares F Test). m Percentage of CC1 + cells with high level of 5hmC in lesioned spinal cord evaluated at 14dpl in mice of both genotypes. Dotted line indicates the percentage of CC1 + cells with high level of 5hmC in unlesioned tracts. Average counts from 3 quantified sections/mouse. Error bars represent SEM for n = 3 mice (*p = 0.0109, Student’s t test two-tailed). n Experimental design in inducible P60 Pdgfra-creER^(T)+/+;Tet1^fl/fl and Pdgfra-creER^(T)Tg/+;Tet1^fl/fl mice, after tamoxifen induction. o Percentage of OLIG2 + cells with high levels of 5hmC at 14dpl in Pdgfra-creER^(T)+/+;Tet1^fl/fl and Pdgfra-creER^(T)Tg/+;Tet1^fl/fl spinal cords, after tamoxifen induction. Dotted line indicates values in unlesioned tracts. Error bars represent SEM for n = 3 control mice and n = 5 inducible Tet1 mutants (***p = 0.0002, Student’s t test two-tailed). p Quantification of Fluoromyelin intensity in lesioned spinal cord at 14dpl, compared to normal white matter (NWM), in Pdgfra-creER^(T)+/+;Tet1^fl/fl and Pdgfra-creER^(T)Tg/+;Tet1^fl/fl after tamoxifen induction. Data represent the average intensity in lesioned compared to unlesioned areas. Error bars represent SEM for n = 3 control mice and n = 5 inducible Tet1 mutants (***p < 0.001, Student’s t test two-tailed).