Fig. 6. Defect in oligodendrocyte differentiation in Ascl1^-/- spinal cords. (A-H) Co-immunostaining of CNP, MAG and MBP with Olig2 in wild type (A-D) and Ascl1^-/- mutants (E-H). Boxed areas in A and E indicate the regions shown in other panels. Arrowheads indicate double-positive cells. Asterisks indicate non-specific staining outside the spinal cord. (I) Reduction of myelin⁺ oligodendrocytes in Ascl1^-/- mutants at P0. Data are mean±s.d. obtained from staining of five or six sections derived from three embryos for each genotype. The percentage of the mutant level compared with the wild type is shown for each marker. ^*P<0.01. (J-M) Expression of GalC and NG2 (J,K) and MBP (L,M) in culture of wild-type and Ascl1^-/- embryos. Cells from E18.5 spinal cords were cultured for 7 days. In J and K, arrows indicate NG2^-/GalC⁺ oligodendrocytes, whereas arrowheads indicate NG2⁺/GalC⁺ intermediate cells. In L and M, arrows indicate MBP⁺ oligodendrocytes. Cell nuclei were stained with DAPI (blue). (N) Differentiation of MBP⁺ oligodendrocytes in vitro. Culture of E18.5 spinal cords was performed either the presence (+) or absence (-) of TH, and the percentage of MBP⁺ cells among total cells was quantified at DAP1 and DAP7 (mean±s.d., three independent experiments). Parentheses show the percentages of the mutant level compared with the wild type. ^*P<0.05, ^**P<0.01 compared with the wild type. Scale bars: in A,E, 200 µm; in D,H, 50 µm for B-D,F-H; in M, 50 µm for J-M.