Figure 1.

Normal myelin formation in wild-type and netrin-1 and DCC mutant cerebellar organotypic cultures. Oligodendrocyte maturation and myelination in slices of newborn mouse cerebellum follows a similar time course to that in vivo and occurs normally in the absence of netrin and DCC. After 3 DIV, oligodendrocytes, immunolabeled with an antibody against MBP and visualized using Alexa 488-conjugated secondary antibodies (green), can be readily detected (A). They increase in number and complexity between 3 and 7 DIV (B). By 14 DIV, many myelinated axons are visible (C), and by 30 DIV, extensive myelination is observed throughout the white matter (D). Abundant myelination is observed in long-term slice cultures derived from both DCC^−/− and netrin-1^−/− mutant animals (F, H) and their wild-type littermates (E, G). Magnification: 20× objective. Scale bar, 100 μm.