Figure 4.

 Impaired differentiation of p27−/− oligodendrocyte progenitors. Phase contrast photomicrographs of cultures obtained from p27+/+ (a,c) and p27−/− mice (b,d) maintained in serum-free differentiation medium for 5 days. The majority of p27+/+ precursors differentiate into mature oligodendrocytes, identified by the characteristic highly branched morphology (a,c). In contrast, the majority of p27−/− cultures are characterized by cells with few simple processes (b,d). (a,b) Bar, 30 μm; (c,d) bar, 40 μm.