Figure 5.

bax^-/-bak^-/- NPC cultures are able to differentiate along neural and glial lineages. NPC cultures were grown in the presence of N2 supplement, 1% FCS and FGF-2, in N2 supplement and 1% FCS, or in the presence of 10% FCS and BDNF. After 2 weeks in differentiation medium, cells were stained with antibodies against O1 (oligodendral marker), MAP2 (neural marker), and GFAP (astrocyte marker) (A), and quantitation is shown in B. Culture in N2, 1% FCS, and FGF-2 resulted in small cells with relatively short blunt processes that occasionally labeled with O1 but not with GFAP or MAP2. The morphology and O1 staining indicate that some of these cells are immature oligodendrocytes. In N2 and 1% FCS media, the cells become large and elaborate extensive processes. These cells show differentiation along the lines of mature neurons (MAP2 labeling) and mature oligodendrocytes (compare the complex morphology of the O1 labeled cells with N2 alone vs those with N2 and FGF) (B). No astrocytes were seen with the N2 media alone. FCS and BDNF, conditions known to differentiate astrocytes from NPCs, exhibit the expected result with large flat cells showing strong GFAP immunoreactivity. Under these conditions, no neurons or oligodendrocytes were observed. For percentages of differentiated cells from wild-type mice, see Results. Scale bar, 25 μm.