Figure 6.

VEGF-dependent neural progenitor chemokinesis correlates with neuronal differentiation. A, Wild-type neurospheres were plated on poly-lysine-coated glass slides in a basal medium containing N2 complement and supplemented only with VEGF (20 ng/ml). Cells were immediately fixed (a–c) or left 2 h (d–f) and 8 h (g–i) in the presence of VEGF before fixation. Cells were stained with Hoechst for DNA (a, d, g) and double immunostained with anti-NG2 (b, e, h) and anti-Tuj-1 (c, f, i) antibodies. Scale bars: a–f, 20 μm; g–i, 40 μm. B–D, The effect of VEGF on neuronal differentiation. B, Representative wild-type neurospheres stimulated with VEGF for 24 h and double immunostained with anti-nestin (a) and anti-Tuj-1 (b) antibodies. Scale bars, 50 μm. C, D, Comparison of kinetics of neuronal phenotype acquisition between wild-type (C) and Iqgap1-null mutant (D) neurospheres. Wild-type and Iqgap1-null mutant neurospheres were stimulated with VEGF (20 ng/ml) for 8 and 24 h and double immunostained with anti-nestin and anti-Tuj-1 antibodies. Three differentiation stages were identified based on nestin and Tuj-1 immunoreactivities (see Results for details). Results are the average of three independent experiments, and significance was determined by comparison to the wild-type counterpart. **p < 0.01; ^#p < 0.005. Error bars indicate SEM.