Differential responses of NSPCs expressing mutated forms of Rho GTPases after withdrawal of bFGF. (A) Anti-activated caspase-3 immunostaining of cultured NSPCs infected with recombinant adenoviruses expressing mutated forms of Rho GTPases. Activated caspase-3 immunoreactivity was observed in a small fraction of NSPCs (red). Similar extent of adenovirus infection was confirmed by immunostaining with anti-β-galactosidase antibody (green; CA mutations) or anti-GFP antibody (green; DN mutations). Bar, 20 μm. (B) Quantification of cells immunopositive with anti-activated caspase-3. Percentage of immunopositive cells is presented. There was a significant increase of cell death in cells expressing RhoCA (GFP control; 0.9 ± 0.3%, CdcCA; 2.6 ± 0.5%, CdcDN; 1.5 ± 0.6%, RacCA; 1.9 ± 0.2%, RacDN; 0.5 ± 0.3%, RhoCA; 8.0 ± 1,1% (ANOVA, p < 0.01), RhoDN; 0.8 ± 0.3%).