FIGURE 6.

The N terminus of p120RasGAP is sufficient to mediate netrin-1-dependent cortical axon outgrowth. Control (CTL) or p120RasGAP (RASA) siRNA was electroporated in E18 rat cortical neurons at 0 DIV with pGFP as a transfection reporter plasmid. Neurons at 1 DIV were incubated with 200 ng/ml netrin-1 (n) or 50 μm glutamate (g) or left unstimulated (−) for 24 h, and axon outgrowth was assessed in GFP-expressing neurons. A, control vector (v), full-length (FL), and NT p120RasGAP were co-expressed with control or p120RasGAP siRNA and pGFP in cortical neurons. Scale bar = 50 μm. B and C, axon outgrowth was measured and expressed as the average axon length (micrometer, mean ± S.E.) in at least three independent experiments (n in B = 381, 224, 272, 191, 228, 180, 146, 162, 222, 165, 179, and 182 neurons, and n in C = 299, 210, 381, and 190 neurons; two-way ANOVA, Fisher's least significant difference post test; ns, not significant; **, p < 0.005; ***, p < 0.001).