FIGURE 5.

p120RasGAP is required for netrin-1-dependent attraction. Control (CTL) or p120RasGAP (RASA) siRNA was electroporated with pGFP as a transfection reporter plasmid in E18 rat cortical neurons at 0 DIV. At 2 DIV, the neurons were exposed to a control PBS or a 200 ng/ml netrin-1 VI-V (n) gradient for 90 min. A–C, rose histograms representing the distribution of turned angles of cortical growth cones when exposed to a control PBS (A) or a netrin-1 gradient (B and C). Responses of individual neurons were clustered in 10° bins, and the percentage of total neurons per bin is represented by the radius of each segment (n = 99, 89, and 116 neurons, respectively). D, overlay of the rose histograms in B and C comparing the response to netrin-1 of control and p120RasGAP-deficient neurons. E, the turned angle percentage distribution of cortical growth cones in A–C. F, the mean turned angle (±S.E.) toward the gradient was measured in degrees for each condition. G, the mean displacement ± S.E. for a 90-min netrin-1 treatment was calculated. F and G, one-way ANOVA, Fisher's least significant difference post test; ns, not significant; *, p < 0.05.