Fig. 7

Netrin-1-dependent filopodial protrusions in E16 axons and netrin-1-independent protrusions on the shafts of E14 axons. Netrin-1 was bath-applied to cortical cultures at a concentration of 250 ng/mL for 30 min, with or without 1 μg/mL anti-DCC antibody applied 30 min before the addition of netrin-1. The numbers of filopodial protrusions (12 μm or shorter and lacking a lamellipodial tip) were counted along the whole length of each primary axon. Error bars indicate the SEM (n = 7). a and b: significantly higher than a′ and b′, respectively, by Steel–Dwass test employed for comparisons among 3 test groups (that is, under basal conditions and after 30 min netrin-1 stimulation in the absence or presence of an anti-DCC antibody), within either E14 or E16 axons (p < 0.05). *p < 0.01 by Wilcoxon rank sum test, which was employed for comparisons between E14 and E16 axons subjected to the same treatment