Fig. 7. Rock1/2 inhibition impairs the orientation of axon outgrowth toward netrin 1 and the nuclear migration of PCN. (A) When E11 rhombic lip explants were exposed to 20 µM Y-27632 to inhibit Rock1/2 signaling, axons exhibited a tortuous aspect and grew toward and away from the netrin 1 source (Net). (B) Nuclear migration within those axons failed to occur. (C,D) Quantification revealed a gradual inhibition of nuclear migration from 5 to 100 µM Y-27632 (C; ^*P<0.001; P<0.01 compared with control), and a significant increase in proximal and distal axon growth at 20 µM (D; ^*P<0.001; P<0.01 compared with corresponding orientation in control; n=42 control, n=24 Y-27632 treated explants). (E) Migration/ougrowth ratio of treated and control explants (^*P<0.001 compared with control). Error bars in C, D and E represent s.e.m. Scale bars: A, 500 µm; B, 200 µm.