Figure 5

Inhibition of ROCK and MLCK signalling causes cranial motor axon guidance defects in chick hindbrain explants. (A-K,M,N) Stage 17 to 18 chick hindbrain explants cultured in collagen gels as controls or with the inhibitors ML-7 (MLCK) or Y27632 (ROCK) (10 to 20 μM), as labelled, and fixed at time 0 (A) or after 24 hours (all other panels), immunostained with anti-SC1 (red) and anti-Islet1/2 antibodies (green). In some cases (B,D,K,N) anti-Islet-1/2 immunostaining is shown as a single image of adjacent double-stained explant. (E,F,I) Rhombomere 4/5 level; (G,H) r6 level; (J,K,M,N) r6 to r8 level. Yellow arrows indicate boundaries of floor plate and arrowheads indicate axon pathfinding errors. Scale bar: (A-D) 100 μm; (E,F,J,K,M,N) 50 μm; (G-I) 25 μm. (L,O) Histograms representing the mean percentage of explants with three types of errors when treated with Y27632 (L) or ML-7 (O) compared with controls. Error bars represent standard error of the mean.