Figure 1

Spatiotemporal pattern of facial branchiomotor (FBM) neuronal migration in vivo and in explants. (A-C) Schematic representations of mouse embryonic hindbrain at embryonic stages (E)10.5 (A), E11.5 (B) and E12.5 (C). FBM neurons are shown by black dots and migrate from rhombomere (r)4 (E10.5) to r6 (E12.5). Grey patches represent dorsal exit points of motor axons. (D-F) Islet-1 in situ hybridisation on flatmounted hindbrains showing FBM neurons migrating from r4 to r6 at E10.5 (D), E11.5 (E) and E12.5 (F). (G-I) Hindbrain explants cultured on filters and immunostained with anti-Islet 1/2 antibody. Time 0 h (G) represents the beginning of culture period when some FBM neurons have started to migrate into r5. Time 24 h (H) shows that more FBM neurons are present in r5 and that some have started to turn dorsally into r6. Time 48 h (I) shows FBM neurons that have reached their final destination in r6 to form a nucleus. TN, trigeminal motor nucleus. Scale bars: 500 μm in (D-F); 250 μm in (G-I).