Fig. 1

cxcr4a, cxcr7b, and sdf1b expression in the zebrafish embryo. Dorsal views (A, B, C, F, G, H, K, L, M), lateral views (D, E, I, J, N, O) and anterior to the left. (A–E) cxcr4a expression. cxcr4a is observed in NCCs migrating to the arches (A). At 17 hpf (B) and 24 hpf (C) is expressed in the optic stalk (B, C; arrows) and pharyngeal arch region but is excluded from the central arch, likely corresponding to the mesodermal core. By 25 hpf, cxcr4a expression condenses into discreet arches (D). At 36 hpf, cxcr4a is expressed in the optic stalk and throughout the arches (E). (F–J) cxcr7b expression. From 14–17 hpf, cxcr7b is expressed in the midbrain, otic placode and in rhombomeres 3, 5 and 6 and, at 17 hpf, in the optic stalk (F, G; arrow in G to optic stalk). By 24 hpf, cxcr7b is expressed in the ventral region of the posterior pharyngeal arches (H, arrow). From 28–48 hpf, cxcr7b expression is seen throughout the pharyngeal arches (I, J). (K–O) sdf1b expression. At 14–17 hpf, sdf1b is expressed in the region of the migrating CNCCs, within the optic stalk and dorsal rim of eye (K, L; arrows in L and M). By 24 hpf (M) sdf1b is expressed in the typical scalloped pattern of the pharyngeal endoderm. At 25 hpf, sdf1b is expressed in endodermal pouches 1–3 (N) and pouches 1 and 2 at 36 hpf (O).