Fig. 7. Sox8-depletion leads to a broad range of defects in neural crest derivatives. (A) Embryos were co-injected in one blastomere on the dorsal side at the eight-cell stage with 20-30ng of Sox8mo and RNA encoding the lineage tracer ß-galactosidase. Well-defined pharyngeal arches are absent on the injected side when compared with the control side (arrow). Longitudinal section of the embryo shown on the left panel; the asterisks indicate individual pharyngeal arches on the control side. (B) Flat-mount Alcian Blue-stained skeletal preparations from control and Sox8mo-injected embryos at stage 45. Injected side is on the right. Sox8mo-injected embryos present different levels of skeletal defects. (C) A reduced number of Trp2-positive cells is observed in embryos that received 30 ng of Sox8mo in one blastomere at the two-cell stage. The control side shows a normal pattern of Trp2-expressing cells (arrows) at stage 33. Embryo is viewed from the lateral side, anterior towards the right (left panel) or anterior towards the left (right panel). (D) Histological analysis of Sox8mo- and Sox8mis-injected embryos at stage 42 and stage 47. In each panel, an arrow indicates the position of the dorsal root ganglia. Sox8-depleted embryos (Sox8mo) have no or reduced dorsal root ganglia on the injected side when compared with sibling to Sox8mis-injected embryos. For stage 42 embryos, only the injected side is shown. In sections of stage 47 embryos, the injected side is indicated by an asterisk.