Fig. 6

suc/et-1 is required for ventral neural crest specification in the arch primordia. Lateral views of whole-mount embryos processed for single color (A-F) or two-color (G,H) in situ hybridization. In all panels, the arches are numbered, and pharyngeal pouches are marked with black dots. (A-B) 24 hours, msxE expression in wild type (A) and suc/et-1 mutant (B). Ventral mesenchymal cells in the first three arches express msxE in wild types, but do not in suc/et-1 mutants. (C-D) 30 hour, gsc expression in wild type (C) and suc/et-1 mutant (D). In wild types, gsc is expressed in separate patches of dorsal and ventral mesenchyme in the second arch. In suc/et-1 mutants, dorsal cells express gsc while ventral cells do not. (E-F) 24 hours, dlx3 expression in wild type (E) and suc/et-1 mutant (F). In wild types at this stage, dlx3 is expressed in ventral but not dorsal mesenchyme in arches one, two, and four. In suc/et-1 mutants, ventral cells fail to express dlx3. (G-H) 32 hours, dlx2 (red) and EphA3 (blue) expression in wild type (G) and suc/et-1 mutant (H). EphA3 expression is ventrally restricted similar to dHAND. In suc/et-1 mutants, EphA3 expression is severely reduced in the first four arches. Fig. 5 should be referred to for the dlx2 defect in suc/et-1 mutants. e, eye; o, otic vesicle. Scale bars: 50 μm.