Fig. 3

Exogenous et-1 rescues ventral cartilage formation in suc mutants. (A-D) Ventral/oblique views of Alcian-stained larvae. In all panels, the black line marks the midline, the arrowhead marks the mouth, and white asterisks mark small ectopic elements (see Table 1). Dorsal and ventral cartilages are labeled as in Fig. 1 and joints are marked with arrows. (A) Uninjected wild type. Cartilages and joints are clearly identifiable (compare to Fig. 1C and D). (B) Uninjected suc mutant. Ventral cartilages are reduced, joints are absent, and the mouth is displaced ventrally. (C) pCS2-ET1 DNA-injected (20 pg) PCRgenotyped suc mutant (rescued left side). Ventral cartilages are present unilaterally, the mouth is no longer ventrally displaced, and the second arch joint has been partially rescued. (D) Unrescued right side of animal in C. This image has been vertically flipped for comparison with A-C. Ventral cartilages on the unrescued side are severely reduced while a ceratohyal (white arrow) is present on the contralateral rescued side. (E,F) Tracings of the cartilages in C and D, respectively, labeled as in A-D. (G,H) Dissected out and flat-mounted cartilages (labeled as in Fig. 1) from the rescued side of suc/et-1 mutants injected with 20 pg of pCS2-ET1 DNA (G) and human mature ET-1 protein (H) at 28 hours. Genotypes of all animals in C-H were confirmed by PCR-genotyping (see Materials and Methods). Scale bars, 50 μm.