Fig. 1. erbb3b and erbb2 mutants lack DRG and sympathetic neurons. (A-C) Elavl antibody labeling reveals DRG (arrowheads) and sympathetic neurons (asterisks). DRGs are segmentally arranged, whereas at this stage, sympathetics are not segmental. DRG and sympathetic neurons are present in wild-type embryos (A) but are absent from erbb3b (B) and erbb2 (C) mutants at 7 dpf. (D-F) Elavl-positive enteric neurons appear normal in erbb3b (E) and erbb2 (F) mutants compared with wild-type embryos (D). (G-I) TH antibody labeling reveals sympathetic neurons. Whole-mount labeling of 8 dpf larvae showing that sympathetic neurons (asterisks) are present in wild type (G) but absent from erbb3b (H) and erbb2 (I) mutants. (J-L) Whole-mount labeling of 31 hpf embryos with a neurog1 riboprobe reveals nascent DRG neurons. Nascent DRG neurons (arrowheads) are segmental in wild-type embryos (J) but absent from erbb3b (K) and erbb2 (L) mutants. (M-O) A neurod riboprobe reveals DRG neurons at 36 hpf. DRG neurons (arrowheads) are segmental in wild-type embryos (M) but absent from erbb3b (N) and erbb2 (O) mutants. Lateral views; anterior towards the left. Scale bar: 20 µm.