Fig. 5. Expression of vgo/tbx1 pathway genes in mutants. Ventral views with anterior towards the left in all panels. (A,B) Expression of edn1 in wild-type (A) and vgo/tbx1 (B) 27 hpf embryos. (C,D) Expression of tbx1 in 25 hpf wild-type (C) and vgo/tbx1 (D) embryos. In vgo/tbx1 embryos, tbx1 mRNA is still present in cells ventral to the otic vesicle (Fig. 5D, arrows). At this stage, the otic vesicle in vgo embryos no longer express tbx1. (E,F) edn1 expression in 25 hpf wild-type (E) and vgo/tbx1 (F) embryos. In vgo/tbx1 embryos, edn1 expression is very much reduced in cells immediately anterior to the otic vesicle. The downregulation of edn1 in the arches is not due to the absence of cells, as tbx1-expressing cells are present (D). (G,H) Expression of hand2 in 34 hpf wild-type (G) and vgo/tbx1 (H) embryos. (I,J) Expression of crestin in 20-somite wild-type (I) and vgo/tbx1 (J) embryos. Absence of hand2 expression in the posterior arches of vgo/tbx1 embryos is not caused by the absence of neural crest cells, as revealed by the pan-neural crest marker crestin in vgo/tbx1 embryos (J). Arrows indicate neural crest cells ventral and posterior to the otic vesicle.