Fig. 5

Cyclopamine treatment causes a failure of enteric precursors to populate the entire length of the intestine and to differentiate into enteric neurons and also results in a failure of intestinal smooth muscle differentiation. (A, D, G, J) Wildtype control embryos, (B, E, H, K) 24–26 hpf cyclopamine treated embryos (C, F, I, L) 36–60 hpf cyclopamine treated embryos. (A–C) Lateral view of 60 hpf wholemount embryos hybridized in situ with a phox2b antisense probe to reveal the distribution of ENS NNC precursors in the intestine. Treatment with cyclopamine results in a significant reduction/absence of ENS precursors along the length of intestine. (D–E) Lateral view of 60 hpf wholemount in situ hybridized embryos hybridized with a myh11 antisense probe. Treatment with cyclopamine results in a loss of this early smooth muscle marker expression in the intestine. (G–I) Lateral view of 72 hpf wholemount in situ hybridized embryos hybridized with a α SMA antisense probe. Treatment with cyclopamine results in a loss of this late smooth muscle marker expression in the intestine. (J–L) Lateral views of 96 hpf HuC-gfp embryos stained with anti-GFP antibody to shows a significant reduction in the number of enteric neurons in the intestine of cyclopamine treated embryos. Treatment conditions are indicated in lower right corner of each panel. Black arrowheads (B, C) indicate the few phox2b expressing cells in the intestine of cyclopamine treated embryos. Arrow (E) indicates pharyngeal arch myh11 expression. White arrowheads (L) indicate differentiated neurons in the intestine. Anterior is to the left.