Fig. 5

Bmp signaling is required during early arch patterning for the appropriate expression of satb2.

(A, C, E) Lateral and (B, D, F) ventral images of 36 hpf embryos labelled with satb2 riboprobe. (A) The ventral region of the pharyngeal arches expresses satb2 robustly. (B) In the ventral arches, satb2 expression is strongest medially. (C, D) Inhibiting Bmp signaling via dorsomorphin from 20 to 36 hpf eliminates the majority of satb2 expression including that in the palatal precursors (arrowhead in C). Only a small population of crest in ventromedial arch 2 expresses satb2 following this treatment (arrows in C & D). (E, F) When Bmp signaling is blocked from 20 to 30 hpf and allowed to recover until 36 hpf, satb2 expression is still greatly reduced. Palatal precursors fail to express satb2 (arrowhead in E) and only ventromedial crest in arches 1 & 2 express satb2 (arrows in E & F). Later inhibition of Bmp signaling does not alter satb2 expression. (G–J) 42 hpf embryos labelled with riboprobe to satb2 in lateral (G, I) and ventral (H, J) views. In both control embryos (G, H) and embryos treated with dorsomorphin from 30 to 42 hpf (I, J), satb2 is strongly expressed by the palatal precursors and in the ventral pharyngeal arches. l, lateral; m, medial; p, palatal precursors.