Fig. 6

The expression of signaling molecules involved in amniote palatogenesis is conserved in zebrafish. A,B: Schematic diagrams representing lateral view of 36, 40 hours postfertilization (hpf) and ventral view at 44, 48 hpf RNA in situ hybridizations respectively. Red boxes outline location of images, asterisks mark palate-forming cranial neural crest cells (CNCC). C,D,G,H,K,L,O,P,S,T,W,X: Lateral views at 36 and 40 hpf (E,F,I,J,M,N,Q,R,U,V,Y,Z) ventral views at 44 and 48 hpf. Arrowheads indicate areas of CNCC expression black for maxillary and white for mandibular, while arrows indicate expression in oral ectoderm. In all images the oral ectoderm is outlined by white dashes to aid in its visualization, ventral views, only one side of the embryo is outlined. C–F: The oral ectoderm expresses shh at all time points examined, out of focus expression is shh expression in the brain (b). G–J: Both anterior oral ectoderm and frontonasal and maxillary CNCC express fgf10a from 36 to 40 hpf. fgf10a CNCC expression and oral ectodermal expression remains at 44 hpf. K–N: A subpopulation of anterior CNCCs and the oral ectoderm express bmp2b at 36 and 40 hpf. By 44 hpf this expression expands to include more posterior CNCCs. Likewise, over time an anterior oral ectoderm expression domain of bmp2b expands to include more posterior oral ectoderm. O–R: At 36 and 40 hpf bmp4 expression is in the oral ectoderm (arrow) and the frontonasal and maxillary CNCC, although there appears to be a gap between the maxillary and frontonasal expression domains. The oral ectodermal expression of bmp4 does not expand and CNCCs lose expression by 48 hpf. S–V: tgfb2 is initially weakly expressed in an anterior domain of maxillary CNCC at 36 and by 40 hpf the expression is stronger. W–Z: The oral ectoderm expresses tgfb3 at all time points. At 36 and 40 hpf, a small population of maxillary CNCC express tgfb3. By 44 hpf this CNCC expression has greatly expanded to include most, if not all, palatal CNCCs. e, eye; mx, maxillary domain; md, mandibular domain; fn, frontonasal CNCC; cf, choroid fissure; oe, oral ectoderm; ea, ear.