Fig. 8

Hyoid CNC is generated in moz mutants but forms mispositioned and misshapen condensations. Confocal micrographs of lateral views of the anterior pharyngeal arches in live wild-type (A,C,E,G) and moz mutant (B,D,F,H) embryos (A-F) and larvae (G-H) stained with the vital fluorescent dye BODIPY-ceramide at 28 hpf, 34 hpf, 48 hpf and 3.5 day stages. Images have been inverted; the dye fills interstitial spaces, so the inverted images show cells labeled in white and interstitial space in black. (A,B) Early CNC appears morphologically indistinguishable from wild type in moz mutants. Both first and second arches are filled with a cylinder of postmigratory CNC (Miller et al., 2000; Kimmel et al., 2001b), with no obvious defect in hyoid or branchial CNC in mutants. Other arch tissues also fail to show obvious morphological defects (C,D). At a slightly later stage the second pharyngeal arch in moz mutants appears slightly hypoplastic (D), but is still filled with CNC. (E,F) A day later, condensations have formed in the wild type (E), including in the second arch a dorsal hyomandibular condensation (arrow, compare with Fig. 2D) and a ventral ceratohyal condensation (arrowhead). In moz mutants, no dorsal second arch hyomandibular condensation is seen and cells appear as lose mesenchyme in this region (arrow in F). A dorsal mutant condensation does form, in the position of the wild-type symplectic condensation. The ventral mutant condensation is mispositioned anteriorly (arrowhead), and is abutting the first arch ventral condensation. The condensation pattern (E,F) largely prefigures the resultant larval cartilage pattern (G,H; compare with Fig. 2D,E). This figure shows two time points of four different animals: A and C are the same animal, as are B and D, E and G, and F and H. Arches are numbered in A-D.