FIGURE 3

olt mutants have reduced jaw movement. (A,B) Dorsal views with anterior to the left of the hindbrain of 48 hpf Tg(zCREST1:mRFP) in the olt background. (A) Wildtype (WT) sibling with facial branchiomotor (FBM) neurons (arrowheads) migrating into rhombomere 6 (r6). (B) In the olt mutant, FBM neurons (arrowheads) fail to migrate out of r4. (C) Gape frequencies in 5, 7, and 9 dpf olt mutant larvae were significantly reduced compared to wildtype siblings. Notably, the plateauing of gape frequencies after 7 dpf occurred normally in olt mutants. (D) Gape magnitude was significantly reduced in olt mutants compared to wildtype siblings at 5 and 9 dpf, but not at 7 dpf. (E) Gape events in representative 7 dpf olt mutant and wildtype sibling larvae showing reduced gape frequency in the mutant. (F) Gape event patterns were similarly proportioned between wildtype and olt mutant larvae at 5 dpf, with the distributed pattern being the predominant one. In 7 and 9 dpf wildtype larvae, the distributed pattern was almost exclusively seen. Statistical analysis was performed with a two-tailed student t-test (C,D) or Chi-square test (F). NS, not significant, *p < 0.02, **p < 0.001. Data pooled from 9 experiments (number of larvae in parenthesis).