Fig. 1

Fig. 1 Muscle contraction is necessary for craniofacial morphogenesis. (A) Left: Lateral view of control and tricaine-paralyzed zebrafish embryos at 120 hpf, using bright field microscopy. Right: Ventral view of flat-mounted Alcian blue stained control and tricaine-paralyzed zebrafish. (B) Left: Lateral view using bright field microscopy of control and nic mutant 120 hpf embryos. Lateral view (middle) and flat-mounted ventral view (right) of control and nic mutant zebrafish stained with Alcian blue. (C) Left: Lateral view using bright field microscopy of control and myf5/myod double morphant zebrafish at 120 hpf. Lateral view (middle) and flat-mounted ventral view (right) of control and myf5/myod embryos stained with Alcian blue. Asterisk indicates pericardial edema (A, B). Arrows indicate lower jaw (A)–(C). Double-headed arrows indicate relative location between Meckel′s and ceratohyal cartilages and between Meckel′s cartilage and the neurocranium (B, C). (D) Graph showing the reduction in ceratohyal length in paralyzed zebrafish compared to control (p<0.0001). Both right and left ceratohyal cartilages from twelve tricaine-paralyzed, eight nic mutant and a corresponding number of control embryos were measured at 120 hpf. (E) Graph showing the increase in the angle between ceratohyal cartilage and the midline (dashed line in A–C) in tricaine-paralyzed and nic mutant embryos compared to control (p<0.0001). The angle of both right and left ceratohyal cartilage of 6 tricaine-paralyzed and 11 nic mutants at 120 hpf was measured. Scale bars represent 100 μm. Abbreviations: m: Meckel′s cartilage, ch: ceratohyal cartilage, cb: ceratobranchials, pq: palatoquadrate, nc: neurocranium.