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Fig. 8
Loss of signaling molecules and transcription factors important in amniote palatogenesis causes craniofacial defects in zebrafish. A–L: Alcian blue and Alizarin red stained the cartilages and bones, respectively, of 5 days postfertilization (dpf) zebrafish. (A: Whole-mount lateral and (B) ventral views of an uninjected control craniofacial skeleton (arrowhead, palate; black arrow, Meckel′s cartilage). C: Flat mounted neurocranium. The anterior neurocranium or zebrafish palate is anterior to the dashed lines. A: Inset is a magnified view showing the three pharyngeal teeth present at this stage. D–F: fgf10a morpholino-injected fish have severely misshaped jaws and palate. D,E: Lateral and ventral views highlight the shortened ethmoid plate and jaw. F: Flatmount view of the neurocranium reveals the shortened ethmoid plate and misshaped trabeculae (arrowhead) and parasphenoid bone (asterisk). G–I: tgfb2 knockdown also causes shortening and misshaping of the jaw, ethmoid plate, trabeculae and parasphenoid. I: Misshaped shortened palate marked by arrowhead, misshaped parsasphenoid marked by asterisk. J–L: pax9a morpholino injection causes defects of the jaw, hyomandibular cartilage, palatal skeleton and teeth. J: Inset, shows the reduction in the number of teeth. K: Lateral view of flat mounted first and second arch-derived pharyngeal skeletal elements, control, (top half of panel) and pax9a morpholino-injected embryos (bottom half of panel). The second arch hyomandibular cartilage is reduced to a rod-like structure in this example (line). L: The palatal skeleton fails to fuse to the posterior neurocranium, arrowhead. Anterior is to the left in all panels. e, eye; ep, ethmoid plate; t, trabeculae.