Craniofacial and neural crest defects in bbs zebrafish morphants. (A–E) Ventral views of wholemount, Alcian Blue-stained, 5-dpf zebrafish. bbs8 morphants are most severe (D), with loss of pharyngeal apparatus (2D arrowhead), mandibles, and shortening of the chondrocranium. (F–J) Lateral views of larvae showing reduction of branchial arches and shortening of the mandibles in bbs6 and bbs8 morphants. (K–O) Flatmounts of neurocrania of controls and morphants. bbs8 morphants often have fusion of the trabeculae at the midline (arrowhead) similar to syu mutants. (P–T) Crestin in situ in 20ss embryos reveals streams of migrating NCCs in controls (arrowhead) with progressively fewer streams in bbs4, bbs6, and bbs8 morphants, respectively. (U–X) Sox10:eGFP expression in migrating streams (arrowheads) shows a similar reduction in the number of streams to the crestin expression. (Y) Quantification of the number of streams in morphants confirms a severe neural crest migration defect in bbs8 morphants that can be rescued by human mRNA. (Z and AA) dct expression in 27 hpf control embryos (Z) and bbs8 morphants (AA). [Scale bars: 500 μm (A–J), 100 μm (K–O), and 100 μm (P–X).]
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