Deformities of pharyngeal cartilage in vwa1 morphants and mutants. (A) Deformities of pharyngeal cartilage in vwa1 morphants. The figure shows the jaws of uninjected and vwa1 morpholino (MO)-, p53 MO- and vwa1 + p53 MO-injected morphants under a stereoscope and Alcian blue staining of morphant embryos. Injection of 1 ng vwa1-ATG MO caused jaw structures to almost completely disappear (b, f, and g). Injection of 1 ng vwa1-ATG MO with p53 MO reduced the overall size of jaw structures at 4 dpf compared with uninjected controls and 1.5 ng p53 MO-injected morphants (a and d), whereas there was no significant difference compared with controls after injection of p53 MO (a–d and i–l). The first and second pharyngeal arches were severely hypoplastic (brown ⋆ in h and l), and the third to seventh pharyngeal arches (Cb1-5, circled in e) were absent (h). Joint junctions were abnormal: the angle between cartilage derived from the first pharyngeal arch, Meckel’s (M) and palatoquadrate (Pq) became smaller, whereas the angle between cartilage derived from the second pharyngeal arch ceratohyal (Ch) became larger (brown ⋆ in h and l). (B) Deformities of pharyngeal cartilage in vwa1-knockout mutants. a, b, c, and d shows Alcian blue staining results for uninjected embryos and embryos injected with vwa1 gRNAs, upf3a MO, and vwa1 gRNAs together with upf3a MO. Embryos injected with vwa1 gRNAs or upf3a MO showed no significant deformities in pharyngeal cartilage compared with uninjected embryos (b and c). Injection of vwa1 gRNAs together with upf3a MO resulted in pharyngeal cartilage deformities similar to those in vwa1 morphants, including hypoplasia of first and second pharyngeal cartilages, disappearance of the third to seventh pharyngeal arches, and abnormal joint junctions (brown ⋆ in d).
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