Effects of knockdown of vdr on the craniofacial cartilage development. Craniofacial cartilages were stained with Alcian blue in 4 days post-fertilization (dpf) larvae. (A,E) Wild-type controls. (B,F) vdra morphants. (C,G) vdrb morphants. (D,H) vdra/b morphants. Close-up of head lateral (A–D) and ventral (E–H) views are shown. Larvae injected with vdrb MO display absence, reduction, and malformations of cartilage components compared to controls or vdra morphants. These phenotypes are completely penetrant and consistent in vdrb morphants. The double knockdown of both vdra and vdrb leads to more severe defects, complete loss of cartilage. n ≥ 10 embryos/condition. Scale bars = 100 μm. Arrows point to reduced or malformed cartilage elements and asterisks denote missing cartilages. M, Meckel’s cartilage; PQ, palatoquadrate; CH, ceratohyal; CB, ceratobranchial; N, neurocranium; HS, hyosymplectic.