Fig. 2

Neural crest-specific function of Prdm3 and Prdm16 is required for chondrocyte organization in the Meckel's cartilage of the developing murine mandible. (A-J) Prdm3^fl/fl or Prdm16^fl/fl female mice were bred to Prdm3^fl/+;Wnt1-Cre^+/Tg or Prdm16^fl/+;Wnt1-Cre^+/Tg males and embryos were collected at the indicated time points. (A-C) Lateral images of the head show snout defects (white arrowheads) and mandible hypoplasia (white lines) in Prdm3 and Prdm16 mutants. (A′-C′) Alcian Blue- and Alizarin Red-stained mandibles were dissected from control or mutant animals. (A″-C″) Lateral views of the right half of the mandible. ap, angular process; cd, condylar process; cp, coronoid process; md, mandible. Black arrowheads and double arrowheads denote morphological irregularities in the mandible. (D,E) Quantification of anterior mandibular hypoplasia (ratio between the length of the anterior and posterior portions of the mandible; E) as schematized in D (n=3 per genotype); mean±s.d. (F-H) Safranin O- and Fast Green-stained sagittal sections of the Meckel's cartilage at E14.5 in control (F), Prdm3 (G) or Prdm16 (H) mutants. Scale bars: 100 µm. (F′-H′) High-magnification images of the chondrocytes from the boxed regions in F-H. Scale bars: 100 µm. (F″-H″) Schematics showing chondrocyte cell shapes. (I,J) Quantification of chondrocyte cell area (I) and cell number per tissue area (J) (n=3 per genotype); mean±s.d. *P≤0.05, **P≤0.005, ^#P<0.1; ns, not significant (unpaired, two-tailed Student's t-test).