Fig. 7
From: Msx1 haploinsufficiency modifies the Pax9-deficient cardiovascular phenotype
Skeletal defects in Pax9 mutant mice on an enriched CD1 background. Neonate skeletons were stained for cartilage (blue) and bone (red). A–C Forelimbs in control neonates were normal (A), but a pre-axial digit duplication was present in Pax9–/– (B) and Pax9ΔSHF;Msx1+/– (C) neonates (yellow arrowhead). D–F Skeletons were disarticulated to isolate the hyoid bone. G The ulna (u in A–C) of control (n = 5), Pax9–/– (n = 4) and Pax9ΔSHF;Msx1+/– (n = 6) neonates was measured. There was a small yet significant reduction in the average length of the ulna in Pax9ΔSHF;Msx1+/– neonates. H–J The ossification centre of the hyoid bone (asterisk in D–F), the length of the greater horn (gh) and the angle between the lesser (lh) and greater horns, were measured. K–P The tracheal rings (tr), thyroid (tc) and cricoid cartilages (cc) were examined. The superior horn (sh) of the thyroid cartilage was greatly reduced in size in Pax9–/– and Pax9ΔSHF;Msx1+/– neonates and the inferior horn (ih) was significantly reduced in length (Q). Fused tracheal rings were observed in Pax9–/– neonates (arrows; M, N). R, S The hyoid and thyroid cartilage were normal in neonates with a conditional inactivation of Pax9 from neural crest cells (Pax9ΔNCC). One-way ANOVA with Tukey’s multiple comparisons test. ns, not significant; **p < 0.01, ****p < 0.0001. Scale bars: 1 mm in A–C, 500 µm in E–G, J–O, R, S