Fig. 4
From: Msx1 haploinsufficiency modifies the Pax9-deficient cardiovascular phenotype
Msx1 haploinsufficiency rescues the 3rd pharyngeal arch artery defect in Pax9–/– embryos. A The total number of cells within the mesenchyme of the 3rd and 4th pharyngeal arches (pa) per section were counted at E9.5 and E10.5 in control (n ≥ 5), CD1-Pax9–/– (n ≥ 4) and CD1-Pax9–/–;Msx1+/– (n = 3) embryos. There were significantly fewer cells in the 3rd arch in Pax9–/– and Pax9–/–;Msx1+/– embryos at E9.5, and in the 4th arch at E10.5, compared to control. In the 3rd arch at E10.5 there were significantly fewer cells in Pax9–/– embryos but the reduction in cell number was not significant in Pax9–/–;Msx1+/– embryos. B Immunostaining for neural crest cells (NCC) using an anti-AP-2α antibody was performed at E10.5 (n = 3 per genotype). C There were significantly fewer NCC in the 3rd arch in Pax9–/– and Pax9–/–;Msx1+/– embryos when compared to control but the NCC number in Pax9–/–;Msx1+/– embryos was significantly increased when compared with Pax9–/– embryos. In the 4th arch the reduction in NCC was significant in both mutant genotypes when compared to control. One-way ANOVA with Tukey’s multiple comparisons test. ns, not significant; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. D–F E11.5 embryo sections (n = 6 per genotype) were immunostained using an anti-αSMA antibody for smooth muscle cells (SMC) and an anti-ERG antibody for endothelium. In all control embryos, SMC surrounded the 3rd, 4th and 6th PAAs (D). In Pax9–/– embryos the 3rd PAAs had limited recruitment of SMCs (E) whereas in Pax9–/–;Msx1+/– embryos SMC were seen surrounding the 3rd PAAs (F). There are no 4th PAAs in Pax9–/– and Pax9–/–;Msx1+/– embryos. Somite counts (s) are indicated. Scale bars: 50 μm in B, 100 μm in D-F