Fig. 5. Compromised NCC contribution to the Frs2^cn/Nkx OFT cushions. (A) Immunostaining with anti-AP2 antibody reveals reduced numbers of migrating NCCs in the aortic sac (AS) and in pharyngeal arches (PAs) 3 and 4/6 in Frs2^cn/Nkx, but not in Frs2^cn/Mef, mouse embryos at E9.5. (B) The numbers of AP2⁺ cells in the aortic sac and in pharyngeal arches 3 and 4/6 as scored from five individuals (mean ±s.d.). (C) Co-immunostaining reveals that proliferation of cardiac NCCs is compromised in Frs2^cn/Nkx embryos. Proliferating cells are labeled with anti-phosphorylated histone H3 antibody (red), NCCs with anti-AP2 antibody (green) and nuclei with To-Pro3 (blue). Triple-positive cells are indicated by arrows. (D) Statistical analyses of proliferating cardiac NCCs from five individuals (mean ±s.d.).