Figure 5: Jag1 attenuates Notch signalling imposed by Dll4 in the AGM.

(a) Heatmap displaying Notch pathway elements’ signature enrichment in E11.5 endothelial population (Kit−) and in Kit− and Kit+ cells on Jag1 incubation of the endothelial fraction (Kit−J and Kit+J, respectively). Highlighted genes are differentially expressed in Kit+_Kit− (Fig. 2); *represents differentially expressed in Kit−J_Kit−. Non-marked genes are not significant (P≤0.05). (b) Fold change expression levels using qRT–PCR of Notch pathway elements in E11.5 endothelial population on OP9-Jag1 incubation (Kit−J) compared with Kit− cells. The bars represent the average expression of 7 to 12 replicates from at least three independent experiments±s.e.m. Student’s t-test was performed (**P≤0.01; ***P≤0.001; ns, not significant; n.d., not detected). (c) Fold change expression levels using qRT–PCR of Notch pathway elements in Kit− (grey) or in Kit+ population (red) from E10.5 Jag1−/− compared with Jag1+/+. Bars represent the average expression level of five to six replicates from two independent experiments. Statistical significance was assessed by Student’s t-test (*P≤0.05; **P≤0.01; not significant, not assigned). (d) Confocal images of transverse sections of the dorsal aorta in two E10.5 embryos from Jag1+/+ and Jag1−/− stained with anti-cleaved Notch1 (green). Detail of the dorsal aorta corresponding to the boxed areas (right panels). *represents autofluorescent circulating cells. Scale bars, 50 μm in Jag1+/+, 25 μm in Jag1−/− embryos and for magnified regions.