Figure 3. Targeting of Fbxw7 induced the upregulation of Dll4 expression.

Anti-Dll4 and Isolectin B4 (IsolB4)-stained retinal whole-mounts of Fbxw7 ^iECKO and littermate control retinas, as indicated (A, B). Arrowheads in (B) mark Dll4+ peripheral sprouts at the edge of the growing plexus, arrows indicate upregulated Dll4 in Fbxw7 ^iECKO retinal capillaries. Quantitative analysis (with Volocity 5; n = 3 for each group) of image data confirmed elevated Dll4 levels (number of pixels) in the mutant endothelium (C). Likewise, quantitative RT-PCR analysis showed reduced Fbxw7 expression but upregulated Dll4 transcript levels in P6 Fbxw7 ^iECKO lungs (D). Expression of the Cdh5 gene was used for normalization. Error bars indicate SEM. P values are indicated as ** (<0.001) and * (p<0.05). Scale bars are 100 µm.