Fig. 2. Endothelial deletion of β1 integrins causes EC disorganization leading to cardiovascular defects and lethality at midgestation. Whole-mount anti-CD31 immunostained mouse yolk sacs at the indicated embryonic stages. The left panels of each e9.0 are capillary regions and the right panels are regions apparently undergoing arteriovenous remodeling. Note the disconnected capillaries and overall vascular disorganization in all mutants. Images are representative of at least five control/mutant embryo pairs at each stage. Scale bars: 100 µm for e9.5 and 50 µm for e9.0 and e10.5 Tie2-Cre; 25 µm for Tie1-Cre.