Vascular abnormalities in partial EC-Rap1 KO embryos.

<p>Cranial hemorrhage is present in approximately 30% of EC-Rap1a^+/-Rap1b^-/- embryos (right panel) at E15.5 and contributes to increased lethality (44.7%) at weaning. No bleeding was observed in EC-Rap1a^-/-Rap1b^+/- embryos at E15.5 (center). Stereoscopic images are representative of n = 6 analyzed pregnancies resulting from Tie2-Cre^+/0; Rap1a^f/+, Rap1b^f/+ x Tie2-Cre^0/0; Rap1a^f/f, Rap1b^f/f crosses. Number of animals obtained (N_O) and expected (N_E), based on Mendelian distribution, as determined at weaning. Lethality was calculated using the following formula: (1-N_O/N_E)*100%.