Yolk sac blood vessels of 9.5 dpc cubilin mutants fail to undergo remodeling. Anti-PECAM-1-labeled vasculature in a 9.5 dpc homozygous embryo (A), a 9.5 dpc wild-type (WT) embryo (littermate to that shown in A) (B), 8.5 dpc wild-type embryo (C) and 11.5 dpc homozygous embryo (D). The inset panel in B shows a higher magnification view of the remodeled yolk sac vasculature in the boxed region of the 9.5 dpc wild-type yolk sac. YS, yolk sac; A, allantois; NF, neural folds; H, heart. Bars in A and B = 500 μm. Bars in C and D = 200 μm.