Fig. 7. Endocytosis in the VE of E6.5 embryos is rescued completely by p96 but only partially by p67. TR-Tf uptake was assayed on embryos from heterozygous p96/+ or p67/+ intercrosses. (A-D') Bright-field images show that (A) control and (C) p96/p96 embryos are phenotypically similar. Fluorescent microscopy revealed similar uptake levels in both embryos at low magnification (B,D) and similar endosomal labeling in both (B') control and (D') p96 homozygous embryos. (E) Assays were scored as previously described. p67/p67 homozygotes showed a significant decrease in endocytosis of TR-Tf when compared with control embryos (P<0.005).