Fig. 8. Ultrastructural abnormalities in basement membranes of collagen IV-deficient embryos. Epidermal (A) and pial basement (B) membranes in E10.5 mutant embryos (–/–) are amorphously deposited or absent when compared to normal controls. In some areas the deposited material detaches from the surface of cells and forms irregular folds (arrow) or is almost completely absent (arrowhead). (C) Reichert's membrane of mutant embryos (E10) is significantly thinner than in wild-type in comparable areas and shows an altered texture. Additionally, detachment from trophectoderm (T) and parietal endoderm cells (pE) is observed (*). Scale bars: 0.2 µm.