Fig. 7. Deficiency of collagen IV does not affect the development of the vascular system, but causes aberrant organization of capillary structures. (A) The vascular system was detected by staining for ß-gal in E10.5 wild-type (+/+) and collagen IV-deficient (–/–) embryos on a Anxa5^+/LacZ background. No gross differences are seen in whole-mount stainings. Scale bar: 1 mm. (B) The capillary plexus forming close to the pial basement membrane is less dense in mutant (–/–) embryos and capillaries entering the neuroectoderm are irregularly arranged (arrows) and detected in lower numbers in collagen IV-deficient embryos than in littermate controls (+/+). Scale bars: 100 µm.