Figure 3.

Col5a2^−/− embryonic lethality at approximately 12 days post conception (dpc). Col5a2^−/− embryos (11.5 dpc), shown inside (A) or removed from (B) their yolk sacs, are pale compared with Col5a2^+/+ and Col5a2^+/− littermates, with an absence of clearly visible vasculature caused by a paucity of blood in the cardiovascular system, and with some pooling of blood in the embryo and yolk sac. C: Parasagittal sections of Col5a2^+/+, Col5a2^+/−, and Col5a2^−/− embryos 11.5 dpc, immunostained with α2(V)-specific antibody and counterstained with DAPI, have diminished or absent staining for α2(V) in Col5a2^+/− and Col5a2^−/− embryos, respectively. BM, basement membrane; Mes, mesenchymal layer; NE, neuroepithelium.