Initiation of hematopoiesis and vasculogenesis in murine yolk sac explants.

摘要: The blood islands of the visceral yolk sac (VYS) are initial sites hematopoiesis in mammals. We have developed a explant culture system to study process cell and endothelial development from extraembryonic mesoderm cells. No benzidine-positive cells or beta H1-globin mRNA expression was detected at primitive streak neural plate stage (E7.5). However, when isolated E7.5 dissected tissues were cultured for 36 72 hours serum-free medium, hundreds hemoglobin-producing embryonic globin gene identified both intact VYS explants. Explanted thus recapitulate vivo erythropoiesis do not require presence vascular network endoderm. Yolk also contain that arise by vasculogenesis express flk-1. flk-1 as early mouse embryogenesis. Culture embryo proper explants, which endoderm cells, produced capillary networks expressed In contrast, seen alone, although similar addition growth factor explants did induce formation. These results suggest its extracellular matrix is necessary coalescence developing into networks.