A requirement for the receptor tyrosine kinase, Flk1, in hematopoiesis and vasculogenesis

grantor: University of TorontoThe Flk1 receptor tyrosine kinase is expressed on early hematopoietic and endothelial cells in the mouse embryo. Flk1$\sp{-/-}$ embryos die at the mid-somite stage, lacking both endothelial and hematopoietic cells. To further investigate the role of Flk1 signalling in vasculogenesis and hematopoiesis, the developmental potential of Flk1$\sp{-/-}$ embryonic stem cells in chimeras was examined. This analysis demonstrated a cell autonomous requirement for Flk1 in endotehlidal development. In addition, Flk1$\sp{-/-}$ cells did not contribute to primitive hematopoiesis in chimeric yolk sacs, or definitive hematopoiesis in adult chimeras and chimeric fetal livers. Furthermore, Flk1$\sp{-/-}$ were unable to reach the right location to form the blood islands, suggesting that Flk1 is involved in the movement of cells from the posterior primitive streak to the yolk sac.M.Sc