Hoxb4 is expressed in CD45⁺CD144⁺ cells and HSCs from the E11.5 AGM. (A) AGM regions from WT and Hoxb4^YFP/+ embryos were analyzed by flow cytometry with the use of CD45 and VE-cadherin markers. (B) Histograms comparing YFP fluorescence are shown for the endothelial, hematopoietic, and double-positive (DP) cell populations. In the histograms dashed lines indicate WT and solid lines indicate Hoxb4^YFP/+ cells. (C) Cells from E11.5 AGM region were sorted on the basis of YFP expression and injected into irradiated recipients. Donor contribution to the peripheral blood is displayed (data obtained from 2 independent experiments).