Expression of Gfi1b in granulocytes and monocytes of the adult mouse. (A) Cells from different tissues of the hematopoietic system of adult wt or Gfi1b^+/GFP mice or from fetal livers of wt, wt/KI (Gfi1b^+/GFP), or KI/KI (Gfi1b^GFP/GFP) embryos, respectively, were stained with antibodies against the surface markers B220 and Mac-1 and subjected to FACS analysis. B220-negative but Mac-1–positive living cells were electronically gated and analyzed for GFP expression. (B) Cells from bone marrow (BM) or peripheral blood (PB) from adult mice of the indicated genotypes were additionally stained for GR1 and analyzed by FACS. GR1^high granulocytes and GR1^low monocytes were electronically gated (left) and analyzed for GFP expression (right).