Pcgf1 is predominantly expressed in HPCs. (A) BM of Runx1^Δ/Δ (dark gray) or control mice (Runx1^fl/fl, light gray) isolated and separated into 2 fractions that either were enriched for HSPCs (Lin⁻) or contained mature blood cells (Lin⁺) are shown. RNA isolated from these cells was analyzed by qRT-PCR for the expression of Pcgf1. Data were normalized to β-actin levels. Mean values of 3 independent experiments are shown. Significance was determined by the Student 1-tailed t test. **P < .01. (B) Microscopic analysis of lineage-depleted BM cells from Pcgf1-eGFP mice. Cells stained for eGFP, DAPI, and α-tubulin are presented. Samples were analyzed by a Deltavision microscope and pictures were deconvoluted. In the overlay, eGFP is depicted in green, DAPI in blue, and α-tubulin in red. (C-D) Representative FACS profiles of BM cells from Pcgf1-eGFP mice. Cells stained with indicated Abs or corresponding isotype controls are shown. Populations were defined as follows: stem cells (LSK) (Lin⁻cKit⁺ Sca-1⁺), MPCs (Lin⁻cKit⁺Sca-1⁻), common myeloid progenitors (CMP) (Lin⁻cKit⁺Sca-1⁻CD34⁺FcγRII/III⁻), GMPs (Lin⁻cKit⁺Sca-1⁻CD34⁺FcγRII/III⁺), megakaryocyte-erythrocyte progenitors (MEP) (Lin⁻cKit⁺Sca-1⁻CD34⁻FcγRII/III⁻), and common lymphoid progenitors (CLP) (Lin⁻IL-7Rα⁺cKit^loSca-1^lo). (C) Comparison of LSK populations before (right panel) and after (left panel) gating for eGFP⁺ cells. (D) Mean fluorescence of different hematopoietic cell populations. Gray histogram indicates control mice; clear histogram, Pcgf1-eGFP mice. (E) Percentage of eGFP⁺ cells from different cell populations of Pcgf1-eGFP mice. Error bars indicate the SD from the mean percentage values of 9 different animals.