Defect in erythroid precursors in BM of Gata1s mice. (A-B) Representative flow cytometry plots (A) and bar graph (B) of mean ± SD for various stages of BM erythropoiesis in 2-month-old WT or Gata1s (G1s) male mice as assessed by staining with antibodies against Ter119 and CD44. (C-J) Analysis of the composition of BMCs by flow cytometry for hematopoietic progenitors in 2-month-old mice. Numbers indicate the percentage of cells within each gate as shown in the representative plots. (C-D) Representative flow cytometry plots and mean ± SD of MEP (Lin⁻c-kit⁺Sca-1⁻CD34⁻CD16/32⁻), granulocyte-monocyte progenitor (GMP) (Lin⁻c-kit⁺Sca-1⁻CD34⁺CD16/32⁺), and common myeloid progenitor (CMP) (Lin⁻c-kit⁺Sca-1⁻CD34⁺CD16/32⁻) cell populations from WT and G1s mice. (E-F) Lineage⁻Sca-1⁻c-Kit⁺ cells were further subdivided by expression of CD105 and CD41 into the megakaryocyte progenitors (MkPs, CD105⁺CD41⁺). (G-J) Lineage⁻Sca-1⁻c-Kit⁺CD34⁻CD16/32⁻ cells were further subdivided by expression of CD105 and CD150 into pregranulocyte-macrophage progenitors (pre-GMs, CD105⁻CD150⁻), the premegakaryocytic/erythroid progenitors (preMegEs, CD105⁻CD150⁺), and the pre-CFU erythroid cells (preCFU-Es, CD105⁺CD150⁺). Graphs depict mean (± SD) percentage of flow cytometry data. N_wt = 3, N_G1s = 4. ∗P ≤ .05, ∗∗P ≤ .01, ∗∗∗P ≤ .001 by the unpaired Student t test.