EpoR-eGFPcre mice were haploinsufficient. (A) Schematic model of EpoR-eGFPcre mouse model. (B) RBC parameters as indicated. N = 10. (C) (a) The number of BFU-E colonies in 5 × 10⁴ BM cells. (b) The number of CFU-E colonies in 5 × 10⁴ BM cells. (c) The number of erythroblasts in 2 tibia and 2 femur. N = 3. (D) Representative western blot (a) and quantitative results (b) of pSTAT5 levels. STAT5 level was used as loading control. N = 3. (E) Schematic model for generation of EpoR-tdTomato-Cre mice. (F) Polymerase chain reaction analysis showing the genotypes of EpoR-tdTomato-Cre mice. (G) western blot analysis showing the expression of tdTomato and Cre in BM cells of the EpoR-tdTomato-Cre mice. (H) Peripheral blood red cell parameters exhibiting no differences between EpoR-tdTomato-Cre mice and littermate control mice. N = 10. (I) BM erythroid colonies and erythroblasts showing no differences between EpoR-tdTomato-Cre mice and littermate control mice. N = 3. *P < .05; **P < .01; ***P < .001. HCT, hematocrit; HGB, hemoglobin; WT, wild type.