EPOR is expressed on a subset of UCB CD34⁺cells and is enriched in the CD34⁺CD38^–population. (A) Representative flow cytometry data showing EPOR and CD34 expression on UCB CD34⁺-enriched cells with gating strategy. (B) The percentage of CD34⁺, EPOR⁺, and CD34⁺EPOR⁺ expression on enriched UCB cells from 5 units with high purity (90% or higher CD34⁺ cells) by flow cytometry. (C) EPOR expression in enriched cells from 3 UCB units by western blot. (D) Representative flow cytometry data showing EPOR expression on UCB CD34⁺ cell subsets CD34⁺CD38^– and CD34⁺CD38^–. (E) EPOR expression by cell percentage (left) and MFI (right) on UCB CD34⁺ subsets. (F) Verification of EPOR shRNA transfection efficiency of UCB CD34⁺ cells by determining the percentage of GFP⁺ cells. (G) Micrograph showing GFP-expressing UCB CD34⁺ cells post lentiviral infection, confirming expression of EPOR shRNAs. Fluorescent images were taken at room temperature using an Olympus IX71 inverted microscope and Olympus DP71 camera. DP controller was used for software acquisition and Adobe Photoshop was used for image processing (scale bar represents 50 µm). (H) mRNA in EPOR knocked down UCB CD34⁺ relative to control confirming depletion of EPOR by RNAi. (I) Micrographs show formation of hematopoietic cell colonies. Erythroid colonies are shown on the right side with EPOR-depleted UCB CD34⁺ colonies shown in the right lower corner. Bright field images were taken at room temperature using an Olympus IX71 inverted microscope, 10x objective lens, and Olympus DP71 camera. DP controller was used for software acquisition and Adobe Photoshop was used for image processing (scale bar represents 200 µm). (J) Quantitation of CFU-G/M vs BFU-E colonies with or without EPOR-depletion. Single (*) and double (**) asterisks indicate statistical significance. CFU-G/M, colony-forming units–granulocytes and macrophages.