Re-expression of C/EBPα in STAT5A^1*6 CD34⁺ cells results in a restored myelopoiesis. (A) Human CB CD34⁺ cells were transduced with STAT5A^1*6-IRES2-EGFP and C/EBPα-ER-IRES2-NGF-R retroviral vectors. Representative transduction efficiencies are shown of cells grown for 1 week on MS5 stroma in the absence (left panel) or presence (right panel) of 4-OHT. (B) Cells shown in panel A were analyzed by FACS for the expression of CD14, CD15, CD36, and CD71 expression using allophycocyanin (APC)–conjugated antibodies. Data are representative of at least 3 independent experiments. (C) CB CD34⁺ cells were transduced with MiGR1/NGF-R empty vectors or double transduced with STAT5A^1*6 and C/EBPa-ER, cocultured on MS5 for 1 week in the presence of 4-OHT, after which MiGR1 cells, STAT5A^1*6 cells, C/EBPa-ER cells, and double-positive cells were sorted on the MoFlo and analyzed by cytospins and May-Grünwald Giemsa staining. (D) Experiment performed as described in panel C, but total RNA was isolated after MoFlo sorting for qRT-PCR analysis as indicated. The sorted cells for data in panels C and D were obtained from gates R2, R4, and R3, which represent C/EBPα-ER, STAT5A^1*6, and double-transduced cells, respectively. Double-transduced empty control cells were sorted separately (data not shown).