Progenitor expansion in W51-transduced CD34⁺ cells cultures. Colony assays of sorted MIGR1- and W51-transduced CD34⁺ cells. Week-0 cells were plated after transduction and sorting. (A) Total colonies were enumerated in triplicate at each time point. (B) The lineage distribution of colonies (CFU–granulocyte-erythrocyte-megakaryocyte-macrophage [CFU-GEMM], CFU-GM, CFU-M, BFU-E) from week-0 sorted cells. The data shown are representative of 3 separate experiments. (C) Representative BFU-Es generated from the week-0 colony assay of sorted W51⁺ cells (C, 1). Note the terminally differentiated erythrocytes (C, 2) within the BFU-Es. (D) RT-PCR evaluation of the α-globin mRNA in EGFP⁺ sorted cells expressing W51 Flt3-ITD and MIGR1 control. Total RNA was isolated and used as described in “Materials and methods” for RT-PCR.