Transposon-mediated stable reporter gene expression in CD34⁺ HPCs. (A) Bar graph represents the percentage of DsRed⁺ colonies generated by CD34⁺ cells after nucleofection using 15 μg SB transposon with 5 μg SB100X or SB11, or using 15 μg piggyBac transposon plus 5 μg piggyBac transposase. Median of 5 replicates is shown. There were no DsRed⁺ colonies derived from CD34⁺ cells transfected with SB transposon plasmid without transposase (data not shown). (B) Morphology of DsRed⁺ progenitor colonies. (Top panel) Dark field microscopic view (original magnification, ×100) of human hematopoietic committed progenitors. (Bottom panel) DsRed fluorescence of the same colonies. BFU-E indicates burst-forming unit-erythrocyte; CFU-GM, colony-forming unit-granulocyte/macrophage; CFU-GEMM, colony-forming unit- granulocyte/erythrocyte/monocyte/macrophage.