In vivo transduction of HSPCs with CFU potential. hCD46tg animals were mobilized and in vivo transduced with HD-Ad–GFP (n = 6 for 4 and 8 weeks, and n = 5 for 12 weeks after transduction) alone or with a combination of HD-Ad–GFP and HD-Ad–SB (n = 5 for 3 days, n = 10 for 4 weeks, n = 12 for 8 and 12 weeks, and n = 5 for 20 weeks post-transduction). Animals were euthanized 3 days, 4, 8, 12, or 20 weeks after transduction, BM cells were isolated, lineage depleted via MACS, and followed by the collection of GFP⁺ cells via fluorescence-activated cell sorting. Cells were then plated in CFU assays and colonies were scored 12 days after plating. (A) Experimental design. (B) Total colonies formed per 1000 plated Lin⁻ cells (left) and percentage of GFP⁺ colonies among total CFUs (right). Shown are single animals as well as group means. (Open circles, HD-Ad-GFP; filled squares, HD-Ad-SB + HD-Ad-GFP.) Two-way ANOVA with Bonferroni posttesting for multiple comparisons = n.s. ***P < .001. (C) GFP expression in progenitor colonies. Examples for GFP⁺ erythroid burst-forming units, CFUs of erythroid progenitors (erythroid CFU), granulocyte progenitors, granulocyte/macrophage progenitors, and multipotential progenitor cells (granulocyte, erythrocyte, monocyte, and megakaryocyte CFUs) are shown. The scale bar is 500 μm. No specific feature within images shown in panel C was enhanced, obscured, moved, removed, or introduced. BFU-E, erythroid burst-forming unit; CFU-E, erythroid CFU; CFU-G, granulocyte CFU; CFU-GEMM, granulocyte, erythrocyte, monocyte, and megakaryocyte CFU; CFU-GM, granulocyte/macrophage CFU; MACS, magnetic-activated cell sorting; n.s., not significant.