Smad4-overexpressing cells exhibit impaired repopulative capacity on xenograft transplantation. (A) CD34⁺ CB cells were transduced and unsorted cells were transplanted into NSG mice one day after transduction. The graph shows total human engraftment after 25 weeks in BM. (B) Representative FACS plots of GFP expression in recipient mice. (C) GFP⁺ cells present in PB after 3, 7, 12, and 25 weeks after transplantation. (D) Percentages of GFP⁺ cells in BM and (E) FACS analysis of CD34 expression in GFP⁺ cells from BM 25 weeks after transplantation. (F) PB lineage distribution of control and Smad4-transduced cells after 12 weeks in PB, ± SEM (n = 4). **P ≤ .01 (Mann-Whitney test). ***P ≤ .001 (Mann-Whitney test).