BMI1 prevent apoptosis and maintains quiescence of CD34⁺CD38⁻ cells. After 48 hours of prestimulation, MoFlo-sorted CB CD34⁺CD38⁻ cells were transduced with MiGR1 or BMI1 virus for another 48 hours. Following transduction, single cells were deposited in 96-well plates and cultured in stroma-free conditions in IMDM supplemented with 20% FCS and KL, Flt3L, TPO, IL-3, IL-6, and EPO. Wells were evaluated for presence of alive and/or proliferating cells at 24 hours (A), 5 days (B), and 14 days (C) after sorting. The data shown are the average of 3 independent experiments where 210 individual clones were analyzed per group.