Downmodulation of STAT5 by RNAi decreases growth of CD34⁺ stem/progenitor cells. (A) FACS analysis of transduced CB cells on MS5 coculture. MS5 cocultures were analyzed at week 3 for cells positive for CD14, CD15, and CD11b. The average percentage (from 3 independent experiments) of YFP/GFP⁺ cells positive for the respective markers is shown with standard deviations. (B) Transduced CD34⁺ CB cells in long-term coculture on MS5 stromal cells. Shown are average YFP (Renilla control) or GFP STAT5 RNAi percentages relative to week 1. A trendline is indicated and error bars denote standard deviations. N = 4. (C) Annexin V–APC stain of transduced CB cells on the indicated days in MS5 coculture. For day 7, the average percentage of annexin V–positive cells within the YFP or GFP gate from 3 independent experiments is shown with standard deviations. (D) Hoechst (5 μg/mL) cell-cycle labeling of YFP⁺ or GFP⁺ CB cells on the indicated days in MS5 coculture. For day 7, the average percentages of cells in G1, S, or G2/M phase of the cell cycle are shown from 3 independent experiments with standard deviations.