D171N-transduced cells lack long-term proliferation ability. Human CD34⁺ CB cells were transduced with the indicated vectors and cultured in complete cytokine medium (without IL-3 and IL-6). To examine proliferation ability of each transduced cell type, the cells were sorted for GFP expression and cultured in complete cytokine medium. Four independent experiments were performed, and the error bars represent the SD. (A) Proliferation curve of GFP⁺ RUNX1-transduced or control (empty vector-transduced) cells, nonsorted. (B) Growth patterns of the GFP-sorted transduced cells displayed as proliferation fold originating from 10° just after sorting. (C) Representative quantitative cell cycle analysis allowed the discrimination of cell subsets that were undergoing G0/G1 (a), S (b), or G2 + M (c) phases of the cell cycle, or apoptosis (d). (D) Percentage of CD34⁺ cells was determined by flow cytometry. (E) Representative CD34/CD38 expression pattern in long-term culture. (F) Images of Wright-Giemsa–stained cytospins on days 3 and 35 obtained with a BX51 microscope and a DP12 camera (Olympus); original magnification ×1000. (G) Morphologic abnormalities observed in Wright-Giemsa–stained cytospins of the D171N cells on day 35 in culture, myeloid, erythroid, and megakaryocytic cells with dysplasia are indicated by blue, pink, and green arrows, respectively, as captured with a BX51 microscope and a DP12 camera (Olympus); original magnification ×1000.