Enforced TAL1 expression amplifies SRC-derived CFCs and LTC-ICs. (A) SRC-derived CD34⁺/CD38^lo cells were purified by cell sorting from the NOD-SCID bone marrow, and their function was studied in different culture conditions. (B) The progeny of sorted CD34⁺/CD38^lo cells was counted and analyzed by FACS after 3 weeks of culture in lymphomyeloid conditions. Results are expressed as the percentage (upper quadrant) and as the absolute number (lower quadrant) of CD19⁺ B cells and CD15⁺ myeloid cells. (C) Sorted CD34⁺/CD38^lo cells were cultured in methylcellulose for the detection of human CFCs. Results are expressed in absolute numbers of CFCs generated for 1000 plated cells. Fold increase in absolute numbers of cells or of CFCs between GFP⁺ cells and TAL1⁺ cells is indicated (A-B). (D) CD34⁺/CD38^lo cells were cultured at limiting dilutions in LTC conditions. Frequencies of LTC-ICs were calculated according to Poisson statistics and are indicated for GFP and TAL1 transgenes. (E) mRNA levels of KIT, Bmi1, HOXB4, GATA-1, GATA-2, and GATA-3 in CD34⁺/CD38^lo cells were measured by quantitative RT-PCR analysis. After standardization over GAPDH mRNA levels, results were expressed as percentage of GFP⁺ cells. The mRNA level of every factor was tested at least twice. Error bars indicate standard deviations between measurements. P < .05 for GATA-2 expression.