Effect of enforced TAL1 expression on the differentiation of SRCs in NOD-SCID mice. (A) Experimental strategy. (B) Engraftment levels measured by the percentage of human CD45⁺ cells in the mouse bone marrow; indicated are median values of 4 independent experiments; the numbers of engrafted mice over the total injected mice are also given. (C) Endogenous and transgenic tal1 mRNA levels measured in the human cells engrafted in 4 NOD-SCID recipients from a representative experiment. Semiquantitative RT-PCR was performed with primers that do not amplify the mouse tal1 cDNA. Human S14 levels are used to control the human engraftment levels in every mouse. (D-E) Human erythroid cell engraftment in the BM of NOD-SCID mice. Cells were labeled with anti-GPA antibody and subjected to FACS analysis. Percentages of GPA⁺ cells in 2 representative mice (D) and in all tested mice (E) are shown (P = .01). (F-G) FACS analysis of the mature human CD19⁺ B cells and CD14⁺/CD15⁺ myeloid cells present among nucleated cells in the BM of NOD-SCID mice. Results from two representative mice are shown (F), and the ratio between CD19⁺ B cells and CD14⁺/CD15⁺ myeloid cells is given for each tested mouse (G). The numbers indicated in panels E and G are median values. Numbers in each FACS quadrant indicate the percentage of positive cells among gated (R1) cells.