Expression of ΔbTAL1 mutant protein interferes with the SRC activity. (A-B) Engraftment levels in the BM of NOD-SCID mice that received a transplant with GFP- and ΔbTAL1-transduced cells. (A) Percentages of human CD45⁺ cells in the bone marrow of 2 representative NOD-SCID mice that received a transplant intravenously 14 weeks before with GFP- and ΔbTAL1-transduced CD34⁺ cells. (B) Summary of the results of 4 independent experiments. The ratios of positive to total injected mice and the median value of the percentage of CD45⁺ cells for each group of mice are indicated. (C) Human cell engraftment levels obtained from mice that received a transplant by intrabone injection with GFP-, TAL1-, and ΔbTAL1-transduced cells. Shown are the percentages of human CD45⁺ cells detected in the injected bone (left) and in the noninjected side bones (right). Engraftment levels were analyzed 2 (1 experiment) and 13 weeks (2 experiments) after transplantation. Median percentages of CD45⁺ cells are indicated as well as the number of tested mice. (D) Phenotypic analysis of the human cells detected in the BM of intrabone injected NOD-SCID mice. GFP-, TAL1-, and ΔbTAL1-transduced cells were recovered from all the bones of individual NOD-SCID mice and analyzed by FACS for the presence of CD19⁺ cells and CD15⁺ cells. Shown are the results of 3 representative mice. Numbers indicate the percentage of positive cells in a gated population. (E) Transgenic TAL1 and ΔbTAL1 expression and vector integration measured by semiquantitative PCR analysis in human cells purified from the BM of 4 mice that received a transplant by intrabone injection with TAL1 (mice 1 and 2) and ΔbTAL1 (mice 3 and 4) transduced CD34⁺ cells. Primers used in RT-PCR were designed to amplify both TAL1 and ΔbTAL1.