ICN1-induced T-ALL develops with delayed kinetics in Rag2^-/- mice.Rag2^-/- mice were reconstituted with Rag2^-/- bone marrow transduced with mICN1-containing or empty retroviruses. Cell suspensions were stained for the expression of CD4 and CD8 markers, and FACS analysis was performed to determine EGFP⁺ percentages in peripheral blood (PB), bone marrow (BM), and thymus (THY) of Rag2^-/- mice reconstituted with Rag2^-/- bone marrow transduced with mICN1-containing retroviruses 2 weeks after BMT (A, top panels), 4 weeks after BMT (B, top panels), and 8 weeks after BMT (C, top panels). Percentages of EGFP⁺CD4⁺CD8⁺ cells from the same samples at 2, 4, and 8 weeks after BMT are also included (A-C, bottom panels). EGFP⁺CD4⁺CD8⁺ cells were never detected in peripheral blood and organs from Rag2^-/- mice reconstituted with Rag2^-/- bone marrow transduced with empty retroviruses (data not shown). Data are representative of at least 3 independent experiments.