In vivo modeling of functional cooperation between AEL-associated alterations. (A) Experimental design: mouse CD45.2⁺ HSPCs from WT, G1s, Tet2^−/−, or Tet2^−/−+ G1s mice were sorted and injected into sublethally irradiated CD45.1⁺ recipients followed for disease development. (B) Kaplan-Meier plot of diseased recipients of HSPC cells from Tet2^−/− (n = 5) or Tet2^−/−+G1s (n = 5) mice. (C) Peripheral blood counts (WBC, RBC, and PLT) of immunodeficient mice engrafted with HSPC cells from Tet2^−/− (n = 5) or Tet2^−/−+G1s (n = 5) mice. (D) Flow cytometry analysis of myeloid cells (Gr1⁺CD11b⁺), erythroid progenitors (CD71⁺ Ter119⁺), B cells (B220⁺), and T cells (CD4⁺CD8⁺) gated for CD45.2⁺ donor cells from Tet2^−/− or Tet^−/−+G1s mice. (E) Experimental design: HSPCs from WT or TP53^R248Q mice were retrovirally transduced with ERG or an empty vector (Ctrl), containing both an IRES-GFP expression cassette, and transplanted into WT primary recipients. Top, Primary recipients of ERG-transduced cells developed T-ALL (supplemental Figure 6). Bottom, to investigate cooperation specifically in erythroid progenitors, ERG-expressing erythroid progenitors (GFP⁺CD71⁺Ter119⁺KIT^low/+) were sorted from primary recipient mice and transplanted into secondary recipients to follow disease development. (F) Kaplan-Meier plot of diseased secondary recipient mice (described in panel A). WT (Ctrl or ERG): n = 4, TP53^R248Q (Ctrl or ERG): n = 6. (G) Peripheral white blood cell (WBC), red blood cell (RBC), and platelet (PLT) counts of diseased mice transplanted with WT or TP53^R248Q HSPC retrovirally transduced with ERG or empty vector (Ctrl). WT (Ctrl or ERG): n = 4, TP53^R248Q (Ctrl or ERG): n = 4. (H) Flow cytometry analysis of myeloid cells (CD11b⁺Gr-1⁺), erythroid progenitors (CD71⁺Ter119⁺), B cells (B220⁺), and T cells (CD4⁺CD8⁺) from diseased secondary recipients of TP53^R248Q HSPCs retrovirally transduced with ERG gated for GFP⁺ or GFP⁻ cells. Statistical significance (in panels B, C, F, and G) is indicated as P values (Student t test except when otherwise specified). *P < .05; **P < .01; ***P < .001.