Engraftment studies using cultured BM cells from Arf^–/– or Ink4a-Arf^–/– mice. (A) CR analysis of peripheral blood cells derived from recipients of transplants of cultured BM cells from Arf^–/– mice (□) or from wild-type mice (▦). BM cells were grown in culture for 12 days and competed against fresh wild-type Ly5.1 BM cells. These data were obtained at analysis at 10 weeks after transplantation and were essentially unchanged over time up to 24 weeks. Graph shows the percentage of Ly5.2 cells in myeloid and lymphoid lineages. As before, myeloid cells were defined by the Gr1⁺/Mac1⁺ phenotype and lymphoid cells by the Gr1^–/Mac1^– phenotype. (B) CR analysis of peripheral blood cells derived from recipients of transplants of cultured BM cells from Ink4a-Arf^–/– mice (□) or from wild-type mice (▦). The experiment was done as described in panel A. These data were obtained by analysis at 12 weeks after transplantation and were essentially unchanged over time up to 24 weeks.