Survival in different cohorts generated by serial transplantation of Ink4a-Arf–/– BM. (A) Survival of secondary recipients of transplants of 1 × 105 BM cells. The survival curve for recipients of Ink4a-Arf–/– BM is indicated by ▪ and that from recipients of wild-type cells by □. The number of weeks after transplantation is indicated on the x-axis. (B) Survival of tertiary recipients of 1 × 105Ink4a-Arf–/– BM cells. There is no wild-type control because there were not enough healthy surviving mice with wild-type BM cells from the previous transplantation round. (C) Survival of recipient mice in the fourth round of serial transplantation. Mice were given 1 × 106 BM cells from the third-round serial recipients of either Ink4a-Arf–/– BM (▪) or from wild-type BM (□). (D) Apoptotic rates are not changed in primary recipients of wild-type and Ink4a-Arf–/– BM cells. Mice received transplants of 2 × 105 cells from either wild-type or Ink4a-Arf–/– mice, and their BM was analyzed 2, 3, and 4 weeks after transplantation. Cells were stained with Lin-APC-Cy7 antibody cocktail, c-Kit-APC, Sca-PE, and annexin V–FITC antibodies and analyzed by flow cytometry. Annexin V marks apoptotic cells. DAPI (4,6-diamidino-2-phenylindole) was used to mark dead cells. Shown is a representational analysis of apoptotic rates in the KSL fraction of BM cells from recipient mice 3 weeks after transplantation. Other time points were not significantly different and are not shown. Analysis of a wild-type mouse not given a transplant is shown for comparison. Numbers indicate the percentage of cells in each quadrant.
