Gdf15 signaling is required for erythroid short-term radioprotection following bone marrow transplant. Analysis of short-term radioprotection by WT or Gdf15^−/− bone marrow cells following transplant into lethally irradiated recipients. (A) Survival curve with P < .001 (Gehan-Breslow-Wilcoxon test). Data are representative of 4 individual transplants with total n = 9 for WT and n = 16 for Gdf15^−/−. (B) Hematocrit levels during the recovery period. Each time point reflects >5 mice analyzed. Data are shown as the mean ± SEM. (C-E) Donor mice were CD45.2 and recipient mice were CD45.1. Spleens were isolated at day 8 and day 10 post-BMT for analysis. (C) Analysis of the proliferation of cell in the spleen following transplant, spleen weight (left), and total cell number (right) on the indicated days after transplant are shown. (D) Analysis of donor cell proliferation, total CD45.2⁺ donor cells (left), Kit⁺Sca1⁺ progenitors (middle), and CD34⁺CD133⁺Kit⁺Sca1⁺ progenitors (right) in each spleen. (E) Number of stress BFU-E in the spleen on the indicated days after transplant. Each time point reflects >3 mice analyzed. Data are shown as individual subject and the mean ± SEM. *P < .05, **P < .01, and *** P < .001.