Deletion of Dot1l leads to pancytopenia and bone marrow hypocellularity. (A) H3K79me2 Western blot of bone marrow. Unfractionated bone marrow was harvested from Dot1l^F/F;CreER⁻ or Dot1l^wt/wt;CreER⁺ (Dot1l^+/+) and Dot1l^F/F;CreER⁺ (Dot1l^F/F) mice 3 weeks after tamoxifen injection. Dot1l deletion led to the loss of H3K79 methylation in Dot1l^F/F bone marrow. Histone 3 blot was used as loading control. (B) Survival curve of mice after Dot1l deletion. Dot1l^+/+ and Dot1l^F/F mice were injected with tamoxifen once a month for continuous Dot1l deletion. Dot1l^F/F mice died between 8 to 12 weeks after initial injection. (C) Hematoxylin and eosin-stained section of bone marrow. Dot1l deletion led to bone marrow hypocellularity in Dot1l^F/F mice. Tissues were collected when Dot1l^F/F mice became moribund. Scale bars represent 50μm. Micrographs were obtained using Olympus BX41 microscope, 100×/1.30 oil UPlanFL N lens, and Olympus DP71 camera. (D) Final complete blood counts before Dot1l^F/F mice died or were sacrificed. Data points represent individual animals. Bars represent mean values.