MCL-1 is essential for recovery of the hematopoietic system from sublethal γ-irradiation. (A) Mice (wild-type or Mcl-1+/−) were subjected to 8 Gy γ-irradiation and their survival monitored (median survival of Mcl-1+/− mice: 11 days; log-rank [Mantle-Cox] test, P < .0001); n = 14 (wild-type), 10 (Mcl-1+/−) mice. Pooled results from 2 independent experiments are shown. (B) Histologic analysis of the bone marrow of wild-type and Mcl-1+/− mice was performed 12 days after γ-irradiation. Representative hematoxylin and eosin (H&E)-stained bone marrow sections (×20 objective, 500 µm scale bar).