Increases in apoptosis and in the proportion of cells in S/G2/M in bone marrow of STAT5A/5B-deficient mice.

Whole bone marrow from the indicated mice was stained for apoptosis or DNA content measurements in conjunction with antibodies to lineage markers and Sca-1. (A) Percentage of apoptotic cells in the lin⁺ (P = .04), lin^dimSca-1^neg/lo post-HSC progenitors (P = .03), and lin^dimSca-1⁺ HSC (P = .04) subsets in STAT5A/5B^−/− and STAT5A/5B^+/+ mice are shown. (B) Percentage of cells with more than 2n DNA content for the lin⁺(P = .2), lin^dimSca-1^neg/lopost-HSC progenitors (P = .01), and lin^dimSca-1⁺ HSC (P = .005) subsets are shown.