Stabilization of HIF1α induces proliferation of PHD2-deficient LSK cells. (A) Cell-cycle analysis of LSK cells from WT and cKO BM. The lower gate (Ki67^−ve) contains cells in the G0 phase of the cell cycle, the top left represents cells in the G1 phase, and the top right represents cells in S/G2/M phases. cKO mice show less quiescent (G0) LSK cells under steady-state conditions compared with their WT littermates (n = 4). (B) Annexin⁺ apoptotic cells in WT and cKO LSK cells. (C-E) The absolute numbers of (C) BM and (D) LSK cells in WT mice and their cDKO (CD68:cre-PHD2/HIF1α^ff/ff) littermates, (E) subsequently subdivided in the 5 HSC/MPP subsets. No difference was detected in BM, LSK, or any of the subsets (n = 7-8). (F) Expression profile (qRT-PCR) of different genes in LSK cells of WT and cDKO mice (n = 3-4). All data are mean ± SEM. **P < .01. Abs. cell n°, absolute cell number; i.c., intracellular.