cDKO causes loss of HSPCs through apoptotic cell death and loss of repopulating potential in hematopoietic stem cells (HSCs). (A-C) Cell numbers of BM progenitors (A), myeloid progenitors (B), and LTHSCs (C) from 2 hind limbs. (D-E) Frequency of apoptotic cells in LKS⁺ (D) and CD150+ cells (E). (F) Experimental scheme. Whole BM cells from either non-TAM treated WT or cDKO animals (expressing the CD45.2 allele) were mixed with an equal number of congenic whole BM (CD45.1) and injected into lethally irradiated recipients (CD45.1/CD45.2). (G) Peripheral blood was monitored to measure bone marrow chimera establishment in recipient mice on week 4. cDKO was induced in 4 weeks posttransplantation. TAM or vehicle control was administered, and the percentage of donor chimerism was measured at indicated time points. Statistical analysis represents t test or 2-way analysis of variance (ANOVA). Each point represents an individual mouse/biological replicate. See also supplemental Figure 2. *P < .05. **P < .01. ***P < .001. ****P < .0001. IR, irradiated.