Unaffected HSC populations in mice treated with Epo. Phenotypic analysis of hematopoietic (A) progenitor and (B) stem cell fractions by FACS using the indicated surface markers (LKS+/−; lineage− ckit+ Sca1+/−). CMP indicates common myeloid progenitor; GMP, granulocyte macrophage progenitor; MEP, megakaryocyte erythroid progenitor; LT-HSC, long-term HSCs; ST-HSC, short-term HSCs; and MPP, multipotent progenitors. n = 12 per treatment. (C) Long-term donor reconstitution and (D) lineage distribution analyzed 16 weeks after competitively transplanting 200 000 unfractionated BM cells from mice treated with either control or Epo, together with 200 000 cells from congenic wild-type mice into lethally irradiated recipients (n = 12 per treatment). Data are mean ± SEM.