In committed adult EPs, differentiation toward the myeloid lineage is actively repressed by the chromatin-modifying enzyme LSD1. If LSD1 is depleted or inactivated pharmacologically, the cells convert to GMPs characterized by increased expression of the myeloid-specifying gene Pu.1. CMP, common myeloid progenitor; MEP, megakaryocyte-erythroid progenitor. See Figure 5F in the article by Yu et al that begins on page 1691.