Various lineage progenitors were reverted into the primordial lineage of phagocytes by Ring1a/b KO. (A) DN3 cells, pro–B cells, ErPs, and MkPs isolated from Ert2Cre-Cdkn2a^−/−Ring1a^−/−Ring1b^fl/fl mice were cocultured with TSt4 or TSt4-DLL1 cells for 4 to 12 days with or without 4-OHT in the presence of 10 ng/mL of stem cell factor, Flt3-L, interleukin 1α (IL-1α), IL-3, IL-7, tumor necrosis factor α, and granulocyte-macrophage colony-stimulating factor. For ErPs and MkPs, 2 U/mL of erythropoietin and 50 ng/mL of thrombopoietin were added, respectively. (B) Flow cytometric profiles of the cultured cells. Data are representative of 3 independent experiments. (C) Cytology of the generated CD11b⁺ cells was examined by Wright-Giemsa staining (left), and their phagocytic activity was evaluated by pHrodo-green beads with CD11b-BV421 staining (right). (D) Expression levels of Ring1A/B homologs in Capsaspora and various mouse cell lineages. (E) Heat map with Pearson correlation of mouse normal and Ring1a/b KO myeloid cells and Capsaspora.