Increased self-renewal of Sca1⁺/lin^-HSCs expressing X-RARαs. (A) Replating efficiency of Sca1+/lin- stem cells transduced with PML/RARα or PLZF/RARα. Mock-transduced cells were used as control. The cells were seeded in semisolid medium. At day 10 the cells were harvested, analyzed, and replated (I-V indicate the number of the plating round). (B) Surface marker expression of PML/RARα or PLZF/RARα expressing cells of the third plating. Gr-1 and Mac-1 were detected as markers of myeloid differentiation and Sca1 and c-kit were detected as stem cell markers. (C) Cell cycle analysis of 32D cells expressing PML/RARα or PLZF/RARα. Mock-transduced cells were used as control. Cell cycle was analyzed 36 hours after transduction by staining with propidium iodide (PI).