Pyronin Y staining for SP- and MP-CD34^-KSL cells. Pyronin Y staining was performed to detect cells in the G0 phase. BM cells were immunostained with a combination of antibodies as well as stained with Hoechst 33342 and Pyronin Y, and then were analyzed by flow cytometry. (A) CD34⁺KSL cells are shown. (B) SP-CD34^-KSL cells are shown. (C) MP-CD34^-KSL cells are shown. The dotted lines separating the G0 phase from the G1 phase were tentatively set according to intensities of Pyronin Y fluorescence in cells in the S/G2/M phases.