Flow cytometry distributions of total erythroblasts according to the apoptosis status and the phase of the cell cycle.

Folate-deficient erythroid cells (FDCs) were cultured for 32 or 44 hours in folate-deficient medium (FDM) or control folate-replete medium (CM). The fixed cells were labeled with FITC-dUTP via the TUNEL method and stained for total DNA with propidium iodide (PI). In column 1, each histogram is divided into brightly fluorescent, TUNEL positive, apoptotic cells and faintly fluorescent, TUNEL negative, nonapoptotic cells. In columns 2, 3, and 4, the distribution of PI fluorescence is shown for the total, apoptotic, and nonapoptotic cell populations, respectively. In column 2, the distribution of the modeled cell cycle phases are shown: G0/G1phase, solid peak of least PI fluorescence; S phase, hatched peak of intermediate PI fluorescence; and G2/M phase, the solid peak of greatest PI fluorescence.