The effect of fractionated irradiation on G0 phase of non-tumorigenic cells and CICs. FACS analysis of G0 phase in the total population, non-tumorigenic cells and CICs, 48 h after the last dose of irradiation. Cell DNA was stained with Hoechst 33342, and the RNA was stained with pyronin Y (PY), and cell fluorescence was analyzed on a flow cytometer. (A) Dot blots of DNA and RNA content. (B) Cells in G0 after 0 and 5 × 3 Gy fractionated irradiation. Data show one representative experiment.