FIG. 6.

Spontaneous DNA damage occurs during S phase in swi3Δ cells. (A) Multiple Rad22-YFP foci accumulated in swi3Δ cells. Log-phase cells were grown in Edinburgh minimal medium at 25°C. In wild-type cells, 15.8% of the nuclei contained a single Rad22-YFP focus and none showed multiple Rad22-YFP foci. In swi3Δ cells, 65.6% of the nuclei contained at least one Rad22-YFP focus and 48.9% had multiple foci. (B) Quantification of Rad22-YFP foci according to cell cycle stage estimated from cell and nuclear morphology. The percentages of nuclei that have at least one focus or two or more foci are shown. S-phase cells had the most Rad22-YFP foci.