FIGURE 8.

Epistatic relationship of Rad54 and Mus81. Sensitivity of wild type (WT), mus81Δ, rad54Δ, and double mutant cells to DNA-damaging agents was assayed by growth on plates containing the indicated concentrations of CPT (A) or HU (B). YPD, yeast extract/peptone/dextrose. C, representative maximum intensity projection image of CPT-induced Mus81-yellow fluorescent protein (YFP) foci (indicated by arrows). Images were captured 5 h after treatment. Scale bar, 3 μm. DIC, differential interference contrast. D, quantification of Mus81 foci in RAD54, rad54Δ, rad54-K341A (rad54-K/A), and rad54-K341R (rad54-K/R) genetic backgrounds. IR-treated cells were examined for foci 3 h after treatment. CPT-treated cells were examined 5 h post-treatment. Bars indicate the frequency of Mus81 foci observed in S phase or G₂/M cells (Budded cells). Error bars depict the binomial S.E. Significance from the wild type was determined by a χ² test.