FIG. 8.

Deletion of SNF1 increases the growth defects and HU sensitivity of the rnr4Δ mutant. (A) Flow cytometry shows that rnr1Δ and rnr4Δ mutants have higher levels of cells in S phase than do the wild-type (WT) controls. Log-phase cells were prepared for flow cytometry as described previously (26). (B) snf1Δ rnr4Δ double mutants are more sensitive to HU than is either single-mutant parent strain. Two independent double-mutant segregants of a meiotic cross are shown. Serial 10-fold dilutions of the indicated strains were spotted onto a YPD plate containing 50 mM HU and incubated at 30°C. Note that the snf1Δ mutant in the BY strain background shown here is less sensitive to HU inhibition than is the same mutant in the MCY strain background used elsewhere in this paper. (C) snf1Δ rnr4Δ double mutants grow more slowly than either single-mutant parent on YPD plates at 30°C incubated for the indicated periods of time at 30°C. Three different snfΔ rnr4Δ double mutants are shown. The WT MATa strain is BY4741, and the WT MATα strain is BY4742. The rnr1Δ, rnr4Δ, and snf1Δ mutant versions of these strains were obtained from the BY yeast gene deletion collection (20).