Figure 3 .

Checkpoint-defective alleles of mrc1 suppress dia2Δ MMS sensitivity and checkpoint recovery defects. (A) mrc1 mutant alleles suppress dia2Δ MMS sensitivity. Tenfold serial dilutions of the indicated strains were spotted on YPD or YPD + 0.007% MMS and incubated at 30°. (B) Checkpoint-defective mrc1 alleles enhance viability of dia2Δ in MMS. Equal numbers of cells were plated on media containing the indicated amounts of MMS, and colony-forming units were counted after 4 days at 30°. Error bars represent standard deviations from three independent experiments. (C) mrc1_1–971 does not suppress pph3Δ MMS sensitivity. Tenfold serial dilutions of the indicated strains were spotted on YPD or YPD + 0.01% MMS and incubated at 30°. (D and E) Checkpoint-defective mrc1 alleles accelerate dia2Δ checkpoint recovery. Cells were arrested in late G1 by α-factor, (D) released into YPD + 0.033% MMS for 40 min, and then released into YPD or, (E) released into YPD at 30°. 1C and 2C indicate DNA content. (F) mrc1_1–971 and mrc1_AQ accelerate Rad53 deactivation of dia2Δ. Cells were arrested in G1 by α-factor, released in YPD + 0.009% MMS for 1 hr, and then released into YPD + 15 μg/ml nocodazole. Protein samples were taken as indicated. Rad53-P and Rad53 represent phosphorylated and unphosphorylated Rad53 proteins, respectively. The very top modified band of Rad53 was quantified using ImageJ and the percentage of that in each time point relative to time zero is shown in the graph.