Figure 3.
The SSA1 and SSA2 genes are redundantly required for normal survival and G2/M-checkpoint regulation after DNA damage. (A) Drop-test analysis of the strains indicated irradiated with ultraviolet light at the doses indicated. (B) G2/M-checkpoint analysis of the strains indicated after irradiation with ultraviolet light (50 J m−2) of exponentially growing cells. For clarity, the non-irradiated controls (−UV) are shown in a separate panel. (C) Western blot analysis of Rad9 and Rad53 at 60 min after irradiation with ultraviolet light (60 J m−2) in the strains indicated. (D) Western blot analysis of the kinetics of Rad9 hyperphosphorylation and Rad53 phosphorylation after irradiation with ultraviolet light (50 J m−2) in wild-type (WT) and ssa1Δ/ssa2Δ cells. Samples taken prior to irradiation and immediately after irradiation are indicated as −0 and +0. Note that serum specific to unphosphorylated Rad9 and Rad53 was used. The extent of mobility shift, as well as the reduction in signal, is indicative of the extent of modification.