FIGURE 4.

Mms21 may function through the sumoylation of Smc5 to prevent rapid senescence. A and B, senescence assays performed at 30 °C comparing the senescence rate of tlc1Δ smc5-6 and tlc1Δ smc6-9 mutants versus tlc1Δ controls. Each data point represents the mean ± S.E. (error bars) of six independent spore colonies. C and D, spot assay performed at 30 °C comparing the growth rates of uba2-ts10 and mms21-sp mutants alone or in combination with smc5-6 and smc6-9 alleles. For spot assays, 100,000 cells, and 10-fold serial dilutions, were grown on YPAD plates. WT, wild type.