Figure 6.—

Effects of WTM1 and WTM2 dosage on RNR2 and RNR1 reporter expression. Cells containing high-copy RNR2 or RNR1 reporter plasmids were grown in selective medium to midlog phase, incubated with or without 100 mm HU, and then assayed for β-galactosidase activity. (A) Effect of high-copy WTM1/2 plasmid compared to empty vector at 4 hr incubation. Values indicate mean and standard deviation of four independent isolates; effect of pWTM1/2 is statistically significant only for a twofold increase in the RNR2 reporter in untreated cells, P = 0.03. (B) Wild-type or wtmΔ12 deletion strains were assayed for β-galactosidase activity after 3 hr incubation. Values indicate mean and standard deviation of four independent isolates: for the RNR1 reporter, P < 0.001 for effect of wtmΔ12 in both treated and untreated cells; for the RNR2 reporter, P = 0.02 for effect of wtmΔ12 on HU response. Strains used: (A) TSR2147, TSR2148, TSR2150, and TSR2151; (B) TSR2167, TSR2170, TSR2169, and TSR2172.