FIG. 5.

Comparison of the kinetics of RNA synthesis by nsP3 mutant viruses and parental viruses. CEF cells were infected at 30°C (A) with ts4 (•), ts7B5 (▪), ts138 (♦), Toto:ts138AS recombinant (▴), or parental SIN HR (▾) at an MOI of 100 or were mock infected (⋄). Duplicate cultures were shifted to 37°C (B) or 40°C (C) beginning at 1 h p.i. and were maintained at the respective temperatures until the end of the experiment. Cultures were labeled with [³H]uridine (50 μCi/ml) in the presence of 20 μg of actinomycin D/ml for 1-h periods and were immediately harvested at the end of the pulse. The acid-insoluble incorporation in 50,000 cells is shown.