FIG. 1.

Poly(A)⁺ (A) and poly(A)⁻ (B) RNA synthesis in BHK cells infected with wt, tsO82, and v6 viruses. BHK cells were infected with wt (open circles), tsO82 (closed squares), and v6 (closed triangles) viruses at a multiplicity of infection of 20 PFU/cell. Parallel samples were infected in the presence of actinomycin D. At 2, 4, and 6 h postinfection, cells were labeled with [³H]uridine (20 μCi/ml) for 30 min. Cells were harvested and lysed in SDS lysis buffer. To separate poly(A)⁺ and poly(A)⁻ RNAs, lysates were incubated in the presence of oligo(dT) cellulose (Invitrogen), washed in high-salt buffer, and eluted in low-salt buffer. Samples were then precipitated with 7% trichloroacetic acid on ice and washed twice with 7% trichloroacetic acid. Acid-precipitable radioactivity was measured by scintillation counting. Values of samples incubated in the presence of actinomycin D were subtracted from the total counts to determine the rate of host RNA synthesis. Data shown are means ± standard deviations for four experiments.