FIG. 2.

Rescue of transfectant virus using the novel transfection protocol. (A) WSN RNP (10 μl) was treated with 1 or 2 μg of NS cDNA fragment in the presence of 0.4 M NaCl for 5 min at 37°C; then it was diluted and treated with 30 U of RNase H for 5 min at 37°C as described in Materials and Methods. The purified RNA was loaded onto a 3.2% polyacrylamide gel containing 7.7 M urea and visualized by silver staining as described previously (6). An asterisk indicates one of the shorter bands which may be digested fragments. (B) The NS-digested RNPs were transfected into MDBK cells with or without reconstituted NS RNP. Viral plaques were formed by infectious center assay. 3Ps, PB1, PB2, and PA.