FIG. 6.

Replication of chimeric DI RNAs containing exchanges of the SV5 and HPIV2 antigenomic 3′ ends. (A) Schematic representations of chimeric SV5-HPIV2 DI RNAs. Cross-hatched boxes indicate the termini of the DI RNAs, with white and dark-shaded boxes representing SV5- and HPIV2-specific sequences, respectively. The predicted sizes of the DI RNAs are listed, along with the relative replication level expressed as a percentage (±SD) of that determined for DI852 (SSS) analyzed in parallel. (B) Replication of the chimeric DI-SSP RNA requires L, P, and NP proteins. vTF7.3-infected A549 cells were cotransfected with the SV5 L, P, and NP plasmids along with DNA encoding either the DI852 genome (lane 1) or the chimera DI-SSP (lane 2). Total intracellular RNA was harvested and analyzed by Northern blotting using a positive-sense SV5-specific ³²P-labeled riboprobe as described in the legend to Fig. 1. Lanes 3 to 5 are samples from cells in which the indicated support plasmids were replaced with pGem control DNA. The arrow indicates the position of genome-length DI852 RNA. (C) Replication of the SV5-HPIV2 chimeric antigenome requires sequences contained within HPIV2 CRII. A549 cells infected with vTF7.3 were transfected with the L, P, and NP plasmids along with DI852 plasmid (SSS; lane 1), DNA encoding the chimera with HPIV2 sequences at the 3′ terminus (SSP; lane 2) or at the 5′ terminus (PSS; lane 3), or a modified DI-SSP RNA in which HPIV2 CRII sequences had been deleted (SSPt; lane 4). Total intracellular RNA was harvested and analyzed by Northern blotting as described above.