FIG. 5.

Comparison of specific infectivity, RNA replication, protein synthesis, and virus production in cells transfected with genome-length RNA containing K-D-K-E mutations. Equal amounts of wild-type and mutant genome-length RNAs were transfected into BHK cells and assayed for specific infectivity (A). At indicated time points, viral RNA replication, protein expression, and virus production were monitored by real-time RT-PCR (B), IFA (C), and plaque assay (D), respectively. For specific infectivity, an average result of four independent experiments is shown (A). One representative result of two independent experiments is shown for real-time RT-PCR (B), IFA (C), and viral yield production (D). Viral RNA synthesis (B) is presented as RNA copy number per 100 ng of total cellular RNA, using full-length WNV RNA transcribed from an infectious cDNA clone (38) as a reference. Virus production (D) in the supernatants of transfected cells was quantified by plaque assays on Vero cells.