Fig 8.

The E2 Y18H mutation reduces the infectivity of RRV in a cell-type-dependent manner. C2C12 murine muscle cells were inoculated with GFP-expressing RRV-T48 or RRV-T48 E2 Y18H at an MOI of 5. (A and B) RRV RNA copies (A) and PFU present in clarified C2C12 culture supernatants (B) were quantified by qRT-PCR and plaque assays, respectively. Each data point represents an individual cell culture. Data were analyzed for statistically significant differences by two-tailed t tests with Welch's correction. (C to H) RRV-T48 and RRV-T48 E2 Y18H were grown in C2C12 cells and BHK-21 cells. Clarified cell culture supernatants were analyzed directly (C to E), or virions were purified through a 60% to 20% discontinuous sucrose gradient prior to analysis (F to H). PFU (C and F) and RRV RNA copies (D and G) were quantified by plaque assays and qRT-PCR, respectively. The genome-to-PFU ratios were calculated based on the number of genomes/ml and the number of PFU/ml present in culture supernatants of gradient-purified virus stocks (E and H).