Table 3.
Effect of synonymous mutations in the PB2-coding region on segment 1 packaging
| vRNAa | Mutation | MPD score | Packaging levels (% of GFP-expressing cells)b | vRNA expression levels (% of PB2(159) GFP(166))c |
|---|---|---|---|---|
| PB2(159) GFP(34) | n/a | n/a | 0.4 ± 0.1 | 130 ± 10 |
| PB2(159) GFP(166) | n/a | n/a | 27.5 ± 7.3 | 100 |
| mut 731 | GUG -> GUC | 0.360 | 18.5 ± 1.6 | 20 ± 0 |
| mut 737 | CGG -> CGC | 0.539 | 17.9 ± 4.4 | 35 ± 5 |
| mut 744a | CUU -> CUA | 0 | 0.8 ± 0.2 | 80 ± 20 |
| mut 744b | CUU -> UUA | 0 | 0.5 ± 0.1 | 65 ± 5 |
| mut 745 | ACU -> ACA | 0 | 1.2 ± 0.3 | 55 ± 5 |
| mut 748 | CAG -> CAA | 0 | 1.1 ± 0.3 | 75 ± 25 |
| mut 751 | ACC -> ACG | 0.008 | 0.5 ± 0.3 | 110 ± 10 |
| mut 757 | GCC -> GCG | 0 | 1.1 ± 0.4 | 70 ± 10 |
aPB2(159)GFP(166) denotes vRNAs containing PB2 codons 1–44 and 716–759 (synonymous mutations introduced as indicated), while PB2(159)GFP(34) refers to a vRNA lacking all 3′-PB2-coding regions.
bMean ± standard deviation of four measurements from two independent clones.
cMean ± range from two independent clones as determined by primer-extension analysis. n/a, not applicable.