Figure 1. Viral RNA polymerase activity of SC_WT, SC_PA-A36T and SC_PB2-H357N in 293T cells cultured at different temperatures.

Luciferase-based minigenome reporter assays were used to measure polymerase activity in 293T cells at 33, 37, or 39°C. Cells were co-transfected with Gluc reporter plasmid and expression plasmids PB1 and NP, PA, and PB2 (WT or PA-A36T, PB2-H357N mutants) to generate different viral RNPs. After culturing at 33, 37, or 39°C for 24 h, Gaussia luciferase production was measured. Results are presented as mean ± SEM and are representative of three determinations. **, p<0.001, as determined by t-test.