Figure 9

The polymerase activities of wild-type viruses, re-assortant viruses and mouse-adapted viruses at 33 and 37 °C. 293T cells were transfected with plasmids expressing PB1, the NP of 99-H9N2 (A), SD6-H9N2 (B), PG/S1421-H7N9 (C), HK-H1N1 (D), CAL04-H1N1 (E) and WSN-H1N1 (F) and wild-type or MA#12 PB2 and PA proteins at 33 ℃ and 37 ℃, and the polymerase activities were determined. During transfection, WSN NA-firefly and pRL-TK plasmids were transfected simultaneously. The data presented are the mean ± SD of three independent experiments. P values were calculated by using the Student’s t test, *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.