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. 2019 Jul 2;15(7):e1007919. doi: 10.1371/journal.ppat.1007919

Fig 1. Polymerase activity of zoonotic avian influenza viruses in human cells.

Fig 1

Viral polymerase activity was measured by minigenome assays in human 293T cells. (A) Polymerase activity of zoonotic avian influenza viruses at 33°C. The data are expressed relative to the results for G1/1997 (H9N2). (B) Polymerase activity at 33°C of reassorted polymerase complexes composed of one subunit from EG/2013 (H9N2) and the other subunits from ancestral G1/1997 (H9N2). The data are expressed relative to the results for EG/2013-wt. (C) Western blot analysis of reassortant polymerase complexes shown in B without (Input) and with (IP: PB2-flag) immunoprecipitation with PB2-flag. Representative images are shown. (D) Polymerase activity of PB2-K627E revertants from EG/2007 (H5N1) and Sh/2013 (H7N9), and of the PB2-V627E revertant from EG/2013 (H9N2) at 37°C and 33°C. (E) Polymerase activity of the PB2-V627K mutant from EG/2013 (H9N2) at 37°C and 33°C. The values of the fold reduction relative to wild-type (D) and to the PB2-V627K mutant (E) are shown. (F) Quantification of PB2 expression levels in 293T cells. The cells were transfected with plasmids expressing the indicated non-tagged PB2, and cell lysates were analyzed by western blotting using anti-PB2 antibody. Representative images are shown. Each data point is the mean ± SD of three independent experiments. Asterisks indicate a P value < 0.01. NS indicates no statistically significant difference.