FIG. 1.

Combination of mutations in PB1 and PB2 provides attenuation to the polymerase complex of a swine influenza virus strain. (A) Schematic representation of the polymerases att, ts, and the wt. (B) Scheme of the minigenome GFP reporter assay. (C) Pictures from the minigenome assay with the att, ts, and wt polymerases at different temperatures. Numbers below the pictures indicate the number of cells expressing GFP as percentages relative to the maximum and minimum number of fluorescence units. (Numbers reflect data from the experiment shown here. Two other experiments have been performed, with similar results.)