FIG 3.

PA protein from pandemic H1N1 virus increases the polymerase activity of H7N3 in human 293T cells. (A) A reporter assay was used to measure the relative levels of polymerase activity of different polymerase protein complex combinations between H7N3 and _PH1N1 viruses, including _PH1N1 PA P₂₉₅L, as described in Materials and Methods. The relative polymerase activity data were first normalized to the Renilla activity and compared to that of a full set of H7N3 polymerase proteins. Blue boxes represent H7N3 proteins, white boxes represent pH1N1 proteins, and spotted white boxes represent pH1N1 PA-P₂₉₅L. Data represent the average normalized values from three or five experiments performed in duplicate (**, P < 0.01; ***, P < 0.005 [compared to H7N3 values]).