H5N1 NS1 expression inhibits IFN-inducible STAT:SIE complex formation.

<p><b>A</b>) HeLa cells transfected with either vector alone or HA-tagged NS1 plasmid were left untreated (−) or treated (+) with IFN-β (1×10³ U/mL) for 15 mins, 24 hr post-transfection. Nuclear extracts were isolated and equal amounts of protein were incubated with ³²P-labeled SIE probe. Complexes were resolved by native gel electrophoresis and visualized by autoradiography. Data are representative of two independent experiments. HeLa cells were treated with IFN-β (1×10³ U/mL) for 15 mins. Nuclear extracts were isolated and equal amount of protein were incubated with ³²P-labeled SIE probe in the presence or absence of 2 µg of anti-STAT1 and anti-STAT3 antibodies, as indicated. Complexes were resolved by native gel electrophoresis and visualized by autoradiography.