Figure 2.

pI215L colocalizes with STAT2 at the nucleus. (A) hSTAT2-FLAG interacts with pI215L in BSRT7 cells. BSRT7 cells were co-transfected with hSTAT2-FLAG (0.4 μg/1 × 10⁶ cells) and with pIRES-I215L-myc (2 μg/1 × 10⁶ cells). 24 h post-transfection, cells were stimulated with Universal Type I IFN (500 U/mL) for 1 h. Cells were then collected and processed for immunoprecipitation with an anti-myc antibody and analyzed by Western blot labeling with antibodies against FLAG to detect STAT2, against myc to detect pI215L and against actin. (B) pI215L colocalizes with STAT2 in the cell nucleus. Vero cells were transfected with EV or pIRES-I215L-myc (2 μg/1 × 10⁶ cells) expression plasmids. After 24 h, cells were stimulated with IFN-I (250 U/mL) for 1 h. After treatment, cells were fixed and stained with DAPI (blue), anti-STAT2 (green) and anti-myc (I215L; red) antibodies and examined by a confocal microscope. Merged images of the different channels are also shown.