IFN-γ and IL-6 induce prolonged activation of STAT3 in STAT1^–/– mouse hepatocytes. Primary cultured mouse hepatocytes were treated with IFN-γ (10 ng/ml) or IL-6 (20 ng/ml). At various time points, as indicated, cell protein extracts and RNA were prepared and analyzed by Western blotting and RT-PCR (indicated by asterisks), respectively, using Ab’s or primers as indicated. Similar data were obtained from five independent experiments.