Activation of the Transcription Factor ISGF3 by Interferon-gamma

Abstract

AbstractThe interferon-stimulated gene factor 3 (ISGF3) transcription factor has been extensively studied in the context of the type I interferon (IFN-α/β)-mediated antiviral response; it consists of the major DNA-binding component p48, and the signal transducers and activators of transcription (Stat)1 and Stat2. We show here that type II IFN (IFN-γ) can also invoke the activation of ISGF3 in mouse primary embryonic fibroblasts. In fact, the two Stat proteins were tyrosine phosphorylated in IFN-γ stimulated cells. Our present findings reveal an additional mechanism by which these two distinct types of cytokines, IFN-α/β and -γ, can commonly elicit antiviral activities.