Regulation of the interferon system, immune response and oncogenesis by the transcription factor interferon regulatory factor-1.

Interferon regulatory factor-1 (IRF-1) is a transcriptional activator which was originally identified as the regulator of the type I interferon (IFN-alpha/beta) gene expression. Subsequent studies have revealed that IRF-1 is involved in a wide spectrum of the host defense mechanisms, including the antiviral response by IFNs. IRF-1 has also been shown to regulate a variety of cytokines and their target genes, thereby contributing to the development and function of the Th1-type immune response. Furthermore, IRF-1 is a critical regulator of cell growth and death, and its inactivation accelerates cell transformation. IRF-1 may be a prototypical example of a transcription factor which can selectively modulate distinct sets of genes depending on the cell type and/or nature of the cellular stimuli, so as to evoke appropriate response in each.