Murine Stat2 is uncharacteristically divergent

Characterization of the ability of human interferons (IFNs) to rapidly indu ce genes led to the identification of the first two members of the STAT (si gnal transducers and activators of transcription) family, Stat1 and Stat2, To study the unique role of this transcription factor in IFN signaling unde r more physiological conditions, murine Stat2 was isolated and found to be surprisingly divergent. This divergence was most striking in the C-terminal transcriptional activation domain. Studies on murine Stat2 indicate that i t functions in IFN signaling. This includes IFN-alpha-dependent activation, nuclear translocation, DNA binding and activation of reporter genes. Howev er, the profound divergence at the C-terminus suggests that murine Stat2 ma y have evolved to mediate some unique functions as well. To explore this po ssibility, proteins that interact with the C-termini of murine and human St at2 were examined. These studies indicate that the murine and human C-termi ni interact with an overlapping, but distinct set of proteins.