“Birds do it their way: avian interferon regulatory factors (almost) resolved”
Interferon regulatory factors (IRFs) are transcription factors that play a key role in vertebrate innate antiviral immunity. IRF3 and IRF7 activate the expression of IFN-β, which in response induces the assembly of STAT1, STAT2 and IRF9 into the ISGF3 complex. Subsequently, this complex activates the expression of interferon-stimulated genes (ISGs) mounting the antiviral state of the cell. Interestingly, IRF9 and IRF3 have been reported to be missing in birds. As part of our efforts to search for hidden genes in avian genomes, we have identified IRF3 in paleognathous birds and IRF9 in most bird orders with the notable exception of the chicken. We focus on the experimental characterization of IRF9 in a duck cell line and also look for a possible substitute for IRF9 in chickens.