Chicken interferon regulatory factor 1 (IRF1) involved in antiviral innate immunity via regulating IFN-β production

Interferon regulatory factors (IRFs) is an important family for IFN expression regulating while viral infection. IRF1, IRF3, and IRF7 are the primary regulators that trigger type I IFN response in mammals. However, IRF3, which has been identified as the most critical regulator in mammals, is absent in chickens, and it is unknown whether IRF1 is involved in type I IFN signaling pathways in IRF3-deficient chicken cells. Here, we identified chicken IRF1 (chIRF1) as a critical IFN-beta mediator in response to viral infection. Overexpression of chIRF1 activated IFN-beta intensively and suppressed AIV and NDV viral replication. Moreover, the mRNA levels of IFN-beta and ISGs increased during chIRF1 overexpression. In addition, deletion mutant analysis revealed that the first four domains of chIRF1 are indispensable for IFN-beta induction. Together, our studies demonstrate that chIRF1 is an important regulator of IFN-beta and is involved in chicken antiviral innate immunity.