Induction of IRF7 by treatment or transfection of our bat kidney cell line with the dsRNA ligand, polyI:C resulted in a peak in the induction of IRF7 at 9 h post-treatment, which is 3 h later than the peak in bat type I and type III IFNs but similar to that of ISGs Mx1, OAS1 and PKR described previously in bat cells. This Famprofazone result is consistent with the induction of IRF7 through type I IFN feedback similar to other species. In humans, IRF7 is generated through multiple pathways following IFN induction. Following the production of IFN and binding to the IFN-aR, a complex consisting of activated STAT1, STAT2 and IRF9, called the IFN stimulated gene factor 3 is formed, which in turn binds to the ISRE on the IRF7 promoter and induces IRF7 transcription. The human IRF7 promoter region contains an NF-kB binding site and a single functional ISRE approximately 1.3-kb upstream from the ATG start site, both of which are important in the induction of IRF7. Analysis of the putative bat IRF7 promoter region resulted in the identification of two ISREs and one NF-kB binding site indicating that multiple mechanisms for IRF7 activation may also exist in bats. However, two ISRE sites were also identified in the IRF7 promoters of other species examined. Thus, whether the broad distribution of constitutively expressed IRF7 is the result of the presence of a more efficient IRF7 promoter region driven by transcription factors other than IRFs, or simply due to enriched immune-related cells in all tissues will require further study. Sequence differences in the MyD88 binding domain of bat and human IRF7 led to the hypothesis that there may be functional differences in the activation of bat IRF7 and the regulation of the IFN response that may contribute to the ability of bats to resist the clinical outcomes of viral infection. Our results demonstrate that these sequences differences do not appear to affect IRF7 function either in IFN transactivation activity or activation by MyD88. Bat IRF7 was Dimaprit dihydrochloride capable of activating both IFN-a and IFN-b promoters and the levels of transactivation were equivalent to or higher than that of human IRF7. Similarly, bat MyD88 and bat IRF7 maintained binding capability similar to their human counterparts.