Duck plague virus UL13 hijacks an RNA-binding protein, interferon induced protein with tetratricopeptide repeats 5, to promote replication.

The UL13 protein of the duck plague virus has been identified as a conserved herpesvirus protein kinase crucial for viral infection. However, its interaction with host proteins requires further investigation. In this study, we first constructed and rescued a recombinant virus, DPV-BAC-UL13C⁎3HA, expressing a C-terminally 3HA-tagged pUL13 fusion protein. The protein samples from duck embryo fibroblasts infected at an MOI of 10 with DPV-BAC-UL13C⁎3HA were subsequently enriched with an HA antibody and detected using liquid chromatography-tandem mass spectrometry technology to analyze and plot the interaction network diagram of pUL13. Subsequent experiments using RNA immunoprecipitation, immunofluorescence assay, and co-immunoprecipitation confirmed that the host protein IFIT5 binds to duck plague virus RNA, and that pUL13 interacts with IFIT5 to inhibit this binding. Furthermore, as IFIT5 is an important antiviral factor induced by type I interferon, we also demonstrated that pUL13 suppresses interferon-β production, thereby indirectly inhibiting IFIT5 transcription. Finally, our duck infection experiments demonstrated that the transcription of IFIT5 and IFN-β was increased in ducks infected with the UL13 deletion virus. In summary, pUL13 inhibits IFIT5 recognition and binds to duck plague virus RNA by interacting with the host protein IFIT5 and antagonizing IFN-β production to promote duck plague virus replication.