Goatpox virus Hrf-063 interacts with host eIF4A1 and is associated with altered expression of antiviral...

Goatpox virus (GTPV) is an important capripoxvirus that causes severe disease in goats, yet the functions of many GTPV-encoded proteins remain unclear. In this study, eukaryotic translation initiation factor 4A1 (eIF4A1) was identified as a host protein interacting with GTPV Hrf-063 by GST pull-down combined with LC-MS/MS analysis. This interaction was further confirmed by reciprocal pull-down assays and co-immunoprecipitation in mammalian cells. Domain-mapping analysis showed that the N-terminal region of Hrf-063 and amino acids 211-330 of eIF4A1 were critical for their interaction, and confocal microscopy demonstrated that both proteins predominantly co-localized in the cytoplasm. Functional analyses showed that Hrf-063 was negatively associated with eIF4A1 expression during GTPV infection, while eIF4A1 modulation affected the expression of the GTPV virulence-associated protein Klp2. In addition, perturbation of Hrf-063 or eIF4A1 altered the expression of STAT1 and CAV1, and Hrf-063 regulated ISG15 and STING1 transcription in a time- and infection-dependent manner. TCID₅₀ assays further showed that altered Hrf-063 or eIF4A1 expression affected infectious GTPV production. Collectively, these findings identify eIF4A1 as a host interaction partner of GTPV Hrf-063 and suggest that the Hrf-063-eIF4A1 axis is involved in viral protein expression, innate immune regulation, and infectious virus production.