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

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. TCID 50 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.