DTMUV upregulates DDX17 expression to facilitate viral replication.

Duck Tembusu virus (DTMUV) is a single-stranded positive-sense RNA virus that poses a serious threat to the poultry industry, and its infection mechanism remains incompletely understood. This study aimed to investigate the role of the host protein DDX17 (DEAD-box RNA helicase 17) in DTMUV infection. Utilizing an in vitro infection model combined with CRISPR/Cas9 gene knockout, siRNA interference, and overexpression techniques, we found that DTMUV infection significantly upregulated both mRNA and protein expression levels of DDX17 in host cells. Furthermore, DDX17 facilitated viral replication through its ATP-binding and hydrolysis domain. Co-immunoprecipitation and mass spectrometry analysis confirmed an interaction between DDX17 and the DTMUV C protein. Additionally, phylogenetic analysis revealed that duck DDX17 shares the highest homology (99.8%) with avian orthologs, and tissue distribution assays indicated its highest expression levels in the spleen and liver. This study is the first to reveal the replication-promoting role of DDX17 in avian DTMUV infection and further elucidates its molecular mechanism involving interaction with the viral C protein, providing a theoretical basis for antiviral strategies targeting host factors.