PQBP1 Regulates the Cellular Inflammation Induced by Avian Reovirus and Interacts with the Viral P17 Protein

Avian reovirus (ARV) can commonly infect a flock and cause immunosuppressive diseases in poultry. The nonstructural protein p17 is involved in viral replication, and significant progress has been made in showing its ability to regulate cellular signaling pathways. In our previous study, to further investigate the effect of ARV p17 protein on viral replication, the host protein polyglu-tamine binding protein 1 (PQBP1) was identified to interact with p17 by a yeast two-hybrid system. In the current study, the interaction between PQBP1 and p17 protein was further confirmed by laser confocal microscopy and coimmunoprecipitation assays. In addition, the N-terminal WWD of PQBP1 was found to mediate the process of binding to the p17 protein. Interestingly, we found that ARV infection significantly inhibited PQBP1 expression. While the quantity of ARV replication was largely influenced by PQBP1, PQBP1 overexpression decreased ARV replication. In contrast, upon PQBP1 knockdown, the quantity of ARV was notably increased. ARV infection and p17 protein expression were both proven to induce PQBP1 to mediate cellular inflammation. In the current study, we revealed through qRT‒PCR, ELISA and Western blotting methods that PQBP1 plays a positive role in ARV-induced inflammation. Furthermore, the mechanism of this process was shown to involve the NFκB-dependent transcription of inflammatory genes. In addition, PQBP1 was shown to regulate the phosphorylation of p65 protein. In conclusion, this research provides clues to elucidating the function of the p17 protein and the pathogenic mechanism of ARV, especially the cause of the inflammatory response. It also provides new ideas for the study of therapeutic targets of ARV.