Identification and subcellular localization of proteins that interact with Duck plague virus pUL14 in infected host cells.

Duck plague (DP), which is caused by duck plague virus (DPV), is an infectious disease that severely harms the waterfowl breeding industry. The UL14 protein (pUL14) is a tegument protein encoded by the UL14 gene, which is located in the unique long (UL) region of the DPV genome. DPV pUL14 plays a crucial role in viral replication, likely by interacting with host and viral proteins that have yet to be identified. In this study, glutathione-S-transferase (GST) pull-down combined with liquid chromatography-mass spectrometry (LC-MS/MS) was employed to identify pUL14-interacting proteins in DPV-infected cells. A total of 281 host proteins and 58 viral proteins that interacted with pUL14 were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses revealed that the identified proteins could be assigned to several different subcellular locations and functional classes. These proteins are associated mainly with the regulation of biological processes, RNA biosynthetic processes, and nuclear export. In addition, four viral proteins of interest, the α-gene transducing factor (α-TIF) pUL48, the nuclear egress complex (NEC) proteins pUL31/34, and pUL51, a protein involved in secondary envelopment, were validated by coimmunoprecipitation (co-IP) to interact with DPV pUL14. Additionally, the nuclear export signal (NES) was identified in a leucine-rich region at aa 77-87 (77VQTKIEEQLAI87) of DPV pUL14. The interactome data between DPV pUL14 and host/viral proteins contribute to understanding the role of DPV pUL14 in the replication of DPV.