ABSTRACT
Duck plague virus (DPV) belongs to the alphaherpesvirinae and causes high morbidity and mortality in waterfowl. UL47 is a large abundant structural protein in DPV, which means that UL47 protein plays an important role in virus replication. US3 protein, as a viral protein kinase in alphaherpesviruses, has been reported to be critical for DPV virion assembly. In this study, we over-expressed UL47 and US3 proteins and found that DPV UL47 protein was a phosphorylated substrate of US3 protein, which interacted and co-localized with US3 protein in the cytoplasm. US3-regulated phosphorylation of UL47 was important for the cytoplasmic localization of UL47 because non-phosphorylated UL47 was localized in the nucleus. The six sites of UL47 at Thr29, Ser30, Ser42, Thr47, Ser161, and Thr775 were identified as the phosphorylation targets of US3 protein. In vivo, UL47 phosphorylation was also detected but not in ΔUS3-infected cells. US3 protein promoted the cytoplasmic localization of UL47 at the late stage of infection, and the lack of US3 protein caused a delay in UL47 translocation to the cytoplasm. These results enhance our understanding of the functions of US3 during DPV infection and provide some references for DPV assembly.
ABSTRACT
To investigate the pivotal roles of the duck plague virus (DPV) tegument protein UL14 in viral replication, we generated 2 mutated viruses of DPV by using the bacterial artifcial chromosome system, the UL14-null mutant virus (CHv-BAC-ΔUL14) and the corresponding revertant virus (CHv-BAC-ΔUL14R). We found that the CHv-BAC-ΔUL14 viruses exhibited impaired virion morphogenesis in transmission electron microscopy (TEM) studies. Furthermore, CHv-BAC-ΔUL14 exhibited a plaque size reduction in duck embryo fibroblasts (DEFs). Finally, CHv-BAC-ΔUL14 exhibited a significant viral growth defect. Taken together, our findings suggest that DPV UL14 protein regulates viral morphogenesis for efficient viral replication.
