The Pivotal Roles of US3 Protein in Cell-to-Cell Spread and Virion Nuclear Egress of Duck Plague Virus

Liyao Deng,Sai Mao,Mingshu Wang,Ling Zhang,Xinxin Zhao,Bin Tian,Xumin Ou,Mafeng Liu,Renyong Jia,Leichang Pan,Dekang Zhu,Mujeeb Ur Rehman,Anchun Cheng,Shun Chen,Qiao Yang,Yanling Yu,Ying Wu,Juan Huang,Yunya Liu,Shaqiu Zhang,Xiaoyue Chen

doi:10.1038/s41598-020-64190-2

Abstract

The duck plague virus (DPV) US3 protein, a homolog of the herpes simplex virus-1 (HSV-1) US3 protein that is reported to be critical for viral replication, has been minimally studied. Therefore, to investigate the function of the DPV US3 protein, we used scarless Red recombination technology based on an infectious bacterial artificial chromosome (BAC) containing the DPV Chinese virulent strain (CHv) genome and successfully constructed and rescued a US3-deleted mutant and the corresponding revertant virus (BAC-CHv-ΔUS3 and BAC-CHv-ΔUS3R, respectively). For viral growth characteristics, compared to the parental and revertant viruses, the US3-deleted mutant showed an approximately 100-fold reduction in viral titers but no significant reduction in genome copies, indicating that the US3-deleted mutant exhibited decreased viral replication but not decreased viral DNA generation. In addition, the US3-deleted mutant formed viral plaques that were 33% smaller on average than those formed by the parental and revertant viruses, demonstrating that US3 protein affected the viral cell-to-cell spread of DPV. Finally, the results of electron microscopy showed that the deletion of US3 resulted in a large number of virions accumulating in the nucleus and perinuclear space, thus blocking virion nuclear egress. In this study, we found that the DPV US3 protein played pivotal roles in viral replication by promoting viral cell-to-cell spread and virion nuclear egress, which may provide some references for research on the function of the DPV US3 protein.

Highlights

Duck plague, known as duck viral enteritis (DVE), is an acute, febrile, septic disease that appears in waterfowl and is caused by duck plague virus (DPV)
Only a few proteins encoded by DPV apart from UL54 and UL13 have been studied in mutant viruses
Alpha-herpesvirus US3 protein has been reported to be a serine/threonine kinase that phosphorylates a variety of proteins, including the viral proteins UL31, UL34, UL47 and gB20–22, and the host proteins Lamin A/C, p65, IRF3, group A p21-activated kinases (PAKs) and Bad[23,24,25,26,27], a proapoptotic protein

Summary

Introduction

Known as duck viral enteritis (DVE), is an acute, febrile, septic disease that appears in waterfowl and is caused by duck plague virus (DPV). The effect of the herpes simplex virus-1 (HSV-1) US3 protein on virion nuclear egress is related to kinase activity Both US3 deletion and US3 kinase-dead mutations of HSV-1 caused virion accumulation in the perinuclear space, which was regulated by the phosphorylation of UL31, UL34, UL47, gB and Lamin A/C through US3 protein[28,29,30,31]. Electron microscopy analysis indicated that the US3-deleted mutant displayed accumulation of a large number of virions in the nucleus and perinuclear space, preventing nucleocapsids from undergoing further assembly and maturation These data are the first to show that the DPV US3 protein affects viral replication by regulating viral cell-to-cell spread and virion nuclear egress, which will provide some references for research on the function of US3 protein and the prevention and control of DPV

Methods

Results

Conclusion