Abstract
BackgroundPseudorabies virus (PRV) protein UL56 (pUL56) has been implicated in viral dissemination and virulence in vivo. However, the properties of PRV pUL56 remain largely unknown. In the present study, we aim to investigate the subcellular localization of pUL56 and the underlying molecular basis in transfected cells.MethodsConstructs of N-terminal green fluorescent protein (GFP) fused pUL56 and its truncations were employed for investigating subcellular localization and further identifying amino acids crucial for pUL56 localization in transfected Vero cells. Finally, the identified amino acids were replaced with alanine for confirming if these mutations could impair the specific localization of pUL56.ResultsThe pUL56 predominantly localized at the Golgi and trans-Golgi network (TGN) through its predicted C-terminal transmembrane helix in transfected Vero cells. A Golgi-associated protein Rab6a, independent of interaction with pUL56, was significantly downregulated by pUL56. Further, we found three truncated pUL56 C-terminal fragments (174–184, 175–185 and 191–195) could restrict GFP in the perinuclear region, respectively. Within these truncations, the 174proline (P), 181leucine (L), 185L and 191L were essential for maintaining perinuclear accumulation, thus suggesting an important role of leucine. Alanine (A) mutagenesis assays were employed to generate a series of pUL56 C-terminal mutants on the basis of leucine. Finally, a pUL56 mutant M10 (174P/A-177L/A-181L/A-185L/A-191L/A-194L/A-195I/A-196-197L/A-200L/A) lost Golgi-TGN localization. Thus, our data revealed that the leucine-rich transmembrane helix was responsible for pUL56 Golgi-TGN localization and retention, probably through specific intracellular membrane insertion.ConclusionOur data indicated that the C-terminal transmembrane helix was responsible for the Golgi-TGN localization of pUL56. In addition, the leucines within C-terminal transmembrane helix were essential for maintaining pUL56 Golgi-TGN retention in cells. Further, the pUL56 can induce downregulation of Golgi-associated protein Rab6a.
Highlights
Pseudorabies virus (PRV) protein UL56 has been implicated in viral dissemination and virulence in vivo
We identified that the Golgi and trans-Golgi network (TGN) were the main sites of PRV protein UL56 (pUL56) targeting in transfected Vero cells
In order to compare difference between genotype I and II PRV pUL56, the amino acid sequences collected from five strains were used for further analyses
Summary
Pseudorabies virus (PRV) protein UL56 (pUL56) has been implicated in viral dissemination and virulence in vivo. Pseudorabies virus (PRV), a causative agent of pseudorabies (PR) or Aujezsky’s disease, belongs to the Herpesviridae family, Alphaherpeviridae subfamily [1]. The viral genome is wrapped in an icosahedral capsid surrounded by a proteinaceous tegument layer and a lipid envelope [5]. Tegument proteins in alphaherpesviruses link the viral capsid to the envelope and contribute to multiple biological functions [5]. These proteins can be classified as “inner” or “outer” tegument proteins, on the basis of their association with either the capsid or viral envelope during entry and egress [6, 7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
