Fluorescent tagging of herpes simplex virus tegument protein VP13/14 in virus infection

J Virol. 2001 Mar;75(6):2575-83. doi: 10.1128/JVI.75.6.2575-2583.2001.

Abstract

The cellular site of herpesvirus tegument assembly has yet to be defined. We have previously used a recombinant herpes simplex virus type 1 expressing a green fluorescent protein (GFP)-tagged tegument protein, namely VP22, to show that VP22 is localized exclusively to the cytoplasm during infection. Here we have constructed a similar virus expressing another fluorescent tegument protein, YFP-VP13/14, and have visualized the intracellular localization of this second tegument protein in live infected cells. In contrast to VP22, VP13/14 is targeted predominantly to the nuclei of infected cells at both early and late times in infection. More specifically, YFP-13/14 localizes initially to the nuclear replication compartments and then progresses into intense punctate domains that appear at around 12 h postinfection. At even later times this intranuclear punctate fluorescence is gradually replaced by perinuclear micropunctate and membranous fluorescence. While the vast majority of YFP-13/14 seems to be targeted to the nucleus, a minor subpopulation also appears in a vesicular pattern in the cytoplasm that closely resembles the pattern previously observed for GFP-22. Moreover, at late times weak fluorescence appears at the cell periphery and in extracellular virus particles, confirming that YFP-13/14 is assembled into virions. This predominantly nuclear targeting of YFP-13/14 together with the cytoplasmic targeting of VP22 may imply that there are multiple sites of tegument protein incorporation along the virus maturation pathway. Thus, our YFP-13/14-expressing virus has revealed the complexity of the intracellular targeting of VP13/14 and provides a novel insight into the mechanism of tegument, and hence virus, assembly.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • COS Cells
  • Cell Nucleus / metabolism*
  • Chlorocebus aethiops
  • Green Fluorescent Proteins
  • Herpesvirus 1, Human / physiology*
  • Image Processing, Computer-Assisted
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism*
  • Microscopy, Confocal
  • Recombinant Fusion Proteins / metabolism
  • Vero Cells
  • Viral Fusion Proteins / genetics
  • Viral Fusion Proteins / metabolism*
  • Virion / metabolism
  • Virus Assembly
  • Virus Replication*

Substances

  • Luminescent Proteins
  • Recombinant Fusion Proteins
  • VP13-14 protein, herpes simplex virus type 1
  • Viral Fusion Proteins
  • Green Fluorescent Proteins