Glycoprotein-dependent acidification of vesicular stomatitis virus enhances release of matrix protein

Chad E. Mire, Derek Dube, Sue E. Delos, Judith M. White, Michael A. Whitt

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

To study vesicular stomatitis virus (VSV) entry and uncoating, we generated a recombinant VSV encoding a matrix (M) protein containing a C-terminal tetracysteine Lumio tag (rVSV-ML) that could be fluorescently labeled using biarsenical compounds. Quantitative confocal microscopy showed that there is a transient loss of fluorescence at early times after the initiation of endocytosis of rVSV-ML-Green (rVSV-MLG) virions, which did not occur when cells were treated with bafilomycin A1. The reduction in fluorescence occurred 5 to 10 min postentry, followed by a steady increase in fluorescence intensity from 15 to 60 min postentry. A similar loss of fluorescence was observed in vitro when virions were exposed to acidic pH. The reduction in fluorescence required G protein since "bald" ΔG-MLG particles did not show a similar loss of fluorescence at low pH. Based on the pH-dependent fluorescence properties of Lumio Green, we hypothesize that the loss of fluorescence of rVSV-MLG virions during virus entry is due to a G ectodomain-dependent acidification of the virion interior. Biochemical analysis indicated that low pH also resulted in an enhancement of M protein dissociation from partially permeabilized, but otherwise intact, wild-type virions. From these data we propose that low-pH conformational changes in G protein promote acidification of the virus interior, which facilitates the release of M from ribonucleoprotein particles during uncoating.

Original languageEnglish (US)
Pages (from-to)12139-12150
Number of pages12
JournalJournal of virology
Volume83
Issue number23
DOIs
StatePublished - Dec 2009

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology

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