Linked Life Data

9454708

Source:http://linkedlifedata.com/resource/pubmed/id/9454708

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1998-2-20
pubmed:abstractText
A plasmid-based recovery system was used to generate four unique vesicular stomatitis virus (VSV) mutants that encode glycoproteins (G proteins) with single or double amino acid substitutions in two conserved acidic residues adjacent to the putative G protein fusion domain. Previously we demonstrated that three of the mutant G proteins (D137-L, E139-L, and DE-SS) have slightly reduced pH thresholds for membrane fusion activity. In this report we show that even though the viruses encoding D137-L, E139-L, and DE-SS were recovered with high efficiency, these mutants were attenuated for growth in cell culture. Plaque formation was significantly delayed with these mutants and the plaques were smaller and more diffuse than those produced by wild type VSV. In addition, cells infected with these mutants produced approximately 5- to 10-fold less infectious virus than cells infected with a similarly recovered VSV encoding the wild-type G protein. Using R18-labeled virus we found that the mutant G proteins had approximately 50% of the fusion activity of wild-type G at pH 6.3 and only 75% activity at pH 5.8. We also show that the mutant viruses were more sensitive to chloroquine inhibition of infection than either wild-type VSV or the mutant E139-T, which has a fusion phenotype similar to wild-type G protein. Reduced fusion activity and attenuation of infectivity was not due to differences in the amount of G protein incorporated into virions, nor to differences in the amount of virus binding to cells at physiological pH. Although infectivity was assayed at neutral pH, we observed an increase in virus binding with both mutant and wild-type virions as the pH was lowered, and the increase in binding occurred near the pH threshold for membrane fusion activity. From these data we propose a model in which VSV entry involves an increase in virus binding to the inner leaflet of the endosomal membrane during endosome acidification. Concomitant with this higher affinity binding, G protein becomes primed to initiate fusion of the viral envelope with the endosomal membrane. Viruses with mutations that delay the onset of increased binding and fusion lag behind wild-type VSV in their ability to initiate a productive infection, potentially because the location within the cytoplasm where these viruses ultimately fuse is not optimal for either virus uncoating or replication of the viral genome.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0042-6822
pubmed:author
pubmed:issnType
Print
pubmed:day
20
pubmed:volume
240
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
349-58
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Attenuation of recombinant vesicular stomatitis viruses encoding mutant glycoproteins demonstrate a critical role for maintaining a high pH threshold for membrane fusion in viral fitness.
pubmed:affiliation
Department of Microbiology and Immunology, University of Tennessee-Memphis 38163, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't