Genetic and cell biological characterization of the vaccinia virus A30 and G7 phosphoproteins. J Virol 2005 Jun;79(11):7146-61
Date
05/14/2005Pubmed ID
15890954Pubmed Central ID
PMC1112092DOI
10.1128/JVI.79.11.7146-7161.2005Scopus ID
2-s2.0-18744395205 (requires institutional sign-in at Scopus site) 37 CitationsAbstract
The vaccinia virus proteins A30 and G7 are known to play essential roles in early morphogenesis, acting prior to the formation of immature virions. Their repression or inactivation results in the accumulation of large virosomes, detached membrane crescents, and empty immature virions. We have undertaken further study of these proteins to place them within the context of the F10 kinase, the A14 membrane protein, and the H5 phosphoprotein, which have been the focus of previous studies within our laboratory. Here we confirm that both A30 and G7 undergo F10 kinase-dependent phosphorylation in vivo and recapitulate that modification of A30 in vitro. Although the detached crescents observed upon loss of A30 or G7 echo those seen upon repression of A14, no interaction between A30/G7 and A14 could be detected. We did, however, determine that the A30 and G7 proteins are unstable during nonpermissive tsH5 infections, suggesting that the loss of A30/G7 is the underlying cause for the formation of lacy or curdled virosomes. We also determined that the temperature-sensitive phenotype of the Cts11 virus is due to mutations in two codons of the G7L gene. Phenotypic analysis of nonpermissive Cts11 infections indicated that these amino acid substitutions compromise G7 function without impairing the stability of either G7 or A30. Utilizing Cts11 in conjunction with a rifampin release assay, we determined that G7 acts at multiple stages of virion morphogenesis that can be distinguished both by ultrastructural analysis and by monitoring the phosphorylation status of several viral proteins that undergo F10-mediated phosphorylation.
Author List
Mercer J, Traktman PMESH terms used to index this publication - Major topics in bold
Amino Acid SequenceAmino Acid Substitution
Animals
Base Sequence
Cell Line
DNA, Viral
Genes, Viral
Microscopy, Electron
Models, Biological
Molecular Sequence Data
Mutation
Phenotype
Phosphoproteins
Phosphorylation
Protein Processing, Post-Translational
Sequence Homology, Amino Acid
Substrate Specificity
Temperature
Vaccinia virus
Viral Proteins
Virus Assembly
