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Vaccinia virus DNA replication occurs in endoplasmic reticulum-enclosed cytoplasmic mini-nuclei (2001)
| Venue: | Mol. Biol. Cell |
| Citations: | 16 - 0 self |
BibTeX
@ARTICLE{Tolonen01vacciniavirus,
author = {Nina Tolonen and Laura Doglio and Sibylle Schleich and Jacomine Krijnse Locker and Suzanne R. Pfeffer},
title = {Vaccinia virus DNA replication occurs in endoplasmic reticulum-enclosed cytoplasmic mini-nuclei},
journal = {Mol. Biol. Cell},
year = {2001},
pages = {12--2031}
}
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Abstract
Vaccinia virus (vv), a member of the poxvirus family, is unique among most DNA viruses in that its replication occurs in the cytoplasm of the infected host cell. Although this viral process is known to occur in distinct cytoplasmic sites, little is known about its organization and in particular its relation with cellular membranes. The present study shows by electron microscopy (EM) that soon after initial vv DNA synthesis at 2 h postinfection, the sites become entirely surrounded by membranes of the endoplasmic reticulum (ER). Complete wrapping requires �45 min and persists until virion assembly is initiated at 6 h postinfection, and the ER dissociates from the replication sites. [ 3 H]Thymidine incorporation at different infection times shows that efficient vv DNA synthesis coincides with complete ER wrapping, suggesting that the ER facilitates viral replication. Proteins known to be associated with the nuclear envelope in interphase cells are not targeted to these DNA-surrounding ER membranes, ruling out a role for these molecules in the wrapping process. By random green fluorescent protein-tagging of vv early genes of unknown function with a putative transmembrane domain, a novel vv protein, the gene product of E8R, was identified that is targeted to the ER around the DNA sites. Antibodies raised against this vv early membrane protein showed, by immunofluorescence microscopy, a characteristic ring-like pattern around the replication site. By electron microscopy quantitation the protein concentrated in the ER surrounding the DNA site and was preferentially targeted to membrane facing the inside of this site. These combined data are discussed in relation to nuclear envelope assembly/disassembly as it occurs during the cell cycle.
Keyphrases
endoplasmic reticulum-enclosed cytoplasmic mini-nuclei vaccinia virus dna replication nuclear envelope novel vv protein complete er wrapping vaccinia virus wrapping process random green fluorescent protein-tagging efficient vv dna synthesis coincides cell cycle electron microscopy quantitation vv early membrane protein virion assembly putative transmembrane domain viral replication vv early gene immunofluorescence microscopy thymidine incorporation poxvirus family gene product dna-surrounding er membrane present study show cellular membrane infected host cell endoplasmic reticulum dna virus distinct cytoplasmic site electron microscopy initial vv dna synthesis interphase cell viral process different infection time characteristic ring-like pattern dna site complete wrapping replication site unknown function
