The vaccinia virus I3L gene product is localized to a complex endoplasmic reticulum-associated structure that contains the viral parental DNA. J Virol 2003 May;77(10):6014-28
Date
04/30/2003Pubmed ID
12719593Pubmed Central ID
PMC154049DOI
10.1128/jvi.77.10.6014-6028.2003Scopus ID
2-s2.0-0037694963 (requires institutional sign-in at Scopus site) 31 CitationsAbstract
The vaccinia virus (VV) I3L gene product is a single-stranded DNA-binding protein made early in infection that localizes to the cytoplasmic sites of viral DNA replication (S. C. Rochester and P. Traktman, J. Virol. 72:2917-2926, 1998). Surprisingly, when replication was blocked, the protein localized to distinct cytoplasmic spots (A. Domi and G. Beaud, J. Gen. Virol. 81:1231-1235, 2000). Here these I3L-positive spots were characterized in more detail. By using an anti-I3L peptide antibody we confirmed that the protein localized to the cytoplasmic sites of viral DNA replication by both immunofluorescence and electron microscopy (EM). Before replication had started or when replication was inhibited with hydroxyurea or cytosine arabinoside, I3L localized to distinct cytoplasmic punctate structures of homogeneous size. We show that these structures are not incoming cores or cytoplasmic sites of VV early mRNA accumulation. Instead, morphological and quantitative data indicate that they are specialized sites where the parental DNA accumulates after its release from incoming viral cores. By EM, these sites appeared as complex, electron-dense structures that were intimately associated with the cellular endoplasmic reticulum (ER). By double labeling of cryosections we show that they contain DNA and a viral early protein, the gene product of E8R. Since E8R is a membrane protein that is able to bind to DNA, the localization of this protein to the I3L puncta suggests that they are composed of membranes. The results are discussed in relation to our previous data showing that the process of viral DNA replication also occurs in close association with the ER.
Author List
Welsch S, Doglio L, Schleich S, Krijnse Locker JMESH terms used to index this publication - Major topics in bold
CytoplasmDNA, Viral
DNA-Binding Proteins
Endoplasmic Reticulum
Fluorescent Antibody Technique
HeLa Cells
Humans
Intracellular Membranes
Membrane Proteins
Microscopy, Electron
Vaccinia virus
Viral Proteins
Virus Replication
