The vaccinia virus I1 protein is essential for the assembly of mature virions. J Virol 1997 Dec;71(12):9285-94
Date
11/26/1997Pubmed ID
9371587Pubmed Central ID
PMC230231DOI
10.1128/JVI.71.12.9285-9294.1997Scopus ID
2-s2.0-0030856298 (requires institutional sign-in at Scopus site) 37 CitationsAbstract
The product of the vaccinia virus I1 gene was characterized biochemically and genetically. This 35-kDa protein is conserved in diverse members of the poxvirus family but shows no homology to nonviral proteins. We show that recombinant I1 binds to both single-stranded and double-stranded DNA in a sequence-nonspecific manner in an electrophoretic mobility shift assay. The protein is expressed at late times during infection, and approximately 700 copies are encapsidated within the virion core. To determine the role of the I1 protein during the viral life cycle, a inducible viral recombinant in which the I1 gene was placed under the regulation of the Escherichia coli lac operator/repressor was constructed. In the absence of isopropyl-beta-D-thiogalactopyranoside, plaque formation was abolished and yields of infectious, intracellular virus were dramatically reduced. Although all phases of gene expression and DNA replication proceeded normally during nonpermissive infections, no mature virions were produced. Electron microscopic analysis confirmed the absence of mature virion assembly but revealed that apparently normal immature virions accumulated. Thus, I1 is an encapsidated DNA-binding protein required for the latest stages of vaccinia virion morphogenesis.
Author List
Klemperer N, Ward J, Evans E, Traktman PMESH terms used to index this publication - Major topics in bold
Amino Acid SequenceAnimals
Antibodies, Viral
Base Sequence
Cell Line
DNA
DNA, Viral
DNA-Binding Proteins
Endopeptidases
Gene Expression Regulation, Viral
Mice
Molecular Sequence Data
Phenotype
Protein Processing, Post-Translational
Recombinant Fusion Proteins
Vaccinia virus
Viral Core Proteins
Viral Proteins
Virion
Virus Assembly
