The vaccinia virus gene I2L encodes a membrane protein with an essential role in virion entry. J Virol 2008 Oct;82(20):10247-61
Date
08/15/2008Pubmed ID
18701587Pubmed Central ID
PMC2566298DOI
10.1128/JVI.01035-08Scopus ID
2-s2.0-53749100880 (requires institutional sign-in at Scopus site) 44 CitationsAbstract
The previously unstudied vaccinia virus gene I2L is conserved in all orthopoxviruses. We show here that the 8-kDa I2 protein is expressed at late times of infection, is tightly associated with membranes, and is encapsidated in mature virions. We have generated a recombinant virus in which I2 expression is dependent upon the inclusion of tetracycline in the culture medium. In the absence of I2, the biochemical events of the viral life cycle progress normally, and virion morphogenesis culminates in the production of mature virions. However, these virions show an approximately 400-fold reduction in specific infectivity due to an inability to enter target cells. Several proteins that have been previously identified as components of an essential entry/fusion complex are present at reduced levels in I2-deficient virions, although other membrane proteins, core proteins, and DNA are encapsidated at normal levels. A preliminary structure/function analysis of I2 has been performed using a transient complementation assay: the C-terminal hydrophobic domain is essential for protein stability, and several regions within the N-terminal hydrophilic domain are essential for biological competency. I2 is thus yet another component of the poxvirus virion that is essential for the complex process of entry into target cells.
Author List
Nichols RJ, Stanitsa E, Unger B, Traktman PMESH terms used to index this publication - Major topics in bold
Amino Acid SequenceAnimals
Cell Line
DNA Replication
Gene Expression Regulation, Viral
Genetic Complementation Test
Humans
Membrane Proteins
Molecular Sequence Data
Sequence Alignment
Sequence Homology, Amino Acid
Vaccinia virus
Viral Proteins
Virion
Virus Internalization
