Vaccinia virus F12L protein is required for actin tail formation, normal plaque size, and virulence.
Vaccinia virus gene F12L is shown to encode a 65-kDa protein that is synthesized early and late during infection and that is not modified by glycosylation. Computational sequence comparison revealed that related proteins are encoded by all sequenced chordopoxviruses. A virus deletion mutant lacking the F12L gene (vDeltaF12L) and a revertant virus with the F12L gene reinserted into the deletion mutant (vF12L-rev) were constructed and analyzed. A version of the F12L gene with a C-terminal amino acid tag derived from the influenza virus hemagglutinin and that is recognized by a monoclonal antibody was also inserted into the F12L locus of vDeltaF12L. Loss of the F12L protein reduced the formation of IMV 2-fold, but there was a dramatic (99.5%) reduction in actin tail formation, and the levels of cell-associated enveloped virus and extracellular enveloped virus were reduced 8- to 11-fold and 7-fold, respectively. Consistent with the lack of actin tail formation, vDeltaF12L produced a very small plaque. The vDeltaF12L virus was severely attenuated in vivo, such that a dose of vDeltaF12L 10,000-fold greater than the dose of wild-type virus that induced severe disease was unable to induce disease in mice infected intranasally.
Zhang
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WH
Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom.
Wilcock
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D
Smith
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GL
D000199:Actins / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D015967:Gene Expression Regulation, Viral; D005814:Genes, Viral; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D014615:Vaccinia / Q000378:metabolism / Q000821:virology*; D014616:Vaccinia virus / Q000235:genetics* / Q000472:pathogenicity; D014764:Viral Proteins / Q000235:genetics*; D014774:Virulence / Q000235:genetics
D000199:Actins; C417882:F12L protein, Vaccinia virus; D014764:Viral Proteins