Imaging the alphavirus exit pathway

Maria Guadalupe Martinez, Erik Lee Snapp, Geoffrey S. Perumal, Frank P. Macaluso, Margaret Kielian

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Alphaviruses are small enveloped RNA viruses with highly organized structures that exclude host cell proteins. They contain an internal nucleocapsid and an external lattice of the viral E2 and E1 transmembrane proteins. Alphaviruses bud from the plasma membrane (PM), but the process and dynamics of alphavirus assembly and budding are poorly understood. Here we generated Sindbis viruses (SINVs) with fluorescent protein labels on the E2 envelope protein and exploited them to characterize virus assembly and budding in living cells. During virus infection, E2 became enriched in localized patches on the PM and in filopodium-like extensions. These E2-labeled patches and extensions contained all of the viral structural proteins. Correlative light and electron microscopy studies established that the patches and extensions colocalized with virus budding structures, while light microscopy showed that they excluded a freely diffusing PM marker protein. Exclusion required the interaction of the E2 protein with the capsid protein, a critical step in virus budding, and was associated with the immobilization of the envelope proteins on the cell surface. Virus infection induced two distinct types of extensions: tubulin-negative extensions that wereμ2 to 4 μm in length and excluded the PM marker, and tubulin-positive extensions that were>10 μmlong, contained the PM marker, and could transfer virus particles to noninfected cells. Tubulin-positive extensions were selectively reduced in cells infected with a nonbudding SINV mutant. Together, our data support a model in which alphavirus infection induces reorganization of the PM and cytoskeleton, leading to virus budding from specialized sites.

Original languageEnglish (US)
Pages (from-to)6922-6933
Number of pages12
JournalJournal of Virology
Volume88
Issue number12
DOIs
StatePublished - 2014

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Alphavirus
Virus Release
plasma membrane
Cell Membrane
image analysis
Tubulin
tubulin
Sindbis virus
Sindbis Virus
viruses
Virus Diseases
Proteins
proteins
Alphavirus Infections
cells
light microscopy
Membrane Proteins
viral morphology
infection
pseudopodia

ASJC Scopus subject areas

  • Immunology
  • Virology

Cite this

Imaging the alphavirus exit pathway. / Martinez, Maria Guadalupe; Snapp, Erik Lee; Perumal, Geoffrey S.; Macaluso, Frank P.; Kielian, Margaret.

In: Journal of Virology, Vol. 88, No. 12, 2014, p. 6922-6933.

Research output: Contribution to journalArticle

Martinez, MG, Snapp, EL, Perumal, GS, Macaluso, FP & Kielian, M 2014, 'Imaging the alphavirus exit pathway', Journal of Virology, vol. 88, no. 12, pp. 6922-6933. https://doi.org/10.1128/JVI.00592-14
Martinez, Maria Guadalupe ; Snapp, Erik Lee ; Perumal, Geoffrey S. ; Macaluso, Frank P. ; Kielian, Margaret. / Imaging the alphavirus exit pathway. In: Journal of Virology. 2014 ; Vol. 88, No. 12. pp. 6922-6933.
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