An alphavirus temperature-sensitive capsid mutant reveals stages of nucleocapsid assembly

Yan Zheng, Margaret Kielian

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Alphaviruses have a nucleocapsid core composed of the RNA genome surrounded by an icosahedral lattice of capsid protein. An insertion after position 186 in the capsid protein produced a strongly temperature-sensitive growth phenotype. Even when the structural proteins were synthesized at the permissive temperature (28. °C), subsequent incubation of the cells at the non-permissive temperature (37. °C) dramatically decreased mutant capsid protein stability and particle assembly. Electron microscopy confirmed the presence of cytoplasmic nucleocapsids in mutant-infected cells cultured at the permissive temperature, but these nucleocapsids were not stable to sucrose gradient separation. In contrast, nucleocapsids isolated from mutant virus particles had similar stability to that of wildtype virus. Our data support a model in which cytoplasmic nucleocapsids go through a maturation step during packaging into virus particles. The insertion site lies in the interface between capsid proteins in the assembled nucleocapsid, suggesting the region where such a stabilizing transition occurs.

Original languageEnglish (US)
Pages (from-to)412-420
Number of pages9
JournalVirology
Volume484
DOIs
StatePublished - Oct 1 2015

Fingerprint

Alphavirus
Nucleocapsid
Capsid
Capsid Proteins
Temperature
Virion
Protein Stability
Product Packaging
Mutant Proteins
Sucrose
Cultured Cells
Electron Microscopy
Genome
RNA
Viruses
Phenotype
Growth

Keywords

  • Alphavirus
  • Nucleocapsid
  • Packaging
  • Temperature-sensitive mutant
  • Virus assembly
  • Virus budding

ASJC Scopus subject areas

  • Virology

Cite this

An alphavirus temperature-sensitive capsid mutant reveals stages of nucleocapsid assembly. / Zheng, Yan; Kielian, Margaret.

In: Virology, Vol. 484, 01.10.2015, p. 412-420.

Research output: Contribution to journalArticle

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