Aggregation of TMV CP plays a role in CP functions and in coat-protein-mediated resistance

S. Asurmendi, R. H. Berg, T. J. Smith, M. Bendahmane, R. N. Beachy

Research output: Contribution to journalArticlepeer-review

48 Scopus citations

Abstract

Tobacco mosaic virus (TMV) coat protein (CP) in absence of RNA self-assembles into several different structures depending on pH and ionic strength. Transgenic plants that produce self-assembling CP are resistant to TMV infection, a phenomenon referred to as coat-protein-mediated resistance (CP-MR). The mutant CP Thr42Trp (CPT42W) produces enhanced CP-MR compared to wild-type CP. To establish the relationship between the formation of 20S CP aggregates and CP-MR, virus-like particles (VLPs) produced by TMV variants that yield high levels of CP-MR were characterized. We demonstrate that non-helical structures are found in VLPs formed in vivo by CPT42W but not by wild-type CP and suggest that the mutation shifts the intracellular equilibrium of aggregates from low to higher proportions of non-helical 20S aggregates. A similar shift in equilibrium of aggregates was observed with CPD77R, another mutant that confers high level of CP-MR. The mutant CPD50R confers a level of CP-MR similar to wild-type CP and aggregates in a manner similar to wild-type CP. We conclude that increased CP-MR is correlated with a shift in intracellular equilibrium of CP aggregates, including aggregates that interfere with virus replication.

Original languageEnglish (US)
Pages (from-to)98-106
Number of pages9
JournalVirology
Volume366
Issue number1
DOIs
StatePublished - Sep 15 2007
Externally publishedYes

Keywords

  • 20S
  • CP aggregates
  • CP mutants
  • CP-MR mechanism
  • Stacked disk
  • TMV

ASJC Scopus subject areas

  • Virology

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