Cauliflower mosaic virus P6 inclusion body formation: A dynamic and intricate process

Virology. 2021 Jan 15:553:9-22. doi: 10.1016/j.virol.2020.10.003. Epub 2020 Oct 30.

Abstract

During an infection, Cauliflower mosaic virus (CaMV) forms inclusion bodies (IBs) mainly composed of viral protein P6, where viral activities occur. Because viral processes occur in IBs, understanding the mechanisms by which they are formed is crucial. FL-P6 expressed in N. benthamiana leaves formed IBs of a variety of shapes and sizes. Small IBs were dynamic, undergoing fusion/dissociation events. Co-expression of actin-binding polypeptides with FL-P6 altered IB size distribution and inhibited movement. This suggests that IB movement is required for fusion and growth. A P6 deletion mutant was discovered that formed a single large IB per cell, which suggests it exhibited altered fusion/dissociation dynamics. Myosin-inhibiting drugs did not affect small IB movement, while those inhibiting actin polymerization did. Large IBs colocalized with components of the aggresome pathway, while small ones generally did not. This suggests a possible involvement of the aggresome pathway in large IB formation.

Keywords: GFP-250; Latrunculin B; LifeAct; Liquid-liquid phase separation; Nonmembranous organelles; Pararetrovirus; Particle tracking.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Actin Cytoskeleton / metabolism
  • Caulimovirus / physiology*
  • Cell Membrane / metabolism
  • Coiled Bodies / metabolism
  • Diacetyl / analogs & derivatives
  • Diacetyl / pharmacology
  • Heterocyclic Compounds, 4 or More Rings / pharmacology
  • Inclusion Bodies, Viral / physiology*
  • Inclusion Bodies, Viral / ultrastructure
  • Microfilament Proteins / metabolism
  • Mutation
  • Nicotiana / virology
  • Plant Leaves / virology
  • Protein Domains
  • Trans-Activators / chemistry
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*

Substances

  • Heterocyclic Compounds, 4 or More Rings
  • Microfilament Proteins
  • Trans-Activators
  • gene VI protein, Cauliflower mosaic virus
  • diacetylmonoxime
  • blebbistatin
  • Diacetyl