Fluorescent protein tagging of adenoviral proteins pV and pIX reveals 'late virion accumulation compartment'

PLoS Pathog. 2020 Jun 25;16(6):e1008588. doi: 10.1371/journal.ppat.1008588. eCollection 2020 Jun.

Abstract

The human adenovirus type 5 (HAdV5) causes disease of the upper and lower respiratory tract. The early steps of HAdV5 entry up to genome replication in the host nucleus have been extensively studied. However, late stages of infection remain poorly understood. Here, we set out to elucidate the spatiotemporal orchestration of late adenovirus nuclear remodeling in living cells. We generated virus mutants expressing fluorescently tagged protein IX (pIX) and protein V (pV), a capsid and viral genome associated protein, respectively. We found that during progeny virion production both proteins localize to a membrane-less, nuclear compartment, which is highly impermeable such that in immunofluorescence microscopy antibodies can hardly penetrate it. We termed this compartment 'late virion accumulation compartment' (LVAC). Correlation between light- and electron microscopy revealed that the LVAC contains paracrystalline arrays of viral capsids that arrange tightly packed within a honeycomb-like organization of viral DNA. Live-cell microscopy as well as FRAP measurements showed that the LVAC is rigid and restricts diffusion of larger molecules, indicating that capsids are trapped inside.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • A549 Cells
  • Adenovirus Infections, Human / genetics
  • Adenovirus Infections, Human / metabolism*
  • Adenovirus Infections, Human / pathology
  • Adenoviruses, Human / physiology*
  • Capsid Proteins / genetics
  • Capsid Proteins / metabolism*
  • Capsid Proteins / ultrastructure
  • DNA, Viral / genetics
  • DNA, Viral / metabolism*
  • Humans
  • Virion / genetics
  • Virion / metabolism*
  • Virus Replication*

Substances

  • Capsid Proteins
  • DNA, Viral

Grants and funding

SP was supported by the Strategic Incentive Programme of the Heinrich Pette Institute and part of Leibniz ScienceCampus InterACt (Grant Agreement No. W6/2018). The Heinrich Pette Institute, Leibniz Institute for Experimental Virology is supported by the Free and Hanseatic City of Hamburg and the Federal Ministry of Health. LEF was supported by the European Molecular Biology Organization, long-term fellowship (ALTF 356-2018), www.embo.org. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.