Electron microscopy of in-plaque phage T3 assembly: Proposed analogs of neurodegenerative disease triggers

Philip Serwer, Barbara Hunter, Elena T. Wright

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Increased knowledge of virus assembly-generated particles is needed for understanding both virus assembly and host responses to virus infection. Here, we use a phage T3 model and perform electron microscopy (EM) of thin sections (EM-TS) of gel-supported T3 plaques formed at 30 C. After uranyl acetate/lead staining, we observe intracellular black particles, some with a difficult-to-see capsid. Some black particles (called LBPs) are larger than phage particles. The LBP frequency is increased by including proflavine, a DNA packaging inhibitor, in the growth medium and increasing plaque-forming temperature to 37 C. Acidic phosphotungstate-precipitate (A-PTA) staining causes LBP substitution by black rings (BRs) that have the size and shape expected of hyper-expanded capsid containers for LBP DNA. BRs are less frequent in liquid cultures, suggesting that hyper-expanded capsids evolved primarily for in-gel (e.g., in-biofilm) propagation. BR-specific A-PTA staining and other observations are explained by α-sheet intense structure of the major subunit of hyper-expanded capsids. We hypothesize that herpes virus triggering of neurodegenerative disease occurs via in-gel propagation-promoted (1) generation of α-sheet intense viral capsids and, in response, (2) host production of α-sheet intense, capsid-interactive, innate immunity amyloid protein that becomes toxic. We propose developing viruses that are therapeutic via detoxifying interaction with this innate immunity protein.

Original languageEnglish (US)
Article number18
JournalPharmaceuticals
Volume13
Issue number1
DOIs
StatePublished - Jan 2020

Keywords

  • Assembly-generated particles
  • Obscure
  • Phage capsids
  • Protein staining
  • Protein structure
  • Thin sections

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmaceutical Science

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