Analysis of a fully infectious bio-orthogonally modified human virus reveals novel features of virus cell entry
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Author(s)
Type
Journal Article
Abstract
We report the analysis of a complex enveloped human virus, herpes simplex virus (HSV), assembled after in vivo incorporation of bio-orthogonal methionine analogues homopropargylglycine (HPG) or azidohomoalanine (AHA). We optimised protocols for the production of virions incorporating AHA (termed HSVAHA), identifying conditions which resulted in normal yields of HSV and normal particle/pfu ratios. Moreover we show that essentially every single HSVAHA capsid-containing particle was detectable at the individual particle level by chemical ligation of azide-linked fluorochromes to AHA-containing structural proteins. This was a completely specific chemical ligation, with no capsids assembled under normal methionine-containing conditions detected in parallel. We demonstrate by quantitative mass spectrometric analysis that HSVAHA virions exhibit no qualitative or quantitative differences in the repertoires of structural proteins compared to virions assembled under normal conditions. Individual proteins and AHA incorporation sites were identified in capsid, tegument and envelope compartments, including major essential structural proteins. Finally we reveal novel aspects of entry pathways using HSVAHA and chemical fluorochrome ligation that were not apparent from conventional immunofluorescence. Since ligation targets total AHA-containing protein and peptides, our results demonstrate the presence of abundant AHA-labelled products in cytoplasmic macrodomains and tubules which no longer contain intact particles detectable by immunofluorescence. Although these do not co-localise with lysosomal markers, we propose they may represent sites of proteolytic virion processing. Analysis of HSVAHA also enabled the discrimination from primary entering from secondary assembling virions, demonstrating assembly and second round infection within 6 hrs of initial infection and dual infections of primary and secondary virus in spatially restricted cytoplasmic areas of the same cell. Together with other demonstrated applications e.g., in genome biology, lipid and protein trafficking, this work further exemplifies the utility and potential of bio-orthogonal chemistry for studies in many aspects of virus-host interactions.
Date Issued
2019-10-07
Date Acceptance
2019-09-12
Citation
PLoS Pathogens, 2019, 15 (10)
ISSN
1553-7366
Publisher
Public Library of Science (PLoS)
Journal / Book Title
PLoS Pathogens
Volume
15
Issue
10
Copyright Statement
© 2019 Serwa et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Sponsor
Medical Research Council (MRC)
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/31589653
PII: PPATHOGENS-D-19-01158
Grant Number
MR/L000148/1
Subjects
Science & Technology
Life Sciences & Biomedicine
Microbiology
Parasitology
Virology
NEWLY SYNTHESIZED PROTEINS
AMINO-ACIDS
IDENTIFICATION
VISUALIZATION
HISTOGRAM
Amino Acids
Cell Proliferation
Cells, Cultured
Herpes Simplex
Herpesvirus 1, Human
Humans
Retinal Pigment Epithelium
Viral Structural Proteins
Virus Assembly
Virus Internalization
Cells, Cultured
Humans
Herpesvirus 1, Human
Herpes Simplex
Amino Acids
Viral Structural Proteins
Virus Assembly
Cell Proliferation
Virus Internalization
Retinal Pigment Epithelium
Virology
0605 Microbiology
1107 Immunology
1108 Medical Microbiology
Publication Status
Published
Coverage Spatial
United States
Article Number
ARTN e1007956