Low-Fidelity Assembly of Influenza A Virus Promotes Escape from Host Cells

Vahey, Michael D.; Fletcher, Daniel A.

doi:10.1016/j.cell.2018.10.056

Cited by 70 publications

(78 citation statements)

References 78 publications

(90 reference statements)

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“…In light of the tegument's primary role in manipulating host cells to facilitate virus replication, the multiple layers of structural variability at play in the tegument provide unique opportunities in the context of herpesvirus adaptability. In much the same way that more genetically fluid RNA viruses such as influenza viruses (Harris et al, 2006;Vahey and Fletcher, 2019), filoviruses (Bharat et al, 2011), and coronaviruses (Goldsmith et al, 2004) benefit from heterogeneous compositions to rapidly respond to selective pressures, structural pleomorphism may provide a crucial avenue of diversity in more genetically constrained dsDNA viruses (because of lower mutation rates) like KSHV, resulting in an increase in evolutionary bandwidth. In essence, facing a relative lack of intraspecies genetic diversity (the tradeoff is more viable progeny), adaptability regarding the ability to manipulate hosts is, instead, implemented at a structural level.…”

Section: Catc Binding Implications For Capsid Assembly and Diversitymentioning

confidence: 99%

DNA-Packing Portal and Capsid-Associated Tegument Complexes in the Tumor Herpesvirus KSHV

Gong

Dai

Jih

et al. 2019

Cell

110

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Graphical Abstract Highlights d Genome-packing portal and capsid-associated tegument complexes (CATCs) resolved d Partial and asymmetric CATC occupancy introduces structural variability d CATC binding introduces 120 counterclockwise rotation of triplex Ta on the capsid d Structure-based mutageneses reveal binding hotspot for antiviral development SUMMARYAssembly of Kaposi's sarcoma-associated herpesvirus (KSHV) begins at a bacteriophage-like portal complex that nucleates formation of an icosahedral capsid with capsid-associated tegument complexes (CATCs) and facilitates translocation of an $150-kb dsDNA genome, followed by acquisition of a pleomorphic tegument and envelope. Because of deviation from icosahedral symmetry, KSHV portal and tegument structures have largely been obscured in previous studies. Using symmetry-relaxed cryo-EM, we determined the in situ structure of the KSHV portal and its interactions with surrounding capsid proteins, CATCs, and the terminal end of KSHV's dsDNA genome. Our atomic models of the portal and capsid/CATC, together with visualization of CATCs' variable occupancy and alternate orientation of CATC-interacting vertex triplexes, suggest a mechanism whereby the portal orchestrates procapsid formation and asymmetric long-range determination of CATC attachment during DNA packaging prior to pleomorphic tegumentation/envelopment. Structure-based mutageneses confirm that a triplex deep binding groove for CATCs is a hotspot that holds promise for antiviral development.

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Section: Catc Binding Implications For Capsid Assembly and Diversitymentioning

confidence: 99%

DNA-Packing Portal and Capsid-Associated Tegument Complexes in the Tumor Herpesvirus KSHV

Gong

Dai

Jih

et al. 2019

Cell

110

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“…For example, the cell-to-cell variable viral transcript counts and progeny yields have been observed with influenza, lymphocytic choriomeningitis, arenavirus, foot-and-mouth disease virus, Herpes simplex virus 1, murine gammaherpesvirus 68 and Dengue and Zika virus [10][11][12][13][14][15][16][17]. Studies with Influenza A virus revealed variability in translation and assembly of progeny particles [18,19].…”

Section: Introductionmentioning

confidence: 99%

Cell-to-cell and genome-to-genome variability of Adenovirus transcription tuned by the cell cycle

Suomalainen

Prasad

Kannan

et al. 2020

Preprint

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These authors contributed equally to this work. Abstract In clonal cultures, not all cells are equally susceptible to virus infection. Underlying mechanisms of infection variability are poorly understood. Here, we developed imagebased single cell measurements to scrutinize the heterogeneity of adenovirus (AdV) infection. AdV delivers, transcribes and replicates a linear double-stranded DNA genome in the nucleus. We measured the abundance of viral transcripts by singlemolecule RNA fluorescence in situ hybridization (FISH), and the incoming ethynyldeoxy-cytidine (EdC)-tagged viral genome by copper(I)-catalyzed azide-alkyne cycloaddition (click) reaction. The early transcripts increased from 2-12 hours, the late ones from 12-23 hours post infection (pi), indicating distinct accumulation kinetics. Surprisingly, the expression of the immediate early transactivator gene E1A only moderately correlated with the number of viral genomes in the cell nucleus, although the incoming viral DNA remained largely intact until 7 hours pi. Genome-to-genome heterogeneity was found at the level of viral transcription, as indicated by colocalization with the large intron containing early region E4 transcripts, uncorrelated to the multiplicity of incoming genomes in the nucleus. In accordance, individual genomes exhibited heterogeneous replication activity, as shown by single-strand DNA-FISH and immunocytochemistry. These results indicate that the variability in viral gene expression and replication are not due to defective genomes but due to host cell heterogeneity. By analyzing the cell cycle state, we found that G1 cells exhibited the highest E1A expression, and significantly increased the correlation between E1A expression and viral genome copy numbers. This combined imagebased single molecule procedure is ideally suited to explore the cell-to-cell variability in viral infection, including transcriptional activators and repressors, RNA splicing mechanisms, and the impact of the 3-dimensional nuclear topology on gene regulation. 3 Author SummaryAdenoviruses (AdV) are ubiquitous pathogens in vertebrates. They persist in infected people, and cause unpredictable outbreaks, morbidity and mortality across the globe.Here we report that the common human AdV type C5 (AdV-C5) gives rise to considerable infection variability at the level of single cells in culture, and that a major underlying reason is the cell-to-cell heterogeneity. By combining sensitive single molecule in situ technology for detecting the incoming viral DNA and newly synthesized viral transcripts we show that viral gene expression is heterogeneous between infected human cells, as well as individual genomes. We report a moderate correlation between the number of viral genomes in the nucleus and immediate early E1A transcripts. This correlation is increased in the G1 phase of the cell cycle, where the E1A transcripts were found to be more abundant than in any other cell cycle phase. Our results demonstrate the importance of cell-to-cell variability measurements for understand...

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“…Alternatively, viruses might enter the body from the seawater via the cloaca, replicate in the distal parts of the intestine and again are excreted by feces, as previously suggested (Scholtissek, 1985). Since methods to label influenza virus proteins with fluorophores are now available (Fukuyama et al, 2015;Vahey and Fletcher, 2019) the hypothesis is now amenable to experimental verification by following expression of viral proteins in various tissues and cells after oral infection of birds.…”

Section: Discussionmentioning

confidence: 96%

Mimicking the passage of avian influenza viruses through the gastrointestinal tract of chickens

Han

Bertzbach

Veit

2019

Veterinary Microbiology

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In contrast to human influenza viruses that replicate in the respiratory tract and are airborne transmitted, avian viruses also replicate in gut epithelial cells and are transmitted via the fecal-oral route. On this route, the virus is exposed to destructive fluids of the digestive tract, which are acidic and contain the proteases pepsin (gizzard) or chymotrypsin and trypsin (intestine). Only the latter enzyme activates virus by cleaving hemagglutinin (HA) into HA 1 and HA 2 subunits.We mimicked the passage of viruses through the gastrointestinal tract by treating them with digestive fluids from chicken and determined titers and integrity of HA by western-blot. Gizzard fluid completely inactivated virions and degrades HA even at a high dilution, but only if the pH was kept acidic. If the fluid is diluted with neutral buffer (mimicking virus uptake with seawater) particles were more resistant. Virions containing an uncleaved HA were even activated suggesting that gastric juice contains a trypsin-like protease. Undiluted intestinal fluid inactivated particles and destroyed HA, but diluted fluid activated virions. A virus isolated from the duck´s intestine is more tolerant against intestinal fluid compared to fowl plague virus suggesting that the former is better adapted to grow in the intestine. We also demonstrate that influenza viruses replicate to high titers in a novel chicken epithelial gut cell line. While viruses with a monobasic HA cleavage site require addition of trypsin, these cells effectively process HA with a polybasic cleavage site, which could be blocked with an inhibitor of the cellular furin protease.

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Low-Fidelity Assembly of Influenza A Virus Promotes Escape from Host Cells

Cited by 70 publications

References 78 publications

DNA-Packing Portal and Capsid-Associated Tegument Complexes in the Tumor Herpesvirus KSHV

DNA-Packing Portal and Capsid-Associated Tegument Complexes in the Tumor Herpesvirus KSHV

Cell-to-cell and genome-to-genome variability of Adenovirus transcription tuned by the cell cycle

Mimicking the passage of avian influenza viruses through the gastrointestinal tract of chickens

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