scholarly journals The Autophagosomes Containing Dengue Virus Proteins and Full-Length Genomic RNA Are Infectious

Viruses ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 2034
Author(s):  
Shan-Ying Wu ◽  
Yu-Lun Chen ◽  
Ying-Ray Lee ◽  
Chiou-Feng Lin ◽  
Sheng-Hui Lan ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Full Length ◽  
Genomic Rnas ◽  
Double Membrane ◽  
Transmission Electron ◽  
Viral Particles ◽  
Autophagic Degradation ◽  
Infected Cells ◽  
Intracellular Vesicles ◽  
Secretory Autophagy

Autophagic machinery is involved in selective and non-selective recruitment as well as degradation or exocytosis of cargoes, including pathogens. Dengue virus (DENV) infectioninduces autophagy that enhances virus replication and vesicle release to evade immune systemsurveillance. This study reveals that DENV2 induces autophagy in lung and liver cancer cells andshowed that DENV2 capsid, envelope, NS1, NS3, NS4B and host cell proinflammatory high mobilitygroup box 1 (HMGB1) proteins associated with autophagosomes which were purified by gradientcentrifugation. Capsid, NS1 and NS3 proteins showing high colocalization with LC3 protein in thecytoplasm of the infected cells were detected in the purified double-membrane autophagosome byimmunogold labeling under transmission electron microscopy. In DENV infected cells, the levels ofcapsid, envelope, NS1 and HMGB1 proteins are not significantly changed compared to the dramaticaccumulation of LC3-II and p62/SQSTM1 proteins when autophagic degradation was blocked bychloroquine, indicating that these proteins are not regulated by autophagic degradation machinery.We further demonstrated that purified autophagosomes were infectious when co-cultured withuninfected cells. Notably, these infectious autophagosomes contain DENV2 proteins, negativestrandand full-length genomic RNAs, but no viral particles. It is possible that the infectivity ofthe autophagosome originates from the full-length DENV RNA. Moreover, we reveal that DENV2promotes HMGB1 exocytosis partially through secretory autophagy. In conclusion, we are the firstto report that DENV2-induced double-membrane autophagosomes containing viral proteins andfull-length RNAs are infectious and not undergoing autophagic degradation. Our novel findingwarrants further validation of whether these intracellular vesicles undergo exocytosis to becomeinfectious autophagic vesicles.

scholarly journals Severe Acute Respiratory Syndrome Coronavirus Nonstructural Proteins 3, 4, and 6 Induce Double-Membrane Vesicles

mBio ◽  
2013 ◽  
Vol 4 (4) ◽  
Author(s):  
Megan M. Angelini ◽  
Marzieh Akhlaghpour ◽  
Benjamin W. Neuman ◽  
Michael J. Buchmeier
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Host Cell ◽  
Rna Viruses ◽  
Membrane Vesicles ◽  
Full Length ◽  
Nonstructural Proteins ◽  
Human Coronavirus ◽  
Double Membrane ◽  
Infected Cells ◽  
Proliferation Ability

ABSTRACTCoronaviruses (CoV), like other positive-stranded RNA viruses, redirect and rearrange host cell membranes for use as part of the viral genome replication and transcription machinery. Specifically, coronaviruses induce the formation of double-membrane vesicles in infected cells. Although these double-membrane vesicles have been well characterized, the mechanism behind their formation remains unclear, including which viral proteins are responsible. Here, we use transfection of plasmid constructs encoding full-length versions of the three transmembrane-containing nonstructural proteins (nsps) of the severe acute respiratory syndrome (SARS) coronavirus to examine the ability of each to induce double-membrane vesicles in tissue culture. nsp3 has membrane disordering and proliferation ability, both in its full-length form and in a C-terminal-truncated form. nsp3 and nsp4 working together have the ability to pair membranes. nsp6 has membrane proliferation ability as well, inducing perinuclear vesicles localized around the microtubule organizing center. Together, nsp3, nsp4, and nsp6 have the ability to induce double-membrane vesicles that are similar to those observed in SARS coronavirus-infected cells. This activity appears to require the full-length form of nsp3 for action, as double-membrane vesicles were not seen in cells coexpressing the C-terminal truncation nsp3 with nsp4 and nsp6.IMPORTANCEAlthough the majority of infections caused by coronaviruses in humans are relatively mild, the SARS outbreak of 2002 to 2003 and the emergence of the human coronavirus Middle Eastern respiratory syndrome (MERS-CoV) in 2012 highlight the ability of these viruses to cause severe pathology and fatality. Insight into the molecular biology of how coronaviruses take over the host cell is critical for a full understanding of any known and possible future outbreaks caused by these viruses. Additionally, since membrane rearrangement is a tactic used by all known positive-sense single-stranded RNA viruses, this work adds to that body of knowledge and may prove beneficial in the development of future therapies not only for human coronavirus infections but for other pathogens as well.

scholarly journals Characterization of a novel alloherpesvirus from Atlantic cod (Gadus morhua)

2011 ◽  
Vol 24 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Mar Marcos-Lopez ◽  
Thomas B. Waltzek ◽  
Ronald P. Hedrick ◽  
Dolores V. Baxa ◽  
Amber F. Garber ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Virus Isolation ◽  
Atlantic Cod ◽  
International Committee ◽  
Atpase Subunit ◽  
Transmission Electron ◽  
Viral Particles ◽  
Infected Cells

Alloherpesviruses affect freshwater and marine fish species. The aim of the current study was to characterize a novel alloherpesvirus in Atlantic cod ( Gadus morhua). Samples were processed for histopathology, transmission electron microscopy (TEM), virus isolation, molecular characterization, and in situ hybridization (ISH). Histopathology revealed that the infection was restricted to the gills and that it induced cytomegaly in infected cells. By TEM, numerous viral particles with morphology compatible with a herpesvirus were observed inside the cytomegalic cells. To characterize this new agent, polymerase chain reaction amplified regions of the ATPase subunit of the terminase, and DNA polymerase genes were sequenced. Phylogenetic analysis revealed strongest similarity with alloherpesviruses belonging to the genus Ictalurivirus and Salmonivirus. The ISH showed specific labeling of nuclear inclusions in the cytomegalic cells. While virus isolation was unsuccessful, the results obtained through different diagnostic tests in the present study confirm the discovery of a new alloherpesvirus affecting Atlantic cod. The authors propose the formal species designation Gadid herpesvirus 1 (GaHV-1) to be considered for approval by the International Committee on the Taxonomy of Viruses.

Viral burst size of heterotrophic prokaryotes in aquatic systems

2006 ◽  
Vol 86 (3) ◽  
pp. 613-621 ◽  
Author(s):  
Verónica Parada ◽  
Gerhard J. Herndl ◽  
Markus G. Weinbauer
Keyword(s):  
Large Scale ◽  
Burst Size ◽  
Aquatic Systems ◽  
The Past ◽  
Number Of Factors ◽  
Transmission Electron ◽  
Viral Particles ◽  
Infected Cells ◽  
Heterotrophic Prokaryotes

Viral burst size (BS), i.e. the number of viruses released during cell lysis, is a critical parameter for assessing the ecological and biogeochemical role of viruses in aquatic systems. Burst size is typically estimated by enumerating the viral particles in bacteria using transmission electron microscopy. Here, we review the average BS reported for different aquatic systems, present several hypotheses on the control of the BS and evaluate whether there are relationships between BS and bacterial activity parameters across systems. Based on reports from a variety of different aquatic environments, we calculated a mean BS of 24 and 34 for marine and freshwater environments, respectively. Generally, the BS increased with the trophic status of the environment and with the percentage of infected cells in marine populations. When diel dynamics were investigated or averages from large-scale environments were used, BS was positively related to bacterial production but no trend was detectable across systems. The across systems' finding that BS was significantly related to the frequency of infected cells (FIC) could be due to co-infection or superinfection. At any given site, BS seems to be influenced by a number of factors such as the size of the host cell and the viruses, the metabolic activity of the host and phage and host diversity. Thus, based on the available data collected over the past two decades on a variety of aquatic systems, some relations between BS and bacterial variables were detectable.

scholarly journals Rice dwarf virus is engulfed into and released via vesicular compartments in cultured insect vector cells

2008 ◽  
Vol 89 (11) ◽  
pp. 2915-2920 ◽  
Author(s):  
Taiyun Wei ◽  
Hiroyuki Hibino ◽  
Toshihiro Omura
Keyword(s):  
Brefeldin A ◽  
Virus Multiplication ◽  
Dwarf Virus ◽  
Insect Vector ◽  
Rice Dwarf Virus ◽  
Transmission Electron ◽  
Viral Particles ◽  
Infected Cells ◽  
Vector Insect ◽  
Butanedione Monoxime

Vector insect cells infected with Rice dwarf virus had vesicular compartments containing viral particles located adjacent to the viroplasm when examined by transmission electron and confocal microscopy. Such compartments were often at the periphery of infected cells. Inhibitors of vesicular transport, brefeldin A and monensin, and an inhibitor of myosin motor activity, butanedione monoxime, abolished the formation of such vesicles and prevented the release of viral particles from infected cells without significant effects on virus multiplication. Furthermore, the actin-depolymerizing drug, cytochalasin D, inhibited the formation of actin filaments without significantly interfering with formation of vesicular compartments and the release of viruses from treated cells. These results together revealed intracellular vesicular compartments as a mode for viral transport in and release from insect vector cells infected with a plant-infecting reovirus.

scholarly journals Defective Viral Genomes Alter How Sendai Virus Interacts with Cellular Trafficking Machinery, Leading to Heterogeneity in the Production of Viral Particles among Infected Cells

2018 ◽  
Vol 93 (4) ◽  
Author(s):  
Emmanuelle Genoyer ◽  
Carolina B. López
Keyword(s):  
Sendai Virus ◽  
Intracellular Localization ◽  
Antiviral Immunity ◽  
Full Length ◽  
Cellular Trafficking ◽  
Viral Genomes ◽  
Host Interactions ◽  
Viral Particles ◽  
Infected Cells ◽  
In Cells

ABSTRACTDefective viral genomes (DVGs) generated during RNA virus replication determine infection outcome by triggering innate immunity, diminishing virulence, and, in many cases, facilitating the establishment of persistent infections. Despite their critical role during virus-host interactions, the mechanisms regulating the production and propagation of DVGs are poorly understood. Visualization of viral genomes using RNA fluorescentin situhybridization revealed a striking difference in the intracellular localization of DVGs and full-length viral genomes during infections with the paramyxovirus Sendai virus. In cells enriched in full-length virus, viral genomes clustered in a perinuclear region and associated with cellular trafficking machinery, including microtubules and the GTPase Rab11a. However, in cells enriched in DVGs, defective genomes distributed diffusely throughout the cytoplasm and failed to interact with this cellular machinery. Consequently, cells enriched in full-length genomes produced both DVG- and full-length-genome-containing viral particles, while DVG-high cells poorly produced viral particles yet strongly stimulated antiviral immunity. These findings reveal the selective production of both standard and DVG-containing particles by a subpopulation of infected cells that can be differentiated by the intracellular localization of DVGs. This study highlights the importance of considering this functional heterogeneity in analyses of virus-host interactions during infection.IMPORTANCEDefective viral genomes (DVGs) generated during Sendai virus infections accumulate in the cytoplasm of some infected cells and stimulate antiviral immunity and cell survival. DVGs are packaged and released as defective particles and have a significant impact on infection outcome. We show that the subpopulation of DVG-high cells poorly engages the virus packaging and budding machinery and do not effectively produce viral particles. In contrast, cells enriched in full-length genomes are the primary producers of both standard and defective viral particles during infection. This study demonstrates heterogeneity in the molecular interactions occurring within infected cells and highlights distinct functional roles for cells as either initiators of immunity or producers and perpetuators of viral particles depending on their content of viral genomes and their intracellular localization.

Electron Microscopy of a Herpesvirus Isolated from Marek's Disease in Duck and Chicken Embryo Fibroblast Cultures

1968 ◽  
Vol 26 ◽  
pp. 222-223 ◽  
Author(s):  
Keyvan Nazerian
Keyword(s):  
Inclusion Bodies ◽  
Chicken Embryo Fibroblast ◽  
Marek's Disease ◽  
Marek’S Disease ◽  
Duck Embryo Fibroblast ◽  
Multinucleated Cells ◽  
Viral Particles ◽  
Infected Cells ◽  
And Control ◽  
Do So

A herpes-like virus has been isolated from duck embryo fibroblast (DEF) cultures inoculated with blood from Marek's disease (MD) infected birds. Cultures which contained this virus produced MD in susceptible chickens while virus negative cultures and control cultures failed to do so. This and other circumstantial evidence including similarities in properties of the virus and the MD agent implicate this virus in the etiology of MD.Histochemical studies demonstrated the presence of DNA-staining intranuclear inclusion bodies in polykarocytes in infected cultures. Distinct nucleo-plasmic aggregates were also seen in sections of similar multinucleated cells examined with the electron microscope. These aggregates are probably the same as the inclusion bodies seen with the light microscope. Naked viral particles were observed in the nucleus of infected cells within or on the edges of the nucleoplasmic aggregates. These particles measured 95-100mμ, in diameter and rarely escaped into the cytoplasm or nuclear vesicles by budding through the nuclear membrane (Fig. 1). The enveloped particles (Fig. 2) formed in this manner measured 150-170mμ in diameter and always had a densely stained nucleoid. The virus in supernatant fluids consisted of naked capsids with 162 hollow, cylindrical capsomeres (Fig. 3). Enveloped particles were not seen in such preparations.

A combined pseudoreplica-immunocytochemical technique for research and diagnostic virology

1990 ◽  
Vol 48 (3) ◽  
pp. 900-901
Author(s):  
Blayne Fritz ◽  
Stanley J. Naides ◽  
Kenneth Moore
Keyword(s):  
Phosphotungstic Acid ◽  
Immunogold Labelling ◽  
Uranyl Acetate ◽  
Distilled Water ◽  
Clinical Specimens ◽  
Tissue Sections ◽  
Specimen Retrieval ◽  
Transmission Electron ◽  
Viral Particles ◽  
Diagnostic Virology

The pseudoreplica method of staining viral particles for visualization by transmission electron microscopy is a very popular technique. The ability to concentrate clinical specimens while semi-embedding viral particles makes it especially well suited for morphologic and diagnostic virology. Immunolabelling viral particles with colloidal gold is a technique frequently employed by both research and diagnostic virologists. We have characterized a procedure which provides the advantage of both by modifying and combining pseudoreplica staining and immunogold labelling.Modification of specimen retrieval and delay of staining allows us to utilize pseudoreplica processed specimens within our standard immunogold labelling protocol. In brief, we absorbed samples onto 2% agarose, added.25% Formvar and wicked dry. We then floated the Formvar-virus film onto double distilled water, added grids and retrieved with parafilm. The Formvar-virus specimens were then treated as thin tissue sections within our standard two stage immunolabelling protocol. Following completion of immunogold labelling; each grid was negatively stained with phosphotungstic acid or uranyl acetate contrast stains.

scholarly journals Antiviral Role of Phenolic Compounds against Dengue Virus: A Review

Biomolecules ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 11
Author(s):  
Vanessa Loaiza-Cano ◽  
Laura Milena Monsalve-Escudero ◽  
Carlos da Silva Maia Bezerra Filho ◽  
Marlen Martinez-Gutierrez ◽  
Damião Pergentino de Sousa
Keyword(s):  
Phenolic Compounds ◽  
Dengue Virus ◽  
Biological Activities ◽  
Antiviral Effect ◽  
Health Concern ◽  
Host Proteins ◽  
Viral Particles ◽  
Antiviral Role ◽  
Productive Replication

Phenolic compounds have been related to multiple biological activities, and the antiviral effect of these compounds has been demonstrated in several viral models of public health concern. In this review, we show the antiviral role of phenolic compounds against dengue virus (DENV), the most widespread arbovirus globally that, after its re-emergence, has caused multiple epidemic outbreaks, especially in the last two years. Twenty phenolic compounds with anti-DENV activity are discussed, including the multiple mechanisms of action, such as those directed against viral particles or viral proteins, host proteins or pathways related to the productive replication viral cycle and the spread of the infection.

Sign in / Sign up

Export Citation Format

Share Document