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The Journal of General Virology Mar 2021A long-standing paradigm in virology was that non-enveloped viruses induce cell lysis to release progeny virions. However, emerging evidence indicates that some... (Review)
Review
A long-standing paradigm in virology was that non-enveloped viruses induce cell lysis to release progeny virions. However, emerging evidence indicates that some non-enveloped viruses exit cells without inducing cell lysis, while others engage both lytic and non-lytic egress mechanisms. Enteric viruses are transmitted via the faecal-oral route and are important causes of a wide range of human infections, both gastrointestinal and extra-intestinal. Virus cellular egress, when fully understood, may be a relevant target for antiviral therapies, which could minimize the public health impact of these infections. In this review, we outline lytic and non-lytic cell egress mechanisms of non-enveloped enteric RNA viruses belonging to five families: , , , and . We discuss factors that contribute to egress mechanisms and the relevance of these mechanisms to virion stability, infectivity and transmission. Since most data were obtained in traditional two-dimensional cell cultures, we will further attempt to place them into the context of polarized cultures and pathogenesis. Throughout the review, we highlight numerous knowledge gaps to stimulate future research into the egress mechanisms of these highly prevalent but largely understudied viruses.
Topics: Animals; Humans; RNA Virus Infections; RNA Viruses; Virion; Virus Release
PubMed: 33560198
DOI: 10.1099/jgv.0.001557 -
Journal of Virology Mar 2012Our knowledge regarding the contribution of the innate immune system in recognizing and subsequently initiating a host response to an invasion of RNA virus has been... (Review)
Review
Our knowledge regarding the contribution of the innate immune system in recognizing and subsequently initiating a host response to an invasion of RNA virus has been rapidly growing over the last decade. Descriptions of the receptors involved and the molecular mechanisms they employ to sense viral pathogen-associated molecular patterns have emerged in great detail. This review presents an overview of our current knowledge regarding the receptors used to detect RNA virus invasion, the molecular structures these receptors sense, and the involved downstream signaling pathways.
Topics: Animals; Humans; Immunity, Innate; RNA Virus Infections; RNA Viruses; Receptors, Immunologic
PubMed: 22258243
DOI: 10.1128/JVI.05738-11 -
Uirusu 2016Endogenous bornavirus-like elements (EBLs) are ancient bornavirus-derived sequence in the genomes of eukaryotes. Expression profile of EBLs suggests that, although most... (Review)
Review
Endogenous bornavirus-like elements (EBLs) are ancient bornavirus-derived sequence in the genomes of eukaryotes. Expression profile of EBLs suggests that, although most of the EBLs in mammalian genomes have lost their coding potential, many of them are transcribed in a cell-type specific or ubiquitous manner. This observation leads us to speculate that EBLs may have functions in their host cells. Here we describe possible functions of EBLs and their evolutionary significance. Our recent studies revealed that EBLs in some mammals, including humans, play critical roles in viral infection as either RNAs or proteins in previously undescribed mechanisms. Considering that species having EBLs in their genomes appear to be relatively resistance to BDV-mediated pathogenesis, endogenization of RNA viruses might be an evolutionarily inevitable event in the adaptation of hosts to the viruses.
Topics: Adaptation, Physiological; Animals; Biological Evolution; Bornaviridae; Genome; Humans; RNA Stability; RNA Virus Infections; RNA Viruses; RNA, Viral; Transcription, Genetic; Virus Replication
PubMed: 28484177
DOI: 10.2222/jsv.66.39 -
Viruses Apr 2022(NoNRV1) has been reported previously in the fungus , but its biological effects on its host are unknown. In this work, we isolated a strain 9-1 of from a...
(NoNRV1) has been reported previously in the fungus , but its biological effects on its host are unknown. In this work, we isolated a strain 9-1 of from a chrysanthemum leaf and identified NoNRV1 infection in the isolated strain. The genome sequence of NoNRV1 identified here is highly homologous to that of the isolate HN-21 of NoNRV1 previously reported; thus, we tentatively designated the newly identified NoNRV1 as NoNRV1-ZJ. Drug treatment with Ribavirin successfully removed NoNRV1-ZJ from the strain 9-1, which provided us with an ideal control to determine the biological impacts of NoNRV1 infection on host fungi. By comparing the virus-carrying (9-1) and virus-cured (9-1C) strains, our results indicated that infection with NoNRV1 promoted the pigmentation of the host cells, while it had no discernable effects on host growth on potato dextrose agar plates when subjected to osmotic or oxidative stress. Interestingly, we observed inhibitory impacts of virus infection on the thermotolerance of and the pathogenicity of the host fungus in cotton leaves. Collectively, our work provides clear evidence of the biological relevance of NoNRV1 infection in , including pigmentation, hypovirulence, and thermotolerance.
Topics: Fungal Viruses; Phylogeny; Plant Diseases; RNA Viruses; Virulence
PubMed: 35458525
DOI: 10.3390/v14040795 -
Journal of Microbiology and... Jul 2014Plant pathogenic RNA viruses are present in a variety of plant-based foods. When ingested by humans, these viruses can survive the passage through the digestive tract,...
Plant pathogenic RNA viruses are present in a variety of plant-based foods. When ingested by humans, these viruses can survive the passage through the digestive tract, and are frequently detected in human feces. Kimchi is a traditional fermented Korean food made from cabbage or vegetables, with a variety of other plant-based ingredients, including ground red pepper and garlic paste. We analyzed microbial metatranscriptome data from kimchi at five fermentation stages to identify plant RNA virus-derived sequences. We successfully identified a substantial amount of plant RNA virus sequences, especially during the early stages of fermentation: 23.47% and 16.45% of total clean reads on days 7 and 13, respectively. The most abundant plant RNA virus sequences were from pepper mild mottle virus, a major pathogen of red peppers; this constituted 95% of the total RNA virus sequences identified throughout the fermentation period. We observed distinct sequencing read-depth distributions for plant RNA virus genomes, possibly implying intrinsic and/or technical biases during the metatranscriptome generation procedure. We also identified RNA virus sequences in publicly available microbial metatranscriptome data sets. We propose that metatranscriptome data may serve as a valuable resource for RNA virus detection, and a systematic screening of the ingredients may help prevent the use of virus-infected low-quality materials for food production.
Topics: Brassica; Fermentation; Gene Expression Profiling; Metagenomics; RNA Viruses; RNA, Viral; Sequence Analysis, RNA
PubMed: 24836186
DOI: 10.4014/jmb.1404.04017 -
Uirusu 2020Negative-strand RNA viruses do not possess a rigid viral shell, and their structures are flexible and fragile. We have applied various electron microscopies to analyze...
Negative-strand RNA viruses do not possess a rigid viral shell, and their structures are flexible and fragile. We have applied various electron microscopies to analyze the morphologies of influenza and Ebola virus. Our studies have revealed the native interior and exterior ultrastructures of influenza virus as well as the assembly of Ebola virus core in atomic detail.
Topics: Ebolavirus; Humans; Influenza, Human; Nucleocapsid; Orthomyxoviridae; RNA Viruses; RNA, Viral
PubMed: 33967118
DOI: 10.2222/jsv.70.91 -
Current Opinion in Biotechnology Oct 1992Successful recovery of RNA viruses and functional RNA replicons from cDNA has greatly facilitated molecular genetic analyses of viral proteins and cis-regulatory... (Review)
Review
Successful recovery of RNA viruses and functional RNA replicons from cDNA has greatly facilitated molecular genetic analyses of viral proteins and cis-regulatory elements. This technology allows the use of RNA virus replication machinery to express heterologous sequences. Both positive-strand and negative-strand animal RNA viruses have been engineered to produce chimeric viruses expressing protective epitopes from other pathogens and for transient expression of heterologous sequences.
Topics: Alphavirus; Biotechnology; Gene Expression; Genetic Engineering; Orthomyxoviridae; RNA Viruses; RNA, Viral
PubMed: 1369402
DOI: 10.1016/0958-1669(92)90081-s -
The Journal of General Virology Aug 2022Virus infection is a process that requires combined contributions from both virus and host factors. For this process to be efficient within the crowded host environment,... (Review)
Review
Virus infection is a process that requires combined contributions from both virus and host factors. For this process to be efficient within the crowded host environment, viruses have evolved ways to manipulate and reorganize host structures to produce cellular microenvironments. Positive-strand RNA virus replication and assembly occurs in association with cytoplasmic membranes, causing a reorganization of these membranes to create microenvironments that support viral processes. Similarities between virus-induced membrane domains and cellular organelles have led to the description of these structures as virus replication organelles (vRO). Electron microscopy analysis of vROs in positive-strand RNA virus infected cells has revealed surprising morphological similarities between genetically diverse virus species. For all positive-strand RNA viruses, vROs can be categorized into two groups: those that make invaginations into the cellular membranes (In-vRO), and those that cause the production of protrusions from cellular membranes (Pr-vRO), most often in the form of double membrane vesicles (DMVs). In this review, we will discuss the current knowledge on the structure and biogenesis of these two different vRO classes as well as comparing morphology and function of vROs between various positive-strand RNA viruses. Finally, we will discuss recent studies describing pharmaceutical intervention in vRO formation as an avenue to control virus infection.
Topics: Cell Membrane; Hepacivirus; Organelles; Positive-Strand RNA Viruses; RNA, Viral; Virus Replication
PubMed: 35976091
DOI: 10.1099/jgv.0.001773 -
PLoS Genetics Oct 2019Viral quasispecies refers to a population structure that consists of extremely large numbers of variant genomes, termed mutant spectra, mutant swarms or mutant clouds....
Viral quasispecies refers to a population structure that consists of extremely large numbers of variant genomes, termed mutant spectra, mutant swarms or mutant clouds. Fueled by high mutation rates, mutants arise continually, and they change in relative frequency as viral replication proceeds. The term quasispecies was adopted from a theory of the origin of life in which primitive replicons) consisted of mutant distributions, as found experimentally with present day RNA viruses. The theory provided a new definition of wild type, and a conceptual framework for the interpretation of the adaptive potential of RNA viruses that contrasted with classical studies based on consensus sequences. Standard clonal analyses and deep sequencing methodologies have confirmed the presence of myriads of mutant genomes in viral populations, and their participation in adaptive processes. The quasispecies concept applies to any biological entity, but its impact is more evident when the genome size is limited and the mutation rate is high. This is the case of the RNA viruses, ubiquitous in our biosphere, and that comprise many important pathogens. In virology, quasispecies are defined as complex distributions of closely related variant genomes subjected to genetic variation, competition and selection, and that may act as a unit of selection. Despite being an integral part of their replication, high mutation rates have an upper limit compatible with inheritable information. Crossing such a limit leads to RNA virus extinction, a transition that is the basis of an antiviral design termed lethal mutagenesis.
Topics: Evolution, Molecular; High-Throughput Nucleotide Sequencing; Mutation Rate; Origin of Life; Quasispecies; RNA Viruses; Viral Vaccines; Virus Replication
PubMed: 31622336
DOI: 10.1371/journal.pgen.1008271 -
Trends in Biotechnology Dec 2018CRISPR-Cas13a is an efficient RNA targeting and editing tool characterized recently in prokaryotes. This system can be recruited to engineer resistance against plant RNA... (Review)
Review
CRISPR-Cas13a is an efficient RNA targeting and editing tool characterized recently in prokaryotes. This system can be recruited to engineer resistance against plant RNA viruses and regulate gene expression. We discuss some important achievements in using the CRISPR-Cas13a system to confer resistance against plant RNA viruses.
Topics: CRISPR-Cas Systems; Disease Resistance; Gene Editing; Plant Diseases; Plant Viruses; Plants, Genetically Modified; RNA Viruses
PubMed: 29903474
DOI: 10.1016/j.tibtech.2018.05.005