scholarly journals Exploitation of Host Factors and Cellular Pathways by Tombusviruses for the Biogenesis of the Viral Replication Organelles

Proceedings ◽  
2020 ◽  
Vol 50 (1) ◽  
pp. 18
Author(s):  
Peter D. Nagy
Keyword(s):  
Viral Replication ◽  
Rna Viruses ◽  
Plant Viruses ◽  
Complex Nature ◽  
Host Proteins ◽  
Yeast Saccharomyces Cerevisiae ◽  
Host Interactions ◽  
Genome Wide ◽  
Show Evidence ◽  
Surrogate Host

Plus-stranded RNA viruses recruit cellular vesicles and co-opt cellular proteins involved in cellular metabolism and lipid biosynthesis to build viral replicase complexes (VRCs) within the large viral replication compartments. We use tombusviruses (TBSV), which are small (+)RNA viruses, as model plant viruses to study virus replication, recombination, and virus–host interactions using yeast (Saccharomyces cerevisiae) as a surrogate host. Several systematic genome-wide screens and global proteomic and lipidomic approaches have led to the identification of ~500 host proteins/genes that are implicated in TBSV replication. We characterized the role of two-dozen co-opted host proteins, sterols, and phosphatidylethanolamine in tombusvirus VRC assembly and viral RNA synthesis. We provide evidence on the critical roles of phosphoinositides and co-opted membrane-shaping proteins in VRC formation. We also present data that tombusviruses hijack the glycolytic and fermentation pathways to obtain ATP, which is required for the biogenesis of the replication compartment. Finally, we show evidence that TBSV usurps COPII and endosomal vesicles to form a unique microenvironment involving peroxisomes and endoplasmic reticulum (ER) to support viral replication. These new insights highlight the amazingly complex nature of virus-host interactions.

Replication of positive-strand RNA viruses in plants: contact points between plant and virus components

2005 ◽  
Vol 83 (12) ◽  
pp. 1529-1549 ◽  
Author(s):  
Hélène Sanfaçon
Keyword(s):  
Viral Replication ◽  
Rna Viruses ◽  
Plant Viruses ◽  
Host Proteins ◽  
Positive Strand ◽  
Viral Genomes ◽  
Contact Points ◽  
Protein Membrane ◽  
Positive Strand Rna

Positive-strand RNA viruses constitute the largest group of plant viruses and have an important impact on world agriculture. These viruses have small genomes that encode a limited number of proteins and depend on their hosts to complete the various steps of their replication cycle. In this review, the contact points between positive-strand RNA plant viruses and their hosts, which are necessary for the translation and replication of the viral genomes, are discussed. Special emphasis is placed on the description of viral replication complexes that are associated with specific membranous compartments derived from plant intracellular membranes and contain viral RNAs and proteins as well as a variety of host proteins. These complexes are assembled via an intricate network of protein–protein, protein–membrane, and protein–RNA interactions. The role of host factors in regulating the assembly, stability, and activity of viral replication complexes are also discussed.

scholarly journals Integrative time-scale and multi-omic analysis of host-responses to Hop stunt viroid infection

2022 ◽  
Author(s):  
Joan Marquez-Molins ◽  
Pascual Villalba-Bermell ◽  
Julia Corell-Sierra ◽  
Vicente Pallas ◽  
Gustavo Gomez
Keyword(s):  
Regulatory Networks ◽  
Initial Response ◽  
Host Responses ◽  
Complex Nature ◽  
Regulatory Pathways ◽  
Host Interactions ◽  
Stunt Viroid ◽  
Genome Wide ◽  
Hop Stunt Viroid ◽  
Viroid Infection

Constricted by an extreme biological simplicity, viroids are compelled to subvert host regulatory networks in order to accomplish their infectious process. Most of the studies focused on the response to viroid infection have only addressed a specific host regulatory level and considered a unique infection time. Thus, much remains to be done if we want to understand the temporal evolution and complex nature of viroid-host interactions. Here we present an integrative analysis of the timing and intensity of the genome-wide alterations in cucumber plants infected with Hop stunt viroid (HSVd). Differential host transcriptome, sRNAnome and methylome were integrated to determine the temporal response to viroid-infection. Our results support that HSVd promotes a dynamic redesign of the cucumber regulatory pathways predominantly affecting specific regulatory layers at different infection phases. Remarkably, the initial response was characterized by a reconfiguration of the host transcriptome by differential exon usage, followed by a predominant down-regulation of the transcriptional activity possibly modulated by the host epigenetic changes associated to infection and characterized by an increased hypermethylation. The silencing of at least three cucumber transcripts potential targets of vd-sRNAs was also observed. The alteration in host sRNA and miRNA metabolism was marginal. We expect that these data constituting the first comprehensive map of the cucumber-response to HSVd could contribute to elucidate the molecular basis of the host alterations triggered by viroid infection.

scholarly journals Novel Mechanism of Regulation of Tomato Bushy Stunt Virus Replication by Cellular WW-Domain Proteins

2014 ◽  
Vol 89 (4) ◽  
pp. 2064-2079 ◽  
Author(s):  
Daniel Barajas ◽  
Nikolay Kovalev ◽  
Jun Qin ◽  
Peter D. Nagy
Keyword(s):  
Viral Replication ◽  
Rna Viruses ◽  
Viral Rna ◽  
Replication Proteins ◽  
Restriction Factors ◽  
Host Proteins ◽  
Ww Domain ◽  
Infected Cells ◽  
Viral Replicase ◽  
Domain Protein

ABSTRACTReplication of (+)RNA viruses depends on several co-opted host proteins but is also under the control of cell-intrinsic restriction factors (CIRFs). By using tombusviruses, small model viruses of plants, we dissect the mechanism of inhibition of viral replication by cellular WW-domain-containing proteins, which act as CIRFs. By using fusion proteins between the WW domain and the p33 replication protein, we show that the WW domain inhibits the ability of p33 to bind to the viral RNA and to other p33 and p92 replication proteins leading to inhibition of viral replication in yeast and in a cell extract. Overexpression of WW-domain protein in yeast also leads to reduction of several co-opted host factors in the viral replicase complex (VRC). These host proteins, such as eEF1A, Cdc34 E2 ubiquitin-conjugating enzyme, and ESCRT proteins (Bro1p and Vps4p), are known to be involved in VRC assembly. Simultaneous coexpression of proviral cellular factors with WW-domain protein partly neutralizes the inhibitory effect of the WW-domain protein. We propose that cellular WW-domain proteins act as CIRFs and also as regulators of tombusvirus replication by inhibiting the assembly of new membrane-bound VRCs at the late stage of infection. We suggest that tombusviruses could sense the status of the infected cells via the availability of cellular susceptibility factors versus WW-domain proteins for binding to p33 replication protein that ultimately controls the formation of new VRCs. This regulatory mechanism might explain how tombusviruses could adjust the efficiency of RNA replication to the limiting resources of the host cells during infections.IMPORTANCEReplication of positive-stranded RNA viruses, which are major pathogens of plants, animals, and humans, is inhibited by several cell-intrinsic restriction factors (CIRFs) in infected cells. We define here the inhibitory roles of the cellular Rsp5 ubiquitin ligase and its WW domain in plant-infecting tombusvirus replication in yeast cells andin vitrousing purified components. The WW domain of Rsp5 binds to the viral RNA-binding sites of p33 and p92 replication proteins and blocks the ability of these viral proteins to use the viral RNA for replication. The WW domain also interferes with the interaction (oligomerization) of p33 and p92 that is needed for the assembly of the viral replicase. Moreover, WW domain also inhibits the subversion of several cellular proteins into the viral replicase, which otherwise play proviral roles in replication. Altogether, Rsp5 is a CIRF against a tombusvirus, and it possibly has a regulatory function during viral replication in infected cells.

scholarly journals Recent Advances in Bunyavirus Reverse Genetics Research: Systems Development, Applications, and Future Perspectives

2021 ◽  
Vol 12 ◽  
Author(s):  
Fuli Ren ◽  
Shu Shen ◽  
Qiongya Wang ◽  
Gang Wei ◽  
Chaolin Huang ◽  
...  
Keyword(s):  
Viral Replication ◽  
Reverse Genetics ◽  
Rna Viruses ◽  
Current Knowledge ◽  
Evolutionary Process ◽  
Replication Cycle ◽  
Necessary Condition ◽  
Emerging Viruses ◽  
Host Interactions ◽  
Genetics Research

Bunyaviruses are members of the Bunyavirales order, which is the largest group of RNA viruses, comprising 12 families, including a large group of emerging and re-emerging viruses. These viruses can infect a wide variety of species worldwide, such as arthropods, protozoans, plants, animals, and humans, and pose substantial threats to the public. In view of the fact that a better understanding of the life cycle of a highly pathogenic virus is often a precondition for developing vaccines and antivirals, it is urgent to develop powerful tools to unravel the molecular basis of the pathogenesis. However, biosafety level −3 or even −4 containment laboratory is considered as a necessary condition for working with a number of bunyaviruses, which has hampered various studies. Reverse genetics systems, including minigenome (MG), infectious virus-like particle (iVLP), and infectious full-length clone (IFLC) systems, are capable of recapitulating some or all steps of the viral replication cycle; among these, the MG and iVLP systems have been very convenient and effective tools, allowing researchers to manipulate the genome segments of pathogenic viruses at lower biocontainment to investigate the viral genome transcription, replication, virus entry, and budding. The IFLC system is generally developed based on the MG or iVLP systems, which have facilitated the generation of recombinant infectious viruses. The MG, iVLP, and IFLC systems have been successfully developed for some important bunyaviruses and have been widely employed as powerful tools to investigate the viral replication cycle, virus–host interactions, virus pathogenesis, and virus evolutionary process. The majority of bunyaviruses is generally enveloped negative-strand RNA viruses with two to six genome segments, of which the viruses with bipartite and tripartite genome segments have mostly been characterized. This review aimed to summarize current knowledge on reverse genetic studies of representative bunyaviruses causing severe diseases in humans and animals, which will contribute to the better understanding of the bunyavirus replication cycle and provide some hints for developing designed antivirals.

scholarly journals Chikungunya and Zika Viruses: Co-Circulation and the Interplay between Viral Proteins and Host Factors

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 448
Author(s):  
Sineewanlaya Wichit ◽  
Nuttamonpat Gumpangseth ◽  
Rodolphe Hamel ◽  
Sakda Yainoy ◽  
Siwaret Arikit ◽  
...  
Keyword(s):  
Antiviral Drug ◽  
Virus Transmission ◽  
Antiviral Agent ◽  
Viral Proteins ◽  
Targeted Therapeutics ◽  
Limited Information ◽  
Mosquito Vectors ◽  
Host Proteins ◽  
Host Interactions ◽  
Viral Host Interactions

Chikungunya and Zika viruses, both transmitted by mosquito vectors, have globally re-emerged over for the last 60 years and resulted in crucial social and economic concerns. Presently, there is no specific antiviral agent or vaccine against these debilitating viruses. Understanding viral–host interactions is needed to develop targeted therapeutics. However, there is presently limited information in this area. In this review, we start with the updated virology and replication cycle of each virus. Transmission by similar mosquito vectors, frequent co-circulation, and occurrence of co-infection are summarized. Finally, the targeted host proteins/factors used by the viruses are discussed. There is an urgent need to better understand the virus–host interactions that will facilitate antiviral drug development and thus reduce the global burden of infections caused by arboviruses.

scholarly journals Viruses go modular

2020 ◽  
Vol 295 (14) ◽  
pp. 4604-4616 ◽  
Author(s):  
Ariel Shepley-McTaggart ◽  
Hao Fan ◽  
Marius Sudol ◽  
Ronald N. Harty
Keyword(s):  
Hippo Pathway ◽  
Host Proteins ◽  
Dna Viruses ◽  
Ww Domain ◽  
Ww Domains ◽  
Host Interactions ◽  
New Class ◽  
Domain Interactions ◽  
Molecular Aspects ◽  
The Hippo Pathway

The WW domain is a modular protein structure that recognizes the proline-rich Pro-Pro-x-Tyr (PPxY) motif contained in specific target proteins. The compact modular nature of the WW domain makes it ideal for mediating interactions between proteins in complex networks and signaling pathways of the cell (e.g. the Hippo pathway). As a result, WW domains play key roles in a plethora of both normal and disease processes. Intriguingly, RNA and DNA viruses have evolved strategies to hijack cellular WW domain–containing proteins and thereby exploit the modular functions of these host proteins for various steps of the virus life cycle, including entry, replication, and egress. In this review, we summarize key findings in this rapidly expanding field, in which new virus-host interactions continue to be identified. Further unraveling of the molecular aspects of these crucial virus-host interactions will continue to enhance our fundamental understanding of the biology and pathogenesis of these viruses. We anticipate that additional insights into these interactions will help support strategies to develop a new class of small-molecule inhibitors of viral PPxY-host WW-domain interactions that could be used as antiviral therapeutics.

scholarly journals Povidone-Iodine Attenuates Viral Replication in Ocular Cells: Implications for Ocular Transmission of RNA Viruses

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 753
Author(s):  
Sneha Singh ◽  
Onkar B. Sawant ◽  
Shahzad I. Mian ◽  
Ashok Kumar
Keyword(s):  
Epithelial Cells ◽  
Viral Replication ◽  
Povidone Iodine ◽  
Rna Viruses ◽  
Retinal Pigment ◽  
Retinal Pigment Epithelial Cells ◽  
Host Cells ◽  
Eye Banking ◽  
Antiviral Effects ◽  
Infected Cells

Several RNA viruses, including SARS-CoV-2, can infect or use the eye as an entry portal to cause ocular or systemic diseases. Povidone-Iodine (PVP-I) is routinely used during ocular surgeries and eye banking as a cost-effective disinfectant due to its broad-spectrum antimicrobial activity, including against viruses. However, whether PVP-I can exert antiviral activities in virus-infected cells remains elusive. In this study, using Zika (ZIKV) and Chikungunya (CHIKV) virus infection of human corneal and retinal pigment epithelial cells, we report antiviral mechanisms of PVP-I. Our data showed that PVP-I, even at the lowest concentration (0.01%), drastically reduced viral replication in corneal and retinal cells without causing cellular toxicity. Antiviral effects of PVP-I against ZIKV and CHIKV were mediated by direct viral inactivation, thus attenuating the ability of the virus to infect host cells. Moreover, one-minute PVP-I exposure of infected ocular cells drastically reduced viral replication and the production of infectious progeny virions. Furthermore, viral-induced (CHIKV) expression of inflammatory genes (TNF-α, IL-6, IL-8, and IL1β) were markedly reduced in PVP-I treated corneal epithelial cells. Together, our results demonstrate potent antiviral effects of PVP-I against ZIKV and CHIKV infection of ocular cells. Thus, a low dose of PVP-I can be used during tissue harvesting for corneal transplants to prevent potential transmission of RNA viruses via infected cells.

scholarly journals Network-Guided Discovery of Influenza Virus Replication Host Factors

mBio ◽  
2018 ◽  
Vol 9 (6) ◽  
Author(s):  
Emily E. Ackerman ◽  
Eiryo Kawakami ◽  
Manami Katoh ◽  
Tokiko Watanabe ◽  
Shinji Watanabe ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Viral Replication ◽  
Virus Replication ◽  
Drug Targets ◽  
Antiviral Drug ◽  
Viral Proteins ◽  
Host Factors ◽  
Ppi Network ◽  
Host Proteins ◽  
Influenza Virus Replication

ABSTRACTThe positions of host factors required for viral replication within a human protein-protein interaction (PPI) network can be exploited to identify drug targets that are robust to drug-mediated selective pressure. Host factors can physically interact with viral proteins, be a component of virus-regulated pathways (where proteins do not interact with viral proteins), or be required for viral replication but unregulated by viruses. Here, we demonstrate a method of combining human PPI networks with virus-host PPI data to improve antiviral drug discovery for influenza viruses by identifying target host proteins. Analysis shows that influenza virus proteins physically interact with host proteins in network positions significant for information flow, even after the removal of known abundance-degree bias within PPI data. We have isolated a subnetwork of the human PPI network that connects virus-interacting host proteins to host factors that are important for influenza virus replication without physically interacting with viral proteins. The subnetwork is enriched for signaling and immune processes distinct from those associated with virus-interacting proteins. Selecting proteins based on subnetwork topology, we performed an siRNA screen to determine whether the subnetwork was enriched for virus replication host factors and whether network position within the subnetwork offers an advantage in prioritization of drug targets to control influenza virus replication. We found that the subnetwork is highly enriched for target host proteins—more so than the set of host factors that physically interact with viral proteins. Our findings demonstrate that network positions are a powerful predictor to guide antiviral drug candidate prioritization.IMPORTANCEIntegrating virus-host interactions with host protein-protein interactions, we have created a method using these established network practices to identify host factors (i.e., proteins) that are likely candidates for antiviral drug targeting. We demonstrate that interaction cascades between host proteins that directly interact with viral proteins and host factors that are important to influenza virus replication are enriched for signaling and immune processes. Additionally, we show that host proteins that interact with viral proteins are in network locations of power. Finally, we demonstrate a new network methodology to predict novel host factors and validate predictions with an siRNA screen. Our results show that integrating virus-host proteins interactions is useful in the identification of antiviral drug target candidates.

An aqueous two-phase system to pre-purify a heterologously produced siderophore

TECHNOLOGY ◽  
2016 ◽  
Vol 04 (03) ◽  
pp. 135-138
Author(s):  
Mahmoud Kamal Ahmadi ◽  
Samar Fawaz ◽  
Blaine A. Pfeifer
Keyword(s):  
Escherichia Coli ◽  
Natural Products ◽  
Cell Growth ◽  
Complex Nature ◽  
Phase System ◽  
Heterologous Production ◽  
Two Phase ◽  
Aqueous Two Phase System ◽  
Purification System ◽  
Surrogate Host

Natural products span broad activities and applications; however, their access and production are often limited by native cellular sources. As a result, the heterologous production of a siderophore termed yersiniabactin (Ybt) was completed using the surrogate host Escherichia coli. Post-production and purification steps are complicated by the complex nature of most media used for cell growth, prompting the development in this work of an aqueous two-phase pre-purification system capable of rapidly and simply enhancing the concentration of the target Ybt compound.

scholarly journals Gain-of-function genetic screening identifies the antiviral function of TMEM120A via STING activation

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Shuo Li ◽  
Nianchao Qian ◽  
Chao Jiang ◽  
Wenhong Zu ◽  
Anthony Liang ◽  
...  
Keyword(s):  
Gain Of Function ◽  
Zikv Infection ◽  
Embryonic Fibroblasts ◽  
Antiviral Signaling ◽  
Host Interactions ◽  
Interferon Stimulated Genes ◽  
Genome Wide ◽  
Primary Mouse ◽  
Antiviral Function ◽  
Intermediate Compartment

AbstractZika virus (ZIKV) infection can be associated with neurological pathologies, such as microcephaly in newborns and Guillain-Barre syndrome in adults. Effective therapeutics are currently not available. As such, a comprehensive understanding of virus-host interactions may guide the development of medications for ZIKV. Here we report a human genome-wide overexpression screen to identify host factors that regulate ZIKV infection and find TMEM120A as a ZIKV restriction factor. TMEM120A overexpression significantly inhibits ZIKV replication, while TMEM120A knockdown increases ZIKV infection in cell lines. Moreover, Tmem120a knockout in mice facilitates ZIKV infection in primary mouse embryonic fibroblasts (MEF) cells. Mechanistically, the antiviral activity of TMEM120A is dependent on STING, as TMEM120A interacts with STING, promotes the translocation of STING from the endoplasmic reticulum (ER) to ER-Golgi intermediate compartment (ERGIC) and enhances the phosphorylation of downstream TBK1 and IRF3, resulting in the expression of multiple antiviral cytokines and interferon-stimulated genes. In summary, our gain-of-function screening identifies TMEM120A as a key activator of the antiviral signaling of STING.

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