scholarly journals The 5′ Untranslated Region of a Novel Infectious Molecular Clone of the Dicistrovirus Cricket Paralysis Virus Modulates Infection

2015 ◽  
Vol 89 (11) ◽  
pp. 5919-5934 ◽  
Author(s):  
Craig H. Kerr ◽  
Qing S. Wang ◽  
Kathleen Keatings ◽  
Anthony Khong ◽  
Douglas Allan ◽  
...  
Keyword(s):  
Untranslated Region ◽  
Molecular Mechanisms ◽  
Insect Cells ◽  
Infectious Clone ◽  
Virus Infectivity ◽  
Viral Translation ◽  
Content Type ◽  
Host Virus Interactions ◽  
Virus Interactions ◽  
Paralysis Virus

ABSTRACTDicistroviridaeare a family of RNA viruses that possesses a single-stranded positive-sense RNA genome containing two distinct open reading frames (ORFs), each preceded by an internal ribosome entry site that drives translation of the viral structural and nonstructural proteins, respectively. The type species,Cricket paralysis virus(CrPV), has served as a model for studying host-virus interactions; however, investigations into the molecular mechanisms of CrPV and other dicistroviruses have been limited as an established infectious clone was elusive. Here, we report the construction of an infectious molecular clone of CrPV. Transfection ofin vitro-transcribed RNA from the CrPV clone intoDrosophilaSchneider line 2 (S2) cells resulted in cytopathic effects, viral RNA accumulation, detection of negative-sense viral RNA, and expression of viral proteins. Transmission electron microscopy, viral titers, and immunofluorescence-coupled transwell assays demonstrated that infectious viral particles are released from transfected cells. In contrast, mutant clones containing stop codons in either ORF decreased virus infectivity. Injection of adultDrosophilaflies with virus derived from CrPV clones but not UV-inactivated clones resulted in mortality. Molecular analysis of the CrPV clone revealed a 196-nucleotide duplication within its 5′ untranslated region (UTR) that stimulated translation of reporter constructs. In cells infected with the CrPV clone, the duplication inhibited viral infectivity yet did not affect viral translation or RNA accumulation, suggesting an effect on viral packaging or entry. The generation of the CrPV infectious clone provides a powerful tool for investigating the viral life cycle and pathogenesis of dicistroviruses and may further understanding of fundamental host-virus interactions in insect cells.IMPORTANCEDicistroviridae, which are RNA viruses that infect arthropods, have served as a model to gain insights into fundamental host-virus interactions in insect cells. Further insights into the viral molecular mechanisms are hampered due to a lack of an established infectious clone. We report the construction of the first infectious clone of the dicistrovirus, cricket paralysis virus (CrPV). We show that transfection of the CrPV clone RNA intoDrosophilacells led to production of infectious particles that resemble natural CrPV virions and result in cytopathic effects and expression of CrPV proteins and RNA in infected cells. The CrPV clone should provide insights into the dicistrovirus life cycle and host-virus interactions in insect cells. Using this clone, we find that a 196-nucleotide duplication within the 5′ untranslated region of the CrPV clone increased viral translation in reporter constructs but decreased virus infectivity, thus revealing a balance that interplays between viral translation and replication.

scholarly journals Disruption of Stress Granule Formation by the Multifunctional Cricket Paralysis Virus 1A Protein

2016 ◽  
Vol 91 (5) ◽  
Author(s):  
Anthony Khong ◽  
Craig H. Kerr ◽  
Clarence H. L. Yeung ◽  
Kathleen Keatings ◽  
Arabinda Nayak ◽  
...  
Keyword(s):  
Virus Infection ◽  
Stress Granule ◽  
Granule Formation ◽  
Viral Translation ◽  
Content Type ◽  
Cellular Processes ◽  
Cellular Environment ◽  
Viral Yield ◽  
Infected Cells ◽  
Paralysis Virus

ABSTRACT Stress granules (SGs) are cytosolic ribonucleoprotein aggregates that are induced during cellular stress. Several viruses modulate SG formation, suggesting that SGs have an impact on virus infection. However, the mechanisms and impact of modulating SG assembly in infected cells are not completely understood. In this study, we identify the dicistrovirus cricket paralysis virus 1A (CrPV-1A) protein that functions to inhibit SG assembly during infection. Moreover, besides inhibiting RNA interference, CrPV-1A also inhibits host transcription, which indirectly modulates SG assembly. Thus, CrPV-1A is a multifunctional protein. We identify a key R146A residue that is responsible for these effects, and mutant CrPV(R146A) virus infection is attenuated in Drosophila melanogaster S2 cells and adult fruit flies and results in increased SG formation. Treatment of CrPV(R146A)-infected cells with actinomycin D, which represses transcription, restores SG assembly suppression and viral yield. In summary, CrPV-1A modulates several cellular processes to generate a cellular environment that promotes viral translation and replication. IMPORTANCE RNA viruses encode a limited set of viral proteins to modulate an array of cellular processes in order to facilitate viral replication and inhibit antiviral defenses. In this study, we identified a viral protein, called CrPV-1A, within the dicistrovirus cricket paralysis virus that can inhibit host transcription, modulate viral translation, and block a cellular process called stress granule assembly. We also identified a specific amino acid within CrPV-1A that is important for these cellular processes and that mutant viruses containing mutations of CrPV-1A attenuate virus infection. We also demonstrate that the CrPV-1A protein can also modulate cellular processes in human cells, suggesting that the mode of action of CrPV-1A is conserved. We propose that CrPV-1A is a multifunctional, versatile protein that creates a cellular environment in virus-infected cells that permits productive virus infection.

scholarly journals Cell Cycle Kinase Polo Is Controlled by a Widespread 3′ Untranslated Region Regulatory Sequence inDrosophila melanogaster

2019 ◽  
Vol 39 (15) ◽  
Author(s):  
Marta S. Oliveira ◽  
Jaime Freitas ◽  
Pedro A. B. Pinto ◽  
Ana de Jesus ◽  
Joana Tavares ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Drosophila Melanogaster ◽  
Untranslated Region ◽  
Molecular Mechanisms ◽  
Alternative Polyadenylation ◽  
Upstream Sequence ◽  
Sequence Element ◽  
Content Type ◽  
Cell Cycle Kinase

ABSTRACTAlternative polyadenylation generates transcriptomic diversity, although the physiological impact and regulatory mechanisms involved are still poorly understood. The cell cycle kinase Polo is controlled by alternative polyadenylation in the 3′ untranslated region (3′UTR), with critical physiological consequences. Here, we characterized the molecular mechanisms required forpoloalternative polyadenylation. We identified a conserved upstream sequence element (USE) close to thepoloproximal poly(A) signal. Transgenic flies without this sequence show incorrect selection ofpolopoly(A) signals with consequent downregulation of Polo expression levels and insufficient/defective activation of Polo kinetochore targets Mps1 and Aurora B. Deletion of the USE results in abnormal mitoses in neuroblasts, revealing a role for this sequencein vivo. We found that Hephaestus binds to the USE RNA and thathephaestusmutants display defects inpoloalternative polyadenylation concomitant with a striking reduction in Polo protein levels, leading to mitotic errors and aneuploidy. Bioinformatic analyses show that the USE is preferentially localized upstream of noncanonical polyadenylation signals inDrosophila melanogastergenes. Taken together, our results revealed the molecular mechanisms involved inpoloalternative polyadenylation, with remarkable physiological functions in Polo expression and activity at the kinetochores, and disclosed a newin vivofunction for USEs inDrosophila melanogaster.

scholarly journals Pathways and microRNAs bioinformatics analyses identifying possible existing therapeutics for COVID-19 treatment

2020 ◽  
Author(s):  
Laura Teodori ◽  
Piero Sestili ◽  
Valeria Madiai ◽  
Sofia Coppari ◽  
Daniele Fraternale ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
In Silico ◽  
Molecular Mechanisms ◽  
Hdac Inhibitors ◽  
Converting Enzyme ◽  
Bioinformatics Analyses ◽  
Off Label ◽  
Host Virus Interactions ◽  
Virus Interactions ◽  
Ranked List

Abstract Over 180.000 SARS-COV-2 positive cases have been confirmed in Italy as April 20, with the number of deaths exceeding 23 thousand, making Italy the second Country for world COVID-19 deaths. Such enormous occurrence of infected and dead people raises the urgent demand of effective fast available treatments to control and diminish this pandemic. Discovering the cellular/molecular mechanisms of SARS-COV-2 pathogenicity is of paramount importance to understand how the infection becomes a disease and for therapeutically approaching it. From literature data, through a bioinformatics approach, an in silico analysis was performed, to predict the putative virus targets and evidence the already available therapeutics. Literature experimental results identified angiotensin-converting enzyme ACE and Spike proteins particularly involved in COVID-19. We thus investigate on the signaling pathways modulated by the two proteins through query miRNet, the platform linking miRNAs, targets and functions. We predicted microRNAs (miRs), miR-335-5p and miR-26b-5p, as being modulated by Spike and ACE together with deacetylate histones pathway HDAC. Our results matched with the available clinical data. We hypothesize the current and EMA-approved, SARS-COV-2 off-label, HDAC inhibitors (HDACis) drugs may be repurposed to limit or block host-virus interactions. A ranked list of compounds is given that can be tested.

scholarly journals Effects of UV Radiation on the Chlorophyte Micromonas polaris Host–Virus Interactions and MpoV-45T Virus Infectivity

2021 ◽  
Vol 9 (12) ◽  
pp. 2429
Author(s):  
Charlotte Eich ◽  
Sven B. E. H. Pont ◽  
Corina P. D. Brussaard
Keyword(s):  
Uv Radiation ◽  
Algal Growth ◽  
Virus Production ◽  
Virus Infectivity ◽  
Negative Effects ◽  
Algal Viruses ◽  
Host Virus Interactions ◽  
Virus Interactions ◽  
The Impact ◽  
Uv C

Polar seas are under threat of enhanced UV-radiation as well as increasing shipping activities. Considering the ecological importance of marine viruses, it is timely to study the impact of UV-AB on Arctic phytoplankton host–virus interactions and also test the efficacy of ballast water (BW) UV-C treatment on virus infectivity. This study examined the effects of: (i) ecologically relevant doses of UV-AB radiation on Micromonas polaris RCC2258 and its virus MpoV-45T, and (ii) UV-C radiation (doses 25–800 mJ cm−2) on MpoV-45T and other temperate algal viruses. Total UV-AB exposure was 6, 12, 28 and 48 h (during the light periods, over 72 h total). Strongest reduction in algal growth and photosynthetic efficiency occurred for 28 and 48 h UV-AB treatments, and consequently the virus production rates and burst sizes were reduced by more than half (compared with PAR-only controls). For the shorter UV-AB exposed cultures, negative effects by UV (especially Fv/Fm) were overcome without impacting virus proliferation. To obtain the BW desired log−4 reduction in virus infectivity, a UV-C dose of at least 400 mJ cm−2 was needed for MpoV-45T and the temperate algal viruses. This is higher than the commonly used dose of 300 mJ cm−2 in BW treatment.

scholarly journals Killer Archaea: Virus-Mediated Antagonism to CRISPR-Immune Populations Results in Emergent Virus-Host Mutualism

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Samantha J. DeWerff ◽  
Maria A. Bautista ◽  
Matthew Pauly ◽  
Changyi Zhang ◽  
Rachel J. Whitaker
Keyword(s):  
Vertical Transmission ◽  
Natural Populations ◽  
Model Systems ◽  
Microbial Populations ◽  
Escape Mutation ◽  
Content Type ◽  
Sulfolobus Islandicus ◽  
Host Ecology ◽  
Host Virus Interactions ◽  
Virus Interactions

ABSTRACT Theory, simulation, and experimental evolution demonstrate that diversified CRISPR-Cas immunity to lytic viruses can lead to stochastic virus extinction due to a limited number of susceptible hosts available to each potential new protospacer escape mutation. Under such conditions, theory predicts that to evade extinction, viruses evolve toward decreased virulence and promote vertical transmission and persistence in infected hosts. To better understand the evolution of host-virus interactions in microbial populations with active CRISPR-Cas immunity, we studied the interaction between CRISPR-immune Sulfolobus islandicus cells and immune-deficient strains that are infected by the chronic virus SSV9. We demonstrate that Sulfolobus islandicus cells infected with SSV9, and with other related SSVs, kill uninfected, immune strains through an antagonistic mechanism that is a protein and is independent of infectious virus. Cells that are infected with SSV9 are protected from killing and persist in the population. We hypothesize that this infection acts as a form of mutualism between the host and the virus by removing competitors in the population and ensuring continued vertical transmission of the virus within populations with diversified CRISPR-Cas immunity. IMPORTANCE Multiple studies, especially those focusing on the role of lytic viruses in key model systems, have shown the importance of viruses in shaping microbial populations. However, it has become increasingly clear that viruses with a long host-virus interaction, such as those with a chronic lifestyle, can be important drivers of evolution and have large impacts on host ecology. In this work, we describe one such interaction with the acidic crenarchaeon Sulfolobus islandicus and its chronic virus Sulfolobus spindle-shaped virus 9. Our work expands the view in which this symbiosis between host and virus evolved, describing a killing phenotype which we hypothesize has evolved in part due to the high prevalence and diversity of CRISPR-Cas immunity seen in natural populations. We explore the implications of this phenotype in population dynamics and host ecology, as well as the implications of mutualism between this virus-host pair.

scholarly journals Pathways and microRNAs bioinformatics analyses identifying possible existing therapeutics for COVID-19 treatment

2020 ◽  
Author(s):  
Laura Teodori ◽  
Piero Sestili ◽  
Valeria Madiai ◽  
Sofia Coppari ◽  
Daniele Fraternale ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
In Silico ◽  
Molecular Mechanisms ◽  
Hdac Inhibitors ◽  
Converting Enzyme ◽  
Bioinformatics Analyses ◽  
Off Label ◽  
Host Virus Interactions ◽  
Virus Interactions ◽  
Ranked List

Abstract Over 180.000 SARS-COV-2 positive cases have been confirmed in Italy as April 20, with the number of deaths exceeding 23 thousand, making Italy the second Country for world COVID-19 deaths. Such enormous occurrence of infected and dead people raises the urgent demand of effective fast available treatments to control and diminish this pandemic. Discovering the cellular/molecular mechanisms of SARS-COV-2 pathogenicity is of paramount importance to understand how the infection becomes a disease and for therapeutically approaching it. From literature data, through a bioinformatics approach, an in silico analysis was performed, to predict the putative virus targets and evidence the already available therapeutics. Literature experimental results identified angiotensin-converting enzyme ACE and Spike proteins particularly involved in COVID-19. We thus investigate on the signaling pathways modulated by the two proteins through query miRNet, the platform linking miRNAs, targets and functions. We predicted microRNAs (miRs), miR-335-5p and miR-26b-5p, as being modulated by Spike and ACE together with deacetylate histones pathway HDAC. Our results matched with the available clinical data. We hypothesize the current and EMA-approved, SARS-COV-2 off-label, HDAC inhibitors (HDACis) drugs may be repurposed to limit or block host-virus interactions. A ranked list of compounds is given that can be tested.

scholarly journals Baculovirus utilizes cholesterol transporter Niemann–Pick C1 for host cell entry

2018 ◽  
Author(s):  
Zhihong Li ◽  
Junhong Wei ◽  
Youpeng Fan ◽  
Xionge Mei ◽  
Qiang He ◽  
...  
Keyword(s):  
Bombyx Mori ◽  
Molecular Mechanisms ◽  
Insect Cells ◽  
Foreign Gene ◽  
Virus Infectivity ◽  
Viral Glycoprotein ◽  
Enveloped Viruses ◽  
Baculovirus Infection ◽  
Niemann Pick

ABSTRACTThe dual roles of baculovirus for the control of natural insect populations as an insecticide, and for foreign gene expression and delivery, have called for a comprehensive understanding of the molecular mechanisms governing viral infection. Here, we demonstrate that theBombyx moriNiemann-Pick C1 (BmNPC1) is essential for baculovirus infection in insect cells. Both pretreatment ofBombyx moriembryonic cells (BmE) with NPC1 antagonists (imipramine or U18666A) and down-regulation of NPC1 expression resulted in a significant reduction in baculovirus BmNPV (Bombyx morinuclear polyhedrosis virus) infectivity. Furthermore, we show that the major glycoprotein gp64 of BmNPV, responsible for both receptor binding and fusion, is able to interact predominantly with the BmNPC1 C domain, with an enhanced binding capacity at low pH conditions, indicating that NPC1 most likely plays a role during viral fusion in endosomal compartments. Our results, combined with previous studies identifying an essential role of hNPC1 in filovirus infection, suggest that the glycoprotein of several enveloped viruses possess a shared strategy of exploiting host NPC1 proteins during virus intracellular entry events.IMPORTANCEBmNPV is one of the most important members of theBaculoviridae; many viruses in this family have been frequently employed as viral vectors for foreign gene delivery or expression and as biopesticides, but their host receptors still remain unclear. Here, we describe that the intracellular cholesterol transporter BmNPC1 is indispensable for BmNPV infection in insect cells, and it interacts with the major viral glycoprotein gp64. Our study on the role of BmNPC1 in baculovirus infection has further expanded the list of the enveloped viruses that require host NPC1 proteins for entry, and will ultimately help us to uncover the molecular mechanism of the involvement of NPC1 proteins in the entry process of many enveloped viruses.

scholarly journals Tobacco curly shoot virus Down-Regulated the Expression of nbe-miR167b-3p to Facilitate Its Infection in Nicotiana benthamiana

2021 ◽  
Vol 12 ◽  
Author(s):  
Rui Wu ◽  
Gentu Wu ◽  
Lyuxin Wang ◽  
Xu Wang ◽  
Zhuoying Liu ◽  
...  
Keyword(s):  
Nicotiana Benthamiana ◽  
Target Gene ◽  
Molecular Mechanisms ◽  
Leaf Curling ◽  
The Family ◽  
Tobacco Curly Shoot Virus ◽  
Host Virus Interactions ◽  
Virus Interactions ◽  
The Relationship ◽  
Short Tandem

Tobacco curly shoot virus (TbCSV) belongs to the genus Begomovirus of the family Geminiviridae, and causes leaf curling and curly shoot symptoms in tobacco and tomato crops. MicroRNAs (miRNAs) are pivotal modulators of plant development and host-virus interactions. However, the relationship between TbCSV infection and miRNAs accumulation has not been well investigated. The present study was conducted to analyze different expressions of miRNAs in Nicotiana benthamiana in response to the infection of TbCSV via small RNAs sequencing. The results showed that 15 up-regulated miRNAs and 12 down-regulated miRNAs were differentially expressed in TbCSV infected N. benthamiana, and nbe-miR167b-3p was down-regulated. To decipher the relationship between nbe-miR167b-3p expression and the accumulations of TbCSV DNA, pCVA mediation of miRNA overexpression and PVX based short tandem target mimic (STTM) were used in this study. It was found that overexpression of nbe-miR167b-3p attenuated leaf curling symptom of TbCSV and decreased viral DNA accumulation, but suppression of nbe-miR167b-3p expression enhanced the symptoms and accumulation of TbCSV. PRCP, the target gene of nbe-miR167b-3p, was silenced in plants using VIGS and this weakened the viral symptoms and DNA accumulation of TbCSV in the plants. Overall, this study clarified the effect of nbe-miR167b-3p on plant defense during TbCSV infection, and provided a framework to reveal the molecular mechanisms of miRNAs between plants and viruses.

scholarly journals Trapping the Enemy: Vermamoeba vermiformis Circumvents Faustovirus Mariensis Dissemination by Enclosing Viral Progeny inside Cysts

2019 ◽  
Vol 93 (14) ◽  
Author(s):  
Iara Borges ◽  
Rodrigo Araújo Lima Rodrigues ◽  
Fábio Pio Dornas ◽  
Gabriel Almeida ◽  
Isabella Aquino ◽  
...  
Keyword(s):  
Point Of View ◽  
Free Living ◽  
Content Type ◽  
Vermamoeba Vermiformis ◽  
Evolution Of Life ◽  
Free Living Amoeba ◽  
Infected Cells ◽  
Giant Viruses ◽  
Host Virus Interactions ◽  
Virus Interactions

ABSTRACT Viruses depend on cells to replicate and can cause considerable damage to their hosts. However, hosts have developed a plethora of antiviral mechanisms to counterattack or prevent viral replication and to maintain homeostasis. Advantageous features are constantly being selected, affecting host-virus interactions and constituting a harsh race for supremacy in nature. Here, we describe a new antiviral mechanism unveiled by the interaction between a giant virus and its amoebal host. Faustovirus mariensis infects Vermamoeba vermiformis, a free-living amoeba, and induces cell lysis to disseminate into the environment. Once infected, the cells release a soluble factor that triggers the encystment of neighbor cells, preventing their infection. Remarkably, infected cells stimulated by the factor encyst and trap the viruses and viral factories inside cyst walls, which are no longer viable and cannot excyst. This unprecedented mechanism illustrates that a plethora of antiviral strategies remains to be discovered in nature. IMPORTANCE Understanding how viruses of microbes interact with its hosts is not only important from a basic scientific point of view but also for a better comprehension of the evolution of life. Studies involving large and giant viruses have revealed original and outstanding mechanisms concerning virus-host relationships. Here, we report a mechanism developed by Vermamoeba vermiformis, a free-living amoeba, to reduce Faustovirus mariensis dissemination. Once infected, V. vermiformis cells release a factor that induces the encystment of neighbor cells, preventing infection of further cells and/or trapping the viruses and viral factories inside the cyst walls. This phenomenon reinforces the need for more studies regarding large/giant viruses and their hosts.

scholarly journals Activation of the Chicken Type I Interferon Response by Infectious Bronchitis Coronavirus

2014 ◽  
Vol 89 (2) ◽  
pp. 1156-1167 ◽  
Author(s):  
Joeri Kint ◽  
Marcela Fernandez-Gutierrez ◽  
Helena J. Maier ◽  
Paul Britton ◽  
Martijn A. Langereis ◽  
...  
Keyword(s):  
Type I Interferon ◽  
Cell Types ◽  
Interferon Response ◽  
Type I ◽  
Content Type ◽  
Infectious Bronchitis ◽  
Tracheal Epithelial Cells ◽  
Chicken Cell ◽  
Host Virus Interactions ◽  
Virus Interactions

ABSTRACTCoronaviruses from both theAlphacoronavirusandBetacoronavirusgenera interfere with the type I interferon (IFN) response in various ways, ensuring the limited activation of the IFN response in most cell types. Of the gammacoronaviruses that mainly infect birds, little is known about the activation of the host immune response. We show that the prototypicalGammacoronavirus, infectious bronchitis virus (IBV), induces a delayed activation of the IFN response in primary renal cells, tracheal epithelial cells, and a chicken cell line. In fact,Ifnβexpression is delayed with respect to the peak of viral replication and the accompanying accumulation of double-stranded RNA (dsRNA). In addition, we demonstrate that MDA5 is the primary sensor forGammacoronavirusinfections in chicken cells. Furthermore, we provide evidence that accessory proteins 3a and 3b of IBV modulate the response at the transcriptional and translational levels. Finally, we show that, despite the lack of activation of the IFN response during the early phase of IBV infection, the signaling of nonself dsRNA through both MDA5 and TLR3 remains intact in IBV-infected cells. Taken together, this study provides the first comprehensive analysis of host-virus interactions of aGammacoronaviruswith avian innate immune responses.IMPORTANCEOur results demonstrate that IBV has evolved multiple strategies to avoid the activation of the type I interferon response. Taken together, the present study closes a gap in the understanding of host-IBV interaction and paves the way for further characterization of the mechanisms underlying immune evasion strategies as well as the pathogenesis of gammacoronaviruses.

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