scholarly journals Staufen1 Protein Participates Positively in the Viral RNA Replication of Enterovirus 71

Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 142 ◽  
Author(s):  
Young-Mao Chen ◽  
Bo-Ting Ou ◽  
Chao-Ying Chen ◽  
Han-Hsiang Chan ◽  
Chih-Jung Chen ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Virus ◽  
Rna Stability ◽  
Enterovirus 71 ◽  
Viral Rna ◽  
Viral Translation ◽  
Rna Translation ◽  
Rna Accumulation

The double-stranded RNA-binding protein Staufen1 (Stau1) has multiple functions during RNA virus infection. In this study, we investigated the role of Stau1 in viral translation by using a combination of enterovirus 71 (EV-A71) infection, RNA reporter transfection, and in vitro functional and biochemical assays. We demonstrated that Stau1 specifically binds to the 5′-untranslated region of EV-A71 viral RNA. The RNA-binding domain 2-3 of Stau1 is responsible for this binding ability. Subsequently, we created a Stau1 knockout cell line using the CRISPR/Cas9 approach to further characterize the functional role of Stau1’s interaction with viral RNA in the EV-A71-infected cells. Both the viral RNA accumulation and viral protein expression were downregulated in the Stau1 knockout cells compared with the wild-type naïve cells. Moreover, dysregulation of viral RNA translation was observed in the Stau1 knockout cells using ribosome fractionation assay, and a reduced RNA stability of 5′-UTR of the EV-A71 was also identified using an RNA stability assay, which indicated that Stau1 has a role in facilitating viral translation during EV-A71 infection. In conclusion, we determined the functional relevance of Stau1 in the EV-A71 infection cycle and herein describe the mechanism of Stau1 participation in viral RNA translation through its interaction with viral RNA. Our results suggest that Stau1 is an important host factor involved in viral translation and influential early in the EV-A71 replication cycle.

scholarly journals Novel Antiviral Agent DTriP-22 Targets RNA-Dependent RNA Polymerase of Enterovirus 71

2009 ◽  
Vol 53 (7) ◽  
pp. 2740-2747 ◽  
Author(s):  
Tzu-Chun Chen ◽  
Hwan-You Chang ◽  
Pei-Fen Lin ◽  
Jyh-Haur Chern ◽  
John Tsu-An Hsu ◽  
...  
Keyword(s):  
Potent Inhibitor ◽  
Antiviral Agents ◽  
Enterovirus 71 ◽  
Antiviral Agent ◽  
Viral Rna ◽  
Drug Resistant ◽  
Rna Dependent Rna Polymerase ◽  
Rna Accumulation ◽  
Elongation Activity

ABSTRACT Enterovirus 71 (EV71) has emerged as an important virulent neurotropic enterovirus in young children. DTriP-22 (4{4-[(2-bromo-phenyl)-(3-methyl-thiophen-2-yl)-methyl]-piperazin-1-yl}-1-pheny-1H-pyrazolo[3,4-d]pyrimidine) was found to be a novel and potent inhibitor of EV71. The molecular target of this compound was identified by analyzing DTriP-22-resistant viruses. A substitution of lysine for Arg163 in EV71 3D polymerase rendered the virus drug resistant. DTriP-22 exhibited the ability to inhibit viral replication by reducing viral RNA accumulation. The compound suppressed the accumulated levels of both positive- and negative-stranded viral RNA during virus infection. An in vitro polymerase assay indicated that DTriP-22 inhibited the poly(U) elongation activity, but not the VPg uridylylation activity, of EV71 polymerase. These findings demonstrate that the nonnucleoside analogue DTriP-22 acts as a novel inhibitor of EV71 polymerase. DTriP-22 also exhibited a broad spectrum of antiviral activity against other picornaviruses, which highlights its potential in the development of antiviral agents.

scholarly journals Role of an Internal and Two 3′-Terminal RNA Elements in Assembly of Tombusvirus Replicase

2005 ◽  
Vol 79 (16) ◽  
pp. 10608-10618 ◽  
Author(s):  
Zivile Panaviene ◽  
Tadas Panavas ◽  
Peter D. Nagy
Keyword(s):  
Rna Virus ◽  
Viral Rna ◽  
Host Cells ◽  
Replication Proteins ◽  
Rna Sequences ◽  
Alternative Structures ◽  
Recognition Element ◽  
Rna Elements

ABSTRACT Plus-strand RNA virus replication requires the assembly of the viral replicase complexes on intracellular membranes in the host cells. The replicase of Cucumber necrosis virus (CNV), a tombusvirus, contains the viral p33 and p92 replication proteins and possible host factors. In addition, the assembly of CNV replicase is stimulated in the presence of plus-stranded viral RNA (Z. Panaviene et al., J. Virol. 78:8254-8263, 2004). To define cis-acting viral RNA sequences that stimulate replicase assembly, we performed a systematic deletion approach with a model tombusvirus replicon RNA in Saccharomyces cerevisiae, which also coexpressed p33 and p92 replication proteins. In vitro replicase assays performed with purified CNV replicase preparations from yeast revealed critical roles for three RNA elements in CNV replicase assembly: the internal p33 recognition element (p33RE), the replication silencer element (RSE), and the 3′-terminal minus-strand initiation promoter (gPR). Deletion or mutagenesis of these elements reduced the activity of the CNV replicase to a minimal level. In addition to the primary sequences of gPR, RSE, and p33RE, formation of two alternative structures among these elements may also play a role in replicase assembly. Altogether, the role of multiple RNA elements in tombusvirus replicase assembly could be an important factor to ensure fidelity of template selection during replication.

scholarly journals Computational Mapping of the Human-SARS-CoV-2 Protein-RNA Interactome

2021 ◽  
Author(s):  
Marc Horlacher ◽  
Svitlana Oleshko ◽  
Yue Hu ◽  
Mahsa Ghanbari ◽  
Ernesto Elorduy Vergara ◽  
...  
Keyword(s):  
Deep Learning ◽  
Viral Replication ◽  
Binding Sites ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Stability ◽  
Experimental Studies ◽  
Viral Rna ◽  
Virus Binding

It is well known that viruses make extensive use of the host cell's machinery, hijacking it for the purpose of viral replication and interfere with the activity of master regulatory proteins - including RNA binding proteins (RBPs). RBPs recognize and bind RNA molecules to control several steps of cellular RNA metabolism, such as splicing, transcript stability, translation and others, and recognize their targets by means of sequence or structure motifs. Host RBPs are critical factors for viral replication, especially for RNA viruses, and have been shown to influence viral RNA stability, replication and escape of host immune response. While current research efforts have been centered around identifying mechanisms of host cell-entry, the role of host RBPs in the context of SARS-CoV-2 replication remains poorly understood. Few experimental studies have started mapping the SARS-CoV-2 RNA-protein interactome in infected human cells, but they are limited in the resolution and exhaustivity of their output. On the other hand, computational approaches enable screening of large numbers of human RBPs for putative interactions with the viral RNA, and are thus crucial to prioritize candidates for further experimental investigation. Here, we investigate the role of RBPs in the context of SARS-CoV-2 by constructing a first single-nucleotide \textit{in silico} map of human RBP / viral RNA interactions by using deep learning models trained on RNA sequences. Our framework is based on Pysster and DeepRiPe, two deep learning method which use a convolutional neural network to learn sequence-structure preferences of a specific RBP. Models were trained using eCLIP and PAR-CLIP datasets for >150 RBP generated on human cell lines and applied cross-species to predict the propensity of each RBP to bind the SARS-CoV-2 genome. After extensive validation of predicted binding sites, we generate RBP binding profiles across different SARS-CoV-2 variants and 6 other betacoronaviruses. We address the questions of (1) conservation of binding between pathogenic betacoronaviruses, (2) differential binding across viral strains and (3) gain and loss of binding events in novel mutants which can be linked to disease severity and spread in the population. In addition, we explore the specific pathways hijacked by the virus, by integrating host factors linked to these virus-binding RBPs through protein-protein interaction networks or genome wide CRISPR screening. We believe that identifying viral RBP binding sites will give valuable insights into the mechanisms of host-virus interaction, thus giving us a deeper understanding of the life cycle of SARS-CoV-2 but also opening new avenues for the development of new therapeutics.

scholarly journals The Proteasomal Rpn11 Metalloprotease Suppresses Tombusvirus RNA Recombination and Promotes Viral Replication via Facilitating Assembly of the Viral Replicase Complex

2014 ◽  
Vol 89 (5) ◽  
pp. 2750-2763 ◽  
Author(s):  
K. Reddisiva Prasanth ◽  
Daniel Barajas ◽  
Peter D. Nagy
Keyword(s):  
Viral Replication ◽  
Genetic Recombination ◽  
Rna Virus ◽  
Viral Rna ◽  
Rna Recombination ◽  
Viral Recombination ◽  
Antiviral Responses ◽  
New Hosts

ABSTRACTRNA viruses co-opt a large number of cellular proteins that affect virus replication and, in some cases, viral genetic recombination. RNA recombination helps viruses in an evolutionary arms race with the host's antiviral responses and adaptation of viruses to new hosts. Tombusviruses and a yeast model host are used to identify cellular factors affecting RNA virus replication and RNA recombination. In this study, we have examined the role of the conserved Rpn11p metalloprotease subunit of the proteasome, which couples deubiquitination and degradation of proteasome substrates, in tombusvirus replication and recombination inSaccharomyces cerevisiaeand plants. Depletion or mutations of Rpn11p lead to the rapid formation of viral RNA recombinants in combination with reduced levels of viral RNA replication in yeast orin vitrobased on cell extracts. Rpn11p interacts with the viral replication proteins and is recruited to the viral replicase complex (VRC). Analysis of the multifunctional Rpn11p has revealed that the primary role of Rpn11p is to act as a “matchmaker” that brings the viral p92polreplication protein and the DDX3-like Ded1p/RH20 DEAD box helicases into VRCs. Overexpression of Ded1p can complement the defect observed inrpn11mutant yeast by reducing TBSV recombination. This suggests that Rpn11p can suppress tombusvirus recombination via facilitating the recruitment of the cellular Ded1p helicase, which is a strong suppressor of viral recombination, into VRCs. Overall, this work demonstrates that the co-opted Rpn11p, which is involved in the assembly of the functional proteasome, also functions in the proper assembly of the tombusvirus VRCs.IMPORTANCERNA viruses evolve rapidly due to genetic changes based on mutations and RNA recombination. Viral genetic recombination helps viruses in an evolutionary arms race with the host's antiviral responses and facilitates adaptation of viruses to new hosts. Cellular factors affect viral RNA recombination, although the role of the host in virus evolution is still understudied. In this study, we used a plant RNA virus, tombusvirus, to examine the role of a cellular proteasomal protein, called Rpn11, in tombusvirus recombination in a yeast model host, in plants, andin vitro. We found that the cellular Rpn11 is subverted for tombusvirus replication and Rpn11 has a proteasome-independent function in facilitating viral replication. When the Rpn11 level is knocked down or a mutated Rpn11 is expressed, then tombusvirus RNA goes through rapid viral recombination and evolution. Taken together, the results show that the co-opted cellular Rpn11 is a critical host factor for tombusviruses by regulating viral replication and genetic recombination.

scholarly journals Proteomics Analysis of the Tombusvirus Replicase: Hsp70 Molecular Chaperone Is Associated with the Replicase and Enhances Viral RNA Replication

2006 ◽  
Vol 80 (5) ◽  
pp. 2162-2169 ◽  
Author(s):  
Saulius Serva ◽  
Peter D. Nagy
Keyword(s):  
Rna Binding ◽  
Rna Virus ◽  
Rna Replication ◽  
Viral Rna ◽  
Mass Spectrometry Analysis ◽  
Host Proteins ◽  
Two Dimensional Gel Electrophoresis ◽  
Viral Replicase

ABSTRACT Plus-strand RNA virus replication occurs via the assembly of viral replicase complexes involving multiple viral and host proteins. To identify host proteins present in the cucumber necrosis tombusvirus (CNV) replicase, we affinity purified functional viral replicase complexes from yeast. Mass spectrometry analysis of proteins resolved by two-dimensional gel electrophoresis revealed the presence of CNV p33 and p92 replicase proteins as well as four major host proteins in the CNV replicase. The host proteins included the Ssa1/2p molecular chaperones (yeast homologues of Hsp70 proteins), Tdh2/3p (glyceraldehyde-3-phosphate dehydrogenase, an RNA-binding protein), Pdc1p (pyruvate decarboxylase), and an unknown ∼35-kDa acidic protein. Copurification experiments demonstrated that Ssa1p bound to p33 replication protein in vivo, and surface plasmon resonance measurements with purified recombinant proteins confirmed this interaction in vitro. The double mutant strain (ssa1 ssa2) showed 75% reduction in viral RNA accumulation, whereas overexpression of either Ssa1p or Ssa2p stimulated viral RNA replication by approximately threefold. The activity of the purified CNV replicase correlated with viral RNA replication in the above-mentioned ssa1 ssa2 mutant and in the Ssa overexpression strains, suggesting that Ssa1/2p likely plays an important role in the assembly of the CNV replicase.

scholarly journals Oncogenic lncRNA ZNF561-AS1 is essential for colorectal cancer proliferation and survival through regulation of miR-26a-3p/miR-128-5p-SRSF6 axis

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Zizhen Si ◽  
Lei Yu ◽  
Haoyu Jing ◽  
Lun Wu ◽  
Xidi Wang
Keyword(s):  
Colorectal Cancer ◽  
Rna Binding ◽  
Xenograft Model ◽  
Luciferase Reporter ◽  
Cancer Proliferation ◽  
Mouse Xenograft ◽  
Mouse Xenograft Model

Abstract Background Long non-coding RNAs (lncRNA) are reported to influence colorectal cancer (CRC) progression. Currently, the functions of the lncRNA ZNF561 antisense RNA 1 (ZNF561-AS1) in CRC are unknown. Methods ZNF561-AS1 and SRSF6 expression in CRC patient samples and CRC cell lines was evaluated through TCGA database analysis, western blot along with real-time PCR. SRSF6 expression in CRC cells was also examined upon ZNF561-AS1 depletion or overexpression. Interaction between miR-26a-3p, miR-128-5p, ZNF561-AS1, and SRSF6 was examined by dual luciferase reporter assay, as well as RNA binding protein immunoprecipitation (RIP) assay. Small interfering RNA (siRNA) mediated knockdown experiments were performed to assess the role of ZNF561-AS1 and SRSF6 in the proliferative actives and apoptosis rate of CRC cells. A mouse xenograft model was employed to assess tumor growth upon ZNF561-AS1 knockdown and SRSF6 rescue. Results We find that ZNF561-AS1 and SRSF6 were upregulated in CRC patient tissues. ZNF561-AS1 expression was reduced in tissues from treated CRC patients but upregulated in CRC tissues from relapsed patients. SRSF6 expression was suppressed and enhanced by ZNF561-AS1 depletion and overexpression, respectively. Mechanistically, ZNF561-AS1 regulated SRSF6 expression by sponging miR-26a-3p and miR-128-5p. ZNF561-AS1-miR-26a-3p/miR-128-5p-SRSF6 axis was required for CRC proliferation and survival. ZNF561-AS1 knockdown suppressed CRC cell proliferation and triggered apoptosis. ZNF561-AS1 depletion suppressed the growth of tumors in a model of a nude mouse xenograft. Similar observations were made upon SRSF6 depletion. SRSF6 overexpression reversed the inhibitory activities of ZNF561-AS1 in vivo, as well as in vitro. Conclusion In summary, we find that ZNF561-AS1 promotes CRC progression via the miR-26a-3p/miR-128-5p-SRSF6 axis. This study reveals new perspectives into the role of ZNF561-AS1 in CRC.

scholarly journals RNA Helicase A Regulates the Replication of RNA Viruses

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 361
Author(s):  
Rui-Zhu Shi ◽  
Yuan-Qing Pan ◽  
Li Xing
Keyword(s):  
Virus Replication ◽  
Rna Binding ◽  
Rna Viruses ◽  
Rna Helicase ◽  
Rna Helicase A ◽  
Double Stranded Rna ◽  
Binding Domains ◽  
N Terminus

The RNA helicase A (RHA) is a member of DExH-box helicases and characterized by two double-stranded RNA binding domains at the N-terminus. RHA unwinds double-stranded RNA in vitro and is involved in RNA metabolisms in the cell. RHA is also hijacked by a variety of RNA viruses to facilitate virus replication. Herein, this review will provide an overview of the role of RHA in the replication of RNA viruses.

TaffiX® nasal powder spray forms an effective barrier against infectious new variants of SARS-CoV-2 (COVID-19)

2021 ◽  
Author(s):  
Michal Mandelboim ◽  
Ella Mendelson ◽  
Yaron Drori ◽  
Nofar Atari ◽  
Tair Lapidot ◽  
...  
Keyword(s):  
South African ◽  
Rna Virus ◽  
Rna Extraction ◽  
Real Life ◽  
Preclinical Study ◽  
Viral Rna ◽  
Pcr Analysis ◽  
Effective Barrier ◽  
Gel Layer

Abstract Introduction: While vaccination efforts against SARS-CoV-2 around the world are ongoing -, new high-infectious variants of the virus are being detected. The protection of the available vaccines against some of the new variants is weaker, and experts are concerned that newer as yet undescribed variants of this mutated RNA virus will eventually prove stable against the current vaccines. Additional preventive measures will therefore be needed to protect the population until effective vaccinations are widely available.TaffiX® is a personal, anti-viral nasal powder spray comprised of low pH Hypromellose that upon insufflation into the nose creates a thin gel layer covering the nasal mucosa and forming a protective mechanical barrier that prevents viruses from engaging with nasal cells- the main portal of entry for viruses. Taffix is commercially available in many countries across Europe, Asia America and Africa. In a prior preclinical study, TaffiX® was found to be effective against SARS-CoV-2 Hong Kong/VM20001061/2020 in experimental in vitro conditions. A real-life clinical survey demonstrated that TaffiX® nasal spray significantly reduced the SARS-CoV-2 infection rate post mass-gathering event in a highly endemic community.Objective: The current study aimed to test the protective effect of Taffix against new pathogenic, highly infectious SARS-CoV-2 variants in vitro: the “British” B.1.1.7 (hCoV-19/Israel/CVL-46879-ngs/2020) and the “South African” B.1.351 (hCoV-19/Israel/CVL-2557-ngs/2020) variants.Study design: A TaffiX® gel was formed on a nylon filter, using an amount equivalent to a clinical dose of Taffix . Filters were then seeded with SARS-CoV-2 B.1.1.7 (“British”) and B.1.351 (“South African”) variants. After a 10 -minute incubation at room temperature, the bottom of each filter was washed, and the resulting flow-through was collected and seeded into 24 -well plates containing Vero-E6 cells. After 5 days of incubation, a 200 µl sample from each well was taken for viral RNA extraction followed by SARS-CoV 2 RT-PCR analysis.Results: The TaffiX® gel completely blocked SARS-CoV-2 highly infectious variants B.1.1.7 and B.1.351 in vitro, reducing the titer of recoverable infectious virus as well as viral RNA by 100%.Conclusions: Under in vitro conditions, TaffiX® formed an effective protective barrier against SARS-COV-2 variants (British variant and South African Variant). These results are consistent with prior findings demonstrating the in vitro high efficacy of Taffix gel in preventing viruses from reaching cells and infecting them. These results, added to clinical real-life studies performed with Taffix , support its use as an effective barrier against new variants of SARS-CoV-2 in conjunction with other protective measures.

scholarly journals Cotranslational Coat Protein-Mediated Inhibition of Potyviral RNA Translation

2015 ◽  
Vol 89 (8) ◽  
pp. 4237-4248 ◽  
Author(s):  
Jane Besong-Ndika ◽  
Konstantin I. Ivanov ◽  
Anders Hafrèn ◽  
Thierry Michon ◽  
Kristiina Mäkinen
Keyword(s):  
Coat Protein ◽  
Stop Codon ◽  
Rna Virus ◽  
Viral Rna ◽  
Dependent Manner ◽  
Content Type ◽  
Virion Assembly ◽  
Rna Translation ◽  
Intrinsic Capacity

ABSTRACTPotato virus A(PVA) is a single-stranded positive-sense RNA virus and a member of the familyPotyviridae. The PVA coat protein (CP) has an intrinsic capacity to self-assemble into filamentous virus-like particles, but the mechanism responsible for the initiation of viral RNA encapsidationin vivoremains unclear. Apart from virion assembly, PVA CP is also involved in the inhibition of viral RNA translation. In this study, we show that CP inhibits PVA RNA translation in a dose-dependent manner, through a mechanism involving the CP-encoding region. Analysis of this region, however, failed to identify any RNA secondary structure(s) preferentially recognized by CP, suggesting that the inhibition depends on CP-CP rather than CP-RNA interactions. In agreement with this possibility, insertion of an in-frame stop codon upstream of the CP sequence led to a marked decrease in the inhibition of viral RNA translation. Based on these results, we propose a model in which the cotranslational interactions between excess CP accumulating intransand CP translated from viral RNA incisare required to initiate the translational repression. This model suggests a mechanism for how viral RNA can be sequestered from translation and specifically selected for encapsidation at the late stages of viral infection.IMPORTANCEThe main functions of the CP during potyvirus infection are to protect viral RNA from degradation and to transport it locally, systemically, and from host to host. Although virion assembly is a key step in the potyviral infectious cycle, little is known about how it is initiated and how viral RNA is selected for encapsidation. The results presented here suggest that CP-CP rather than CP-RNA interactions are predominantly involved in the sequestration of viral RNA away from translation. We propose that the cotranslational nature of these interactions may represent a mechanism for the selection of viral RNA for encapsidation. A better understanding of the mechanism of virion assembly may lead to development of crops resistant to potyviruses at the level of viral RNA encapsidation, thereby reducing the detrimental effects of potyvirus infections on food production.

scholarly journals RNA binding to human METTL3-METTL14 restricts N6-deoxyadenosine methylation of DNA in vitro

2022 ◽  
Author(s):  
Shan Qi ◽  
Javier Mota ◽  
Siu-Hong Chan ◽  
Johanna Villarreal ◽  
Nan Dai ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Rna Binding ◽  
Methyl Group ◽  
High Affinity ◽  
Methylation Of Dna ◽  
Dna And Rna ◽  
Close Proximity ◽  
Methylation Activity

Methyltransferase like-3 (METTL3) and METTL14 complex transfers a methyl group from S-adenosyl-L-methionine to N6 amino group of adenosine bases in RNA (m6A) and DNA (m6dA). Emerging evidence highlights a role of METTL3-METTL14 in the chromatin context, especially in processes where DNA and RNA are held in close proximity. However, a mechanistic framework about specificity for substrate RNA/DNA and their interrelationship remain unclear. By systematically studying methylation activity and binding affinity to a number of DNA and RNA oligos with different propensities to form inter- or intra-molecular duplexes or single-stranded molecules in vitro, we uncover an inverse relationship for substrate binding and methylation and show that METTL3-METTL14 preferentially catalyzes the formation of m6dA in single-stranded DNA (ssDNA), despite weaker binding affinity to DNA. In contrast, it binds structured RNAs with high affinity, but methylates the target adenosine in RNA (m6A) much less efficiently than it does in ssDNA. We also show that METTL3-METTL14-mediated methylation of DNA is largely restricted by structured RNA elements prevalent in long noncoding and other cellular RNAs.

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