scholarly journals A Host Susceptibility Gene, DR1, Facilitates Influenza A Virus Replication by Suppressing Host Innate Immunity and Enhancing Viral RNA Replication

2015 ◽  
Vol 89 (7) ◽  
pp. 3671-3682 ◽  
Author(s):  
Shih-Feng Hsu ◽  
Wen-Chi Su ◽  
King-Song Jeng ◽  
Michael M. C. Lai
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Susceptibility Gene ◽  
Influenza Virus Infection ◽  
Rna Replication ◽  
Viral Rna ◽  
Host Susceptibility ◽  
Viral Rdrp ◽  
Genome Wide ◽  
A Genome

ABSTRACTInfluenza A virus (IAV) depends on cellular factors to complete its replication cycle; thus, investigation of the factors utilized by IAV may facilitate antiviral drug development. To this end, a cellular transcriptional repressor, DR1, was identified from a genome-wide RNA interference (RNAi) screen. Knockdown (KD) of DR1 resulted in reductions of viral RNA and protein production, demonstrating that DR1 acts as a positive host factor in IAV replication. Genome-wide transcriptomic analysis showed that there was a strong induction of interferon-stimulated gene (ISG) expression after prolonged DR1 KD. We found that beta interferon (IFN-β) was induced by DR1 KD, thereby activating the JAK-STAT pathway to turn on ISG expression, which led to a strong inhibition of IAV replication. This result suggests that DR1 in normal cells suppresses IFN induction, probably to prevent undesired cytokine production, but that this suppression may create a milieu that favors IAV replication once cells are infected. Furthermore, biochemical assays of viral RNA replication showed that DR1 KD suppressed viral RNA replication. We also showed that DR1 associated with all three subunits of the viral RNA-dependent RNA polymerase (RdRp) complex, indicating that DR1 may interact with individual components of the viral RdRp complex to enhance viral RNA replication. Thus, DR1 may be considered a novel host susceptibility gene for IAV replication via a dual mechanism, not only suppressing the host defense to indirectly favor IAV replication but also directly facilitating viral RNA replication.IMPORTANCEInvestigations of virus-host interactions involved in influenza A virus (IAV) replication are important for understanding viral pathogenesis and host defenses, which may manipulate influenza virus infection or prevent the emergence of drug resistance caused by a high error rate during viral RNA replication. For this purpose, a cellular transcriptional repressor, DR1, was identified from a genome-wide RNAi screen as a positive regulator in IAV replication. In the current studies, we showed that DR1 suppressed the gene expression of a large set of host innate immunity genes, which indirectly facilitated IAV replication in the event of IAV infection. Besides this scenario, DR1 also directly enhanced the viral RdRp activity, likely through associating with individual components of the viral RdRp complex. Thus, DR1 represents a novel host susceptibility gene for IAV replication via multiple functions, not only suppressing the host defense but also enhancing viral RNA replication. DR1 may be a potential target for drug development against influenza virus infection.

scholarly journals RNA Secondary Structure as a First Step for Rational Design of the Oligonucleotides towards Inhibition of Influenza A Virus Replication

Pathogens ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 925 ◽  
Author(s):  
Marta Szabat ◽  
Dagny Lorent ◽  
Tomasz Czapik ◽  
Maria Tomaszewska ◽  
Elzbieta Kierzek ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Influenza A Virus ◽  
Influenza A ◽  
Rational Design ◽  
Rna Virus ◽  
Viral Rna ◽  
Structure Information ◽  
A Genome ◽  
Function Relationship ◽  
Interfering Rna

Influenza is an important research subject around the world because of its threat to humanity. Influenza A virus (IAV) causes seasonal epidemics and sporadic, but dangerous pandemics. A rapid antigen changes and recombination of the viral RNA genome contribute to the reduced effectiveness of vaccination and anti-influenza drugs. Hence, there is a necessity to develop new antiviral drugs and strategies to limit the influenza spread. IAV is a single-stranded negative sense RNA virus with a genome (viral RNA—vRNA) consisting of eight segments. Segments within influenza virion are assembled into viral ribonucleoprotein (vRNP) complexes that are independent transcription-replication units. Each step in the influenza life cycle is regulated by the RNA and is dependent on its interplay and dynamics. Therefore, viral RNA can be a proper target to design novel therapeutics. Here, we briefly described examples of anti-influenza strategies based on the antisense oligonucleotide (ASO), small interfering RNA (siRNA), microRNA (miRNA) and catalytic nucleic acids. In particular we focused on the vRNA structure-function relationship as well as presented the advantages of using secondary structure information in predicting therapeutic targets and the potential future of this field.

scholarly journals Genome-wide CRISPR screen identifies host dependency factors for influenza A virus infection

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Bo Li ◽  
Sara M. Clohisey ◽  
Bing Shao Chia ◽  
Bo Wang ◽  
Ang Cui ◽  
...  
Keyword(s):  
Virus Infection ◽  
Influenza A Virus ◽  
Influenza A ◽  
Meta Analysis ◽  
Host Factors ◽  
Validation Data ◽  
Genome Wide ◽  
A Genome ◽  
Crispr Screen ◽  
Influenza A Virus Infection

AbstractHost dependency factors that are required for influenza A virus infection may serve as therapeutic targets as the virus is less likely to bypass them under drug-mediated selection pressure. Previous attempts to identify host factors have produced largely divergent results, with few overlapping hits across different studies. Here, we perform a genome-wide CRISPR/Cas9 screen and devise a new approach, meta-analysis by information content (MAIC) to systematically combine our results with prior evidence for influenza host factors. MAIC out-performs other meta-analysis methods when using our CRISPR screen as validation data. We validate the host factors, WDR7, CCDC115 and TMEM199, demonstrating that these genes are essential for viral entry and regulation of V-type ATPase assembly. We also find that CMTR1, a human mRNA cap methyltransferase, is required for efficient viral cap snatching and regulation of a cell autonomous immune response, and provides synergistic protection with the influenza endonuclease inhibitor Xofluza.

scholarly journals CNOT4-Mediated Ubiquitination of Influenza A Virus Nucleoprotein Promotes Viral RNA Replication

mBio ◽  
2017 ◽  
Vol 8 (3) ◽  
Author(s):  
Yu-Chen Lin ◽  
King-Song Jeng ◽  
Michael M. C. Lai
Keyword(s):  
Influenza Virus ◽  
Influenza A Virus ◽  
Ubiquitin Ligase ◽  
Influenza A ◽  
Rna Binding ◽  
Rna Replication ◽  
Viral Rna ◽  
Mass Spectrometry Analysis ◽  
Positive Role

ABSTRACT Influenza A virus (IAV) RNA segments are individually packaged with viral nucleoprotein (NP) and RNA polymerases to form a viral ribonucleoprotein (vRNP) complex. We previously reported that NP is a monoubiquitinated protein which can be deubiquitinated by a cellular ubiquitin protease, USP11. In this study, we identified an E3 ubiquitin ligase, CNOT4 (Ccr4-Not transcription complex subunit 4), which can ubiquitinate NP. We found that the levels of viral RNA, protein, viral particles, and RNA polymerase activity in CNOT4 knockdown cells were lower than those in the control cells upon IAV infection. Conversely, overexpression of CNOT4 rescued viral RNP activity. In addition, CNOT4 interacted with the NP in the cell. An in vitro ubiquitination assay also showed that NP could be ubiquitinated by in vitro -translated CNOT4, but ubiquitination did not affect the protein stability of NP. Significantly, CNOT4 increased NP ubiquitination, whereas USP11 decreased it. Mass spectrometry analysis of ubiquitinated NP revealed multiple ubiquitination sites on the various lysine residues of NP. Three of these, K184, K227, and K273, are located on the RNA-binding groove of NP. Mutations of these sites to arginine reduced viral RNA replication. These results indicate that CNOT4 is a ubiquitin ligase of NP, and ubiquitination of NP plays a positive role in viral RNA replication. IMPORTANCE Influenza virus, particularly influenza A virus, causes severe and frequent outbreaks among human and avian species. Finding potential target sites for antiviral agents is of utmost importance from the public health point of view. We previously found that viral nucleoprotein (NP) is ubiquitinated, and ubiquitination enhances viral RNA replication. In this study, we found a cellular ubiquitin ligase, CNOT4, capable of ubiquitinating NP. The ubiquitination sites are scattered on the surface of the NP molecule, which is critical for RNA replication. CNOT4 and a ubiquitin protease, USP11, together regulate the extent of NP ubiquitination and thereby the efficiency of RNA replication. This study thus identifies a potential antiviral target site and reveals a novel posttranslational mechanism for regulating viral replication. This represents a novel finding in the literature of influenza virus research.

scholarly journals TNK2/ACK1 Strengthen Influenza A Virus Infection by Blocking Viral Matrix 2 Protein(M2) into Lysosome to Degradation

2021 ◽  
Author(s):  
Ao Zhou ◽  
Xia Dong ◽  
Bin Tang
Keyword(s):  
Influenza Virus ◽  
Virus Infection ◽  
Influenza A Virus ◽  
Protein Trafficking ◽  
Influenza A ◽  
Influenza Virus Infection ◽  
Wild Type ◽  
Genome Wide ◽  
Mutant Cells

Abstract BackgroundTNK2/ACK1, a non-receptor tyrosine kinase, plays critical roles in signalling transduces and trafficking. Our previous genome-wide CRISPR/CAS9 knockout screen revealed that mutant of TNK2 produced more restrict to influenza virus infection. In this study, we aim to illustrate the role of TNK2 for influenza A virus (IAV) replication in human cells.ResultsCRISPR/Cas9-mediated mutant of TNK2 resulted in a significant reduction in viral proteins expression and viral titres for multiple influenza strains, and furthermore, a decrease of nuclear import of IAV in the infected TNK2 mutant cells was observed in 3h post-infection. Interestingly, TNK2 mutation enhanced the colocalization of LC3 with autophagic receptor p62 and led to the attenuation of influenza virus-caused accumulation of autophagosomes in TNK2 mutant cells. Further, confocal microscopy visualization result showed that influenza viral matrix 2 (M2) was colocalized with Lamp1 in the infected TNK2 mutant cells in early infection, while almost no colocalization between M2 and Lamp1 was observed in IAV-infected wild-type cells. Moreover, TNK2 depletion also affected the trafficking of early endosome and the movement of influenza viral NP and M2.ConclusionsOur results identified TNK2 as a critical host factor for influenza viral M2 protein trafficking, suggesting that TNK2 will be an attractive target for the development of antivirals therapeutics.

scholarly journals Nonconserved Nucleotides at the 3′ and 5′ Ends of an Influenza A Virus RNA Play an Important Role in Viral RNA Replication

Virology ◽  
1996 ◽  
Vol 217 (1) ◽  
pp. 242-251 ◽  
Author(s):  
HONGYONG ZHENG ◽  
PETER PALESE ◽  
ADOLFO GARCÍA-SASTRE
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Rna Replication ◽  
Viral Rna ◽  
Virus Rna

scholarly journals Interaction of the Influenza A Virus Nucleocapsid Protein with the Viral RNA Polymerase Potentiates Unprimed Viral RNA Replication

2008 ◽  
Vol 83 (1) ◽  
pp. 29-36 ◽  
Author(s):  
Laura L. Newcomb ◽  
Rei-Lin Kuo ◽  
Qiaozhen Ye ◽  
Yunyun Jiang ◽  
Yizhi Jane Tao ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Nucleocapsid Protein ◽  
Influenza A ◽  
Rna Binding ◽  
Direct Interaction ◽  
Rna Replication ◽  
Binding Activity ◽  
Viral Rna ◽  
Viral Polymerase

ABSTRACT The influenza A virus polymerase transcribes and replicates the eight virion RNA (vRNA) segments. Transcription is initiated with capped RNA primers excised from cellular pre-mRNAs by the intrinsic endonuclease of the viral polymerase. Viral RNA replication occurs in two steps: first a full-length copy of vRNA is made, termed cRNA, and then this cRNA is copied to produce vRNA. The synthesis of cRNAs and vRNAs is initiated without a primer, in contrast to the initiation of viral mRNA synthesis, and requires the viral nucleocapsid protein (NP). The mechanism of unprimed viral RNA replication is poorly understood. To elucidate this mechanism, we used purified recombinant influenza virus polymerase complexes and NP to establish an in vitro system that catalyzes the unprimed synthesis of cRNA and vRNA using 50-nucleotide-long RNA templates. The purified viral polymerase and NP are sufficient for catalyzing this RNA synthesis without a primer, suggesting that host cell factors are not required. We used this purified in vitro replication system to demonstrate that the RNA-binding activity of NP is not required for the unprimed synthesis of cRNA and vRNA. This result rules out two models that postulate that the RNA-binding activity of NP mediates the switch from capped RNA-primed transcription to unprimed viral RNA replication. Because we showed that NP lacking RNA-binding activity binds directly to the viral polymerase, it is likely that a direct interaction between NP and the viral polymerase results in a modification of the polymerase in favor of unprimed initiation.

Viral RNA Polymerase: A Promising Antiviral Target for Influenza A Virus

2013 ◽  
Vol 20 (31) ◽  
pp. 3923-3934 ◽  
Author(s):  
Fangyuan Shi ◽  
Yuanchao Xie ◽  
Lifang Shi ◽  
Wenfang Xu
Keyword(s):  
Rna Polymerase ◽  
Influenza A Virus ◽  
Influenza A ◽  
Viral Rna

scholarly journals Development of an HTS Assay for the Search of Anti-influenza Agents Targeting the Interaction of Viral RNA with the NS1 Protein

2008 ◽  
Vol 13 (7) ◽  
pp. 581-590 ◽  
Author(s):  
Marta Maroto ◽  
Yolanda Fernandez ◽  
Juan Ortin ◽  
Fernando Pelaez ◽  
M. Angerles Cabello
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Cytopathic Effect ◽  
Nonstructural Protein ◽  
Specific Interaction ◽  
Chemical Compounds ◽  
Viral Rna ◽  
Ns1 Protein ◽  
Rna Molecules ◽  
Novel Target

The NS1 protein is a nonstructural protein encoded by the influenza A virus. It is responsible for many alterations produced in the cellular metabolism upon infection by the virus and for modulation of virus virulence. The NS1 protein is able to perform a large variety of functions due to its ability to bind various types of RNA molecules, from both viral and nonviral origin, and to interact with several cell factors. With the aim of exploring whether the binding of NS1 protein to viral RNA (vRNA) could constitute a novel target for the search of anti-influenza drugs, a filter-binding assay measuring the specific interaction between the recombinant His-NS1 protein from influenza A virus and a radiolabeled model vRNA ( 32P-vNSZ) was adapted to a format suitable for screening and easy automation. Flashplate® technology (PerkinElmer, Waltham, MA), either in 96- or 384-well plates, was used. The Flashplate® wells were precoated with the recombinant His-NS1 protein, and the binding of His-NS1 to a 35S-vNSZ probe was measured. A pilot screening of a collection of 27,520 mixtures of synthetic chemical compounds was run for inhibitors of NS1 binding to vRNA. We found 3 compounds in which the inhibition of NS1 binding to vRNA, observed at submicromolar concentrations, was correlated with a reduction of the cytopathic effect during the infection of cell cultures with influenza virus. These results support the hypothesis that the binding of NS1 to vRNA could be a novel target for the development of anti-influenza drugs. ( Journal of Biomolecular Screening 2008:581-590)

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