The Influenza Virus RNA-Polymerase and the Host RNA-Polymerase II: RPB4 Is Targeted by a PB2 Domain That Is Involved in Viral Transcription

Morel, Jessica; Sedano, Laura; Lejal, Nathalie; Costa, Bruno Da; Batsché, Éric; Muchardt, Christian; Delmas, Bernard

doi:10.3390/v14030518

Cited by 11 publications

(13 citation statements)

References 40 publications

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“…A second normalisation was performed by dividing the previously obtained results by the Renilla-luciferase-associated luminescence value. To be as stringent as possible, we chose a threshold higher than the usual limit of 3 and set a threshold of NLR equal to 4 in order to discriminate the presence or absence of interaction [ 39 , 40 ]. The choice of this threshold is part of a positive screening approach aimed at reducing the number of proteins targeted for further investigations.…”

Section: Methodsmentioning

confidence: 99%

Host-Specific Interplay between Foot-and-Mouth Disease Virus 3D Polymerase and the Type-I Interferon Pathway

Sarry

Caignard

Dupré

et al. 2023

Viruses

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Foot-and-mouth disease (FMD) is a highly contagious viral disease affecting cloven-hoofed animals. One of the issues related to this disease is the persistence of its causative agent, foot-and-mouth disease virus (FMDV). While the mechanisms of FMDV persistence remain unclear, there are clues that it may be related to protein–protein interactions (PPI) between viral proteins and cellular proteins involved in the interferon (IFN) response. Since FMDV persistence has been described in cattle, sheep and goats but not in swine, we screened PPI involving FMDV proteins and sixteen major type-I IFN pathway proteins from these four species by nanoluciferase-2-hybrid complementation assay, in order to identify new PPI and determine their host specificity. As the results concerning the 3Dpol were the most interesting in view of the limited data concerning its role in immune escape, we decided to focus particularly on this protein. The identified PPI were confirmed by GST pull-down. We identified PPI between 3Dpol and seven IFN pathway proteins, namely, IKKα, IKKε, IRF3, IRF7, NEMO, MDA5 and MAVS. These PPI are conserved among the four studied species, with the exception of the one between 3Dpol and MAVS, which was only found with the swine protein. We also showed, using luciferase reporter assays, that 3Dpol could inhibit the induction phase of the IFN pathway. These results demonstrate, for the first time, a putative role for 3Dpol in FMDV innate immune escape.

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Section: Methodsmentioning

confidence: 99%

Host-Specific Interplay between Foot-and-Mouth Disease Virus 3D Polymerase and the Type-I Interferon Pathway

Sarry

Caignard

Dupré

et al. 2023

Viruses

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“…To favor proper folding of the FluPol subunits and the VHH16, the two luciferase moieties were fused onto their C terminus. For each sample, the specificity of the interaction over background was estimated by calculating a normalized luminescent ratio (NLR, [ 24 ]). Co-expressed FluPol subunits PA, PB1 or PB2 (fused to Luc1) with VHH16 (fused to Luc2) revealed a NLR value of 10 for the PA-VHH16 interaction ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Antiviral activity of intracellular nanobodies targeting the influenza virus RNA-polymerase core

Bessonne,

Morel,

Nevers

et al. 2023

Preprint

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Influenza viruses transcribe and replicate their genome in the nucleus of the infected cells, two functions that are supported by the viral RNA-dependent RNA-polymerase (FluPol). FluPol displays structural flexibility related to distinct functional states, from an inactive form to conformations competent for replication and transcription. FluPol machinery is constituted by a structurally-invariant core comprising the PB1 subunit stabilized with PA and PB2 domains, whereas the PA endonuclease and PB2 C-domains can pack in different configurations around the core. To get insights into the functioning of FluPol, we selected single-domain nanobodies (VHHs) specific of the influenza A FluPol core. When expressed intracellularly, several of them exhibited inhibitory activity on type A FluPol, but not on the type B one. The most potent VHH (VHH16) targets PA, but preferentially bind the PA-PB1 dimer with an affinity below the nanomolar range. Ectopic intracellular expression of VHH16 in virus permissive cells blocks multiplication of different influenza A subtypes, even when induced at late times post-infection. VHH16 was found to impair the transport of the PA-PB1 dimer to the nucleus, without affecting its handling by the importin b RanBP5 and subsequent steps in FluPol assembly. These data suggest that the VHH16 neutralization activity is likely due to an alteration of the import of the PA-PB1 dimer into the nucleus, resulting to an inhibition of FluPol functioning. VHH16 binding site represent a potential target for antiviral development.

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“…Moreover, the PB2 subunit initiates communication with the Pol II RPB4 subunit, which efficiently permits PB2 to be positioned close to the cap structure's departure point. 58 Additionally, the host factor Ribosomal RNA Processing 1 Homolog B (RRP1B) actively engages with PB1, PB2, as well as the host nucleosome. This collaborative interaction effectively enables FluPol to target the host transcriptional machinery precisely.…”

Section: Nuclear Replicating Influenza Virusmentioning

confidence: 99%

Viral RNA capping: Mechanisms and antiviral therapy

Chen,

Jiang,

et al. 2024

Journal of Medical Virology

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RNA capping is an essential trigger for protein translation in eukaryotic cells. Many viruses have evolved various strategies for initiating the translation of viral genes and generating progeny virions in infected cells via synthesizing cap structure or stealing the RNA cap from nascent host messenger ribonucleotide acid (mRNA). In addition to protein translation, a new understanding of the role of the RNA cap in antiviral innate immunity has advanced the field of mRNA synthesis in vitro and therapeutic applications. Recent studies on these viral RNA capping systems have revealed startlingly diverse ways and molecular machinery. A comprehensive understanding of how viruses accomplish the RNA capping in infected cells is pivotal for designing effective broad‐spectrum antiviral therapies. Here we systematically review the contemporary insights into the RNA‐capping mechanisms employed by viruses causing human and animal infectious diseases, while also highlighting its impact on host antiviral innate immune response. The therapeutic applications of targeting RNA capping against viral infections and the development of RNA‐capping inhibitors are also summarized.

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The Influenza Virus RNA-Polymerase and the Host RNA-Polymerase II: RPB4 Is Targeted by a PB2 Domain That Is Involved in Viral Transcription

Cited by 11 publications

References 40 publications

Host-Specific Interplay between Foot-and-Mouth Disease Virus 3D Polymerase and the Type-I Interferon Pathway

Host-Specific Interplay between Foot-and-Mouth Disease Virus 3D Polymerase and the Type-I Interferon Pathway

Antiviral activity of intracellular nanobodies targeting the influenza virus RNA-polymerase core

Viral RNA capping: Mechanisms and antiviral therapy

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