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Viruses
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Function and Structure of Viral Ribonucleoproteins Complexes
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Function and Structure of Viral Ribonucleoproteins Complexes

A special issue of Viruses (ISSN 1999-4915).

Deadline for manuscript submissions: closed (1 August 2020) | Viewed by 63117

Special Issue Editor

Dr. Serena Bernacchi

E-Mail Website
Guest Editor
Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Architecture et Réactivité de l'ARN, CNRS UPR 9002, 2 allée Conrad Roentgen, F-67084 Strasbourg, France
Interests: viral ribonucleoproteins; genome incorporation and assembly

Special Issue Information

Dear Colleagues,

RNA viruses are characterized by the use of RNA as genetic material. Compared to their DNA counterparts, RNA viruses generally have smaller genomes and present a wider range of genetic diversity, due to the combined effect of a lower fidelity of replication and a higher incidence of genetic recombination. These features make RNA viruses extraordinary evolution machines. In cells, RNAs are generally associated with proteins in ribonucleic complexes (RNPs) that are in charge of addressing the RNAs to the appropriate cellular compartments and regulate their functions. To efficiently ensure viral replication, RNA genomes also associate with viral proteins to form vRNPs. These functional units are key players of the infectious cycle, driving various processes such as transcription and translation, as well as more specialized functions, including intracellular trafficking pathways for targeting viral components to assembly sites and consequently packaging viral genomic RNA into virions. Besides, determining the molecular organization and structure of vRNP is essential for unravelling the molecular mechanisms underlying the functions they are involved in. This Special Issue focuses on the interplay between viral components and aims to describe and better understand the structure and the function of RNPs in viral infection.

Dr. Serena Bernacchi
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Viruses is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • virus
  • viral proteins
  • viral RNA
  • ribonucleoproteins complexes
  • function
  • structure
  • viral replication

Published Papers (15 papers)

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Editorial

Jump to: Research, Review

4 pages, 188 KiB  
Editorial
Special Issue “Function and Structure of Viral Ribonucleoproteins Complexes”
by Serena Bernacchi
Viruses 2020, 12(12), 1355; https://doi.org/10.3390/v12121355 - 26 Nov 2020
Cited by 1 | Viewed by 1471
Abstract
RNA viruses are extraordinary evolution machines that efficiently ensure their replication by taking advantage of the association with viral and cellular components to form ribonucleic complexes (vRNPs) [...] Full article
(This article belongs to the Special Issue Function and Structure of Viral Ribonucleoproteins Complexes)

Research

Jump to: Editorial, Review

26 pages, 7635 KiB  
Article
HIV-1 Gag Forms Ribonucleoprotein Complexes with Unspliced Viral RNA at Transcription Sites
by Kevin M. Tuffy, Rebecca J. Kaddis Maldonado, Jordan Chang, Paul Rosenfeld, Alan Cochrane and Leslie J. Parent
Viruses 2020, 12(11), 1281; https://doi.org/10.3390/v12111281 - 9 Nov 2020
Cited by 18 | Viewed by 3183
Abstract
The ability of the retroviral Gag protein of Rous sarcoma virus (RSV) to transiently traffic through the nucleus is well-established and has been implicated in genomic RNA (gRNA) packaging Although other retroviral Gag proteins (human immunodeficiency virus type 1, HIV-1; feline immunodeficiency virus, [...] Read more.
The ability of the retroviral Gag protein of Rous sarcoma virus (RSV) to transiently traffic through the nucleus is well-established and has been implicated in genomic RNA (gRNA) packaging Although other retroviral Gag proteins (human immunodeficiency virus type 1, HIV-1; feline immunodeficiency virus, FIV; Mason-Pfizer monkey virus, MPMV; mouse mammary tumor virus, MMTV; murine leukemia virus, MLV; and prototype foamy virus, PFV) have also been observed in the nucleus, little is known about what, if any, role nuclear trafficking plays in those viruses. In the case of HIV-1, the Gag protein interacts in nucleoli with the regulatory protein Rev, which facilitates nuclear export of gRNA. Based on the knowledge that RSV Gag forms viral ribonucleoprotein (RNPs) complexes with unspliced viral RNA (USvRNA) in the nucleus, we hypothesized that the interaction of HIV-1 Gag with Rev could be mediated through vRNA to form HIV-1 RNPs. Using inducible HIV-1 proviral constructs, we visualized HIV-1 Gag and USvRNA in discrete foci in the nuclei of HeLa cells by confocal microscopy. Two-dimensional co-localization and RNA-immunoprecipitation of fractionated cells revealed that interaction of nuclear HIV-1 Gag with USvRNA was specific. Interestingly, treatment of cells with transcription inhibitors reduced the number of HIV-1 Gag and USvRNA nuclear foci, yet resulted in an increase in the degree of Gag co-localization with USvRNA, suggesting that Gag accumulates on newly synthesized viral transcripts. Three-dimensional imaging analysis revealed that HIV-1 Gag localized to the perichromatin space and associated with USvRNA and Rev in a tripartite RNP complex. To examine a more biologically relevant cell, latently infected CD4+ T cells were treated with prostratin to stimulate NF-κB mediated transcription, demonstrating striking localization of full-length Gag at HIV-1 transcriptional burst site, which was labelled with USvRNA-specific riboprobes. In addition, smaller HIV-1 RNPs were observed in the nuclei of these cells. These data suggest that HIV-1 Gag binds to unspliced viral transcripts produced at the proviral integration site, forming vRNPs in the nucleus. Full article
(This article belongs to the Special Issue Function and Structure of Viral Ribonucleoproteins Complexes)
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18 pages, 4010 KiB  
Article
How HIV-1 Integrase Associates with Human Mitochondrial Lysyl-tRNA Synthetase
by Xaysongkhame Phongsavanh, Noha Al-Qatabi, Mohammed Samer Shaban, Fawzi Khoder-Agha, Merwan El Asri, Martine Comisso, Raphaël Guérois and Marc Mirande
Viruses 2020, 12(10), 1202; https://doi.org/10.3390/v12101202 - 21 Oct 2020
Cited by 3 | Viewed by 2954
Abstract
Replication of human immunodeficiency virus type 1 (HIV-1) requires the packaging of tRNALys,3 from the host cell into the new viral particles. The GagPol viral polyprotein precursor associates with mitochondrial lysyl-tRNA synthetase (mLysRS) in a complex with tRNALys, an essential [...] Read more.
Replication of human immunodeficiency virus type 1 (HIV-1) requires the packaging of tRNALys,3 from the host cell into the new viral particles. The GagPol viral polyprotein precursor associates with mitochondrial lysyl-tRNA synthetase (mLysRS) in a complex with tRNALys, an essential step to initiate reverse transcription in the virions. The C-terminal integrase moiety of GagPol is essential for its association with mLysRS. We show that integrases from HIV-1 and HIV-2 bind mLysRS with the same efficiency. In this work, we have undertaken to probe the three-dimensional (3D) architecture of the complex of integrase with mLysRS. We first established that the C-terminal domain (CTD) of integrase is the major interacting domain with mLysRS. Using the pBpa-photo crosslinking approach, inter-protein cross-links were observed involving amino acid residues located at the surface of the catalytic domain of mLysRS and of the CTD of integrase. In parallel, using molecular docking simulation, a single structural model of complex was found to outscore other alternative conformations. Consistent with crosslinking experiments, this structural model was further probed experimentally. Five compensatory mutations in the two partners were successfully designed which supports the validity of the model. The complex highlights that binding of integrase could stabilize the tRNALys:mLysRS interaction. Full article
(This article belongs to the Special Issue Function and Structure of Viral Ribonucleoproteins Complexes)
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21 pages, 6041 KiB  
Article
Characterization of a DCL2-Insensitive Tomato Bushy Stunt Virus Isolate Infecting Arabidopsis thaliana
by Marco Incarbone, Hélene Scheer, Jean-Michel Hily, Lauriane Kuhn, Mathieu Erhardt, Patrice Dunoyer, Denise Altenbach and Christophe Ritzenthaler
Viruses 2020, 12(10), 1121; https://doi.org/10.3390/v12101121 - 2 Oct 2020
Cited by 2 | Viewed by 3802
Abstract
Tomato bushy stunt virus (TBSV), the type member of the genus Tombusvirus in the family Tombusviridae is one of the best studied plant viruses. The TBSV natural and experimental host range covers a wide spectrum of plants including agricultural crops, ornamentals, vegetables and [...] Read more.
Tomato bushy stunt virus (TBSV), the type member of the genus Tombusvirus in the family Tombusviridae is one of the best studied plant viruses. The TBSV natural and experimental host range covers a wide spectrum of plants including agricultural crops, ornamentals, vegetables and Nicotiana benthamiana. However, Arabidopsis thaliana, the well-established model organism in plant biology, genetics and plant–microbe interactions is absent from the list of known TBSV host plant species. Most of our recent knowledge of the virus life cycle has emanated from studies in Saccharomyces cerevisiae, a surrogate host for TBSV that lacks crucial plant antiviral mechanisms such as RNA interference (RNAi). Here, we identified and characterized a TBSV isolate able to infect Arabidopsis with high efficiency. We demonstrated by confocal and 3D electron microscopy that in Arabidopsis TBSV-BS3Ng replicates in association with clustered peroxisomes in which numerous spherules are induced. A dsRNA-centered immunoprecipitation analysis allowed the identification of TBSV-associated host components including DRB2 and DRB4, which perfectly localized to replication sites, and NFD2 that accumulated in larger viral factories in which peroxisomes cluster. By challenging knock-out mutants for key RNAi factors, we showed that TBSV-BS3Ng undergoes a non-canonical RNAi defensive reaction. In fact, unlike other RNA viruses described, no 22nt TBSV-derived small RNA are detected in the absence of DCL4, indicating that this virus is DCL2-insensitive. The new Arabidopsis-TBSV-BS3Ng pathosystem should provide a valuable new model for dissecting plant–virus interactions in complement to Saccharomyces cerevisiae. Full article
(This article belongs to the Special Issue Function and Structure of Viral Ribonucleoproteins Complexes)
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16 pages, 2364 KiB  
Article
Differential Behaviours and Preferential Bindings of Influenza Nucleoproteins on Importins-α
by Amélie Donchet, Emilie Vassal-Stermann, Francine C. A. Gérard, Rob W. H. Ruigrok and Thibaut Crépin
Viruses 2020, 12(8), 834; https://doi.org/10.3390/v12080834 - 30 Jul 2020
Cited by 3 | Viewed by 2819
Abstract
Influenza viruses are negative single-stranded RNA viruses with nuclear transcription and replication. They enter the nucleus by using the cellular importin-α/-β nuclear import machinery. Influenza nucleoproteins from influenza A, B, C and D viruses possess a nuclear localization signal (NLS) localized on an [...] Read more.
Influenza viruses are negative single-stranded RNA viruses with nuclear transcription and replication. They enter the nucleus by using the cellular importin-α/-β nuclear import machinery. Influenza nucleoproteins from influenza A, B, C and D viruses possess a nuclear localization signal (NLS) localized on an intrinsically disordered extremity (NPTAIL). In this paper, using size exclusion chromatography (SEC), SEC-multi-angle laser light scattering (SEC-MALLS) analysis, surface plasmon resonance (SPR) and fluorescence anisotropy, we provide the first comparative study designed to dissect the interaction between the four NPTAILs and four importins-α identified as partners. All interactions between NPTAILs and importins-α have high association and dissociation rates and present a distinct and specific behaviour. D/NPTAIL interacts strongly with all importins-α while B/NPTAIL shows weak affinity for importins-α. A/NPTAIL and C/NPTAIL present preferential importin-α partners. Mutations in B/NPTAIL and D/NPTAIL show a loss of importin-α binding, confirming key NLS residues. Taken together, our results provide essential highlights of this complex translocation mechanism. Full article
(This article belongs to the Special Issue Function and Structure of Viral Ribonucleoproteins Complexes)
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Review

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29 pages, 2287 KiB  
Review
Role of Viral Ribonucleoproteins in Human Papillomavirus Type 16 Gene Expression
by Naoko Kajitani and Stefan Schwartz
Viruses 2020, 12(10), 1110; https://doi.org/10.3390/v12101110 - 30 Sep 2020
Cited by 14 | Viewed by 3868
Abstract
Human papillomaviruses (HPVs) depend on the cellular RNA-processing machineries including alternative RNA splicing and polyadenylation to coordinate HPV gene expression. HPV RNA processing is controlled by cis-regulatory RNA elements and trans-regulatory factors since the HPV splice sites are suboptimal. The definition of HPV [...] Read more.
Human papillomaviruses (HPVs) depend on the cellular RNA-processing machineries including alternative RNA splicing and polyadenylation to coordinate HPV gene expression. HPV RNA processing is controlled by cis-regulatory RNA elements and trans-regulatory factors since the HPV splice sites are suboptimal. The definition of HPV exons and introns may differ between individual HPV mRNA species and is complicated by the fact that many HPV protein-coding sequences overlap. The formation of HPV ribonucleoproteins consisting of HPV pre-mRNAs and multiple cellular RNA-binding proteins may result in the different outcomes of HPV gene expression, which contributes to the HPV life cycle progression and HPV-associated cancer development. In this review, we summarize the regulation of HPV16 gene expression at the level of RNA processing with focus on the interactions between HPV16 pre-mRNAs and cellular RNA-binding factors. Full article
(This article belongs to the Special Issue Function and Structure of Viral Ribonucleoproteins Complexes)
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20 pages, 1667 KiB  
Review
Overview of the Nucleic-Acid Binding Properties of the HIV-1 Nucleocapsid Protein in Its Different Maturation States
by Assia Mouhand, Marco Pasi, Marjorie Catala, Loussiné Zargarian, Anissa Belfetmi, Pierre Barraud, Olivier Mauffret and Carine Tisné
Viruses 2020, 12(10), 1109; https://doi.org/10.3390/v12101109 - 29 Sep 2020
Cited by 11 | Viewed by 3298
Abstract
HIV-1 Gag polyprotein orchestrates the assembly of viral particles. Its C-terminus consists of the nucleocapsid (NC) domain that interacts with nucleic acids, and p1 and p6, two unstructured regions, p6 containing the motifs to bind ALIX, the cellular ESCRT factor TSG101 and the [...] Read more.
HIV-1 Gag polyprotein orchestrates the assembly of viral particles. Its C-terminus consists of the nucleocapsid (NC) domain that interacts with nucleic acids, and p1 and p6, two unstructured regions, p6 containing the motifs to bind ALIX, the cellular ESCRT factor TSG101 and the viral protein Vpr. The processing of Gag by the viral protease subsequently liberates NCp15 (NC-p1-p6), NCp9 (NC-p1) and NCp7, NCp7 displaying the optimal chaperone activity of nucleic acids. This review focuses on the nucleic acid binding properties of the NC domain in the different maturation states during the HIV-1 viral cycle. Full article
(This article belongs to the Special Issue Function and Structure of Viral Ribonucleoproteins Complexes)
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36 pages, 2103 KiB  
Review
Strength in Diversity: Nuclear Export of Viral RNAs
by Jón Pol Gales, Julie Kubina, Angèle Geldreich and Maria Dimitrova
Viruses 2020, 12(9), 1014; https://doi.org/10.3390/v12091014 - 11 Sep 2020
Cited by 17 | Viewed by 5708
Abstract
The nuclear export of cellular mRNAs is a complex process that requires the orchestrated participation of many proteins that are recruited during the early steps of mRNA synthesis and processing. This strategy allows the cell to guarantee the conformity of the messengers accessing [...] Read more.
The nuclear export of cellular mRNAs is a complex process that requires the orchestrated participation of many proteins that are recruited during the early steps of mRNA synthesis and processing. This strategy allows the cell to guarantee the conformity of the messengers accessing the cytoplasm and the translation machinery. Most transcripts are exported by the exportin dimer Nuclear RNA export factor 1 (NXF1)–NTF2-related export protein 1 (NXT1) and the transcription–export complex 1 (TREX1). Some mRNAs that do not possess all the common messenger characteristics use either variants of the NXF1–NXT1 pathway or CRM1, a different exportin. Viruses whose mRNAs are synthesized in the nucleus (retroviruses, the vast majority of DNA viruses, and influenza viruses) exploit both these cellular export pathways. Viral mRNAs hijack the cellular export machinery via complex secondary structures recognized by cellular export factors and/or viral adapter proteins. This way, the viral transcripts succeed in escaping the host surveillance system and are efficiently exported for translation, allowing the infectious cycle to proceed. This review gives an overview of the cellular mRNA nuclear export mechanisms and presents detailed insights into the most important strategies that viruses use to export the different forms of their RNAs from the nucleus to the cytoplasm. Full article
(This article belongs to the Special Issue Function and Structure of Viral Ribonucleoproteins Complexes)
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22 pages, 1992 KiB  
Review
Going beyond Integration: The Emerging Role of HIV-1 Integrase in Virion Morphogenesis
by Jennifer L. Elliott and Sebla B. Kutluay
Viruses 2020, 12(9), 1005; https://doi.org/10.3390/v12091005 - 9 Sep 2020
Cited by 18 | Viewed by 4862
Abstract
The HIV-1 integrase enzyme (IN) plays a critical role in the viral life cycle by integrating the reverse-transcribed viral DNA into the host chromosome. This function of IN has been well studied, and the knowledge gained has informed the design of small molecule [...] Read more.
The HIV-1 integrase enzyme (IN) plays a critical role in the viral life cycle by integrating the reverse-transcribed viral DNA into the host chromosome. This function of IN has been well studied, and the knowledge gained has informed the design of small molecule inhibitors that now form key components of antiretroviral therapy regimens. Recent discoveries unveiled that IN has an under-studied yet equally vital second function in human immunodeficiency virus type 1 (HIV-1) replication. This involves IN binding to the viral RNA genome in virions, which is necessary for proper virion maturation and morphogenesis. Inhibition of IN binding to the viral RNA genome results in mislocalization of the viral genome inside the virus particle, and its premature exposure and degradation in target cells. The roles of IN in integration and virion morphogenesis share a number of common elements, including interaction with viral nucleic acids and assembly of higher-order IN multimers. Herein we describe these two functions of IN within the context of the HIV-1 life cycle, how IN binding to the viral genome is coordinated by the major structural protein, Gag, and discuss the value of targeting the second role of IN in virion morphogenesis. Full article
(This article belongs to the Special Issue Function and Structure of Viral Ribonucleoproteins Complexes)
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Graphical abstract

16 pages, 2304 KiB  
Review
Advances in Continuous Microfluidics-Based Technologies for the Study of HIV Infection
by Joëlle Eid, Marylène Mougel and Marius Socol
Viruses 2020, 12(9), 982; https://doi.org/10.3390/v12090982 - 4 Sep 2020
Cited by 9 | Viewed by 3820
Abstract
HIV-1 is the causative agent of acquired immunodeficiency syndrome (AIDS). It affects millions of people worldwide and the pandemic persists despite the implementation of highly active antiretroviral therapy. A wide spectrum of techniques has been implemented in order to diagnose and monitor AIDS [...] Read more.
HIV-1 is the causative agent of acquired immunodeficiency syndrome (AIDS). It affects millions of people worldwide and the pandemic persists despite the implementation of highly active antiretroviral therapy. A wide spectrum of techniques has been implemented in order to diagnose and monitor AIDS progression over the years. Besides the conventional approaches, microfluidics has provided useful methods for monitoring HIV-1 infection. In this review, we introduce continuous microfluidics as well as the fabrication and handling of microfluidic chips. We provide a review of the different applications of continuous microfluidics in AIDS diagnosis and progression and in the basic study of the HIV-1 life cycle. Full article
(This article belongs to the Special Issue Function and Structure of Viral Ribonucleoproteins Complexes)
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Graphical abstract

12 pages, 5758 KiB  
Review
Components and Architecture of the Rhabdovirus Ribonucleoprotein Complex
by Christiane Riedel, Alexandru A. Hennrich and Karl-Klaus Conzelmann
Viruses 2020, 12(9), 959; https://doi.org/10.3390/v12090959 - 29 Aug 2020
Cited by 16 | Viewed by 5433
Abstract
Rhabdoviruses, as single-stranded, negative-sense RNA viruses within the order Mononegavirales, are characterised by bullet-shaped or bacteroid particles that contain a helical ribonucleoprotein complex (RNP). Here, we review the components of the RNP and its higher-order structural assembly. Full article
(This article belongs to the Special Issue Function and Structure of Viral Ribonucleoproteins Complexes)
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24 pages, 4359 KiB  
Review
Structures and Functions of Viral 5′ Non-Coding Genomic RNA Domain-I in Group-B Enterovirus Infections
by Marie Glenet, Laetitia Heng, Domitille Callon, Anne-Laure Lebreil, Paul-Antoine Gretteau, Yohan Nguyen, Fatma Berri and Laurent Andreoletti
Viruses 2020, 12(9), 919; https://doi.org/10.3390/v12090919 - 21 Aug 2020
Cited by 10 | Viewed by 4097
Abstract
Group-B enteroviruses (EV-B) are ubiquitous naked single-stranded positive RNA viral pathogens that are responsible for common acute or persistent human infections. Their genome is composed in the 5′ end by a non-coding region, which is crucial for the initiation of the viral replication [...] Read more.
Group-B enteroviruses (EV-B) are ubiquitous naked single-stranded positive RNA viral pathogens that are responsible for common acute or persistent human infections. Their genome is composed in the 5′ end by a non-coding region, which is crucial for the initiation of the viral replication and translation processes. RNA domain-I secondary structures can interact with viral or cellular proteins to form viral ribonucleoprotein (RNP) complexes regulating viral genomic replication, whereas RNA domains-II to -VII (internal ribosome entry site, IRES) are known to interact with cellular ribosomal subunits to initiate the viral translation process. Natural 5′ terminally deleted viral forms lacking some genomic RNA domain-I secondary structures have been described in EV-B induced murine or human infections. Recent in vitro studies have evidenced that the loss of some viral RNP complexes in the RNA domain-I can modulate the viral replication and infectivity levels in EV-B infections. Moreover, the disruption of secondary structures of RNA domain-I could impair viral RNA sensing by RIG-I (Retinoic acid inducible gene I) or MDA5 (melanoma differentiation-associated protein 5) receptors, a way to overcome antiviral innate immune response. Overall, natural 5′ terminally deleted viral genomes resulting in the loss of various structures in the RNA domain-I could be major key players of host–cell interactions driving the development of acute or persistent EV-B infections. Full article
(This article belongs to the Special Issue Function and Structure of Viral Ribonucleoproteins Complexes)
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42 pages, 1496 KiB  
Review
How HIV-1 Gag Manipulates Its Host Cell Proteins: A Focus on Interactors of the Nucleocapsid Domain
by Jéromine Klingler, Halina Anton, Eléonore Réal, Manon Zeiger, Christiane Moog, Yves Mély and Emmanuel Boutant
Viruses 2020, 12(8), 888; https://doi.org/10.3390/v12080888 - 13 Aug 2020
Cited by 10 | Viewed by 6823
Abstract
The human immunodeficiency virus (HIV-1) polyprotein Gag (Group-specific antigen) plays a central role in controlling the late phase of the viral lifecycle. Considered to be only a scaffolding protein for a long time, the structural protein Gag plays determinate and specific roles in [...] Read more.
The human immunodeficiency virus (HIV-1) polyprotein Gag (Group-specific antigen) plays a central role in controlling the late phase of the viral lifecycle. Considered to be only a scaffolding protein for a long time, the structural protein Gag plays determinate and specific roles in HIV-1 replication. Indeed, via its different domains, Gag orchestrates the specific encapsidation of the genomic RNA, drives the formation of the viral particle by its auto-assembly (multimerization), binds multiple viral proteins, and interacts with a large number of cellular proteins that are needed for its functions from its translation location to the plasma membrane, where newly formed virions are released. Here, we review the interactions between HIV-1 Gag and 66 cellular proteins. Notably, we describe the techniques used to evidence these interactions, the different domains of Gag involved, and the implications of these interactions in the HIV-1 replication cycle. In the final part, we focus on the interactions involving the highly conserved nucleocapsid (NC) domain of Gag and detail the functions of the NC interactants along the viral lifecycle. Full article
(This article belongs to the Special Issue Function and Structure of Viral Ribonucleoproteins Complexes)
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21 pages, 7088 KiB  
Review
Brothers in Arms: Structure, Assembly and Function of Arenaviridae Nucleoprotein
by Nicolas Papageorgiou, Maria Spiliopoulou, Thi-Hong Van Nguyen, Afroditi Vaitsopoulou, Elsie Yekwa Laban, Karine Alvarez, Irene Margiolaki, Bruno Canard and François Ferron
Viruses 2020, 12(7), 772; https://doi.org/10.3390/v12070772 - 17 Jul 2020
Cited by 12 | Viewed by 4575
Abstract
Arenaviridae is a family of viruses harbouring important emerging pathogens belonging to the Bunyavirales order. Like in other segmented negative strand RNA viruses, the nucleoprotein (NP) is a major actor of the viral life cycle being both (i) the necessary co-factor of the [...] Read more.
Arenaviridae is a family of viruses harbouring important emerging pathogens belonging to the Bunyavirales order. Like in other segmented negative strand RNA viruses, the nucleoprotein (NP) is a major actor of the viral life cycle being both (i) the necessary co-factor of the polymerase present in the L protein, and (ii) the last line of defence of the viral genome (vRNA) by physically hiding its presence in the cytoplasm. The NP is also one of the major players interfering with the immune system. Several structural studies of NP have shown that it features two domains: a globular RNA binding domain (NP-core) in its N-terminal and an exonuclease domain (ExoN) in its C-terminal. Further studies have observed that significant conformational changes are necessary for RNA encapsidation. In this review we revisited the most recent structural and functional data available on Arenaviridae NP, compared to other Bunyavirales nucleoproteins and explored the structural and functional implications. We review the variety of structural motif extensions involved in NP–NP binding mode. We also evaluate the major functional implications of NP interactome and the role of ExoN, thus making the NP a target of choice for future vaccine and antiviral therapy. Full article
(This article belongs to the Special Issue Function and Structure of Viral Ribonucleoproteins Complexes)
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23 pages, 5145 KiB  
Review
Phosphorylation of the Arginine-Rich C-Terminal Domains of the Hepatitis B Virus (HBV) Core Protein as a Fine Regulator of the Interaction between HBc and Nucleic Acid
by Hugues de Rocquigny, Virgile Rat, Florentin Pastor, Jean Luc Darlix, Christophe Hourioux and Philippe Roingeard
Viruses 2020, 12(7), 738; https://doi.org/10.3390/v12070738 - 8 Jul 2020
Cited by 22 | Viewed by 4672
Abstract
The morphogenesis of Hepatitis B Virus (HBV) viral particles is nucleated by the oligomerization of HBc protein molecules, resulting in the formation of an icosahedral capsid shell containing the replication-competent nucleoprotein complex made of the viral polymerase and the pre-genomic RNA (pgRNA). HBc [...] Read more.
The morphogenesis of Hepatitis B Virus (HBV) viral particles is nucleated by the oligomerization of HBc protein molecules, resulting in the formation of an icosahedral capsid shell containing the replication-competent nucleoprotein complex made of the viral polymerase and the pre-genomic RNA (pgRNA). HBc is a phospho-protein containing two distinct domains acting together throughout the viral replication cycle. The N-terminal domain, (residues 1–140), shown to self-assemble, is linked by a short flexible domain to the basic C-terminal domain (residues 150–183) that interacts with nucleic acids (NAs). In addition, the C-terminal domain contains a series of phospho-acceptor residues that undergo partial phosphorylation and de-phosphorylation during virus replication. This highly dynamic process governs the homeostatic charge that is essential for capsid stability, pgRNA packaging and to expose the C-terminal domain at the surface of the particles for cell trafficking. In this review, we discuss the roles of the N-terminal and C-terminal domains of HBc protein during HBV morphogenesis, focusing on how the C-terminal domain phosphorylation dynamics regulate its interaction with nucleic acids throughout the assembly and maturation of HBV particles. Full article
(This article belongs to the Special Issue Function and Structure of Viral Ribonucleoproteins Complexes)
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