1
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Visentin A, Demitroff N, Salgueiro M, Borkosky SS, Uversky VN, Camporeale G, de Prat-Gay G. Assembly of the Tripartite and RNA Condensates of the Respiratory Syncytial Virus Factory Proteins In Vitro: Role of the Transcription Antiterminator M 2-1. Viruses 2023; 15:1329. [PMID: 37376628 DOI: 10.3390/v15061329] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/01/2023] [Accepted: 06/02/2023] [Indexed: 06/29/2023] Open
Abstract
A wide variety of viruses replicate in liquid-like viral factories. Non-segmented negative stranded RNA viruses share a nucleoprotein (N) and a phosphoprotein (P) that together emerge as the main drivers of liquid-liquid phase separation. The respiratory syncytial virus includes the transcription antiterminator M2-1, which binds RNA and maximizes RNA transcriptase processivity. We recapitulate the assembly mechanism of condensates of the three proteins and the role played by RNA. M2-1 displays a strong propensity for condensation by itself and with RNA through the formation of electrostatically driven protein-RNA coacervates based on the amphiphilic behavior of M2-1 and finely tuned by stoichiometry. M2-1 incorporates into tripartite condensates with N and P, modulating their size through an interplay with P, where M2-1 is both client and modulator. RNA is incorporated into the tripartite condensates adopting a heterogeneous distribution, reminiscent of the M2-1-RNA IBAG granules within the viral factories. Ionic strength dependence indicates that M2-1 behaves differently in the protein phase as opposed to the protein-RNA phase, in line with the subcompartmentalization observed in viral factories. This work dissects the biochemical grounds for the formation and fate of the RSV condensates in vitro and provides clues to interrogate the mechanism under the highly complex infection context.
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Affiliation(s)
- Araceli Visentin
- Instituto Leloir, IIB-BA Conicet, Av. Patricias Argentinas 435, Buenos Aires 1405, Argentina
| | - Nicolás Demitroff
- Instituto Leloir, IIB-BA Conicet, Av. Patricias Argentinas 435, Buenos Aires 1405, Argentina
| | - Mariano Salgueiro
- Instituto Leloir, IIB-BA Conicet, Av. Patricias Argentinas 435, Buenos Aires 1405, Argentina
| | - Silvia Susana Borkosky
- Instituto Leloir, IIB-BA Conicet, Av. Patricias Argentinas 435, Buenos Aires 1405, Argentina
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Gabriela Camporeale
- Instituto Leloir, IIB-BA Conicet, Av. Patricias Argentinas 435, Buenos Aires 1405, Argentina
| | - Gonzalo de Prat-Gay
- Instituto Leloir, IIB-BA Conicet, Av. Patricias Argentinas 435, Buenos Aires 1405, Argentina
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials (CNPEM), Campinas 13083-970, SP, Brazil
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2
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Gao Y, Cao D, Pawnikar S, John KP, Ahn HM, Hill S, Ha JM, Parikh P, Ogilvie C, Swain A, Yang A, Bell A, Salazar A, Miao Y, Liang B. Structure of the Human Respiratory Syncytial Virus M2-1 Protein in Complex with a Short Positive-Sense Gene-End RNA. Structure 2020; 28:979-990.e4. [PMID: 32697936 DOI: 10.1016/j.str.2020.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 06/19/2020] [Accepted: 07/01/2020] [Indexed: 12/25/2022]
Abstract
The M2-1 protein of human respiratory syncytial virus (HRSV) is a transcription anti-terminator that regulates the processivity of the HRSV RNA-dependent RNA polymerase (RdRP). Here, we report a crystal structure of HRSV M2-1 bound to a short positive-sense gene-end RNA (SH7) at 2.7 Å resolution. We identified multiple critical residues of M2-1 involved in RNA interaction and examined their roles using mutagenesis and MicroScale Thermophoresis (MST) assay. We found that hydrophobic residue Phe23 is indispensable for M2-1 to recognize the base of RNA. We also captured spontaneous binding of RNA (SH7) to M2-1 in all-atom simulations using a robust Gaussian accelerated molecular dynamics (GaMD) method. Both experiments and simulations revealed that the interactions of RNA with two separate domains of M2-1, the zinc-binding domain (ZBD) and the core domain (CD), are independent of each other. Collectively, our results provided a structural basis for RNA recognition by HRSV M2-1.
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Affiliation(s)
- Yunrong Gao
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322 USA
| | - Dongdong Cao
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322 USA
| | - Shristi Pawnikar
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66047, USA
| | - Karen P John
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66047, USA
| | - Hyunjun Max Ahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322 USA
| | - Shaylan Hill
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322 USA
| | - Ju Mi Ha
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322 USA
| | - Priyal Parikh
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322 USA
| | - Claire Ogilvie
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322 USA
| | - Anshuman Swain
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322 USA
| | - Amy Yang
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322 USA
| | - Amber Bell
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322 USA
| | - Angela Salazar
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322 USA
| | - Yinglong Miao
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66047, USA.
| | - Bo Liang
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322 USA.
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Esperante SA, Alvarez-Paggi D, Salgueiro M, Prat Gay GD. Mechanism of Tetramer Dissociation, Unfolding, and Oligomer Assembly of Pneumovirus M2-1 Transcription Antiterminators. ACS OMEGA 2018; 3:14732-14745. [PMID: 30555987 PMCID: PMC6289497 DOI: 10.1021/acsomega.8b01600] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 10/17/2018] [Indexed: 06/09/2023]
Abstract
Among Mononegavirales, the Pneumovirus family stands out by its RNA polymerase processivity that relies on a transcription antiterminator, the M2-1 protein, which also plays a key role in viral particle assembly. Biophysical and structural evidence shows that this RNA-binding tetramer is strongly modulated by a CCCH Zn2+ binding motif. We show that while the global dissociation/unfolding free energy is 10 kcal mol-1, more stable for the respiratory syncytial virus M2-1, the human metapneumovirus (HMPV) counterpart shows a 7 kcal mol-1 higher intersubunit affinity. Removal of Zn2+ from both homologues leads to an apo-monomer of identical secondary structure that further undergoes a slow irreversible oligomerization. Mutation of the histidine residue of the Zn2+ motif to cysteine or alanine leads directly to large oligomers, strongly suggesting that metal coordination has an exquisite precision for modulating the quaternary arrangement. Zn2+ removal is very slow and requires subdenaturing concentrations of guanidine chloride, suggesting a likely local folding energy barrier. Exploring a broad combination of denaturant and ethylenediaminetetraacetic acid conditions, we showed that the metapneumovirus protein has to overcome a higher energy barrier to trigger Zn2+ removal-driven dissociation, in concordance with a slower dissociation kinetics. In silico modeling of open and close conformations for both M2-1 tetramers together with interaction energy calculations reveals that the gradual opening of protomers decreases the number of intersubunit contacts. Half of the interaction energy holding each protomer in the tetramer comes from the CCCH motif, while HMPV-M2-1 harbors additional contacts between the CCCH motif of one subunit and the core domain of a protomer located in trans, allowing the rationalization of the experimental data obtained. Overall, the evidence points at a key role of the CCCH motif in switching between structural and consequently functional alternatives of the M2-1 protein.
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4
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Molina IG, Esperante SA, Marino-Buslje C, Chemes LB, de Prat-Gay G. Cooperative RNA Recognition by a Viral Transcription Antiterminator. J Mol Biol 2018; 430:777-792. [PMID: 29414675 DOI: 10.1016/j.jmb.2018.01.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/29/2018] [Accepted: 01/29/2018] [Indexed: 01/18/2023]
Abstract
RNA transcription of mononegavirales decreases gradually from the 3' leader promoter toward the 5' end of the genome, due to a decay in polymerase processivity. In the respiratory syncytial virus and metapneumovirus, the M2-1 protein ensures transcription anti-termination. Despite being a homotetramer, respiratory syncytial virus M2-1 binds two molecules of RNA of 13mer or longer per tetramer, and temperature-sensitive secondary structure in the RNA ligand is unfolded by stoichiometric interaction with M2-1. Fine quantitative analysis shows positive cooperativity, indicative of conformational asymmetry in the tetramer. RNA binds to M2-1 through a fast bimolecular association followed by slow rearrangements corresponding to an induced-fit mechanism, providing a sequential description of the time events of cooperativity. The first binding event of half of the RNA molecule to one of the sites increases the affinity of the second binding event on the adjacent contacting protomer by 15-fold, product of increased effective concentration caused by the entropic link. This mechanism allows for high-affinity binding with an otherwise relaxed sequence specificity, and instead suggests a yet undefined structural recognition signature in the RNA for modulating gene transcription. This work provides a basis for an essential event for understanding transcription antitermination in pneumoviruses and its counterpart Ebola virus VP30.
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Affiliation(s)
- Ivana G Molina
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Av. Patricias Argentinas 435, 1405 Buenos Aires, Argentina
| | - Sebastian A Esperante
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Av. Patricias Argentinas 435, 1405 Buenos Aires, Argentina
| | - Cristina Marino-Buslje
- Structural Bioinformatics Unit, Fundación Instituto Leloir and IIBBA-CONICET, Av. Patricias Argentinas 435, 1405 Buenos Aires, Argentina
| | - Lucía B Chemes
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Av. Patricias Argentinas 435, 1405 Buenos Aires, Argentina.
| | - Gonzalo de Prat-Gay
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA-CONICET, Av. Patricias Argentinas 435, 1405 Buenos Aires, Argentina.
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5
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Molina IG, Josts I, Almeida Hernandez Y, Esperante S, Salgueiro M, Garcia Alai MM, de Prat-Gay G, Tidow H. Structure and stability of the Human respiratory syncytial virus M 2-1 RNA-binding core domain reveals a compact and cooperative folding unit. Acta Crystallogr F Struct Biol Commun 2018; 74:23-30. [PMID: 29372904 PMCID: PMC5947689 DOI: 10.1107/s2053230x17017381] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 12/04/2017] [Indexed: 11/10/2022] Open
Abstract
Human syncytial respiratory virus is a nonsegmented negative-strand RNA virus with serious implications for respiratory disease in infants, and has recently been reclassified into a new family, Pneumoviridae. One of the main reasons for this classification is the unique presence of a transcriptional antiterminator, called M2-1. The puzzling mechanism of action of M2-1, which is a rarity among antiterminators in viruses and is part of the RNA polymerase complex, relies on dissecting the structure and function of this multidomain tetramer. The RNA-binding activity is located in a monomeric globular `core' domain, a high-resolution crystal structure of which is now presented. The structure reveals a compact domain which is superimposable on the full-length M2-1 tetramer, with additional electron density for the C-terminal tail that was not observed in the previous models. Moreover, its folding stability was determined through chemical denaturation, which shows that the secondary and tertiary structure unfold concomitantly, which is indicative of a two-state equilibrium. These results constitute a further step in the understanding of this unique RNA-binding domain, for which there is no sequence or structural counterpart outside this virus family, in addition to its implications in transcription regulation and its likeliness as an antiviral target.
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Affiliation(s)
- Ivana G. Molina
- Protein Structure–Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA–CONICET, Avenida Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
| | - Inokentijs Josts
- The Hamburg Centre for Ultrafast Imaging and Department of Chemistry, Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
| | - Yasser Almeida Hernandez
- The Hamburg Centre for Ultrafast Imaging and Department of Chemistry, Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
| | - Sebastian Esperante
- Protein Structure–Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA–CONICET, Avenida Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
| | - Mariano Salgueiro
- Protein Structure–Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA–CONICET, Avenida Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
| | - Maria M. Garcia Alai
- European Molecular Biology Laboratory (EMBL), Hamburg Unit, Notkestrasse 85, 22607 Hamburg, Germany
| | - Gonzalo de Prat-Gay
- Protein Structure–Function and Engineering Laboratory, Fundación Instituto Leloir and IIBBA–CONICET, Avenida Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
| | - Henning Tidow
- The Hamburg Centre for Ultrafast Imaging and Department of Chemistry, Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
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Structural dissection of human metapneumovirus phosphoprotein using small angle x-ray scattering. Sci Rep 2017; 7:14865. [PMID: 29093501 PMCID: PMC5665942 DOI: 10.1038/s41598-017-14448-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 10/10/2017] [Indexed: 12/21/2022] Open
Abstract
The phosphoprotein (P) is the main and essential cofactor of the RNA polymerase (L) of non-segmented, negative‐strand RNA viruses. P positions the viral polymerase onto its nucleoprotein–RNA template and acts as a chaperone of the nucleoprotein (N), thereby preventing nonspecific encapsidation of cellular RNAs. The phosphoprotein of human metapneumovirus (HMPV) forms homotetramers composed of a stable oligomerization domain (Pcore) flanked by large intrinsically disordered regions (IDRs). Here we combined x-ray crystallography of Pcore with small angle x-ray scattering (SAXS)-based ensemble modeling of the full-length P protein and several of its fragments to provide a structural description of P that captures its dynamic character, and highlights the presence of varyingly stable structural elements within the IDRs. We discuss the implications of the structural properties of HMPV P for the assembly and functioning of the viral transcription/replication machinery.
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7
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Abstract
Globally, as a leading agent of acute respiratory tract infections in children <5 years of age and the elderly, the human metapneumovirus (HMPV) has gained considerable attention. As inferred from studies comparing vaccinated and experimentally infected mice, the acquired immune response elicited by this pathogen fails to efficiently clear the virus from the airways, which leads to an exaggerated inflammatory response and lung damage. Furthermore, after disease resolution, there is a poor development of T and B cell immunological memory, which is believed to promote reinfections and viral spread in the community. In this article, we discuss the molecular mechanisms that shape the interactions of HMPV with host tissues that lead to pulmonary pathology and to the development of adaptive immunity that fails to protect against natural infections by this virus.
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8
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Phosphorylation of Human Metapneumovirus M2-1 Protein Upregulates Viral Replication and Pathogenesis. J Virol 2016; 90:7323-7338. [PMID: 27252537 DOI: 10.1128/jvi.00755-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 05/25/2016] [Indexed: 01/02/2023] Open
Abstract
UNLABELLED Human metapneumovirus (hMPV) is a major causative agent of upper- and lower-respiratory-tract infections in infants, the elderly, and immunocompromised individuals worldwide. Like all pneumoviruses, hMPV encodes the zinc binding protein M2-1, which plays important regulatory roles in RNA synthesis. The M2-1 protein is phosphorylated, but the specific role(s) of the phosphorylation in viral replication and pathogenesis remains unknown. In this study, we found that hMPV M2-1 is phosphorylated at amino acid residues S57 and S60. Subsequent mutagenesis found that phosphorylation is not essential for zinc binding activity and oligomerization, whereas inhibition of zinc binding activity abolished the phosphorylation and oligomerization of the M2-1 protein. Using a reverse genetics system, recombinant hMPVs (rhMPVs) lacking either one or both phosphorylation sites in the M2-1 protein were recovered. These recombinant viruses had a significant decrease in both genomic RNA replication and mRNA transcription. In addition, these recombinant viruses were highly attenuated in cell culture and cotton rats. Importantly, rhMPVs lacking phosphorylation in the M2-1 protein triggered high levels of neutralizing antibody and provided complete protection against challenge with wild-type hMPV. Collectively, these data demonstrated that phosphorylation of the M2-1 protein upregulates hMPV RNA synthesis, replication, and pathogenesis in vivo IMPORTANCE The pneumoviruses include many important human and animal pathogens, such as human respiratory syncytial virus (hRSV), hMPV, bovine RSV, and avian metapneumovirus (aMPV). Among these viruses, hRSV and hMPV are the leading causes of acute respiratory tract infection in infants and children. Currently, there is no antiviral or vaccine to combat these diseases. All known pneumoviruses encode a zinc binding protein, M2-1, which is a transcriptional antitermination factor. In this work, we found that phosphorylation of M2-1 is essential for virus replication and pathogenesis in vivo Recombinant hMPVs lacking phosphorylation in M2-1 exhibited limited replication in the upper and lower respiratory tract and triggered strong protective immunity in cotton rats. This work highlights the important role of M2-1 phosphorylation in viral replication and that inhibition of M2-1 phosphorylation may serve as a novel approach to develop live attenuated vaccines as well as antiviral drugs for pneumoviruses.
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9
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Schlereth J, Grünweller A, Biedenkopf N, Becker S, Hartmann RK. RNA binding specificity of Ebola virus transcription factor VP30. RNA Biol 2016; 13:783-98. [PMID: 27315567 DOI: 10.1080/15476286.2016.1194160] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
The transcription factor VP30 of the non-segmented RNA negative strand Ebola virus balances viral transcription and replication. Here, we comprehensively studied RNA binding by VP30. Using a novel VP30:RNA electrophoretic mobility shift assay, we tested truncated variants of 2 potential natural RNA substrates of VP30 - the genomic Ebola viral 3'-leader region and its complementary antigenomic counterpart (each ∼155 nt in length) - and a series of other non-viral RNAs. Based on oligonucleotide interference, the major VP30 binding region on the genomic 3'-leader substrate was assigned to the internal expanded single-stranded region (∼ nt 125-80). Best binding to VP30 was obtained with ssRNAs of optimally ∼ 40 nt and mixed base composition; underrepresentation of purines or pyrimidines was tolerated, but homopolymeric sequences impaired binding. A stem-loop structure, particularly at the 3'-end or positioned internally, supports stable binding to VP30. In contrast, dsRNA or RNAs exposing large internal loops flanked by entirely helical arms on both sides are not bound. Introduction of a 5´-Cap(0) structure impaired VP30 binding. Also, ssDNAs bind substantially weaker than isosequential ssRNAs and heparin competes with RNA for binding to VP30, indicating that ribose 2'-hydroxyls and electrostatic contacts of the phosphate groups contribute to the formation of VP30:RNA complexes. Our results indicate a rather relaxed RNA binding specificity of filoviral VP30, which largely differs from that of the functionally related transcription factor of the Paramyxoviridae which binds to ssRNAs as short as 13 nt with a preference for oligo(A) sequences.
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Affiliation(s)
- Julia Schlereth
- a Institut für Pharmazeutische Chemie, Philipps-Universität Marburg , Marburg , Germany
| | - Arnold Grünweller
- a Institut für Pharmazeutische Chemie, Philipps-Universität Marburg , Marburg , Germany
| | - Nadine Biedenkopf
- b Institut für Virologie, Philipps-Universität Marburg , Marburg , Germany
| | - Stephan Becker
- b Institut für Virologie, Philipps-Universität Marburg , Marburg , Germany
| | - Roland K Hartmann
- a Institut für Pharmazeutische Chemie, Philipps-Universität Marburg , Marburg , Germany
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10
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Zhang X, Patel A, Celma CC, Yu X, Roy P, Zhou ZH. Atomic model of a nonenveloped virus reveals pH sensors for a coordinated process of cell entry. Nat Struct Mol Biol 2015; 23:74-80. [PMID: 26641711 PMCID: PMC5669276 DOI: 10.1038/nsmb.3134] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 11/04/2015] [Indexed: 12/28/2022]
Abstract
Viruses sense environmental cues (such as pH) to engage in membrane interactions for cell entry during infection but how non-enveloped viruses sense pH is largely undefined. Here, we report the structures — at high and low pH conditions — of bluetongue virus (BTV), which enters cells via a two-stage endosomal process. The receptor-binding protein VP2 possesses a zinc-finger and a conserved His866, which may function to maintain VP2 in a metastable state and to sense early-endosomal pH, respectively. The membrane penetration protein VP5 has three domains: dagger, unfurling, and anchoring. Notably, the β-meander motif of the anchoring domain contains a histidine cluster that could sense the late-endosomal pH and four putative membrane-interaction elements. Exposing BTV to low pH detaches VP2 and dramatically refolds the dagger and unfurling domains of VP5. Our biochemical and structure-guided mutagenesis studies support these coordinated pH-sensing mechanisms.
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Affiliation(s)
- Xing Zhang
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, California, USA
| | - Avnish Patel
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Cristina C Celma
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Xuekui Yu
- Department of Microbiology, Immunology &Molecular Genetics, UCLA, Los Angeles, California, USA
| | - Polly Roy
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Z Hong Zhou
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, California, USA.,Department of Microbiology, Immunology &Molecular Genetics, UCLA, Los Angeles, California, USA
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11
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Zinc binding activity of human metapneumovirus M2-1 protein is indispensable for viral replication and pathogenesis in vivo. J Virol 2015; 89:6391-405. [PMID: 25855728 DOI: 10.1128/jvi.03488-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 03/30/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Human metapneumovirus (hMPV) is a member of the Pneumovirinae subfamily in the Paramyxoviridae family that causes respiratory tract infections in humans. Unlike members of the Paramyxovirinae subfamily, the polymerase complex of pneumoviruses requires an additional cofactor, the M2-1 protein, which functions as a transcriptional antitermination factor. The M2-1 protein was found to incorporate zinc ions, although the specific role(s) of the zinc binding activity in viral replication and pathogenesis remains unknown. In this study, we found that the third cysteine (C21) and the last histidine (H25) in the zinc binding motif (CCCH) of hMPV M2-1 were essential for zinc binding activity, whereas the first two cysteines (C7 and C15) play only minor or redundant roles in zinc binding. In addition, the zinc binding motif is essential for the oligomerization of M2-1. Subsequently, recombinant hMPVs (rhMPVs) carrying mutations in the zinc binding motif were recovered. Interestingly, rhMPV-C21S and -H25L mutants, which lacked zinc binding activity, had delayed replication in cell culture and were highly attenuated in cotton rats. In contrast, rhMPV-C7S and -C15S strains, which retained 60% of the zinc binding activity, replicated as efficiently as rhMPV in cotton rats. Importantly, rhMPVs that lacked zinc binding activity triggered high levels of neutralizing antibody and provided complete protection against challenge with rhMPV. Taken together, these results demonstrate that zinc binding activity is indispensable for viral replication and pathogenesis in vivo. These results also suggest that inhibition of zinc binding activity may serve as a novel approach to rationally attenuate hMPV and perhaps other pneumoviruses for vaccine purposes. IMPORTANCE The pneumoviruses include many important human and animal pathogens, such as human respiratory syncytial virus (hRSV), hMPV, bovine RSV, and avian metapneumovirus (aMPV). Among these viruses, hRSV and hMPV are the leading causes of acute respiratory tract infection in infants and children. Despite major efforts, there is no antiviral or vaccine to combat these diseases. All known pneumoviruses encode a zinc binding protein, M2-1, which is a transcriptional antitermination factor. In this work, we found that the zinc binding activity of M2-1 is essential for virus replication and pathogenesis in vivo. Recombinant hMPVs that lacked zinc binding activity were not only defective in replication in the upper and lower respiratory tract but also triggered a strong protective immunity in cotton rats. Thus, inhibition of M2-1 zinc binding activity can lead to the development of novel, live attenuated vaccines, as well as antiviral drugs for pneumoviruses.
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12
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Brown PA, Lemaitre E, Briand FX, Courtillon C, Guionie O, Allée C, Toquin D, Bayon-Auboyer MH, Jestin V, Eterradossi N. Molecular comparisons of full length metapneumovirus (MPV) genomes, including newly determined French AMPV-C and -D isolates, further supports possible subclassification within the MPV Genus. PLoS One 2014; 9:e102740. [PMID: 25036224 PMCID: PMC4103871 DOI: 10.1371/journal.pone.0102740] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 06/20/2014] [Indexed: 01/12/2023] Open
Abstract
Four avian metapneumovirus (AMPV) subgroups (A-D) have been reported previously based on genetic and antigenic differences. However, until now full length sequences of the only known isolates of European subgroup C and subgroup D viruses (duck and turkey origin, respectively) have been unavailable. These full length sequences were determined and compared with other full length AMPV and human metapneumoviruses (HMPV) sequences reported previously, using phylogenetics, comparisons of nucleic and amino acid sequences and study of codon usage bias. Results confirmed that subgroup C viruses were more closely related to HMPV than they were to the other AMPV subgroups in the study. This was consistent with previous findings using partial genome sequences. Closer relationships between AMPV-A, B and D were also evident throughout the majority of results. Three metapneumovirus "clusters" HMPV, AMPV-C and AMPV-A, B and D were further supported by codon bias and phylogenetics. The data presented here together with those of previous studies describing antigenic relationships also between AMPV-A, B and D and between AMPV-C and HMPV may call for a subclassification of metapneumoviruses similar to that used for avian paramyxoviruses, grouping AMPV-A, B and D as type I metapneumoviruses and AMPV-C and HMPV as type II.
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Affiliation(s)
- Paul A. Brown
- French Agency for Food, Environmental and Occupational Health Safety (ANSES), Avian and Rabbit Virology Immunology and Parasitology Unit (VIPAC), Université Européenne de Bretagne, Ploufragan/Plouzané laboratory, Ploufragan, France
| | - Evelyne Lemaitre
- French Agency for Food, Environmental and Occupational Health Safety (ANSES), Avian and Rabbit Virology Immunology and Parasitology Unit (VIPAC), Université Européenne de Bretagne, Ploufragan/Plouzané laboratory, Ploufragan, France
| | - François-Xavier Briand
- French Agency for Food, Environmental and Occupational Health Safety (ANSES), Avian and Rabbit Virology Immunology and Parasitology Unit (VIPAC), Université Européenne de Bretagne, Ploufragan/Plouzané laboratory, Ploufragan, France
| | - Céline Courtillon
- French Agency for Food, Environmental and Occupational Health Safety (ANSES), Avian and Rabbit Virology Immunology and Parasitology Unit (VIPAC), Université Européenne de Bretagne, Ploufragan/Plouzané laboratory, Ploufragan, France
| | - Olivier Guionie
- French Agency for Food, Environmental and Occupational Health Safety (ANSES), Avian and Rabbit Virology Immunology and Parasitology Unit (VIPAC), Université Européenne de Bretagne, Ploufragan/Plouzané laboratory, Ploufragan, France
| | - Chantal Allée
- French Agency for Food, Environmental and Occupational Health Safety (ANSES), Avian and Rabbit Virology Immunology and Parasitology Unit (VIPAC), Université Européenne de Bretagne, Ploufragan/Plouzané laboratory, Ploufragan, France
| | - Didier Toquin
- French Agency for Food, Environmental and Occupational Health Safety (ANSES), Avian and Rabbit Virology Immunology and Parasitology Unit (VIPAC), Université Européenne de Bretagne, Ploufragan/Plouzané laboratory, Ploufragan, France
| | - Marie-Hélène Bayon-Auboyer
- French Agency for Food, Environmental and Occupational Health Safety (ANSES), Avian and Rabbit Virology Immunology and Parasitology Unit (VIPAC), Université Européenne de Bretagne, Ploufragan/Plouzané laboratory, Ploufragan, France
| | - Véronique Jestin
- French Agency for Food, Environmental and Occupational Health Safety (ANSES), Avian and Rabbit Virology Immunology and Parasitology Unit (VIPAC), Université Européenne de Bretagne, Ploufragan/Plouzané laboratory, Ploufragan, France
| | - Nicolas Eterradossi
- French Agency for Food, Environmental and Occupational Health Safety (ANSES), Avian and Rabbit Virology Immunology and Parasitology Unit (VIPAC), Université Européenne de Bretagne, Ploufragan/Plouzané laboratory, Ploufragan, France
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