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Sabariegos R, Ortega-Prieto AM, Díaz-Martínez L, Grande-Pérez A, García Crespo C, Gallego I, de Ávila AI, Albentosa-González L, Soria ME, Gastaminza P, Domingo E, Perales C, Mas A. Guanosine inhibits hepatitis C virus replication and increases indel frequencies, associated with altered intracellular nucleotide pools. PLoS Pathog 2022; 18:e1010210. [PMID: 35085375 PMCID: PMC8794218 DOI: 10.1371/journal.ppat.1010210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 12/16/2021] [Indexed: 12/30/2022] Open
Abstract
In the course of experiments aimed at deciphering the inhibition mechanism of mycophenolic acid and ribavirin in hepatitis C virus (HCV) infection, we observed an inhibitory effect of the nucleoside guanosine (Gua). Here, we report that Gua, and not the other standard nucleosides, inhibits HCV replication in human hepatoma cells. Gua did not directly inhibit the in vitro polymerase activity of NS5B, but it modified the intracellular levels of nucleoside di- and tri-phosphates (NDPs and NTPs), leading to deficient HCV RNA replication and reduction of infectious progeny virus production. Changes in the concentrations of NTPs or NDPs modified NS5B RNA polymerase activity in vitro, in particular de novo RNA synthesis and template switching. Furthermore, the Gua-mediated changes were associated with a significant increase in the number of indels in viral RNA, which may account for the reduction of the specific infectivity of the viral progeny, suggesting the presence of defective genomes. Thus, a proper NTP:NDP balance appears to be critical to ensure HCV polymerase fidelity and minimal production of defective genomes.
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Affiliation(s)
- Rosario Sabariegos
- Laboratorio de Virología Molecular, Centro Regional de Investigaciones Biomédicas (CRIB), Universidad de Castilla-La Mancha, Albacete, Spain
- Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain
- Unidad de Biomedicina UCLM-CSIC, Albacete, Spain
| | - Ana María Ortega-Prieto
- Centro de Biología Molecular “Severo Ochoa”, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Campus de Cantoblanco, Madrid, Spain
| | - Luis Díaz-Martínez
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora," Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHMS-UMA-CSIC), Málaga, Spain
- Área de Genética, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - Ana Grande-Pérez
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora," Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHMS-UMA-CSIC), Málaga, Spain
- Área de Genética, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - Carlos García Crespo
- Centro de Biología Molecular “Severo Ochoa”, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Campus de Cantoblanco, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Isabel Gallego
- Centro de Biología Molecular “Severo Ochoa”, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Campus de Cantoblanco, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Ana I. de Ávila
- Centro de Biología Molecular “Severo Ochoa”, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Campus de Cantoblanco, Madrid, Spain
| | - Laura Albentosa-González
- Laboratorio de Virología Molecular, Centro Regional de Investigaciones Biomédicas (CRIB), Universidad de Castilla-La Mancha, Albacete, Spain
| | - María Eugenia Soria
- Centro de Biología Molecular “Severo Ochoa”, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Campus de Cantoblanco, Madrid, Spain
- Department of Clinical Microbiology, IIS-Fundación Jiménez Díaz, UAM, Madrid, Spain
| | - Pablo Gastaminza
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
- Department of Cellular and Molecular Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, Madrid, Spain
| | - Esteban Domingo
- Unidad de Biomedicina UCLM-CSIC, Albacete, Spain
- Centro de Biología Molecular “Severo Ochoa”, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Campus de Cantoblanco, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
- * E-mail: (AM); (CP); (ED)
| | - Celia Perales
- Centro de Biología Molecular “Severo Ochoa”, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Campus de Cantoblanco, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
- Department of Clinical Microbiology, IIS-Fundación Jiménez Díaz, UAM, Madrid, Spain
- * E-mail: (AM); (CP); (ED)
| | - Antonio Mas
- Laboratorio de Virología Molecular, Centro Regional de Investigaciones Biomédicas (CRIB), Universidad de Castilla-La Mancha, Albacete, Spain
- Unidad de Biomedicina UCLM-CSIC, Albacete, Spain
- Facultad de Farmacia, Universidad de Castilla-La Mancha, Albacete, Spain
- * E-mail: (AM); (CP); (ED)
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2
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Sabariegos R, Albentosa-González L, Palmero B, Clemente-Casares P, Ramírez E, García-Crespo C, Gallego I, de Ávila AI, Perales C, Domingo E, Mas A. Akt Phosphorylation of Hepatitis C Virus NS5B Regulates Polymerase Activity and Hepatitis C Virus Infection. Front Microbiol 2021; 12:754664. [PMID: 34745059 PMCID: PMC8570118 DOI: 10.3389/fmicb.2021.754664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/20/2021] [Indexed: 11/13/2022] Open
Abstract
Hepatitis C virus (HCV) is a single-stranded RNA virus of positive polarity [ssRNA(+)] that replicates its genome through the activity of one of its proteins, called NS5B. This viral protein is responsible for copying the positive-polarity RNA genome into a negative-polarity RNA strand, which will be the template for new positive-polarity RNA genomes. The NS5B protein is phosphorylated by cellular kinases, including Akt. In this work, we have identified several amino acids of NS5B that are phosphorylated by Akt, with positions S27, T53, T267, and S282 giving the most robust results. Site-directed mutagenesis of these residues to mimic (Glu mutants) or prevent (Ala mutants) their phosphorylation resulted in a reduced NS5B in vitro RNA polymerase activity, except for the T267E mutant, the only non-conserved position of all those that are phosphorylated. In addition, in vitro transcribed RNAs derived from HCV complete infectious clones carrying mutations T53E/A and S282E/A were transfected in Huh-7.5 permissive cells, and supernatant viral titers were measured at 6 and 15 days post-transfection. No virus was rescued from the mutants except for T53A at 15 days post-transfection whose viral titer was statistically lower as compared to the wild type. Therefore, phosphorylation of NS5B by cellular kinases is a mechanism of viral polymerase inactivation. Whether this inactivation is a consequence of interaction with cellular kinases or a way to generate inactive NS5B that may have other functions are questions that need further experimental work.
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Affiliation(s)
- Rosario Sabariegos
- Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Albacete, Spain.,Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain.,Unidad de Biomedicina UCLM-CSIC, Madrid, Spain
| | - Laura Albentosa-González
- Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Blanca Palmero
- Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Pilar Clemente-Casares
- Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Albacete, Spain.,Unidad de Biomedicina UCLM-CSIC, Madrid, Spain.,Facultad de Farmacia, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Eugenio Ramírez
- Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Carlos García-Crespo
- Centro de Biología Molecular "Severo Ochoa" (CBMSO) (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Isabel Gallego
- Centro de Biología Molecular "Severo Ochoa" (CBMSO) (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Ana Isabel de Ávila
- Centro de Biología Molecular "Severo Ochoa" (CBMSO) (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Celia Perales
- Centro de Biología Molecular "Severo Ochoa" (CBMSO) (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain.,Department of Clinical Microbiology, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Esteban Domingo
- Unidad de Biomedicina UCLM-CSIC, Madrid, Spain.,Centro de Biología Molecular "Severo Ochoa" (CBMSO) (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Antonio Mas
- Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Albacete, Spain.,Unidad de Biomedicina UCLM-CSIC, Madrid, Spain.,Facultad de Farmacia, Universidad de Castilla-La Mancha, Albacete, Spain
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3
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Blackard JT, Davies SM, Laskin BL. BK polyomavirus diversity-Why viral variation matters. Rev Med Virol 2020; 30:e2102. [PMID: 32128960 DOI: 10.1002/rmv.2102] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 02/12/2020] [Accepted: 02/13/2020] [Indexed: 02/06/2023]
Abstract
BK polyomavirus (BKPyV or BKV) is a non-enveloped, circular double-stranded DNA virus that may exceed 80% seroprevalence in adults. BKV infection typically occurs during childhood, and the majority of adults are latently infected. While BKV infection is rarely associated with clinical disease in most individuals, in immunosuppressed individuals, reactivation may cause kidney (BK-associated nephropathy) or bladder (hemorrhagic cystitis and ureteral stenosis) injury. No antiviral therapies have been approved for the treatment of BKV infection. Reducing immunosuppression is the most effective therapy, although this is not feasible in many patients. Thus, a robust understanding of viral pathogenesis and viral diversity remains important for the development of future therapeutic strategies. Studies of BKV diversity are quite sparse compared to other common viral infections; thus, much of our understanding of BVK variability and evolution relies heavily analogous studies of other viruses such as HIV or viral hepatitis. We provide a comprehensive review of BKV diversity at the population and individual level with careful consideration of how viral variability may impact viral replication, pathogenesis, tropism, and protein function. We also discuss a number of outstanding questions related to BK virus diversity that should be explored rigorously in future studies.
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Affiliation(s)
- Jason T Blackard
- Division of Digestive Diseases, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Stella M Davies
- Division of Bone Marrow Transplantation and Immune Deficiency, Cincinnati Children's Hospital Medical Center and the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Benjamin L Laskin
- Division of Nephrology, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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Polymerase Activity, Protein-Protein Interaction, and Cellular Localization of the Usutu Virus NS5 Protein. Antimicrob Agents Chemother 2019; 64:AAC.01573-19. [PMID: 31685463 PMCID: PMC7187600 DOI: 10.1128/aac.01573-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 10/23/2019] [Indexed: 12/31/2022] Open
Abstract
Usutu virus (USUV) has become increasingly relevant in recent years, with large outbreaks that sporadically have affected humans being reported in wildlife. Similarly to the rest of flaviviruses, USUV contains a positive-sense single-stranded RNA genome which is replicated by the activity of nonstructural protein 5 (NS5). USUV NS5 shows high sequence identity with the remaining viruses in this genus. This permitted us to identify the predicted methyltransferase domain and the RNA-dependent RNA polymerase domain (RdRpD). Owing to their high degree of conservation, viral polymerases are considered priority targets for the development of antiviral compounds. In the present study, we cloned and expressed the entire NS5 and the RdRpD in a heterologous system and used purified preparations for protein characterizations. We determined the optimal reaction conditions by investigating how variations in different physicochemical parameters, such as buffer concentration, temperature, and pH, affect RNA polymerization activity. We also found that USUV polymerase, but not the full-length NS5, exhibits cooperative activity in the synthesis of RNA and that the RdRp activity is not inhibited by sofosbuvir. To further examine the characteristics of USUV polymerase in a more specifically biological context, we have expressed NS5 and the RdRpD in eukaryotic cells and analyzed their subcellular location. NS5 is predominantly found in the cytoplasm; a significant proportion is directed to the nucleus, and this translocation involves nuclear location signals (NLS) located at least between the MTase and RdRpD domains.
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5
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Ferrero DS, Ruiz-Arroyo VM, Soler N, Usón I, Guarné A, Verdaguer N. Supramolecular arrangement of the full-length Zika virus NS5. PLoS Pathog 2019; 15:e1007656. [PMID: 30951555 PMCID: PMC6469808 DOI: 10.1371/journal.ppat.1007656] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 04/17/2019] [Accepted: 02/23/2019] [Indexed: 12/12/2022] Open
Abstract
Zika virus (ZIKV), a member of the Flaviviridae family, has emerged as a major public health threat, since ZIKV infection has been connected to microcephaly and other neurological disorders. Flavivirus genome replication is driven by NS5, an RNA-dependent RNA polymerase (RdRP) that also contains a N-terminal methyltransferase domain essential for viral mRNA capping. Given its crucial roles, ZIKV NS5 has become an attractive antiviral target. Here, we have used integrated structural biology approaches to characterize the supramolecular arrangement of the full-length ZIKV NS5, highlighting the assembly and interfaces between NS5 monomers within a dimeric structure, as well as the dimer-dimer interactions to form higher order fibril-like structures. The relative orientation of each monomer within the dimer provides a model to explain the coordination between MTase and RdRP domains across neighboring NS5 molecules and mutational studies underscore the crucial role of the MTase residues Y25, K28 and K29 in NS5 dimerization. The basic residue K28 also participates in GTP binding and competition experiments indicate that NS5 dimerization is disrupted at high GTP concentrations. This competition represents a first glimpse at a molecular level explaining how dimerization might regulate the capping process. The lack of vaccine or antiviral drugs to combat Zika virus (ZIKV) infection has encouraged scientists to characterize in depth potential drug targets. One attractive candidate is NS5, responsible for the catalysis of the 5’-RNA capping, methylation and RNA synthesis, during flavivirus genome replication. To fulfill these activities, the methyltransferase and RNA-dependent RNA polymerase domains of NS5 need to cooperate with each other. The structural and biophysical data presented in this work demonstrate that the ZIKV NS5 protein has the ability to form dimers, as well as higher order oligomers that may participate in the fine-tuning regulation of the multiple enzyme functions in the replication complex. In addition, we have found that NS5 dimerization is disrupted at high GTP concentrations, explaining how dimerization might regulate the capping process.
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Affiliation(s)
- Diego S. Ferrero
- Structural Biology Unit, Institut de Biología Molecular de Barcelona CSIC, Barcelona, Spain
| | - Victor M. Ruiz-Arroyo
- Structural Biology Unit, Institut de Biología Molecular de Barcelona CSIC, Barcelona, Spain
| | - Nicolas Soler
- Structural Biology Unit, Institut de Biología Molecular de Barcelona CSIC, Barcelona, Spain
| | - Isabel Usón
- Structural Biology Unit, Institut de Biología Molecular de Barcelona CSIC, Barcelona, Spain
- ICREA Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
| | - Alba Guarné
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Núria Verdaguer
- Structural Biology Unit, Institut de Biología Molecular de Barcelona CSIC, Barcelona, Spain
- * E-mail:
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6
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Interaction of the intrinsically disordered C-terminal domain of the sesbania mosaic virus RNA-dependent RNA polymerase with the viral protein P10 in vitro: modulation of the oligomeric state and polymerase activity. Arch Virol 2019; 164:971-982. [PMID: 30721364 DOI: 10.1007/s00705-019-04163-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 01/09/2019] [Indexed: 12/13/2022]
Abstract
The RNA-dependent RNA polymerase (RdRp) of sesbania mosaic virus (SeMV) was previously shown to interact with the viral protein P10, which led to enhanced polymerase activity. In the present investigation, the equilibrium dissociation constant for the interaction between the two proteins was determined to be 0.09 µM using surface plasmon resonance, and the disordered C-terminal domain of RdRp was shown to be essential for binding to P10. The association with P10 brought about a change in the oligomeric state of RdRp, resulting in reduced aggregation and increased polymerase activity. Interestingly, unlike the wild-type RdRp, C-terminal deletion mutants (C del 43 and C del 72) were found to exist predominantly as monomers and were as active as the RdRp-P10 complex. Thus, either the deletion of the C-terminal disordered domain or its masking by binding to P10 results in the activation of polymerase activity. Further, deletion of the C-terminal 85 residues of RdRp resulted in complete loss of activity. Mutation of a conserved tyrosine (RdRp Y480) within motif E, located between 72 and 85 residues from the C-terminus of RdRp, rendered the protein inactive, demonstrating the importance of motif E in RNA synthesis in vitro.
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7
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Humes D, Ramirez S, Jensen TB, Li YP, Gottwein JM, Bukh J. Recombinant hepatitis C virus genotype 5a infectious cell culture systems expressing minimal JFH1 NS5B sequences permit polymerase inhibitor studies. Virology 2018; 522:177-192. [PMID: 30032031 DOI: 10.1016/j.virol.2018.05.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 05/24/2018] [Accepted: 05/25/2018] [Indexed: 02/07/2023]
Abstract
The six major epidemiologically important hepatitis C virus (HCV) genotypes differ in global distribution and antiviral responses. Full-length infectious cell-culture adapted clones, the gold standard for HCV studies in vitro, are missing for genotypes 4 and 5. To address this challenge for genotype 5, we constructed a consensus full-length clone of strain SA13 (SA13fl), which was found non-viable in Huh7.5 cells. Step-wise adaptation of SA13fl-based recombinants, beginning with a virus encoding the NS5B-thumb domain and 3´UTR of JFH1 (SA13/JF372-X), resulted in a high-titer SA13 virus with only 41 JFH1-encoded NS5B-thumb residues (SA13/JF470-510cc); this required sixteen cell-culture adaptive substitutions within the SA13fl polyprotein and two 3´UTR-changes. SA13/JF372-X and SA13/JF470-510cc were equally sensitive to nucleoside polymerase inhibitors, including sofosbuvir, but showed differential sensitivity to inhibitors targeting the NS5B palm or thumb. SA13/JF470-510cc represents a model to elucidate the influence of HCV RNA elements on viral replication and map determinants of sensitivity to polymerase inhibitors.
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Affiliation(s)
- Daryl Humes
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases and Clinical Research Centre, Hvidovre Hospital and Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Santseharay Ramirez
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases and Clinical Research Centre, Hvidovre Hospital and Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Tanja B Jensen
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases and Clinical Research Centre, Hvidovre Hospital and Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Yi-Ping Li
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases and Clinical Research Centre, Hvidovre Hospital and Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Judith M Gottwein
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases and Clinical Research Centre, Hvidovre Hospital and Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Jens Bukh
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases and Clinical Research Centre, Hvidovre Hospital and Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
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Abstract
Most emerging and re-emerging human and animal viral diseases are associated with RNA viruses. All these pathogens, with the exception of retroviruses, encode a specialized enzyme called RNA-dependent RNA polymerase (RdRP), which catalyze phosphodiester-bond formation between ribonucleotides (NTPs) in an RNA template-dependent manner. These enzymes function either as single polypeptides or in complex with other viral or host components to transcribe and replicate the viral RNA genome. The structures of RdRPs and RdRP catalytic complexes, currently available for several members of (+) ssRNA, (-)ssRNA and dsRNA virus families, have provided high resolution snapshots of the functional steps underlying replication and transcription of viral RNA genomes and their regulatory mechanisms.
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Affiliation(s)
- Diego Ferrero
- Structural Biology Unit, Institut de Biologia Molecular de Barcelona (IBMB-CSIC), Barcelona, Spain
| | - Cristina Ferrer-Orta
- Structural Biology Unit, Institut de Biologia Molecular de Barcelona (IBMB-CSIC), Barcelona, Spain
| | - Núria Verdaguer
- Structural Biology Unit, Institut de Biologia Molecular de Barcelona (IBMB-CSIC), Barcelona, Spain.
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9
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Cho NJ, Pham EA, Hagey RJ, Lévêque VJ, Ma H, Klumpp K, Glenn JS. Reconstitution and Functional Analysis of a Full-Length Hepatitis C Virus NS5B Polymerase on a Supported Lipid Bilayer. ACS CENTRAL SCIENCE 2016; 2:456-66. [PMID: 27504492 PMCID: PMC4965852 DOI: 10.1021/acscentsci.6b00112] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Indexed: 05/03/2023]
Abstract
Therapeutic targeting of membrane-associated viral proteins is complicated by the challenge of investigating their enzymatic activities in the native membrane-bound state. To permit functional characterization of these proteins, we hypothesized that the supported lipid bilayer (SLB) can support in situ reconstitution of membrane-associated viral protein complexes. As proof-of-principle, we selected the hepatitis C virus (HCV) NS5B polymerase which is essential for HCV genome replication, and determined that the SLB platform enables functional reconstitution of membrane protein activity. Quartz crystal microbalance with dissipation (QCM-D) monitoring enabled label-free detection of full-length NS5B membrane association, its interaction with replicase subunits NS3, NS5A, and template RNA, and most importantly its RNA synthesis activity. This latter activity could be inhibited by the addition of candidate small molecule drugs. Collectively, our results demonstrate that the SLB platform can support functional studies of membrane-associated viral proteins engaged in critical biological activities.
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Affiliation(s)
- Nam-Joon Cho
- Department
of Chemical Engineering, Stanford University, Palo Alto, California 94305, United States
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Palo Alto, California 94305, United States
| | - Edward A. Pham
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Palo Alto, California 94305, United States
- Department of Microbiology and Immunology, Stanford University School of Medicine, Palo Alto, California 94305, United States
| | - Rachel J. Hagey
- Department of Microbiology and Immunology, Stanford University School of Medicine, Palo Alto, California 94305, United States
| | - Vincent J. Lévêque
- Virology Discovery, Hoffmann-La Roche Inc., Nutley, New Jersey 07110, United States
| | - Han Ma
- Virology Discovery, Hoffmann-La Roche Inc., Nutley, New Jersey 07110, United States
| | - Klaus Klumpp
- Virology Discovery, Hoffmann-La Roche Inc., Nutley, New Jersey 07110, United States
| | - Jeffrey S. Glenn
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Palo Alto, California 94305, United States
- Department of Microbiology and Immunology, Stanford University School of Medicine, Palo Alto, California 94305, United States
- Veterans
Administration Medical Center, Palo Alto, California 94304, United States
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10
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Hepatitis C Virus RNA-Dependent RNA Polymerase Interacts with the Akt/PKB Kinase and Induces Its Subcellular Relocalization. Antimicrob Agents Chemother 2016; 60:3540-50. [PMID: 27021315 DOI: 10.1128/aac.03019-15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 03/18/2016] [Indexed: 02/07/2023] Open
Abstract
Hepatitis C virus (HCV) interacts with cellular components and modulates their activities for its own benefit. These interactions have been postulated as a target for antiviral treatment, and some candidate molecules are currently in clinical trials. The multifunctional cellular kinase Akt/protein kinase B (PKB) must be activated to increase the efficacy of HCV entry but is rapidly inactivated as the viral replication cycle progresses. Viral components have been postulated to be responsible for Akt/PKB inactivation, but the underlying mechanism remained elusive. In this study, we show that HCV polymerase NS5B interacts with Akt/PKB. In the presence of transiently expressed NS5B or in replicon- or virus-infected cells, NS5B changes the cellular localization of Akt/PKB from the cytoplasm to the perinuclear region. Sequestration of Akt/PKB by NS5B could explain its exclusion from its participation in early Akt/PKB inactivation. The NS5B-Akt/PKB interaction represents a new regulatory step in the HCV infection cycle, opening possibilities for new therapeutic options.
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Ferrero DS, Buxaderas M, Rodríguez JF, Verdaguer N. The Structure of the RNA-Dependent RNA Polymerase of a Permutotetravirus Suggests a Link between Primer-Dependent and Primer-Independent Polymerases. PLoS Pathog 2015; 11:e1005265. [PMID: 26625123 PMCID: PMC4666646 DOI: 10.1371/journal.ppat.1005265] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 10/19/2015] [Indexed: 11/18/2022] Open
Abstract
Thosea asigna virus (TaV), an insect virus belonging to the Permutatetraviridae family, has a positive-sense single-stranded RNA (ssRNA) genome with two overlapping open reading frames, encoding for the replicase and capsid proteins. The particular TaV replicase includes a structurally unique RNA-dependent RNA polymerase (RdRP) with a sequence permutation in the palm sub-domain, where the active site is anchored. This non-canonical arrangement of the RdRP palm is also found in double-stranded RNA viruses of the Birnaviridae family. Both virus families also share a conserved VPg sequence motif at the polymerase N-terminus which in birnaviruses appears to be used to covalently link a fraction of the replicase molecules to the 5’-end of the genomic segments. Birnavirus VPgs are presumed to be used as primers for replication initiation. Here we have solved the crystal structure of the TaV RdRP, the first non-canonical RdRP of a ssRNA virus, in its apo- form and bound to different substrates. The enzyme arranges as a stable dimer maintained by mutual interactions between the active site cleft of one molecule and the flexible N-terminal tail of the symmetrically related RdRP. The latter, partially mimicking the RNA template backbone, is involved in regulating the polymerization activity. As expected from previous sequence-based bioinformatics predictions, the overall architecture of the TaV enzyme shows important resemblances with birnavirus polymerases. In addition, structural comparisons and biochemical analyses reveal unexpected similarities between the TaV RdRP and those of Flaviviruses. In particular, a long loop protruding from the thumb domain towards the central enzyme cavity appears to act as a platform for de novo initiation of RNA replication. Our findings strongly suggest an unexpected evolutionary relationship between the RdRPs encoded by these distant ssRNA virus groups. RNA dependent RNA polymerases (RdRPs) are the catalytic components of the RNA replication and transcription machineries, and thus central players in the life cycle of RNA viruses. The in-depth understanding of both the structure and regulation of viral RdRPs displaying different replication-transcription strategies might provide essential clues for an effective control of virus propagation. The characterization of the first non-canonical RdRP of a positive-stranded RNA virus, the permutotetravirus Thosea asigna virus, has unveiled two essential elements controlling polymerization activity: (i) the protein N-terminus that invades the central cleft of the neighboring RdRP molecule, thus stabilizing a dimeric form of the enzyme with partially occluded template binding channels; and (ii) a long loop protruding towards the catalytic cavity which harbors the binding site of incoming nucleotides, thus providing a platform for de novo replication initiation. The close structural and functional resemblance between this enzyme and flaviviral RdRPs strongly suggests the existence of an unexpected evolutionary link between these two distant virus groups.
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Affiliation(s)
- Diego S. Ferrero
- Institut de Biologia Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Barcelona, Spain
- Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Mònica Buxaderas
- Institut de Biologia Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Barcelona, Spain
| | - José F. Rodríguez
- Centro Nacional de Biotecnología, CSIC, Madrid, Spain
- * E-mail: (JFR); (NV)
| | - Núria Verdaguer
- Institut de Biologia Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Barcelona, Spain
- * E-mail: (JFR); (NV)
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12
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Hernández S, Figueroa D, Correa S, Díaz A, Aguayo D, Villanueva RA. Phosphorylation at the N-terminal finger subdomain of a viral RNA-dependent RNA polymerase. Biochem Biophys Res Commun 2015; 466:21-7. [PMID: 26301630 DOI: 10.1016/j.bbrc.2015.08.082] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 08/19/2015] [Indexed: 01/29/2023]
Abstract
The RNA-dependent RNA polymerase (RdRP) of the Hepatitis C virus (HCV), named NS5B, is phosphorylated by the cellular protein kinase C-related kinase 2 (PRK2) at two serine residues (Ser29 and Ser42) of the finger subdomain (genotype 1b). Herein, using bioinformatics, we selected four potential phosphorylation residues (Ser46, Ser76, Ser96 and Ser112) of NS5B (genotype 2a) for study. Whereas the NS5B Ser46D and Ser76D substitutions seemed to improve polymerase activity, the Ser96D mutation decreased colony formation efficiency. Active WT NS5B was utilized in in vitro kinase assays, and phosphopeptides were analyzed by mass spectrometry. Interestingly, the data indicated that both the NS5B Ser29 and Ser76 residues resulted phosphorylated. Thus, as Ser76 is absolutely conserved across HCV genotypes, our results confirmed the relevance of these sites for both genotypes and suggested that Ser76 becomes phosphorylated by a cellular kinase different from PRK2. By molecular dynamic simulations, we show that new interactions between space-adjacent amino acid chains could be established by the presence of a di-anionic phosphate group on the analyzed serines to possibly modify RNA polymerase activity. Together, our data present novel evidence on the complex regulation at the finger subdomain of HCV NS5B via phosphorylation.
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Affiliation(s)
- Sergio Hernández
- Laboratorio de Virus Hepatitis, Departamento de Cs. Biológicas, Universidad Andrés Bello, Santiago, Chile
| | - Daniella Figueroa
- Laboratorio de Virus Hepatitis, Departamento de Cs. Biológicas, Universidad Andrés Bello, Santiago, Chile
| | - Simón Correa
- Centro de Bioinformática y Biología Integrativa, Facultad de Cs. Biológicas, Universidad Andrés Bello, Santiago, Chile
| | - Ariel Díaz
- Laboratorio de Virus Hepatitis, Departamento de Cs. Biológicas, Universidad Andrés Bello, Santiago, Chile
| | - Daniel Aguayo
- Centro de Bioinformática y Biología Integrativa, Facultad de Cs. Biológicas, Universidad Andrés Bello, Santiago, Chile; Centro Interdisciplinario de Neurociencia de Valparaíso, Valparaíso, Chile
| | - Rodrigo A Villanueva
- Laboratorio de Virus Hepatitis, Departamento de Cs. Biológicas, Universidad Andrés Bello, Santiago, Chile.
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13
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López-Jiménez AJ, Clemente-Casares P, Sabariegos R, Llanos-Valero M, Bellón-Echeverría I, Encinar JA, Kaushik-Basu N, Froeyen M, Mas A. Hepatitis C virus polymerase-polymerase contact interface: significance for virus replication and antiviral design. Antiviral Res 2014; 108:14-24. [PMID: 24815023 DOI: 10.1016/j.antiviral.2014.04.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/13/2014] [Accepted: 04/21/2014] [Indexed: 11/25/2022]
Abstract
The hepatitis C virus (HCV) replicates its genome in replication complexes located in micro-vesicles derived from endoplasmic reticulum. The composition of these replication complexes indicates that proteins, both viral and cellular in origin, are at high concentrations. Under these conditions, protein-protein interactions must occur although their role in the replication pathways is unknown. HCV RNA-dependent RNA-polymerase (NS5B) initiates RNA synthesis in these vesicles by a de novo (DN) mechanism. After initiation, newly synthesized dsRNA could induce conformational changes that direct the transition from an initiating complex into a processive elongation complex. In this report, we analyze the role played by NS5B-NS5B intermolecular interactions controlling these conformational rearrangements. Based on NS5B protein-protein docking and molecular dynamics simulations, we constructed mutants of residues predicted to be involved in protein-protein interactions. Changes at these positions induced severe defects in both the activity of the enzyme and the replication of a subgenomic replicon. Thus, mutations at the interaction surface decreased both DN synthesis initiation and processive elongation activities. Based on this analysis, we define at an atomic level an NS5B homomeric interaction model that connects the T-helix in the thumb subdomain of one monomer, with the F-helix of the fingers subdomain in other monomer. Knowing the molecular determinants involved in viral replication could be helpful to delineate new and powerful antiviral strategies.
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Affiliation(s)
- Alberto José López-Jiménez
- Centro Regional de Investigaciones Biomédicas (CRIB), Universidad de Castilla-La Mancha, Albacete 02008, Spain
| | - Pilar Clemente-Casares
- Centro Regional de Investigaciones Biomédicas (CRIB), Universidad de Castilla-La Mancha, Albacete 02008, Spain; School of Pharmacy, Universidad de Castilla-La Mancha, Albacete 02008, Spain; Viral Hepatitis Study Group, Spanish Society of Virology, Madrid, Spain
| | - Rosario Sabariegos
- Centro Regional de Investigaciones Biomédicas (CRIB), Universidad de Castilla-La Mancha, Albacete 02008, Spain; School of Medicine, Universidad de Castilla-La Mancha, Albacete 02008, Spain; Viral Hepatitis Study Group, Spanish Society of Virology, Madrid, Spain
| | - María Llanos-Valero
- Centro Regional de Investigaciones Biomédicas (CRIB), Universidad de Castilla-La Mancha, Albacete 02008, Spain
| | - Itxaso Bellón-Echeverría
- Centro Regional de Investigaciones Biomédicas (CRIB), Universidad de Castilla-La Mancha, Albacete 02008, Spain
| | - José Antonio Encinar
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche 03202, Spain
| | - Neerja Kaushik-Basu
- Department of Biochemistry and Molecular Biology, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, United States
| | - Mathy Froeyen
- Laboratory for Medicinal Chemistry, Rega Institute for Medical Research, K.U. Leuven, Belgium
| | - Antonio Mas
- Centro Regional de Investigaciones Biomédicas (CRIB), Universidad de Castilla-La Mancha, Albacete 02008, Spain; School of Pharmacy, Universidad de Castilla-La Mancha, Albacete 02008, Spain; Viral Hepatitis Study Group, Spanish Society of Virology, Madrid, Spain; Unidad de Biomedicina, CSIC-UCLM, Spain.
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14
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Cevik B. The RNA-dependent RNA polymerase of Citrus tristeza virus forms oligomers. Virology 2013; 447:121-30. [PMID: 24210106 DOI: 10.1016/j.virol.2013.08.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 06/25/2013] [Accepted: 08/23/2013] [Indexed: 11/18/2022]
Abstract
The RNA-dependent RNA polymerases (RdRp) from Citrus tristeza virus (CTV) were tagged with HA and FLAG epitopes. Differentially tagged proteins were expressed either individually or concomitantly in Escherichia coli. Immunoprecipitation of the expressed proteins with anti-FLAG antibody followed by Western blot with anti-HA antibody demonstrated that molecules of RdRp from CTV interact to form oligomers. Yeast two-hybrid assays showed that molecules of RdRp interact in eukaryotic cells. Co-immunoprecipitation with anti-FLAG antibody of truncated HA-tagged RdRps (RdRpΔ1-166-HA, RdRpΔ1-390-HA, RdRp1-169-HA) co-expressed with full-length RdRp-FLAG showed that only RdRp1-169-HA interacted with the full-length FLAG-RdRp. Yeast two-hybrid assays with truncated RdRp constructs confirmed that the oligomerization site resides in the N-terminal region and that the first 169 aa of CTV RdRp are necessary and sufficient for oligomerization both in bacterial and yeast cells. Development of control strategies targeting viral RdRp oligomer formation may inhibit virus replication and prove useful in control of CTV.
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Affiliation(s)
- Bayram Cevik
- Suleyman Demirel University, Faculty of Agriculture, Department of Plant Protection, Isparta 32260, Turkey.
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15
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Eltahla AA, Lackovic K, Marquis C, Eden JS, White PA. A fluorescence-based high-throughput screen to identify small compound inhibitors of the genotype 3a hepatitis C virus RNA polymerase. ACTA ACUST UNITED AC 2013; 18:1027-34. [PMID: 23708123 DOI: 10.1177/1087057113489883] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The hepatitis C virus (HCV) RNA-dependent RNA polymerase (RdRp) plays an essential role in the replication of HCV and is a key target for novel antiviral therapies. Several RdRp inhibitors are in clinical trials and have increased response rates when combined with current interferon-based therapies for genotype 1 (G1) HCV patients. These inhibitors, however, show poor efficacy against non-G1 genotypes, including G3a, which represents ~20% of HCV cases globally. Here, we used a commercially available fluorescent dye to characterize G3a HCV RdRp in vitro. RdRp activity was assessed via synthesis of double-stranded RNA from the single-stranded RNA poly(C) template. The assay was miniaturized to a 384-well microplate format and a pilot high-throughput screen was conducted using 10,208 "lead-like" compounds, randomly selected to identify inhibitors of HCV G3a RdRp. Of 150 compounds demonstrating greatest inhibition, 10 were confirmed using both fluorescent and radioactive assays. The top two inhibitors (HAC001 and HAC002) demonstrated specific activity, with an IC(50) of 12.7 µM and 1.0 µM, respectively. In conclusion, we describe simple, fluorescent-based high-throughput screening (HTS) for the identification of inhibitors of de novo RdRp activity, using HCV G3a RdRp as the target. The HTS system could be used against any positive-sense RNA virus that cannot be cultured.
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Affiliation(s)
- Auda A Eltahla
- 1School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, NSW, Australia
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16
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Wang J, Lyle JM, Bullitt E. Surface for catalysis by poliovirus RNA-dependent RNA polymerase. J Mol Biol 2013; 425:2529-40. [PMID: 23583774 DOI: 10.1016/j.jmb.2013.04.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 03/17/2013] [Accepted: 04/04/2013] [Indexed: 12/22/2022]
Abstract
The poliovirus RNA-dependent RNA polymerase, 3Dpol, replicates the viral genomic RNA on the surface of virus-induced intracellular membranes. Macromolecular assemblies of 3Dpol form linear arrays of subunits that propagate along a strong protein-protein interaction called interface-I, as was observed in the crystal structure of wild-type poliovirus polymerase. These "filaments" recur with slight modifications in planar sheets and, with additional modifications that accommodate curvature, in helical tubes of the polymerase, by packing filaments together via a second set of interactions. Periodic variations of subunit orientations within 3Dpol tubes give rise to "ghost reflections" in diffraction patterns computed from electron cryomicrographs of helical arrays. The ghost reflections reveal that polymerase tubes are formed by bundles of four to five interface-I filaments, which are then connected to the next bundle of filaments with a perturbation of interface interactions between bundles. While enzymatically inactive polymerase is also capable of oligomerization, much thinner tubes that lack interface-I interactions between adjacent subunits are formed, suggesting that long-range allostery produces conformational changes that extend from the active site to the protein-protein interface. Macromolecular assemblies of poliovirus polymerase show repeated use of flexible interface interactions for polymerase lattice formation, suggesting that adaptability of polymerase-polymerase interactions facilitates RNA replication. In addition, the presence of a positively charged groove identified in polymerase arrays may help position and stabilize the RNA template during replication.
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Affiliation(s)
- Jing Wang
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA
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17
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Ahn DG, Choi JK, Taylor DR, Oh JW. Biochemical characterization of a recombinant SARS coronavirus nsp12 RNA-dependent RNA polymerase capable of copying viral RNA templates. Arch Virol 2012; 157:2095-104. [PMID: 22791111 PMCID: PMC7086750 DOI: 10.1007/s00705-012-1404-x] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 05/24/2012] [Indexed: 11/26/2022]
Abstract
The severe acute respiratory syndrome coronavirus (SARS-CoV) RNA genome is replicated by a virus-encoded RNA replicase, the key component of which is the nonstructural protein 12 (nsp12). In this report, we describe the biochemical properties of a full-length recombinant SARS-CoV nsp12 RNA-dependent RNA polymerase (RdRp) capable of copying viral RNA templates. The purified SARS-CoV nsp12 showed both primer-dependent and primer-independent RNA synthesis activities using homopolymeric RNA templates. The RdRp activity was strictly dependent on Mn2+. The nsp12 preferentially copied homopolymeric pyrimidine RNA templates in the absence of an added oligonucleotide primer. It was also able to initiate de novo RNA synthesis from the 3’-ends of both the plus- and minus-strand genome of SARS-CoV, using the 3’-terminal 36- and 37-nt RNA, respectively. The in vitro RdRp assay system established with a full-length nsp12 will be useful for understanding the mechanisms of coronavirus replication and for the development of anti-SARS-CoV agents.
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Affiliation(s)
- Dae-Gyun Ahn
- Department of Biotechnology, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120-749 Korea
| | - Jin-Kyu Choi
- Department of Biotechnology, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120-749 Korea
| | - Deborah R. Taylor
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892 USA
| | - Jong-Won Oh
- Department of Biotechnology, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120-749 Korea
- Translational Research Center for Protein Function Control, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120-749 Korea
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18
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Detergent-induced activation of the hepatitis C virus genotype 1b RNA polymerase. Gene 2012; 496:79-87. [PMID: 22306265 DOI: 10.1016/j.gene.2012.01.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 12/29/2011] [Accepted: 01/18/2012] [Indexed: 11/24/2022]
Abstract
Recently, we found that sphingomyelin bound and activated hepatitis C virus (HCV) 1b RNA polymerase (RdRp), thereby recruiting the HCV replication complex into lipid raft structures. Detergents are commonly used for resolving lipids and purifying proteins, including HCV RdRp. Here, we tested the effect of detergents on HCV RdRp activity in vitro and found that non-ionic (Triton X-100, NP-40, Tween 20, Tween 80, and Brij 35) and twitterionic (CHAPS) detergents activated HCV 1b RdRps by 8-16.6 folds, but did not affect 1a or 2a RdRps. The maximum effect of these detergents was observed at around their critical micelle concentrations. On the other hand, ionic detergents (SDS and DOC) completely inactivated polymerase activity at 0.01%. In the presence of Triton X-100, HCV 1b RdRp did not form oligomers, but recruited more template RNA and increased the speed of polymerization. Comparison of polymerase and RNA-binding activity between JFH1 RdRp and Triton X-100-activated 1b RdRp indicated that monomer RdRp showed high activity because JFH1 RdRp was a monomer in physiological conditions of transcription. Besides, 502H plays a key role on oligomerization of 1b RdRp, while 2a RdRps which have the amino acid S at position 502 are monomers. This oligomer formed by 502H was disrupted both by high salt and Triton X-100. On the contrary, HCV 1b RdRp completely lost fidelity in the presence of 0.02% Triton X-100, which suggests that caution should be exercised while using Triton X-100 in anti-HCV RdRp drug screening tests.
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19
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Hillung J, Ruiz-López E, Bellón-Echeverría I, Clemente-Casares P, Mas A. Characterization of the interaction between hepatitis C virus NS5B and the human oestrogen receptor alpha. J Gen Virol 2011; 93:780-785. [PMID: 22170636 DOI: 10.1099/vir.0.039396-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The RNA-dependent RNA polymerase (NS5B) of hepatitis C virus (HCV) is part of the viral replicative complex and plays a crucial role in HCV replication. It has been described that NS5B interacts with cellular proteins, and that interactions between NS5B and host proteins are crucial for viral replication. Some of the host factors involved in the HCV replication cycle include the oestrogen receptor alpha (ESR1), protein kinases (c-Src) and chaperones (Hsp70). In this report, we determine the requirements for the interplay between NS5B and the domain C of ESR1 (ESR1C) by using Förster Resonance Energy Transfer. NS5B-ESR1C and ESR1C-ESR1C interactions are dependent on ionic strength, indicating that contacts are mainly electrostatic. Additionally, NS5B residues involved in NS5B oligomerization were also essential for NS5B-ESR1C interaction. The study of the interactions among viral and host factors will provide data to establish innovative therapeutic strategies and the development of new antiviral drugs.
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Affiliation(s)
- Julia Hillung
- Centro Regional de Investigaciones Biomédicas (CRIB), Universidad de Castilla La Mancha, 02006 Albacete, Spain
| | - Elena Ruiz-López
- Centro Regional de Investigaciones Biomédicas (CRIB), Universidad de Castilla La Mancha, 02006 Albacete, Spain
| | - Itxaso Bellón-Echeverría
- Centro Regional de Investigaciones Biomédicas (CRIB), Universidad de Castilla La Mancha, 02006 Albacete, Spain
| | - Pilar Clemente-Casares
- Centro Regional de Investigaciones Biomédicas (CRIB), Universidad de Castilla La Mancha, 02006 Albacete, Spain
| | - Antonio Mas
- Centro Regional de Investigaciones Biomédicas (CRIB), Universidad de Castilla La Mancha, 02006 Albacete, Spain
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