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Sobczak JM, Barkovska I, Balke I, Rothen DA, Mohsen MO, Skrastina D, Ogrina A, Martina B, Jansons J, Bogans J, Vogel M, Bachmann MF, Zeltins A. Identifying Key Drivers of Efficient B Cell Responses: On the Role of T Help, Antigen-Organization, and Toll-like Receptor Stimulation for Generating a Neutralizing Anti-Dengue Virus Response. Vaccines (Basel) 2024; 12:661. [PMID: 38932390 PMCID: PMC11209419 DOI: 10.3390/vaccines12060661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/14/2024] [Accepted: 05/23/2024] [Indexed: 06/28/2024] Open
Abstract
T help (Th), stimulation of toll-like receptors (pathogen-associated molecular patterns, PAMPs), and antigen organization and repetitiveness (pathogen-associated structural patterns, PASPs) were shown numerous times to be important in driving B-cell and antibody responses. In this study, we dissected the individual contributions of these parameters using newly developed "Immune-tag" technology. As model antigens, we used eGFP and the third domain of the dengue virus 1 envelope protein (DV1 EDIII), the major target of virus-neutralizing antibodies. The respective proteins were expressed alone or genetically fused to the N-terminal fragment of the cucumber mosaic virus (CMV) capsid protein-nCMV, rendering the antigens oligomeric. In a step-by-step manner, RNA was attached as a PAMP, and/or a universal Th-cell epitope was genetically added for additional Th. Finally, a PASP was added to the constructs by displaying the antigens highly organized and repetitively on the surface of CMV-derived virus-like particles (CuMV VLPs). Sera from immunized mice demonstrated that each component contributed stepwise to the immunogenicity of both proteins. All components combined in the CuMV VLP platform induced by far the highest antibody responses. In addition, the DV1 EDIII induced high levels of DENV-1-neutralizing antibodies only if displayed on VLPs. Thus, combining multiple cues typically associated with viruses results in optimal antibody responses.
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Affiliation(s)
- Jan M. Sobczak
- Department of Immunology, University Clinic of Rheumatology and Immunology, Inselspital, CH-3010 Bern, Switzerland; (D.A.R.); (M.O.M.); (M.V.); (M.F.B.)
- Department of BioMedical Research, University of Bern, CH-3008 Bern, Switzerland
| | - Irena Barkovska
- Latvian Biomedical Research and Study Centre, LV-1067 Riga, Latvia; (I.B.); (I.B.); (D.S.); (A.O.); (J.J.); (J.B.); (A.Z.)
| | - Ina Balke
- Latvian Biomedical Research and Study Centre, LV-1067 Riga, Latvia; (I.B.); (I.B.); (D.S.); (A.O.); (J.J.); (J.B.); (A.Z.)
| | - Dominik A. Rothen
- Department of Immunology, University Clinic of Rheumatology and Immunology, Inselspital, CH-3010 Bern, Switzerland; (D.A.R.); (M.O.M.); (M.V.); (M.F.B.)
- Department of BioMedical Research, University of Bern, CH-3008 Bern, Switzerland
| | - Mona O. Mohsen
- Department of Immunology, University Clinic of Rheumatology and Immunology, Inselspital, CH-3010 Bern, Switzerland; (D.A.R.); (M.O.M.); (M.V.); (M.F.B.)
- Department of BioMedical Research, University of Bern, CH-3008 Bern, Switzerland
| | - Dace Skrastina
- Latvian Biomedical Research and Study Centre, LV-1067 Riga, Latvia; (I.B.); (I.B.); (D.S.); (A.O.); (J.J.); (J.B.); (A.Z.)
| | - Anete Ogrina
- Latvian Biomedical Research and Study Centre, LV-1067 Riga, Latvia; (I.B.); (I.B.); (D.S.); (A.O.); (J.J.); (J.B.); (A.Z.)
| | - Byron Martina
- Artemis Bioservices, 2629 JD Delft, The Netherlands;
- Protinhi Therapeutics, 6534 AT Nijmegen, The Netherlands
| | - Juris Jansons
- Latvian Biomedical Research and Study Centre, LV-1067 Riga, Latvia; (I.B.); (I.B.); (D.S.); (A.O.); (J.J.); (J.B.); (A.Z.)
| | - Janis Bogans
- Latvian Biomedical Research and Study Centre, LV-1067 Riga, Latvia; (I.B.); (I.B.); (D.S.); (A.O.); (J.J.); (J.B.); (A.Z.)
| | - Monique Vogel
- Department of Immunology, University Clinic of Rheumatology and Immunology, Inselspital, CH-3010 Bern, Switzerland; (D.A.R.); (M.O.M.); (M.V.); (M.F.B.)
- Department of BioMedical Research, University of Bern, CH-3008 Bern, Switzerland
| | - Martin F. Bachmann
- Department of Immunology, University Clinic of Rheumatology and Immunology, Inselspital, CH-3010 Bern, Switzerland; (D.A.R.); (M.O.M.); (M.V.); (M.F.B.)
- Department of BioMedical Research, University of Bern, CH-3008 Bern, Switzerland
- Nuffield Department of Medicine, The Jenner Institute, University of Oxford, Oxford OX3 7BN, UK
| | - Andris Zeltins
- Latvian Biomedical Research and Study Centre, LV-1067 Riga, Latvia; (I.B.); (I.B.); (D.S.); (A.O.); (J.J.); (J.B.); (A.Z.)
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Balke I, Silamikelis I, Radovica-Spalvina I, Zeltina V, Resevica G, Fridmanis D, Zeltins A. Ryegrass mottle virus complete genome determination and development of infectious cDNA by combining two methods- 3' RACE and RNA-Seq. PLoS One 2023; 18:e0287278. [PMID: 38051715 DOI: 10.1371/journal.pone.0287278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 11/21/2023] [Indexed: 12/07/2023] Open
Abstract
Ryegrass mottle virus (RGMoV; genus: Sobemovirus) is a single-stranded positive RNA virus with a 30 nm viral particle size. It exhibits T = 3 symmetry with 180 coat protein (CP) subunits forming a viral structure. The RGMoV genome comprises five open reading frames that encode P1, Px, a membrane-anchored 3C-like serine protease, a viral genome-linked protein, P16, an RNA-dependent RNA polymerase, and CP. The RGMoV genome size varies, ranging from 4175 nt (MW411579.1) to 4253 nt (MW411579.1) in the deposited sequences. An earlier deposited RGMoV complete genome sequence of 4212 nt length (EF091714.1) was used to develop an infectious complementary DNA (icDNA) construct for in vitro gRNA transcription from the T7 promoter. However, viral infection was not induced when the transcribed gRNA was introduced into oat plants, indicating the potential absence of certain sequences in either the 5' or 3' untranslated regions (UTR) or both. The complete sequence of the 3' UTR was determined through 3' end RACE, while the 5' UTR was identified using high-throughput sequencing (HTS)-RNA-Seq to resolve the potential absences. Only the icDNA vector containing the newly identified UTR sequences proved infectious, resulting in typical viral infection symptoms and subsequent propagation of progeny viruses, exhibiting the ability to cause repeated infections in oat plants after at least one passage. The successful generation of icDNA highlighted the synergistic potential of utilizing both methods when a single approach failed. Furthermore, this study demonstrated the reliability of HTS as a method for determining the complete genome sequence of viral genomes.
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Affiliation(s)
- Ina Balke
- Plant Virus Protein Research Group, Latvian Biomedical Research and Study Centre, Riga, Latvia
| | - Ivars Silamikelis
- Bioinformatics Core Facility, Latvian Biomedical Research and Study Centre, Riga, Latvia
| | - Ilze Radovica-Spalvina
- Genome Centre, Genotyping and Sequencing Unit, Latvian Biomedical Research and Study Centre, Riga, Latvia
| | - Vilija Zeltina
- Plant Virology Group, Latvian Biomedical Research and Study Centre, Riga, Latvia
| | - Gunta Resevica
- Plant Virology Group, Latvian Biomedical Research and Study Centre, Riga, Latvia
| | - Davids Fridmanis
- "Exotic" Site Microbiome and G-Protein Coupled Receptor Functional Research Group, Latvian Biomedical Research and Study Centre, Riga, Latvia
| | - Andris Zeltins
- Plant Virology Group, Latvian Biomedical Research and Study Centre, Riga, Latvia
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VPg Impact on Ryegrass Mottle Virus Serine-like 3C Protease Proteolysis and Structure. Int J Mol Sci 2023; 24:ijms24065347. [PMID: 36982419 PMCID: PMC10048871 DOI: 10.3390/ijms24065347] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/03/2023] [Accepted: 03/09/2023] [Indexed: 03/16/2023] Open
Abstract
Sobemoviruses encode serine-like 3C proteases (Pro) that participate in the processing and maturation of other virus-encoded proteins. Its cis and trans activity is mediated by the naturally unfolded virus-genome-linked protein (VPg). Nuclear magnetic resonance studies show a Pro–VPg complex interaction and VPg tertiary structure; however, information regarding structural changes of the Pro–VPg complex during interaction is lacking. Here, we solved a full Pro–VPg 3D structure of ryegrass mottle virus (RGMoV) that demonstrates the structural changes in three different conformations due to VPg interaction with Pro. We identified a unique site of VPg interaction with Pro that was not observed in other sobemoviruses, and observed different conformations of the Pro β2 barrel. This is the first report of a full plant Pro crystal structure with its VPg cofactor. We also confirmed the existence of an unusual previously unmapped cleavage site for sobemovirus Pro in the transmembrane domain: E/A. We demonstrated that RGMoV Pro in cis activity is not regulated by VPg and that in trans, VPg can also mediate Pro in free form. Additionally, we observed Ca2+ and Zn2+ inhibitory effects on the Pro cleavage activity.
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Gnanasekaran P, Gupta N, Ponnusamy K, Chakraborty S. Geminivirus Betasatellite-Encoded βC1 Protein Exhibits Novel ATP Hydrolysis Activity That Influences Its DNA-Binding Activity and Viral Pathogenesis. J Virol 2021; 95:e0047521. [PMID: 34132576 PMCID: PMC8354231 DOI: 10.1128/jvi.00475-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 06/09/2021] [Indexed: 11/20/2022] Open
Abstract
Plant virus satellites are maintained by their associated helper viruses, and satellites influence viral pathogenesis. Diseases caused by geminivirus-betasatellite complexes can become epidemics and therefore have become a threat to economically important crops across the world. Here, we identified a novel molecular function of the betasatellite-encoded pathogenicity determinant βC1. The tomato leaf curl Patna betasatellite (ToLCPaB)-encoded βC1 protein was found to exhibit novel ATPase activity in the presence of the divalent metal ion cofactor MgCl2. Moreover, ATPase activity was confirmed to be ubiquitously displayed by βC1 proteins encoded by diverse betasatellites. Mutational and sequence analysis showed that conserved lysine/arginine residues at positions 49/50 and 91 of βC1 proteins are essential for their ATPase activity. Biochemical studies revealed that the DNA-binding activity of the βC1 protein was interfered with by the binding of ATP to the protein. Mutating arginine 91 of βC1 to alanine reduced its DNA-binding activity. The results of docking studies provided evidence for an overlap of the ATP-binding and DNA-binding regions of βC1 and for the importance of arginine 91 for both ATP-binding and DNA-binding activities. A mutant betasatellite with a specifically βC1-ATPase dominant negative mutation was found to induce symptoms on Nicotiana benthamiana plants similar to those induced by wild-type betasatellite infection. The ATPase function of βC1 was found to be negatively associated with geminivirus-betasatellite DNA accumulation, despite the positive influence of this ATPase function on the accumulation of replication-associated protein (Rep) and βC1 transcripts. IMPORTANCE Most satellites influence the pathogenesis of their helper viruses. Here, we characterized the novel molecular function of βC1, a nonstructural pathogenicity determinant protein encoded by a betasatellite. We demonstrated the display of ATPase activity by this βC1 protein. Additionally, we confirmed the ubiquitous display of ATPase activity by βC1 proteins encoded by diverse betasatellites. The lysine/arginine residues conserved at positions 49 and 91 of βC1 were found to be crucial for its ATPase function. DNA-binding activity of βC1 was found to be reduced in the presence of ATP. Inhibition of ATPase activity of βC1 in the presence of an excess concentration of cold ATP, GTP, CTP, or UTP suggested that the purified βC1 can also hydrolyze other cellular nucleoside triphosphates (NTPs) besides ATP in vitro. These results established the importance of the ATPase and DNA-binding activities of the βC1 protein in regulating geminivirus-betasatellite DNA accumulation in the infected plant cell.
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Affiliation(s)
- Prabu Gnanasekaran
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru Universitygrid.10706.30, New Delhi, India
| | - Neha Gupta
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru Universitygrid.10706.30, New Delhi, India
| | | | - Supriya Chakraborty
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru Universitygrid.10706.30, New Delhi, India
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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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Rodamilans B, Shan H, Pasin F, García JA. Plant Viral Proteases: Beyond the Role of Peptide Cutters. FRONTIERS IN PLANT SCIENCE 2018; 9:666. [PMID: 29868107 PMCID: PMC5967125 DOI: 10.3389/fpls.2018.00666] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/30/2018] [Indexed: 05/23/2023]
Abstract
Almost half of known plant viral species rely on proteolytic cleavages as key co- and post-translational modifications throughout their infection cycle. Most of these viruses encode their own endopeptidases, proteases with high substrate specificity that internally cleave large polyprotein precursors for the release of functional sub-units. Processing of the polyprotein, however, is not an all-or-nothing process in which endopeptidases act as simple peptide cutters. On the contrary, spatial-temporal modulation of these polyprotein cleavage events is crucial for a successful viral infection. In this way, the processing of the polyprotein coordinates viral replication, assembly and movement, and has significant impact on pathogen fitness and virulence. In this mini-review, we give an overview of plant viral proteases emphasizing their importance during viral infections and the varied functionalities that result from their proteolytic activities.
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Affiliation(s)
- Bernardo Rodamilans
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - Hongying Shan
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - Fabio Pasin
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan
| | - Juan Antonio García
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
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Complete nucleotide sequence of Solanum nodiflorum mottle virus. Arch Virol 2017; 162:1731-1736. [DOI: 10.1007/s00705-017-3273-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 02/01/2017] [Indexed: 10/20/2022]
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Structural studies on chimeric Sesbania mosaic virus coat protein: Revisiting SeMV assembly. Virology 2016; 489:34-43. [DOI: 10.1016/j.virol.2015.11.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 11/27/2015] [Accepted: 11/28/2015] [Indexed: 01/25/2023]
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Sõmera M, Sarmiento C, Truve E. Overview on Sobemoviruses and a Proposal for the Creation of the Family Sobemoviridae. Viruses 2015; 7:3076-115. [PMID: 26083319 PMCID: PMC4488728 DOI: 10.3390/v7062761] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 05/18/2015] [Accepted: 06/02/2015] [Indexed: 12/26/2022] Open
Abstract
The genus Sobemovirus, unassigned to any family, consists of viruses with single-stranded plus-oriented single-component RNA genomes and small icosahedral particles. Currently, 14 species within the genus have been recognized by the International Committee on Taxonomy of Viruses (ICTV) but several new species are to be recognized in the near future. Sobemovirus genomes are compact with a conserved structure of open reading frames and with short untranslated regions. Several sobemoviruses are important pathogens. Moreover, over the last decade sobemoviruses have become important model systems to study plant virus evolution. In the current review we give an overview of the structure and expression of sobemovirus genomes, processing and functions of individual proteins, particle structure, pathology and phylogenesis of sobemoviruses as well as of satellite RNAs present together with these viruses. Based on a phylogenetic analysis we propose that a new family Sobemoviridae should be recognized including the genera Sobemovirus and Polemovirus. Finally, we outline the future perspectives and needs for the research focusing on sobemoviruses.
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Affiliation(s)
- Merike Sõmera
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia.
| | - Cecilia Sarmiento
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia.
| | - Erkki Truve
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia.
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Sõmera M, Truve E. Rottboellia yellow mottle virus is a distinct species within the genus Sobemovirus. Arch Virol 2015; 160:857-63. [PMID: 25613163 DOI: 10.1007/s00705-015-2336-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 01/08/2015] [Indexed: 11/28/2022]
Abstract
Once considered a tentative member of the genus Sobemovirus, rottboellia yellow mottle virus (RoMoV) was excluded from the latest species list of the ICTV after the discovery of imperata yellow mottle virus (IYMV), which resembles RoMoV in host range and geographic origin. Here, sequence analysis of the complete genome of RoMoV suggested that it should be considered a distinct species within the genus Sobemovirus. It has the highest sequence identity (55 %) to ryegrass mottle virus (RGMoV), whereas its sequence identity to IYMV is lower (44 %). In a phylogenetic tree, RoMoV clusters together with RGMoV and artemisia virus A (ArtVA), a dicot-infecting sobemovirus.
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Affiliation(s)
- Merike Sõmera
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618, Tallinn, Estonia,
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Govind K, Bakshi A, Savithri HS. Interaction of Sesbania mosaic virus (SeMV) RNA-dependent RNA polymerase (RdRp) with the p10 domain of polyprotein 2a and its implications in SeMV replication. FEBS Open Bio 2014; 4:362-9. [PMID: 24918050 PMCID: PMC4050190 DOI: 10.1016/j.fob.2014.03.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 03/19/2014] [Accepted: 03/19/2014] [Indexed: 01/10/2023] Open
Abstract
SeMV RdRp strongly interacts with p10 domain of polyprotein 2a. C-terminal disordered domain of RdRp is required for interaction with p10. p10 acts as a positive regulator of RdRp activity.
Identification of viral encoded proteins that interact with RNA-dependent RNA polymerase (RdRp) is an important step towards unraveling the mechanism of replication. Sesbania mosaic virus (SeMV) RdRp was shown to interact strongly with p10 domain of polyprotein 2a and moderately with the protease domain. Mutational analysis suggested that the C-terminal disordered domain of RdRp is involved in the interaction with p10. Coexpression of full length RdRp and p10 resulted in formation of RdRp–p10 complex which showed significantly higher polymerase activity than RdRp alone. Interestingly, CΔ43 RdRp also showed a similar increase in activity. Thus, p10 acts as a positive regulator of RdRp by interacting with the C-terminal disordered domain of RdRp.
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Key Words
- 3AT, 3 amino-1,2,4 triazol
- CP, coat protein
- IPTG, isopropyl-1thio-β-d-galactopyranoside
- LB, Luria Bertani broth
- LacZ, β-galactosidase
- MEL1, α-galactosidase
- MP, movement protein
- Ni–NTA, nickel–nitrilo tri-acetic acid
- ONPG, ortho-nitrophenyl-β-galactoside
- PBST, phosphate buffered saline with 0.1% TWEEN 20
- Pro, protease
- Protein-protein interactions
- RNA-dependent RNA polymerase (RdRp)
- RdRp, RNA-dependent RNA polymerase
- Replication
- SD, synthetic dropout
- SeMV, Sesbania mosaic virus
- Sesbania mosaic virus
- Sobemovirus
- VPg, viral protein genome linked
- Y2H, yeast two hybrid
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Affiliation(s)
- Kunduri Govind
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Arindam Bakshi
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
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Poulicard N, Pinel-Galzi A, Fargette D, Hébrard E. Alternative mutational pathways, outside the VPg, of rice yellow mottle virus to overcome eIF(iso)4G-mediated rice resistance under strong genetic constraints. J Gen Virol 2013; 95:219-224. [PMID: 24141250 DOI: 10.1099/vir.0.057810-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The adaptation of rice yellow mottle virus (RYMV) to rymv1-mediated resistance has been reported to involve mutations in the viral genome-linked protein (VPg). In this study, we analysed several cases of rymv1-2 resistance breakdown by an isolate with low adaptability. Surprisingly, in these rarely occurring resistance-breaking (RB) genotypes, mutations were detected outside the VPg, in the ORF2a/ORF2b overlapping region. The causal role of three mutations associated with rymv1-2 resistance breakdown was validated via directed mutagenesis of an infectious clone. In resistant plants, these mutations increased viral accumulation as efficiently as suboptimal RB mutations in the VPg. Interestingly, these mutations are located in a highly conserved, but unfolded, domain. Altogether, our results indicate that under strong genetic constraints, a priori unfit genotypes can follow alternative mutational pathways, i.e. outside the VPg, to overcome rymv1-2 resistance.
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Affiliation(s)
- Nils Poulicard
- Institut de Recherche pour le Développement (IRD), UMR RPB, Montpellier, France
| | - Agnès Pinel-Galzi
- Institut de Recherche pour le Développement (IRD), UMR RPB, Montpellier, France
| | - Denis Fargette
- Institut de Recherche pour le Développement (IRD), UMR RPB, Montpellier, France
| | - Eugénie Hébrard
- Institut de Recherche pour le Développement (IRD), UMR RPB, Montpellier, France
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13
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Guha D, Poornima Priyadarshini C, Purakayastha A, Thippeswamy R, Lakshmikanth M, Savithri H. Biochemical characterization of C4 protein of Cotton Leaf Curl Kokhran Virus-Dabawali. Biochim Biophys Acta Gen Subj 2013; 1830:3734-44. [DOI: 10.1016/j.bbagen.2013.02.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 02/10/2013] [Accepted: 02/27/2013] [Indexed: 10/27/2022]
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Mathur C, Savithri HS. Novel ATPase activity of the polyprotein intermediate, Viral Protein genome-linked-Nuclear Inclusion-a protease, of Pepper vein banding potyvirus. Biochem Biophys Res Commun 2012; 427:113-8. [DOI: 10.1016/j.bbrc.2012.09.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 09/06/2012] [Indexed: 10/27/2022]
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15
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Govind K, Mäkinen K, Savithri HS. Sesbania mosaic virus (SeMV) infectious clone: possible mechanism of 3' and 5' end repair and role of polyprotein processing in viral replication. PLoS One 2012; 7:e31190. [PMID: 22355344 PMCID: PMC3280281 DOI: 10.1371/journal.pone.0031190] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 01/04/2012] [Indexed: 11/19/2022] Open
Abstract
Sesbania mosaic virus (SeMV) is a positive stranded RNA virus belonging to the genus Sobemovirus. Construction of an infectious clone is an essential step for deciphering the virus gene functions in vivo. Using Agrobacterium based transient expression system we show that SeMV icDNA is infectious on Sesbania grandiflora and Cyamopsis tetragonoloba plants. The efficiency of icDNA infection was found to be significantly high on Cyamopsis plants when compared to that on Sesbania grandiflora. The coat protein could be detected within 6 days post infiltration in the infiltrated leaves. Different species of viral RNA (double stranded and single stranded genomic and subgenomic RNA) could be detected upon northern analysis, suggesting that complete replication had taken place. Based on the analysis of the sequences at the genomic termini of progeny RNA from SeMV icDNA infiltrated leaves and those of its 3' and 5' terminal deletion mutants, we propose a possible mechanism for 3' and 5' end repair in vivo. Mutation of the cleavage sites in the polyproteins encoded by ORF 2 resulted in complete loss of infection by the icDNA, suggesting the importance of correct polyprotein processing at all the four cleavage sites for viral replication. Complementation analysis suggested that ORF 2 gene products can act in trans. However, the trans acting ability of ORF 2 gene products was abolished upon deletion of the N-terminal hydrophobic domain of polyprotein 2a and 2ab, suggesting that these products necessarily function at the replication site, where they are anchored to membranes.
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Affiliation(s)
- Kunduri Govind
- Indian Institute of Science, Bangalore, Karnataka, India
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Roy Chowdhury S, Savithri HS. Interaction of Sesbania mosaic virus movement protein with VPg and P10: implication to specificity of genome recognition. PLoS One 2011; 6:e15609. [PMID: 21246040 PMCID: PMC3016346 DOI: 10.1371/journal.pone.0015609] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 11/17/2010] [Indexed: 11/18/2022] Open
Abstract
Sesbania mosaic virus (SeMV) is a single strand positive-sense RNA plant virus that belongs to the genus Sobemovirus. The mechanism of cell-to-cell movement in sobemoviruses has not been well studied. With a view to identify the viral encoded ancillary proteins of SeMV that may assist in cell-to-cell movement of the virus, all the proteins encoded by SeMV genome were cloned into yeast Matchmaker system 3 and interaction studies were performed. Two proteins namely, viral protein genome linked (VPg) and a 10-kDa protein (P10) c v gft encoded by OFR 2a, were identified as possible interacting partners in addition to the viral coat protein (CP). Further characterization of these interactions revealed that the movement protein (MP) recognizes cognate RNA through interaction with VPg, which is covalently linked to the 5' end of the RNA. Analysis of the deletion mutants delineated the domains of MP involved in the interaction with VPg and P10. This study implicates for the first time that VPg might play an important role in specific recognition of viral genome by MP in SeMV and shed light on the possible role of P10 in the viral movement.
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