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Prabaharan C, Figiel M, Szczepanowski RH, Skowronek K, Zajko W, Thangaraj V, Chamera S, Nowak E, Nowotny M. Structural and biochemical characterization of cauliflower mosaic virus reverse transcriptase. J Biol Chem 2024:107555. [PMID: 39002684 DOI: 10.1016/j.jbc.2024.107555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 06/19/2024] [Accepted: 06/30/2024] [Indexed: 07/15/2024] Open
Abstract
Reverse transcriptases (RTs) are enzymes with DNA polymerase and RNase H activities. They convert single-stranded RNA into double-stranded DNA and are key enzymes for the replication of retroviruses and retroelements. Caulimoviridae is a major family of plant-infecting viruses. Caulimoviruses have a circular dsDNA genome that is replicated by reverse transcription, but in contrast to retroviruses, they lack integrase. Caulimoviruses are related to Ty3 retroelements. Ty3 RT has been extensively studied structurally and biochemically, but corresponding information for caulimoviral RTs is unavailable. In the present study, we report the first crystal structure of cauliflower mosaic virus (CaMV) RT in complex with a duplex made of RNA and DNA strands (RNA/DNA hybrid). CaMV RT forms a monomeric complex with the hybrid, unlike Ty3 RT, which does so as a dimer. Results of the RNA-dependent DNA polymerase and DNA-dependent DNA polymerase activity assays showed that individual CaMV RT molecules are able to perform full polymerase functions. However, our analyses showed that an additional CaMV RT molecule needs to transiently associate with a polymerase-competent RT molecule to execute RNase H cuts of the RNA strand. Collectively, our results provide details into the structure and function of CaMV RT and describe how the enzyme compares to other related RTs.
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Affiliation(s)
- Chandrasekaran Prabaharan
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology in Warsaw, Poland
| | - Małgorzata Figiel
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology in Warsaw, Poland
| | - Roman H Szczepanowski
- Biophysics and Bioanalytics Facility, International Institute of Molecular and Cell Biology in Warsaw, Poland
| | - Krzysztof Skowronek
- Biophysics and Bioanalytics Facility, International Institute of Molecular and Cell Biology in Warsaw, Poland
| | - Weronika Zajko
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology in Warsaw, Poland
| | | | - Sebastian Chamera
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology in Warsaw, Poland
| | - Elżbieta Nowak
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology in Warsaw, Poland.
| | - Marcin Nowotny
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology in Warsaw, Poland.
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2
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Pouresmaeil M, Azizi-Dargahlou S. Investigation of CaMV-host co-evolution through synonymous codon pattern. J Basic Microbiol 2024; 64:e2300664. [PMID: 38436477 DOI: 10.1002/jobm.202300664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 01/20/2024] [Accepted: 02/10/2024] [Indexed: 03/05/2024]
Abstract
Cauliflower mosaic virus (CaMV) has a double-stranded DNA genome and is globally distributed. The phylogeny tree of 121 CaMV isolates was categorized into two primary groups, with Iranian isolates showing the greatest genetic variations. Nucleotide A demonstrated the highest percentage (36.95%) in the CaMV genome and the dinucleotide odds ratio analysis revealed that TC dinucleotide (1.34 ≥ 1.23) and CG dinucleotide (0.63 ≤ 0.78) are overrepresented and underrepresented, respectively. Relative synonymous codon usage (RSCU) analysis confirmed codon usage bias in CaMV and its hosts. Brassica oleracea and Brassica rapa, among the susceptible hosts of CaMV, showed a codon adaptation index (CAI) value above 0.8. Additionally, relative codon deoptimization index (RCDI) results exhibited the highest degree of deoptimization in Raphanus sativus. These findings suggest that the genes of CaMV underwent codon adaptation with its hosts. Among the CaMV open reading frames (ORFs), genes that produce reverse transcriptase and virus coat proteins showed the highest CAI value of 0.83. These genes are crucial for the creation of new virion particles. The results confirm that CaMV co-evolved with its host to ensure the optimal expression of its genes in the hosts, allowing for easy infection and effective spread. To detect the force behind codon usage bias, an effective number of codons (ENC)-plot and neutrality plot were conducted. The results indicated that natural selection is the primary factor influencing CaMV codon usage bias.
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Affiliation(s)
- Mahin Pouresmaeil
- Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran
| | - Shahnam Azizi-Dargahlou
- Agricultural Biotechnology, Seed and Plant Certification and Registration Institute, Ardabil Agricultural and Natural Resources Research Center, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
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Hoffmann G, López-González S, Mahboubi A, Hanson J, Hafrén A. Cauliflower mosaic virus protein P6 is a multivalent node for RNA granule proteins and interferes with stress granule responses during plant infection. THE PLANT CELL 2023; 35:3363-3382. [PMID: 37040611 PMCID: PMC10473198 DOI: 10.1093/plcell/koad101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 03/06/2023] [Accepted: 03/22/2023] [Indexed: 06/19/2023]
Abstract
Biomolecular condensation is a multipurpose cellular process that viruses use ubiquitously during their multiplication. Cauliflower mosaic virus replication complexes are condensates that differ from those of most viruses, as they are nonmembranous assemblies that consist of RNA and protein, mainly the viral protein P6. Although these viral factories (VFs) were described half a century ago, with many observations that followed since, functional details of the condensation process and the properties and relevance of VFs have remained enigmatic. Here, we studied these issues in Arabidopsis thaliana and Nicotiana benthamiana. We observed a large dynamic mobility range of host proteins within VFs, while the viral matrix protein P6 is immobile, as it represents the central node of these condensates. We identified the stress granule (SG) nucleating factors G3BP7 and UBP1 family members as components of VFs. Similarly, as SG components localize to VFs during infection, ectopic P6 localizes to SGs and reduces their assembly after stress. Intriguingly, it appears that soluble rather than condensed P6 suppresses SG formation and mediates other essential P6 functions, suggesting that the increased condensation over the infection time-course may accompany a progressive shift in selected P6 functions. Together, this study highlights VFs as dynamic condensates and P6 as a complex modulator of SG responses.
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Affiliation(s)
- Gesa Hoffmann
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden
- Linnean Center for Plant Biology, 75007 Uppsala, Sweden
| | - Silvia López-González
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden
- Linnean Center for Plant Biology, 75007 Uppsala, Sweden
| | - Amir Mahboubi
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, 90736 Umeå, Sweden
| | - Johannes Hanson
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, 90736 Umeå, Sweden
| | - Anders Hafrén
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden
- Linnean Center for Plant Biology, 75007 Uppsala, Sweden
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Hoffmann G, Mahboubi A, Bente H, Garcia D, Hanson J, Hafrén A. Arabidopsis RNA processing body components LSM1 and DCP5 aid in the evasion of translational repression during Cauliflower mosaic virus infection. THE PLANT CELL 2022; 34:3128-3147. [PMID: 35511183 PMCID: PMC9338796 DOI: 10.1093/plcell/koac132] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 04/24/2022] [Indexed: 06/14/2023]
Abstract
Viral infections impose extraordinary RNA stress, triggering cellular RNA surveillance pathways such as RNA decapping, nonsense-mediated decay, and RNA silencing. Viruses need to maneuver among these pathways to establish infection and succeed in producing high amounts of viral proteins. Processing bodies (PBs) are integral to RNA triage in eukaryotic cells, with several distinct RNA quality control pathways converging for selective RNA regulation. In this study, we investigated the role of Arabidopsis thaliana PBs during Cauliflower mosaic virus (CaMV) infection. We found that several PB components are co-opted into viral factories that support virus multiplication. This pro-viral role was not associated with RNA decay pathways but instead, we established that PB components are helpers in viral RNA translation. While CaMV is normally resilient to RNA silencing, dysfunctions in PB components expose the virus to this pathway, which is similar to previous observations for transgenes. Transgenes, however, undergo RNA quality control-dependent RNA degradation and transcriptional silencing, whereas CaMV RNA remains stable but becomes translationally repressed through decreased ribosome association, revealing a unique dependence among PBs, RNA silencing, and translational repression. Together, our study shows that PB components are co-opted by the virus to maintain efficient translation, a mechanism not associated with canonical PB functions.
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Affiliation(s)
- Gesa Hoffmann
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala 75007, Sweden
- Linnean Center for Plant Biology, Uppsala 75007, Sweden
| | - Amir Mahboubi
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, Sweden
| | - Heinrich Bente
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala 75007, Sweden
- Linnean Center for Plant Biology, Uppsala 75007, Sweden
| | - Damien Garcia
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Johannes Hanson
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, Sweden
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Kang SH, Sun YD, Atallah OO, Huguet-Tapia JC, Noble JD, Folimonova SY. A Long Non-Coding RNA of Citrus tristeza virus: Role in the Virus Interplay with the Host Immunity. Viruses 2019; 11:E436. [PMID: 31091710 PMCID: PMC6563247 DOI: 10.3390/v11050436] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 05/08/2019] [Accepted: 05/11/2019] [Indexed: 01/01/2023] Open
Abstract
During infection, Citrus tristeza virus (CTV) produces a non-coding subgenomic RNA referred to as low-molecular-weight tristeza 1 (LMT1), which for a long time has been considered as a by-product of the complex CTV replication machinery. In this study, we investigated the role of LMT1 in the virus infection cycle using a CTV variant that does not produce LMT1 (CTV-LMT1d). We showed that lack of LMT1 did not halt virus ability to replicate or form proper virions. However, the mutant virus demonstrated significantly reduced invasiveness and systemic spread in Nicotiana benthamiana as well as an inability to establish infection in citrus. Introduction of CTV-LMT1d into the herbaceous host resulted in elevation of the levels of salicylic acid (SA) and SA-responsive pathogenesis-related genes beyond those upon inoculation with wild-type (WT) virus (CTV-WT). Further analysis showed that the LMT1 RNA produced by CTV-WT or via ectopic expression in the N. benthamiana leaves suppressed SA accumulation and up-regulated an alternative oxidase gene, which appeared to mitigate the accumulation of reactive oxygen species. To the best of our knowledge, this is the first report of a plant viral long non-coding RNA being involved in counter-acting host response by subverting the SA-mediated plant defense.
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Affiliation(s)
- Sung-Hwan Kang
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA.
| | - Yong-Duo Sun
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA.
- Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32611, USA.
| | - Osama O Atallah
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA.
| | | | - Jerald D Noble
- Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32611, USA.
| | - Svetlana Y Folimonova
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA.
- Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32611, USA.
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Geldreich A, Haas G, Kubina J, Bouton C, Tanguy M, Erhardt M, Keller M, Ryabova L, Dimitrova M. Formation of large viroplasms and virulence of Cauliflower mosaic virus in turnip plants depend on the N-terminal EKI sequence of viral protein TAV. PLoS One 2017; 12:e0189062. [PMID: 29253877 PMCID: PMC5734791 DOI: 10.1371/journal.pone.0189062] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 11/17/2017] [Indexed: 12/11/2022] Open
Abstract
Cauliflower mosaic virus (CaMV) TAV protein (TransActivator/Viroplasmin) plays a pivotal role during the infection cycle since it activates translation reinitiation of viral polycistronic RNAs and suppresses RNA silencing. It is also the major component of cytoplasmic electron-dense inclusion bodies (EDIBs) called viroplasms that are particularly evident in cells infected by the virulent CaMV Cabb B-JI isolate. These EDIBs are considered as virion factories, vehicles for CaMV intracellular movement and reservoirs for CaMV transmission by aphids. In this study, focused on different TAV mutants in vivo, we demonstrate that three physically separated domains collectively participate to the formation of large EDIBs: the N-terminal EKI motif, a sequence of the MAV domain involved in translation reinitiation and a C-terminal region encompassing the zinc finger. Surprisingly, EKI mutant TAVm3, corresponding to a substitution of the EKI motif at amino acids 11-13 by three alanines (AAA), which completely abolished the formation of large viroplasms, was not lethal for CaMV but highly reduced its virulence without affecting the rate of systemic infection. Expression of TAVm3 in a viral context led to formation of small irregularly shaped inclusion bodies, mild symptoms and low levels of viral DNA and particles accumulation, despite the production of significant amounts of mature capsid proteins. Unexpectedly, for CaMV-TAVm3 the formation of viral P2-containing electron-light inclusion body (ELIB), which is essential for CaMV aphid transmission, was also altered, thus suggesting an indirect role of the EKI tripeptide in CaMV plant-to-plant propagation. This important functional contribution of the EKI motif in CaMV biology can explain the strict conservation of this motif in the TAV sequences of all CaMV isolates.
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Affiliation(s)
- Angèle Geldreich
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Gabrielle Haas
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Julie Kubina
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Clément Bouton
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Mélanie Tanguy
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Mathieu Erhardt
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Mario Keller
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Lyubov Ryabova
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Maria Dimitrova
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
- * E-mail:
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Flobinus A, Hleibieh K, Klein E, Ratti C, Bouzoubaa S, Gilmer D. A Viral Noncoding RNA Complements a Weakened Viral RNA Silencing Suppressor and Promotes Efficient Systemic Host Infection. Viruses 2016; 8:E272. [PMID: 27782046 PMCID: PMC5086608 DOI: 10.3390/v8100272] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 09/27/2016] [Indexed: 12/24/2022] Open
Abstract
Systemic movement of beet necrotic yellow vein virus (BNYVV) in Beta macrocarpa depends on viral RNA3, whereas in Nicotiana benthamiana this RNA is dispensable. RNA3 contains a coremin motif of 20 nucleotides essential for the stabilization of noncoding RNA3 (ncRNA3) and for long-distance movement in Beta species. Coremin mutants that are unable to accumulate ncRNA3 also do not achieve systemic movement in Beta species. A mutant virus carrying a mutation in the p14 viral suppressor of RNA silencing (VSR), unable to move long distances, can be complemented with the ncRNA3 in the lesion phenotype, viral RNA accumulation, and systemic spread. Analyses of the BNYVV VSR mechanism of action led to the identification of the RNA-dependent RNA polymerase 6 (RDR6) pathway as a target of the virus VSR and the assignment of a VSR function to the ncRNA3.
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Affiliation(s)
- Alyssa Flobinus
- Institut de Biologie Moléculaire des Plantes, Integrative Virology, CNRS UPR2367, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France.
| | - Kamal Hleibieh
- Institut de Biologie Moléculaire des Plantes, Integrative Virology, CNRS UPR2367, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France.
| | - Elodie Klein
- Institut de Biologie Moléculaire des Plantes, Integrative Virology, CNRS UPR2367, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France.
- SESVanderHave, Industriepark soldatenplein, Z2nr15, Tienen B3300, Belgium.
| | - Claudio Ratti
- Dipartimento di Scienze Agrarie, Area Patologia Vegetale, Università di Bologna, Viale Fanin 40, 40127 Bologna, Italy.
| | - Salah Bouzoubaa
- Institut de Biologie Moléculaire des Plantes, Integrative Virology, CNRS UPR2367, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France.
| | - David Gilmer
- Institut de Biologie Moléculaire des Plantes, Integrative Virology, CNRS UPR2367, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France.
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Miller WA, Shen R, Staplin W, Kanodia P. Noncoding RNAs of Plant Viruses and Viroids: Sponges of Host Translation and RNA Interference Machinery. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2016; 29:156-64. [PMID: 26900786 PMCID: PMC5410770 DOI: 10.1094/mpmi-10-15-0226-fi] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Noncoding sequences in plant viral genomes are well-known to control viral replication and gene expression in cis. However, plant viral and viroid noncoding (nc)RNA sequences can also regulate gene expression acting in trans, often acting like 'sponges' that bind and sequester host cellular machinery to favor viral infection. Noncoding sequences of small subgenomic (sg)RNAs of Barley yellow dwarf virus (BYDV) and Red clover necrotic mosaic virus (RCNMV) contain a cap-independent translation element that binds translation initiation factor eIF4G. We provide new evidence that a sgRNA of BYDV can globally attenuate host translation, probably by sponging eIF4G. Subgenomic ncRNA of RCNMV is generated via 5' to 3' degradation by a host exonuclease. The similar noncoding subgenomic flavivirus (sf)RNA, inhibits the innate immune response, enhancing viral pathogenesis. Cauliflower mosaic virus transcribes massive amounts of a 600-nt ncRNA, which is processed into small RNAs that overwhelm the host's RNA interference (RNAi) system. Viroids use the host RNAi machinery to generate viroid-derived ncRNAs that inhibit expression of host defense genes by mimicking a microRNA. More examples of plant viral and viroid ncRNAs are likely to be discovered, revealing fascinating new weaponry in the host-virus arms race.
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Affiliation(s)
- W. Allen Miller
- Interdepartmental Genetics & Genomics Program, Iowa State University, Ames, IA 50011 USA
- Corresponding author:
| | - Ruizhong Shen
- Interdepartmental Genetics & Genomics Program, Iowa State University, Ames, IA 50011 USA
| | | | - Pulkit Kanodia
- Interdepartmental Genetics & Genomics Program, Iowa State University, Ames, IA 50011 USA
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