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Dufresne PJ, Ubalijoro E, Fortin MG, Laliberté JF. Arabidopsis thaliana class II poly(A)-binding proteins are required for efficient multiplication of turnip mosaic virus. J Gen Virol 2008; 89:2339-2348. [PMID: 18753244 DOI: 10.1099/vir.0.2008/002139-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The poly(A)-binding protein (PABP) is an important translation initiation factor that binds to the polyadenylated 3' end of mRNA. We have previously shown that PABP2 interacts with the RNA-dependent RNA polymerase (RdRp) and VPg-Pro of turnip mosaic virus (TuMV) within virus-induced vesicles. At least eight PABP isoforms are produced in Arabidopsis thaliana, three of which (PABP2, PABP4 and PABP8) are highly and broadly expressed and probably constitute the bulk of PABP required for cellular functions. Upon TuMV infection, an increase in protein and mRNA expression from PAB2, PAB4 and PAB8 genes was recorded. In vitro binding assays revealed that RdRp and the viral genome-linked protein (VPg-Pro) interact preferentially with PABP2 but are also capable of interaction with one or both of the other class II PABPs (i.e. PABP4 and PABP8). To assess whether PABP is required for potyvirus replication, A. thaliana single and double pab knockouts were isolated and inoculated with TuMV. All lines showed susceptibility to TuMV. However, when precise monitoring of viral RNA accumulation was performed, it was found to be reduced by 2.2- and 3.5-fold in pab2 pab4 and pab2 pab8 mutants, respectively, when compared with wild-type plants. PABP levels were most significantly reduced in the membrane-associated fraction in both of these mutants. TuMV mRNA levels thus correlated with cellular PABP concentrations in these A. thaliana knockout lines. These data provide further support for a role of PABP in potyvirus replication.
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Affiliation(s)
- Philippe J Dufresne
- Department of Plant Science, McGill University, Ste-Anne-de-Bellevue, Québec H9X 3V9, Canada
| | - Eliane Ubalijoro
- Department of Plant Science, McGill University, Ste-Anne-de-Bellevue, Québec H9X 3V9, Canada
| | - Marc G Fortin
- Department of Plant Science, McGill University, Ste-Anne-de-Bellevue, Québec H9X 3V9, Canada
| | - Jean-François Laliberté
- Institut national de la recherche scientifique, Institut Armand-Frappier, Laval, Québec H7V 1B7, Canada
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Hafrén A, Mäkinen K. Purification of viral genome-linked protein VPg from potato virus A-infected plants reveals several post-translationally modified forms of the protein. J Gen Virol 2008; 89:1509-1518. [PMID: 18474568 DOI: 10.1099/vir.0.83649-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In order to be able to analyse post-translational modifications and protein interactions of viral genome-linked protein VPg taking place during potato virus A (PVA) infection, an affinity tag-based purification system was developed by inserting a sequence encoding a six-histidine and haemagglutinin (HisHA) tag to the 3' end of the VPg coding sequence within the infectious cDNA clone of PVA. The engineered virus was fully functional and the HisHA tag-encoding sequence remained stable in the PVA genome throughout the infection process. Purification under denaturing conditions resulted in a protein sample that contained multiple VPg and NIa forms carrying post-translational modifications that altered their isoelectric points. Non-modified tagged VPg (pI 8) was a minor product in the protein sample derived from total leaf proteins, but when the replication-associated membranes were used as starting material, its relative amount increased. Further characterization demonstrated that some of the PVA VPg isoforms were modified by multiple phosphorylation events. Purity of the proteins derived from the native purifications with either of the tags was evaluated. A clearly purer VPg sample was obtained by performing tandem affinity purification utilizing both tags sequentially. NIb, CI and HC-Pro co-purified in an affinity-tagged VPg-dependent manner, indicating that the system was able to isolate protein complexes operating during PVA infection.
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Affiliation(s)
- Anders Hafrén
- Department of Applied Chemistry and Microbiology, Latokartanonkaari 11, PO Box 27, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Kristiina Mäkinen
- Department of Applied Chemistry and Microbiology, Latokartanonkaari 11, PO Box 27, University of Helsinki, FIN-00014 Helsinki, Finland
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Beauchemin C, Laliberté JF. The poly(A) binding protein is internalized in virus-induced vesicles or redistributed to the nucleolus during turnip mosaic virus infection. J Virol 2007; 81:10905-13. [PMID: 17670821 PMCID: PMC2045535 DOI: 10.1128/jvi.01243-07] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Poly(A) binding protein 2 (PABP2) of Arabidopsis thaliana was previously shown to interact with VPg-Pro of turnip mosaic virus (TuMV) and may consequently play an important role during infection. Subcellular fractionation experiments revealed that PABP2 was predominantly a cytoplasmic soluble protein in healthy plants. However, in TuMV-infected plants, a subpopulation of PABP2 was membrane associated or was localized in the nucleus. Confocal microscopy experiments indicated that PABP2 was partially retargeted to the nucleolus in the presence of TuMV VPg-Pro. In addition, the membrane association of PABP2 during TuMV infection resulted from the internalization of the host protein in 6K-VPg-Pro-induced vesicles, as shown by a combination of confocal microscopy and sucrose gradient fractionation experiments. This redistribution of an important translation initiation factor to the nucleolus and to membrane structure likely underlies two important processes of the TuMV replication cycle.
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Affiliation(s)
- Chantal Beauchemin
- INRS-Institut Armand Frappier, 531 Boulevard des Prairies, Laval, Québec H7V 1B7, Canada
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Cotton S, Dufresne PJ, Thivierge K, Ide C, Fortin MG. The VPgPro protein of Turnip mosaic virus: in vitro inhibition of translation from a ribonuclease activity. Virology 2006; 351:92-100. [PMID: 16647732 PMCID: PMC7172391 DOI: 10.1016/j.virol.2006.03.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Revised: 02/06/2006] [Accepted: 03/14/2006] [Indexed: 02/06/2023]
Abstract
A role for viral encoded genome-linked (VPg) proteins in translation has often been suggested because of their covalent attachment to the 5′ end of the viral RNA, reminiscent of the cap structure normally present on most eukaryotic mRNAs. We tested the effect of Turnip mosaic virus (TuMV) VPgPro on translation of reporter RNAs in in vitro translation systems. The presence of VPgPro in either wheat germ extract or rabbit reticulocyte lysate systems lead to inhibition of translation. The inhibition did not appear to be mediated by the interaction of VPg with the eIF(iso)4E translation initiation factor since a VPg mutant that does not interact with eIF(iso)4E still inhibited translation. Monitoring the fate of RNAs revealed that they were degraded as a result of addition of TuMV VPgPro or of Norwalk virus (NV) VPg protein. The RNA degradation was not the result of translation being arrested and was heat labile and partially EDTA sensitive. The capacity of TuMV VPgPro and of (NV) VPg to degrade RNA suggests that these proteins have a ribonucleolytic activity which may contribute to the host RNA translation shutoff associated with many virus infections.
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Affiliation(s)
- Sophie Cotton
- Department of Plant Science, McGill University, 21,111 Lakeshore, Ste-Anne-de-Bellevue, Québec, Canada H9X 3V9
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Léonard S, Viel C, Beauchemin C, Daigneault N, Fortin MG, Laliberté JF. Interaction of VPg-Pro of turnip mosaic virus with the translation initiation factor 4E and the poly(A)-binding protein in planta. J Gen Virol 2004; 85:1055-1063. [PMID: 15039548 DOI: 10.1099/vir.0.19706-0] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The viral protein linked to the genome (VPg) of Turnip mosaic virus (TuMV) interacts in vitro with the translation eukaryotic initiation factor (eIF) 4E. In the present study, we investigated the consequence of TuMV infection on eIF4E expression. Two isomers are present in plants, namely eIF4E and eIF(iso)4E. Expression of the latter was detected in both TuMV-infected and mock-inoculated Brassica perviridis plants, but expression of eIF4E was found only in infected plants. Membranes from TuMV-infected or mock-inoculated tissues were separated by sucrose gradient centrifugation and fractions were collected. Immunoblot analyses showed that 6K(2)-VPg-Pro/VPg-Pro polyproteins were associated with endoplasmic reticulum membranes and were the viral forms likely to interact with eIF(iso)4E and eIF4E. In planta interaction between 6K(2)-VPg-Pro/VPg-Pro and eIF(iso)4E/eIF4E was confirmed by co-purification by metal chelation chromatography. The poly(A)-binding protein (PABP) was also found to co-purify with VPg-Pro. Direct interaction between VPg-Pro and PABP was shown by an ELISA-based binding assay. These experiments suggest that a multi-protein complex may form around VPg-Pro of TuMV.
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Affiliation(s)
- Simon Léonard
- Institut National de la Recherche Scientifique, Institut Armand-Frappier, 531 boulevard des Prairies, Laval, Québec, Canada H7V 1B7
| | - Catherine Viel
- Institut National de la Recherche Scientifique, Institut Armand-Frappier, 531 boulevard des Prairies, Laval, Québec, Canada H7V 1B7
| | - Chantal Beauchemin
- Institut National de la Recherche Scientifique, Institut Armand-Frappier, 531 boulevard des Prairies, Laval, Québec, Canada H7V 1B7
| | - Nicole Daigneault
- Institut National de la Recherche Scientifique, Institut Armand-Frappier, 531 boulevard des Prairies, Laval, Québec, Canada H7V 1B7
| | - Marc G Fortin
- Department of Plant Science, McGill University, 21 111 Lakeshore, Ste-Anne-de-Bellevue, Québec, Canada H9X 3V9
| | - Jean-François Laliberté
- Institut National de la Recherche Scientifique, Institut Armand-Frappier, 531 boulevard des Prairies, Laval, Québec, Canada H7V 1B7
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Chisholm J, Wieczorek A, Sanfaçon H. Expression and partial purification of recombinant tomato ringspot nepovirus 3C-like proteinase: comparison of the activity of the mature proteinase and the VPg-proteinase precursor. Virus Res 2001; 79:153-64. [PMID: 11551656 PMCID: PMC7172257 DOI: 10.1016/s0168-1702(01)00344-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2001] [Revised: 06/20/2001] [Accepted: 06/20/2001] [Indexed: 11/28/2022]
Abstract
The 3C-like proteinase (Pro) from Tomato ringspot virus (genus Nepovirus) is responsible for the processing of the RNA1-encoded (P1) and RNA2-encoded (P2) polyproteins. Cleavage between the VPg and Pro domains is inefficient in vitro and in E. coli, resulting in the accumulation of the VPg-Pro. In this study, we have compared the trans-activity of the Pro and VPg-Pro on various P1- and P2-derived precursors. Recombinant Pro and VPg-Pro were partially purified using an E. coli expression system. A mutation of the VPg-Pro cleavage site was introduced into the VPg-Pro to prevent slow release of the Pro. The Pro was five to ten times more active than the VPg-Pro on two P2 cleavage sites (at the N- and C-termini of the movement protein domain) and was approximately two times more active than the VPg-Pro on the third P2 cleavage site (between the X3 and X4 domains). Neither the Pro nor the VPg-Pro could cleave in trans P1-derived substrates containing the three cleavage sites delineating the X1, X2, putative NTP-binding protein and VPg domains. These results are discussed in light of the possible regulation of the proteinase activity during virus replication.
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Affiliation(s)
- J Chisholm
- Pacific Agri-Food Research Centre, BC, V0H 1Z0, Summerland, Canada
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Léonard S, Plante D, Wittmann S, Daigneault N, Fortin MG, Laliberté JF. Complex formation between potyvirus VPg and translation eukaryotic initiation factor 4E correlates with virus infectivity. J Virol 2000; 74:7730-7. [PMID: 10933678 PMCID: PMC112301 DOI: 10.1128/jvi.74.17.7730-7737.2000] [Citation(s) in RCA: 243] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The interaction between the viral protein linked to the genome (VPg) of turnip mosaic potyvirus (TuMV) and the translation eukaryotic initiation factor eIF(iso)4E of Arabidopsis thaliana has previously been reported. eIF(iso)4E binds the cap structure (m(7)GpppN, where N is any nucleotide) of mRNAs and has an important role in the regulation in the initiation of translation. In the present study, it was shown that not only did VPg bind eIF(iso)4E but it also interacted with the eIF4E isomer of A. thaliana as well as with eIF(iso)4E of Triticum aestivum (wheat). The interaction domain on VPg was mapped to a stretch of 35 amino acids, and substitution of an aspartic acid residue found within this region completely abolished the interaction. The cap analogue m(7)GTP, but not GTP, inhibited VPg-eIF(iso)4E complex formation, suggesting that VPg and cellular mRNAs compete for eIF(iso)4E binding. The biological significance of this interaction was investigated. Brassica perviridis plants were infected with a TuMV infectious cDNA (p35Tunos) and p35TuD77N, a mutant which contained the aspartic acid substitution in the VPg domain that abolished the interaction with eIF(iso)4E. After 20 days, plants bombarded with p35Tunos showed viral symptoms, while plants bombarded with p35TuD77N remained symptomless. These results suggest that VPg-eIF(iso)4E interaction is a critical element for virus production.
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Affiliation(s)
- S Léonard
- Centre de Microbiologie et Biotechnologie, INRS-Institut Armand-Frappier, Ville de Laval, Québec, Canada H7V 1B7
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Proteinases Involved in Plant Virus Genome Expression. PROTEASES OF INFECTIOUS AGENTS 1999. [PMCID: PMC7271178 DOI: 10.1016/b978-012420510-9/50037-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This chapter discusses the proteinases involved in plant virus genome expression. The chapter focuses on virus-encoded proteinases. It gives an overall view of the use of proteolytic processing by different plant virus groups for the expression of their genomes. It also discusses that the development of full-length cDNA clones from which infectious transcripts can be produced either in vitro or in vivo, has facilitated the functional analysis of the plant virus proteinases. In spite of the high specificity of the viral proteinases, cellular substrates for animal virus proteinases have been described in this chapter. The activity of the viral proteinases can interfere with important cellular processes to favor virus replication. The recent use of proteinase inhibitors in AIDS therapy has emphasized the convenience of virus-encoded proteinases as targets of antiviral action. A mutant protein able to inhibit the activity of the TEV proteinase by manipulation of the α2-macroglobulin bait region was designed by Van Rompaey.
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Gorbalenya AE, Snijder EJ. Viral cysteine proteinases. PERSPECTIVES IN DRUG DISCOVERY AND DESIGN : PD3 1996; 6:64-86. [PMID: 32288276 PMCID: PMC7104566 DOI: 10.1007/bf02174046] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/11/1996] [Accepted: 06/13/1996] [Indexed: 11/26/2022]
Abstract
Dozens of novel cysteine proteinases have been identified in positive single-stranded RNA viruses and, for the first time, in large double-stranded DNA viruses. The majority of these proteins are distantly related to papain or chymotrypsin and may be direct descendants of primordial proteolytic enzymes. Virus genome synthesis and expression, virion formation, virion entry into the host cell, as well as cellular architecture and functioning can be under the control of viral cysteine proteinases during infection. RNA virus proteinases mediate their liberation from giant multidomain precursors in which they tend to occupy conserved positions. These proteinases possess a narrow substrate specificity, can cleave in cis and in trans, and may also have additional, nonproteolytic functions. The mechanisms of catalysis, substrate recognition and RNA binding were highlighted by the recent analysis of the three-dimensional structure of the chymotrypsin-like cysteine proteinases of two RNA viruses.
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Affiliation(s)
- Alexander E Gorbalenya
- 1M.P. Chumakov Institute of Poliomyelitis and Viral Encephalitides, Russian Academy of Medical Sciences, 142782 Moscow Region
- 2A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119899 Moscow, Russia
| | - Eric J Snijder
- 3Department of Virology, Institute of Medical Microbiology, Leiden University, P.O. Box 9600, 2300 RC Leiden, The Netherlands
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