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Solovyev AG, Atabekova AK, Lezzhov AA, Solovieva AD, Chergintsev DA, Morozov SY. Distinct Mechanisms of Endomembrane Reorganization Determine Dissimilar Transport Pathways in Plant RNA Viruses. PLANTS 2022; 11:plants11182403. [PMID: 36145804 PMCID: PMC9504206 DOI: 10.3390/plants11182403] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/02/2022] [Accepted: 09/13/2022] [Indexed: 11/22/2022]
Abstract
Plant viruses exploit the endomembrane system of infected cells for their replication and cell-to-cell transport. The replication of viral RNA genomes occurs in the cytoplasm in association with reorganized endomembrane compartments induced by virus-encoded proteins and is coupled with the virus intercellular transport via plasmodesmata that connect neighboring cells in plant tissues. The transport of virus genomes to and through plasmodesmata requires virus-encoded movement proteins (MPs). Distantly related plant viruses encode different MP sets, or virus transport systems, which vary in the number of MPs and their properties, suggesting their functional differences. Here, we discuss two distinct virus transport pathways based on either the modification of the endoplasmic reticulum tubules or the formation of motile vesicles detached from the endoplasmic reticulum and targeted to endosomes. The viruses with the movement proteins encoded by the triple gene block exemplify the first, and the potyviral system is the example of the second type. These transport systems use unrelated mechanisms of endomembrane reorganization. We emphasize that the mode of virus interaction with cell endomembranes determines the mechanism of plant virus cell-to-cell transport.
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Affiliation(s)
- Andrey G. Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
- All-Russia Research Institute of Agricultural Biotechnology, 127550 Moscow, Russia
| | - Anastasia K. Atabekova
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
| | - Alexander A. Lezzhov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
| | - Anna D. Solovieva
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
| | - Denis A. Chergintsev
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
| | - Sergey Y. Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
- Correspondence: ; Tel.: +7-(495)-939-31-98
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2
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Jiang C, Shan S, Huang Y, Mao C, Zhang H, Li Y, Chen J, Wei Z, Sun Z. The C-Terminal Transmembrane Domain of Cowpea Mild Mottle Virus TGBp2 Is Critical for Plasmodesmata Localization and for Its Interaction With TGBp1 and TGBp3. Front Microbiol 2022; 13:860695. [PMID: 35495691 PMCID: PMC9051516 DOI: 10.3389/fmicb.2022.860695] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 03/25/2022] [Indexed: 11/13/2022] Open
Abstract
The movement of some plant RNA viruses is mediated by triple gene block (TGB) proteins, which cooperate to transfer the viral genome from cell to cell through plasmodesmata. Here, we investigated the function of the TGB proteins of cowpea mild mottle virus (CPMMV; genus Carlavirus, family Betaflexiviridae), which causes severe damage to soybean production. Subcellular localization experiments demonstrated that TGBp1 and TGBp3 were localized to the endoplasmic reticulum (ER), plasmodesmata (PD) and nucleus in Nicotiana benthamiana leaves. TGBp2 was unusually localized to PD. In protein interaction assays TGBp2 significantly enhanced the interaction between TGBp3 and TGBp1. Interaction assays using deletion mutants showed that the C-terminal transmembrane (TM) domain of TGBp2 is critical for its localization to PD and for its interaction with TGBp1 and TGBp3.
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Kang SH, Aknadibossian V, Kharel L, Mudiyanselage SDD, Wang Y, Folimonova SY. The Intriguing Conundrum of a Nonconserved Multifunctional Protein of Citrus Tristeza Virus That Interacts with a Viral Long Non-Coding RNA. Viruses 2021; 13:2129. [PMID: 34834936 PMCID: PMC8625556 DOI: 10.3390/v13112129] [Citation(s) in RCA: 2] [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: 09/24/2021] [Revised: 10/12/2021] [Accepted: 10/19/2021] [Indexed: 01/26/2023] Open
Abstract
Citrus tristeza virus (CTV), the largest non-segmented plant RNA virus, has several peculiar features, among which is the production of a 5'-terminal long non-coding RNA (lncRNA) termed low-molecular-weight tristeza 1 (LMT1). In this study, we found that p33, a unique viral protein that performs multiple functions in the virus infection cycle, specifically binds LMT1, both in vivo and in vitro. These results were obtained through the expression of p33 under the context of the wild type virus infection or along with a mutant CTV variant that does not produce LMT1 as well as via ectopic co-expression of p33 with LMT1 in Nicotiana benthamiana leaves followed by RNA immunoprecipitation and rapid amplification of cDNA ends assays. Further experiments in which a recombinant p33 protein and an in vitro transcribed full-length LMT1 RNA or its truncated fragments were subjected to an electrophoretic mobility shift assay demonstrated that p33 binds to at least two distinct regions within LMT1. To the best of our knowledge, this is the first report of a plant virus protein binding to a lncRNA produced by the same virus. The biological significance of the interaction between these two viral factors is discussed.
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Affiliation(s)
- Sung-Hwan Kang
- Plant Pathology Department, University of Florida, Gainesville, FL 32611, USA; (S.-H.K.); (V.A.)
| | - Vicken Aknadibossian
- Plant Pathology Department, University of Florida, Gainesville, FL 32611, USA; (S.-H.K.); (V.A.)
| | - Laxmi Kharel
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA; (L.K.); (S.D.D.M.); (Y.W.)
| | | | - Ying Wang
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA; (L.K.); (S.D.D.M.); (Y.W.)
| | - Svetlana Y. Folimonova
- Plant Pathology Department, University of Florida, Gainesville, FL 32611, USA; (S.-H.K.); (V.A.)
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4
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Jiang Z, Zhang K, Li Z, Li Z, Yang M, Jin X, Cao Q, Wang X, Yue N, Li D, Zhang Y. The Barley stripe mosaic virus γb protein promotes viral cell-to-cell movement by enhancing ATPase-mediated assembly of ribonucleoprotein movement complexes. PLoS Pathog 2020; 16:e1008709. [PMID: 32730331 PMCID: PMC7419011 DOI: 10.1371/journal.ppat.1008709] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 08/11/2020] [Accepted: 06/17/2020] [Indexed: 02/07/2023] Open
Abstract
Nine genera of viruses in five different families use triple gene block (TGB) proteins for virus movement. The TGB modules fall into two classes: hordei-like and potex-like. Although TGB-mediated viral movement has been extensively studied, determination of the constituents of the viral ribonucleoprotein (vRNP) movement complexes and the mechanisms underlying their involvement in vRNP-mediated movement are far from complete. In the current study, immunoprecipitation of TGB1 protein complexes formed during Barley stripe mosaic virus (BSMV) infection revealed the presence of the γb protein in the products. Further experiments demonstrated that TGB1 interacts with γb in vitro and in vivo, and that γb-TGB1 localizes at the periphery of chloroplasts and plasmodesmata (PD). Subcellular localization analyses of the γb protein in Nicotiana benthamiana epidermal cells indicated that in addition to chloroplast localization, γb also targets the ER, actin filaments and PD at different stages of viral infection. By tracking γb localization during BSMV infection, we demonstrated that γb is required for efficient cell-to-cell movement. The N-terminus of γb interacts with the TGB1 ATPase/helicase domain and enhances ATPase activity of the domain. Inactivation of the TGB1 ATPase activity also significantly impaired PD targeting. In vitro translation together with co-immunoprecipitation (co-IP) analyses revealed that TGB1-TGB3-TGB2 complex formation is enhanced by ATP hydrolysis. The γb protein positively regulates complex formation in the presence of ATP, suggesting that γb has a novel role in BSMV cell-to-cell movement by directly promoting TGB1 ATPase-mediated vRNP movement complex assembly. We further demonstrated that elimination of ATPase activity abrogates PD and actin targeting of Potato virus X (PVX) and Beet necrotic yellow vein virus (BNYVV) TGB1 proteins. These results expand our understanding of the multifunctional roles of γb and provide new insight into the functions of TGB1 ATPase domains in the movement of TGB-encoding viruses.
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Affiliation(s)
- Zhihao Jiang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Kun Zhang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Zhaolei Li
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Zhenggang Li
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Meng Yang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Xuejiao Jin
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Qing Cao
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Xueting Wang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Ning Yue
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Dawei Li
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Yongliang Zhang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
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5
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Makarov VV, Makarova SS, Makhotenko AV, Obraztsova EA, Kalinina NO. In vitro properties of hordeivirus TGB1 protein forming ribonucleoprotein complexes. J Gen Virol 2015; 96:3422-3431. [PMID: 26276346 DOI: 10.1099/jgv.0.000252] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hordeivirus movement protein encoded by the first gene of the triple gene block (TGB1 protein, TGBp1) interacts in vivo with viral genomic and subgenomic RNAs to form ribonucleoprotein (RNP) particles that are considered to be a form of viral genome (non-virion transport form) capable of cell-to-cell and long-distance transport in infected plants. The structures of these RNPs have not been elucidated. The poa semilatent virus (PSLV) TGBp1 contains a structured C-terminal NTPase/helicase domain and an N-terminal extension region consisting of two domains - a completely intrinsically disordered extreme N-terminal domain and an internal domain (ID) with structure resembling a partially disordered molten globule. Here, we characterized the structures assembled in vitro by the full-length PSLV TGBp1 alone or in the presence of viral RNA. The PSLV TGBp1 was capable of multimerization and self-assembly into extended high-molecular-mass complexes. These complexes disassembled to apparent monomers upon incubation with ATP. Upon incubation with viral RNA, the PSLV TGBp1 in vitro formed RNP structures that appeared as filamentous particles resembling virions of helical filamentous plant viruses in morphology and dimensions. By comparing the biophysical characteristics of PSLV TGBp1 and its domains in the presence and absence of RNA, we show that the ID plays the main structural role in the self-interactions and RNA interactions of TGBp1 leading to the assembly of virus-like RNP particles.
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Affiliation(s)
- Valentin V Makarov
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninsky Gory, Moscow 119992, Russia
| | - Svetlana S Makarova
- Department of Biology, Lomonosov Moscow State University, Leninsky Gory, Moscow 119992, Russia
| | - Antonida V Makhotenko
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninsky Gory, Moscow 119992, Russia
| | - Ekaterina A Obraztsova
- M. M. Shemyakin and Yu. A. Ovchinnikov Bioorganic Chemistry Institute, Miklukho-Maklaya str. 16/10, Moscow 117997, Russia
| | - Natalia O Kalinina
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninsky Gory, Moscow 119992, Russia
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6
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Kim BS, Halk EL, Merlo DJ, Nelson SE, Loesch-Fries LS. Phosphorylation of alfalfa mosaic virus movement protein in vivo. Arch Virol 2014; 159:1787-91. [PMID: 24435161 DOI: 10.1007/s00705-013-1945-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 11/01/2013] [Indexed: 02/04/2023]
Abstract
The 32-kDa movement protein, P3, of alfalfa mosaic virus (AMV) is essential for cell-to-cell spread of the virus in plants. P3 shares many properties with other virus movement proteins (MPs); however, it is not known if P3 is posttranslationally modified by phosphorylation, which is important for the function of other MPs. When expressed in Nicotiana tabacum, P3 accumulated primarily in the cell walls of older leaves or in the cytosol of younger leaves. When expressed in Pischia pastoris, P3 accumulated primarily in a soluble form. Metabolic labeling indicated that a portion of P3 was phosphorylated in both tobacco and yeast, suggesting that phosphorylation regulates the function of this protein as it does for other virus MPs.
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Affiliation(s)
- Bong-Suk Kim
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
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7
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Xue B, Blocquel D, Habchi J, Uversky AV, Kurgan L, Uversky VN, Longhi S. Structural disorder in viral proteins. Chem Rev 2014; 114:6880-911. [PMID: 24823319 DOI: 10.1021/cr4005692] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Bin Xue
- Department of Cell Biology, Microbiology and Molecular Biology, College of Fine Arts and Sciences, and ‡Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida , Tampa, Florida 33620, United States
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8
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Hyodo K, Kaido M, Okuno T. Host and viral RNA-binding proteins involved in membrane targeting, replication and intercellular movement of plant RNA virus genomes. FRONTIERS IN PLANT SCIENCE 2014; 5:321. [PMID: 25071804 PMCID: PMC4083346 DOI: 10.3389/fpls.2014.00321] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 06/18/2014] [Indexed: 05/10/2023]
Abstract
Many plant viruses have positive-strand RNA [(+)RNA] as their genome. Therefore, it is not surprising that RNA-binding proteins (RBPs) play important roles during (+)RNA virus infection in host plants. Increasing evidence demonstrates that viral and host RBPs play critical roles in multiple steps of the viral life cycle, including translation and replication of viral genomic RNAs, and their intra- and intercellular movement. Although studies focusing on the RNA-binding activities of viral and host proteins, and their associations with membrane targeting, and intercellular movement of viral genomes have been limited to a few viruses, these studies have provided important insights into the molecular mechanisms underlying the replication and movement of viral genomic RNAs. In this review, we briefly overview the currently defined roles of viral and host RBPs whose RNA-binding activity have been confirmed experimentally in association with their membrane targeting, and intercellular movement of plant RNA virus genomes.
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Affiliation(s)
| | | | - Tetsuro Okuno
- *Correspondence: Tetsuro Okuno, Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Sakyo-ku,Kyoto 606-8502, Japan e-mail:
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9
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Makarov VV, Skurat EV, Semenyuk PI, Abashkin DA, Kalinina NO, Arutyunyan AM, Solovyev AG, Dobrov EN. Structural lability of Barley stripe mosaic virus virions. PLoS One 2013; 8:e60942. [PMID: 23613760 PMCID: PMC3629216 DOI: 10.1371/journal.pone.0060942] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 03/04/2013] [Indexed: 11/29/2022] Open
Abstract
Virions of Barley stripe mosaic virus (BSMV) were neglected for more than thirty years after their basic properties were determined. In this paper, the physicochemical characteristics of BSMV virions and virion-derived viral capsid protein (CP) were analyzed, namely, the absorption and intrinsic fluorescence spectra, circular dichroism spectra, differential scanning calorimetry curves, and size distributions by dynamic laser light scattering. The structural properties of BSMV virions proved to be intermediate between those of Tobacco mosaic virus (TMV), a well-characterized virus with rigid rod-shaped virions, and flexuous filamentous plant viruses. The BSMV virions were found to be considerably more labile than expected from their rod-like morphology and a distant sequence relation of the BSMV and TMV CPs. The circular dichroism spectra of BSMV CP subunits incorporated into the virions, but not subunits of free CP, demonstrated a significant proportion of beta-structure elements, which were proposed to be localized mostly in the protein regions exposed on the virion outer surface. These beta-structure elements likely formed during virion assembly can comprise the N- and C-terminal protein regions unstructured in the non-virion CP and can mediate inter-subunit interactions. Based on computer-assisted structure modeling, a model for BSMV CP subunit structural fold compliant with the available experimental data was proposed.
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Affiliation(s)
- Valentin V. Makarov
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
- Biology Department, Lomonosov Moscow State University, Moscow, Russia
| | - Eugeny V. Skurat
- Biology Department, Lomonosov Moscow State University, Moscow, Russia
| | - Pavel I. Semenyuk
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia
| | - Dmitry A. Abashkin
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia
| | - Natalya O. Kalinina
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Alexsandr M. Arutyunyan
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Andrey G. Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Eugeny N. Dobrov
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
- * E-mail:
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Makarov VV, Iconnikova AY, Guseinov MA, Vishnichenko VK, Kalinina NO. In vitro phosphorylation of the N-terminal half of hordeivirus movement protein. BIOCHEMISTRY. BIOKHIMIIA 2012; 77:1072-81. [PMID: 23157268 DOI: 10.1134/s0006297912090155] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The N-terminal half of TGB1 movement protein of poa semilatent hordeivirus, which forms a ribonucleoprotein complex involved in movement of the viral genome in the plant, and its two domains, NTD and ID, are phosphorylated in vitro by a fraction enriched in cell walls from Nicotiana benthamiana. Using a set of protein kinase inhibitors with different specificities, it was found that enzymes possessing activities of casein kinase 1, protein kinase A, and protein kinase C are involved in phosphorylation. Commercial preparations of protein kinases A and C are able to phosphorylate in vitro recombinant proteins corresponding to the N-terminal half of the protein and its domains NTD and ID. Phosphorylation of the NTD has no effect on the efficiency and character of its binding to RNA. However, phosphorylation of the ID leads to a decrease in its RNA-binding activity and in the ability for homological protein-protein interactions.
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Affiliation(s)
- V V Makarov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
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Semashko MA, Rakitina DV, González I, Canto T, Kalinina NO, Taliansky ME. Movement protein of hordeivirus interacts in vitro and in vivo with coilin, a major structural protein of Cajal bodies. DOKL BIOCHEM BIOPHYS 2012; 442:57-60. [PMID: 22419098 DOI: 10.1134/s1607672912010164] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Indexed: 12/18/2022]
Affiliation(s)
- M A Semashko
- Belozersky Institute of Physico-Chemical Biology and Biological Faculty of Lomonosov Moscow State University, Moscow, Russia
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12
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Semashko MA, González I, Shaw J, Leonova OG, Popenko VI, Taliansky ME, Canto T, Kalinina NO. The extreme N-terminal domain of a hordeivirus TGB1 movement protein mediates its localization to the nucleolus and interaction with fibrillarin. Biochimie 2012; 94:1180-8. [PMID: 22349738 DOI: 10.1016/j.biochi.2012.02.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 02/06/2012] [Indexed: 01/13/2023]
Abstract
The hordeiviral movement protein encoded by the first gene of the triple gene block (TGBp1) of Poa semilatent virus (PSLV), interacts with viral genomic RNAs to form RNP particles which are considered to be a form of viral genome capable of cell-to-cell and long-distance transport in infected plants. The PSLV TGBp1 contains a C-terminal NTPase/helicase domain (HELD) and an N-terminal extension region consisting of two structurally and functionally distinct domains: an extreme N-terminal domain (NTD) and an internal domain (ID). This study demonstrates that transient expression of TGBp1 fused to GFP in Nicotiana benthamiana leaves results in faint but obvious fluorescence in the nucleolus in addition to cytosolic distribution. Mutagenesis of the basic amino acids inside the NTD clusters A (116)KSKRKKKNKK(125) and B (175)KKATKKESKKQTK(187) reveals that these clusters are indispensable for nuclear and nucleolar targeting of PSLV TGBp1 and may contain nuclear and nucleolar localization signals or their elements. The PSLV TGBp1 is able to bind to fibrillarin, the major nucleolar protein (AtFib2 from Arabidopsis thaliana) in vitro. This protein-protein interaction occurs between the glycine-arginine-rich (GAR) domain of fibrillarin and the first 82 amino acid residues of TGBp1. The interaction of TGBp1 with fibrillarin is also visualized in vivo by bimolecular fluorescence complementation (BiFC) during co-expression of TGBp1 or its deletion mutants, and fibrillarin as fusions to different halves of YFP in N. benthamiana plants. The sites responsible for nuclear/nucleolar localization and fibrillarin binding, have been located within the intrinsically disordered TGBp1 NTD. These data could suggest that specific functions of hordeivirus TGBp1 may depend on its interaction with nucleolar components.
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Affiliation(s)
- Maria A Semashko
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninsky Gory, Moscow, 119992, Russia
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13
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Torrance L, Wright KM, Crutzen F, Cowan GH, Lukhovitskaya NI, Bragard C, Savenkov EI. Unusual features of pomoviral RNA movement. Front Microbiol 2011; 2:259. [PMID: 22203822 PMCID: PMC3244614 DOI: 10.3389/fmicb.2011.00259] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 12/02/2011] [Indexed: 01/10/2023] Open
Abstract
Potato mop-top pomovirus (PMTV) is one of a few viruses that can move systemically in plants in the absence of the capsid protein (CP). Pomoviruses encode the triple gene block genetic module of movement proteins (TGB 1, 2, and 3) and recent research suggests that PMTV RNA is transported either as ribonucleoprotein (RNP) complexes containing TGB1 or encapsidated in virions containing TGB1. Furthermore, there are different requirements for local or systemic (long-distance) movement. Research suggests that nucleolar passage of TGB1 may be important for the long-distance movement of both RNP and virions. Moreover, and uniquely, the long-distance movement of the CP-encoding RNA requires expression of both major and minor CP subunits and is inhibited when only the major CP sub unit is expressed. This paper reviews pomovirus research and presents a current model for RNA movement.
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Affiliation(s)
- Lesley Torrance
- Cell and Molecular Sciences, The James Hutton Institute Dundee, UK
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14
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Rakitina DV, Taliansky M, Brown JWS, Kalinina NO. Two RNA-binding sites in plant fibrillarin provide interactions with various RNA substrates. Nucleic Acids Res 2011; 39:8869-80. [PMID: 21785141 PMCID: PMC3203579 DOI: 10.1093/nar/gkr594] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Fibrillarin, one of the major proteins of the nucleolus, plays several essential roles in ribosome biogenesis including pre-rRNA processing and 2′-O-ribose methylation of rRNA and snRNAs. Recently, it has been shown that fibrillarin plays a role in virus infections and is associated with viral RNPs. Here, we demonstrate the ability of recombinant fibrillarin 2 from Arabidopsis thaliana (AtFib2) to interact with RNAs of different lengths and types including rRNA, snoRNA, snRNA, siRNA and viral RNAs in vitro. Our data also indicate that AtFib2 possesses two RNA-binding sites in the central (138–179 amino acids) and C-terminal (225–281 amino acids) parts of the protein, respectively. The conserved GCVYAVEF octamer does not bind RNA directly as suggested earlier, but may assist with the proper folding of the central RNA-binding site.
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Affiliation(s)
- D. V. Rakitina
- Department of Virology and A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119991, Russia, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK and Plant Sciences Division, University of Dundee, DD2 5DA, UK
| | - Michael Taliansky
- Department of Virology and A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119991, Russia, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK and Plant Sciences Division, University of Dundee, DD2 5DA, UK
- *To whom correspondence should be addressed. Tel: +44(0)1382562731; Fax: +44 (0)1382 562426;
| | - J. W. S. Brown
- Department of Virology and A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119991, Russia, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK and Plant Sciences Division, University of Dundee, DD2 5DA, UK
| | - N. O. Kalinina
- Department of Virology and A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119991, Russia, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK and Plant Sciences Division, University of Dundee, DD2 5DA, UK
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15
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Shemyakina EA, Erokhina TN, Gorshkova EN, Schiemann J, Solovyev AG, Morozov SY. Formation of protein complexes containing plant virus movement protein TGBp3 is necessary for its intracellular trafficking. Biochimie 2011; 93:742-8. [PMID: 21251950 DOI: 10.1016/j.biochi.2011.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Accepted: 01/11/2011] [Indexed: 12/11/2022]
Abstract
Cell-to-cell movement of Poa semilatent virus (genus Hordeivirus) in infected plants is mediated by three viral 'triple gene block' (TGB) proteins. One of those termed TGBp3 is an integral membrane protein essential for intracellular transport of other TGB proteins and viral genomic RNA to plasmodesmata. TGBp3 targeting to plasmodesmata-associated sites is believed to involve an unconventional mechanism which does not employ endoplasmic reticulum-derived transport vesicles. Previously TGBp3 has been shown to contain a composite transport signal consisting of the central hydrophilic protein region which includes a conserved pentapeptide YQDLN and the C-terminal transmembrane segment. This study demonstrates that these TGBp3 structural elements have distinct functions in protein transport. The YQDLN-containing region is essential for TGBp3 incorporation into high-molecular-mass protein complexes. In transient expression assay formation of such complexes is necessary for entering the TGBp3-specific pathway of intracellular transport and protein delivery to plasmodesmata-associated sites. In virus-infected plants TGBp3 is also found predominantly in the form of high-molecular-mass complexes. When the complex-formation function of YQDLN-containing region is disabled by a mutation, targeting to plasmodesmata-associated sites can be complemented by a heterologous peptide capable of formation multimeric complexes. The C-terminal transmembrane segment is found to be an essential signal of TGBp3 intracellular transport to peripheral sites.
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Affiliation(s)
- Elena A Shemyakina
- Department of Virology, Biological Faculty, Moscow State University, Moscow, Russia
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16
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Shemyakina EA, Solovyev AG, Leonova OG, Popenko VI, Schiemann J, Morozov SY. The Role of Microtubule Association in Plasmodesmal Targeting of Potato mop-top virus Movement Protein TGBp1. Open Virol J 2011; 5:1-11. [PMID: 21660184 PMCID: PMC3109696 DOI: 10.2174/1874357901105010001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 10/11/2010] [Accepted: 10/25/2010] [Indexed: 12/19/2022] Open
Abstract
Cell-to-cell movement of Potato mop-top virus (PMTV) is mediated by three virus-encoded ‘triple gene block’ (TGB) proteins termed TGBp1, TGBp2 and TGBp3. TGBp1 binds virus RNAs to form viral ribonucleoprotein complexes (vRNPs), the transport form of viral genome. TGBp2 and TGBp3 are necessary for intracellular delivery of TGBp1-containing vRNPs to plasmodesmata. To analyze subcellular localization and transport of TGBp1 we used a single binary vector for agrobacterium-mediated co-expression of PMTV TGBp1 fused to green fluorescent protein and TGBp2/TGBp3. At two days post infiltration (dpi) TGBp1 was found in the nucleus and in association with microtubules (MTs). Similar localization pattern was revealed in cells expressing GFP-TGBp1 alone after particle bombardment. At 3 dpi, in addition to the nucleus and MTs, TGBp1 was detected in numerous granular bodies located both along the MTs and at the cell wall. The latter structures co-localized with plasmodesmata-associated callose depositions. At 4 dpi, GFP-TGBp1 was detected in cell wall-associated bodies and also in residual MTs, the nucleoplasm and large perinuclear inclusions resembling aggresomes. Therefore GFP-TGBp1 association with MTs preceded to its localization to plasmodesmata. Disassembly of cell MTs by colchicine prevented GFP-TGBp1 targeting to plasmodesmata and the MT-dependent aggresome formation. Deletion analysis also revealed a correlation between TGBp1 microtubule association and plasmodesmata targeting. We propose that TGBp1 interaction with MTs may be important for the formation of vRNP bodies destined for the transport to plasmodesmata as well as degradation of the excessive TGBp1.
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Affiliation(s)
- Elena A Shemyakina
- Department of Virology, Biological Faculty, Moscow State University, Moscow, 119992, Russia
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17
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Wright KM, Cowan GH, Lukhovitskaya NI, Tilsner J, Roberts AG, Savenkov EI, Torrance L. The N-terminal domain of PMTV TGB1 movement protein is required for nucleolar localization, microtubule association, and long-distance movement. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:1486-97. [PMID: 20923354 DOI: 10.1094/mpmi-05-10-0105] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The triple-gene-block (TGB)1 protein of Potato mop-top virus (PMTV) was fused to fluorescent proteins and expressed in epidermal cells of Nicotiana benthamiana under the control of the 35S promoter. TGB1 fluorescence was observed in the cytoplasm, nucleus, and nucleolus and occasionally associated with microtubules. When expressed from a modified virus (PMTV.YFP-TGB1) which formed local lesions but was not competent for systemic movement, yellow fluorescent protein (YFP)-TGB1 labeled plasmodesmata in cells at the leading edge of the lesion and plasmodesmata, microtubules, nuclei, and nucleoli in cells immediately behind the leading edge. Deletion of 84 amino acids from the N-terminus of unlabeled TGB1 within the PMTV genome abolished movement of viral RNA to noninoculated leaves. When the same deletion was introduced into PMTV.YFP-TGB1, labeling of microtubules and nucleoli was abolished. The N-terminal 84 amino acids of TGB1 were fused to green fluorescent protein (GFP) and expressed in epidermal cells where GFP localized strongly to the nucleolus (not seen with unfused GFP), indicating that these amino acids contain a nucleolar localization signal; the fusion protein did not label microtubules. This is the first report of nucleolar and microtubule association of a TGB movement protein. The results suggest that PMTV TGB1 requires interaction with nuclear components and, possibly, microtubules for long-distance movement of viral RNA.
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Affiliation(s)
- Kathryn M Wright
- Plant Pathology Programme, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UK
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18
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Verchot-Lubicz J, Torrance L, Solovyev AG, Morozov SY, Jackson AO, Gilmer D. Varied movement strategies employed by triple gene block-encoding viruses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:1231-47. [PMID: 20831404 DOI: 10.1094/mpmi-04-10-0086] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Several RNA virus genera belonging to the Virgaviridae and Flexiviridae families encode proteins organized in a triple gene block (TGB) that facilitate cell-to-cell and long-distance movement. The TGB proteins have been traditionally classified as hordei-like or potex-like based on phylogenetic comparisons and differences in movement mechanisms of the Hordeivirus and Potexvirus spp. However, accumulating data from other model viruses suggests that a revised framework is needed to accommodate the profound differences in protein interactions occurring during infection and ancillary capsid protein requirements for movement. The goal of this article is to highlight common features of the TGB proteins and salient differences in movement properties exhibited by individual viruses encoding these proteins. We discuss common and divergent aspects of the TGB transport machinery, describe putative nucleoprotein movement complexes, highlight recent data on TGB protein interactions and topological properties, and review membrane associations occurring during subcellular targeting and cell-to-cell movement. We conclude that the existing models cannot be used to explain all TGB viruses, and we propose provisional Potexvirus, Hordeivirus, and Pomovirus models. We also suggest areas that might profit from future research on viruses harboring this intriguing arrangement of movement proteins.
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Affiliation(s)
- Jeanmarie Verchot-Lubicz
- Oklahoma State University, Department of Entomology and Plant Pathology, Stillwater, OK 74078, USA.
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19
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Makarov VV, Obraztsova EA, Solovyev AG, Morozov SY, Taliansky ME, Yaminsky IV, Kalinina NO. The internal domain of hordeivirus movement protein TGB1 forms in vitro filamentous structures. BIOCHEMISTRY (MOSCOW) 2010; 75:752-8. [DOI: 10.1134/s0006297910060106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Makarov VV, Rybakova EN, Efimov AV, Dobrov EN, Serebryakova MV, Solovyev AG, Yaminsky IV, Taliansky ME, Morozov SY, Kalinina NO. Domain organization of the N-terminal portion of hordeivirus movement protein TGBp1. J Gen Virol 2009; 90:3022-3032. [DOI: 10.1099/vir.0.013862-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Three ‘triple gene block’ proteins known as TGBp1, TGBp2 and TGBp3 are required for cell-to-cell movement of plant viruses belonging to a number of genera including Hordeivirus. Hordeiviral TGBp1 interacts with viral genomic RNAs to form ribonucleoprotein (RNP) complexes competent for translocation between cells through plasmodesmata and over long distances via the phloem. Binding of hordeivirus TGBp1 to RNA involves two protein regions, the C-terminal NTPase/helicase domain and the N-terminal extension region. This study demonstrated that the extension region of hordeivirus TGBp1 consists of two structurally and functionally distinct domains called the N-terminal domain (NTD) and the internal domain (ID). In agreement with secondary structure predictions, analysis of circular dichroism spectra of the isolated NTD and ID demonstrated that the NTD represents a natively unfolded protein domain, whereas the ID has a pronounced secondary structure. Both the NTD and ID were able to bind ssRNA non-specifically. However, whilst the NTD interacted with ssRNA non-cooperatively, the ID bound ssRNA in a cooperative manner. Additionally, both domains bound dsRNA. The NTD and ID formed low-molecular-mass oligomers, whereas the ID also gave rise to high-molecular-mass complexes. The isolated ID was able to interact with both the NTD and the C-terminal NTPase/helicase domain in solution. These data demonstrate that the hordeivirus TGBp1 has three RNA-binding domains and that interaction between these structural units can provide a basis for remodelling of viral RNP complexes at different steps of cell-to-cell and long-distance transport of virus infection.
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Affiliation(s)
- Valentin V. Makarov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia
| | - Ekaterina N. Rybakova
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia
| | - Alexander V. Efimov
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia
| | - Eugene N. Dobrov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia
| | | | - Andrey G. Solovyev
- Institute of Agricultural Biotechnology, Russian Academy of Agricultural Sciences, Moscow 127550, Russia
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia
| | - Igor V. Yaminsky
- Physical Faculty, Moscow State University, Moscow 119992, Russia
| | | | - Sergey Yu. Morozov
- Department of Virology, Biological Faculty, Moscow State University, Moscow 119992, Russia
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia
| | - Natalia O. Kalinina
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia
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21
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Ji X, Wei C, Li Y. Expression of rice dwarf phytoreovirus Pns6 and the specificity analysis of its monoclonal antibodies. SCIENCE IN CHINA. SERIES C, LIFE SCIENCES 2009; 52:958-64. [PMID: 19911132 DOI: 10.1007/s11427-009-0129-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Accepted: 05/16/2009] [Indexed: 10/20/2022]
Abstract
The genome of rice dwarf phytoreovirus (RDV) is composed of 12 double-stranded RNA segments, of which segment S6 encodes a non-structural protein Pns6 identified as the movement protein. In this report, Pns6 with a 6-histidine tag at the N-terminal was expressed in E. coli after induction under low temperature (18 degrees C) and low concentration (0.4 mmol/L and 0.2 mmol/L) of IPTG, and then purified by Ni-chelated affinity chromatography. Stability analysis indicated that the expressed HisPns6 protein was stable at 37 degrees C after 24 h treatment. This recombinant protein was then used to make monoclonal antibody. Total 18 hybridoma clones were obtained. The specificity of antibodies was tested by Western blot using native Pns6 extracted from RDV-infected rice leaves, and 15 positive clones were confirmed. Mapping of the antigenic sites of Pns6 using antibodies showed that the most sensitive antigen determinant is located in the C-terminal region (the 296th-509th amino acids) of Pns6, which is confirms bioinformatics analysis.
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Affiliation(s)
- Xu Ji
- Peking-Yale Joint Center for Plant Molecular Genetics and Agrobiotechnology, National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing, 100871, China
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22
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Genovés A, Navarro JA, Pallás V. A self-interacting carmovirus movement protein plays a role in binding of viral RNA during the cell-to-cell movement and shows an actin cytoskeleton dependent location in cell periphery. Virology 2009; 395:133-42. [PMID: 19796783 DOI: 10.1016/j.virol.2009.08.042] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 08/12/2009] [Accepted: 08/30/2009] [Indexed: 10/20/2022]
Abstract
The p7A of Melon necrotic spot virus has been described to be a RNA-binding movement protein essential for cell-to-cell movement but its role in this process is still unknown. Here, we found that primary and secondary structure elements on p7A appear to form a composite RNA-binding site required for both RNA interaction and cell-to-cell movement in plants indicating a direct correlation between these activities. Furthermore, we found that fluorescent-tagged p7A was distributed in punctuate structures at the cell periphery but also in motile cytoplasmic inclusion bodies which were in close association with the actin MFs and most likely generated by self-interacting p7A molecules as shown by BiFC assays. Consistently, the p7A subcellular distribution was revealed to be sensitive to the actin inhibitor, latrunculin B. The involvement of the RNA-binding capabilities and the subcellular location of the p7A in the intracellular and intercellular virus movement is discussed.
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Affiliation(s)
- Ainhoa Genovés
- Instituto de Biología Molecular y Celular de Plantas (IBMCP). UPV-CSIC, Avda. de los Naranjos s/n, Valencia, Spain.
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23
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Lim HS, Bragg JN, Ganesan U, Ruzin S, Schichnes D, Lee MY, Vaira AM, Ryu KH, Hammond J, Jackson AO. Subcellular localization of the barley stripe mosaic virus triple gene block proteins. J Virol 2009; 83:9432-48. [PMID: 19570874 PMCID: PMC2738231 DOI: 10.1128/jvi.00739-09] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 06/22/2009] [Indexed: 02/07/2023] Open
Abstract
Barley stripe mosaic virus (BSMV) spreads from cell to cell through the coordinated actions of three triple gene block (TGB) proteins (TGB1, TGB2, and TGB3) arranged in overlapping open reading frames (ORFs). Our previous studies (D. M. Lawrence and A. O. Jackson, J. Virol. 75:8712-8723, 2001; D. M. Lawrence and A. O. Jackson, Mol. Plant Pathol. 2:65-75, 2001) have shown that each of these proteins is required for cell-to-cell movement in monocot and dicot hosts. We recently found (H.-S. Lim, J. N. Bragg, U. Ganesan, D. M. Lawrence, J. Yu, M. Isogai, J. Hammond, and A. O. Jackson, J. Virol. 82:4991-5006, 2008) that TGB1 engages in homologous interactions leading to the formation of a ribonucleoprotein complex containing viral genomic and messenger RNAs, and we have also demonstrated that TGB3 functions in heterologous interactions with TGB1 and TGB2. We have now used Agrobacterium tumefaciens-mediated protein expression in Nicotiana benthamiana leaf cells and site-specific mutagenesis to determine how TGB protein interactions influence their subcellular localization and virus spread. Confocal microscopy revealed that the TGB3 protein localizes at the cell wall (CW) in close association with plasmodesmata and that the deletion or mutagenesis of a single amino acid at the immediate C terminus can affect CW targeting. TGB3 also directed the localization of TGB2 from the endoplasmic reticulum to the CW, and this targeting was shown to be dependent on interactions between the TGB2 and TGB3 proteins. The optimal localization of the TGB1 protein at the CW also required TGB2 and TGB3 interactions, but in this context, site-specific TGB1 helicase motif mutants varied in their localization patterns. The results suggest that the ability of TGB1 to engage in homologous binding interactions is not essential for targeting to the CW. However, the relative expression levels of TGB2 and TGB3 influenced the cytosolic and CW distributions of TGB1 and TGB2. Moreover, in both cases, localization at the CW was optimal at the 10:1 TGB2-to-TGB3 ratios occurring in virus infections, and mutations reducing CW localization had corresponding effects on BSMV movement phenotypes. These data support a model whereby TGB protein interactions function in the subcellular targeting of movement protein complexes and the ability of BSMV to move from cell to cell.
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Affiliation(s)
- Hyoun-Sub Lim
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - Jennifer N. Bragg
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - Uma Ganesan
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - Steven Ruzin
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - Denise Schichnes
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - Mi Yeon Lee
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - Anna Maria Vaira
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - Ki Hyun Ryu
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - John Hammond
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - Andrew O. Jackson
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
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24
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Lukhovitskaya NI, Ignatovich IV, Savenkov EI, Schiemann J, Morozov SY, Solovyev AG. Role of the zinc-finger and basic motifs of chrysanthemum virus B p12 protein in nucleic acid binding, protein localization and induction of a hypersensitive response upon expression from a viral vector. J Gen Virol 2009; 90:723-733. [PMID: 19218219 DOI: 10.1099/vir.0.005025-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
The genomes of carlaviruses encode cysteine-rich proteins (CRPs) of unknown function. The 12 kDa CRP of chrysanthemum virus B (CVB), p12, has been shown previously to induce a hypersensitive response (HR) when expressed from potato virus X (PVX). This study demonstrated that a p12-induced HR was preceded by induction of a number of genes related to pathogenesis, stress and systemic acquired resistance. p12 localized predominantly to the nucleus. Interestingly, it was found that p12 bound both RNA and DNA in vitro, but notably exhibited a preference for DNA in the presence of Zn(2+) ions. Mutational analysis of the p12 conserved sequence motifs demonstrated that the basic motif is required for p12 translocation to the nucleus, thus representing part of the protein nuclear localization signal, whereas the predicted zinc finger motif is needed for both Zn(2+)-dependent DNA binding and eliciting an HR in PVX-infected leaves. Collectively, these results link, for the first time, nuclear localization of the protein encoded by a cytoplasmically replicating virus and its DNA-binding capacity with HR induction. Furthermore, these data suggest that p12 may mediate induction of the host genes by binding to the plant genomic DNA, and emphasize that CVB p12 is functionally distinct from other known nuclear-localized proteins encoded by the plant positive-stranded RNA viruses.
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Affiliation(s)
- N I Lukhovitskaya
- Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences (SLU), Box 7080, SE-750 07 Uppsala, Sweden
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
| | - I V Ignatovich
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
| | - E I Savenkov
- Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences (SLU), Box 7080, SE-750 07 Uppsala, Sweden
| | - J Schiemann
- Julius Kühn Institute (JKI), Federal Research Centre for Cultivated Plants, Institute for Biosafety of Genetically Modified Plants, Messeweg 11/12, D-38104 Braunschweig, Germany
| | - S Yu Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
| | - A G Solovyev
- Institute of Agricultural Biotechnology, Russian Academy of Agricultural Sciences, Timiryazevskaya 42, 127550 Moscow, Russia
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
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25
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Jackson AO, Lim HS, Bragg J, Ganesan U, Lee MY. Hordeivirus replication, movement, and pathogenesis. ANNUAL REVIEW OF PHYTOPATHOLOGY 2009; 47:385-422. [PMID: 19400645 DOI: 10.1146/annurev-phyto-080508-081733] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The last Hordeivirus review appearing in this series 20 years ago focused on the comparative biology, relationships, and genome organization of members of the genus ( 68 ). Prior to the 1989 review, useful findings about the origin, disease occurrence, host ranges, and general biological properties of Barley stripe mosaic virus (BSMV) were summarized in three comprehensive reviews ( 26, 67, 107 ). Several recent reviews emphasizing contemporary molecular genetic findings also may be of interest to various readers ( 15, 37, 42, 69, 70, 88, 113 ). In the current review, we briefly reiterate the biological properties of the four members of the Hordeivirus genus and describe advances in our understanding of organization and expression of the viral genomes. We also discuss the infection processes and pathogenesis of the most extensively characterized Hordeiviruses and frame these advances in the broader context of viruses in other families that have encoded triple gene block proteins. In addition, an overview of recent advances in the use of BSMV for virus-induced gene silencing is presented.
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Affiliation(s)
- Andrew O Jackson
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA.
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26
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Probing interactions between plant virus movement proteins and nucleic acids. Methods Mol Biol 2008. [PMID: 18370264 DOI: 10.1007/978-1-59745-102-4_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Most plant viruses move between plant cells with the help of their movement proteins (MPs). MPs are multifunctional proteins, and one of their functions is almost invariably binding to nucleic acids. Presumably, the MP-nucleic acid interaction is directly involved in formation of nucleoprotein complexes that function as intermediates in the cell-to-cell transport of many plant viruses. Thus, when studying a viral MP, it is important to determine whether or not it binds nucleic acids, and to characterize the hallmark parameters of such binding, i.e., preference for single- or double-stranded nucleic acids and binding cooperativity and sequence specificity. Here, we present two major experimental approaches, native gel mobility shift assay and ultra violet (UV) light cross-linking, for detection and characterization of MP binding to DNA and RNA molecules. We also describe protocols for purification of recombinant viral MPs over-expressed in bacteria and production of different DNA and RNA probes for these binding assays.
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Schepetilnikov MV, Solovyev AG, Gorshkova EN, Schiemann J, Prokhnevsky AI, Dolja VV, Morozov SY. Intracellular targeting of a hordeiviral membrane-spanning movement protein: sequence requirements and involvement of an unconventional mechanism. J Virol 2008; 82:1284-93. [PMID: 18032484 PMCID: PMC2224415 DOI: 10.1128/jvi.01164-07] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Accepted: 11/12/2007] [Indexed: 12/14/2022] Open
Abstract
The membrane-spanning protein TGBp3 is one of the three movement proteins (MPs) of Poa semilatent virus. TGBp3 is thought to direct other viral MPs and genomic RNA to peripheral bodies located in close proximity to plasmodesmata. We used the ectopic expression of green fluorescent protein-fused TGBp3 in epidermal cells of Nicotiana benthamiana leaves to study the TGBp3 intracellular trafficking pathway. Treatment with inhibitors was used to reveal that the targeting of TGBp3 to plasmodesmata does not require a functional cytoskeleton or secretory system. In addition, the suppression of endoplasmic reticulum-derived vesicle formation by a dominant negative mutant of small GTPase Sar1 had no detectable effect on TGBp3 trafficking to peripheral bodies. Collectively, these results suggested the involvement of an unconventional pathway in the intracellular transport of TGBp3. The determinants of targeting to plasmodesmata were localized to the C-terminal region of TGBp3, including the conserved hydrophilic and terminal membrane-spanning domains.
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Affiliation(s)
- Mikhail V Schepetilnikov
- Department of Botany and Plant Pathology, Oregon State University, Cordley Hall 2082, Corvallis, OR 97331, USA
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Abstract
Plant viruses spread from the initially infected cells to the rest of the plant in several distinct stages. First, the virus (in the form of virions or nucleic acid protein complexes) moves intracellularly from the sites of replication to plasmodesmata (PD, plant-specific intercellular membranous channels), the virus then transverses the PD to spread intercellularly (cell-to-cell movement). Long-distance movement of virus occurs through phloem sieve tubes. The processes of plant virus movement are controlled by specific viral movement proteins (MPs). No extensive sequence similarity has been found in MPs belonging to different plant virus taxonomic groups. Moreover, different MPs were shown to use different pathways and mechanisms for virus transport. Some viral transport systems require a single MP while others require additional virus-encoded proteins to transport viral genomes. In this review, we focus on the functions and properties of different classes of MPs encoded by RNA containing plant viruses.
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Leshchiner AD, Solovyev AG, Morozov SY, Kalinina NO. A minimal region in the NTPase/helicase domain of the TGBp1 plant virus movement protein is responsible for ATPase activity and cooperative RNA binding. J Gen Virol 2006; 87:3087-3095. [PMID: 16963768 DOI: 10.1099/vir.0.81971-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The TGBp1 protein, encoded in the genomes of a number of plant virus genera as the first gene of the 'triple gene block', possesses an NTPase/helicase domain characterized by seven conserved sequence motifs. It has been shown that the TGBp1 NTPase/helicase domain exhibits NTPase, RNA helicase and RNA-binding activities. In this paper, we have analysed a series of deletion and point mutants in the TGBp1 proteins encoded by Potato virus X (PVX, genus Potexvirus) and Poa semilatent virus (PSLV, genus Hordeivirus) to map functional regions responsible for their biochemical activities in vitro. It was found that, in both PVX and PSLV, the N-terminal part of the TGBp1 NTPase/helicase domain comprising conserved motifs I, Ia and II was sufficient for ATP hydrolysis, RNA binding and homologous protein-protein interactions. Point mutations in a single conserved basic amino acid residue upstream of motif I had little effect on the activities of C-terminally truncated mutants of both TGBp1 proteins. However, when introduced into the full-length NTPase/helicase domains, these mutations caused a substantial decrease in the ATPase activity of the protein, suggesting that the conserved basic amino acid residue upstream of motif I was required to maintain a reaction-competent conformation of the TGBp1 ATPase active site.
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Affiliation(s)
- Anna D Leshchiner
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia
| | - Andrey G Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia
| | - Sergey Yu Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia
| | - Natalia O Kalinina
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia
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30
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Erhardt M, Vetter G, Gilmer D, Bouzoubaa S, Richards K, Jonard G, Guilley H. Subcellular localization of the Triple Gene Block movement proteins of Beet necrotic yellow vein virus by electron microscopy. Virology 2005; 340:155-66. [PMID: 16023167 DOI: 10.1016/j.virol.2005.06.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Revised: 06/01/2005] [Accepted: 06/07/2005] [Indexed: 11/16/2022]
Abstract
The Triple Gene Block proteins TGBp1, TGBp2, and TGBp3 of Beet necrotic yellow vein virus (BNYVV) are required for efficient cell-to-cell spread of the infection. The TGB proteins can drive cell-to-cell movement of BNYVV in trans when expressed from a co-inoculated BNYVV RNA 3-based 'replicon'. TGBp2 and TGBp3 expressed from the replicon were nonfunctional in this assay if they were fused to the green fluorescent protein (GFP), but addition of a hemagglutinin (HA) tag to their C-termini did not incapacitate movement. Immunogold labeling of ultrathin sections treated with HA-specific antibodies localized TGBp2-HA and TGBp3-HA to what are probably structurally modified plasmodesmata (Pd) in infected cells. A similar subcellular localization was observed for TGBp1. Large gold-decorated membrane-rich bodies containing what appear to be short fragments of endoplasmic reticulum were observed near the cell periphery. The modified gold-decorated Pd and the membrane-rich bodies were not observed when the TGB proteins were produced individually in infections using the Tobacco mosaic virus P30 protein to drive cell-to-cell movement, indicating that these modifications are specific for TGB-mediated movement.
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Affiliation(s)
- M Erhardt
- Institut de Biologie Moléculaire des Plantes du CNRS et de l'Université Louis Pasteur, 67084 Strasbourg, France
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31
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Schepetilnikov MV, Manske U, Solovyev AG, Zamyatnin AA, Schiemann J, Morozov SY. The hydrophobic segment of Potato virus X TGBp3 is a major determinant of the protein intracellular trafficking. J Gen Virol 2005; 86:2379-2391. [PMID: 16033986 DOI: 10.1099/vir.0.80865-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Potato virus X (PVX) encodes three movement proteins, TGBp1, TGBp2 and TGBp3. The 8 kDa TGBp3 is a membrane-embedded protein that has an N-terminal hydrophobic sequence segment and a hydrophilic C terminus. TGBp3 mutants with deletions in the C-terminal hydrophilic region retain the ability to be targeted to cell peripheral structures and to support limited PVX cell-to-cell movement, suggesting that the basic TGBp3 functions are associated with its N-terminal transmembrane region. Fusion of green fluorescent protein to the TGBp3 N terminus abrogates protein activities in intracellular trafficking and virus movement. The intracellular transport of TGBp3 from sites of its synthesis in the rough endoplasmic reticulum (ER) to ER-derived peripheral bodies involves a non-conventional COPII-independent pathway. However, integrity of the C-terminal hydrophilic sequence is required for entrance to this non-canonical route.
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Affiliation(s)
- M V Schepetilnikov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia
| | - U Manske
- Institute of Plant Virology, Microbiology and Biosafety, Federal Biological Research Centre for Agriculture and Forestry, Messeweg 11/12, D-38104 Braunschweig, Germany
| | - A G Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia
| | - A A Zamyatnin
- Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences (SLU), PO Box 7080, S-750 07 Uppsala, Sweden
- Natural Sciences Center of A. M. Prokhorov, General Physics Institute, Russian Academy of Sciences, Bld L-2, 38 Vavilov Str., Moscow 119991, Russia
| | - J Schiemann
- Institute of Plant Virology, Microbiology and Biosafety, Federal Biological Research Centre for Agriculture and Forestry, Messeweg 11/12, D-38104 Braunschweig, Germany
| | - S Yu Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia
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32
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Carmen Herranz M, Sanchez-Navarro JA, Saurí A, Mingarro I, Pallás V. Mutational analysis of the RNA-binding domain of the Prunus necrotic ringspot virus (PNRSV) movement protein reveals its requirement for cell-to-cell movement. Virology 2005; 339:31-41. [PMID: 15963545 DOI: 10.1016/j.virol.2005.05.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 03/14/2005] [Accepted: 05/11/2005] [Indexed: 11/15/2022]
Abstract
The movement protein (MP) of Prunus necrotic ringspot virus (PNRSV) is required for cell-to-cell movement. MP subcellular localization studies using a GFP fusion protein revealed highly punctate structures between neighboring cells, believed to represent plasmodesmata. Deletion of the RNA-binding domain (RBD) of PNRSV MP abolishes the cell-to-cell movement. A mutational analysis on this RBD was performed in order to identify in vivo the features that govern viral transport. Loss of positive charges prevented the cell-to-cell movement even though all mutants showed a similar accumulation level in protoplasts to those observed with the wild-type (wt) MP. Synthetic peptides representing the mutants and wild-type RBDs were used to study RNA-binding affinities by EMSA assays being approximately 20-fold lower in the mutants. Circular dichroism analyses revealed that the secondary structure of the peptides was not significantly affected by mutations. The involvement of the affinity changes between the viral RNA and the MP in the viral cell-to-cell movement is discussed.
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Affiliation(s)
- Ma Carmen Herranz
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), UPV-CSIC, Avda. de los Naranjos, s/n, 46022, Valencia, Spain
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Verchot-Lubicz J. A new cell-to-cell transport model for Potexviruses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2005; 18:283-90. [PMID: 15828680 DOI: 10.1094/mpmi-18-0283] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In the last five years, we have gained significant insight into the role of the Potexvirus proteins in virus movement and RNA silencing. Potexviruses require three movement proteins, named triple gene block (TGB)p1, TGBp2, and TGBp3, and the viral coat protein (CP) to facilitate viral cell-to-cell and vascular transport. TGBp1 is a multifunctional protein that has RNA helicase activity, promotes translation of viral RNAs, increases plasmodesmal size exclusion limits, and suppresses RNA silencing. TGBp2 and TGBp3 are membrane-binding proteins. CP is required for genome encapsidation and forms ribonucleoprotein complexes along with TGBp1 and viral RNA. This review considers the functions of the TGB proteins, how they interact with each other and CP, and how silencing suppression might be linked to viral transport. A new model of the mechanism for Potexvirus transport is proposed.
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Affiliation(s)
- Jeanmarie Verchot-Lubicz
- Oklahoma State University, Department of Entomology and Plant Pathology, Stillwater, OK 74078, USA.
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Howard AR, Heppler ML, Ju HJ, Krishnamurthy K, Payton ME, Verchot-Lubicz J. Potato virus X TGBp1 induces plasmodesmata gating and moves between cells in several host species whereas CP moves only in N. benthamiana leaves. Virology 2004; 328:185-97. [PMID: 15464839 DOI: 10.1016/j.virol.2004.06.039] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2004] [Revised: 06/04/2004] [Accepted: 06/04/2004] [Indexed: 11/22/2022]
Abstract
Experiments were conducted to compare the plasmodesmal transport activities of Potato virus X (PVX) TGBp1 and coat protein (CP) in several plant species. Microinjection experiments indicated that TGBp1 gates plasmodesmata in Nicotiana tabacum leaves. These results support previous microinjection studies indicating that TGBp1 gates plasmodesmata in Nicotiana benthamiana and Nicotiana clevelandii leaves. To study protein movement, plasmids expressing the green fluorescent protein (GFP) gene fused to the PVX TGBp1 or CP genes were biolistically bombarded to leaves taken from four different PVX host species. GFP/TGBp1 moved between adjacent cells in N. tabacum, N. clevelandii, N. benthamiana, and Lycopersicon esculentum, whereas GFP/CP moved only in N. benthamiana leaves. Mutations m12 and m13 were introduced into the TGBp1 gene and both mutations eliminated TGBp1 ATPase active site motifs, inhibited PVX movement, reduced GFP/TGBp1 cell-to-cell movement in N. benthamiana leaves, and eliminated GFP/TGBp1 movement in N. tabacum, N. clevelandii, and L. esculentum leaves. GFP/TGBp1m13 formed aggregates in tobacco cells. The ability of GFP/CP and mutant GFP/TGBp1 fusion proteins to move in N. benthamiana and not in the other PVX host species suggests that N. benthamiana plants have a unique ability to promote protein intercellular movement.
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Affiliation(s)
- Amanda R Howard
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
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35
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Zamyatnin AA, Solovyev AG, Savenkov EI, Germundsson A, Sandgren M, Valkonen JPT, Morozov SY. Transient coexpression of individual genes encoded by the triple gene block of potato mop-top virus reveals requirements for TGBp1 trafficking. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2004; 17:921-30. [PMID: 15305613 DOI: 10.1094/mpmi.2004.17.8.921] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
TGBp1, TGBp2, and TGBp3, three plant virus movement proteins encoded by the "triple gene block" (TGB), may act in concert to facilitate cell-to-cell transport of viral RNA genomes. Transient expression of Potato mop-top virus (genus Pomovirus) movement proteins was used as a model to reconstruct interactions between TGB proteins. In bombarded epidermal cells of Nicotiana benthamiana, green fluorescent protein (GFP)-TGBp1 was distributed uniformly. However, in the presence of TGBp2 and TGBp3, GFP-TGBp1 was directed to intermediate bodies at the cell periphery, and to cell wall-embedded punctate bodies. Moreover, GFP-TGBp1 migrated into cells immediately adjacent to the bombarded cell. These data suggest that TGBp2 and TGBp3 mediate transport of GFP-TGBp1 to and through plasmodesmata. Mutagenesis of TGBp1 suggested that the NTPase and helicase activities of TGBp1 were not required for its transport to intermediate bodies directed by TGBp2 and TGBp3, but these activities were essential for the protein association with cell wall-embedded punctate bodies and translocation of TGBpl to neighboring cells. The C-terminal region of TGBp1 was critical for trafficking mediated by TGBp2 and TGBp3. Mutation analysis also suggested an involvement of the TGBp2 C-terminal region in interactions with TGBp1.
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Affiliation(s)
- Andrey A Zamyatnin
- Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences (SLU), SE-750 07 Uppsala, Sweden.
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36
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Heinlein M, Epel BL. Macromolecular Transport and Signaling Through Plasmodesmata. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 235:93-164. [PMID: 15219782 DOI: 10.1016/s0074-7696(04)35003-5] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Plasmodesmata (Pd) are channels in the plant cell wall that in conjunction with associated phloem form an intercellular communication network that supports the cell-to-cell and long-distance trafficking of a wide spectrum of endogenous proteins and ribonucleoprotein complexes. The trafficking of such macromolecules is of importance in the orchestration of non-cell autonomous developmental and physiological processes. Plant viruses encode movement proteins (MPs) that subvert this communication network to facilitate the spread of infection. These viral proteins thus represent excellent experimental keys for exploring the mechanisms involved in intercellular trafficking and communication via Pd.
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Affiliation(s)
- Manfred Heinlein
- Botanical Institute, University of Basel, Hebelstrasse 1, CH-4056 Basel, Switzerland
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37
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Morozov SY, Solovyev AG. Triple gene block: modular design of a multifunctional machine for plant virus movement. J Gen Virol 2003; 84:1351-1366. [PMID: 12771402 DOI: 10.1099/vir.0.18922-0] [Citation(s) in RCA: 259] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many plant virus genera encode a 'triple gene block' (TGB), a specialized evolutionarily conserved gene module involved in the cell-to-cell and long-distance movement of viruses. The TGB-based transport system exploits the co-ordinated action of three polypeptides to deliver viral genomes to plasmodesmata and to accomplish virus entry into neighbouring cells. Although data obtained on both the TGB and well-studied single protein transport systems clearly demonstrate that plant viruses employ host cell pathways for intra- and intercellular trafficking of genomic nucleic acids and proteins, there is no integral picture of the details of molecular events during TGB-mediated virus movement. Undoubtedly, understanding the molecular basis of the concerted action of TGB-encoded proteins in transporting viral genomes from cell to cell should provide new insights into the general principles of movement protein function. This review describes the structure, phylogeny and expression of TGB proteins, their roles in virus cell-to-cell movement and potential influence on host antiviral defences.
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Affiliation(s)
- Sergey Yu Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia
| | - Andrey G Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia
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38
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Gorshkova EN, Erokhina TN, Stroganova TA, Yelina NE, Zamyatnin AA, Kalinina NO, Schiemann J, Solovyev AG, Morozov SY. Immunodetection and fluorescent microscopy of transgenically expressed hordeivirus TGBp3 movement protein reveals its association with endoplasmic reticulum elements in close proximity to plasmodesmata. J Gen Virol 2003; 84:985-994. [PMID: 12655101 DOI: 10.1099/vir.0.18885-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The subcellular localization of the hydrophobic TGBp3 protein of Poa semilatent virus (PSLV, genus Hordeivirus) was studied in transgenic plants using fluorescent microscopy to detect green fluorescent protein (GFP)-tagged protein and immunodetection with monoclonal antibodies (mAbs) raised against the GFP-based fusion expressed in E. coli. In Western blot analysis, mAbs efficiently recognized the wild-type and GFP-fused PSLV TGBp3 proteins expressed in transgenic Nicotiana benthamiana, but failed to detect TGBp3 in hordeivirus-infected plants. It was found that PSLV TGBp3 and GFP-TGBp3 had a tendency to form large protein complexes of an unknown nature. Fractionation studies revealed that TGBp3 represented an integral membrane protein and probably co-localized with an endoplasmic reticulum-derived domain. Microscopy of epidermal cells in transgenic plants demonstrated that GFP-TGBp3 localized to cell wall-associated punctate bodies, which often formed pairs of opposing discrete structures that co-localized with callose, indicating their association with the plasmodesmata-enriched cell wall fields. After mannitol-induced plasmolysis of the leaf epidermal cells in the transgenic plants, TGBp3 appeared within the cytoplasm and not at cell walls. Although TGBp3-induced bodies were normally static, most of them became motile after plasmolysis and displayed stochastic motion in the cytoplasm.
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Affiliation(s)
- E N Gorshkova
- Department of Virology and A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia
| | - T N Erokhina
- M. M. Shemyakin & Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Str., Moscow 117997, Russia
| | - T A Stroganova
- Institute of Microbiology, Russian Academy of Sciences, 7 Prospect 60 Let Oktyabrya, Moscow 117811, Russia
| | - N E Yelina
- Department of Virology and A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia
| | - A A Zamyatnin
- Department of Virology and A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia
| | - N O Kalinina
- Department of Virology and A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia
| | - J Schiemann
- Institute of Plant Virology, Microbiology and Biosafety, Federal Biological Research Centre for Agriculture and Forestry, Messeweg 11/12, D-38104 Braunschweig, Germany
| | - A G Solovyev
- Department of Virology and A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia
| | - S Yu Morozov
- Department of Virology and A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia
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39
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Kalinina NO, Rakitina DV, Solovyev AG, Schiemann J, Morozov SY. RNA helicase activity of the plant virus movement proteins encoded by the first gene of the triple gene block. Virology 2002; 296:321-9. [PMID: 12069530 DOI: 10.1006/viro.2001.1328] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cell-to-cell and long-distance transport of some plant viruses requires coordinated action of three movement proteins encoded by triple gene block (TGB). The largest of TGB proteins, TGBp1, is a member of the superfamily I of DNA/RNA helicases and possesses a set of conserved helicase sequence motifs necessary for virus movement. A recombinant His-tagged form of TGBp1 of two hordeiviruses and potato virus X, a potexvirus, produced in Escherichia coli had unwinding activity on a partially duplexed RNA, but not DNA substrate. The helicase activity of these proteins was dependent on Mg2+ and ATP. The isolated C-terminal half of the PSLV TGBp1 retaining all helicase motifs was also able to unwind RNA duplex.
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Affiliation(s)
- N O Kalinina
- Department of Virology, Moscow State University, Moscow, Russia
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40
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Zamyatnin AA, Solovyev AG, Sablina AA, Agranovsky AA, Katul L, Vetten HJ, Schiemann J, Hinkkanen AE, Lehto K, Morozov SY. Dual-colour imaging of membrane protein targeting directed by poa semilatent virus movement protein TGBp3 in plant and mammalian cells. J Gen Virol 2002; 83:651-662. [PMID: 11842260 DOI: 10.1099/0022-1317-83-3-651] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The movement function of poa semilatent hordeivirus (PSLV) is mediated by the triple gene block (TGB) proteins, of which two, TGBp2 and TGBp3, are membrane proteins. TGBp3 is localized to peripheral bodies in the vicinity of the plasma membrane and is able to re-direct TGBp2 from the endoplasmic reticulum (ER) to the peripheral bodies. For imaging of TGBp3-mediated protein targeting, PSLV TGBp3 tagged with a red fluorescent protein (DsRed) was used. Coexpression of DsRed-TGBp3 with GFP targeted to the ER lumen (ER-GFP) demonstrated that ER-GFP was contained in typical ER structures and peripheral bodies formed by TGBp3 protein, suggesting an ER origin for these bodies. In transient coexpression with viral membrane proteins tagged with GFP, DsRed-TGBp3 directed to the peripheral bodies the homologous TGBp2 protein and two unrelated membrane proteins, the 6 kDa movement protein of beet yellows closterovirus and the putative movement protein encoded by the genome component 4 of faba bean necrotic yellows nanovirus. However, coexpression of TGBp3 with GFP derivatives targeted to the ER membranes by artificial hydrophobic tail sequences suggested that targeting to the ER membranes per se was not sufficient for TGBp3-directed protein trafficking to peripheral bodies. TGBp3-induced targeting of TGBp2 also occurred in mammalian cells, indicating the universal nature of the protein trafficking signals and the cotargeting mechanism.
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Affiliation(s)
- A A Zamyatnin
- A. N. Belozersky Institute of Physico-Chemical Biology and Department of Virology, Moscow State University, Moscow 119899, Russia1
| | - A G Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology and Department of Virology, Moscow State University, Moscow 119899, Russia1
| | - A A Sablina
- Institute of Carcinogenesis, Cancer Research Center, Moscow 115478, Russia2
| | - A A Agranovsky
- A. N. Belozersky Institute of Physico-Chemical Biology and Department of Virology, Moscow State University, Moscow 119899, Russia1
| | - L Katul
- Institute of Plant Virology, Microbiology and Biosafety, Federal Biological Research Centre for Agriculture and Forestry, Messeweg 11/12, D-38104 Braunschweig, Germany3
| | - H J Vetten
- Institute of Plant Virology, Microbiology and Biosafety, Federal Biological Research Centre for Agriculture and Forestry, Messeweg 11/12, D-38104 Braunschweig, Germany3
| | - J Schiemann
- Institute of Plant Virology, Microbiology and Biosafety, Federal Biological Research Centre for Agriculture and Forestry, Messeweg 11/12, D-38104 Braunschweig, Germany3
| | - A E Hinkkanen
- Department of Biochemistry and Pharmacy, Åbo Akademi University, 20521 Turku, Finland4
| | - K Lehto
- Department of Biology, University of Turku, 20500 Turku, Finland5
| | - S Yu Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology and Department of Virology, Moscow State University, Moscow 119899, Russia1
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