The Experts below are selected from a list of 34488 Experts worldwide ranked by ideXlab platform
Hiroshi Nyunoya - One of the best experts on this subject based on the ideXlab platform.
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altered subcellular localization of a tobacco membrane raft associated remorin protein by tobamovirus infection and transient expression of viral replication and Movement Proteins
Frontiers in Plant Science, 2018Co-Authors: Nobumitsu Sasaki, Hiroshi Nyunoya, Eita TakashimaAbstract:Remorins are plant specific Proteins found in plasma membrane microdomains (termed lipid or membrane rafts) and plasmodesmata. A potato remorin is reported to be involved in regulating negatively potexvirus Movement and plasmodesmal permeability. In this study, we isolated cDNAs of tobacco remorins (NtREMs) and examined roles of an NtREM in infection by tomato mosaic virus (ToMV). Subcellular localization analysis by using fluorescently tagged NtREM, ToMV, and viral replication and Movement Proteins indicated that virus infection and transient expression of the viral Proteins promoted the formation of NtREM aggregates by alteration of the subcellular distribution of NtREM, which was localized uniformly on the plasma membrane under normal conditions. NtREM aggregates were often observed to be associated closely with endoplasmic reticulum networks and also bodies of the 126K replication and Movement Proteins. The bimolecular fluorescence complementation assay indicated that NtREM might interact directly with the Movement protein on the plasma membrane and around plasmodesmata. In addition, transient overexpression of NtREM facilitated ToMV cell-to-cell Movement. Based on these results, we discuss possible roles of the tobacco remorin in tobamovirus Movement.
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Altered Subcellular Localization of a Tobacco Membrane Raft-Associated Remorin Protein by Tobamovirus Infection and Transient Expression of Viral Replication and Movement Proteins
Frontiers Media S.A., 2018Co-Authors: Nobumitsu Sasaki, Hiroshi Nyunoya, Eita TakashimaAbstract:Remorins are plant specific Proteins found in plasma membrane microdomains (termed lipid or membrane rafts) and plasmodesmata. A potato remorin is reported to be involved in negatively regulating potexvirus Movement and plasmodesmal permeability. In this study, we isolated cDNAs of tobacco remorins (NtREMs) and examined roles of an NtREM in infection by tomato mosaic virus (ToMV). Subcellular localization analysis using fluorescently tagged NtREM, ToMV, and viral replication and Movement Proteins (MPs) indicated that virus infection and transient expression of the viral Proteins promoted the formation of NtREM aggregates by altering the subcellular distribution of NtREM, which was localized uniformly on the plasma membrane under normal conditions. NtREM aggregates were often observed associated closely with endoplasmic reticulum networks and bodies of the 126K replication and MPs. The bimolecular fluorescence complementation assay indicated that NtREM might interact directly with the MP on the plasma membrane and around plasmodesmata. In addition, transient overexpression of NtREM facilitated ToMV cell-to-cell Movement. Based on these results, we discuss possible roles of the tobacco remorin in tobamovirus Movement
Sondra G. Lazarowitz - One of the best experts on this subject based on the ideXlab platform.
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Arabidopsis synaptotagmin SYTA regulates endocytosis and virus Movement protein cell-to-cell transport
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: Jennifer D. Lewis, Sondra G. LazarowitzAbstract:Synaptotagmins are calcium sensors that regulate synaptic vesicle exo/endocytosis. Thought to be exclusive to animals, they have recently been characterized in plants. We show that Arabidopsis synaptotagmin SYTA regulates endosome recycling and Movement protein (MP)-mediated trafficking of plant virus genomes through plasmodesmata. SYTA localizes to endosomes in plant cells and directly binds the distinct Cabbage leaf curl virus (CaLCuV) and Tobacco mosaic virus (TMV) cell-to-cell Movement Proteins. In a SYTA knockdown line, CaLCuV systemic infection is delayed, and cell-to-cell spread of TMV and CaLCuV Movement Proteins is inhibited. A dominant-negative SYTA mutant causes depletion of plasma membrane-derived endosomes, produces large intracellular vesicles attached to plasma membrane, and inhibits cell-to-cell trafficking of TMV and CaLCuV Movement Proteins, when tested in an Agrobacterium-based leaf expression assay. Our studies show that SYTA regulates endocytosis, and suggest that distinct virus Movement Proteins transport their cargos to plasmodesmata for cell-to-cell spread via an endocytic recycling pathway.
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nuclear export in plants use of geminivirus Movement Proteins for a cell based export assay
The Plant Cell, 1999Co-Authors: Brian M Ward, Sondra G. LazarowitzAbstract:The nuclear export of Proteins and RNAs has been studied in heterokaryons or by microinjecting test substrates into nuclei of HeLa cells or Xenopus oocytes. We have previously shown that the two Movement Proteins BR1 and BL1 encoded by the plant pathogenic squash leaf curl virus act in a coordinated manner to facilitate virus cell-to-cell Movement and that one of these (BR1) is a nuclear shuttle protein. By using a novel in vivo cell-based assay for nuclear export in which nuclear-localized BR1 is trapped by BL1 and redirected to the cortical cytoplasm, we demonstrate that residues 177 to 198 of BR1 contain a leucine-rich nuclear export signal (NES) of the type found in the Rev protein encoded by the human immunodeficiency virus and in Xenopus TFIIIA. We further show that the TFIIIA NES can functionally replace the NES of BR1 in both nuclear export and viral infectivity. These findings suggest that this basic pathway for nuclear export is highly conserved among plant and animal cells and in yeast.
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viral Movement Proteins as probes for intracellular and intercellular trafficking in plants
The Plant Cell, 1999Co-Authors: Sondra G. Lazarowitz, Roger N. BeachyAbstract:The ability of viruses to cross the cellulosic cell wall to propagate infection throughout a plant has been a long-standing puzzle in plant cell biology and virology. Contemplated from the perspective of the topology of the plant cell and the plant as an integrated structure of the differentiated
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Probing plant cell structure and function with viral Movement Proteins.
Current opinion in plant biology, 1999Co-Authors: Sondra G. LazarowitzAbstract:Virus-encoded Movement Proteins are the principal strategy by which all plant viruses counter the primary physical defense of the plant to infection — the cell wall — to produce systemic infection and disease. Our understanding of the how these Proteins act at the molecular and cellular level has increased enormously in the past decade and ushered in an exciting new era of plant virology as an approach to investigating plant cell structure and function. The earliest studies focused on how Movement Proteins interacted with plasmodesmata, and were an important element in demonstrating the dynamic nature of these intercellular channels. Current efforts are focused on the role of Movement Proteins in coordinating the replication of viral genomes and the vectorial Movement of the progeny genomes through the infected cell, as well as into adjacent cells. Movement Proteins are thus providing unique approaches to unravel the fundamental mechanisms by which macromolecular transport is directed and integrated within and between plant cells.
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The geminivirus BL1 Movement protein is associated with endoplasmic reticulum-derived tubules in developing phloem cells.
Journal of virology, 1997Co-Authors: Brian M Ward, Sondra G. Lazarowitz, Richard Medville, Robert TurgeonAbstract:Plant viruses encode Movement Proteins that are essential for systemic infection of their host but dispensable for replication and encapsidation. BL1, one of the two Movement Proteins encoded by the bipartite geminivirus squash leaf curl virus, was immunolocalized to unique approximately 40-nm tubules that extended up to and across the walls of procambial cells in systemically infected pumpkin leaves. These tubules were not found in procambial cells from pumpkin seedlings inoculated with BL1 mutants that are defective in Movement. The tubules also specifically stained with antisera to binding protein (BiP), indicating that they were derived from the endoplasmic reticulum. Independent confirmation of this endoplasmic reticulum association was obtained by subcellular fractionation studies in which BL1 was localized to fractions that contained both endoplasmic reticulum membranes and BiP. Thus, squash leaf curl virus appears to recruit the endoplasmic reticulum as a conduit for cell-to-cell Movement of the viral genome.
William J Lucas - One of the best experts on this subject based on the ideXlab platform.
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plant viral Movement Proteins agents for cell to cell trafficking of viral genomes
Virology, 2006Co-Authors: William J LucasAbstract:Plants viruses spread throughout their hosts using a number of pathways, the most common being Movement cell to cell through plasmodesmata (PD), unique intercellular organelles of the plant kingdom, and between organs by means of the vascular system. Pioneering studies on plant viruses revealed that PD allow the cell-to-cell trafficking of virally encoded Proteins, termed the Movement Proteins (MPs). This non-cell-autonomous protein (NCAP) pathway is similarly employed by the host to traffic macromolecules. Viral MPs bind RNA/DNA in a sequence nonspecific manner to form nucleoprotein complexes (NPC). Host Proteins are then involved in the delivery of MPs and NPC to the PD orifice, and a role for the cytoskeleton has been implicated. Trafficking of NCAPs through the PD structure involves three steps in which the MP: (a) interacts with a putative PD docking complex, (b) induces dilation in the PD microchannels, and (c) binds to an internal translocation system for delivery into the neighboring cytoplasm. Viral genera that use this NCAP pathway have evolved a combination of a MP and ancillary Proteins that work in concert to enable the formation of a stable NPC that can compete with endogenous NCAPs for the PD trafficking machinery. Incompatible MP-host protein interactions may underlie observed tissue tropisms and restricted infection domains. These pivotal discoveries are discussed in terms of the need to develop a more comprehensive understanding of the (a) three-dimensional structure of MPs, (b) PD supramolecular complex, and (c) host Proteins involved in this cell-to-cell trafficking process.
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Phosphorylation of viral Movement Proteins – regulation of cell-to-cell trafficking
Trends in microbiology, 2001Co-Authors: Jung-youn Lee, William J LucasAbstract:Abstract In plants, Proteins and nucleoprotein complexes can traffic from cell to cell, via plasmodesmata. Studies based on viral Movement Proteins (MP) have revealed that such trafficking events are likely to be regulated at the level of protein phosphorylation. Plasmodesmal-associated protein kinases could play a central role in plant defense, in addition to regulating the translatability of endogenous MP–mRNA complexes that function at a supracellular level.
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phosphorylation of viral Movement Proteins regulation of cell to cell trafficking
Trends in Microbiology, 2001Co-Authors: Jung-youn Lee, William J LucasAbstract:Abstract In plants, Proteins and nucleoprotein complexes can traffic from cell to cell, via plasmodesmata. Studies based on viral Movement Proteins (MP) have revealed that such trafficking events are likely to be regulated at the level of protein phosphorylation. Plasmodesmal-associated protein kinases could play a central role in plant defense, in addition to regulating the translatability of endogenous MP–mRNA complexes that function at a supracellular level.
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plant paralog to viral Movement protein that potentiates transport of mrna into the phloem
Science, 1999Co-Authors: Beatriz Xoconostlecazares, Yu Xiang, Roberto Ruizmedrano, Hongli Wang, Jan Monzer, K C Mcfarland, Vincent R Franceschi, William J LucasAbstract:CmPP16 from Cucurbita maxima was cloned and the protein was shown to possess properties similar to those of viral Movement Proteins. CmPP16 messenger RNA (mRNA) is present in phloem tissue, whereas protein appears confined to sieve elements (SE). Microinjection and grafting studies revealed that CmPP16 moves from cell to cell, mediates the transport of sense and antisense RNA, and moves together with its mRNA into the SE of scion tissue. CmPP16 possesses the characteristics that are likely required to mediate RNA delivery into the long-distance translocation stream. Thus, RNA may move within the phloem as a component of a plant information superhighway.
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Bean Dwarf Mosaic Geminivirus Movement Proteins Recognize DNA in a Form- and Size-Specific Manner
Cell, 1998Co-Authors: Maria R Rojas, William J Lucas, Amine O. Noueiry, Robert L. GilbertsonAbstract:Plant viral Movement Proteins mediate the cell-to-cell Movement of nucleic acids. This involves either a direct interaction between the viral Movement protein and the nucleic acid or an indirect interaction involving host factors. The bipartite geminiviruses possess two Movement Proteins, BV1 and BC1, that coordinate Movement of viral DNA across nuclear and plasmodesmal boundaries, respectively. Here, we demonstrate that both BV1 and BC1 interact directly with DNA and, in addition, that they have the unique property to recognize DNA on the basis of form and size rather than sequence. This is a novel feature for plant virus Movement Proteins and raises the possibility that BV1 and BC1 may be determinants of genome size in the bipartite geminiviruses.
Manfred Heinlein - One of the best experts on this subject based on the ideXlab platform.
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Constriction of endoplasmic reticulum tubules by the viral Movement protein BMB2 is associated with local BMB2 anchorage at constriction sites.
Plant signaling & behavior, 2020Co-Authors: Ekaterina A Lazareva, Manfred Heinlein, Valerian V. Dolja, Alexander A Lezzhov, S.y. Morozov, Andrey G. SolovyevAbstract:Plant virus-encoded Movement Proteins (MPs) interact with endoplasmic reticulum (ER) membranes, the cytoskeleton, and plasmodesmata (PD) to mediate intracellular delivery of the virus genome to PD ...
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similarities in intracellular transport of plant viral Movement Proteins bmb2 and tgb3
Journal of General Virology, 2017Co-Authors: Ekaterina A Lazareva, Manfred Heinlein, Alexander A Lezzhov, S A Golyshev, Sergey Y Morozov, A G SolovyevAbstract:The cell-to-cell transport of many plant viruses through plasmodesmata requires viral Movement Proteins (MPs) encoded by a ‘triple gene block’ (TGB) and termed TGB1, TGB2 and TGB3. TGB3 is a small integral membrane protein that contains subcellular targeting signals and directs both TGB2 and the helicase domain-containing TGB1 protein to plasmodesmata-associated structures. Recently, we described a ‘binary Movement block’ (BMB) coding for two MPs, BMB1 and BMB2. The BMB2 protein associates with endoplasmic reticulum (ER) membranes, accumulates at plasmodesmata-associated membrane bodies and directs the BMB1 helicase to these structures. TGB3 transport to cell peripheral bodies was previously shown to bypass the secretory pathway and involve a non-conventional mechanism. Here, we provide evidence that the intracellular transport of both poa semilatent virus TGB3 and hibiscus green spot virus BMB2 to plasmodesmata-associated sites can occur via lateral translocation along the ER membranes. Agrobacterium-mediated transient co-expression in Nicotiana benthamiana leaves revealed that green fluorescent protein (GFP)-fused actin-binding domains of Arabidopsis fimbrin (ABD2–GFP) and mouse talin (TAL–GFP) inhibited the subcellular targeting of TGB3 and BMB2 to plasmodesmata-associated bodies, which resulted in TGB3 and BMB2 accumulation in the cytoplasm in association with aberrant ER structures. Inhibition of COPII budding complex formation by the expression of a dominant-negative mutant of the small GTPase Sar1 had no detectable effect on BMB2 subcellular targeting, which therefore could occur without exit from the ER in COPII transport vesicles. Collectively, the presented data support the current view that plant viral MPs exploit the ER:actin network for their intracellular transport.
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Manipulation of plant host susceptibility: an emerging role for viral Movement Proteins?
Frontiers in Plant Science, 2012Co-Authors: Khalid Amari, Franck Vazquez, Manfred HeinleinAbstract:Viruses encode viral suppressors of RNA silencing (VSRs) to counteract RNA silencing, a major antiviral defense response in plants. Recent studies indicate a role of virus-derived siRNAs in manipulating the expression of specific host genes and that certain plant viral Movement Proteins (MPs) can act as viral enhancers of RNA silencing (VERs) by stimulating the spread of silencing between cells. This suggests that viruses have evolved complex responses capable to efficiently hijack the host RNA silencing machinery to their own advantage. We draw here a dynamic model of the interaction of plant viruses with the silencing machinery during invasion of the host. The model proposes that cells at the spreading front of infection, where infection starts from zero and the VSR levels are supposedly low, represent potential sites for viral manipulation of host gene expression by using virus- and host-derived small RNAs. Viral MPs may facilitate the spread of silencing to produce a wave of small RNA-mediated gene expression changes ahead of the infection to increase host susceptibility. When experimentally ascertained, this hypothetical model will call for re-defining viral Movement and the function of viral MPs.
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Cellular pathways for viral transport through plasmodesmata
Protoplasma, 2011Co-Authors: Annette Niehl, Manfred HeinleinAbstract:Plant viruses use plasmodesmata (PD) to spread infection between cells and systemically. Dependent on viral species, Movement through PD can occur in virion or non-virion form, and requires different mechanisms for targeting and modification of the pore. These mechanisms are supported by viral Movement Proteins and by other virus-encoded factors that interact among themselves and with plant cellular components to facilitate virus Movement in a coordinated and regulated fashion.
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a family of plasmodesmal Proteins with receptor like properties for plant viral Movement Proteins
PLOS Pathogens, 2010Co-Authors: Khalid Amari, Emmanuel Boutant, Christina Hofmann, Corinne Schmittkeichinger, Lourdes Fernandezcalvino, Pascal Didier, Alexander Lerich, Jerome Mutterer, Carole L Thomas, Manfred HeinleinAbstract:Plasmodesmata (PD) are essential but poorly understood structures in plant cell walls that provide symplastic continuity and intercellular communication pathways between adjacent cells and thus play fundamental roles in development and pathogenesis. Viruses encode Movement Proteins (MPs) that modify these tightly regulated pores to facilitate their spread from cell to cell. The most striking of these modifications is observed for groups of viruses whose MPs form tubules that assemble in PDs and through which virions are transported to neighbouring cells. The nature of the molecular interactions between viral MPs and PD components and their role in viral Movement has remained essentially unknown. Here, we show that the family of PD-located Proteins (PDLPs) promotes the Movement of viruses that use tubule-guided Movement by interacting redundantly with tubule-forming MPs within PDs. Genetic disruption of this interaction leads to reduced tubule formation, delayed infection and attenuated symptoms. Our results implicate PDLPs as PD Proteins with receptor-like properties involved the assembly of viral MPs into tubules to promote viral Movement.
Vicente Pallás - One of the best experts on this subject based on the ideXlab platform.
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A conserved motif in three viral Movement Proteins from different genera is required for host factor recruitment and cell-to-cell Movement
Scientific reports, 2020Co-Authors: José A. Navarro, Marta Serra-soriano, Lorena Corachán-valencia, Vicente PallásAbstract:Due to their minimal genomes, plant viruses are forced to hijack specific cellular pathways to ensure host colonization, a condition that most frequently involves physical interaction between viral and host Proteins. Among putative viral interactors are the Movement Proteins, responsible for plasmodesma gating and genome binding during viral transport. Two of them, DGBp1 and DGBp2, are required for alpha-, beta- and gammacarmovirus cell-to-cell Movement, but the number of DGBp-host interactors identified at present is limited. By using two different approaches, yeast two-hybrid and bimolecular fluorescence complementation assays, we found three Arabidopsis factors, eIF3g1, RPP3A and WRKY36, interacting with DGBp1s from each genus mentioned above. eIF3g1 and RPP3A are mainly involved in protein translation initiation and elongation phases, respectively, while WRKY36 belongs to WRKY transcription factor family, important regulators of many defence responses. These host Proteins are not expected to be associated with viral Movement, but knocking out WRKY36 or silencing either RPP3A or eIF3g1 negatively affected Arabidopsis infection by Turnip crinkle virus. A highly conserved FNF motif at DGBp1 C-terminus was required for protein-protein interaction and cell-to-cell Movement, suggesting an important biological role.
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the functional analysis of distinct tospovirus Movement Proteins nsm reveals different capabilities in tubule formation cell to cell and systemic virus Movement among the tospovirus species
Virus Research, 2017Co-Authors: Mikhail Oliveira Leastro, Vicente Pallás, Renato O Resende, J A SancheznavarroAbstract:The lack of infectious tospovirus clones to address reverse genetic experiments has compromised the functional analysis of viral Proteins. In the present study we have performed a functional analysis of the Movement Proteins (NSM) of four tospovirus species Bean necrotic mosaic virus (BeNMV), Chrysanthemum stem necrosis virus (CSNV), Tomato chlorotic spot virus (TCSV) and Tomato spotted wilt virus (TSWV), which differ biologically and molecularly, by using the Alfalfa mosaic virus (AMV) model system. All NSM Proteins were competent to: i) support the cell-to-cell and systemic transport of AMV, ii) generate tubular structures on infected protoplast and iii) transport only virus particles. However, the NSM of BeNMV (one of the most phylogenetically distant species) was very inefficient to support the systemic transport. Deletion assays revealed that the C-terminal region of the BeNMV NSM, but not that of the CSNV, TCSV and TSWV NSM Proteins, was dispensable for cell-to-cell transport, and that all the non-functional C-terminal NSM mutants were unable to generate tubular structures. Bimolecular fluorescence complementation analysis revealed that the C-terminus of the BeNMV NSM was not required for the interaction with the cognate nucleocapsid protein, showing a different protein organization when compared with other Movement Proteins of the ‘30K family’. Overall, our results revealed clearly differences in functional aspects among Movement Proteins from divergent tospovirus species that have a distinct biological behavior.
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Plant Virus Cell-to-Cell Movement Is Not Dependent on the Transmembrane Disposition of Its Movement Protein
Journal of virology, 2009Co-Authors: Luis Martínez-gil, Vicente Pallás, Jesús A. Sánchez-navarro, Antonio Cruz, Jesús Pérez-gil, Ismael MingarroAbstract:The cell-to-cell transport of plant viruses depends on one or more virus-encoded Movement Proteins (MPs). Some MPs are integral membrane Proteins that interact with the membrane of the endoplasmic reticulum, but a detailed understanding of the interaction between MPs and biological membranes has been lacking. The cell-to-cell Movement of the Prunus necrotic ringspot virus (PNRSV) is facilitated by a single MP of the 30K superfamily. Here, using a myriad of biochemical and biophysical approaches, we show that the PNRSV MP contains only one hydrophobic region (HR) that interacts with the membrane interface, as opposed to being a transmembrane protein. We also show that a proline residue located in the middle of the HR constrains the structural conformation of this region at the membrane interface, and its replacement precludes virus Movement. Plant viruses encode Movement Proteins (MPs) that mediate the intra- and intercellular spread of the viral genome via plasmodesmata, membranous channels that traverse the walls of plant cells and enable intercellular transport and communication. There is a range of diversity in the number and type of viral Proteins required for viral Movement (21). Research on tobacco mosaic virus (TMV) has played a leading role in understanding MP activity (2). The genome of TMV encodes a single 30-kDa multidomain protein, the namesake of the 30K superfamily (7). Viral RNA is associated with the membrane of the endoplasmic reticulum (ER) and microtubules in the presence of this MP (23, 30).
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RNA-binding properties and membrane insertion of Melon necrotic spot virus (MNSV) double gene block Movement Proteins.
Virology, 2006Co-Authors: José Antonio Navarro, Ainhoa Genovés, Jose Climent, Ana Saurí, Ismael Mingarro, Luis Martinez, Vicente PallásAbstract:Abstract Advances in structural and biochemical properties of carmovirus Movement Proteins (MPs) have only been obtained in p7 and p9 from Carnation mottle virus (CarMV) . Alignment of carmovirus MPs revealed a low conservation of amino acid identity but interestingly, similarity was elevated in regions associated with the functional secondary structure elements reported for CarMV which were conserved in all studied Proteins. Nevertheless, some differential features in relation with CarMV MPs were identified in those from Melon necrotic virus (MNSV) (p7A and p7B). p7A was a soluble non-sequence specific RNA-binding protein, but unlike CarMV p7, its central region alone could not account for the RNA-binding properties of the entire protein. In fact, a 22-amino acid synthetic peptide whose sequence corresponds to this central region rendered an apparent dissociation constant ( K d ) significantly higher than that of the corresponding entire protein (9 mM vs. 0.83–25.7 μM). This p7A-derived peptide could be induced to fold into an alpha-helical structure as demonstrated for other carmovirus p7-like Proteins. Additionally, in vitro fractionation of p7B transcription/translation mixtures in the presence of ER-derived microsomal membranes strongly suggested that p7B is an integral membrane protein. Both characteristics of these two small MPs forming the double gene block (DGB) of MNSV are discussed in the context of the intra- and intercellular Movement of carmovirus.