scholarly journals Conversion in the Requirement of Coat Protein in Cell-to-Cell Movement Mediated by the Cucumber Mosaic Virus Movement Protein

2001 ◽  
Vol 75 (17) ◽  
pp. 8045-8053 ◽  
Author(s):  
Hideaki Nagano ◽  
Kazuyuki Mise ◽  
Iwao Furusawa ◽  
Tetsuro Okuno
Keyword(s):  
Amino Acids ◽  
Coat Protein ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Movement Protein ◽  
Cell Movement ◽  
Plant Viruses ◽  
Brome Mosaic Virus ◽  
Viral Movement ◽  
Intercellular Movement

ABSTRACT Plant viruses have movement protein (MP) gene(s) essential for cell-to-cell movement in hosts. Cucumber mosaic virus (CMV) requires its own coat protein (CP) in addition to the MP for intercellular movement. Our present results using variants of both CMV and a chimeric Brome mosaic virus with the CMV MP gene revealed that CMV MP truncated in its C-terminal 33 amino acids has the ability to mediate viral movement independently of CP. Coexpression of the intact and truncated CMV MPs extremely reduced movement of the chimeric viruses, suggesting that these heterogeneous CMV MPs function antagonistically. Sequential deletion analyses of the CMV MP revealed that the dispensability of CP occurred when the C-terminal deletion ranged between 31 and 36 amino acids and that shorter deletion impaired the ability of the MP to promote viral movement. This is the first report that a region of MP determines the requirement of CP in cell-to-cell movement of a plant virus.

scholarly journals Role of the Alfalfa mosaic virus Movement Protein and Coat Protein in Virus Transport

2001 ◽  
Vol 14 (9) ◽  
pp. 1051-1062 ◽  
Author(s):  
Jesús A. Sánchez-Navarro ◽  
John F. Bol
Keyword(s):  
Amino Acids ◽  
Coat Protein ◽  
Mosaic Virus ◽  
Movement Protein ◽  
Alfalfa Mosaic Virus ◽  
Cell Movement ◽  
Brome Mosaic Virus ◽  
Tubular Structures ◽  
Wild Type ◽  
Virus Transport

The movement protein (MP) and coat protein (CP) encoded by Alfalfa mosaic virus (AMV) RNA 3 are both required for virus transport. RNA 3 vectors that expressed nonfused green fluorescent protein (GFP), MP:GPF fusions, or GFP:CP fusions were used to study the functioning of mutant MP and CP in protoplasts and plants. C-terminal deletions of up to 21 amino acids did not interfere with the function of the CP in cell-to-cell movement, although some of these mutations interfered with virion assembly. Deletion of the N-terminal 11 or C-terminal 45 amino acids did not interfere with the ability of MP to assemble into tubular structures on the protoplast surface. Additionally, N- or C-terminal deletions disrupted tubule formation. A GFP:CP fusion was targeted specifically into tubules consisting of a wild-type MP. All MP deletion mutants that showed cell-to-cell and systemic movement in plants were able to form tubular structures on the surface of protoplasts. Brome mosaic virus (BMV) MP did not support AMV transport. When the C-terminal 48 amino acids were replaced by the C-terminal 44 amino acids of the AMV MP, however, the BMV/AMV chimeric protein permitted wild-type levels of AMV transport. Apparently, the C terminus of the AMV MP, although dispensable for cell-to-cell movement, confers specificity to the transport process.

Natural isolates of Brome mosaic virus with the ability to move from cell to cell independently of coat protein

2005 ◽  
Vol 86 (4) ◽  
pp. 1201-1211 ◽  
Author(s):  
Atsushi Takeda ◽  
Wakako Nakamura ◽  
Nobumitsu Sasaki ◽  
Kaku Goto ◽  
Masanori Kaido ◽  
...  
Keyword(s):  
Coat Protein ◽  
Mosaic Virus ◽  
Mutational Analysis ◽  
Cell Movement ◽  
Plant Viruses ◽  
Brome Mosaic Virus ◽  
Single Amino Acid ◽  
In Planta ◽  
C Terminus ◽  
Natural Isolates

Brome mosaic virus (BMV) requires encapsidation-competent coat protein (CP) for cell-to-cell movement and the 3a movement protein (MP) is involved in determining the CP requirement for BMV movement. However, these conclusions have been drawn by using BMV strain M1 (BMV-M1) and a related strain. Here, the ability of the MPs of five other natural BMV strains to mediate the movement of BMV-M1 in the absence of CP was tested. The MP of BMV M2 strain (BMV-M2) efficiently mediated the movement of CP-deficient BMV-M1 and the MPs of two other strains functioned similarly to some extent. Furthermore, BMV-M2 itself moved between cells independently of CP, demonstrating that BMV-M1 and -M2 use different movement modes. Reassortment between CP-deficient BMV-M1 and -M2 showed the involvement of RNA3 in determining the CP requirement for cell-to-cell movement and the involvement of RNAs 1 and 2 in movement efficiency and symptom induction in the absence of CP. Spontaneous BMV MP mutants generated in planta that exhibited CP-independent movement were also isolated and analysed. Comparison of the nucleotide differences of the MP genes of BMV-M1, the natural strains and mutants capable of CP-independent movement, together with further mutational analysis of BMV-M1 MP, revealed that single amino acid differences at the C terminus of MP are sufficient to alter the requirement for CP in the movement of BMV-M1. Based on these findings, a possible virus strategy in which a movement mode is selected in plant viruses to optimize viral infectivity in plants is discussed.

scholarly journals Downregulation of the NbNACa1 Gene Encoding a Movement-Protein-Interacting Protein Reduces Cell-to-Cell Movement of Brome mosaic virus in Nicotiana benthamiana

2007 ◽  
Vol 20 (6) ◽  
pp. 671-681 ◽  
Author(s):  
Masanori Kaido ◽  
Yosuke Inoue ◽  
Yoshika Takeda ◽  
Kazuhiko Sugiyama ◽  
Atsushi Takeda ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Nicotiana Benthamiana ◽  
Fluorescent Protein ◽  
Movement Protein ◽  
Sequence Similarity ◽  
Microprojectile Bombardment ◽  
Cell Movement ◽  
Brome Mosaic Virus ◽  
Viral Movement

The 3a movement protein (MP) plays a central role in the movement of the RNA plant virus, Brome mosaic virus (BMV). To identify host factor genes involved in viral movement, a cDNA library of Nicotiana benthamiana, a systemic host for BMV, was screened with far-Western blotting using a recombinant BMV MP as probe. One positive clone encoded a protein with sequence similarity to the α chain of nascent-polypeptide-associated complex from various organisms, which is proposed to contribute to the fidelity of translocation of newly synthesized proteins. The orthologous gene from N. benthamiana was designated NbNACa1. The binding of NbNACa1 to BMV MP was confirmed in vivo with an agroinfiltration-immunoprecipitation assay. To investigate the involvement of NbNACa1 in BMV multiplication, NbNACa1-silenced (GSNAC) transgenic N. benthamiana plants were produced. Downregulation of NbNACa1 expression reduced virus accumulation in inoculated leaves but not in protoplasts. A microprojectile bombardment assay to monitor BMV-MP-assisted viral movement demonstrated reduced virus spread in GSNAC plants. The localization to the cell wall of BMV MP fused to green fluorescent protein was delayed in GSNAC plants. From these results, we propose that NbNACa1 is involved in BMV cell-to-cell movement through the regulation of BMV MP localization to the plasmodesmata.

scholarly journals P3N-PIPO Interacts with P3 via the Shared N-Terminal Domain To Recruit Viral Replication Vesicles for Cell-to-Cell Movement

2020 ◽  
Vol 94 (8) ◽  
Author(s):  
Mengzhu Chai ◽  
Xiaoyun Wu ◽  
Jiahui Liu ◽  
Yue Fang ◽  
Yameng Luan ◽  
...  
Keyword(s):  
Viral Replication ◽  
Mosaic Virus ◽  
Essential Role ◽  
Movement Protein ◽  
Cell Movement ◽  
Plant Viruses ◽  
Turnip Mosaic Virus ◽  
Limited Information ◽  
Intercellular Movement ◽  
Model Virus

ABSTRACT P3N-PIPO, the only dedicated movement protein (MP) of potyviruses, directs cylindrical inclusion (CI) protein from the cytoplasm to the plasmodesma (PD), where CI forms conical structures for intercellular movement. To better understand potyviral cell-to-cell movement, we further characterized P3N-PIPO using Turnip mosaic virus (TuMV) as a model virus. We found that P3N-PIPO interacts with P3 via the shared P3N domain and that TuMV mutants lacking the P3N domain of either P3N-PIPO or P3 are defective in cell-to-cell movement. Moreover, we found that the PIPO domain of P3N-PIPO is sufficient to direct CI to the PD, whereas the P3N domain is necessary for localization of P3N-PIPO to 6K2-labeled vesicles or aggregates. Finally, we discovered that the interaction between P3 and P3N-PIPO is essential for the recruitment of CI to cytoplasmic 6K2-containing structures and the association of 6K2-containing structures with PD-located CI inclusions. These data suggest that both P3N and PIPO domains are indispensable for potyviral cell-to-cell movement and that the 6K2 vesicles in proximity to PDs resulting from multipartite interactions among 6K2, P3, P3N-PIPO, and CI may also play an essential role in this process. IMPORTANCE Potyviruses include numerous economically important viruses that represent approximately 30% of known plant viruses. However, there is still limited information about the mechanism of potyviral cell-to-cell movement. Here, we show that P3N-PIPO interacts with and recruits CI to the PD via the PIPO domain and interacts with P3 via the shared P3N domain. We further report that the interaction of P3N-PIPO and P3 is associated with 6K2 vesicles and brings the 6K2 vesicles into proximity with PD-located CI structures. These results support the notion that the replication and cell-to-cell movement of potyviruses are processes coupled by anchoring viral replication complexes at the entrance of PDs, which greatly increase our knowledge of the intercellular movement of potyviruses.

scholarly journals The C terminus of the movement protein of Brome mosaic virus controls the requirement for coat protein in cell-to-cell movement and plays a role in long-distance movement

2004 ◽  
Vol 85 (6) ◽  
pp. 1751-1761 ◽  
Author(s):  
Atsushi Takeda ◽  
Masanori Kaido ◽  
Tetsuro Okuno ◽  
Kazuyuki Mise
Keyword(s):  
Coat Protein ◽  
Mosaic Virus ◽  
Movement Protein ◽  
Cell Movement ◽  
Brome Mosaic Virus ◽  
Wild Type ◽  
Long Distance ◽  
C Terminus ◽  
Mouth Disease Virus ◽  
Long Distance Movement

The 3a movement protein (MP) plays a central role in the movement of Brome mosaic virus (BMV). To identify the functional regions in BMV MP, 24 alanine-scanning (AS) MP mutants of BMV were constructed. Infectivity of the AS mutants in the host plant Chenopodium quinoa showed that the central region of BMV MP is important for viral movement and both termini of BMV MP have effects on the development of systemic symptoms. A green-fluorescent-protein-expressing RNA3-based BMV vector containing a 2A sequence from Foot-and-mouth disease virus was also constructed. Using this vector, two AS mutants that showed more efficient cell-to-cell movement than wild-type BMV were identified. The MPs of these two AS mutants, which have mutations at their C termini, mediated cell-to-cell movement independently of coat protein (CP), unlike wild-type BMV MP. Furthermore, a BMV mutant with a truncation in the C-terminal 42 amino acids of MP was also able to move from cell to cell without CP, but did not move systemically, even in the presence of CP. These results and an encapsidation analysis suggest that the C terminus of BMV MP is involved in the requirement for CP in cell-to-cell movement and plays a role in long-distance movement. Furthermore, the ability to spread locally and form virions is not sufficient for the long-distance movement of BMV. The roles of MP and CP in BMV movement are discussed.

scholarly journals Actin Cytoskeleton Is Involved in Targeting of a Viral Hsp70 Homolog to the Cell Periphery

2005 ◽  
Vol 79 (22) ◽  
pp. 14421-14428 ◽  
Author(s):  
Alexey I. Prokhnevsky ◽  
Valera V. Peremyslov ◽  
Valerian V. Dolja
Keyword(s):  
Actin Cytoskeleton ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Movement Protein ◽  
Fluorescent Proteins ◽  
Cell Movement ◽  
Plant Viruses ◽  
Cell Periphery ◽  
Virus Particles ◽  
Shock Proteins

ABSTRACT The cell-to-cell movement of plant viruses involves translocation of virus particles or nucleoproteins to and through the plasmodesmata (PDs). As we have shown previously, the movement of the Beet yellows virus requires the concerted action of five viral proteins including a homolog of cellular ∼70-kDa heat shock proteins (Hsp70h). Hsp70h is an integral component of the virus particles and is also found in PDs of the infected cells. Here we investigate subcellular distribution of Hsp70h using transient expression of Hsp70h fused to three spectrally distinct fluorescent proteins. We found that fluorophore-tagged Hsp70h forms motile granules that are associated with actin microfilaments, but not with microtubules. In addition, immobile granules were observed at the cell periphery. A pairwise appearance of these granules at the opposite sides of cell walls and their colocalization with the movement protein of Tobacco mosaic virus indicated an association of Hsp70h with PDs. Treatment with various cytoskeleton-specific drugs revealed that the intact actomyosin motility system is required for trafficking of Hsp70h in cytosol and its targeting to PDs. In contrast, none of the drugs interfered with the PD localization of Tobacco mosaic virus movement protein. Collectively, these findings suggest that Hsp70h is translocated and anchored to PDs in association with the actin cytoskeleton.

scholarly journals The Rate of Cell-to-Cell Movement in Squash of Cucumber Mosaic Virus Is Affected by Sequences of the Capsid Protein

1999 ◽  
Vol 12 (7) ◽  
pp. 628-632 ◽  
Author(s):  
Sek-Man Wong ◽  
Sharon Swee-Chin Thio ◽  
Michael H. Shintaku ◽  
Peter Palukaitis
Keyword(s):  
Amino Acids ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Capsid Protein ◽  
Cell Movement ◽  
Systemic Infection ◽  
Long Distance ◽  
Local Movement ◽  
Long Distance Movement

The M strain of cucumber mosaic virus (CMV) does not infect squash plants systemically and moves very slowly in inoculated cotyledons. Systemic infection and an increase in the rate of local movement were observed when amino acids 129 or 214 of the M-CMV capsid protein (CP) were altered to those present in the Fny strain of CMV. While the opposite alterations to the CP of Fny-CMV inhibited systemic infection of squash, they did not show the same effects on the rates of both cell-to-cell and long-distance movement. However, the ability of CMV to infect squash systemically was affected by the rate of cell-to-cell movement.

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