scholarly journals Raspberry leaf blotch virus, a putative new member of the genus Emaravirus, encodes a novel genomic RNA

2012 ◽  
Vol 93 (2) ◽  
pp. 430-437 ◽  
Author(s):  
Wendy J. McGavin ◽  
Carolyn Mitchell ◽  
Peter J. A. Cock ◽  
Kathryn M. Wright ◽  
Stuart A. MacFarlane
Keyword(s):  
Fluorescent Protein ◽  
Movement Protein ◽  
Rna Virus ◽  
Sequence Similarity ◽  
Cell Movement ◽  
Glycoprotein Precursor ◽  
Peripheral Cell ◽  
Leaf Blotch ◽  
Single Protein ◽  
Sequence Similarities

A new, segmented, negative-strand RNA virus with morphological and sequence similarities to other viruses in the genus Emaravirus was discovered in raspberry plants exhibiting symptoms of leaf blotch disorder, a disease previously attributed to the eriophyid raspberry leaf and bud mite (Phyllocoptes gracilis). The virus, tentatively named raspberry leaf blotch virus (RLBV), has five RNAs that each potentially encode a single protein on the complementary strand. RNAs 1, 2 and 3 encode, respectively, a putative RNA-dependent RNA polymerase, a glycoprotein precursor and the nucleocapsid. RNA4 encodes a protein with sequence similarity to proteins of unknown function that are encoded by the genomes of other emaraviruses. When expressed transiently in plants fused to green or red fluorescent protein, the RLBV P4 protein localized to the peripheral cell membrane and to punctate spots in the cell wall. These spots co-localized with GFP-tagged tobacco mosaic virus 30K cell-to-cell movement protein, which is itself known to associate with plasmodesmata. These results suggest that the P4 protein may be a movement protein for RLBV. The fifth RLBV RNA, encoding the P5 protein, is unique among the sequenced emaraviruses. The amino acid sequence of the P5 protein does not suggest any potential function; however, when expressed as a GFP fusion, it localized as small aggregates in the cytoplasm near to the periphery of the cell.

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 Fig mosaic emaravirus p4 protein is involved in cell-to-cell movement

2013 ◽  
Vol 94 (3) ◽  
pp. 682-686 ◽  
Author(s):  
Kazuya Ishikawa ◽  
Kensaku Maejima ◽  
Ken Komatsu ◽  
Osamu Netsu ◽  
Takuya Keima ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Laser Scanning ◽  
Movement Protein ◽  
Rna Virus ◽  
Cell Movement ◽  
Plant Cells ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Series Of Experiments ◽  
Fig Mosaic Virus

Fig mosaic virus (FMV), a member of the newly formed genus Emaravirus, is a segmented negative-strand RNA virus. Each of the six genomic FMV segments contains a single ORF: that of RNA4 encodes the protein p4. FMV-p4 is presumed to be the movement protein (MP) of the virus; however, direct experimental evidence for this is lacking. We assessed the intercellular distribution of FMV-p4 in plant cells by confocal laser scanning microscopy and we found that FMV-p4 was localized to plasmodesmata and to the plasma membrane accompanied by tubule-like structures. A series of experiments designed to examine the movement functions revealed that FMV-p4 has the capacity to complement viral cell-to-cell movement, prompt GFP diffusion between cells, and spread by itself to neighbouring cells. Altogether, our findings demonstrated that FMV-p4 shares several properties with other viral MPs and plays an important role in cell-to-cell movement.

scholarly journals RNA1-Independent Replication and GFP Expression from Tomato marchitez virus Isolate M Cloned cDNA

2016 ◽  
Vol 106 (5) ◽  
pp. 500-509 ◽  
Author(s):  
I. Ferriol ◽  
M. Turina ◽  
E. J. Zamora-Macorra ◽  
B. W. Falk
Keyword(s):  
Fluorescent Protein ◽  
Rna Virus ◽  
Cell Movement ◽  
Full Length ◽  
Wild Type Virus ◽  
Cdna Clones ◽  
Genomic Rna ◽  
Positive Strand Rna Virus ◽  
Green Fluorescent ◽  
Positive Strand Rna

Tomato marchitez virus (ToMarV; synonymous with Tomato apex necrosis virus) is a positive-strand RNA virus in the genus Torradovirus within the family Secoviridae. ToMarV is an emergent whitefly-transmitted virus that causes important diseases in tomato (Solanum lycopersicum) in Mexico. Here, the genome sequence of the ToMarV isolate M (ToMarV-M) was determined. We engineered full-length cDNA clones of the ToMarV-M genomic RNA (RNA1 and RNA2), separately, into a binary vector. Coinfiltration of both triggered systemic infections in Nicotiana benthamiana, tomato, and tomatillo (Physalis philadelphica) plants and recapitulated the biological activity of the wild-type virus. The viral progeny generated from tomato and tomatillo plants were transmissible by the whitefly Bemisia tabaci biotype B. Also, we assessed whether these infectious clones could be used for screening tomato cultivars for resistance to ToMarV and our results allowed us to differentiate resistant and susceptible tomato lines. We demonstrated that RNA1 of ToMarV-M is required for the replication of RNA2, and it can replicate independently of RNA2. From this, ToMarV-M RNA2 was used to express the green fluorescent protein in N. benthamiana plants, which allowed us to track cell-to-cell movement. The construction of full-length infectious cDNA clones of ToMarV-M provides an excellent tool to investigate virus–host–vector interactions and elucidate the functions of torradovirus-encoded proteins or the mechanisms of replication of torradovirus genomic RNA.

scholarly journals Grapevine Fanleaf Virus Replication Occurs on Endoplasmic Reticulum-Derived Membranes

2002 ◽  
Vol 76 (17) ◽  
pp. 8808-8819 ◽  
Author(s):  
C. Ritzenthaler ◽  
C. Laporte ◽  
F. Gaire ◽  
P. Dunoyer ◽  
C. Schmitt ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Virus Replication ◽  
Fluorescent Protein ◽  
De Novo ◽  
Rna Virus ◽  
Lipid Synthesis ◽  
Cell Movement ◽  
Brefeldin A ◽  
Cell Periphery ◽  
Green Fluorescent

ABSTRACT Infection by Grapevine fanleaf nepovirus (GFLV), a bipartite RNA virus of positive polarity belonging to the Comoviridae family, causes extensive cytopathic modifications of the host endomembrane system that eventually culminate in the formation of a perinuclear “viral compartment.” We identified by immunoconfocal microscopy this compartment as the site of virus replication since it contained the RNA1-encoded proteins necessary for replication, newly synthesized viral RNA, and double-stranded replicative forms. In addition, by using transgenic T-BY2 protoplasts expressing green fluorescent protein in the endoplasmic reticulum (ER) or in the Golgi apparatus (GA), we could directly show that GFLV replication induced a depletion of the cortical ER, together with a condensation and redistribution of ER-derived membranes, to generate the viral compartment. Brefeldin A, a drug known to inhibit vesicle trafficking between the GA and the ER, was found to inhibit GFLV replication. Cerulenin, a drug inhibiting de novo synthesis of phospholipids, also inhibited GFLV replication. These observations imply that GFLV replication depends both on ER-derived membrane recruitment and on de novo lipid synthesis. In contrast to proteins involved in viral replication, the 2B movement protein and, to a lesser extent, the 2C coat protein were not confined to the viral compartment but were transported toward the cell periphery, a finding consistent with their role in cell-to-cell movement of virus particles.

scholarly journals Experimental and bioinformatic evidence that raspberry leaf blotch emaravirus P4 is a movement protein of the 30K superfamily

2013 ◽  
Vol 94 (9) ◽  
pp. 2117-2128 ◽  
Author(s):  
Chulang Yu ◽  
David G. Karlin ◽  
Yuwen Lu ◽  
Kathryn Wright ◽  
Jianping Chen ◽  
...  
Keyword(s):  
Movement Protein ◽  
Triple Gene Block ◽  
Tobacco Rattle Virus ◽  
Cell Movement ◽  
Potato Virus X ◽  
Plant Viruses ◽  
Membrane Association ◽  
Leaf Blotch ◽  
Viral Movement Protein ◽  
Gene Block

Emaravirus is a recently described genus of negative-strand RNA plant viruses. Emaravirus P4 protein localizes to plasmodesmata, suggesting that it could be a viral movement protein (MP). In the current study, we showed that the P4 protein of raspberry leaf blotch emaravirus (RLBV) rescued the cell-to-cell movement of a defective potato virus X (PVX) that had a deletion mutation in the triple gene block 1 movement-associated protein. This demonstrated that RLBV P4 is a functional MP. Sequence analyses revealed that P4 is a distant member of the 30K superfamily of MPs. All MPs of this family contain two highly conserved regions predicted to form β-strands, namely β1 and β2. We explored by alanine mutagenesis the role of two residues of P4 (Ile106 and Asp127) located in each of these strands. We also made the equivalent substitutions in the 29K MP of tobacco rattle virus, another member of the 30K superfamily. All substitutions abolished the ability to complement PVX movement, except for the I106A substitution in the β1 region of P4. This region has been shown to mediate membrane association of 30K MPs; our results show that it is possible to make non-conservative substitutions of a well-conserved aliphatic residue within β1 without preventing the membrane association or movement function of P4.

scholarly journals Tobamoviral Movement Protein Transiently Expressed in a Single Epidermal Cell Functions Beyond Multiple Plasmodesmata and Spreads Multicellularly in an Infection-Coupled Manner

2001 ◽  
Vol 14 (2) ◽  
pp. 126-134 ◽  
Author(s):  
Atsushi Tamai ◽  
Tetsuo Meshi
Keyword(s):  
Mosaic Virus ◽  
Fluorescent Protein ◽  
Movement Protein ◽  
Microprojectile Bombardment ◽  
Cell Movement ◽  
Tomato Mosaic Virus ◽  
Protein Variant ◽  
Minute Amount ◽  
Cell Functions ◽  
Infected Cells

Cell-to-cell movement of a plant virus requires expression of the movement protein (MP). It has not been fully elucidated, however, how the MP functions in primary infected cells. With the use of a microprojectile bombardment-mediated DNA infection system for Tomato mosaic virus (ToMV), we found that the cotransfected ToMV MP gene exerts its effects in the initially infected cells and in their surrounding cells to achieve multicellular spread of movement-defective ToMV. Five other tobamoviral MPs examined also transcomplemented the movement-defective phenotype of ToMV, but the Cucumber mosaic virus 3a MP did not. Together with the cell-to-cell movement of the mutant virus, a fusion between the MP and an enhanced green fluorescent protein variant (EGFP) expressed in trans was distributed multicellularly and localized primarily in plasmodesmata between infected cells. In contrast, in noninfected sites the MP-EGFP fusion accumulated predominantly inside the bombarded cells as irregularly shaped aggregates, and only a minute amount of the fusion was found in plasmodesmata. Thus, the behavior of ToMV MP is greatly modulated in the presence of a replicating virus and it is highly likely that the MP spreads in the infection sites, coordinating with the cell-to-cell movement of the viral genome.

scholarly journals Mex67p of Schizosaccharomyces pombeInteracts with Rae1p in Mediating mRNA Export

2000 ◽  
Vol 20 (23) ◽  
pp. 8767-8782 ◽  
Author(s):  
Jin Ho Yoon ◽  
Dona C. Love ◽  
Anjan Guhathakurta ◽  
John A. Hanover ◽  
Ravi Dhar
Keyword(s):  
Nuclear Export ◽  
Rna Binding ◽  
Fluorescent Protein ◽  
Synthetic Lethality ◽  
Sequence Similarity ◽  
Mrna Export ◽  
Nuclear Periphery ◽  
Nuclear Pore ◽  
Multicopy Suppressor ◽  
Accessory Factor

ABSTRACT We identified the Schizosaccharomyces pombe mex67 gene (spmex67) as a multicopy suppressor of rae1-167 nup184-1 synthetic lethality and the rae1-167 tsmutation. spMex67p, a 596-amino-acid-long protein, has considerable sequence similarity to the Saccharomyces cerevisiae Mex67p (scMex67p) and human Tap. In contrast toscMEX67, spmex67 is essential for neither growth nor nuclear export of mRNA. However, an spmex67 null mutation (Δmex67) is synthetically lethal with therae1-167 mutation and accumulates poly(A)+ RNA in the nucleus. We identified a central region (149 to 505 amino acids) within spMex67p that associates with a complex containing Rae1p that complements growth and mRNA export defects of therae1-167 Δmex67 synthetic lethality. This region is devoid of RNA-binding, N-terminal nuclear localization, and the C-terminal nuclear pore complex-targeting regions. The (149–505)-green fluorescent protein (GFP) fusion is found diffused throughout the cell. Overexpression of spMex67p inhibits growth and mRNA export and results in the redistribution of the diffused localization of the (149–505)-GFP fusion to the nucleus and the nuclear periphery. These results suggest that spMex67p competes for essential mRNA export factor(s). Finally, we propose that the 149–505 region of spMex67p could act as an accessory factor in Rae1p-dependent transport and that spMex67p participates at various common steps with Rae1p export complexes in promoting the export of mRNA.

scholarly journals Structure Unveils Relationships between RNA Virus Polymerases

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 313
Author(s):  
Heli A. M. Mönttinen ◽  
Janne J. Ravantti ◽  
Minna M. Poranen
Keyword(s):  
Phylogenetic Tree ◽  
Rna Viruses ◽  
Rna Virus ◽  
Sequence Similarity ◽  
Protein Structures ◽  
Structural Similarity ◽  
Functional Differentiation ◽  
Comparison Method ◽  
Homologous Structure ◽  
Biological Entities

RNA viruses are the fastest evolving known biological entities. Consequently, the sequence similarity between homologous viral proteins disappears quickly, limiting the usability of traditional sequence-based phylogenetic methods in the reconstruction of relationships and evolutionary history among RNA viruses. Protein structures, however, typically evolve more slowly than sequences, and structural similarity can still be evident, when no sequence similarity can be detected. Here, we used an automated structural comparison method, homologous structure finder, for comprehensive comparisons of viral RNA-dependent RNA polymerases (RdRps). We identified a common structural core of 231 residues for all the structurally characterized viral RdRps, covering segmented and non-segmented negative-sense, positive-sense, and double-stranded RNA viruses infecting both prokaryotic and eukaryotic hosts. The grouping and branching of the viral RdRps in the structure-based phylogenetic tree follow their functional differentiation. The RdRps using protein primer, RNA primer, or self-priming mechanisms have evolved independently of each other, and the RdRps cluster into two large branches based on the used transcription mechanism. The structure-based distance tree presented here follows the recently established RdRp-based RNA virus classification at genus, subfamily, family, order, class and subphylum ranks. However, the topology of our phylogenetic tree suggests an alternative phylum level organization.

scholarly journals Paenibacillus xinjiangensis sp. nov., isolated from Xinjiang province in China

2006 ◽  
Vol 56 (11) ◽  
pp. 2579-2582 ◽  
Author(s):  
Jee-Min Lim ◽  
Che Ok Jeon ◽  
Dong-Jin Park ◽  
Li-Hua Xu ◽  
Cheng-Lin Jiang ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Sequence ◽  
Sequence Similarity ◽  
Diaminopimelic Acid ◽  
16S Rrna Gene Sequence ◽  
Rrna Gene ◽  
Rrna Gene Sequence ◽  
16S Rrna Gene Sequences ◽  
Sequence Similarities

Strain B538T is a Gram-positive, motile, rod-shaped bacterium, which was isolated from Xinjiang province in China. This organism grew optimally at 30–35 °C and pH 8.0–8.5. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain B538T belonged to the genus Paenibacillus and chemotaxonomic data (DNA G+C content, 47.0 mol%; major isoprenoid quinone, MK-7; cell wall type, A1γ meso-diaminopimelic acid; major fatty acids, anteiso-C15 : 0 and C16 : 0) supported affiliation of the isolate with the genus Paenibacillus. Comparative 16S rRNA gene sequence analyses showed that the isolate was most closely related to Paenibacillus glycanilyticus DS-1T, with 16S rRNA gene sequence similarity of 98.1 %; sequence similarities to other members of the genus Paenibacillus used in the phylogenetic tree were less than 96.5 %. The DNA–DNA relatedness between strain B538T and P. glycanilyticus DS-1T was about 8.0 %. On the basis of physiological and molecular properties, strain B538T (=KCTC 3952T=DSM 16970T) is proposed as the type strain of a novel species within the genus Paenibacillus, for which the name Paenibacillus xinjiangensis sp. nov. is proposed.

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