The triple gene block movement proteins of a grape virus in the genus Foveavirus confer limited cell-to-cell spread of a mutant Potato virus X

Virus Genes ◽  
2013 ◽  
Vol 47 (1) ◽  
pp. 93-104 ◽  
Author(s):  
Krinpreet Mann ◽  
Baozhong Meng
Keyword(s):  
Potato Virus ◽  
Triple Gene Block ◽  
Potato Virus X ◽  
Movement Proteins ◽  
Gene Block ◽  
Block Movement ◽  
Cell Spread

scholarly journals In Vivo Translation of the Triple Gene Block of Potato Virus X Requires Two Subgenomic mRNAs

1998 ◽  
Vol 72 (10) ◽  
pp. 8316-8320 ◽  
Author(s):  
Jeanmarie Verchot ◽  
Susan M. Angell ◽  
David C. Baulcombe
Keyword(s):  
Potato Virus ◽  
Triple Gene Block ◽  
Mrna Translation ◽  
Potato Virus X ◽  
Open Reading Frames ◽  
Movement Proteins ◽  
Gene Block ◽  
Overlapping Open Reading Frames ◽  
Reading Frames

ABSTRACT The 25-kilodalton (25K), 12K, and 8K movement proteins of potato virus X are derived from overlapping open reading frames (ORFs). Using an in vivo complementation assay, we have shown that the 25K protein is expressed from a functionally monocistronic mRNA, whereas the 12K and 8K proteins are from a bicistronic mRNA. Translation of the 8K ORF is by leaky ribosome scanning through the 12K ORF.

scholarly journals The Potato Virus X TGBp2 Protein Plays Dual Functional Roles in Viral Replication and Movement

2018 ◽  
Vol 93 (5) ◽  
Author(s):  
Xiaoyun Wu ◽  
Jiahui Liu ◽  
Mengzhu Chai ◽  
Jinhui Wang ◽  
Dalong Li ◽  
...  
Keyword(s):  
Triple Gene Block ◽  
Potato Virus X ◽  
Plant Viruses ◽  
Open Reading Frames ◽  
Movement Proteins ◽  
Gene Block ◽  
Functional Roles ◽  
Viral Rdrp ◽  
Dual Functional ◽  
Intercellular Movement

ABSTRACTPlant viruses usually encode one or more movement proteins (MP) to accomplish their intercellular movement. A group of positive-strand RNA plant viruses requires three viral proteins (TGBp1, TGBp2, and TGBp3) that are encoded by an evolutionarily conserved genetic module of three partially overlapping open reading frames (ORFs), termed the triple gene block (TGB). However, how these three viral movement proteins function cooperatively in viral intercellular movement is still elusive. Using a novelin vivodouble-stranded RNA (dsRNA) labeling system, we showed that the dsRNAs generated by potato virus X (PVX) RNA-dependent RNA polymerase (RdRp) are colocalized with viral RdRp, which are further tightly covered by “chain mail”-like TGBp2 aggregates and localizes alongside TGBp3 aggregates. We also discovered that TGBp2 interacts with the C-terminal domain of PVX RdRp, and this interaction is required for the localization of TGBp3 and itself to the RdRp/dsRNA bodies. Moreover, we reveal that the central and C-terminal hydrophilic domains of TGBp2 are required to interact with viral RdRp. Finally, we demonstrate that knockout of the entire TGBp2 or the domain involved in interacting with viral RdRp attenuates both PVX replication and movement. Collectively, these findings suggest that TGBp2 plays dual functional roles in PVX replication and intercellular movement.IMPORTANCEMany plant viruses contain three partially overlapping open reading frames (ORFs), termed the triple gene block (TGB), for intercellular movement. However, how the corresponding three proteins coordinate their functions remains obscure. In the present study, we provided multiple lines of evidence supporting the notion that PVX TGBp2 functions as the molecular adaptor bridging the interaction between the RdRp/dsRNA body and TGBp3 by forming “chain mail”-like structures in the RdRp/dsRNA body, which can also enhance viral replication. Taken together, our results provide new insights into the replication and movement of PVX and possibly also other TGB-containing plant viruses.

scholarly journals Expression Strategy of the Potato Virus X Triple Gene Block

1991 ◽  
Vol 72 (8) ◽  
pp. 2039-2042 ◽  
Author(s):  
S. Yu. Morozov ◽  
N. A. Miroshnichenko ◽  
A. G. Solovyev ◽  
O. N. Fedorkin ◽  
D. A. Zelenina ◽  
...  
Keyword(s):  
Potato Virus ◽  
Triple Gene Block ◽  
Potato Virus X ◽  
Gene Block

scholarly journals Cell-to-Cell Movement of Potato virus X: The Role of p12 and p8 Encoded by the Second and Third Open Reading Frames of the Triple Gene Block

2001 ◽  
Vol 14 (10) ◽  
pp. 1158-1167 ◽  
Author(s):  
Atsushi Tamai ◽  
Tetsuo Meshi
Keyword(s):  
Potato Virus ◽  
Fluorescent Protein ◽  
Microprojectile Bombardment ◽  
Triple Gene Block ◽  
Cell Movement ◽  
Potato Virus X ◽  
Open Reading Frames ◽  
Gene Block ◽  
Infected Cells ◽  
Green Fluorescent

Potato virus X (PVX) requires three proteins, p25, p12, and p8, encoded by the triple gene block plus the coat protein (CP) for cell-to-cell movement. When each of these proteins was co-expressed with a cytosolic green fluorescent protein (GFP) in the epidermal cells of Nicotiana benthamiana by the microprojectile bombardment-mediated gene delivery method, only p12 enhanced diffusion of co-expressed GFP, indicating an ability to alter plasmodesmal permeability. p25, p12, and CP, expressed transiently in the initially infected cells, transcomplemented the corresponding movement-defective mutants to spread through two or more cell boundaries. Thus, these proteins probably move from cell to cell with the genomic RNA. In contrast, p8 only functioned intracellularly and was not absolutely required for cell-to-cell movement. Since overexpression of p12 overcame the p8 deficiency, p8 appears to facilitate the functioning of p12, presumably by mediating its intracellular trafficking. Considering the likelihood that p12 and p8 are membrane proteins, it is suggested that intercellular as well as intracellular movement of PVX involves a membrane-mediated process.

scholarly journals Subcellular localization of the Triple Gene Block movement proteins of Beet necrotic yellow vein virus by electron microscopy

Virology ◽  
2005 ◽  
Vol 340 (1) ◽  
pp. 155-166 ◽  
Author(s):  
M. Erhardt ◽  
G. Vetter ◽  
D. Gilmer ◽  
S. Bouzoubaa ◽  
K. Richards ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Subcellular Localization ◽  
Triple Gene Block ◽  
Yellow Vein ◽  
Movement Proteins ◽  
Gene Block ◽  
Block Movement

scholarly journals Plant Translation Elongation Factor 1Bβ Facilitates Potato Virus X (PVX) Infection and Interacts with PVX Triple Gene Block Protein 1

PLoS ONE ◽  
2015 ◽  
Vol 10 (5) ◽  
pp. e0128014 ◽  
Author(s):  
JeeNa Hwang ◽  
Seonhee Lee ◽  
Joung-Ho Lee ◽  
Won-Hee Kang ◽  
Jin-Ho Kang ◽  
...  
Keyword(s):  
Potato Virus ◽  
Triple Gene Block ◽  
Elongation Factor ◽  
Potato Virus X ◽  
Translation Elongation Factor ◽  
Translation Elongation ◽  
Gene Block ◽  
Triple Gene Block Protein

scholarly journals Replication and trafficking of a plant virus are coupled at the entrances of plasmodesmata

2013 ◽  
Vol 201 (7) ◽  
pp. 981-995 ◽  
Author(s):  
Jens Tilsner ◽  
Olga Linnik ◽  
Marion Louveaux ◽  
Ian M. Roberts ◽  
Sean N. Chapman ◽  
...  
Keyword(s):  
Plant Virus ◽  
Plant Cell Wall ◽  
Triple Gene Block ◽  
Potato Virus X ◽  
Plant Viruses ◽  
Viral Coat Protein ◽  
Movement Proteins ◽  
Gene Block ◽  
Replication Sites ◽  
Viral Coat

Plant viruses use movement proteins (MPs) to modify intercellular pores called plasmodesmata (PD) to cross the plant cell wall. Many viruses encode a conserved set of three MPs, known as the triple gene block (TGB), typified by Potato virus X (PVX). In this paper, using live-cell imaging of viral RNA (vRNA) and virus-encoded proteins, we show that the TGB proteins have distinct functions during movement. TGB2 and TGB3 established endoplasmic reticulum–derived membranous caps at PD orifices. These caps harbored the PVX replicase and nonencapsidated vRNA and represented PD-anchored viral replication sites. TGB1 mediated insertion of the viral coat protein into PD, probably by its interaction with the 5′ end of nascent virions, and was recruited to PD by the TGB2/3 complex. We propose a new model of plant virus movement, which we term coreplicational insertion, in which MPs function to compartmentalize replication complexes at PD for localized RNA synthesis and directional trafficking of the virus between cells.

scholarly journals Evidence that the Linker between the Methyltransferase and Helicase Domains of Potato Virus X Replicase Is Involved in Homologous RNA Recombination

2009 ◽  
Vol 83 (15) ◽  
pp. 7761-7769 ◽  
Author(s):  
Heidrun-Katharina Draghici ◽  
Mark Varrelmann
Keyword(s):  
Coat Protein ◽  
Potato Virus ◽  
Fluorescent Protein ◽  
Triple Gene Block ◽  
Leaf Tissue ◽  
Potato Virus X ◽  
Wild Type Virus ◽  
Rna Recombination ◽  
Gene Block

ABSTRACT Recombination in RNA viruses, one of the main factors contributing to their genetic variability and evolution, is a widespread phenomenon. In this study, an in vivo assay to characterize RNA recombination in potato virus X (PVX), under high selection pressure, was established. Agrobacterium tumefaciens was used to express in Nicotiana benthamiana leaf tissue both a PVX isolate labeled with green fluorescent protein (GFP) containing a coat protein deletion mutation (ΔCP) and a transcript encoding a functional coat protein +3′-ntr. Coexpression of the constructs led to virus movement and systemic infection; reconstituted recombinants were observed in 92% of inoculated plants. Similar results were obtained using particle bombardment, demonstrating that recombination mediated by A. tumefaciens was not responsible for the occurrence of PXC recombinants. The speed of recombination could be estimated by agroinfection of two PVX mutants lacking the 3′ and 5′ halves of the genome, respectively, with an overlap in the triple gene block 1 gene, allowing GFP expression only in the case of recombination. Ten different pentapeptide insertion scanning replicase mutants with replication abilities comparable to wild-type virus were applied in the different recombination assays. Two neighboring mutants affecting the linker between the methyltransferase and helicase domains were shown to be strongly debilitated in their ability to recombine. The possible functional separation of replication and recombination in the replicase molecule supports the model that RNA recombination represents a distinct function of this protein, although the underlying mechanism still needs to be investigated.

scholarly journals Microscopic Analysis of Severe Structural Rearrangements of the Plant Endoplasmic Reticulum and Golgi Caused by Overexpression ofPoa semilatent virusMovement Protein

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Andrey G. Solovyev ◽  
Joachim Schiemann ◽  
Sergey Y. Morozov
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Triple Gene Block ◽  
Microscopic Analysis ◽  
Potato Virus X ◽  
Plant Viruses ◽  
Genomic Rnas ◽  
Movement Proteins ◽  
Gene Block ◽  
Ribonucleoprotein Complexes

Cell-to-cell transport of plant viruses is mediated by virus-encoded movement proteins and occurs through plasmodesmata interconnecting neighboring cells in plant tissues. Three movement proteins coded by the “triple gene block” (TGB) and named TGBp1, TGBp2 and TGBp3 have distinct functions in viral transport. TGBp1 binds viral genomic RNAs to form ribonucleoprotein complexes representing the transport form of viral genome, while TGBp2 and TGBp3 are necessary for intracellular delivery of such complexes to plasmodesmata. Recently, it was revealed that overexpression ofPotato virus XTGBp3 triggers the unfolded protein response mitigating the endoplasmic reticulum (ER) stress leading to cell death if this protein reaches high levels in the ER. Here we report microscopic studies of the influence of thePoa semilatent hordeivirusTGBp3 overexpressed inNicotiana benthamianaepidermal cells by particle bombardment on cell endomembranes and demonstrate that the protein C-terminal transmembrane segment contains a determinant responsible for vesiculation and coalescence of the endoplasmic reticulum and Golgi presumably accompanying the ER stress that can be induced upon high-level TGBp3 expression.

scholarly journals Tritium planigraphy study of structural alterations in the coat protein of Potato virus X induced by binding of its triple gene block 1 protein to virions

FEBS Journal ◽  
2009 ◽  
Vol 276 (23) ◽  
pp. 7006-7015 ◽  
Author(s):  
Elena Lukashina ◽  
Gennady Badun ◽  
Natalia Fedorova ◽  
Alexander Ksenofontov ◽  
Maria Nemykh ◽  
...  
Keyword(s):  
Coat Protein ◽  
Potato Virus ◽  
Triple Gene Block ◽  
Potato Virus X ◽  
Structural Alterations ◽  
Tritium Planigraphy ◽  
Gene Block
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