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Yauheiu Hsu - One of the best experts on this subject based on the ideXlab platform.

  • proliferating cell nuclear antigen suppresses rna replication of bamboo mosaic virus through an interaction with the viral genome
    Journal of Virology, 2019
    Co-Authors: Chengcheng Lee, Yauheiu Hsu, Ying-wen Huang, Jhihwei Wang, Weiming Leu, Yuting Huang, Menghsiao Meng
    Abstract:

    Bamboo mosaic virus (BaMV), a member of the Potexvirus genus, has a monopartite positive-strand RNA genome on which five open reading frames (ORFs) are organized. ORF1 encodes a 155-kDa nonstructural protein (REPBaMV) that plays a core function in replication/transcription of the viral genome. To find out cellular factors modulating the replication efficiency of BaMV, a putative REPBaMV-associated protein complex from Nicotiana benthamiana leaf was isolated on an SDS-PAGE gel, and a few proteins preferentially associated with REPBaMV were identified by tandem mass spectrometry. Among them, proliferating cell nuclear antigen (PCNA) was particularly noted. Overexpression of PCNA strongly suppressed the accumulation of BaMV coat protein and RNAs in leaf protoplasts. In addition, PCNA exhibited an inhibitory effect on BaMV polymerase activity. A pulldown assay confirmed a binding capability of PCNA toward BaMV genomic RNA. Mutations at D41 or F114 residues, which are critical for PCNA to function in nuclear DNA replication and repair, disabled PCNA from binding BaMV genomic RNA as well as suppressing BaMV replication. This suggests that PCNA bound to the viral RNA may interfere with the formation of a potent replication complex or block the replication process. Interestingly, BaMV is almost invisible in the newly emerging leaves where PCNA is actively expressed. Accordingly, PCNA is probably one of the factors restricting the proliferation of BaMV in young leaves. Foxtail mosaic virus and Potato virus X were also suppressed by PCNA in the protoplast experiment, suggesting a general inhibitory effect of PCNA on the replication of Potexviruses.IMPORTANCE Knowing the dynamic interplay between plant RNA viruses and their host is a basic step toward first understanding how the viruses survive the plant defense mechanisms and second gaining knowledge of pathogenic control in the field. This study found that plant proliferating cell nuclear antigen (PCNA) imposes a strong inhibition on the replication of several Potexviruses, including Bamboo mosaic virus, Foxtail mosaic virus, and Potato virus X Based on the tests on Bamboo mosaic virus, PCNA is able to bind the viral genomic RNA, and this binding is a prerequisite for the protein to suppress the virus replication. This study also suggests that PCNA plays an important role in restricting the proliferation of Potexviruses in the rapidly dividing tissues of plants.

  • viral elements and host cellular proteins in intercellular movement of bamboo mosaic virus
    Current Opinion in Virology, 2015
    Co-Authors: Mingru Liou, Yuanlin Chou, Na-sheng Lin, Banyang Chang, Yauheiu Hsu
    Abstract:

    As a member of the genus Potexvirus, Bamboo mosaic virus (BaMV) also belongs to the plant viruses that encode triple gene block proteins (TGBps) for intercellular movement within the host plants. Recent studies of the movement mechanisms of BaMV have revealed similarities and differences between BaMV and other Potexviruses. This review focuses on the general aspects of viral and host elements involved in BaMV movement, the interactions among these elements, and the possible pathways for intra- and intercellular trafficking of BaMV. Major features of BaMV trafficking that have not been demonstrated in other Potexviruses include: (i) the involvement of replicase, (ii) fine regulation by coat protein phosphorylation, (iii) the key roles played by TGBp3, (iv) the use of virions as the major transported form, and (v) the involvement of specific host factors, such as Ser/Thr kinase-like protein of Nicotiana benthamiana. We also highlight areas for future study that will provide a more comprehensive understanding of the detailed interactions among viral movement proteins and host factors, as well as the regulatory mechanisms of virus movement. Finally, a model based on the current knowledge is proposed to depict the diverse abilities of BaMV to utilize a wide range of mechanisms for efficient intercellular movement.

  • the two conserved cysteine residues of the triple gene block protein 2 are critical for both cell to cell and systemic movement of bamboo mosaic virus
    Molecular Plant-microbe Interactions, 2009
    Co-Authors: Yanghao Tseng, Yauheiu Hsu, Na-sheng Lin, Hsiuting Hsu, Yuanlin Chou, Banyang Chang
    Abstract:

    The triple gene block protein 2 (TGBp2) of Bamboo mosaic virus (BaMV) is a transmembrane protein which is known to be required for the cell-to-cell movement of Potexviruses. This protein has two conserved Cys residues, Cys-109 and Cys-112, at its C-terminal tail, which is supposed to be exposed on the outer surface of the endoplasmic reticulum (ER) membrane and ER-derived granular vesicles. In this study, we investigated the importance of these two Cys residues on the cell-to-cell and systemic movement of BaMV. Our results indicate that the Cys-to-Ala substitutions in TGBp2 make the cell-to-cell movement of BaMV relatively inefficient and the systemic movement of BaMV severely inhibited. Moreover, the defect in systemic movement is attributed to the inefficient transport of viral RNA in the phloem of petiole. Clearly, TGBp2 is critical not only for the cell-to-cell but also for the systemic movement of BaMV. In addition, the conserved Cys residues are important for the functioning of TGBp2.

  • movement of Potexviruses requires species specific interactions among the cognate triple gene block proteins as revealed by a trans complementation assay based on the bamboo mosaic virus satellite rna mediated expression system
    Journal of General Virology, 2006
    Co-Authors: Mingkuem Lin, Banyang Chang, Na-sheng Lin, Yauheiu Hsu
    Abstract:

    The intra- and intercellular transport of Potexviruses require interactions among viral RNA, coat protein and elements of the triple gene block proteins (TGBps). In this study, the requirement of bamboo mosaic virus (BaMV) TGBps for movement functions and the compatibilities with those of two Potexviruses, Potato virus X (PVX) and Foxtail mosaic virus (FoMV), were examined using a satellite RNA-mediated trans-complementation assay system. Single or multiple TGBps of BaMV, PVX and FoMV were expressed from BaMV satellite RNA (satBaMV RNA) vectors to complement the functions of green fluorescent protein-tagged, movement-defective BaMV with mutation(s) in the matching gene(s). It was found that individual BaMV TGBps expressed from the satellite vector could function normally in trans, whereas bi-gene BaMV TGBp constructs in which the expression of TGBp3 might be impaired and individual TGBp genes from PVX or FoMV could not complement the movement functions of the defective helper viruses. Furthermore, alterations of the ratio among TGBps by ectopic expression of individual components of TGBps from satBaMV RNA vectors did not affect the cell-to-cell movement capabilities of wild-type BaMV significantly. The results indicate that species-specific interactions among movement proteins are obligatory for the cell-to-cell movement of BaMV and possibly other Potexviruses.

  • The data warehousing, CWM and MOF resource page. http://www. omg.org/cwm
    2002
    Co-Authors: Mingkuem Lin, Banyang Chang, Na-sheng Lin, Yauheiu Hsu
    Abstract:

    Potexviruses requires speciesspecific interactions among the cognate triple gene block proteins, as revealed by a transcomplementation assay based on the bamboo mosaic virus satellite RNA-mediated expression syste

Na-sheng Lin - One of the best experts on this subject based on the ideXlab platform.

  • viral elements and host cellular proteins in intercellular movement of bamboo mosaic virus
    Current Opinion in Virology, 2015
    Co-Authors: Mingru Liou, Yuanlin Chou, Na-sheng Lin, Banyang Chang, Yauheiu Hsu
    Abstract:

    As a member of the genus Potexvirus, Bamboo mosaic virus (BaMV) also belongs to the plant viruses that encode triple gene block proteins (TGBps) for intercellular movement within the host plants. Recent studies of the movement mechanisms of BaMV have revealed similarities and differences between BaMV and other Potexviruses. This review focuses on the general aspects of viral and host elements involved in BaMV movement, the interactions among these elements, and the possible pathways for intra- and intercellular trafficking of BaMV. Major features of BaMV trafficking that have not been demonstrated in other Potexviruses include: (i) the involvement of replicase, (ii) fine regulation by coat protein phosphorylation, (iii) the key roles played by TGBp3, (iv) the use of virions as the major transported form, and (v) the involvement of specific host factors, such as Ser/Thr kinase-like protein of Nicotiana benthamiana. We also highlight areas for future study that will provide a more comprehensive understanding of the detailed interactions among viral movement proteins and host factors, as well as the regulatory mechanisms of virus movement. Finally, a model based on the current knowledge is proposed to depict the diverse abilities of BaMV to utilize a wide range of mechanisms for efficient intercellular movement.

  • a unique glycine rich motif at the n terminal region of bamboo mosaic virus coat protein is required for symptom expression
    Molecular Plant-microbe Interactions, 2010
    Co-Authors: Ping Lan, Wen-bin Yeh, Chihwei Tsai, Na-sheng Lin
    Abstract:

    The coat proteins (CP) of many plant viruses are multifunctional proteins. We used N-terminal sequencing and mass spectrometry/mass spectrometry analysis to identify a truncated form of the Bamboo mosaic virus (BaMV) CP missing the N-terminal 35 amino acids (N35). The N35 region is unique in the Potexviruses by its containing a glycine-rich motif (GRM) not present in databases but highly conserved among BaMV isolates. Results from site-directed mutagenesis and deletion mutational analysis showed that loss of this region converted necrotic local lesions to chlorotic local lesions on Chenopodium quinoa leaves. Furthermore, this region is required for successful development of mosaic symptoms on Nicotiana benthamiana leaves but is dispensable for BaMV replication and cell-to-cell and long-distance movement as well as virion assembly. This unique GRM-containing region of BaMV CP may be a symptom determinant in specific hosts.

  • the two conserved cysteine residues of the triple gene block protein 2 are critical for both cell to cell and systemic movement of bamboo mosaic virus
    Molecular Plant-microbe Interactions, 2009
    Co-Authors: Yanghao Tseng, Yauheiu Hsu, Na-sheng Lin, Hsiuting Hsu, Yuanlin Chou, Banyang Chang
    Abstract:

    The triple gene block protein 2 (TGBp2) of Bamboo mosaic virus (BaMV) is a transmembrane protein which is known to be required for the cell-to-cell movement of Potexviruses. This protein has two conserved Cys residues, Cys-109 and Cys-112, at its C-terminal tail, which is supposed to be exposed on the outer surface of the endoplasmic reticulum (ER) membrane and ER-derived granular vesicles. In this study, we investigated the importance of these two Cys residues on the cell-to-cell and systemic movement of BaMV. Our results indicate that the Cys-to-Ala substitutions in TGBp2 make the cell-to-cell movement of BaMV relatively inefficient and the systemic movement of BaMV severely inhibited. Moreover, the defect in systemic movement is attributed to the inefficient transport of viral RNA in the phloem of petiole. Clearly, TGBp2 is critical not only for the cell-to-cell but also for the systemic movement of BaMV. In addition, the conserved Cys residues are important for the functioning of TGBp2.

  • movement of Potexviruses requires species specific interactions among the cognate triple gene block proteins as revealed by a trans complementation assay based on the bamboo mosaic virus satellite rna mediated expression system
    Journal of General Virology, 2006
    Co-Authors: Mingkuem Lin, Banyang Chang, Na-sheng Lin, Yauheiu Hsu
    Abstract:

    The intra- and intercellular transport of Potexviruses require interactions among viral RNA, coat protein and elements of the triple gene block proteins (TGBps). In this study, the requirement of bamboo mosaic virus (BaMV) TGBps for movement functions and the compatibilities with those of two Potexviruses, Potato virus X (PVX) and Foxtail mosaic virus (FoMV), were examined using a satellite RNA-mediated trans-complementation assay system. Single or multiple TGBps of BaMV, PVX and FoMV were expressed from BaMV satellite RNA (satBaMV RNA) vectors to complement the functions of green fluorescent protein-tagged, movement-defective BaMV with mutation(s) in the matching gene(s). It was found that individual BaMV TGBps expressed from the satellite vector could function normally in trans, whereas bi-gene BaMV TGBp constructs in which the expression of TGBp3 might be impaired and individual TGBp genes from PVX or FoMV could not complement the movement functions of the defective helper viruses. Furthermore, alterations of the ratio among TGBps by ectopic expression of individual components of TGBps from satBaMV RNA vectors did not affect the cell-to-cell movement capabilities of wild-type BaMV significantly. The results indicate that species-specific interactions among movement proteins are obligatory for the cell-to-cell movement of BaMV and possibly other Potexviruses.

  • The data warehousing, CWM and MOF resource page. http://www. omg.org/cwm
    2002
    Co-Authors: Mingkuem Lin, Banyang Chang, Na-sheng Lin, Yauheiu Hsu
    Abstract:

    Potexviruses requires speciesspecific interactions among the cognate triple gene block proteins, as revealed by a transcomplementation assay based on the bamboo mosaic virus satellite RNA-mediated expression syste

Shigetou Namba - One of the best experts on this subject based on the ideXlab platform.

  • a replicase of potato virus x acts as the resistance breaking determinant for jax1 mediated resistance
    Molecular Plant-microbe Interactions, 2013
    Co-Authors: Kyoko Sugawara, Yasuyuki Yamaji, Takuya Shiraishi, Tetsuya Yoshida, Osamu Netsu, Naoko Fujita, Shigetou Namba
    Abstract:

    Lectin-mediated resistance (LMR) has been suggested to comprise an uncharacterized branch of antiviral plant innate immunity. To unveil the feature of resistance conferred by jacalin-type lectin required for potexvirus resistance 1 (JAX1), a recently isolated LMR gene against Potexviruses, we analyzed the resistance-breaking variants to find the viral component involved in resistance. We employed grafting-mediated inoculation, a high-pressure virus inoculation method, to obtain Potato virus X (PVX) variants that can overcome JAX1-mediated resistance. Whole-genome sequencing of the variants suggested that a single amino acid in the methyl transferase domain of the replicase encoded by PVX is responsible for this resistance-breaking property. Reintroduction of the amino-acid substitution to avirulent wild-type PVX was sufficient to overcome the JAX1-mediated resistance. These results suggest that viral replicase is involved in JAX1-mediated resistance. The residue that determines the resistance-breaking pro...

  • variability in the level of rna silencing suppression caused by triple gene block protein 1 tgbp1 from various Potexviruses during infection
    Journal of General Virology, 2009
    Co-Authors: Hiroko Senshu, Yasuyuki Yamaji, Ken Komatsu, Johji Ozeki, Masayoshi Hashimoto, Satoshi Kagiwada, Kouji Hatada, Michiko Aoyama, Shigetou Namba
    Abstract:

    RNA silencing is an important defence mechanism against virus infection, and many plant viruses encode RNA silencing suppressors as a counter defence. In this study, we analysed the RNA silencing suppression ability of multiple virus species of the genus Potexvirus. Nicotiana benthamiana plants exhibiting RNA silencing of a green fluorescent protein (GFP) transgene showed reversal of GFP fluorescence when systemically infected with Potexviruses. However, the degree of GFP fluorescence varied among Potexviruses. Agrobacterium-mediated transient expression assay in N. benthamiana leaves demonstrated that the triple gene block protein 1 (TGBp1) encoded by these Potexviruses has drastically different levels of silencing suppressor activity, and these differences were directly related to variations in the silencing suppression ability during virus infection. These results suggest that suppressor activities differ even among homologous proteins encoded by viruses of the same genus, and that TGBp1 contributes to the variation in the level of RNA silencing suppression by Potexviruses. Moreover, we investigated the effect of TGBp1 encoded by Plantago asiatica mosaic virus (PlAMV), which exhibited a strong suppressor activity, on the accumulation of microRNA, virus genomic RNA and virus-derived small interfering RNAs.

  • nucleotide sequence analysis of seven japanese isolates of plantago asiatica mosaic virus plamv a unique potexvirus with significantly high genomic and biological variability within the species
    Archives of Virology, 2008
    Co-Authors: Ken Komatsu, Yasuyuki Yamaji, Johji Ozeki, Masayoshi Hashimoto, Satoshi Kagiwada, Shuichiro Takahashi, Shigetou Namba
    Abstract:

    The genomic sequences of Plantago asiatica mosaic virus (PlAMV), six lily isolates and one primrose isolate from Japan, were determined. The genomic size of all isolates was 6102 nucleotides, containing the five open reading frames typical of members of the genus Potexvirus. Pairwise comparison analyses confirmed the close relationship between PlAMV and tulip virus X. However, quite low identities were observed between different PlAMV isolates, including foreign isolates; nucleotide sequence identities of the RNA-dependent RNA polymerase (RdRp) gene between a Russian isolate (PlAMV-Ru), a Nandina isolate (PlAMV-Na) and Japanese isolates were 75–77%. These values were the lowest amongst different isolates of the same species of any Potexviruses.

  • complete nucleotide sequence of tulip virus x tvx j the border between species and strains within the genus potexvirus
    Archives of Virology, 2001
    Co-Authors: Yasuyuki Yamaji, Satoshi Kagiwada, Hitomi Nakabayashi, Masashi Ugaki, Shigetou Namba
    Abstract:

    The complete nucleotide sequence of the genomic RNA of Tulip virus X Japanese isolate (TVX-J) has been determined. The sequence is 6056 nucleotides in length, excluding the poly(A) tail at the 3′ terminus, and contains five open reading frames (ORFs) coding for proteins of M r 153, 25, 12, 10, and 22 kDa (ORFs 1 through 5, respectively). The genome organization of TVX-J is similar to that of Potexviruses, and the encoded proteins share a high degree of homology to the corresponding proteins of other Potexviruses. Phylogenetic analyses based on the RNA-dependent RNA polymerase (RdRp) protein (the methyltransferase, helicase, and polymerase domains) encoded by ORF1 and the capsid protein (CP) encoded by ORF5, revealed a close relationship of TVX-J to Plantago asiatica mosaic virus (PlAMV). Pairwise comparison analyses revealed that the relationship between TVX and PlAMV is intermediate between that of strains and species, though previously they have not been considered related. Due to the relatively distant relationships of their replication apparatus and triple gene blocks, we conclude that TVX and PlAMV should be classified as distinct viruses. In addition, the borderline between species and strains of Potexviruses is discussed.

George A. Mackie - One of the best experts on this subject based on the ideXlab platform.

  • Journal of General Virology (199l), 72, 2173-2181. Printed in Great Britain 2173 The entire nucleotide sequence of foxtail mosaic virus RNA
    2013
    Co-Authors: J.b. Bancroft, R. Johnston, L. Prins, George A. Mackie
    Abstract:

    The nucleotide sequence of the RNA genome of foxtail mosaic virus (FMV), a member of the potexvirus family, is 6151 nucleotides long, exclusive of a poly(A) tail. The RNA contains five principal open reading frames (ORFs), designated from the 5 ' terminus as encoding proteins with Mr values of 152.3K (ORF1), 26.4K (ORF2) which overlaps an I1-3K (ORF3) product, 5.8K (ORF4) which overlaps a 28-8K readthrough protein (ORF5A) which leads into the coat protein cistron of 23-7K (ORF5). The sizes and composition of the proteins encoded by the ORFs are generally similar to those found in other Potexviruses

  • Subcellular Immunolocalization of the Coat Protein of Two Potexviruses in InfectedChenopodium quinoa
    Virology, 1995
    Co-Authors: Michèle Rouleau, R.j. Smith, J.b. Bancroft, George A. Mackie
    Abstract:

    The production of coat protein is necessary for cell-to-cell transport of Potexviruses in plants. To investigate the role of coat protein in the movement process, the intracellular distribution of coat protein in tissues infected with either of two Potexviruses was studied using immunocytochemical procedures. We report that coat protein antigens are associated with the plasmodesmata of infected cells.

  • the entire nucleotide sequence of foxtail mosaic virus rna
    Journal of General Virology, 1991
    Co-Authors: J.b. Bancroft, Michèle Rouleau, R. Johnston, L. Prins, George A. Mackie
    Abstract:

    The nucleotide sequence of the RNA genome of foxtail mosaic virus (FMV), a member of the potexvirus family, is 6151 nucleotides long, exclusive of a poly(A) tail. The RNA contains five principal open reading frames (ORFs), designated from the 5′ terminus as encoding proteins with M r values of 152.3K (ORF1), 26.4K (ORF2) which overlaps an 11.3K (ORF3) product, 5.8K (ORF4) which overlaps a 28.8K readthrough protein (ORF5A) which leads into the coat protein cistron of 23.7K (ORF5). The sizes and composition of the proteins encoded by the ORFs are generally similar to those found in other Potexviruses; the least similar is the coat protein which nonetheless retains apparently critical consensus regions. The 5′ terminus of the previously reported 0.9 kb subgenomic (sg) RNA was determined by S1 nuclease mapping and shown to begin with the sequence GAAGA, 43 nucleotides upsteam from the first nucleotide of the coat protein initiation codon. The positions of the 5′ end of this sgRNA and of that deduced from the nucleotide sequence for a 1.9 kb sgRNA are entirely consistent with the previously published sizes of these sgRNAs.

Menghsiao Meng - One of the best experts on this subject based on the ideXlab platform.

  • proliferating cell nuclear antigen suppresses rna replication of bamboo mosaic virus through an interaction with the viral genome
    Journal of Virology, 2019
    Co-Authors: Chengcheng Lee, Yauheiu Hsu, Ying-wen Huang, Jhihwei Wang, Weiming Leu, Yuting Huang, Menghsiao Meng
    Abstract:

    Bamboo mosaic virus (BaMV), a member of the Potexvirus genus, has a monopartite positive-strand RNA genome on which five open reading frames (ORFs) are organized. ORF1 encodes a 155-kDa nonstructural protein (REPBaMV) that plays a core function in replication/transcription of the viral genome. To find out cellular factors modulating the replication efficiency of BaMV, a putative REPBaMV-associated protein complex from Nicotiana benthamiana leaf was isolated on an SDS-PAGE gel, and a few proteins preferentially associated with REPBaMV were identified by tandem mass spectrometry. Among them, proliferating cell nuclear antigen (PCNA) was particularly noted. Overexpression of PCNA strongly suppressed the accumulation of BaMV coat protein and RNAs in leaf protoplasts. In addition, PCNA exhibited an inhibitory effect on BaMV polymerase activity. A pulldown assay confirmed a binding capability of PCNA toward BaMV genomic RNA. Mutations at D41 or F114 residues, which are critical for PCNA to function in nuclear DNA replication and repair, disabled PCNA from binding BaMV genomic RNA as well as suppressing BaMV replication. This suggests that PCNA bound to the viral RNA may interfere with the formation of a potent replication complex or block the replication process. Interestingly, BaMV is almost invisible in the newly emerging leaves where PCNA is actively expressed. Accordingly, PCNA is probably one of the factors restricting the proliferation of BaMV in young leaves. Foxtail mosaic virus and Potato virus X were also suppressed by PCNA in the protoplast experiment, suggesting a general inhibitory effect of PCNA on the replication of Potexviruses.IMPORTANCE Knowing the dynamic interplay between plant RNA viruses and their host is a basic step toward first understanding how the viruses survive the plant defense mechanisms and second gaining knowledge of pathogenic control in the field. This study found that plant proliferating cell nuclear antigen (PCNA) imposes a strong inhibition on the replication of several Potexviruses, including Bamboo mosaic virus, Foxtail mosaic virus, and Potato virus X Based on the tests on Bamboo mosaic virus, PCNA is able to bind the viral genomic RNA, and this binding is a prerequisite for the protein to suppress the virus replication. This study also suggests that PCNA plays an important role in restricting the proliferation of Potexviruses in the rapidly dividing tissues of plants.

  • the helicase like domain of plant potexvirus replicase participates in formation of rna 5 cap structure by exhibiting rna 5 triphosphatase activity
    Journal of Virology, 2001
    Co-Authors: Tingwan Shih, Yauheiu Hsu, Yih-leh Huang, Yu-tsung Han, Menghsiao Meng
    Abstract:

    Open reading frame 1 (ORF1) of Potexviruses encodes a viral replicase comprising three functional domains: a capping enzyme at the N terminus, a putative helicase in the middle, and a polymerase at the C terminus. To verify the enzymatic activities associated with the putative helicase domain, the corresponding cDNA fragment from bamboo mosaic virus (BaMV) was cloned into vector pET32 and the protein was expressed in Escherichia coli and purified by metal affinity chromatography. An activity assay confirmed that the putative helicase domain has nucleoside triphosphatase activity. We found that it also possesses an RNA 5-triphosphatase activity that specifically removes the phosphate from the 5 end of RNA. Both enzymatic activities were abolished by the mutation of the nucleoside triphosphate-binding motif (GKS), suggesting that they have a common catalytic site. A typical m 7 GpppG cap structure was formed at the 5 end of the RNA