The Experts below are selected from a list of 108 Experts worldwide ranked by ideXlab platform

Judit Pogany - One of the best experts on this subject based on the ideXlab platform.

  • interviral recombination between plant insect and fungal rna Viruses role of the intracellular ca 2 mn 2 pump
    Journal of Virology, 2019
    Co-Authors: Nikolay Kovalev, Judit Pogany
    Abstract:

    Recombination is one of the driving forces of viral evolution. RNA recombination events among similar RNA Viruses are frequent, although RNA recombination could also take place among unrelated Viruses. In this paper, we have established efficient interviral recombination systems based on yeast and plants. We show that diverse RNA Viruses, including the plant Viruses tomato bushy stunt Virus, carnation Italian ringspot Virus, and turnip crinkle Virus-associated RNA; the insect plus-strand RNA [(+)RNA] Viruses Flock House Virus and Nodamura Virus; and the double-stranded L-A Virus of yeast, are involved in interviral recombination events. Most interviral recombinants are minus-strand recombinant RNAs, and the junction sites are not randomly distributed, but there are certain hot spot regions. Formation of interviral recombinants in yeast and plants is accelerated by depletion of the cellular SERCA-like Pmr1 ATPase-driven Ca(2+)/Mn(2+) pump, regulating intracellular Ca(2+) and Mn(2+) influx into the Golgi apparatus from the cytosol. The interviral recombinants are generated by a template-switching mechanism during RNA replication by the viral replicase. Replication studies revealed that a group of interviral recombinants is replication competent in cell-free extracts, in yeast, and in the plant Nicotiana benthamiana We propose that there are major differences among the viral replicases to generate and maintain interviral recombinants. Altogether, the obtained data promote the model that host factors greatly contribute to the formation of recombinants among related and unrelated Viruses. This is the first time that a host factor's role in affecting interviral recombination is established.IMPORTANCE Viruses with RNA genomes are abundant, and their genomic sequences show astonishing variation. Genetic recombination in RNA Viruses is a major force behind their rapid evolution, enhanced pathogenesis, and adaptation to their hosts. We utilized a previously identified intracellular Ca(2+)/Mn(2+) pump-deficient yeast to search for interviral recombinants. Noninfectious viral replication systems were used to avoid generating unwanted infectious interviral recombinants. Altogether, interviral RNA recombinants were observed between plant and insect Viruses, and between a fungal double-stranded RNA (dsRNA) Virus and an insect Virus, in the yeast host. In addition, interviral recombinants between two plant Virus replicon RNAs were identified in N. benthamiana plants, in which the intracellular Ca(2+)/Mn(2+) pump was depleted. These findings underline the crucial role of the host in promoting RNA recombination among unrelated Viruses.

  • interviral recombination between plant insect and fungal rna Viruses role of the intracellular ca2 mn2 pump
    Journal of Virology, 2019
    Co-Authors: Nikolay Kovalev, Judit Pogany
    Abstract:

    Recombination is one of the driving forces of viral evolution. RNA recombination events among similar RNA Viruses are frequent, although RNA recombination could also take place among unrelated Viruses. In this paper, we have established efficient interviral recombination systems based on yeast and plants. We show that diverse RNA Viruses, including the plant Viruses tomato bushy stunt Virus, carnation Italian ringspot Virus, and turnip crinkle Virus-associated RNA; the insect plus-strand RNA [(+)RNA] Viruses Flock House Virus and Nodamura Virus; and the double-stranded L-A Virus of yeast, are involved in interviral recombination events. Most interviral recombinants are minus-strand recombinant RNAs, and the junction sites are not randomly distributed, but there are certain hot spot regions. Formation of interviral recombinants in yeast and plants is accelerated by depletion of the cellular SERCA-like Pmr1 ATPase-driven Ca2+/Mn2+ pump, regulating intracellular Ca2+ and Mn2+ influx into the Golgi apparatus from the cytosol. The interviral recombinants are generated by a template-switching mechanism during RNA replication by the viral replicase. Replication studies revealed that a group of interviral recombinants is replication competent in cell-free extracts, in yeast, and in the plant Nicotiana benthamiana We propose that there are major differences among the viral replicases to generate and maintain interviral recombinants. Altogether, the obtained data promote the model that host factors greatly contribute to the formation of recombinants among related and unrelated Viruses. This is the first time that a host factor's role in affecting interviral recombination is established.IMPORTANCE Viruses with RNA genomes are abundant, and their genomic sequences show astonishing variation. Genetic recombination in RNA Viruses is a major force behind their rapid evolution, enhanced pathogenesis, and adaptation to their hosts. We utilized a previously identified intracellular Ca2+/Mn2+ pump-deficient yeast to search for interviral recombinants. Noninfectious viral replication systems were used to avoid generating unwanted infectious interviral recombinants. Altogether, interviral RNA recombinants were observed between plant and insect Viruses, and between a fungal double-stranded RNA (dsRNA) Virus and an insect Virus, in the yeast host. In addition, interviral recombinants between two plant Virus replicon RNAs were identified in N. benthamiana plants, in which the intracellular Ca2+/Mn2+ pump was depleted. These findings underline the crucial role of the host in promoting RNA recombination among unrelated Viruses.

  • The TPR Domain in the Host Cyp40-like Cyclophilin Binds to the Viral Replication Protein and Inhibits the Assembly of the Tombusviral Replicase
    PLoS pathogens, 2012
    Co-Authors: Jing-yi Lin, Judit Pogany, Venugopal Mendu, Jun Qin, Peter D. Nagy
    Abstract:

    Replication of plus-stranded RNA Viruses is greatly affected by numerous host-coded proteins acting either as susceptibility or resistance factors. Previous genome-wide screens and global proteomics approaches with Tomato bushy stunt tombusVirus (TBSV) in a yeast model host revealed the involvement of cyclophilins, which are a large family of host prolyl isomerases, in TBSV replication. In this paper, we identified those members of the large cyclophilin family that interacted with the viral replication proteins and inhibited TBSV replication. Further characterization of the most effective cyclophilin, the Cyp40-like Cpr7p, revealed that it strongly inhibits many steps during TBSV replication in a cell-free replication assay. These steps include viral RNA recruitment inhibited via binding of Cpr7p to the RNA-binding region of the viral replication protein; the assembly of the viral replicase complex and viral RNA synthesis. Since the TPR (tetratricopeptide repeats) domain, but not the catalytic domain of Cpr7p is needed for the inhibitory effect on TBSV replication, it seems that the chaperone activity of Cpr7p provides the negative regulatory function. We also show that three Cyp40-like proteins from plants can inhibit TBSV replication in vitro and Cpr7p is also effective against Nodamura Virus, an insect pathogen. Overall, the current work revealed a role for Cyp40-like proteins and their TPR domains as regulators of RNA Virus replication.

  • The TPR Domain in the Host Cyp40-like Cyclophilin Binds to the Viral Replication Protein and Inhibits the Assembly of the Tombusviral Replicase
    2011
    Co-Authors: Jing-yi Lin, Judit Pogany, Venugopal Mendu, Jun Qin, Peter D. Nagy
    Abstract:

    Replication of plus-stranded RNA Viruses is greatly affected by numerous host-coded proteins acting either as susceptibility or resistance factors. Previous genome-wide screens and global proteomics approaches with Tomato bushy stunt tombusVirus (TBSV) in a yeast model host revealed the involvement of cyclophilins, which are a large family of host prolyl isomerases, in TBSV replication. In this paper, we identified those members of the large cyclophilin family that interacted with the viral replication proteins and inhibited TBSV replication. Further characterization of the most effective cyclophilin, the Cyp40-like Cpr7p, revealed that it strongly inhibits many steps during TBSV replication in a cell-free replication assay. These steps include viral RNA recruitment inhibited via binding of Cpr7p to the RNA-binding region of the viral replication protein; the assembly of the viral replicase complex and viral RNA synthesis. Since the TPR (tetratricopeptide repeats) domain, but not the catalytic domain of Cpr7p is needed for the inhibitory effect on TBSV replication, it seems that the chaperone activity of Cpr7p provides the negative regulatory function. We also show that three Cyp40-like proteins from plants can inhibit TBSV replication in vitro and Cpr7p is also effective against Nodamura Virus, an insect pathogen. Overall

Nikolay Kovalev - One of the best experts on this subject based on the ideXlab platform.

  • interviral recombination between plant insect and fungal rna Viruses role of the intracellular ca 2 mn 2 pump
    Journal of Virology, 2019
    Co-Authors: Nikolay Kovalev, Judit Pogany
    Abstract:

    Recombination is one of the driving forces of viral evolution. RNA recombination events among similar RNA Viruses are frequent, although RNA recombination could also take place among unrelated Viruses. In this paper, we have established efficient interviral recombination systems based on yeast and plants. We show that diverse RNA Viruses, including the plant Viruses tomato bushy stunt Virus, carnation Italian ringspot Virus, and turnip crinkle Virus-associated RNA; the insect plus-strand RNA [(+)RNA] Viruses Flock House Virus and Nodamura Virus; and the double-stranded L-A Virus of yeast, are involved in interviral recombination events. Most interviral recombinants are minus-strand recombinant RNAs, and the junction sites are not randomly distributed, but there are certain hot spot regions. Formation of interviral recombinants in yeast and plants is accelerated by depletion of the cellular SERCA-like Pmr1 ATPase-driven Ca(2+)/Mn(2+) pump, regulating intracellular Ca(2+) and Mn(2+) influx into the Golgi apparatus from the cytosol. The interviral recombinants are generated by a template-switching mechanism during RNA replication by the viral replicase. Replication studies revealed that a group of interviral recombinants is replication competent in cell-free extracts, in yeast, and in the plant Nicotiana benthamiana We propose that there are major differences among the viral replicases to generate and maintain interviral recombinants. Altogether, the obtained data promote the model that host factors greatly contribute to the formation of recombinants among related and unrelated Viruses. This is the first time that a host factor's role in affecting interviral recombination is established.IMPORTANCE Viruses with RNA genomes are abundant, and their genomic sequences show astonishing variation. Genetic recombination in RNA Viruses is a major force behind their rapid evolution, enhanced pathogenesis, and adaptation to their hosts. We utilized a previously identified intracellular Ca(2+)/Mn(2+) pump-deficient yeast to search for interviral recombinants. Noninfectious viral replication systems were used to avoid generating unwanted infectious interviral recombinants. Altogether, interviral RNA recombinants were observed between plant and insect Viruses, and between a fungal double-stranded RNA (dsRNA) Virus and an insect Virus, in the yeast host. In addition, interviral recombinants between two plant Virus replicon RNAs were identified in N. benthamiana plants, in which the intracellular Ca(2+)/Mn(2+) pump was depleted. These findings underline the crucial role of the host in promoting RNA recombination among unrelated Viruses.

  • interviral recombination between plant insect and fungal rna Viruses role of the intracellular ca2 mn2 pump
    Journal of Virology, 2019
    Co-Authors: Nikolay Kovalev, Judit Pogany
    Abstract:

    Recombination is one of the driving forces of viral evolution. RNA recombination events among similar RNA Viruses are frequent, although RNA recombination could also take place among unrelated Viruses. In this paper, we have established efficient interviral recombination systems based on yeast and plants. We show that diverse RNA Viruses, including the plant Viruses tomato bushy stunt Virus, carnation Italian ringspot Virus, and turnip crinkle Virus-associated RNA; the insect plus-strand RNA [(+)RNA] Viruses Flock House Virus and Nodamura Virus; and the double-stranded L-A Virus of yeast, are involved in interviral recombination events. Most interviral recombinants are minus-strand recombinant RNAs, and the junction sites are not randomly distributed, but there are certain hot spot regions. Formation of interviral recombinants in yeast and plants is accelerated by depletion of the cellular SERCA-like Pmr1 ATPase-driven Ca2+/Mn2+ pump, regulating intracellular Ca2+ and Mn2+ influx into the Golgi apparatus from the cytosol. The interviral recombinants are generated by a template-switching mechanism during RNA replication by the viral replicase. Replication studies revealed that a group of interviral recombinants is replication competent in cell-free extracts, in yeast, and in the plant Nicotiana benthamiana We propose that there are major differences among the viral replicases to generate and maintain interviral recombinants. Altogether, the obtained data promote the model that host factors greatly contribute to the formation of recombinants among related and unrelated Viruses. This is the first time that a host factor's role in affecting interviral recombination is established.IMPORTANCE Viruses with RNA genomes are abundant, and their genomic sequences show astonishing variation. Genetic recombination in RNA Viruses is a major force behind their rapid evolution, enhanced pathogenesis, and adaptation to their hosts. We utilized a previously identified intracellular Ca2+/Mn2+ pump-deficient yeast to search for interviral recombinants. Noninfectious viral replication systems were used to avoid generating unwanted infectious interviral recombinants. Altogether, interviral RNA recombinants were observed between plant and insect Viruses, and between a fungal double-stranded RNA (dsRNA) Virus and an insect Virus, in the yeast host. In addition, interviral recombinants between two plant Virus replicon RNAs were identified in N. benthamiana plants, in which the intracellular Ca2+/Mn2+ pump was depleted. These findings underline the crucial role of the host in promoting RNA recombination among unrelated Viruses.

Peter D. Nagy - One of the best experts on this subject based on the ideXlab platform.

  • The TPR Domain in the Host Cyp40-like Cyclophilin Binds to the Viral Replication Protein and Inhibits the Assembly of the Tombusviral Replicase
    PLoS pathogens, 2012
    Co-Authors: Jing-yi Lin, Judit Pogany, Venugopal Mendu, Jun Qin, Peter D. Nagy
    Abstract:

    Replication of plus-stranded RNA Viruses is greatly affected by numerous host-coded proteins acting either as susceptibility or resistance factors. Previous genome-wide screens and global proteomics approaches with Tomato bushy stunt tombusVirus (TBSV) in a yeast model host revealed the involvement of cyclophilins, which are a large family of host prolyl isomerases, in TBSV replication. In this paper, we identified those members of the large cyclophilin family that interacted with the viral replication proteins and inhibited TBSV replication. Further characterization of the most effective cyclophilin, the Cyp40-like Cpr7p, revealed that it strongly inhibits many steps during TBSV replication in a cell-free replication assay. These steps include viral RNA recruitment inhibited via binding of Cpr7p to the RNA-binding region of the viral replication protein; the assembly of the viral replicase complex and viral RNA synthesis. Since the TPR (tetratricopeptide repeats) domain, but not the catalytic domain of Cpr7p is needed for the inhibitory effect on TBSV replication, it seems that the chaperone activity of Cpr7p provides the negative regulatory function. We also show that three Cyp40-like proteins from plants can inhibit TBSV replication in vitro and Cpr7p is also effective against Nodamura Virus, an insect pathogen. Overall, the current work revealed a role for Cyp40-like proteins and their TPR domains as regulators of RNA Virus replication.

  • The TPR Domain in the Host Cyp40-like Cyclophilin Binds to the Viral Replication Protein and Inhibits the Assembly of the Tombusviral Replicase
    2011
    Co-Authors: Jing-yi Lin, Judit Pogany, Venugopal Mendu, Jun Qin, Peter D. Nagy
    Abstract:

    Replication of plus-stranded RNA Viruses is greatly affected by numerous host-coded proteins acting either as susceptibility or resistance factors. Previous genome-wide screens and global proteomics approaches with Tomato bushy stunt tombusVirus (TBSV) in a yeast model host revealed the involvement of cyclophilins, which are a large family of host prolyl isomerases, in TBSV replication. In this paper, we identified those members of the large cyclophilin family that interacted with the viral replication proteins and inhibited TBSV replication. Further characterization of the most effective cyclophilin, the Cyp40-like Cpr7p, revealed that it strongly inhibits many steps during TBSV replication in a cell-free replication assay. These steps include viral RNA recruitment inhibited via binding of Cpr7p to the RNA-binding region of the viral replication protein; the assembly of the viral replicase complex and viral RNA synthesis. Since the TPR (tetratricopeptide repeats) domain, but not the catalytic domain of Cpr7p is needed for the inhibitory effect on TBSV replication, it seems that the chaperone activity of Cpr7p provides the negative regulatory function. We also show that three Cyp40-like proteins from plants can inhibit TBSV replication in vitro and Cpr7p is also effective against Nodamura Virus, an insect pathogen. Overall

Jing-yi Lin - One of the best experts on this subject based on the ideXlab platform.

  • The TPR Domain in the Host Cyp40-like Cyclophilin Binds to the Viral Replication Protein and Inhibits the Assembly of the Tombusviral Replicase
    PLoS pathogens, 2012
    Co-Authors: Jing-yi Lin, Judit Pogany, Venugopal Mendu, Jun Qin, Peter D. Nagy
    Abstract:

    Replication of plus-stranded RNA Viruses is greatly affected by numerous host-coded proteins acting either as susceptibility or resistance factors. Previous genome-wide screens and global proteomics approaches with Tomato bushy stunt tombusVirus (TBSV) in a yeast model host revealed the involvement of cyclophilins, which are a large family of host prolyl isomerases, in TBSV replication. In this paper, we identified those members of the large cyclophilin family that interacted with the viral replication proteins and inhibited TBSV replication. Further characterization of the most effective cyclophilin, the Cyp40-like Cpr7p, revealed that it strongly inhibits many steps during TBSV replication in a cell-free replication assay. These steps include viral RNA recruitment inhibited via binding of Cpr7p to the RNA-binding region of the viral replication protein; the assembly of the viral replicase complex and viral RNA synthesis. Since the TPR (tetratricopeptide repeats) domain, but not the catalytic domain of Cpr7p is needed for the inhibitory effect on TBSV replication, it seems that the chaperone activity of Cpr7p provides the negative regulatory function. We also show that three Cyp40-like proteins from plants can inhibit TBSV replication in vitro and Cpr7p is also effective against Nodamura Virus, an insect pathogen. Overall, the current work revealed a role for Cyp40-like proteins and their TPR domains as regulators of RNA Virus replication.

  • The TPR Domain in the Host Cyp40-like Cyclophilin Binds to the Viral Replication Protein and Inhibits the Assembly of the Tombusviral Replicase
    2011
    Co-Authors: Jing-yi Lin, Judit Pogany, Venugopal Mendu, Jun Qin, Peter D. Nagy
    Abstract:

    Replication of plus-stranded RNA Viruses is greatly affected by numerous host-coded proteins acting either as susceptibility or resistance factors. Previous genome-wide screens and global proteomics approaches with Tomato bushy stunt tombusVirus (TBSV) in a yeast model host revealed the involvement of cyclophilins, which are a large family of host prolyl isomerases, in TBSV replication. In this paper, we identified those members of the large cyclophilin family that interacted with the viral replication proteins and inhibited TBSV replication. Further characterization of the most effective cyclophilin, the Cyp40-like Cpr7p, revealed that it strongly inhibits many steps during TBSV replication in a cell-free replication assay. These steps include viral RNA recruitment inhibited via binding of Cpr7p to the RNA-binding region of the viral replication protein; the assembly of the viral replicase complex and viral RNA synthesis. Since the TPR (tetratricopeptide repeats) domain, but not the catalytic domain of Cpr7p is needed for the inhibitory effect on TBSV replication, it seems that the chaperone activity of Cpr7p provides the negative regulatory function. We also show that three Cyp40-like proteins from plants can inhibit TBSV replication in vitro and Cpr7p is also effective against Nodamura Virus, an insect pathogen. Overall

Andrew L Ball - One of the best experts on this subject based on the ideXlab platform.

  • Nodamura Virus nonstructural protein b2 can enhance viral rna accumulation in both mammalian and insect cells
    Journal of Virology, 2004
    Co-Authors: Kyle L Johnson, Duane B Price, Lance D Eckerle, Andrew L Ball
    Abstract:

    During infection of both vertebrate and invertebrate cell lines, the alphanodaVirus Nodamura Virus (NoV) expresses two nonstructural proteins of different lengths from the B2 open reading frame. The functions of these proteins have yet to be determined, but B2 of the related Flock House Virus suppresses RNA interference both in Drosophila cells and in transgenic plants. To examine whether the NoV B2 proteins had similar functions, we compared the replication of wild-type NoV RNA with that of mutants unable to make the B2 proteins. We observed a defect in the accumulation of mutant viral RNA that varied in extent from negligible in some cell lines (e.g., baby hamster kidney cells) to severe in others (e.g., human HeLa and Drosophila DL-1 cells). These results are consistent with the notion that the NoV B2 proteins act to circumvent an innate antiviral response such as RNA interference that differs in efficacy among different host cells.

  • Replication of Nodamura Virus after transfection of viral RNA into mammalian cells in culture
    1992
    Co-Authors: Andrew L Ball, Joseph M. Amann, Bonnie K. Garrett
    Abstract:

    Nodamura Virus (NOV) was purified from the hind limbs of infected suckling mice and used as a source of the two genomic RNAs of the Virus, RNA 1 and RNA 2. Upon transfection of the viral RNAs into baby hamster kidney (BHK21) cells in culture, vigorous RNA replication ensued and single-stranded RNAs 1 and 2 accumulated to reach an abundance which approximated that of the cellular rRNAs. Transient synthesis of a small subgenomic RNA (RNA 3) was also observed, and double-stranded versions of RNAs 1, 2, and 3 were detected. Three major viral proteins were synthesized in transfected cells. Protein A (about 115 kDa) and protein B (about 15 kDa) were made transiently at early times after transfection, whereas a large amount of protein alpha (43 kDa), the precursor to the two viral coat proteins, was made continuously starting later in the infectious cycle. When very low concentrations of viral RNAs were used for transfection, preferential replication of RNA 1 occurred. This result was attributed to segregation of the transfected viral RNAs to separate cells in culture and the subsequent replication and amplification of RNA 1 in cells that had received no RNA 2. Accordingly, multiple passages of the viral RNAs by transfection at the limit dilution resulted in the purification of RNA 1 free of RNA 2 and demonstrated that RNA 1 was capable of prolonged autonomous replication which was also accompanied by the continuous synthesis of RNA 3. In cells transfected with RNA 1 alone, protein alpha was not synthesized and proteins A and B were made continuously. Electron microscopi