The Experts below are selected from a list of 51 Experts worldwide ranked by ideXlab platform
Sean P J Whelan - One of the best experts on this subject based on the ideXlab platform.
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protein expression redirects vesicular stomatitis virus RNA Synthesis to cytoplasmic inclusions
PLOS Pathogens, 2010Co-Authors: Bianca S Heinrich, David K Cureton, Amal A Rahmeh, Sean P J WhelanAbstract:Positive-strand and double-strand RNA viruses typically compartmentalize their replication machinery in infected cells. This is thought to shield viral RNA from detection by innate immune sensors and favor RNA Synthesis. The picture for the non-segmented negative-strand (NNS) RNA viruses, however, is less clear. Working with vesicular stomatitis virus (VSV), a prototype of the NNS RNA viruses, we examined the location of the viral replication machinery and RNA Synthesis in cells. By short-term labeling of viral RNA with 5′-bromouridine 5′-triphosphate (BrUTP), we demonstrate that primary mRNA Synthesis occurs throughout the host cell cytoplasm. Protein Synthesis results in the formation of inclusions that contain the viral RNA Synthesis machinery and become the predominant sites of mRNA Synthesis in the cell. Disruption of the microtubule network by treatment of cells with nocodazole leads to the accumulation of viral mRNA in discrete structures that decorate the surface of the inclusions. By pulse-chase analysis of the mRNA, we find that viral transcripts synthesized at the inclusions are transported away from the inclusions in a microtubule-dependent manner. Metabolic labeling of viral proteins revealed that inhibiting this transport step diminished the rate of translation. Collectively those data suggest that microtubule-dependent transport of viral mRNAs from inclusions facilitates their translation. Our experiments also show that during a VSV infection, protein Synthesis is required to redirect viral RNA Synthesis to intracytoplasmic inclusions. As viral RNA Synthesis is initially unrestricted, we speculate that its subsequent confinement to inclusions might reflect a cellular response to infection.
Peter Sarnow - One of the best experts on this subject based on the ideXlab platform.
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Viral RNA Synthesis
Human Enterovirus Infections, 1995Co-Authors: Kyle L. Johnson, Peter SarnowAbstract:This chapter summarizes what is known about how a single viral RNA molecule can be selectively amplified into thousands of RNA progeny in infected cells. It specifically provides the roles of viral proteins and RNA sequences in RNA replication, and describes the kinetics and products of RNA replication in infected cells. Next, it explains the sites and compositions of viral replication complexes (RCs) in infected cells. Then, the chapter discusses the models that have been proposed to explain how viral positive and negative RNA species are made by the viral RNA-dependent RNA polymerase. Finally, it describes the coupling between translation and replication processes in infected cells. Poliovirus is used as the prototype of an enterovirus because most of the research has been performed with poliovirus infected cell. To accomplish the unique task of RNA-dependent RNA polymerization in infected cells, enteroviruses encode several proteins required for viral RNA Synthesis. Open questions about the mechanism of viral Synthesis include the nature o f the RNA primers for positive- and negative-strand RNA Synthesis, the source of specificity for the viral template RNA, and the relationship between translation and RNA Synthesis, which may occur simultaneously in the infected host cell cytoplasm. Some of these questions may be studied with the recently discovered cellfree system.
Bianca S Heinrich - One of the best experts on this subject based on the ideXlab platform.
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protein expression redirects vesicular stomatitis virus RNA Synthesis to cytoplasmic inclusions
PLOS Pathogens, 2010Co-Authors: Bianca S Heinrich, David K Cureton, Amal A Rahmeh, Sean P J WhelanAbstract:Positive-strand and double-strand RNA viruses typically compartmentalize their replication machinery in infected cells. This is thought to shield viral RNA from detection by innate immune sensors and favor RNA Synthesis. The picture for the non-segmented negative-strand (NNS) RNA viruses, however, is less clear. Working with vesicular stomatitis virus (VSV), a prototype of the NNS RNA viruses, we examined the location of the viral replication machinery and RNA Synthesis in cells. By short-term labeling of viral RNA with 5′-bromouridine 5′-triphosphate (BrUTP), we demonstrate that primary mRNA Synthesis occurs throughout the host cell cytoplasm. Protein Synthesis results in the formation of inclusions that contain the viral RNA Synthesis machinery and become the predominant sites of mRNA Synthesis in the cell. Disruption of the microtubule network by treatment of cells with nocodazole leads to the accumulation of viral mRNA in discrete structures that decorate the surface of the inclusions. By pulse-chase analysis of the mRNA, we find that viral transcripts synthesized at the inclusions are transported away from the inclusions in a microtubule-dependent manner. Metabolic labeling of viral proteins revealed that inhibiting this transport step diminished the rate of translation. Collectively those data suggest that microtubule-dependent transport of viral mRNAs from inclusions facilitates their translation. Our experiments also show that during a VSV infection, protein Synthesis is required to redirect viral RNA Synthesis to intracytoplasmic inclusions. As viral RNA Synthesis is initially unrestricted, we speculate that its subsequent confinement to inclusions might reflect a cellular response to infection.
Kyung H. Choi - One of the best experts on this subject based on the ideXlab platform.
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Flavivirus RNA Synthesis in vitro
Methods, 2015Co-Authors: Radhakrishnan Padmanabhan, Ratree Takhampunya, Tadahisa Teramoto, Kyung H. ChoiAbstract:Establishment of in vitro systems to study mechanisms of RNA Synthesis for positive strand RNA viruses have been very useful in the past and have shed light on the composition of protein and RNA components, optimum conditions, the nature of the products formed, cis-acting RNA elements and trans-acting protein factors required for efficient Synthesis. In this review, we summarize our current understanding regarding the requirements for flavivirus RNA Synthesis in vitro. We describe details of reaction conditions, the specificity of template used by either the multi-component membrane-bound viral replicase complex or by purified, recombinant RNA-dependent RNA polymerase. We also discuss future perspectives to extend the boundaries of our knowledge.
Kyle L. Johnson - One of the best experts on this subject based on the ideXlab platform.
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Viral RNA Synthesis
Human Enterovirus Infections, 1995Co-Authors: Kyle L. Johnson, Peter SarnowAbstract:This chapter summarizes what is known about how a single viral RNA molecule can be selectively amplified into thousands of RNA progeny in infected cells. It specifically provides the roles of viral proteins and RNA sequences in RNA replication, and describes the kinetics and products of RNA replication in infected cells. Next, it explains the sites and compositions of viral replication complexes (RCs) in infected cells. Then, the chapter discusses the models that have been proposed to explain how viral positive and negative RNA species are made by the viral RNA-dependent RNA polymerase. Finally, it describes the coupling between translation and replication processes in infected cells. Poliovirus is used as the prototype of an enterovirus because most of the research has been performed with poliovirus infected cell. To accomplish the unique task of RNA-dependent RNA polymerization in infected cells, enteroviruses encode several proteins required for viral RNA Synthesis. Open questions about the mechanism of viral Synthesis include the nature o f the RNA primers for positive- and negative-strand RNA Synthesis, the source of specificity for the viral template RNA, and the relationship between translation and RNA Synthesis, which may occur simultaneously in the infected host cell cytoplasm. Some of these questions may be studied with the recently discovered cellfree system.
