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Nora Lopez - One of the best experts on this subject based on the ideXlab platform.
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development of a reverse genetic system to generate recombinant chimeric Tacaribe Virus that expresses junin Virus glycoproteins
Pathogenetics, 2020Co-Authors: Sabrina Foscaldi, Maria Eugenia Loureiro, Claudia Soledad Sepulveda, Carlos Adolfo Palacios, Maria Belen Forlenza, Nora LopezAbstract:MammarenaViruses are enveloped and segmented negative-stranded RNA Viruses that comprise several pathogenic members associated with severe human hemorrhagic fevers. Tacaribe Virus (TCRV) is the prototype for the New World group of mammarenaViruses and is not only naturally attenuated but also phylogenetically and antigenically related to all South American pathogenic mammarenaViruses, particularly the Junin Virus (JUNV), which is the etiological agent of Argentinian hemorrhagic fever (AHF). Moreover, since TCRV protects guinea pigs and non-human primates from lethal challenges with pathogenic strains of JUNV, it has already been considered as a potential live-attenuated Virus vaccine candidate against AHF. Here, we report the development of a reverse genetic system that relies on T7 polymerase-driven intracellular expression of the complementary copy (antigenome) of both viral S and L RNA segments. Using this approach, we successfully recovered recombinant TCRV (rTCRV) that displayed growth properties resembling those of authentic TCRV. We also generated a chimeric recombinant TCRV expressing the JUNV glycoproteins, which propagated similarly to wild-type rTCRV. Moreover, a controlled modification within the S RNA 5′ non-coding terminal sequence diminished rTCRV propagation in a cell-type dependent manner, giving rise to new perspectives where the incorporation of additional attenuation markers could contribute to develop safe rTCRV-based vaccines against pathogenic mammarenaViruses.
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Molecular Determinants of ArenaVirus Z Protein
2011Co-Authors: Polymerase L Binding, Maximiliano Wilda, Maria Eugenia Loureiro, Jesica Levingston M Macleod, Nora LopezAbstract:The arenaVirus Z is a zinc-binding RING protein that has been implicated in multiple functions during the viral life cycle. These roles of Z involve interactions with viral and cellular proteins that remain incompletely understood. In this regard, Z inhibits viral RNA transcription and replication through direct interaction with the viral L polymerase. Here, we defined the L-binding domain of Tacaribe Virus (TCRV) Z protein and the structural requirements mediating Z homo-oligomerization. By using site-directed mutagenesis, coimmuno-precipitation, and functional assays, we showed that residues R37, N39, W44, L50, and Y57, located around the zinc coordination site I, play a critical role in the Z-L interaction. We also found that Z protein from either TCRV or the pathogenic Junin Virus (JUNV) self-associates into oligomeric forms in mammalian cells. Importantly, mutation of the myristoylation site, the strictly conserved residue G at position 2, severely impaired the ability of both TCRV Z and JUNV Z to self-interact as well as their capacity to accumulate at the plasma membrane, strongly suggesting that Z homo-oligomerization is associated with its myristoylation and cell membrane targeting. In contrast, disruption of the RING structure or substitution of W44 or N39, which are critical for L protein recognition, did not affect Z self-binding. Overall, the data presented here indicate that homo-oligomerization is not a requirement for Z-L interaction or Z-mediated polymerase activity inhibition
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the ring domain and the l79 residue of z protein are involved in both the rescue of nucleocapsids and the incorporation of glycoproteins into infectious chimeric arenaVirus like particles
Journal of Virology, 2009Co-Authors: Juan Cruz Casabona, Maria Eugenia Loureiro, Jesica Levingston M Macleod, Guillermo A Gomez, Nora LopezAbstract:ArenaViruses, such as Tacaribe Virus (TacV) and its closely related pathogenic Junin Virus (JunV), are enveloped Viruses with a bipartite negative-sense RNA genome that encodes the nucleocapsid protein (N), the precursor of the envelope glycoprotein complex (GP), the polymerase (L), and a RING finger protein (Z), which is the driving force of arenaVirus budding. We have established a plasmid-based system which allowed the successful packaging of TacV-like nucleocapsids along with Z and GP of JunV into infectious Virus-like particles (VLPs). By coexpressing different combinations of the system components, followed by biochemical analysis of the VLPs, the requirements for the assembly of both N and GP into particles were defined. We found that coexpression of N with Z protein in the absence of minigenome and other viral proteins was sufficient to recruit N within lipid-enveloped Z-containing VLPs. In addition, whereas GP was not required for the incorporation of N, coexpression of N substantially enhanced the ratio of GP to Z into VLPs. Disruption of the RING structure or mutation of residue L79 to alanine within Z protein, although it had no effect on Z self-budding, severely impaired VLP infectivity. These mutations drastically altered intracellular Z-N interactions and the incorporation of both N and GP into VLPs. Our results support the conclusion that the interaction between Z and N is required for assembly of both the nucleocapsids and the glycoproteins into infectious arenaVirus budding particles.
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Tacaribe Virus z protein interacts with the l polymerase protein to inhibit viral rna synthesis
Journal of Virology, 2003Co-Authors: Rodrigo Jacamo, Nora Lopez, Maximiliano Wilda, Maria T FranzefernandezAbstract:Tacaribe Virus (TV) is the prototype of the New World group of arenaViruses. The TV genome encodes four proteins, the nucleoprotein (N), the glycoprotein precursor, the polymerase (L), and a small RING finger protein (Z). Using a reverse genetic system, we recently demonstrated that TV N and L are sufficient to drive transcription and full-cycle RNA replication mediated by TV-like RNAs and that Z is a powerful inhibitor of these processes (N. Lopez, R. Jacamo, and M. T. Franze-Fernandez, J. Virol. 65:12241-12251, 2001). In the present study we investigated whether Z might interact with either of the proteins, N and L, required for RNA synthesis. To that end, we used coimmunoprecipitation with monospecific antibodies against the viral proteins and coimmunoprecipitation with serum against glutathione S-transferase (GST) and binding to glutathione-Sepharose beads when Z was expressed as a fusion protein with GST. We demonstrated that Z interacted with L but not with N and that Z inhibitory activity was dependent on its ability to bind to L. We also evaluated the contribution of different Z regions to its binding ability and functional activity. We found that integrity of the RING structure is essential for Z binding to L and for Z inhibitory activity. Mutants with deletions at the N and C termini of Z showed that amino acids within the C-terminal region and immediately adjacent to the RING domain N terminus contribute to efficient Z-L interaction and are required for inhibitory activity. The data presented here provide the first evidence of an interaction between Z and L, suggesting that Z interferes with viral RNA synthesis by direct interaction with L. In addition, coimmunoprecipitation studies revealed a previously unreported interaction between N and L.
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transcription and rna replication of Tacaribe Virus genome and antigenome analogs require n and l proteins z protein is an inhibitor of these processes
Journal of Virology, 2001Co-Authors: Nora Lopez, Rodrigo Jacamo, Maria T FranzefernandezAbstract:Tacaribe Virus (TV), the prototype of the New World group of arenaViruses, comprises a single phylogenetic lineage together with four South American pathogenic producers of hemorrhagic disease. The TV genome consists of two single-stranded RNA segments called S and L. A reconstituted transcription-replication system based on plasmid-supplied TV-like RNAs and TV proteins was established. Plasmid expression was driven by T7 RNA polymerase supplied by a recombinant vaccinia Virus. Plasmids were constructed to produce TV S segment analogs containing the negative-sense copy of chloramphenicol acetyltransferase (CAT) flanked at the 5′ and 3′ termini by sequences corresponding to those of the 5′ and 3′ noncoding regions of the S genome (minigenome) or the S antigenome (miniantigenome). In cells expressing N and L proteins, input minigenome or miniantigenome produced, respectively, encapsidated miniantigenome or minigenome which in turn produced progeny minigenome or progeny miniantigenome. Both minigenome and miniantigenome in the presence of N and L mediated transcription, which was analyzed as CAT expression. Coexpression of the small RING finger Z (p11) protein was highly inhibitory to both transcription and replication mediated by the minigenome or the miniantigenome. The effect depended on synthesis of Z protein rather than on plasmid or the RNA and was not ascribed to decreased amounts of plasmid-supplied template or proteins (N or L). N and L proteins were sufficient to support full-cycle RNA replication of a plasmid-supplied S genome analog in which CAT replaced the N gene. Replication of this RNA was also inhibited by Z expression.
Maria T Franzefernandez - One of the best experts on this subject based on the ideXlab platform.
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Tacaribe Virus z protein interacts with the l polymerase protein to inhibit viral rna synthesis
Journal of Virology, 2003Co-Authors: Rodrigo Jacamo, Nora Lopez, Maximiliano Wilda, Maria T FranzefernandezAbstract:Tacaribe Virus (TV) is the prototype of the New World group of arenaViruses. The TV genome encodes four proteins, the nucleoprotein (N), the glycoprotein precursor, the polymerase (L), and a small RING finger protein (Z). Using a reverse genetic system, we recently demonstrated that TV N and L are sufficient to drive transcription and full-cycle RNA replication mediated by TV-like RNAs and that Z is a powerful inhibitor of these processes (N. Lopez, R. Jacamo, and M. T. Franze-Fernandez, J. Virol. 65:12241-12251, 2001). In the present study we investigated whether Z might interact with either of the proteins, N and L, required for RNA synthesis. To that end, we used coimmunoprecipitation with monospecific antibodies against the viral proteins and coimmunoprecipitation with serum against glutathione S-transferase (GST) and binding to glutathione-Sepharose beads when Z was expressed as a fusion protein with GST. We demonstrated that Z interacted with L but not with N and that Z inhibitory activity was dependent on its ability to bind to L. We also evaluated the contribution of different Z regions to its binding ability and functional activity. We found that integrity of the RING structure is essential for Z binding to L and for Z inhibitory activity. Mutants with deletions at the N and C termini of Z showed that amino acids within the C-terminal region and immediately adjacent to the RING domain N terminus contribute to efficient Z-L interaction and are required for inhibitory activity. The data presented here provide the first evidence of an interaction between Z and L, suggesting that Z interferes with viral RNA synthesis by direct interaction with L. In addition, coimmunoprecipitation studies revealed a previously unreported interaction between N and L.
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transcription and rna replication of Tacaribe Virus genome and antigenome analogs require n and l proteins z protein is an inhibitor of these processes
Journal of Virology, 2001Co-Authors: Nora Lopez, Rodrigo Jacamo, Maria T FranzefernandezAbstract:Tacaribe Virus (TV), the prototype of the New World group of arenaViruses, comprises a single phylogenetic lineage together with four South American pathogenic producers of hemorrhagic disease. The TV genome consists of two single-stranded RNA segments called S and L. A reconstituted transcription-replication system based on plasmid-supplied TV-like RNAs and TV proteins was established. Plasmid expression was driven by T7 RNA polymerase supplied by a recombinant vaccinia Virus. Plasmids were constructed to produce TV S segment analogs containing the negative-sense copy of chloramphenicol acetyltransferase (CAT) flanked at the 5′ and 3′ termini by sequences corresponding to those of the 5′ and 3′ noncoding regions of the S genome (minigenome) or the S antigenome (miniantigenome). In cells expressing N and L proteins, input minigenome or miniantigenome produced, respectively, encapsidated miniantigenome or minigenome which in turn produced progeny minigenome or progeny miniantigenome. Both minigenome and miniantigenome in the presence of N and L mediated transcription, which was analyzed as CAT expression. Coexpression of the small RING finger Z (p11) protein was highly inhibitory to both transcription and replication mediated by the minigenome or the miniantigenome. The effect depended on synthesis of Z protein rather than on plasmid or the RNA and was not ascribed to decreased amounts of plasmid-supplied template or proteins (N or L). N and L proteins were sufficient to support full-cycle RNA replication of a plasmid-supplied S genome analog in which CAT replaced the N gene. Replication of this RNA was also inhibited by Z expression.
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homologous and heterologous glycoproteins induce protection against junin Virus challenge in guinea pigs
Journal of General Virology, 2000Co-Authors: Nora Lopez, Rodrigo Jacamo, E B Damonte, Luis A Scolaro, Carlos Rossi, Nelida A Candurra, Carlos A Pujol, Maria T FranzefernandezAbstract:Tacaribe Virus (TACV) is an arenaVirus that is genetically and antigenically closely related to Junin Virus (JUNV), the aetiological agent of Argentine haemorrhagic fever (AHF). It is well established that TACV protects experimental animals fully against an otherwise lethal challenge with JUNV. To gain information on the nature of the antigens involved in cross-protection, recombinant vaccinia Viruses were constructed that express the glycoprotein precursor (VV-GTac) or the nucleocapsid protein (VV-N) of TACV. TACV proteins expressed by vaccinia Virus were indistinguishable from authentic Virus proteins by gel electrophoresis. Guinea pigs inoculated with VV-GTac or VV-N elicited antibodies that immunoprecipitated authentic TACV proteins. Antibodies generated by VV-GTac neutralized TACV infectivity. Levels of antibodies after priming and boosting with recombinant vaccinia Virus were comparable to those elicited in TACV infection. To evaluate the ability of recombinant vaccinia Virus to protect against experimental AHF, guinea pigs were challenged with lethal doses of JUNV. Fifty per cent of the animals immunized with VV-GTac survived, whereas all animals inoculated with VV-N or vaccinia Virus died. Having established that the heterologous glycoprotein protects against JUNV challenge, a recombinant vaccinia Virus was constructed that expresses JUNV glycoprotein precursor (VV-GJun). The size and reactivity to monoclonal antibodies of the vaccinia Virus-expressed and authentic JUNV glycoproteins were indistinguishable. Seventy-two per cent of the animals inoculated with two doses of VV-GJun survived lethal JUNV challenge. Protection with either VV-GJun or VV-GTac occurred in the presence of low or undetectable levels of neutralizing antibodies to JUNV.
John A. Lednicky - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE Isolation of Tacaribe Virus, a Caribbean ArenaVirus, from Host-Seeking Amblyomma americanum Ticks in Florida
2016Co-Authors: Katherine A. Sayler, Anthony F. Barbet, Rick Alleman, Julia C. Loeb, William L, John A. LednickyAbstract:Arenaviridae are a family of single stranded RNA Viruses of mammals and boid snakes. Twenty-nine distinct mammalian arenaViruses have been identified, many of which cause severe hemorrhagic disease in humans, particularly in parts of sub-Saharan Africa, and in Central and South America. Humans typically become infected with an arenaVirus through contact with excreta from infected rodents. Tacaribe Virus (TCRV) is an arenaVirus that was first isolated from bats and mosquitoes during a rabies surveillance survey conducted in Trinidad from 1956 to 1958. Tacaribe Virus is unusual because it has never been associated with a rodent host and since that one time isolation, the Virus has not been isolated from any vertebrate or invertebrate hosts. We report the re-isolation of the Virus from a pool of 100 host-seeking Amblyomma americanum (lone star ticks) collected in a Florida state park in 2012. TCRV was isolated in two cell lines and its complete genome was sequenced. The tick-derived isolate is nearly identical to the only remaining isolate from Trinidad (TRVL-11573), with 99.6 % nucleotide identity across th
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isolation of Tacaribe Virus a caribbean arenaVirus from host seeking amblyomma americanum ticks in florida
PLOS ONE, 2014Co-Authors: Katherine A. Sayler, Anthony F. Barbet, William L. Clapp, Julia C. Loeb, Casey A Chamberlain, R Alleman, John A. LednickyAbstract:Arenaviridae are a family of single stranded RNA Viruses of mammals and boid snakes. Twenty-nine distinct mammalian arenaViruses have been identified, many of which cause severe hemorrhagic disease in humans, particularly in parts of sub-Saharan Africa, and in Central and South America. Humans typically become infected with an arenaVirus through contact with excreta from infected rodents. Tacaribe Virus (TCRV) is an arenaVirus that was first isolated from bats and mosquitoes during a rabies surveillance survey conducted in Trinidad from 1956 to 1958. Tacaribe Virus is unusual because it has never been associated with a rodent host and since that one time isolation, the Virus has not been isolated from any vertebrate or invertebrate hosts. We report the re-isolation of the Virus from a pool of 100 host-seeking Amblyomma americanum (lone star ticks) collected in a Florida state park in 2012. TCRV was isolated in two cell lines and its complete genome was sequenced. The tick-derived isolate is nearly identical to the only remaining isolate from Trinidad (TRVL-11573), with 99.6% nucleotide identity across the genome. A quantitative RT-PCR assay was developed to test for viral RNA in host-seeking ticks collected from 3 Florida state parks. Virus RNA was detected in 56/500 (11.2%) of surveyed ticks. As this Virus was isolated from ticks that parasitize humans, the ability of the tick to transmit the Virus to people should be evaluated. Furthermore, reservoir hosts for the Virus need to be identified in order to develop risk assessment models of human infection.
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Sequence identity of the Florida isolate of Tacaribe Virus and the prototype Virus.
2014Co-Authors: Katherine A. Sayler, Anthony F. Barbet, Casey Chamberlain, William L. Clapp, Rick Alleman, Julia C. Loeb, John A. LednickyAbstract:Sequence identity of the Florida isolate of Tacaribe Virus and the prototype Virus.
Svenja Wolff - One of the best experts on this subject based on the ideXlab platform.
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The New World arenaVirus Tacaribe Virus induces caspase-dependent apoptosis in infected cells
The Journal of general virology, 2016Co-Authors: Svenja Wolff, Bjoern Meyer, Allison Groseth, David Jackson, Thomas Strecker, Andreas KaufmannAbstract:The Arenaviridae is a diverse and growing family of Viruses that already includes more than 25 distinct species. While some of these Viruses have a significant impact on public health, others appear to be non-pathogenic. At present little is known about the host cell responses to infection with different arenaViruses, particularly those found in the New World; however, apoptosis is known to play an important role in controlling infection of many Viruses. Here we show that infection with Tacaribe Virus (TCRV), which is widely considered the prototype for non-pathogenic arenaViruses, leads to stronger induction of apoptosis than does infection with its human-pathogenic relative Junin Virus. TCRV-induced apoptosis occurred in several cell types during late stages of infection and was shown to be caspase-dependent, involving the activation of caspases 3, 7, 8 and 9. Further, UV-inactivated TCRV did not induce apoptosis, indicating that the activation of this process is dependent on active viral replication/transcription. Interestingly, when apoptosis was inhibited, growth of TCRV was not enhanced, indicating that apoptosis does not have a direct negative effect on TCRV infection in vitro. Taken together, our data identify and characterize an important Virus–host cell interaction of the prototypic, non-pathogenic arenaVirus TCRV, which provides important insight into the growing field of arenaVirus research aimed at better understanding the diversity in responses to different arenaVirus infections and their functional consequences.
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Tacaribe Virus but Not Junin Virus Infection Induces Cytokine Release from Primary Human Monocytes and
2013Co-Authors: Allison Groseth, Svenja Wolff, Thomas Hoenen, Michaela Weber, Astrid Herwig, Stephan BeckerAbstract:The mechanisms underlying the development of disease during arenaVirus infection are poorly understood. However, common to all hemorrhagic fever diseases is the involvement of macrophages as primary target cells, suggesting that the immune response in these cells may be of paramount importance during infection. Thus, in order to identify features of the immune response that contribute to arenaVirus pathogenesis, we have examined the growth kinetics and cytokine profiles of two closely related New World arenaViruses, the apathogenic Tacaribe Virus (TCRV) and the hemorrhagic fever-causing Junin Virus (JUNV), in primary human monocytes and macrophages. Both Viruses grew robustly in VeroE6 cells; however, TCRV titres were decreased by approximately 10 fold compared to JUNV in both monocytes and macrophages. Infection of both monocytes and macrophages with TCRV also resulted in the release of high levels of IL-6, IL-10 and TNF-a, while levels of IFN-a, IFN-b and IL-12 were not affected. However, we could show that the presence of these cytokines had no direct effect on growth of either TCRV of JUNV in macrophages. Further analysis also showed that while the production of IL-6 and IL-10 are dependent on viral replication, production of TNF-a also occurs after exposure to UV-inactivated TCRV particles and is thus independent of productive Virus infection. Surprisingly, JUNV infection did not have an effect on any of the cytokines examined indicating that, in contrast to other viral hemorrhagic fever Viruses, macrophage-derived cytokine production is unlikely to play an active role in contributing to the cytokine dysregulation observed in JUNV infecte
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Tacaribe Virus but not junin Virus infection induces cytokine release from primary human monocytes and macrophages
PLOS Neglected Tropical Diseases, 2011Co-Authors: Allison Groseth, Svenja Wolff, Andreas Kaufmann, Thomas Hoenen, Michaela Weber, Astrid Herwig, Stephan BeckerAbstract:The mechanisms underlying the development of disease during arenaVirus infection are poorly understood. However, common to all hemorrhagic fever diseases is the involvement of macrophages as primary target cells, suggesting that the immune response in these cells may be of paramount importance during infection. Thus, in order to identify features of the immune response that contribute to arenaVirus pathogenesis, we have examined the growth kinetics and cytokine profiles of two closely related New World arenaViruses, the apathogenic Tacaribe Virus (TCRV) and the hemorrhagic fever-causing Junin Virus (JUNV), in primary human monocytes and macrophages. Both Viruses grew robustly in VeroE6 cells; however, TCRV titres were decreased by approximately 10 fold compared to JUNV in both monocytes and macrophages. Infection of both monocytes and macrophages with TCRV also resulted in the release of high levels of IL-6, IL-10 and TNF-α, while levels of IFN-α, IFN-β and IL-12 were not affected. However, we could show that the presence of these cytokines had no direct effect on growth of either TCRV of JUNV in macrophages. Further analysis also showed that while the production of IL-6 and IL-10 are dependent on viral replication, production of TNF-α also occurs after exposure to UV-inactivated TCRV particles and is thus independent of productive Virus infection. Surprisingly, JUNV infection did not have an effect on any of the cytokines examined indicating that, in contrast to other viral hemorrhagic fever Viruses, macrophage-derived cytokine production is unlikely to play an active role in contributing to the cytokine dysregulation observed in JUNV infected patients. Rather, these results suggest that an early, controlled immune response by infected macrophages may be critical for the successful control of infection of apathogenic Viruses and prevention of subsequent disease, including systemic cytokine dysregulation.
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efficient budding of the Tacaribe Virus matrix protein z requires the nucleoprotein
Journal of Virology, 2010Co-Authors: Svenja Wolff, Thomas Strecker, Thomas Hoenen, Stephan BeckerAbstract:The Z protein has been shown for several arenaViruses to serve as the viral matrix protein. As such, Z provides the principal force for the budding of Virus particles and is capable of forming Virus-like particles (VLPs) when expressed alone. For most arenaViruses, this activity has been shown to be linked to the presence of proline-rich late-domain motifs in the C terminus; however, for the New World arenaVirus Tacaribe Virus (TCRV), no such motif exists within Z. It was recently demonstrated that while TCRV Z is still capable of functioning as a matrix protein to induce the formation of VLPs, neither its ASAP motif, which replaces a canonical PT/SAP motif in related Viruses, nor its YxxL motif is involved in budding, leading to the suggestion that TCRV uses a novel budding mechanism. Here we show that in comparison to its closest relative, Junin Virus (JUNV), TCRV Z buds only weakly when expressed in isolation. While this budding activity is independent of the ASAP or YxxL motif, it is significantly enhanced by coexpression with the nucleoprotein (NP), an effect not seen with JUNV Z. Interestingly, both the ASAP and YxxL motifs of Z appear to be critical for the recruitment of NP into VLPs, as well as for the enhancement of TCRV Z-mediated budding. While it is known that TCRV budding remains dependent on the endosomal sorting complex required for transport, our findings provide further evidence that TCRV uses a budding mechanism distinct from that of other known arenaViruses and suggest an essential role for NP in this process.
Andreas Kaufmann - One of the best experts on this subject based on the ideXlab platform.
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The New World arenaVirus Tacaribe Virus induces caspase-dependent apoptosis in infected cells
The Journal of general virology, 2016Co-Authors: Svenja Wolff, Bjoern Meyer, Allison Groseth, David Jackson, Thomas Strecker, Andreas KaufmannAbstract:The Arenaviridae is a diverse and growing family of Viruses that already includes more than 25 distinct species. While some of these Viruses have a significant impact on public health, others appear to be non-pathogenic. At present little is known about the host cell responses to infection with different arenaViruses, particularly those found in the New World; however, apoptosis is known to play an important role in controlling infection of many Viruses. Here we show that infection with Tacaribe Virus (TCRV), which is widely considered the prototype for non-pathogenic arenaViruses, leads to stronger induction of apoptosis than does infection with its human-pathogenic relative Junin Virus. TCRV-induced apoptosis occurred in several cell types during late stages of infection and was shown to be caspase-dependent, involving the activation of caspases 3, 7, 8 and 9. Further, UV-inactivated TCRV did not induce apoptosis, indicating that the activation of this process is dependent on active viral replication/transcription. Interestingly, when apoptosis was inhibited, growth of TCRV was not enhanced, indicating that apoptosis does not have a direct negative effect on TCRV infection in vitro. Taken together, our data identify and characterize an important Virus–host cell interaction of the prototypic, non-pathogenic arenaVirus TCRV, which provides important insight into the growing field of arenaVirus research aimed at better understanding the diversity in responses to different arenaVirus infections and their functional consequences.
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Tacaribe Virus but not junin Virus infection induces cytokine release from primary human monocytes and macrophages
PLOS Neglected Tropical Diseases, 2011Co-Authors: Allison Groseth, Svenja Wolff, Andreas Kaufmann, Thomas Hoenen, Michaela Weber, Astrid Herwig, Stephan BeckerAbstract:The mechanisms underlying the development of disease during arenaVirus infection are poorly understood. However, common to all hemorrhagic fever diseases is the involvement of macrophages as primary target cells, suggesting that the immune response in these cells may be of paramount importance during infection. Thus, in order to identify features of the immune response that contribute to arenaVirus pathogenesis, we have examined the growth kinetics and cytokine profiles of two closely related New World arenaViruses, the apathogenic Tacaribe Virus (TCRV) and the hemorrhagic fever-causing Junin Virus (JUNV), in primary human monocytes and macrophages. Both Viruses grew robustly in VeroE6 cells; however, TCRV titres were decreased by approximately 10 fold compared to JUNV in both monocytes and macrophages. Infection of both monocytes and macrophages with TCRV also resulted in the release of high levels of IL-6, IL-10 and TNF-α, while levels of IFN-α, IFN-β and IL-12 were not affected. However, we could show that the presence of these cytokines had no direct effect on growth of either TCRV of JUNV in macrophages. Further analysis also showed that while the production of IL-6 and IL-10 are dependent on viral replication, production of TNF-α also occurs after exposure to UV-inactivated TCRV particles and is thus independent of productive Virus infection. Surprisingly, JUNV infection did not have an effect on any of the cytokines examined indicating that, in contrast to other viral hemorrhagic fever Viruses, macrophage-derived cytokine production is unlikely to play an active role in contributing to the cytokine dysregulation observed in JUNV infected patients. Rather, these results suggest that an early, controlled immune response by infected macrophages may be critical for the successful control of infection of apathogenic Viruses and prevention of subsequent disease, including systemic cytokine dysregulation.
