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Frederick Arnaud - One of the best experts on this subject based on the ideXlab platform.
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A Paradigm for Virus–Host Coevolution: Sequential Counter-Adaptations between
2013Co-Authors: Exogenous Retroviruses, Frederick Arnaud, Marco Caporale, Mariana Varela, Roman Biek, Bernardo Chessa, Alberto Alberti, Matthew Golder, Manuela Mura, Ya-ping ZhangAbstract:Endogenous Retroviruses (ERVs) are remnants of ancient retroviral infections of the host germline transmitted vertically from generation to generation. It is hypothesized that some ERVs are used by the host as restriction factors to block the infection of pathogenic Retroviruses. Indeed, some ERVs efficiently interfere with the replication of related exogenous Retroviruses. However, data suggesting that these mechanisms have influenced the coevolution of endogenous and/or exogenous Retroviruses and their hosts have been more difficult to obtain. Sheep are an interesting model system to study retrovirus-host coevolution because of the coexistence in this animal species of two exogenous (i.e., horizontally transmitted) oncogenic Retroviruses, Jaagsiekte sheep retrovirus and Enzootic nasal tumor virus, with highly related and biologically active endogenous Retroviruses (enJSRVs). Here, we isolated an
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Endogenous Retroviruses
Cellular and Molecular Life Sciences, 2008Co-Authors: Frederick Arnaud, M. Varela, T. E. Spencer, Massimo PalmariniAbstract:Sheep betaRetroviruses offer a unique model system to study the complex interaction between Retroviruses and their host. Jaagsiekte sheep retrovirus (JSRV) is a pathogenic exogenous retrovirus and the causative agent of ovine pulmonary adenocarcinoma. The sheep genome contains at least 27 copies of endogenous Retroviruses (enJSRVs) highly related to JSRV. enJSRVs have played several roles in the evolution of the domestic sheep as they are able to block the JSRV replication cycle and play a critical role in sheep conceptus development and placental morphogenesis. Available data strongly suggest that some dominant negative enJSRV proviruses (i.e. able to block JSRV replication) have been positively selected during evolution. Interestingly, viruses escaping the transdominant enJSRV loci have recently emerged (less than 200 years ago). Thus, endogenization of these Retroviruses may still be occurring today. Therefore, sheep provide an exciting and unique system to study retrovirus-host coevolution. (Part of a Multi-author Review)
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Endogenous Retroviruses
Cellular and Molecular Life Sciences, 2008Co-Authors: Frederick Arnaud, M. Varela, T. E. Spencer, Massimo PalmariniAbstract:Sheep betaRetroviruses offer a unique model system to study the complex interaction between Retroviruses and their host. Jaagsiekte sheep retrovirus (JSRV) is a pathogenic exogenous retrovirus and the causative agent of ovine pulmonary adenocarcinoma. The sheep genome contains at least 27 copies of endogenous Retroviruses (enJSRVs) highly related to JSRV. enJSRVs have played several roles in the evolution of the domestic sheep as they are able to block the JSRV replication cycle and play a critical role in sheep conceptus development and placental morphogenesis. Available data strongly suggest that some dominant negative enJSRV proviruses (i.e. able to block JSRV replication) have been positively selected during evolution. Interestingly, viruses escaping the transdominant enJSRV loci have recently emerged (less than 200 years ago). Thus, endogenization of these Retroviruses may still be occurring today. Therefore, sheep provide an exciting and unique system to study retrovirus-host coevolution.
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a paradigm for virus host coevolution sequential counter adaptations between endogenous and exogenous Retroviruses
PLOS Pathogens, 2007Co-Authors: Frederick Arnaud, Marco Caporale, Mariana Varela, Roman Biek, Bernardo Chessa, Alberto Alberti, Matthew Golder, Manuela Mura, Ya-ping Zhang, Li YuAbstract:Endogenous Retroviruses (ERVs) are remnants of ancient retroviral infections of the host germline transmitted vertically from generation to generation. It is hypothesized that some ERVs are used by the host as restriction factors to block the infection of pathogenic Retroviruses. Indeed, some ERVs efficiently interfere with the replication of related exogenous Retroviruses. However, data suggesting that these mechanisms have influenced the coevolution of endogenous and/or exogenous Retroviruses and their hosts have been more difficult to obtain. Sheep are an interesting model system to study retrovirus-host coevolution because of the coexistence in this animal species of two exogenous (i.e., horizontally transmitted) oncogenic Retroviruses, Jaagsiekte sheep retrovirus and Enzootic nasal tumor virus, with highly related and biologically active endogenous Retroviruses (enJSRVs). Here, we isolated and characterized the evolutionary history and molecular virology of 27 enJSRV proviruses. enJSRVs have been integrating in the host genome for the last 5–7 million y. Two enJSRV proviruses (enJS56A1 and enJSRV-20), which entered the host genome within the last 3 million y (before and during speciation within the genus Ovis), acquired in two temporally distinct events a defective Gag polyprotein resulting in a transdominant phenotype able to block late replication steps of related exogenous Retroviruses. Both transdominant proviruses became fixed in the host genome before or around sheep domestication (; 9,000 y ago). Interestingly, a provirus escaping the transdominant enJSRVs has emerged very recently, most likely within the last 200 y. Thus, we determined sequentially distinct events during evolution that are indicative of an evolutionary antagonism between endogenous and exogenous Retroviruses. This study strongly suggests that endogenization and selection of ERVs acting as restriction factors is a mechanism used by the host to fight retroviral infections.
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A paradigm for virus-host coevolution: sequential counter-adaptations between endogenous and exogenous Retroviruses
PLoS Pathogens, 2007Co-Authors: Frederick Arnaud, Marco Caporale, Mariana Varela, Roman Biek, Bernardo Chessa, Alberto Alberti, Matthew Golder, Manuela Mura, Ya-ping Zhang, Filipe PereiraAbstract:Endogenous Retroviruses (ERVs) are remnants of ancient retroviral infections of the host germline transmitted vertically from generation to generation. It is hypothesized that some ERVs are used by the host as restriction factors to block the infection of pathogenic Retroviruses. Indeed, some ERVs efficiently interfere with the replication of related exogenous Retroviruses. However, data suggesting that these mechanisms have influenced the coevolution of endogenous and/or exogenous Retroviruses and their hosts have been more difficult to obtain. Sheep are an interesting model system to study retrovirus-host coevolution because of the coexistence in this animal species of two exogenous (i.e., horizontally transmitted) oncogenic Retroviruses, Jaagsiekte sheep retrovirus and Enzootic nasal tumor virus, with highly related and biologically active endogenous Retroviruses (enJSRVs). Here, we isolated and characterized the evolutionary history and molecular virology of 27 enJSRV proviruses. enJSRVs have been integrating in the host genome for the last 5-7 million y. Two enJSRV proviruses (enJS56A1 and enJSRV-20), which entered the host genome within the last 3 million y (before and during speciation within the genus Ovis), acquired in two temporally distinct events a defective Gag polyprotein resulting in a transdominant phenotype able to block late replication steps of related exogenous Retroviruses. Both transdominant proviruses became fixed in the host genome before or around sheep domestication (approximately 9,000 y ago). Interestingly, a provirus escaping the transdominant enJSRVs has emerged very recently, most likely within the last 200 y. Thus, we determined sequentially distinct events during evolution that are indicative of an evolutionary antagonism between endogenous and exogenous Retroviruses. This study strongly suggests that endogenization and selection of ERVs acting as restriction factors is a mechanism used by the host to fight retroviral infections.
Carlos V. Paya - One of the best experts on this subject based on the ideXlab platform.
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Potential Medical Impact of Endogenous Retroviruses
Xenotransplantation, 2001Co-Authors: Rima Abu-nader, Carlos V. PayaAbstract:The recent in vitro observation that porcine endogenous Retroviruses (PERV) can infect human cells has ignited tremendous fear among investigators in the xenotransplantation field and health officials. This chapter reviews the available experience with other endogenous Retroviruses in different animal situations, with the aim of better understanding the potential impact of such organisms in the field of xenotransplantation. All mammals that have been examined so far, including pigs and baboons, have endogenous retrovirus DNA sequences integrated in their genomes. Although transmitted in the germ line, they exhibit a very significant sequence homology to exogenous Retroviruses. The true source of endogenous Retroviruses remains to be elucidated. One hypothesis is that they are viral remnants of remote infections with exogenous forms of the virus. Alternative explanations include that Retroviruses may be derived from retrotransposons or that endogenous Retroviruses are the precursors of exogenous retroviral agents. The majority of endogenous Retroviruses act as colonizers in the germ line of the host and are noninfectious. The exact functions of the remaining "competent" or partially defective endogenous Retroviruses remain enigmatic. It is speculated that, among a number of possible functions, they may enhance the pathogenicity of exogenous Retroviruses by the recombination and production of a hybrid virus with altered receptor specificity and species tropism, now capable of infecting a new range of hosts. New animal viruses are being discovered on a regular basis, as detection methods are becoming more sophisticated. Similarly, many more animal endogenous Retroviruses are yet to be discovered and fully characterized.
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Potential Medical Impact of Endogenous Retroviruses
Xenotransplantation, 2001Co-Authors: Rima Abu-nader, Carlos V. PayaAbstract:The recent in vitro observation that porcine endogenous Retroviruses (PERV) can infect human cells has ignited tremendous fear among investigators in the xenotransplantation field and health officials. This chapter reviews the available experience with other endogenous Retroviruses in different animal situations, with the aim of better understanding the potential impact of such organisms in the field of xenotransplantation. All mammals that have been examined so far, including pigs and baboons, have endogenous retrovirus DNA sequences integrated in their genomes. Although transmitted in the germ line, they exhibit a very significant sequence homology to exogenous Retroviruses. The true source of endogenous Retroviruses remains to be elucidated. One hypothesis is that they are viral remnants of remote infections with exogenous forms of the virus. Alternative explanations include that Retroviruses may be derived from retrotransposons or that endogenous Retroviruses are the precursors of exogenous retroviral agents. The majority of endogenous Retroviruses act as colonizers in the germ line of the host and are noninfectious. The exact functions of the remaining "competent" or partially defective endogenous Retroviruses remain enigmatic. It is speculated that, among a number of possible functions, they may enhance the pathogenicity of exogenous Retroviruses by the recombination and production of a hybrid virus with altered receptor specificity and species tropism, now capable of infecting a new range of hosts. New animal viruses are being discovered on a regular basis, as detection methods are becoming more sophisticated. Similarly, many more animal endogenous Retroviruses are yet to be discovered and fully characterized.
Clausen J - One of the best experts on this subject based on the ideXlab platform.
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Endogenous Retroviruses and multiple sclerosis
Journal of NeuroVirology, 2000Co-Authors: Rasmussen Hb, Lucotte G, Clausen JAbstract:Endogenous Retroviruses are normal constituents in vertebrate genomes. They have been associated with various diseases of presumed autoimmune etiology. However, conclusive evidence of their signi®cance as susceptibility factors in these diseases is still lacking. In our laboratory we have focused attention upon endogenous Retroviruses as candidate genes in multiple sclerosis. In this communication we describe general properties of endogenous Retroviruses and we present observations from some of our studies. Journal of NeuroVirology (2000) 6, S80 ± S84.
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Endogenous Retroviruses and multiple sclerosis.
Journal of neurovirology, 2000Co-Authors: Lucotte G, Clausen JAbstract:Endogenous Retroviruses are normal constituents in vertebrate genomes. They have been associated with various diseases of presumed autoimmune etiology. However, conclusive evidence of their significance as susceptibility factors in these diseases is still lacking. In our laboratory we have focused attention upon endogenous Retroviruses as candidate genes in multiple sclerosis. In this communication we describe general properties of endogenous Retroviruses and we present observations from some of our studies.
Ya-ping Zhang - One of the best experts on this subject based on the ideXlab platform.
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A Paradigm for Virus–Host Coevolution: Sequential Counter-Adaptations between
2013Co-Authors: Exogenous Retroviruses, Frederick Arnaud, Marco Caporale, Mariana Varela, Roman Biek, Bernardo Chessa, Alberto Alberti, Matthew Golder, Manuela Mura, Ya-ping ZhangAbstract:Endogenous Retroviruses (ERVs) are remnants of ancient retroviral infections of the host germline transmitted vertically from generation to generation. It is hypothesized that some ERVs are used by the host as restriction factors to block the infection of pathogenic Retroviruses. Indeed, some ERVs efficiently interfere with the replication of related exogenous Retroviruses. However, data suggesting that these mechanisms have influenced the coevolution of endogenous and/or exogenous Retroviruses and their hosts have been more difficult to obtain. Sheep are an interesting model system to study retrovirus-host coevolution because of the coexistence in this animal species of two exogenous (i.e., horizontally transmitted) oncogenic Retroviruses, Jaagsiekte sheep retrovirus and Enzootic nasal tumor virus, with highly related and biologically active endogenous Retroviruses (enJSRVs). Here, we isolated an
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a paradigm for virus host coevolution sequential counter adaptations between endogenous and exogenous Retroviruses
PLOS Pathogens, 2007Co-Authors: Frederick Arnaud, Marco Caporale, Mariana Varela, Roman Biek, Bernardo Chessa, Alberto Alberti, Matthew Golder, Manuela Mura, Ya-ping Zhang, Li YuAbstract:Endogenous Retroviruses (ERVs) are remnants of ancient retroviral infections of the host germline transmitted vertically from generation to generation. It is hypothesized that some ERVs are used by the host as restriction factors to block the infection of pathogenic Retroviruses. Indeed, some ERVs efficiently interfere with the replication of related exogenous Retroviruses. However, data suggesting that these mechanisms have influenced the coevolution of endogenous and/or exogenous Retroviruses and their hosts have been more difficult to obtain. Sheep are an interesting model system to study retrovirus-host coevolution because of the coexistence in this animal species of two exogenous (i.e., horizontally transmitted) oncogenic Retroviruses, Jaagsiekte sheep retrovirus and Enzootic nasal tumor virus, with highly related and biologically active endogenous Retroviruses (enJSRVs). Here, we isolated and characterized the evolutionary history and molecular virology of 27 enJSRV proviruses. enJSRVs have been integrating in the host genome for the last 5–7 million y. Two enJSRV proviruses (enJS56A1 and enJSRV-20), which entered the host genome within the last 3 million y (before and during speciation within the genus Ovis), acquired in two temporally distinct events a defective Gag polyprotein resulting in a transdominant phenotype able to block late replication steps of related exogenous Retroviruses. Both transdominant proviruses became fixed in the host genome before or around sheep domestication (; 9,000 y ago). Interestingly, a provirus escaping the transdominant enJSRVs has emerged very recently, most likely within the last 200 y. Thus, we determined sequentially distinct events during evolution that are indicative of an evolutionary antagonism between endogenous and exogenous Retroviruses. This study strongly suggests that endogenization and selection of ERVs acting as restriction factors is a mechanism used by the host to fight retroviral infections.
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A paradigm for virus-host coevolution: sequential counter-adaptations between endogenous and exogenous Retroviruses
PLoS Pathogens, 2007Co-Authors: Frederick Arnaud, Marco Caporale, Mariana Varela, Roman Biek, Bernardo Chessa, Alberto Alberti, Matthew Golder, Manuela Mura, Ya-ping Zhang, Filipe PereiraAbstract:Endogenous Retroviruses (ERVs) are remnants of ancient retroviral infections of the host germline transmitted vertically from generation to generation. It is hypothesized that some ERVs are used by the host as restriction factors to block the infection of pathogenic Retroviruses. Indeed, some ERVs efficiently interfere with the replication of related exogenous Retroviruses. However, data suggesting that these mechanisms have influenced the coevolution of endogenous and/or exogenous Retroviruses and their hosts have been more difficult to obtain. Sheep are an interesting model system to study retrovirus-host coevolution because of the coexistence in this animal species of two exogenous (i.e., horizontally transmitted) oncogenic Retroviruses, Jaagsiekte sheep retrovirus and Enzootic nasal tumor virus, with highly related and biologically active endogenous Retroviruses (enJSRVs). Here, we isolated and characterized the evolutionary history and molecular virology of 27 enJSRV proviruses. enJSRVs have been integrating in the host genome for the last 5-7 million y. Two enJSRV proviruses (enJS56A1 and enJSRV-20), which entered the host genome within the last 3 million y (before and during speciation within the genus Ovis), acquired in two temporally distinct events a defective Gag polyprotein resulting in a transdominant phenotype able to block late replication steps of related exogenous Retroviruses. Both transdominant proviruses became fixed in the host genome before or around sheep domestication (approximately 9,000 y ago). Interestingly, a provirus escaping the transdominant enJSRVs has emerged very recently, most likely within the last 200 y. Thus, we determined sequentially distinct events during evolution that are indicative of an evolutionary antagonism between endogenous and exogenous Retroviruses. This study strongly suggests that endogenization and selection of ERVs acting as restriction factors is a mechanism used by the host to fight retroviral infections.
Rima Abu-nader - One of the best experts on this subject based on the ideXlab platform.
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Potential Medical Impact of Endogenous Retroviruses
Xenotransplantation, 2001Co-Authors: Rima Abu-nader, Carlos V. PayaAbstract:The recent in vitro observation that porcine endogenous Retroviruses (PERV) can infect human cells has ignited tremendous fear among investigators in the xenotransplantation field and health officials. This chapter reviews the available experience with other endogenous Retroviruses in different animal situations, with the aim of better understanding the potential impact of such organisms in the field of xenotransplantation. All mammals that have been examined so far, including pigs and baboons, have endogenous retrovirus DNA sequences integrated in their genomes. Although transmitted in the germ line, they exhibit a very significant sequence homology to exogenous Retroviruses. The true source of endogenous Retroviruses remains to be elucidated. One hypothesis is that they are viral remnants of remote infections with exogenous forms of the virus. Alternative explanations include that Retroviruses may be derived from retrotransposons or that endogenous Retroviruses are the precursors of exogenous retroviral agents. The majority of endogenous Retroviruses act as colonizers in the germ line of the host and are noninfectious. The exact functions of the remaining "competent" or partially defective endogenous Retroviruses remain enigmatic. It is speculated that, among a number of possible functions, they may enhance the pathogenicity of exogenous Retroviruses by the recombination and production of a hybrid virus with altered receptor specificity and species tropism, now capable of infecting a new range of hosts. New animal viruses are being discovered on a regular basis, as detection methods are becoming more sophisticated. Similarly, many more animal endogenous Retroviruses are yet to be discovered and fully characterized.
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Potential Medical Impact of Endogenous Retroviruses
Xenotransplantation, 2001Co-Authors: Rima Abu-nader, Carlos V. PayaAbstract:The recent in vitro observation that porcine endogenous Retroviruses (PERV) can infect human cells has ignited tremendous fear among investigators in the xenotransplantation field and health officials. This chapter reviews the available experience with other endogenous Retroviruses in different animal situations, with the aim of better understanding the potential impact of such organisms in the field of xenotransplantation. All mammals that have been examined so far, including pigs and baboons, have endogenous retrovirus DNA sequences integrated in their genomes. Although transmitted in the germ line, they exhibit a very significant sequence homology to exogenous Retroviruses. The true source of endogenous Retroviruses remains to be elucidated. One hypothesis is that they are viral remnants of remote infections with exogenous forms of the virus. Alternative explanations include that Retroviruses may be derived from retrotransposons or that endogenous Retroviruses are the precursors of exogenous retroviral agents. The majority of endogenous Retroviruses act as colonizers in the germ line of the host and are noninfectious. The exact functions of the remaining "competent" or partially defective endogenous Retroviruses remain enigmatic. It is speculated that, among a number of possible functions, they may enhance the pathogenicity of exogenous Retroviruses by the recombination and production of a hybrid virus with altered receptor specificity and species tropism, now capable of infecting a new range of hosts. New animal viruses are being discovered on a regular basis, as detection methods are becoming more sophisticated. Similarly, many more animal endogenous Retroviruses are yet to be discovered and fully characterized.