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The Journal of General Virology Dec 2021Viruses in the family are found in a wide variety of vertebrate hosts. Enveloped virions are 80-100 nm in diameter with an inner core containing the viral genome and...
Viruses in the family are found in a wide variety of vertebrate hosts. Enveloped virions are 80-100 nm in diameter with an inner core containing the viral genome and replicative enzymes. Core morphology is often characteristic for viruses within the same genus. Replication involves reverse transcription and integration into host cell DNA, resulting in a provirus. Integration into germline cells can result in a heritable provirus known as an endogenous retrovirus. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the family , which is available at ictv.global/report/retroviridae.
Topics: Animals; DNA Viruses; Genome, Viral; Host Specificity; Retroviridae; Vertebrates; Virion; Virus Replication
PubMed: 34939563
DOI: 10.1099/jgv.0.001712 -
Virology Mar 2018Spumaretroviruses, commonly referred to as foamy viruses, are complex retroviruses belonging to the subfamily Spumaretrovirinae, family Retroviridae, which naturally... (Review)
Review
Spumaretroviruses, commonly referred to as foamy viruses, are complex retroviruses belonging to the subfamily Spumaretrovirinae, family Retroviridae, which naturally infect a variety of animals including nonhuman primates (NHPs). Additionally, cross-species transmissions of simian foamy viruses (SFVs) to humans have occurred following exposure to tissues of infected NHPs. Recent research has led to the identification of previously unknown exogenous foamy viruses, and to the discovery of endogenous spumaretrovirus sequences in a variety of host genomes. Here, we describe an updated spumaretrovirus taxonomy that has been recently accepted by the International Committee on Taxonomy of Viruses (ICTV) Executive Committee, and describe a virus nomenclature that is generally consistent with that used for other retroviruses, such as lentiviruses and deltaretroviruses. This taxonomy can be applied to distinguish different, but closely related, primate (e.g., human, ape, simian) foamy viruses as well as those from other hosts. This proposal accounts for host-virus co-speciation and cross-species transmission.
Topics: Animals; Host Specificity; Humans; Phylogeny; Primates; Retroviridae Infections; Spumavirus
PubMed: 29407373
DOI: 10.1016/j.virol.2017.12.035 -
Virology May 2015The APOBEC family of single-stranded DNA cytosine deaminases comprises a formidable arm of the vertebrate innate immune system. Pre-vertebrates express a single APOBEC,... (Review)
Review
The APOBEC family of single-stranded DNA cytosine deaminases comprises a formidable arm of the vertebrate innate immune system. Pre-vertebrates express a single APOBEC, whereas some mammals produce as many as 11 enzymes. The APOBEC3 subfamily displays both copy number variation and polymorphisms, consistent with ongoing pathogenic pressures. These enzymes restrict the replication of many DNA-based parasites, such as exogenous viruses and endogenous transposable elements. APOBEC1 and activation-induced cytosine deaminase (AID) have specialized functions in RNA editing and antibody gene diversification, respectively, whereas APOBEC2 and APOBEC4 appear to have different functions. Nevertheless, the APOBEC family protects against both periodic viral zoonoses as well as exogenous and endogenous parasite replication. This review highlights viral pathogens that are restricted by APOBEC enzymes, but manage to escape through unique mechanisms. The sensitivity of viruses that lack counterdefense measures highlights the need to develop APOBEC-enabling small molecules as a new class of anti-viral drugs.
Topics: Animals; Cytidine Deaminase; DNA Viruses; Host-Pathogen Interactions; Humans; Multigene Family; RNA, Viral; Retroviridae; Vertebrates
PubMed: 25818029
DOI: 10.1016/j.virol.2015.03.012 -
Viruses Dec 2021Retroviruses have a very complex and tightly controlled life cycle which has been studied intensely for decades. After a virus enters the cell, it reverse-transcribes... (Review)
Review
Retroviruses have a very complex and tightly controlled life cycle which has been studied intensely for decades. After a virus enters the cell, it reverse-transcribes its genome, which is then integrated into the host genome, and subsequently all structural and regulatory proteins are transcribed and translated. The proteins, along with the viral genome, assemble into a new virion, which buds off the host cell and matures into a newly infectious virion. If any one of these steps are faulty, the virus cannot produce infectious viral progeny. Recent advances in structural and molecular techniques have made it possible to better understand this class of viruses, including details about how they regulate and coordinate the different steps of the virus life cycle. In this review we summarize the molecular analysis of the assembly and maturation steps of the life cycle by providing an overview on structural and biochemical studies to understand these processes. We also outline the differences between various retrovirus families with regards to these processes.
Topics: Capsid; Cryoelectron Microscopy; Genome, Viral; HIV-1; Humans; Models, Molecular; Retroviridae; Virion; Virus Assembly
PubMed: 35062258
DOI: 10.3390/v14010054 -
Gene Nov 2021Although seen as a revolution in modern science, gene therapy has been plagued by failed clinical trials and controversial ethics in the last thirty years. Moreover,... (Review)
Review
Although seen as a revolution in modern science, gene therapy has been plagued by failed clinical trials and controversial ethics in the last thirty years. Moreover, there is no comprehensive, in-depth, high-quality analysis of global gene therapy patents. This paper proposes a method to correctly retrieve patents to address the issue and use it for the patent landscape. The results show the global patent landscape of gene therapy, with the United States dominating the field, while China has emerged as a leader in recent years. For various reasons, the EU, Korea, and Japan lag in the development of patented technologies. China has edged closer to the US in both live and indefinite patents, with the Chinese Academy of Military Medical Sciences and the Chinese Academy of Sciences leading the way, surpassing primary applicants such as the US Department of Health and Human Services, the University of California, and the University of Pennsylvania. The study also reveals four broad categories of technologies that have been extensively studied in gene therapy: basic biology of the gene and diseases, diseases being treated, gene delivery methods, and potential adverse events. What is more, Adeno-Associated Virus, Retrovirus, and Lentivirus are the most prevalent gene therapy delivery vectors after 2014. The industrial development trend revealed in this paper can provide an evidence-based basis for scientific research management and decision-making.
Topics: China; Dependovirus; European Union; Genetic Therapy; Genetic Vectors; Humans; Japan; Lentivirus; Patents as Topic; Republic of Korea; Retroviridae; United States
PubMed: 34371094
DOI: 10.1016/j.gene.2021.145889 -
Current Opinion in Virology Jun 2016Retroviruses such as HIV-1 assemble and bud from infected cells in an immature, non-infectious form. Subsequently, a series of proteolytic cleavages catalysed by the... (Review)
Review
Retroviruses such as HIV-1 assemble and bud from infected cells in an immature, non-infectious form. Subsequently, a series of proteolytic cleavages catalysed by the viral protease leads to a spectacular structural rearrangement of the viral particle into a mature form that is competent to fuse with and infect a new cell. Maturation involves changes in the structures of protein domains, in the interactions between protein domains, and in the architecture of the viral components that are assembled by the proteins. Tight control of proteolytic cleavages at different sites is required for successful maturation, and the process is a major target of antiretroviral drugs. Here we will describe what is known about the structures of immature and mature retrovirus particles, and about the maturation process by which one transitions into the other. Despite a wealth of available data, fundamental questions about retroviral maturation remain unanswered.
Topics: Capsid Proteins; HIV-1; Humans; Peptide Hydrolases; Proteolysis; Retroviridae; Viral Proteins; Virion; Virus Assembly; gag Gene Products, Human Immunodeficiency Virus
PubMed: 27010119
DOI: 10.1016/j.coviro.2016.02.008 -
Clinical Microbiology and Infection :... Apr 2016Retroviruses, including the human immunodeficiency virus (HIV), are notorious for two essential steps of their viral replication: reverse transcription and integration.... (Review)
Review
Retroviruses, including the human immunodeficiency virus (HIV), are notorious for two essential steps of their viral replication: reverse transcription and integration. This latter property is considered to be essential for productive replication and ensures the stable long-term insertion of the viral genome sequence in the host chromatin, thereby leading to the life-long association of the virus with the infected cell. Using HIV as a prototypic example, the present review aims to provide an overview of how and where integration occurs, as well as presenting general consequences for both the virus and the infected host.
Topics: Host-Pathogen Interactions; Humans; Retroviridae; Virus Integration
PubMed: 27107301
DOI: 10.1016/j.cmi.2016.02.013 -
Viruses Jul 2020Retroviruses are major causes of disease in animals and human. Better understanding of the initial host immune response to these viruses could provide insight into how... (Review)
Review
Retroviruses are major causes of disease in animals and human. Better understanding of the initial host immune response to these viruses could provide insight into how to limit infection. Mouse retroviruses that are endemic in their hosts provide an important genetic tool to dissect the different arms of the innate immune system that recognize retroviruses as foreign. Here, we review what is known about the major branches of the innate immune system that respond to mouse retrovirus infection, Toll-like receptors and nucleic acid sensors, and discuss the importance of these responses in activating adaptive immunity and controlling infection.
Topics: Animals; Host Microbial Interactions; Immunity, Innate; Mice; Retroviridae; Retroviridae Infections; Virus Replication
PubMed: 32751803
DOI: 10.3390/v12080836 -
Viruses Jan 2021Within the family of , foamy viruses (FVs) are unique and unconventional with respect to many aspects in their molecular biology, including assembly and release of... (Review)
Review
Within the family of , foamy viruses (FVs) are unique and unconventional with respect to many aspects in their molecular biology, including assembly and release of enveloped viral particles. Both components of the minimal assembly and release machinery, Gag and Env, display significant differences in their molecular structures and functions compared to the other retroviruses. This led to the placement of FVs into a separate subfamily, the . Here, we describe the molecular differences in FV Gag and Env, as well as Pol, which is translated as a separate protein and not in an orthoretroviral manner as a Gag-Pol fusion protein. This feature further complicates FV assembly since a specialized Pol encapsidation strategy via a tripartite Gag-genome-Pol complex is used. We try to relate the different features and specific interaction patterns of the FV Gag, Pol, and Env proteins in order to develop a comprehensive and dynamic picture of particle assembly and release, but also other features that are indirectly affected. Since FVs are at the root of the retrovirus tree, we aim at dissecting the unique/specialized features from those shared among the and Such analyses may shed light on the evolution and characteristics of virus envelopment since related viruses within the , for instance LTR retrotransposons, are characterized by different levels of envelopment, thus affecting the capacity for intercellular transmission.
Topics: Capsid; Genome, Viral; Host-Pathogen Interactions; Humans; Retroviridae Infections; Spumavirus; Viral Proteins; Virus Assembly; Virus Physiological Phenomena; Virus Release; Virus Replication
PubMed: 33451128
DOI: 10.3390/v13010105 -
Viruses Oct 2020Apolipoprotein B mRNA editing enzyme, catalytic peptide 3 (APOBEC3) proteins are critical host proteins that counteract and prevent the replication of retroviruses.... (Review)
Review
Apolipoprotein B mRNA editing enzyme, catalytic peptide 3 (APOBEC3) proteins are critical host proteins that counteract and prevent the replication of retroviruses. Unlike the genome of humans and other species, the mouse genome encodes a single gene, which has undergone positive selection, as reflected by the allelic variants found in different inbred mouse strains. This positive selection was likely due to infection by various mouse retroviruses, which have persisted in their hosts for millions of years. While mouse retroviruses are inhibited by APOBEC3, they nonetheless still remain infectious, likely due to the actions of different viral proteins that counteract this host factor. The study of viruses in their natural hosts provides important insight into their co-evolution.
Topics: Animals; Cytidine Deaminase; Host-Pathogen Interactions; Leukemia Virus, Murine; Mammary Tumor Virus, Mouse; Mice; Retroviridae; Retroviridae Infections; Tumor Virus Infections; Virus Replication
PubMed: 33121095
DOI: 10.3390/v12111217