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Developments in Biological... 1992This overview summarizes the properties and mechanism of retroviral DNA integration and the consequences of the integration process to the infected cell and host.... (Review)
Review
This overview summarizes the properties and mechanism of retroviral DNA integration and the consequences of the integration process to the infected cell and host. Integration of viral into cellular DNA is a regular and irreversible event, essential for virus replication, whose mechanism is becoming well understood. Many pathogenic consequences of retrovirus infection are due to side-effects of the integration process, including gene disruption, activation of proto-oncogenes, acquisition of oncogenes, and inappropriate expression of viral gene products. The properties and risks associated with these events are reviewed along with overall conclusions as to the importance of these to possible retroviral contaminants of biologicals.
Topics: Animals; DNA, Viral; Gene Expression Regulation, Viral; Proto-Oncogenes; Retroviridae; Virus Integration; Virus Replication
PubMed: 1478335
DOI: No ID Found -
Nature Medicine Jan 2003
Review
Topics: Adenoviridae; Animals; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors; Humans; Ligands; Retroviridae
PubMed: 12514727
DOI: 10.1038/nm0103-135 -
BioMed Research International 2013Gene delivery vectors based on retroviral or lentiviral particles are considered powerful tools for biomedicine and biotechnology applications. Such vectors require... (Review)
Review
Gene delivery vectors based on retroviral or lentiviral particles are considered powerful tools for biomedicine and biotechnology applications. Such vectors require modification at the genomic level in the form of rearrangements to allow introduction of desired genes and regulatory elements (genotypic modification) as well as engineering of the physical virus particle (phenotypic modification) in order to mediate efficient and safe delivery of the genetic information to the target cell nucleus. Phenotypic modifications are typically introduced at the genomic level through genetic manipulation of the virus producing cells. However, this paper focuses on methods which allow modification of viral particle surfaces after they have exited the cell, that is, directly on the viral particles in suspension. These methods fall into three categories: (i) direct covalent chemical modification, (ii) membrane-topic reagents, and (iii) adaptor systems. Current applications of such techniques will be introduced and their advantages and disadvantages will be discussed.
Topics: Genetic Engineering; Genetic Vectors; Lentivirus; Retroviridae; Surface Properties; Virion
PubMed: 23691494
DOI: 10.1155/2013/253521 -
AIDS (London, England) 1989
Review
Topics: Animals; Cat Diseases; Cats; Immunologic Deficiency Syndromes; Retroviridae; Retroviridae Infections
PubMed: 2558688
DOI: 10.1097/00002030-198901001-00006 -
Immunological Reviews Aug 1996Endogenous retroviruses (ERVs) are estimated to comprise up to 1% of human DNA. While the genome of many ERVs is interrupted by termination codons, deletions or frame... (Review)
Review
Endogenous retroviruses (ERVs) are estimated to comprise up to 1% of human DNA. While the genome of many ERVs is interrupted by termination codons, deletions or frame shift mutations, some ERVs are transcriptionally active and recent studies reveal protein expression or particle formation by human ERVs. ERVs have been implicated as aetiological agents of autoimmune disease, because of their structural and sequence similarities to exogenous retroviruses associated with immune dysregulation and their tissue-specific or differentiation-dependent expression. In fact, retrovirus-like particles distinct from those of known exogenous retroviruses and immune responses to ERV proteins have been observed in autoimmune disease. Quantitatively or structurally aberrant expression of normally cryptic ERVs, induced by environmental or endogenous factors, could initiate autoimmunity through direct or indirect mechanisms. ERVs may lead to immune dysregulation as insertional mutagens or cis-regulatory elements of cellular genes involved in immune function. ERVs may also encode elements like tax in human T-lymphotrophic virus type I (HTLV-I) or tat in human immunodeficiency virus-I (HIV-I) that are capable of transactivating cellular genes. More directly, human ERV gene products themselves may be immunologically active, by analogy with the superantigen activity in the long terminal repeat (LTR) of mouse mammary tumour viruses (MMTV) and the non-specific immunosuppressive activity in mammalian type C retrovirus env protein. Alternatively, increased expression of an ERV protein, or expression of a novel ERV protein not expressed in the thymus during acquisition of immune tolerance, may lead to its perception as a neoantigen. Paraneoplastic syndromes raise the possibility that novel ERV-encoded epitopes expressed by a tumour elicit immunity to cross-reactive epitopes in normal tissues. Recombination events between different but related ERVs, to whose products the host is immunologically tolerant, may also generate new antigenic determinants. Frequently reported humoral immunity to exogenous retrovirus proteins in autoimmune disease could be elicited by cross-reactive ERV proteins. A review of the evidence implicating ERVs in immune dysfunction leads to the conclusion that direct molecular studies are likely to establish a pathogenic role for ERVs in autoimmune disease.
Topics: Animals; Autoimmunity; Gene Expression Regulation, Viral; Humans; Retroviridae
PubMed: 8930674
DOI: 10.1111/j.1600-065x.1996.tb00917.x -
Uirusu 2016The first terrestrial vertebrates emerged from water and adapted to living on land approximately 360 million years ago (late Devonian). In particular, amphibians are... (Review)
Review
The first terrestrial vertebrates emerged from water and adapted to living on land approximately 360 million years ago (late Devonian). In particular, amphibians are thought to have surface epithelia that changed from multilayered epithelia into keratinized stratified squamous epithelia by acquiring stratum corneum (SC), which is composed of several dead cell layers that serve as an air liquid interface barrier. Then, reptiles appeared and became a major terrestrial vertebrate group approximately 340 million years ago by forming hard SC. About 220 million years ago, mammals radiated by acquiring soft and moisturized SC, and endogenous retroviruses were thought to be actively integrated into mammalian genomes. Skin ASpartic Protease (SASPase)/ASPRV1 is the mammalian-specific endogenous retroviral-derived protease. SASPase-deficient mice had dry skin and aberrant accumulation of profilaggrin, which is another mammalian-specific gene that regulates SC barrier function and is a major predisposing factor for atopic dermatitis. These findings indicate that the retroviral element SASPase was integrated into the first mammalian species and was involved in the adaptive evolution of mammals, as it facilitates moisturization of skin SC. It is possible that other uncharacterized endogenous retroviruses were also involved in epidermal barrier function.
Topics: Adaptation, Biological; Animals; Aspartic Acid Proteases; Biological Evolution; Genome; Humans; Retroviridae; Skin; Skin Physiological Phenomena; Vertebrates
PubMed: 28484176
DOI: 10.2222/jsv.66.31 -
Seminars in Cancer Biology Jun 2009
Topics: Animals; DNA Methylation; Epigenesis, Genetic; Gene Silencing; Humans; Neoplasms; Retroviridae
PubMed: 19429475
DOI: 10.1016/j.semcancer.2009.02.014 -
Current Protein & Peptide Science Dec 2001Several retroviruses, including equine infectious anemia virus (EIAV), visna virus, caprine arthritis-encephalitis virus (CAEV) and feline immunodeficiency virus (FIV)... (Review)
Review
Several retroviruses, including equine infectious anemia virus (EIAV), visna virus, caprine arthritis-encephalitis virus (CAEV) and feline immunodeficiency virus (FIV) encode dUTPase. The role of this enzyme in the replication of these viruses has been scrutinized, with particular emphasis on potential roles for dUTPase in virulence and viral mutation rate. Overall, the results of these studies have indicated a central role for dUTPase in facilitating productive viral replication in non-dividing cells. The requirement for dUTPase in EIAV, which replicates exclusively in macrophages, may be the most stringent. Studies of dUTPase mutants of virulent EIAV clones suggest that the enzyme is a major determinant of virulence. In contrast, FIV readily replicates in dividing cell populations such as CD4+ and CD8+ T cells, and B cells as well as in non-dividing macrophages. Thus, the virus burden and disease sequelae are lowered in cats infected with a dUTPase-minus FIV relative to cats infected with wild type FIV, but not totally abrogated. Growth in macrophages is attenuated with the DU-minus FIV with evidence of a 5 to 8-fold increase in G-->A transition mutations in viral integrants present in macrophages. These findings are consistent with an increase in uracil misincorporation in the absence of dUTPase, resulting in transition mutations that cripple the virus. Effects on virus replication and disease production have also been noted for dUTPase-deleted CEAV and visna virus. While HIV and SIV do not encode dUTPase some reports suggest that other viral and host cell factors may substitute for its activity. Betaretroviruses also encode dUTPase and while several of these cause significant disease, the role of dUTPase in their replication and pathogenesis is currently unknown.
Topics: Gene Deletion; Mutation; Pyrophosphatases; Retroviridae; Virulence; Virus Replication
PubMed: 12374097
DOI: 10.2174/1389203013381008 -
Oncogene Sep 2005HTLV-1 was discovered in the US in 1979, and published in 1980. This was rapidly followed by four additional reports in early 1981 describing additional isolates,... (Review)
Review
HTLV-1 was discovered in the US in 1979, and published in 1980. This was rapidly followed by four additional reports in early 1981 describing additional isolates, characterization of some of the HTLV-1 proteins, serological assays for specific antibodies indicative of HTLV-1 infection, and evidence for integrated DNA proviruses in infected cells. None of this early work was dependent upon or influenced by the subclassification of some T-cell malignancies as ATL (in Japan). Instead, I was stimulated by prior work from many investigators in the US and Europe on retroviruses which caused leukemia in animals and our discoveries were made possible by our technical approaches developed in the 1970s involving especially sensitive assays for RT as a surrogate marker for a retrovirus and our discovery of Il-2 which made it possible to culture human T cells. However, following our reports the same virus was isolated in Japan, and both groups provided evidence that HTLV-1 caused ATL, a subclassification of T-cell malignancies first recognized in Japan.
Topics: Animals; HTLV-I Infections; Human T-lymphotropic virus 1; Human T-lymphotropic virus 2; Humans; Leukemia, T-Cell; Retroviridae
PubMed: 16155599
DOI: 10.1038/sj.onc.1208980 -
Methods in Molecular Biology (Clifton,... 2004
Review
Topics: Animals; Cells, Cultured; Gene Transfer Techniques; Genetic Engineering; Genetic Vectors; HIV-1; Humans; Lentivirus; Moloney murine leukemia virus; Retroviridae; Transduction, Genetic; Transfection
PubMed: 15269408
DOI: 10.1385/1-59259-822-6:141