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Genome Analysis and Replication Studies of the African Green Monkey Simian Foamy Virus Serotype 3 Strain FV2014. Viruses 2020; 12:v12040403. [PMID: 32268512 PMCID: PMC7232438 DOI: 10.3390/v12040403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/27/2020] [Accepted: 04/01/2020] [Indexed: 01/23/2023] Open
Abstract
African green monkey (AGM) spumaretroviruses have been less well-studied than other simian foamy viruses (SFVs). We report the biological and genomic characterization of SFVcae_FV2014, which was the first foamy virus isolated from an African green monkey (AGM) and was found to be serotype 3. Infectivity studies in various cell lines from different species (mouse, dog, rhesus monkey, AGM, and human) indicated that like other SFVs, SFVcae_FV2014 had broad species and cell tropism, and in vitro cell culture infection resulted in cytopathic effect (CPE). In Mus dunni (a wild mouse fibroblast cell line), MDCK (Madin-Darby canine kidney cell line), FRhK-4 (a fetal rhesus kidney cell line), and MRC-5 (a human fetal lung cell line), SFVcae_FV2014 infection was productive resulting in CPE, and had delayed or similar replication kinetics compared with SFVmcy_FV21 and SFVmcy_FV34[RF], which are two Taiwanese macaque isolates, designated as serotypes 1 and 2, respectively. However, in Vero (AGM kidney cell line) and A549 (a human lung carcinoma cell line), the replication kinetics of SFVcae_FV2014 and the SFVmcy viruses were discordant: In Vero, SFVcae_FV2014 showed rapid replication kinetics and extensive CPE, and a persistent infection was seen in A549, with delayed, low CPE, which did not progress even upon extended culture (day 55). Nucleotide sequence analysis of the assembled SFVcae_FV2014 genome, obtained by high-throughput sequencing, indicated an overall 80–90% nucleotide sequence identity with SFVcae_LK3, the only available full-length genome sequence of an AGM SFV, and was distinct phylogenetically from other AGM spumaretroviruses, corroborating previous results based on analysis of partial env sequences. Our study confirmed that SFVcae_FV2014 and SFVcae_LK3 are genetically distinct AGM foamy virus (FV) isolates. Furthermore, comparative infectivity studies of SFVcae_FV2014 and SFVmcy isolates showed that although SFVs have a wide host range and cell tropism, regulation of virus replication is complex and depends on the virus strain and cell-specific factors.
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2
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Murata H, Yamada A, Babasaki K. Identification of repetitive sequences containing motifs of retrotransposons in the ectomycorrhizal basidiomycete Tricholoma matsutake. Mycologia 2019. [DOI: 10.1080/00275514.1999.12061082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Hitoshi Murata
- Division of Bio-Resource Development, Forestry and Forest Products Research Institute, P.O. Box 16, Tsukuba-Norin, 305-8687, Japan
| | - Akiyoshi Yamada
- Ibaraki Prefectural Forestry Center, Naka-machi, To 4692, Ibaraki 311-0122 Japan
| | - Katsuhiko Babasaki
- Division of Bio-Resource Development, Forestry and Forest Products Research Institute, P.O. Box 16, Tsukuba-Norin, 305-8687, Japan
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3
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Khan AS, Bodem J, Buseyne F, Gessain A, Johnson W, Kuhn JH, Kuzmak J, Lindemann D, Linial ML, Löchelt M, Materniak-Kornas M, Soares MA, Switzer WM. Spumaretroviruses: Updated taxonomy and nomenclature. Virology 2018; 516:158-164. [PMID: 29407373 PMCID: PMC11318574 DOI: 10.1016/j.virol.2017.12.035] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 12/29/2017] [Accepted: 12/29/2017] [Indexed: 01/28/2023]
Abstract
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.
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Affiliation(s)
- Arifa S Khan
- Laboratory of Retroviruses, US Food and Drug Administration, Silver Spring, MD 20993, USA.
| | - Jochen Bodem
- Institut für Virologie und Immunbiologie, Universität Würzburg, Würzburg, Germany
| | - Florence Buseyne
- Unit of Epidemiology and Physiopathology of Oncogenic Viruses, Institut Pasteur, Paris, France; Centre National de la Recherche Scientifique, CNRS UMR3569, Paris, France
| | - Antoine Gessain
- Unit of Epidemiology and Physiopathology of Oncogenic Viruses, Institut Pasteur, Paris, France; Centre National de la Recherche Scientifique, CNRS UMR3569, Paris, France
| | - Welkin Johnson
- Biology Department, Boston College, Chestnut Hill, MA 02467, USA
| | - Jens H Kuhn
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, USA
| | - Jacek Kuzmak
- Department of Biochemistry, National Veterinary Research Institute, Puławy, Poland
| | - Dirk Lindemann
- Institute of Virology, Technische Universität Dresden, Dresden, Germany
| | - Maxine L Linial
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Martin Löchelt
- Research Program Infection, Inflammation and Cancer, German Cancer Research Center (DFKZ), Heidelberg, Germany
| | | | - Marcelo A Soares
- Instituto Nacional de Câncer and Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - William M Switzer
- Laboratory Branch, Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
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4
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Complete Genome Sequence of the African Green Monkey Simian Foamy Virus Serotype 3 Strain FV2014 (SFVcae_FV2014). GENOME ANNOUNCEMENTS 2018; 6:6/3/e01437-17. [PMID: 29348335 PMCID: PMC5773720 DOI: 10.1128/genomea.01437-17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The full-length sequence of simian foamy virus serotype 3 (SFV-3) strain FV2014, an African green monkey (Chlorocebus aethiops) isolate, was obtained using high-throughput sequencing. SFVcae_FV2014 consisted of 13,127 bp and had a genomic organization similar to those of other SFVs but was distinct from SFV strain LK3, isolated from the same monkey species.
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5
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Abstract
Recent discoveries indicate that the foamy virus (FV) (Spumavirus) ancestor may have been among the first retroviruses to appear during the evolution of vertebrates, demonstrated by foamy endogenous retroviruses present within deeply divergent hosts including mammals, coelacanth, and ray-finned fish. If they indeed existed in ancient marine environments hundreds of millions of years ago, significant undiscovered diversity of foamy-like endogenous retroviruses might be present in fish genomes. By screening published genomes and by applying PCR-based assays of preserved tissues, we discovered 23 novel foamy-like elements in teleost hosts. These viruses form a robust, reciprocally monophyletic sister clade with sarcopterygian host FV, with class III mammal endogenous retroviruses being the sister group to both clades. Some of these foamy-like retroviruses have larger genomes than any known retrovirus, exogenous or endogenous, due to unusually long gag-like genes and numerous accessory genes. The presence of genetic features conserved between mammalian FV and these novel retroviruses attests to a foamy-like replication biology conserved for hundreds of millions of years. We estimate that some of these viruses integrated recently into host genomes; exogenous forms of these viruses may still circulate.
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Affiliation(s)
- Ryan Ruboyianes
- Department of Ecology and Evolutionary Biology, University of Arizona, 1041 E Lowell St., Tucson, AZ 85721, USA
| | - Michael Worobey
- Department of Ecology and Evolutionary Biology, University of Arizona, 1041 E Lowell St., Tucson, AZ 85721, USA
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Katzourakis A, Aiewsakun P, Jia H, Wolfe ND, LeBreton M, Yoder AD, Switzer WM. Discovery of prosimian and afrotherian foamy viruses and potential cross species transmissions amidst stable and ancient mammalian co-evolution. Retrovirology 2014; 11:61. [PMID: 25091111 PMCID: PMC4261875 DOI: 10.1186/1742-4690-11-61] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 07/02/2014] [Indexed: 02/06/2023] Open
Abstract
Background Foamy viruses (FVs) are a unique subfamily of retroviruses that are widely distributed in mammals. Owing to the availability of sequences from diverse mammals coupled with their pattern of codivergence with their hosts, FVs have one of the best-understood viral evolutionary histories ever documented, estimated to have an ancient origin. Nonetheless, our knowledge of some parts of FV evolution, notably that of prosimian and afrotherian FVs, is far from complete due to the lack of sequence data. Results Here, we report the complete genome of the first extant prosimian FV (PSFV) isolated from a lorisiforme galago (PSFVgal), and a novel partial endogenous viral element with high sequence similarity to FVs, present in the afrotherian Cape golden mole genome (ChrEFV). We also further characterize a previously discovered endogenous PSFV present in the aye-aye genome (PSFVaye). Using phylogenetic methods and available FV sequence data, we show a deep divergence and stable co-evolution of FVs in eutherian mammals over 100 million years. Nonetheless, we found that the evolutionary histories of bat, aye-aye, and New World monkey FVs conflict with the evolutionary histories of their hosts. By combining sequence analysis and biogeographical knowledge, we propose explanations for these mismatches in FV-host evolutionary history. Conclusion Our discovery of ChrEFV has expanded the FV host range to cover the whole eutherian clade, and our evolutionary analyses suggest a stable mammalian FV-host co-speciation pattern which extends as deep as the exafroplacentalian basal diversification. Nonetheless, two possible cases of host switching were observed. One was among New World monkey FVs, and the other involves PSFVaye and a bat FV which may involve cross-species transmission at the level of mammalian orders. Our results highlight the value of integrating multiple sources of information to elucidate the evolutionary history of viruses, including continental and geographical histories, ancestral host locations, in addition to the natural history of host and virus. Electronic supplementary material The online version of this article (doi:10.1186/1742-4690-11-61) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Aris Katzourakis
- Department of Zoology, University of Oxford, Oxford, South Parks Road, Oxford OX1 3PS, UK.
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Kehl T, Tan J, Materniak M. Non-simian foamy viruses: molecular virology, tropism and prevalence and zoonotic/interspecies transmission. Viruses 2013; 5:2169-209. [PMID: 24064793 PMCID: PMC3798896 DOI: 10.3390/v5092169] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 09/04/2013] [Accepted: 09/05/2013] [Indexed: 12/27/2022] Open
Abstract
Within the field of retrovirus, our knowledge of foamy viruses (FV) is still limited. Their unique replication strategy and mechanism of viral persistency needs further research to gain understanding of the virus-host interactions, especially in the light of the recent findings suggesting their ancient origin and long co-evolution with their nonhuman hosts. Unquestionably, the most studied member is the primate/prototype foamy virus (PFV) which was originally isolated from a human (designated as human foamy virus, HFV), but later identified as chimpanzee origin; phylogenetic analysis clearly places it among other Old World primates. Additionally, the study of non-simian animal FVs can contribute to a deeper understanding of FV-host interactions and development of other animal models. The review aims at highlighting areas of special interest regarding the structure, biology, virus-host interactions and interspecies transmission potential of primate as well as non-primate foamy viruses for gaining new insights into FV biology.
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Affiliation(s)
- Timo Kehl
- German Cancer Research Center, INF242, Heidelberg 69120, Germany
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +49-6221-42-4935; Fax: +49-6221-42-4932
| | - Juan Tan
- College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China; E-Mail:
| | - Magdalena Materniak
- Department of Biochemistry, National Veterinary Research Institute, Partyzantow Ave. 57, Pulawy 24-100, Poland; E-Mail:
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Schrom EM, Moschall R, Hartl MJ, Weitner H, Fecher D, Langemeier J, Bohne J, Wöhrl BM, Bodem J. U1snRNP-mediated suppression of polyadenylation in conjunction with the RNA structure controls poly (A) site selection in foamy viruses. Retrovirology 2013; 10:55. [PMID: 23718736 PMCID: PMC3694450 DOI: 10.1186/1742-4690-10-55] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 05/21/2013] [Indexed: 11/13/2022] Open
Abstract
Background During reverse transcription, retroviruses duplicate the long terminal repeats (LTRs). These identical LTRs carry both promoter regions and functional polyadenylation sites. To express full-length transcripts, retroviruses have to suppress polyadenylation in the 5′LTR and activate polyadenylation in the 3′LTR. Foamy viruses have a unique LTR structure with respect to the location of the major splice donor (MSD), which is located upstream of the polyadenylation signal. Results Here, we describe the mechanisms of foamy viruses regulating polyadenylation. We show that binding of the U1 small nuclear ribonucleoprotein (U1snRNP) to the MSD suppresses polyadenylation at the 5′LTR. In contrast, polyadenylation at the 3′LTR is achieved by adoption of a different RNA structure at the MSD region, which blocks U1snRNP binding and furthers RNA cleavage and subsequent polyadenylation. Conclusion Recently, it was shown that U1snRNP is able to suppress the usage of intronic cryptic polyadenylation sites in the cellular genome. Foamy viruses take advantage of this surveillance mechanism to suppress premature polyadenylation at the 5’end of their RNA. At the 3’end, Foamy viruses use a secondary structure to presumably block access of U1snRNP and thereby activate polyadenylation at the end of the genome. Our data reveal a contribution of U1snRNP to cellular polyadenylation site selection and to the regulation of gene expression.
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Affiliation(s)
- Eva-Maria Schrom
- Institute of Virology and Immunobiology, University of Würzburg, Würzburg, Germany
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9
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Identification of recombination in the envelope gene of simian foamy virus serotype 2 isolated from Macaca cyclopis. J Virol 2013; 87:8792-7. [PMID: 23698303 DOI: 10.1128/jvi.03555-12] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The full-length sequence of simian foamy virus serotype 2 (SFVmcy-2), isolated from a Taiwanese macaque, was determined. SFVmcy-2 was highly related to SFV serotype 1 (SFVmcy-1), an isolate from the same species, except in the putative receptor binding domain (RBD) in env, which contained novel sequences related to SFV serotype 3 (SFVagm-3), isolated from an African green monkey. The results identify a potential region of neutralization in SFVs and demonstrate recombination between genetically divergent foamy viruses.
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10
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Abstract
Foamy viruses (FVs) are distinct members of the retrovirus (RV) family. In this chapter, the molecular regulation of foamy viral transcription, splicing, polyadenylation, and RNA export will be compared in detail to the orthoretroviruses. Foamy viral transcription is regulated in early and late phases, which are separated by the usage of two promoters. The viral transactivator protein Tas activates both promoters. The nature of this early-late switch and the molecular mechanism used by Tas are unique among RVs. RVs duplicate the long terminal repeats (LTRs) during reverse transcription. These LTRs carry both a promoter region and functional poly(A) sites. In order to express full-length transcripts, RVs have to silence the poly(A) signal in the 5' LTR and to activate it in the 3' LTR. FVs have a unique R-region within these LTRs with a major splice donor (MSD) at +51 followed by a poly(A) signal. FVs use a MSD-dependent mechanism to inactivate the polyadenylation. Most RVs express all their genes from a single primary transcript. In order to allow expression of more than one gene from this RNA, differential splicing is extensively used in complex RVs. The splicing pattern of FV is highly complex. In contrast to orthoretroviruses, FVs synthesize the Pol precursor protein from a specific and spliced transcript. The LTR and IP-derived primary transcripts are spliced into more than 15 different mRNA species. Since the RNA ratios have to be balanced, a tight regulation of splicing is required. Cellular quality control mechanisms retain and degrade unspliced or partially spliced RNAs in the nucleus. In this review, I compare the RNA export pathways used by orthoretroviruses with the distinct RNA export pathway used by FV. All these steps are highly regulated by host and viral factors and set FVs apart from all other RVs.
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Affiliation(s)
- Jochen Bodem
- Institute of Virology and Immunobiology, University of Würzburg, Würzburg, Germany
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11
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Schulze A, Lemey P, Schubert J, McClure MO, Rethwilm A, Bodem J. Complete nucleotide sequence and evolutionary analysis of a gorilla foamy virus. J Gen Virol 2010; 92:582-6. [PMID: 21106805 DOI: 10.1099/vir.0.027011-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To shed light on primate foamy virus (FV) evolution, we determined the complete nucleotide sequence of the gorilla simian foamy virus (SFVgor). Starting from a conserved region in the integrase (IN) domain of the pol gene we cloned the viral genome to the 5' and 3' LTR into plasmid vectors and elucidated its nucleotide sequence. The sequences of both LTRs were determined by nucleotide sequencing of separate PCR products from the primer-binding site or the bel region and LTRs. All protein motifs conserved among the primate FV were identified in SFVgor. Using phylogenetic analysis of the Gag, Pol and Env amino acid sequences, we demonstrate that SFVgor consistently clusters in accordance with a scenario of virus-host co-divergence.
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Affiliation(s)
- Andrea Schulze
- Institute of Virology and Immunobiology, University of Würzburg, Germany
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12
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Tan J, Hao P, Jia R, Yang W, Liu R, Wang J, Xi Z, Geng Y, Qiao W. Identification and functional characterization of BTas transactivator as a DNA-binding protein. Virology 2010; 405:408-13. [PMID: 20615521 DOI: 10.1016/j.virol.2010.05.037] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 05/26/2010] [Accepted: 05/28/2010] [Indexed: 11/15/2022]
Abstract
The genome of bovine foamy virus (BFV) encodes a transcriptional transactivator, namely BTas, that remarkably enhances gene expression by binding to the viral long-terminal repeat promoter (LTR) and internal promoter (IP). In this report, we characterized the functional domains of BFV BTas. BTas contains two major functional domains: the N-terminal DNA-binding domain (residues 1-133) and the C-terminal activation domain (residues 198-249). The complete BTas responsive regions were mapped to the positions -380/-140 of LTR and 9205/9276 of IP. Four BTas responsive elements were identified at the positions -368/-346, -327/-307, -306/-285 and -186/-165 of the BFV LTR, and one element was identified at the position 9243/9264 of the BFV IP. Unlike other foamy viruses, the five BTas responsive elements in BFV shared obvious sequence homology. These data suggest that among the complex retroviruses, BFV appears to have a unique transactivation mechanism.
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Affiliation(s)
- Juan Tan
- State Key Laboratory of Elemento-Organic Chemistry and Department of Chemical Biology, Nankai University, Tianjin 300071, China
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13
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Chang YF, Wang SM, Huang KJ, Wang CT. Mutations in capsid major homology region affect assembly and membrane affinity of HIV-1 Gag. J Mol Biol 2007; 370:585-97. [PMID: 17532005 DOI: 10.1016/j.jmb.2007.05.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Revised: 04/30/2007] [Accepted: 05/03/2007] [Indexed: 11/22/2022]
Abstract
We introduced mutations into the HIV-1 major homology region (MHR; capsids 153-172) and adjacent C-terminal region to analyze their effects on virus-like particle (VLP) assembly, membrane affinity, and the multimerization of the Gag structural protein. Results indicate that alanine substitutions at K158, F168 or E175 significantly diminished VLP production. All assembly-defective Gag mutants had markedly reduced membrane-binding capacities, but results from a velocity sedimentation analysis suggest that most of the membrane-bound Gag proteins were present, primarily in a higher-order multimerized form. The membrane-binding capacity of the K158A, F168A, and E175A Gag proteins increased sharply upon removal of the MA globular domain. While demonstrating improved multimerization capability, the two MA-deleted versions of F168A and E175A did not show marked improvement in VLP production, presumably due to a defect in association with the raft-like membrane domain. However, K158A bound to detergent-resistant raft-like membrane; this was accompanied by noticeably improved VLP production following MA removal. Our results suggest that the HIV-1 MHR and adjacent downstream region facilitate multimerization and tight Gag packing. Enhanced Gag multimerization may help expose the membrane-binding domain and thus improve Gag membrane binding, thereby promoting Gag multimerization into higher-order assembly products.
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Affiliation(s)
- Yu-Fen Chang
- Institute of Public Health, National Yang-Ming University School of Medicine, Taipei, Taiwan
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14
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Jones-Engel L, Engel GA, Schillaci MA, Rompis A, Putra A, Suaryana KG, Fuentes A, Beer B, Hicks S, White R, Wilson B, Allan JS. Primate-to-human retroviral transmission in Asia. Emerg Infect Dis 2005; 11:1028-35. [PMID: 16022776 PMCID: PMC3371821 DOI: 10.3201/eid1107.040957] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We describe the first reported transmission to a human of simian foamy virus (SFV) from a free-ranging population of nonhuman primates in Asia. The transmission of an exogenous retrovirus, SFV, from macaques (Macaca fascicularis) to a human at a monkey temple in Bali, Indonesia, was investigated with molecular and serologic techniques. Antibodies to SFV were detected by Western blotting of serum from 1 of 82 humans tested. SFV DNA was detected by nested polymerase chain reaction (PCR) from the blood of the same person. Cloning and sequencing of PCR products confirmed the virus's close phylogenetic relationship to SFV isolated from macaques at the same temple. This study raises concerns that persons who work at or live around monkey temples are at risk for infection with SFV.
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Affiliation(s)
- Lisa Jones-Engel
- University of Washington National Primate Research Center, Seattle, Washington 98195, USA.
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15
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Russell RA, Wiegand HL, Moore MD, Schäfer A, McClure MO, Cullen BR. Foamy virus Bet proteins function as novel inhibitors of the APOBEC3 family of innate antiretroviral defense factors. J Virol 2005; 79:8724-31. [PMID: 15994766 PMCID: PMC1168746 DOI: 10.1128/jvi.79.14.8724-8731.2005] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Foamy viruses are a family of complex retroviruses that establish common, productive infections in a wide range of nonhuman primates. In contrast, humans appear nonpermissive for foamy virus replication, although zoonotic infections do occur. Here we have analyzed the ability of primate and mouse APOBEC3G proteins to inhibit the infectivity of primate foamy virus (PFV) virions produced in their presence. We demonstrate that several APOBEC3 proteins can potently inhibit the infectivity of a PFV-based viral vector. This inhibition correlated with the packaging of inhibitory APOBEC3 proteins into PFV virions, due to a specific PFV Gag/APOBEC3 interaction, and resulted in the G to A hypermutation of PFV reverse transcripts. While inhibition of PFV virion infectivity by primate APOBEC3 proteins was largely relieved by coexpression of the PFV Bet protein, a cytoplasmic auxiliary protein of previously uncertain function, Bet failed to relieve inhibition caused by murine APOBEC3. PFV Bet bound to human, but not mouse, APOBEC3 proteins in coexpressing cells, and this binding correlated with the specific inhibition of their incorporation into PFV virions. Of note, both PFV Bet and a second Bet protein, derived from an African green monkey foamy virus, rescued the infectivity of Vif-deficient human immunodeficiency virus type 1 (HIV-1) virions produced in the presence of African green monkey APOBEC3G and blocked the incorporation of this host factor into HIV-1 virion particles. However, neither foamy virus Bet protein reduced APOBEC3 protein expression levels in virion producer cells. While these data identify the foamy virus Bet protein as a functional ortholog of the HIV-1 Vif auxiliary protein, they also indicate that Vif and Bet block APOBEC3 protein function by distinct mechanisms.
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Affiliation(s)
- Rebecca A Russell
- Jefferiss Trust Laboratories, Wright-Fleming Institute, Imperial College, London, United Kingdom
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16
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Verschoor EJ, Langenhuijzen S, van den Engel S, Niphuis H, Warren KS, Heeney JL. Structural and evolutionary analysis of an orangutan foamy virus. J Virol 2003; 77:8584-7. [PMID: 12857929 PMCID: PMC165240 DOI: 10.1128/jvi.77.15.8584-8587.2003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2003] [Accepted: 04/30/2003] [Indexed: 11/20/2022] Open
Abstract
The full-length proviral genome of a foamy virus infecting a Bornean orangutan was amplified, and its sequence was analyzed. Although the genome showed a clear resemblance to other published foamy virus genomes from apes and monkeys, phylogenetic analysis revealed that simian foamy virus SFVora was evolutionarily equidistant from foamy viruses from other hominoids and from those from Old World monkeys. This finding suggests an independent evolution within its host over a long period of time.
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Affiliation(s)
- Ernst J Verschoor
- Department of Virology, Biomedical Primate Research Centre, Rijswijk, The Netherlands.
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17
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Teysset L, Dang VD, Kim MK, Levin HL. A long terminal repeat-containing retrotransposon of Schizosaccharomyces pombe expresses a Gag-like protein that assembles into virus-like particles which mediate reverse transcription. J Virol 2003; 77:5451-63. [PMID: 12692246 PMCID: PMC153967 DOI: 10.1128/jvi.77.9.5451-5463.2003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Tf1 element of Schizosaccharomyces pombe is a long terminal repeat-containing retrotransposon that encodes functional protease, reverse transcriptase, and integrase proteins. Although these proteins are known to be necessary for protein processing, reverse transcription, and integration, respectively, the function of the protein thought to be Gag has not been determined. We present here the first electron microscopy of Tf1 particles. We tested whether the putative Gag of Tf1 was required for particle formation, packaging of RNA, and reverse transcription. We generated deletions of 10 amino acids in each of the four hydrophilic domains of the protein and found that all four mutations reduced transposition activity. The N-terminal deletion removed a nuclear localization signal and inhibited nuclear import of the transposon. The two mutations in the center of Gag destabilized the protein and resulted in no virus-like particles. The C-terminal deletion caused a defect in RNA packaging and, as a result, low levels of cDNA. The electron microscopy of cells expressing a truncated Tf1 showed that Gag alone was sufficient for the formation of virus-like particles. Taken together, these results indicate that Tf1 encodes a Gag protein that is a functional equivalent of the Gag proteins of retroviruses.
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Affiliation(s)
- Laure Teysset
- Section on Eukaryotic Transposable Elements, Laboratory of Gene Regulation and Development, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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18
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Blewett EL, Black DH, Lerche NW, White G, Eberle R. Simian foamy virus infections in a baboon breeding colony. Virology 2000; 278:183-93. [PMID: 11112493 DOI: 10.1006/viro.2000.0649] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The prevalence, transmission, and variation of simian foamy viruses (SFVs) in baboons was investigated. Over 95% of adult baboons in the breeding colony as well as recently imported adult animals had high titers of anti-SFV serum IgG. Maternal antibody was detectable in infants' serum up to 6 months of age. Approximately 30% of infants in breeding harems experienced SFV infections by 1 year of age. Shedding of SFV in oral secretions was common, with 13% of samples from normal adult animals and 35% from immunosuppressed animals containing infectious SFV. SFV was isolated from three baboon subspecies (olive, yellow, and chacma baboons) and sequences from both the pol and the LTR regions of the provirus were amplified by PCR and sequenced. Phylogenetic analysis indicated that all baboon isolates formed a single lineage distinct from SFVs of other African monkey species. Within the baboon SFV lineage, two distinct clades were apparent, which consisted of isolates from yellow and olive baboons and isolates from chacma baboons. Competition ELISAs indicated that, while SFV isolates of these two groups were very closely related, antigenic differences do exist between them. SFV isolates from a drill and a mandrill were distinct from baboon SFV isolates, both genetically and antigenically.
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Affiliation(s)
- E L Blewett
- College of Osteopathic Medicine, Tulsa, Oklahoma 74107, USA
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19
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Abstract
The sequence within the 5' untranslated region of the retroviral genome contains important cis elements for many steps in viral replication. There is limited information available on the role of this region in foamy virus replication. Similar to other retroviruses, the 5' untranslated region of foamy viruses predicts extensive RNA secondary structure. Serial mutations that could change parts of the predicted secondary structure were introduced in the 5' leader sequence including the R-U5 region of simian foamy virus type 1 (SFV-1) to investigate their role in virus genome packaging and virus replication. Point mutations in the R-U5 regions at nucleotide positions 7-12 (I), 241-243 (B), and 256-257 (D) had no effect on virus replication. Base substitution mutation at positions 193-195 (C), however, severely impaired virus replication. Deletion of sequences in the leader region, between the primer-binding site and the gag gene, at positions 364-399 (d1), 397-435 (d2), or 364-435 (d3), which included sequences for RNA genome dimerization, also blocked SFV-1 replication. Interestingly, none of these mutations affected genome packaging or the synthesis of viral transcripts, suggesting that a step(s) of virus replication following packaging is affected. The region between the primer-binding site and the gag gene, therefore, is not essential for foamy virus genome packaging. Furthermore, the cis-acting elements for genome dimerization and packaging appear to be localized in separate regions for foamy viruses.
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Affiliation(s)
- J Park
- Department of Pathobiology, College of Veterinary Medicine, University of Florida, Gainesville, Florida 32610, USA
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20
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Schweizer M, Schleer H, Pietrek M, Liegibel J, Falcone V, Neumann-Haefelin D. Genetic stability of foamy viruses: long-term study in an African green monkey population. J Virol 1999; 73:9256-65. [PMID: 10516034 PMCID: PMC112960 DOI: 10.1128/jvi.73.11.9256-9265.1999] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genetic variability of the envelope surface domain (SU) of simian foamy virus (FV) of African green monkeys was studied. To assess the interindividual diversity of FV, isolates were obtained from 19 animals living together in a monkey house. The monkeys had been imported from Kenya prior to being placed in long-term housing in the research institute. In addition, a simian FV isolate and proviral DNA were obtained from an animal caretaker infected in this setting. DNA of the complete SU (1779 to 1793 bp) was analyzed by PCR and sequencing. The sequences revealed four clusters with high homologies (>95%). Between the clusters, divergencies ranged from 3 to 25%. Obviously, the clusters reflect four different strains or subtypes of simian FV type 3 that were prevalent in the colony. In contrast to lentiviruses, hypervariable regions could not be detected in the FV SU. Furthermore, to analyze the intraindividual diversity of FV, we investigated the virus population within an individual monkey at a given time point and its evolution over 13 years. For this purpose, 22 proviral SU clones generated by PCR from one oral swab and seven isolates obtained from the same animal between 1982 and 1995 were examined. These sequences revealed exceptionally high homology rates (99.5 to 100%), and only a minimal genetic drift was recognized within the series of isolates. In conclusion, the low in vivo divergency of FV SU suggests that genetic variability is not important for the maintenance of FV persistence.
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Affiliation(s)
- M Schweizer
- Abteilung Virologie, Institut für Medizinische Mikrobiologie und Hygiene, University of Freiburg, Freiburg, Germany.
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21
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Callahan ME, Switzer WM, Matthews AL, Roberts BD, Heneine W, Folks TM, Sandstrom PA. Persistent zoonotic infection of a human with simian foamy virus in the absence of an intact orf-2 accessory gene. J Virol 1999; 73:9619-24. [PMID: 10516073 PMCID: PMC112999 DOI: 10.1128/jvi.73.11.9619-9624.1999] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although foamy viruses (FVs) are endemic among nonhuman primates, FV infection among humans is rare. Recently, simian foamy virus (SFV) infection was reported in 4 of 231 individuals occupationally exposed to primates (1.8%). Secondary transmission to spouses has not been seen, suggesting that while FV is readily zoonotic, humans may represent dead-end hosts. Among different simian species, SFV demonstrates significant sequence diversity within the U3 region of the long terminal repeat (LTR) and 3' accessory open reading frames (ORFs). To examine if persistent human SFV infection and apparent lack of secondary transmission are associated with genetic adaptations in FV regulatory regions, we conducted sequence analysis of the LTR, internal promoter, ORF-1, and ORF-2 on a tissue culture isolate and peripheral blood mononuclear cell samples from a human infected with SFV of African green monkey origin (SFV-3). Compared to the prototype SFV-3 sequence, the LTR, internal promoter, and FV transactivator (ORF-1) showed sequence conservation, suggesting that FV zoonosis is not dependent on host-specific adaptation to these transcriptionally important regions. However, ORF-2 contains a number of deleterious mutations predicted to result in premature termination of protein synthesis. ORF-2 codes in part for the 60-kDa Bet fusion protein, proposed to be involved in the establishment of persistent cellular SFV infections. These results suggest that persistent human infection by SFV and reduced transmissibility may be influenced by the absence of a functional ORF-2.
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Affiliation(s)
- M E Callahan
- HIV/AIDS Branch, Division of AIDS, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA
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22
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Khan AS, Sears JF, Muller J, Galvin TA, Shahabuddin M. Sensitive assays for isolation and detection of simian foamy retroviruses. J Clin Microbiol 1999; 37:2678-86. [PMID: 10405421 PMCID: PMC85313 DOI: 10.1128/jcm.37.8.2678-2686.1999] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/1998] [Accepted: 04/26/1999] [Indexed: 11/20/2022] Open
Abstract
Simian foamy viruses (SFVs) are highly prevalent in a variety of nonhuman primate species ranging from prosimians to apes. SFVs possess a broad host range, and human infections can occur by cross-species transfer (W. Heneine et al., Nat. Med. 4:403-407, 1998). Retrovirus screening of potential sources of infection, such as laboratory research animals and simian-derived biological products, could minimize human exposure to SFVs by reducing the risk of potential retrovirus infection in humans. We describe a variety of sensitive assays for SFV isolation and detection which were developed with a prototype strain of SFV serotype 2. The Mus dunni cell line (M. R. Lander and S. K. Chattopadhyay, J. Virol. 52:695-698, 1984) was found to be highly sensitive for SFV production on the basis of various general and specific retrovirus detection assays such as reverse transcriptase assay, transmission electron microscopy, immunofluorescence assay, and Western blotting. A highly sensitive PCR assay was developed on the basis of the sequences in primary SFV isolates obtained from pig-tailed macaques (Macaca nemestrina) and rhesus macaques (Macaca mulatta). Analysis of naturally occurring SFV infection in macaques indicated that analysis by a combination of assays, including both highly sensitive, specific assays and less sensitive, broadly reactive assays, is important for evaluation of retrovirus infection.
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Affiliation(s)
- A S Khan
- Laboratory of Retrovirus Research, Division of Viral Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Bethesda, Maryland 20892, USA.
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23
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Falcone V, Leupold J, Clotten J, Urbanyi E, Herchenröder O, Spatz W, Volk B, Böhm N, Toniolo A, Neumann-Haefelin D, Schweizer M. Sites of simian foamy virus persistence in naturally infected African green monkeys: latent provirus is ubiquitous, whereas viral replication is restricted to the oral mucosa. Virology 1999; 257:7-14. [PMID: 10208915 DOI: 10.1006/viro.1999.9634] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Foamy viruses (FV), retroviruses of the genus Spumavirus, are able to infect a wide variety of animal species and replicate in nearly all types of cultured cells. To identify the cells targeted by FV in the natural host and define the sites of viral replication, multiple organs of four African green monkeys naturally infected with simian FV type 3 were investigated for the presence of FV proviral DNA and viral transcripts. All organs contained significant amounts of FV proviral DNA. In addition to proviruses containing the complete transactivator gene taf, proviral genomes carrying a specific 295-bp deletion in the taf gene were detected in all monkeys. As in the case of human foamy virus the deletion leads to the formation of the bet gene that is regarded to be instrumental in the regulation of viral persistence. FV RNA was detected by RT-PCR and in situ hybridization only in the oral mucosa of one monkey. No other samples contained detectable levels of viral transcripts. Histopathological changes were not observed in any of the tissue samples analyzed. Our results show that the natural history of FV is characterized by latent infection in all organs of the host and by minimal levels of harmless viral replication in the oral mucosa. The broad host cell range in vivo further encourages the development of FV-derived vectors for therapeutic gene delivery.
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Affiliation(s)
- V Falcone
- Institute for Medical Microbiology and Hygiene, University of Freiburg, Freiburg, Germany
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24
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Winkler IG, Flügel RM, Löchelt M, Flower RL. Detection and molecular characterisation of feline foamy virus serotypes in naturally infected cats. Virology 1998; 247:144-51. [PMID: 9705907 DOI: 10.1006/viro.1998.9232] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The characterisation of two distinct feline foamy virus sequence groupings in the external surface portion of the viral env gene are reported. Although amino acid identities in the Gag nucleocapsid, Pol protease, and Env transmembrane domains were greater than 92% in the 12 proviral sequences examined, two distinct sequence groups were observed in the Env surface (SU) protein. Only 57% amino acid identity was observed in the Env SU between the two groups designated FUV7-like or 951-like, while within these groups > 97% identity was found. Isolates FUV7 and 951 represent two serogroups previously characterised by Flower et al. (1985). A 100% correlation was found among FeFV seroreactivity, virus isolation, and detection of viral DNA in feline leucocytes using a single round of PCR amplification. Serum neutralisation assay using autologous virus, as well as isolates 951 and FUV7, revealed that viruses with FUV7-like sequences were in a single neutralisation group and viruses with 951-like sequences were in a single neutralisation group. Based on these results, group-specific PCRs were developed, using the same sense primer with an antisense primer specific for each group. Using he PCR, no evidence of superinfection of any cat with virus from both serogroups was detected.
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Affiliation(s)
- I G Winkler
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia
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25
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Wu M, Chari S, Yanchis T, Mergia A. cis-Acting sequences required for simian foamy virus type 1 vectors. J Virol 1998; 72:3451-4. [PMID: 9525680 PMCID: PMC109851 DOI: 10.1128/jvi.72.4.3451-3454.1998] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/1997] [Accepted: 12/06/1997] [Indexed: 02/06/2023] Open
Abstract
We have constructed a series of vectors based on simian foamy virus type 1 (SFV-1) to define the minimum cis-acting elements required for gene transfer. To characterize these vectors, we inserted the coding sequence of the bacterial lacZ gene linked to the cytomegalovirus immediate-early gene promoter. Introduction of a deletion mutation in the leader region between the 5' long terminal repeat and the start of the gag gene at position 1659 to 1694 completely abrogated gene transfer by the SFV-1 vector. Deletion of 39 nucleotides from position 1692 to 1731 in the leader region resulted in a significant reduction in the transducing-particle titer. Furthermore, we have identified a second cis-acting element located at the 3' end of the pol gene between position 6486 and 6975 to be critical for SFV-1 vector transduction. These results identify the two important cis-acting elements required for SFV-1 vector construction, and the finding of a cis-acting element in the pol gene is unique among retroviruses.
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Affiliation(s)
- M Wu
- Department of Pathobiology, College of Veterinary Medicine, University of Florida, Gainesville 32610, USA
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26
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Holzschu DL, Delaney MA, Renshaw RW, Casey JW. The nucleotide sequence and spliced pol mRNA levels of the nonprimate spumavirus bovine foamy virus. J Virol 1998; 72:2177-82. [PMID: 9499074 PMCID: PMC109513 DOI: 10.1128/jvi.72.3.2177-2182.1998] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We have determined the complete nucleotide sequence of a replication-competent clone of bovine foamy virus (BFV) and have quantitated the amount of splice pol mRNA processed early in infection. The 544-amino-acid Gag protein precursor has little sequence similarity with its primate foamy virus homologs, but the putative nucleocapsid (NC) protein, like the primate NCs, contains the three glycine-arginine-rich regions that are postulated to bind genomic RNA during virion assembly. The BFV gag and pol open reading frames overlap, with pro and pol in the same translational frame. As with the human foamy virus (HFV) and feline foamy virus, we have detected a spliced pol mRNA by PCR. Quantitatively, this mRNA approximates the level of full-length genomic RNA early in infection. The integrase (IN) domain of reverse transcriptase does not contain the canonical HH-CC zinc finger motif present in all characterized retroviral INs, but it does contain a nearby histidine residue that could conceivably participate as a member of the zinc finger. The env gene encodes a protein that is over 40% identical in sequence to the HFV Env. By comparison, the Gag precursor of BFV is predicted to be only 28% identical to the HFV protein.
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Affiliation(s)
- D L Holzschu
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
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27
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Abstract
We have cloned proviral DNA of simian foamy virus type 1 (SFV-1) from linear unintegrated DNA (pSFV-1). Transfection of pSFV-1 induces cytopathology in several cell lines with supernatants from the transfected cell culture containing infectious viral particles. Electron microscopy of the transfected cells revealed foamy virus particles. Deletion analysis of pSFV-1 indicated that the transcriptional transactivator (tas) gene located between env and the long terminal repeat is critical for virus replication, whereas the second open reading frame (ORF-2) in this region is dispensable. Although the tas and ORF-2 regions of foamy viruses have significantly diverged, the results presented here suggested that the gene products have similar functions. Recombinant pSFV-1 containing the cat gene was able to transduce the heterologous gene, indicating the utility of SFV-1 as a vector. An infectious clone of SFV-1 which is distantly related to the human foamy virus will provide a means to understand the biology of this unique group of viruses.
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Affiliation(s)
- A Mergia
- Department of Pathobiology, College of Veterinary Medicine, University of Florida, Gainesville 32610, USA.
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28
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Winkler I, Bodem J, Haas L, Zemba M, Delius H, Flower R, Flügel RM, Löchelt M. Characterization of the genome of feline foamy virus and its proteins shows distinct features different from those of primate spumaviruses. J Virol 1997; 71:6727-41. [PMID: 9261397 PMCID: PMC191953 DOI: 10.1128/jvi.71.9.6727-6741.1997] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The genome of the feline foamy virus (FeFV) isolate FUV was characterized by molecular cloning and nucleotide sequence analysis of subgenomic proviral DNA. The overall genetic organization of FeFV and protein sequence comparisons of different FeFV genes with their counterparts from other known foamy viruses confirm that FeFV is a complex foamy virus. However, significant differences exist when FeFV is compared with primate foamy viruses. The FeFV Gag protein is smaller than that of the primate spumaviruses, mainly due to additional MA/CA sequences characteristic of the primate viruses only. Gag protein sequence motifs of the NC domain of primate foamy viruses assumed to be involved in genome encapsidation are not conserved in FeFV. FeFV Gag and Pol proteins were detected with monospecific antisera directed against Gag and Pol domains of the human foamy virus and with antisera from naturally infected cats. Proteolytic processing of the FeFV Gag precursor was incomplete, whereas more efficient proteolytic cleavage of the pre125Pro-Pol protein was observed. The active center of the FeFV protease contains a Gln that replaces an invariant Gly residue at this position in other retroviral proteases. Functional studies on FeFV gene expression directed by the promoter of the long terminal repeat showed that FeFV gene expression was strongly activated by the Bell/Tas transactivator protein. The FeFV Bell/Tas transactivator is about one-third smaller than its counterpart of primate spumaviruses. This difference is also reflected by a limited sequence similarity and only a moderate conservation of structural motifs of the different foamy virus transactivators analyzed.
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Affiliation(s)
- I Winkler
- Abteilung Retrovirale Genexpression, Forschungsschwerpunkt Angewandte Tumorvirologie, Deutsches Krebsforschungszentrum, Heidelberg, Germany
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29
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Pfrepper KI, Löchelt M, Schnölzer M, Flügel RM. Expression and molecular characterization of an enzymatically active recombinant human spumaretrovirus protease. Biochem Biophys Res Commun 1997; 237:548-53. [PMID: 9299401 DOI: 10.1006/bbrc.1997.7187] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The human foamy virus (HFV) protease (PR) was cloned into a modified thioredoxin fusion vector that carried a His-tag in the centrally located surface loop of the E. coli trxA protein, bacterially expressed as a soluble fusion protein, and subsequently purified by affinity chromatography. By using HFV Gag protein substrates, the purified recombinant HFV PR was enzymatically active whereas the corresponding active site PR mutant Asp/Ala was inactive. Incubation of synthetic peptides containing residues that flank the putative cleavage site with the recombinant HFV PR and subsequent matrix-assisted laser desorption ionization mass spectrometry of the cleavage products identified the proteolytic processing site of the HFV Gag precursor p74 and revealed that the peptide sequence RAVNTVTQ was cleaved between the Asn and Thr bond.
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Affiliation(s)
- K I Pfrepper
- Abteilung Retrovirale Genexpression, Deutsches Krebsforschungszentrum, Heidelberg, Germany
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30
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Bieniasz PD, Erlwein O, Aguzzi A, Rethwilm A, McClure MO. Gene transfer using replication-defective human foamy virus vectors. Virology 1997; 235:65-72. [PMID: 9300037 DOI: 10.1006/viro.1997.8658] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Replication-defective vectors based on an infectious molecular clone of human foamy virus (HFV) were constructed by deletion and replacement of the accessory genes with expression cassettes for puromycin-resistance and beta-glucouronidase. Cell lines which produced in excess of 10(5) helper virus-free transducing units/ml were generated by trans-complementation of the replication defect using a BHK-21-derived cell line expressing the Bel-1 transactivator. Vectors based on the HFV genome may provide useful alternatives to existing retroviral vectors.
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Affiliation(s)
- P D Bieniasz
- Department of G. U. Medicine and Communicable Diseases, Imperial College School of Medicine at St. Mary's, Paddington, London, United Kingdom
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31
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Schmidt M, Herchenröder O, Heeney J, Rethwilm A. Long terminal repeat U3 length polymorphism of human foamy virus. Virology 1997; 230:167-78. [PMID: 9143272 DOI: 10.1006/viro.1997.8463] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Size determination of the long terminal repeat (LTR) of an early (1985) and a more recent (1993) passage of wild-type human foamy virus (HFV) revealed that the virus has undergone substantial deletions in the U3 region upon replication in tissue culture. Two LTR deletion variants (HSRV1 and 2) have been characterized in the past and used to construct molecular clones which are replication competent in cell culture. We now report the molecular cloning, sequencing, and biological characterization of an HFV genome with full-length LTR (pHFV2). Sequence analysis revealed that the deletions in HSRV1 and 2 are nonrandom and probably occurred by misalignment during reverse transcription. The comparative analysis of HFV2 and the variant with the largest U3 deletion, HSRV2, revealed a differential ability to replicate in human cell cultures. While HSRV2 replicated faster in diploid human fibroblasts, cells which have been used extensively for amplification of HFV in the past, replication of HFV2 was faster in a lymphoblastoid cell line. Reporter gene assays indicated that the cell-type specific ability of the LTRs to respond to the viral transcriptional transactivator may be a likely, reason for the different growth properties of both viruses and for the occurrence of the HFV U3 deletions. In foamy virus-infected chimpanzees only the full-length type of LTR was observed; however, the HSRV1 deletion variant was detected as the dominating virus in an accidentally HFV-infected human.
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Affiliation(s)
- M Schmidt
- Institut für Virologie und Immunbiologie, Würzburg, Germany
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32
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Erlwein O, Cain D, Fischer N, Rethwilm A, McClure MO. Identification of sites that act together to direct dimerization of human foamy virus RNA in vitro. Virology 1997; 229:251-8. [PMID: 9123868 DOI: 10.1006/viro.1997.8438] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Retroviral particles contain two molecules of genomic RNA, which are noncovalently linked near their 5' ends in a region called the dimer linkage structure (DLS). By using complementary DNA oligonucleotides and deletion mutants to impair RNA dimerization of the human foamy virus (HFV), three sites, designated SI, SII, and SIII, were found within a 159-nucleotide RNA fragment of HFV that are involved in dimerization in vitro. SI overlaps the primer-binding site; and SII contains the palindromic sequence, UCCCUAGGGA, the disruption of which impairs dimer formation; and SIII extends into the gag gene. The first two sites are highly conserved in the other primate foamy viruses, SFV-1, SFV-3, and SFVcpz, whereas the third appears to be shared only by HFV and SFVcpz. RNA of HFV and SFV-3 could form heterodimers, indicating that both viruses dimerize by similar mechanisms. On testing thermal stability, dimers of the 159-nucleotide fragment dissociated between 40 and 70 degrees, with half of the dimers dissociating at 55 degrees. Since the splice donor site of HFV is located at position 51 of viral RNA, the DLS is part of the genomic RNA exclusively.
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Affiliation(s)
- O Erlwein
- Department of Genito-Urinary Medicine & Communicable Diseases, Jefferiss Research Trust Laboratories, Imperial College School of Medicine at St. Mary's, London, United Kingdom
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33
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Martin J, Herniou E, Cook J, Waugh O'Neill R, Tristem M. Human endogenous retrovirus type I-related viruses have an apparently widespread distribution within vertebrates. J Virol 1997; 71:437-43. [PMID: 8985368 PMCID: PMC191069 DOI: 10.1128/jvi.71.1.437-443.1997] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Retroviruses from lower vertebrate hosts have been poorly characterized to date. Few sequences have been isolated, and those which have been reported are all highly divergent when compared to the retroviruses known to be harbored by mammals and birds. Here we show that retroviruses with significant homology to the human endogenous retrovirus type I (HERV-I) are present within the genomes of fish, reptiles, birds, and mammals and that they may well be widespread within many vertebrates. Phylogenetic analysis of nucleotide sequences strongly supported the inclusion of viruses from each of these vertebrate classes into one monophyletic group. This analysis also demonstrated that the HERV-I-related viruses are more closely related to retroviruses belonging to the murine leukemia virus genus than to members of the other retroviral genera. The presence of HERV-I-related retroviruses in so many disparate vertebrate hosts suggests that other endogenous human retroviruses may also have a much wider distribution than is currently appreciated.
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Affiliation(s)
- J Martin
- Department of Biology, Imperial College, Ascot, Berkshire, United Kingdom
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Goepfert PA, Shaw KL, Ritter GD, Mulligan MJ. A sorting motif localizes the foamy virus glycoprotein to the endoplasmic reticulum. J Virol 1997; 71:778-84. [PMID: 8985416 PMCID: PMC191117 DOI: 10.1128/jvi.71.1.778-784.1997] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We recently identified an endoplasmic reticulum (ER) retrieval signal-the dilysine motif-in the glycoproteins of all five foamy viruses (FVs) for which sequences were available (P. A. Goepfert, G. Wang, and M. J. Mulligan, Cell 82:543-544, 1995). In the present study, expression of recombinant human FV (HFV) glycoprotein and analyses of oligosaccharide modifications and precursor cleavage indicated that the protein was localized to the ER. HFV glycoproteins encoding seven different dilysine motif mutations were then expressed. The results indicated that disruptions of the dilysine motif resulted in higher levels of forward transport of the HFV glycoprotein from the ER through the Golgi apparatus to the plasma membrane. We conclude that the dilysine motif is responsible for ER sorting of the FV glycoprotein. Signal-mediated ER localization has not previously been described for a retroviral glycoprotein.
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Affiliation(s)
- P A Goepfert
- Department of Medicine, University of Alabama at Birmingham, 35294-2170, USA
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35
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Bodem J, Löchelt M, Winkler I, Flower RP, Delius H, Flügel RM. Characterization of the spliced pol transcript of feline foamy virus: the splice acceptor site of the pol transcript is located in gag of foamy viruses. J Virol 1996; 70:9024-7. [PMID: 8971036 PMCID: PMC191004 DOI: 10.1128/jvi.70.12.9024-9027.1996] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Foamy viruses, or spumaviruses, are distinct members of the Retroviridae. Here we have characterized the long terminal repeat of the feline, or cat, foamy virus by determining the locations of the transcriptional start site and the poly(A) addition site. The splice donor and splice acceptor sites of the subgenomic mRNA responsible for Pro-Pol protein expression were identified by nucleotide sequencing of the corresponding cDNAs. The leader exon of the feline foamy virus is 57 nucleotides long. The splice acceptor of the subgenomic pol mRNA was found to be located in gag. The location of the splice acceptor of the human foamy virus pol mRNA was confirmed to map in gag. The pol splice acceptor site in gag of the cat foamy virus is located further downstream than that of human foamy virus.
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Affiliation(s)
- J Bodem
- Abteilung Retrovirale Genexpression, Forschungsschwerpunkt Angewandte Tumorvirologie, Deutsches Krebsforschungszentrum, Heidelberg, Germany
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36
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Tristem M, Herniou E, Summers K, Cook J. Three retroviral sequences in amphibians are distinct from those in mammals and birds. J Virol 1996; 70:4864-70. [PMID: 8676524 PMCID: PMC190434 DOI: 10.1128/jvi.70.7.4864-4870.1996] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We isolated and characterized three endogenous retroviral fragments from the dart-poison frog Dendrobates ventrimaculatus. These are the first retroviral sequences to be identified in amphibians, and consequently retroviruses have now been found in each of the five major vertebrate classes. Comparison of the amphibian retroviral fragments, termed DevI, DevII, and DevIII, with mammalian and avian isolates revealed significant differences between their nucleotide sequences. This suggested that they were only distantly related to the seven currently recognized retroviral genera. Additional analysis by phylogeny reconstruction showed that the amphibian retroviral fragments were approximately equally related to the Moloney leukemia-related viruses, the spumaviruses, and walleye dermal sarcoma virus. Hybridization experiments revealed that viruses closely related to DevI, DevII, and DevIII do not appear to be widespread in other vertebrates and that DevI, DevII, and DevIII are all present at high copy numbers within their amphibian hosts, typically at over 250 copies per genome. The viruses described here, along with two others which have recently been found in a fish and a reptile, indicate that there may be some major differences in the retroviruses harbored by different vertebrate classes. This suggests that further characterization of retroviruses of fish, reptiles, and amphibians will help in understanding the evolution of the whole retroviral family and may well lead to the discovery of retroviruses with novel biological properties.
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Affiliation(s)
- M Tristem
- Department of Biology, Imperial College, Silwood Park, United Kingdom
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Enssle J, Jordan I, Mauer B, Rethwilm A. Foamy virus reverse transcriptase is expressed independently from the Gag protein. Proc Natl Acad Sci U S A 1996; 93:4137-41. [PMID: 8633029 PMCID: PMC39500 DOI: 10.1073/pnas.93.9.4137] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In the foamy virus (FV) subgroup of retroviruses the pol genes are located in the +1 reading frame relative to the gag genes and possess potential ATG initiation codons in their 5' regions. This genome organization suggests either a + 1 ribosomal frameshift to generate a Gag-Pol fusion protein, similar to all other retroviruses studied so far, or new initiation of Pol translation, as used by pararetroviruses, to express the Pol protein. By using a genetic approach we have ruled out the former possibility and provide evidence for the latter. Two down-mutations (M53 and M54) of the pol ATG codon were found to abolish replication and Pol protein expression of the human FV isolate. The introduction of a new ATG in mutation M55, 3' to the down-mutated ATG of mutation M53, restored replication competence, indicating that the pol ATG functions as a translational initiation codon. Two nonsense mutants (M56 and M57), which functionally separated gag and pol with respect to potential frame-shifting sites, were also replication-competent, providing further genetic evidence that FVs express the Pol protein independently from Gag. Our results show that during a particular step of the replication cycle, FVs differ fundamentally from all other retroviruses.
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Affiliation(s)
- J Enssle
- Institut für Virologie und Immunbiologie, Würzburg, Germany
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38
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Tobaly-Tapiero J, De Celis-Kosmas J, Bittoun P, Lasneret J, Poorters AM, Eladari ME, Emanoil-Ravier R. Isolation and characterization of infectious full-length DNA clones of chimpanzee foamy viruses SFV6 and SFV7: evidence for a Taf-dependent internal promoter. RESEARCH IN VIROLOGY 1996; 147:17-27. [PMID: 8882337 DOI: 10.1016/0923-2516(96)80236-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We have cloned complete viral genomes directly from Hirt supernatant DNAs of simian foamy virus types 6 and 7 (SFV6 and SFV7) -infected cells. These clones were shown to be infectious by transfection into cells and subsequent infection of susceptible cells either by cocultivation or by passage of cell-free supernatants. The presence of virus particles, suggested by a typical cytopathic effect, was confirmed by electron microscopy. These viruses were characterized at different levels of the replication cycle. The proviral genomes revealed a taf deletion comparable to that previously described in the human foamy virus (HFV) bel1 gene. Analysis of viral RNAs revealed similar patterns of transcripts for SFV6- and SFV7-infected cells, with predominant expression of accessory genes. Characteristic major viral polypeptides were identified by radioimmunoprecipitation for both isolates. Sequences homologous to the gene encoding Taf and to a potential internal promoter were identified in the infectious clones and subcloned into expression vectors. Their functional properties were tested by transfection assays, which provided evidence for the presence of a Taf-dependent internal promoter in both SFV6 and SFV7 isolates.
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Affiliation(s)
- J Tobaly-Tapiero
- UPR A0043, CNRS Rétrovirus et Rétrotransposons des Vertébrés, Hôpital Saint-Louis, Paris
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39
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Saïb A, de Thé H. Molecular biology of the human foamy virus. JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES AND HUMAN RETROVIROLOGY : OFFICIAL PUBLICATION OF THE INTERNATIONAL RETROVIROLOGY ASSOCIATION 1996; 13 Suppl 1:S254-60. [PMID: 8797732 DOI: 10.1097/00042560-199600001-00038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Foamy viruses also known as spumaretroviruses are complex retroviruses infecting cell lines with no apparent specific cellular tropism and induce the formation of multinucleated cells with numerous vacuoles. Far less well characterized than oncoviruses and lentiviruses, this class of viruses is thought to be innocuous in vivo. However, several important discoveries on foamy viruses brought new insights in the field of retrovirology.
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Affiliation(s)
- A Saïb
- CNRS UPR9051, Hôpital Saint-Louis, Paris, France
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Aguzzi A, Marino S, Tschopp R, Rethwilm A. Regulation of expression and pathogenic potential of human foamy virus in vitro and in transgenic mice. Curr Top Microbiol Immunol 1996; 206:243-73. [PMID: 8608720 DOI: 10.1007/978-3-642-85208-4_13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- A Aguzzi
- Department of Pathology, University of Zürich, Switzerland
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41
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Abstract
Several cell lines representing different species and cell types were tested for simian foamy virus type 1 (SFV-1) infection. SFV-1 infections were monitored by polymerase chain reaction, reverse transcriptase, cytopathology, and immunofluorescent assays. All cells tested were permissive for SFV-1, demonstrating that SFV-1 has a broad host range with respect to species and cell types. Infected fibroblasts, epithelial cells, and neural cells all showed extensive cytopathology that is characteristic of foamy virus infection. No cytopathology was induced in T cell-derived Jurkats and Hut-78 cell lines. The cytopathic effects in B and macrophage originated cells were delayed by several days. Cytopathology in these cell lines was not as dramatic as seen in the infected fibroblast and epithelial cells. The reverse transcriptase values in the SFV-1 infected lymphoid and macrophage cell lines were severalfold lower than that of the fibroblasts and epithelial cells. Therefore, SFV-1 appears to establish a low level persistent infection in lymphoid and macrophage cell lines.
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Affiliation(s)
- A Mergia
- Department of Pathobiology, College of Veterinary Medicine, University of Florida, Gainesville 32610, USA
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Tristem M, Kabat P, Herniou E, Karpas A, Hill F. Easel, a gypsy LTR-retrotransposon in the Salmonidae. MOLECULAR & GENERAL GENETICS : MGG 1995; 249:229-36. [PMID: 7500945 DOI: 10.1007/bf00290370] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Despite the close similarities between retroviruses and the gypsy/Ty3 group of LTR-retrotransposons their host ranges are largely distinct: the retroviruses are found only in vertebrates, whereas the gypsy LTR-retrotransposons are almost exclusively restricted to invertebrates, plants and fungi. Here we report the amplification by PCR, and characterisation, of one of the first LTR-retrotransposons to be discovered in vertebrates--in several members of the piscine family Salmonidae. Phylogenetic analysis of this retroelement, termed easel, indicates that it is probably a phylogeneticaly basal member of the gypsy group of LTR-retrotransposons and occurs in some of the same species from which retroviruses have previously been isolated. Thus some members of the Salmonidae are the first organisms known to harbour both retroviral branch elements and the gypsy LTR-retrotransposon branch elements. This creates an overlap in the host ranges of the two retroelement families.
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Affiliation(s)
- M Tristem
- Department of Biology, Imperial College, Ascot, Berkshire, UK
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43
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Cordonnier A, Casella JF, Heidmann T. Isolation of novel human endogenous retrovirus-like elements with foamy virus-related pol sequence. J Virol 1995; 69:5890-7. [PMID: 7543594 PMCID: PMC189468 DOI: 10.1128/jvi.69.9.5890-5897.1995] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
A new class of reverse transcriptase coding sequences was detected in reverse-transcribed RNAs from human placenta by polymerase chain amplification with primers in highly conserved regions of the pol gene of mammalian retroviruses and retrotransposons. Using one of these novel sequences as a probe to screen a human genomic library, we isolated retrovirus-like elements bordered by long terminal repeats and having a potential leucine tRNA primer-binding site. Determination of the complete nucleotide sequence (6,591 bp) of one of these elements, termed HERV-L (for human endogenous retrovirus with leucine tRNA primer), revealed domains of amino acid similarities to retroviral reverse transcriptase and integrase proteins. In addition, a region with homologies to dUTPase proteins was found unexpectedly downstream from the integrase domain. Amino acid sequence and phylogenetic analysis indicate that the HERV-L pol gene is related to that of foamy retroviruses. HERV-L-related sequences are detected in several mammalian species and have expanded in primate and mouse genomes up to 100 to 200 copies.
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Affiliation(s)
- A Cordonnier
- Unité de Physicochimie et Pharmacologie des Macromolécules Biologiques, Centre National de la Recherche Scientifique URA 147, Institut Gustave Roussy, Villejuif, France
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45
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Craven RC, Leure-duPree AE, Weldon RA, Wills JW. Genetic analysis of the major homology region of the Rous sarcoma virus Gag protein. J Virol 1995; 69:4213-27. [PMID: 7769681 PMCID: PMC189159 DOI: 10.1128/jvi.69.7.4213-4227.1995] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The mature cores of all retroviruses contain a major structural protein known as the CA (capsid) protein. Although it appears to form a shell around the ribonucleoprotein complex that contains the viral RNA, its function in viral replication is largely unknown. Little sequence similarity exists between the CA proteins of different retroviruses, except for a region of about 20 amino acids termed the major homology region (MHR). To examine the role of the CA protein in particle assembly and release, mutants of Rous sarcoma virus were created in which segments of CA were deleted or single conserved residues in the MHR were altered. The ability of the deletion mutants to release particles at rates similar to the wild-type protein demonstrated that the CA domain of Gag is not an essential component of the minimal budding machinery. Certain point mutations in the MHR region did block assembly and release in certain cell types, presumably by perturbing the global structure of the Gag precursor. Another group of MHR substitutions produced noninfectious or poorly infectious particles that were normal in their content of gag and pol gene products and viral RNA. The mutants were capable of initiating reverse transcription in vitro; however, the association of CA protein with the core was compromised, as indicated by its sensitivity to extraction with nonionic detergent. Prominent blebs on the virion envelope also indicated a disturbance at the membrane. Finally, an anti-peptide serum directed against MHR was found to react with the uncleaved Gag protein but not with mature CA, suggesting that MHR undergoes a dynamic rearrangement upon liberation from the polyprotein. We conclude that the MHR is involved in the very late steps in maturation of the virion (i.e., ones that occur after budding is initiated) and is essential for proper function of the core upon entry into a new host cell.
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Affiliation(s)
- R C Craven
- Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Hershey 17033, USA
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46
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Dias HW, Aboud M, Flügel RM. Analysis of the phylogenetic placement of different spumaretroviral genes reveals complex pattern of foamy virus evolution. Virus Genes 1995; 11:183-90. [PMID: 8828144 DOI: 10.1007/bf01728657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Foamy or spumaviruses are complex retroviruses. Phylogenetic trees have been constructed previously for either the polymerase or integrase domains showed a clustering of the foamy viruses relatively distant from other retroviruses. The most related retrovirus was found to be murine leukemia virus, irrespective of the method used or foamy viral gene analyzed. We analyze bel genes of different foamy viruses and compared the corresponding phylogenetic trees with those obtained from the pol genes that were constructed with refined computer programs. In addition, the nucleocapsid protein sequence of foamy viruses was used for a comparative phylogenetic analysis. Known biological properties of the individual FV protein domains are discussed to ascertain the apparent phylogenetic relatedness.
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Affiliation(s)
- H W Dias
- Abteilung Retroviral Genexpression, Forschungsschwerpunkt Angewandte Tumorvirologie, Heidelberg, Federal Republic of Germany
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47
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Schweizer M, Turek R, Hahn H, Schliephake A, Netzer KO, Eder G, Reinhardt M, Rethwilm A, Neumann-Haefelin D. Markers of foamy virus infections in monkeys, apes, and accidentally infected humans: appropriate testing fails to confirm suspected foamy virus prevalence in humans. AIDS Res Hum Retroviruses 1995; 11:161-70. [PMID: 7734189 DOI: 10.1089/aid.1995.11.161] [Citation(s) in RCA: 149] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Foamy viruses (FVs) persist in healthy individuals of various mammalian species, including nonhuman primates. Laboratory markers of FV infection are (1) virus in throat epithelium or peripheral blood lymphocytes (PBLs), (2) proviral DNA sequences in PBLs and various solid organs, and (3) antibodies reactive to viral antigens on Western blots, in radioimmunoprecipitation tests, and in immunofluorescence assays. Using PCR and serological tests, we readily detected FV markers in naturally infected African green monkeys, rhesus monkeys, and chimpanzees, as well as in accidentally infected humans. Transmission of simian foamy viruses to humans (by bite or inadvertent laboratory infection) leads to viral markers, without affecting the recipient. Reports on FV-associated clinical disorders (e.g., thyroid or neurological) have remained controversial. In this study we failed to detect, by PCR, viral sequences in the samples from 223 patients, including 16 HIV-infected Africans, 46 Graves' disease patients, and 28 patients with the de Quervain's thyroiditis. Evaluation of 2688 sera from suspected high-risk areas (e.g., Central and East Africa, or high-risk groups such as HIV-infected individuals and patients with AIDS, thyroid, and neurological disorders) did not reveal FV-specific antibodies in a single case. Previously reported FV seroprevalence in various populations has never been verified by appropriate confirmatory tests. The strain of "human foamy virus" has remained a unique isolate. In conclusion, FVs are unlikely--at present--to circulate in human populations.
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Affiliation(s)
- M Schweizer
- Abteilung Virologie, University of Freiburg, Germany
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48
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Affiliation(s)
- A Rethwilm
- Institute of Virology and Immunobiology, University of Würzburg, Germany
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49
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McClure MO, Bieniasz PD, Schulz TF, Chrystie IL, Simpson G, Aguzzi A, Hoad JG, Cunningham A, Kirkwood J, Weiss RA. Isolation of a new foamy retrovirus from orangutans. J Virol 1994; 68:7124-30. [PMID: 7933094 PMCID: PMC237151 DOI: 10.1128/jvi.68.11.7124-7130.1994] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have isolated a new foamy virus from blood samples taken from two apparently healthy orangutans (Pongo pygmaeus). The older orangutan has since died with encephalopathy after a brief acute illness, while the younger one, his grandson, remains well. These animals and 12 other orangutans had specific antibodies to foamy virus as measured by immunofluorescence. The new foamy virus and the antisera showed strong and specific neutralization, with only weak cross-reaction with other simian foamy virus strains. Southern blotting with gag and env probes of human foamy virus and PCR amplification showed that the new foamy virus, designated SFV-11, is related to, yet distinct from, previously characterized strains from humans, chimpanzees, and monkeys.
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Affiliation(s)
- M O McClure
- Department of Genitourinary Medicine and Communicable Diseases, Jefferiss Research Trust Laboratories, St. Mary's Hospital Medical School, London, United Kingdom
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50
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De Celis J, Tobaly-Tapiero J, Hampe A, Emanoil-Ravier R. Structure and function of the long terminal repeat of the chimpanzee foamy virus isolates (SFV-6). Arch Virol 1994; 138:345-55. [PMID: 7998839 DOI: 10.1007/bf01379137] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The complete long terminal repeat (LTR) nucleotide sequence of the chimpanzee foamy virus isolate SFV-6 was determined. Its 1761-bp size makes it the longest LTR reported to date among all retroviruses. Since the length of its LTR is similar to that of other simian isolates while its sequence homology is closer to that of HFV, SFV-6 genetic structure appears to be intermediate between simian and human foamy viruses. Transient expression assays demonstrate that SFV-6 encodes a transactivator of viral gene expression directed either by its own LTR or by heterologous promoters like HFV and HIV-1 LTRs. Our data also provide evidence for cross-transactivation between SFV-6 and HFV.
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Affiliation(s)
- J De Celis
- Laboratoire des Rétrovirus et Rétrotransposons des Vertébrés, UPR 0043 CNRS, Hopital Saint-Louis, Paris, France
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