Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| comparative sequence analysis and predictions for the envelope glycoproteins of foamy viruses. | the foamy viruses (fvs) are a genus of complex retroviruses that has recently been found to possess several novel molecular features. there is increasing interest in the development of fvs as novel vectors for gene delivery. as there are remarkably few published studies of fv proteins, these recent findings prompted us to predict the structural features of fv glycoproteins with the aid of computer programs. we analysed all seven available fv env sequences, a greater number of sequences than in p ... | 1999 | 9934708 |
| foamy viruses are unconventional retroviruses. | 1999 | 9971751 | |
| specific binding of recombinant foamy virus envelope protein to host cells correlates with susceptibility to infection. | the interaction of simian foamy viruses (fvs) with their putative cellular receptor(s) was studied with two types of recombinant envelope protein (env). transient expression of full-length env in bhk-21 cells induced syncytia formation. however, selected stable transfectants fused with naive cells but not with each other. a soluble fusion protein of the env surface domain with the fc fragment of a human igg1 heavy chain (envsu-ig) was produced in the baculovirus expression system, purified to ho ... | 1999 | 10069948 |
| feline viruses in wildcats from scotland. | few data are available on the prevalence of feline viruses in european wildcats (felis silvestris). previous surveys have indicated that wildcats may be infected with the common viruses of domestic cats, apart from feline immunodeficiency virus (fiv). in the present study, 50 wildcats trapped throughout scotland (uk) between august 1992 and january 1997 were tested for evidence of viral infection. all were negative for fiv by several serological or virological methods. by contrast, 10% of the ca ... | 1999 | 10073361 |
| foamy virus capsids require the cognate envelope protein for particle export. | unlike other subclasses of the retroviridae the spumavirinae, its prototype member being the so-called human foamy virus (hfv), require the expression of the envelope (env) glycoprotein for viral particle egress. both the murine leukemia virus (mulv) env and the vesicular stomatitis virus g protein, which efficiently pseudotype other retrovirus capsids, were not able to support export of hfv particles. analysis of deletion and point mutants of the hfv env protein revealed that the hfv env cytopl ... | 1999 | 10074106 |
| packaging cell lines for simian foamy virus type 1 vectors. | foamy viruses are nonpathogenic retroviruses that offer several unique opportunities for gene transfer in various cell types from different species. we have previously demonstrated the utility of simian foamy virus type 1 (sfv-1) as a vector system by transient expression assay (m. wu et al., j. virol. 72:3451-3454, 1998). in this report, we describe the first stable packaging cell lines for foamy virus vectors based on sfv-1. we developed two packaging cell lines in which the helper dna is plac ... | 1999 | 10196355 |
| detection of bovine retrospumavirus by the polymerase chain reaction. | a polymerase chain reaction (pcr) assay was developed for detection of bovine retrospumavirus (bovine syncytial virus; bsv) provirus dna. two different sets of oligonucleotide primers complementary to sequences located in the gag and the pol/env gene regions were used and compared for their ability to amplify the targeted bsv sequences by pcr. the results obtained from this study have shown that it is possible to amplify the bsv provirus dna sequences not only from total dna of bsv-infected cell ... | 1999 | 10204710 |
| 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. | 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 ... | 1999 | 10208915 |
| comparison of enzymatic activities of the hiv-1 and hfv integrases to their u5 ltr substrates. | the human immunodeficiency virus type 1 (hiv-1) and human foamy virus (hfv) integrase proteins were overexpressed in escherichia coli, and purified to a near homogeneity by one- or two-step purification scheme. the endonucleolytic, integration, and disintegration activities for the hiv-1 and hfv integrases were characterized in vitro. the endonucleolytic activities for the hiv-1 and hfv integrases were found only on their own substrates, respectively, indicating that the cognate u5 ltr sequences ... | 1999 | 10319414 |
| an active foamy virus integrase is required for virus replication. | foamy viruses (fvs) make use of a replication strategy which is unique among retroviruses and shows analogies to hepadnaviruses. the presence of an integrase (in) and obligate provirus integration distinguish retroviruses from hepadnaviruses. to clarify whether a functional in is required for fv replication, a mutant in the highly conserved dd35e motif of the active centre was analysed. this mutant was found to be able to express gag and pol protein precursors and cleavage products and to genera ... | 1999 | 10374962 |
| nuclear import of human immunodeficiency virus type-1 preintegration complexes. | following infection-mediated entry into the cytoplasm, retroviral cores form large nucleoprotein complexes (pics) which undergo reverse transcription and, ultimately, catalyze provirus formation. the ability of these complexes to be specifically imported into the nucleus via npcs explains why nondividing cells can be productively infected with lentiviruses such as hiv-1, whereas productive infection by the oncoretrovirus mlv is restricted to proliferating cells. current evidence suggests that vi ... | 1999 | 10384238 |
| proteolytic activity, the carboxy terminus of gag, and the primer binding site are not required for pol incorporation into foamy virus particles. | human foamy virus (hfv) is the prototype member of the spumaviruses. while similar in genomic organization to other complex retroviruses, foamy viruses share several features with their more distant relatives, the hepadnaviruses such as human hepatitis b virus (hbv). both hfv and hbv express their pol proteins independently from the structural proteins. however unlike hbv, pol is not required for assembly of hfv core particles or for packaging of viral rna. these results suggest that the assembl ... | 1999 | 10400731 |
| sensitive assays for isolation and detection of simian foamy retroviruses. | 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 ... | 1999 | 10405421 |
| replication of a foamy virus mutant with a constitutively active u3 promoter and deleted accessory genes. | foamy viruses (fvs) are complex retroviruses which require for their replication the activity of a transcriptional trans-activator (tas) as well as tas-responsive elements in the viral promoters. a mutant of the chimpanzee fv strain, cfv/hu (previously called human fv), genome in which most of the u3 promoter of the cfv long terminal repeat was substituted by the constitutively active human cytomegalovirus immediate early gene enhancer/promoter was constructed. this plasmid (pts12) and a derivat ... | 1999 | 10423126 |
| [the retroviral spumaviruses: new data in retrovirology]. | spumaviruses or foamy viruses belong to the retroviridae family. their genomic structure enables to classify them among the complex retroviruses like lentiviruses and the t leukemia viruses. these viruses, discovered 40 years ago, present a large cellular tropism and although highly lytic in vitro, they seem to be innocuous in vivo. however, recent fascinating findings on foamy viruses bring new important biological aspects of general interest for the field of retrovirology and show that these v ... | 1999 | 10437286 |
| an endoplasmic reticulum retrieval signal partitions human foamy virus maturation to intracytoplasmic membranes. | among all retroviruses, foamy viruses (fvs) are unique in that they regularly mature at intracytoplasmic membranes. the envelope glycoprotein of fv encodes an endoplasmic reticulum (er) retrieval signal, the dilysine motif (kkxx), that functions to localize the human fv (hfv) glycoprotein to the er. this study analyzed the function of the dilysine motif in the context of infectious molecular clones of hfv that encoded mutations in the dilysine motif. electron microscopy (em) demonstrated virion ... | 1999 | 10438808 |
| molecular characterization of proteolytic processing of the gag proteins of human spumavirus. | spumaviruses, or foamy viruses, express gag proteins that are incompletely processed by the viral protease in cell cultures. to delineate the proteolytic cleavage sites between potential gag subdomains, recombinant human spumaretrovirus (hsrv) gag proteins of different lengths were expressed, purified by affinity chromatography, and subjected to hsrv protease assays. hsrv-specific proteolytic cleavage products were isolated and characterized by western blotting. peptides spanning potential cleav ... | 1999 | 10438890 |
| epidemiology of feline foamy virus and feline immunodeficiency virus infections in domestic and feral cats: a seroepidemiological study. | although foamy viruses (spumaviruses) have repeatedly been isolated from both healthy and diseased cats, cattle, and primates, the primary mode of transmission of those common viruses remains undefined. a database of the feline foamy virus (fefv) and feline immunodeficiency virus (fiv) antibody status, age, and sex of 389 domestic cats presented to veterinarians was assembled. a similar database for 66 feral (wild) cats was also assembled. that fefv antibody status reflects infection was validat ... | 1999 | 10449463 |
| properties of human foamy virus relevant to its development as a vector for gene therapy. | the spumaviridae (foamy viruses) are increasingly being considered as potential vectors for gene therapy, yet little has been documented of their basic cell biology. this study demonstrates that human foamy virus (hfv) has a broad tropism and that the receptor for hfv is expressed not only on many mammalian, but on avian and reptilian cells. receptor interference assays using an envelope-expressing cell line and a vesicular stomatitis virus/hfv pseudotype virus demonstrate that the cellular rece ... | 1999 | 10466797 |
| genetic stability of foamy viruses: long-term study in an african green monkey population. | 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 ... | 1999 | 10516034 |
| persistent zoonotic infection of a human with simian foamy virus in the absence of an intact orf-2 accessory gene. | 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 ... | 1999 | 10516073 |
| endogenous virus of bhk-21 cells complicates electron microscopy studies of foamy virus maturation. | 1999 | 10523150 | |
| peripheral blood fibrocytes with foamy virus infection-like morphology. | 1999 | 10571524 | |
| human foamy virus genome in the thymus of myasthenia gravis patients. | the etiological relationship of human foamy virus (hfv), which is a spumaretrovirus, with human diseases is not clear. we analyzed thymus specimens from four patients with myasthenia gravis for the presence of hfv proviral genome by polymerase chain reaction (pcr). the results showed the presence of both 257 base pair (bp) and 299 bp dna fragments representing a part of gag and bel-2 sequences, respectively, in all four thymuses. their specificity was confirmed by southern blot hybridization wit ... | 1996 | 10592798 |
| serological and molecular diagnosis of bovine viral diarrhoea virus and evidence of other viral infections in dairy calves with respiratory disease in venezuela. | an investigation based on 2 studies was carried out to assess the involvement of bovine virus diarrhoea virus (bvdv), bovine herpesvirus type 1 (bhv-1), and bovine respiratory syncytial virus (brsv) in calf respiratory disease in dairy farms in venezuela. in the first study, 8 farms were selected and paired serum samples from 42 calves with respiratory disease were tested by elisa for antibodies to the 3 viruses. seroconversion to bvdv, bhv-1, and brsv was found to 5, 2, and 6 farms out of the 8 ... | 1999 | 10605142 |
| construction of infectious feline foamy virus genomes: cat antisera do not cross-neutralize feline foamy virus chimera with serotype-specific env sequences. | full-length genomes of the feline foamy virus (ffv or fefv) isolate fuv were constructed. dna clone pfefv-7 stably directed the expression of infectious ffv progeny virus indistinguishable from wild-type, uncloned ffv isolate fuv. the env and bel 1 genes of pfefv-7 were substituted for by corresponding sequences of the ffv serotype 951 since previous studies implicated a defined part of ffv env protein as responsible for serotype-specific differences in serum neutralization (i. g. winkler, r. m. ... | 2000 | 10612669 |
| multiple integrations of human foamy virus in persistently infected human erythroleukemia cells. | foamy viruses are complex retroviruses whose replication strategy resembles that of conventional retroviruses. however, foamy virus replication also resembles that of hepadnaviruses in many respects. because hepadnaviruses replicate in an integrase-independent manner, we were interested in investigating the characteristics of human foamy virus (hfv) integration. we have shown that hfv requires a functional integrase protein for infectivity. our analyses have revealed that in single-cell clones d ... | 2000 | 10644342 |
| simian foamy virus infection among zoo keepers. | we investigated 322 north american zoo workers in an anonymous serosurvey for antibodies to simian foamy viruses to establish the potential risk of zoonotic transmission by these retroviruses. 4 of 133 (3%) individuals who worked specifically with mammals including primates were seropositive, primarily with chimp-like viruses, indicating the importance of work practices to reduce exposure to these agents. | 2000 | 10683011 |
| the intact retroviral env glycoprotein of human foamy virus is a trimer. | electron microscopy of negatively stained human foamy virus particles provides direct evidence for the trimeric nature of intact env surface glycoproteins. three-dimensional image reconstruction reveals that the env trimer is a tapering spike 14 nm in length. the spikes were often arranged in hexagonal rings which shared adjacent env trimers. | 2000 | 10684305 |
| characterization of the r572t point mutant of a putative cleavage site in human foamy virus env. | a putative cleavage site of the human foamy virus (hfv) envelope glycoprotein (env) was altered. transient env expression revealed that the r572t mutant env was normally expressed and modified by asparagine-linked oligosaccharide chains. however, this single-amino-acid substitution was sufficient to abolish all detectable cleavage of the gp130 precursor polyprotein. cell surface biotinylation demonstrated that the uncleaved mutant gp130 was transported to the plasma membrane. the uncleaved mutan ... | 2000 | 10684317 |
| complex effects of deletions in the 5' untranslated region of primate foamy virus on viral gene expression and rna packaging. | due to various advantageous features there is current interest in retroviral vectors derived from primate foamy viruses (pfvs). two pfv cis-acting sequences have been mapped in the 5' region of the rna (pre-)genome and in the 3' pol genomic region. in order to genetically separate pfv packaging constructs from vector constructs, we investigated the effect of deletions in the 5' untranslated region (utr) of pfv packaging constructs and vectors on gene expression and rna incorporation into viral p ... | 2000 | 10708430 |
| isolation and characterization of an equine foamy virus. | foamy viruses (fvs) are complex retroviruses which have been isolated from different animal species including nonhuman primates, cattle, and cats. here, we report the isolation and characterization of a new fv isolated from blood samples of horses. similar to other fvs, the equine foamy virus (efv) exhibits a highly characteristic ultrastructure and induces syncytium formation and subsequent cell lysis on a large number of cell lines. molecular cloning of efv reveals that the general organizatio ... | 2000 | 10756018 |
| induction of cellular genes is mediated by the bel1 transactivator in foamy virus-infected human cells. | to gain insight into human foamy virus (hfv; also called spumaretrovirus)-induced alterations of cellular genes, the expression profiles of defined genes in hfv-infected primary human cells were analyzed by cdna array assays. several distinct cellular genes activated by hfv infection were identified; the identities of the cellular genes were confirmed by rna blot analyses. compared with mock-infected controls, the concentrations of cellular kip2, egr-1, coup-tf1, insulin-like growth factor ii (i ... | 2000 | 10775579 |
| an evolutionarily conserved positively charged amino acid in the putative membrane-spanning domain of the foamy virus envelope protein controls fusion activity. | foamy viruses (fvs) are highly fusogenic, and their replication induces massive syncytium formation in infected cell cultures which is believed to be mediated by expression of the envelope (env) protein. the fv env is essential for virus particle egress. the unusually long putative membrane-spanning domain (msd) of the transmembrane subunit carries dispersed charged amino acids and has an important function for particle envelopment. to better understand the capsid-envelope interaction and env-me ... | 2000 | 10775583 |
| strain fv-21 of simian foamy virus type 1 was cloned and sequenced after isolation from the taiwan monkey macaca cyclopsis. | 2000 | 10806968 | |
| foamy viruses: between retroviruses and pararetroviruses. | 2000 | 10814564 | |
| why aren't foamy viruses pathogenic? | foamy viruses are complex retroviruses that lead to either highly cytopathic or persistent infections in vitro, but to non-pathogenic lifelong infections in naturally or accidentally infected hosts. factors that could contribute to these benign persistent infections include regulated transcription from the two viral promoters, the functions of the bet accessory protein and the host immune response. | 2000 | 10838587 |
| [risk and risk management connected with xenograft]. | transmission of an animal virus to man is probably a constant reality. pathogenicity is is not inevitable. some vaccines were contaminated by cell culture but remain safe. haemorrhagic fevers, despite limited outbreaks, are often cited in the media. on the other hand, the influenza a virus has been responsible for a large mortality. the cases of human infection with simian viruses (herpes virus b, cytomegalovirus, spumavirus, immunodeficiency virus) were accidental and have always remained asymp ... | 2000 | 10868407 |
| efficient intracellular retrotransposition of an exogenous primate retrovirus genome. | the foamy virus (fv) subgroup of retroviridae reverse transcribe their rna (pre-)genome late in the replication cycle before leaving an infected cell. we studied whether a marker gene-transducing fv vector is able to shuttle to the nucleus and integrate into host cell genomic dna. while a potential intracellular retrotransposition of vectors derived from other retroviruses was below the detection limit of our assay, we found that up to 5% of cells transfected with the fv vector were stably trans ... | 2000 | 10880456 |
| detection of reverse transcriptase activity in the serum of patients with motor neurone disease. | the recognition that both human and murine retroviruses can cause motor neurone disease-like syndromes has raised the possibility that a retrovirus may be involved in the aetiology of motor neurone disease. this possibility was explored by looking for evidence of reverse transcriptase in the serum of motor neurone disease patients. sera from 56 patients with motor neurone disease and 58 controls were tested by the product-enhanced reverse transcriptase assay, a technique that is approximately a ... | 2000 | 10897073 |
| mutational analysis of the 5' leader region of simian foamy virus type 1. | 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 ... | 2000 | 10936101 |
| poised for contagion: evolutionary origins of the infectious abilities of invertebrate retroviruses. | phylogenetic analyses suggest that long-terminal repeat (ltr) bearing retrotransposable elements can acquire additional open-reading frames that can enable them to mediate infection. whereas this process is best documented in the origin of the vertebrate retroviruses and their acquisition of an envelope (env) gene, similar independent events may have occurred in insects, nematodes, and plants. the origins of env-like genes are unclear, and are often masked by the antiquity of the original acquis ... | 2000 | 10984449 |
| contrastive prevalence of feline retrovirus infections between northern and southern vietnam. | the prevalence of infections with three feline retroviruses; feline leukemia virus (felv), feline immunodeficiency virus (fiv) and feline foamy virus (fefv), was examined in domestic cats (felis catus) and leopard cats (felis bengalensis) in southern vietnam in 1998. we then compared this data with our previous study in northern vietnam in 1997. none of the cats had felv antigens in both the northern and southern areas. in contrast, there is a great distinction in the seropositivity of fiv. twen ... | 2000 | 10993195 |
| characterization of the humoral immune response and virus replication in cats experimentally infected with feline foamy virus. | cats were experimentally infected with cell culture-adapted feline foamy virus (ffv, spumaretrovirinae) isolate fuv. ffv was consistently recovered from peripheral blood leukocytes and throat samples of ffv-infected cats starting 2 to 3 weeks postinfection (p. i.), indicative of the establishment of persistent ffv infections. viral persistence was established, even despite neutralizing antibodies that appeared early after infection. the humoral immune response toward ffv was quantitatively and q ... | 2000 | 11017797 |
| malignant catarrhal fever: polymerase chain reaction survey for ovine herpesvirus 2 and other persistent herpesvirus and retrovirus infections of dairy cattle and bison. | using a polymerase chain reaction (pcr) test for sequences of ovine herpesvirus 2 (ohv2), this virus was shown to be significantly associated with sheep-associated malignant catarrhal fever (sa-mcf) in terminal cases of disease in 34 cattle and 53 bison. ovine herpesvirus 2 was not detected in cattle (38) and bison (10) that succumbed to other diseases. other persistent herpesviruses, retroviruses, and pestivirus, some of which have been previously isolated from cases of sa-mcf, were not associa ... | 2000 | 11021426 |
| antibody to human foamy virus not detected in individuals treated with blood products or in blood donors. | 2000 | 11054053 | |
| primate foamy virus pol proteins are imported into the nucleus. | mouse monoclonal antibodies (mabs) that specifically detect the 127 kda pol precursor and the 85 kda reverse transcriptase/rnase h (rt/rn) or pr127 and the 40 kda integrase (in) in immunoblot and immunofluorescence assays (ifa) were used to investigate the subcellular localization of primate foamy virus (pfv) proteins. ifa of cells infected with pfv using the anti-pol mabs and rabbit anti-capsid (gag) serum revealed that both the gag and pol proteins are transported into the nucleus. transfectio ... | 2000 | 11086125 |
| simian foamy virus infections in a baboon breeding colony. | 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 3 ... | 2000 | 11112493 |
| human foamy virus bel 1 transactivator/estrogen receptor fusion proteins allow inducible transactivation of both human foamy virus promoters. | recombinant plasmids that express human foamy virus (hfv) bel 1 transactivator and human estrogen receptor (er) fusion proteins were constructed. the hfv bel 1 gene was inserted up- and downstream of the er gene. recombinant bel 1-er and er-bel 1 fusion proteins were expressed in eukaryotic cells. in the absence of estrogen, the er moiety of the fusion proteins suppressed bel 1-mediated transactivation as measured in cat reporter gene-based transactivation assays. however, transactivation of the ... | 2000 | 11129637 |
| historical perspective of foamy virus epidemiology and infection. | foamy viruses (fv) are complex retroviruses which are widespread in many species. despite being discovered over 40 years ago, fv are among the least well characterized retroviruses. the replication of these viruses is different in many interesting respects from that of all other retroviruses. infection of natural hosts by fv leads to a lifelong persistent infection, without any evidence of pathology. a large number of studies have looked at the prevalence of primate foamy viruses in the human po ... | 2001 | 11148008 |
| the efficiency of simian foamy virus vector type-1 (sfv-1) in nondividing cells and in human pbls. | current retroviral vectors based on murine leukemia virus (mulv) are unable to efficiently transduce nondividing cells. lentiviruses, such as the human immunodeficiency virus 1 (hiv-1) are efficient at transducing nondividing, growth-arrested, and post-mitotic cells, but due to complex safety considerations, they may have limited potential for human clinical gene transfer. for this reason, alternatives to mulv and hiv-1 vectors need to be explored. in this paper, we have found that simian foamy ... | 2001 | 11162838 |
| characterization of peptide substrates and viral enzyme that affect the cleavage site specificity of the human spumaretrovirus proteinase. | oligopeptides that correspond to proteolytic cleavage site junctions of the native gag and pol proteins are specifically cleaved by retroviral aspartate proteases (prs). the role of the flap subdomain of the pr of the human spumaretrovirus (hsrv) and of substrate peptides in cleavage site specificity was analyzed by site-directed mutagenesis. native and mutant peptides were subjected to proteolysis by the authentic and mutated recombinant viral enzyme. the results reveal that glu residue 54 of t ... | 2001 | 11210941 |
| progress towards hematopoietic stem cell gene therapy. | the introduction of recombinant genetic material into human cells for therapeutic purposes offers tremendous potential. however, almost from the beginning, the application of gene therapy has been characterized by the striking discrepancy between its promise and realization. over the past 15 years, much has been learned about the various gene transfer systems and the requirements for efficient hematopoietic stem cell gene transfer. in the current review, we will summarize recent improvements in ... | 2000 | 11249770 |
| palindromic sequence plays a critical role in human foamy virus dimerization. | the retroviral rna genome is dimeric, consisting of two identical strands of rna linked near their 5' ends by a dimer linkage structure. previously it was shown that human foamy virus (hfv) rna transcribed in vitro contained three sites, designated si, sii, and siii, which contributed to the dimerization process (o. erlwein, d. cain, n. fischer, a. rethwilm, and m. o. mcclure, virology 229:251-258, 1997). to characterize these sites further, a series of mutants were designed and tested for their ... | 2001 | 11264362 |
| human foamy virus capsid formation requires an interaction domain in the n terminus of gag. | retroviral gag expression is sufficient for capsid assembly, which occurs through interaction between distinct gag domains. human foamy virus (hfv) capsids assemble within the cytoplasm, although their budding, which mainly occurs in the endoplasmic reticulum, requires the presence of homologous env. yet little is known about the molecular basis of hfv gag precursor assembly. using fusions between hfv gag and a nuclear reporter protein, we have identified a strong interaction domain in the n ter ... | 2001 | 11287585 |
| reactivation of feline foamy virus from a chronically infected feline renal cell line by trichostatin a. | although acute infection of feline foamy virus (fefv) is normally highly cytopathogenic in crandell feline kidney (crfk) cells, a noncytopathic persistent infection was established in the cells after cocultivation of the initially infected cells with uninfected cells four times. to investigate reactivation of persistent infection, crfk cells chronically infected with fefv were treated with trichostatin a (ta), a histone deacetylase inhibitor. ta induced higher fefv production from the coleman st ... | 2001 | 11336556 |
| a quantitative assay for measuring human foamy virus using an established indicator cell line. | in order to improve the accuracy for detecting human foamy virus (hfv), an indicator cell line was established by co-transfecting baby hamster kidney-21 cells with two plasmids: one containing a g418 antibiotic resistance marker and the other including the luc gene which was placed downstream of the inducible hfv long terminal repeat promoter (from -533 to +20). among 11 independent subclones, idb14 was found to be stable with a low basal level of luciferase activity. although the changes in luc ... | 2001 | 11337050 |
| a particle-associated glycoprotein signal peptide essential for virus maturation and infectivity. | signal peptides (sp) are key determinants for targeting glycoproteins to the secretory pathway. here we describe the involvement in particle maturation as an additional function of a viral glycoprotein sp. the sp of foamy virus (fv) envelope glycoprotein is predicted to be unusually long. using an sp-specific antiserum, we demonstrate that its proteolytic removal occurs posttranslationally by a cellular protease and that the major n-terminal cleavage product, gp18, is found in purified viral par ... | 2001 | 11390578 |
| factors contributing to the fusogenic potency of foamy virus. | three model peptides have been studied in an effort to understand the molecular basis for the fusogenic potency of foamy virus. these peptides corresponded to a 23 amino acid helical segment close to the amino terminus, a shortened 17 amino acid, more hydrophobic homolog of this peptide, and an 18-amino-acid peptide close to or within the transmembrane domain. the peptides have a conformation containing both alpha-helical and beta-structure in aqueous solution but are predominantly alpha-helical ... | 2001 | 11409874 |
| genetic analyses of feline foamy virus isolates from domestic and wild feline species in geographically distinct areas. | to know the genetic diversities and phylogenetic relationship among feline foamy virus (fefv) isolates from domestic cats (felis catus) and fefv-related viruses from the iriomote cats (felis iriomotensis) and leopard cats (felis bengalensis) in geographically distinct areas, we sequenced a partial gag-pol region of 17 strains and a partial env region of nine strains, and the u3 region of long terminal repeat of three strains of the viruses. fefv-related viruses from the feral cats were quite sim ... | 2001 | 11410316 |
| cell-type-specific regulation of the two foamy virus promoters. | the foamy virus (fv) genome contains two promoters, the canonical long terminal repeat (ltr) promoter, containing three consensus ap-1 binding sites, and an internal promoter (ip) within the env gene. we investigated the regulation of the two promoters in lytic and persistent infections and found that in the presence of a constitutive source of the viral transactivator protein tas, transactivation of the ltr promoter and that of the ip differ. in lytic infections, both the ltr promoter and the i ... | 2001 | 11413322 |
| pml mediates the interferon-induced antiviral state against a complex retrovirus via its association with the viral transactivator. | the promyelocytic leukaemia (pml) protein localizes in the nucleus both in the nucleoplasm and in matrix-associated multiprotein complexes known as nuclear bodies (nbs). the number and the intensity of pml nbs increase in response to interferon (ifn). overexpression of pml affects the replication of vesicular stomatitis virus and influenza virus. however, pml has a less powerful antiviral activity against these viruses than the ifn mediator mxa. here, we show that overexpression of pml, but not ... | 2001 | 11432836 |
| the r region found in the human foamy virus long terminal repeat is critical for both gag and pol protein expression. | it has been suggested that sequences located within the 5' noncoding region of human foamy virus (hfv) are critical for expression of the viral gag and pol structural proteins. here, we identify a discrete approximately 151-nucleotide sequence, located within the r region of the hfv long terminal repeat, that activates hfv gag and pol expression when present in the 5' noncoding region but that is inactive when inverted or when placed in the 3' noncoding region. sequences that are critical for th ... | 2001 | 11435560 |
| identification of a conserved residue of foamy virus gag required for intracellular capsid assembly. | in contrast to all retroviruses but similar to the hepatitis b virus, foamy viruses (fv) require expression of the envelope protein for budding of intracellular capsids from the cell, suggesting a specific interaction between the gag and env proteins. capsid assembly occurs in the cytoplasm of infected cells in a manner similar to that for the b- and d-type viruses; however, in contrast to these retroviruses, fv gag lacks an n-terminal myristylation signal and capsids are not targeted to the pla ... | 2001 | 11435565 |
| efficacy of dideoxynucleosides against human foamy virus and relationship to its reverse transcriptase amino acid sequence and structure. | human foamy virus (hfv), a retrovirus of simian origin which occasionally infects humans, is the basis of retroviral vectors in development for gene therapy. clinical considerations of how to treat patients developing an uncontrolled infection by either hfv or hfv-based vectors need to be raised. we determined the susceptibility of the hfv to dideoxynucleosides and found that only zidovudine was equally efficient against the replication of human immunodeficiency virus type 1 (hiv-1) and hfv. by ... | 2001 | 11435599 |
| gene transfer into murine hematopoietic stem cells with helper-free foamy virus vectors. | gene transfer into hematopoietic stem cells (hscs) is an ideal treatment strategy for many genetic and hematologic diseases. however, progress has been limited by the low hsc transduction rates obtained with retroviral vectors based on murine leukemia viruses. this study examined the potential of vectors derived from the nonpathogenic human foamy virus (hfv) to transduce human cd34(+) cells and murine hscs. more than 80% of human hematopoietic progenitors present in cd34(+) cell preparations der ... | 2001 | 11468157 |
| specific interaction of a novel foamy virus env leader protein with the n-terminal gag domain. | cryoelectron micrographs of purified human foamy virus (hfv) and feline foamy virus (ffv) particles revealed distinct radial arrangements of gag proteins. the capsids were surrounded by an internal gag layer that in turn was surrounded by, and separated from, the viral membrane. the width of this layer was about 8 nm for hfv and 3.8 nm for ffv. this difference in width is assumed to reflect the different sizes of the hfv and ffv ma domains: the hfv ma domain is about 130 residues longer than tha ... | 2001 | 11483744 |
| differential susceptibility of retroviruses to nucleoside analogues. | retroviruses may cause diseases in their vertebrate hosts. they are distinguished by their common means of replication involving reverse transcription, a process inhibited by nucleoside reverse transcriptase inhibitors (nrtis) and other compounds used in antiretroviral chemotherapy. previous work on nrtis has been limited to their effect on human immunodeficiency virus (hiv) (for review see ho & hitchcock, 1989; weller, 1999) and little information exists regarding the efficacy and therapeutic p ... | 2001 | 11527046 |
| the bet gene of feline foamy virus is required for virus replication. | foamy viruses (fv) are complex retroviruses with additional bel genes located between env and the 3' long-terminal repeat. the functions of the bel 2 and bet genes are unknown and both are dispensable for replication of the prototypic human foamy virus in cell cultures. we examined the function(s) of bel 2 and bet of the distantly related feline foamy virus (ffv) in the proviral context. mutagenesis was used to alter the bel 2 and bet or to abrogate their expression. the bel 2/bet mutants showed ... | 2001 | 11531409 |
| low-level expression of functional foamy virus receptor on hematopoietic progenitor cells. | foamy viruses have several qualities favorable for vector development: they are not known to cause disease; they can transduce stationary cells; and the foamy virus receptor is expressed on a wide variety of cells. here, we analyzed the level of virus receptor expression on hematopoietic progenitor cells. foamy virus binding was measured by a flow cytometric assay and was found to be considerably reduced in hematopoietic progenitors cell lines as well as in primary cd34(+) cells when compared to ... | 2001 | 11543666 |
| isolation and sequencing of infectious clones of feline foamy virus and a human/feline foamy virus env chimera. | full-length dnas of the coleman and s7801 strains (psky3.0, psky5.0) of infectious feline foamy viruses (ffvs) were cloned and sequenced. parental viruses, designated sky3.0 and sky5.0, were secreted following transfection of crandell feline kidney (crfk) cells. production of the rescued parental viruses was enhanced in the presence of trichostatin a. amino acid sequence similarities between ffv and human foamy virus (hfv) are extremely low for the envelope protein and capsid antigen, as predict ... | 2001 | 11714976 |
| lentivirus and foamy virus vectors: novel gene therapy tools. | the aim of gene therapy is to modify the genetic material of living cells to achieve therapeutic benefit. gene therapy involves the insertion of a functional gene into a cell, to replace an absent or defective gene, or to fight an infectious agent or a tumour. at present, a wide variety of somatic tissues are being explored for the introduction of foreign genes with a view towards treatment. a prime requirement for successful gene therapy is the sustained expression of the therapeutic gene witho ... | 2001 | 11727544 |
| foamy virus replication: implications for interaction with other retroviruses and host cellular sequences. | foamy viruses (fv) comprise one of the seven genera of retroviruses. these viruses infect most non-human primates as well as cats, cows and horses. infections are persistent and life-long, but have no pathogenic consequences. viral replication in vivo is at a very low level, but virus can be recovered years after infection. humans can acquire fv as zoonotic infections which are also life-long. although fv are highly cytopathic to fibroblast cultures, some cell lines can be infected with fv witho ... | 2001 | 11761236 |
| the hiv plus-strand transfer reaction: determination of replication-competent intermediates and identification of a novel lentiviral element, the primer over-extension sequence. | current retroviral replication models propose that during (+) strand synthesis, the initial (-) strand trna primer is partially replicated to reproduce the 18 nt primer-binding site (pbs). subsequent removal of the trna primer from the (-) strand template exposes the pbs, which anneals to complementary sequences on a dna acceptor template to enable (+) strand transfer. we used model templates composed of primed (-) strand dna covalently linked with post-transcriptionally modified trna(3)(lys) al ... | 2002 | 11786014 |
| high similarity between reverse-oriented sequences from hiv and foamy virus envelope glycoproteins. | 2002 | 11860678 | |
| gene transfer with foamy virus vectors. | 2002 | 11883096 | |
| intra- and intercellular trafficking of the foamy virus auxiliary bet protein. | the bet protein of foamy viruses (fvs) is an auxiliary protein encoded by the 3' end of the viral genome. although its function during the viral replication cycle is still unknown, bet seems to play a key role in the establishment and/or maintenance of viral persistence, representing the predominant viral protein detected during chronic infection. to clarify the function of this viral protein, the subcellular distribution of bet from the prototypic human foamy virus (hfv) was examined. we report ... | 2002 | 11884565 |
| improved primate foamy virus vectors and packaging constructs. | foamy virus (fv) vectors that have minimal cis-acting sequences and are devoid of residual viral gene expression were constructed and analyzed by using a packaging system based on transient cotransfection of vector and different packaging plasmids. previous studies indicated (i) that fv gag gene expression requires the presence of the r region of the long terminal repeat and (ii) that rna from packaging constructs is efficiently incorporated into vector particles. mutants with changes in major 5 ... | 2002 | 11907217 |
| simian foamy virus vectors. preparation and use. | 2002 | 11987786 | |
| hematopoietic stem cell gene therapy. | gene therapy applications that target hematopoietic stem cells (hscs) offer great potential for the treatment of hematologic disease. despite this promise, clinical success has been limited by poor rates of gene transfer, poor engraftment of modified cells, and poor levels of gene expression. we describe here the basic approach used for hsc gene therapy, briefly review some of the seminal clinical trials in the field, and describe several recent advances directed toward overcoming these limitati ... | 2002 | 11999349 |
| transduction of human nod/scid-repopulating cells with both lymphoid and myeloid potential by foamy virus vectors. | the efficiency of gene transfer into human hematopoietic stem cells by oncoretroviral vectors is too low for effective gene therapy of most hematologic diseases. retroviral vectors based on the nonpathogenic foamy viruses (fv) are an alternative gene-transfer system. in this study, human umbilical cord blood cd34(+) cells were transduced with fv vectors by a single 10-h exposure to vector stocks and then injected into sublethally irradiated nonobese diabetic-severe combined immunodeficiency (nod ... | 2002 | 12060773 |
| further characterization of equine foamy virus reveals unusual features among the foamy viruses. | foamy viruses (fvs) are nonpathogenic, widely spread complex retroviruses which have been isolated in nonhuman primates, cattle, cats, and more recently in horses. the equine foamy virus (efv) was isolated from healthy horses and was characterized by molecular cloning and nucleotide sequence analysis. here, to further characterize this new fv isolate, the location of the transcriptional cap and poly(a) addition sites as well as the main splice donor and acceptor sites were determined, demonstrat ... | 2002 | 12072521 |
| survival of spumavirus, a primate retrovirus, in laboratory media and water. | the persistence of a previously characterized spumavirus strain (strain sv-522) was investigated utilizing various laboratory media and waters, including eagle's minimal essential medium (emem) plus 0% fetal bovine serum (emem-0%), emem-2%, emem-10%, chlamydia transport medium (ctm), phosphate-buffered saline, distilled, estuarine, and marine water, human serum, and the germicides, ethyl alcohol (70%) and sodium hypochlorite (10%). experiments were performed at 4 degrees c and/or 23 degrees c. i ... | 2002 | 12076814 |
| mutation of the catalytic domain of the foamy virus reverse transcriptase leads to loss of processivity and infectivity. | foamy virus (fv) replication is resistant to most nucleoside analog reverse transcriptase (rt) inhibitors. in an attempt to create a 2',3'-dideoxy-3'-thiacytidine (3tc)-sensitive virus, the second residue in the highly conserved yxdd motif of simian foamy virus-chimpanzee (human isolate) [sfvcpz(hu)] rt was changed from val (v) to met (m). unexpectedly, the resultant virus, sfvcpz(hu) rt-v313m, replicated poorly, and met rapidly reverted to val. despite the presence of approximately 50% of wild- ... | 2002 | 12097569 |
| a new indicator cell line to monitor human foamy virus infection and stability in vitro. | in order to determine the human foamy virus (hfv) infection in vitro conveniently, we developed a baby hamster kidney cell (bhk)-21-derived indicator cell line (bhk-hfvltr-egfp) containing a plasmid that encodes the enhanced green fluorescent protein (egfp) driven by the hfv long terminal repeat promoter. the viral trans-activator bel-1 protein can induce egfp expression, so the hfv titer could be determined by counting the corresponding egfp-positive cells. this foamy-virus-activated egfp expre ... | 2002 | 12145539 |
| pregenomic rna is required for efficient incorporation of pol polyprotein into foamy virus capsids. | the foamy virus (fv) pol polyprotein is translated independently of gag from a spliced mrna. this method of expression raises the question of how pol is associated with the viral particle. using a transient fv vector transfection system, it is shown that pregenomic rna is required for efficient virion incorporation of functionally active pol and that protein-protein interactions of pol with gag are not sufficient to complete particle assembly. | 2002 | 12208988 |
| human foamy virus integrase fails to catalyse the integration of a circular dna molecule containing an ltr junction sequence. | the presence of closed circular forms of the linear dna genome of human foamy virus (hfv) has not been established. the ability of the hfv integrase (in) to catalyse the integration of these circular forms (termed 2 long terminal repeat (ltr) circles) was investigated, with a view to producing a novel hybrid vector. to this end, a construct was made containing, in addition to the enhanced green fluorescent protein (egfp) marker gene, the last 27 bp of the 3' u5 ltr region of hfv fused to the fir ... | 2002 | 12224016 |
| improved foamy virus vectors with minimal viral sequences. | foamy virus (fv) vectors show promise for gene therapy applications. however, existing fv vectors either retain a significant portion of the wild-type virus genome or are produced at low titers. we describe a transient cotransfection system that produces high-titer fv vectors with minimal cis-acting regions. these vector genomes have deletions in the gag, pol, env, and bel1-3 accessory genes, as well as the ltr u3 region, but retain an essential 2.5-kb cis-acting region. in addition, stop codons ... | 2002 | 12231167 |
| cross-species retroviral transmission from macaques to human beings. | cross-species transmission of simian foamy virus (sfv) to human beings from chimpanzees, baboons, and african green monkeys has been described. although macaques are the non-human primate most often handled in research, human infection with sfv from macaques has not been reported. two of 46 primate-facility workers tested positive for antibodies that reacted with an immunoblot that contained macaque foamy virus antigens. phylogenetic assessment of a 96-bp fragment of amplified proviral dna isola ... | 2002 | 12241782 |
| construction and functional characterization of feline foamy virus-based retroviral vectors. | replication-competent feline foamy or spuma virus (ffv) vectors were constructed and functionally tested. the unmodified ffv vector genome expressed by the strong human cytomegalovirus immediate early promoter encodes ffv particles that were replication-competent in cell cultures. virus derived from the cloned ffv dna replicated and persisted in experimentally infected cats similar to the ffv isolate fuv. a ffv vector partially deleted in the noncoding area of the u3 region was used to transduce ... | 2002 | 12359446 |
| structural features of prions explored by sequence analysis i. sequence data. | animal prion proteins (prps) form at the sequence level a very homogenous and 'closed' family. therefore, few of their structural and functional features can be gleaned from sequence comparison as is now possible on a wide scale for other protein families. to detect putatively related proteins (at the structural and/or functional level), we used a battery of sequence analysis tools. this analysis resulted in (i) the identification of a putative 'prion-like' domain within the envelope of foamy re ... | 2002 | 12363039 |
| simian foamy virus infection in a blood donor. | infections with simian foamy virus (sfv) are widely prevalent in nonhuman primates. sfv infection was confirmed in a worker, occupationally exposed to nonhuman primates, who donated blood after the retrospectively documented date of infection. human-to-human transmission of sfv through transfusion and its pathogenicity have not been studied. | 2002 | 12375661 |
| reactivation of a complex retrovirus is controlled by a molecular switch and is inhibited by a viral protein. | spumaviruses, commonly called foamy viruses (fv), are complex retroviruses that establish lifelong persistent infections without any accompanying pathologies. in tissue culture, cells can be either lytically or latently infected, depending on cell type. regulation of fv replication is controlled by two promoters: the ltr and a second promoter within the env gene termed the internal promoter (ip). the ip directs expression of the transcriptional activator, tas, and a second accessory protein, bet ... | 2002 | 12415120 |
| transduction of umbilical cord blood cd34+ nod/scid-repopulating cells by simian foamy virus type 1 (sfv-1) vector. | foamy viruses are nonpathogenic retroviruses that offer unique opportunities for gene transfer into various cell types including hematopoietic stem cells. we used a simian foamy virus type 1 vector (sfv-1) containing a lacz reporter gene with a titer of 1-5 x 10(6) viral particles/ml that was free of replication-competent retrovirus to transduce human umbilical cord blood cd34+ cells. transduced cd34+ cord blood cells were transplanted into nod/scid mice and plated in serum-free methylcellulose ... | 2002 | 12441067 |
| a minimal genome simian foamy virus type 1 vector system with efficient gene transfer. | foamy viruses have several inherent features for the opportunity to develop efficient and versatile vectors for gene therapy. we have constructed a series of vectors and helper plasmids based on simian foamy virus type 1 (sfv-1) to establish the minimum vector genome required for efficient gene transduction. to characterize the efficiency of gene transduction by these vectors, the green fluorescent protein (gfp) coding sequence is linked to the human cytomegalovirus immediate gene promoter. seve ... | 2002 | 12441068 |
| bel1-mediated transactivation of the spumaretroviral internal promoter is repressed by nuclear factor i. | gene expression of the internal and long terminal repeat promoters of the spuma retrovirus is specifically activated by the transactivator bel1, the key regulator of viral gene expression. bel1 directly binds to and activates dna target sites of viral promoters and those of distinct cellular genes. to determine the contribution of cellular transcription factors to viral transactivation, the viral internal promoter (ip) was analyzed by transient expression, electrophoretic mobility shift assays), ... | 2003 | 12446690 |
| the promyelocytic leukemia protein does not mediate foamy virus latency in vitro. | spumaviruses, commonly called foamy viruses, are complex retroviruses that establish life-long persistent infections in the absence of accompanying pathology. depending upon cell type, infection of cells in tissue culture cells can result in either lytic replication, persistence, or latency. the cellular factors that mediate foamy virus (fv) latency are poorly understood. in this study we show that the only known inhibitor of fv replication, the promyelocytic leukemia protein (pml), which binds ... | 2003 | 12525655 |
| development of foamy virus vectors. | 2003 | 12526184 | |
| foamy virus envelope glycoprotein is sufficient for particle budding and release. | foamy viruses (fvs) are classified in the family retroviridae, but recent data have shown that they are not conventional retroviruses. notably, several characteristics of their particle replication strategies are more similar to those of hepatitis b virus (hbv) than those of typical retroviruses. compared to conventional retroviruses, which require only gag proteins for budding and release of virus-like particles (vlps), both fv and hbv require env proteins. in the case of hbv, env (s protein) a ... | 2003 | 12551971 |
| isolation of cytomegalovirus and foamy virus from the drill monkey (mandrillus leucophaeus) and prevalence of antibodies to these viruses amongst wild-born and captive-bred individuals. | drill monkeys (mandrillus leucophaeus) are an endangered species whose indigenous viral flora is largely unknown. we report here the isolation and characterization of both a cytomegalovirus (drcmv) and a foamy virus (sfv-drl) from drill monkeys. phylogenetic analysis of dna sequence data placed the drcmv within a primate cmv clade, and showed that sfv-drl was closely related to baboon foamy viruses. elisa analysis demonstrated that drcmv shared common epitopes with other primate cmvs but was dis ... | 2003 | 12607096 |