Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| foamy virus vectors. | human foamy virus (hfv) is a retrovirus of the spumavirus family. we have constructed vectors based on hfv that encode neomycin phosphotransferase and alkaline phosphatase. these vectors are able to transduce a wide variety of vertebrate cells by integration of the vector genome. unlike vectors based on murine leukemia virus, hfv vectors are not inactivated by human serum, and they transduce stationary-phase cultures more efficiently than murine leukemia virus vectors. these properties, as well ... | 1996 | 8523528 |
| a serological survey of bovine syncytial virus in ontario: associations with bovine leukemia and immunodeficiency-like viruses, production records, and management practices. | of the 920 cows tested, 56.7% showed antiretroviral serological reactivity. prevalence rates (95% confidence interval) of antiretroviral antibodies among individual dairy cows in ontario were: biv 5.5% (4.0-7.0), blv 25.7% (22.9-28.6), and bsv 39.6% (36.4-42.8). the following percentages of cows showed serological reactivity against the specified retroviruses: biv 2.3%, blv 14.0%, bsv 27.5%, biv and bsv 1.3%, biv and blv 0.9%, blv and bsv 9.9%, biv and blv and bsv 0.9%. these rates of sero-posit ... | 1995 | 8548688 |
| the human foamy virus pol gene is expressed as a pro-pol polyprotein and not as a gag-pol fusion protein. | it has been reported recently that the human foamy virus (hfv) pol polyprotein of 120 kda is synthesized in the absence of the active hfv aspartic protease. to gain more information on how the 120-kda pro-pol protein is synthesized, mutant hfv genomes were constructed and the resulting proviruses were analyzed with respect to hfv pol expression and infectivity. hfv proviruses that contain termination codons in the nucleocapsid domain of gag and thus lack a gag-pol overlap region assumed to be re ... | 1996 | 8551561 |
| productive persistent infection of hematopoietic cells by human foamy virus. | human foamy virus can establish persistent infections in human hematopoietic cell lines, such as h92.1.7 (erythroblastoid cells), jurkat (cd4+ t cells), and u937 (myeloid-monocytic cells). the infection is characterized by constant production of infectious viruses (for > 2 1/2 years) with no cytopathic effects on the host cells. electron microscopy of the infected cells showed a viral morphology similar to that observed for particles produced after acute infection. we have detected, in addition ... | 1996 | 8551590 |
| the transcriptional transactivator of simian foamy virus 1 binds to a dna target element in the viral internal promoter. | the transcriptional transactivator (tas) of simian foamy virus type 1 strongly augments gene expression directed by both the promoter in the viral long terminal repeat and the newly discovered internal promoter located within the env gene. a region of 121 bp, located immediately 5' to the tata box in the internal promoter, is required for transactivation by tas. the present study aimed to identify the precise tas-responsive target(s) in this region and to determine the role of tas in transcripti ... | 1996 | 8552631 |
| infectious proviral clones of chimpanzee foamy virus (sfvcpz) generated by long pcr reveal close functional relatedness to human foamy virus. | infectious proviral clones of simian foamy virus isolated from chimpanzee (sfvcpz) were generated by long pcr. two overlapping fragments representing the complete provirus were amplified from genomic dna of infected cells. four 8.8-kbp amplimers extending from base 1 of the provirus into the env gene and five 4.45-kbp amplimers reaching from env to the end of the 3'-ltr were cloned into pcr ii. subsequently, the proviral fragments were combined in a chessboard manner to generate 20 plasmids cont ... | 1995 | 8553577 |
| absence of association between human spumaretrovirus and graves' disease. | graves' disease (gd) is an autoimmune thyroid disease. the etiology of gd is still not clear. both genetic and environmental factors, such as infectious agents, are believed to be involved in its pathogenesis. recent findings suggest a role for human spumaretrovirus (hsrv) in the pathogenesis of gd. to test this hypothesis, we looked for the hsrv gag region sequence in dna extracted from the peripheral blood leukocytes and thyroid tissue of patients with gd, and controls. genomic dna was subject ... | 1995 | 8563476 |
| human foamy virus replication: a pathway distinct from that of retroviruses and hepadnaviruses. | human foamy virus (hfv) is the prototype of the spumavirus genus of retroviridae. in all other retroviruses, the pol gene products, including reverse transcriptase, are synthesized as gag-pol fusion proteins and are cleaved to functional enzymes during viral budding or release. in contrast, the pol protein of hfv is translated from a spliced messenger rna and lacks gag domains. infectious hfv particles contain double-stranded dna similar in size to full-length provirus, suggesting that reverse t ... | 1996 | 8599113 |
| analysis of the determinants of neurotropism and neurotoxicity of hfv in transgenic mice. | the bel-1 protein of human foamy virus (hfv) is a transactivator acting on the u3 region of the long terminal repeat and on an internal promoter (ip) immediately upstream of the bel genes. an hfv transgene called delta gpe, containing both promoters and all bel genes, is expressed in the central nervous system and induces neurodegeneration in mice. to dissect the role of individual promoters and bel genes on transgene expression and neurotoxicity we generated transgenic mice with a construct ter ... | 1996 | 8607263 |
| regulation of expression and pathogenic potential of human foamy virus in vitro and in transgenic mice. | 1996 | 8608720 | |
| in vitro infection of primary and retrovirus-infected human leukocytes by human foamy virus. | the infectivity of human foamy virus (hfv) was examined in primary and cultured human leukocytes. cell-free infectious viral stocks of hfv were prepared from the human kidney cell line 293 transfected with an infectious molecular clone of hfv. hfv productively infects a variety of human myeloid and lymphoid cell lines. in addition, primary cell cultures enriched for human cd4+, monocytes and brain-derived microglial cells, were readily infected by hfv. interestingly, while infected primary cd4+ ... | 1996 | 8627751 |
| foamy virus reverse transcriptase is expressed independently from the gag protein. | 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 po ... | 1996 | 8633029 |
| reverse transcription. foamy viruses bubble on. | 1996 | 8637564 | |
| the human foamy virus bel-1 transcription factor is a sequence-specific dna binding protein. | the bel-1 transcriptional transactivator encoded by human foamy virus (hfv) can efficiently activate gene expression directed by both the hfv long terminal repeat (ltr) and internal (int) promoter elements. by dna footprinting and gel retardation analysis, we demonstrate that bel-1 can specifically bind to discrete sites in both the ltr and int promoter elements in vitro. however, transactivation of the hfv ltr by bel-1 was observed to require not only the promoter-proximal bel-1 binding site id ... | 1996 | 8648727 |
| lymphocytes are the major reservoir for foamy viruses in peripheral blood. | simian and human foamy virus (fv) dna can be readily detected in peripheral blood leukocytes. however, it is unknown which leukocyte populations harbor the virus in vivo. we, therefore, analyzed blood samples from nine african green monkeys, four chimpanzees, and two humans for the presence of foamy virus proviral dna in different facs-purified leukocyte populations, using a highly sensitive nested polymerase chain reaction (pcr). the cd8+ lymphocytes were pcr positive in all 15 samples and the ... | 1996 | 8661433 |
| transactivation of the two promoters of sfv-3 by different mechanisms. | simian foamy virus type 3 (sfv-3), a member of the spumavirus genus of retroviruses, has a complex genome organization and encodes two open reading frames (orfs), in addition to the structural genes gag, pol, and env. orf-1 encodes a viral transcriptional transactivator designated taf (transactivator of foamy viruses) which augments transcription from the viral long terminal repeat (ltr). it was recently shown that human foamy virus, as well as the simian viruses sfv-1 and sfv-3, contains a seco ... | 1996 | 8661448 |
| viral infections of the feline urinary tract. | the exact cause of hematuria, dysuria, and urethral obstruction remains unknown in a large percentage of naturally occurring cases of feline lower urinary tract disease (flutd). one attractive hypothesis implicates viruses as the cause of some idiopathic forms of flutd; supporting this hypothesis is the fact that a gamma herpesvirus, a calicivirus, and a retrovirus have been isolated from urine and tissues obtained from cats with this type of disease. although the clinical course and laboratory ... | 1996 | 8711863 |
| cell tropism of the simian foamy virus type 1 (sfv-1). | 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 characterist ... | 1996 | 8740945 |
| the simian foamy virus type 1 transcriptional transactivator (tas) binds and activates an enhancer element in the gag gene. | simian and human foamy viruses (sfv and hfv) encode a transcriptional transactivator, tas, which governs the levels of viral transcripts initiated by both the promoter in the long terminal repeat (ltr) and the internal promoter (ip) located within the env gene of these viruses. tas-responsive target elements,(tre) ltr in the ltr and (tre) ip in the env gene, are located 5' of the tata box in both viral promoters and function as orientation- and position-independent enhancers. we have identified ... | 1996 | 8794326 |
| unexpected replication pathways of foamy viruses. | foamy viruses make up a distinct subgroup of retroviruses. they are widely distributed among nonhuman primates, felines, and bovines. in their natural hosts and in cases of rare zoonotic transmissions to humans foamy viruses cause persistent and apparently benign infections. while foamy viruses are not of medical importance in causing human or animal diseases, they may become valuable tools for somatic gene transfer in the future. however, a better understanding of the molecular biology of this ... | 1996 | 8797731 |
| molecular biology of the human foamy virus. | 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. | 1996 | 8797732 |
| absence of serological evidence for foamy virus infection in patients with amyotrophic lateral sclerosis. | foamy virus (fv) infection has been implicated in the pathogenesis of sporadic motor neuron disease (mnd) by means of serological assays. to confirm these results we tested serum and cerebrospinal fluid (csf) samples from 23 cases of clinically verified non-familial mnd and 11 cases of suspected non-familial mnd for the presence of fv infection as determined by western blot (wb) and indirect immunofluorescence assay (ifa). using the same tests we also screened sera from 87 healthy chimpanzees fo ... | 1996 | 8801281 |
| functional analysis of human spuma retrovirus genome. | human spuma retrovirus (hsrv) belongs to retroviruses that possess a complex genome organization. hsrv carries at least three extra genes in the region between env and the 3' long terminal repeat, which are not found in simple retroviruses. via alternative splicing, these hsrv genes can encode several proteins. to genetically study the requirements of these viral proteins for viral replication in tissue cultures, a number of mutant viruses were constructed from an infectious molecular clone of h ... | 1995 | 8808330 |
| analysis of the phylogenetic placement of different spumaretroviral genes reveals complex pattern of foamy virus evolution. | 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 th ... | 1995 | 8828144 |
| expression of human foamy virus reverse transcriptase involves a spliced pol mrna. | in human foamy virus (hfv) the reverse transcriptase is expressed independently of the gag protein as a 127-kda pol precursor molecule. evaluating the mechanism of pol expression we identified a spliced mrna which uses the main 5' splice donor and a splice acceptor site located in the gag gene. the significance of this spliced transcript for hfv pol expression was studied by constructing a virus with a mutated splice acceptor site. this virus was unable to express detectable pol proteins after t ... | 1996 | 8862427 |
| isolation and characterization of infectious full-length dna clones of chimpanzee foamy viruses sfv6 and sfv7: evidence for a taf-dependent internal promoter. | 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 repli ... | 1996 | 8882337 |
| in vitro studies on interferon-inducing capacity and sensitivity to ifn of human foamy virus. | we demonstrate in this article that human foamy virus (hfv) fails to induce interferon (ifn) production in two different human tissue culture cell lines: u373-mg and av3. we also show the effect of human alpha-, beta- and gamma ifn on the multiplication cycle of hfv. treatment of cells with 100 iu/ml of any ifn led to strong inhibition of an hfv-induced cytopathic effect. this effect was associated with a significant diminution of reverse transcriptase activity in supernatant fluids of ifn-treat ... | 1996 | 8882338 |
| no evidence of antibody to human foamy virus in widespread human populations. | the first human foamy virus (hfv) to be described was isolated from nasopharyngeal carcinoma tissue from a kenyan patient. early seroepidemiology concluded that there was a significant infection rate, particularly among africans. awareness of foamy viruses as potential vectors has stimulated interest in the natural seroprevalence of hfv infection. we, therefore, investigated the prevalence of hfv infection in more than 5000 human sera collected from diverse populations. to maximize the chances o ... | 1996 | 8893055 |
| inhibition of the in vitro infectivity and cytopathic effect of human foamy virus by dideoxynucleosides. | human foamy virus (hfv) is a human retrovirus that has not been clearly associated with human disease. in this study, we tested the capacity of nucleoside derivatives to inhibit the infectivity and cytopathic effect of hfv in t-lymphoblastoid cells in vitro. h9 cells showed a dramatic cytopathic effect 3 weeks after exposure to hfv. at this time, viral infection was demonstrated by detection of viral antigens by immunofluorescence staining, release of reverse transcriptase activity (rt) in the s ... | 1996 | 8893056 |
| human endogenous retroviruses. | 1996 | 8894353 | |
| transduction of hematopoietic cells by foamy virus vectors. | foamy viruses are retroviruses of the spumavirus family that are often isolated from primary cultures of primate cells. we previously constructed vectors based on human foamy virus (hfv) and found that they were able to transduce a wide variety of vertebrate cells by integration of the vector genome. here we show that several types of hematopoietic cells are efficiently transduced by an hfv vector that encodes alkaline phosphatase (ap). these cell types include transformed cell lines and primary ... | 1996 | 8896436 |
| analysis of west african hunters for foamy virus infections. | foamy viruses are a genus of complex retroviruses that infect a wide variety of mammals. however, a clear association with any disease process has yet to be proven for these viruses. a higher human seroprevalence was reported in african populations, perhaps due to exposure to simian foamy viruses (sfv) endemic in primates. however, the earlier serologic surveys were not confirmed by studies employing nucleic acid amplification. foamy virus infections of humans clearly do occur as rare zoonoses a ... | 1996 | 8959250 |
| the carboxyl terminus of the human foamy virus gag protein contains separable nucleic acid binding and nuclear transport domains. | the gag protein of human foamy virus (hfv) lacks cys-his boxes present in the nucleocapsid (nc) domains of other retroviruses; instead it contains three glycine-arginine-rich motifs (gr boxes). we have expressed the carboxyl end of hfv gag containing the gr boxes (the nc domain equivalent) and analyzed its nucleic acid binding properties. our results show that the nc domain of hfv gag binds with high affinity to both rna and dna, in a sequence-independent manner, as determined by filter binding ... | 1996 | 8970944 |
| 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. | 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. t ... | 1996 | 8971036 |
| a sorting motif localizes the foamy virus glycoprotein to the endoplasmic reticulum. | 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 moti ... | 1997 | 8985416 |
| nuclear targeting of incoming human foamy virus gag proteins involves a centriolar step. | the pathways used in the transport of retroviral genomes to the nucleus are poorly identified. analyzing the intracellular localization of incoming foamy viruses, we have found that the gag antigens and the viral genome accumulate in a distinct perinuclear domain identified as the centrosome. colchicine treatment completely abolished pericentriolar targeting of human foamy virus (hfv) proteins, suggesting a role for microtubules in the transport of the incoming viral proteins to the centrioles. ... | 1997 | 8995637 |
| expression and maturation of human foamy virus gag precursor polypeptides. | in this report, we address the processing of the gag polypeptides of human foamy virus previously reported to be atypical. in the cytoplasm or the nucleus of infected cells as well as in free virus particles, two gag precursor polypeptides were identified at approximately 72 and 68 kda, p72 giving rise to p68 by a maturation process. efficient maturation of gag precursors was observed only in two situations: (i) during the early steps of virus adsorption and (ii) under experimental conditions, i ... | 1997 | 8995691 |
| nonhuman primate spumavirus infections among persons with occupational exposure--united states, 1996. | nonhuman primate (nhp) species used in biomedical research may be infected with a variety of retroviruses including simian immunodeficiency virus (siv), simian spumaviruses (i.e., simian foamy viruses [spv]), simian t-lymphotrophic viruses (stlv), and/or simian type d retroviruses. all of these retroviruses cause life-long infections in nhps, and some are transmissible through sexual contact, blood, or breast-feeding. following the detection of siv infection in a worker with occupational exposur ... | 1997 | 9045042 |
| from the centers for disease control and prevention. nonhuman primate spumavirus infections among persons with occupational exposure--united states, 1996. | 1997 | 9052695 | |
| characterization of human foamy virus proteins expressed by recombinant vaccinia viruses. | we report the generation of recombinant vaccinia viruses (vvs) expressing the gag, pol, bel-1, and bet open reading frames of human foamy virus (hfv), and the establishment of a transient, vv-t7 rna polymerase-directed expression system for the hfv env gene. the correct expression of the hfv proteins was demonstrated by radioimmunoprecipitation using monospecific rabbit antisera, by analysis of the subcellular distribution (for vvgag, vvpol, vvbel-1, and vvbet), and by the ability to induce sync ... | 1997 | 9100994 |
| long-term persistent infection of domestic rabbits by the human foamy virus. | human foamy virus (hfv) belongs to the spumaretrovirus group of the retroviridae taxonomic family. attempts to associate hfv or other foamy viruses to a specific pathology still remain unsuccessful. however, viral gene expression as well as tissue-specific tropism in an in vivo context remain poorly analyzed. to address this issue, we have infected domestic rabbits with a single dose of hfv and followed them at the biological and molecular levels for 5 years. no apparent pathology was detectable ... | 1997 | 9123833 |
| protein composition and morphology of human foamy virus intracellular cores and extracellular particles. | characterization of human foamy virus (hfv) gag-encoded precursors and the search for a gag-pol polyprotein and mature proteins derived from proteolytic processing were carried out in hfv-infected cells and with purified preassembled cores and extracellular virus by western blotting and radioimmunoprecipitation using antisera against synthetic peptides corresponding to putative gag and protease proteins. precursor proteins, pr78gag/74gag and pr135pol, were found in the nucleus of epithelial and ... | 1997 | 9123838 |
| generation of herpes virus saimiri-transformed t-cell lines from macaques is restricted by reactivation of simian spuma viruses. | herpes virus saimiri (hvs) transforms human t-cells in vitro to stable growth. these t-cell lines retain their immunological characteristics of the parent cells and do not release infectious virus. recently, lymphocytes of old world monkeys were efficiently transformed by hvs. in parallel to these studies we initiated transformation experiments by infecting peripheral blood cell cultures of 45 monkeys, 35 rhesus and 10 cynomolgus macaques. in only three cases, we obtained transformed t-cell line ... | 1997 | 9123851 |
| identification of sites that act together to direct dimerization of human foamy virus rna in vitro. | 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 s ... | 1997 | 9123868 |
| long terminal repeat u3 length polymorphism of human foamy virus. | 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 ... | 1997 | 9143272 |
| efficient pseudotyping of murine leukemia virus particles with chimeric human foamy virus envelope proteins. | incorporation of human foamy virus (hfv) envelope proteins into murine leukemia virus (mulv) particles was studied in a transient transfection packaging cell system. we report here that wild-type hfv envelope protein can pseudotype mulv particles, albeit at low efficiency. complete or partial removal of the hfv cytoplasmic tail resulted in an abolishment or reduction of hfv-mediated infectivity, implicating a role of the hfv envelope cytoplasmic tail in the pseudotyping of mulv particles. mutati ... | 1997 | 9151877 |
| simian foamy virus isolated from an accidentally infected human individual. | evidence for natural foamy virus (fv) infections in humans is still lacking. however, accidental infections of humans with simian fv have been demonstrated by serology and pcr, but all previous attempts to recover infectious virus in such cases have failed. here we describe the isolation of a simian fv from peripheral blood mononuclear cells (pbmc) of a healthy animal caretaker, who acquired the virus 20 years ago from an african green monkey (agm) bite. properties of the human isolate such as h ... | 1997 | 9151878 |
| replication of feline syncytial virus in feline t-lymphoblastoid cells and induction of apoptosis in the cells. | feline syncytial virus (fsv) was isolated from feline peripheral blood mononuclear cells of fsv-seropositive cats. when the susceptibility of feline t-lymphocytes to fsv was examined using three strains of fsv, fsv antigens were detected in the fsv-infected t-lymphoblastoid cells. further, a diversity of biological properties, including replication kinetics and syncytia formation, was noted among the strains, and condensation of chromatin and the fragmentation of cellular dna were observed in th ... | 1997 | 9194043 |
| suppression of retrovirial replication: inactivation of murine leukemia virus by compounds reacting with the zinc finger in the viral nucleocapsid protein. | all retroviral nucleocapsid (nc) proteins, except those of spumaretroviruses, contain one or two zinc fingers, consisting of the sequence c-x2-c-x4-h-x4-c. rice et al. (science 270:1194-1197, 1995) have described a series of compounds which inactivate hiv-1 particles and oxidize the sulfur atoms in the nc zinc finger. we have characterized the effects of three such compounds on moloney murine leukemia virus (mulv). we find that, as with hiv-1, the compounds inactivate cell-free mulv particles an ... | 1997 | 9209313 |
| sensitization of rhabdo-, lenti-, and spumaviruses to human serum by galactosyl(alpha1-3)galactosylation. | vesicular stomatitis virus, human immunodeficiency virus type 2, and human foamy virus, which were produced by cell lines expressing galactosyl(alpha1-3)galactosyl (alphagal) sugars, were found to be less stable in human serum than those from alphagal-negative cells, indicating that galactosyl(alpha1-3)galactosylation sensitizes these viruses as well as mammalian type c oncoviruses (rother et al., j. exp. med. 182:1345-1355, 1995; takeuchi et al., nature (london) 379:85-88, 1996) to complement k ... | 1997 | 9223512 |
| non-random deletions in human foamy virus long terminal repeat during viral infection. | we have characterized a new form of human foamy virus (hfv) non-random deleted long terminal repeat (ltr) sizing 1078-bp, deleted in its u3 region, sensitive to the viral transactivator and functional in an infectious proviral clone. besides two known hfv ltrs of 1260-bp and 1123-bp, this ltr represents the smallest, designed s. analysis of the ltr sequence shows the presence of short direct repeats surrounding the deletions, suggesting a mechanism generating deletion by misalignment of the grow ... | 1997 | 9229011 |
| characterization of the genome of feline foamy virus and its proteins shows distinct features different from those of primate spumaviruses. | 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 s ... | 1997 | 9261397 |
| mouse model to study the replication of primate foamy viruses. | a mouse model was developed to study the virus-host interaction of molecularly cloned human foamy virus (hfv) in vivo. the infectious process was analysed in two mouse strains, cba/ca and c57bl/6j, over a period of 24 weeks by pcr on dnas from various animal tissues; virus serology was examined by immunoblotting. the infection persisted in both mouse strains and did not induce clinical symptoms. upon infection of adult cba/ca mice hfv became detectable by pcr in an increasing number of organs ov ... | 1997 | 9266990 |
| simian foamy virus type 1 (sfv-1) induces apoptosis. | foamy virus infection causes cytopathology in several cell types from different species. the mechanism of cell killing by foamy viruses is not known. in this report, the mechanism of cell death induced by simian foamy virus type 1 (sfv-1) infection was investigated in fibroblast and lymphoid derived cells lines. infected l-929 (fibroblast) and raji (b cell) cells showed chromatin condensation, chromatin cleavage into nucleosome oligomers, and ultrastructural changes consistent with apoptosis. th ... | 1997 | 9282778 |
| expression and molecular characterization of an enzymatically active recombinant human spumaretrovirus protease. | 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 re ... | 1997 | 9299401 |
| gene transfer using replication-defective human foamy virus vectors. | 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 prov ... | 1997 | 9300037 |
| human foamy virus reverse transcription that occurs late in the viral replication cycle. | foamy viruses (fvs) are retroid viruses which use a replication strategy unlike those of other retroviruses and hepadnaviruses (s. f. yu, d. n. baldwin, s. r. gwynn, s. yendapilli, and m. l. linial, science 271:1579-1582, 1996). one of the striking differences between fvs and retroviruses is the presence of large amounts of linear genome-length dna in fv-infected cells and in virions. we report here that large quantities of genome-length linear fv dna accumulate in cells infected with fv, as det ... | 1997 | 9311807 |
| carboxy-terminal cleavage of the human foamy virus gag precursor molecule is an essential step in the viral life cycle. | foamy viruses (fvs) express the gag protein as a precursor with a molecular mass of 74 kda (pr74) from which a 70-kda protein (p70) is cleaved by the viral protease. to gain a better understanding of fv gag protein processing and function, we have generated and analyzed mutants in the c-terminal gag region of an infectious molecular clone. our results show that p70 is an n-terminal cleavage product of pr74. however, we were unable to identify a p4 molecule. a virus mutant expressing p70 only was ... | 1997 | 9311808 |
| a rapid streptavidin-capture elisa specific for the detection of antibodies to feline foamy virus. | we report a simple procedure for the rapid development of an elisa with the potential for wide application to any defined protein antigen. the procedure involves the expression of protein encoded by a pcr product, using a commercially available t-vector that adds a biotin tag, and a single step purification by affinity for streptavidin for direct use in elisa. in our experiments, a recombinant protein from the nucleocapsid domain of the feline foamy virus gag gene was expressed as a fusion prote ... | 1997 | 9328588 |
| comparison of the complete sequence of feline spumavirus with those of the primate spumaviruses reveals a shorter gag gene. | the complete nucleotide sequence of the provirus of feline foamy virus (fefv), strain f-17, was determined, and compared to the available data for human and simian spumaviruses. in addition to the usual retroviral gag, pol and env genes, two open reading frames are present between the env gene and the 3'-ltr, as in the simian spumaviruses, the first being the putative transactivator. the gag gene is predicted to encode a precursor protein of only 53 kda compared to 70 kda for simian spumaviruses ... | 1997 | 9349476 |
| seroprevalence of bartonella henselae infection and correlation with disease status in cats in switzerland. | the prevalence of infection with bartonella henselae was investigated in cats from different areas of switzerland. serum samples of 728 cats were examined for antibodies to b. henselae by immunofluorescent antibody testing, and the results were analyzed with a view to a possible correlation between a positive titer and signalment, clinical signs, infection with feline leukemia virus (felv), feline immunodeficiency virus (fiv), feline coronavirus (fcov), or feline spumavirus (fesfv), and the livi ... | 1997 | 9350752 |
| deletion analysis of both the long terminal repeat and the internal promoters of the human foamy virus. | deletion analyses of the long terminal repeat (ltr) and internal promoters (ip) of human foamy virus (hfv) showed that a negative acting element resides in the u5 region of the 5' ltr reducing reporter gene expression tenfold. the basal activity of the ip was higher than that obtained with ltr promoter constructs and strongly elevated in permissive bhk-21 cells whereas semi-permissive cos-7 cells showed low basal activity. since the basal activity of the ip is critical for initiating hfv gene ex ... | 1997 | 9354264 |
| characterization of new simian foamy viruses from african nonhuman primates. | simian foamy viruses (sfv) are exogenous retroviruses present in most if not all nonhuman primate species. baboons and other african monkey species are known to harbor sfvs, yet there is presently no data in regard to their genetic relationship. here we studied sfvs from baboons as compared to other sfvs isolated from a hamlyn's guenon, a patas monkey, and a vervet. by western blot analysis, the gag precursor proteins (p74/p70) were detected from all sfvs. in addition, the envelope glycoproteins ... | 1997 | 9356346 |
| regulation of gene expression by human foamy virus and potentials of foamy viral vectors. | the hallmarks of the spumaretrovirus or human foamy virus (hfv) are summarized and discussed with special focus on the potentials to use hfv as a new retroviral vector system. the special features of hfv are the expression of pol by splicing and start of translation at a defined initiation codon. the first met of pol is conserved in the six known foamy virus genomic sequences. another remarkable characteristic of hfv is the presence of a gly-arg-rich sequence instead of the cys-cys motif of the ... | 1997 | 9368334 |
| identification and functional characterization of a high-affinity bel-1 dna binding site located in the human foamy virus internal promoter. | the transcription of genes carried by primate foamy viruses is dependent on two distinct promoter elements. these are the long terminal repeat (ltr) promoter, which regulates expression of the viral structural proteins, and a second internal promoter, located towards the 3' end of the env gene, that directs expression of the viral auxiliary proteins. one of these auxiliary proteins is a potent transcriptional transactivator, termed bel-1 in human foamy virus (hfv) and tas or taf in the related s ... | 1998 | 9420252 |
| characterization of provirus clones of simian foamy virus type 1. | 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 r ... | 1998 | 9420293 |
| foamy virus vectors for suicide gene therapy. | to improve the delivery of so-called suicide genes into tumors, recombinant retroviruses were constructed by inserting the herpes virus type 1 (hsv-1) thymidine kinase (tk), the e. coli cytosine deaminase (cd) and polynucleoside phosphorylase (pnp), or the jellyfish gene for the green fluorescent protein (gfp) into a foamy virus (fv)-derived replication-competent vector (pfov-7). expression and stability of the inserted foreign gene was analyzed by immunoblot and polymerase chain reaction (pcr). ... | 1997 | 9425452 |
| foamy virus particle formation. | subgenomic expression plasmids for the so-called human foamy virus (hfv) structural gag, gag/pol, and env genes were constructed and used to analyze foamy virus particle formation by electron microscopy. expression of an r-u5-gag-pol construct under control of the human cytomegalovirus immediate-early enhancer-promoter resulted in the formation of viral cores with a homogeneous size of approximately 50 nm located in the cytoplasm. upon coexpression of an envelope construct, particles were observ ... | 1998 | 9445065 |
| the nucleotide sequence and spliced pol mrna levels of the nonprimate spumavirus bovine foamy virus. | 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 ... | 1998 | 9499074 |
| cis-acting sequences required for simian foamy virus type 1 vectors. | 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 ... | 1998 | 9525680 |
| retroviral zoonoses. | 1998 | 9546779 | |
| identification of a human population infected with simian foamy viruses. | studying the transmission of simian retroviruses to humans can help define the importance of these infections to public health. we identified a substantial prevalence (4/231, 1.8%) of infection with simian foamy viruses (sfv) among humans occupationally exposed to nonhuman primates. evidence of sfv infection included seropositivity, proviral dna detection and isolation of foamy virus. the infecting sfv originated from an african green monkey (one person) and baboons (three people). these infecti ... | 1998 | 9546784 |
| degeneration of the cerebellar granule cell layer in transgenic mice expressing genes of human foamy virus. | transgenic mice expressing various combinations of structural and regulatory genes of human foamy virus (hfv) develop a neurodegenerative syndrome. delta gpe transgenic mice (which express the auxiliary bel-1 and bet genes along with truncated forms of gag, pol, and env) develop a severe neurological syndrome consisting mainly of spastic tetraparesis and blindness, and show neuronal loss in the hippocampus and cerebral cortex. in addition, mice in two of eight delta gpe lines developed an ataxic ... | 1998 | 9549727 |
| the roles of pol and env in the assembly pathway of human foamy virus. | human foamy virus (hfv) is the prototype of the spumavirus genus of retroviruses. these viruses have a genomic organization close to that of other complex retroviruses but have similarities to hepadnaviruses such as human hepatitis b virus (hbv). both hfv and hbv express their pol protein independently of their structural proteins. retroviruses and hepadnaviruses differ in their requirements for particle assembly and genome packaging. assembly of retroviral particles containing rna genomes requi ... | 1998 | 9557646 |
| characterization of a human foamy virus 170-kilodalton env-bet fusion protein generated by alternative splicing. | primate foamy viruses (fvs) express, in addition to the 130-kda envelope protein, a 170-kda glycoprotein, which reacts with antisera specific for the envelope and bel proteins. we determined the exact nature of this 170-kda glycoprotein by using the molecularly cloned human fv (hfv). radioimmunoprecipitation analysis of 293t cells transfected with appropriate expression constructs by using antisera specific for the hfv env, bel1, and bel2 proteins, as well as reverse transcription-pcr analysis o ... | 1998 | 9557698 |
| an evolutionarily conserved splice generates a secreted env-bet fusion protein during human foamy virus infection. | foamy viruses (spumaretroviruses) represent a retroviral genus which exhibits unusual features relating it to pararetroviruses. previously, we reported the existence of a protein species harboring env, bel, and bet epitopes in human foamy virus (hfv)-infected cells (m. l. giron, f. rozain, m. c. debons-guillemin, m. canivet, j. périès, and r. emanoil-ravier, j. virol. 67:3596-3600, 1993). here, we identify this protein as a 160-kda env-bet fusion glycoprotein (gp160) translated from an mrna spec ... | 1998 | 9573257 |
| detection of subgenomic cdnas and mapping of feline foamy virus mrnas reveals complex patterns of transcription. | feline foamy virus (fefv) belongs to the group of spumaretroviruses that contain in addition to gag, pol, and env accessory genes collectively called bel genes. primate fvs have been shown to utilize internal promoters in addition to the 5' ltr promoters. in contrast to other known retroviruses, the fv pol genes are expressed via spliced transcripts. northern blot analysis and reverse transcription-coupled polymerase chain reactions (rt-pcr) were used to amplify, clone, and characterize cdnas ge ... | 1998 | 9601510 |
| derivation and functional characterization of a consensus dna binding sequence for the tas transcriptional activator of simian foamy virus type 1. | although dna binding sites specific for the bel-1 and tas transcriptional activators, encoded, respectively, by the human and simian foamy viruses, have been mutationally defined, they show little evident sequence identity. as a result, the sequence determinants for dna binding by both bel-1 and tas have remained unclear. here, we report the use of a novel in vivo randomization and selection strategy to identify a tas dna binding site consensus. this approach takes advantage of the fact that tas ... | 1998 | 9621006 |
| sequences in pol are required for transfer of human foamy virus-based vectors. | a series of vectors with heterologous genes was constructed from hsrv1, an infectious clone of human foamy virus (hfv), and transfected into baby hamster kidney cells to generate stably transfected vector cell lines. two cis-acting sequences were required to achieve efficient rescue by helper virus. the first element was located at the 5' end upstream of position 1274 of the proviral dna. interestingly, a mutation in the leader sequence which decreased the ability to dimerize in vitro inhibited ... | 1998 | 9621007 |
| cross-species infection: no news is good news? | 1998 | 9623952 | |
| characterization of a cis-acting sequence in the pol region required to transfer human foamy virus vectors. | to identify cis-acting elements in the foamy virus (fv) rna pregenome, we developed a transient-vector-production system based on cotransfection of indicator gene-bearing vector and gag-pol and env expression plasmids. two elements which were critical for vector transfer were found and mapped approximately. the first element was located in the ru5 leader and the 5' gag region (approximately up to position 650 of the viral rna). the second element was located in an approximately 2-kb sequence in ... | 1998 | 9658069 |
| amplification of simian retroviral sequences from human recipients of baboon liver transplants. | investigations into the use of baboons as organ donors for human transplant recipients, a procedure called xenotransplantation, have raised the specter of transmitting baboon viruses to humans and possibly establishing new human infectious diseases. retrospective analysis of tissues from two human transplant recipients with end-stage hepatic disease who died 70 and 27 days after the transplantation of baboon livers revealed the presence of two simian retroviruses of baboon origin, simian foamy v ... | 1998 | 9671210 |
| y;16 translocation breakpoint associated with a partial turner phenotype identifies a foamy virus insertion. | we have previously identified yacs containing the y breakpoint in a male patient with turner-like hydrops in the newborn period and a y;16 translocation (erickson et al., 1995). we have now subcloned these yacs and built a lambda contig across the y breakpoint. a subclone near the y;16 breakpoint of our patient shows great evolutionary conservation by hybridization to a zoo blot. we have sequenced the region responsible for the hybridization and found a foamy (spuma) virus sequence. these viruse ... | 1998 | 9678358 |
| the carboxy-terminal p3gag domain of the human foamy virus gag precursor is required for efficient virus infectivity. | proteolytic processing of foamy virus gag proteins appears to be different from that of other retroviruses. a single carboxy-terminal cleavage site is consistently detectable in human foamy virus (hfv) gag precursor protein p74gag derived from infected cells and/or purified virus particles. using a recombinant hfv protease, we have determined the p74gag cleavage site that results in p70gag and the carboxy-terminal p3gag (pfrepper et al., 1997, biochem. biophys. res. commun. 237, 548-553). to stu ... | 1998 | 9683566 |
| methods of gene delivery. | human gene therapy continues to be an exciting concept for the treatment of disease. this field of research remains in its early stages, but already a number of studies have provided "proof-of-principle." although there is no unequivocal evidence of efficacy, there have been demonstrated physiologic changes that are relevant to the disease process. one of the major challenges still confronting the field is the design of more efficient vectors. the gene delivery systems being used today will undo ... | 1998 | 9684094 |
| prevalence of human foamy virus-related sequences in the korean population. | the possible association of human foamy virus (hfv) with human thyroid disorders such as graves' disease (gd) has been a topic of controversy due to the inconsistent results reported by several groups of investigators. here we report the investigation of the presence of hfv-related sequences in the korean population. dna was obtained from peripheral blood lymphocytes from 24 gd patients and 23 healthy blood donors and subjected to pcr amplification using three sets of nested primers derived from ... | 1998 | 9691219 |
| molecular characterization of proteolytic processing of the pol proteins of human foamy virus reveals novel features of the viral protease. | spumaviruses, or foamy viruses, express a pol-specific transcript that codes for a pol polyprotein that consists of the protease, reverse transcriptase, ribonuclease h, and the integrase domains. to delineate the proteolytic cleavage sites between the pol subdomains, recombinant human foamy virus (hfv) pol proteins were expressed, purified by affinity chromatography, and subjected to either hfv protease assays or autocatalytic processing. in control experiments, hfv protease-deficient mutant pro ... | 1998 | 9696869 |
| detection and molecular characterisation of feline foamy virus serotypes in naturally infected cats. | 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 w ... | 1998 | 9705907 |
| latent foamy and simian retroviruses in healthy african green monkeys used in biomedical research. | 1998 | 9734894 | |
| importance of basic residues in the nucleocapsid sequence for retrovirus gag assembly and complementation rescue. | the gag proteins of rous sarcoma virus (rsv) and human immunodeficiency virus (hiv) contain small interaction (i) domains within their nucleocapsid (nc) sequences. these overlap the zinc finger motifs and function to provide the proper density to viral particles. there are two zinc fingers and at least two i domains within these gag proteins. to more thoroughly characterize the important sequence features and properties of i domains, we analyzed gag proteins that contain one or no zinc finger mo ... | 1998 | 9765448 |
| cells expressing the human foamy virus (hfv) accessory bet protein are resistant to productive hfv superinfection. | bet is a foamy virus (fv) accessory protein not required for virus replication. the function of bet is not understood. we report on the generation of cell lines stably expressing the hfv bet protein. in bet+ cells, hfv replication was reduced by approximately 3-4 orders of magnitude compared with control cells. the hfv bet-expressing cells only partially resisted infection by the distantly related feline fv (ffv). pseudotyping experiments, using murine retroviral vectors with an hfv envelope, re ... | 1998 | 9770433 |
| identification of an exogenous retrovirus (foamy virus type 1) in rhesus monkey kidney cell culture: significance to viral diagnostics. | 1998 | 9785216 | |
| nuclear localization of the functional bel 1 transactivator but not of the gag proteins of the feline foamy virus. | interactions between host cells and foamy or spumaretroviruses are different from those of other known retroviruses. previous work has suggested that the gag and high-affinity dna-binding bel 1 transactivator of human foamy virus are localized in the nuclei of infected cells. using two independent detection methods, we show here that the functionally active bel 1 transactivator protein of feline foamy virus is of nuclear localization. in contrast to that reported for the human foamy virus gag pr ... | 1998 | 9813199 |
| xenotransplantation: about baboon hearts and pig livers. | 1998 | 9846357 | |
| seroepidemiological survey of feline retrovirus infections in domestic and leopard cats in northern vietnam in 1997. | the prevalence of infections with three feline retroviruses (feline immunodeficiency virus (fiv), feline leukemia virus (felv) and feline syncytial virus (fsv)) was examined in northern vietnam in 1997. we collected a total of 77 blood samples from 69 domestic and 8 leopard cats, and examined the presence of anti-fiv and fsv antibodies and felv p27 antigen in the plasma samples by the indirect immunofluorescence and/or two commercial kits. none of the samples was positive for fiv and felv. the o ... | 1998 | 9853314 |
| helper-free foamy virus vectors. | retroviral vectors based on human foamy virus (hfv) have been developed and show promise as gene therapy vehicles. here we describe a method for the production of hfv vector stocks free of detectable helper virus. the helper and vector plasmid constructs used both lack the hfv bel genes, so recombination between these constructs cannot create a wild-type virus. a fusion promoter that combines portions of the cytomegalovirus (cmv) immediate-early and hfv long terminal repeat (ltr) promoters was u ... | 1998 | 9853518 |
| giant syncytia and virus-like particles in ovarian carcinoma cells isolated from ascites fluid. | ovarian cancer cells were isolated from ascites fluid of 30 different patients diagnosed with cystadenocarcinoma of ovaries. large colonies of malignant asc cells were observed during the first week of cell growth in vitro. colony formation was followed by fusion of cells and formation of large multinucleated and highly vacuolated syncytia. in contrast, cells isolated from the ascites fluid produced by patients with benign mucinous cystadenoma of ovaries did not form syncytia. nonmalignant brenn ... | 1999 | 9874674 |
| evidence that the human foamy virus genome is dna. | the genomes of the spumaviruses, of which human foamy virus (hfv) is the prototype, are very similar to those of other complex retroviruses. however, in some aspects of the viral replicative cycle, hfv more closely resembles pararetroviruses such as hepatitis b virus. previous work indicated that hfv extracellular particles contain apparently full-length double-stranded dna, as well as rna. we have further characterized the amount of dna in particles and the role that this dna has in viral repli ... | 1999 | 9882362 |
| gamma interferon is a major suppressive factor produced by activated human peripheral blood lymphocytes that is able to inhibit foamy virus-induced cytopathic effects. | the activation of human peripheral blood lymphocytes by mitogens or by triggering the t-cell receptor with anti-cd3 antibodies leads to the production of a potent soluble inhibitory activity against foamy virus-induced cytopathic effects in vitro. the inhibitory activity acts in a species-specific manner. as a consequence, the isolation of foamy viruses from blood lymphocytes of infected humans is accelerated in a heterologous coculture system. antibodies against gamma interferon (ifn-gamma) are ... | 1999 | 9882388 |
| study of human foamy virus proviral integration in chronically infected murine cells. | this report describes integration sites of human foamy virus (hfv) in chronically infected balb/c murine cells that we isolated by inverse pcr and characterized. we show that integration of hfv proviral genome mainly occurs in highly repetitive and/or transcriptionally active regions and leads to the formation of a 4-bp cellular direct repeat sequence at each provirus extremity. as non-random deletions were previously described in the hfv be/1 transactivator gene as well as in the long terminal ... | 1998 | 9923015 |