bpv1 e2 protein enhances packaging of full-length plasmid dna in bpv1 pseudovirions.we studied determinants of efficient encapsidation of circular dna, incorporating a pv early region dna sequence (nt 584-1978) previously shown to enhance packaging of dna within papillomavirus (pv)-like particles (vlps). insect coelomic cells (sf-9) and cultured monkey kidney cells (cos-1) were transfected with an 8-kb reporter plasmid incorporating the putative bpv packaging sequence and infected with bpv1 l1 and l2 recombinant baculovirus or vaccinia virus. heavy (1.34 g/ml) and light (1.30 g ...200010873782
papillomavirus virus-like particles for the delivery of multiple cytotoxic t cell epitopes.chimeric papillomavirus (pv) virus-like particles (vlps) based on the bovine papillomavirus type 1 (bpv-1) l1 protein were constructed by replacing the 23-carboxyl-terminal amino acids of the bpv1 major protein l1 with an artificial "polytope" minigene, containing known ctl epitopes of human pv16 e7 protein, hiv iiib gp120 p18, nef, and reverse transcriptase (rt) proteins, and an hpv16 e7 linear b epitope. the ctl epitopes were restricted by three different mhc class i alleles (h-2(b), h-2(d), h ...200010915608
crystal structure of the dna binding domain of the replication initiation protein e1 from papillomavirus.papillomaviral infection causes both benign and malignant lesions and is a necessary cause of cervical carcinoma. replication of this virus requires the replication initiation proteins e1 and e2, which bind cooperatively at the origin of replication (ori) as an (e1)2-(e2)2-dna complex. this is a precursor to larger e1 complexes that distort and unwind the ori. we present the crystal structure of the e1 dna binding domain refined to 1.9 a resolution. residues critical for dna binding are located ...200010949036
episomal vectors for gene expression in mammalian important reason for preferring mammalian cells for heterologous gene expression is their ability to make authentic proteins containing post-translational modifications similar to those of the native protein. the development of expression systems for mammalian cells has been ongoing for several years, resulting in a wide variety of effective expression vectors. the aim of this review is to highlight episomal expression vectors. such episomal plasmids are usually based on sequences from dna vi ...200010971576
the platelet-derived growth factor beta receptor as a target of the bovine papillomavirus e5 protein.the 44-amino acid e5 protein of bovine papillomavirus is a homo-dimeric, transmembrane protein that transforms cells by activating the platelet-derived growth factor ss receptor in a ligand-independent fashion. the e5 protein induces receptor activation by forming a stable complex with the receptor, thereby inducing receptor dimerization, trans-phosphorylation of tyrosine residues in the cytoplasmic domain of the receptor, and recruitment of cellular sh2 domain-containing proteins into a signal ...200010959076
e2f-rb complexes assemble and inhibit cdc25a transcription in cervical carcinoma cells following repression of human papillomavirus oncogene expression.expression of the bovine papillomavirus e2 protein in cervical carcinoma cells represses expression of integrated human papillomavirus (hpv) e6/e7 oncogenes, followed by repression of the cdc25a gene and other cellular genes required for cell cycle progression, resulting in dramatic growth arrest. to explore the mechanism of repression of cell cycle genes in cervical carcinoma cells following e6/e7 repression, we analyzed regulation of the cdc25a promoter, which contains two consensus e2f bindin ...200010982822
sumo-1 modification of bovine papillomavirus e1 protein is required for intranuclear accumulation.the e1 protein is a multifunctional, origin-binding helicase that is essential for replication of papillomaviruses. recently, bovine papillomavirus e1 was shown to be post-translationally modified by the addition of the sumo-1 polypeptide. here we show that the site of sumoylation maps to lysine residue 514. this lysine and the flanking sequences are well conserved in human papillomavirus (hpv) e1 proteins. both hpv1a and hpv18 e1 proteins are substrates for sumoylation in vitro, which is consis ...200011005821
interaction of the papillomavirus transcription/replication factor, e2, and the viral capsid protein, l2.the minor capsid protein l2 of papillomaviruses (pvs) likely plays a role in the selective encapsidation of pv dna in viral capsids and in the infectivity of pv virions. the l2 protein also can cause the relocalization of the pv early protein, e2ta, to nuclear subdomains known as promyelocytic leukemia oncogenic domains (pods) in which it is localized. e2ta is a transcriptional transactivator that also plays a critical role in viral dna replication. in this study, we investigated whether l2, in ...200011040122
interaction with cbp/p300 enables the bovine papillomavirus type 1 e6 oncoprotein to downregulate cbp/p300-mediated transactivation by p53.the e6 oncoprotein of bovine papillomavirus type 1 (bpv-1) can transform cells independently of p53 degradation. the precise mechanisms underlying this transformation are not yet completely understood. here it is shown that bpv-1 e6 interacts with cbp/p300 in the same way as described for the e6 proteins of oncogenic human papillomaviruses. this interaction results in an inhibition of the transcriptional coactivator function of cbp/p300 required by p53 and probably by other transcription factors ...200011038372
utilization of the bovine papillomavirus type 1 late-stage-specific nucleotide 3605 3' splice site is modulated by a novel exonic bipartite regulator but not by an intronic purine-rich element.bovine papillomavirus type 1 (bpv-1) late gene expression is regulated at both transcriptional and posttranscriptional levels. maturation of the capsid protein (l1) pre-mrna requires a switch in 3' splice site utilization. this switch involves activation of the nucleotide (nt) 3605 3' splice site, which is utilized only in fully differentiated keratinocytes during late stages of the virus life cycle. our previous studies of the mechanisms that regulate bpv-1 alternative splicing identified three ...200011044105
repression of human papillomavirus oncogenes in hela cervical carcinoma cells causes the orderly reactivation of dormant tumor suppressor pathways.most cervical carcinomas express high-risk human papillomaviruses (hpvs) e6 and e7 proteins, which neutralize cellular tumor suppressor function. to determine the consequences of removing the e6 and e7 proteins from cervical cancer cells, we infected hela cells, a cervical carcinoma cell line that contains hpv18 dna, with a recombinant virus that expresses the bovine papillomavirus e2 protein. expression of the e2 protein resulted in rapid repression of hpv e6 and e7 expression, followed approxi ...200011070078
distinctive cognate sequence discrimination, bound dna conformation, and binding modes in the e2 c-terminal domains from prototype human and bovine papillomaviruses.the c-terminal dna binding domain of the e2 protein is involved in transcriptional regulation and dna replication in papillomaviruses. at low ionic strength, the domain has a tendency to form aggregates, a process readily reversible by the addition of salt. while fluorescence anisotropy measurements show a 1:1 stoichiometry at ph 5.5, we observed that a second hpv-16 e2 c-terminal dimer can bind per dna site at ph 7.0. this was confirmed by displacement of bis-ans binding, tryptophan fluorescenc ...200011087426
the e1 initiator recognizes multiple overlapping sites in the papillomavirus origin of dna replication.a common feature of replicator sequences from a variety of organisms is multiple binding sites for an initiator protein. by binding to the replicator, initiators mark the site and contribute to melting or distortion of the dna. we have defined the recognition sequence for the papillomavirus e1 initiator and determined the arrangement of binding sites in the viral origin of replication. we show that e1 recognizes a hexanucleotide sequence which is present in overlapping arrays in virtually all pa ...200111119599
effect of bpv1 e2-mediated inhibition of e6/e7 expression in hpv16-positive cervical carcinoma cells.e6 and e7 proteins of high-risk-type human papillomavirus are major etiological agents for cervical carcinomas and are continuously expressed in those cancer cells. they inhibit cell cycle control functions by inactivating p53 and rb proteins and also immortalize cells through the induction of telomerase activity. expression of e6 and e7 genes in hela, an hpv18-positive cell line, has been shown to be inhibited by the e2 protein of bovine papillomavirus (bpv1), and this resulted in the activatio ...200111161855
solution structure determination and mutational analysis of the papillomavirus e6 interacting peptide of e6ap.e6ap is a cellular protein that binds cancer-related papillomaviral e6 proteins. the e6 binding domain, called e6ap, is located on an 18-amino acid segment of e6ap. the corresponding peptide was synthesized and its structure determined by nuclear magnetic resonance spectroscopy. the overall structure of the peptide is helical. a consensus e6-binding sequence among different e6 interacting proteins contains three conserved hydrophobic residues. in the structure of the e6ap peptide, the three cons ...200111170455
l1 interaction domains of papillomavirus l2 necessary for viral genome encapsidation.bphe-1 cells, which harbor 50 to 200 viral episomes, encapsidate viral genome and generate infectious bovine papillomavirus type 1 (bpv1) upon coexpression of capsid proteins l1 and l2 of bpv1, but not coexpression of bpv1 l1 and human papillomavirus type 16 (hpv16) l2. bpv1 l2 bound in vitro via its c-terminal 85 residues to purified l1 capsomers, but not with intact l1 virus-like particles in vitro. however, when the efficiency of bpv1 l1 coimmunoprecipitation with a series of bpv1 l2 deletion ...200111287582
the pagetoid variant of urothelial carcinoma in situ of urinary bladder in a cow.a case of urothelial carcinoma in situ of urinary bladder is reported in a 10-year-old cow naturally grazing on bracken-infested land. the cow suffered from enzootic hematuria for more than 5 years. the presence of bovine papillomavirus type 2 (bpv-2) dna sequences was detected by polymerase chain reaction. the carcinoma in situ was characterized by the presence of anaplastic cells with amphophilic cytoplasm and pleomorphic nuclei containing granular, irregularly dispersed chromatin. focal areas ...200111199158
a novel silencer element in the bovine papillomavirus type 4 promoter represses the transcriptional response to papillomavirus e2 protein.the long control regions (lcrs) of mucosal epitheliotropic papillomaviruses have similar organizations: a promoter region, an enhancer region, and a highly conserved distribution of e2 dna binding sites (c. desaintes and c. demeret, semin. cancer biol. 7:339--347, 1996). the enhancer of these viruses is epithelial cell specific, as it fails to activate transcription from heterologous promoters in nonepithelial cell types (b. gloss, h. u. bernard, k. seedorf, and g. klock, embo j. 6:3735--3743, 1 ...200111222708
xenograft model for identifying chemotherapeutic agents against papillomaviruses.the report describes the establishment and characterization of a mouse xenograft transplantation model for the study of papillomavirus infection of bovine skin. calf scrotal skin was inoculated with bovine papillomavirus type 2 before grafting it to the dorsum of severe combined immunodeficient mice. the grafted skin contained epidermis, dermis, and a thin layer of fat. after 5 months the induced warts not only showed histological features of papillomavirus infections but also tested positive fo ...200111257010
association of bovine papillomavirus type 1 with microtubules.transport of bpv-1 virus from the cell membrane to the nucleus was studied in vitro in cv-1 cells. at reduced temperature (4 degrees c), bpv-1 binding to cv-1 cells was unaffected but there was no transport of virions across the cytosol. electron microscopy showed bpv-1 virions in association with microtubules in the cytoplasm, a finding confirmed by co-immunoprecipitation of l1 protein and tubulin. internalization of virus was unimpaired in cells treated with the microtubule-depolymerizing drug ...200111289806
mechanism and requirements for bovine papillomavirus, type 1, e1 initiator complex assembly promoted by the e2 transcription factor bound to distal sites.dna replication of papillomavirus requires the viral initiator e1 and the transcription factor e2. bovine papillomavirus, type 1 (bpv-1), e1, and e2 bind cooperatively as dimers to proximal sites in the viral replicator generating a sequence-specific e1e2-ori complex. this complex is critical for replication and can be converted to a multimeric e1-ori initiator complex by displacement of e2 in the presence of hydrolyzable atp. however, e2 can function over extended distances, and e2 at a distal ...200111323428
replication of a chimeric origin containing elements from epstein-barr virus ori p and bovine papillomavirus minimal origin.the bovine papillomavirus e2 protein is a multifunctional protein that activates viral transcription, co-operates in initiation of viral dna replication, and is required for long-term episomal maintenance of viral genomes. the ebna1 protein of epstein-barr virus is required for synthesis and maintenance of epstein-barr virus genomes. both viral proteins act through direct interactions with their respective dna sequences in their origins of replication. the chimeric protein e2:ebna1, which consis ...200111311423
papillomavirus-like particles induce acute activation of dendritic cells.the role of viral structural proteins in the initiation of adaptive immune responses is poorly understood. to address this issue, we focused on the effect of noninfectious papillomavirus-like particles (vlps) on dendritic cell (dc) activation. we found that murine bone marrow-derived dendritic cells (bmdcs) effectively bound and rapidly internalized bovine papillomavirus vlps: exposure to fully assembled vlps of bovine papillomavirus, human papillomavirus (hpv)16 or hpv18, but not to predominate ...200111313370
in vitro prediction of carcinogenicity using a bovine papillomavirus dna--carrying c3h/10t 1/2 cell line (t1). ii: results from the testing of 100 chemicals.a new in vitro test for identifying carcinogens is evaluated against a testing database of 100 chemicals including the following groups: steroids, antineoplastics, pcbs, dioxins, alkyl halides, aromatic amines, nitrogen heterocycles, polyaromatic hydrocarbons, mustards, and benzodioxoles. the assay uses focus formation in a stable, bpv-1-dna-carrying c3h/10t 1/2 mouse embryo fibroblast cell line (t1), which does not require transfection, infection with virus, or isolation of primary cells from a ...200111317341
roles of the hinge region and the dna binding domain of the bovine papillomavirus type 1 e2 protein in initiation of dna replication.the bovine papillomavirus (bpv-1) e2 protein is the regulator of extrachromosomal replication of papillomaviruses. the mutants with c-terminal truncations and in-frame internal deletions were constructed to study the role of structural domains of e2 in the initiation of dna replication. we show that the replication initiation function of e2 is absolutely dependent on the ability of the protein to bind to dna. our study also confirms the borders of the functional domains of the e2 protein; residu ...200111325464
bovine papillomavirus dna in neoplastic and nonneoplastic tissues obtained from horses with and without sarcoids in the western united determine the incidence of bovine papillomavirus (bpv) type 1 or 2 in sarcoids and other samples of cutaneous tissues collected from horses in the western united states.200111341396
pcr detection of bovine papilloma virus dna in superficial swabs and scrapings from equine sarcoids.the purpose of this study was to examine if bovine papilloma virus (bpv) dna can be detected in superficial swabs or scrapings from equine sarcoids. samples were obtained from 92 sarcoids and 20 non-sarcoidal control lesions. the polymerase chain reaction technique was used with a first primer set to check whether dna extraction was successful, and with a second primer set specific for bpv-dna. dna isolation was successful in 88% of the swabs and 93% of the scrapings. all control lesions were ne ...200111352485
quercetin, e7 and p53 in papillomavirus oncogenic cell transformation.bovine papillomavirus type 4 (bpv-4) infects the upper alimentary canal of cattle causing benign papillomas which can progress to squamous carcinomas in cattle grazing on bracken fern (bf). we have previously shown that quercetin, a well characterized and potent mutagen found in bf, causes cell cycle arrest of primary bovine cells (palf), but that a single exposure to quercetin can cause full oncogenic transformation of palf cells partially transformed by bpv-4. here we show that cell cycle arre ...200111408351
cell transformation by the e5/e8 protein of bovine papillomavirus type 4. p27(kip1), elevated through increased protein synthesis is sequestered by cyclin d1-cdk4 complexes.the e5/e8 hydrophobic protein of bpv-4 is, at only 42 residues, the smallest transforming protein identified to date. transformation of nih-3t3 cells by e5/e8 correlates with up-regulation of both cyclin a-associated kinase activity and, unusually, p27(kip1) (p27) but does not rely on changes in cyclin e or cyclin e-cdk2 activity. here we have examined how p27 is prevented from functioning efficiently as a cdk2 inhibitor, and we investigated the mechanisms used to achieve elevated p27 expression ...200111448948
positively charged termini of the l2 minor capsid protein are necessary for papillomavirus infection.coexpression of bovine papillomavirus l1 with l2 mutants lacking either eight n-terminal or nine c-terminal amino acids that encode positively charged domains resulted in wild-type levels of viral genome encapsidation. despite wild-type binding to the cell surface, the resulting virions were noninfectious. an l2 mutant encoding a scrambled version of the nine c-terminal residues restored infectivity, in contrast to an l2 mutant encoding a scrambled version of the n-terminal residues.200111581419
expression of a transforming gene (e5) of bovine papillomavirus in sarcoids obtained from determine expression of a transforming gene (e5) of bovine papillomavirus in sarcoids, other tumors, and normal skin samples collected from horses with and without sarcoids.200111497440
efficiency of delivery of dna to cells by bovine papillomavirus type-1 l1/l2 investigate the efficiency of encapsidation of plasmid by papillomavirus virus-like particles (pv vlps), and the infectivity of the resultant pv pseudovirions, cos-1 cells were transfected with an 8-kb plasmid incorporating a green fluorescent protein (gfp) reporter gene (pgsv), and infected with bovine pv (bpv-1) l1/l2 recombinant vaccinia virus to produce bpv1 pseudovirions. approximately 1 in 1.5 x 10(4) of dense (1.35 g/ml) pv pseudovirions and 0.3 in 10(4) of less-dense (1.29 g/ml) pseud ...200111499923
polymerase chain reaction analysis of the surgical margins of equine sarcoids for bovine papilloma virus examine apparently normal skin around equine sarcoids for evidence of bovine papilloma virus (bpv) dna, and to relate this finding to the observed recurrence after surgery.200111555822
chimeric papillomavirus-like particles expressing a foreign epitope on capsid surface loops.neutralization capsid epitopes are important determinants for antibody-mediated immune protection against papillomavirus (pv) infection and induced disease. chimeric l1 major capsid proteins of the human pv type 16 (hpv-16) and the bovine pv type 1 (bpv-1) with a foreign peptide incorporated into several capsid surface loops self-assembled into pentamers or virus-like particles (vlp). binding patterns of neutralizing monoclonal antibodies (mab) and immunization of mice confirmed (i) that regions ...200111602792
papillomavirus microbicidal activities of high-molecular-weight cellulose sulfate, dextran sulfate, and polystyrene sulfonate.the high-molecular-weight sulfated or sulfonated polysaccharides or polymers cellulose sulfate, dextran sulfate, and polystyrene sulfonate were tested for microbicidal activity against bovine papillomavirus type 1 (bpv-1) and human papillomavirus type 11 (hpv-11) and type 40 (hpv-40). in vitro assays included the bpv-1-induced focus-forming assay and transient infection of human a431 cells with hpvs. the compounds were tested for microbicidal activity directly by preincubation with virus prior t ...200111709319
functional mapping of the dna binding domain of bovine papillomavirus e1 protein.bovine papillomavirus type 1 (bpv-1) requires viral proteins e1 and e2 for efficient dna replication in host cells. e1 functions at the bpv origin as an atp-dependent helicase during replication initiation. previously, we used alanine mutagenesis to identify two hydrophilic regions of the e1 dna binding domain (e1dbd), hr1 (e1(179-191)) and hr3 (e1(241-252)), which are critical for sequence-specific recognition of the papillomavirus origin. based on sequence and structure, these regions are simi ...200111711585
efficient transfection of novel bovine papillomavirus 1 expression plasmids.a series of novel bovine papillomavirus type 1 (bpv-1)-based expression plasmids was constructed and characterized in vitro as a starting point for the development of an in vivo gene therapeutic method. the order of transfection efficiency for different pbpvlacz plasmids was pcgalbpv > ptkbpv > psralphabpv in cv1-p cells. in the absence of selection pressure, the expression of pcgalbpvlacz and ptkbpvlacz was associated with long-term maintenance. in a comparison of pbpvlacz with psvlacz, express ...200111735366
mechanisms of cell transformation by papillomavirus e5 proteins.the papillomavirus e5 proteins are short, hydrophobic transforming proteins. the transmembrane e5 protein encoded by bovine papillomavirus transforms cells by activating the platelet-derived growth factor beta receptor tyrosine kinase in a ligand-independent fashion. the bovine papillomavirus e5 protein forms a stable complex with the receptor, thereby inducing receptor dimerization and activation, trans-phosphorylation, and recruitment of cellular signaling proteins to the receptor. the e5 prot ...200111753669
route of administration of chimeric bpv1 vlp determines the character of the induced immune examine the mucosal immune response to papillomavirus virus-like particles (pv-vlp), mice were immunized with vlp intrarectally (i.r.), intravaginally ( or intramuscularly (i.m.) without adjuvant. pv-vlp were assembled with chimeric bpv-1 l1 proteins incorporating sequence from hiv-1 gp120, either the v3 loop or a shorter peptide incorporating a known ctl epitope (hivp18i10). antibody specific for bpv-1 vlp and p18 peptide was detected in serum following i.m., but not i.r. or immu ...200211869359
down-regulation of mhc class i by bovine papillomavirus e5 oncoproteins.the papillomavirus e5 protein is localized in the endoplasmic reticulum (er) and golgi apparatus (ga) of the host cell. transformed bovine fibroblasts expressing bovine papillomavirus (bpv) e5 are highly vacuolated and have a much enlarged, distorted and fragmented ga. major histocompatibility complex class i (mhc i) is processed and transported to the cell surface through the ga. given the cellular localization of e5 in the ga and the morphologically abnormal ga, we investigated the expression ...200211803468
e1 protein of bovine papillomavirus 1 is not required for the maintenance of viral plasmid dna replication.derivatives of bovine papillomavirus 1 (bpv1) with temperature-sensitive and dominant-negative mutation the e1 gene were used to determine the requirement for e1 in the maintenance of viral plasmid dna replication. the abilities of these mutant bpv1 genomes to replicate as nuclear plasmids were monitored at permissive (32 degrees c) and nonpermissive (37 degrees c) temperatures in mouse c127 cells. we found that the temperature-sensitive e1 mutant bpv1 genomes replicate as nuclear plasmids as ef ...200211853393
a carboxyl-terminal serine of the bovine papillomavirus e1 protein is phosphorylated in vivo and in vitro.the e1 protein of bovine papillomavirus (bpv) plays several key roles in viral dna replication. e1 binds the viral origin, unwinds template dna at the replication fork and recruits cellular replication machinery to the viral dna. e1 is phosphorylated at multiple sites, and phosphorylation of e1 regulates e1 function and viral dna replication. a consensus motif for the cellular kinase ck2 was identified at serine 584 near the carboxyl terminus of bpv e1, and found to be highly conserved among pap ...200211864754
replication of bovine papillomavirus type 1 (bpv-1) dna in saccharomyces cerevisiae following infection with bpv-1 virions.saccharomyces cerevisiae protoplasts exposed to bovine papillomavirus type 1 (bpv-1) virions demonstrated uptake of virions on electron microscopy. s. cerevisiae cells looked larger after exposure to bpv-1 virions, and cell wall regeneration was delayed. southern blot hybridization of hirt dna from cells exposed to bpv-1 virions demonstrated bpv-1 dna, which could be detected over 80 days of culture and at least 13 rounds of division. two-dimensional gel analysis of hirt dna showed replicative i ...200211884561
e1 protein of bovine papillomavirus type 1 interferes with e2 protein-mediated tethering of the viral dna to mitotic chromosomes.eukaryotic viruses can maintain latency in dividing cells as extrachromosomal plasmids. it is therefore of vital importance for viruses to ensure nuclear retention and proper segregation of their viral dna. the bovine papillomavirus (bpv) e2 enhancer protein plays a key role in these processes by tethering the viral dna to the host cell chromosomes. viral genomes that harbor phosphorylation mutations in the e2 gene are transformation defective, and for these mutant genomes, neither the viral dna ...200211884568
a bovine papilloma virus vector with a dominant resistance marker replicates extrachromosomally in mouse and e. coli cells.we describe the construction of a bovine papilloma virus-based vector (pcgbpv9) which contains a dominant selectable marker and replicates autonomously in both mouse and escherichia coli cells. this vector contains the complete bovine papilloma virus genome, a cole1 replication origin and a dominant selectable marker conferring resistance to kanamycin in bacteria and g418 in eukaryotic cells. a high number of g418r colonies are obtained after transfer of pcgbpv9 into mouse c127 cells. these g418 ...198311892800
crystal structures of two intermediates in the assembly of the papillomavirus replication initiation complex.initiation of dna replication of the papillomavirus genome is a multi-step process involving the sequential loading of viral e1 protein subunits onto the origin of replication. here we have captured structural snapshots of two sequential steps in the assembly process. initially, an e1 dimer binds to adjacent major grooves on one face of the double helix; a second dimer then binds to another face of the helix. each e1 monomer has two dna-binding modules: a dna-binding loop, which binds to one dna ...200211889054
a bovine papillomavirus-1 based vector restores the function of the low-density lipoprotein receptor in the receptor-deficient cho-ldla7 cell line.the rationale of using bovine papillomavirus-1 (bpv-1) derived vectors in gene therapy protocols lies in their episomal maintenance at intermediate to high copy number, and stable, high-level expression of the gene products. we constructed the bpv-1 based vector harbouring the human low-density lipoprotein receptor (ldlr) gene cdna and tested its ability to restore the function of the ldlr in the receptor-deficient cell line cho-ldla7.200211967145
induction of the bovine papillomavirus origin "onion skin"-type dna replication at high e1 protein concentrations in vivo.we have studied the replication of plasmids composed of bovine papillomavirus type 1 (bpv1) origin of replication and expression cartridges for viral proteins e1 and e2 in hamster and mouse cells. we found that the replication mode changed dramatically at different expression levels of the e1 protein. at high levels of the e1 protein, overreplication of the origin region of the plasmid was observed. analysis of the replication products by one-dimensional and two-dimensional gel electrophoresis s ...200211992014
hydrophobic residue contributions to sequence-specific dna binding by the bovine papillomavirus helicase e1.previously, mutational analyses of the dna binding domain of the bovine papillomavirus e1 protein (e1dbd) identified several hydrophobic residues that are critical for dna binding activity (m. west, d. flanery, k. woytek, d. rangasamy, and v. g. wilson, 2001, j. virol. 75, 11948-11960). hydrophobic interactions of nonpolar amino acid side chains can contribute to the function of dna binding proteins through both conformational effects and direct interaction with nucleotides. to further investiga ...200212036317
bovine papillomavirus type 1 e6-induced sensitization to apoptosis is distinct from its transforming activity.the bovine papillomavirus type 1 (bpv-1) e6 oncoprotein induces tumorigenic transformation of murine c127 cells and stimulates transcription when targeted to a promoter. we have previously shown that c127 cells expressing bpv-1 e6 exhibited increased tumor necrosis factor alpha (tnf)-mediated apoptosis. to understand the mechanisms by which bpv-1 e6 sensitizes cells to apoptosis and to investigate the relevance of e6-enhanced apoptosis to its other biological activities, we analyzed a bpv-1 e6 m ...200212033781
a bovine papillomavirus-1 based vector restores the function of the low-density lipoprotein receptor in the receptor-deficient cho-ldla7 cell line: correction. 200212060487
papillomavirus e1 proteins: form, function, and features.the e1 proteins are the essential origin recognition proteins for papillomavirus (pv) replication. e1 proteins bind to specific dna elements in the viral origin of replication and assemble into hexameric helicases with the aid of a second viral protein, e2. the resultant helicase complex initiates origin dna unwinding to provide the template for subsequent syntheses of progeny dna. in addition to atp-dependent helicase activity, e1 proteins interact with and recruit several host cell replication ...200212086149
efficient ectopic gene expression targeting chick mesoderm.the chick model has been instrumental in illuminating genes that regulate early vertebrate development and pattern formation. targeted ectopic gene expression is critical to dissect further the complicated gene interactions that are involved. in an effort to develop a consistent method to ectopically introduce and focally express genes in chick mesoderm, we evaluated and optimized several gene delivery methods, including implantation of 293 cells laden with viral vectors, direct adenoviral injec ...200212112459
[immunogenicity study of hpv 6b virus-like particles].to confirm human papillomavirus (hpv) 6b virus-like particles (vlp) have strong immunogenicity and the protective antibody induced by hpv 6b vlp have cross-reactive immunity against hpv11 vlp and bovine papillomavirus (bpv) 1 vlp.200212133476
multiple transmembrane amino acid requirements suggest a highly specific interaction between the bovine papillomavirus e5 oncoprotein and the platelet-derived growth factor beta receptor.the bovine papillomavirus e5 protein activates the cellular platelet-derived growth factor beta receptor (pdgfbetar) tyrosine kinase in a ligand-independent manner. evidence suggests that the small transmembrane e5 protein homodimerizes and physically interacts with the transmembrane domain of the pdgfbetar, thereby inducing constitutive dimerization and activation of this receptor. amino acids in the receptor previously found to be required for the pdgfbetar-e5 interaction are a transmembrane t ...200212134002
sequential and ordered assembly of e1 initiator complexes on the papillomavirus origin of dna replication generates progressive structural changes related to melting.multiple binding sites for an initiator protein are a common feature of replicator sequences from various organisms. by binding to the replicator, initiators mark the site and contribute to melting or distortion of the dna by largely unknown mechanisms. here we analyze origin of dna replication (ori) binding by the e1 initiator and show sequential binding to a set of overlapping binding sites. the assembly of these initiator complexes is controlled by a gradual reduction in the dependence of int ...200212370317
atomic model of the papillomavirus capsid.papillomaviruses propagate in differentiating skin cells, and certain types are responsible for the onset of cervical cancer. we have combined image reconstructions from electron cryomicroscopy (cryoem) of bovine papillomavirus at 9 a resolution with coordinates from the crystal structure of small virus-like particles of the human papillomavirus type 16 l1 protein to generate an atomic model of the virion. the overall fit of the l1 model into the cryoem map is excellent, but residues 402-446 in ...200212234916
transcriptional activity among high and low risk human papillomavirus e2 proteins correlates with e2 dna binding.the full-length e2 protein, encoded by human papillomaviruses (hpvs), is a sequence-specific transcription factor found in all hpvs, including cancer-causing high risk hpv types 16 and 18 and wart-inducing low risk hpv types 6 and 11. to investigate whether e2 proteins encoded by high risk hpvs may function differentially from e2 proteins encoded by low risk hpvs and animal papillomaviruses, we conducted comparative dna-binding and transcription studies using electrophoretic mobility shift assay ...200212239214
life cycle heterogeneity in animal models of human papillomavirus-associated disease.animal papillomaviruses are widely used as models to study papillomavirus infection in humans despite differences in genome organization and tissue tropism. here, we have investigated the extent to which animal models of papillomavirus infection resemble human disease by comparing the life cycles of 10 different papillomavirus types. three phases in the life cycles of all viruses were apparent using antibodies that distinguish between early events, the onset of viral genome amplification, and th ...200212239317
viral disease transmitted by laser-generated plume (aerosol).to evaluate the possibility of disease transmission through liberated plume from virally infected tissue that is exposed to the carbon dioxide laser.200212374535
regulation of bovine papillomavirus replicative helicase e1 by the ubiquitin-proteasome pathway.papillomaviruses maintain their genomes in a relatively constant copy number as stable extrachromosomal plasmids in the nuclei of dividing host cells. the viral initiator of replication, e1, is not detected in papillomavirus-infected cells. here, we present evidence that e1 encoded by bovine papillomavirus type 1 is an unstable protein that is degraded through the ubiquitin-proteasome pathway. in a cell-free system derived from xenopus egg extracts, e1 degradation is regulated by both cyclin e/c ...200212388695
peptides containing cyclin/cdk-nuclear localization signal motifs derived from viral initiator proteins bind to dna when unphosphorylated.a single phosphorylation event at t-antigen residue thr124 regulates initiation of simian virus 40 dna replication. to explore this regulatory process, a series of peptides were synthesized, centered on thr124. these peptides contain a nuclear localization signal (nls) and a recognition site for cyclin/cdk kinases. when unphosphorylated, the "cdk/nls" peptides inhibit t-antigen assembly and bind non-sequence specifically to dna. however, these activities are greatly reduced upon phosphorylation ...200212414920
saccharomyces cerevisiae is permissive for replication of bovine papillomavirus type 1.we recently demonstrated that saccharomyces cerevisiae protoplasts can take up bovine papillomavirus type 1 (bpv1) virions and that viral episomal dna is replicated after uptake. here we demonstrate that bpv virus-like particles are assembled in infected s. cerevisiae cultures from newly synthesized capsid proteins and also package newly synthesized dna, including full-length and truncated viral dna and s. cerevisiae-derived dna. virus particles prepared in s. cerevisiae are able to convey packa ...200212414966
the bovine papillomavirus oncoprotein e5 retains mhc class i molecules in the golgi apparatus and prevents their transport to the cell surface.during papillomavirus infection, the e5 protein localizes in the cell golgi apparatus and other endomembrane compartments. cells transformed by e5 do not express major histocompatibility class i complex (mhc i) on the cell surface, while cells transformed by the other transforming proteins e6 and e7 do. in addition, the total amount of both mhc i protein and mrna is reduced in e5-transformed cells. here we show that expression of bovine papillomavirus e5 causes the retention of mhc i in the golg ...200212420217
dna from bovine papillomavirus type 2 induces warts in a xenograft model.bovine papillomavirus (bpv) type 2 dna was inoculated into calf scrotal skin before grafting onto severe combined immunodeficient mice. inoculation with viral dna isolated from a bovine wart induced fibropapillomas that exhibited all the morphological features of a bpv infection in cattle. the production of capsid protein and infectious bpv2 particles was demonstrated by immunohistochemistry and a transformed cell focus assay. in contrast, the injection of molecularly cloned viral genomic dna le ...200212457989
exonic splicing enhancer-dependent selection of the bovine papillomavirus type 1 nucleotide 3225 3' splice site can be rescued in a cell lacking splicing factor asf/sf2 through activation of the phosphatidylinositol 3-kinase/akt pathway.bovine papillomavirus type 1 (bpv-1) late pre-mrnas are spliced in keratinocytes in a differentiation-specific manner: the late leader 5' splice site alternatively splices to a proximal 3' splice site (at nucleotide 3225) to express l2 or to a distal 3' splice site (at nucleotide 3605) to express l1. two exonic splicing enhancers, each containing two asf/sf2 (alternative splicing factor/splicing factor 2) binding sites, are located between the two 3' splice sites and have been identified as regu ...200312525645
bovine papillomavirus type 4 in oesophageal papillomas of cattle from the south of italy.oesophageal papillomas are known to occur in cattle infected with bovine papillomavirus type 4 (bpv-4), and bpv-4 papillomas may undergo malignant progression in cattle that feed on bracken fern. in the south of italy, where bracken fern is common, examination of 1133 slaughterhouse cattle aged 4-12 years revealed oesophageal lesions (single or multiple peduncuolated proliferations, or mucosal thickening) in 147 (13%). these two types of lesion were consistent with exophytic and inverted papillo ...200312634101
expression of the bovine papillomavirus type 1 e5b gene reveals a protein-protein interaction of the e5a and e5b gene products.the bovine papillomavirus type 1 (bpv-1) genome has been shown to contain a small open-reading frame designated e5b (nucleotides 4013-4167) which is predicted to encode a hydrophobic, 52 amino acid protein. in order to detect and characterize the e5b protein, an 18 nucleotide sequence encoding a 6 amino acid epitope was added to the 3' end of the e5b open-reading frame which was then expressed in cos-1 cells using a sv40 vector. immunoprecipitation, immunofluorescence, and cell fractionation stu ...200312667807
papillomaviruses infect cells via a clathrin-dependent this study we have examined the pathway by which papillomaviruses infect cells, using bovine papillomavirus (bpv) virions and mouse c127 cells as the model system. by confocal microscopy, the entry of bpv virions, bpv virus-like particles (vlps), and hpv16 vlps were very similar. in dually exposed cells, hpv-16 vlps and bpv virions colocalized intracellularly. bpv vlps colocalized with ap-2, a clathrin adapter molecular and a marker of the clathrin-dependent endocytic pathway; and also with t ...200312667809
interaction of l2 with beta-actin directs intracellular transport of papillomavirus and infection.viruses that replicate in the nucleus, including the primary causative agent of cervical cancer, human papillomavirus type 16 (hpv16), must first cross the cytoplasm. we compared the uptake of hpv16 virus-like particles (vlps) either with or without the minor capsid protein l2. whereas vlps containing only the major capsid protein l1 were diffusely distributed within the cytoplasm even 6 h post-infection, vlps comprising both l1 and l2 exhibited a radial distribution in the cytoplasm and accumul ...200312560332
e1 initiator dna binding specificity is unmasked by selective inhibition of non-specific dna binding.initiator proteins are critical components of the dna replication machinery and mark the site of initiation. this activity probably requires highly selective dna binding; however, many initiators display modest specificity in vitro. we demonstrate that low specificity of the papillomavirus e1 initiator results from the presence of a non-specific dna-binding activity, involved in melting, which masks the specificity intrinsic to the e1 dna-binding domain. the viral factor e2 restores specificity ...200312574131
cell surface-binding motifs of l2 that facilitate papillomavirus infection.human papillomavirus type 16 (hpv16) is the primary etiologic agent of cervical carcinoma, whereas bovine papillomavirus type 1 (bpv1) causes benign fibropapillomas. however, the capsid proteins, l1 and l2, of these divergent papillomaviruses exhibit functional conservation. a peptide comprising residues 1 to 88 of bpv1 l2 binds to a variety of cell lines, but not to the monocyte-derived cell line d32, and blocks bpv1 infection of mouse c127 cells. residues 13 to 31 of hpv16 l2 and bpv1 l2 resid ...200312610128
the papillomavirus e2 protein binds to and synergizes with c/ebp factors involved in keratinocyte differentiation.the papillomavirus life cycle is closely linked to the differentiation program of the host keratinocyte. thus, late gene expression and viral maturation are restricted to terminally differentiated keratinocytes. a variety of cellular transcription factors including those of the c/ebp family are involved in the regulation of keratinocyte differentiation. in this study we show that the papillomavirus transcription factor e2 cooperates with c/ebpalpha and -beta in transcriptional activation. this s ...200312692227
association of bovine papillomavirus with the equine sarcoid.the equine sarcoid, a locally aggressive, fibroblastic skin tumour, is the most common dermatological neoplasm reported in horses; there is no consistently effective therapy. it is widely accepted that bovine papillomavirus (bpv) types 1 and 2 are associated with the pathogenesis of sarcoid disease. most sarcoids appear to contain detectable viral dna and rna and are also known to express the bpv types 1 and 2 major transforming protein, e5, but appear not to produce infectious virions. while th ...200312692268
effective generation of transgenic mice by bovine papillomavirus type 1 based self-replicating plasmid that is maintained as extrachromosomal genetic element in three generations of animals.the objective of our study was to analyze the efficiency and the properties of the inheritance of the bovine papillomavirus type 1 (bpv1) replicator-based plasmid used as vector system for generation of transgenic animals. previously, we have characterized a series of self-replicating plasmid vectors containing all viral factors necessary and sufficient for stable extrachromosomal replication of the bpv1 genome in the tissue culture system. we also demonstrated that the designed replicating vect ...200312749834
extensive papillomatosis of the bovine upper gastrointestinal tract.extensive papillomatosis was identified in a heifer born and raised in scotland and a steer born and raised in england. in both cases, the papillomas extended from the mouth and tongue to the reticulum. although cases of florid papillomatosis of the upper gastrointestinal tract occur relatively frequently in cattle grazing on bracken fern in the scottish highlands, no such cases have been reported previously in english cattle. histopathological examination of the papillomas showed that the lesio ...200312921714
transcriptome signature of irreversible senescence in human papillomavirus-positive cervical cancer cells.a frequent characteristic of human papillomavirus (hpv)-positive cervical cancers is the loss of viral e2 gene expression in hpv-infected cervical epithelial cells as a consequence of viral dna integration into the cellular genome. the expression of e2 in hpv-positive cancer cells results in the repression of the viral e6/e7 oncogenes, activation of the p53 and prb pathways, and a g1 cell cycle arrest, followed by induction of cellular senescence. the transcriptional consequences of e2-mediated ...200312756294
construction and production of fluorescent papillomavirus-like particles.the green fluorescent protein (gfp) from the jellyfish aequorea victoria has attracted widespread interest since it was demonstrated to be fluorescent in vivo when expressed in other organisms. in order to investigate papillomavirus life cycle which hampered by the unavailability of conventional cell culture system, we constructed a chimeric bovine papillomavirus (bpv) type 1 virus-like particles (vlps) containing gfp. it was found that fluorescent vlps could be assembled from l2 protein in whic ...199912840887
tyrphostin ag 555 inhibits bovine papillomavirus transcription by changing the ratio between e2 transactivator/repressor function.the tyrosine kinase inhibitor (tyrphostin) ag 555 selectively interferes with viral transcription in bovine papillomavirus type 1 (bpv-1)-transformed fibroblasts and induces suppression of cyclin-dependent kinase activity and cell cycle arrest. concomitant with inhibition of viral transcription, c-jun was strongly up-regulated, which was consistent with the observation that ag 555 treatment also led to an activation of the mitogen-activated protein kinase pathway by enhancing phosphorylation of ...200312867421
angiokeratomatous papilloma associated with papillomavirus in a calf.a female 8-month-old simmental calf was presented with a history of a gradually enlarging mass in the ventral abdominal skin since 4 months of age. the mass was well circumscribed, lightly pigmented, and rough surfaced with many fine fissures and was attached to the skin by a relatively broad pedicle. on cut section, there was a border between the reddish-black stroma and overlying epithelium, including hemorrhagic foci of variable sizes. histologically, the tumor was papillomatous with angioker ...200312949419
presence of bovine papillomavirus type 2 dna and expression of the viral oncoprotein e5 in naturally occurring urinary bladder tumours in cows.samples of neoplastic and normal urothelium were obtained from cows originating from areas of southern italy, a region in which chronic enzootic haematuria is endemic and bracken fern infestation is widespread. specimens were analysed for bovine papillomavirus type 2 (bpv-2) dna, bpv-2 e5 expression and telomerase activity. a total of 46 of 60 tumours and 17 of 34 normal bladder mucosa samples harboured bpv-2 dna. analysis of a subset of samples showed e5 protein expression and telomerase activi ...200314573796
two separate replication modes of the bovine papillomavirus bpv1 origin of replication that have different sensitivity to p53.we have shown previously that transient amplificational replication of reporter plasmids that carry the papillomavirus origin of replication is efficiently blocked by p53 protein in several cell lines. we demonstrate now that the replication of stably maintained episomal bovine papillomavirus bpv1 urr (upstream regulatory region) reporter plasmid is not sensitive to p53. in addition, these two replication modes--initial transient amplificational replication and stable maintenance replication of ...200312951267
sequence variants of bovine papillomavirus e5 detected in equine sarcoids.the equine sarcoid, one of the most common dermatological lesions in equids, is a benign, locally invasive dermal fibroblastic lesion. previous studies have suggested an association with two bovine papilloma virus (bpv) types, bpv-1 and bpv-2. in the present study, we examined sarcoids from horses from two geographical areas, switzerland and the uk, for the major transforming gene of bpv, e5. we detected bpv dna for the e5 open reading frame and viral e5 rna transcripts in most sarcoids. sequenc ...200312951274
il-10 mediates suppression of the cd8 t cell ifn-gamma response to a novel viral epitope in a primed host.priming to ag can inhibit subsequent induction of an immune response to a new epitope incorporated into that ag, a phenomenon referred to as original antigenic sin. in this study, we show that prior immunity to a virus capsid can inhibit subsequent induction of the ifn-gamma effector t cell response to a novel cd8-restricted antigenic epitope associated with the virus capsid. inhibition does not involve ab to the virus capsid, as it is observed in animals lacking b cells. cd8-restricted virus-sp ...200314568953
production of functional recombinant tyrosine hydroxylase by the bpv-1 expression plasmids in the cell cultures.bovine papilloma virus type-1 (bpv-1)-based expression plasmids tkbpvth and cgalbpvth encoding the rat tyrosine hydroxylase (th) enzyme have been designed for the development of gene therapy for experimental parkinson's disease. the aim of the present work was to examine the transfection of bpvth plasmids to express a dopaminergic transgene in the monkey cv1-p fibroblast, rat c6 glioma and human nha astrocyte cell cultures. the biological function of the transgene was estimated by analyzing the ...200314597011
dna fine structure and dynamics in crystals and in solution: the impact of bi/bii backbone conformations.sugar-phosphate backbone conformations are an important structural element for a complete understanding of specific recognition in nucleic acid-protein interactions. they can be involved both in early stages of target discrimination and in structural adaptation upon binding. in the first part of this study, we have analyzed high-resolution structures of double-stranded b-dna either isolated or bound to proteins, and explored the impact of both the standard bi and the unusual bii phosphate backbo ...200414755572
molecular dynamics simulations of papilloma virus e2 dna sequences: dynamical models for oligonucleotide structures in solution.the specificity of papilloma virus e2 protein-dna binding depends critically upon the sequence of a region of the dna not in direct contact with the protein, and represents one of the simplest known examples of indirect readout. a detailed characterization of this system in solution is important to the further investigation hypothesis of a structural code for dna recognition by regulatory proteins. in the crystalline state, the e2 dna oligonucleotide sequence, d(accgaattcggt), exhibits three dif ...200414755573
efficient intracellular assembly of papillomaviral vectors.although the papillomavirus structural proteins, l1 and l2, can spontaneously coassemble to form virus-like particles, currently available methods for production of l1/l2 particles capable of transducing reporter plasmids into mammalian cells are technically demanding and relatively low-yield. in this report, we describe a simple 293 cell transfection method for efficient intracellular production of papillomaviral-based gene transfer vectors carrying reporter plasmids. using bovine papillomaviru ...200414694107
transition to an irreversible state of senescence in hela cells arrested by repression of hpv e6 and e7 genes.inhibition of human papillomavirus (hpv) e6 and e7 transcription by means of the e2 protein of bovine papillomavirus 1 (bpv1) has been shown to induce acute growth arrest in hpv-positive cervical carcinoma cells. this state of arrest is marked by the expression of senescence phenotypes including sa beta-gal activity and lipofuscin accumulation. in this study, we examined the reversibility of these phenotypes by exogenously expressing the e6 and e7 genes into hela cells growth-arrested by the dep ...200414706235
analysis of chromatin attachment and partitioning functions of bovine papillomavirus type 1 e2 protein.recent studies have suggested that the tethering of viral genomes to host cell chromosomes could provide one of the ways to achieve their nuclear retention and partitioning during extrachromosomal maintenance in dividing cells. the data we present here provide firm evidence that the partitioning of the bovine papillomavirus type 1 (bpv1) genome is dependent on the chromatin attachment process mediated by viral e2 protein and its multiple binding sites. on the other hand, the attachment of e2 and ...200414747575
bovine papillomavirus replicative helicase e1 is a target of the ubiquitin ligase apc.the papillomavirus e1 replicative helicase is essential for replication and maintenance of extrachromosomal viral genomes in infected cells. we previously found that the bovine papillomavirus e1 protein is a substrate of the ubiquitin-dependent proteolytic pathway. here we show that e1 is targeted for degradation by the anaphase-promoting complex (apc). inhibition of apc activity by the specific inhibitor emi1 or point mutations in the d-box and ken-box motifs of e1 stabilize the protein and inc ...200414963168
reactivity of human sera in a sensitive, high-throughput pseudovirus-based papillomavirus neutralization assay for hpv16 and hpv18.sensitive high-throughput neutralization assays, based upon pseudoviruses carrying a secreted alkaline phosphatase (seap) reporter gene, were developed and validated for human papillomavirus (hpv)16, hpv18, and bovine papillomavirus 1 (bpv1). seap pseudoviruses were produced by transient transfection of codon-modified papillomavirus structural genes into an sv40 t antigen expressing line derived from 293 cells, yielding sufficient pseudovirus from one flask for thousands of titrations. in a 96-w ...200415051381
clinical and immunological effects of newcastle disease virus vaccine on bovine papillomatosis.newcastle disease virus (ndv) has antineoplastic and immunostimulatory properties, and it is currently being clinically tested in anticancer therapy. in order to analyze the immunostimulatory effects of ndv on bovine papillomatosis, we inoculated 14 cows subcutaneously with an attenuated vaccine containing the lasota strain of ndv (ls-ndv). four cows with papillomatosis served as controls. serum samples were collected from each animal 1 h before and, 7 and 21 days after inoculation. in inoculate ...200415127837
overcoming antigen masking of anti-amyloidbeta antibodies reveals breaking of b cell tolerance by virus-like particles in amyloidbeta immunized amyloid precursor protein transgenic prior work we detected reduced anti-abeta antibody titers in abeta-vaccinated transgenic mice expressing the human amyloid precursor protein (app) compared to nontransgenic littermates. we investigated this observation further by vaccinating app and nontransgenic mice with either the wild-type human abeta peptide, an abeta peptide containing the "dutch mutation", e22q, or a wild-type abeta peptide conjugated to papillomavirus virus-like particles (vlps).200415186505
hitchhiking without covalent eukaryotes, many latent viruses attach to mitotic chromosomes noncovalently for effective partitioning in dividing cells. for different viruses, the cis and trans elements encoded by the episomes have been effectively defined but the chromosomal "receptors" for such tethering have remained elusive. in this issue of cell, give us a first insight into the cellular protein machinery important for animal papillomavirus retention.200415109488
interaction of the bovine papillomavirus e2 protein with brd4 tethers the viral dna to host mitotic chromosomes.the papillomavirus e2 protein tethers viral genomes to host mitotic chromosomes to ensure genome maintenance. we have identified the bromodomain protein brd4 as a major cellular interacting partner of the bovine papillomavirus e2. brd4 associates with mitotic chromosomes and colocalizes with e2 on mitotic chromosomes. the site of e2 binding maps to the c-terminal domain of brd4. expression of this c-terminal brd4 domain functions in a dominant-negative manner to abrogate the colocalization of e2 ...200415109495
induction of mucosal and systemic neutralizing antibodies against human immunodeficiency virus type 1 (hiv-1) by oral immunization with bovine papillomavirus-hiv-1 gp41 chimeric virus-like particles.human immunodeficiency virus type 1 (hiv-1) envelope-specific neutralizing antibodies are generated late after initial infection, and the neutralizing antibody response is weak in the infected individuals. administration of neutralizing antibodies such as 2f5 to hiv-1-infected individuals resulted in reductions in viral loads. because hiv-1 is transmitted mainly via mucosa and because hiv-specific neutralizing antibodies reduce hiv-1 in infected individuals, a vaccine that can induce both mucosa ...200415254206
trnaser(cga) differentially regulates expression of wild-type and codon-modified papillomavirus l1 genes.exogenous transfer rnas (trnas) favor translation of bovine papillomavirus 1 wild-type (wt) l1 mrna in in vitro translation systems (zhou et al. 1999, j. virol., 73, 4972-4982). we, therefore, investigated whether papillomavirus (pv) wt l1 protein expression could be enhanced in eukaryotic cells following exogenous trna supplementation. both chinese hamster ovary (cho) and cos1 cells, transfected with pv1 wt l1 genes, effectively transcribed the genes but did not translate them. however, l1 prot ...200415319446
broad-spectrum detection of papillomaviruses in bovine teat papillomas and healthy teat investigate the prevalence of bovine papillomavirus (bpv) in bovine papilloma and healthy skin, dna extracted from teat papillomas and healthy teat skin swabs was analysed by pcr using the primer pairs fap59/fap64 and my09/my11. papillomavirus (pv) dna was detected in all 15 papilloma specimens using fap59/fap64 and in 8 of the 15 papilloma specimens using my09/my11. in swab samples, 21 and 8 of the 122 samples were pv dna positive using fap59/fap64 and my09/my11, respectively. four bpv types ...200415269358
chromosome aberrations in cattle with chronic enzootic haematuria.chromosomal aberrations were investigated in 56 cattle with chronic enzootic haematuria (ceh) raised on pastures giving access to bracken fern. of these animals, 27 were slaughtered and showed neoplastic lesions of the urinary bladder. tumour tissue from 11 of the 27 cattle contained bovine papillomavirus type 2 (bpv-2) dna. increased numbers of chromosomal aberrations were seen in all animals with ceh, as compared with 30 control cattle that had had no access to bracken fern. the highest clasto ...200415276863
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