| 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 ... | 2000 | 11070078 |
| human papillomavirus type 16 e5 protein localizes to the golgi apparatus but does not grossly affect cellular glycosylation. | the e5 protein of papillomaviruses is a strongly hydrophobic membrane protein that can associate with the 16 kda protein subunit of the vacuolar proton atpase in endosomes and the golgi apparatus resulting in raise of intraorganelle ph. we demonstrate that e5 of human papillomavirus type 16 (hpv16) when transfected into human keratinocytes localizes to the golgi. using facs analysis and western blotting with a variety of lectins as well as analysing the sialylation status of a specific cell surf ... | 2000 | 11087100 |
| 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 ... | 2000 | 11087426 |
| 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 ... | 2001 | 11119599 |
| cooperative transformation and coexpression of bovine papillomavirus type 1 e5 and e7 proteins. | productively infected bovine fibropapillomas were examined for bovine papillomavirus type 1 (bpv-1) e7 localization. bpv-1 e7 was observed in the cytoplasm of basal and lower spinous epithelial cells, coexpressed in the cytoplasm of basal cells with the e5 oncoprotein. e7 was also observed in nucleoli throughout the basal and spinous layers but not in the granular cell layer. ectopic expression of e7 in cultured epithelial cells gave rise to localization similar to that seen in productive fibrop ... | 2001 | 11119620 |
| orientation of a novel dna binding site affects human papillomavirus-mediated transcription and replication. | a consensus binding site for the human papillomavirus (hpv) e2 protein was determined from an unbiased set of degenerate oligonucleotides using cyclic amplification and selection of targets (casting). detectable dna-protein complexes were formed after six to nine cycles of casting. a population of selected binding sites was cloned, and a consensus was determined by statistical analysis of the dna sequences of individual isolates. starting from a pool with 20 random bases, a consensus binding sit ... | 2001 | 11160670 |
| 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 ... | 2001 | 11161855 |
| 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 ... | 2001 | 11170455 |
| 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 ... | 2001 | 11199158 |
| 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 ... | 2001 | 11222708 |
| 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 ... | 2001 | 11257010 |
| generation of sequence-specific, high affinity anti-dna antibodies. | by taking advantage of the extreme stability of a protein-dna complex, we have obtained two highly specific monoclonal antibodies against a predetermined palindromic dna sequence corresponding to the binding site of the e2 transcriptional regulator of the human papillomavirus (hpv-16). the purified univalent antibody fragments bind to a double-stranded dna oligonucleotide corresponding to the e2 binding site in solution with dissociation constants in the low and subnanomolar range. this affinity ... | 2001 | 11279040 |
| 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 ... | 2001 | 11287582 |
| 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 ... | 2001 | 11289806 |
| 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 ... | 2001 | 11311423 |
| bovine papillomavirus oncoprotein e5 affects the arachidonic acid metabolism in cells. | the bovine papillomavirus type 1 (bpv-1) oncoprotein encoded by the e5 orf is a small highly hydrophobic protein, which is capable of inducing oncogenic transformation of cells. we studied the effect of the bpv-1 e5 protein expression on the arachidonic acid metabolism in monkey (cos1) and human (c33a) cells. at relatively low protein concentrations the phospholipase a(2) (pla(2)) activity and the arachidonic acid (aa) metabolism are activated. e5 mutant proteins, lacking cysteines responsible f ... | 2001 | 11311854 |
| regression of canine oral papillomas is associated with infiltration of cd4+ and cd8+ lymphocytes. | canine oral papillomavirus (copv) infection is used in vaccine development against mucosal papillomaviruses. the predictable, spontaneous regression of the papillomas makes this an attractive system for analysis of cellular immunity. immunohistochemical analysis of the timing and phenotype of immune cell infiltration revealed a marked influx of leukocytes during wart regression, including abundant cd4+ and cd8+ cells, with cd4+ cells being most numerous. comparison of these findings, and those o ... | 2001 | 11312659 |
| 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 ... | 2001 | 11313370 |
| 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 ... | 2001 | 11317341 |
| 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 ... | 2001 | 11323428 |
| 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 ... | 2001 | 11325464 |
| bovine papillomavirus dna in neoplastic and nonneoplastic tissues obtained from horses with and without sarcoids in the western united states. | to 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. | 2001 | 11341396 |
| 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 ... | 2001 | 11352485 |
| evaluation of formalin-fixed paraffin-embedded tissues from vaccine site-associated sarcomas of cats for papillomavirus dna and antigen. | to determine whether vaccine site-associated sarcomas (vss) from cats contain papillomavirus antigen or dna. | 2001 | 11400837 |
| 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 ... | 2001 | 11408351 |
| identification of the transmembrane dimer interface of the bovine papillomavirus e5 protein. | we have developed a genetic method to determine the active orientation of dimeric transmembrane protein helices. the bovine papillomavirus e5 protein, a 44-amino acid homodimeric protein that appears to traverse membranes as a left-handed coiled-coil, transforms fibroblasts by binding and activating the platelet-derived growth factor (pdgf) beta receptor. a heterologous dimerization domain was used to force e5 monomers to adopt all seven possible symmetric coiled-coil registries relative to one ... | 2001 | 11439346 |
| 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 ... | 2001 | 11448948 |
| expression of a transforming gene (e5) of bovine papillomavirus in sarcoids obtained from horses. | to 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. | 2001 | 11497440 |
| efficiency of delivery of dna to cells by bovine papillomavirus type-1 l1/l2 pseudovirions. | to 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 ... | 2001 | 11499923 |
| polymerase chain reaction analysis of the surgical margins of equine sarcoids for bovine papilloma virus dna. | to 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. | 2001 | 11555822 |
| effects of mutations within two hydrophilic regions of the bovine papillomavirus type 1 e1 dna-binding domain on e1-e2 interaction. | the interaction between papillomavirus e1 and e2 proteins is essential for viral genome replication. using both in vivo and in vitro assays to evaluate the regions of the two proteins necessary for the e1-e2 interaction, three independent interactions were identified for bovine papillomavirus e1: the n terminus of e1 (e1n, residues 1-311) interacts with the e2 transactivation domain (e2tad) and the e2 dna-binding domain (e2dbd) and the c terminus of e1 (e1c, residues 315-605) interacts with e2. ... | 2001 | 11562528 |
| e5 transforming proteins of papillomaviruses do not disturb the activity of the vacuolar h(+)-atpase. | papillomaviruses contain a gene, e5, that encodes a short hydrophobic polypeptide that has transforming activity. e5 proteins bind to the 16 kda subunit c (proteolipid) of the eukaryotic vacuolar h(+)-atpase (v-atpase) and this binding is thought to disturb the v-atpase and to be part of transformation. this link has been examined in the yeast saccharomyces cerevisiae. the e5 proteins from human papillomavirus (hpv) type 16, bovine papillomavirus (bpv) type 1, bpv-4 e5 and various mutants of e5 ... | 2001 | 11562529 |
| 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. | 2001 | 11581419 |
| 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 ... | 2001 | 11602792 |
| 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 ... | 2001 | 11709319 |
| 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 ... | 2001 | 11711585 |
| induced senescence in hela cervical carcinoma cells containing elevated telomerase activity and extended telomeres. | proliferation of normal somatic human cells in culture is limited by replicative senescence, a growth-arrested state that appears to be triggered by the erosion of telomeres. tumor cells such as hela cervical carcinoma cells, which contain short telomeres, can be induced to undergo senescence by various manipulations including oncogene withdrawal. repression of the human papillomavirus (hpv) type 18 e6/e7 genes in hela cells by the bovine papillomavirus e2 transcriptional regulatory protein resu ... | 2001 | 11714633 |
| 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 ... | 2001 | 11735366 |
| 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 ... | 2001 | 11753669 |
| 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 ... | 2002 | 11803468 |
| 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 ... | 2002 | 11853393 |
| 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 ... | 2002 | 11864754 |
| functional analysis of a carboxyl-terminal phosphorylation mutant of the bovine papillomavirus e1 protein. | the papillomavirus e1 protein is essential for viral dna replication, and phosphorylation of e1 appears to regulate protein function and dna replication. serine 584 of bovine papillomavirus e1 is in a conserved motif resembling a ck2 consensus site, and is phosphorylated by ck2 in vitro. mutation of serine 584 to alanine eliminates replication of the viral genome in transient replication assays. wild-type and mutant e1 proteins were expressed from recombinant baculoviruses and used to assess bio ... | 2002 | 11866520 |
| route of administration of chimeric bpv1 vlp determines the character of the induced immune responses. | to examine the mucosal immune response to papillomavirus virus-like particles (pv-vlp), mice were immunized with vlp intrarectally (i.r.), intravaginally (i.va.) 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 i.va. immu ... | 2002 | 11869359 |
| stable replication of papillomavirus genomes in saccharomyces cerevisiae. | papillomaviruses normally replicate in stratified squamous epithelial tissues of their mammalian hosts, in which the viral genome is found as a nuclear plasmid. two viral proteins, e1, a helicase, and e2, a transcriptional activator and plasmid maintenance factor, are known to contribute to the episomal replication of the viral genome. recently, our laboratory discovered that papillomaviruses can also replicate in an e1-independent manner in mammalian cells (k. kim and p. f. lambert, virology, i ... | 2002 | 11884560 |
| 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 ... | 2002 | 11884561 |
| 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 ... | 2002 | 11884568 |
| 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 ... | 2002 | 11889054 |
| 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 ... | 1983 | 11892800 |
| c-src activation by the e5 oncoprotein enables transformation independently of pdgf receptor activation. | the e5 oncoprotein of bovine papillomavirus type 1 is a golgi-resident, hydrophobic polypeptide that can transform immortalized fibroblasts by activating endogenous platelet-derived growth factor receptor beta (pdgf-r). however, the existence of e5 mutants that dissociate transformation from pdgf-r activation implies that there are additional mechanism(s) by which e5 can transform cells. we now show that both wt e5, and transforming e5 mutants that are defective for pdgf-r activation, constituti ... | 2002 | 11896601 |
| 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. | 2002 | 11967145 |
| 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 ... | 2002 | 11992014 |
| 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 ... | 2002 | 12033781 |
| 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 ... | 2002 | 12036317 |
| intracutaneous dna vaccination with the e8 gene of cottontail rabbit papillomavirus induces protective immunity against virus challenge in rabbits. | the cottontail rabbit papillomavirus (crpv)-rabbit model has been used in several studies for testing prophylactic and therapeutic papillomavirus vaccines. earlier observations had shown that the crpv nonstructural genes e1, e2, and e6 induced strong to partial protective immunity against crpv infection. in this study, we found that crpv e8 immunization eliminated virus-induced papillomas in eiii/jc inbred rabbits (100%) and provided partial protection (55%) against virus challenge in outbred ne ... | 2002 | 12050357 |
| a bovine papillomavirus-1 based vector restores the function of the low-density lipoprotein receptor in the receptor-deficient cho-ldla7 cell line: correction. | | 2002 | 12060487 |
| induction of senescence-like state and suppression of telomerase activity through inhibition of hpv e6/e7 gene expression in cells immortalized by hpv16 dna. | the e6 and e7 oncoproteins of human papillomavirus (hpv) play a major role in the development of cervical carcinoma. in this study, a recombinant adenovirus that expresses the bovine papillomavirus (bpv) e2, which has been shown to inhibit hpv early gene expression, was delivered to two hpv-immortalized cell lines as well as caski, a cervical carcinoma cell line. we tested whether the carcinoma and the immortal cells were equally affected by the expression of bpv e2. in all cell lines, bpv e2-me ... | 2002 | 12083799 |
| 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 ... | 2002 | 12086149 |
| priming of human papillomavirus type 11-specific humoral and cellular immune responses in college-aged women with a virus-like particle vaccine. | in this study, we evaluated the potency of a human papillomavirus (hpv) virus-like particle (vlp)-based vaccine at generating hpv type 11 (hpv-11)-specific cellular and humoral immune responses in seronegative women. the vaccine was administered by intramuscular immunizations at months 0, 2, and 6. a fourth immunization was administered to approximately half of the women at month 12. all vaccine recipients had positive hpv-11 vlp-specific lymphoproliferative responses at month 3 following the se ... | 2002 | 12097595 |
| 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 ... | 2002 | 12112459 |
| [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. | 2002 | 12133476 |
| 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 ... | 2002 | 12134002 |
| interaction of oncogenic papillomavirus e6 proteins with fibulin-1. | human papillomavirus (hpv) infection is the primary risk factor for the development of cervical cancer. the papillomavirus e6 gene is essential for virus-induced cellular transformation and the viral life cycle. important insight into the mechanism of e6 function came from the discovery that cancer-related hpv e6 proteins promote the degradation of the tumor suppressor p53. however, mounting evidence indicates that interaction with p53 does not mediate all e6 activities. to explore the p53-indep ... | 2002 | 12200142 |
| frequency of p12k and p12r alleles of htlv type 1 in ham/tsp patients and in asymptomatic htlv type 1 carriers. | htlv-1 has a complex genome, and contains four open reading frames (orfs) in the 3' region encoding viral and cellular regulatory proteins. p12 is a small, orf i-encoded hydrophobic protein, the function of which is not well understood. it has been shown that p12 enhances the e5-transforming ability of bovine papillomavirus; and binds to the 16-kda subunit of the vacuolar atpase pump, immature forms of the beta and gamma(c) chains of the interleukin 2 receptor, and the free chain of mhc i. p12 c ... | 2002 | 12230932 |
| 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 ... | 2002 | 12234916 |
| 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 ... | 2002 | 12239214 |
| 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 ... | 2002 | 12239317 |
| molecular examination of the transmembrane requirements of the platelet-derived growth factor beta receptor for a productive interaction with the bovine papillomavirus e5 oncoprotein. | the small transmembrane e5 protein of bovine papillomavirus (bpv) transforms cells by forming a stable complex with and activating the platelet-derived growth factor beta receptor (pdgfbetar). the e5/pdgfbetar interaction is thought to involve specific physical contacts between the transmembrane domains of the two proteins. lys(499) at the extracellular juxtamembrane position and thr(513) within the transmembrane domain of the pdgfbetar are required for the interaction and are predicted to conta ... | 2002 | 12351659 |
| 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 ... | 2002 | 12370317 |
| 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. | 2002 | 12374535 |
| 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 ... | 2002 | 12388695 |
| 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 ... | 2002 | 12414920 |
| 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 ... | 2002 | 12414966 |
| 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 ... | 2002 | 12420217 |
| chimaeric hpv e6 proteins allow dissection of the proteolytic pathways regulating different e6 cellular target proteins. | the ability of hpv e6 oncoproteins to induce the degradation of pdz domain-containing maguk proteins correlates with their malignant potential. we previously showed that the hpv-6 e6 protein, when provided with the pdz-binding domain from hpv-18 e6, acquires the ability to bind the discs large (dlg) tumour suppressor and target it for degradation. based on this finding we have extended this analysis to e6 proteins from a variety of different papillomavirus types. cloning a pdz-binding sequence o ... | 2002 | 12444549 |
| 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 ... | 2002 | 12457989 |
| apoptosis of mortal human fibroblasts transformed by the bovine papillomavirus e5 oncoprotein. | mortal human fibroblasts can be partially transformed by the bovine papillomavirus e5 oncoprotein through activation of the platelet-derived growth factor beta receptor. here, we report that these cells undergo massive apoptosis 2 weeks after confluence. although activation of caspase 3 was observed in the apoptotic cells, it was not required for apoptosis. the appearance of the mitochondrial proteins cytochrome c and apoptosis-inducing factor in cytosolic and nuclear compartments, respectively, ... | 2002 | 12496359 |
| endogenous human papillomavirus e6 and e7 proteins differentially regulate proliferation, senescence, and apoptosis in hela cervical carcinoma cells. | cervical cancer cells express high-risk human papillomavirus (hpv) e6 and e7 proteins, and repression of hpv gene expression causes the cells to cease proliferation and undergo senescence. however, it is not known whether both hpv proteins are required to maintain the proliferative state of cervical cancer cells, or whether mutations that accumulate during carcinogenesis eliminate the need for one or the other of them. to address these questions, we used the bovine papillomavirus e2 protein to r ... | 2003 | 12502868 |
| 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 ... | 2003 | 12525645 |
| positively charged sequences of human papillomavirus type 16 capsid proteins are sufficient to mediate gene transfer into target cells via the heparan sulfate receptor. | using synthetic peptides we have shown that positively charged sequences present at the c terminus of the l1 protein and the n and c termini of the l2 protein of human papillomavirus type 16 (hpv-16) bind to both dna and heparan sulfate receptors. moreover, these short amino acid sequences are sufficient to mediate gene transfer in cos-7 cells. the l1 proteins of other hpvs were shown to contain one or two dna- and heparin-binding sequences that have the capacity to transfer genes. these dna-bin ... | 2003 | 12533712 |
| 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 ... | 2003 | 12560332 |
| 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 ... | 2003 | 12574131 |
| detection of papillomavirus-dna in mesenchymal tumour cells and not in the hyperplastic epithelium of feline sarcoids. | we examined 12 formalin-fixed paraffin-embedded feline skin tumours which had the histopathological features of fibropapillomas for the presence of papillomavirus (pv) dna using touchdown polymerase chain reaction (pcr), dna sequencing and nonradioactive in situ hybridization. nine of the tumours contained a 102-bp pcr product demonstrated using consensus pv primers that amplify a portion of the l1 gene. the nucleotide sequences are closely related, but not identical to that of ovine pv type 2, ... | 2003 | 12603685 |
| 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 ... | 2003 | 12610128 |
| requirement of e6ap and the features of human papillomavirus e6 necessary to support degradation of p53. | e6 oncoproteins from human papillomavirus type 16 (16e6) and bovine papillomavirus type 1 (be6) bind to leucine rich peptides (called charged leucine, lxxll, or signature peptides) found on target cellular proteins. be6 and 16e6 both bind the product of the ube3a gene called e6ap on a charged leucine peptide, lqell. e6ap is an e3 ubiquitin ligase that together with 16e6 interacts with p53 to target p53 degradation. although both be6 and 16e6 bind the lqell peptide of e6ap, only 16e6 acts as an a ... | 2003 | 12620801 |
| 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 ... | 2003 | 12634101 |
| 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 ... | 2003 | 12667807 |
| papillomaviruses infect cells via a clathrin-dependent pathway. | in 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 ... | 2003 | 12667809 |
| characterization of the minimal dna binding domain of the human papillomavirus e1 helicase: fluorescence anisotropy studies and characterization of a dimerization-defective mutant protein. | the e1 helicase of papillomaviruses is required for replication of the viral double-stranded dna genome, in conjunction with cellular factors. dna replication is initiated at the viral origin by the assembly of e1 monomers into oligomeric complexes that have unwinding activity. in vivo, this process is catalyzed by the viral e2 protein, which recruits e1 specifically at the origin. for bovine papillomavirus (bpv) e1 a minimal dna-binding domain (dbd) has been identified n-terminal to the enzymat ... | 2003 | 12692220 |
| 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 ... | 2003 | 12692227 |
| 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 ... | 2003 | 12692268 |
| loss of mitotic spindle checkpoint activity predisposes to chromosomal instability at early stages of fibrosarcoma development. | mice carrying the bovine papillomavirus type i genome develop dermal fibrosarcomas in a multiple step process characterized by distinctive proliferative stages. chromosomal aberrations are identified early in this tumorigenic pathway, however, the mechanism that originates them is unknown. using a functional assay, we investigated the status of the mitotic spindle cell cycle checkpoint (msccc) that regulates the metaphase to anaphase transition, in cells representing different stages of fibrosar ... | 2003 | 12734433 |
| 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 ... | 2003 | 12749834 |
| 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 ... | 2003 | 12756294 |
| codon optimization of the hpv-16 e5 gene enhances protein expression. | the human papillomavirus type 16 (hpv-16) e5 protein is an 83-amino-acid, hydrophobic polypeptide that has been localized to intracellular membranes when overexpressed in cos-1 cells. while the hpv-16 e5 protein appears to modulate endosomal ph and signal transduction pathways, genetic analysis of its biological activities has been hampered by low (usually nondetectable) levels of expression in stable cell lines. sequence analysis of the native hpv-16 e5 gene revealed that infrequent-use codons ... | 2003 | 12832208 |
| 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 ... | 1999 | 12840887 |
| 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 ... | 2003 | 12867421 |
| cutaneous fibropapilloma in a mountain lion (felis concolor). | a 12-yr-old mountain lion (felis concolor) developed a 0.5-cm3 raised nonpigmented and nonulcerated mass between the lip and the nasal planum. the tumor was surgically removed and diagnosed histologically as a fibropapilloma. the tumor recurred 1 yr later, at which time it was again excised, and the diagnosis was reconfirmed by biopsy. frozen tissue from the second excision was submitted for polymerase chain reaction testing for papillomavirus. the 176-base pair polymerase chain reaction product ... | 2003 | 12885136 |
| 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 ... | 2003 | 12921714 |
| quercetin elevates p27(kip1) and arrests both primary and hpv16 e6/e7 transformed human keratinocytes in g1. | our previous work with primary bovine fibroblasts demonstrated that quercetin, a potent mutagen found in high levels in bracken fern (pteridium aquilinum), arrested cells in g1 and g2/m, in correlation with p53 activation. the expression of bovine papillomavirus type 4 (bpv-4) e7 overcame this arrest and lead to the development of tumorigenic cells lines (beniston et al., 2001). given the possible link between papillomavirus infection, bracken fern in the diet and cancer of the upper gastrointes ... | 2003 | 12934110 |