| t cell responses to bpv-4 e7 during infection and mapping of t cell epitopes. | vaccination of cattle with the recombinant e7 protein of bovine papillomavirus type 4 (bpv-4) prior to bpv-4 infection has been shown to retard development of papillomas and accelerate their regression. to understand the mechanism of regression we have measured proliferation of peripheral blood mononuclear cells (pbm) to e7 in vitro during the course of bpv-4 infection in both vaccinated and nonvaccinated cattle. in vaccinated cattle, t cells specific for e7 could be detected at high levels shor ... | 1995 | 7530395 |
| association of serum immunoglobulin g antibodies against human papillomavirus type 16 capsids with anal epidermoid carcinoma. | anal epidermoid carcinoma is a relatively rare tumor, but its incidence has been increasing rapidly during the past few years. genetic material from the major oncogenic types of human papillomavirus (hpv), types 16 and 18, has regularly been demonstrated in a substantial proportion of anal cancers, suggesting an etiologic role of hpv infection. recently, serum antibodies against hpv type 16 capsids were shown to be a serologic measure of hpv16 infection. | 1995 | 7532227 |
| human papillomavirus type 16 capsids expose multiple type-restricted and type-common antigenic epitopes. | the study of viral infectivity and detection of viral capsid antigens of the major cervical cancer-associated human papillomavirus (hpv) type, hpv-16, requires knowledge of which epitopes are exposed in clinical specimens of infected tissue or on intact capsids. to define the antigenic epitopes of hpv-16, antisera to 66 overlapping synthetic peptides corresponding to the hpv-16 capsid proteins l1 and l2 and to seven peptide analogues were tested in immunoperoxidase stainings of consecutive secti ... | 1995 | 7537325 |
| papillomavirus l1 capsids agglutinate mouse erythrocytes through a proteinaceous receptor. | virus-like particles (vlps) composed of l1 derived from bovine papillomavirus type 1 (bpv-1), several human papillomavirus types, or cottontail rabbit papillomavirus (crpv) agglutinated mouse but not human or rat erythrocytes. treatment of mouse erythrocytes with trypsin prevented hemagglutination (ha) by bpv-1. sera from rabbits immunized with native crpv vlps, which protect against experimental crpv infection, exhibited high titers of antibodies that inhibited crpv vlp ha activity, while sera ... | 1995 | 7541848 |
| induction of neutralizing antibodies to papillomaviruses by anti-idiotypic antibodies. | anti-idiotypic antibodies (anti-ids) were generated against three mouse monoclonal antibodies (mabs) which neutralized three different papillomaviruses. the neutralizing mabs (n-mabs) were generated against infectious human papillomavirus type 11 (hpv-11), cottontail rabbit papillomavirus (crpv), and bovine papillomavirus type 1 (bpv-1), and all recognized surface conformational epitopes that were lost upon denaturation of the virions. the polyclonal anti-ids were screened in an elisa using a pa ... | 1995 | 7542415 |
| serum igg, igm, and iga reactivity to human papillomavirus types 11 and 6 virus-like particles in different gynecologic patient groups. | serum samples from several groups of patients attending a gynecology clinic were analyzed by elisa for specific antibodies recognizing surface epitopes on intact human papillomavirus (hpv) types 6 and 11 l1 virus-like particles (vlps) that were synthesized in vitro. in these samples, positive igg and igm reactivities to hpv-11 l1 vlps were, respectively, 12% and 6% for 87 controls, 46% and 67% for 79 condyloma patients, 30% and 64% for 72 cervical intraepithelial neoplasia patients, 16% and 19% ... | 1995 | 7542685 |
| mutational analysis of the interaction between the bovine papillomavirus e5 transforming protein and the endogenous beta receptor for platelet-derived growth factor in mouse c127 cells. | the bovine papillomavirus e5 protein is a 44-amino-acid membrane-associated protein that forms a stable complex with the endogenous platelet-derived growth factor (pdgf) beta receptor in rodent and bovine fibroblasts, resulting in sustained receptor activation and cell transformation. we report here that high-level expression of the e5 protein caused a reduction in the level of the mature form of the pdgf beta receptor in acutely and stably transformed mouse c127 cells. to explore in more detail ... | 1995 | 7543592 |
| vaccination of cattle with the n-terminus of l2 is necessary and sufficient for preventing infection by bovine papillomavirus-4. | we have previously shown that cattle vaccinated with l2, the minor structural protein of bovine papillomavirus-4 (bpv-4), do not develop alimentary papillomas upon challenge with bpv-4. analysis of the b and t cell response in l2-vaccinated animals showed that the majority of the response was directed against the n-terminus and c-terminus of l2 with little response against the middle portion. cattle were vaccinated with the n-terminus or the c-terminus of l2. the animals vaccinated with the n-te ... | 1995 | 7544045 |
| organization of the major and minor capsid proteins in human papillomavirus type 33 virus-like particles. | the organization of the major (l1) and minor (l2) proteins in the human papillomavirus capsid is still largely unknown. in this study we analysed the disulphide bonding between l1 proteins and the association of l2 proteins with capsomers using virus-like particles obtained in insect cells by co-expression of the l1 and l2 genes of human papillomavirus type 33. about 50% of the l1 protein molecules in these particles (1.29 g/cm3) formed disulphide-bonded trimers. reduction of the intermolecular ... | 1995 | 7561785 |
| induced regression of bovine papillomas by intralesional immunotherapy. | it has long been assumed that papilloma regression is mediated by immunological mechanisms which are probably cellular in nature. the potentiation of these responses may alter the course of papilloma progression. certain strains of the bacterium corynebacterium parvum (propionibacterium acnes) have been shown to augment cellular immune mechanisms by increasing both macrophage and natural killer cell activity. this study involves the use of naturally occurring bovine papillomas to investigate the ... | 1994 | 7584507 |
| association of serum antibodies against defined epitopes of human papillomavirus l1, e2, and e7 antigens and of hpv dna with incident cervical cancer. | in order to provide a large-scale evaluation of the association with cervical cancer of antibodies against human papillomavirus (hpv) antigens, sera from 233 patients with primary, untreated cervical cancer and from 157 healthy age- and sex-matched blood donors were analyzed for igg and iga antibodies against hpv-derived peptide antigens and against bovine papillomavirus. several serological responses were strongly associated with cervical cancer, notably the igg response against the hpv 16 epit ... | 1995 | 7585724 |
| the functions of human papillomavirus type 11 e1, e2, and e2c proteins in cell-free dna replication. | we examined the functions of human papillomavirus type 11 (hpv-11) e1 and e2 proteins purified from sf9 cells infected with recombinant baculoviruses in cell-free hpv-11 origin (ori) replication. the e1 protein binds specifically to a wild type but not to a mutated sequence in the ori spanning nucleotide position 1. it also has a relatively strong affinity for nonspecific dna. a neutralizing antiserum directed against the amino-terminal one-third of the e1 protein totally abolishes initiation an ... | 1995 | 7592989 |
| e5 oncoprotein retained in the endoplasmic reticulum/cis golgi still induces pdgf receptor autophosphorylation but does not transform cells. | the e5 oncoprotein encoded by bovine papillomavirus type 1 is a homodimeric, hydrophobic polypeptide which is localized predominantly in golgi membranes and which transforms several cell types apparently by inducing tyrosine phosphorylation of the platelet-derived growth factor receptor (pdgf-r). while the precise mechanism of receptor activation is unknown, e5 associates with several cellular proteins, including pdgf-r and the 16k v-atpase protein, and induces the preferential phosphorylation o ... | 1995 | 7621820 |
| interaction of papillomavirus e6 oncoproteins with a putative calcium-binding protein. | human papillomaviruses (hpvs) are associated with the majority of cervical cancers and encode a transforming protein, e6, that interacts with the tumor suppressor protein p53. because e6 has p53-independent transforming activity, the yeast two-hybrid system was used to search for other e6-binding proteins. one such protein, e6bp, interacted with cancer-associated hpv e6 and with bovine papillomavirus type 1 (bpv-1) e6. the transforming activity of bpv-1 e6 mutants correlated with their e6bp-bind ... | 1995 | 7624774 |
| sequence similarities between latent membrane protein lmp-1 of epstein-barr virus, integral membrane protein p12i of human t cell leukemia/lymphotropic virus type 1, e5 transformation protein of bovine papillomavirus, and the transmembrane proteins of slowly transforming retroviruses. | | 1995 | 7632458 |
| the synergism between bovine papillomavirus type 4 and quercetin is dependent on the timing of exposure. | exposure to the flavonoid quercetin and transfection with bovine papillomavirus type 4 (bpv-4) dna lead to oncogenic transformation of primary bovine cells. here we show that the synergism between quercetin and bpv-4 (or its e7 oncogene) is stronger the shorter the interval between the two treatments. quercetin immortalizes transformed cells, confers anchorage-independent growth and induces tumorigenicity in cells transfected only with the e7 oncogene. | 1995 | 7634432 |
| mapping of the intermolecular association of human t cell leukaemia/lymphotropic virus type i p12i and the vacuolar h+-atpase 16 kda subunit protein. | the p12i protein, a small hydrophobic protein encoded by the human t cell leukaemia/lymphotropic virus type i px region, contains a proline-rich region located between two putative transmembrane (tm) domains. the p12i protein is associated with cellular endomembranes, and physically binds to the 16 kda subunit of the vacuolar h+-atpase proton pump. to investigate the nature of the 16 kda and p12i interaction and to determine the oncogenic domain of p12i, we constructed p12i mutant proteins in wh ... | 1995 | 7636472 |
| failure of the bovine papillomavirus to transform mouse embryo fibroblasts with a targeted disruption of the insulin-like growth factor i receptor genes. | mouse embryo cells with a targeted disruption of the insulin-like growth factor i receptor (igf-ir) genes (r- cells) are refractory to transformation by the simian virus 40 large t antigen and/or an activated and overexpressed ras, both of which readily transform cells from wild-type littermate embryos and other 3t3-like cells. r- cells are also refractory to transformation induced by overexpressed epidermal growth factor receptor and platelet-derived growth factor receptor beta. since the plate ... | 1995 | 7636972 |
| domains of the bpv-1 e1 replication protein required for origin-specific dna binding and interaction with the e2 transactivator. | the viral e1 and e2 proteins are required for replication of bovine papillomavirus type 1 dna. both proteins bind as a complex to the replication origin, which consists of an e1 binding site flanked on either side by e2 binding sites. the e1 protein has properties common to replication initiator proteins such as sequence-specific origin binding and dna helicase activities. the e2 protein is a transcriptional transactivator that forms a complex with the e1 protein and enhances binding of e1 to th ... | 1995 | 7645243 |
| transitional cell carcinoma of the bladder: low incidence of human papillomavirus dna detected by the polymerase chain reaction and in situ hybridization. | viral studies on mammalian urothelium have shown an association between the bovine papillomavirus and cancer of the bladder in cattle. however, the evidence for human papillomavirus (hpv) involvement in urinary bladder in man is less clear. the aim of this study was to investigate the association between hpv dna and transitional cell carcinoma of the bladder, using the highly sensitive polymerase chain reaction (pcr) and non-isotopic dna in situ hybridization of formalin-fixed paraffin-embedded ... | 1995 | 7665148 |
| both viral e2 protein and the cellular factor pebp2 regulate transcription via e2 consensus sites within the bovine papillomavirus type 4 long control region. | the bovine papillomavirus type 4 (bpv4) long control region (lcr) contains three consensus binding sites, e2(1), e2(2), and e2(3) (accn6ggt), for the viral e2 transcription factor and a fourth degenerate site, de2 (atcn6ggt), which lies 3 bp upstream of e2(3). the e2(2) site was found to bind the cellular transcription factor pebp2, and mutations at this site reduced basal promoter activity by as much as 60%, indicating an important role for pebp2 in lcr function. mutation of the e2(3) or de2 si ... | 1995 | 7666508 |
| bovine papillomavirus type 1 e2 transcriptional regulators directly bind two cellular transcription factors, tfiid and tfiib. | the bovine papillomavirus type 1 (bpv-1) e2 translational open reading frame encodes three proteins that regulate viral transcription and dna replication: the e2 transcriptional activator (e2ta), the e2 transcriptional repressor (e2tr) and the e8/e2 transcriptional repressor (e8/e2tr). e2ta is a strong activator of papillomaviral promoters and is required for viral dna replication. e2tr and e8/e2tr inhibit the activities of e2ta but also possess weak transactivational properties of their own. tw ... | 1995 | 7666533 |
| mutational analysis of the beta-type platelet-derived growth factor receptor defines the site of interaction with the bovine papillomavirus type 1 e5 transforming protein. | the e5 polypeptide of bovine papillomavirus type 1 is a small membrane-bound protein which induces the transformation of immortalized fibroblasts, apparently via the formation of a ternary complex with the platelet-derived growth factor receptor (pdgfr) and the 16-kda v-atpase protein. this interaction seems to be mediated, at least in part, by their respective transmembrane domains. e5 also cooperates with transfected beta pdgfr to induce interleukin-3 (il-3)-independent growth of a mouse myelo ... | 1995 | 7666552 |
| mutational analysis of the 18-base-pair inverted repeat element at the bovine papillomavirus origin of replication: identification of critical sequences for e1 binding and in vivo replication. | replication of bovine papillomavirus requires two viral proteins, e1 and e2-ta. previously we demonstrated that sequences within an imperfect 18-bp inverted repeat (ir) element were sufficient to confer specific binding of the e1 protein to the origin region (s. e. holt, g. schuller, and v. g. wilson, j. virol. 68:1094-1102, 1994). to identify critical nucleotides for e1 binding and origin function, a series of individual point mutations was constructed at each nucleotide position in the 18-bp i ... | 1995 | 7666554 |
| differentiation-specific alternative splicing of bovine papillomavirus late mrnas. | activation of the late promoter (pl) of bovine papillomavirus type 1 (bpv-1) is dependent on the differentiation state of keratinocytes and occurs in the upper layers of the bovine fibropapilloma. in this study, we show by in situ hybridization that a differentiation-specific pattern of bpv-1 late rna splicing is also seen in the fibropapilloma. rnas containing the 7385/3605 and 3764/5609 splice junctions were confined to the granular cell layer. in contrast, rnas containing the 7385/3225 splice ... | 1995 | 7666558 |
| monoclonal antibody neutralization of bpv-1. | mouse monoclonal antibodies were generated against intact infectious bpv-1 virions by methods previously described (christensen et al., 1990). elisa was used to screen for reactivities to intact and/or disrupted bpv-1, crpv and hpv-11 virions. several hybridomas were initially selected that showed antibody reactivity by elisa to both intact and disrupted bpv-1, to disrupted bpv-1 only, or to intact bpv-1 virions. one monoclonal antibody, designated b1.a1, which reacted only to intact bpv-1 was s ... | 1993 | 7686316 |
| the human papillomavirus type 6 and 16 e5 proteins are membrane-associated proteins which associate with the 16-kilodalton pore-forming protein. | the human papillomavirus (hpv) e5 proteins are predicted from dna sequence analysis to be small hydrophobic molecules, and the hpv type 6 (hpv-6) and hpv-11 e5 proteins share several structural similarities with the bovine papillomavirus type 1 (bpv-1) e5 protein. also similar to the bpv-1 e5 protein, the hpv-6 and hpv-16 e5 proteins exhibit transforming activity when assayed on nih 3t3 and c127 cells. in this study, we expressed epitope-tagged e5 proteins from both the "low-risk" hpv-6 and the ... | 1993 | 7690419 |
| bovine papillomavirus e1 protein can, by itself, efficiently drive multiple rounds of dna synthesis in vitro. | bovine papillomavirus e1 protein was found to be as efficient as the simian virus 40 large t antigen in initiating dna synthesis in a cell-free system derived from cos1 cells. multiple rounds of dna synthesis occur, initiated at the bovine papillomavirus type 1 origin. therefore, e1 functions in vitro as a lytic virus initiator. | 1995 | 7707551 |
| inactivation of papillomavirus by low concentrations of povidone-iodine. | a recent report by hermonat et al showed that nonoxynol 9 is completely inactive against bovine papillomavirus, which is very closely related to human papillomavirus. finding a vaginal microbicide active against human papillomavirus to reduce the risk of sexual transmission of human papillomavirus would be desirable. | 1995 | 7709321 |
| dna polymerase delta holoenzyme: action on single-stranded dna and on double-stranded dna in the presence of replicative dna helicases. | dna polymerase delta requires proliferating cell nuclear antigen and replication factor c to form a holoenzyme efficient in dna synthesis. we have analyzed three different aspects of calf thymus dna polymerase delta holoenzyme: (i) analysis of pausing during dna synthesis, (ii) replication of double-stranded dna in the absence of additional factors, and (iii) replication of double-stranded dna in the presence of the two known replicative dna helicases from simian virus 40 and bovine papilloma vi ... | 1995 | 7711022 |
| bovine papillomavirus type 1 e1 atpase activity does not depend on binding to dna nor to viral e2 protein. | replication of bovine papillomavirus type 1 (bpv-1) dna has been shown to require two viral proteins known to interact in a molecular complex: e2, a transcription activator, and e1, another nuclear phosphoprotein, which binds to the replication origin and for which helicase/atpase activities have previously been reported. here we characterize the bpv-1 e1 atpase activity. in contrast to seo et al. (proceedings of the national academy of sciences, usa, 90, 702-706, 1993), we were able to detect t ... | 1995 | 7730798 |
| an intact pdgf signaling pathway is required for efficient growth transformation of mouse c127 cells by the bovine papillomavirus e5 protein. | the bovine papillomavirus type 1 (bpv) e5 protein is a 44 amino acid, membrane-associated protein that induces growth transformation of cultured rodent and bovine fibroblasts. in transformed fibroblasts, the bpv e5 protein activates the endogenous platelet-derived growth factor (pdgf) beta receptor, and the introduction of the pdgf beta receptor gene into heterologous cell types normally lacking pdgf beta receptor expression permits transformation by the e5 protein. however, neither the endogeno ... | 1995 | 7731695 |
| ligand-independent activation of the platelet-derived growth factor beta receptor: requirements for bovine papillomavirus e5-induced mitogenic signaling. | the e5 protein of bovine papillomavirus type 1 binds to and activates the endogenous platelet-derived growth factor (pdgf) beta receptor in fibroblasts, resulting in cell transformation. we have developed a functional assay to test the ability of pdgf beta receptor mutants to mediate a mitogenic signal initiated by the e5 protein. lymphoid ba/f3 cells are strictly dependent on interleukin-3 for growth, but coexpression of the wild-type pdgf beta receptor and the e5 or v-sis-encoded protein gener ... | 1995 | 7739538 |
| e1 recognition sequences in the bovine papillomavirus type 1 origin of dna replication: interaction between half sites of the inverted repeats. | the e1 protein encoded by bovine papillomavirus type 1 (bpv-1) is required for viral dna replication, and it binds site specifically to an a/t-rich palindromic sequence within the viral origin of replication. the protein is targeted to this site through cooperative interactions and binding with the virus-encoded e2 protein. to explore the nature of the e1 binding site, we inserted a series of homologous dna linkers at the center of dyad symmetry within the e1 recognition palindrome. the effects ... | 1995 | 7745726 |
| immunization with viruslike particles from cottontail rabbit papillomavirus (crpv) can protect against experimental crpv infection. | we tested the ability of vaccination with virus-like particles (vlps) to protect domestic rabbits against papillomas induced by the cottontail rabbit papillomavirus (crpv). a recombinant baculovirus system that expressed only the l1 major papillomavirus structural protein or l1 plus the minor l2 protein was used in insect cells as the source of vlps. groups of 10 rabbits were immunized with native or denatured vlps from crpv or type 1 bovine papillomavirus by using freund's adjuvant. alum was us ... | 1995 | 7745754 |
| cancer mortality among workers in abattoirs and meatpacking plants: an update. | workers in abattoirs and meatpacking plants have potential for exposure to bovine leukemia virus (blv) and bovine papilloma viruses (bpv), which are oncogenic in cattle. these workers also have increased exposure to human papilloma viruses (hpv) and certain chemical carcinogens. we investigated whether such a group showed increased risk of cancers. we report mortality results after an additional 9-year follow-up of a previously studied group of 5,522 workers in abattoirs and 4,589 workers in mea ... | 1995 | 7747745 |
| the human immunodeficiency virus type 1 rev protein and the rev-responsive element counteract the effect of an inhibitory 5' splice site in a 3' untranslated region. | a 5' splice site located in a 3' untranslated region (3'utr) has been shown previously to inhibit gene expression. natural examples of inhibitory 5' splice sites have been identified in the late 3'utrs of papillomaviruses and are thought to inhibit viral late gene expression at early stages of the viral life cycle. in this study, we demonstrate that the interaction of the human immunodeficiency virus type 1 rev protein with the rev-responsive element (rre) overcomes the inhibitory effects of a 5 ... | 1995 | 7760794 |
| structure of the bpv-1 e2 dna-binding domain bound to its dna target. | the dominant transcriptional regulator of papillomaviruses is the e2 protein. in human papillomaviruses, the e2 protein regulates the expression of the e6 and e7 oncogenes. the functions of e2 are mediated subsequent to its specific interaction with a 12 base-pair palindromic dna target, the e2-bs. elucidation of the stereochemical basis of dna target selection by the e2 protein is a key step in understanding transcriptional regulation in these cancer-causing viruses. the crystal structure of th ... | 1995 | 7769463 |
| amino-terminal domains of the bovine papillomavirus type 1 e1 and e2 proteins participate in complex formation. | interaction between the e1 and e2 papillomavirus proteins appear to play an important role in viral dna replication, although the exact domains of each protein involved in this interaction have not been identified. using bovine papillomavirus type 1 (bpv-1) as a model for examining interactions between e1 and e2, we have used the two-hybrid and glutathione s-transferase (gst) fusion systems to map domains of bpv-1 e1 and e2 that interact in vivo and in vitro. in the two-hybrid system experiments ... | 1995 | 7769698 |
| infection by bovine papillomavirus and prospects for vaccination. | infection with bovine papillomavirus (bpv) results in the onset of benign proliferative lesions that usually regress spontaneously through a cell-mediated immune response. occasionally, warts persist as benign tumours or progress to squamous-cell carcinomas. vaccines that prevent or cure bpv infection provide a model for the formulation of vaccines against human papillomavirus. | 1995 | 7773594 |
| a transition in transcriptional activation by the glucocorticoid and retinoic acid receptors at the tumor stage of dermal fibrosarcoma development. | in transgenic mice harboring the bovine papillomavirus genome, fibrosarcomas arise along an experimentally accessible pathway in which normal dermal fibroblasts progress through two pre-neoplastic stages, mild and aggressive fibromatosis, followed by a final transition to the tumor stage. we found that the glucocorticoid receptor (gr) displays only modest transcriptional regulatory activity in cells derived from the three non-tumor stages, whereas it is highly active in fibrosarcoma cells. upon ... | 1995 | 7774580 |
| construction of a novel bovine papillomavirus vector without detectable transforming activity suitable for gene transfer. | bovine papillomavirus type 1 (bpv-1)-derived vectors may be useful for gene therapy because of their episomal maintenance at intermediate to high copy number and stable, high-level expression of gene products. to increase the safety of bpv-1 for human trials, the transforming early genes e5, e6, and e7 were deleted and a new vector, b45-neo, was established and its transforming potential, episomal maintenance, and cdna expression determined. deletion of e5, e6, and e7, caused a decrease of the c ... | 1995 | 7779916 |
| vaccination against cutaneous and mucosal papillomavirus in cattle. | viruses are responsible for approximately 15% of human cancer worldwide. human papillomavirus and hepatitis b virus are the recognized agents of cervical and liver cancer, respectively, which together constitute 80% of all virally induced cancers. if measures could be found to bring viral infection under control, a great proportion of human cancer would be greatly reduced. experimental vaccines are being developed against papillomavirus. in principle two different types of vaccine can be envisag ... | 1994 | 7796677 |
| genomic sequences of bovine papillomaviruses in formalin-fixed sarcoids from australian horses revealed by polymerase chain reaction. | seventy six formalin-fixed paraffin-embedded sarcoids from 62 australian horses, collected over a ten year period, were examined for the presence of genomic sequences from bovine papillomavirus 1 and 2 (bpv1, bpv2) with the polymerase chain reaction (pcr). sequences that could be amplified by primers specific for bpv1 and bpv2 were present in 56 of the 76 sarcoids (73%). a restriction site present in bpv1 and absent from bpv2 was detected in 28 of 34 amplified products that were treated with end ... | 1994 | 7801519 |
| the bovine papillomavirus 1 e2 protein contains two activation domains: one that interacts with tbp and another that functions after tbp binding. | the e2 transactivator of bovine papillomavirus type-1 is unable to activate minimal promoters in vivo that contain only e2 binding sites and a tata box. this block can be overcome by over-expression of human tata binding protein (tbp) or by the addition of either sp1 binding sites or an initiator element to the promoter, suggesting that the binding of tfiid may normally be a rate-limiting step for activation by e2. surprisingly, purified e2 and tbp bind co-operatively to dna in vitro when the si ... | 1995 | 7835344 |
| papillomavirus dna replication. | | 1994 | 7843926 |
| transcription of papillomavirus genomes. | | 1994 | 7843927 |
| transforming proteins of the papillomaviruses. | | 1994 | 7843928 |
| detection, cloning and characterisation of papillomaviral dna present in sarcoid tumours of equus asinus. | molecular investigations on 18 naturally occurring sarcoid tumors removed from donkeys identified papillomaviral dna homologous to bovine papillomavirus (bpv)-2 dna under stringent conditions, in all the samples. restriction endonuclease analysis of 15 of the tumours demonstrated papillomaviral dna similar to bpv-1 and bpv-2. the type of dna was not specific to either the site or the type of lesion. the analysis of the nucleotide base sequence of a cloned papillomaviral element from a sarcoid sh ... | 1994 | 7846835 |
| flow cytometric quantitation of c-myc and p53 proteins in bovine papillomavirus type 1-transformed primary mouse fibroblasts. | bovine papillomavirus type 1 (bpv-1)-transformed mouse fibroblast cell lines were analyzed via flow cytometry (fcm) for expression of p53 and c-myc proteins along with their dna content. in comparison to the nontransformed control cell line, significantly elevated levels of both the p53 and the c-myc protein were present in some but not all of the transformed cell lines. quantitation of p53 and c-myc proteins in cell lines containing bpv-1 dna revealed that the tumorigenic cell lines expressed h ... | 1994 | 7851159 |
| postattachment neutralization of papillomaviruses by monoclonal and polyclonal antibodies. | postattachment neutralization of papillomaviruses (pvs) was analyzed in three pv-infectivity models: (i) the bpv-1-induced focus-forming assay using c127 cells; (ii) in vitro abortive infection of rabbit rk-13 and sf1ep cells with crpv; and (iii) hpv-11-induced morphological transformation of human foreskin chips in the athymic mouse xenograft system. in each assay system, aliquots of infectious virus were added to the appropriate target cells and incubated at 37 degrees, followed at various pos ... | 1995 | 7871722 |
| a novel method for selective isotope labeling of bacterially expressed proteins. | a novel method for isotope labeling in selected amino acids is presented for use with the t7 rna polymerase system. the protocol is illustrated with the dna-binding domain from the e2 protein of bovine papillomavirus, bpv-1. on addition of rifampicin, protein expression occurs exclusively from the gene controlled by the t7 promoter. since the bacteria are now dedicated to the production of e2 protein, labeling with specific amino acids is efficiently performed. for example, 10 mg/l of 15n-labele ... | 1995 | 7881274 |
| bovine papillomavirus e1 protein binds specifically dna polymerase alpha but not replication protein a. | extracts prepared from either mouse cells or monkey cells were examined for the ability to support in vitro bovine papillomavirus type 1 (bpv1) dna replication, and they were used in parallel as a source of host replication proteins for affinity chromatography. dna synthesis exhibited an absolute requirement for bpv1 e1 protein. in contrast to previous observations, we found that low levels of e1 were highly efficient in initiating dna replication in the absence of the bpv1 transcription factor ... | 1995 | 7884880 |
| vacuolar h(+)-atpase mutants transform cells and define a binding site for the papillomavirus e5 oncoprotein. | the 16k subunit of the vacuolar h(+)-atpase binds specifically to the bovine (bpv) and human (hpv) papillomavirus e5 oncoproteins, and it has been suggested that this interaction may contribute to cell transformation (goldstein, d. j., and schlegel, r. (1990) embo j. 9, 137-146; goldstein, d. j., finbow, m. e., andresson, t., mclean, p., smith, k., bubb, v. j., and schlegel, r. (1991) nature 352, 347-349; conrad, m., bubb, v. j., and schlegel, r. (1993) j. virol. 67, 6170-6178; goldstein, d. j., ... | 1995 | 7896830 |
| identification of human papillomavirus seroconversions. | the temporal relationship between primary genital human papillomavirus (hpv) infections and the induction of antibodies against viral antigens has not been established. in order to address this question we studied a cohort of 110 women and 48 men with multiple heterosexual partners, who were followed for 220 person-years during which they made 583 visits to the sexually transmitted diseases clinic of the amsterdam public health service. at each visit spatula or brush samples from multiple anogen ... | 1995 | 7897345 |
| hierarchy of polyadenylation site usage by bovine papillomavirus in transformed mouse cells. | the great majority of viral mrnas in mouse c127 cells transformed by bovine papillomavirus type 1 (bpv) have a common 3' end at the early polyadenylation site which is 23 nucleotides (nt) downstream of a canonical poly(a) consensus signal. twenty percent of bpv mrna from productively infected cells bypasses the early polyadenylation site and uses the late polyadenylation site approximately 3,000 nt downstream. to inactivate the bpv early polyadenylation site, the early poly(a) consensus signal w ... | 1993 | 7901430 |
| the e5 protein of hpv-6, but not hpv-16, associates efficiently with cellular growth factor receptors. | the transforming activity of the prototype e5 protein of bovine papillomavirus type 1 (bpv-1) is associated with its binding to, and activation of, both the platelet-derived growth factor (pdgf) and epidermal growth factor (egf) receptors. the e5 proteins of human papillomavirus types 6 and 16 (hpv-6, hpv-16) also transform rodent cells in the presence of the egf receptor. in this study we examined whether epitope-tagged hpv e5 proteins could associate with three different tyrosine kinase-contai ... | 1994 | 7909971 |
| the bovine papillomavirus type 1 genome contains multiple loci of static dna bending, but bends are absent from the functional origin of replication. | twenty-four overlapping restriction fragments spanning the entire bovine papillomavirus type 1 (bpv-1) genome were analyzed by electrophoresis to determine the extent of static dna bending in the bpv-1 genome. thirteen of 24 fragments contained static bends. based on known locations of previously mapped bend loci and the overlapping pattern of these 13 fragments, we estimate that there are 8-11 distinct static bend loci in the bpv-1 genome. the bend loci were not uniformly distributed on the gen ... | 1994 | 7909975 |
| regulation of dna synthesis in division-arrested mouse c127 cells permissive for bovine papillomavirus dna amplification. | spontaneous amplification of bovine papillomavirus type 1 dna occurs following a prolonged period of serum starvation of wild-type virus-transformed c127 cell lines and is associated with abundant viral e2 protein synthesis and a concomitant induction of viral oncogene (e5 and e6) expression. we show here that a subpopulation of the permissive cells incorporate bromo-deoxyuridine under conditions of cell growth arrest (serum starvation), whereas dna synthesis is suppressed in the resting populat ... | 1994 | 7911533 |
| bovine papillomavirus e1 protein affects the host cell cycle phase fractions. | c127 murine fibroblast cells were electroporated with a bovine papillomavirus e1 protein expression vector and examined by flow cytometry. e1 expressing cells (e1+) within the total cell population were distinguished from nonexpressing cells (e1-) by immunofluorescent staining with anti-e1 serum and a fluorescein-conjugated second antibody. under conditions of saturation with the first and second antibodies, the specific green fluorescence reflected the level of intracellular e1 protein. simulta ... | 1994 | 7924681 |
| interaction of papillomaviruses with the cell surface. | to initiate an investigation of the initial step in papillomavirus infection, we have examined the interaction of bovine papillomavirus type 1 (bpv) virions with c127 cells by two assays, binding of radioiodinated bpv virions to cell monolayers and bpv-induced focal transformation. under physiological conditions, the labeled virions bound to the cell surface in a dose-dependent manner within 1 h. antibody studies indicated that the interaction was specific and related to infectivity: polyclonal ... | 1994 | 7933109 |
| e1 protein of human papillomavirus type 1a is sufficient for initiation of viral dna replication. | previous studies on transient replication of papillomaviruses have shown an absolute requirement for the viral e1 and e2 proteins in dna replication. here we demonstrate that for human papillomavirus type 1a (hpv-1a) dna, the e1 protein alone is sufficient for in vivo replication of plasmids containing the viral origin of replication. replication was origin-specific and required the presence of a dna sequence containing a putative e1 binding site, but the e2 binding sites were dispensable. in th ... | 1994 | 7937813 |
| [morphologic and molecular biologic studies of the etiology of equine sarcoid]. | from 932 equine skin lesions 421 were diagnosed as sarcoids (about 45%). the most common locations were the ventral body regions, head, neck and sites of thin skin. most often the fibroblastic type, less frequently the mixed type and most infrequent the verrucous type of sarcoid were diagnosed. detection of bpv-dna was performed by polymerase chain reaction (pcr) using an oligonucleotide primer pair located in the e5-open reading frame. dna of bpv 1 and bpv 2 could be differentiated by digestion ... | 1994 | 7940516 |
| the role of the e1 and e2 proteins in the replication of human papillomavirus type 31b. | using transient assays, the cis and trans requirements for human papillomavirus type 31b (hpv-31b) replication in transformed and primary keratinocytes have been determined. we demonstrate that expression of both the e1 and e2 open reading frames are necessary and sufficient for replication of a plasmid construct containing a genomic 291-bp fragment in both cell types. the roles of the e1 and e2 proteins in replication were further examined by overexpressing the gene products in a glutathione-s- ... | 1994 | 7941349 |
| studies on the frequency and associations of equine leucocyte antigens in sarcoid and summer dermatitis. | the equine leucocyte antigen (ela) types and the clinical diagnosis for equine sarcoid and summer dermatitis were evaluated in 2026 horses representing five breeds. data were analysed in unrelated animals and in family material. in the case of equine sarcoid, a strong association was observed between the ela class ii dw13 antigen and its effect on swiss (cp < 0.001), french (cp < 0.0001) and irish (cp < 0.01) warmblood horses. the class i antigen a3 occurred more frequently in sarcoid-affected f ... | 1994 | 7943987 |
| site-specific dna-binding proteins important for replication and transcription have multiple activities. | | 1993 | 7956054 |
| site-specific initiation of dna replication in metazoan chromosomes and the role of nuclear organization. | we have asked whether or not xenopus eggs or egg extracts, which have previously been shown to replicate essentially any dna molecule, will preferentially utilize a known mammalian obr. our results reveal that xenopus egg extracts can preferentially initiate dna replication at sites chosen in vivo by the hamster cell, provided that the dna substrate is presented to the extract in the form of a nucleus rather than bare dna. thus, site-specific initiation of dna replication in metazoan cell chromo ... | 1993 | 7956062 |
| characterization of the human papillomavirus e2 protein: evidence of trans-activation and trans-repression in cervical keratinocytes. | the major regulator of papillomavirus transcription is encoded by the viral e2 gene. the e2 gene has been well characterized in bovine papillomavirus (bpv) where it encodes at least three different polypeptides which differentially affect viral gene expression. in human papillomaviruses (hpvs) the e2 gene product is much less well characterized. in this study we have analysed the mechanism of action of the hpv-16, hpv-18 and bpv-1 e2 proteins in cervical keratinocytes. we show that the full leng ... | 1994 | 7957111 |
| an element binding a c/ebp-related transcription factor contributes to negative regulation of the bovine papillomavirus type 4 long control region. | deletion of the nr2 element of the long control region (lcr) of bovine papillomavirus type 4 (bpv-4) was observed previously to lead to a fivefold increase in enhancer activity of a subfragment of the lcr. further characterization of this element indicates that mutations in nr2 lead to increased enhancer activity in both mouse ct3 fibroblasts and in a transformed bovine epithelial cell line derived from an alimentary canal papilloma/in situ carcinoma, but not in primary bovine keratinocytes. sin ... | 1994 | 7964614 |
| the genomes of the animal papillomaviruses european elk papillomavirus, deer papillomavirus, and reindeer papillomavirus contain a novel transforming gene (e9) near the early polyadenylation site. | we report that the genomes of reindeer papillomavirus (rpv), european elk papillomavirus (eepv), and deer papillomavirus (dpv) contain a short conserved translational open reading frame (orf), e9, which is located between the e5 orf and the early polyadenylation site. in rpv, dpv, and eepv, e9 orfs have the potential to encode extremely hydrophobic polypeptides of approximately 40 amino acids. in mouse c127 cells transformed by eepv and rpv, there exists a unique, abundant mrna species of approx ... | 1994 | 7966628 |
| negative regulation of the bovine papillomavirus e5, e6, and e7 oncogenes by the viral e1 and e2 genes. | papillomaviruses induce benign squamous epithelial lesions that infrequently are associated with uncontrolled growth or malignant conversion. the virus-encoded oncogenes are clearly under negative regulation since papillomaviruses can latently infect cells and since different levels of viral oncogene expression are seen within the layers of differentiating infected epitheliomas. we used bovine papillomavirus type 1 (bpv-1) to investigate the mechanisms involved in the negative regulation of tran ... | 1995 | 7983735 |
| [immunotherapy of tumors in agricultural domestic animals]. | | 1994 | 7992305 |
| bovine cutaneous papillomas associated with bovine papillomavirus type 5. | squamous papillomas obtained from bovine facial skin yielded viral dna indistinguishable from that of bovine papillomavirus type 5. it was separated from recognised bovine papillomaviruses by its restriction endonuclease pattern and hybridization tests with dna. | 1994 | 7998842 |
| replication of bovine papillomavirus type 1 origin-containing dna in crude extracts and with purified proteins. | the in vitro replication of dna containing the bovine papillomavirus (bpv-1) origin has been carried out with cell-free extracts from mouse fm3a and human hela cells. dna synthesis required the e1 protein, the minimal origin of replication (nucleotides 7911-22 of the bpv-1 genome), and, at low levels of fm3a extract, the addition of the human single-stranded dna-binding protein (also called rp-a or rf-a). the e2 protein was not absolutely required, but could stimulate dna synthesis at low levels ... | 1994 | 8006013 |
| sequences homologous to 5' splice sites are required for the inhibitory activity of papillomavirus late 3' untranslated regions. | expression of bovine papillomavirus type 1 (bpv-1) late genes is limited to terminally differentiated keratinocytes in an infected epithelium. we have previously shown that although the bpv-1 late polyadenylation site is functional in nonpermissive cells, a 53-nucleotide (nt) fragment of the late 3' untranslated region acts posttranscriptionally to reduce polyadenylated cytoplasmic rna levels. this 53-nt fragment does not appear to function by destabilizing polyadenylated cytoplasmic rna (p. a. ... | 1994 | 8035806 |
| acidic transcription factors alleviate nucleosome-mediated repression of dna replication of bovine papillomavirus type 1. | the papillomavirus e2 transcription factor is directly involved in viral dna replication. previous studies have shown that e2 interacts with both the viral e1 helicase and cellular replication proteins, and thus it may facilitate their targeting to the origin of replication. we demonstrate here that e1-mediated replication of bovine papillomavirus type 1 is repressed by nucleosomal assembly. the e2 protein counteracts this repression, and such activation requires the e2-binding sites adjacent to ... | 1994 | 8041744 |
| [recombinant murine cell lines, transformed by various vectors based on bovine type 1 papillomavirus and expressing human tissue plasminogen activator. ii. analysis of cell lines, producing recombinant tissue plasminogen activator]. | we have characterized a number of recombinant cell lines established with bpv1 and lx1 (containing duplication of lcr-e6-e7 sequence) vectors on the basis of c127 cells. it had been shown that lx1 based vectors possess the higher number of intracellular copies than analogous vectors on the basis of wtbpv, and most part of them is integrated into the host genome. using various concentrations of heavy metal salts we have developed the optimized procedure for induction of recombinant tpa synthesis ... | 1994 | 8052253 |
| experimental reproduction of the papilloma-carcinoma complex of the alimentary canal in cattle. | bovine papillomavirus type 4 (bpv-4) is the aetiological agent of epithelial papillomas of the upper alimentary canal in cattle. these benign tumours can become a focus for transformation to squamous cell carcinomas in animals feeding on bracken fern. strong epidemiological evidence suggests that the progression to malignancy is due to the interplay between bpv-4 and mutagenic and immunosuppressing chemicals present in the fern. the carcinomas of the upper alimentary canal are often accompanied ... | 1994 | 8055638 |
| mutation of the bovine papillomavirus e5 oncoprotein at amino acid 17 generates both high- and low-transforming variants. | the e5 transforming protein of bovine papillomavirus type 1 is a 44-amino-acid, hydrophobic protein which localizes predominantly to golgi membranes. the e5 transmembrane domain contains a highly conserved glutamine residue at position 17 which, from previous limited mutagenic analysis, appeared essential for transforming activity. in order to determine the specific amino acid requirements at this position, we constructed a series of substitution mutants, representing all classes of amino acids, ... | 1994 | 8057494 |
| cloning and sequencing of the l1 gene of canine oral papillomavirus. | canine oral papillomavirus (copv) dna was isolated from two different sources. one of these dnas was molecularly cloned and its physical map was determined. hybridization analyses using subgenomic fragments of bovine papillomavirus type 1 (bpv-1) and human papillomavirus type 16 (hpv16) as probes revealed that the cloned copv shared moderate homology within the e1 and l1 regions of bpv-1 and hpv16, whereas homology in other regions of bpv-1 and hpv16 was low. the putative l1 gene of copv was seq ... | 1994 | 8076829 |
| genetically defined nuclear localization signal sequence of bovine papillomavirus e1 protein is necessary and sufficient for the nuclear localization of e1-beta-galactosidase fusion proteins. | the 605 amino acid e1 protein of bovine papillomavirus type 1 (bpv-1) is a multifunctional nuclear protein required for viral dna replication. a nuclear localization signal (nls) sequence was previously defined by point mutations in three short adjacent clusters of basic amino acids located in the amino-terminal region of the e1 protein. in this study, we used a fusion protein approach to evaluate the contribution of other regions of the e1 protein to nuclear transport. the nearly full-length e1 ... | 1994 | 8077949 |
| the cellular dna polymerase alpha-primase is required for papillomavirus dna replication and associates with the viral e1 helicase. | persistent infection by papillomaviruses involves the maintenance of viral dna as a nuclear plasmid, the replication of which requires host dna polymerases. the role of the cellular dna polymerase alpha-primase holoenzyme was probed by using soluble extracts from rodent cells that replicate bovine papilloma virus 1 and human papilloma virus 6b dna in the presence of the viral e1 helicase and the e2 transcription factor. monoclonal antibodies directed against the catalytic 180-kda subunit of poly ... | 1994 | 8078945 |
| trans activation by the full-length e2 proteins of human papillomavirus type 16 and bovine papillomavirus type 1 in vitro and in vivo: cooperation with activation domains of cellular transcription factors. | papillomaviral e2 genes encode proteins that regulate viral transcription. while the full-length bovine papillomavirus type 1 (bpv-1) e2 peptide is a strong trans activator, the homologous full-length e2 product of human papillomavirus type 16 (hpv-16) appeared to vary in function in previous studies. here we show that when expressed from comparable constructs, the full-length e2 products of hpv-16 and bpv-1 trans activate a simple e2- and sp1-dependent promoter up to approximately 100-fold in h ... | 1994 | 8083999 |
| role of transcriptional repressors in transformation by bovine papillomavirus type 1. | transformation of rodent cells by bovine papillomavirus type 1 (bpv-1) has been shown to require the direct contribution of the viral oncogenes encoded by the e5, e6, and e7 translational open reading frames (orfs). it is also known that the viral e1 and e2 orfs contribute indirectly to cellular transformation through their transcriptional modulation of these viral oncogenes. a mutant bpv-1 disrupted in two of the proteins encoded by the e2 orf, the e2 transcriptional repressors, has a complex t ... | 1994 | 8084016 |
| induction of structural changes in the bovine papillomavirus type 1 origin of replication by the viral e1 and e2 proteins. | chemical and enzymatic probing techniques were used to examine the interaction of the bovine papillomavirus type 1 e1 and e2 proteins with the viral origin of replication (ori). e1 was found to generate significant distortions to the structure of ori, as assayed by kmno4 oxidation of dna. the primary site of ori distortion was located within and adjacent to the at-element of the core replicator sequence, although a number of minor structural transitions were also detected. the induction of these ... | 1994 | 8090734 |
| the bovine papillomavirus e2 protein modulates the assembly of but is not stably maintained in a replication-competent multimeric e1-replication origin complex. | initiation of bovine papillomavirus (bpv) dna synthesis in vivo and in vitro depends on the interaction of the viral initiator protein e1 with the replication origin (ori+ dna). the viral e2 protein assists this interaction, resulting in a cooperative assembly of both proteins on the replication origin. using gel mobility-shift experiments, we demonstrate that in the presence of both e1 and e2 proteins two classes of ori+ dna complexes were formed: complex 1 (c1) and complex 2 (c2). formation of ... | 1994 | 8090740 |
| the bovine papillomavirus e1 protein alters the host cell cycle and growth properties. | a stable e1-expressing cell line, ce1, was developed to investigate the effect of bovine papillomavirus e1 protein on host cell growth. expression of e1 in ce1 cells is under control of the dexamethasone-inducible mouse mammary tumor virus ltr promoter. flow cytometry was used to determine the intracellular levels of e1 in ce1 cells in parallel with cell cycle distributions and cell growth parameters. ce1 cells expressed a basal level of e1 that was increased following exposure to increasing con ... | 1994 | 8091648 |
| the bovine papilloma virus e1 protein has atpase activity essential to viral dna replication and efficient transformation in cells. | the bovine papilloma virus (bpv) e1 protein essential to viral dna replication has recently been shown to associate via direct protein-dna interactions with the viral origin of replication and to be an atp-dependent helicase. we show here that in accordance with the latter function, the e1 gene product has intrinsic atpase activity. mutations placed throughout the nucleotide binding consensus element abolish the atpase activity of e1 and render bpv genomes harboring such mutations defective for ... | 1994 | 8091670 |
| segregation properties of bovine papillomaviral plasmid dna. | essentially complete segregation of replication-competent bpv-1 plasmid dna species was observed in daughter subclones derived from primary co-transformed c127 cell lines. thus, whereas primary co-transformants retained both of two distinguishable co-transfected plasmid species, subcloning experiments revealed that morphologically transformed daughter subclones derived from such co-transformed cell lines contained only one species of viral plasmid dna. similar results were obtained with each of ... | 1994 | 8107134 |
| 1h nmr studies of the mercuric ion binding protein merp: sequential assignment, secondary structure and global fold of oxidized merp. | the oxidized form of the mercuric ion binding protein merp has been studied by two-dimensional nmr. merp, which is a periplasmic water-soluble protein with 72 amino acids, is involved in the detoxification of mercuric ions in bacteria with resistance against mercury. the mercuric ions in the periplasmic space are first scavenged by the merp protein, then transported into the cytoplasm by the membrane-bound transport protein mert, and finally reduced to elementary (nontoxic) mercury by the enzyme ... | 1993 | 8111228 |
| papillomavirus contains cis-acting sequences that can suppress but not regulate origins of dna replication. | bovine papillomavirus (bpv) dna has been reported to restrict its own replication and that of the lytic simian virus 40 (sv40) origin to one initiation event per molecule per s phase, which suggests bpv dna replication as a model for cellular chromosome replication. suppression of the sv40 origin required two cis-acting bpv sequences (ncor-1 and -2) and one trans-acting bpv protein. the results presented in this paper confirm the presence of two ncor sequences in the bpv genome that can suppress ... | 1994 | 8151772 |
| activation of eukaryotic transcriptional promoters by the bovine papillomavirus e1-replication factor. | it has been suggested that the bovine papillomavirus type 1 e1 replication factor may inhibit e2-conditional gene expression from viral promoter p89. to study the possible role of the e1 protein in gene expression, hela cells were transfected with e2-conditional or e2-independent reporter plasmids and with vectors expressing the e1 and e2 open reading frames. the data show that: (i) replication factor e1 stimulates gene expression from a variety of eucaryotic transcriptional promoters; (ii) acti ... | 1993 | 8169116 |
| adeno-associated virus inhibits human papillomavirus type 16: a viral interaction implicated in cervical cancer. | human papillomavirus (hpv) infection, in particular that by hpv type 16, is positively associated with cervical/genital cancer. in contrast, human adeno-associated virus (aav) infection is negatively associated with these same cancers. aav has also been found to inhibit the oncogenic properties of a variety of dna viruses, including bovine papillomavirus type 1, a relative of hpv-16. taken together, these findings suggested the possibility that aav and hpv-16 might interact, with aav inhibiting ... | 1994 | 8174138 |
| specific interaction between the bovine papillomavirus e5 transforming protein and the beta receptor for platelet-derived growth factor in stably transformed and acutely transfected cells. | the e5 protein of bovine papillomavirus is a 44-amino-acid membrane protein which induces morphologic and tumorigenic transformation of fibroblasts. we previously showed that the e5 protein activates and forms a complex with the endogenous beta receptor for platelet-derived growth factor (pdgf) in transformed rodent fibroblasts and that the pdgf beta receptor can mediate tumorigenic transformation by the e5 protein in a heterologous cell system. other workers have identified the receptor for epi ... | 1994 | 8189497 |
| latent papillomavirus infection in cattle. | during a long term experiment designed to identify the contribution of bovine papillomavirus type 4 (bpv-4), environmental mutagens and immunosuppressants to the development of carcinomas of the upper alimentary tract of cattle, there was evidence of latent papillomavirus infection. papillomatosis-free animals, when immunosuppressed either by feeding bracken fern or by azathioprine treatment, developed skin warts containing either bpv-1 or bpv-2. skin warts appeared also in an immunocompetent an ... | 1994 | 8191003 |
| cellular transformation by a transmembrane peptide: structural requirements for the bovine papillomavirus e5 oncoprotein. | the e5 oncoprotein of bovine papillomavirus, only 44 amino acids long, occurs as a disulfide-bonded transmembrane dimer. this remarkable oncoprotein stimulates signal transduction through activation of the platelet-derived growth factor (pdgf) receptor, and e5 exhibits limited amino acid sequence similarity with pdgf. results presented here suggest that a key feature of the hydrophobic transmembrane domain is an amino acid side chain that participates in interhelical hydrogen bond formation. the ... | 1994 | 8197111 |
| vaccination against papillomavirus in cattle. | | 1994 | 8205844 |
| the bovine papillomavirus type 1 e5 transforming protein specifically binds and activates the beta-type receptor for the platelet-derived growth factor but not other related tyrosine kinase-containing receptors to induce cellular transformation. | the 44-amino-acid e5 protein of bovine papillomavirus type 1 is a highly hydrophobic protein which appears to transform cells through the activation of growth factor receptors. to investigate the specificity of e5-growth factor receptor interactions required for mitogenic signaling, we utilized a nontumorigenic, murine myeloid cell line (32d) which is strictly dependent on interleukin-3 (il-3) for sustained proliferation in culture. this il-3 dependence can be functionally substituted by the exp ... | 1994 | 8207816 |
| anomalous transforming behavior of a bovine papillomavirus type 1 mutant with an upstream promoter mutation. | we show that the previously described high-transformation phenotype of the bovine papillomavirus type 1 mutant bpv730 is manifested only in an e6-dependent cell transformation assay. the bpv730 mutation was associated with superinduction of the putative e6 promoter, p89, after cycloheximide treatment, and with reduced activity of the p3080 promoter. | 1994 | 8207842 |
| the tryptophan bridge is a critical feature of the papillomavirus e2 dna binding domain. | the papillomavirus e2 protein is a dna binding protein that regulates viral transcription and replication. e2 binds dna as a dimer. recent crystallographic data for e2 complexed to dna revealed that novel peptide structures in e2 mediated dimerization and dna binding. to identify important features of these motifs we have used limited proteolysis and urea denaturation as biochemical probes for structure, applying these techniques to e2 alone, e2 bound to dna, cross-linked products, and mutants t ... | 1993 | 8212573 |