Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| [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 |
| 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 |
| neutralization of bovine papillomavirus by antibodies to l1 and l2 capsid proteins. | we have generated four mouse monoclonal antibodies (mabs) to bovine papillomavirus virions that bound type-specific, adjacent, and conformationally dependent epitopes on the l1 major capsid protein. all four mabs were neutralizing at ratios of 1 mab molecule per 5 to 25 l1 molecules, but only three effectively blocked binding of the virus to the cell surface. therefore, antibodies can prevent papillomavirus infection by at least two mechanisms: inhibition of cell surface receptor binding and a s ... | 1994 | 7523700 |
| 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 |
| humoral immune response to the e7 protein of bovine papillomavirus type 4 and identification of b-cell epitopes. | we have previously vaccinated cattle with e7, the major transforming protein of bovine papillomavirus-4, prior to homologous virus challenge. this retarded the development of papillomas and promoted their early regression compared to control animals. to understand the mechanism for this regression, we have studied the b and t cell response in vaccinated animals and compared it to that of non-vaccinated, virus-infected animals. the b cell response is reported here. the development of e7 igg antib ... | 1994 | 7510442 |
| cell-free replication of the human papillomavirus dna with homologous viral e1 and e2 proteins and human cell extracts. | we have established the first homologous cell-free dna replication system for a papillomavirus. the replication of the human papillomavirus type 11 (hpv-11) origin was achieved by using human 293 cell extracts supplemented with the hpv-11 e1 and e2 proteins purified from insect cells infected with recombinant baculoviruses. efficient replication depends on the hpv-11 origin, the hpv-11 e1 and e2 proteins, as well as human dna polymerase alpha, delta, replication protein a, topoisomerase i, and t ... | 1994 | 7523366 |
| expression of a retinoic acid-inducible mitochondrial nd5 gene is regulated by cell-density in bovine papillomavirus dna-transformed mouse c127 cells but not in revertant cells. | prolonged treatment with 5 mum all-trans retinoic acid (ra) resulted in the disappearance of viral dna and phenotypic reversion in bovine papillomavirus (bpv) dna-transformed mouse c127 cells (int j oncol 3: 319-324, 1993). the ra-induced revertants exhibited increased resistance to bpv dna-induced cell transformation. using selective hybridization techniques, we have cloned a cdna sequence from an ra-induced revertant cell line, bf3ra10. sequencing data reveals that the cdna sequence was derive ... | 1994 | 21559589 |
| 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 |
| 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 |
| 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 |
| 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 |
| cellular factors required for papillomavirus dna replication. | in vitro replication of papillomavirus dna has been carried out with a combination of purified proteins and partially purified extracts made from human cells. dna synthesis requires the viral e1 protein and the papillomavirus origin of replication. the e2 protein stimulates dna synthesis in a binding site-independent manner. papillomavirus dna replication is also dependent on the cellular factors replication protein a, replication factor c, and proliferating-cell nuclear antigen as well as a pho ... | 1995 | 7494298 |
| 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 |
| 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 |
| transformed mouse cell lines that consist predominantly of cells maintaining bovine papilloma virus at high copy number. | rare cells that contain large amounts of bovine papilloma virus (bpv) dna have been observed in populations of bpv-transformed mouse id13 cells. the viral dna molecules in these "jackpot cells" have been thought to have switched from the controlled replication typical of latent bpv infection to the uncontrolled "runaway" prelytic replication characteristic of terminal stage infection of bovine epidermal cells. by sequential subcloning of high-bpv derivatives of id13, we isolated stable cell line ... | 1995 | 7491777 |
| suppression of cellular proliferation by the papillomavirus e2 protein. | carcinogenic progression of a human papillomavirus (hpv)-infected cell is often associated with integration of the viral genome in a manner which results in the loss of expression of the viral regulatory protein e2. one function of e2 is the regulation of expression of the viral oncogenes, e6 and e7. introduction of the bovine papillomavirus type 1 (bpv-1) e2 transactivator (e2-ta) in hela cells, an hpv type 18 (hpv-18)-positive cervical carcinoma cell line results in growth arrest. in this stud ... | 1995 | 7494290 |
| 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 |
| disparate replication properties of integrated and extrachromosomal forms of bovine papilloma virus in id13 cells. | bovine papillomavirus (bpv) previously has been reported to exist in transformed rodent cell lines as both chromosomally integrated and extrachromosomal forms. in the bpv-transformed mouse cell line id13, extrachromosomal bpv molecules replicate throughout s phase of the cell cycle in a random choice mode. we report here that these replication properties were altered for chromosomally integrated bpv dna in five independent id13 subclones. in all of the subclones, the integrated bpv sequences, wh ... | 1995 | 7490737 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| antibodies against linear and conformational epitopes of human papillomavirus type 16 that independently associate with incident cervical cancer. | in a seroepidemiological study of incident cervical cancer, 94 cases and 188 population-based controls were used to evaluate the disease-association of igg and iga antibody responses against 6 human papillomavirus (hpv) type-16 antigens. nine of the tested antibody responses were positively associated with cervical cancer, with odds ratios (ors) ranging from 2.5 to 15.0. the antibody responses most strongly associated with cervical cancer were iga against e6:10, an epitope derived from the carbo ... | 1995 | 7530234 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| replication efficiency of bovine papillomavirus type 1 dna depends on cis-acting sequences distinct from the replication origin. | the viral elements required for the initiation of replication of bovine papillomavirus type 1 dna include the origin region and two trans-acting factors, the e1 and e2 proteins. we now report that the replication efficiency of a dna molecule which contains these three elements is modulated by other viral sequences. by measuring the extent of replication of deleted viral genomes in transfected mouse cells, we identified sequences required for maximal efficiency. addition of these sequences to a c ... | 1995 | 7494277 |
| 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 |
| 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 |
| 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 |
| bovine papillomavirus type 4 in australia. | 1995 | 8534233 | |
| [bovine papillomavirus vector]. | 1995 | 8584697 | |
| early phase in the infection of cultured cells with papillomavirus virions. | the fate of full bovine papillomavirus (bpv) virions and virus-like particles after binding to c127 or cv-1 cells was studied by electron microscopy and indirect immunofluorescence. after incubation at 4 degrees for 1 hr, bpv virions were found to be bound to the plasma membrane, and most viruses were absorbed by the cells after 30 min incubation at 37 degrees. ninety minutes after the virions had been bound to the plasma membrane, the uptake of the virions was completed and most of the antigen ... | 1995 | 8525612 |
| co-operative interaction between the initiator e1 and the transcriptional activator e2 is required for replicator specific dna replication of bovine papillomavirus in vivo and in vitro. | the e1 polypeptide from bovine papillomavirus binds to the origin of replication (ori) and possesses the activities attributed to initiator proteins. e1 is also the only viral protein required for replication in a cell-free replication system. replication in vivo, however, absolutely requires in addition the viral transcription factor e2. we demonstrate that the basis for this distinction between in vitro and in vivo requirements is the limited sequence specificity of the e1 protein. e1 and e2, ... | 1995 | 8557041 |
| bpv e1 protein alters the kinetics of cell cycle entry of serum starved mouse fibroblasts. | a stable bovine papillomavirus e1 expressing cell line (c2e1) was used to investigate the effects of e1 protein on the requirement for growth factors during serum-induced reentry from quiescence to proliferation. flow cytometric bivariate dna/pcna analysis was utilized to study the expression of proliferating cell nuclear antigen (pcna) concomitant with this transition. c2e1 cells, unlike the control cells (cneo), were able to reenter the cell cycle when stimulated with low serum (1%). stimulati ... | 1995 | 8582248 |
| transgenic models for papillomavirus-associated multistep carcinogenesis. | to investigate the physiological and pathological in vivo functions of molecularly cloned genes, the transgenic mouse is one of the most useful experimental animal systems. many kinds of transgenic mice carrying papillomavirus genes have been produced, and the studies have revealed several new aspects in the field of papillomaviral oncology. among these transgenic mice, the mechanism of skin carcinogenis in the bovine papillomavirus (bpv) transgenic mouse has been well characterized, demonstrati ... | 1995 | 8682614 |
| [specific serologic studies with a novel authentic hpv antigen (virus-like particles) for hpv-6 antibodies in gynecologic patient samples]. | a serological assay for genital hpv infection would provide important additional information to hpv dna diagnostic methods, since it would evaluate prior exposure to the viruses, detect significant systemic immunologic response to virus infection, and could be performed in most clinical laboratories. | 1995 | 8672922 |
| the atp-binding and atpase activities of human papillomavirus type 16 e1 are significantly weakened by the absence of prolines in its atp-binding domain. | the e1 protein of human papillomavirus (hpv) type 16 is the only known papillomavirus e1 which does not contain any proline residues in the phosphate-loop (p-loop) of its atp-binding site. to ascertain whether this feature influences the activities of hpv-16 e1, we generated a mutant hpv-16 e1 (e1pro) in which prolines are inserted in place of alanines in this site, making the p-loop identical to its bovine papillomavirus type 1 counterpart. glutathione s-transferase (gst) fusion proteins (gste1 ... | 1995 | 8847499 |
| mutations in the human papillomavirus type 16 e2 protein identify a region of the protein involved in binding to e1 protein. | papillomavirus dna replication is primarily dependent upon two viral gene products, e1 and e2. work with bovine papillomavirus has shown that the e2 protein can bind directly to the e1 protein and enhance the binding of e1 to the viral origin of replication. however, little is known about the mechanism of interaction between e1 and e2 proteins. in this study we have analysed in detail the association between human papillomavirus type 16 (hpv-16) e1 and e2 proteins. using a purified glutathione s ... | 1995 | 9049327 |
| a high capacity assay for inhibitors of human papillomavirus dna replication. | the discovery of antiviral compounds against human papillomaviruses (hpv) has been hindered by the difficulties in culturing virus in vitro or assaying stable hpv dna replication. however, plasmids containing the hpv replication origin replicate transiently upon co-transfection with hpv e1 and e2 expression vectors. we have adapted this assay using secreted alkaline phosphatase (sap) as a reporter for rapid analysis of dna copy number. use of the sv40 early promoter in controlling sap expression ... | 1995 | 9636294 |
| status and transcriptional activity of a bovine-papillomavirus-i-based expression vector in a recombinant production cell line. | we have analysed the status and transcriptional activity of the bovine papillomavirus-i (complete bpv-i genome)-based expression vector pces in ci27i-cell-line-derived 3ti cells used for the industrial production of recombinant human erythropoietin (rhuepo). complete tandem head-to-tail integration of about 600 vector copies at a single site of the cellular genome was observed. deletions, insertions or rearrangements of pces-specific sequences or extrachromosomal copies of vector sequences were ... | 1996 | 8867900 |
| different arrangement of human papillomavirus e2 binding sites distinguishes cutaneous types from those associated with mucosal lesions. | high-risk-type human papillomavirus dna sequences are found in a high percentage of carcinomas from the uterine-cervix, with the viral e1-e2 gene region usually disrupted and the e6 and e7 oncoproteins consistently expressed. the e2 protein is known to repress early transcription from genital hpv promoters having a proximal e2 binding site (e2bs) close to the tata box. on the contrary, the e2 protein activates cutaneous early promoters having a longer distance between these sites. using an in vi ... | 1996 | 8854400 |
| e2 proteins: modulators of papillomavirus transcription and replication. | 1996 | 8902804 | |
| bovine papillomavirus oncoprotein e5 induces the nf kappa b activation through superoxide radicals. | bovine papillomavirus type 1 (bpv-1) open reading frame e5 encodes the smallest known oncoprotein. this protein is involved in transforming cells during the early stage of infection. nuclear factor kappa b (nf kappa b) is activated in the host cells as a result of different virus infections. it has been shown that reactive oxygen intermediates activate nf kappa b which leads the activation of several cellular genes. we studied the effect of bpv-1 es protein on nf kappa b activation. we found tha ... | 1996 | 8950027 |
| phenotypical characterization of lymphocytes infiltrating regressing papillomas. | papillomavirus-induced lesions often regress spontaneously in both humans and animals. papilloma regression is deemed to be due to a cell-mediated immune response, the nature of which is still ill defined, and is accompanied by immune cell infiltrates. to gain further information on the nature and role of the immune cells present in regressing papillomas, we have analyzed biopsies of papillomas induced in the soft palate of cattle by bovine papillomavirus type 4 (bpv-4) and have phenotypically c ... | 1996 | 8970967 |
| the bovine papillomavirus type 4 e8 protein binds to ductin and causes loss of gap junctional intercellular communication in primary fibroblasts. | the e8 open reading frame of bovine papillomavirus type 4 encodes a small hydrophobic polypeptide which contributes to cell transformation by conferring anchorage-independent growth. using an in vitro translation system, we show that the e8 polypeptide binds to ductin, the 16-kda proteolipid that forms transmembrane channels in both gap junctions and vacuolar h+-atpase. this association is not due to nonspecific hydrophobic interactions. ppa1, a saccharomyces cerevisiae polypeptide homologous (w ... | 1996 | 8971040 |
| the e5 gene product of rhesus papillomavirus is an activator of endogenous ras and phosphatidylinositol-3'-kinase in nih 3t3 cells. | we examined the effect of two rhesus papillomavirus 1 (rhpv) oncogenes on cytokine-induced signal transduction pathways leading to the possible activation of ras protein (p21ras) and phosphatidylinositol kinase. p21ras in both the activated (gtp-bound) and inactivated (gdp-bound) states were quantitated. nih 3t3 cell lines expressing the rhpv 1 e5 gene or epidermal growth factor receptor cdna had about a sixfold higher ratio of p21ras-bound gtp to p21ras-bound gdp as compared with parental nih 3 ... | 1996 | 8917513 |
| the initiator protein e1 binds to the bovine papillomavirus origin of replication as a trimeric ring-like structure. | the replication initiator protein e1 binds to the origin of replication of bovine papillomavirus in several forms. e1 can bind to its recognition sequence as a monomer together with the viral transcription factor e2, or as a trimeric e1 complex. the trimerization of e1 is mediated by the sequence-specific binding of e1 to dna, and results in an e1 complex that is linked topologically to the dna because the three molecules of e1 form a ring-like structure that encircles the dna. these results dem ... | 1996 | 8890182 |
| enhanced transcriptional activation by e2 proteins from the oncogenic human papillomaviruses. | a systematic comparison of transcriptional activation by papillomavirus e2 proteins revealed that the e2 proteins from high-risk human papillomaviruses (human papillomavirus type 16 [hpv-16] and hpv-18) are much more active than are the e2 proteins from low-risk hpvs (hpv-6b and hpv-11). despite the tropism of hpvs for particular epithelial cell types, this difference in transcriptional activation was observed in a number of different epithelial and nonepithelial cells. the enhanced activities o ... | 1996 | 8892874 |
| genetic analysis of the activation domain of bovine papillomavirus protein e2: its role in transcription and replication. | the bovine papillomavirus protein e2 serves dual functions in viral transcription and in the initiation of viral replication. as a transcription factor, e2 can cooperatively interact with cellular proteins such as sp1 and stimulate transcription of distal promoters. in replication, e2 and the helicase el are the only viral proteins required for accurate replication of templates containing the viral origin. the amino terminus of e2 is a functionally separable domain critical for activation of bot ... | 1996 | 8676438 |
| mapping of hpv-11 e1 binding site and determination of other important cis elements for replication of the origin. | the viral proteins e1 and e2 are essential for the replication of the hpv-11 origin. we have now mapped the e1 binding site (e1bs) and show by mutation analysis that the e1bs and an adjoining poly(a)-rich region are necessary for efficient replication of the origin. we have also shown, using suboptimal levels of e1 protein, that enhancement of e1 binding by e2 partially protects the e1bs. finally, we show that e1 can enhance the binding of e2 even in the absence of the e1bs. | 1996 | 8614991 |
| amino acids critical for the functions of the bovine papillomavirus type 1 e2 transactivator. | the n-terminal domain of the bovine papillomavirus type 1 e2 protein is important for viral dna replication, for transcriptional transactivation, and for interaction with the e1 protein. to determine which residues of this 200-amino-acid domain are important for these activities, single conservative amino acid substitutions have been generated in 17 residues that are invariant among all papillomavirus e2 proteins. the resulting mutated e2 proteins were tested for the ability to support viral dna ... | 1996 | 8523530 |
| transcriptional and replicational activation functions in the bovine papillomavirus type 1 e2 protein are encoded by different structural determinants. | a set of e2 proteins with mutations in the amino-terminal transactivation domain was made by a scheme called clustered charged-to-alanine scan. these mutant e2 proteins were tested for expression, stability, and compartmentalization in cells and for sequence-specific dna binding, as well as in functional assays for transcriptional and replicational activation. we identified four groups of mutants. first, mutants k111a, k112a, and e176a were unable to activate replication and transcription becaus ... | 1996 | 8709243 |
| simple procedure for creation of in-frame deletion mutations throughout an open reading frame. | a general method is presented for randomly mutagenizing open reading frames (orf) to generate in-frame deletions and insertions. the protocol requires expression of the orf of interest as a hybrid orf-beta-galactosidase fusion protein. this allows colorimetric screening for beta-galactosidase activity during subsequent mutagenesis steps. consequently, proteins with no suitable phenotypic selection or screening properties can be readily screened for mutations that disrupt and subsequently restore ... | 1996 | 8679203 |
| vaccination of cattle with bovine papillomavirus type 4 l2 elicits the production of virus-neutralizing antibodies. | prophylactic vaccination of cattle with the n terminus (l2a, aa 11-200) of the minor capsid protein l2 completely prevented bovine papillomavirus type 4 (bpv-4) infection of the alimentary canal. to investigate the mechanisms underlying protection from viral infection, sera from vaccinated animals were analysed in neutralization assays both in the nude mouse xenograft system and in cattle. bpv-4 retained its infectivity when incubated with preimmune cattle sera, whereas, when incubated with immu ... | 1996 | 8758002 |
| selection of the bovine papillomavirus type 1 nucleotide 3225 3' splice site is regulated through an exonic splicing enhancer and its juxtaposed exonic splicing suppressor. | alternative splicing is an important mechanism for the regulation of bovine papillomavirus type 1 (bpv-1) gene expression during the virus life cycle. however, one 3' splice site, located at nucleotide (nt) 3225, is used for the processing of most bpv-1 pre-mrnas in bpv-1-transformed c127 cells and at early to intermediate times in productively infected warts. at late stages of the viral life cycle, an alternative 3' splice site at nt 3605 is used for the processing of the late pre-mrna. in this ... | 1996 | 8676495 |
| in vitro generation and type-specific neutralization of a human papillomavirus type 16 virion pseudotype. | we report a system for generating infectious papillomaviruses in vitro that facilitates the analysis of papillomavirus assembly, infectivity, and serologic relatedness. cultured hamster bphe-1 cells harboring autonomously replicating bovine papillomavirus type 1 (bpv1) genomes were infected with recombinant semliki forest viruses that express the structural proteins of bpv1. when plated on c127 cells, extracts from cells expressing l1 and l2 together induced numerous transformed foci that could ... | 1996 | 8709207 |
| characterization of the single-strand-specific bpv-1 origin binding protein, spsf i, as the hela pur alpha factor. | spsf i and ii are two cellular proteins which bind specifically to single-stranded dna. spsf i and ii binding sites are found in the minimal origin of replication of bpv-1 dna and near the p2 promoter of the cellular c-myc gene. dna-binding properties of the two proteins to single-stranded oligonucleotides of different lengths and sequences were quantified by determination of dna-binding constants. the binding constant of spsf proteins to the lower strand of the bpv-1 origin was determined to be ... | 1996 | 8759014 |
| surface conformational and linear epitopes on hpv-16 and hpv-18 l1 virus-like particles as defined by monoclonal antibodies. | a panel of 24 monoclonal antibodies (mabs) was generated against human papillomavirus (hpv) types 16 and 18 l1 virus-like particles (vlps). the mabs were screened for reactivity to a variety of vlps prepared from hpv-6, -11, -16, -18, -31, -33, -35, and -45, cottontail rabbit papillomavirus, bovine papillomavirus type 1, and a set of 35 overlapping 20-amino-acid peptides spanning the entire hpv-16 l1 gene. type-specific linear and conformational surface epitopes were detected as well as several ... | 1996 | 8806551 |
| bovine papillomavirus type 4 dna isolated from a skin lesion in a steer. | a lesion on the head of a steer, defined histologically as an epithelial papilloma, yielded dna which did not hybridise with any of the bovine papillomavirus dnas usually associated with the formation of skin lesions. dna from the lesion did hybridise with dna from bovine papillomavirus 4, even under stringent conditions, and contained a sequence that could be amplified by polymerase chain reaction with primers specific for that virus. bovine papillomavirus 4 had previously been isolated only fr ... | 1996 | 8733180 |
| carboxyl terminus of bovine papillomavirus type-1 l1 protein is not required for capsid formation. | the papillomavirus major capsid protein l1 can assemble into capsids in vitro. to identify areas within the bovine papillomavirus type-1 l1 (bpv l1) protein that are important for virus assembly, we constructed a set of 24 baculovirus recombinants expressing bpv l1 deletion mutants that span the entire l1 open reading frame. virus-like particle (vlp) formation of the l1 mutants was examined by electron microscopy. wild-type (wt) bpv l1 expressed in recombinant baculovirus formed vlps, while caps ... | 1996 | 8806558 |
| serologic association between human papillomavirus type 16 infection and esophageal cancer in shaanxi province, china. | the existence of large geographic variations in the prevalence of esophageal cancer in some countries, such as china, indicates that environmental risk factors may be important in the development of this disease. some studies have implicated genital-mucosal strains of human papillomaviruses (hpvs) in the etiology of this cancer. | 1996 | 8841021 |
| cis and trans requirements for stable episomal maintenance of the bpv-1 replicator. | papillomavirus genomes are maintained as multicopy nuclear plasmids in transformed cells. to address the mechanisms by which the viral dna is stably propagated in the transformed cells, we have constructed a cell line ch04.15 expressing constitutively the viral proteins e1 and e2, that are required for initiation of viral dna replication. we show that these viral proteins are necessary and sufficient for stable extrachromosomal replication. using the cell line ch04.15, we have shown that the bov ... | 1996 | 8598191 |
| e5 oncoprotein transmembrane mutants dissociate fibroblast transforming activity from 16-kilodalton protein binding and platelet-derived growth factor receptor binding and phosphorylation. | the e5 oncoprotein of bovine papillomavirus type 1 is a 44-amino-acid, hydrophobic polypeptide which localizes predominantly in golgi membranes and appears to transform cells through the activation of tyrosine kinase growth factor receptors. in fibroblasts, e5 interacts with both the 16-kilodalton vacuolar atpase subunit and the platelet-derived growth factor receptor (pdgf-r) via its hydrophobic transmembrane domain and induces autophosphorylation of the receptor. to further analyze the correla ... | 1996 | 8642670 |
| the bovine papillomavirus type 1 e2 transactivator and repressor proteins use different nuclear localization signals. | the e2 gene of bovine papillomavirus type 1 encodes at least three nuclear phosphoproteins that regulate viral transcription and dna replication. all three proteins have a common c-terminal domain that has dna-binding and dimerization activities. a basic region in this domain forms an alpha helix which makes direct contact with the dna target. in this study, it is shown that in addition to its role in dna binding, this basic region functions as a nuclear localization signal both in the e2 dna-bi ... | 1996 | 8551571 |
| the bpv-1 e2 dna-contact helix cysteine is required for transcriptional activation but not replication in mammalian cells. | the papillomavirus e2 protein contains an amino-terminal region thought necessary and sufficient to support transcriptional activation and a carboxy-terminal region shown to direct sequence-specific dna binding and dimerization. a cysteine residue in the center of the e2 dna recognition helix is highly conserved among papillomavirus e2 proteins. mutations of this cysteine in bovine papillomavirus type 1 e2 to serine and glycine resulted in proteins which failed to activate e2-dependent promoters ... | 1996 | 8599215 |
| stable expression of the reovirus mu2 protein in mouse l cells complements the growth of a reovirus ts mutant with a defect in its m1 gene. | reovirus mu2 protein was constitutively expressed in mammalian cells transfected with dicistronic constructs in which the reovirus m1 gene and the selectable neomycin-resistant gene (neo) were both driven by the same phosphoglycerate kinase promoter. translation of neo was initiated with the cap-independent translation initiation element from encephalomyocarditis virus. expression of mu2 protein was detected by mu2-specific antibody produced through immunization of rabbits with trp-e-mu2 fusion ... | 1996 | 8599234 |
| transcriptional activation function is not required for stimulation of dna replication by bovine papillomavirus type 1 e2. | bovine papillomavirus type 1 replication was previously shown to require both the e1 initiator protein and the e2 transactivator protein. we show here that e1, in the absence of e2, is sufficient for low-level bovine papillomavirus type 1 dna replication in c-33a cells. in addition, studies of genetically isolated e2 point mutants demonstrate that enhancement of replication by e2 does not require its transcriptional activation function. the uncoupling of the e2 functions suggests that stimulatio ... | 1996 | 8794380 |
| pituitary-specific chromatin structure of the rat prolactin distal enhancer element. | the location of target dna sequences within chromatin may affect the ability of trans-acting factors to bind cis-elements and regulate gene transcription. to examine the effect of chromatin structure on the ability of the estrogen-estrogen receptor complex (e2r) to bind its respective dna binding element within the rat prolactin (rprl) gene and modulate rprl gene expression, we have developed cell lines derived from the rprl-expressing (rprl+) rat pituitary cell line gh3 and the rprl-non- expres ... | 1996 | 8604340 |