| papillomavirus associated skin lesions in a cat seropositive for feline immunodeficiency virus. | a cat was presented with skin lesions consisting of slightly raised pigmented plaques, 2-7 mm in diameter with a rough slightly verrucous surface. histologically these lesions were identified as papillomas. a papillomavirus infection was demonstrated: virus-like particles were present in the nuclei of cells within the lesions, and staining with an anti-bovine papillomavirus (bpv-1) antibody was obtained. an infection with feline immunodeficiency virus was diagnosed in this cat; this condition ha ... | 1992 | 1320786 |
| mammalian and viral dna sequences which interfere with the maintenance of a centromeric vector in yeast. | we constructed a recombinant plasmid by inserting into the prs314 yeast centromeric plasmid vector the mouse dna sequence responsible for the maintenance in transgenic mice of plasmid p12b1 (1). such constructs could constitute convenient shuttle vectors between yeast and mouse cells. however, the recombinant molecule could not be established as a stable plasmid in saccharomyces cerevisiae. a region with a limited similarity to the yeast centromere (cen element) is present in this mouse sequence ... | 1992 | 1326955 |
| evidence that the transcriptional trans-activating function of the bovine papillomavirus type 1 e2 gene is not required for viral dna amplification in division-arrested cells. | amplification of bovine papillomavirus type 1 (bpv-1) dna in growth-arrested mouse cell cultures appears to mimic the process of induction of vegetative bpv-1 dna synthesis in cells of the stratum spinosum in productively infected bovine warts. in both cases, cells permissive for viral dna amplification express large amounts of viral e2 protein which accumulates within the cell nucleus. whereas in latently infected virus-transformed cells truncated transcriptional repressor forms of e2 predomina ... | 1992 | 1328476 |
| the e2 binding sites determine the efficiency of replication for the origin of human papillomavirus type 18. | human papillomaviruses (hpv-s) have been shown to possess transforming and immortalizing activity for many different, mainly keratinocyte cell lines and they have been detected in 90% of anogenital cancer tissues, which suggests a causative role in the induction of anogenital and other tumours. we have exploited a quantitative assay to identify and characterize the origin of replication of the human papillomavirus type 18 (hpv-18), one of the most prevalent types in the high-risk hpv group. repl ... | 1992 | 1334259 |
| the bpv-1 e5 oncoprotein expressed in schizosaccharomyces pombe exhibits normal biochemical properties and binds to the endogenous 16-kda component of the vacuolar proton-atpase. | the 44-amino-acid e5 oncoprotein of bovine papillomavirus type 1 transforms immortalized murine fibroblast cell lines. this highly hydrophobic protein forms homodimers, localizes to intracellular membrane compartments (including the golgi apparatus), and forms a complex with the 16-kda membrane-embedded constituent (16k) of the vacuolar proton-atpase. to develop a system for the genetic and biochemical analysis of the e5/16k interaction, the e5 gene was cloned into a new vector which was designe ... | 1992 | 1387753 |
| genital bovine papillomavirus infection in saudi arabia. | genital bovine papillomavirus infection was observed for the first time in the al-ahsa region of saudi arabia. the disease involved 1 female and 2 male 2-4-year-old crossbred cattle. fibropapillomas (warts) were limited to the prepuce and vulva. electron micrographs of thin sections of the lesions revealed the presence of intranuclear viruslike particles. using a broadly cross-reactive rabbit polyclonal antiserum directed against papillomavirus group-specific antigens, the infection was confirme ... | 1991 | 1645597 |
| bovine papillomavirus type 1 alters the processing of host glucose- and calcium-modulated endoplasmic reticulum proteins. | we have previously characterized five proteins induced by the presence of the e2 open reading frame (orf) region of bovine papillomavirus type 1 (bpv-1) in c127 mouse fibroblasts (r. m. levenson, u. g. brinckmann, m. k. o'banion, e. j. androphy, j. t. schiller, f. tabatabai, l. p. turek, k. neary, m. t. chin, t. r. broker, l. t. chow, and d. a. young, virology 172:170-179, 1989). by specific immunoprecipitation, we now find that one of the papillomavirus-associated proteins (pvp1) is a highly gl ... | 1991 | 1645780 |
| a glutamine residue in the membrane-associating domain of the bovine papillomavirus type 1 e5 oncoprotein mediates its binding to a transmembrane component of the vacuolar h(+)-atpase. | the 44-amino-acid e5 oncoprotein is the major transforming protein of bovine papillomavirus type 1. it is a highly hydrophobic polypeptide which dimerizes and localizes to the golgi apparatus and endoplasmic reticulum membranes. recent evidence suggests that e5 modulates the phosphorylation and internalization of the epidermal growth factor and colony-stimulating factor 1 receptors and constitutively activates platelet-derived growth factor receptors in c127 and fr3t3 cells. although no direct i ... | 1992 | 1370089 |
| papillomavirus l1 major capsid protein self-assembles into virus-like particles that are highly immunogenic. | infection by certain human papillomavirus types is regarded as the major risk factor in the development of cervical cancer, one of the most common cancers of women worldwide. analysis of the immunogenic and structural features of papillomavirus virions has been hampered by the inability to efficiently propagate the viruses in cultured cells. for instance, it has not been established whether the major capsid protein l1 alone is sufficient for virus particle assembly. in addition, it is not known ... | 1992 | 1334560 |
| the bpv-1 e5 protein, the 16 kda membrane pore-forming protein and the pdgf receptor exist in a complex that is dependent on hydrophobic transmembrane interactions. | the e5 oncoprotein of bovine papillomavirus type 1 is a 44 amino acid, highly hydrophobic protein that induces the stable transformation of immortalized murine fibroblasts, presumably through its activation of growth factor receptors. previous studies have shown that the e5 protein complexes with the 16 kda (16k) pore-forming protein of vacuolar h(+)-atpases. this integral membrane protein is essential for the acidification and function of subcellular compartments that process growth factor rece ... | 1992 | 1334459 |
| properties of bovine papillomavirus e1 mutants. | ostensibly comparable mutants of bovine papillomavirus type 1 (bpv-1) affecting the e1 open reading frame that were constructed in several laboratories have been reported to exhibit either reduced or increased transformation efficiencies in established mouse cell lines relative to wild-type bpv-1 dna. to resolve these discrepancies, we have reexamined many of the mutants in mouse c127 cells by using focus formation assays. our primary conclusions are that all e1 mutants tested consistently gener ... | 1992 | 1333131 |
| rolling-circle replication of a high-copy bpv-1 plasmid. | we investigated the replicating form of a bovine papillomavirus type 1 (bpv-1) deletion mutant by direct electron-microscopic analysis of low molecular weight cellular dna fractions. the detection of viral plasmid dna replication intermediates was facilitated by the isolation of a spontaneously transformed mouse cell subclone containing an unusually high viral genome copy number (approx. 1000 per cell), and by employing a slight modification of the hirt fractionation procedure to reduce the leve ... | 1992 | 1333015 |
| immunofluorescent detection of bovine papillomavirus e4 antigen in the cytoplasm of cells permissive in vitro for viral dna amplification. | the e4 gene of several human papillomavirus types is expressed in association with vegetative viral dna synthesis in differentiated epidermal cells. to develop reagents to study expression of the bovine papillomavirus type 1 (bpv-1) e4 gene in warts and in virus-transformed cell lines, rabbit polyclonal antiserum was raised to the bpv-1 e4 antigen produced as a fusion polypeptide in escherichia coli. by immunoblotting analysis of productively infected bovine fibropapilloma tissue, e4-related pro ... | 1991 | 1654378 |
| the induction of il-6 and gelatinase b by il-1 in mouse cell lines transformed with bovine papillomavirus: decreased production in tumorigenic cells. | six cell lines, that were cloned from murine c127 cells infected by bovine papillomavirus type 1 (bpv1), were found to differ in the degree of transformation in vitro and of tumorigenicity in vivo. in these cell lines the degree of tumorigenicity was inversely correlated with il-6 induction by il-1 beta. whereas the parental c127 cell line produced 15-30 u/ml of il-6 spontaneously, none of the transformed cell lines produced significant levels of il-6 constitutively. on induction by human il-1 b ... | 1992 | 1330001 |
| the spermicide nonoxynol-9 does not inactivate papillomavirus. | vaginal spermicides are effective contraceptive, and are also capable of inactivating many sexually transmitted pathogens by their detergent effect on bacterial cell membranes and viral envelopes. a 5% concentration of nonoxynol-9, the most frequently used active ingredient of spermicides, was tested for its ability to reduce the transforming activity of bovine papillomavirus type 1 (bpv-1), and the infectivity of bk virus (bkv) and cytomegalovirus (cmv). nonoxynol-9 markedly reduced the infecti ... | 1992 | 1329236 |
| replication of bovine papillomavirus vectors in murine cells. | varying capacities for autonomous replication have been obtained with bovine papillomavirus type 1 (bpv-1)-based expression vectors in mouse c127 cells. both integration of the vector dna into the genome of the host cell and replication as monomeric extrachromosomal elements have been observed. in this study, we have examined what features of bpv-1 vectors influence their replication potential. transfection of the entire bpv-1 genome into c127 cells resulted in the replication of extrachromosoma ... | 1992 | 1327973 |
| molecular cloning, analysis, and chromosomal localization of a mouse genomic sequence related to the human papillomavirus type 18 e5 region. | the e5 open reading frame (orf) from bovine papillomavirus type 1 (bpv 1) as well as the e5 orfs from human papillomaviruses (hpv) type 6 and type 16 have been reported to transform immortalized rodent cells. in an analysis of murine and human tumors for the presence of putative papillomavirus-related sequences, we cloned amplified cellular sequences from the mouse cell line eb that cross-hybridized with the e5 orf of hpv 18. a 2.1-kb fragment termed hc1 was sequenced. in normal murine cells, it ... | 1992 | 1326990 |
| two cellular single-strand-specific dna-binding proteins interact with two regions of the bovine papillomavirus type 1 genome, including the origin of dna replication. | we have identified and purified to near homogeneity two specific single-stranded dna-binding factors (spsf i and ii) with molecular masses of 42 and 39 kda, respectively, from calf thymus. gel retention analysis and competition experiments demonstrate that the ubiquitous proteins spsf i and ii specifically interact with single-stranded dna derived from the minimal in vitro origin of replication of bovine papillomavirus type 1 and a region of the viral genome proposed to be involved in plasmid ma ... | 1992 | 1326653 |
| transient replication of human papillomavirus dnas. | information on papillomavirus dna replication has primarily derived from studies with bovine papillomavirus type 1 (bpv-1). our knowledge of dna replication of the human papillomaviruses (hpvs) is quite limited, in part because of the lack of a cell culture system capable of supporting the stable replication of hpv dna. this study demonstrates that the full-length genomic dnas of hpv types 11 and 18 (hpv-11 and hpv-18), but not hpv-16, are able to replicate transiently after transfection into se ... | 1992 | 1326651 |
| conserved cysteine residue in the dna-binding domain of the bovine papillomavirus type 1 e2 protein confers redox regulation of the dna-binding activity in vitro. | the bovine papillomavirus type 1 e2 open reading frame encodes three proteins involved in viral dna replication and transcriptional regulation. these polypeptides share a carboxyl-terminal domain with a specific dna-binding activity; through this domain the e2 polypeptides form dimers. in this study, we demonstrate the inhibition of e2 dna binding in vitro by reagents that oxidize or otherwise chemically modify the free sulfhydryl groups of reactive cysteine residues. however, these reagents had ... | 1992 | 1323841 |
| the e5 oncoprotein of bovine papillomavirus binds to a 16 kd cellular protein. | the e5 oncoprotein of bovine papillomavirus type 1 is the smallest known viral transforming protein. it is a 44 amino acid polypeptide asymmetrically oriented in golgi and plasma membranes which appears to modify (either directly or indirectly) the internalization and phosphorylation of at least two growth factor receptors: egf and csf-1. to identify cellular proteins associated with e5, we have constructed two e5 fusion proteins, each of which contains a well-characterized epitope at the e5 ami ... | 1990 | 1688529 |
| transcription of bpv-1 genes in transfected f9 cells. | in f9 cells transformed with bovine papillomavirus type 1 (bpv-1) sequences two different phenotypes can be recognized. one cell type shows the characteristics of the parental stem cell line, whereas the other comprises cells with spindle-like morphology that do not adhere to each other, similar to retinoic acid-treated f9 embryonal carcinoma cells. the phenotypically altered cells plate more efficiently than the stem cells, grow well in soft agar and show an extended lifespan in the differentia ... | 1992 | 1323821 |
| control of human papillomavirus type 11 origin of replication by the e2 family of transcription regulatory proteins. | replication of human papillomavirus type 11 (hpv-11) dna requires the full-length viral e1 and e2 proteins (c.-m. chiang, m. ustav, a. stenlund, t. f. ho, t. r. broker, and l. t. chow, proc. natl. acad. sci. usa 89:5799-5803, 1992). using transient transfection of subgenomic hpv dna into hamster cho and human 293 cells, we have localized an origin of replication (ori) to an 80-bp segment in the upstream regulatory region spanning nucleotide 1. it overlaps the e6 promoter region and contains a sh ... | 1992 | 1323690 |
| effect of interferon gamma on the sensitivity of bovine-papilloma-virus(bpv1)-transformed cell lines to cell-mediated cytotoxicity. | the effect of interferon gamma (ifn gamma) on the immunogenicity and immunosensitivity of mouse cell lines transformed by bovine papillomavirus type 1 (bpv1) dna was examined in a syngeneic mouse model. the overnight incubation of bpv1-transformed cell lines with 100 iu/ml ifn gamma did not affect their ability to induce the generation of cytotoxic effector cells but it clearly increased their sensitivity to lysis by interleukin-2-induced lymphokine-activated killer (lak) cells and by non-specif ... | 1992 | 1322243 |
| viral e1 and e2 proteins support replication of homologous and heterologous papillomaviral origins. | we have shown that e1 and e2 proteins of human papillomavirus type 11 (hpv-11) were essential to support the replication of the homologous viral origin (ori) in a transient replication assay, similar to reports on bovine papillomavirus type 1 (bpv-1). unexpectedly, matched or even mixed combinations of e1 and e2 proteins from hpv-11 or bpv-1 replicated either ori in human, monkey, and rodent cell lines of epithelial or fibroblastic lineage, albeit with varied efficiencies. either set of viral pr ... | 1992 | 1321423 |
| identification and genetic definition of a bovine papillomavirus type 1 e7 protein and absence of a low-copy-number phenotype exhibited by e5, e6, or e7 viral mutants. | the bovine papillomavirus type 1 (bpv-1) genome replicates as a multiple-copy plasmid in murine c127 cells transformed to neoplasia by virus infection or by transfection with bpv-1 dna. it was reported previously that bpv-1 genomes harboring frameshift mutations in the e6 or e7 open reading frame (orf) replicated in c127 cells transformed by these mutants at a low copy number. furthermore, the characterization of a bpv-1 mrna in which the e6 and e7 orfs were spliced together in frame has led to ... | 1992 | 1321280 |
| localization of bovine papillomavirus type 1 e5 protein to transformed basal keratinocytes and permissive differentiated cells in fibropapilloma tissue. | we examined expression of the e5 transforming protein of bovine papillomavirus type 1 (bpv-1) in naturally and experimentally infected bovine cells. bovine conjunctival fibroblasts transformed in vitro by experimental infection with purified bpv-1 virions expressed significantly higher amounts of the 7-kda e5 protein than bpv-1-transformed murine c127 cells. indirect immunofluourescence analysis revealed a cytoplasmic, predominantly juxtanuclear, localization of e5 protein in the in vitro virus- ... | 1992 | 1319069 |
| bovine papillomavirus type 1-transformed primary mouse fibroblasts show no correlation between tumorigenicity and viral gene expression, but c-myc gene expression is elevated in tumorigenic cell lines. | bovine papillomavirus type 1 (bpv-1)-transformed primary mouse fibroblasts containing episomal or integrated bpv-1 sequences were analysed for virus-specific transcripts and c-myc gene expression. total bpv-1-specific expression was high in cell lines containing episomal bpv-1 dna in comparison to lines containing integrated bpv-1 sequences, mainly due to higher expression of the e6/e7 sequences. no correlation was found between the viral transcription and tumorigenicity, although bpv-1 gene exp ... | 1992 | 1318945 |
| early promoters of genital and cutaneous human papillomaviruses are differentially regulated by the bovine papillomavirus type 1 e2 gene product. | the physical state of the human papillomavirus (hpv) genome is usually different in malignant lesions of the skin, in which it is generally found in episomal form, and genital mucosa, in which it is frequently integrated with disruption of the e2 gene. using chimeric or natural hpv promoters in the presence of the bovine papillomavirus type 1 e2 gene product, we observed transcription activation or repression, depending on the distance of e2-binding motifs from the start site. we found a clear d ... | 1992 | 1318941 |
| inhibition of bovine papillomavirus plasmid dna replication by adeno-associated virus. | the helper-dependent human parvovirus adeno-associated virus type 2 (aav) inhibits both the oncogenic transforming abilities and the dna replication of its helper viruses, adenovirus (ad), and herpes simplex virus (hsv). as aav-2 also inhibits the transforming ability of bovine papillomavirus type 1 (bpv), aav-2 was assayed for its ability to inhibit bpv plasmid dna replication. here we find that the aav-2 rep78 gene is able to trans-inhibit bpv plasmid dna replication and that the aav-2 termina ... | 1992 | 1318608 |
| the bovine papillomavirus constitutive enhancer is essential for viral transformation, dna replication, and the maintenance of latency. | bovine papillomavirus type 1 (bpv-1) has served as the prototype papillomavirus for the study of viral transcription, dna replication, and latency. however, no cis essential transcription control regions which are necessary for both transformation and replication of bpv-1 or any other papillomavirus have yet been defined. we have found that bpv-1 mutants with deletions in the long control region were defective for transformation and replication, with the essential region in the 5' long control r ... | 1992 | 1312634 |
| human papillomavirus type 16 e5 gene stimulates the transforming activity of the epidermal growth factor receptor. | we have until recently made several unsuccessful attempts to assign any activity to the human papillomavirus type 16 (hpv-16) e5 gene product. however, studies with the bovine papilloma virus 1 (bpv-1) e5 protein indicated an interaction with the epidermal growth factor receptor (egfr). in light of the overall similarity between the hpv and bpv e5 proteins we attempted to determine whether the hpv-16 e5 gene had any common activity. in cells expressing high levels of egfr plus hpv-16 e5 we found ... | 1992 | 1311063 |
| integration of bovine papillomavirus type 1 dna and analysis of the amplified virus-cell junctions in transformed primary mouse fibroblasts. | we have analysed the site of bovine papillomavirus type 1 (bpv-1) dna integration in clones originating from a transformed primary mouse fibroblast cell line established by transfection of linear bpv-1 dna. viral dna was integrated at a single site in the host genome with an intact early region and an almost complete long control region. sequence analysis showed that the bpv-1 dna was integrated at the hindiii site (the enzyme used to linearize the bpv-1 dna for transfection) with short deletion ... | 1992 | 1309860 |
| topological properties of bovine papillomavirus type 1 (bpv-1) dna in episomal nucleoprotein complexes: a model system for chromatin organization in higher eukaryotes. | sedimentation analysis of isolated episomal bovine papillomavirus type 1 (bpv-1) nucleoprotein complexes in sucrose gradients and subsequent separation of the purified dna in chloroquine gels revealed different classes of molecules, varying in their degree of superhelicity. since torsionally stressed dna favors the adoption of secondary structures, we employed the single-strand-specific s1 nuclease to detect such structural alterations in both naked dna and native chromatin. direct examination o ... | 1991 | 1648363 |
| bovine papillomavirus e5 oncoprotein binds to the 16k component of vacuolar h(+)-atpases. | the major transforming protein of bovine papillomavirus type 1, e5, is mainly associated with endomembranes, specifically binding to a cellular protein of relative molecular mass 16,000 (16k). at the same time as transformation, e5 causes the phosphorylation of tyrosine residues in epidermal and platelet-derived growth factor receptors. we show here that the 16k protein associated with e5 is the 16k component of vacuolar atpases. this protein is known to be an integral membrane protein in endoso ... | 1991 | 1649407 |
| characterization of bpv-like dna in equine sarcoids. | the dna from equine sarcoid samples from new york state and switzerland was isolated and probed with bovine papillomavirus type 1 (bpv-1) to determine if bpv genomes were present. twelve of 13 sarcoids from new york state and 17/20 sarcoids from switzerland contained dna that hybridized to the bpv-1 probe. restriction enzyme analysis of the positive samples demonstrated restriction fragment profiles characteristic of bpv-1 in 22 sarcoids and restriction fragment profiles characteristic of bovine ... | 1991 | 1650553 |
| initiation of transcription from the minute virus of mice p4 promoter is stimulated in rat cells expressing a c-ha-ras oncogene. | transformation of fr3t3 rat fibroblasts by a c-ha-ras oncogene but not by bovine papillomavirus type 1 is associated with an increase in the abundance of mrnas from prototype strain mvmp of infecting minute virus of mice, an oncosuppressive parvovirus. this differential parvovirus gene expression correlates with the reported sensitization of ras- but not bovine papillomavirus type 1-transformed cells to the killing effect of mvmp (n. salomé, b. van hille, n. duponchel, g. meneguzzi, f. cuzin, j. ... | 1991 | 1651412 |
| biological properties of the deer papillomavirus e5 gene in mouse c127 cells: growth transformation, induction of dna synthesis, and activation of the platelet-derived growth factor receptor. | we determined the biological activities of the 44-amino-acid deer papillomavirus (dpv) e5 protein in mouse c127 cells. the dpv e5 gene can induce focus formation, stable and acute morphologic transformation, and dna synthesis, and it activates the platelet-derived growth factor (pdgf) beta receptor as assessed by increased constitutive tyrosine phosphorylation of mature and precursor receptor forms. thus, the dpv e5 protein has biological activities similar to those of the closely related e5 pro ... | 1991 | 1651413 |
| activation of bpv-1 replication in vitro by the transcription factor e2. | soluble extracts from uninfected murine cells supplemented with purified viral e1 and e2 proteins support the replication of exogenously added papilloma virus dna. the e2 transactivator stimulates the binding of the e1 replication protein to the minimal origin of replication and activates dna replication. these results support the concept that transcription factors have a direct role in the initiation of dna replication in eukaryotes by participating in the assembly of a complex at the origin of ... | 1991 | 1656277 |
| studies on vaccination against papillomaviruses: the immunity after infection and vaccination with bovine papillomaviruses of different types. | calves, free of antibodies to bovine papillomaviruses (bpv), were reared in isolation. one was infected with bpv-2, developed tumours and was resistant to homologous reinfection. groups of calves were infected with bpv-2, bpv-5 or bpv-6; they all developed and subsequently rejected type-specific tumours. they were then infected with bpv-4; they were not immune and oral papillomas were induced. groups of animals were vaccinated by intramuscular preparations of purified bpv-4 and bpv-6 and were ch ... | 1990 | 2161579 |
| vaccinia recombinants expressing early bovine papilloma virus (bpv1) proteins: retardation of bpv1 tumour development. | papillomaviruses are aetiological agents of epithelial proliferative diseases in animals and in man. it was previously demonstrated that animals inoculated with live vaccinia recombinants expressing early proteins of polyoma virus resist challenge with polyoma-tumour cells, and this approach has been extended to the development of a vaccine against papillomavirus-transformed cells. bovine papillomavirus type 1 (bpv1), a virus responsible for dermal lesions in cattle, is a prototype virus of the ... | 1990 | 2163573 |
| bovine papillomavirus with a mutation in the e2 serine 301 phosphorylation site replicates at a high copy number. | the e2 open reading frame of bovine papillomavirus type 1 (bpv-1) encodes at least three proteins with transcriptional regulatory properties. the full-length e2 open reading frame encodes a transcriptional transactivator, and the 3' region encodes two smaller polypeptides that repress e2-mediated transactivation. the full-length gene product is also required for viral dna replication. we have demonstrated that the bpv-1 e2 polypeptides are phosphorylated primarily on two serine residues at a sit ... | 1991 | 1658358 |
| tumorigenic transformation of murine keratinocytes by the e5 genes of bovine papillomavirus type 1 and human papillomavirus type 16. | to examine the biological properties of the bovine papillomavirus type 1 (bpv) and human papillomavirus type 16 (hpv16) e5 genes, each was cloned separately into a retroviral expression vector and helper-free recombinant viruses were generated in packaging cell lines. the bpv e5 retroviruses efficiently caused morphologic and tumorigenic transformation of cultured lines of murine fibroblasts, whereas the hpv16 e5 viruses were inactive in these assays. in contrast, infection of the p117 establish ... | 1991 | 1658398 |
| papillomavirus trans-activator protein e2 activates expression from the promoter for the ribonucleotide reductase large subunit from herpes simplex virus type 2. | activation of the herpes simplex virus type 2 (hsv-2) large subunit of the ribonucleotide reductase (icp10) gene by papillomavirus dna encoding the e2 or e7 proteins was studied directly by immunofluorescence or by chloramphenicol acetyltransferase (cat) analysis with hybrid icp10 or ie175 and 38k promoter constructions. cotransfection with bovine papillomavirus type 1 or human papillomavirus type 16 (hpv-16) e2 dna enhanced cat expression from constructions in which cat is regulated by the icp1 ... | 1990 | 2167936 |
| identification of a 68-kilodalton nuclear atp-binding phosphoprotein encoded by bovine papillomavirus type 1. | e1 is the largest open reading frame (orf) of bovine papillomavirus type 1 (bpv-1) and is highly conserved among all papillomaviruses, maintaining its size, amino acid composition, and location in the viral genome with respect to other early genes. multiple viral replication functions have been mapped to the e1 orf of bpv-1, and evidence suggested that more than one protein was encoded by this orf. we previously identified a small protein (m) whose gene consists of two exons, one encoded by the ... | 1990 | 2168988 |
| cell transformation induced by bovine papillomavirus dna as an assay for tumor promoters and chemopreventive agents. | an in vitro assay was designed to examine and quantitate the action of chemical promoters and chemopreventive agents on papillomavirus dna-carrying cells. cultured c3h/10t1/2 cells transfected with bovine papillomavirus type 1 dna (plasmid pdbpv-1) were used as targets, and the frequency of transformed foci was used as an endpoint. the development of foci with a transformed phenotype was greatly enhanced by tumor promoters (e.g., mezerein, 12-o-tetradecanoyl-phorbol-13-acetate, teleocidin, and o ... | 1991 | 1661204 |
| induction of bovine papillomavirus e2 gene expression and early region transcription by cell growth arrest: correlation with viral dna amplification and evidence for differential promoter induction. | the bovine papillomavirus type 1 (bpv-1) genome replicates as a latent plasmid in mouse c127 cells transformed in vitro by the virus. however, we have recently shown that bpv-1 dna amplification can be induced in a subpopulation of cells under culture conditions which suppress cell proliferation, a finding which led us to hypothesize that expression of a viral replication factor was regulated by cell growth stage. in this report, we describe the detection in these cells of abundant bpv-1 nuclear ... | 1990 | 2170685 |
| [recombinant murine cell lines transformed by various vectors based on bovine papillomavirus type 1 and expressing human tissue plasminogen activator]. | we have constructed a number of vectors which include transcriptional unit of human tpa cdna and 100% bpv-1 dna or 100% lx dna (mutant bpv variant with tandem duplication of lcr-e6-e7 region). additional hsv-1 tk-promoter was inserted in the flanks of viral dnaa in a set of constructions. a number of recombinant cell lines have been established by means of transformation using the constructed vectors. the increased focus formation activity and the improved vector properties were demonstrated for ... | 1991 | 1661373 |
| enhancer effect of bovine papillomavirus e2 protein in replication of polyomavirus dna. | in polyomavirus, both transcription from the early promoter and viral dna replication initiated at the origin of dna replication is controlled by binding of proteins to the enhancer region. we have developed a simple model system to study the role of an enhancer binding factor in the initiation of polyomavirus dna replication. a reporter plasmid was constructed which has the enhancer region replaced by two binding sites for a transcription factor, the e2 protein encoded by bovine papillomavirus ... | 1991 | 1662803 |
| structures of bovine and human papillomaviruses. analysis by cryoelectron microscopy and three-dimensional image reconstruction. | the structures of bovine papillomavirus type 1 (bpv-1) and human papillomavirus type 1 (hpv-1) were determined at 2.5 nm resolution by cryoelectron microscopy and three dimensional image reconstruction techniques. as expected, the reconstructions showed that both viruses consist of a t = 7 icosahedral capsid (approximately 60 nm in diameter) which surrounds a nucleohistone core. the capsid morphologies of the two viruses are nearly indistinguishable. each capsid consists of a shell layer (approx ... | 1991 | 1663794 |
| antibody-mediated neutralization in vivo of infectious papillomaviruses. | specific antibody-mediated neutralization of infectious human papillomavirus type 11 (hpv-11) was achieved in the athymic mouse xenograft system, in which hpv-11 induced morphological transformation of human foreskin. virus-specific neutralization was demonstrated by the ability of an hpv-11-specific polyclonal antiserum to neutralize hpv-11 infectivity and not bovine papillomavirus type 1 (bpv-1) or cottontail rabbit papillomavirus (crpv) infectivity. in all three virus infectivity systems, neu ... | 1990 | 1693698 |
| detection of papillomavirus dna in precancerous lesions of the ears of sheep. | sixty-seven benign precancerous cutaneous lesions from the ears of 51 sheep were examined for papillomavirus dna by hybridisation to radioactively labelled or biotinylated probes of bovine papillomavirus type 1 (bpv 1) dna under varying conditions of stringency. an additional 16 precancerous lesions from other cutaneous sites on 15 sheep and 15 samples of lesion-free skin from nine sheep were similarly examined. both total genomic and subgenomic probes were used. dna from 10 aural lesions and on ... | 1990 | 2177931 |
| distribution and specific identification of papillomavirus major capsid protein epitopes by immunocytochemistry and epitope scanning of synthetic peptides. | monoclonal (mabs) and polyclonal antibodies were produced against the major capsid protein of detergent-disrupted, purified bovine papillomavirus type 1 (bpv-1). the precise locations of the corresponding epitopes were identified by the reactivity of mabs and selected polyclonal antibodies with synthetic, overlapping, hexameric peptides corresponding with 95% of the bpv-1 major capsid protein. the topography of these epitopes was determined by reactivity of antibodies with intact (conformational ... | 1990 | 1700026 |
| an element in the bovine papillomavirus late 3' untranslated region reduces polyadenylated cytoplasmic rna levels. | expression of the two bovine papillomavirus type 1 (bpv-1) late genes, l1 and l2, coding for the two capsid proteins, is limited to terminally differentiated keratinocytes in bovine fibropapillomas. this pattern of expression is determined both by the activity of the late promoter and by the inhibition of late region expression in less well differentiated cells. inhibition of l1 and l2 mrna production in nonpermissive cells must occur since the late region potentially could be transcribed from e ... | 1991 | 1717710 |
| detection of papillomaviruses in cutaneous fibromas of white-tailed and mule deer. | naturally occurring cutaneous fibromas affecting white-tailed deer (odocoileus virginianus) and mule deer (o hemionus), and cutaneous fibropapillomas of domestic cattle were tested for papillomavirus using indirect immunofluorescence (if), peroxidase-antiperoxidase (pap), and negative-stain electron microscopic techniques. papillomavirus was consistently detected using rabbit antiserum against papillomavirus group-specific antigen in all mule deer fibromas and bovine fibropapillomas; only 16 of ... | 1985 | 2408523 |
| expression of the human papillomavirus type 6b l2 open reading frame in escherichia coli: l2-beta-galactosidase fusion proteins and their antigenic properties. | human papillomavirus (hpv) type 6b genome contains two large open reading frames (orfs), designated l1 and l2, in a putative late region. these orfs are expected to code for viral structural proteins. to examine antigenic properties of a l2 gene product, we constructed two plasmids which contain n-terminal (l2-n) and internal (l2-i) regions of the hpv6b l2 orf and then each region was expressed in escherichia coli as a fusion protein with e. coli beta-galactosidase (beta-gal). both l2-n/beta-gal ... | 1987 | 2437699 |
| replication of the bovine papillomavirus type 1 genome; antisense transcripts prevent episomal replication. | a subgenomic fragment, representing 69% of the bovine papillomavirus type 1 (bpv-1) genome, has the capacity to transform mouse c127 cells in vitro and to replicate episomally in these cells. in the present study we have cloned this bpv-1 fragment between two retrovirus-derived long terminal repeats (ltrs) in the two possible orientations. the constructs were designated pmr and pml. the pmr construct contained the bpv-1 genome in the same transcriptional orientation as that of the ltrs whereas t ... | 1986 | 2438189 |
| the 68-kilodalton e1 protein of bovine papillomavirus is a dna binding phosphoprotein which associates with the e2 transcriptional activator in vitro. | the e1 open reading frame of bovine papillomavirus type 1 encodes factors necessary for extrachromosomal maintenance of the viral genome in transformed cells. to facilitate biochemical characterization of the gene products encoded by this open reading frame, we have expressed the full-length e1 protein in a baculovirus-insect cell system. this protein was found to be phosphorylated and localized to the nucleus of infected cells. the e1 protein alone has affinity for dna but appears to lack speci ... | 1991 | 1846189 |
| characterization of the cis elements involved in basal and e2-transactivated expression of the bovine papillomavirus p2443 promoter. | transcriptional transactivation and repression by the viral e2 proteins are important regulatory mechanisms for the papillomaviruses. in the bovine papillomavirus type 1 (bpv-1), several viral promoters can be transactivated by e2 through e2-dependent enhancer elements located in the viral long control region (lcr), including promoters involved in e2 expression itself. this report demonstrates that the bpv-1 p2443 promoter is transactivated by e2-responsive elements in the lcr and that this prom ... | 1991 | 1846195 |
| expression in escherichia coli of seven dna fragments comprising the complete l1 and l2 open reading frames of human papillomavirus type 6b and localization of the 'common antigen' region. | molecular cloning was used to express human papillomavirus type 6b (hpv-6b) antigens in escherichia coli. seven genomic dna fragments of hpv-6b which together comprise the complete l1 and l2 open reading frames, known to code for capsid proteins, were cloned and expressed in e. coli as both beta-galactosidase and trpe fusion proteins. western blots of hpv-6b beta-galactosidase fusion proteins using 'genus-specific' antisera produced by immunization of rabbits with disrupted bovine papillomavirus ... | 1989 | 2471790 |
| identification of l2 open reading frame gene products of bovine papillomavirus type 1 using monoclonal antibodies. | four hybridoma cell lines producing monoclonal antibodies (mabs) to bovine papillomavirus type 1 (bpv-1) l2 open reading frame (orf) gene products have been established from mice immunized with a bpv-1 l2-beta-galactosidase fusion protein. hybridomas were selected and cloned (from over 700 hybridomas) on the basis of specific reactivity of supernatant fluids with bpv-1 l2 epitopes on disrupted bpv-1 particles and l2-beta-galactosidase fusion proteins by elisa and western blotting, and with aceto ... | 1989 | 2471804 |
| the human papillomavirus type 18 (hpv18) e2 gene product is a repressor of the hpv18 regulatory region in human keratinocytes. | the human papillomavirus type 18 (hpv18) long control region (lcr) harbors transcriptional promoter and enhancer elements. recombinant plasmids bearing all or part of the hpv18 lcr cloned in enhancer or promoter configuration upstream of the chloramphenicol acetyltransferase (cat) gene were transfected into human fibroblasts and keratinocytes. although the hpv18 enhancer can function in the absence of e2 gene products in both fibroblasts and keratinocytes, the promoter activity of the hpv18 lcr ... | 1989 | 2476572 |
| cooperative binding of the e2 protein of bovine papillomavirus to adjacent e2-responsive sequences. | the dna-binding properties of purified full-length e2 protein from bovine papillomavirus type 1 have been investigated by utilizing a quantitative gel shift analysis. by using a recombinant baculovirus which express the e2 open reading frame from the polyhedrin promoter, the full-length e2 protein was synthesized in insect cells and purified to homogeneity by using an e2 binding site (accgn4cggt)-specific oligonucleotide column. the kd of e2 binding to a 41-bp oligonucleotide containing a single ... | 1991 | 1848322 |
| the late region differentially regulates the in vitro transformation by cottontail rabbit papillomavirus dna in different cell types. | papilloma induced by the cottontail rabbit papillomavirus (crpv) progress at a high frequency to cancers. this property makes the crpv system unique to study the role of papillomaviruses in cancer development. in contrast to bovine papillomavirus type 1, no convenient in vitro transformation system for crpv has been available. here, we describe two in vitro systems that we have developed. transformation of nih 3t3 cells is greatly facilitated by deletions in the crpv late region. specifically, a ... | 1991 | 1849681 |
| direct interaction between sp1 and the bpv enhancer e2 protein mediates synergistic activation of transcription. | the physical interaction of heterologous site-specific dna-binding proteins is an important theme in eukaryotic transcriptional regulation. in this paper, we show that the cellular transcription factor sp1 and the bpv-1 (bovine papillomavirus type 1) enhancer protein e2 activate transcription synergistically from two papilloma viral promoters and a series of synthetic promoter constructs in transient transfection experiments. furthermore, sp1 can target e2 to a promoter region even in the absenc ... | 1991 | 1850324 |
| characterization of bovine papillomavirus e1 region deletion mutants associated with neoplastic transformation in a murine cell line. | spontaneous focus formation in the contact-inhibited c127 cell line, cl.2, harbouring multiple copies of a bovine papillomavirus type 1 deletion mutant, was associated with the evolution of further viral genomic deletions in addition to an amplification of the viral genome copy number. three simple frameshift deletions of 308, 605 and 1291 bp, associated with separate transformation events, were mapped within the e1 open reading frame, implying a common mechanism of spontaneous transformation in ... | 1991 | 1851818 |
| the bovine papillomavirus type 1 transcriptional activator e2 protein binds to its dna recognition sequence as a dimer. | the transcriptional trans-activator e2 protein from bovine papillomavirus type 1 has been shown to bind to the dna consensus sequence accn6ggt. we have produced the dna-binding domain of the e2 protein as a recombinant protein in escherichia coli. the e2 dna-binding domain was purified as two different molecular weight forms. using these purified proteins, we show that two molecules of the e2 protein bind to a single dna consensus binding site. | 1989 | 2538035 |
| an e1m--e2c fusion protein encoded by human papillomavirus type 11 is asequence-specific transcription repressor. | we have isolated a putative, spliced e5 cdna of human papillomavirus type 11 (hpv-11) by polymerase chain reaction amplification of cdnas from an experimental condyloma. using retrovirus-mediated gene transfer, we isolated two novel hpv-11 cdnas, one of which had a splice linking nucleotides 1272 and 3377. this transcript also existed in experimental condylomata and in cervical carcinoma cells transfected with cloned genomic hpv-11 dnas. the 5' end of the transcript in transfected cells originat ... | 1991 | 1851879 |
| papillomavirus infection of aged persian cats. | papillomavirus infection was confirmed in 2 persian cats with sessile hyperkeratotic skin lesions. skin lesions were not typical papillomas as found in other species. papillomavirus were demonstrated in negative stain preparations of homogenized tissue and within nuclei of cells in the stratum granulosum. papillomavirus group-specific antigens were detected within nuclei corresponding to those containing virions. attempts to transmit this disease to other cats or propagate the virus in tissue cu ... | 1990 | 1965634 |
| evidence for multiple vegetative dna replication origins and alternative replication mechanisms of bovine papillomavirus type 1. | by following up the chance detection in the electron microscope of a dna replication intermediate within a preparation of bovine papillomavirus (bpv-1) dna isolated from purified virus particles, information was obtained about the mechanism of bpv-1 genome replication during the final stages of virus multiplication in naturally infected bovine wart tissue. the structure of viral replication intermediates was investigated by electron microscopic analysis of viral dna linearized by digestion with ... | 1989 | 2539483 |
| the dna-binding domain of hpv-16 e2 protein interaction with the viral enhancer: protein-induced dna bending and role of the nonconserved core sequence in binding site affinity. | we expressed the carboxy-terminal portion of the e2 open reading frame (orf)-encoded protein of human papillomavirus type 16 (hpv-16) and purified it to near homogeneity. using dnase i footprinting techniques, we show that like the homologous protein from bovine papillomavirus type 1 (bpv-1), hpv-18, hpv-11, it binds dna at the enhancer consensus motif accn6ggt. base and phosphate backbone contact points were determined using methylation protection and interference and ethylation interference as ... | 1990 | 2154890 |
| sensitization of transformed rat cells to parvovirus mvmp is restricted to specific oncogenes. | the rat cell line fr3t3 was transformed with the retroviral oncogenes v-myc or v-src, with the dna tumor viruses sv40 or bovine papilloma virus strain 1 (bpv-1) or with the 69% transforming region of bpv-1. the transformants were compared with the uncloned parental line for their susceptibility to the lytic effect and to the replication of mvmp, an autonomous parvovirus. expression of v-myc and v-src proteins and of sv40 large t antigen correlated with a greater cell susceptibility to mvmp-induc ... | 1990 | 2157178 |
| selective enhancement of bovine papillomavirus type 1 dna replication in xenopus laevis eggs by the e6 gene product. | genetic analyses of bovine papillomavirus type 1 (bpv-1) dna in transformed mammalian cells have indicated that the e6 gene product is essential for the establishment and maintenance of a high plasmid copy number. in order to analyze the direct effect of the e6 protein on the replication of a bpv-1-derived plasmid, a cdna containing the bpv-1 e6 open reading frame was subcloned into an sp6 vector for the in vitro synthesis of the corresponding mrna. the sp6 e6 mrna was injected into xenopus laev ... | 1989 | 2540419 |
| successive steps in the process of immortalization identified by transfer of separate bovine papillomavirus genes into rat fibroblasts. | transfer of neor and bovine papillomavirus type 1 (bpv1) dna into rat embryo fibroblasts led to colony formation in g418-containing medium, with no detectable background in controls with neor dna alone. more than 50% of the drug-resistant clones could be further propagated in culture. the genetic functions of bpv1 involved in colony formation and in long-term immortalization were investigated by both translation termination mutations in the full-length genome, which inactivate individual open re ... | 1989 | 2541438 |
| mutational analysis of cis elements involved in e2 modulation of human papillomavirus type 16 p97 and type 18 p105 promoters. | cis-acting elements involved in e2 modulation of human papillomavirus type 16 (hpv-16) p97 promoter activity and hpv-18 p105 promoter activity were examined. in transfected primary human keratinocytes, each promoter had a basal activity that could be repressed by the bovine papillomavirus type 1 e2 gene product. mutational analysis of the e2-binding sites in the long control region upstream of each promoter revealed that e2 repression was mediated through the e2-binding sites proximal to each pr ... | 1990 | 2159546 |
| transforming growth factor-beta expression in fibropapillomas induced by bovine papillomavirus type 1, in normal bovine skin, and in bpv-1-transformed cells. | there is substantial evidence to suggest that transforming growth factor-beta (tgf-beta) plays an important role in wound healing and tissue repair as well as in carcinogenesis. it has also been observed that naturally occurring bovine papillomavirus type 1 (bpv-1)-induced bovine fibropapillomas occur predominantly at traumatized sites of the body, suggesting that humoral factors released in wounds might be important for papillomavirus infection. we have therefore investigated the possible role ... | 1990 | 2160257 |
| cell-heritable stages of tumor progression in transgenic mice harboring the bovine papillomavirus type 1 genome. | tumorigenesis of dermal fibroblasts in a line of transgenic mice carrying the bpv-1 genome was found to involve distinct proliferative stages. cell cultures derived from normal skin, from benign proliferative fibromatoses, and from malignant fibrosarcomas each evidenced distinguishable, cell-heritable characteristics. the latent viral genome was transcriptionally inactive in normal-appearing skin and was activated in the dermal fibromatoses. fibrosarcoma cells grew continuously in culture, forme ... | 1989 | 2542769 |
| evidence that replication initiates at only some of the potential origins in each oligomeric form of bovine papillomavirus type 1 dna. | in a subclone of id13 mouse fibroblasts latently infected with bovine papillomavirus type 1 (bpv-1) dna, the viral genome occurred as a mixture of extrachromosomal circular monomers and oligomers. multiple copies were also associated with the host cell genome, predominantly at a single site in a head-to-tail tandem array. we examined the replicative intermediates of extrachromosomal forms of bpv-1 dna by using two-dimensional gel electrophoresis. the results obtained indicate that initiation of ... | 1990 | 2160593 |
| the e2 transactivator of bovine papillomavirus type 1 is expressed from multiple promoters. | the e2 proteins of bovine papillomavirus type 1 (bpv-1) are a family of site-specific dna-binding proteins which regulate viral transcription by repression and activation. repressors e2-tr and e8/e2 are expressed from promoters p5 (p3080) and p3 (p890), respectively. previous reports have provided evidence that the transcript for the 48-kilodalton transactivator is initiated from a promoter proximal to the open reading frame encoding this protein (p2440 or p4). our studies extend these findings ... | 1990 | 2164604 |
| cooperative activation of transcription by bovine papillomavirus type 1 e2 can occur over a large distance. | the viral transcriptional factors encoded by the e2 open reading frame bind to the specific dna sequence elements accgnnnncggt, allowing activation or repression of transcription. we have analyzed bovine papillomavirus type 1 e2 transactivation using recombinant genes containing e2-binding sites inserted at either 3' or 5' positions relative to the heterologous transcriptional initiation site of the herpes simplex virus thymidine kinase gene. in these hybrid plasmids, strong transactivation requ ... | 1990 | 2164642 |
| a bovine papillomavirus constitutive enhancer is negatively regulated by the e2 repressor through competitive binding for a cellular factor. | the bovine papillomavirus type 1 long control region (lcr) contains dna sequence elements involved in the regulation of viral transcription and replication. differences in the levels of transcription have previously been noted between bovine papillomavirus type 1-infected rodent cell lines and bovine cells. to investigate these differences, fragments of the lcr were cloned into an enhancer-deleted chloramphenicol acetyltransferase expression vector and assayed for enhancer activity. a strong con ... | 1990 | 2170679 |
| replication of bovine papillomavirus type 1 dna initiates within an e2-responsive enhancer element. | when bovine papillomavirus transforms cells in vitro, it maintains its genome as a multicopy nuclear plasmid. plasmid dna extracted from such transformed cells was analyzed by the two-dimensional gel electrophoresis technique of brewer and fangman (b. brewer and w. fangman, cell 51:463-471, 1987). the replication intermediates detected in these assays were found to be the sums of the oligomeric and monomeric forms of the replicating plasmids. the multimeric dnas were shown by field inversion gel ... | 1990 | 2173772 |
| proteins encoded by the bovine papillomavirus e1 open reading frame: expression in heterologous systems and in virally transformed cells. | the e1 open reading frame (orf) of bovine papillomavirus type 1 is required for the persistence of viral genomes as multicopy plasmid molecules in transformed rodent fibroblasts. e1 has been reported to contain two separate complementation groups (m and r, corresponding to n- and c-terminal domains, respectively) which regulate viral replication. however, e1 behaves as a single gene with respect to cell transformation and viral transcription. we examined the proteins translated from the entire o ... | 1990 | 2173778 |
| local immune reaction in syngeneic mice against tumorigenic and nontumorigenic bpv-transformed mouse cell lines. | the role of cytotoxic t cells in immune response to bovine papillomavirus type 1 (bpv1)-transformed mouse cell lines was assessed. the chromium release assay was used to follow the induction of cytotoxicity in local lymph nodes of syngeneic c57bl/6j (b6) mice after injection of bpv1-transformed cell lines tumorigenic in nude mice but tumorigenic or nontumorigenic in b6 mice. the nontumorigenic cell line b6b31.c-nut.a induced cell line-specific cytotoxicity with a maximal activity on day 7 after ... | 1990 | 2173935 |
| transforming activity of a 16-amino-acid segment of the bovine papillomavirus e5 protein linked to random sequences of hydrophobic amino acids. | the 44-amino-acid e5 protein of bovine papillomavirus type 1 is the smallest transforming protein yet described. previous results from our laboratory indicate that a hydrophobic core and specific carboxyl-terminal amino acids are required for the e5 protein to exert its transforming function. in this study, additional substitution mutations were generated in the e5 gene to determine the minimal amino acid sequence requirements for focus formation in mouse c127 cells. in most cases examined, subs ... | 1989 | 2552136 |
| non-selective analysis of the transformation of fr3t3 rat cells by bovine papillomavirus type 1: regulations of viral transcription associated with phenotypic transformation. | drug-resistant clones selected from fr3t3 rat cells after transfer of neo-bpv1 (bovine papillomavirus type 1) dna constructs became phenotypically transformed (focal transformation, growth in suspension and tumor formation) soon after selection (approximately 5 generations in culture). a frameshift mutation in orf e5 abolished transformation, but did not prevent the autonomous maintenance of the dna construct. a more complex situation was observed when the e2 transactivating function was abrogat ... | 1990 | 2176280 |
| nutritional requirements of papillomavirus-transformed mouse cells and an uninfected parent line in serum-free culture. | a serum-free culture system was used to compare the nutritional requirements of mouse mammary cells transformed by bovine papillomavirus type 1 (id13 cells) and the uninfected parent line (c127 cells). the serum-free, chemically defined medium used for this study was an mcdb 151-based medium (mcdb 151+s+i), supplemented with epidermal growth factor, transferrin, hydrocortisone, ethanolamine, phosphoethanolamine, retinoic acid, trace metals, and insulin. proliferation of either cell type in serum ... | 1989 | 2553658 |
| effects of changes in calmodulin levels on cell proliferation. | calmodulin (cam) is one of several proteins regulated in a cell cycle-dependent manner. cam is synthesized at the g1/s boundary and has been implicated in the regulation of cell cycle progression. to elucidate the role of calmodulin in cell cycle control, clonal mouse c127 cell lines transformed with one of four different bovine papilloma virus (bpv)-based vectors were studied. these vectors express a) a chicken cam gene regulated by its own promoter (cm cells), b) the chicken cam gene regulated ... | 1990 | 2190816 |
| altered synthesis of the 26-kda heat stress protein family and thermotolerance in cell lines with elevated levels of calcium-binding proteins. | using a bovine papilloma virus-based vector, mouse mammary adenocarcinoma cells have been transformed to express elevated amounts of functional calmodulin (cam) (rasmussen and means, 1987) and another ca2(+)-binding protein, parvalbumin (pv) (rasmussen and means, 1989) that is not normally synthesized in these cells. parental cells (c127) and cells transformed by the vector alone (bpv-1), the vector containing a cam gene (cm-1), or the vector containing parvalbumin (pv-1) were used to study the ... | 1990 | 2312618 |
| topographical and conformational epitopes of bovine papillomavirus type 1 defined by monoclonal antibodies. | monoclonal antibodies (mabs) were generated against sodium dodecyl sulfate-disrupted bovine papillomavirus type 1 (bpv-1). when screened by enzyme-linked immunosorbent assay (elisa) on intact and disrupted bpv-1, -2, and deer papillomavirus, three patterns of reactivity were defined: reactivity only with intact virus, with both intact and disrupted virus, and only with disrupted virus. on the basis of elisa results, the topographical location and requirement for conformation for immunoreactivity ... | 1987 | 2446044 |
| human antibodies react with an epitope of the human papillomavirus type 6b l1 open reading frame which is distinct from the type-common epitope. | recombinant proteins encoded by the human papillomavirus type 6b (hpv6b) l1 open reading frame react with sera from patients with condylomata acuminata and also react with rabbit antiserum raised against sodium dodecyl sulfate-disrupted bovine papillomavirus type 1 (bpv1) virions. to map the immunoreactive epitopes, a series of procaryotic expression plasmids was made which contained a nested set of 3' to 5' deletions in the hpv6b l1 open reading frame. the deleted plasmids expressed a set of ca ... | 1989 | 2463384 |
| tumorigenicity, invasiveness and metastatic capability of fr3t3 rat cells before and after transfection with bovine papilloma virus type 1 dna. | fischer rat fr3t3 cells were tested for tumorigenicity, invasive and metastatic capabilities before and after transfection, either with the entire bovine papilloma virus type 1 (bpv-1) genome or with a plasmid (pv69) containing a 69 per cent bam h1-hind iii fragment of the bpv-1 genome as well as bacterial sequences. cell lines were grouped as parental, pv69-transfectants, bpv-1 transfectants, in vitro derivatives, and in vivo derivatives. the tumorigenic, invasive and metastatic capabilities of ... | 1989 | 2535681 |
| open reading frames e6 and e7 of bovine papillomavirus type 1 are both required for full transformation of mouse c127 cells. | a series of mutations in open reading frames (orfs) e6 and e7 of bovine papillomavirus type 1 (bpv1) was constructed to analyze the roles of these orfs in transformation of mouse c127 cells. the mutations were designed to prevent synthesis of specific proteins encoded by these genes. none of the mutations caused a decrease in the focus-forming activity of the full-length viral genome or in the ability of the viral dna to replicate as a high-copy-number plasmid. analysis of these mutants in the a ... | 1989 | 2535732 |
| e2 polypeptides encoded by bovine papillomavirus type 1 form dimers through the common carboxyl-terminal domain: transactivation is mediated by the conserved amino-terminal domain. | the e2 open reading frame (orf) of bovine papillomavirus type 1 (bpv-1) encodes positive- and negative-acting factors that regulate viral gene expression. the full-length orf encodes a transactivator, and two transcriptional repressors are expressed from the 3' half of the orf. previous analysis has shown that a conserved c-terminal region of 101 amino acids, which is shared by e2 transactivator and repressor proteins, contains the specific dna binding activity. further analysis of the e2 transa ... | 1989 | 2536165 |
| reindeer papillomavirus transforming properties correlate with a highly conserved e5 region. | a papillomavirus was isolated from the epithelial layer of a cutaneous fibropapilloma on a swedish reindeer (rangifer tarandus). reindeer papillomavirus (rpv) is morphologically indistinguishable from other papillomaviruses, but the restriction enzyme cleavage pattern of its genome is different. no sequence homology was detected between rpv dna and the dnas of bovine papillomavirus type 1 (bpv-1) and avian papillomavirus when hybridization was performed under stringent conditions. however, the r ... | 1987 | 2822949 |
| papillomavirus polypeptides e6 and e7 are zinc-binding proteins. | papillomavirus proteins e6 and e7 have cys-x-x-cys repeats which have been suggested to mediate zinc binding. we have developed a modification of an assay that detects zinc binding to proteins immobilized on filters. using well-characterized metalloproteins, we show that, under reducing conditions, this assay distinguishes proteins that coordinate zinc through cysteine residues from those that bind the metal through other amino acids. under these conditions, e6 and e7 polypeptides of human papil ... | 1989 | 2536841 |
| bovine papillomavirus type 1 encodes two forms of a transcriptional repressor: structural and functional analysis of new viral cdnas. | genetic and biochemical evidence has established that the e2 open reading frame (orf) of bovine papillomavirus type 1 encodes at least two different site-specific dna-binding proteins, one which activates and the other which represses expression from a viral promoter (p. f. lambert, b. a. spalholz, and p. m. howley, cell 50:69-78, 1987). we have obtained data which show that a second form of the repressor gene is expressed in transformed cells harboring stable viral plasmids. the structural deta ... | 1989 | 2538655 |
| identification of bovine papillomavirus e1 mutants with increased transforming and transcriptional activity. | the e1 open reading frame of bovine papillomavirus type 1 (bpv) has been shown previously to encode trans-acting functions, m and r, that are involved in extrachromosomal replication of the viral genome. we have determined that several e1 mutants mapping in both the m and r regions and a single mutant of the upstream regulatory region have a higher transforming activity on mouse c127 cells than the wild-type genome does. a representative mutant in m, a mutant in r, and the upstream regulatory re ... | 1989 | 2538656 |
| bovine papillomavirus e2 repressor mutant displays a high-copy-number phenotype and enhanced transforming activity. | the methionine codon at bovine papillomavirus type 1 nucleotide 3091 was mutated to determine whether it may serve as an initiation codon for an e2 transcriptional repressor protein and to determine the role of the repressor in the biological activities of the virus. a series of transient expression experiments with cv1 cells documented that the mutation reduced expression of repressor activity from the viral genome and resulted in increased expression of the e5 transforming gene. viral genomes ... | 1990 | 2153255 |
| messenger rnas from the e1 region of bovine papillomavirus type 1 detected in virus-infected bovine cells. | bovine papillomavirus type 1 dna replicated to a high copy number in virus-infected bovine fibroblasts. infected bovine cells were therefore used as a source of rna for northern blotting analysis to search for viral transcripts hybridizing to the e1 gene region, implicated in viral dna replication. cytoplasmic polyadenylated rna preparations contained at least five different e1-region transcripts, ranging from 1200 to approximately 4500 nucleotides in length. all of these species contained seque ... | 1987 | 2825116 |