Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| p3 promoter element of bovine papillomavirus. | the p3 promoter activity of bovine papillomavirus (bpv) and cis-acting dna element of p3 promoter required for transcription were examined using chloramphenicol acetyltransferase (cat) assay. the results show that p3 promoter is a very weak promoter compared to p2 promoter in bpv and e2 transactivator is required for the maximal transcription of p3 promoter in a bpv upstream regulatory region (urr)-dependent manner. deletion experiments by nuclease bal-31 were carried out to define p3 promoter e ... | 1993 | 8390322 |
| the acidic transcriptional activation domains of vp16 and p53 bind the cellular replication protein a and stimulate in vitro bpv-1 dna replication. | for papillomavirus dna replication, the e2 enhancer protein cooperatively assists in binding of the e1 helicase to the origin. we report that, at limiting e1 and e2 levels, the enhancer proteins gal4-vp16 and gal4-p53(1-73) stimulate bpv in vitro dna replication. this cell-free system was used to ascertain whether the acidic activation domains have a cellular target important for replication. cellular extracts were depleted of replication activity by passage through a vp16 affinity column. the p ... | 1993 | 8390328 |
| cooperative assembly of the bovine papilloma virus e1 and e2 proteins on the replication origin requires an intact e2 binding site. | using quantitative gel retardation assays the properties of the bovine papilloma virus (bpv) origin recognition protein e1 and the effect of the viral e2 protein on the binding of e1 to bpv origin dna were examined. as reported previously (seo, y.s., mueller, f., lusky, m., gibbs, e., kim, h.-y., phillips, b. and j. hurwitz (1993) proc. natl. acad. sci. u. s. a. 90, 2865-2869), the e1 protein binds specifically to dna sequences within the bpv origin (ori+) of replication. we also show that the p ... | 1993 | 8393453 |
| a study from south india on the association between the papilloma virus and carcinoma of the penis. | specimens from 39 cases of squamous cell carcinoma of the penis were treated for the papilloma virus using the bovine papilloma virus antibody and the peroxidase-antiperoxidase technique. all 39 cases showed a viral antigen situated intranuclearly, intracytoplasmically or both intranuclearly and intracytoplasmically. no correlation could be seen between the presence of viral antigen and age of patient, duration of lesion, cell morphology and histological grade. the adjacent mucosa and skin were ... | 1993 | 8393502 |
| repression of bovine papillomavirus type 1 transcription by the e1 replication protein. | bovine papillomavirus type 1 (bpv-1) is the prototype virus for the study of papillomavirus gene regulation. the functions of the bpv-1 e2 proteins in transcriptional regulation have been well characterized. the bpv-1 e1 protein is required for viral dna replication and can bind to the origin of replication alone or in a complex with the e2 transactivator protein. in this study, we demonstrated that the bpv-1 e1 protein is also involved in transcriptional regulation. the e1 protein significantly ... | 1993 | 8394436 |
| transformation-specific interaction of the bovine papillomavirus e5 oncoprotein with the platelet-derived growth factor receptor transmembrane domain and the epidermal growth factor receptor cytoplasmic domain. | the bovine papillomavirus e5 transforming protein appears to activate both the epidermal growth factor receptor (egf-r) and the platelet-derived growth factor receptor (pdgf-r) by a ligand-independent mechanism. to further investigate the ability of e5 to activate receptors of different classes and to determine whether this stimulation occurs through the extracellular domain required for ligand activation, we constructed chimeric genes encoding pdgf-r and egf-r by interchanging the extracellular ... | 1993 | 8394451 |
| differentiation-specific expression from the bovine papillomavirus type 1 p2443 and late promoters. | the papillomavirus life cycle is tightly linked with keratinocyte differentiation in squamous epithelia. vegetative viral dna replication begins in the spinous layer, while synthesis of capsid proteins and virus maturation is restricted to the most differentiated or granular layer of the epithelium. in this study, in situ hybridization of bovine fibropapillomas was used to demonstrate that the activity of two promoters of bovine papillomavirus type 1 (bpv-1) is regulated in a differentiation-spe ... | 1993 | 8394463 |
| cooperative dna binding of the bovine papillomavirus e2 transcriptional activator is antagonized by truncated e2 polypeptides. | cooperative dna binding of the bovine papillomavirus type 1 (bpv-1) e2 transcriptional activator (e2-ta) is thought to play a role in the transcriptional synergism of multiple e2-responsive dna elements (j. ham, n. dostatni, j.-m. gauthier, and m. yaniv, trends biochem. sci. 16:440-444, 1991). binding-equilibrium considerations show that such involvement is unlikely, thereby suggesting that the e2-ta cooperative capacity may have evolved to play other, different roles. the role of cooperative in ... | 1993 | 8394466 |
| dna of bovine papillomavirus type 1 and 2 in equine sarcoids: pcr detection and direct sequencing. | nucleotide sequences of bovine papillomavirus (bpv) dna amplified by the polymerase chain reaction (pcr) from samples of equine sarcoid skin tumours were determined. all naturally occurring sarcoids (n = 58 tumours from 32 horses and 2 donkeys) contained bpv-dna. all but 3 of the genome fragments belonged to the bpv type 1 strain (bpv-1); the remaining were bpv type 2. similar results were obtained with cutaneous bovine papillomas used as controls (n = 20). one of the horses, carrying 2 sarcoids ... | 1993 | 8394687 |
| dna-binding domain of bovine papillomavirus type 1 e1 helicase: structural and functional aspects. | the e1 protein of bovine papillomavirus type 1 is a multifunctional enzyme required for papillomaviral dna replication. it assists in the initiation of replication both as a site-specific dna-binding protein and as a dna helicase. previous work has indicated that at limiting e1 concentrations, the e2 protein is required for efficient e1 binding to the replication origin. in this study, we have defined the domain of the e1 protein required for site-specific dna binding. experiments with a series ... | 1993 | 8396665 |
| importance of the bovine papillomavirus p2443 promoter in the regulation of e2 and e5 expression. | the full-length bovine papillomavirus e2 gene product (e2ta), which has a direct role in dna replication and functions as a transcriptional activator, can be expressed from an unspliced mrna transcribed from the p2443 promoter or from spliced mrnas transcribed from other upstream promoters. the regulation of e2 expression from these promoters is still in question. in the background of wild-type protein coding sequences, this study identified the p2443 promoter as the major source of e2ta as well ... | 1993 | 8396681 |
| human papillomavirus and cutaneous warts in meat handlers. | the association of papillomavirus and hand warts in meat handlers was examined. human papillomavirus (hpv) dna was found in 23 (88%) of 26 cutaneous warts, with hpv 7 (27%) and a yet unidentified hpv (hpv x) (42%) being the predominant types. hpv 2 was found in two (7.5%) patients, and hpv 4 was found in three (11.5%) patients. no bovine papillomavirus sequences were detected. in most patients, the warts developed in less than 2 years after they started working with meat. a possible hpv transmis ... | 1993 | 8408588 |
| interaction between bovine papillomavirus type 4 and cocarcinogens in the production of malignant tumours. | bovine fetal palatine tissue infected with bovine papillomavirus type 4 (bpv-4) was implanted subcutaneously in athymic nude mice. the implants developed into cysts containing papillomas essentially the same as those in the natural host. in order to investigate the interaction of cocarcinogens with bpv-4 in cell transformation, the virus-infected implants were exposed in vivo to either the tumour promoter 12-o-tetradecanoylphorbol-13-acetate (tpa) or the tumour initiator 7,12-dimethylbenz[a]-ant ... | 1993 | 8409951 |
| the conserved c-terminal domain of the bovine papillomavirus e5 oncoprotein can associate with an alpha-adaptin-like molecule: a possible link between growth factor receptors and viral transformation. | the bovine papillomavirus e5 gene encodes an oncoprotein that can independently transform rodent fibroblasts. this small 44-amino-acid protein is thought to function through the activation of growth factor receptors. e5 activation of the epidermal growth factor receptor results in an increase in the number of activated receptors at the cell surface. this finding suggests that e5 may act by inhibiting the normal down regulation of activated epidermal growth factor receptor via coated pit-mediated ... | 1993 | 8413245 |
| alanine mutagenesis of conserved residues in the platelet-derived growth factor family: identification of residues necessary for dimerization and transformation. | platelet-derived growth factor (pdgf) and vascular endothelial growth factor define a family of dimeric proteins characterized by eight conserved cysteine residues involved in disulfide bonds. thirteen non-cysteine residues conserved among the platelet-derived/vascular endothelial growth factors were individually mutated to alanine in v-sis/pdgf-b. in addition, five other residues flanking f148 were also mutated to alanine. the resulting mutants were assayed for transformation of nih3t3 cells, a ... | 1993 | 8437840 |
| the p12i, p13ii, and p30ii proteins encoded by human t-cell leukemia/lymphotropic virus type i open reading frames i and ii are localized in three different cellular compartments. | three protein isoforms are encoded by the human t-cell leukemia/lymphotropic virus type i px region open reading frames (orf) i and ii through alternative splicing. both the singly and doubly spliced mrnas from orf i encode a single 12-kda protein (p12i), whereas two distinct proteins of 13 kda (p13ii) and 30 kda (p30ii) are encoded from the orf ii alternatively spliced mrna. because the p12i protein is very hydrophobic and poorly immunogenic, we genetically engineered its cdna by adding a short ... | 1993 | 8445734 |
| e1 protein of human papillomavirus is a dna helicase/atpase. | replication of human papillomavirus (hpv) dna requires the viral proteins e1 and e2. amino acid similarities to sv40 large-t antigen had suggested that e1 is a dna helicase/atpase involved in initiating viral dna replication, and this has recently been shown for bovine papillomavirus type 1 (bpv-1) e1 protein. however, in vitro analysis of hpv e1 has been hampered by the inability to produce purified protein using heterologous expression systems. we have succeeded in demonstrating atpase and dna ... | 1993 | 8290339 |
| protein-sulfenic acid stabilization and function in enzyme catalysis and gene regulation. | sulfenic acids (r-soh) result from the stoichiometric oxidations of thiols with mild oxidants such as h2o2; in solution, however, these derivatives accumulate only transiently due to rapid self-condensation reactions, further oxidations to the sulfinic and/or sulfonic acids, and reactions with nucleophiles such as r-sh. in contrast, oxidations of cysteinyl side chains in proteins, where disulfide bond formation can be prevented and where the reactivity of the nascent cysteine-sulfenic acid (cys- ... | 1993 | 8262333 |
| mapping of linear b cell epitopes on capsid proteins of bovine papillomavirus: identification of three external type-restricted epitopes. | immunodominant, conserved and type-restricted external epitopes of bovine papillomavirus (bpv) major (l1) capsid protein have been identified using bpv particles and synthetic peptides. antisera to disrupted bpv-1 recognized bpv-1 and bpv-2 particles in immune electron microscopy (iem) studies and inhibited bpv-2-induced focus formation of nih/3t3 cells. thus bpv-1/bpv-2 cross-reactive epitopes occur on the surface of virions. the l1 protein appeared to be immunodominant as the antisera reacted ... | 1993 | 8277272 |
| activation of eukaryotic transcriptional promoters by the bovine papillomavirus e1-replication factor. | it has been suggested that the bovine papillomavirus type 1 e1 replication factor may inhibit e2-conditional gene expression from viral promoter p89. to study the possible role of the e1 protein in gene expression, hela cells were transfected with e2-conditional or e2-independent reporter plasmids and with vectors expressing the e1 and e2 open reading frames. the data show that: (i) replication factor e1 stimulates gene expression from a variety of eucaryotic transcriptional promoters; (ii) acti ... | 1993 | 8169116 |
| monoclonal antibody neutralization of bpv-1. | mouse monoclonal antibodies were generated against intact infectious bpv-1 virions by methods previously described (christensen et al., 1990). elisa was used to screen for reactivities to intact and/or disrupted bpv-1, crpv and hpv-11 virions. several hybridomas were initially selected that showed antibody reactivity by elisa to both intact and disrupted bpv-1, to disrupted bpv-1 only, or to intact bpv-1 virions. one monoclonal antibody, designated b1.a1, which reacted only to intact bpv-1 was s ... | 1993 | 7686316 |
| the human papillomavirus type 6 and 16 e5 proteins are membrane-associated proteins which associate with the 16-kilodalton pore-forming protein. | the human papillomavirus (hpv) e5 proteins are predicted from dna sequence analysis to be small hydrophobic molecules, and the hpv type 6 (hpv-6) and hpv-11 e5 proteins share several structural similarities with the bovine papillomavirus type 1 (bpv-1) e5 protein. also similar to the bpv-1 e5 protein, the hpv-6 and hpv-16 e5 proteins exhibit transforming activity when assayed on nih 3t3 and c127 cells. in this study, we expressed epitope-tagged e5 proteins from both the "low-risk" hpv-6 and the ... | 1993 | 7690419 |
| site-specific dna-binding proteins important for replication and transcription have multiple activities. | 1993 | 7956054 | |
| site-specific initiation of dna replication in metazoan chromosomes and the role of nuclear organization. | we have asked whether or not xenopus eggs or egg extracts, which have previously been shown to replicate essentially any dna molecule, will preferentially utilize a known mammalian obr. our results reveal that xenopus egg extracts can preferentially initiate dna replication at sites chosen in vivo by the hamster cell, provided that the dna substrate is presented to the extract in the form of a nucleus rather than bare dna. thus, site-specific initiation of dna replication in metazoan cell chromo ... | 1993 | 7956062 |
| 1h nmr studies of the mercuric ion binding protein merp: sequential assignment, secondary structure and global fold of oxidized merp. | the oxidized form of the mercuric ion binding protein merp has been studied by two-dimensional nmr. merp, which is a periplasmic water-soluble protein with 72 amino acids, is involved in the detoxification of mercuric ions in bacteria with resistance against mercury. the mercuric ions in the periplasmic space are first scavenged by the merp protein, then transported into the cytoplasm by the membrane-bound transport protein mert, and finally reduced to elementary (nontoxic) mercury by the enzyme ... | 1993 | 8111228 |
| the tryptophan bridge is a critical feature of the papillomavirus e2 dna binding domain. | the papillomavirus e2 protein is a dna binding protein that regulates viral transcription and replication. e2 binds dna as a dimer. recent crystallographic data for e2 complexed to dna revealed that novel peptide structures in e2 mediated dimerization and dna binding. to identify important features of these motifs we have used limited proteolysis and urea denaturation as biochemical probes for structure, applying these techniques to e2 alone, e2 bound to dna, cross-linked products, and mutants t ... | 1993 | 8212573 |
| identification of conformational epitopes of the bpv-1 capsid recognized by competitive inhibition of sera from infected or immunized animals. | conformational papillomavirus (pv) capsid epitopes are the major targets of neutralizing antibodies. bpv1 virion surface epitopes were analyzed for type-specificity, induction of neutralization, and topographical location with antibodies from selected humans, and bpv1 or -2 immunized or infected cattle, rabbits and mice. rabbit sera produced against deer pv (dpv) or bpv2 and human sera reacted with intact bpv1 in elisa, indicating the presence of cross-reactive conformational epitopes on the sur ... | 1993 | 8216835 |
| effect of gamma-interferon or cycloheximide treatment on viral and c-myc transcripts in bovine-papillomavirus-type-1-transformed primary mouse fibroblasts. | we have studied the effect of gamma-interferon (ifn-gamma) treatment on the transcription of viral and c-myc oncogenes in bovine papillomavirus type 1 (bpv-1)-transformed mouse fibroblast cell lines. upon ifn-gamma treatment, viral transcripts always decreased in cell lines containing episomal bpv-1 dna, while the effect was variable in cell lines containing integrated bpv-1 dna. two series of tumour cell lines established by in vivo passage of b6b71 (episomal) and b6b31-j (integrated) cells via ... | 1993 | 8225910 |
| the v-sis protein retains biological activity as a type ii membrane protein when anchored by various signal-anchor domains, including the hydrophobic domain of the bovine papilloma virus e5 oncoprotein. | membrane-anchored forms of the v-sis oncoprotein have been previously described which are oriented as type i transmembrane proteins and which efficiently induce autocrine transformation. several examples of naturally occurring membrane-anchored growth factors have been identified, but all exhibit a type i orientation. in this work, we wished to construct and characterize membrane-anchored growth factors with a type ii orientation. these experiments were designed to determine whether type ii memb ... | 1993 | 8227125 |
| detection of human papillomavirus l1 protein in condylomata acuminata from adults with defects in cell-mediated immunity. | immunohistochemical assays for human papillomavirus (hpv) l1 protein, using antiserum directed against the l1 major capsid protein of bovine papillomavirus (anti-bpv serum), were performed on 101 condylomata acuminata biopsy samples from 47 men (40 of whom had intact cell mediated immunity [cmi], and 7 with conditions known to cause cmi defects), and 54 women (48 with normal cmi, and 6 with cmi defects). l1 protein was detected in 28% of all biopsies, including 20.5% of samples from patients wit ... | 1993 | 8228942 |
| two e2 binding sites (e2bs) alone or one e2bs plus an a/t-rich region are minimal requirements for the replication of the human papillomavirus type 11 origin. | human papillomaviruses (hpvs) cannot be propagated in vitro, but the dna can be replicated transiently in an assay in the presence of two trans-acting viral proteins, e1 and e2. using this assay, we have defined the minimal cis-acting elements of the origin of replication of hpv type 11. most hpv genomes are conserved at the origin of replication, and the core contains three e2 binding sites (e2bs) surrounding an a/t-rich spacer region. the present results show that the minimal requirement for r ... | 1993 | 8230435 |
| the human t-cell leukemia/lymphotropic virus type i p12i protein cooperates with the e5 oncoprotein of bovine papillomavirus in cell transformation and binds the 16-kilodalton subunit of the vacuolar h+ atpase. | the human t-cell leukemia/lymphotropic virus type i (htlv-i) induces t-cell leukemia and transforms human t cells in vitro. a recently identified protein with a molecular weight of 12,000 (12k) (p12i), encoded by single- and double-spliced mrnas transcribed from the 3' end of the htlv-i genome, has been shown to localize in the perinuclear compartment and in the cellular endomembranes. the p12i protein exhibits significant amino acid sequence similarity to the e5 oncoprotein of bovine papillomav ... | 1993 | 8230493 |
| enrichment for metallothionein does not confer resistance to cisplatin in transfected nih/3t3 cells. | evidence has been presented both that metallothionein does and does not produce resistance to cisplatin. the metallothionein-enriched cells described in most previous studies have been selected for resistance to heavy metals, such as cadmium, or have been maintained in a medium enriched for the metals. exposure to toxic metals could alter the cells in many ways. this report addresses the effect of metallothionein content alone, independent of exposure to metals, on cellular resistance to cisplat ... | 1993 | 8246143 |
| hierarchy of polyadenylation site usage by bovine papillomavirus in transformed mouse cells. | the great majority of viral mrnas in mouse c127 cells transformed by bovine papillomavirus type 1 (bpv) have a common 3' end at the early polyadenylation site which is 23 nucleotides (nt) downstream of a canonical poly(a) consensus signal. twenty percent of bpv mrna from productively infected cells bypasses the early polyadenylation site and uses the late polyadenylation site approximately 3,000 nt downstream. to inactivate the bpv early polyadenylation site, the early poly(a) consensus signal w ... | 1993 | 7901430 |
| partite expression of the bovine papillomavirus e1 open reading frame in escherichia coli. | six recombinants were constructed which expressed portions of the bovine papillomavirus e1 open reading frame as ompf/e1/beta-galactosidase tribrid fusion proteins in escherichia coli. rabbit sera containing e1-specific antibodies were generated against five of these six fusion proteins (which together constitute 74% of the full-length e1 open reading frame). the individual fusion proteins and their cognate antisera will be useful reagents for defining the structure and function of the bpv e1 pr ... | 1992 | 1309664 |
| amino acids necessary for dna contact and dimerization imply novel motifs in the papillomavirus e2 trans-activator. | the bovine papillomavirus e2 protein regulates viral transcription by binding as a dimer to the dna sequence accgn4cggt. the dimerization and dna-binding properties are localized within its carboxy-terminal 85 amino acids (325-410). utilizing random mutagenesis coupled with phenotypic selection in yeast, functionally important amino acids in the dna-binding domain were identified. four trans-activation defective point mutants within a short segment (amino acids 337-344) were dna binding defectiv ... | 1992 | 1309714 |
| 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 |
| uptake of cadmium is diminished in transfected mouse nih/3t3 cells enriched for metallothionein. | to determine the relationship between cellular uptake of cadmium and content of metallothionein, we measured uptake of 109cd in cells that differed in content of metallothionein (mt). mt cells were derived from nih/3t3 cells by transfection with a plasmid containing the genome of bovine papilloma virus and the mouse metallothionein-i gene, driven by the promotor for the glucose-regulated protein of 78 kda. control cells were similarly transfected with bovine papilloma virus-based plasmids with t ... | 1992 | 1310676 |
| 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 |
| during negative regulation of the human papillomavirus-16 e6 promoter, the viral e2 protein can displace sp1 from a proximal promoter element. | the principal early promoter of human papillomaviruses (hpvs), designated p97 in the case of hpv-16, contains four characteristically aligned cis-responsive elements, namely one binding site for sp1, two for the viral e2 proteins, and the tata box. the sp1 binding site is needed to mediate activation of p97 by the remote epithelial-specific enhancer, and the two e2 binding sites contribute to a negative feedback-loop of viral gene expression. the sp1 consensus motif and the tata-box distal e2 bi ... | 1992 | 1311070 |
| cell transformation by animal papillomaviruses. | 1992 | 1311353 | |
| protective immunization against epstein-barr virus-induced disease in cottontop tamarins using the virus envelope glycoprotein gp340 produced from a bovine papillomavirus expression vector. | inoculation with epstein-barr virus (ebv) induces malignant lymphomas in the cottontop tamarin (saguinus oedipus oedipus). this provides an experimental animal model for assessing the efficacy of candidate ebv vaccines which are intended to reduce the incidence of human tumours associated with ebv infection. previous work has shown that experimental vaccines based on the major virus envelope glycoprotein gp340 prepared from the membranes of ebv-infected cells are effective in protecting cottonto ... | 1992 | 1311367 |
| increased calmodulin affects cell morphology and mrna levels of cytoskeletal protein genes. | we have previously described stable mouse c127 cell lines in which a cam mini-gene has been expressed in a bovine papilloma virus-based expression vector (rasmussen and means: embo j. 6:3961-3968, 1987). elevation of cam to levels five-fold higher than in control cells caused an acceleration in cell cycle progression by reducing the length of the g1 period. when these cell lines were originally isolated it was observed that cells in which cam levels were increased had a flattened morphology. in ... | 1992 | 1311642 |
| 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 |
| lack of immortalizing activity of a human papillomavirus type 16 variant dna with a mutation in the e2 gene isolated from normal human cervical keratinocytes. | the oncogenic potential of a human papillomavirus type 16 (hpv16) variant cloned from normal human cervical keratinocytes has been tested in vitro using primary rodent epithelial cells and human cervical keratinocytes. the hpv16 variant was able to extend the lifespan of, but failed to immortalize, human keratinocytes. it could however cooperate with an activated ras oncogene to transform primary rodent cells. radioimmunoprecipitation assays of the rodent cells showed that they expressed the e7 ... | 1992 | 1312701 |
| reconstitution of an episomal mouse aprt gene as a consequence of recombination. | when a functional murine adenine phosphoribosyltransferase (aprt) gene linked to bovine papilloma virus (bpv) dna is transfected into aprt- l cells, the cells are rendered aprt+ and the aprt gene persists as an episome. cotransfection with two bpv vectors, one containing the 5' half of the aprt gene and the other the 3' half of the gene, that share about 300 bp of common sequence in intron 2, produces aprt+ cells with functional aprt as an episome. southern blot analysis of low molecular weight ... | 1992 | 1313148 |
| a new retrovirus packaging cell for gene transfer constructed from amplified long terminal repeat-free chimeric proviral genes. | the retroviral gene transfer system is a powerful tool for somatic gene therapy. a retroviral stock with a high viral titer and lacking replication-competent virus (rcv) is desirable for this type of gene transfer. to fulfill these requirements, we made a new packaging cell line, designated ampli-gpe. to reduce the homology between proviral dna in the packaging cell and retroviral vector, the gag-pol and env genes of moloney murine leukemia virus were separated onto two different plasmids, pgp-k ... | 1992 | 1316479 |
| mechanism of action of the papillomavirus e2 repressor: repression in the absence of dna binding. | repression of papillomavirus e2-dependent gene expression was studied by using transient transfections into mouse embryo fibroblast cells. cotransfection of a gene corresponding to the naturally occurring repressor e2-tr along with the full-length e2 gene resulted in up to 98% repression of e2-dependent reporter gene expression. a series of e2 dna-binding domain mutants were transferred into the e2-tr form and characterized for their ability to repress e2-dependent transactivation. all mutants w ... | 1992 | 1316493 |
| vanadate enhances transformation of bovine papillomavirus dna-transfected c3h/10t1/2 cells. | bovine papillomavirus (bpv) dna-transfected c3h/10t1/2 cells respond to tumor promoters by enhanced production of transformed foci. vanadate, a suspected carcinogen, is a mitogen, generates active oxygen species and alters phosphorylation of proteins. we investigated whether vanadate would enhance transformation of bpv dna-transfected c3h/10t1/2 cells. transformed foci in bpv dna transfected c3h/10t1/2 cells exposed continuously to vanadate for 21 days increased in a dose-dependent manner to 50- ... | 1992 | 1317748 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| characterization of a stable eukaryotic cell line expressing the rous sarcoma virus integrase. | the rous sarcoma virus integration protein (in) is required for efficient integration of viral dna into the host genome. in was expressed in mouse c127 cells using a bovine papillomavirus vector. this system utilizes the mouse metallothionein promoter and the sv40 late polyadenylation signal for efficient expression of in. a stable cell line derived from a single hygromycin-resistant colony was characterized. the expression of in increased significantly upon zn2+ induction of the metallothionein ... | 1992 | 1322585 |
| multiple hpv infection: microanatomy by in situ hybridization and immunohistochemistry. | specific human papillomavirus (hpv) types have been shown to be associated with proliferative epithelial lesions with variable biological consequences in infected patients. simultaneous infection by more than one hpv type has been infrequently reported, and its clinical significance is unknown. we have examined four biopsies of cervical and vulvar tissue, each with evidence of infection by two different hpvs. using both in situ hybridization and immunohistochemical techniques, we determined the ... | 1992 | 1323102 |
| stable association between the bovine papillomavirus e5 transforming protein and activated platelet-derived growth factor receptor in transformed mouse cells. | the 44-amino acid e5 transforming protein of bovine papillomavirus is the shortest protein known to induce tumorigenic transformation of fibroblasts. we showed previously that expression of the e5 protein activates the cellular beta receptor for platelet-derived growth factor (pdgf) and proposed that the activated receptor transmits the transforming signal to the cell. here we use coimmunoprecipitation analysis to show that the e5 protein and the activated pdgf receptor exist in a stable complex ... | 1992 | 1323117 |
| 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 |
| 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 |
| 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 |
| synergism between bovine papillomavirus type 4 and the flavonoid quercetin in cell transformation in vitro. | bovine papillomavirus type 4 (bpv-4) morphologically transforms primary bovine cells in vitro only in the presence of an activated ras gene. the transformed cells are capable of anchorage-independent growth, but are not immortal and are incapable of inducing tumors in nude mice, suggesting that other events are needed to convert the cells to the fully transformed phenotype. we show here that treatment of the cells with a single dose of the flavonoid quercetin leads to full oncogenic transformati ... | 1992 | 1325710 |
| phylogenetic analysis of 48 papillomavirus types and 28 subtypes and variants: a showcase for the molecular evolution of dna viruses. | papillomaviruses are attractive models for studying the molecular evolution of dna viruses because of the large number of isolates that exhibit genomic diversity and host species and tissue specificity. to examine their relationship, we selected two amino acid sequences, one of 52 residues within the early gene e1 and the other of 44 residues within the late gene l1, which allowed insertion- and deletion-free alignment of all accessible papillomavirus sequences. we constructed phylogenetic trees ... | 1992 | 1326639 |
| 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 |
| 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 |
| 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 |
| 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 |
| separation of the transcriptional activation and replication functions of the bovine papillomavirus-1 e2 protein. | replication of bovine papillomavirus-1 (bpv-1) dna requires two viral gene products, the e1 protein and the full-length e2 protein. the 48 kda e2 protein is a site-specific dna-binding protein that binds to several sites which lie adjacent to the bpv-1 origin of replication. the 85 amino acid c-terminal domain contains the specific dna binding and dimerization properties of the protein. the approximately 200 amino acid n-terminal domain is crucial for transcriptional activation. both of these do ... | 1992 | 1327758 |
| 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 |
| 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 |
| analysis by polymerase chain reaction of the physical state of human papillomavirus type 16 dna in cervical preneoplastic and neoplastic lesions. | integration of human papillomavirus (hpv) dna into the host cell genome is believed to be essential for malignant progression. however unambiguous detection of the physical state of hpv is a difficult and time-consuming procedure. to resolve this issue a simple, rapid and highly sensitive technique of polymerase chain reaction (pcr) has been utilized for detecting the physical state of hpv-16 dna. investigations were carried out in 122 cervical specimens comprising the whole spectrum of cervical ... | 1992 | 1328489 |
| crystal structure at 1.7 a of the bovine papillomavirus-1 e2 dna-binding domain bound to its dna target. | the dominant transcriptional regulator of the papillomaviruses, e2, binds to its specific dna target through a previously unobserved dimeric antiparallel beta-barrel. the dna is severely but smoothly bent over the barrel by the interaction of successive major grooves with a pair of symmetrically disposed alpha-helices. the specific interface is an 'interwoven' network of interactions where the identifying base pairs of the target contact more than one amino-acid side chain and the discriminating ... | 1992 | 1328886 |
| 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 |
| search for bovine papilloma virus dna in bovine ocular squamous cell carcinomas (boscc) and boscc-derived cell lines. | although the cause of bovine ocular squamous cell carcinoma (boscc) is attributed to viruses in addition to cofactors (eg, uv light), to our knowledge, the final causative agent has not been described. bovine papilloma virus (bpv)-like particles were detected in approximately 33% of various putative precursor lesions of boscc. in contrast, it was reported that, using bpv-specific antibodies, it was not possible to detect viral antigens in boscc. fourteen established boscc and 9 boscc-derived cel ... | 1992 | 1329585 |
| 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 |
| random-choice replication of extrachromosomal bovine papillomavirus (bpv) molecules in heterogeneous, clonally derived bpv-infected cell lines. | using fluorescence in situ hybridization and southern blot analysis, we show that three clonally derived cell lines transformed with bovine papillomavirus (bpv), including id13, the cell line commonly employed for bpv replication studies, are heterogeneous populations having extensive cell-to-cell variation in both the distribution and amount of bpv dna. different subclones of id13 were found to differ in the form and amount of bpv dna they contain. most subclones showed no detectable bpv sequen ... | 1992 | 1331505 |
| a constitutive enhancer in the bovine papillomavirus upstream regulatory region shares genetic elements with the viral p1 promoter. | the bovine papillomavirus upstream regulatory region represents a common element in the regulation of transcription from the five early viral promoters. we have determined the sequences required for transcription from the viral p1 promoter, which is located at the 5' end of the upstream regulatory region. in vitro transcription from p1 requires a 123-bp fragment (nucleotides 7153 to 7275; -33 to +90) consisting of an upstream tata-like sequence as well as an unidentified protein which binds to s ... | 1992 | 1331522 |
| glucocorticoid modulation of transformed cell proliferation is oncogene specific and correlates with effects on c-myc levels. | in the presence of the glucocorticoid hormone dexamethasone, bovine papillomavirus-1 (bpv-1)-transformed c127 mouse fibroblasts assume a flattened morphology and reach a saturation density of only 50% of that attained without hormone. this phenotypic reversion of transformation is dependent on the continued presence of dexamethasone and occurs with concentrations as low as 1 nm. dexamethasone also suppresses the growth of the parental c127 cells as well as that of cells transformed by polyoma mi ... | 1992 | 1331773 |
| purification and characterization of epstein-barr virus gp340/220 produced by a bovine papillomavirus virus expression vector system. | our initial results with a bovine papilloma virus (bpv) vector expression system indicated that we could produce significant amounts of epstein-barr virus (ebv) gp340/220 in the supernatant of a mouse fibroblast cell line. we have now extended these findings to show that the truncated version of gp340/220, where the membrane anchor sequence is deleted, is produced even after extended passage of the cells, at a level of approximately 1 mg/4 x 10(8) cells. a simple purification protocol using seph ... | 1992 | 1332270 |
| 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 |
| human papillomavirus type 16 expresses a variety of alternatively spliced mrnas putatively encoding the e2 protein. | the full-length e2 protein of human papillomavirus type 16 is believed to act as a trans-repressor of the viral p97 promoter. previous reports have provided evidence that transcripts with the potential to encode the e2 protein contain the 880/2708 splice junction. we have further analyzed the structure of the e2-encoding transcripts. employing the rna polymerase chain reaction (pcr) technique and analyses of the rna pcr products by southern blot hybridization and dna sequencing, we revealed the ... | 1992 | 1333130 |
| 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 |
| association of bovine papillomavirus type 2 and bracken fern with bladder cancer in cattle. | the bladder cancer syndrome that often accompanies chronic enzootic hematuria in cattle grazing on pastures infested by bracken fern has been experimentally reproduced in animals fed a diet of bracken. the experimentally induced tumors were histologically and pathologically indistinguishable from the naturally occurring ones and comprised two main types: (a) carcinoma of the urothelium identical to that seen in humans; and (b) hemangioendotheliomas of the subjacent capillaries. often the two typ ... | 1992 | 1333885 |
| 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 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 |
| 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 |
| acquisition of interleukin-3 independence in fdc-p2 cells after transfection with the activated c-h-ras gene using a bovine papillomavirus-based plasmid vector. | since the ras family of proto-oncogenes is supposed to be involved in leukemogenesis by point-mutational activation, we studied the effect of the activated ras gene on the growth of a murine interleukin-3 (il-3)-dependent cell line, fdc-p2. the human activated c-h-ras gene was transfected into fdc-p2 cells by electroporation using a high-level expression vector, bmghph, which contains a partial dna sequence from bovine papillomavirus (bpv) and a hygromycin b (hmb)-resistant gene as a selectable ... | 1992 | 1334732 |
| does cruciform dna provide a recognition signal for dna-topoisomerase ii? | topoisomerase ii displays higher affinity for supercoiled dna compared to the same relaxed dna. moreover, cruciform structures are formed in topologically constrained dna. here we report that, using s1 nuclease experiments on supercoiled dna, hairpin structures are located close to numerous topoisomerase ii cleavage sites on the bpv i genome. therefore, dna secondary structure may play a role in the recognition mechanism of dna by topoisomerase ii. | 1992 | 1335757 |
| interaction with the nuclear matrix of a chimeric construct containing a replication origin and a transcription unit. | we have studied the interaction of a chimeric construct containing an origin of replication (from bovine papilloma virus) and a hormonally regulated transcription unit (long terminal repeat from the mouse mammary tumor virus, driving the v-ha-ras gene) with the nuclear scaffold and matrix from mouse fibroblasts. we used two experimental approaches because the nuclear matrix protein composition depends largely on the isolation conditions, making its definition mostly operational. in situ studies ... | 1992 | 1336395 |
| inducible expression bovine papillomavirus shuttle vectors containing ferritin translational regulatory elements. | the combination of transcriptional and translational control elements in an inducible expression vector suitable for use in stably transformed cell lines was explored. to this end, ferritin translational control elements have been inserted downstream from a mouse metallothionein (mmt-i) transcriptional promoter (pmmt-i), and upstream from various reporter protein-encoding open reading frames (orfs), all carried on a bovine papillomavirus shuttle vector. protocols which stimulate transcription (w ... | 1992 | 1336755 |
| the efficiency and timing of plasmid dna replication in xenopus eggs: correlations to the extent of prior chromatin assembly. | injection of the circular plasmid fv1 (derived from type i bovine papilloma virus) into xenopus eggs before the start of the first cell cycle dramatically increases the efficiency of plasmid replication once eggs are chemically activated. we call this the preloading effect and report kinetic and quantitative characterization of this phenomenon here. the timing and the amount of fv1 synthesis were measured by both brdutp density labelling and an optimized method of selective enzymatic digestion o ... | 1992 | 1336780 |
| comparative analysis of inositol phospholipid metabolism in viral and chemical transformation of mammalian cells. | 1. inositol phospholipid metabolites were measured from virally and chemically transformed cells. 2. increased levels of pip and pip2 were observed from both transformed cell lines as compared with controls. 3. intracellular levels of ip3 were also increased approximately three folds in bpv-1 infected id 13 cells and in 3-mc transformed nih 3t3 cells. 4. the results suggest that phosphorylation of phosphatidylinositols and enhanced generation of ip3 second messenger molecules are the common sign ... | 1992 | 1360364 |
| chemical modifications to improve uptake and bioavailability of antisense oligonucleotides. | 1992 | 1364095 | |
| 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 |
| levels of immunoglobulin g antibodies against defined epitopes of the l1 and l2 capsid proteins of human papillomavirus type 6 are elevated in men with a history of condylomata acuminata. | sera from 159 men attending the sexually transmitted disease clinic at karolinska hospital, stockholm, sweden, were analyzed for the presence of immunoglobulin a (iga) and igg antibodies to a panel of synthetic peptides derived from the e2, l1, and l2 regions of the human papillomavirus types 1 (hpv 1), 6, 8, 11, 16, 18, 31, and 33. the study subjects were divided into three groups: (i) asymptomatic men with no history of genital warts who served as controls, (ii) men with visible condylomata, a ... | 1992 | 1378454 |
| 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 |
| transcription factors junb and c-jun are selectively up-regulated and functionally implicated in fibrosarcoma development. | bovine papillomavirus transgenic mice develop skin tumors arising from dermal fibroblasts in a process comprised of three distinctive stages: mild and aggressive fibromatoses, and fibrosarcoma. in both tissue biopsies and derivative cell lines, the proto-oncogenes junb and c-jun are induced in the latter two stages, in contrast to jund and fos. fibrosarcoma cell lines have increased ap-1 dna-binding activity. overexpression of junb or c-jun by transfection into the mild fibromatosis stage elicit ... | 1992 | 1459456 |
| analysis of the influences of the e5 transforming protein on kinetic parameters of epidermal growth factor binding and metabolism. | the e5 protein of the bovine papillomavirus induces cellular transformation when transfected into nih 3t3 cells, and the extent of focal transformation is enhanced by cotransfection with the epidermal growth factor (egf) receptor (martin et al., cell 59:21-32, 1989). to determine whether e5 affects egf:receptor interactions we analyzed the kinetics of 125i-egf processing using a mathematical model that enabled us to evaluate rate constants for ligand association (ka), dissociation (kd), internal ... | 1992 | 1639860 |