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epithelial specific transcriptional regulation of the bovine papillomavirus 4 promoter by e2.bovine papillomavirus 4 (bpv-4) is a mucosal epitheliotropic papillomavirus. it encodes a transcriptional regulator, e2, which acts on the bpv-4 transcriptional control region (the long control region or lcr) to regulate transcription. the distribution of e2 binding sites within the lcr of bpv-4 is identical to that of the human papillomaviruses hpv-16 and hpv-18, indicating that the mechanism of transcriptional control by e2 of mucosal epitheliotropic papillomaviruses is conserved. in this stud ...19989519828
segregation of viral plasmids depends on tethering to chromosomes and is regulated by phosphorylation.eukaryotic viruses can maintain latency in dividing cells as extrachromosomal nuclear plasmids. segregation and nuclear retention of dna is, therefore, a key issue in retaining copy number. the e2 enhancer protein of the papillomaviruses is required for viral dna replication and transcription. viral mutants that prevent phosphorylation of the bovine papillomavirus type 1 (bpv) e2 protein are transformation-defective, despite normal viral gene expression and replication function. cell colonies ha ...19989539738
transactivation-competent bovine papillomavirus e2 protein is specifically required for efficient repression of human papillomavirus oncogene expression and for acute growth inhibition of cervical carcinoma cell lines.the papillomavirus e2 proteins can function as sequence-specific transactivators or transrepressors of transcription and as cofactors in viral dna replication. we previously demonstrated that acute expression of the bovine papillomavirus type 1 (bpv1) e2 protein in hela and ht-3 cervical carcinoma cell lines greatly reduced cellular proliferation by imposing a specific g1/s phase growth arrest. in this report, we analyzed the effects of a panel of point mutations in the bpv1 e2 protein to identi ...19989557678
dna packaging by l1 and l2 capsid proteins of bovine papillomavirus type 1.encapsidation of circular dna by papillomavirus capsid protein was investigated in cos-1 cells. plasmids carrying both an sv40 origin of replication (ori) and an e. coli ori were introduced into cos-1 cells by dna transfection pv capsid proteins were supplied in trans by recombinant vaccinia viruses. pseudovirions were purified from infected cells and their packaged dna was extracted and used to transform e. coli as an indication of packaging efficacy. vlps assembled from bpv-1 l1 alone packaged ...19989568045
significant behavioral recovery in parkinson's disease model by direct intracerebral gene transfer using continuous injection of a plasmid dna-liposome complex.as an alternative to virus-mediated gene transfer, we previously demonstrated a simple, safe, and efficient transfer of foreign gene into the central nervous system using continuous injection of a plasmid dna-cationic liposome complex. to explore whether this approach can be applied to the treatment of certain neurological disorders, we used an experimental model of parkinson's disease (pd) in the present study. following continuous injection for 7 days, tyrosine hydroxylase (th) and aromatic l- ...19989607420
selective ablation of human t-cell lymphotropic virus type 1 p12i reduces viral infectivity in vivo.human t-cell lymphotropic virus type 1 (htlv-1) is the etiologic agent of adult t-cell leukemia and htlv-1-associated myelopathy. novel, yet conserved rna transcripts encoded from open reading frames (orfs) i and ii of the viral px region are expressed both in vitro and in infected individuals. the orf i mrna encodes the protein p12(i), which has been shown to localize to cellular endomembranes, cooperate with bovine papillomavirus e5 in transformation, as well as bind to the il-2 receptor beta ...19989616168
virocrine transformation: the intersection between viral transforming proteins and cellular signal transduction pathways.this review describes a mechanism of viral transformation involving activation of cellular signaling pathways. we focus on four viral oncoproteins: the e5 protein of bovine papillomavirus, which activates the platelet-derived growth factor beta receptor; gp55 of spleen focus forming virus, which activates the erythropoietin receptor; polyoma virus middle t antigen, which resembles an activated receptor tyrosine kinase; and lmp-1 of epstein-barr virus, which mimics an activated tumor necrosis fac ...19989891803
the papillomavirus minor capsid protein, l2, induces localization of the major capsid protein, l1, and the viral transcription/replication protein, e2, to pml oncogenic domains.we have used immunofluorescent staining and confocal microscopy to examine the subcellular localization of structural and nonstructural bovine papillomavirus (bpv) proteins in cultured cells that produce infectious virions. when expressed separately, l1, the major capsid protein, showed a diffuse nuclear distribution while l2, the minor capsid protein, was found to localize to punctate nuclear regions identified as promonocytic leukemia protein (pml) oncogenic domains (pods). coexpression of l1 ...19989420209
interaction of the bovine papillomavirus e6 protein with the clathrin adaptor complex ap-1.the e6 gene of the bovine papillomavirus type 1 (bpv-1) is expressed in fibropapillomas caused by bpv-1 and in tissue culture cells transformed by bpv-1. it encodes one of the two major oncoproteins of bpv-1. in this study, we demonstrate an interaction between the bpv-1 e6 protein and ap-1, the tgn (trans-golgi network)-specific clathrin adaptor complex. ap-1 is a four-subunit protein complex required for clathrin-mediated cellular transport from the tgn. the ap-1/e6 interaction was observed in ...19989420248
functional interaction of the bovine papillomavirus e2 transactivation domain with tfiib.induction of gene expression by the papillomavirus e2 protein requires its approximately 220-amino-acid amino-terminal transactivation domain (tad) to interact with cellular factors that lead to formation of an activated rna polymerase complex. these interaction partners have yet to be identified and characterized. the e2 protein localizes the transcription complex to the target promoter through its carboxy-terminal sequence-specific dna binding domain. this domain has been reported to bind the ...19989444994
polyomavirus large t can support dna replication in human cells.human cells are generally thought to be nonpermissive for polyomavirus (py) dna replication. using transient transfection, we show that py large t-antigen (lt) was able to support replication of a py origin-containing plasmid in two human cell lines. replication supported by lt in human cells was specific for the py origin and required its enhancer sequences, as well as the previously reported critical phosphorylation sites within lt. py replication efficiency was comparable to that of papilloma ...19989448688
inhibition/stimulation of bovine papillomavirus by adeno-associated virus is time as well as multiplicity dependent.infection by adeno-associated virus (aav) is associated with lower cervical cancer rates. we have been investigating the hypothesis that aav interacts with and inhibits the role of human papillomaviruses (hpv) in cervical cancer. we have been studying the response of bovine papillomavirus type 1 (bpv) oncogenic transformation and dna replication to aav as a prototype system. the aav rep 78 gene product is responsible for this inhibition. here, it is demonstrated that in two assay systems, focus ...19989705917
papillomavirus virus-like particles can deliver defined ctl epitopes to the mhc class i pathway.to evaluate an antigen delivery system in which exogenous antigen can target the major histocompatibility complex (mhc) class i pathway, a single human papillomavirus (hpv) 16 e7 cytotoxic t lymphocyte (ctl) epitope and a single hiv gp160 ctl epitope were separately fused to the c-terminus of bovine papillomavirus 1 (bpv1) l1 sequence to form hybrid bpv1l1 vlps. mice immunized with these hybrid vlps mounted strong ctl responses against the relevant target cells in the absence of any adjuvants. i ...19989448699
association of bovine papillomavirus type 1 e6 oncoprotein with the focal adhesion protein paxillin through a conserved protein interaction motif.we have found that the e6 oncoprotein of bovine papillomavirus type 1 (be6) as well as the e6 protein of the cancer associated hpv-16 (16e6) interact with the focal adhesion protein paxillin. mutational analysis of paxillin revealed that be6 binds paxillin through small protein interaction motifs called ld motifs that have been previously identified as important in regulating association of paxillin with vinculin and focal adhesion kinase (fak), and that be6 can interact with at least two separa ...19989467941
human fibroblasts expressing the human papillomavirus e6 gene are deficient in global genomic nucleotide excision repair and sensitive to ultraviolet irradiation.we investigated the role of wild-type p53 activity in modulating nucleotide excision repair after uv irradiation in normal and p53-deficient primary human fibroblasts created by expression of the human papillomavirus 16 e6 gene. compared with parental cells, the e6-expressing fibroblasts were deficient in global genomic repair of both uv-induced cyclobutane pyrimidine dimers and 6-4 photoproducts but exhibited normal transcription-coupled repair. the e6-expressing cells were also more sensitive ...19989485006
calcium is required in reassembly of bovine papillomavirus in vitro.papillomaviruses are small dna viruses which infect and induce benign warts and sometimes malignant tumours in the epithelium of the skin or mucosa. the viruses do not replicate in conventional tissue culture systems and little is known about the requirements for virus assembly. we investigated the effect of ethylene glycol-bis(aminoethyl ether)-tetraacetic acid (egta) and dithiothreitol (dtt) treatment on the stability of bovine papillomavirus type 1 (bpv-1) particles in vitro. removal of calci ...19989603328
p53 protein is a suppressor of papillomavirus dna amplificational replication.p53 protein was able to block human and bovine papillomavirus dna amplificational replication while not interfering with epstein-barr virus orip once-per-cell cycle replication. oligomerization, intact dna-binding, replication protein a-binding, and proline-rich domains of the p53 protein were essential for efficient inhibition, while the n-terminal transcriptional activation and c-terminal regulatory domains were dispensable for the suppressor activity of the p53 protein. the inhibition of repl ...19989658131
transient viral dna replication and repression of viral transcription are supported by the c-terminal domain of the bovine papillomavirus type 1 e1 protein.the bovine papillomavirus type 1 e1 protein is important for viral dna replication and transcriptional repression. it has been proposed that the full-length e1 protein consists of a small n-terminal and a larger c-terminal domain. in this study, it is shown that an e1 polypeptide containing residues 132 to 605 (which represents the c-terminal domain) is able to support transient viral dna replication, although at a level lower than that supported by the wild-type protein. this domain can also re ...19989420289
bovine papillomavirus type 1 genomes and the e2 transactivator protein are closely associated with mitotic chromatin.the bovine papillomavirus type 1 e2 transactivator protein is required for viral transcriptional regulation and dna replication and may be important for long-term episomal maintenance of viral genomes within replicating cells (m. piirsoo, e. ustav, t. mandel, a. stenlund, and m. ustav, embo j. 15:1-11, 1996). we have evidence that, in contrast to most other transcriptional transactivators, the e2 transactivator protein is associated with mitotic chromosomes in dividing cells. the shorter e2-tr a ...19989499063
an embryonic demethylation mechanism involving binding of transcription factors to replicating dna.in vertebrates, transcriptionally active promoters are undermethylated. since the transcription factor sp1, and more recently nf-kappab, have been implicated in the demethylation process, we examined the effect of transcription factors on demethylation by injecting in vitro methylated plasmid dna into xenopus fertilized eggs. we found that various transactivation domains, including a strong acidic activation domain from the viral protein vp16, can enhance demethylation of a promoter region when ...19989482741
origin dna-binding proteins.the first step in dna replication involves the recognition of origin dna sequences by origin-binding proteins. the three-dimensional structures of three different origin dna-binding proteins have recently been solved. these proteins form a structural class distinct from other dna-binding proteins. one of the origin-binding proteins, epstein-barr virus nuclear antigen 1, most likely has two modes of dna binding; the sequential use of these modes may be important for the initiation of dna replicat ...19989519296
characterization of the dna-binding domain of the bovine papillomavirus replication initiator e1.the bovine papillomavirus replication initiator protein e1 is an origin of replication (ori)-binding protein absolutely required for viral dna replication. in the presence of the viral transcription factor e2, e1 binds to the ori and initiates dna replication. to understand how the e1 initiator recognizes the ori and how e2 assists in this process, we have expressed and purified a 166-amino-acid fragment which corresponds to the minimal e1 dna-binding domain (dbd). dna binding studies using this ...19989525573
stability without a centromere. 19989539691
a broad-spectrum microbicide with virucidal activity against sexually transmitted viruses.sodium dodecyl sulfate (sds), an alkyl sulfate surfactant derived from an organic alcohol, possesses surfactant properties but also denatures and unfolds both monomeric and subunit proteins. in preliminary experiments, we demonstrated that sds is a potent inactivator of herpes simplex virus type 2 and human immunodeficiency virus type 1 at concentrations comparable to those used for the surfactant nonoxynol-9. we hypothesized that sds might be capable of denaturing the capsid proteins of nonenve ...19999925525
detection of human papillomavirus type 10 dna in eccrine syringofibroadenomatosis occurring in clouston's syndrome.syringofibroadenomatosis is often associated with an underlying condition such as diabetes mellitus or hidrotic ectodermal dysplasia. by reason of these associations, a reactive or hamartomatous cause is suspected. we report a case of a 71-year-old woman with clouston's syndrome in whom progressive multiple palmoplantar syringofibroadenomas developed over a 10-year period. the syringofibroadenomas formed flat-topped papules simulating verruca plana; the widespread distribution and chronic progre ...199910025758
the transmembrane domain of the e5 oncoprotein contains functionally discrete helical faces.the e5 protein of bovine papillomavirus is a 44-amino acid, golgi-resident, type ii transmembrane protein that efficiently transforms immortalized mouse fibroblasts. the transmembrane (tm) domain of e5 is not only critical for biological activity, it also regulates interactions with cellular targets including the platelet derived growth factor receptor (pdgf-r) and the 16-kda subunit of the vacuolar proton atpase (v-atpase). in order to define the specific tm amino acids essential for e5 biologi ...199910187811
long-term episomal maintenance of bovine papillomavirus type 1 plasmids is determined by attachment to host chromosomes, which is mediated by the viral e2 protein and its binding sites.papillomavirus genomes are stably maintained as extrachromosomal nuclear plasmids in dividing host cells. to address the mechanisms responsible for stable maintenance of virus, we examined nuclear compartmentalization of plasmids containing the full-length upstream regulatory region (urr) from the bovine papillomavirus type 1 (bpv1) genome. we found that these plasmids are tightly associated with the nuclear chromatin both in the stable cell lines that maintain episomal copies of the plasmids an ...199910196338
persistent expression of foreign genes in cultured hepatocytes: expression vectors.we have optimized a liposome-based transfection method that mediated highly efficient stable expression of foreign genes in hepatocytes. moreover, we have observed that the metallothionein 1 promoter in the bovine papilloma virus-based expression vector drove the highest expression of foreign genes in hepatocytes as compared with the cytomegalovirus and the human polypeptide chain elongation factor 1alpha (ef-1alpha) promoters in the pcdna 3-based expression vector. the cytomegalovirus promoter ...199910196472
interactions of the papovavirus dna replication initiator proteins, bovine papillomavirus type 1 e1 and simian virus 40 large t antigen, with human replication protein a.papovaviruses utilize predominantly cellular dna replication proteins to replicate their own viral genomes. to appropriate the cellular dna replication machinery, simian virus 40 (sv40) large t antigen (tag) binds to three different cellular replication proteins, the dna polymerase alpha-primase complex, the replication protein a (rpa) complex, and topoisomerase i. the functionally similar papillomavirus e1 protein has also been shown to bind to the dna polymerase alpha-primase complex. enzyme-l ...199910233951
bovine papillomaviral gene expression in equine sarcoid tumours.the sarcoid is a benign locally invasive dermal fibroblastic lesion, commonly affecting horses and donkeys. the aetiology of the equine sarcoid is equivocal. bovine papillomaviral (bpv) dna (type 1/2) is frequently demonstrable in equine sarcoid tumour biopsies. however, the exact role of the virus in the disease process and its contribution to the phenotypic differences in sarcoids is not known. it was sought to assess the transcriptional activity of bpv-1 found in sarcoid tissues. of 20 tumour ...199910475087
an enhanced epithelial response of a papillomavirus promoter to transcriptional activators.mucosal epitheliotropic papillomaviruses have a similar long control region (lcr) organization: a promoter region, an enhancer region, and a highly conserved distribution of e2 dna binding sites. the enhancer of these viruses is epithelial-specific, as it fails to activate transcription from heterologous promoters in nonepithelial cell types (gloss, b., bernard, h. u., seedorf, k., and klock, g. (1987) embo j. 6, 3735-3743; morgan, i. m., grindlay, g. j., and campo, m. s. (1999) j. gen. virol. 8 ...199910488130
papillomavirus e2 induces p53-independent apoptosis in hela cells.we have previously shown that expression of the papillomavirus e2 protein in hela cells induces p53 accumulation and causes both cell cycle arrest and apoptosis. in contrast to growth arrest, onset of apoptosis was not correlated with an increase of p53 transcriptional activity. in the present study, we conducted biochemical and genetic experiments in order to determine whether e2-induced apoptosis was independent of p53 induction. we showed that e2 did not alter the transcription of bax, a know ...199910467398
protein-sulfenic acids: diverse roles for an unlikely player in enzyme catalysis and redox regulation.while it has been known for more than 20 years that unusually stable cysteine-sulfenic acid (cys-soh) derivatives can be introduced in selected proteins by mild oxidation, only recently have chemical and crystallographic evidence for functional cys-soh been presented with native proteins such as nadh peroxidase and nadh oxidase, nitrile hydratase, and the horf6 and ahpc peroxiredoxins. in addition, cys-soh forms of protein tyrosine phosphatases and glutathione reductase have been suggested to pl ...199910569923
two distinct regions of the bpv1 e1 replication protein interact with the activation domain of e2.papillomavirus e1 and e2 proteins co-operation in viral dna replication is mediated by protein-protein interactions that lead to formation of an e1-e2 complex. to identify the domains involved, portions of the two proteins were expressed as fusions to the dna-binding protein lexa or the transactivation domain of vp16 and analyzed by the yeast two-hybrid system. the c-terminal 266 amino acids of bpv1 e1 (e1c266) interacted strongly with e2 in the yeast system and in a mammalian two-hybrid assay. ...199910581387
structural correlates for enhanced stability in the e2 dna-binding domain from bovine papillomavirus.papillomaviral e2 proteins participate in viral dna replication and transcriptional regulation. we have solved the solution structure of the dna-binding domain of the e2 protein from bovine papillomavirus (bpv-1). the structure calculation used 2222 distance and 158 dihedral angle restraints for the homodimer (202 residues in total), which were derived from homonuclear and heteronuclear multidimensional nuclear magnetic resonance (nmr) spectroscopic data. the root-mean-square deviation for struc ...199910587434
a structural model for the rola protein and its interaction with dna.the study of the plant oncogene rola has been hampered by a lack of structural information. here we show that, despite a lack of significant sequence similarity to proteins of known structure, the rola sequence adopts a known fold; that of the papillomavirus e2 dna-binding domain. this fold is reliably identified by modern threading programs, which consider predicted secondary structure, but not by others. although the rola sequence is only around 16% identical to those of the available template ...199910651283
the bovine papillomavirus e5 protein requires a juxtamembrane negative charge for activation of the platelet-derived growth factor beta receptor and transformation of c127 cells.the bovine papillomavirus e5 gene encodes a 44-amino-acid, homodimeric transmembrane protein that is the smallest known transforming protein. the e5 protein transforms cultured fibroblasts by forming a stable complex with the endogenous platelet-derived growth factor (pdgf) beta receptor through transmembrane and juxtamembrane interactions, leading to sustained receptor activation. aspartic acid 33 in the extracellular juxtamembrane region of the e5 protein is important for cell transformation a ...199910074180
induction of autoantibodies to mouse ccr5 with recombinant papillomavirus particles.the vertebrate immune system has evolved to respond vigorously to microbial infection but to ignore self-antigens. evidence has emerged that b cell responses to viruses are initiated by immune recognition of ordered arrays of antigen on the viral surface. to test whether autoantibodies against a self-antigen can be induced by placing it in a context that mimics the ordered surface of a viral particle, a peptide representing an extracellular loop of the mouse chemokine receptor ccr5 was incorpora ...199910051649
a mutational analysis of the transforming functions of the e8 protein of bovine papillomavirus type 4.the e8 protein of bpv-4 contributes to transformation of primary bovine cells (palfs) by inducing anchorage-independent growth and by down-regulating gap junction intercellular communication, likely due to its binding to 16k ductin. we show here that, in addition, e8 confers on palf cells the ability to grow in low serum and to escape from contact inhibition (focus formation). e8 also transactivates an exogenous human cyclin a gene promoter, suggesting that overexpression of cyclin a is responsi ...199910069964
binding of the human papillomavirus type 16 p97 promoter by the adeno-associated virus rep78 major regulatory protein correlates with inhibition.human papillomavirus type 16 (hpv-16) infection is positively associated with cervical cancer, whereas adeno-associated virus (aav) infection is negatively associated with this same cancer. in earlier studies these two virus types have been shown to directly interact, with aav inhibiting or enhancing papillomavirus functions depending upon the specific circumstances. one defined interaction between these two viruses is the ability of the aav rep78 major regulatory protein to inhibit gene express ...199910531369
papillomavirus capsid protein expression level depends on the match between codon usage and trna availability.translation of mrna encoding the l1 and l2 capsid proteins of papillomavirus (pv) is restricted in vivo to differentiated epithelial cells, although transcription of the l1 and l2 late genes occurs more widely. the codon composition of pv late genes is quite different from that of most mammalian genes. to test the possibility that pv late gene codon composition determines the efficiency of pv late gene expression in some cell types, synthetic bovine papillomavirus type 1 (bpv1) late genes were c ...199910233959
role of the atp-binding domain of the human papillomavirus type 11 e1 helicase in e2-dependent binding to the origin.replication of the genome of human papillomaviruses (hpv) is initiated by the recruitment of the viral e1 helicase to the origin of dna replication by the viral e2 protein, which binds specifically to the origin. we determined, for hpv type 11 (hpv-11), that the c-terminal 296 amino acids of e1 are sufficient for interaction with the transactivation domain of e2 in the yeast two-hybrid system and in vitro. this region of e1 encompasses the atp-binding domain. here we have examined the role of th ...199910364274
nucleotides 1506-1625 of bovine papillomavirus type 1 genome can enhance dna packaging by l1/l2 capsids.we have previously described a dna-packaging assay using bovine papillomavirus type 1 (bpv-1) virus-like particles (vlps) and have identified a region of the bpv genome that assists in packaging. in this study, we identify a specific bpv sequence involved in dna packaging by bpv-1 vlps. in the initial screening of bpv-1 genomic sequences essential for dna packaging, we observed that a plasmid with deletions between nucleotides (nt) 948 and 2113 failed to be packaged into bpv-1 vlps. however, pla ...199910364505
high precision solution structure of the c-terminal kh domain of heterogeneous nuclear ribonucleoprotein k, a c-myc transcription factor.among it's many reported functions, heterogeneous nuclear ribonucleoprotein (hnrnp) k is a transcription factor for the c- myc gene, a proto-oncogene critical for the regulation of cell growth and differentiation. we have determined the solution structure of the gly26-->arg mutant of the c-terminal k-homology (kh) domain of hnrnp k by nmr spectroscopy. this is the first structure investigation of hnrnp k. backbone residual dipolar couplings, which provide information that is fundamentally differ ...199910369774
identification of survival motor neuron as a transcriptional activator-binding protein.spinal muscular atrophy (sma) is an inherited neuro-muscular disease characterized by specific degeneration of spinal cord anterior horn cells and subsequent muscle atrophy. survival motor neuron ( smn ), located on chromosome 5q13, is the sma-determining gene. in the nucleus, smn is present in large foci called gems, the function of which is not yet known, while cytoplasmic smn has been implicated in snrnp biogenesis. in sma patients, smn protein levels and the number of gems generally correlat ...199910369867
bovine papillomavirus e2 protein activates a complex growth-inhibitory program in p53-negative ht-3 cervical carcinoma cells that includes repression of cyclin a and cdc25a phosphatase genes and accumulation of hypophosphorylated retinoblastoma protein.the bovine papillomavirus e2 protein can inhibit the proliferation of ht-3 cells, a p53-negative cervical carcinoma cell line containing integrated human papillomavirus type 30 dna. here, we analyzed ht-3 cells to explore the mechanism of p53-independent e2-mediated growth inhibition. expression of the e2 protein repressed expression of the endogenous human papillomavirus type 30 e6/e7 genes. this was accompanied by hypophosphorylation and increased accumulation of p105rb and repression of e2f1 ...199910392903
nucleotide sequence and characterization of human papillomavirus type 83, a novel genital papillomavirus.studies of human papillomaviruses (hpv) are hampered by the lack of a conventional culture system, because hpv completes its life cycle only in fully differentiated human tissue. to overcome this obstacle, the athymic mouse xenograft system has been used to study the pathogenesis of a limited number of hpv types. we recently reported the propagation of a novel hpv type in the mouse xenograft system and the cloning of its genome. consensus primer pcr had previously identified this virus as mm7, l ...199910405368
many different papillomaviruses have low transcriptional activity in spite of strong epithelial specific enhancers.transcription of the e6-e7 genes of human papillomavirus type 11 (hpv-11), hpv-16 and hpv-18 is specific to epithelial cells. this mechanism originates from synergism between different transcription factors such as ap-1, nfi and sp1, which occur in many different cell types, but whose activity is biased in favour of epithelial cells. in this study, the transcriptional regulation of 14 different papillomavirus types in the absence of the viral e2 transcription factor was compared. genital hpv typ ...199910423140
human papillomavirus dna replication compartments in a transient dna replication system.many dna viruses replicate their genomes at nuclear foci in infected cells. using indirect immunofluorescence in combination with fluorescence in situ hybridization, we colocalized the human papillomavirus (hpv) replicating proteins e1 and e2 and the replicating origin-containing plasmid to nuclear foci in transiently transfected cells. the host replication protein a (rp-a) was also colocalized to these foci. these nuclear structures were identified as active sites of viral dna synthesis by brom ...19999882301
biochemical and electron microscopic image analysis of the hexameric e1 helicase.dna replication initiator proteins bind site specifically to origin sites and in most cases participate in the early steps of unwinding the duplex. the papillomavirus preinitiation complex that assembles on the origin of replication is composed of proteins e1 and the activator protein e2. e2 is an ancillary factor that increases the affinity of e1 for the ori site through cooperative binding. here we show that duplex dna affects e1 (in the absence of e2) to assemble into an active hexameric stru ...19999933649
the bovine papillomavirus type 4 long control region contains an epithelial specific enhancer.bovine papillomavirus type 4 (bpv-4) is a mucosal epitheliotropic virus that is a causative agent in alimentary carcinoma of cattle. the long control region (lcr) of this virus controls expression of the transforming proteins, e8 and e7. deletion mutants of the lcr were prepared and assayed for their ability to activate transcription from the lcr promoter in primary bovine palate keratinocytes (the natural target cell for bpv-4) and fibroblasts. the lcr was at least an order of magnitude more ac ...19999934679
the bovine papillomavirus type 1 e6 oncoprotein sensitizes cells to tumor necrosis factor alpha-induced apoptosis.expression of viral proteins may result in susceptibility of cells to the cytotoxic effect of tumor necrosis factor alpha (tnf). while murine c127 cells containing the bovine papillomavirus type 1 (bpv-1) genome were reported to exhibit increased tnf sensitivity, the gene(s) responsible was not identified. the bpv-1 e6 oncoprotein induces tumorigenic transformation of murine c127 cells and stimulates transcription when targeted to a promoter. bpv-1 e6 was introduced into c127 cells (pbe6) by ret ...19999989810
a method for efficient extraction of bovine papilloma virus-based minichromosomes that preserves native chromatin structure.aiming to create an adequate model for investigation of the molecular mechanisms involved in transcriptional regulation by steroid hormones, a number of cell lines carrying bovine papilloma virus (bpv) based constructs containing the mouse mammary tumor virus long terminal repeat (ltr) were established (ostrowski et al., mol. cell. biol. 3, 2945-2957, 1983). however, all our attempts to extract from the cells such minichromosomes as nucleoprotein complexes using a method previously described (os ...199910619601
function of a bovine papillomavirus type 1 exonic splicing suppressor requires a suboptimal upstream 3' splice site.alternative splicing is an important mechanism for the regulation of bovine papillomavirus type 1 (bpv-1) gene expression during the virus life cycle. previous studies in our laboratory have identified two purine-rich exonic splicing enhancers (eses), se1 and se2, located between two alternative 3' splice sites at nucleotide (nt) 3225 and nt 3605. further analysis of bpv-1 late-pre-mrna splicing in vitro revealed a 48-nt pyrimidine-rich region immediately downstream of se1 that inhibits utilizat ...19999847303
effect of bovine papillomavirus e2 protein-specific monoclonal antibodies on papillomavirus dna replication.the bovine papillomavirus type 1 (bpv-1) e2 protein is the master regulator of papillomavirus replication and transcription. we have raised a panel of monoclonal antibodies (mabs) against the bpv-1 e2 protein and used them to probe the structure and function of the protein. five mabs reacted with linear epitopes, and four mabs recognized conformation-dependent epitopes which mapped within the c-terminal dna-binding and dimerization domain. mab 1e2 was able to recognize the replication- and trans ...199910233926
adeno-associated virus rep78 binds to e2-responsive element 1 of bovine papillomavirus type 1.adeno-associated virus type-2 (aav-2) is a helper-dependent parvovirus that has been implicated in the inhibition of replication and oncogenic transformation of bovine papillomavirus type-1 (bpv-1) and other transforming dna viruses. previous studies have suggested that the rep78 protein of aav-2 is a key player mediating this effect. in this report we have analyzed the effect of aav-2 rep78 protein on the regulation of gene expression of a reporter gene under the control of the long control reg ...199910632568
stable maintenance of linear bovine papillomavirus 1 molecules in c127i cells.this paper describes the characterization of cell lines that stably maintain linear copies of bovine papillomavirus 1 (bpv-1). cell lines were generated by liposome-mediated transfection of bamh1-linearized virus into c127i cells. two transfectants with morphologies differing from each other and from that of the parental cell line were characterized. southern blots indicated that they contain ten to twelve copies of the bpv-1 genome per cell and that the predominant species in both cell lines ar ...199910643966
construction and production of fluorescent papillomavirus-like particles.the green fluorescent protein (gfp) from the jellyfish aequorea victoria has attracted widespread interest since it was demonstrated to be fluorescent in vivo when expressed in other organisms. in order to investigate papillomavirus life cycle which hampered by the unavailability of conventional cell culture system, we constructed a chimeric bovine papillomavirus (bpv) type 1 virus-like particles (vlps) containing gfp. it was found that fluorescent vlps could be assembled from l2 protein in whic ...199912840887
papillomavirus virus-like particles for the delivery of multiple cytotoxic t cell epitopes.chimeric papillomavirus (pv) virus-like particles (vlps) based on the bovine papillomavirus type 1 (bpv-1) l1 protein were constructed by replacing the 23-carboxyl-terminal amino acids of the bpv1 major protein l1 with an artificial "polytope" minigene, containing known ctl epitopes of human pv16 e7 protein, hiv iiib gp120 p18, nef, and reverse transcriptase (rt) proteins, and an hpv16 e7 linear b epitope. the ctl epitopes were restricted by three different mhc class i alleles (h-2(b), h-2(d), h ...200010915608
feline papillomas and papillomaviruses.papillomaviruses (pvs) are highly species- and site-specific pathogens of stratified squamous epithelium. although pv infections in the various felidae are rarely reported, we identified productive infections in six cat species. pv-induced proliferative skin or mucous membrane lesions were confirmed by immunohistochemical screening for papillomavirus-specific capsid antigens. seven monoclonal antibodies, each of which reacts with an immunodominant antigenic determinant of the bovine papillomavir ...200010643975
alpha6 integrin is not the obligatory cell receptor for bovine papillomavirus type 4.recently, alpha6 integrin has been proposed as the epithelial cell receptor for papillomavirus. this study investigated whether alpha6 integrin is the cellular receptor for bovine papillomavirus type 4 (bpv-4), which is strictly epitheliotropic and infects the mucous epithelium of the upper digestive tract. primary bovine mucosal keratinocytes from the palate of a foetus (palk) displayed high levels of alpha6 integrin; matched primary fibroblasts from the same biopsy (palf) expressed almost no a ...200010644830
golgi alkalinization by the papillomavirus e5 oncoprotein.the e5 oncoprotein of bovine papillomavirus type i is a small, hydrophobic polypeptide localized predominantly in the golgi complex. e5-mediated transformation is often associated with activation of the pdgf receptor (pdgf-r). however, some e5 mutants fail to induce pdgf-r phosphorylation yet retain transforming activity, suggesting an additional mechanism of action. since e5 also interacts with the 16-kd pore-forming subunit of the vacuolar h(+)-atpase (v-atpase), the oncoprotein could conceiva ...200010648563
n-butyrate mediated inhibition of papovavirus dna replication in vivo and in cell culture: a mechanistic approach.n-butyrate, an inhibitor of g1-to-s transition inhibits papovavirus dna replication in cell culture. to explore the efficacy of n-butyrate in vivo and to better understand its mechanism, we studied the effect of n-butyrate on viral dna replication in mice acutely infected with polyomavirus and in the papovavirus-infected cells in culture. newborn mice treated with n-butyrate stop growing and become runted. when infected with polyomavirus, these mice show a strong overall inhibition of viral dna. ...200010949947
rapid induction of senescence in human cervical carcinoma cells.expression of the bovine papillomavirus e2 regulatory protein in human cervical carcinoma cell lines repressed expression of the resident human papillomavirus e6 and e7 oncogenes and within a few days caused essentially all of the cells to synchronously display numerous phenotypic markers characteristic of cells undergoing replicative senescence. this process was accompanied by marked but in some cases transient alterations in the expression of cell cycle regulatory proteins and by decreased tel ...200011005870
transformation of mortal human fibroblasts and activation of a growth inhibitory pathway by the bovine papillomavirus e5 oncoprotein.the 44-amino acid bovine papillomavirus e5 protein induces tumorigenic transformation of immortal rodent fibroblasts by binding to and activating the platelet-derived growth factor beta receptor (pdgfbetar). here e5 was expressed in mortal human diploid fibroblasts (hdfs), which lack the accumulated genetic changes that are present in immortal rodent cells. e5 induced focus formation and morphological transformation of hdfs without inducing anchorage independence or immortalization. similar effe ...200010939593
crystal structure of the dna binding domain of the replication initiation protein e1 from papillomavirus.papillomaviral infection causes both benign and malignant lesions and is a necessary cause of cervical carcinoma. replication of this virus requires the replication initiation proteins e1 and e2, which bind cooperatively at the origin of replication (ori) as an (e1)2-(e2)2-dna complex. this is a precursor to larger e1 complexes that distort and unwind the ori. we present the crystal structure of the e1 dna binding domain refined to 1.9 a resolution. residues critical for dna binding are located ...200010949036
relationship between retroviral dna integration and gene expression.although retroviruses can integrate their dna into a large number of sites in the host genome, factors controlling the specificity of integration remain controversial and poorly understood. to assess the effects of transcriptional activity on integration in vivo, we created quail cell clones containing a construct with a minigene cassette, whose expression is controlled by the papilloma virus e2 protein. from these clones we derived transcriptionally active subclones expressing the wild-type e2 ...200010954538
the platelet-derived growth factor beta receptor as a target of the bovine papillomavirus e5 protein.the 44-amino acid e5 protein of bovine papillomavirus is a homo-dimeric, transmembrane protein that transforms cells by activating the platelet-derived growth factor ss receptor in a ligand-independent fashion. the e5 protein induces receptor activation by forming a stable complex with the receptor, thereby inducing receptor dimerization, trans-phosphorylation of tyrosine residues in the cytoplasmic domain of the receptor, and recruitment of cellular sh2 domain-containing proteins into a signal ...200010959076
e2f-rb complexes assemble and inhibit cdc25a transcription in cervical carcinoma cells following repression of human papillomavirus oncogene expression.expression of the bovine papillomavirus e2 protein in cervical carcinoma cells represses expression of integrated human papillomavirus (hpv) e6/e7 oncogenes, followed by repression of the cdc25a gene and other cellular genes required for cell cycle progression, resulting in dramatic growth arrest. to explore the mechanism of repression of cell cycle genes in cervical carcinoma cells following e6/e7 repression, we analyzed regulation of the cdc25a promoter, which contains two consensus e2f bindin ...200010982822
a recombinant vaccinia virus containing the papilloma e2 protein promotes tumor regression by stimulating macrophage antibody-dependent cytotoxicity.human papillomavirus infection is associated with cervical cancer. the e6 and e7 papillomavirus proteins are normally required for the maintenance of the malignant phenotype. expression of these proteins in infected cells is negatively regulated by the binding of the papilloma e2 protein to the long terminal control region of the papilloma virus genome. the e2 protein can also promote cell arrest and apoptosis in hela cells. therefore, it is clear that this protein has the potential of inhibitin ...200010999461
sumo-1 modification of bovine papillomavirus e1 protein is required for intranuclear accumulation.the e1 protein is a multifunctional, origin-binding helicase that is essential for replication of papillomaviruses. recently, bovine papillomavirus e1 was shown to be post-translationally modified by the addition of the sumo-1 polypeptide. here we show that the site of sumoylation maps to lysine residue 514. this lysine and the flanking sequences are well conserved in human papillomavirus (hpv) e1 proteins. both hpv1a and hpv18 e1 proteins are substrates for sumoylation in vitro, which is consis ...200011005821
interaction with cbp/p300 enables the bovine papillomavirus type 1 e6 oncoprotein to downregulate cbp/p300-mediated transactivation by p53.the e6 oncoprotein of bovine papillomavirus type 1 (bpv-1) can transform cells independently of p53 degradation. the precise mechanisms underlying this transformation are not yet completely understood. here it is shown that bpv-1 e6 interacts with cbp/p300 in the same way as described for the e6 proteins of oncogenic human papillomaviruses. this interaction results in an inhibition of the transcriptional coactivator function of cbp/p300 required by p53 and probably by other transcription factors ...200011038372
interaction of the papillomavirus transcription/replication factor, e2, and the viral capsid protein, l2.the minor capsid protein l2 of papillomaviruses (pvs) likely plays a role in the selective encapsidation of pv dna in viral capsids and in the infectivity of pv virions. the l2 protein also can cause the relocalization of the pv early protein, e2ta, to nuclear subdomains known as promyelocytic leukemia oncogenic domains (pods) in which it is localized. e2ta is a transcriptional transactivator that also plays a critical role in viral dna replication. in this study, we investigated whether l2, in ...200011040122
utilization of the bovine papillomavirus type 1 late-stage-specific nucleotide 3605 3' splice site is modulated by a novel exonic bipartite regulator but not by an intronic purine-rich element.bovine papillomavirus type 1 (bpv-1) late gene expression is regulated at both transcriptional and posttranscriptional levels. maturation of the capsid protein (l1) pre-mrna requires a switch in 3' splice site utilization. this switch involves activation of the nucleotide (nt) 3605 3' splice site, which is utilized only in fully differentiated keratinocytes during late stages of the virus life cycle. our previous studies of the mechanisms that regulate bpv-1 alternative splicing identified three ...200011044105
repression of human papillomavirus oncogenes in hela cervical carcinoma cells causes the orderly reactivation of dormant tumor suppressor pathways.most cervical carcinomas express high-risk human papillomaviruses (hpvs) e6 and e7 proteins, which neutralize cellular tumor suppressor function. to determine the consequences of removing the e6 and e7 proteins from cervical cancer cells, we infected hela cells, a cervical carcinoma cell line that contains hpv18 dna, with a recombinant virus that expresses the bovine papillomavirus e2 protein. expression of the e2 protein resulted in rapid repression of hpv e6 and e7 expression, followed approxi ...200011070078
distinctive cognate sequence discrimination, bound dna conformation, and binding modes in the e2 c-terminal domains from prototype human and bovine papillomaviruses.the c-terminal dna binding domain of the e2 protein is involved in transcriptional regulation and dna replication in papillomaviruses. at low ionic strength, the domain has a tendency to form aggregates, a process readily reversible by the addition of salt. while fluorescence anisotropy measurements show a 1:1 stoichiometry at ph 5.5, we observed that a second hpv-16 e2 c-terminal dimer can bind per dna site at ph 7.0. this was confirmed by displacement of bis-ans binding, tryptophan fluorescenc ...200011087426
contribution of bovine papillomavirus type 1 e1 protein residue 48 to replication function.the e1 protein of bovine papillomavirus type 1 (bpv-1) is the origin recognition protein and is essential for the initiation of viral dna replication. we reported previously that there is a conserved motif between residues 25 and 60 of all papillomavirus e1 proteins that resembles a casein kinase ii (ckii) phosphorylation site. the corresponding serine in bpv-1, serine-48, is an efficient substrate for ckii in vitro. to examine the functional role of this potential phosphorylation site, three am ...200010900038
the structural basis of dna target discrimination by papillomavirus e2 proteins.the papillomavirus e2 proteins regulate the transcription of all papillomavirus genes and are necessary for viral dna replication. disruption of the e2 gene is commonly associated with malignancy in cervical carcinoma, indicating that e2 has a role in regulating tumor progression. although the e2 proteins from all characterized papillomaviruses bind specifically to the same 12-base pair dna sequence, the cancer-associated human papillomavirus e2 proteins display a unique ability to detect dna fl ...200010906136
identification of a second transforming function in bovine papillomavirus type 1 e6 and the role of e6 interactions with paxillin, e6bp, and e6ap.papillomavirus e6 oncoproteins transform mammalian cells through interaction with cellular proteins. bovine papillomavirus type 1 e6 (be6) interacts with three previously described cellular targets: the e6ap e3 ubiquitin ligase, the calcium-binding protein e6bp (also known as erc-55), and paxillin, which is a focal adhesion adapter protein. be6 interacts strongly with each of these proteins in vitro, binding to similar peptide sequences found in e6ap, e6bp, and paxillin. to determine which be6 i ...200010623743
two patches of amino acids on the e2 dna binding domain define the surface for interaction with e1.the e1 and e2 proteins from bovine papillomavirus bind cooperatively to the viral origin of dna replication (ori), forming a complex which is essential for initiation of dna replication. cooperative binding has two components, in which (i) the dna binding domains (dbds) of the two proteins interact with each other and (ii) the e2 transactivation domain interacts with the helicase domain of e1. by generating specific point mutations in the dbd of e2, we have defined two patches of amino acids tha ...200010627562
interaction of the papillomavirus e2 protein with mitotic chromosomes.the bovine papillomavirus e2 transactivator protein is a multifunctional protein that activates viral transcription, cooperates in initiation of viral dna replication, and is required for long-term episomal maintenance of viral genomes. we have shown previously that the e2 transactivator protein and bovine papillomavirus type 1 genomes are associated with mitotic chromosomes and have proposed that e2 links the genomes to cellular chromosomes to ensure segregation to daughter nuclei. in this stud ...200010772985
mutation correction by homologous recombination with an adenovirus vector. 200010561834
transcription factor-dependent loading of the e1 initiator reveals modular assembly of the papillomavirus origin melting complex.replication of bovine papillomavirus type 1 dna absolutely requires the viral transcription factor e2 as well as the initiator e1, although e1 alone has all the activities expected of an initiator protein. e1 assembles on the dna in a stepwise fashion and undergoes a transition in activities from site-specific dna-binding protein to mobile helicase. complex assembly is assisted by the viral transcription factor e2 at two levels. e2 acts generally as a specificity factor, which through cooperativ ...200010652347
episomal vectors for gene expression in mammalian cells.an important reason for preferring mammalian cells for heterologous gene expression is their ability to make authentic proteins containing post-translational modifications similar to those of the native protein. the development of expression systems for mammalian cells has been ongoing for several years, resulting in a wide variety of effective expression vectors. the aim of this review is to highlight episomal expression vectors. such episomal plasmids are usually based on sequences from dna vi ...200010971576
inhibition of the bovine papillomavirus e2 protein activity by peptide nucleic acid.the bovine papillomavirus type-1 e2 protein is the master regulator of the papillomavirus transcription and replication, the activity of which is regulated through sequence-specific dna binding. peptide nucleic acid (pna) is a nucleic acid analogue, which associates with high affinity to complementary dna, rna or pna, yielding in formation of stable complexes. the potential use of pna as a sequence-specific inhibitor of the e2 protein activity is studied in this report. we demonstrate that repla ...200010653916
binding of bovine papillomavirus type 4 e8 to ductin (16k proteolipid), down-regulation of gap junction intercellular communication and full cell transformation are independent events.the e8 open reading frame of bovine papillomavirus type 4 encodes a small hydrophobic polypeptide that contributes to primary cell transformation by conferring to cells the ability to form foci and to grow in low serum and in suspension. wild-type e8 binds in vitro to ductin, a component of gap junctions, and this binding is accompanied by a loss of gap junction intercellular communication in transformed bovine fibroblasts. however, through the analysis of a panel of e8 mutants, we show here tha ...200010675405
repression of the integrated papillomavirus e6/e7 promoter is required for growth suppression of cervical cancer cells.the human papillomavirus (hpv) e2 protein is an important regulator of viral e6 and e7 gene expression. e2 can repress the viral promoter for e6 and e7 expression as well as block progression of the cell cycle in cancer cells harboring the dna of "high-risk" hpv types. although the phenomenon of e2-mediated growth arrest of hela cells and other hpv-positive cancer cells has been well documented, the specific mechanism by which e2 affects cellular proliferation has not yet been elucidated. here, ...200010684283
position-dependent inhibition of the cleavage step of pre-mrna 3'-end processing by u1 snrnp.the 3' ends of most eukaryotic pre-mrnas are generated by 3' endonucleolytic cleavage and subsequent polyadenylation. 3'-end formation can be influenced positively or negatively by various factors. in particular, u1 snrnp acts as an inhibitor when bound to a 5' splice site located either upstream of the 3'-end formation signals of bovine papilloma virus (bpv) late transcripts or downstream of the 3'-end processing signals in the 5' ltr of the hiv-1 provirus. previous work showed that in bpv it i ...200010688357
parameters that affect in vitro splicing of bovine papillomavirus type 1 late pre-mrnas.during the course of study on regulated viral pre-mrna splicing, an in vitro rna splicing assay was developed to analyze how an exonic splicing enhancer stimulates splicing of bovine papillomavirus type 1 (bpv-1) late pre-mrnas. the optimal concentration of hela nuclear extract (hne) in a standard rna splicing reaction depends on the individual substrate pre-mrna. splicing of a bpv-1 late pre-mrna required 40% hne and 2 h incubation at 30 degrees c. higher hne was detrimental to splicing and lon ...200010716353
monitoring and purification of proteins using bovine papillomavirus e2 epitope tags.we describe here the use of two newly mapped bovine papillomavirus type 1 (bpv-1) e2 protein epitopes as tags. we constructed several vector plasmids for overexpression as well as for moderate expression of single- or double-tagged proteins in either escherichia coli or eukaryotic cells. the new tags were fused to several proteins, and the activity of the tagged proteins was tested in different assays. the tags were shown not to interfere with the function of these proteins in vivo and in vitro. ...200010723557
bovine papillomavirus e5 protein induces the formation of signal transduction complexes containing dimeric activated platelet-derived growth factor beta receptor and associated signaling proteins.the bovine papillomavirus e5 protein binds to the cellular platelet-derived growth factor (pdgf) beta receptor, resulting in constitutive activation of the receptor and cell growth transformation. by subjecting extracts from e5-transformed or pdgf-treated cells to velocity sedimentation in sucrose gradients, activated pdgf beta receptor complexes were separated from monomeric, inactive receptor. rapidly sedimenting activated complexes contained oligomeric (apparently dimeric), tyrosine-phosphory ...200010734138
human tumor growth is inhibited by a vaccinia virus carrying the e2 gene of bovine papillomavirus.papillomavirus is the etiologic agent associated with cervical carcinoma. the papilloma e2 protein is able to regulate negatively the expression of e6 and e7 papilloma oncoproteins. therefore, a new, highly attenuated vaccinia virus known as modified vaccinia virus ankara (mva), which carries the papillomavirus e2 gene, was used for the treatment of tumors associated with human papillomavirus.200010738224
human papillomavirus type 16 e5 protein localizes to the golgi apparatus but does not grossly affect cellular glycosylation.the e5 protein of papillomaviruses is a strongly hydrophobic membrane protein that can associate with the 16 kda protein subunit of the vacuolar proton atpase in endosomes and the golgi apparatus resulting in raise of intraorganelle ph. we demonstrate that e5 of human papillomavirus type 16 (hpv16) when transfected into human keratinocytes localizes to the golgi. using facs analysis and western blotting with a variety of lectins as well as analysing the sialylation status of a specific cell surf ...200011087100
cloning and characterization of a novel caprine genomic repetitive element that hybridizes with papillomavirus dna.a goat genomic library was screened by southern blot hybridization at reduced stringency with a bovine papillomavirus type 5 (bpv 5) dna probe in order to identify potential cellular and viral sequences related to the papillomavirus genome. a recombinant clone with an 8.5 kb genomic insert was found to contain a 1.3 kb psti subfragment (designated as p1-1) that hybridized with the dna of bpv 5, two murine papillomaviruses and human papillomavirus types 5 and 8, but not with dna from another eigh ...200010768774
cell-specific modulation of papovavirus replication by tumor suppressor protein p53.small dna tumor viruses like human papillomaviruses, simian virus 40, and adenoviruses modulate the activity of cellular tumor suppressor proteins p53 and/or prb. these viruses replicate as nuclear multicopy extrachromosomal elements during the s phase of the cell cycle, and it has been suggested that inactivation of p53 and prb is necessary for directing the cells to the s phase. mouse polyomavirus (py), however, modulates only the prb protein activity without any obvious interference with the ...200010775606
production of infectious bovine papillomavirus from cloned viral dna by using an organotypic raft/xenograft technique.bovine papillomavirus type 1 (bpv-1) induces fibropapillomas in its natural host and can transform fibroblasts in culture. the viral genome is maintained as an episome within fibroblasts, which has allowed extensive genetic analyses of the viral functions required for dna replication, gene expression, and transformation. much less is known about bpv-1 gene expression and replication in bovine epithelial cells because the study of the complete viral life cycle requires an experimental system capa ...200010805809
expression vector with dna of bovine papilloma virus 1 for keratinocyte gene therapy.although there are several methods for introducing the genes to keratinocytes in vivo, expression of transgene does not last long enough for effective keratinocyte gene therapy. in this study, we added bovine papilloma virus 1 (bpv) dna into expression vectors with the lacz gene driven by metallothionein and keratin 10 promoters, and we transferred them into keratinocytes in vivo using the naked dna method, and measured beta-gal activity in keratinocytes. the results showed that beta-galactosida ...200010808128
optimization of a weak 3' splice site counteracts the function of a bovine papillomavirus type 1 exonic splicing suppressor in vitro and in vivo.alternative splicing is a critical component of the early to late switch in papillomavirus gene expression. in bovine papillomavirus type 1 (bpv-1), a switch in 3' splice site utilization from an early 3' splice site at nucleotide (nt) 3225 to a late-specific 3' splice site at nt 3605 is essential for expression of the major capsid (l1) mrna. three viral splicing elements have recently been identified between the two alternative 3' splice sites and have been shown to play an important role in th ...200010846071
proteasome-mediated degradation of the papillomavirus e2-ta protein is regulated by phosphorylation and can modulate viral genome copy number.the bovine papillomavirus e2 proteins regulate viral transcription, replication, and episomal genome maintenance. we have previously mapped the major phosphorylation sites of the e2 proteins to serine residues 298 and 301 and shown that mutation of serine residue 301 to alanine leads to a dramatic (10- to 20-fold) increase in viral dna copy number. in this study we analyzed how phosphorylation regulates e2 protein function. s301 is located in a pest sequence; these sequences are often found in p ...200010846085
in vitro determination of carcinogenicity of sixty-four compounds using a bovine papillomavirus dna-carrying c3h/10t(1/2) cell line.a new in vitro test for predicting rodent carcinogenicity is evaluated against a testing database of 64 chemicals including both genotoxic and nongenotoxic carcinogens and carcinogens that normally require addition of an s-9 microsomal fraction for detection in the bacterial mutagenicity assay. the assay uses focus formation in a stable, bovine papillomavirus type 1 (bpv-1) dna carrying c3h/10t(1/2) mouse embryo fibroblast cell line (t1) that does not require transfection, infection with virus, ...200010861948
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