Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| effective generation of transgenic mice by bovine papillomavirus type 1 based self-replicating plasmid that is maintained as extrachromosomal genetic element in three generations of animals. | the objective of our study was to analyze the efficiency and the properties of the inheritance of the bovine papillomavirus type 1 (bpv1) replicator-based plasmid used as vector system for generation of transgenic animals. previously, we have characterized a series of self-replicating plasmid vectors containing all viral factors necessary and sufficient for stable extrachromosomal replication of the bpv1 genome in the tissue culture system. we also demonstrated that the designed replicating vect ... | 2003 | 12749834 |
| transcriptome signature of irreversible senescence in human papillomavirus-positive cervical cancer cells. | a frequent characteristic of human papillomavirus (hpv)-positive cervical cancers is the loss of viral e2 gene expression in hpv-infected cervical epithelial cells as a consequence of viral dna integration into the cellular genome. the expression of e2 in hpv-positive cancer cells results in the repression of the viral e6/e7 oncogenes, activation of the p53 and prb pathways, and a g1 cell cycle arrest, followed by induction of cellular senescence. the transcriptional consequences of e2-mediated ... | 2003 | 12756294 |
| codon optimization of the hpv-16 e5 gene enhances protein expression. | the human papillomavirus type 16 (hpv-16) e5 protein is an 83-amino-acid, hydrophobic polypeptide that has been localized to intracellular membranes when overexpressed in cos-1 cells. while the hpv-16 e5 protein appears to modulate endosomal ph and signal transduction pathways, genetic analysis of its biological activities has been hampered by low (usually nondetectable) levels of expression in stable cell lines. sequence analysis of the native hpv-16 e5 gene revealed that infrequent-use codons ... | 2003 | 12832208 |
| production of functional recombinant tyrosine hydroxylase by the bpv-1 expression plasmids in the cell cultures. | bovine papilloma virus type-1 (bpv-1)-based expression plasmids tkbpvth and cgalbpvth encoding the rat tyrosine hydroxylase (th) enzyme have been designed for the development of gene therapy for experimental parkinson's disease. the aim of the present work was to examine the transfection of bpvth plasmids to express a dopaminergic transgene in the monkey cv1-p fibroblast, rat c6 glioma and human nha astrocyte cell cultures. the biological function of the transgene was estimated by analyzing the ... | 2003 | 14597011 |
| comparison of the structure and dna-binding properties of the e2 proteins from an oncogenic and a non-oncogenic human papillomavirus. | human papillomaviruses (hpvs) that infect the genital tract can be divided into two groups: high-risk hpv types, such as hpv 16 and hpv 18, are associated with cancer, low-risk hpv types, such as hpv 6, are associated with benign warts. in both high-risk and low-risk hpv types, the papillomavirus e2 protein binds to four sites within the viral long control region (lcr) and regulates viral gene expression. here, we present the crystal structure of the minimal dna-binding domain (dbd) from the hpv ... | 2003 | 14643661 |
| tyrphostin ag 555 inhibits bovine papillomavirus transcription by changing the ratio between e2 transactivator/repressor function. | the tyrosine kinase inhibitor (tyrphostin) ag 555 selectively interferes with viral transcription in bovine papillomavirus type 1 (bpv-1)-transformed fibroblasts and induces suppression of cyclin-dependent kinase activity and cell cycle arrest. concomitant with inhibition of viral transcription, c-jun was strongly up-regulated, which was consistent with the observation that ag 555 treatment also led to an activation of the mitogen-activated protein kinase pathway by enhancing phosphorylation of ... | 2003 | 12867421 |
| cutaneous fibropapilloma in a mountain lion (felis concolor). | a 12-yr-old mountain lion (felis concolor) developed a 0.5-cm3 raised nonpigmented and nonulcerated mass between the lip and the nasal planum. the tumor was surgically removed and diagnosed histologically as a fibropapilloma. the tumor recurred 1 yr later, at which time it was again excised, and the diagnosis was reconfirmed by biopsy. frozen tissue from the second excision was submitted for polymerase chain reaction testing for papillomavirus. the 176-base pair polymerase chain reaction product ... | 2003 | 12885136 |
| extensive papillomatosis of the bovine upper gastrointestinal tract. | extensive papillomatosis was identified in a heifer born and raised in scotland and a steer born and raised in england. in both cases, the papillomas extended from the mouth and tongue to the reticulum. although cases of florid papillomatosis of the upper gastrointestinal tract occur relatively frequently in cattle grazing on bracken fern in the scottish highlands, no such cases have been reported previously in english cattle. histopathological examination of the papillomas showed that the lesio ... | 2003 | 12921714 |
| quercetin elevates p27(kip1) and arrests both primary and hpv16 e6/e7 transformed human keratinocytes in g1. | our previous work with primary bovine fibroblasts demonstrated that quercetin, a potent mutagen found in high levels in bracken fern (pteridium aquilinum), arrested cells in g1 and g2/m, in correlation with p53 activation. the expression of bovine papillomavirus type 4 (bpv-4) e7 overcame this arrest and lead to the development of tumorigenic cells lines (beniston et al., 2001). given the possible link between papillomavirus infection, bracken fern in the diet and cancer of the upper gastrointes ... | 2003 | 12934110 |
| activation of c-myc contributes to bovine papillomavirus type 1 e7-induced cell proliferation. | inactivation of the tumor suppressor prb by the human papillomavirus (hpv) oncoprotein e7 is a mechanism by which hpv promotes cell growth. the bovine papillomavirus type 1 (bpv-1) e7 does not bind prb efficiently yet is required for full transformation of murine cells by bpv-1. in the present study, we investigated the mechanism of bpv-1 e7-induced cell proliferation. our studies indicate that expression of bpv-1 e7 induces dna synthesis and stimulates cells to enter s phase in quiescent cells. ... | 2003 | 12937171 |
| angiokeratomatous papilloma associated with papillomavirus in a calf. | a female 8-month-old simmental calf was presented with a history of a gradually enlarging mass in the ventral abdominal skin since 4 months of age. the mass was well circumscribed, lightly pigmented, and rough surfaced with many fine fissures and was attached to the skin by a relatively broad pedicle. on cut section, there was a border between the reddish-black stroma and overlying epithelium, including hemorrhagic foci of variable sizes. histologically, the tumor was papillomatous with angioker ... | 2003 | 12949419 |
| two separate replication modes of the bovine papillomavirus bpv1 origin of replication that have different sensitivity to p53. | we have shown previously that transient amplificational replication of reporter plasmids that carry the papillomavirus origin of replication is efficiently blocked by p53 protein in several cell lines. we demonstrate now that the replication of stably maintained episomal bovine papillomavirus bpv1 urr (upstream regulatory region) reporter plasmid is not sensitive to p53. in addition, these two replication modes--initial transient amplificational replication and stable maintenance replication of ... | 2003 | 12951267 |
| sequence variants of bovine papillomavirus e5 detected in equine sarcoids. | the equine sarcoid, one of the most common dermatological lesions in equids, is a benign, locally invasive dermal fibroblastic lesion. previous studies have suggested an association with two bovine papilloma virus (bpv) types, bpv-1 and bpv-2. in the present study, we examined sarcoids from horses from two geographical areas, switzerland and the uk, for the major transforming gene of bpv, e5. we detected bpv dna for the e5 open reading frame and viral e5 rna transcripts in most sarcoids. sequenc ... | 2003 | 12951274 |
| oligomerization of the e5 protein of human papillomavirus type 16 occurs through multiple hydrophobic regions. | the high risk forms of human papillomavirus (hpv) (primarily types 16 and 18) are the leading cause of cervical cancer worldwide. infection results in expression of three oncoproteins, e5, e6, and e7, the latter two being of predominant importance in maintaining a transformed state of the host epithelial cell. while little is known about the role(s) of the hpv e5, the bovine papillomavirus type 1 (bpv1) e5 protein has been well characterized. a study of hpv16 e5 was performed, focusing on the pr ... | 2003 | 12954209 |
| il-10 mediates suppression of the cd8 t cell ifn-gamma response to a novel viral epitope in a primed host. | priming to ag can inhibit subsequent induction of an immune response to a new epitope incorporated into that ag, a phenomenon referred to as original antigenic sin. in this study, we show that prior immunity to a virus capsid can inhibit subsequent induction of the ifn-gamma effector t cell response to a novel cd8-restricted antigenic epitope associated with the virus capsid. inhibition does not involve ab to the virus capsid, as it is observed in animals lacking b cells. cd8-restricted virus-sp ... | 2003 | 14568953 |
| presence of bovine papillomavirus type 2 dna and expression of the viral oncoprotein e5 in naturally occurring urinary bladder tumours in cows. | samples of neoplastic and normal urothelium were obtained from cows originating from areas of southern italy, a region in which chronic enzootic haematuria is endemic and bracken fern infestation is widespread. specimens were analysed for bovine papillomavirus type 2 (bpv-2) dna, bpv-2 e5 expression and telomerase activity. a total of 46 of 60 tumours and 17 of 34 normal bladder mucosa samples harboured bpv-2 dna. analysis of a subset of samples showed e5 protein expression and telomerase activi ... | 2003 | 14573796 |
| quercetin induces structural chromosomal aberrations and uncommon rearrangements in bovine cells transformed by the e7 protein of bovine papillomavirus type 4. | bovine papillomavirus type 4 (bpv-4) and bracken fern are cofactors in the carcinogenesis of the upper gastrointestinal (gi) tract of cattle. an experimental in vitro model system has been developed to analyse the co-operation between the viral transforming protein e7, the cellular ras oncogene and quercetin, one of the mutagens of bracken fern, during neoplastic progression of primary bovine cells. we now report cytogenetic studies of these cells at different stages of malignant transformation: ... | 2003 | 19379326 |
| the dna-binding domain of human papillomavirus type 18 e1. crystal structure, dimerization, and dna binding. | high risk types of human papillomavirus, such as type 18 (hpv-18), cause cervical carcinoma, one of the most frequent causes of cancer death in women worldwide. dna replication is one of the central processes in viral maintenance, and the machinery involved is an excellent target for the design of antiviral therapy. the papillomaviral dna replication initiation protein e1 has origin recognition and atp-dependent dna melting and helicase activities, and it consists of a dna-binding domain and an ... | 2004 | 14593106 |
| efficient intracellular assembly of papillomaviral vectors. | although the papillomavirus structural proteins, l1 and l2, can spontaneously coassemble to form virus-like particles, currently available methods for production of l1/l2 particles capable of transducing reporter plasmids into mammalian cells are technically demanding and relatively low-yield. in this report, we describe a simple 293 cell transfection method for efficient intracellular production of papillomaviral-based gene transfer vectors carrying reporter plasmids. using bovine papillomaviru ... | 2004 | 14694107 |
| transition to an irreversible state of senescence in hela cells arrested by repression of hpv e6 and e7 genes. | inhibition of human papillomavirus (hpv) e6 and e7 transcription by means of the e2 protein of bovine papillomavirus 1 (bpv1) has been shown to induce acute growth arrest in hpv-positive cervical carcinoma cells. this state of arrest is marked by the expression of senescence phenotypes including sa beta-gal activity and lipofuscin accumulation. in this study, we examined the reversibility of these phenotypes by exogenously expressing the e6 and e7 genes into hela cells growth-arrested by the dep ... | 2004 | 14706235 |
| cytotoxic-t-lymphocyte human papillomavirus type 16 e5 peptide with cpg-oligodeoxynucleotide can eliminate tumor growth in c57bl/6 mice. | previously, we identified human papillomavirus type 16 (hpv-16) e5 as a tumor rejection antigen that can induce cytotoxic t lymphocytes (ctls) to protect against tumor growth (d. w. liu et al., j. virol. 74:9083-9089, 2000). in the present study, we further mapped the ctl epitope of e5 protein by analyzing e5-specific cd8(+) gamma interferon-positive (ifn-gamma(+)) double-positive cells in c57bl/6 mice with flow cytometry. the results showed the region spanning amino acids 25 to 33 (vcllirpll) c ... | 2004 | 14722288 |
| analysis of chromatin attachment and partitioning functions of bovine papillomavirus type 1 e2 protein. | recent studies have suggested that the tethering of viral genomes to host cell chromosomes could provide one of the ways to achieve their nuclear retention and partitioning during extrachromosomal maintenance in dividing cells. the data we present here provide firm evidence that the partitioning of the bovine papillomavirus type 1 (bpv1) genome is dependent on the chromatin attachment process mediated by viral e2 protein and its multiple binding sites. on the other hand, the attachment of e2 and ... | 2004 | 14747575 |
| dna fine structure and dynamics in crystals and in solution: the impact of bi/bii backbone conformations. | sugar-phosphate backbone conformations are an important structural element for a complete understanding of specific recognition in nucleic acid-protein interactions. they can be involved both in early stages of target discrimination and in structural adaptation upon binding. in the first part of this study, we have analyzed high-resolution structures of double-stranded b-dna either isolated or bound to proteins, and explored the impact of both the standard bi and the unusual bii phosphate backbo ... | 2004 | 14755572 |
| molecular dynamics simulations of papilloma virus e2 dna sequences: dynamical models for oligonucleotide structures in solution. | the specificity of papilloma virus e2 protein-dna binding depends critically upon the sequence of a region of the dna not in direct contact with the protein, and represents one of the simplest known examples of indirect readout. a detailed characterization of this system in solution is important to the further investigation hypothesis of a structural code for dna recognition by regulatory proteins. in the crystalline state, the e2 dna oligonucleotide sequence, d(accgaattcggt), exhibits three dif ... | 2004 | 14755573 |
| bovine papillomavirus replicative helicase e1 is a target of the ubiquitin ligase apc. | the papillomavirus e1 replicative helicase is essential for replication and maintenance of extrachromosomal viral genomes in infected cells. we previously found that the bovine papillomavirus e1 protein is a substrate of the ubiquitin-dependent proteolytic pathway. here we show that e1 is targeted for degradation by the anaphase-promoting complex (apc). inhibition of apc activity by the specific inhibitor emi1 or point mutations in the d-box and ken-box motifs of e1 stabilize the protein and inc ... | 2004 | 14963168 |
| direct interaction between nucleosome assembly protein 1 and the papillomavirus e2 proteins involved in activation of transcription. | using a yeast two-hybrid screen, we identified human nucleosome assembly protein 1 (hnap-1) as a protein interacting with the activation domain of the transcriptional activator encoded by papillomaviruses (pvs), the e2 protein. we show that the interaction between e2 and hnap-1 is direct and not merely mediated by the transcriptional coactivator p300, which is bound by both proteins. coexpression of hnap-1 strongly enhances activation by e2, indicating a functional interaction as well. e2 binds ... | 2004 | 14966293 |
| casein kinase ii phosphorylation-induced conformational switch triggers degradation of the papillomavirus e2 protein. | the major phosphorylation sites of the bovine papillomavirus e2 transactivator protein are two serine residues, 298 and 301, that are located in a flexible hinge region between the dna binding and transactivation domains. phosphorylation of serine residue 301 promotes ubiquitination and rapid degradation of the e2 protein by the proteasome pathway. to understand the mechanism through which phosphorylation regulates the intracellular levels of this unique papillomavirus regulatory protein, we hav ... | 2004 | 15014086 |
| induction of autoantibodies to ccr5 in macaques and subsequent effects upon challenge with an r5-tropic simian/human immunodeficiency virus. | antibodies against ccr5, the major coreceptor for human immunodeficiency virus type 1 (hiv-1), may have antiviral potential as viral fusion inhibitors. in this study, we generated a virus-like particle (vlp)-based vaccine that effectively breaks b-cell tolerance and elicits autoantibodies against ccr5 in pig-tailed macaques. initial studies in mice identified a polypeptide comprising the n-terminal domain of pig-tailed macaque ccr5 fused to streptavidin that, when conjugated at high density to b ... | 2004 | 15047820 |
| reactivity of human sera in a sensitive, high-throughput pseudovirus-based papillomavirus neutralization assay for hpv16 and hpv18. | sensitive high-throughput neutralization assays, based upon pseudoviruses carrying a secreted alkaline phosphatase (seap) reporter gene, were developed and validated for human papillomavirus (hpv)16, hpv18, and bovine papillomavirus 1 (bpv1). seap pseudoviruses were produced by transient transfection of codon-modified papillomavirus structural genes into an sv40 t antigen expressing line derived from 293 cells, yielding sufficient pseudovirus from one flask for thousands of titrations. in a 96-w ... | 2004 | 15051381 |
| lack of the canonical prb-binding domain in the e7 orf of artiodactyl papillomaviruses is associated with the development of fibropapillomas. | the l-x-c-x-e prb-binding motif of papillomavirus (pv) e7 proteins has been implicated in the immortalization and transformation of the host cell. however, sequencing of the complete genomes of bovine papillomavirus type 3 (bpv-3), bovine papillomavirus type 5 (bpv-5), equine papillomavirus (eqpv) and reindeer (rangifer tarandus) papillomavirus (rpv) supports the notion that the prb-binding motif is not ubiquitous among e7 proteins in the pv proteome. key among the animal groups that lack the pr ... | 2004 | 15105541 |
| hitchhiking without covalent integration. | in eukaryotes, many latent viruses attach to mitotic chromosomes noncovalently for effective partitioning in dividing cells. for different viruses, the cis and trans elements encoded by the episomes have been effectively defined but the chromosomal "receptors" for such tethering have remained elusive. in this issue of cell, give us a first insight into the cellular protein machinery important for animal papillomavirus retention. | 2004 | 15109488 |
| interaction of the bovine papillomavirus e2 protein with brd4 tethers the viral dna to host mitotic chromosomes. | the papillomavirus e2 protein tethers viral genomes to host mitotic chromosomes to ensure genome maintenance. we have identified the bromodomain protein brd4 as a major cellular interacting partner of the bovine papillomavirus e2. brd4 associates with mitotic chromosomes and colocalizes with e2 on mitotic chromosomes. the site of e2 binding maps to the c-terminal domain of brd4. expression of this c-terminal brd4 domain functions in a dominant-negative manner to abrogate the colocalization of e2 ... | 2004 | 15109495 |
| selection and characterization of small random transmembrane proteins that bind and activate the platelet-derived growth factor beta receptor. | growth factor receptors are typically activated by the binding of soluble ligands to the extracellular domain of the receptor, but certain viral transmembrane proteins can induce growth factor receptor activation by binding to the receptor transmembrane domain. for example, homodimers of the transmembrane 44-amino acid bovine papillomavirus e5 protein bind the transmembrane region of the pdgf beta receptor tyrosine kinase, causing receptor dimerization, phosphorylation, and cell transformation. ... | 2004 | 15111056 |
| a sequence-independent strategy for detection and cloning of circular dna virus genomes by using multiply primed rolling-circle amplification. | the discovery of novel viruses has often been accomplished by using hybridization-based methods that necessitate the availability of a previously characterized virus genome probe or knowledge of the viral nucleotide sequence to construct consensus or degenerate pcr primers. in their natural replication cycle, certain viruses employ a rolling-circle mechanism to propagate their circular genomes, and multiply primed rolling-circle amplification (rca) with phi29 dna polymerase has recently been app ... | 2004 | 15113879 |
| role of the retinoblastoma pathway in senescence triggered by repression of the human papillomavirus e7 protein in cervical carcinoma cells. | repression of the endogenous human papillomavirus (hpv) type 18 e7 gene in hela cervical carcinoma cells by the bovine papillomavirus e2 transcription factor activates the retinoblastoma (rb) pathway and induces cells to undergo senescence. to determine whether activation of the rb pathway is responsible for senescence in response to hpv18 e7 repression, we tested the ability of wild-type and mutant e7 proteins to affect the activity of the rb pathway and to modulate senescence in these cells. e ... | 2004 | 15126344 |
| clinical and immunological effects of newcastle disease virus vaccine on bovine papillomatosis. | newcastle disease virus (ndv) has antineoplastic and immunostimulatory properties, and it is currently being clinically tested in anticancer therapy. in order to analyze the immunostimulatory effects of ndv on bovine papillomatosis, we inoculated 14 cows subcutaneously with an attenuated vaccine containing the lasota strain of ndv (ls-ndv). four cows with papillomatosis served as controls. serum samples were collected from each animal 1 h before and, 7 and 21 days after inoculation. in inoculate ... | 2004 | 15127837 |
| the role of dna structure and dynamics in the recognition of bovine papillomavirus e2 protein target sequences. | the papillomavirus e2 transcription and replication factors bind to the dna consensus accgn(4)cggt sequence (e2-bs), through both direct and indirect readout mechanisms. the two symmetric half-sites accg.cggt are highly conserved in the genomes and are hydrogen bound with e2. although e2 does not contact the n4 spacer, the affinities are modulated by the base composition of this dna part. nevertheless, the origin of either the global recognition mechanism or the spacer effect remains unclear, pa ... | 2004 | 15165850 |
| overcoming antigen masking of anti-amyloidbeta antibodies reveals breaking of b cell tolerance by virus-like particles in amyloidbeta immunized amyloid precursor protein transgenic mice. | in prior work we detected reduced anti-abeta antibody titers in abeta-vaccinated transgenic mice expressing the human amyloid precursor protein (app) compared to nontransgenic littermates. we investigated this observation further by vaccinating app and nontransgenic mice with either the wild-type human abeta peptide, an abeta peptide containing the "dutch mutation", e22q, or a wild-type abeta peptide conjugated to papillomavirus virus-like particles (vlps). | 2004 | 15186505 |
| induction of mucosal and systemic neutralizing antibodies against human immunodeficiency virus type 1 (hiv-1) by oral immunization with bovine papillomavirus-hiv-1 gp41 chimeric virus-like particles. | human immunodeficiency virus type 1 (hiv-1) envelope-specific neutralizing antibodies are generated late after initial infection, and the neutralizing antibody response is weak in the infected individuals. administration of neutralizing antibodies such as 2f5 to hiv-1-infected individuals resulted in reductions in viral loads. because hiv-1 is transmitted mainly via mucosa and because hiv-specific neutralizing antibodies reduce hiv-1 in infected individuals, a vaccine that can induce both mucosa ... | 2004 | 15254206 |
| the role of hpv oncoproteins and cellular factors in maintenance of htert expression in cervical carcinoma cells. | e6 and e7 oncoproteins of high risk type hpv modulate activities of host components in cell cycle regulation. many of these factors are also involved in the regulation of telomerase activity or the expression of htert, the catalytic subunit. transcription of e6 and e7 is inhibited by the papillomavirus e2 protein, and ectopic expression of e2 in hela cells has been shown to cause activation of the p53-growth inhibitory pathway and downregulation of the htert gene. in this study, using e2 transdu ... | 2004 | 15262117 |
| broad-spectrum detection of papillomaviruses in bovine teat papillomas and healthy teat skin. | to investigate the prevalence of bovine papillomavirus (bpv) in bovine papilloma and healthy skin, dna extracted from teat papillomas and healthy teat skin swabs was analysed by pcr using the primer pairs fap59/fap64 and my09/my11. papillomavirus (pv) dna was detected in all 15 papilloma specimens using fap59/fap64 and in 8 of the 15 papilloma specimens using my09/my11. in swab samples, 21 and 8 of the 122 samples were pv dna positive using fap59/fap64 and my09/my11, respectively. four bpv types ... | 2004 | 15269358 |
| chromosome aberrations in cattle with chronic enzootic haematuria. | chromosomal aberrations were investigated in 56 cattle with chronic enzootic haematuria (ceh) raised on pastures giving access to bracken fern. of these animals, 27 were slaughtered and showed neoplastic lesions of the urinary bladder. tumour tissue from 11 of the 27 cattle contained bovine papillomavirus type 2 (bpv-2) dna. increased numbers of chromosomal aberrations were seen in all animals with ceh, as compared with 30 control cattle that had had no access to bracken fern. the highest clasto ... | 2004 | 15276863 |
| a computer simulation analysis of the accuracy of partial genome sequencing and restriction fragment analysis in estimating genetic relationships: an application to papillomavirus dna sequences. | determination of genetic relatedness among microorganisms provides information necessary for making inferences regarding phylogeny. however, there is little information available on how well the genetic relationships inferred from different genotyping methods agree with true genetic relationships. in this report, two genotyping methods - restriction fragment analysis (rfa) and partial genome dna sequencing - were each compared to complete dna sequencing as the definitive standard for classificat ... | 2004 | 15279682 |
| trnaser(cga) differentially regulates expression of wild-type and codon-modified papillomavirus l1 genes. | exogenous transfer rnas (trnas) favor translation of bovine papillomavirus 1 wild-type (wt) l1 mrna in in vitro translation systems (zhou et al. 1999, j. virol., 73, 4972-4982). we, therefore, investigated whether papillomavirus (pv) wt l1 protein expression could be enhanced in eukaryotic cells following exogenous trna supplementation. both chinese hamster ovary (cho) and cos1 cells, transfected with pv1 wt l1 genes, effectively transcribed the genes but did not translate them. however, l1 prot ... | 2004 | 15319446 |
| establishment of papillomavirus infection is enhanced by promyelocytic leukemia protein (pml) expression. | previous studies have suggested that most papillomaviruses enter the host cell via clathrin-dependent receptor-mediated endocytosis but have not addressed later steps in viral entry. to examine these events, we followed the localization of l2 and packaged dna after entry of infectious virions or l1/l2 pseudovirions. confocal microscopic analyses of hela cells showed a time-dependent uncoating of capsids in cytoplasmic vesicles and the accumulation of both l2 and viral dna at distinct nuclear dom ... | 2004 | 15383670 |
| downregulation of major histocompatibility complex class i in bovine papillomas. | bovine papillomavirus (bpv) induces papillomas in cattle; in the great majority of cases, these regress due to the host immune response, but they can persist and progress to malignancy. even in the absence of malignant transformation, bpv infection persists for a significant period of time before activation of the host immune system, suggesting that the host immune system is unaware of, or disabled by, bpv. e5 is the major oncoprotein of bpv, which, in addition to its transforming properties, do ... | 2004 | 15448341 |
| brd4: tethering, segregation and beyond. | papillomaviruses segregate their genomes in dividing cells by tethering them to mitotic chromosomes via the viral e2 protein. a recent report has shown that this interaction is mediated by the cellular bromodomain protein brd4. this discovery provides new insight into the mechanism of viral genome segregation and raises many exciting questions about the regulation and nature of the interaction of this complex with mitotic chromosomes. | 2004 | 15539109 |
| cyclin a expression and growth in suspension can be uncoupled from p27 deregulation and extracellular signal-regulated kinase activity in cells transformed by bovine papillomavirus type 4 e5. | as the biochemical detection of bovine papillomavirus type 4 e5 is problematic, a fusion form of e5 and the green fluorescent protein (gfp-e5) was constructed and its characteristics were examined. gfp-e5 was detected in cells by autofluorescence and immunoblotting. like wild-type (wt) e5, gfp-e5 localized in the endomembranes and permitted anchorage-independent (ai) growth. however, unlike wt e5, cells expressing gfp-e5 became quiescent in low serum and failed to sustain expression of cyclins d ... | 2004 | 15557231 |
| the positively charged termini of l2 minor capsid protein required for bovine papillomavirus infection function separately in nuclear import and dna binding. | during the papillomavirus (pv) life cycle, the l2 minor capsid protein enters the nucleus twice: in the initial phase after entry of virions into cells and in the productive phase to mediate encapsidation of the newly replicated viral genome. therefore, we investigated the interactions of the l2 protein of bovine pv type 1 (bpv1) with the nuclear import machinery and the viral dna. we found that bpv1 l2 bound to the karyopherin alpha2 (kap alpha2) adapter and formed a complex with kap alpha2beta ... | 2004 | 15564455 |
| specific in vitro interaction between papillomavirus e2 proteins and tbp-associated factors. | the bovine and human papillomavirus (bpv/hpv) e2 proteins bind specifically to palindromic sequences accgn4cggt that are concentrated within the viral long control region, where they regulate viral oncogene transcription. e2 can activate viral promoters over relatively large distances within the viral genome and was shown to cooperate with a number of cellular transcription factors. transcriptional activator proteins, such as e2, are thought to act, at least in part, by influencing the assembly ... | 2004 | 15564746 |
| proteins of the pias family enhance the sumoylation of the papillomavirus e1 protein. | sumoylation of the papillomavirus (pv) origin binding helicase e1 protein is critical for its function. consequently, factors modulating the sumoylation of e1 could ultimately alter the outcome of a papillomavirus infection. we investigated the role played by phosphorylation and two known sumo e3 ligases, ranbp2 and pias proteins, on the sumoylation of e1. e1 sumoylation was unaffected by phosphorylation as both wild-type and pseudo-phosphorylation mutants of bpv e1 exhibited similar sumoylation ... | 2005 | 15582666 |
| specific locations of hydrophilic amino acids in constructed transmembrane ligands of the platelet-derived growth factor beta receptor. | the 44 amino acid e5 transmembrane protein is the primary oncogene product of bovine papillomavirus. homodimers of the e5 protein activate the cellular pdgf beta receptor tyrosine kinase by binding to its transmembrane domain and inducing receptor dimerization, resulting in cellular transformation. to investigate the role of transmembrane hydrophilic amino acids in receptor activation, we constructed a library of dimeric small transmembrane proteins in which 16 transmembrane amino acids of the e ... | 2005 | 15588835 |
| cutaneous papillomatosis in cattle. | three of four heifers housed together developed multiple cutaneous tumours in the linea alba and on the teats 3 months after the application of plastic muzzle plates with sharp tips to prevent mutual sucking and licking. fibropapilloma with many koilocytes but few intranuclear inclusions was diagnosed histologically. the dermis showed neoplastic fibroblasts and a structureless intercellular matrix, and nonpurulent vasculitis was also recorded. immunohistochemical examination with an antibody aga ... | 2005 | 15629481 |
| conditional mutations in the mitotic chromosome binding function of the bovine papillomavirus type 1 e2 protein. | the papillomavirus e2 protein is required for viral transcriptional regulation, dna replication and genome segregation. we have previously shown that the e2 transactivator protein and bpv1 genomes are associated with mitotic chromosomes; e2 links the genomes to cellular chromosomes to ensure efficient segregation to daughter nuclei. the transactivation domain of the e2 protein is necessary and sufficient for association of the e2 protein with mitotic chromosomes. to determine which residues of t ... | 2005 | 15650176 |
| productive interaction between transmembrane mutants of the bovine papillomavirus e5 protein and the platelet-derived growth factor beta receptor. | the bovine papillomavirus e5 protein is a 44-amino-acid transmembrane protein that transforms cells by binding to the transmembrane region of the cellular platelet-derived growth factor (pdgf) beta receptor, resulting in sustained receptor signaling. however, there are published reports that certain mutants with amino acid substitutions in the membrane-spanning segment of the e5 protein transform cells without activating the pdgf beta receptor. we re-examined several of these transmembrane mutan ... | 2005 | 15650217 |
| an acidic amphipathic helix in the bovine papillomavirus e2 protein is critical for dna replication and interaction with the e1 protein. | the papillomavirus e2 proteins function in viral transcriptional regulation, and genome replication and episomal maintenance. the transactivation domain is essential for these activities. to identify functional regions, a structural model of the bpv1 e2 transactivation domain was used to target surface residues for mutation. mutation of several previously uncharacterized regions yielded proteins specifically disrupted in the replication activity of e2. mutations in an amino-terminal acidic amphi ... | 2005 | 15661142 |
| are transforming properties of the bovine papillomavirus e5 protein shared by e5 from high-risk human papillomavirus type 16? | the e5 proteins of bovine papillomavirus type 1 (bpv-1) and human papillomavirus type 16 (hpv-16) are small (44-83 amino acids), hydrophobic polypeptides that localize to membranes of the golgi apparatus and endoplasmic reticulum, respectively. while the oncogenic properties of bpv-1 e5 have been characterized in detail, less is known about hpv-16 e5 due to its low expression in mammalian cells. using codon-optimized hpv-16 e5 dna, we have generated stable fibroblast cell lines that express equi ... | 2005 | 15661144 |
| transactivation of the cyclin a promoter by bovine papillomavirus type 4 e5 protein. | bovine papillomavirus type 4 (bpv-4) e5 (formerly e8) is a 42-residue hydrophobic, membrane-localised protein that can transform nih-3t3 cells by a poorly defined mechanism. in e5-expressing cells, the observed up-regulation of cyclin a is underpinned by transactivation of the cyclin a promoter. here we show that e5 transactivates the minimal cell cycle-regulated cyclin a promoter in cells both stably and acutely expressing the viral protein. there are no detectable differences between control a ... | 2005 | 15681052 |
| heterologous papillomavirus virus-like particles and human papillomavirus virus-like particle immune complexes activate human langerhans cells. | chimeric human papillomavirus virus-like particles (hpv cvlp) are currently being explored as a therapeutic vaccination strategy against cervical cancer. hpv cvlp are being explored as a result of their interaction with and activation of dendritic cells, a potent antigen-presenting cell. however langerhans cells, another type of antigen-presenting cell, can interact with hpv cvlp especially during mucosal routes of vaccine administration. langerhans cells are not activated by hpv cvlp, utilize a ... | 2005 | 15705478 |
| maturation of papillomavirus capsids. | the papillomavirus capsid is a nonenveloped icosahedral shell formed by the viral major structural protein, l1. it is known that disulfide bonds between neighboring l1 molecules help to stabilize the capsid. however, the kinetics of inter-l1 disulfide bond formation during particle morphogenesis have not previously been examined. we have recently described a system for producing high-titer papillomavirus-based gene transfer vectors (also known as pseudoviruses) in mammalian cells. here we show t ... | 2005 | 15709003 |
| reconstitution of papillomavirus e2-mediated plasmid maintenance in saccharomyces cerevisiae by the brd4 bromodomain protein. | the papillomavirus e2 protein functions in viral transcriptional regulation, dna replication, and episomal genome maintenance. viral genomes are maintained in dividing cells by attachment to mitotic chromosomes by means of the e2 protein. to investigate the chromosomal tethering function of e2, plasmid stability assays were developed in saccharomyces cerevisiae to determine whether the e2 protein could maintain plasmids containing the yeast autonomous replication sequence replication element but ... | 2005 | 15710895 |
| pigmented cutaneous papillomatosis (pigmented epidermal nevus) in three pug dogs; histopathology, electron microscopy and analysis of viral dna by the polymerase chain reaction. | canine pigmented epidermal nevus (cpen) is a skin disorder of some breeds of dog characterized by multiple black plaques of the haired and non-haired skin. three cases of pigmented cutaneous papillomatosis (previously described also as cpen) in pug dogs were investigated histopathologically, immunohistochemically and electron microscopically. additionally, dna analyses with the polymerase chain reaction (pcr) were performed in two cases. many nuclei of the stratum granulosa were diffusely immuno ... | 2005 | 15737339 |
| hpv-18 transformed cells fail to arrest in g1 in response to quercetin treatment. | previous work with primary human keratinocytes demonstrated that quercetin, a potent mutagen found in high levels in bracken fern (pteridium aquilinum), arrested cells in g1 with concomitant elevation of the cyclin-dependent kinase inhibitor (cdki) p27kip1. expression of the human papillomavirus type 16 (hpv-16) e6 and e7 oncoproteins, under transcriptional control of a heterologous promoter, in transformed keratinocytes failed to abrogate this arrest [beniston, r., campo, m.s., 2003. quercetin ... | 2005 | 15763151 |
| opposing effects of bovine papillomavirus type 1 e6 and e7 genes on fas-mediated apoptosis. | programmed cell death (pcd), best exemplified by apoptosis, is a genetically programmed process of cellular destruction that is indispensable for normal development and homeostasis of multicellular organisms. tumor necrosis factor alpha (tnf) and related cytokines are employed by host defenses to eliminate virally infected cells through induction of apoptosis. many viruses have evolved specific gene products to modulate this process. we have recently shown that the bovine papillomavirus type 1 ( ... | 2005 | 15782122 |
| the mitotic chromosome binding activity of the papillomavirus e2 protein correlates with interaction with the cellular chromosomal protein, brd4. | the papillomavirus transcriptional activator, e2, is involved in key functions of the viral life cycle. these include transcriptional regulation, viral dna replication, and viral genome segregation. the transactivation domain of e2 is required for each of these functions. to identify the regions of the domain that mediate binding to mitotic chromosomes, a panel of mutations has been generated and their effect on various e2 functions has been analyzed. a structural model of the bovine papillomavi ... | 2005 | 15795266 |
| expression of cell cycle associated proteins cyclin a, cdk-2, p27kip1 and p53 in equine sarcoids. | equine sarcoids are benign fibroblastic skin tumours affecting equids worldwide. whilst the pathogenesis is not entirely understood, infection with bovine papillomavirus (bpv) types 1 and 2 has been implicated as a major factor in the disease process, however the mechanism by which bpv infection contributes to sarcoid pathology is not clear. in this study, we show that the majority of sarcoids express the bpv-1 major transforming gene e6. further, we demonstrate that sarcoid lesions are not asso ... | 2005 | 15808409 |
| semi-nested pcr for detection and typing of bovine papillomavirus type 2 in urinary bladder and whole blood from cattle with enzootic haematuria. | bovine papillomavirus type 2 (bpv-2) and chronic intoxication by bracken fern ingestion were associated with urinary bladder lesions and the clinical signs of enzootic haematuria in adult cattle. clinically enzootic haematuria is characterized by intermittent haematuria followed by animal death. enzootic haematuria causes considerable economical impact on extensive cattle breeding worldwide. the demonstration of bpv-2 participation in the etiology of bovine urinary bladder carcinoma by conventio ... | 2005 | 15847940 |
| cross-neutralization of cutaneous and mucosal papillomavirus types with anti-sera to the amino terminus of l2. | vaccination with papillomavirus l2 has been shown to induce neutralizing antibodies that protect against homologous type infection and cross-neutralize a limited number of genital hpvs. surprisingly, we found that antibodies to bovine papillomavirus (bpv1) l2 amino acids 1-88 induced similar titers of neutralizing antibodies against human papillomavirus (hpv)16 and 18 and bpv1 pseudoviruses and also neutralized hpv11 native virions. these antibodies also neutralized each of the other pseudovirus ... | 2005 | 15885736 |
| interaction of tsnare syntaxin 18 with the papillomavirus minor capsid protein mediates infection. | the papillomavirus capsid mediates binding to the cell surface and passage of the virion to the perinuclear region during infection. to better understand how the virus traffics across the cell, we sought to identify cellular proteins that bind to the minor capsid protein l2. we have identified syntaxin 18 as a protein that interacts with bovine papillomavirus type 1 (bpv1) l2. syntaxin 18 is a target membrane-associated soluble n-ethylmaleimide-sensitive factor-attachment protein receptor (tsnar ... | 2005 | 15890910 |
| role of papillomavirus e1 initiator dimerization in dna replication. | viral initiator proteins are polypeptides that form oligomeric complexes on the origin of dna replication (ori). these complexes carry out a multitude of functions related to initiation of dna replication, and although many of these functions have been characterized biochemically, little is understood about how the complexes are assembled. here we demonstrate that loss of one particular interaction, the dimerization between e1 dna binding domains, has a severe effect on dna replication in vivo b ... | 2005 | 15956609 |
| interaction of bovine papillomavirus e2 protein with brd4 stabilizes its association with chromatin. | the bovine papillomavirus e2 protein maintains and segregates the viral extrachromosomal genomes by tethering them to cellular mitotic chromosomes. e2 interacts with a cellular bromodomain protein, brd4, to mediate the segregation of viral genomes into daughter cells. brd4 binds acetylated histones and has been observed to diffusely coat mitotic chromosomes in several cell types. in this study, we show that in mitotic c127 cells, brd4 diffusely coated the condensed chromosomes. however, in the p ... | 2005 | 15994786 |
| association of bovine papillomavirus e2 protein with nuclear structures in vivo. | papillomaviruses are small dna viruses which have the capacity to establish a persistent infection in mammalian epithelial cells. the papillomavirus e2 protein is a central coordinator of viral gene expression, genome replication, and maintenance. we have investigated the distribution of bovine papillomavirus e2 protein in nuclei of proliferating cells and found that e2 is associated with cellular chromatin. this distribution does not change during the entire cell cycle. the n-terminal transacti ... | 2005 | 16051845 |
| detection of bovine papillomavirus dna on the normal skin and in the habitual surroundings of horses with and without equine sarcoids. | the purpose of the present study was to examine whether bovine papillomavirus (bpv) dna can be detected on the normal skin and in the habitual surroundings of horses with and without equine sarcoids by means of superficially taken swabs. in affected horses, no significant difference in presence of bpv-dna could be observed between samples obtained from the equine sarcoid surface, from normal skin close to the tumour and from a normal skin site in direct contact with the tumour. from the group of ... | 2005 | 16054896 |
| molecular dynamics studies on free and bound targets of the bovine papillomavirus type i e2 protein: the protein binding effect on dna and the recognition mechanism. | molecular dynamics simulations of a total duration of 30 ns in explicit solvent were carried out on the bpv-1-e2 protein complexed to a high-affinity dna target containing the two hydrogen-bonded accg.cggt half-sites separated by the noncontacted acgt sequence. the analysis of the trajectories focuses on the dna structure and on the dynamics. the data are compared to those issued from recent simulations made on three free targets that recognize e2 with different affinities. e2 does not drastical ... | 2005 | 16055534 |
| induction of mucosal and systemic immune responses against human carcinoembryonic antigen by an oral vaccine. | carcinoembryonic antigen (cea) is a tumor-associated antigen targeted for the development of colorectal tumor vaccines. in this study, we developed papillomavirus pseudoviruses encoding the truncated cea without nh2-terminal signal peptide (pv-cea) as an oral vaccine to induce cea-specific ctl responses. in cea transgenic (cea-tg) mice orally immunized with pv-cea, the immunologic tolerance to cea as a "self-antigen" was overcome and both mucosal and systemic cea-specific cytolytic activities we ... | 2005 | 16061685 |
| bovine papillomavirus e7 transformation function correlates with cellular p600 protein binding. | the e7 oncoprotein of bovine papillomavirus type 1 (bpv-1) is required for the full transformation activity of the virus. however, the mechanism by which e7 contributes to cellular transformation is unknown. to address this question, we used the proteomic approach of tandem affinity purification to identify cellular proteins that are in complex with e7, and identified the 600-kda protein, p600, as a binding partner of e7. the ability of e7 to complex with p600 correlated with its ability to enha ... | 2005 | 16081543 |
| modulation of cell function by small transmembrane proteins modeled on the bovine papillomavirus e5 protein. | viruses have been subjected to intense study because of their medical importance and because they can provide fundamental insights into normal and pathological cellular processes. indeed, much of our knowledge about basic cellular biology and biochemistry was acquired through the study of viruses, and some of medicine's greatest triumphs and challenges involve viruses. since viruses have evolved to exploit important cell processes, they can provide tools and approaches to manipulate cell functio ... | 2005 | 16299535 |
| bovine papillomavirus type-2 (bpv-2) infection and expression of uroplakin iiib, a novel urothelial cell marker, in urinary bladder tumors of cows. | several immunohistochemical markers have been used to define the differentiation pattern of urothelial cell tumors of the urinary bladder. we investigated the expression of the recently characterized uroplakin (up) iiib, an urothelium-specific and differentiation-dependent protein, in 39 urothelial tumors of the urinary bladder in cows that had suffered from chronic enzootic hematuria for several years. bovine papillomavirus type 2 dna was amplified and up iiib protein was detected in all these ... | 2005 | 16301578 |
| episomal maintenance of plasmids with hybrid origins in mouse cells. | bovine papillomavirus type 1 (bpv1), epstein-barr virus (ebv), and human herpesvirus 8 genomes are stably maintained as episomes in dividing host cells during latent infection. the mitotic segregation/partitioning function of these episomes is dependent on single viral protein with specific dna-binding activity and its multimeric binding sites in the viral genome. in this study we show that, in the presence of all essential viral trans factors, the segregation/partitioning elements from both bpv ... | 2005 | 16306599 |
| analysis of adeno-associated virus and hpv interaction. | it is slowly becoming accepted that adeno-associated virus (aav) is another significant factor involved in cervical carcinogenesis. however, unlike human papillomavirus (hpv), which is positively associated with cervical cancer, aav is negatively associated with this cancer. this negative association appears to be through a direct and complex bi-directional interaction between aav and hpv. essentially all assays used for studying hpv can be used for studying the aav-hpv interaction. this is beca ... | 2005 | 16350413 |
| e5 protein of human papillomavirus type 16 selectively downregulates surface hla class i. | papillomaviruses have evolved mechanisms that result in escape from host immune surveillance. the e5 protein is expressed early in papillomavirus infection in the deep layers of the infected epithelium. it is localized to the golgi apparatus (ga) and endoplasmic reticulum. the e5 protein of bovine papillomavirus (bpv) impairs the synthesis and stability of major histocompatibility (mhc) class i complexes and prevents their transport to the cell surface due to retention in the ga. here we show th ... | 2005 | 15386416 |
| brd2/ring3 interacts with a chromatin-binding domain in the kaposi's sarcoma-associated herpesvirus latency-associated nuclear antigen 1 (lana-1) that is required for multiple functions of lana-1. | latency-associated nuclear antigen 1 (lana-1) of kaposi's sarcoma-associated herpesvirus (kshv) mediates the episomal replication of the kshv genome, as well as transcriptional regulation, in latently infected cells. interaction of lana-1 with cellular chromatin is required for both these functions. an n-terminal heterochromatin-binding site in lana-1 is essential for the replication and maintenance of latent episomes, as well as transcriptional regulation. we have recently described a c-termina ... | 2005 | 16227282 |
| evaluation of papillomaviruses associated with cyclosporine-induced hyperplastic verrucous lesions in dogs. | to determine whether cyclosporine a-induced hyperplastic skin lesions of dogs were associated with papillomavirus infections. | 2005 | 16273908 |
| inhibition of e2 binding to brd4 enhances viral genome loss and phenotypic reversion of bovine papillomavirus-transformed cells. | the bovine papillomavirus e2 protein tethers the viral genomes to mitotic chromosomes in dividing cells through binding to the c-terminal domain (ctd) of brd4. expression of the brd4-ctd competes the binding of e2 to endogenous brd4 in cells. here we extend our previous study that identified brd4 as the e2 mitotic chromosome receptor to show that brd4-ctd expression released the viral dna from mitotic chromosomes in bpv-1 transformed cells. furthermore, stable expression of brd4-ctd enhanced the ... | 2005 | 16282494 |
| sarcoids in captive zebras (equus burchellii): association with bovine papillomavirus type 1 infection. | sarcoids were diagnosed in two captive zebras from different facilities. zebra 1 (equus burchellii boehmi) was a 4.5-yr-old, captive-born male that presented with a 9- by 7-cm inguinal mass. seven months after surgical excision of the inguinal mass, the zebra presented with a similar lesion in the right upper eyelid that has relapsed repeatedly and has not responded to treatment including local cisplatin injections and cryosurgery. zebra 2 (of undetermined taxon) was housed at a private wild ani ... | 2005 | 17315460 |
| the e5 protein of bpv-4 interacts with the heavy chain of mhc class i and irreversibly retains the mhc complex in the golgi apparatus. | bpv-4 e5 inhibits transcription of the bovine mhc class i heavy chain (hc) gene, increases degradation of hc and downregulates surface expression of mhc class i by retaining the complex in the golgi apparatus (ga). here we report that transcription inhibition can be alleviated by interferon treatment and the degradation of hc can be reversed by treatment with inhibitors of proteasomes and lysosomes. however, the inhibition of transport of mhc class i to the cell surface is irreversible. we show ... | 2006 | 16288210 |
| high-specific-activity probes and a high-resolution in-gel photo cross-linking assay for protein-dna complexes. | photochemical cross-linking has been widely employed to identify proteins interacting with specific sites on dna. identification of bound proteins usually relies on transfer of a radiolabel from the dna to the protein by cross-linking. we set out to fine-map a small viral replication preinitiation complex composed of two protein dimers bound to dna, the bovine papillomavirus e1e2-ori complex. here we describe a simple method for generating high-specific-activity probes with a phenyl-azide photoa ... | 2006 | 17070767 |
| bovine papillomavirus type 2 detection in the urinary bladder of cattle with chronic enzootic haematuria. | the bovine papillomavirus type 2 (bpv-2) involvement in the aetiology of chronic enzootic haematuria associated to bracken fern ingestion has been suggested for a long time. however, a few reports have shown the presence of the bpv-2 in urinary bladder tumors of cattle. the aim of this study was to investigate the presence of the bpv-2 infection in the urinary bladder of cattle with chronic enzootic haematuria in brazilian cattle herds. sixty-two urinary bladders were collected from adult cattle ... | 2006 | 17072475 |
| chlr1 is required for loading papillomavirus e2 onto mitotic chromosomes and viral genome maintenance. | autonomously replicating dna viruses must evade mitotic checkpoints and actively partition their genomes to maintain persistent infection. the e2 protein serves these functions by tethering papillomavirus episomes to mitotic chromosomes; however, the mechanism remains unresolved. we show that e2 binds chlr1, a dna helicase that plays a role in sister chromatid cohesion. the e2 mutation w130r fails to bind chlr1 and correspondingly does not associate with mitotic chromosomes. viral genomes encodi ... | 2006 | 17189189 |
| structure of the papillomavirus dna-tethering complex e2:brd4 and a peptide that ablates hpv chromosomal association. | many dna viruses that are latent in dividing cells are noncovalent passengers on mitotic chromosomes and require specific viral-encoded and cellular factors for this activity. the chromosomal protein brd4 is implicated in the hitchhiking of bovine papillomavirus-1 (bpv-1), and the viral protein e2 binds to both plasmids and brd4. here, we present the x-ray crystal structure of the carboxy-terminal domain of brd4 in complex with hpv-16 e2, and with this information have developed a brd4-tat fusio ... | 2006 | 17189190 |
| papillomavirus-associated basosquamous carcinoma in an egyptian fruit bat (rousettus aegyptiacus). | a 5-yr-old female egyptian fruit bat (rousettus aegyptiacus) had a small raised pigmented mass removed from the lateral canthus of the left eye. six additional variably sized, raised, smooth to cauliflower-like skin masses were observed randomly distributed throughout the left wing membranes. four masses were removed and diagnosed microscopically as basosquamous carcinomas and papillomas. additional masses, removed 6 mo and 1 yr later, showed bony invasion and squamous differentiation. immunohis ... | 2006 | 17312801 |
| bovine papillomavirus type 1 oncoprotein e5 stimulates the utilization of superoxide radicals in the mouse fibroblast cell line c127. | the major transforming protein of bovine papillomavirus type 1 (bpv-1) is a small hydrophobic polypeptide, the e5 gene product, localized in the cellular membranes and modulating various pathways in the cell. many studies have shown that reactive oxygen species (ros) are essential in several biological processes, including cell transformation by oncogenes, but unregulated ros are highly toxic to cells. we studied the effect of the bovine papillomavirus protein e5 and its mutants on the level of ... | 2006 | 16413007 |
| papillomavirus e1 protein binds to and stimulates human topoisomerase i. | the papillomavirus (pv) e1 helicase plays a direct role in recruiting cellular dna replication factors, such as replication protein a or polymerase alpha-primase, to replicate pv genomes. here, e1 is shown to bind to human topoisomerase i and stimulate its relaxation activity up to sevenfold. the interaction between e1 and topoisomerase i was mapped to the e1 dna binding domain and c terminus. these findings imply a mechanism for the recruitment of topoisomerase i to pv dna replication forks and ... | 2006 | 16415033 |
| variations in the association of papillomavirus e2 proteins with mitotic chromosomes. | the e2 protein segregates episomal bovine papillomavirus (bpv) genomes to daughter cells by tethering them to mitotic chromosomes, thus ensuring equal distribution and retention of viral dna. to date, only the bpv1 e2 protein has been shown to bind to mitotic chromosomes. we assessed the localization of 13 different animal and human e2 proteins from seven papillomavirus genera, and we show that most of them are stably bound to chromosomes throughout mitosis. furthermore, in contrast to the rando ... | 2006 | 16415162 |
| cleavage of the papillomavirus minor capsid protein, l2, at a furin consensus site is necessary for infection. | papillomaviruses (pv) comprise a large family of nonenveloped dna viruses that include the oncogenic pv types that are the causative agents of human cervical cancer. as is true of many animal dna viruses, pv are taken into the cell by endocytosis and must escape from the endosomal compartment to the cytoplasm to initiate infection. here we show that this step depends on the site-specific enzymatic cleavage of the pv minor virion protein l2 at a consensus furin recognition site. cleavage by furin ... | 2006 | 16432208 |
| molecular basis for phosphorylation-dependent, pest-mediated protein turnover. | proteasomal-mediated rapid turnover of proteins is often modulated by phosphorylation of pest sequences. the e2 protein from papillomavirus participates in gene transcription, dna replication, and episomal genome maintenance. phosphorylation of a pest sequence located in a flexible region accelerates its degradation. nmr analysis of a 29 amino acid peptide fragment derived from this region shows ph-dependent polyproline ii and alpha helix structures, connected by a turn. phosphorylation, in part ... | 2006 | 16472750 |
| indirect readout of dna sequence by papillomavirus e2 proteins depends upon net cation uptake. | the papillomavirus e2 proteins bind with high affinity to palindromic dna sequences consisting of two highly conserved four base-pair sequences flanking a variable "spacer" of identical length (accg nnnn cggt). while intimate contacts are observed between the bound proteins and conserved dna in the available co-crystal structures, no contact is seen between the proteins and the spacer dna. the ability of human papillomavirus strain 16 (hpv-16) e2 and bovine papillomavirus strain 1 (bpv-1) e2 to ... | 2006 | 16513133 |
| a phosphorylation map of the bovine papillomavirus e1 helicase. | papillomaviruses undergo a complex life cycle requiring regulated dna replication. the papillomavirus e1 helicase is essential for viral dna replication and plays a key role in controlling viral genome copy number. the e1 helicase is regulated at least in part by protein phosphorylation, however no systematic approach to phosphate site mapping has been attempted. we have utilized mass spectrometry of purified bovine papillomavirus e1 protein to identify and characterize new sites of phosphorylat ... | 2006 | 16524476 |
| interactions of the cellular ccaat displacement protein and human papillomavirus e2 protein with the viral origin of replication can regulate dna replication. | previously, we and others have shown that ccaat displacement protein (cdp) negatively regulates the papillomavirus promoters. overexpression of cdp has been shown to inhibit high-risk human papillomavirus virus (hpv) and bovine papillomavirus dna replication in vivo presumably through reduction in expression of viral replication proteins, e1 and e2. sequence analysis of the hpv origin indicates several potential cdp-binding sites with one site overlapping the e1-binding site. therefore, cdp coul ... | 2006 | 16529788 |
| brd4 is involved in multiple processes of the bovine papillomavirus type 1 life cycle. | brd4 protein has been proposed to act as a cellular receptor for the bovine papillomavirus type 1 (bpv1) e2 protein in the e2-mediated chromosome attachment and mitotic segregation of viral genomes. here, we provide data that show the involvement of brd4 in multiple early functions of the bpv1 life cycle, suggest a brd4-dependent mechanism for e2-dependent transcription activation, and indicate the role of brd4 in papillomavirus and polyomavirus replication as well as cell-specific utilization o ... | 2006 | 16537635 |