Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
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| the crystal structure of the sv40 t-antigen origin binding domain in complex with dna. | dna replication is initiated upon binding of "initiators" to origins of replication. in simian virus 40 (sv40), the core origin contains four pentanucleotide binding sites organized as pairs of inverted repeats. here we describe the crystal structures of the origin binding domain (obd) of the sv40 large t-antigen (t-ag) both with and without a subfragment of origin-containing dna. in the co-structure, two t-ag obds are oriented in a head-to-head fashion on the same face of the dna, and each t-ag ... | 2007 | 17253903 |
| a papillomavirus-like particle (vlp) vaccine displaying hpv16 l2 epitopes induces cross-neutralizing antibodies to hpv11. | peptides of the papillomavirus l2 minor capsid protein can induce antibodies (ab) that neutralize a broad range of human papillomavirus (hpv) genotypes. unfortunately, l2 is antigenically subdominant to l1 in the virus capsid. to induce a strong anti-l2 ab response with cross-neutralizing activity to other mucosal types, chimeric virus-like particles (vlp) were generated in which hpv16 l2 neutralization epitopes (comprising l2 residues 69-81 or 108-120) are inserted within an immunodominant surf ... | 2007 | 17239496 |
| atp-dependent minor groove recognition of ta base pairs is required for template melting by the e1 initiator protein. | template melting is an essential step in the initiation of dna replication, but the mechanism of template melting is unknown for any replicon. here we demonstrate that melting of the bovine papillomavirus type 1 ori is a sequence-dependent process which relies on specific recognition of ta base pairs in the minor groove by the e1 initiator. we show that correct template melting is a prerequisite for the formation of a stable double hexamer with helicase activity and that ori mutants that fail to ... | 2007 | 17202221 |
| nuclear import of bovine papillomavirus type 1 e1 protein is mediated by multiple alpha importins and is negatively regulated by phosphorylation near a nuclear localization signal. | papillomavirus dna replication occurs in the nucleus of infected cells and requires the viral e1 protein, which enters the nuclei of host epithelial cells and carries out enzymatic functions required for the initiation of viral dna replication. in this study, we investigated the pathway and regulation of the nuclear import of the e1 protein from bovine papillomavirus type 1 (bpv1). using an in vitro binding assay, we determined that the e1 protein interacted with importins alpha3, alpha4, and al ... | 2007 | 17192311 |
| 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 |
| 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 |
| human papillomavirus e7 repression in cervical carcinoma cells initiates a transcriptional cascade driven by the retinoblastoma family, resulting in senescence. | this work demonstrates a central role for the retinoblastoma (rb) family in driving the transcriptional program of induced and replicative senescence. hela cervical carcinoma cells rapidly undergo senescence when the human papillomavirus (hpv) type 18 e7 gene in these cells is repressed by the bovine papillomavirus (bpv) e2 protein. this senescence response requires the endogenous rb pathway but not the p53 pathway. microarray analysis 6 days after bpv e2 introduction into hela cells identified ... | 2007 | 17182682 |
| interaction of papillomavirus e2 protein with the brm chromatin remodeling complex leads to enhanced transcriptional activation. | papillomavirus e2 is a sequence-specific dna binding protein that regulates transcription and replication of the viral genome. the transcriptional activities of e2 are typically evaluated by transient transfection of nonreplicating e2-dependent reporters. we sought to address whether e2 activates transcription in an episomal context and its potential interaction with the chromatin remodeling proteins. using an epstein-barr virus-based episomal reporter, we demonstrate that e2 stimulates transcri ... | 2007 | 17151122 |
| bovine papillomavirus infection in equine sarcoids and in bovine bladder cancers. | bovine papillomavirus (bpv) type 2 is involved in carcinogenesis of the urinary bladder in cattle, while bpv-1 is commonly associated with equine sarcoid tumours. in both cases the early viral proteins are expressed, but virion is not produced. given the similarities in bpv biology between the tumours in cattle and horses, bovine bladder cancers and equine sarcoids were compared with respect to physical status, load of viral dna and variability of the e5 open reading frame (orf). rolling circle ... | 2007 | 17150387 |
| detection of bovine papillomavirus type 1 genomes and viral gene expression in equine inflammatory skin conditions. | papillomaviruses are normally strictly species-specific and even under experimental conditions do not usually infect any other host than the natural host. the only documented reports of natural papillomavirus cross-species infection are of bpv-1/bpv-2, which can infect horses and induce equine sarcoids. bpv dna has not been detected in non-sarcoid equine tumours or equine papillomas, but its presence has been reported in some cases of equine dermatitis. in the present study, we show that equine ... | 2007 | 17140693 |
| mitotic kinesin-like protein 2 binds and colocalizes with papillomavirus e2 during mitosis. | mklp2 is a kinesin-like motor protein of the central mitotic spindle required for completion of cytokinesis. papillomavirus e2 is a sequence specific dna binding protein that regulates viral transcription and replication and is responsible for partitioning viral episomes into daughter cells during cell division. we demonstrate that mklp2 specifically associates with the e2 protein during mitosis. using chromatin immunoprecipitation, we show viral genomes are in complex with mklp2 only within thi ... | 2007 | 17135315 |
| genus specific features of bovine papillomavirus e6, e7, e5 and e8 proteins. | six bovine papillomavirus (bpv) types, bpv-1 to -6, have been classified in genera delta-papillomavirus (bpv-1 and -2), epsilon-papillomavirus (bpv-5) and xi-papillomavirus (bpv-3, -4 and -6). in addition, 16 unclassified putative bpv types have been reported. in the present study, we characterized genus specific features of e6, e7, e5 (formerly e8) and e8 proteins of seven putative bpv types, bapv-1, -2, -3, -4 and -10, baa-5 and bpv-3c. these putative bpv types were classified in genera epsilo ... | 2007 | 17126443 |
| bovine papillomavirus type-2 dna and expression of e5 and e7 oncoproteins in vascular tumours of the urinary bladder in cattle. | cattles suffering from chronic enzootic haematuria frequently develop urinary bladder tumours of both epithelial and mesenchymal origin mainly haemangioma and its malignant counterpart. the role of the bovine papillomavirus type-2 (bpv-2) and of its major transforming oncoprotein in naturally occurring urothelial carcinogenesis has been recently clarified. e5 interacts in vivo as in vitro with the beta receptor for the platelet-derived growth factor (pdgf). however, studies regarding tumours of ... | 2007 | 17125915 |
| e6ap-dependent degradation of dlg4/psd95 by high-risk human papillomavirus type 18 e6 protein. | in most cervical cancers, dnas of high-risk mucosotropic human papillomaviruses (hpvs), such as types 16 and 18, are maintained so as to express two viral proteins, e6 and e7, suggesting that they play important roles in carcinogenesis. the carboxy-terminal pdz domain-binding motif of the e6 proteins is in fact essential for transformation of rodent cells and induction of hyperplasia in e6-transgenic mouse skin. to date, seven pdz domain-containing proteins, including dlg1/hdlg, which is a human ... | 2007 | 17121805 |
| 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 |
| 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 |
| nucleocytoplasmic shuttling of bovine papillomavirus e1 helicase downregulates viral dna replication in s phase. | the papillomavirus e1 protein is essential for the initiation of viral replication. we previously showed that the bovine papillomavirus e1 protein is unstable and becomes resistant to ubiquitin-mediated degradation when tightly bound to cyclin e-cyclin-dependent kinase 2 (cdk2) before the start of dna synthesis. however, neither the protection nor the targeted degradation of e1 appears to depend on its phosphorylation by cdk. here, we report that cdk phosphorylation of e1 is also not a prerequis ... | 2007 | 17035309 |
| replicative helicases: a staircase with a twist. | the first crystal structure of a ring helicase encircling single-stranded dna reveals a mechanism for atp-dependent dna translocation. | 2006 | 17027480 |
| interferon-beta treatment of cervical keratinocytes naturally infected with human papillomavirus 16 episomes promotes rapid reduction in episome numbers and emergence of latent integrants. | following integration of human papillomavirus (hpv) into the host genome, overexpression of the viral oncogenes e6 and e7 requires loss of the transcriptional repressor functions of e2. a key step in hpv-related carcinogenesis is therefore clearance of residual viral episomes, which encode e2. as spontaneous loss of hpv-16 episomes in vitro is associated with increased expression of antiviral genes inducible by type i interferon (ifn), we used the w12 model to examine the effects of exogenous if ... | 2006 | 16973673 |
| brd4 is required for e2-mediated transcriptional activation but not genome partitioning of all papillomaviruses. | bromodomain protein 4 (brd4) has been identified as the cellular binding target through which the e2 protein of bovine papillomavirus type 1 links the viral genome to mitotic chromosomes. this tethering ensures retention and efficient partitioning of genomes to daughter cells following cell division. e2 is also a regulator of viral gene expression and a replication factor, in association with the viral e1 protein. in this study, we show that e2 proteins from a wide range of papillomaviruses inte ... | 2006 | 16973557 |
| characterization of the functional activities of the bovine papillomavirus type 1 e2 protein single-chain heterodimers. | papillomaviruses are small dna viruses which establish persistent infection in the epithelial tissue of various animal species. three papillomavirus proteins encoded by the bovine papillomavirus type 1 e2 open reading frame have a common c-terminal dna binding and dimerization domain and function as dimeric proteins in the regulation of viral gene expression, genome replication, and maintenance. the full-length e2 protein, expressed usually at the lowest level of the three, is an activator, whil ... | 2006 | 16943289 |
| kaposi's sarcoma-associated herpesvirus latency-associated nuclear antigen interacts with bromodomain protein brd4 on host mitotic chromosomes. | the latency-associated nuclear antigen (lana) of kaposi's sarcoma-associated herpesvirus (kshv) is required for viral episome maintenance in host cells during latent infection. two regions of the protein have been implicated in tethering lana/viral episomes to the host mitotic chromosomes, and lana chromosome-binding sites are subjects of high interest. because previous studies had identified bromodomain protein brd4 as the mitotic chromosome anchor for the bovine papillomavirus e2 protein, whic ... | 2006 | 16940503 |
| the recognition of local dna conformation by the human papillomavirus type 6 e2 protein. | the e2 proteins are transcription/replication factors from papillomaviruses. human papillomaviruses (hpvs) can be broadly divided in two groups; low-risk hpv subtypes cause benign warts while high-risk hpvs give rise to cervical cancer. although a range of crystal structures of e2 dna-binding domains (dbd) from both high- and low-risk hpv subtypes have been reported previously, structures of e2 dbd:dna complexes have only been available for high-risk hpv18 and bovine papillomavirus (bpv1). in th ... | 2006 | 16914454 |
| suprabasal overexpression of beta-1 integrin is induced by bovine papillomavirus type 1. | in a normal stratified squamous epithelium, beta1-integrin is expressed in basal epithelial cells. in bpv-induced fibropapillomas beta1-integrin is overexpressed and aberrantly localized, with uniform expression in the lower spinous layer, and sporadic expression within the mid-spinous region that co-localizes with expression of the viral e5 and e7 oncoproteins. in situ hybridization of fibropapillomas for beta1-integrin rna revealed sporadic hybridization in the spinous layer, indicating transc ... | 2006 | 16899269 |
| role of atp hydrolysis in the dna translocase activity of the bovine papillomavirus (bpv-1) e1 helicase. | the e1 protein of bovine papillomavirus type-1 is the viral replication initiator protein and replicative helicase. here we show that the c-terminal approximately 300 amino acids of e1, that share homology with members of helicase superfamily 3 (sf3), can act as an autonomous helicase. e1 is monomeric in the absence of atp but assembles into hexamers in the presence of atp, single-stranded dna (ssdna) or both. a 16 base sequence is the minimum for efficient hexamerization, although the complex p ... | 2006 | 16893956 |
| papillomavirus-like particles are an effective platform for amyloid-beta immunization in rabbits and transgenic mice. | immunization with amyloid-beta (abeta) prevents the deposition of abeta in the brain and memory deficits in transgenic mouse models of alzheimer's disease (ad), opening the possibility for immunotherapy of ad in humans. unfortunately, the first human trial of abeta vaccination was complicated, in a small number of vaccinees, by cell-mediated meningoencephalitis. to develop an abeta vaccine that lacks the potential to induce autoimmune encephalitis, we have generated papillomavirus-like particles ... | 2006 | 16888028 |
| partitioning viral genomes in mitosis: same idea, different targets. | papillomavirus infections are long-lived and persistent. the circular dna of the viral genome is maintained in dividing epithelial cells as an extrachromosomal element. the e2 protein of the virus binds to the viral genome and tethers it to mitotic chromosomes to ensure that the genome is retained and faithfully partitioned in dividing cells. this mechanism has been best studied for bovine papillomavirus type 1. recent evidence indicates that while this is a common strategy among papillomaviruse ... | 2006 | 16861919 |
| mechanism of dna translocation in a replicative hexameric helicase. | the e1 protein of papillomavirus is a hexameric ring helicase belonging to the aaa + family. the mechanism that couples the atp cycle to dna translocation has been unclear. here we present the crystal structure of the e1 hexamer with single-stranded dna discretely bound within the hexamer channel and nucleotides at the subunit interfaces. this structure demonstrates that only one strand of dna passes through the hexamer channel and that the dna-binding hairpins of each subunit form a spiral 'sta ... | 2006 | 16855583 |
| surface mutagenesis of the bovine papillomavirus e1 dna binding domain reveals residues required for multiple functions related to dna replication. | the e1 protein from papillomaviruses is a multifunctional protein with complex functions required for the initiation of viral dna replication. we have performed a surface mutagenesis of the well-characterized e1 dna binding domain (dbd). we demonstrate that substitutions of multiple residues on the surface of the e1 dbd are defective for dna replication without affecting the dna binding activity of the protein. the defects of individual substitutions include failure to form the double trimer tha ... | 2006 | 16840329 |
| induction of human immunodeficiency virus type-1-specific immunity with a novel gene transport unit (gtu)-multihiv dna vaccine. | a multihiv fusion gene expressing an antigenic fusion protein composed of regulatory hiv-1 proteins rev, nef, and tat, as well as gag p17/p24 and a stretch of 11 cytotoxic t lymphocyte (ctl) epitope clusters from pol and env, was cloned into a novel dna vector named the gene transport unit (gtu). a mouse h-2(d)-restricted hiv-1 gp120 epitope (rgpgrafvti) was cloned into the fusion gene as well. in addition to the hiv- 1 genes the gtu codes for a nuclear anchoring protein (bovine papilloma virus ... | 2006 | 16831091 |
| the e5 oncoprotein of bpv-4 does not interfere with the biosynthetic pathway of non-classical mhc class i. | the major histocompatibility complex (mhc) class i region in mammals contains both classical and non-classical mhc class i genes. classical mhc class i molecules present antigenic peptides to cytotoxic t lymphocytes, whereas non-classical mhc class i molecules have a variety of functions. both classical and non-classical mhc molecules interact with natural killer cell receptors and may under some circumstances prevent cell death by natural killer cytotoxicity. the e5 oncoprotein of bpv-4 down-re ... | 2006 | 16806386 |
| papillomavirus virus-like particles activate the pi3-kinase pathway via alpha-6 beta-4 integrin upon binding. | we have previously shown that human papillomavirus virus-like particles (vlps) are able to activate the ras/map kinase pathway. ras can also elicit an anti-apoptotic signal via pi3-kinase so we investigated this further. here we show that binding of vlps from hpv types 6b, 18, 31, 35 and bpv1 results in activation of pi3-kinase. activation was achieved by either l1 or l1/l2 vlps and was dependent on both vlp-cell interaction and correct conformation of the virus particle. vlp-induced pi3-kinase ... | 2006 | 16781758 |
| common determinants in dna melting and helicase-catalysed dna unwinding by papillomavirus replication protein e1. | e1 and t-antigen of the tumour viruses bovine papillomavirus (bpv-1) and simian virus 40 (sv40) are the initiator proteins that recognize and melt their respective origins of replication in the initial phase of dna replication. these proteins then assemble into processive hexameric helicases upon the single-stranded dna that they create. in t-antigen, a characteristic loop and hairpin structure (the pre-sensor 1beta hairpin, ps1betah) project into a central cavity generated by protein hexameriza ... | 2006 | 16738139 |
| papillomatosis in a european bison. | five european bison (bison bonasus) from three european zoos were shipped to the bukovské vrchy hills (slovakia) in june 2004 and kept together in an acclimatization enclosure. the european bison were released into the wild in december 2004. at that time, papillomas were found at the medial canthus of the left eye of a 12-yr-old female bison. cutaneous papillomatosis was confirmed histologically. negative stain transmission electron microscopic examination revealed papillomavirus in the papillom ... | 2006 | 16699157 |
| saccharomyces cerevisiae: a useful model host to study fundamental biology of viral replication. | understanding the fundamental steps of virus life cycles including virus-host interactions is essential for the design of effective antiviral strategies. such understanding has been deferred by the complexity of higher eukaryotic host organisms. to circumvent experimental difficulties associated with this, systems were developed to replicate viruses in the yeast saccharomyces cerevisiae. the systems include viruses with rna and dna genomes that infect plants, animals and humans. by using the pow ... | 2006 | 16698107 |
| chaperone-mediated in vitro disassembly of polyoma- and papillomaviruses. | hsp70 chaperones play a role in polyoma- and papillomavirus assembly, as evidenced by their interaction in vivo with polyomavirus capsid proteins at late times after virus infection and by their ability to assemble viral capsomeres into capsids in vitro. we studied whether hsp70 chaperones might also participate in the uncoating reaction. in vivo, hsp70 co-immunoprecipitated with polyomavirus virion vp1 at 3 h after infection of mouse cells. in vitro, prokaryotic and eukaryotic hsp70 chaperones ... | 2006 | 16641302 |
| dynamic localization of the human papillomavirus type 11 origin binding protein e2 through mitosis while in association with the spindle apparatus. | papillomaviral dna replicates as extrachromosomal plasmids in squamous epithelium. viral dna must segregate equitably into daughter cells to persist in dividing basal/parabasal cells. we have previously reported that the viral origin binding protein e2 of human papillomavirus types 11 (hpv-11), 16, and 18 colocalized with the mitotic spindles. in this study, we show the localization of the hpv-11 e2 protein to be dynamic. it colocalized with the mitotic spindles during prophase and metaphase. at ... | 2006 | 16641272 |
| cellular topoisomerase i modulates origin binding by bovine papillomavirus type 1 e1. | in addition to viral proteins e1 and e2, bovine papillomavirus type 1 (bpv1) depends heavily on host replication machinery for genome duplication. it was previously shown that e1 binds to and recruits cellular replication proteins to the bpv1 origin of replication, including dna polymerase alpha-primase, replication protein a (rpa), and more recently, human topoisomerase i (topo i). here, we show that topo i specifically stimulates the origin binding of e1 severalfold but has no effect on nonori ... | 2006 | 16611895 |
| bromodomain protein 4 mediates the papillomavirus e2 transcriptional activation function. | the papillomavirus e2 regulatory protein has essential roles in viral transcription and the initiation of viral dna replication as well as for viral genome maintenance. brd4 has recently been identified as a major e2-interacting protein and, in the case of the bovine papillomavirus type 1, serves to tether e2 and the viral genomes to mitotic chromosomes in dividing cells, thus ensuring viral genome maintenance. we have explored the possibility that brd4 is involved in other e2 functions. by anal ... | 2006 | 16611886 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| bovine papillomavirus e5 oncoprotein binds to the activated form of the platelet-derived growth factor beta receptor in naturally occurring bovine urinary bladder tumours. | studies regarding the functions of the bovine papillomavirus (bpv) e5 oncoprotein in vivo are lacking and no e5-mediated mechanism underlying epithelial carcinogenesis is known. we have shown that bpv-2 dna is present in the majority of naturally occurring urinary bladder tumours of cattle and that e5 is expressed in the cancer cells. here we show that the interaction between the platelet-derived growth factor (pdgf) beta receptor and bpv e5, described in vitro in cultured cells, takes place in ... | 2006 | 16205631 |
| similarities and differences between the e5 oncoproteins of bovine papillomaviruses type 1 and type 4: cytoskeleton, motility and invasiveness in e5-transformed bovine and mouse cells. | bovine papillomaviruses (bpvs) are oncogenic viruses. in cattle, bpv-1/2 is associated with urinary bladder cancer and bpv-4 with upper gi tract cancer. bpv e5 is a small hydrophobic protein localised in the endoplasmic reticulum (er) and golgi apparatus (ga). e5 is the major transforming protein of bpvs, capable of inducing cell transformation in cultured mouse fibroblasts and, in cooperation with e7, in primary bovine cells. e5-induced cell transformation is accompanied by activation of severa ... | 2006 | 16168512 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |