| identification of conformational epitopes of the bpv-1 capsid recognized by competitive inhibition of sera from infected or immunized animals. | conformational papillomavirus (pv) capsid epitopes are the major targets of neutralizing antibodies. bpv1 virion surface epitopes were analyzed for type-specificity, induction of neutralization, and topographical location with antibodies from selected humans, and bpv1 or -2 immunized or infected cattle, rabbits and mice. rabbit sera produced against deer pv (dpv) or bpv2 and human sera reacted with intact bpv1 in elisa, indicating the presence of cross-reactive conformational epitopes on the sur ... | 1993 | 8216835 |
| effect of gamma-interferon or cycloheximide treatment on viral and c-myc transcripts in bovine-papillomavirus-type-1-transformed primary mouse fibroblasts. | we have studied the effect of gamma-interferon (ifn-gamma) treatment on the transcription of viral and c-myc oncogenes in bovine papillomavirus type 1 (bpv-1)-transformed mouse fibroblast cell lines. upon ifn-gamma treatment, viral transcripts always decreased in cell lines containing episomal bpv-1 dna, while the effect was variable in cell lines containing integrated bpv-1 dna. two series of tumour cell lines established by in vivo passage of b6b71 (episomal) and b6b31-j (integrated) cells via ... | 1993 | 8225910 |
| the v-sis protein retains biological activity as a type ii membrane protein when anchored by various signal-anchor domains, including the hydrophobic domain of the bovine papilloma virus e5 oncoprotein. | membrane-anchored forms of the v-sis oncoprotein have been previously described which are oriented as type i transmembrane proteins and which efficiently induce autocrine transformation. several examples of naturally occurring membrane-anchored growth factors have been identified, but all exhibit a type i orientation. in this work, we wished to construct and characterize membrane-anchored growth factors with a type ii orientation. these experiments were designed to determine whether type ii memb ... | 1993 | 8227125 |
| detection of human papillomavirus l1 protein in condylomata acuminata from adults with defects in cell-mediated immunity. | immunohistochemical assays for human papillomavirus (hpv) l1 protein, using antiserum directed against the l1 major capsid protein of bovine papillomavirus (anti-bpv serum), were performed on 101 condylomata acuminata biopsy samples from 47 men (40 of whom had intact cell mediated immunity [cmi], and 7 with conditions known to cause cmi defects), and 54 women (48 with normal cmi, and 6 with cmi defects). l1 protein was detected in 28% of all biopsies, including 20.5% of samples from patients wit ... | 1993 | 8228942 |
| two e2 binding sites (e2bs) alone or one e2bs plus an a/t-rich region are minimal requirements for the replication of the human papillomavirus type 11 origin. | human papillomaviruses (hpvs) cannot be propagated in vitro, but the dna can be replicated transiently in an assay in the presence of two trans-acting viral proteins, e1 and e2. using this assay, we have defined the minimal cis-acting elements of the origin of replication of hpv type 11. most hpv genomes are conserved at the origin of replication, and the core contains three e2 binding sites (e2bs) surrounding an a/t-rich spacer region. the present results show that the minimal requirement for r ... | 1993 | 8230435 |
| the human t-cell leukemia/lymphotropic virus type i p12i protein cooperates with the e5 oncoprotein of bovine papillomavirus in cell transformation and binds the 16-kilodalton subunit of the vacuolar h+ atpase. | the human t-cell leukemia/lymphotropic virus type i (htlv-i) induces t-cell leukemia and transforms human t cells in vitro. a recently identified protein with a molecular weight of 12,000 (12k) (p12i), encoded by single- and double-spliced mrnas transcribed from the 3' end of the htlv-i genome, has been shown to localize in the perinuclear compartment and in the cellular endomembranes. the p12i protein exhibits significant amino acid sequence similarity to the e5 oncoprotein of bovine papillomav ... | 1993 | 8230493 |
| enrichment for metallothionein does not confer resistance to cisplatin in transfected nih/3t3 cells. | evidence has been presented both that metallothionein does and does not produce resistance to cisplatin. the metallothionein-enriched cells described in most previous studies have been selected for resistance to heavy metals, such as cadmium, or have been maintained in a medium enriched for the metals. exposure to toxic metals could alter the cells in many ways. this report addresses the effect of metallothionein content alone, independent of exposure to metals, on cellular resistance to cisplat ... | 1993 | 8246143 |
| replication of human papillomavirus (hpv) dnas supported by the hpv type 18 e1 and e2 proteins. | transient replication of human papillomavirus (hpv) type 18 dna was shown to require the viral e1 and e2 proteins. a 108-bp sequence within the long control region (nucleotides 12 to 119) was sufficient to function as the origin, but maximal replication required a region of 177 bp from positions 7800 to 7857 and 1 to 119 of hpv-18. the e1 and e2 proteins of hpv-18 also supported transient replication of plasmids containing the origins of hpv-1a and bovine papillomavirus type 1 to low levels. int ... | 1994 | 8254762 |
| a population-based seroepidemiological study of cervical cancer. | the epidemiology of cervical cancer indicates the presence of a sexually transmitted risk factor, attributable at least in part to infection with human papillomavirus (hpv) type 16 or 18. we performed a seroepidemiological study of hpv and cervical cancer in the counties of västerbotten and norrbotten in northern sweden, a low-risk area for cervical cancer. sera from 94 cases of incident cervical cancer were matched against 188 age- and sex-matched controls derived from a population-based blood ... | 1994 | 8261434 |
| protein-sulfenic acid stabilization and function in enzyme catalysis and gene regulation. | sulfenic acids (r-soh) result from the stoichiometric oxidations of thiols with mild oxidants such as h2o2; in solution, however, these derivatives accumulate only transiently due to rapid self-condensation reactions, further oxidations to the sulfinic and/or sulfonic acids, and reactions with nucleophiles such as r-sh. in contrast, oxidations of cysteinyl side chains in proteins, where disulfide bond formation can be prevented and where the reactivity of the nascent cysteine-sulfenic acid (cys- ... | 1993 | 8262333 |
| mapping of linear b cell epitopes on capsid proteins of bovine papillomavirus: identification of three external type-restricted epitopes. | immunodominant, conserved and type-restricted external epitopes of bovine papillomavirus (bpv) major (l1) capsid protein have been identified using bpv particles and synthetic peptides. antisera to disrupted bpv-1 recognized bpv-1 and bpv-2 particles in immune electron microscopy (iem) studies and inhibited bpv-2-induced focus formation of nih/3t3 cells. thus bpv-1/bpv-2 cross-reactive epitopes occur on the surface of virions. the l1 protein appeared to be immunodominant as the antisera reacted ... | 1993 | 8277272 |
| the bovine papillomavirus type 1 (bpv1) replication protein e1 modulates transcriptional activation by interacting with bpv1 e2. | the study of bovine papillomavirus type 1 (bpv1) dna replication has shown that e1 and e2 are the only viral proteins required for this process. both e1 and e2 interact with the viral origin of replication (ori). the bpv1 e2 protein is also a well-characterized transcriptional regulator. we show in this report that e1 can modulate transcription by interactions with e2. at low concentrations, e1 enhanced the e2-mediated transactivation of heterologous promoters containing the bpv1 ori by promotin ... | 1994 | 8289338 |
| dna binding specificity of the bovine papillomavirus e1 protein is determined by sequences contained within an 18-base-pair inverted repeat element at the origin of replication. | bovine papillomavirus type 1 (bpv-1) dna replicates episomally and requires two virally expressed proteins, e1 and e2, for this process. both proteins bind to the bpv-1 genome in the region that functions as the origin of replication. the binding sequences for the e2 protein have been characterized previously, but little is known about critical sequence requirements for e1 binding. using a bacterially expressed e1 fusion protein, we examined binding of the bpv-1 e1 protein to the origin region. ... | 1994 | 8289339 |
| human papillomavirus type 11 e2 proteins repress the homologous e6 promoter by interfering with the binding of host transcription factors to adjacent elements. | the e6 promoter of human papillomaviruses (hpvs) trophic for epithelia for the lower genital tract and the upper respiratory tract is regulated in vitro by homologous and heterologous papillomaviral e2 proteins that bind to a consensus responsive sequence (e2-rs) accn6ggt. when hpv type 11 (hpv-11) expression is examined in epithelial cell lines, the hpv-11 e2-c protein, which lacks the amino-terminal transactivating domain of the full-length e2 protein, invariably represses the homologous viral ... | 1994 | 8289341 |
| e1 protein of human papillomavirus is a dna helicase/atpase. | replication of human papillomavirus (hpv) dna requires the viral proteins e1 and e2. amino acid similarities to sv40 large-t antigen had suggested that e1 is a dna helicase/atpase involved in initiating viral dna replication, and this has recently been shown for bovine papillomavirus type 1 (bpv-1) e1 protein. however, in vitro analysis of hpv e1 has been hampered by the inability to produce purified protein using heterologous expression systems. we have succeeded in demonstrating atpase and dna ... | 1993 | 8290339 |
| cooperativity in vivo between the e2 transactivator and the tata box binding protein depends on core promoter structure. | the e2 transactivator protein of bovine papillomavirus 1 (bpv-1) can strongly stimulate complex promoters such as that of the herpes simplex virus thymidine kinase gene but does not efficiently activate minimal promoters that only contain e2 binding sites and a tata box. here we show that overexpression of the human, but not yeast, tata box binding protein (tbp) in transfection experiments overcomes this block and enables e2 to activate a minimal tata box-containing promoter. this suggests that ... | 1994 | 8306958 |
| platelet-derived growth factor receptor can mediate tumorigenic transformation by the bovine papillomavirus e5 protein. | we showed previously that the beta receptor for platelet-derived growth factor (pdgf) is constitutively activated in fibroblasts transformed by the 44-amino-acid bovine papillomavirus type 1 (bpv) e5 protein and that the e5 protein and the pdgf receptor exist in a stable complex in e5-transformed fibroblasts. on the basis of these results, we proposed that activation of the pdgf receptor by the bpv e5 protein generates a sustained proliferative signal, resulting in fibroblast transformation. in ... | 1993 | 8321218 |
| papillomavirus e7 protein binding to the retinoblastoma protein is not required for viral induction of warts. | human papillomaviruses (hpvs) are the etiologic agents responsible for benign epithelial proliferative disorders including genital warts and are a contributory factor in the pathogenesis of cervical cancer. hpvs demonstrate strict species and cell-type specificity, which is manifested by the inability of these viruses to induce disease in any species other than humans. the natural history of hpv infection in humans is closely mimicked by cottontail rabbit papillomavirus (crpv) infection in domes ... | 1993 | 8380462 |
| bovine papilloma virus (bpv)-encoded e1 protein contains multiple activities required for bpv dna replication. | replication of bovine papilloma virus (bpv) dna requires two virus-encoded proteins, e1 and e2, while all other proteins are supplied by the host cell. here, we describe the isolation of the e1 protein and show that it is a multifunctional protein. purified e1 protein was required for the in vitro replication of bpv origin-containing dna by extracts of mouse cells, as reported [yang, l., li, r., mohr, i. j., clark, r. & botchan, m. r. (1991) nature (london) 353, 628-632]. in addition, the e1 pro ... | 1993 | 8380645 |
| bpv-4 induces amplification and activation of 'silent' bpv-1 in a sub-line of c127 cells. | bpv-4-induced malignant transformation of c127 mouse fibroblasts in vitro is the result of a 'hit and run' mechanism. viral dna is lost on continued subculture of transformed cell lines without loss of any malignant characteristics. the dna from these cells harbours specific amplified sequences. two such amplified fragments of approximately 10 kb and 12 kb were molecularly cloned and designated hl-10 and hl-12 respectively. hl-10 transformed c127 cells efficiently and therefore encodes a transfo ... | 1993 | 8380914 |
| the bovine papillomavirus origin of replication requires a binding site for the e2 transcriptional activator. | the bovine papillomavirus type i transcriptional activator e2 is essential for replication of bovine papillomavirus dna, yet most of the high-affinity binding sites for e2 are dispensable. here we demonstrate an absolute requirement for a binding site for the e2 polypeptide as a cis-acting replication element, establishing that site-specific binding of e2 to the origin is a prerequisite for bovine papillomavirus replication in vivo. the position and distance of the e2 binding site relative to th ... | 1993 | 8381536 |
| the e1 replication protein of bovine papillomavirus type 1 contains an extended nuclear localization signal that includes a p34cdc2 phosphorylation site. | bovine papillomavirus (bpv) dna replication occurs in the nucleus of infected cells. most enzymatic activities are carried out by host cell proteins, with the viral e1 and e2 proteins required for the assembly of an initiation complex at the replication origin. in latently infected cells, viral dna replication occurs in synchrony with the host cell chromosomes, maintaining a constant average copy number of bpv genomes per infected cell. by analyzing a series of mutants of the amino-terminal regi ... | 1993 | 8382303 |
| regulation of the human papillomavirus type 11 e6 promoter by viral and host transcription factors in primary human keratinocytes. | human papillomavirus (hpv) type 11 is strictly trophic for epithelial cells and induces benign condylomata of the external genitalia and also causes laryngeal papillomas. primary keratinocytes are the appropriate hosts for studies of hpv gene regulation, but they are not frequently used, owing to difficulties in culturing and low transfection efficiencies. by modifying a polybrene transfection procedure, we achieved consistently high transfection efficiencies in primary human foreskin keratinocy ... | 1993 | 8382318 |
| binding of bovine papillomavirus e1 to the origin is not sufficient for dna replication. | replication of the bovine papillomavirus (bpv-1) dna requires both the viral e1 and e2 gene products. the minimal origin of replication, which resides in a 60-basepair fragment centered on the unique hpai site of the bpv-1 genome, can be bound by the e1 protein and is flanked by e2 binding sites. the integrity of the region surrounding the unique hpai restriction enzyme site is important for e1 binding and dna replication, but the e2 binding sites are not required. the ability of e1 to complex w ... | 1993 | 8382395 |
| in situ hybridisation of equine sarcoids with bovine papilloma virus. | | 1993 | 8383371 |
| in vitro evaluation of phosphorothioate oligonucleotides targeted to the e2 mrna of papillomavirus: potential treatment for genital warts. | papillomaviruses induce benign proliferative lesions, such as genital warts, in humans. the e2 gene product is thought to play a major role in the regulation of viral transcription and dna replication and may represent a rational target for an antisense oligonucleotide drug action. phosphorothioate oligonucleotides complementary to e2 mrnas were synthesized and tested in a series of in vitro bovine papillomavirus (bpv) and human papillomavirus (hpv) models for the ability to inhibit e2 transacti ... | 1993 | 8383937 |
| analysis of the transforming functions of bovine papillomavirus type 4. | bovine papillomavirus type 4 (bpv-4) morphologically transforms primary bovine cells in vitro only in the presence of an activated ras gene. the transformed cells are capable of anchorage-independent growth, but are not immortal and are incapable of inducing tumors in nude mice. bpv-4 does not possess an e6 orf and failure to induce full transformation may be due to the lack of this gene. here we report the contribution of individual bpv-4 genes to cell transformation and the effect of adding th ... | 1993 | 8384749 |
| bovine papilloma virus (bpv)-encoded e2 protein enhances binding of e1 protein to the bpv replication origin. | the replication of bovine papilloma virus (bpv) dna in vivo requires two viral-encoded proteins, e1 and e2, while all other proteins are derived from the host. we described previously the isolation of the e1 protein and showed that it contains multiple functions required for bpv dna replication. the bpv transcription factor e2 was shown by others to stimulate bpv dna replication in vitro. here, we present results that account for the role of the e2 protein. the e1 protein bound selectively to th ... | 1993 | 8385347 |
| sites of predicted stress-induced dna duplex destabilization occur preferentially at regulatory loci. | this paper describes a computational method to predict the sites on a dna molecule where imposed superhelical stresses destabilize the duplex. several dna sequences are analyzed in this way, including the pbr322 and cole1 plasmids, bacteriophage f1, and the polyoma and bovine papilloma virus genomes. superhelical destabilization in these molecules is predicted to occur at small numbers of discrete sites, most of which are within regulatory regions. the most destabilized sites include the termina ... | 1993 | 8385354 |
| identification of proteins binding to the f441 locus of polyomavirus b enhancer that are required for its activity in embryonic carcinoma cells. | a point mutation at nucleotide 5233 of the polyomavirus (a2 strain) enables it to overcome growth restriction in undifferentiated embryonal carcinoma cells. we analysed the binding of nuclear proteins from f9 cells to a 38 bp region that spans this site of mutation and encompasses two copies of the bovine papillomavirus core sequence, ccaccc, and characterized this domain by mutational analysis. our results showed that the f441 mutation creates a sequence motif which binds tef-1 or a tef-1-like ... | 1993 | 8385690 |
| synthesis and assembly of infectious bovine papillomavirus particles in vitro. | bovine papillomavirus type 1 (bpv-1) virions were produced in vitro using vaccinia virus (vv) recombinants expressing the bpv-1 l1 and l2 capsid proteins. particles morphologically resembling papillomaviruses were observed in the nucleus of cells infected with a vv recombinant for the bpv-1 l1 protein, and greater numbers of similar particles were seen in the nuclei of cells infected with a vv double recombinant for l1 and l2. virus-like particles (vlps) assembled in cells infected with the vv d ... | 1993 | 8385700 |
| characterization of human papillomavirus type 11 e1 and e2 proteins expressed in insect cells. | the study of human papillomavirus replication has been hampered by the lack of an in vitro system which reliably supports virus replication. recent results from the bovine papillomavirus (bpv) system indicate that the e1 and e2 proteins are the only viral gene products required for replication. by analogy with simian virus 40 large t antigen, e1 is thought to possess atpase and helicase activity, which may play a direct role in viral dna replication. the precise role of e2 is unclear, but it may ... | 1993 | 8386271 |
| the 23-kilodalton e1 phosphoprotein of bovine papillomavirus type 1 is nonessential for stable plasmid replication in murine c127 cells. | the 23-kda protein encoded by the 5' segment of the e1 open reading frame of bovine papillomavirus type 1 (bpv1) was previously ascribed a negative regulatory function for the replication of viral plasmid dna. however, results from recent functional and biochemical studies do not readily support this genetic assignment. therefore, we have reassessed the role of this protein in papillomavirus dna replication by using a mutant of bpv1 which is unable to express this e1 protein. this mutant viral d ... | 1993 | 8386283 |
| t2g4 telomere repeats does not provide telomere function to a bpv-1 containing dna fragment in mouse c127 cells. | the ability of the (t2g4)n telomeric repeats to maintain a linear structure in an extrachromosomal replicating plasmid in mouse c127 cells was tested in a vector based on bovine papillomavirus type-1, ars, his3 and the neo genes. digestion with bamhi releases a bpv-1 containing fragment with a (t2g4)n repeats at each end which was introduced to yeast and microinjected into mouse c127 cells. while the linear construct was maintained as extrachromosomal structure in yeast cells, none of the result ... | 1993 | 8387849 |
| behaviour of plasmid containing c4a2 repeats in s. cerevisiae and s. pombe. | plasmid, which combined the complete genome of bpv-i, yeast ars, leu yeast selectable marker gene, the neo selectable marker gene and inverted (c4a2)n telomeric repeat gene sequences cloned originally from tetrahymena thermophila, was constructed. it was introduced in either circular or linear form to saccharomyces cerevisiae or schizosaccharomyces pombe. although both yeasts could replicate the plasmid extrachromosomally, irrespective of whether it was introduced as a circular or linear structu ... | 1993 | 8387850 |
| enhanced degradation of p53 protein in hpv-6 and bpv-1 e6-immortalized human mammary epithelial cells. | normal mammary epithelial cells are efficiently immortalized by the e6 gene of human papillomavirus (hpv)-16, a virus commonly associated with cervical cancers. surprisingly, introduction of the e6 gene from hpv-6, which is rarely found in cervical cancer, or bovine papillomavirus (bpv)-1, into normal mammary cells resulted in the generation of immortal cell lines. the establishment of hpv-6 and bpv-1 e6-immortalized cells was less efficient and required a longer period in comparison to hpv-16 e ... | 1993 | 8387914 |
| genetic definition of a new bovine papillomavirus type 1 open reading frame, e5b, that encodes a hydrophobic protein involved in altering host-cell protein processing. | we have previously observed that bovine papillomavirus type 1 (bpv-1) induces the appearance of five cellular proteins in c127 mouse fibroblasts, four of which appear to arise by altered processing of resident endoplasmic reticulum proteins. studies of various cell lines revealed that expression of the 3' end of the bpv early region was sufficient for induction of these changes. to identify the bpv gene responsible, we have utilized the simian virus 40 (sv40)/bpv-1 recombinant virus pava-1, whic ... | 1993 | 8388507 |
| the e1 protein of bovine papilloma virus 1 is an atp-dependent dna helicase. | for efficient dna replication of papillomaviruses, only two viral-encoded proteins, e1 and e2, are required. other proteins and factors are provided by the host cell. e2 is an enhancer of both transcription and replication and is known to help e1 bind cooperatively to the origin of dna replication. e1 is sufficient for replication in extracts prepared from permissive cells, but the activity is enhanced by e2. here we show that purified e1 can act as an atp-dependent dna helicase. to measure this ... | 1993 | 8389467 |
| prophylactic and therapeutic vaccination against a mucosal papillomavirus. | papillomaviruses are ubiquitous dna viruses affecting humans and animals and causing a variety of tumours of mucosal and cutaneous epithelia. some of these lesions, particularly those affecting mucosal epithelia, can progress to squamous cell carcinomas. prevention or cure of viral infection would ultimately lead to a decrease in the incidence of papillomavirus-associated cancers. using recombinant proteins, we have developed prophylactic and therapeutic vaccines against bovine papillomavirus ty ... | 1993 | 8389809 |
| inhibition of cervical carcinoma cell line proliferation by the introduction of a bovine papillomavirus regulatory gene. | human papillomavirus (hpv) e6 and e7 oncogenes are expressed in the great majority of human cervical carcinomas, whereas the viral e2 regulatory gene is usually disrupted in these cancers. to investigate the roles of the papillomavirus e2 genes in the development and maintenance of cervical carcinoma, the bovine papillomavirus (bpv) e2 gene was acutely introduced into cervical carcinoma cell lines by infection with high-titer stocks of simian virus 40-based recombinant viruses. expression of the ... | 1993 | 8389903 |
| identification and characterization of novel promoters in the genome of human papillomavirus type 18. | most studies on the regulation of gene expression in human papillomaviruses (hpv) have focused on the promoter for the early genes e6 and e7. this promoter is located at the junction between the long control region and the e6 open reading frame. rna mapping studies have suggested that additional promoters may exist in other parts of the genome. in this study, we used a combination of transcription in vitro and an analysis of rna produced in vivo in transfected cells to identify three novel promo ... | 1993 | 8389929 |
| p3 promoter element of bovine papillomavirus. | the p3 promoter activity of bovine papillomavirus (bpv) and cis-acting dna element of p3 promoter required for transcription were examined using chloramphenicol acetyltransferase (cat) assay. the results show that p3 promoter is a very weak promoter compared to p2 promoter in bpv and e2 transactivator is required for the maximal transcription of p3 promoter in a bpv upstream regulatory region (urr)-dependent manner. deletion experiments by nuclease bal-31 were carried out to define p3 promoter e ... | 1993 | 8390322 |
| the acidic transcriptional activation domains of vp16 and p53 bind the cellular replication protein a and stimulate in vitro bpv-1 dna replication. | for papillomavirus dna replication, the e2 enhancer protein cooperatively assists in binding of the e1 helicase to the origin. we report that, at limiting e1 and e2 levels, the enhancer proteins gal4-vp16 and gal4-p53(1-73) stimulate bpv in vitro dna replication. this cell-free system was used to ascertain whether the acidic activation domains have a cellular target important for replication. cellular extracts were depleted of replication activity by passage through a vp16 affinity column. the p ... | 1993 | 8390328 |
| cooperative assembly of the bovine papilloma virus e1 and e2 proteins on the replication origin requires an intact e2 binding site. | using quantitative gel retardation assays the properties of the bovine papilloma virus (bpv) origin recognition protein e1 and the effect of the viral e2 protein on the binding of e1 to bpv origin dna were examined. as reported previously (seo, y.s., mueller, f., lusky, m., gibbs, e., kim, h.-y., phillips, b. and j. hurwitz (1993) proc. natl. acad. sci. u. s. a. 90, 2865-2869), the e1 protein binds specifically to dna sequences within the bpv origin (ori+) of replication. we also show that the p ... | 1993 | 8393453 |
| a study from south india on the association between the papilloma virus and carcinoma of the penis. | specimens from 39 cases of squamous cell carcinoma of the penis were treated for the papilloma virus using the bovine papilloma virus antibody and the peroxidase-antiperoxidase technique. all 39 cases showed a viral antigen situated intranuclearly, intracytoplasmically or both intranuclearly and intracytoplasmically. no correlation could be seen between the presence of viral antigen and age of patient, duration of lesion, cell morphology and histological grade. the adjacent mucosa and skin were ... | 1993 | 8393502 |
| repression of bovine papillomavirus type 1 transcription by the e1 replication protein. | bovine papillomavirus type 1 (bpv-1) is the prototype virus for the study of papillomavirus gene regulation. the functions of the bpv-1 e2 proteins in transcriptional regulation have been well characterized. the bpv-1 e1 protein is required for viral dna replication and can bind to the origin of replication alone or in a complex with the e2 transactivator protein. in this study, we demonstrated that the bpv-1 e1 protein is also involved in transcriptional regulation. the e1 protein significantly ... | 1993 | 8394436 |
| transformation-specific interaction of the bovine papillomavirus e5 oncoprotein with the platelet-derived growth factor receptor transmembrane domain and the epidermal growth factor receptor cytoplasmic domain. | the bovine papillomavirus e5 transforming protein appears to activate both the epidermal growth factor receptor (egf-r) and the platelet-derived growth factor receptor (pdgf-r) by a ligand-independent mechanism. to further investigate the ability of e5 to activate receptors of different classes and to determine whether this stimulation occurs through the extracellular domain required for ligand activation, we constructed chimeric genes encoding pdgf-r and egf-r by interchanging the extracellular ... | 1993 | 8394451 |
| differentiation-specific expression from the bovine papillomavirus type 1 p2443 and late promoters. | the papillomavirus life cycle is tightly linked with keratinocyte differentiation in squamous epithelia. vegetative viral dna replication begins in the spinous layer, while synthesis of capsid proteins and virus maturation is restricted to the most differentiated or granular layer of the epithelium. in this study, in situ hybridization of bovine fibropapillomas was used to demonstrate that the activity of two promoters of bovine papillomavirus type 1 (bpv-1) is regulated in a differentiation-spe ... | 1993 | 8394463 |
| cooperative dna binding of the bovine papillomavirus e2 transcriptional activator is antagonized by truncated e2 polypeptides. | cooperative dna binding of the bovine papillomavirus type 1 (bpv-1) e2 transcriptional activator (e2-ta) is thought to play a role in the transcriptional synergism of multiple e2-responsive dna elements (j. ham, n. dostatni, j.-m. gauthier, and m. yaniv, trends biochem. sci. 16:440-444, 1991). binding-equilibrium considerations show that such involvement is unlikely, thereby suggesting that the e2-ta cooperative capacity may have evolved to play other, different roles. the role of cooperative in ... | 1993 | 8394466 |
| dna of bovine papillomavirus type 1 and 2 in equine sarcoids: pcr detection and direct sequencing. | nucleotide sequences of bovine papillomavirus (bpv) dna amplified by the polymerase chain reaction (pcr) from samples of equine sarcoid skin tumours were determined. all naturally occurring sarcoids (n = 58 tumours from 32 horses and 2 donkeys) contained bpv-dna. all but 3 of the genome fragments belonged to the bpv type 1 strain (bpv-1); the remaining were bpv type 2. similar results were obtained with cutaneous bovine papillomas used as controls (n = 20). one of the horses, carrying 2 sarcoids ... | 1993 | 8394687 |
| dna-binding domain of bovine papillomavirus type 1 e1 helicase: structural and functional aspects. | the e1 protein of bovine papillomavirus type 1 is a multifunctional enzyme required for papillomaviral dna replication. it assists in the initiation of replication both as a site-specific dna-binding protein and as a dna helicase. previous work has indicated that at limiting e1 concentrations, the e2 protein is required for efficient e1 binding to the replication origin. in this study, we have defined the domain of the e1 protein required for site-specific dna binding. experiments with a series ... | 1993 | 8396665 |
| importance of the bovine papillomavirus p2443 promoter in the regulation of e2 and e5 expression. | the full-length bovine papillomavirus e2 gene product (e2ta), which has a direct role in dna replication and functions as a transcriptional activator, can be expressed from an unspliced mrna transcribed from the p2443 promoter or from spliced mrnas transcribed from other upstream promoters. the regulation of e2 expression from these promoters is still in question. in the background of wild-type protein coding sequences, this study identified the p2443 promoter as the major source of e2ta as well ... | 1993 | 8396681 |
| human papillomavirus and cutaneous warts in meat handlers. | the association of papillomavirus and hand warts in meat handlers was examined. human papillomavirus (hpv) dna was found in 23 (88%) of 26 cutaneous warts, with hpv 7 (27%) and a yet unidentified hpv (hpv x) (42%) being the predominant types. hpv 2 was found in two (7.5%) patients, and hpv 4 was found in three (11.5%) patients. no bovine papillomavirus sequences were detected. in most patients, the warts developed in less than 2 years after they started working with meat. a possible hpv transmis ... | 1993 | 8408588 |
| interaction between bovine papillomavirus type 4 and cocarcinogens in the production of malignant tumours. | bovine fetal palatine tissue infected with bovine papillomavirus type 4 (bpv-4) was implanted subcutaneously in athymic nude mice. the implants developed into cysts containing papillomas essentially the same as those in the natural host. in order to investigate the interaction of cocarcinogens with bpv-4 in cell transformation, the virus-infected implants were exposed in vivo to either the tumour promoter 12-o-tetradecanoylphorbol-13-acetate (tpa) or the tumour initiator 7,12-dimethylbenz[a]-ant ... | 1993 | 8409951 |
| the conserved c-terminal domain of the bovine papillomavirus e5 oncoprotein can associate with an alpha-adaptin-like molecule: a possible link between growth factor receptors and viral transformation. | the bovine papillomavirus e5 gene encodes an oncoprotein that can independently transform rodent fibroblasts. this small 44-amino-acid protein is thought to function through the activation of growth factor receptors. e5 activation of the epidermal growth factor receptor results in an increase in the number of activated receptors at the cell surface. this finding suggests that e5 may act by inhibiting the normal down regulation of activated epidermal growth factor receptor via coated pit-mediated ... | 1993 | 8413245 |
| alanine mutagenesis of conserved residues in the platelet-derived growth factor family: identification of residues necessary for dimerization and transformation. | platelet-derived growth factor (pdgf) and vascular endothelial growth factor define a family of dimeric proteins characterized by eight conserved cysteine residues involved in disulfide bonds. thirteen non-cysteine residues conserved among the platelet-derived/vascular endothelial growth factors were individually mutated to alanine in v-sis/pdgf-b. in addition, five other residues flanking f148 were also mutated to alanine. the resulting mutants were assayed for transformation of nih3t3 cells, a ... | 1993 | 8437840 |
| the p12i, p13ii, and p30ii proteins encoded by human t-cell leukemia/lymphotropic virus type i open reading frames i and ii are localized in three different cellular compartments. | three protein isoforms are encoded by the human t-cell leukemia/lymphotropic virus type i px region open reading frames (orf) i and ii through alternative splicing. both the singly and doubly spliced mrnas from orf i encode a single 12-kda protein (p12i), whereas two distinct proteins of 13 kda (p13ii) and 30 kda (p30ii) are encoded from the orf ii alternatively spliced mrna. because the p12i protein is very hydrophobic and poorly immunogenic, we genetically engineered its cdna by adding a short ... | 1993 | 8445734 |
| e2 represses the late gene promoter of human papillomavirus type 8 at high concentrations by interfering with cellular factors. | the late gene promoter p7535 of the epidermodysplasia verruciformis-associated human papillomavirus type 8 (hpv8) is regulated by the viral e2 protein. transfection experiments performed with the human skin keratinocyte cell line rts3b and p7535 reporter plasmids revealed transactivation at low amounts and a repression of basal promoter activity at high amounts of e2 expression vector. this repression was promoter specific and correlated with the amount of transiently expressed e2 protein. mutat ... | 1996 | 8523515 |
| amino acids critical for the functions of the bovine papillomavirus type 1 e2 transactivator. | the n-terminal domain of the bovine papillomavirus type 1 e2 protein is important for viral dna replication, for transcriptional transactivation, and for interaction with the e1 protein. to determine which residues of this 200-amino-acid domain are important for these activities, single conservative amino acid substitutions have been generated in 17 residues that are invariant among all papillomavirus e2 proteins. the resulting mutated e2 proteins were tested for the ability to support viral dna ... | 1996 | 8523530 |
| early phase in the infection of cultured cells with papillomavirus virions. | the fate of full bovine papillomavirus (bpv) virions and virus-like particles after binding to c127 or cv-1 cells was studied by electron microscopy and indirect immunofluorescence. after incubation at 4 degrees for 1 hr, bpv virions were found to be bound to the plasma membrane, and most viruses were absorbed by the cells after 30 min incubation at 37 degrees. ninety minutes after the virions had been bound to the plasma membrane, the uptake of the virions was completed and most of the antigen ... | 1995 | 8525612 |
| bovine papillomavirus type 4 in australia. | | 1995 | 8534233 |
| the bovine papillomavirus type 1 e2 transactivator and repressor proteins use different nuclear localization signals. | the e2 gene of bovine papillomavirus type 1 encodes at least three nuclear phosphoproteins that regulate viral transcription and dna replication. all three proteins have a common c-terminal domain that has dna-binding and dimerization activities. a basic region in this domain forms an alpha helix which makes direct contact with the dna target. in this study, it is shown that in addition to its role in dna binding, this basic region functions as a nuclear localization signal both in the e2 dna-bi ... | 1996 | 8551571 |
| co-operative interaction between the initiator e1 and the transcriptional activator e2 is required for replicator specific dna replication of bovine papillomavirus in vivo and in vitro. | the e1 polypeptide from bovine papillomavirus binds to the origin of replication (ori) and possesses the activities attributed to initiator proteins. e1 is also the only viral protein required for replication in a cell-free replication system. replication in vivo, however, absolutely requires in addition the viral transcription factor e2. we demonstrate that the basis for this distinction between in vitro and in vivo requirements is the limited sequence specificity of the e1 protein. e1 and e2, ... | 1995 | 8557041 |
| bpv e1 protein alters the kinetics of cell cycle entry of serum starved mouse fibroblasts. | a stable bovine papillomavirus e1 expressing cell line (c2e1) was used to investigate the effects of e1 protein on the requirement for growth factors during serum-induced reentry from quiescence to proliferation. flow cytometric bivariate dna/pcna analysis was utilized to study the expression of proliferating cell nuclear antigen (pcna) concomitant with this transition. c2e1 cells, unlike the control cells (cneo), were able to reenter the cell cycle when stimulated with low serum (1%). stimulati ... | 1995 | 8582248 |
| [bovine papillomavirus vector]. | | 1995 | 8584697 |
| cis and trans requirements for stable episomal maintenance of the bpv-1 replicator. | papillomavirus genomes are maintained as multicopy nuclear plasmids in transformed cells. to address the mechanisms by which the viral dna is stably propagated in the transformed cells, we have constructed a cell line ch04.15 expressing constitutively the viral proteins e1 and e2, that are required for initiation of viral dna replication. we show that these viral proteins are necessary and sufficient for stable extrachromosomal replication. using the cell line ch04.15, we have shown that the bov ... | 1996 | 8598191 |
| the bpv-1 e2 dna-contact helix cysteine is required for transcriptional activation but not replication in mammalian cells. | the papillomavirus e2 protein contains an amino-terminal region thought necessary and sufficient to support transcriptional activation and a carboxy-terminal region shown to direct sequence-specific dna binding and dimerization. a cysteine residue in the center of the e2 dna recognition helix is highly conserved among papillomavirus e2 proteins. mutations of this cysteine in bovine papillomavirus type 1 e2 to serine and glycine resulted in proteins which failed to activate e2-dependent promoters ... | 1996 | 8599215 |
| stable expression of the reovirus mu2 protein in mouse l cells complements the growth of a reovirus ts mutant with a defect in its m1 gene. | reovirus mu2 protein was constitutively expressed in mammalian cells transfected with dicistronic constructs in which the reovirus m1 gene and the selectable neomycin-resistant gene (neo) were both driven by the same phosphoglycerate kinase promoter. translation of neo was initiated with the cap-independent translation initiation element from encephalomyocarditis virus. expression of mu2 protein was detected by mu2-specific antibody produced through immunization of rabbits with trp-e-mu2 fusion ... | 1996 | 8599234 |
| pituitary-specific chromatin structure of the rat prolactin distal enhancer element. | the location of target dna sequences within chromatin may affect the ability of trans-acting factors to bind cis-elements and regulate gene transcription. to examine the effect of chromatin structure on the ability of the estrogen-estrogen receptor complex (e2r) to bind its respective dna binding element within the rat prolactin (rprl) gene and modulate rprl gene expression, we have developed cell lines derived from the rprl-expressing (rprl+) rat pituitary cell line gh3 and the rprl-non- expres ... | 1996 | 8604340 |
| mapping of hpv-11 e1 binding site and determination of other important cis elements for replication of the origin. | the viral proteins e1 and e2 are essential for the replication of the hpv-11 origin. we have now mapped the e1 binding site (e1bs) and show by mutation analysis that the e1bs and an adjoining poly(a)-rich region are necessary for efficient replication of the origin. we have also shown, using suboptimal levels of e1 protein, that enhancement of e1 binding by e2 partially protects the e1bs. finally, we show that e1 can enhance the binding of e2 even in the absence of the e1bs. | 1996 | 8614991 |
| arsenic and chromium enhance transformation of bovine papillomavirus dna-transfected c3h/10t1/2 cells. | tumor promoters such as phorbol esters, teleocidin and okadaic acid increase the numbers of multilayered, transformed foci produced by bpv dna-transfected c3h/10t1/2 cells. we questioned whether arsenic and chromium, which are known human carcinogens also enhance transformation of bpv dna-transfected c3h/10t1/2 cells. cr(iii) potassium sulfate at 100 microm enhanced transformation by 1.4-fold, but cr(vi) as potassium chromate did not enhance transformation, although toxicity of potassium chromat ... | 1996 | 8616810 |
| perturbation of the host cell cycle and dna replication by the bovine papillomavirus replication protein e1. | a stable cell line expressing the bovine papillomavirus e1 protein (c2e1) was compared with an e1 minus control line (cneo) to study the effects of e1 protein on host cell growth. c2e1 and cneo cells were synchronized either at mitosis or at the g1/s boundary by the cell cycle inhibitors nocodazole and mimosine, respectively. after release from the drug-induced cell cycle block, the progression through the succeeding stages of the cell cycle was temporally monitored using flow cytometry. in addi ... | 1996 | 8623531 |
| virus-like particles of bovine papillomavirus type 4 in prophylactic and therapeutic immunization. | virus-like particles were produced in insect cells containing either the l1 and l2 capsid proteins of bovine papillomavirus type 4 (bpv-4) or only the l1 protein. both preparations of vlps proved to be extremely effective prophylactic vaccines. thirteen of 15 calves immunised with either l1-l2 vlps or l1-vlps were refractory to experimental challenge with high doses of bpv-4 and did not develop papillomas, while 9 of 10 control animals developed multiple oral papillomas. vlps were not efficient ... | 1996 | 8623552 |
| antigenicity of bovine papillomavirus type 1 (bpv-1) l1 virus-like particles compared with that of intact bpv-1 virions. | virus-like-particles (vlps) of various papillomavirus (pv) types have been produced by expressing recombinant l1 proteins in eukaryotic cells. although vlps have the same ultrastructural appearance as native virions and their immunogenicity appears to be similar, their antigenicity has not been carefully evaluated. for this reason, the antigenicity of intact bovine pv type 1 (bpv-1) virions was compared with that of bpv-1 recombinant l1 vlps by elisa using a well-characterized panel of polyclona ... | 1996 | 8627221 |
| sp1 is critical for basal and e2-transactivated transcription from the bovine papillomavirus type 1 p89 promoter. | the bovine papillomavirus type 1 (bpv-1) long control region (lcr) contains at least three consensus binding sites for the transcription factor sp1 at nucleotides (nt) 7800, 7833 and 7854. a high basal-level p89 expression vector consisting of an origin-deleted lcr fused to the chloramphenicol acetyltransferase (cat) gene was utilized to determine the role of these sp1 sites in the regulation of transcription from the bpv-1 p89 promoter. the three sp1 sites were capable of binding sp1 in vitro. ... | 1996 | 8627222 |
| activation of the endogenous p53 growth inhibitory pathway in hela cervical carcinoma cells by expression of the bovine papillomavirus e2 gene. | we previously showed that expression of the bovine papillomavirus (bpv) e2 gene results in a dramatic inhibition of the proliferation of several human cervical carcinoma cell lines, including hela cells which contain human papillomavirus (hpv) type 18 dna. we have assessed the status of endogenous g1 cell cycle regulatory proteins, including the tumor suppressor proteins, p53 and p105rb, in order to investigate growth regulatory pathways in hela cells following e2 expression. the p53 tumor suppr ... | 1996 | 8632901 |
| status and transcriptional activity of a bovine-papillomavirus-i-based expression vector in a recombinant production cell lines. | | 1996 | 8639276 |
| e5 oncoprotein transmembrane mutants dissociate fibroblast transforming activity from 16-kilodalton protein binding and platelet-derived growth factor receptor binding and phosphorylation. | the e5 oncoprotein of bovine papillomavirus type 1 is a 44-amino-acid, hydrophobic polypeptide which localizes predominantly in golgi membranes and appears to transform cells through the activation of tyrosine kinase growth factor receptors. in fibroblasts, e5 interacts with both the 16-kilodalton vacuolar atpase subunit and the platelet-derived growth factor receptor (pdgf-r) via its hydrophobic transmembrane domain and induces autophosphorylation of the receptor. to further analyze the correla ... | 1996 | 8642670 |
| the human t-cell leukemia/lymphotropic virus type 1 p12i proteins bind the interleukin-2 receptor beta and gammac chains and affects their expression on the cell surface. | p12i is a small hydrophobic protein encoded by the human t-cell leukemia/lymphotropic virus type 1 (htlv-1) that interacts with the 16-kda component of the h+ vacuolar atpase and cooperates with bovine papillomavirus 1 e5 oncoprotein in cell transformation. just as an important step in e5 action appears to be its binding to the platelet-derived growth factor receptor, it was found that p12i binds specifically to both the beta and gamma(c) chains of the interleukin-2 receptor (il-2r). the il-2r b ... | 1996 | 8648694 |
| solution structure of the dna-binding domain of a human papillomavirus e2 protein: evidence for flexible dna-binding regions. | the three-dimensional structure of the dna-binding domain of the e2 protein from human papillomavirus-31 was determined by using multidimensional heteronuclear nuclear magnetic resonance (nmr) spectroscopy. a total of 1429 nmr-derived distance and dihedral angle restraints were obtained for each of the 83-residue subunits of this symmetric dimer. the average root mean square deviations of 20 structures calculated using a distance geometry-simulated annealing protocol are 0.59 and 0.90 angstroms ... | 1996 | 8652551 |
| conserved features in papillomavirus and polyomavirus capsids. | capsids of papilloma and polyoma viruses (papovavirus family) are composed of 72 pentameric capsomeres arranged on a skewed icosahedral lattice (triangulation number of seven, t = 7). cottontail rabbit papillomavirus (crpv) was reported previously to be a t = 7laevo (left-handed) structure, whereas human wart virus, simian virus 40, and murine polyomavirus were shown to be t = 7dextro (right-handed). the crpv structure determined by cryoelectron microscopy and image reconstruction was similar to ... | 1996 | 8656427 |
| genetic analysis of the bovine papillomavirus e2 transcriptional activation domain. | the bovine papillomavirus type 1 e2 transactivator has a large amino-terminal 215-residue transcriptional activation domain (tad) that is active in saccharomyces cerevisiae and higher eukaryotic cells. comparison to other transcriptional activators suggests that its functions may be mediated in part through two acidic regions, a1 and a2, in this domain. we have characterized the functional elements within the e2 tad using lexa-e2 fusions and by screening randomly generated libraries of e2 mutati ... | 1996 | 8661412 |
| the transactivation and dna binding domains of the bpv-1 e2 protein have different roles in cooperative origin binding with the e1 protein. | the bovine papillomavirus e2 transactivator protein enhances the ability of the e1 protein to bind to the viral origin of replication which contains an e1 binding site flanked by two e2 binding sites. to determine which regions and functions of the e2 protein are important for this cooperative interaction, a series of mutated e2 proteins were assayed for their ability to enhance e1 origin-specific binding. cooperative origin binding required at least one e2 dna binding site, an intact functional ... | 1996 | 8661413 |
| swelling and ca2+-activated anion conductances in c127 epithelial cells expressing wt and delta f508-cftr. | cftr is a chloride channel that is required for fluid secretion and salt absorption in many exocrine epithelia. mutations in cftr cause cystic fibrosis. cftr expression influences some ion channels, but the range of channels influenced, the mechanism of the interaction and the significance for cystic fibrosis are not known. possible interactions between cftr and other ion channels were studied in c127 mouse mammary epithelial cell lines stably transfected with cftr, delta f508-cftr, or vector. c ... | 1996 | 8661514 |
| [specific serologic studies with a novel authentic hpv antigen (virus-like particles) for hpv-6 antibodies in gynecologic patient samples]. | a serological assay for genital hpv infection would provide important additional information to hpv dna diagnostic methods, since it would evaluate prior exposure to the viruses, detect significant systemic immunologic response to virus infection, and could be performed in most clinical laboratories. | 1995 | 8672922 |
| genetic analysis of the activation domain of bovine papillomavirus protein e2: its role in transcription and replication. | the bovine papillomavirus protein e2 serves dual functions in viral transcription and in the initiation of viral replication. as a transcription factor, e2 can cooperatively interact with cellular proteins such as sp1 and stimulate transcription of distal promoters. in replication, e2 and the helicase el are the only viral proteins required for accurate replication of templates containing the viral origin. the amino terminus of e2 is a functionally separable domain critical for activation of bot ... | 1996 | 8676438 |
| selection of the bovine papillomavirus type 1 nucleotide 3225 3' splice site is regulated through an exonic splicing enhancer and its juxtaposed exonic splicing suppressor. | alternative splicing is an important mechanism for the regulation of bovine papillomavirus type 1 (bpv-1) gene expression during the virus life cycle. however, one 3' splice site, located at nucleotide (nt) 3225, is used for the processing of most bpv-1 pre-mrnas in bpv-1-transformed c127 cells and at early to intermediate times in productively infected warts. at late stages of the viral life cycle, an alternative 3' splice site at nt 3605 is used for the processing of the late pre-mrna. in this ... | 1996 | 8676495 |
| simple procedure for creation of in-frame deletion mutations throughout an open reading frame. | a general method is presented for randomly mutagenizing open reading frames (orf) to generate in-frame deletions and insertions. the protocol requires expression of the orf of interest as a hybrid orf-beta-galactosidase fusion protein. this allows colorimetric screening for beta-galactosidase activity during subsequent mutagenesis steps. consequently, proteins with no suitable phenotypic selection or screening properties can be readily screened for mutations that disrupt and subsequently restore ... | 1996 | 8679203 |
| transgenic models for papillomavirus-associated multistep carcinogenesis. | to investigate the physiological and pathological in vivo functions of molecularly cloned genes, the transgenic mouse is one of the most useful experimental animal systems. many kinds of transgenic mice carrying papillomavirus genes have been produced, and the studies have revealed several new aspects in the field of papillomaviral oncology. among these transgenic mice, the mechanism of skin carcinogenis in the bovine papillomavirus (bpv) transgenic mouse has been well characterized, demonstrati ... | 1995 | 8682614 |
| in vitro generation and type-specific neutralization of a human papillomavirus type 16 virion pseudotype. | we report a system for generating infectious papillomaviruses in vitro that facilitates the analysis of papillomavirus assembly, infectivity, and serologic relatedness. cultured hamster bphe-1 cells harboring autonomously replicating bovine papillomavirus type 1 (bpv1) genomes were infected with recombinant semliki forest viruses that express the structural proteins of bpv1. when plated on c127 cells, extracts from cells expressing l1 and l2 together induced numerous transformed foci that could ... | 1996 | 8709207 |
| transcriptional and replicational activation functions in the bovine papillomavirus type 1 e2 protein are encoded by different structural determinants. | a set of e2 proteins with mutations in the amino-terminal transactivation domain was made by a scheme called clustered charged-to-alanine scan. these mutant e2 proteins were tested for expression, stability, and compartmentalization in cells and for sequence-specific dna binding, as well as in functional assays for transcriptional and replicational activation. we identified four groups of mutants. first, mutants k111a, k112a, and e176a were unable to activate replication and transcription becaus ... | 1996 | 8709243 |
| bovine papillomavirus type 4 dna isolated from a skin lesion in a steer. | a lesion on the head of a steer, defined histologically as an epithelial papilloma, yielded dna which did not hybridise with any of the bovine papillomavirus dnas usually associated with the formation of skin lesions. dna from the lesion did hybridise with dna from bovine papillomavirus 4, even under stringent conditions, and contained a sequence that could be amplified by polymerase chain reaction with primers specific for that virus. bovine papillomavirus 4 had previously been isolated only fr ... | 1996 | 8733180 |
| vaccination of cattle with bovine papillomavirus type 4 l2 elicits the production of virus-neutralizing antibodies. | prophylactic vaccination of cattle with the n terminus (l2a, aa 11-200) of the minor capsid protein l2 completely prevented bovine papillomavirus type 4 (bpv-4) infection of the alimentary canal. to investigate the mechanisms underlying protection from viral infection, sera from vaccinated animals were analysed in neutralization assays both in the nude mouse xenograft system and in cattle. bpv-4 retained its infectivity when incubated with preimmune cattle sera, whereas, when incubated with immu ... | 1996 | 8758002 |
| characterization of the single-strand-specific bpv-1 origin binding protein, spsf i, as the hela pur alpha factor. | spsf i and ii are two cellular proteins which bind specifically to single-stranded dna. spsf i and ii binding sites are found in the minimal origin of replication of bpv-1 dna and near the p2 promoter of the cellular c-myc gene. dna-binding properties of the two proteins to single-stranded oligonucleotides of different lengths and sequences were quantified by determination of dna-binding constants. the binding constant of spsf proteins to the lower strand of the bpv-1 origin was determined to be ... | 1996 | 8759014 |
| transcriptional activation function is not required for stimulation of dna replication by bovine papillomavirus type 1 e2. | bovine papillomavirus type 1 replication was previously shown to require both the e1 initiator protein and the e2 transactivator protein. we show here that e1, in the absence of e2, is sufficient for low-level bovine papillomavirus type 1 dna replication in c-33a cells. in addition, studies of genetically isolated e2 point mutants demonstrate that enhancement of replication by e2 does not require its transcriptional activation function. the uncoupling of the e2 functions suggests that stimulatio ... | 1996 | 8794380 |
| surface conformational and linear epitopes on hpv-16 and hpv-18 l1 virus-like particles as defined by monoclonal antibodies. | a panel of 24 monoclonal antibodies (mabs) was generated against human papillomavirus (hpv) types 16 and 18 l1 virus-like particles (vlps). the mabs were screened for reactivity to a variety of vlps prepared from hpv-6, -11, -16, -18, -31, -33, -35, and -45, cottontail rabbit papillomavirus, bovine papillomavirus type 1, and a set of 35 overlapping 20-amino-acid peptides spanning the entire hpv-16 l1 gene. type-specific linear and conformational surface epitopes were detected as well as several ... | 1996 | 8806551 |
| carboxyl terminus of bovine papillomavirus type-1 l1 protein is not required for capsid formation. | the papillomavirus major capsid protein l1 can assemble into capsids in vitro. to identify areas within the bovine papillomavirus type-1 l1 (bpv l1) protein that are important for virus assembly, we constructed a set of 24 baculovirus recombinants expressing bpv l1 deletion mutants that span the entire l1 open reading frame. virus-like particle (vlp) formation of the l1 mutants was examined by electron microscopy. wild-type (wt) bpv l1 expressed in recombinant baculovirus formed vlps, while caps ... | 1996 | 8806558 |
| serologic association between human papillomavirus type 16 infection and esophageal cancer in shaanxi province, china. | the existence of large geographic variations in the prevalence of esophageal cancer in some countries, such as china, indicates that environmental risk factors may be important in the development of this disease. some studies have implicated genital-mucosal strains of human papillomaviruses (hpvs) in the etiology of this cancer. | 1996 | 8841021 |
| the atp-binding and atpase activities of human papillomavirus type 16 e1 are significantly weakened by the absence of prolines in its atp-binding domain. | the e1 protein of human papillomavirus (hpv) type 16 is the only known papillomavirus e1 which does not contain any proline residues in the phosphate-loop (p-loop) of its atp-binding site. to ascertain whether this feature influences the activities of hpv-16 e1, we generated a mutant hpv-16 e1 (e1pro) in which prolines are inserted in place of alanines in this site, making the p-loop identical to its bovine papillomavirus type 1 counterpart. glutathione s-transferase (gst) fusion proteins (gste1 ... | 1995 | 8847499 |
| different arrangement of human papillomavirus e2 binding sites distinguishes cutaneous types from those associated with mucosal lesions. | high-risk-type human papillomavirus dna sequences are found in a high percentage of carcinomas from the uterine-cervix, with the viral e1-e2 gene region usually disrupted and the e6 and e7 oncoproteins consistently expressed. the e2 protein is known to repress early transcription from genital hpv promoters having a proximal e2 binding site (e2bs) close to the tata box. on the contrary, the e2 protein activates cutaneous early promoters having a longer distance between these sites. using an in vi ... | 1996 | 8854400 |