Publications

papillomavirus infection of aged persian cats.	papillomavirus infection was confirmed in 2 persian cats with sessile hyperkeratotic skin lesions. skin lesions were not typical papillomas as found in other species. papillomavirus were demonstrated in negative stain preparations of homogenized tissue and within nuclei of cells in the stratum granulosum. papillomavirus group-specific antigens were detected within nuclei corresponding to those containing virions. attempts to transmit this disease to other cats or propagate the virus in tissue cu ...	1990	1965634
bovine papillomavirus e2 repressor mutant displays a high-copy-number phenotype and enhanced transforming activity.	the methionine codon at bovine papillomavirus type 1 nucleotide 3091 was mutated to determine whether it may serve as an initiation codon for an e2 transcriptional repressor protein and to determine the role of the repressor in the biological activities of the virus. a series of transient expression experiments with cv1 cells documented that the mutation reduced expression of repressor activity from the viral genome and resulted in increased expression of the e5 transforming gene. viral genomes ...	1990	2153255
phenotypic analysis of bovine papillomavirus type 1 e2 repressor mutants.	the bovine papillomavirus type 1 (bpv-1) e2 open reading frame encodes three proteins: the e2 transcriptional transactivator, the e2 transcriptional repressor (e2-tr), and the e8/e2 fusion peptide. in this study, we describe the phenotypes of bpv-1 mutants which are disrupted in their capacity to encode either the e2 transcriptional repressor or the e8/e2 fusion peptide. we also describe experiments which demonstrate that the e8/e2 gene product functions similarly to e2-tr. in the context of the ...	1990	2153256
generation of cell-mediated cytotoxicity against bovine-papilloma-virus-transformed primary mouse cell lines.	the immunogenicity and immunosensitivity of primary mouse cell lines transformed by bovine papilloma virus 1 (bpv1) dna were studied in a syngeneic mouse model by determining cell-mediated cytotoxicity in the spleens of mice immunized with the transformed cells. one of the cell lines induced the generation of cell-line-specific thy1.2-positive cytotoxic effector cells. however, most of the cell lines tested induced the generation of thy1.2-positive effector cells, which in addition to bpv1-trans ...	1990	2154331
the dna-binding domain of hpv-16 e2 protein interaction with the viral enhancer: protein-induced dna bending and role of the nonconserved core sequence in binding site affinity.	we expressed the carboxy-terminal portion of the e2 open reading frame (orf)-encoded protein of human papillomavirus type 16 (hpv-16) and purified it to near homogeneity. using dnase i footprinting techniques, we show that like the homologous protein from bovine papillomavirus type 1 (bpv-1), hpv-18, hpv-11, it binds dna at the enhancer consensus motif accn6ggt. base and phosphate backbone contact points were determined using methylation protection and interference and ethylation interference as ...	1990	2154890
the e2 trans-activator can act as a repressor by interfering with a cellular transcription factor.	the e2 open reading frame (orf) of the bovine papillomavirus (bpv-1) encodes a family of site-specific dna-binding proteins. the full-length protein is a transcriptional activator, whereas the polypeptides that contain only the carboxy-terminal domain are repressors. here we show that the trans-activator can work as a repressor of transcription for one of the bpv-1 promoters by binding to a dna sequence required for basal activity of the promoter. this operator site is defined as a 12-bp sequenc ...	1990	2155158
sensitization of transformed rat cells to parvovirus mvmp is restricted to specific oncogenes.	the rat cell line fr3t3 was transformed with the retroviral oncogenes v-myc or v-src, with the dna tumor viruses sv40 or bovine papilloma virus strain 1 (bpv-1) or with the 69% transforming region of bpv-1. the transformants were compared with the uncloned parental line for their susceptibility to the lytic effect and to the replication of mvmp, an autonomous parvovirus. expression of v-myc and v-src proteins and of sv40 large t antigen correlated with a greater cell susceptibility to mvmp-induc ...	1990	2157178
serological responses to papillomavirus group-specific antigens in women with neoplasia of the cervix uteri.	certain types of human papillomaviruses have been linked to the development of carcinoma of the cervix uteri. we have analyzed 114 serum specimens from women with cervical intraepithelial neoplasia (cin) or carcinoma of the cervix uteri for the presence of serum antibodies against purified, disrupted bovine papillomavirus (bpv). the titers of immunoglobulin a (iga) antibodies against bpv were slightly elevated (p less than 0.025) in the sera from cin or cervical carcinoma patients compared with ...	1990	2157738
integrated hpv 1 genomes in a human keratinocyte cell line can be transactivated by a sv40/bpv1 recombinant virus which expresses bpv1 e2 proteins.	this paper describes studies carried out on an hpv 1 carrying human keratinocyte cell line (svd2) and two subclones of it. although these lines contain multiple copies of hpv 1 genomes, in situ hybridization revealed that integration was restricted to band q33 on the long arms of chromosome 2. an e4 1.25-kb mrna was specifically identified by northern blotting and a pcr generated cdna confirmed the presence of the e1/e4 spliced mrna which is abundant in hpv 1 containing papillomas. infection of ...	1990	2158183
mutational analysis of cis elements involved in e2 modulation of human papillomavirus type 16 p97 and type 18 p105 promoters.	cis-acting elements involved in e2 modulation of human papillomavirus type 16 (hpv-16) p97 promoter activity and hpv-18 p105 promoter activity were examined. in transfected primary human keratinocytes, each promoter had a basal activity that could be repressed by the bovine papillomavirus type 1 e2 gene product. mutational analysis of the e2-binding sites in the long control region upstream of each promoter revealed that e2 repression was mediated through the e2-binding sites proximal to each pr ...	1990	2159546
a bovine papillomavirus type-1 (bpv-1) containing plasmid replicates extrachromosomally in xenopus embryos.		1990	2159642
tumorigenicity and h-2 expression of papillomavirus-transformed mouse cell lines.	tumorigenicity in immunocompetent syngeneic mice and h-2 class i antigen expression of bpv1-transformed mouse cell lines had no correlation. h-2 expression was examined using monoclonal anti-(h-2kb) and anti-(h-2db) antibodies in immunofluorescence staining for flow cytometry analysis and by determining the sensitivity of the cells to cytolysis by allostimulated spleen cells. nontumorigenic cell lines were as resistant as tumorigenic cell lines to natural killer activity. the results indicate th ...	1990	2159847
glucocorticoid receptor-dependent disruption of a specific nucleosome on the mouse mammary tumor virus promoter is prevented by sodium butyrate.	our laboratory has previously developed cell lines derived from mouse nih 3t3 fibroblasts and c127 mammary tumor cells that stably express mouse mammary tumor virus (mmtv) long terminal repeat fusion genes in bovine papillomavirus-based episomes. glucocorticoid hormone strongly activates transcription from episomes and induces the disruption of a single nucleosome in an array of phased nucleosomes on the mmtv promoter. sodium butyrate inhibits the glucocorticoid hormone-dependent development of ...	1990	2160080
transforming growth factor-beta expression in fibropapillomas induced by bovine papillomavirus type 1, in normal bovine skin, and in bpv-1-transformed cells.	there is substantial evidence to suggest that transforming growth factor-beta (tgf-beta) plays an important role in wound healing and tissue repair as well as in carcinogenesis. it has also been observed that naturally occurring bovine papillomavirus type 1 (bpv-1)-induced bovine fibropapillomas occur predominantly at traumatized sites of the body, suggesting that humoral factors released in wounds might be important for papillomavirus infection. we have therefore investigated the possible role ...	1990	2160257
evidence that replication initiates at only some of the potential origins in each oligomeric form of bovine papillomavirus type 1 dna.	in a subclone of id13 mouse fibroblasts latently infected with bovine papillomavirus type 1 (bpv-1) dna, the viral genome occurred as a mixture of extrachromosomal circular monomers and oligomers. multiple copies were also associated with the host cell genome, predominantly at a single site in a head-to-tail tandem array. we examined the replicative intermediates of extrachromosomal forms of bpv-1 dna by using two-dimensional gel electrophoresis. the results obtained indicate that initiation of ...	1990	2160593
transcriptional activation by the papillomavirus e6 zinc finger oncoprotein.	the introduction of the bovine (bpv) or human papillomavirus e6 gene into susceptible cells can result in their transformation, but there are few clues to the mechanism of action of the e6 gene. the characteristic features of e6 proteins are their small size (approximately 150 amino acids) and the potential to form two large zinc fingers. to determine if e6 can function as a transcription factor, the bpv e6 gene was fused to the sequence specific dna binding peptide encoded by the bpv e2 gene. t ...	1990	2161335
optimization of the hygromycin b resistance-conferring gene as a dominant selectable marker in mammalian cells.	the hyr gene, conferring resistance to hygromycin b (hy), has been modified for optimal expression in mammalian cells. modifications to the hyr gene and its expression cassette include: (1) removal of all upstream start codons, (2) conversion of the region around the start codon to the consensus sequence associated with efficient translation initiation, and (3) removal of downstream splice donor and acceptor sequences. the resulting hyr gene is an efficient dominant selectable marker that is use ...	1990	2161383
studies on vaccination against papillomaviruses: the immunity after infection and vaccination with bovine papillomaviruses of different types.	calves, free of antibodies to bovine papillomaviruses (bpv), were reared in isolation. one was infected with bpv-2, developed tumours and was resistant to homologous reinfection. groups of calves were infected with bpv-2, bpv-5 or bpv-6; they all developed and subsequently rejected type-specific tumours. they were then infected with bpv-4; they were not immune and oral papillomas were induced. groups of animals were vaccinated by intramuscular preparations of purified bpv-4 and bpv-6 and were ch ...	1990	2161579
studies on vaccination against papillomaviruses: a comparison of purified virus, tumour extract and transformed cells in prophylactic vaccination.	calves were vaccinated with two preparations made from one cutaneous fibropapilloma induced by bovine papillomavirus type 2 (bpv-2). one vaccine consisted of homogenised tumour; the other contained purified virus only. both produced resistance to a heavy challenge infection of bpv-2. one calf in the vaccinated group developed a small tumour and rejected it earlier than the control calves. it would appear likely that the prophylactic immune response was induced by viral structural proteins only a ...	1990	2162579
vaccinia recombinants expressing early bovine papilloma virus (bpv1) proteins: retardation of bpv1 tumour development.	papillomaviruses are aetiological agents of epithelial proliferative diseases in animals and in man. it was previously demonstrated that animals inoculated with live vaccinia recombinants expressing early proteins of polyoma virus resist challenge with polyoma-tumour cells, and this approach has been extended to the development of a vaccine against papillomavirus-transformed cells. bovine papillomavirus type 1 (bpv1), a virus responsible for dermal lesions in cattle, is a prototype virus of the ...	1990	2163573
histopathological development of equine cutaneous papillomas.	the histopathological development of equine cutaneous papillomas was studied in 78 warts naturally occurring in 50 one to 3-year-old thoroughbred or arab horses and in 54 warts experimentally induced in three 2-year-old thoroughbreds. lesions in the natural cases were categorized into three phases, growth, development and regression. main lesions of the growing phase were marked hyperplasia of the basal cells and mild to moderate acanthosis, hyper- and parakeratosis with a few intranuclear inclu ...	1990	2164051
the e2 transactivator of bovine papillomavirus type 1 is expressed from multiple promoters.	the e2 proteins of bovine papillomavirus type 1 (bpv-1) are a family of site-specific dna-binding proteins which regulate viral transcription by repression and activation. repressors e2-tr and e8/e2 are expressed from promoters p5 (p3080) and p3 (p890), respectively. previous reports have provided evidence that the transcript for the 48-kilodalton transactivator is initiated from a promoter proximal to the open reading frame encoding this protein (p2440 or p4). our studies extend these findings ...	1990	2164604
cooperative activation of transcription by bovine papillomavirus type 1 e2 can occur over a large distance.	the viral transcriptional factors encoded by the e2 open reading frame bind to the specific dna sequence elements accgnnnncggt, allowing activation or repression of transcription. we have analyzed bovine papillomavirus type 1 e2 transactivation using recombinant genes containing e2-binding sites inserted at either 3' or 5' positions relative to the heterologous transcriptional initiation site of the herpes simplex virus thymidine kinase gene. in these hybrid plasmids, strong transactivation requ ...	1990	2164642
the effect of retinoids, carotenoids and phenolics on chromosomal instability of bovine papillomavirus dna-carrying cells.	antioxidants were found to protect against the genotoxic effects of chemical and physical mutagenic and clastogenic agents. this study focused on the capacity of antioxidants to reduce an intrinsic and persistent chromosome instability. as a model system, strains of c127 cells, which were transformed by bovine papillomavirus (bpv) dna and which carry bpv dna varying from 20 to 160 copies, were used. transformed cells of 10 different strains showed a persistently high incidence of mitotic irregul ...	1990	2165562
implantation of genetically manipulated fibroblasts into mice as antitumor alpha-interferon therapy.	long-term parenteral administration of human alpha-interferon (huifn-alpha) is effective in the treatment of several malignancies, including chronic myelocytic leukemia. in the present study, a model for fibroblast-mediated huifn-alpha gene therapy for the treatment of chronic myelocytic leukemia is described. human ifn-alpha 5 complementary dna was inserted into a bovine papilloma virus plasmid vector (bmgneo) containing a neomycin resistance gene. the recombinant plasmid (bmgneo-ifn) was trans ...	1990	2165855
saturation mutagenesis using mixed oligonucleotides and m13 templates containing uracil.		1990	2166223
human papillomavirus infection of the uterine cervix analyzed by nonisotopic in situ hybridization.	some types of human papillomaviruses (hpvs) have been suggested to be strongly related to uterine cervical carcinoma. an attempt to detect these in formalin-fixed, paraffin-embedded sections was made by either immunohistochemical or by in situ hybridization. anticapsid protein of bovine papillomavirus antibody labeled with peroxidase was used for immunohistochemistry, and biotin was used instead of radioisotopes to label probes for in situ hybridization, which resulted in low background and a ra ...	1990	2167347
papillomavirus trans-activator protein e2 activates expression from the promoter for the ribonucleotide reductase large subunit from herpes simplex virus type 2.	activation of the herpes simplex virus type 2 (hsv-2) large subunit of the ribonucleotide reductase (icp10) gene by papillomavirus dna encoding the e2 or e7 proteins was studied directly by immunofluorescence or by chloramphenicol acetyltransferase (cat) analysis with hybrid icp10 or ie175 and 38k promoter constructions. cotransfection with bovine papillomavirus type 1 or human papillomavirus type 16 (hpv-16) e2 dna enhanced cat expression from constructions in which cat is regulated by the icp1 ...	1990	2167936
identification of a 68-kilodalton nuclear atp-binding phosphoprotein encoded by bovine papillomavirus type 1.	e1 is the largest open reading frame (orf) of bovine papillomavirus type 1 (bpv-1) and is highly conserved among all papillomaviruses, maintaining its size, amino acid composition, and location in the viral genome with respect to other early genes. multiple viral replication functions have been mapped to the e1 orf of bpv-1, and evidence suggested that more than one protein was encoded by this orf. we previously identified a small protein (m) whose gene consists of two exons, one encoded by the ...	1990	2168988
topoisomerase ii-mediated dna damage of episomes in tumor-bearing mice.	observations of cells in culture have demonstrated that, for many antitumor agents, topoisomerase ii-mediated dna damage relates to cytotoxicity. however, there is no evidence in tumor-bearing animals to suggest that such agents induce topoisomerase ii-mediated damage of dna in solid tumors or that such damage reflects inhibition of tumor growth. to address this question, a mouse fibroblast cell line neoplastically transformed by an episomal element containing the v-ha-ras and bovine papillomavi ...	1990	2169334
therapeutic value of partial excision of lesions combined with administration of an autogenous vaccine during an episode of cutaneous papillomatosis in cattle of uganda.	the therapeutic value of partial excision of lesions combined with administration of an autogenous vaccine in calves during an episode of cutaneous papillomatosis was evaluated. of 10 holstein calves naturally infected with cutaneous papillomatosis, 5 were given 20 ml of autogenous vaccine in addition to undergoing partial excision of the lesions; the other 5 calves were not given vaccine. results indicate that partial excision combined with administration of autogenous vaccine has some therapeu ...	1990	2170314
a bovine papillomavirus constitutive enhancer is negatively regulated by the e2 repressor through competitive binding for a cellular factor.	the bovine papillomavirus type 1 long control region (lcr) contains dna sequence elements involved in the regulation of viral transcription and replication. differences in the levels of transcription have previously been noted between bovine papillomavirus type 1-infected rodent cell lines and bovine cells. to investigate these differences, fragments of the lcr were cloned into an enhancer-deleted chloramphenicol acetyltransferase expression vector and assayed for enhancer activity. a strong con ...	1990	2170679
induction of bovine papillomavirus e2 gene expression and early region transcription by cell growth arrest: correlation with viral dna amplification and evidence for differential promoter induction.	the bovine papillomavirus type 1 (bpv-1) genome replicates as a latent plasmid in mouse c127 cells transformed in vitro by the virus. however, we have recently shown that bpv-1 dna amplification can be induced in a subpopulation of cells under culture conditions which suppress cell proliferation, a finding which led us to hypothesize that expression of a viral replication factor was regulated by cell growth stage. in this report, we describe the detection in these cells of abundant bpv-1 nuclear ...	1990	2170685
the e6/e7 promoter of human papillomavirus type 16 is activated in the absence of e2 proteins by a sequence-aberrant sp1 distal element.	the e6/e7 promoter of all genital human papillomaviruses is responsible for expression of the viral transforming genes. centered 60 bp upstream of the transcription start, it contains a 20-bp segment with partially overlapping binding sites for the viral e2 proteins and for a cellular factor that was identified by footprint experiments. bandshifts, bandshift competitions, and footprints revealed that protein complexes between nuclear extracts and these sequences have binding properties indisting ...	1990	2170687
complementation of a vesicular stomatitis virus glycoprotein g mutant with wild-type protein expressed from either a bovine papilloma virus or a vaccinia virus vector system.	using a complementation assay, we have evaluated the potential of two eukaryotic expression systems to produce functional virus proteins. the first expression system was based on a bovine papilloma virus (bpv) eukaryotic expression vector which contained a copy of the gene for the membrane glycoprotein g of vesicular stomatitis virus (vsv). this vector was transfected into a mouse cell line, and transformed cell clones constitutively expressing vsv g protein were selected. these cell clones were ...	1990	2171187
adenovirus infection induces amplification of persistent viral dna sequences (simian virus 40, hepatitis b virus, bovine papillomavirus) in human and rodent cells.	adenoviruses, types 2 and 12 induce amplification of sv40 dna sequences in cells of the sv40-transformed human newborn kidney cell line, nb-e. similarly, integrated hepatitis b virus dna sequences in the human hepatoma cell line, plc/*prf/5, and bovine papillomavirus (bpv) dna sequences in bpv-transformed mouse cells (id13) are amplified by adenovirus infection. thus, similar to herpes group or vaccinia viruses or dna damaging agents, adenoviruses are able to mediate selective dna amplification ...	1990	2171240
production and characterization of a fragment containing the hiv-gp120 binding region of cd4 using a bovine papilloma virus (bpv) vector.	we have used a bovine papilloma virus (bpv) based mammalian cell expression vector consisting of the complete bpv genome and a human cytomegalovirus transcription unit for the production of soluble cd4. mouse c-127 cells were transfected with vector dna together with a selectable g418 resistance plasmid. surviving clones were selected for high production using a solid phase elisa based on the immobilization of supernatant-derived cd4 onto nitrocellulose paper and subsequent detection with anti-c ...	1990	2171457
replication of bovine papillomavirus type 1 dna initiates within an e2-responsive enhancer element.	when bovine papillomavirus transforms cells in vitro, it maintains its genome as a multicopy nuclear plasmid. plasmid dna extracted from such transformed cells was analyzed by the two-dimensional gel electrophoresis technique of brewer and fangman (b. brewer and w. fangman, cell 51:463-471, 1987). the replication intermediates detected in these assays were found to be the sums of the oligomeric and monomeric forms of the replicating plasmids. the multimeric dnas were shown by field inversion gel ...	1990	2173772
proteins encoded by the bovine papillomavirus e1 open reading frame: expression in heterologous systems and in virally transformed cells.	the e1 open reading frame (orf) of bovine papillomavirus type 1 is required for the persistence of viral genomes as multicopy plasmid molecules in transformed rodent fibroblasts. e1 has been reported to contain two separate complementation groups (m and r, corresponding to n- and c-terminal domains, respectively) which regulate viral replication. however, e1 behaves as a single gene with respect to cell transformation and viral transcription. we examined the proteins translated from the entire o ...	1990	2173778
local immune reaction in syngeneic mice against tumorigenic and nontumorigenic bpv-transformed mouse cell lines.	the role of cytotoxic t cells in immune response to bovine papillomavirus type 1 (bpv1)-transformed mouse cell lines was assessed. the chromium release assay was used to follow the induction of cytotoxicity in local lymph nodes of syngeneic c57bl/6j (b6) mice after injection of bpv1-transformed cell lines tumorigenic in nude mice but tumorigenic or nontumorigenic in b6 mice. the nontumorigenic cell line b6b31.c-nut.a induced cell line-specific cytotoxicity with a maximal activity on day 7 after ...	1990	2173935
non-selective analysis of the transformation of fr3t3 rat cells by bovine papillomavirus type 1: regulations of viral transcription associated with phenotypic transformation.	drug-resistant clones selected from fr3t3 rat cells after transfer of neo-bpv1 (bovine papillomavirus type 1) dna constructs became phenotypically transformed (focal transformation, growth in suspension and tumor formation) soon after selection (approximately 5 generations in culture). a frameshift mutation in orf e5 abolished transformation, but did not prevent the autonomous maintenance of the dna construct. a more complex situation was observed when the e2 transactivating function was abrogat ...	1990	2176280
targeting the e1 replication protein to the papillomavirus origin of replication by complex formation with the e2 transactivator.	the mechanism by which transcription factors stimulate dna replication in eukaryotes is unknown. bovine papillomavirus dna synthesis requires the products of the viral e1 gene and the transcriptional activator protein encoded by the e2 gene. experimental data showed that the 68-kilodalton (kd) e1 protein formed a complex with the 48-kd e2 transcription factor. this complex bound specifically to the viral origin of replication, which contains multiple binding sites for e2. repressor proteins enco ...	1990	2176744
cooperation between bovine papillomavirus type 4 and ras in the morphological transformation of primary bovine fibroblasts.	primary bovine fibroblasts derived from foetal palate can be transformed by bovine papillomavirus type 4 dna only in the presence of an activated ras gene, indicating that the virus does not encode all the information required for morphological transformation of non-established cells. a subgenomic fragment containing the complete e8 and e7 open reading frames (orfs) induces transformation in cooperation with activated ras but transformation is abolished when the e7 orf is deleted at the 3' end, ...	1990	2177095
homologous recombination in a mammalian plasmid.	bovine papillomavirus (bpv) shuttle vectors replicate as a circular plasmid in mouse cell nuclei without impairing host cell viability. we used these vectors to analyze homologous recombination in mammalian cells. when several bpv-based plasmids carrying direct repeats were introduced into c127 cells, we detected many recombinant plasmid molecules that have lost the sequence between the repeats. many recombinant type molecules as well as parental type molecules were detected in all the cell clon ...	1990	2177135
bovine serological response to a recombinant bpv-1 major capsid protein vaccine.	four of five groups of holestine by angus calves (5 calves/group) were immunized with different formulations of a recombinant bpv-1 dna vaccine using a bpv-1 major capsid:b-galactosidase fusion protein as the immunogen. group 5 was not vaccinated. vaccinated calves received the vaccine on days 0 and 21 of the trial, and calves from all five groups were challenged intradermally with 10(10) bpv-1 particles at each of two different sites on day 56. all calves were bled on days 3, 24, 55, 77, and 10 ...	1990	2177743
detection of papillomavirus dna in precancerous lesions of the ears of sheep.	sixty-seven benign precancerous cutaneous lesions from the ears of 51 sheep were examined for papillomavirus dna by hybridisation to radioactively labelled or biotinylated probes of bovine papillomavirus type 1 (bpv 1) dna under varying conditions of stringency. an additional 16 precancerous lesions from other cutaneous sites on 15 sheep and 15 samples of lesion-free skin from nine sheep were similarly examined. both total genomic and subgenomic probes were used. dna from 10 aural lesions and on ...	1990	2177931
studies on the transmission of viral disease via the co2 laser plume and ejecta.	while recent reports have noted the presence of viral dna sequences in the laser plume, no significant effort has been made to study transmission of the virus in vivo via airborne laser debris. studies were undertaken to identify potential hazards to operating room occupants in gynecologic laser surgery. aco2 laser in the continuous wave mode using a power density of 666 w/cm2 was fired through a 5-cm metal cylinder at virus-infected tissues. airborne particulate debris, 100-200 microns, was rem ...	1990	2178190
overexpressed human metallothionein iia gene protects chinese hamster ovary cells from killing by alkylating agents.	experiments were designed to detect survival advantages that cells gain by overexpressing metallothionein (mt). chinese hamster ovary k1-2 cells and an x-ray-sensitive derivative were transfected with a bovine papillomavirus (bpv)-linked construct carrying the human metallothionein iia (hmt-iia) gene. transfectants survived 40-fold higher levels of cadmium chloride, harbored at least 30 copies of hmt-iia, and contained 25- to 166-fold more mt than the parent cells. even under conditions of reduc ...	1990	2320583
functional analysis of e2-mediated repression of the hpv18 p105 promoter.	transcription of the transforming genes e6 and e7 of the human papillomavirus type 18 (hpv18) can be repressed by the product of the e2 open reading frame. mutations were introduced in the cis-responsive elements upstream from the e6 and e7 transcriptional promoter, p105. the effect of these mutations in the absence or presence of e2 was examined in the human cervical carcinoma cell line c33, transfected with expression plasmids. in the presence of hpv18 e2, repression was relieved only when bot ...	1991	1645591
genital bovine papillomavirus infection in saudi arabia.	genital bovine papillomavirus infection was observed for the first time in the al-ahsa region of saudi arabia. the disease involved 1 female and 2 male 2-4-year-old crossbred cattle. fibropapillomas (warts) were limited to the prepuce and vulva. electron micrographs of thin sections of the lesions revealed the presence of intranuclear viruslike particles. using a broadly cross-reactive rabbit polyclonal antiserum directed against papillomavirus group-specific antigens, the infection was confirme ...	1991	1645597
papillomavirus dna replication.		1991	1645776
bovine papillomavirus type 1 alters the processing of host glucose- and calcium-modulated endoplasmic reticulum proteins.	we have previously characterized five proteins induced by the presence of the e2 open reading frame (orf) region of bovine papillomavirus type 1 (bpv-1) in c127 mouse fibroblasts (r. m. levenson, u. g. brinckmann, m. k. o'banion, e. j. androphy, j. t. schiller, f. tabatabai, l. p. turek, k. neary, m. t. chin, t. r. broker, l. t. chow, and d. a. young, virology 172:170-179, 1989). by specific immunoprecipitation, we now find that one of the papillomavirus-associated proteins (pvp1) is a highly gl ...	1991	1645780
[papillomatosis of cattle and its relationship to equine sarcoid].	the aetiology and the pathogenesis of equine sarcoids are described. aspects of therapy are discussed.	1991	1646494
topological properties of bovine papillomavirus type 1 (bpv-1) dna in episomal nucleoprotein complexes: a model system for chromatin organization in higher eukaryotes.	sedimentation analysis of isolated episomal bovine papillomavirus type 1 (bpv-1) nucleoprotein complexes in sucrose gradients and subsequent separation of the purified dna in chloroquine gels revealed different classes of molecules, varying in their degree of superhelicity. since torsionally stressed dna favors the adoption of secondary structures, we employed the single-strand-specific s1 nuclease to detect such structural alterations in both naked dna and native chromatin. direct examination o ...	1991	1648363
formation of the complex of bovine papillomavirus e1 and e2 proteins is modulated by e2 phosphorylation and depends upon sequences within the carboxyl terminus of e1.	the 68-kda bovine papillomavirus (bpv) type 1 replication protein e1 and the 48-kda transactivator protein e2 form a complex that specifically binds dna [mohr, i.j., clark, r., sun, s., androphy, e.j., macpherson, p. & botchan, m.r. (1990) science 250, 1694-1699]. we have confirmed this observation and shown that the e1-e2 complex binds to dna fragments that contain the bpv plasmid maintenance sequence 1 and a site for the initiation of bidirectional bpv dna synthesis. the e1 protein was found t ...	1991	1648739
bovine papillomavirus e5 oncoprotein binds to the 16k component of vacuolar h(+)-atpases.	the major transforming protein of bovine papillomavirus type 1, e5, is mainly associated with endomembranes, specifically binding to a cellular protein of relative molecular mass 16,000 (16k). at the same time as transformation, e5 causes the phosphorylation of tyrosine residues in epidermal and platelet-derived growth factor receptors. we show here that the 16k protein associated with e5 is the 16k component of vacuolar atpases. this protein is known to be an integral membrane protein in endoso ...	1991	1649407
expression of epidermal growth factor precursor cdna in animal cells.	this chapter outlines in detail the optimal conditions for the expression of human recombinant proteins in mouse cells using a bovine papillomavirus-based mammalian expression vector. the procedures we have described were used to successfully express high levels of the human egf precursor in our laboratory and the human insulin receptor in the laboratory of whittaker. using this experimental approach we were able to demonstrate that expression of a cdna for prepro-egf produces a glycosylated mem ...	1991	1649948
in vitro "progression" of bovine papillomavirus-transformed cells: loss of contact sensitivity after multiple rounds of selection.	the transformed phenotype of c127 cells harboring bovine papillomavirus shuttle vector pdbpvmmt neo(342-12) was suppressed by direct contact with untransformed c127 cells. by repeated selections of rare foci developing on untransformed cell monolayers, we obtained a cellular clone of bpv transformants which formed foci on the untransformed c127 cells as efficiently as on plastic surface. the bpv genome in the mutant cells showed extensive genetic rearrangements, duplication of upstream regulator ...	1991	1650331
characterization of bpv-like dna in equine sarcoids.	the dna from equine sarcoid samples from new york state and switzerland was isolated and probed with bovine papillomavirus type 1 (bpv-1) to determine if bpv genomes were present. twelve of 13 sarcoids from new york state and 17/20 sarcoids from switzerland contained dna that hybridized to the bpv-1 probe. restriction enzyme analysis of the positive samples demonstrated restriction fragment profiles characteristic of bpv-1 in 22 sarcoids and restriction fragment profiles characteristic of bovine ...	1991	1650553
in vitro interactions between bovine papillomavirus and human monocytes and macrophages.	limited data suggest that macrophages play a role in the pathogenesis of bovine papillomavirus (bpv) infections. in the present study, interactions between these cells and bpv-1 were explored by exposing in vitro human blood monocytes and monocyte-derived macrophages to purified virions. immediately or up to 28 days after exposure, cell culture supernatants as well as cell lysates were collected. interleukin 1 activity was detected in the supernatants of monocytes early after exposure to bpv (0- ...	1991	1650765
initiation of transcription from the minute virus of mice p4 promoter is stimulated in rat cells expressing a c-ha-ras oncogene.	transformation of fr3t3 rat fibroblasts by a c-ha-ras oncogene but not by bovine papillomavirus type 1 is associated with an increase in the abundance of mrnas from prototype strain mvmp of infecting minute virus of mice, an oncosuppressive parvovirus. this differential parvovirus gene expression correlates with the reported sensitization of ras- but not bovine papillomavirus type 1-transformed cells to the killing effect of mvmp (n. salomé, b. van hille, n. duponchel, g. meneguzzi, f. cuzin, j. ...	1991	1651412
biological properties of the deer papillomavirus e5 gene in mouse c127 cells: growth transformation, induction of dna synthesis, and activation of the platelet-derived growth factor receptor.	we determined the biological activities of the 44-amino-acid deer papillomavirus (dpv) e5 protein in mouse c127 cells. the dpv e5 gene can induce focus formation, stable and acute morphologic transformation, and dna synthesis, and it activates the platelet-derived growth factor (pdgf) beta receptor as assessed by increased constitutive tyrosine phosphorylation of mature and precursor receptor forms. thus, the dpv e5 protein has biological activities similar to those of the closely related e5 pro ...	1991	1651413
studies on vaccination against papillomaviruses: prophylactic and therapeutic vaccination with recombinant structural proteins.	the l1 and l2 proteins of bpv-2 have been produced in escherichia coli as beta-galactosidase fusion proteins. the fusion proteins have been used to vaccinate calves both prophylactically and therapeutically. the l1 fusion protein prevented tumor formation when administered before challenge with bpv-2, while the l2 fusion protein was very effective in promoting tumor rejection, independently from whether it was administered before or after challenge. animals vaccinated with l1, but not with l2, r ...	1991	1651594
[detection of bovine papillomavirus dna in equine sarcoids using the polymerase chain reaction (pcr)].	unfixed and formalin-fixed frozen sections and paraffin-sections of histopathologically confirmed sarcoids of 20 horses were studied in the pcr. the used set of primers was located in the e5 open reading frame fitting both to bovine papillomavirus 1 (bpv-1) and bpv-2. independent of the quality of the used tissues bpv-dna was detected in all 20 sarcoids. by cleaving with restriction endonuclease bst xi it was shown that the dna-sequences amplified by pcr were identical with that of bpv-1. the re ...	1991	1652932
illegitimate recombination in a bovine papillomavirus shuttle vector: a high level of site specificity.	recombination in a bovine papillomavirus shuttle vector carrying direct repeats of moloney murine leukemia virus ltr sequence was examined. differently from similar vectors carrying direct repeats of sv40 polya addition signal or neomycin resistance gene, the vector exhibited no homologous recombination between the repeats. instead, illegitimate recombination took place. there were two major types of recombination products from the restriction cleavage pattern. the plasmids in independent cellul ...	1991	1652950
two dna-bound e2 dimers are required for strong transcriptional activation and for cooperation with cellular factors in most cells.	the e2 transcriptional activator encoded by papillomaviruses binds as a dimer to the palindromic sequence accgnnnncggt present in several copies in the viral genomes. we show that strong activation requires that a minimum of two e2 binding sites are actually occupied by the protein. studies with constructs bearing two e2 sites separated by variable lengths of dna showed that there is no stereospecific constraint for e2 homosynergy. the capacity of e2 to cooperate with cellular factors interactin ...	1991	1653009
the functional bpv-1 e2 trans-activating protein can act as a repressor by preventing formation of the initiation complex.	the products encoded by the e2 open reading frame of the papillomaviruses are dna-binding transcription factors involved in the positive or negative regulation of multiple viral promoters. to further understand the mechanisms by which the same transcription factor may act differentially, the full-length bpv-1 e2 protein was expressed and purified from yeast and assayed in vitro for its capacity to modulate transcription. e2 stimulated transcription of the hsv thymidine kinase (tk) promoter when ...	1991	1653173
[implantation of genetically manipulated fibroblasts into mice as a model of gene therapy--supplementations of human granulocyte colony-stimulating factor (hg-csf) and interferon-alpha (ifn-alpha)].	implantation of genetically manipulated fibroblasts is now coming considered to be one of the important methods for gene therapy. before the clinical application of this method, we still need to resolve several problems encountered. we have recently developed a model system for the fibroblast-mediated cytokine supplementation gene therapy. bmgneo (bovine papilloma virus-derived plasmid) (gifted from dr. karasuyama) was used for expression of hg-csf cdna or hifn-alpha cdna (gifted from dr. nagata ...	1991	1653596
immunofluorescent detection of bovine papillomavirus e4 antigen in the cytoplasm of cells permissive in vitro for viral dna amplification.	the e4 gene of several human papillomavirus types is expressed in association with vegetative viral dna synthesis in differentiated epidermal cells. to develop reagents to study expression of the bovine papillomavirus type 1 (bpv-1) e4 gene in warts and in virus-transformed cell lines, rabbit polyclonal antiserum was raised to the bpv-1 e4 antigen produced as a fusion polypeptide in escherichia coli. by immunoblotting analysis of productively infected bovine fibropapilloma tissue, e4-related pro ...	1991	1654378
a bovine papillomavirus e1-related protein binds specifically to bovine papillomavirus dna.	the e1 open reading frame of bovine papillomavirus (bpv) was expressed as a reca-e1 fusion protein in escherichia coli. the bacterially expressed reca-e1 protein exhibited sequence-specific dna binding activity; strong binding to the region from nucleotides 7819 to 93 on the bpv genome (designated region a) and weak binding to the adjacent region from nucleotides 7457 to 7818 (region b) were observed. the interaction between the bpv-derived reca-e1 protein and region a appeared to be highly spec ...	1991	1654443
the b subgroup bovine papillomaviruses lack an identifiable e6 open reading frame.	analysis of the corrected dna sequence for the bovine papillomavirus type 4 (bpv4) genome revealed that there is no open reading frame (orf) that might encode an e6 protein. the other two b subgroup bovine papillomaviruses, bpv3 and bpv6, were found to have the same arrangement of orfs in this region as bpv4. thus, we conclude that e6 functions are either not required by these viruses or are performed by another viral (or host) protein. furthermore, the position that might be expected to be occu ...	1991	1654923
[comparison of vector properties of the usual and modified sequences of the bpv-1 genome].		1991	1655372
several different upstream promoter elements can potentiate transactivation by the bpv-1 e2 protein.	the enhancer and upstream promoter regions of rna polymerase ii transcribed genes modulate the rate of transcription initiation and establish specific patterns of gene expression. both types of region consist of clusters of dna binding sites for nuclear proteins. to determine how efficiently the same factor can activate transcription when acting as an enhancer or promoter factor, we have studied transactivation by the bpv-1 e2 protein, a papillomavirus transcriptional regulator. by cotransfectin ...	1991	1655407
the papillomavirus e2 regulatory proteins.		1991	1655748
sequencing data on the long control region of human papillomavirus type 16.	a one base change (adenine at position 7861) in the long control region (lcr) of the prototype sequence of human papillomavirus type 16 was reported. with this correction, a new e2-binding site was revealed, 111 bp and 143 bp upstream from the tata box and p97, respectively, and 105 bp downstream of the keratinocyte-dependent enhancer. an a to c mutation at position 41 was found in a patient with invasive carcinoma. this mutation falls within an e2-binding site.	1991	1655963
regulation of early gene expression from the bovine papillomavirus genome in transiently transfected c127 cells.	expression of bovine papillomavirus (bpv) early gene products is required for viral dna replication and establishment of the transformed phenotype. by the use of a highly efficient electroporation system, we have examined for the first time the transcriptional activity of bpv promoters in their natural genomic context in a replication-permissive cell line. we have determined that a qualitatively distinct stage of transcription is not detectable prior to dna replication in transiently transfected ...	1991	1656065
activation of bpv-1 replication in vitro by the transcription factor e2.	soluble extracts from uninfected murine cells supplemented with purified viral e1 and e2 proteins support the replication of exogenously added papilloma virus dna. the e2 transactivator stimulates the binding of the e1 replication protein to the minimal origin of replication and activates dna replication. these results support the concept that transcription factors have a direct role in the initiation of dna replication in eukaryotes by participating in the assembly of a complex at the origin of ...	1991	1656277
native yeast telomeres are sufficient to stabilize linear dna in xenopus laevis oocytes.	we have constructed a linear plasmid in yeast containing the entire bovine papillomavirus genome and tested its physical stability following microinjection into stage vi oocytes of xenopus laevis. our results show that unmodified telomeres, in contrast to the yeast-passaged telomeres, drastically affect the stability of the injected linear plasmid. plasmids carrying unmodified tetrahymena thermophila telomeric sequences are rapidly degraded in oocytes. when these plasmids are passed through yeas ...	1991	1657721
bovine papillomavirus with a mutation in the e2 serine 301 phosphorylation site replicates at a high copy number.	the e2 open reading frame of bovine papillomavirus type 1 (bpv-1) encodes at least three proteins with transcriptional regulatory properties. the full-length e2 open reading frame encodes a transcriptional transactivator, and the 3' region encodes two smaller polypeptides that repress e2-mediated transactivation. the full-length gene product is also required for viral dna replication. we have demonstrated that the bpv-1 e2 polypeptides are phosphorylated primarily on two serine residues at a sit ...	1991	1658358
tumorigenic transformation of murine keratinocytes by the e5 genes of bovine papillomavirus type 1 and human papillomavirus type 16.	to examine the biological properties of the bovine papillomavirus type 1 (bpv) and human papillomavirus type 16 (hpv16) e5 genes, each was cloned separately into a retroviral expression vector and helper-free recombinant viruses were generated in packaging cell lines. the bpv e5 retroviruses efficiently caused morphologic and tumorigenic transformation of cultured lines of murine fibroblasts, whereas the hpv16 e5 viruses were inactive in these assays. in contrast, infection of the p117 establish ...	1991	1658398
the bovine papillomavirus e5 oncogene can cooperate with ras: identification of p21 amino acids critical for transformation by c-rash but not v-rash.	we have previously used a series of insertion-deletion mutants of the mutationally activated v-rash gene to identify several regions of the encoded protein that are dispensable for cellular transformation (b. m. willumsen, a. g. papageorge, h.-f. kung, e. bekesi, t. robins, m. johnsen, w. c. vass, and d. r. lowy, mol. cell. biol. 6:2646-2654, 1986). to determine if some of these amino acids are more important for the biological activity of c-rash, we have now tested many of the same insertion-de ...	1991	1658623
efficient selection for high-expression transfectants with a novel eukaryotic vector.	we have developed a new expression vector which allows efficient selection for transfectants that express foreign genes at high levels. the vector is composed of a ubiquitously strong promoter based on the beta-actin promoter, a 69% subregion of the bovine papilloma virus genome, and a mutant neomycin phosphotransferase ii-encoding gene driven by a weak promoter, which confers only marginal resistance to g418. thus, high concentrations of g418 (approx. 800 micrograms/ml) effectively select for t ...	1991	1660837
cell transformation induced by bovine papillomavirus dna as an assay for tumor promoters and chemopreventive agents.	an in vitro assay was designed to examine and quantitate the action of chemical promoters and chemopreventive agents on papillomavirus dna-carrying cells. cultured c3h/10t1/2 cells transfected with bovine papillomavirus type 1 dna (plasmid pdbpv-1) were used as targets, and the frequency of transformed foci was used as an endpoint. the development of foci with a transformed phenotype was greatly enhanced by tumor promoters (e.g., mezerein, 12-o-tetradecanoyl-phorbol-13-acetate, teleocidin, and o ...	1991	1661204
high rotational mobility of dna in animal cells and its modulation by histone acetylation.	dna rotational mobility in a bovine papilloma virus (bpv)-based minichromosome, autonomously replicating in mouse cells, was studied using topoisomer analysis in temperature shift experiments. it was found that in live cells the average number of topological turns increased by six in the course of temperature shift through a range of 37 degrees c. this comprised approximately 85% of the total potential mobility of naked plasmid dna. dna rotation in isolated nuclei was found to be 3.5-4.0 turns p ...	1991	1661371
[recombinant murine cell lines transformed by various vectors based on bovine papillomavirus type 1 and expressing human tissue plasminogen activator].	we have constructed a number of vectors which include transcriptional unit of human tpa cdna and 100% bpv-1 dna or 100% lx dna (mutant bpv variant with tandem duplication of lcr-e6-e7 region). additional hsv-1 tk-promoter was inserted in the flanks of viral dnaa in a set of constructions. a number of recombinant cell lines have been established by means of transformation using the constructed vectors. the increased focus formation activity and the improved vector properties were demonstrated for ...	1991	1661373
identification of the origin of replication of bovine papillomavirus and characterization of the viral origin recognition factor e1.	expression of the viral polypeptides e1 and e2 is necessary and sufficient for replication of bpv in mouse c127 cells. by providing these factors from heterologous expression vectors we have identified a minimal origin fragment from bpv that contains all the sequences required in cis for replication of bpv in short term replication assays. this same sequence is also required for stable replication in the context of the entire viral genome. the identified region is highly conserved between differ ...	1991	1661672
relationship of histone acetylation to dna topology and transcription.	an autonomously replicating plasmid constructed from bovine papiloma virus (bpv) and pbr322 was stably maintained as a nuclear episome in a mouse cell culture. addition to a cell culture of sodium butyrate (5 mm) induced an increase in plasmid dna supercoiling of 3-5 turns, an increase in acetylation of cellular histones, and a decrease in plasmid transcription by 2- to 4-fold. after withdrawal of butyrate, dna supercoiling began to fluctuate in a wave-like manner with an amplitude of up to 3 tu ...	1991	1662766
enhancer effect of bovine papillomavirus e2 protein in replication of polyomavirus dna.	in polyomavirus, both transcription from the early promoter and viral dna replication initiated at the origin of dna replication is controlled by binding of proteins to the enhancer region. we have developed a simple model system to study the role of an enhancer binding factor in the initiation of polyomavirus dna replication. a reporter plasmid was constructed which has the enhancer region replaced by two binding sites for a transcription factor, the e2 protein encoded by bovine papillomavirus ...	1991	1662803
transactivation of heterologous promoters by hiv-1 tat.	to determine whether hiv-1 tat can transactivate a heterologous promoter lacking hiv sequences other than the tar element, tar was placed downstream of the chicken beta-actin promoter. tat increased expression directed by the actin-tar promoter to a degree equal to tat induction of the hiv-1 ltr. optimal transactivation was observed when tar was positioned downstream of the actin promoter such that the expected cap site of transcripts from this promoter would be the same as in transcripts direct ...	1991	1662814
growth complementation of influenza virus temperature-sensitive mutants in mouse cells which express the rna polymerase and nucleoprotein genes.	in order to establish cell lines which complement the growth of temperature-sensitive (ts) mutants of influenza virus, three rna polymerase and nucleoprotein (np) genes each linked to the mouse mammary tumor virus ltr were cloned into the bovine papillomavirus vector dna. after co-transfection of mouse c127 cells with these recombinant plasmids, a cell line, clone 76, in which the expression of the three polymerase and np genes could be stimulated by dexamethasone, was established. the clone 76 ...	1991	1663110
the papillomavirus e2 protein: a factor with many talents.	the products of the papillomavirus e2 open reading frame play a key role in the regulation of the viral cycle. e2 proteins can activate or repress viral promoters by several distinct mechanisms and viral dna replication requires the expression of the full-length e2 protein together with the product of the e1 open reading frame. this is an interesting example of how a single eukaryotic dna-binding protein has evolved to perform several different functions and it provides a valuable model system f ...	1991	1663669
structures of bovine and human papillomaviruses. analysis by cryoelectron microscopy and three-dimensional image reconstruction.	the structures of bovine papillomavirus type 1 (bpv-1) and human papillomavirus type 1 (hpv-1) were determined at 2.5 nm resolution by cryoelectron microscopy and three dimensional image reconstruction techniques. as expected, the reconstructions showed that both viruses consist of a t = 7 icosahedral capsid (approximately 60 nm in diameter) which surrounds a nucleohistone core. the capsid morphologies of the two viruses are nearly indistinguishable. each capsid consists of a shell layer (approx ...	1991	1663794
tumor progression in transgenic mice containing the bovine papillomavirus genome.		1991	1667568
transcription factor e2 regulates bpv-1 dna replication in vitro by direct protein-protein interaction.		1991	1668086
sequence-specific alkylation of dsdna with derivatives of pyrimidine oligonucleotides conjugated to 2-chloroethylamine groups.	reaction of homopyrimidine oligonucleotides bearing a 5'-terminal alkylating aromatic 2-chloroethyl-amino group with a bovine papilloma vector expressing human interferon-gamma was investigated. the oligonucleotide derivatives bound to corresponding homopurine-homopyrimidine sequences in dsdna and alkylated guanosine residues at these sites in the purine strand of the target. the alkylated dna can be cleaved at the modified residues. at ph 5.4, the reaction was highly specific to the target sequ ...	1991	1668255
generation of c127-derived cell lines expressing estrogen or progesterone receptors for studying gene regulation on bovine papilloma virus minichromosomes.	to study regulation of transcription by multiple steroid hormones we have stably introduced expression vectors for human estrogen and rabbit progesterone receptors into the genome of the murine fibroblast cell line c127. these cells express functional endogenous glucocorticoid receptor and support bovine papilloma virus minichromosomes, a useful system for studying the role of chromatin structure on gene expression. three clones containing progesterone receptor integrates and six containing estr ...	1991	1668831
diagnosis of nasopharyngeal carcinoma by means of recombinant epstein-barr virus proteins.	the immune response of patients with nasopharyngeal carcinoma to epstein-barr virus (ebv) antigens is diagnostic of the tumour. existing tests use ebv antigens produced in ebv-infected lymphoblastoid cells, but the virus replicates poorly in these cells. serum samples from 18 patients diagnosed as having nasopharyngeal carcinoma were screened by western blot analysis, enzyme-linked immunosorbent assay (elisa), and immunofluorescence tests for antibodies to the ebv-coded alkaline deoxyribonucleas ...	1991	1672175
enhancer activation by a single type of transcription factor shows cell type dependence.	promoter and enhancer elements contain multiple binding sites for ubiquitous and cell type-specific transcription factors which stimulate transcription synergistically. here we show that cell type-dependent enhancer activity can be achieved by mechanisms other than interactions between cell type-specific transcription factors and dna. the ability of the sv40 enhancer and the e2 transactivator from bovine papillomavirus (bpv-1) to stimulate transcription from a reporter gene with different minima ...	1991	1714381
comparison of neutralization of bpv-1 infection of c127 cells and bovine fetal skin xenografts.	bpv-1 induces focus formation in murine c127 cells and fibropapillomas in bovine fetal skin xenografts. in this study, we compared the specificity of neutralization of bpv-1 in both assay systems, using sera and monoclonal antibodies (mabs) selected to define neutralizing epitopes. sera from rabbits and cattle, inoculated with intact bpv-1 or pbv-2 virions, neutralize bpv-1 infectivity in both c127 cells and xenografts. selected human sera and murine mabs that react with intact bpv-1 particles, ...	1991	1715330
an element in the bovine papillomavirus late 3' untranslated region reduces polyadenylated cytoplasmic rna levels.	expression of the two bovine papillomavirus type 1 (bpv-1) late genes, l1 and l2, coding for the two capsid proteins, is limited to terminally differentiated keratinocytes in bovine fibropapillomas. this pattern of expression is determined both by the activity of the late promoter and by the inhibition of late region expression in less well differentiated cells. inhibition of l1 and l2 mrna production in nonpermissive cells must occur since the late region potentially could be transcribed from e ...	1991	1717710