| enhancement of bovine papillomavirus-induced cell transformation by tumour promoters. | cultured c3h/10t1/2 cells transfected with the plasmid pdbpv-1 were used as targets, and the frequency of transformed colonies as the endpoint to test the enhancing capacity of four promoters: 12-o-tetradecanoylphorbol-13-acetate (tpa), 4-o-methyl-tetradecanoylphorbol-13-acetate (4-o-methyl-tpa), mezerein and phorbol-12-retinoate-13-acetate (pra). the frequency of the transfected c3h/10t1/2 cells to form transformed colonies was enhanced in the following order: mezerein greater than pra greater ... | 1988 | 2849505 |
| autonomous functional domains of chemically synthesized human immunodeficiency virus tat trans-activator protein. | hiv-1 encodes a potent trans-activator protein, tat, which is essential for viral gene expression. to study tat domains that function in trans-activation, we chemically synthesized the 86 amino acid tat protein (tat-86) and tat mutant peptides. remarkably, tat-86 is rapidly taken up by cells, and produces a massive and specific stimulation of hiv-ltr-driven rna synthesis. mutant peptides of 21 to 41 amino acids exhibit significant activity. only two regions are essential for trans-activation; we ... | 1988 | 2849509 |
| a dimer of bpv-1 e2 containing a protease resistant core interacts with its dna target. | the e2 proteins encoded by papillomaviruses interact with the viral dna to regulate its transcription. in the present study, we have constructed bacterial vectors expressing the full-length or n-terminal truncated bpv-1 e2 proteins under the control of an inducible promoter. by uv cross-linking experiments we show that a dimer of the intact or truncated e2 protein interacts with a single palindromic site accgnnnncggt. the dna-binding domain of e2 can be reduced to a small protease resistant core ... | 1988 | 2850174 |
| calmodulin as a regulator of cell growth and gene expression. | | 1987 | 2850611 |
| bovine papillomaviruses. | | 1985 | 2850862 |
| papilloma of the ears of calves following tattooing. | | 1988 | 2851971 |
| tumour-associated antigens in primary mouse fibroblasts induced by transformation with bovine papillomavirus type 1. | bovine papillomavirus type 1 (bpv 1) dna was used to transform primary fibroblasts of c57bl/6j mice. transformation frequency in these cells was much lower than in c127 cells and not associated with the appearance of morphologically distinct foci. however, continuous lines of transformed c57bl/6j cells were developed by serial subculturing of transfected cells. these transformed cell lines showed phenotypic properties associated with transformation including abnormal karyotypes. they contained v ... | 1988 | 2852603 |
| tumorigenicity of primary mouse fibroblasts transformed by bovine papillomavirus type 1. | cell lines transformed by bovine papillomavirus type 1 dna were established from transfected primary fibroblast cultures of c57bl/6 mice. southern blot analysis revealed that most of the viral dna in the cells was in episomal oligomeric form. these cell lines were tested for tumorigenicity in nude mice in comparison to properties associated with malignant transformation including growth in low-serum medium, focus formation in agar, and resistance to natural killer cells. two of the 5 cell lines ... | 1988 | 2852654 |
| expression of an immunoglobulin kappa light-chain gene in lymphoid cells using a bovine papillomavirus-1 (bpv-1) vector. | bovine papillomavirus-1 (bpv-1) replicates extrachromosomally in certain murine cell lines, suggesting that vectors based on the bpv-1 replicon might provide a means of obtaining more uniform gene expression among independent transformants. we have tested such a vector for the expression in hybridoma cells of the immunoglobulin kappa light-chain gene, but found that the level of expression varies greatly among transformants. our results also indicate that in these transformants the vector has pr ... | 1988 | 2853103 |
| the genetics of bovine papillomavirus type 1. | | 1988 | 2853608 |
| a novel spontaneous mutation of the bovine papillomavirus-1 genome. | a cell clone (cl.2) having an atypical transformed morphology was isolated from a murine c127 cell culture experimentally infected with a bovine papillomavirus type 1 (bpv-1) virion preparation. cl.2 cells exhibited minimal transformed characteristics and contained multiple copies of a bpv-1 plasmid with a molecular size slightly less than that of the wild type viral genome. a simple deletion of 277 bp was mapped to the distal portion of the viral 69% transforming fragment where the early gene r ... | 1988 | 2853880 |
| sequence-specific and general transcriptional activation by the bovine papillomavirus-1 e2 trans-activator require an n-terminal amphipathic helix-containing e2 domain. | the sequence-specific trans-activator protein of bovine papillomavirus (bpv)-1, e2, strongly increases transcription at promoters containing papillomaviral accg(n)4cggt (e2p) cis motifs, but can also activate a wide range of co-transfected promoters without e2p cores to a lower extent. analysis of multiple e2 mutants in transfected cells revealed that the c-terminal dna binding e2 domain binds to the e2p cis sequences in the form of pre-existing nuclear dimers. the dna binding function of e2 was ... | 1988 | 2854060 |
| r-loop mapping of rna transcripts from bovine papillomavirus type 4. | rna isolated from bovine oesophageal warts was hybridised to bpv-4 genomic dna cloned in a plasmid vector. in r-loop preparations, six major classes of transcripts were mapped. class i, due to an unspliced transcript encompassing the e4/e5 orf region, is most common. in class ii the e4/e5 region is spliced at its 5' end to the e6 orf region, and the rnas appear to have different transcription start points in the e6 orf. some class i r-loops may represent shorter class ii-type transcripts not hyb ... | 1988 | 2855468 |
| a model system for the rescue of cdna encoding transacting transcription activator by contingent replication assay. | | 1988 | 2855627 |
| transcriptional organization of bovine papillomavirus type 4. | seven virus-specific rna transcripts have been identified in tumours induced by bovine papillomavirus type 4 (bpv-4). the rnas measured 4.2, 3.6, 3.0, 2.8, 1.9, 1.6 and 1.0 kilobases (kb). they were mapped on the viral genome by northern blot hybridization to subgenomic probes, by cdna hybridization to viral dna fragments and by s1 analysis of unlabelled and 3' and 5' end-labelled dna fragments. all the rna species are transcribed from the same dna strand, are polyadenylated and with the excepti ... | 1986 | 2878058 |
| promoters and processing sites within the transforming region of bovine papillomavirus type 1. | the mrnas present in bovine papillomavirus type 1 (bpv-1)-transformed c127 cells were studied by primer extension. the results show that two internal promoters are present in the e region of bpv-1 in addition to the previously identified promoter at coordinate 1 (h. ahola, a. stenlund, j. moreno-lópez, and u. pettersson, nucleic acids res. 11:2639-2650, 1983). one, located at coordinate 31, generated a set of mrnas with heterogeneous 5' ends, which may encode the major transforming protein of bp ... | 1987 | 2884331 |
| genetic analysis of bovine papillomavirus type 1 trans-acting replication factors. | the establishment of bovine papillomavirus type 1 in somatic mammalian cells is mediated by extrachromosomal replication and stable maintenance of the viral genome as a multicopy nuclear plasmid. previous studies indicated the requirement of viral gene expression for bovine papillomavirus type 1 replication and plasmid maintenance (m. lusky and m. r. botchan, cell 36:391-401, 1984; turek et al., proc. natl. acad. sci. u.s.a. 79:7914-7918, 1982). to define the viral genes which are necessary for ... | 1985 | 2983102 |
| bovine papillomavirus contains multiple transforming genes. | bovine papillomavirus type 1 (bpv-1) and its cloned full-length dna can transform rodent cells in vitro, and the viral dna persists as an extrachromosomal multicopy plasmid in these transformed cells. previous studies have identified at least five discrete viral rnas that are expressed in bpv-1 transformed cells and have shown that these transcripts share a 3' coterminus. to further define the structure of these rnas and to characterize the functions of individual viral transcripts, we construct ... | 1985 | 2983327 |
| the biology of papillomaviruses and their role in oncogenesis. | a large number of different papillomavirus types have been identified. several viruses often infect the same species and each virus is associated with a defined tissue. recent evidence has shown that certain benign lesions can undergo malignant transformation in both animals and humans in response to genetic or environmental factors. fine mapping of the structure and function of the viral genome may enhance our understanding of the interaction between the virus and the cofactors involved in mali ... | 1985 | 2986520 |
| transformation of cultured equine fibroblasts with a bovine papillomavirus. | fetal equine fibroblasts exposed to bovine papillomavirus became transformed by the criteria of morphological alterations and the acquisition of an increased life span, although they failed to grow in soft agar. papillomavirus genome persisted in the transformed fibroblasts and was apparently not integrated with the cellular genome. these findings support the notion that bovine papillomaviruses are involved in the production of equine sarcoids. | 1985 | 2988095 |
| messenger rnas from the transforming region of bovine papilloma virus type i. | messenger rnas present in c127 mouse cells transformed by bovine papilloma virus type 1 (bpv-1) were studied by the s1 nuclease protection technique, northern blotting, and electron microscopic heteroduplex analysis. the results revealed at least five classes of spliced mrnas which we designate types 1 to 5. they had a common poly(a) addition site located at co-ordinate 53 and all mrnas, except the type 3 mrnas, contained an exon located between co-ordinates 41 and 53. in the type 1 mrnas this e ... | 1985 | 2989533 |
| bovine papillomavirus type 1 monoclonal antibodies. | bovine papillomavirus type 1 (bpv-1) and type 2 (bpv-2) are the etiologic agents of fibropapillomas in cattle. polyclonal antisera produced against bpv-1 structural antigens are cross-reactive with bpv-2. in this study bpv-1 type-specific monoclonal antibodies were produced that were not reactive with bpv-2. these monoclonal antibodies could be used for identification of bpv-1 structural antigens in acetone-fixed, frozen sections by immunofluorescence and formalin-fixed, paraffin-embedded sectio ... | 1985 | 2989600 |
| expression of a functional influenza viral cap-recognizing protein by using a bovine papilloma virus vector. | the gene for the influenza viral pb2 protein, which recognizes and binds the 5'-terminal cap 1 structures (m7gpppnm) on eukaryotic mrnas, was inserted into a bovine papilloma virus vector under the control of a mouse metallothionein i (mt-i) promoter. after transfection of this vector into mouse nih 3t3 cells, a cell line, cpb2, was obtained that produces pb2-specific mrna and authentic pb2 protein. induction of the mt-i promoter with cdcl2 causes about a 10-fold increase in pb2 mrna and protein ... | 1985 | 2989815 |
| human papillomavirus type 16 dna sequence. | the complete nucleotide sequence of hpv16 dna (7904 bp) cloned from an invasive cervical carcinoma was determined. homology comparisons allowed us to align the major open reading frames with the other published papilloma virus dna sequences. the general organization of the open reading frames is similar to that of the other four papillomavirus (bpv1, hpv1a, hpv6b, crpv) already sequenced. the sequence reveals an interruption of the reading frame coding for a suspected e1 protein. | 1985 | 2990099 |
| transactivation of a bovine papilloma virus transcriptional regulatory element by the e2 gene product. | we have mapped a transcriptional regulatory sequence within the 1.0 kb noncoding region of the bovine papilloma virus (bpv-1) genome, using an enhancer dependent expression vector for chloramphenicol acetyltransferase. this transcriptional regulatory element works independently of position and orientation, and its function is significantly augmented in bpv-1 transformed c127 cells and in monkey cv-1 cells acutely transfected with plasmids expressing bpv-1 early gene products. using defined delet ... | 1985 | 2990724 |
| lines of bpv-transformed murine cells that constitutively express influenza virus hemagglutinin. | we have developed and characterized several murine cell lines that constitutively express either the full-length, membrane-bound form of influenza virus hemagglutinin (ha) or a truncated version of the protein (hasec) that lacks the carboxyterminal anchoring sequences and is secreted from cells. cdnas encoding ha or hasec were linked to the murine metallothionein-i promoter or the sv40 early promoter, and inserted into plasmids containing the transforming dna fragment of bovine papilloma virus ( ... | 1985 | 2990897 |
| the presence of bovine papillomavirus type 4 dna is not required for the progression to, or the maintenance of, the malignant state in cancers of the alimentary canal in cattle. | in the western highlands of scotland there is a very high incidence of alimentary cancers in cattle. the carcinomas of the upper alimentary canal are found in association with virus-induced benign papillomas, and transformation of papillomas to carcinomas has been observed. strong circumstantial evidence suggests that the progression to malignancy is due to the interplay between the virus, bovine papillomavirus type 4 (bpv-4), and carcinogen(s) present in bracken fern, which infests the marginal ... | 1985 | 2992946 |
| molecular cloning and nucleotide sequence of deer papillomavirus. | the genome of deer papillomavirus (dpv) isolated from american white-tailed deer was cloned into pbr322, and the entire nucleotide sequence of 8,374 base pairs was determined. the overall genetic organization of the dpv genome was similar to that of other papillomaviruses. all significant open reading frames were located on one strand, and the locations of putative promoters and polyadenylation signals were similar to those identified in the closely related bovine papillomavirus type 1 (bpv-1) g ... | 1985 | 2993669 |
| high spontaneous mutation frequency of bpv shuttle vector. | a recombinant shuttle vector containing the entire bovine papillomavirus (bpv) genome, sequences from pbr322, and the escherichia coli gpt gene was used to transform mouse c127 cells. plasmid extracted from the transformed mouse cells was used to transform a gpt- derivative of e. coli hb101, and the relative frequency of plasmids carrying a mutation in the gpt gene was determined. approximate mutant frequencies of 3-16 x 10(-3) were observed for plasmid molecules which had been passaged through ... | 1985 | 2994240 |
| enzyme-linked immunosorbent assay for the detection of bovine papillomavirus. | an enzyme-linked immunosorbent assay has been developed to detect and quantitate bovine papillomavirus in partially purified and in purified viral preparations, using rabbit antiserum against group-specific papillomavirus structural antigens and alkaline phosphatase-labeled affinity purified goat antibody to rabbit immunoglobulin g. viral detection correlated well with negative-stain electron microscopy of the various preparations and peroxidase-antiperoxidase staining of paraffin sections of th ... | 1985 | 2994527 |
| identification of the protein encoded by the e6 transforming gene of bovine papillomavirus. | papillomaviruses (pv) contain several conserved genes that may encode nonstructural proteins; however, none of these predicted gene products have been identified. papillomavirus e6 genes are retained and expressed as rna in pv-associated human and animal carcinomas and cell lines. this suggests that the e6 gene product may be important in the maintenance of the malignant phenotype. the e6 open reading frame of the bovine papillomavirus (bpv) genome has been identified as one of two bpv genes tha ... | 1985 | 2996134 |
| a cutaneous fibropapilloma from a red deer (cervus elaphus) associated with a papillomavirus. | a cutaneous fibropapilloma was found on a scottish red deer (cervus elaphus), and a papillomavirus was isolated from it. the virus appeared to be related to bovine papillomavirus type 1 (bpv1) or type 2 (bpv2) because: (i) it cross-reacted in peroxidase-antiperoxidase tests with antisera raised against these virions; (ii) bpv1 and bpv2 dnas cross-hybridized to the red deer papillomavirus in situ; and (iii) bpv1 and/or bpv2 dna cross-hybridized to the red deer papillomavirus dna on southern blots ... | 1985 | 2997076 |
| amplification of a bovine papillomavirus-simian virus 40 chimera. | a chimeric plasmid, pbop, containing bovine papillomavirus (bpv) and the origin of replication from simian virus 40 (sv40) was constructed. the plasmid was established in mouse cells, where it was maintained stably as an autonomous bpv replicon. lines carrying pbop were fused to cells of cos-7, a simian line producing sv40 t antigen. replication dependent on the sv40 origin and having the kinetics and approximate amplitude of an sv40 infection ensued. sv40 replication is therefore dominant over ... | 1985 | 2997482 |
| z-dna: still searching for a function. | | 1985 | 2997919 |
| sequence homologies between bovine papillomavirus genomes mapped by a novel low-stringency heteroduplex method. | the bovine papillomaviruses (bpvs) types 1, 2, and 5 cause fibropapillomas whereas bpvs types 3, 4, and 6 cause true papillomas. a novel method of heteroduplex mapping at low stringency of hybridisation has identified the position and relative orientation of distantly related sequences in the genomes of these viruses. the genomes of bpv-1 and bpv-2 are closely related but both show a high degree of sequence divergence from the bpv-5 genome. a 1.25-kb sequence adjacent to the unique bamhi site of ... | 1985 | 2998027 |
| reversion of bovine papillomavirus-induced transformation and immortalization by a xanthate compound. | bovine papilloma virus-transformed hamster embryo fibroblasts (hef-bpv) reacted to exposure to tricyclodecan-9-yl-xanthogenate (d609) with immediate reversion to the growth kinetics and the flat morphology of the untransformed parental cells. after six population doublings in the presence of d609, clones which displayed an untransformed morphology in the absence of d609 arose with a high frequency (90%). such clones had reacquired a limited in vitro lifetime and had lost the ability to induce tu ... | 1985 | 2998840 |
| dissociation of transforming and trans-activation functions for bovine papillomavirus type 1. | it has been shown that genetic information encoded by the 3' open reading frames (orfs), e2, e3, e4 and e5, of bovine papillomavirus type 1 (bpv-1), is sufficient to induce cellular transformation of certain mouse cells. the product of the e2 orf has further been shown to be responsible for the trans-activation of a transcriptional regulatory element located in the noncoding region (ncr) of the bpv-1 genome. to examine whether or not the e2 trans-activation function is encoded by the same gene t ... | 1985 | 2999614 |
| e5 open reading frame of bovine papillomavirus type 1 encodes a transforming gene. | we have previously shown that the early region of the bovine papillomavirus type 1 genome contains two nonoverlapping segments that can independently induce the morphological transformation of cultured cells. the transforming gene from the 5' end of the early region is encoded by the e6 open reading frame. the second transforming segment was previously localized to a 2.3-kilobase fragment (2.3t) from the 3' end of the early region. to determine which of the four open reading frames (e2, e3, e4, ... | 1986 | 3001335 |
| chromosome abnormalities in bovine papillomavirus type 1-transformed syrian hamster cells before and after tumor formation. | syrian hamster embryonic fibroblasts transformed by infection with bovine papillomavirus type 1 cause tumors when inoculated into hamsters. chromosome examinations revealed several abnormal clones in the transformed fibroblasts and a variety of additional markers in three tumors. only one aberration, trisomy 11, was present in each cell. the extra chromosome #11, thus, is considered to be essential for tumor formation in this model system. | 1986 | 3002604 |
| viral dna sequences detected in a hamster liposarcoma induced by bovine papillomavirus type 4. | following intradermal inoculation of bovine papillomavirus type 4 (bpv-4) into a syrian hamster, a liposarcoma developed at the inoculation site 20 months later. the dna of this tumour contained multiple copies of the bpv-4 genome which existed in a free unintegrated state. unintegrated viral dna and viral dna isolated from virus particles from bovine alimentary tract papillomas revealed identical cleavage patterns with cpg methylation-resistant and -sensitive restriction enzymes: apparently the ... | 1986 | 3003234 |
| nonsense mutation in open reading frame e2 of bovine papillomavirus dna. | oligonucleotide-directed mutagenesis was used to construct a nonsense mutation in open reading frame (orf) e2 of bovine papillomavirus dna. a single base substitution mutation was constructed which converted a tac codon into a tag amber stop codon at a position in the orf that did not overlap with any other viral orfs. full-length viral dna containing the mutation induced only approximately 2% of the transformed foci of mouse c127 cells that were induced by wild-type dna. in a different transfor ... | 1986 | 3003380 |
| human papilloma virus and cervical cancer. | | 1986 | 3003916 |
| molecular cloning and characterization of human papillomavirus type 7 dna. | human papillomavirus type 7 (hpv-7) was first described in 1981 but so far could not be molecularly cloned. it has been found almost exclusively in hand warts of butchers. we have cloned the complete genome in pbr 322, established its physical map, demonstrated the colinear genome organization with hpv-18 and analyzed the degree of homology with other hpv types and bovine papillomavirus (bpv) types. in order to investigate whether hpv-7 might be a so far unidentified bovine virus, we screened 37 ... | 1986 | 3004029 |
| translation of open reading frame e5 of bovine papillomavirus is required for its transforming activity. | a series of mutations in open reading frame (orf) e5 of bovine papillomavirus type 1 has been constructed to determine whether this putative gene is required for in vitro oncogenic transformation by viral dna. frameshift mutations at either of two different positions located exclusively in orf e5 cause a substantial reduction in the ability of the cloned viral dna to induce the appearance of transformed foci of mouse c127 cells. a genetic mapping experiment with one of the mutants indicates that ... | 1986 | 3006073 |
| genetic analysis of the 3' early region transformation and replication functions of bovine papillomavirus type 1. | cell transformation by bpv-1 is dependent on sequences confined to a region comprising only 69% of the viral dna. analysis of this subgenomic fragment of the viral genome has revealed a composite of functions. to further study this region of the bpv-1 genome, we constructed mutants affecting the 3' half of the transforming region. these mutations have revealed a plasmid maintenance function for the e2 orf and a requirement that the 3' half of e5 be intact for in vitro mouse cell transformation. ... | 1986 | 3006336 |
| treatment of bovine-papillomavirus-type-1 (bpv)-transformed mouse cells with aromatic retinoid and retinoic acid. | | 1985 | 3006607 |
| monoclonal antibodies to genus- and type-specific papillomavirus structural antigens. | monoclonal antibodies against sds-disrupted bovine papillomavirus type 1 (bpv1) were obtained from hybridomas prepared by fusing mouse myeloma cell line p3x63ag8u1 with spleen cells from immunized balb/c mice. six hybridoma cell lines were obtained after testing supernatant fluids for positivity by the enzyme-linked immunosorbent assay using the immunogen as antigen and by indirect immunofluorescence (if) on frozen sections of bpv1-induced bovine fibropapillomas. monoclonal antibodies (au1-au6) ... | 1986 | 3009351 |
| properties of intracellular bovine papillomavirus chromatin. | episomal nucleoprotein complexes of bovine papillomavirus type 1 (bpv-1) in transformed cells were exposed to dnase i treatment to localize hypersensitive regions. such regions, which are indicative for gene expression, were found within the noncoding part of the genome, coinciding with the origin of replication and the 5' ends of most of the early mrnas. however, there were also regions of hypersensitivity within the structural genes. these intragenic perturbations of the chromatin structure co ... | 1986 | 3009863 |
| expression of the three influenza virus polymerase proteins in a single cell allows growth complementation of viral mutants. | transformed cell lines derived from murine c127 cells were constructed that express the influenza virus rna-dependent rna polymerase proteins (pa, pb1, and pb2). cell lines that express only one or all three of the proteins were tested for their ability to complement temperature-sensitive viral mutants incubated at the nonpermissive temperature. two cell lines were isolated that express all three polymerase genes and complement the growth of pb2 temperature-sensitive mutants at the nonpermissive ... | 1986 | 3010315 |
| human papillomaviruses and cancer. | | 1986 | 3011085 |
| papillomaviruses and their involvement in oncogenesis. | papillomaviruses have been identified as the causative agents of benign epithelial proliferation in many animals including man. recent evidence has shown that each viral type will only infect a specific species and tissue. furthermore, certain papillomavirus types have been found associated with lesions capable of malignant conversion, particularly in response to secondary physical or chemical factors. many advances have been made in identifying particular papillomavirus types inducing papilloma ... | 1985 | 3011141 |
| physical state, expression and regulation of two glucocorticoid-controlled genes on bovine papilloma virus vectors. | we have studied the extrachromosomal maintenance and the transcription regulation of two glucocorticoid-inducible genes on bovine papilloma virus (bpv) vectors in c127 mouse fibroblasts. these genetic elements were the rat tryptophan oxygenase (toase) gene promoter, which is active in vivo only in hepatocytes, and the long terminal repeat of the mouse mammary tumor virus (mmtv-ltr). from both genes, fusions of the 5'-flanking region of the transcription unit to the bacterial gene for chloramphen ... | 1986 | 3012094 |
| structure of bovine papillomavirus type 1 dna in a transformed mouse cell line. | linearized bovine papillomavirus type 1 (bpv-1) dna was introduced into mouse c127 cells, where it recircularized and replicated as an intact monomeric, extrachromosomal circular form in the resulting transformants. these cells contained a mixture of complex high molecular weight forms that were converted to a linear form of approximately bpv-1 size upon digestion with an enzyme that cuts once within the bpv-1 genome. further analysis of one of these cell lines revealed that these high molecular ... | 1986 | 3012096 |
| transient replication of bovine papilloma virus type 1 plasmids: cis and trans requirements. | a transient assay has been used to study bovine papilloma virus type 1 (bpv-1) replication. we show that bpv-1 early replication occurs faster than cellular dna synthesis. initial replication events are dependent on a gene product(s), encoded by the bpv-1 e1 open reading frame. mutational analysis of the viral upstream regulatory region shows the requirement of two domains in cis for replication. domain one, located outside of the viral 69% transforming fragment, is an enhancer-like activity and ... | 1986 | 3012521 |
| criteria for establishing that a virus is oncogenic. | to prove that a particular infectious agent causes a disease is much more difficult in human subjects than in other animals for both ethical and practical reasons. where the disease is a malignant tumour with a long latent period the situation is even more difficult. for these reasons, it is often necessary to concentrate in the first instance on association of the virus with the disease, and this is discussed in the context of papillomaviruses. association of a virus with a tumour may occur for ... | 1986 | 3013518 |
| papillomavirus infection in cattle: viral and chemical cofactors in naturally occurring and experimentally induced tumours. | six different types of bovine papillomavirus (bpv-1 to bpv-6) have been identified and classified into two subgroups: subgroup a, which induce fibropapillomas, and subgroup b, which induce true epithelial papillomas. bpv-4, a member of subgroup b, is the aetiological agent of papillomas of the upper alimentary canal, which can become a focus for transformation to squamous-cell carcinomas in animals feeding on bracken fern. strong circumstantial evidence suggests that the progression to malignanc ... | 1986 | 3013519 |
| immunization against bovine papillomavirus infection. | the two large open reading frames denoted l1 and l2 in the non-transforming region of the bovine papillomavirus type 1 (bpv-1) genome have been molecularly cloned to expression in escherichia coli. antisera against the e. coli-derived l1 and l2 protein reacted with bpv-1 in both enzyme-linked immunosorbent assays and immunoprecipitation reactions. neutralization of bpv-induced transformation of mouse c127 cells was demonstrated most consistently with antisera against the l1 protein. e. coli-deri ... | 1986 | 3013520 |
| organization and expression of the genome of bovine papillomavirus type 1. | the viral mrnas present in c127 cells transformed by bovine papillomavirus type 1 (bpv-1) have been mapped by a variety of techniques, including s1 nuclease analysis, northern blot analysis, primer extension and electron microscopic heteroduplex analysis. the results reveal a very complex mrna pattern, comprising at least five types of spliced cytoplasmic mrnas. both unspliced and partially processed nuclear rna species have also been identified. the transforming region of bpv-1 contains several ... | 1986 | 3013523 |
| papillomavirus transforming functions. | the bovine papillomavirus type 1 (bpv-1) has served as a model for unravelling the molecular genetics of the papillomaviruses. bpv-1 transformation of rodent cells in tissue culture has provided a means to study the viral functions involved in latent infection of cells and in the induction of cellular proliferation functions. bpv-1 has been shown to encode two independent transforming genes, each of which can induce cellular transformation in susceptible rodent cells. these two genes apparently ... | 1986 | 3013525 |
| the bovine papillomavirus replicon. | the bovine papillomavirus genome contains two cis-acting sequences which can serve as signals for replication. at least three virally encoded genes seem to be involved in plasmid replication: e6, e6/7 and e1. mutations in either the e6 or the e7 open reading frame create plasmids that are maintained at a low copy number per cell. mutations in the e1 open reading frame are absolutely lethal to replication. complementation experiments show that these mutations define separate genes. experiments ar ... | 1986 | 3013526 |
| the e5 transforming gene of bovine papillomavirus encodes a small, hydrophobic polypeptide. | bovine papillomavirus (bpv-1) contains two independent transforming genes that have been mapped to the e5 and e6 open reading frames (orf's). the e5 transforming protein was identified by means of an antiserum against a synthetic peptide corresponding to the 20 cooh-terminal amino acids of the e5 orf. the e5 polypeptide is the smallest viral transforming protein yet characterized; it had an apparent size of 7 kilodaltons. the transforming polypeptide is encoded entirely within the second half of ... | 1986 | 3014660 |
| comparison of methods for introducing vectors based on bovine papillomavirus-1 dna into mammalian cells. | the intracellular structure of several vectors based on bpv-1 dna has been analyzed following transfection into mouse c127 cells by the calcium phosphate method or, for the first time, by microinjection directly into the nucleus. it is shown that the method of introduction markedly affects the fate of a bpv-1 based vector. in general, microinjection appears to do little damage to dna and is more likely to result in a vector replicating extrachromosomally as a monomeric structure of the same size ... | 1986 | 3016916 |
| aetiology of enzootic haematuria. | the precise aetiology of enzootic haematuria in cattle remains unknown. the involvement of bracken fern (pteridium aquilinium) appears certain because of the close association between bracken fern infested farms and enzootic haematuria. several toxic principles have been identified but the main carcinogenic element remains to be conclusively demonstrated. more recently, bovine papilloma virus has been implicated in the aetiology of enzootic haematuria. its possible interaction with bracken fern ... | 1986 | 3016971 |
| negative control of dna replication in composite sv40-bovine papilloma virus plasmids. | to identify dna sequences that function in the control of dna replication, we designed a hybrid replicon consisting of linked sv40 and bpv dna sequences. in the composite sv40-bpv plasmid negative control encoded by bpv is dominant over the uncontrolled replication encoded by the positive factor, sv40 t antigen. using a transient replication assay, we show that replication control requires three bpv elements. two cis-acting sequences are closely linked to bpv replication origins. a third trans-a ... | 1986 | 3017566 |
| repression of bovine papilloma virus replication is mediated by a virally encoded trans-acting factor. | cells transformed with bovine papilloma virus type 1 mutants in the e6 or e6/7 genes are resistant to high-copy-number amplification of wild-type dna after supertransfection. transient and stable replication assays demonstrate this effect. if the supertransfected dna has a mutation in a newly defined gene (m), this cellular immunity to high-copy-number replication is overcome, resulting in transient replication of the input dna. in contrast, the resident plasmid does not participate in amplifica ... | 1986 | 3017567 |
| cleavage of vimentin in dense cell cultures. inhibition upon transformation by type 5 adenovirus. | the analysis on two-dimensional isoelectric focusing and sds polyacrylamide gels (2d gels) of the triton x-100 and high salt-insoluble fraction of fibroblast cell lines, certain epithelial cell lines and granulosa cells revealed various amounts of a vimetin cleavage product, with a more basic pi and with a mw (1,500-2,000) lower than that of intact vimentin. this cleavage product of vimentin which constituted as much as 30% of the total vimentin in an established rat embryo fibroblast cell line ... | 1986 | 3017738 |
| the bovine papillomavirus distal "enhancer" is not cis essential for transformation or for plasmid maintenance. | we constructed a mutant of bovine papillomavirus type 1 (bpv-1) dna that lacked a transcriptional enhancer located 3' to the polyadenylation site of the early viral rnas expressed in transformed cells. this mutant dna, when separated from the procaryotic sequences, transforms mouse cells with an efficiency comparable to that of the full bpv-1 genome, and it exists as a stable multicopy plasmid in transformed cells. the bpv-1 distal enhancer suppresses the effects of a cis-inhibitory element in p ... | 1985 | 3018516 |
| type 1 human t-cell leukemia virus small envelope protein expressed in mouse cells by using a bovine papilloma virus-derived shuttle vector. | in an attempt to express the small (transmembrane) envelope protein p21e of type 1 human t-cell leukemia (lymphotrophic) virus (htlv-1) exclusive of other viral gene products, we have constructed a recombinant plasmid clone (pmbe-1) in a bovine papillomavirus-derived mammalian expression vector. mouse c127 cells transfected with the pmbe-1 plasmid expressed the introduced htlv-1 viral gene(s) as demonstrated by northern blot and indirect immunofluorescence with natural human antisera. the transf ... | 1985 | 3018517 |
| enhancer-dependent expression of the rat preproinsulin gene in bovine papillomavirus type 1 vectors. | the effect of position in a bovine papillomavirus type 1 (bpv-1) vector on foreign gene expression was assessed with the rat preproinsulin (ri1) gene. the ri1 gene was inserted at each of the bpv-1/pml2d junctions in either transcriptional orientation in derivatives of the pdbpv-1(142-6) vector which consists of the bamhi linear genome of bpv-1 dna cloned into pml2d. transformed lines of c127 cells were established and assayed for ri1 gene expression. cells containing the ri1 gene at the 3' end ... | 1985 | 3018523 |
| bovine papillomavirus genome elicits skin tumours in transgenic mice. | transmission of the bovine papillomavirus-1 (bpv-1) genome through the mouse germ line results in the heritable formation of fibropapillomas of the skin, a tissue-specific phenotype analogous to that observed in natural bpv-1 infection of cattle. oncogenesis is slow, with tumours first arising at 8-9 months of age, usually in areas prone to wounding. extrachromosomal bpv-1 dna is detected in all tumours, whereas normal tissues show only integrated dna. | 1986 | 3018579 |
| characterization of fischer rat embryo (cref) cells transformed by bovine papillomavirus type 1. | transformation of an established fischer rat embryo (cref) cell line by bovine papillomavirus type 1 (bpv-1), in contrast to transformation by type 5 adenovirus or the t24 (ha-ras) oncogene, resulted in transformants which did not exhibit a major increase in saturation density or a decrease in 125i-epidermal growth factor binding. bpv-1-transformed cref clones did, however, grow in agar suspension culture and were tumorigenic in both nude mice and fischer rats. the majority of transformed clones ... | 1986 | 3019001 |
| differential regulation of papilloma virus early gene expression in transformed fibroblasts and carcinoma cell lines. | treatment of bovine papilloma virus (bpv) 1-transformed mouse fibroblasts with cycloheximide led to a 10-fold increase in the amount of viral transcripts, after as little as 1 h of protein synthesis inhibition. northern blots revealed no qualitative changes in the rna pattern. nuclear run-on experiments showed about a 7-fold increase in specific transcriptional activity after cycloheximide treatment. the half-life of bpv1 mrna was twice as long as in untreated controls. these results indicate th ... | 1986 | 3019673 |
| bovine papillomavirus type 1 3' early region transformation and plasmid maintenance functions. | we examined bovine papillomavirus type 1 (bpv-1) dnas mutated in the e2 open reading frame (orf) to determine their ability (i) to transform c127 cells and (ii) to remain extrachromosomal in transfected cells. results obtained with deletion mutants and insertion mutants containing a linker with translational termination codons in all possible reading frames indicated that an e2 orf gene product(s) is necessary for efficient transformation, as well as viral plasmid replication and maintenance in ... | 1986 | 3021996 |
| a bovine papillomavirus type 1-encoded modulator function is dispensable for transient viral replication but is required for establishment of the stable plasmid state. | a bovine papillomavirus (bpv) type 1-encoded function (m) which is a negative regulator of viral plasmid replication has been described elsewhere (berg et al. cell, in press; roberts and weintraub, cell, in press). we report here that expression of m, which is a repressor of transient bpv replication and is not required as a positive factor in these assays, is required for the establishment of the viral genome as a stable nuclear plasmid. this function is encoded in part by the 5' portion of the ... | 1986 | 3022005 |
| complementation of a bovine papilloma virus low-copy-number mutant: evidence for a temporal requirement of the complementing gene. | we identified a bovine papilloma virus function encoded by the e6/e7 gene, which is required for both bpv high-copy-number replication and maintenance of transformation of cultured cells. a cdna copy of this gene was isolated and expressed from a retrovirus vector. we found that complete complementation of a bpv low-copy-number mutant (dl576) by the cdna encoding the e6/e7 gene was temporally dependent. when both the e6/e7 cdna and dl576 were introduced together into cells, wild-type replication ... | 1986 | 3022134 |
| glucocorticoid inhibition of transcription from episomal proopiomelanocortin gene promoter. | glucocorticoid hormones alter transcription of specific genes. glucocorticoid-stimulated genes have been especially useful in unraveling molecular events responsible for positive gene regulation in mammals. the gene encoding proopiomelanocortin (pomc), which is under feedback inhibition by glucocorticoids, provides a model system to study negative gene regulation. using an episomal bovine papilloma virus vector, we now demonstrate that a 769-base-pair fragment containing the rat pomc promoter is ... | 1986 | 3024155 |
| bovine papillomavirus e2 trans-activating gene product binds to specific sites in papillomavirus dna. | enhancers are cis-acting elements that activate transcription in higher eukaryotes independently of their position or orientation relative to the promoter that they activate. the mechanisms by which enhancers activate transcription are poorly understood, in part because, with the exception of the glucocorticoid receptor, the proteins that directly interact with enhancers have not been purified, nor have the genes encoding them been cloned. the upstream regulatory region (urr) that immediately pr ... | 1987 | 3025749 |
| duplication of a viral enhancer sequence improves the stability of a vector based on bpv-1 dna. | various recombinant constructions involving bovine papillomavirus type 1 (bpv-1) dna and bacterial plasmids have been tested for their ability to transform mouse c127 cells and replicate as intact extrachromosomal monomeric structures. when bpv-1 dna was linked to pbr328, pat153 or derivatives of these plasmids lacking the 344 bp hindiii-bamhi fragment or another small segment, the resulting vectors replicated in c127 cells as high molecular weight structures and, in some cases, deleted extrachr ... | 1986 | 3026114 |
| stability of a bacterial gene in a bovine papillomavirus-based shuttle vector maintained extrachromosomally in mammalian cells. | in order to analyse the stability of cloned genes in a viral vector we have constructed a shuttle vector based on bovine papillomavirus and the escherichia coli gene lacz. propagation of this vector in mouse c127 cells and analysis of vector sequences in bacteria produced no detectable mutations in the lacz gene in over 6137 clones analysed. this is 100-fold less than the mutation frequency observed when the same and similar target genes are replicated in monkey cos cells using a simian virus 40 ... | 1987 | 3027246 |
| mutational analysis of open reading frame e4 of bovine papillomavirus type 1. | open reading frame (orf) e4 is a 353-base-pair orf of bovine papillomavirus type 1. to determine the biological activities of this orf in mouse c127 cells, we analyzed the effects of two constructed mutations which are predicted to prevent synthesis of orf e4 proteins while leaving the amino acid sequence encoded by the overlapping orf e2 unchanged. neither mutation interfered with the abilities of the mutants to efficiently induce focus formation, induce growth in soft agarose, or transactivate ... | 1987 | 3029420 |
| the e2 "gene" of bovine papillomavirus encodes an enhancer-binding protein. | the e2 early open reading frame (presumably gene) of bovine papillomavirus-1 was fused in frame with the collagen-beta-galactosidase-encoding region of the vector pjg200 and was expressed in and partially purified from escherichia coli. the hybrid protein specifically bound to the enhancer region of bovine papillomavirus at several sites. dnase i-cleavage protection analysis of one such site revealed the protected sequence. a comparison of the protected sequence with the remainder of the dna seq ... | 1987 | 3029771 |
| episomal maintenance of a bovine papilloma virus vector in transgenic mice. | we have used a bovine papillomavirus-based vector to generate transgenic mice. transgenic mice result from either pronuclear or cytoplasmic injections of the vector into fertilized eggs. of 30 mice generated by microinjection, 27 (90%) contained the vector in its episomal form, at less than one copy per cell. this represents a highly efficient means of gene transfer in which the transgene is in a controlled genetic environment. | 1987 | 3031486 |
| human papillomavirus type 17 transcripts expressed in skin carcinoma tissue of a patient with epidermodysplasia verruciformis. | certain types of human papillomavirus (hpv) are involved in skin carcinogenesis in epidermodysplasia verruciformis. however, no gene or gene product of hpv associated with skin carcinogenesis has yet been identified. here, we report hpv-17 transcripts expressed in skin carcinoma tissue of an epidermodysplasia verruciformis patient infected with hpv-17. further, we show that one of these transcripts was localized to a portion of the genome which contains the 3' open reading frames of the early re ... | 1987 | 3032809 |
| transcriptional trans-activation by the human papillomavirus type 16 e2 gene product. | we identified a conditional transcriptional enhancer in the long control region (lcr) of human papillomavirus type 16 (hpv-16). this conditional enhancer requires activation in trans by a product of the viral early-region open reading frames (orfs). primer extension analysis of chloramphenicol acetyltransferase rna isolated from transiently transfected cv-1 cells demonstrated that trans-activation of the hpv-16 lcr enhancer operated at the transcriptional level. mutational analysis of the early ... | 1987 | 3033289 |
| dna-binding activity of papillomavirus proteins. | we demonstrate dna binding by papillomavirus (pv) open reading frame (orf) proteins that correspond to the early transforming and trans-activating (e6 and e2) and late structural regions (l2 and l1) from bovine pv type 1 and human pv types 6b and 16. all pv proteins were synthesized in escherichia coli and had a common 13-amino-acid leader sequence from the expression vector pra10. antibodies have been generated in rabbits against these pv proteins. the pv orf proteins bind double-stranded dna, ... | 1987 | 3033292 |
| trans-activation of an upstream early gene promoter of bovine papilloma virus-1 by a product of the viral e2 gene. | the approximately 1000 nucleotide long upstream regulatory region (urr) of bovine papilloma virus-1 (bpv-1) contains a cis element which responds to trans-activation by a diffusible factor encoded in the viral e2 open reading frame (orf). a series of urr dna fragments have been linked to two heterologous genes, bacterial chloramphenicol acetyl transferase (cat) or herpes simplex virus-1 thymidine kinase (tk), and tested in transient transfection assays for transcription initiating at the authent ... | 1987 | 3034572 |
| bovine papillomavirus transcriptional regulation: localization of the e2-responsive elements of the long control region. | the long control region (lcr) of the bovine papillomavirus type 1 genome can function as a conditional transcriptional enhancer which can be specifically trans-activated by the viral e2 gene product. to precisely map the target(s) of this trans-activation, bal 31 exonuclease was used to generate two overlapping series of deleted dna segments through the lcr. these fragments were assayed for their ability to activate transcription from the enhancer-deleted simian virus 40 early promoter of pa10ca ... | 1987 | 3035214 |
| methods for analyzing bovine papilloma virus-based calmodulin expression vectors. | | 1987 | 3035329 |
| [genetic transformation of somatic cells. xi. the autonomic replication of the cloned dna of the bovine papilloma virus in nih/3t3 mouse fibroblasts and the changes in the growth characteristics of the transformed cells]. | mouse fibroblasts nih 3t3 were transfected with the plasmid pbpv (142-6) containing full genome of bovine papilloma virus 1, and focuses of morphological transformation were selected 2-3 weeks later. dna molecules, containing bpv-1 sequences, were isolated from extrachromosomal fraction of transformed clones suggesting stable autonomous replication of bpv in 3t3 nih cells. in some rescued plasmids deletions spanning e6, 7 genes of bpv were found. it is suggested that these genes are not essentia ... | 1987 | 3035762 |
| bovine papilloma virus plasmids replicate randomly in mouse fibroblasts throughout s phase of the cell cycle. | bovine papilloma virus (bpv) replicates as a multicopy nuclear plasmid in mouse fibroblasts. using fluorescence activated cell sorting and mitotic selection procedures, we show that the replication of bpv occurs throughout s phase of the cell cycle and that replication is confined to s phase. after one round of chromosomal dna replication, almost one quarter of bpv plasmids have replicated more than once, while a similar number of plasmids have not replicated at all. while multiple forms of bpv ... | 1987 | 3036365 |
| a transcriptional repressor encoded by bpv-1 shares a common carboxy-terminal domain with the e2 transactivator. | a negative-acting transcriptional regulatory factor encoded by bovine papillomavirus type 1 (bpv-1) was identified. this factor inhibits bpv-1-mediated transformation of mouse c127 cells; inhibition is bpv-1-specific and occurs only when the bpv-1 transforming genes are regulated by authentic transcriptional control elements. plasmids expressing the inhibition function also repress e2 transactivation of the bpv-1 e2-dependent enhancer, and this repression is mediated by the same cis-acting eleme ... | 1987 | 3036366 |
| differential promoter utilization by the bovine papillomavirus in transformed cells and productively infected wart tissues. | expression of the 'late' genes of bovine papillomavirus type 1 (bpv-1) occurs only in the differentiated keratinocytes of the productively infected fibropapilloma. a detailed analysis of viral transcription in the fibropapilloma was performed and compared to bpv-1 specific transcription in transformed c127 cells. a cdna library was constructed from bovine fibropapilloma mrna using the method of okayama and berg. analysis of full length cdnas showed that the majority of viral transcripts in the f ... | 1987 | 3036488 |
| measurement of cell-mediated immunity against bovine papilloma virus by lymphoproliferative reactions. | to study cellular immunity towards bovine papillomavirus (bpv), calves were infected intradermally with bpv-1, and the cellular immune response was measured by the lymphocyte proliferation assay. peripheral blood lymphocytes were obtained which in control experiments were highly reactive towards mitogen stimulation. different batches of bpv-1 were prepared by the use of density gradients. in the first set of experiments, a nonspecific mitogenic effect of the virus preparation was observed. this ... | 1987 | 3036693 |
| purification of papillomavirus structural polypeptides from papillomas by immunoaffinity chromatography. | a broadly cross-reactive monoclonal antibody directed against papillomavirus, coupled to immunoaffinity columns, was used to isolate bovine papillomavirus type 1 (bpv-1) and human papillomavirus type 1 (hpv-1) structural polypeptides from homogenates of productively infected cells. one of the polypeptides isolated from bovine fibropapillomas appeared to be the bpv-1 major capsid protein since it had a mol. wt. of 54k and was reactive by western blots with papillomavirus genus- and bpv-1 type-spe ... | 1987 | 3037012 |
| nucleosomal organization of a bpv minichromosome containing a human h4 histone gene. | to address the relationship between chromatin structure and histone gene expression, the nucleosomal organization of a cell cycle-dependent human h4 histone gene in a bovine papilloma virus (bpv) minichromosome was examined. the nucleosome repeat length of the human h4 histone gene, maintained as a stable episome in a c127 mouse cell line designated i-8, was compared with that of the chromosomal copy of the h4 gene in human (hela) cells. in both cell lines, the h4 histone gene is predominantly e ... | 1987 | 3037307 |
| a promoter with an internal regulatory domain is part of the origin of replication in bpv-1. | extrachromosomal elements that are stably maintained at a constant copy number through cell doublings are a good model system for the study of the regulation of dna replication in higher eukaryotes. previous studies have defined both cis and trans functions required for the regulated plasmid replication of the bovine papilloma virus in stably transformed cells. here, a sequence known to be a cis-dominant element of the replication origin of the plasmid is shown to contain a promoter for transcri ... | 1987 | 3037693 |
| the nucleotide sequence and genome organization of bovine papillomavirus type 4. | the nucleotide sequence of bovine papillomavirus type 4 (bpv-4) was determined. the viral genome is 7261 base pairs long. several overlapping open reading frames (orfs) have been identified both on the basis of amino acid comparison with other papillomaviruses and on their transcriptional pattern. eight early orfs (e1 to 8) were recognized, coding for dna replication and cell transformation functions, and three late orfs (l1 to 3), coding for structural proteins. like the e5 orf of human papillo ... | 1987 | 3039043 |
| identification of proteins encoded by the l1 and l2 open reading frames of human papillomavirus 1a. | the human papillomavirus 1 (hpv-1) virion is composed of two virally encoded proteins: a 57,000-molecular-weight polypeptide (57k polypeptide), which is the product of the l1 open reading frame (orf), and a 78k polypeptide, which is derived from the l2 orf. the 57k (l1) product, which represents the major structural component, appears to be disulfide cross-linked in virus particles. the 78k (l2) protein is a minor component of the virion and does not appear to be disulfide linked either to the l ... | 1987 | 3039170 |
| biology of human papillomavirus (hpv) infections and their role in squamous cell carcinogenesis. | current data implicating the role of human papillomavirus (hpv) infections in squamous cell carcinogenesis may be summarised as follows: animal models have shown that pvs can induce malignant transformation; hpv involvement in both benign and malignant human squamous cell tumours has been demonstrated by morphological, immunohistochemical and dna hybridisation techniques; hpv infections in the genital tract are venereally transmitted and are associated with the same risk factors as cervical carc ... | 1987 | 3039265 |
| contingent replication assay (cra) procedure for rapid isolation of enhancers. | a rapid procedure for the isolation of functional enhancer sequences consists of the construction of a shotgun dna library in sv40-based plasmid shuttle vectors which depend on an enhancer for replication, the replication in monkey (cvi) cells of those vectors into which an enhancer sequence was inserted, the selective cleavage of unreplicated vectors by dpni and the recovery of the replicated vectors by transfection into escherichia coli. we describe conditions for the fusion of protoplasts to ... | 1987 | 3040530 |