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Molecular and Cellular Biology Oct 1984Papovavirus-based shuttle vectors containing the bacterial lacI gene were used to show that a mutation frequency in the range of 1% occurs in lacI when such vectors are...
Papovavirus-based shuttle vectors containing the bacterial lacI gene were used to show that a mutation frequency in the range of 1% occurs in lacI when such vectors are transfected into COS7 and CV-1 simian cells, NIH 3T3, 3T6, L, and C127 mouse cells, and human 293 and HeLa cells. This frequency is approximately four orders of magnitude higher than the spontaneous mutation frequency in either mammalian or bacterial cells. The mutations are predominantly base substitutions and deletions and also include insertions from the mammalian genome. Time course experiments argue that mutagenesis occurs soon after arrival of the DNA into the nucleus. However, replication of the vector is not required since mutations occur even when the vector lacks all viral sequences. The high mutation frequency appears to be the characteristic outcome of transfection of DNA into mammalian cells.
Topics: Animals; Cell Division; Chromatography, Ion Exchange; DNA Restriction Enzymes; DNA Transposable Elements; DNA, Viral; Deoxyribonuclease EcoRI; Deoxyribonucleases, Type II Site-Specific; Haplorhini; Humans; Kinetics; Mice; Mutation; Plasmids; Simian virus 40; Transfection
PubMed: 6095032
DOI: 10.1128/mcb.4.10.1951-1960.1984 -
Journal of Virology Jul 1994BK virus is a human papovavirus that latently infects a majority of the world's population. There are more than 30 strains of the virus, most of which differ in the...
BK virus is a human papovavirus that latently infects a majority of the world's population. There are more than 30 strains of the virus, most of which differ in the structure of the early enhancer region. The enhancer of the progenitor strain, WW, from which the other strains can be derived, consists of four conserved DNA domains, P, Q, R, and S. Rearrangement of the enhancer occurs upon passage in tissue culture and is thought to occur during virus replication. The strain under study, PQ, was selected upon passage of the Gardner strain (PPPQS) in the permissive cell line, Vero. Mutational analysis of the entire enhancer region demonstrates the importance of five cis-acting sequences: DNA sites B, C, and F, which have homology to the NF-1 protein binding sequence; one purine-rich motif designated A; and site D, which is similar to an SP-1 protein binding site. Two sites, B and C, appear to have a negative influence on gene activity. To study the functional interactions in more detail, promoter-enhancer constructions that contain different combinations of the five DNA sites linked to the chloramphenicol acetyltransferase gene were tested for early gene activity. The results reveal that the proteins binding to the enhancer functionally cooperate with each other. The effects of making mutations at the DNA sites are very similar to the effects of using excess enhancer DNA sequences to titrate the proteins that bind to the cis-acting DNA sites (in vivo competition). Moreover, the effects of changing the spacing between the DNA sites also demonstrate that there are cooperative interactions among the proteins that bind to the PQ strain enhancer. DNA sites B, C, and F are clearly protected from DNase I digestion by Vero cell nuclear proteins. In addition, mutation of each DNA site alters its sensitivity to DNase I in the presence of Vero cell proteins. Interestingly, mutation of site B affects protein binding to site B as well as to sites A, C, D, and F. These results suggest that cooperative functional and physical interactions occur at the early enhancer of the PQ strain.
Topics: Animals; BK Virus; Base Sequence; Chlorocebus aethiops; DNA, Viral; Deoxyribonuclease I; Enhancer Elements, Genetic; Gene Expression; Genes, Viral; Molecular Sequence Data; Mutagenesis, Site-Directed; Protein Binding; Transcription Factors; Transcription, Genetic; Vero Cells
PubMed: 8207802
DOI: 10.1128/JVI.68.7.4274-4286.1994 -
Proceedings of the National Academy of... Mar 1978The tumor antigens directed by human papovaviruses BK and JC and the monkey papovavirus simian virus 40 have two methionine-containing tryptic peptides in common. These... (Comparative Study)
Comparative Study
The tumor antigens directed by human papovaviruses BK and JC and the monkey papovavirus simian virus 40 have two methionine-containing tryptic peptides in common. These peptides are constituents of the small forms of papovavirus tumor antigen (17,000 daltons) which are present in lytically infected and transformed cells and which are believed to share some amino acid sequences with the amino-terminal portion of the larger tumor antigen species (97,000 daltons). In addition to the two peptides, which are present in all three papovavirus tumor antigens, the larger forms of the tumor antigens specified by simian virus 40 and BK virus share four other methionine-containing tryptic peptides, two of which are also present in the smaller (17,000 daltons) species of antigen. The occurrence of common peptides at the amino-terminal portion of tumor antigens of primate papovaviruses suggests that these conserved regions may play a fundamental role in the function of these proteins and in the propagation of these viruses in nature. The tryptic peptides of the small forms of papovavirus tumor antigen were examined and compared to those present in the large species. Out of a total of nine and ten methionine-containing peptides in the 17,000-dalton tumor antigens of simian virus 40 and BK virus, seven and nine peptides, respectively, are constituents of the corresponding larger (97,000 daltons) forms of the antigen.
Topics: Amino Acid Sequence; Antigens, Neoplasm; Antigens, Viral; BK Virus; Genes, Viral; Molecular Weight; Papillomaviridae; Peptide Fragments; Polyomaviridae; Simian virus 40; Viral Proteins
PubMed: 206886
DOI: 10.1073/pnas.75.3.1131 -
Journal of Virology Feb 1978The superhelical DNA of the HD papovavirus is heterogeneous and consists of two discrete size classes with molecular weights of 3.45 X 10(6) and 3.25 X 10(6). Both size...
The superhelical DNA of the HD papovavirus is heterogeneous and consists of two discrete size classes with molecular weights of 3.45 X 10(6) and 3.25 X 10(6). Both size classes of DNA are encapsidated into HD virion particles. Their relative intracellular amounts differ, depending on the cell system. Vero-76 carrier cultures in which HD virus was detected contain both size classes of DNA, with the larger molecules prevailing by a factor of 10. Five clonal lines derived from Vero-76 cell cultures contain exclusively the larger DNA. On the other hand, after cocultivation of Vero-76 with CV-1 cells for several passages, minicircular DNA is accumulated such that both size classes are synthesized in equal amounts. Any of the originally viral DNA-producing cell lines may, upon subcultivation, cease yielding virus. The RITA cell line of Cercopithecus aethiops origin is the only cell line among numerous ones tested which upon infection permits the establishment of a one-step growth cycle. However, between 6 and 8 days after infection, viral DNA synthesis is discontinued, and a persistent viral infection cannot be established. Physical maps of the genomes were constructed, and it could be shown that the smaller, minicircular DNA had originated from the larger DNA as the result of a deletion. The sequences missing in the minicircular DNA are confined to the relative map position 0.15 to 0.21.
Topics: Cell Line; DNA Replication; DNA Restriction Enzymes; DNA, Superhelical; DNA, Viral; Genes, Viral; Molecular Weight; Nucleic Acid Conformation; Papillomaviridae; Polyomaviridae
PubMed: 625085
DOI: 10.1128/JVI.25.2.596-607.1978 -
Journal of Virology Feb 1975Primary hamster kidney cells were transformed by BK virus, a new human papovavirus. Transformed (HKBK) cell produced BK virus T antigen and induced tumors in hamsters...
Primary hamster kidney cells were transformed by BK virus, a new human papovavirus. Transformed (HKBK) cell produced BK virus T antigen and induced tumors in hamsters that developed antibodies to BK virus T antigen. BK virus was rescued from HKBK cells by Sendai virus-assisted fusion with permissive cells. One out of six cell lines derived from HKBK cell-induced tumors showed the same characteristics as HKBK cells.
Topics: Animals; Antibodies, Viral; Antigens, Neoplasm; Antigens, Viral; Cell Fusion; Cell Line; Cell Transformation, Neoplastic; Cricetinae; Culture Techniques; Fibroblasts; Fluorescent Antibody Technique; Haplorhini; Humans; Kidney; Neoplasm Transplantation; Neoplasms, Experimental; Parainfluenza Virus 1, Human; Polyomavirus
PubMed: 163364
DOI: 10.1128/JVI.15.2.420-422.1975 -
Journal of Virology Jan 1978The base sequence homology between the genomes of simian virus 40 (SV40) and human papovavirus BK (BKV) was studied by the heteroduplex method of Ferguson and Davis (J....
The base sequence homology between the genomes of simian virus 40 (SV40) and human papovavirus BK (BKV) was studied by the heteroduplex method of Ferguson and Davis (J. Mol. Biol. 94:135-149, 1975). When mounted for microscopy in 30% formamide (Tm-35 degrees C), BKV/SV40 heteroduplexes were an average of 92% double-stranded and contained only two small nonhomologous regions that mapped near the junctions between the early and late regions of the SV40 Genome. At higher formamide concentrations, the fraction of duplex DNA in the BKV/SV40 heteroduplexes decreased, indicating significant base mismatching in the homologous regions. The strongest regions of homology were located in the late region.
Topics: BK Virus; Base Sequence; DNA, Viral; Microscopy, Electron; Nucleic Acid Conformation; Polyomavirus; Simian virus 40; Temperature
PubMed: 202735
DOI: 10.1128/JVI.25.1.193-201.1978 -
Proceedings of the National Academy of... May 1993Progressive multifocal leukoencephalopathy results from an opportunistic infection of myelin-producing oligodendrocytes by the glia-specific human papovavirus JC. In...
Progressive multifocal leukoencephalopathy results from an opportunistic infection of myelin-producing oligodendrocytes by the glia-specific human papovavirus JC. In this report, evidence is presented that the glial transcription factor Tst-1, a member of the POU-domain family, stimulates transcription of both early and late viral genes. Stimulation was dependent on site-specific binding of Tst-1 to the JC viral regulatory region and on the presence of an intact amino-terminal transactivation domain within Tst-1. Because of its ability to increase the expression of viral large tumor antigen, Tst-1 stimulated viral DNA replication, without participating directly in the replication event. Our results suggest that Tst-1 is one of the determining factors in the glia specificity of JC virus.
Topics: Base Sequence; DNA-Binding Proteins; Gene Expression Regulation, Viral; Genes, Viral; Humans; In Vitro Techniques; JC Virus; Leukoencephalopathy, Progressive Multifocal; Molecular Sequence Data; Nerve Tissue Proteins; Octamer Transcription Factor-6; Oligodeoxyribonucleotides; Transcription Factors; Transcription, Genetic; Tumor Cells, Cultured; Viral Proteins; Viral Structural Proteins
PubMed: 8389455
DOI: 10.1073/pnas.90.10.4743 -
Journal of Virology May 1994Bovine papillomavirus (BPV) DNA has been reported to restrict its own replication and that of the lytic simian virus 40 (SV40) origin to one initiation event per...
Bovine papillomavirus (BPV) DNA has been reported to restrict its own replication and that of the lytic simian virus 40 (SV40) origin to one initiation event per molecule per S phase, which suggests BPV DNA replication as a model for cellular chromosome replication. Suppression of the SV40 origin required two cis-acting BPV sequences (NCOR-1 and -2) and one trans-acting BPV protein. The results presented in this paper confirm the presence of two NCOR sequences in the BPV genome that can suppress polyomavirus (PyV) as well as SV40 origin-dependent DNA replication as much as 40-fold. However, in contrast to results of previous studies on SV40, most of the suppression of the PyV origin was due to NCOR-1, a 512-bp sequence that functioned independently of distance or orientation with respect to the PyV origin and that was not required for BPV DNA replication. Moreover, NCOR-1 alone or together with NCOR-2 did not restrict the ability of the PyV ori to reinitiate replication within a single S phase and did not require any BPV protein to exert suppression. Furthermore, NCOR-1 did not suppress BPV origin-dependent DNA replication except in the presence of PyV large tumor antigen (T-ag). Since NCOR-1 suppression of PyV origin activity also varied with T-ag concentration, suppression of origins by NCOR sequences appeared to require papovavirus T-ag. Therefore, it is unlikely that NCOR sequences are involved in regulating BPV DNA replication. When these results are taken together with those from other laboratories, BPV appears to be a slowly replicating version of papovaviruses rather than a model for origins of DNA replication in eukaryotic cell chromosomes.
Topics: Antigens, Viral, Tumor; Bovine papillomavirus 1; DNA Mutational Analysis; DNA Replication; DNA-Binding Proteins; Electroporation; Papillomaviridae; Plasmids; Polyomaviridae; Polyomavirus; Regulatory Sequences, Nucleic Acid; S Phase; Sequence Deletion; Suppression, Genetic; Viral Proteins
PubMed: 8151772
DOI: 10.1128/JVI.68.5.3051-3064.1994 -
American Journal of Human Genetics Jul 1979Expression of simian papovavirus 40 (SV40) T-antigen following in vitro infection was studied in skin fibroblasts from patients with Down syndrome (DS) and their parents...
Expression of simian papovavirus 40 (SV40) T-antigen following in vitro infection was studied in skin fibroblasts from patients with Down syndrome (DS) and their parents to determine whether the increased susceptibility to SV40 infection reflected the cytogenetic defect or the leukemia risk associated with this syndrome. As a group, fibroblasts from patients with DS showed elevated T-antigen expression 72 hrs after infection compared to that of a healthy control population. However, among 24 patients tested, the cell lines of only 11 showed statistically significant increases in T-antigen expression. A cell line from a patient with concurrent DS and acute myelogenous leukemia had a normal value. T-antigen expression did not correlate with the percentage of cells trisomic for chromosome 21 in 18 cell lines examined or with the number of copies of this chromosome in disomic and trisomic cell strains cloned from three mosaic patients.Collectively, cell lines from parents of trisomy 21 patients also showed increased susceptibility to SV40 infection; however, in five families tested, a consistent pattern of genetic transmission of elevated T-antigen expression from parent to offspring was not observed. Q-banding of cell lines in one family showed that elevated T-antigen expression is not a marker of parental nondisjunction. Variation in susceptibility to human interferon, an antiviral agent, did not account for variation in T-antigen levels among these cell lines. Thus, the abnormalities of T-antigen expression in DS appear independent of the hyperdiploid state and are not a sensitive indicator of cancer risk.
Topics: Antigens, Viral; Cell Line; Cell Transformation, Viral; Down Syndrome; Female; Fibroblasts; Humans; In Vitro Techniques; Interferons; Male; Mosaicism; Risk; Simian virus 40
PubMed: 225951
DOI: No ID Found -
The Journal of Investigative... Dec 1999This is a case report of an immunocompromised individual who presented with progressive alopecia, friable follicular spinous processes, and erythematous, indurated...
This is a case report of an immunocompromised individual who presented with progressive alopecia, friable follicular spinous processes, and erythematous, indurated papules. Examination of skin biopsies using light microscopy and immunohistochemistry revealed pathologic changes of the follicular inner root sheath epithelium with dystrophic trichohyaline granules. Electron microscopy of thin sections of tissue revealed intracellular viral particles with a size and appearance consistent with those in the Papovaviridae family. Electron microscopy of negatively stained extract from a homogenized lesion also demonstrated icosahedral viruses with papovavirus morphology. We believe this is a previously unreported folliculocentric viral infection in an immunosuppressed human host and have termed this entity "trichodysplasia spinulosa".
Topics: Adult; Facial Dermatoses; Hair Diseases; Hair Follicle; Humans; Immunocompromised Host; Male; Papillomavirus Infections
PubMed: 10674379
DOI: 10.1038/sj.jidsp.5640227