| nucleotide sequence of the gene for the major structural protein of sv40 virus. | we have determined the sequence of the portion of simian virus 40 (sv40) that codes for the major structural protein of the virus. the gene contains 361 codons. synonym codons for an amino acid are not used randomly. the dinucleotide cg occurs only once and there is 2 to 1 preference for uridylic acid in the third position of codons. | 1977 | 198745 |
| dna synthesis by partially purified replicating simian virus 40 chromosomes. | we have partially purified replicating simian virus 40 (sv40) chromosomes in a form which allows continued dna synthesis in vitro. we first prepare a soluble dna-synthesizing system from sv40-infected monkey cells and then sediment the components through a neutral sucrose gradient of extremely low ionic strength. replicating sv40 chromosomes isolated from such gradients are capable of continuing dna synthesis in vitro in the same manner as two crude subnuclear systems we have previously describe ... | 1977 | 198750 |
| stimulation of rna synthesis in isolated nuclei by partially purified preparations of simian virus 40 t-antigen. | t-antigen was partially purified from nuclei of cells transformed by simian virus 40 (sv 40). when nuclei isolated from either rat liver or quiescent hamster cells were preincubated with t-antigen preparations, there was a marked stimulation of rna synthesis in an in vitro assay, up to 150% above control levels. the stimulation of rna synthesis was inhibited by hamster antiserum against t-antigen but not by normal hamster serum. when the t-antigen preparations were fractionated on glycerol gradi ... | 1977 | 198774 |
| changes in surface properties of normal and transformed cells caused by tunicamycin, an inhibitor of protein glycosylation. | normal and virally transformed mouse (3t3) and human (wi-38) cells were treated with tunicamycin, an inhibitor of lipid-carrier-dependent glycosylation of proteins. incubation of cells with tunicamycin (1 microgram/ml) caused detachment and death of simian virus 40- and polyoma-transformed cells within 24 hr; these effects were not seen with nontransformed cell lines. however, the proliferation of 3t3 cells was inhibited by tunicamycin and, after a few days, a distinct change from an epithelioid ... | 1977 | 198786 |
| genetic analysis of host range mutant viruses suggests an uncoating defect in simian virus 40-resistant monkey cells. | host range mutations that permit simian virus 40 (sv40) to grow with increased efficiency on sv40-resistant monkey cells have been positioned within the viral b/c gene by a mapping method that relies on the coupling of specific dna fragments. pairs of restriction endonucleases that each cleave sv40 dna at only one site were used to generate pairs of specific dna fragments. corresponding pairs of fragments were purified from host range mutant and wild-type dna and joined in known combinations to ... | 1977 | 198788 |
| novel mechanism for rna maturation: the leader sequences of simian virus 40 mrna are not transcribed adjacent to the coding sequences. | the 5'-terminal 100-200 ribonucleotides of late simian virus 40 (sv40) mrnas are not transcribed immediately adjacent to their coding sequences. this conclusion is based on the following observations. the major late sv40 cytoplasmic rna species, 16s and 19s, were purified from poly(a)-containing cytoplasmic rna by hybridization to and elution from an sv40 dna fragment that maps between 0.67 and 0.76. this fragment is remote from the dna fragments that include the coding sequences. the rna transc ... | 1977 | 198797 |
| purification of simian virus 40 tumor antigen from a line of simian virus 40-transformed human cells. | simian virus 40 tumor antigen can be isolated in a highly purified state from the nuclei ofsv80 cells, a continuous line of simian virus 40-transformed human fibroblasts. a five-step purification method was used. its apparent molecular weight (in sodium dodecyl sulfate/polyacrylamide gels) is approximately 90,000-94,000. it contains a detectable amino-terminal residue. | 1977 | 198802 |
| division of balb/c mouse 3t3 and simian virus 40-transformed 3t3 cells in cellular aggregates. | balb/c mouse 3t3 cells and 3t3 cells transformed by simian virus 40 (sv40) were cultured as aggregates in agitated liquid medium. when maintained with daily medium changes, 3t3 cells incorporated [(3)h]thymidine into acid-insoluble material at a rate (1/4) that of 3t3 cells in logarithmic-phase flat cultures but 16 times that of the same cells in stationary-phase flat cultures. similarly, sv40-transformed 3t3 cells in aggregates incorporated [(3)h]thymidine at (1/3) the rate of sv40-3t3 cells in ... | 1977 | 198811 |
| symmetric transcription of simian virus 40 dna in the nuclei of transformed mouse cells. | | 1977 | 199162 |
| the isolation of tubulin and actin from mouse 3t3 cells transformed by simian virus 40 (sv3t3 cells), an established cell line growing in culture. | tubulin can be purified from mouse sv3t3 cells (3t3 cells transformed by sv40 virus) by several cycles of temperature-dependent polymerization and depolymerization. electron microscopical analysis of the final product reveals morphologically normal microtubules. homogeneous actin can be isolated as a byproduct of the purification procedure. mouse sv3t3 actin and skeletal muscle actin were compared by fingerprint analysis of the tryptic peptides obtained from performic-acid-oxidized protein. the ... | 1977 | 199427 |
| interaction of simian virus 40 chromatin with simian virus 40 t-antigen. | we have studied the binding of the tumor antigen (t-antigen) of simian virus 40 to simian virus 40 chromatin (minichromosomes). the minichromosomes isolated from infected cells by a modification of standard techniques were relatively free of contaminating rna and cellular dna and had a ratio (by weight) of protein to dna of approximately 1; their dna was 50 to 60% digestible to an acid-soluble form by staphylococcal nuclease. cleavage of this chromatin with restriction endonucleases indicated th ... | 1977 | 199733 |
| recombination between endogenous and exogenous simian virus 40 genes. i. rescue of a simian virus 40 temperature-sensitive mutant by passage in permissive transformed monkey lines. | passage of the simian virus 40 (sv40) temperature-sensitive (ts) mutant tsd202 at the permissive temperature in each of three permissive lines of sv40-transformed monkey cv1 cells resulted in the emergence of temperature-insensitive virus, which plated like wild-type sv40 at the restrictive temperature on normal cv1 cells. in independent experiments, the amount of temperature-insensitive virus that appeared after passage on transformed cells was from 10(3)- to 10(6)-fold greater than the amount ... | 1977 | 199739 |
| recombination between endogenous and exogenous simian virus 40 genes. ii. biochemical evidence for genetic exchange. | the genome of the simian virus 40 (sv40) temperature-sensitive (ts) mutant tsd202 rescued by passage on transformed permissive monkey lines (see accompanying paper [y. gluzman et al., j. virol. 24:534-540, 1977]) was analyzed by restriction endonuclease cleavage mapping to obtain biochemical evidence that the rescue of the ts phenotype results from recombination with the resident sv40 genome of the transformed cell. it was demonstrated that the endonuclease r. haeiii cleavage site, which is loca ... | 1977 | 199740 |
| measurements of the genome sizes of simian virus 40 and polyoma virus. | we have measured the genome sizes of simian virus 40 and polyoma virus and found them to be 5,010 +/- 125 base pairs and 5,080 +/- 125 base pairs, respectively. | 1977 | 199745 |
| selective toxicity induced by picolinic acid in simian virus 40-transformed cells in tissue culture. | when cultured normal and sv40-transformed normal rat kidney and balb/3t3 cells were exposed to picolinic acid, cell proliferation ceases. most of the normal cells remained in a quiescent g1 (g0) state and viable for prolonged periods of time. in contrast, sv40-transformed cells progressed to the s and g2 phases of the cell cycle and remained viable only up to 90 to 120 hr. then, most of the cells began to die. however, a very small fraction of the cell population (approximately 0.01 percent) dev ... | 1977 | 200344 |
| immunological relatedness of papovaviruses of the simian virus 40-polyoma subgroup. | viral antigens in permissive cells infected with jc virus, k virus, and sa12 virus were reactive in immunofluorescence tests to antisera against sodium dodecyl sulfate-disrupted simian virus 40 capsids and polyoma vp1. the major capsid polypeptides of all papovaviruses of the simian virus 40-polyoma subgroup are immunologically related. | 1977 | 200567 |
| characterization of simian virus 40-transformed african green monkey cells (cv-1). ii. semipermissive character for viral replication. | | 1977 | 200829 |
| compact form of sv40 viral minichromosome is resistant to nuclease: possible implications for chromatin structure. | we report two new findings bearing on the "supranucleo-somal" level of the structure of the simian virus 40 minichromosome. i) isolated sv40 minichromosome which contains all five histones including hi/i/ exists in solution under approximately physiological ionic conditions as a compact roughly spherical particle approximately 300 a in diameter which is capable of fitting within the virus capsid. in spite of such a compact conformation of the minichromosome individual nucleosomes can be readily ... | 1977 | 200892 |
| histone synthesis during infection of monkey kidney cells with simian virus 40. | the synthesis of histones during lytic infection of bsc-1 (african green monkey kidney) cells with sv40 has been investigated. the synthesis of all five classes of histones was stimulated, and all classes appeared to be stimulated to the same extent. the increase in rate of histone synthesis in response to sv40 infection was detectable several hours before sv40 dna synthesis was measureable, and the rate of histone synthesis decreased at a time when sv40 dna synthesis was occuring at a maximal o ... | 1977 | 200893 |
| identification of amber and ochre mutants of the human virus ad2+nd1. | although human adenoviruses grow poorly in monkey cells, this defect can be overcome either by coinfection of cells with simian virus 40 (sv40) or by insertion of the relevant portion of the sv40 genome into the adenovirus genome to form an adenovirus-sv40 hybrid virus. the nondefective adenovirus-2-sv40 hybrid virus, ad2+nd1, contains an insertion of 17% of the sv40 genome, which codes for at least part of a 30,000 dalton protein. a set of ad2+nd1 host-range mutants that have lost the ability t ... | 1977 | 200921 |
| immunologic selection against simian virus-40 transformed cells: concomitnat loss of viral antigens and early viral gene sequences. | a clonal line of highly oncogenic "spontaneously transformed" mouse cells (t al/n clone 3) was transformed in tissue culture by simian virus 40 (sv40) and subsequently recloned. the clone of sv40-transformed cells (subclone 1) expressed sv40-specific t (nuclear) and transplantation antigens but was 100 times less tumorigenic than the parent t al/n clone 3 cells. when large numbers of subclone 1 cells (10(4)-10(5)) were injected into syngeneic al/n mice, tumors were produced. from the tumors, cel ... | 1977 | 200932 |
| regulatory function of simian virus 40 dna replication for late viral gene expression. | inhibition of simian virus 40 (sv40) dna synthesis prevents late but not early viral gene expression in infected cells. to test whether the late sv40 template specificity is elicited by replicative intermediate dna molecules (ri-dna), we isolated subcellular fractions containing ri-dna from sv-40-infected monkey cells and microinjected these preparations into various cell lines under conditions in which viral dna synthesis was blocked. late sv40 gene expression (v-antigen synthesis) was obtained ... | 1977 | 200935 |
| sequence arrangement of the 5' ends of simian virus 40 16s and 19s mrnas. | electron microscopic examination of molecular hybrids between simian virus 40 dna, that had been cleaved with ecori and then digested with exonuclease iii, and either 16s or 19s mrna produced late during the viral infection cycle indicated that each of these mrnas contained a 5'-terminal "leader" sequence that was encoded in the viral genome at about map position 0.71-0.75. hybridization of each of these mrnas to viral dna immobilized on nitrocellulose filters supported the electron microscopic ... | 1977 | 200942 |
| simian virus 40-specific proteins in the membranes of simian virus 40-transformed hamster and mouse cells. | membranes of simian virus 40-transformed hamster lymphocytes and phagocytes, as well as of transformed mouse fibroblasts, contain two classes of antigenic virus-specific protein. the isoelectric points of these proteins, as defined by isoelectric focusing/immune electrophoresis are at ph 4.5 and 4.7. the molecular weights of the pi 4.5 and pi 4.7 components, determined by isoelectric focusing/dodecyl sulfate polyacrylamide electrophoresis, lie near 58,000 and 90,000-110,000, respectively. the pi ... | 1977 | 200945 |
| on the nucleoprotein core of simian virus 40. | | 1977 | 201093 |
| effect of input multiplicity on the establishment of simian virus 40 persistent infections in rhesus monkey kidney cells. | monolayer cultures of llc-mk2 rhesus monkey kidney cells become persistently infected with simian virus 40 after infection at input multiplicities of 100, 10, or 1 plaque-forming unit per cell. after 3 weeks, all cells of the cultures infected at a multiplicity of 1 plaque-forming unit per cell produced the simian virus 40 t antigen. in contrast, 8 to 11 weeks elapsed before all the cells in the cultures infected at a multiplicity of 100 plaque-forming units per cell produced t antigen. defectiv ... | 1977 | 201570 |
| nucleotide sequence of the dna encoding the 5'-terminal sequences of simian virus 40 late mrna. | we have used a combination of techniques of dna and rna sequence analysis to determine the nucleotide sequence of the portion of simian virus 40 dna preceding and encoding the 5' end of mrna for the structural protein vp2 of simian virus 40. comparison of the sequence with those found in polyadenylated rna in the cytoplasm of infected cells rna shows that the transcript of sequences preceding the structural gene is more abundant than the transcript containing the codons for the protein. between ... | 1978 | 201640 |
| nucleotides sequence of the genes for the simian virus 40 proteins vp2 and vp3. | we have determined the nucleotide sequence of the dna of simian virus 40. the proceeding report (dhar, r., reddy, v.b., and weissman, s.m. (1978) j. biol. chem. 253, 612-620) presents the sequence of a portion of the simian virus 40 dna that overlaps the region encoding the 5' end of the minor structural protein vp2. we report here the sequence of the remainder of the genes for minor structural proteins vp2 and vp3. the results indicate that the mrna for the two proteins is read in the same phas ... | 1978 | 201641 |
| rna primers in simian virus 40 dna replication. ii. distribution of 5' terminal oligoribonucleotides in nascent dna. | | 1977 | 201764 |
| uncoating and gene expression of simian virus 40 in cv-1 cell nuclei inoculated by microinjection. | cv-1 cells were inoculated with simian virus 40 virus within the nucleus or cytoplasm by microinjection. virions were uncoated with great efficiency within the cell nucleus. | 1977 | 201782 |
| capping structures of simian virus 40 19s and 16s mrnas. | in vivo [methyl 3h]-labeled sv40 19s and 16s mrna species were purified and their internal methylation as well as their capping structures analyzed. sv40 viral mrna sedimenting in the 19s region contains approximately equal proportions of m7gpppam and m7gppm6am, while the 16s mrna contains mainly m7gpppm6am. n6 methyl adenosine is located internally within the rna chains of both the 19s and 16s species. | 1977 | 201923 |
| evolutionary variants of simian virus 40. | | 1977 | 201967 |
| purification by affinity chromatography and preliminary characterization of ornithine decarboxylase from simian virus 40-transformed 3t3 mouse fibroblasts. | | 1977 | 202198 |
| asymmetric okazaki piece synthesis during replication of simian virus 40 dna in vivo. | | 1977 | 202391 |
| serum activity inhibiting specific simian virus 40-induced transplantation resistance and its correlation with primary sv40 tumors appearance in hamsters. | using the modified technique of transplantation test, itr serum activity was found in most (14 out of 21) individual hamster sera obtained during the latent period of primary sv40 carcinogenesis (60 days after virus infection when newborn). on the other hand, as a rule, no itr activity was observed in the sera of the same hamsters after tumor appearance and during their growth. itr activity rapidly disappeared from sera of hamsters neonatally infected with sv40 after their successful immunizatio ... | 1978 | 202479 |
| transformation of human cells by temperature-sensitive mutants of simian virus-40. | conditions necessary for the establishment and maintenance of transformation of human cells by wild type and temperature-sensitive mutants of sv40 were examined. for both early and late mutants, the frequency of transformation was found to be up to 5-fold higher, and virus yield 100-fold lower, at 39 degrees than at 33 degrees. no such effect was observed with the wild type virus under the same conditions. this observation is apparently at variance with previously published work, but may be expl ... | 1978 | 202569 |
| incidence, latency, and morphologic types of neoplasms induced by simian virus 40 inoculated intravenously into hamsters of three inbred strains and one outbred stock. | the incidence, latency, and morphologic types of neoplasms induced in hamsters of the three inbred strains lsh/sslak, lhc/lak, and mha/sslak, inocuated iv at 3 weeks of age with 10(7.5) median tissue culture infective dose (tcid50) of simian virus 40 (sv40). were determined and compared with those of the outbred stock lvg/lak. although the incidence and latency were approximately the same in hamsters of the three inbred strains, hamsters of the outbred stock exhibited almost complete resistance ... | 1978 | 202720 |
| electron microscope study of the base sequence homology between simian virus 40 and human papovavirus bk. | 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, t ... | 1978 | 202735 |
| endoribonuclease activity associated with animal rna viruses. | a specific endoribonucleolytic activity was detected when detergent-lysed vesicular stomatitis of sendai virus was incubated with the precursor to escherichia coli trna tyr. the cleavage products produced and the characteristics of the reaction were similar to those previously reported for human kb cell rnase nu. like rnase nu, the virus-associated reaction generates 5'-hydroxyl and 3'-phosphate groups at the cleavage sites. at protein concentrations similar to those used to test vesicular stoma ... | 1978 | 202740 |
| transcription of host-substituted simian virus 40 dna in whole cells and extracts. | viral transcriptional complexes were extracted from the nuclei of monkey kidney cells infected with wild-type simian virus 40 (sv40) or a variant strain containing a high proportion of host-substituted dna molecules. the rnas synthesized by these complexes in an in vitro system were analyzed for their content of sv40 and host sequences by a technique of sequential hybridization to plaque-purified and substituted viral dnas. the relative labeling of the two types of sequences was commensurate wit ... | 1978 | 202741 |
| binding and transcription of simian virus 40 dna by dna-dependent rna polymerase from escherichia coli. | supercoiled simian virus 40 was transcribed more efficiently than nonsupercoiled dna. the effect was increased from two- to fivefold by the addition of rifampin with triphosphates. the number and locations of polymerase binding sites with respect to hin ii-iii restriction fragments were determined. the total number of binding sites was nine, as determined by uv difference spectroscopy. the locations of these binding sites were on the a, b, d, e, f, and g fragments, as determined by gel electroph ... | 1978 | 202742 |
| effect of chemical modification of supercoiled simian virus 40 dna on the rate of in vitro transcription. | superhelical simian virus 40 fi dna could be modified with the single-strand-specific reagent n-cyclohexyl-n'-beta-(4-methylmorpholinium)ethylcarbodiimide (cmc). a limited reaction, of less than 2% of the base pairs, resulted in almost total inhibition of in vitro transcription by dna-dependent rna polymerase from escherichia coli. this effect was shown to be due to dna modification and not to inhibition of polymerase activity by the reagent. inhibition of enzyme activity occurred if the contami ... | 1978 | 202743 |
| polyoma virus-human cell interactions: persistence of t-antigen in two cell lines with and without transformation. | the interaction of polyoma virus and human cells was investigated. abortive infection as evidenced by the synthesis of t-antigen was observed in normal fibroblast and abnormal (transformed) cells but not in normal epithelial cells. a high percentage of simian virus 40-transformed wi-18 va2 and spontaneously transformed be skin cells produced t-antigen after high-multiplicity infection, but most of the cells rapidly lost antigen-producing capacity upon cell passage, and the cultures became negati ... | 1978 | 202745 |
| comparison of two viable variants of simian virus 40. | the dnas of two viable strains of simian virus 40, 776 and 777, have been compared by using restriction endonucleases. differences between the two strains were detected at five separate points on the simian virus 40 genome. one of these differences, in the region of dna coding for the major viral coat protein, was confirmed by tryptic peptide analysis of coat proteins from the two strains. some physiological differences between the two strains were examined and can, in general, be explained by d ... | 1978 | 202746 |
| initiation points for dna replication in nontransformed and simian virus 40-transformed balb/c 3t3 cells. | the number of initiation points for dna synthesis per unit length of dna in rapidly growing cells is greater for simian virus 40-transformed than for nontransformed balb/c 3t3 cells. | 1978 | 202755 |
| 5'-terminal sequences and coding region of late simian virus 40 mrnas are derived from noncontiguous segments of the viral genome. | the region of the simian virus 40 genome complementary to the 5' end of the most abundant poly(a)-containing 19s and 16s mrnas was mapped by hybridization of double-labeled rna ([3h]methyl group and [14c]uridine) to specific dna fragments. chemical identification of methylated residues indicated that a common "leader" sequence adjacent to the 5' terminus of both 19s and 16s mrna is transcribed from dna sequences located between 0.67 and 0.76 map units. the estimated size of this "leader" rna, wh ... | 1977 | 202950 |
| characterization of early simian virus 40 transcriptional complexes: late transcription in the absence of detectable dna replication. | isolation of early viral transcriptional complexes and incorporation in vitro of radiolabeled precursors into nascent rna has permitted an analysis of early simian virus 40 (sv40) transcription. under conditions such that viral dna replication was undetectable, both early and late sv40 rna were synthesized. this finding provides evidence that viral dna replication is not an absolute requirement for late transcription and supports earlier observations that late viral rna is synthesized in sv40-in ... | 1977 | 202957 |
| preparation of large quantities of separated strands from simian virus 40 dna restriction fragments by low-temperature low-salt agarose gel electrophoresis. | | 1977 | 203210 |
| differential inhibition of the rejoining of x-ray-induced dna strand breaks in normal and transformed human fibroblasts treated with 1,3-bis(2-chloroethyl)-1-nitrosourea in vitro. | the effects of 1,3-bis(2-chloroethyl)-1-nitrosourea on the rejoining of x-ray-induced dna strand breaks were examined in normal human fibroblasts (wi-38) and a simian virus 40-transformed derivative (va-13) with the use of alkaline sucrose sedimentation. 1,3-bis(2-chloroethyl)-1-nitrosourea was capable of partially inhibiting repair of x-ray-produced dna strand breaks in both cell types when the drug was added to the culture medium immediately after x-irradiation. however, when 1,3-bis(2-chloroe ... | 1978 | 203388 |
| the isolation of defective variants of simian virus 40 whose genomes contain sequences derived from adenovirus 2 dna. | a new set of hybrid viruses has been isolated whose closed circular genomes 5 to 6 kb in size, contain dna sequences derived in part from adenoviruses 2 and in part from sv40. the structure of these genomes is complex, but in the simplest case, analyses by restriction endonuclease digestion and hybridization indicate that the adenovirus 2 dna is present as a continuous block, of maximum size 2.8 kb. different hybrids contain sequences derived from different segments of the adenovirus 2 genome. | 1978 | 203654 |
| investigation of human urogenital tract tumors of papovavirus etiology: brief communication. | cells cultured from human urogenital cancer and other cancers as well as cells from noncancerous tissues were examined by immunofluorescent staining with antibodies to t-antigens and capsid antigens of papovaviruses bk virus (bkv), jc virus, and simian virus 40(sv40), and to capsid antigens of herpes simplex virus types 1 and 2 and human cytomegalovirus (cmv). cells from early passage cultures of 123 primary tissues and from 14 continuous lines derived from transitional or renal cell carcinoma w ... | 1978 | 203710 |
| cellular and cell-free synthesis of simian virus 40 t-antigens in permissive and transformed cells. | mrna extracted from a variety of simian virus 40 (sv40)-infected monkey cell lines directs the cell-free synthesis of viral t-antigen polypeptides with molecular weights estimated as 90,000 and 17,000. however, the size, abundance, and distribution of these t-antigens synthesized in vivo vary greatly over a range of permissive and transformed cell lines. to establish whether differences in the size of t-antigen polypeptides can be correlated with the transformed or lytic state, recently develope ... | 1978 | 203721 |
| organization and expression of early genes of simian virus 40. | the early region of simian virus 40 codes for at least two immunologically related polypeptides: large-t and small-t, with apparent molecular weights of 90,000-100,000 and 15,000-20,000, respectively. because small-t shares methionine-containing tryptic peptides with large-t, the two polypeptides are probably coded, in part, by a common nucleotide sequence. to locate the coding sequences for large-t and small-t in the dna, the production of these proteins was examined after infection of cv-1 cel ... | 1978 | 203926 |
| similarity of nucleotide sequences around the origin of dna replication in mouse polyoma virus and simian virus 40. | the nucleotide sequence around the origin of replication in dna of mouse polyoma virus was determined by 32p labeling of the 3' terminus of the hap ii-5/alu i-1 dna fragment, with the use of dna polymerase. the result coincided with our previous report on the 32p labeling, with the use of polynucleotide kinase, of the 5' terminus of the hap ii-5/hha i-1 dna fragment, which corresponds to the large part of the present fragment, hap ii-5/alu i-1. a symmetrical (a+t)-rich region containing a five-a ... | 1978 | 203928 |
| carcinogens enhance survival of uv-irradiated simian virus 40 in treated monkey kidney cells: induction of a recovery pathway? | treatment of monkey kidney cells with low doses of carcinogen enhances the survival of uv-irradiated simian virus 40 (sv40). this is true for compounds with uv-like effects (metabolites of aflatoxin b1, n-acetoxyacetylaminofluorene) and compounds with x-ray-like effects (methyl methanesulfonate, ethyl methanesulfonate). this phenomenon resembles the uv-reactivation of viruses in eukaryotic cells. the carcinogen-induced enhancement of the survival of uv-irradiated sv40 is correlated with the inhi ... | 1978 | 203936 |
| phenotypic modification of sv40-transformed hamster lymphoid cells in vivo. | explants of simian virus 40 (sv40)-induced lymphoid tumors yield sv40-t-antigen-positive derivatives that differ from gd248 lymphocytes propagated in suspension culture, (or in vivo), in the following respects: polygonal shape, adhesion to culture substrates in vitro, phagocytic capacity, lack of immunoglobulin and a chromosome complement at least twice that of gd248 lymphocytes. when gd-248 lymphocytes are propagated as suspension in vitro, no such adherent variants can be detected. however, se ... | 1978 | 204420 |
| a single cleavage of simian virus 40 (sv40) dna by a site specific endonuclease from thermus aquaticus, taq i. | a site specific endonuclease from thermus aquaticus, taq i, cleaves simian virus 40 (sv40) dna at a single site. the cleavage site was localized on the physical map by double digestions, using the previously characterized fragments produced by digestion with hae ii, hae iii, alui, hhai, hinfi, or bsti. the taq i site is located at the position that is 56.5% of the unit length from the eco ri site. | 1978 | 204628 |
| active phosphate ion transport in plasma membrane vesicles isolated from mouse fibroblasts. | inorganic phosphate accumulated 8-fold in plasma membrane vesicles derived from simian virus 40-transformed 3t3 mouse fibroblasts when a nacl gradient (external greater than internal) was artificially imposed across the membrane. preincubation with na+ or addition of monensin markedly reduced phosphate accumulation. na+-stimulated phosphate transport was not affected by addition of either dicarboxylic acids, antimycin a, or ouabain and persisted after addition of proton ionophores. the coupling ... | 1978 | 204640 |
| simian virus 40 (sv40) production from sv40-transformed human amnion cells of established lines. | sixteen established cell lines of simian virus 40 (sv40)-transformed human amnion cells were examined for sv40 production. many of these lines produced sv40 for extensive periods. virus production had not ceased for 2 lines after 18 months, for 3 lines after 12 months, and for 3 lines at 3 months after recovery from "crisis". three lines became virus-free in the first month, 1 line in the second month, 1 in the third month, and 1 in the fourth month, and 2 lines stopped virus production between ... | 1978 | 204798 |
| infection of mouse preimplantation embryos with simian virus 40 and polyoma virus. | mouse two-cell embryos, morulae, and blastocysts were killed when infected in vitro with simian virus 40 (sv40) at high multiplicities of infection. polyoma virus was not deleterious for preimplantation embryos, even at a very high multiplicity of infection; however, the outgrowths of polyoma-infected blastocysts disintegrated after several days of culture. indirect immunofluorescence tests revealed the presence of sv40 t and v antigens and polyoma virus v antigen in the nuclei of trophoblastic ... | 1978 | 204944 |
| simian virus 40 chromatin showing nucleosomes in linear bead-like arrangements along extended closed circular dna. | viral nucleoprotein complexes were extracted from nuclei of permissive cells (cv-1) infected with simian virus 40 (sv40) and examined by electron microscopy. sv40 nucleoprotein complexes (sv40 chromatin) showed nucleosomes in linear bead-like arrangements along the extended closed circular dna. the contour length of the sv40 chromatin was only 1.0-1.8 times shorter than that of viral dna obtained after deproteinization. the data suggest that the circular dna in sv40 chromatin can be extended to ... | 1977 | 205093 |
| induction of sister chromatid exchanges by transformation with simian virus 40. | the frequency of sister chromatid exchange (sce) has been followed sequentially after the addition of sv40 to human diploid fibroblast cultures. the sce frequency was nearly the same in uninfected controls and in infected cultures before they became tumor antigen positive. when cells exhibited tumor antigen, the sce frequency increased over a wide range, and changes in chromosome number and structure were observed simultaneously. cells with induced chromosome abnormalities without increased sce' ... | 1978 | 205353 |
| nucleotide sequence of part of the simian virus 40 hind-d restriction fragment. the presumed initiation region of the vp2 gene. | the nucleotide sequence at the beginning of the restriction fragment hind-d from simian virus 40 dna has been derived by partial chemical degradation of (5'-32p)-labeled restriction fragments followed by analysis on polyacrylamide gel according to maxam and gilbert [proc. natl acad. sci. u.s.a. 74, 560-564 (1977)]. the sequence reported here is 140 nucleotides long. it contains an atg codon which presumably corresponds to the initiator codon of the vp2 protein. this codon is preceded by an untra ... | 1978 | 205416 |
| nucleotide sequence of the simian virus 40 hind-k restriction fragment. | the restriction fragment hind-k represents 4.2% of the genome of simian virus 40 (sv40) and is located near the middle of the late region. its nucleotide sequence is reported here. it was mainly established by analysis of transcription products, synthesized by means of escherichia coli rna polymerase and nucleoside triphosphates, one of which was (alpha-32p)-labeled. strand assignment was possible by hybridization of asymmetric, labeled transcripts of total sv40 dna to filter-bound hind-k fragme ... | 1978 | 205417 |
| pathogenesis of malignant neoplasms induced in hamsters by the oncogenic dna simian virus 40 (sv40). | | 1978 | 205441 |
| involvement of dna polymerase alpha in simian virus 40 dna replication. | | 1978 | 205546 |
| the structure and expression of two defective adenovirus 2/simian virus 40 hybrids. | | 1978 | 205653 |
| characterization of the 5'-terminal capped structures of late simian virus 40-specific mrna. | 32p-labeled, late simian virus 40-specific rna was isoalted from infected cv1 cells and completely degraded with rnase t2 and bacterial alkaline phosphatase. the rnase-resistant material was fractionated two dimensionally and further characterized with penicillium nuclease and nucleotide pyrophosphatase. two major 5' termini were identified in late simian virus 40 rna, namely, 7-methyl gppp 2',6-dimethyl apup and 7-methyl gppp 2',6-dimethyl ap 2'-methyl, upup. both 5' termini are present in unfr ... | 1978 | 205672 |
| transformation of balb/c-3t3 cells by tsa mutants of simian virus 40: temperature sensitivity of the transformed phenotype and retransofrmation by wild-type virus. | the function of the a gene of simian virus 40 (sv40) in transformation of balb/c-3t3 cells was investigated by infecting at the permissive temperature with wild-type sv40 and with six tsa mutants whose mutation sites map at different positions in the early region of the sv40 genome. cloned transformants were then characterized as to the temperature sensitivity of the transformed phenotype. of 16 tsa transformants, 15 were temperature sensitive for the ability to overgrow a monolayer of normal ce ... | 1978 | 205675 |
| species-specific cellular dna-binding proteins expressed in mouse cells transformed by chemical carcinogens. | mouse cells transformed by dna and rna tumor viruses and by chemical carcinogens have been examined for the presence of specific dna-binding proteins by dna-cellulose chromatography. using mouse dna-cellulose we have obtained single-stranded dna-binding proteins from two clones transformed by chemical carcinogens. simian virus 40 transformants also have a dna-binding protein [the tumor (t) antigen] that binds to mouse and human dna with comparable affinity. mouse sarcoma virus-transformed cells ... | 1978 | 205864 |
| establishment of clonal human placental cells synthesizing human choriogonadotropin. | seven clonal human placental cell lines were established by transformation of human first-trimester placental cells with simian virus 40. these transformed cells synthesized native human choriogonadotropin (chorionic gonadotropin) (hcg) as well as the free alpha and beta subunits of hcg. the amount of native hcg synthesized by these cells was, however, lower than the amount of free beta subunit. (both hcg and the beta subunit are detected by the radioimmunoassay for beta subunit, but only hcg is ... | 1978 | 205873 |
| differences in behavior and prognosis between leukemic and lymphomatous forms of a transplantable hamster lymphocytic neoplasm induced by simian virus 40. | a lymphocytic leukemia of probable monoclonal derivation, induced in a syrian golden hamster by the oncogenic dna simian virus 40, was adapted to grow in the allogeneic host either as leukemia or as lymphoma. the leukemia, which was produced by transplanting subcutaneously neoplastic lymphocytes that had circulated through and/or proliferated in lymph nodes and spleen, was characterized by dissemination with systemic manifestations and poor prognosis. the lymphoma, which was produced by transpla ... | 1978 | 205878 |
| highly reiterated sequences of simiansimiansimiansimiansimian. | a 172-base pair segment of dna that is repeated several million times in the genome of the african green monkey has been characterized. sequence analysis revealed that the many repeats of this complex unit are not all identical but represent a set of closely related segments: sequence divergence occurs at various positions in the segment in a nonrandom manner. the uncloned segment obtained from monkey dna is compared with a cloned segment of the same dna which was recombined into the genome of s ... | 1978 | 205944 |
| the genome of simian virus 40. | the nucleotide sequence of sv40 dna was determined, and the sequence was correlated with known genes of the virus and with the structure of viral messenger rna's. there is a limited overlap of the coding regions for structural proteins and a complex pattern of leader sequences at the 5' end of late messenger rna. the sequence of the early region is consistent with recent proposals that the large early polypeptide of sv40 is encoded in noncontinguous segments of dna. | 1978 | 205947 |
| properties of simian virus 40 and bk virus tumor antigens form productively infected and transformed cells. | | 1978 | 205997 |
| the effect of interferon on the early functions of simian virus 40. | | 1978 | 206011 |
| the 5'-terminal leader sequence of late 16 s mrna from cells infected with simian virus 40. | the 16 s mrna that directs the synthesis of vp1, the major structural protein of simian virus 40 (sv40), is composed of a leader sequence of 203 nucleotides joined to a transcript that contains all the codons for vp1. the leader is transcribed from dna between 0.723 and 0.762 map units while the vp1 coding transcript is copied from dna from 0.94 to 0.17 map units. the leader sequence joins the transcript of the coding region at a position 42 nucleotides upstream from the initiator codon for vp1 ... | 1978 | 206548 |
| discontinuous dna replication: accumulation of simian virus 40 dna at specific stages in its replication. | | 1978 | 206700 |
| common methionine-tryptic peptides near the amino-terminal end of primate papovavirus tumor antigens. | 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, w ... | 1978 | 206886 |
| spliced early mrnas of simian virus 40. | biochemical methods are presented for determining the structure of spliced rnas present in cells at low concentrations. two cytoplasmic spliced viral rnas were detected in cv-1 cells during the early phase of simian virus 40 (sv40) infection. one is 2200 nucleotides in length and is composed of two parts, 330 and 1900 nucleotides, mapping from approximately 0.67 to approximately 0.60 and from approximately 0.54 to approximately 0.14, respectively, on the standard viral map. the other is 2500 nuc ... | 1978 | 206891 |
| biological activity of purified simian virus 40 t antigen proteins. | proteins related to simian virus 40 (sv40) t antigen uere isolated from cells infected with adenovirus 2/sv40 hybrids ad2+d2 and ad2+nd1 dp2 as well as from a line of human cells (sv80) transformed by sv40. the 96,000- and 107,000-dalton proteins of sv80 and ad2+d2, after injection into the cytoplasm of cultured cells, rapidly accumulate in the nuclei, where they remain antigenically reactive for at least 20 hr and trigger dna synthesis in quiescent cells. by contrast, the 23,000-dalton protein ... | 1978 | 206892 |
| human placental cells transformed by tsa mutants of simian virus 40: a model system for the study of placental functions. | human placental cells were transformed with wild-type simian virus 40 (sv40) and temperature-sensitive sv40 mutants of the a and b classes. four criteria for transformation were used: decreased generation time, increased saturation density, increased efficiency of growth on plastic, and ability to overgrow a nontransformed monolayer. cell lines transformed by tsa mutants lost the transformed phenotype at the restrictive temperature (40 degrees); therefore, the a function of sv40 is required for ... | 1978 | 206898 |
| construction of a viable sv40 variant containing two functional origins of dna replication. | viable variants of simian virus 40 (sv40) have been constructed which contain two functional origins of dna replication (or). the variants were made by introducing, at 0.175 on the sv40 map, a segment of dna containing the viral or. two types of experiments demonstrate that the second or is functional. first, the distribution of radioactivity in pulse-labeled sv40 (i) dna is dramatically altered in the variants when compared with the parental virus. second, electron microscopic examination of vi ... | 1978 | 207442 |
| nucleotide sequence of the restriction fragment hind-f-ecori1 of simian-virus-40 dna (part of the vp1 gene). | the nucleotide sequence of the simian virus 40 (sv40) genome region between the cleavage sites for restriction endonucleases ecori (map position 0) and hindii (map position 0.05) has been determined mainly by the partial chemical dna degradation procedure of maxam and gilbert. this fragment represents 5.3% of the genome of sv40 and is located in the late region, internally in the vp1 gene. the message strand shows only one open reading frame for translation into protein, which connects to the on ... | 1978 | 207520 |
| complete nucleotide sequence of the simian-virus 40 hind-g fragment and localisation of the carboxyl terminus of the vp1 protein. | the restriction fragment hind-g represents 7.0% of the simian virus 40 (sv40) genome. the information present in fragment hind-g is expressed as part of the major, late 16-s messenger rna. the complete nucleotide sequence of the fragment hind-g has now been determined by application of the procedure of maxam and gilbert [proc. natl acad. sci. u.s.a. (1977) 74, 560-564]. it contains 369 nucleotide base pairs. on the basis of the termination code words in the strand with the same polarity as the l ... | 1978 | 207521 |
| nucleotide sequence of the simian-virus-40 dna region coding for the carboxyl-terminal part of the t antigen. | | 1978 | 207522 |
| quantitative correlation between simian virus 40 t-antigen synthesis and late viral gene expression in permissive and nonpermissive cells. | the time-course of intranuclear simian virus 40 (sv40) tumor (t) antigen synthesis and accumulation in permissive cv1 monkey cells and nonpermissive 3t3 mouse cells has been studied by immunofluorescence and cytofluorometry. cv1 cells accumulate t antigen continuously over a period of 48 h after infection, whereas in 3t3 cells the t-antigen content remains about constant and at a comparatively low level. only those cv1 cells which have attained a threshold concentration of intranuclear t antigen ... | 1978 | 207711 |
| rescue of infectious virus from permissive monkey cells containing simian virus 40 dna fragments. | permissive tc7 cells were separately transfected with simian virus 40 (sv40) ecori/hap ii a (74% genome) dna fragments and ecori/hap ii b (26% genome) dna fragments in the presence of deae-dextran. fusion of the progeny of recipient cells receiving the a fragment, tc7 (sv40/74) cells, with tc7 (sv40/26) cells, which had received the b fragment, resulted in sv40 rescue. tc7 (sv40/74 + 26) cells, which had simultaneously received both complementary subgenomes, either spontaneously produced sv40 up ... | 1978 | 207888 |
| recently replicated simian virus 40 dna is a preferential template for transcription and replication. | the template activities for the processes of replication and transcription were compared for recently replicated ("new") and uniformly labeled ("old") simian virus 40 (sv40) dna in infected monkey cells (line tc7). new sv40 dna (pulse-labeled for 1 h) served as a template for a second round of replication with a relatively high probability (8% of the dna replicated per h) for a period of 5 h, after which time its template activity rapidly decreased by severalfold. old sv40 dna (labeled for 24 h) ... | 1978 | 207891 |
| biosynthesis, immunological specificity, and intracellular distribution of the simian virus 40-specific protein induced by the nondefective hybrid ad2+nd1. | ad2(+)nd(1), a nondefective hybrid virus containing a segment of the early region of simian virus 40 (sv40) dna covalently inserted into the human adenovirus 2 genome, enhances the growth of human adenoviruses in simian cells and induces the sv40 u antigen. this hybrid previously has been shown to code for a 28,000 (28k) molecular weight protein not present in wild-type adenovirus 2-infected cells. by radioimmunoprecipitation using sera from hamsters bearing sv40-specific tumors, we have establi ... | 1978 | 207895 |
| simian virus 40 t antigen binds to host cell chromosomes. | | 1978 | 208006 |
| dna polymerase alpha is associated with replicating sv40 nucleoprotein complexes. | simian virus 40 (sv40) nucleoprotein complexes were extracted from nuclei of infected monkey cells and fractionated on neutral sucrose density gradients. complexes which contained replicating sv40 dna (95s) separated well from those containing closed circular supercoiled viral dna (75s). dna polymerase activity was associated with the replicating nucleoprotein complexes but not with the slower sedimenting complexes. this dna polymerase activity coprecipitated with the nucleoprotein complexes in ... | 1978 | 208060 |
| higher order structure of simian virus 40 chromatin. | simian virus 40 nucleoprotein complexes undergo an ionic strength-dependent structural transition. at moderate ionic strength they contain histone h1 as well as the nucleosomal histones and have a compact conformation with globular subunits 190 angstroms in diameter. at high ionic strength histone h1 is released, and the structure unfolds into chains with an average of 24 nucleosomes. the extended viral chromatin converts to the compact form by the addition of histone h1. transcriptionally activ ... | 1978 | 208155 |
| appearance of defective simian virus 40 following infection of cultured human glioblastoma cells. | | 1978 | 208261 |
| genome maps of simian virus 40 defectives propagated in human glioblastoma cells. | | 1978 | 208262 |
| antiserum to polyacrylamide gel-purified simian virus 40 t antigen. | | 1978 | 208264 |
| detection of mason-pfizer monkey virus infection by syncytia formation of human cells doubly transformed by rous sarcoma virus and simian virus 40. | human cells doubly transformed by rous sarcoma virus and sv40 (rsb cells) formed syncytia by cocultivation with mason-pfizer monkey virus (mpmv)-producing cells. this cell fusion was blocked by anti-mpmv serum indicating that the phenomenon is mpmv specific. the rsb cells were successfully used for mpmv infectivity assay in the same manner as kc cells. | 1978 | 208492 |
| altered metabolism of heparan sulfate in simian virus 40 transformed cloned mouse cells. | glycoconjugates have been analyzed from a family of closely related mouse cells: a parent clone and three daughter subclones, two of which expressed the simian virus 40 (sv40) t-antigen. the experimental procedure involved the simultaneous comparison by deae-cellulose chromatography of papain-digested macromolecules from the parent, labeled with [3h]glucosamine, and one of the daughter subclones, labeled with [14c]-glucosamine. three cultures compartments (the medium, the cell surface trypsinate ... | 1978 | 209027 |
| role of the simian virus 40 gene a product in regulation of dna synthesis in transformed cells. | cells transformed by tsa mutants of simian virus 40 (sv40) are temperature sensitive for the maintenance of the transformed phenotype. the kinetics of induction of dna synthesis were determined for hamster cell transformants shifted to the permissive temperature after a 48-h serum arrest at the nonpermissive temperature. dnasynthesis was initiated in the tsa transformants by 8 h after shiftdown was maximal by 12 h. the presence or absence of fetal bovine serum at the time of temperature shift ha ... | 1978 | 209212 |
| simian virus 40 dna extracted from infected cells with sodium deoxycholate no longer reflects its in vivo superhelix density. | when simian virus 40 dna is extracted from infected cells with low concentrations of sodium deoxycholate, which selectively extract non-encapsidated simian virus 40 dna, the dna has a lower average number of superhelical turns than the dna extracted from purified viral particles. during extraction, a partial deproteinization of the dna by a concentration of detergent that did not inactivate a nicking-closing activity led to the removal of some superhelical turns. the dna extracted in this way no ... | 1978 | 209214 |