| the mechanism of interference between an avian leukosis virus and rous sarcoma virus. ii. early steps of infection by rsv of cells under conditions of interference. | | 1966 | 4287699 |
| studies on rous sarcoma virus in mice. ii. clonal analysis of cell populations of the sr-rsv-induced mouse ascites sarcoma (sr-c3h/he ascites). | | 1967 | 4294688 |
| an electron microscopic study of the chorioallantoic membrane following infection with rous sarcoma virus. | infection of the chick chorioallantoic membrane (cam) with rous sarcoma virus (rsv) has been thought by earlier workers (12, 20) to result in the transformation of the ectoderm and then the mesoderm of that organ. in the present study, cam were infected with 10(4) pfu (pock-forming units) of rsv (bryan high titre strain) and collected for electron microscopy at 2, 4, and 6 days postinfection. observations of the fine structural changes in the cam after rsv infection support a singular role of th ... | 1968 | 4295643 |
| comparative studies with the zilber (carr) strain of rous sarcoma virus (z-rsv). 3. suppression of viral replication and focus formation by interferon in vitro. | | 1967 | 4299770 |
| use of the nucleic acid hybridization method for the demonstration of dna homologous to rous virus rna in rsv-transformed mammalian cells. | | 1969 | 4307533 |
| studies on rous sarcoma virus in mice. 3. three lines of sr-rsv-induced mouse ascites sarcoma. | | 1969 | 4312682 |
| occurrence of phentypically mixed viruses in the bryan high-titer strain of rous sarcoma virus and rsv (rav-1) stocks. | | 1970 | 4312714 |
| hybridization of rna from rous sarcoma virus with cellular and viral dna's. | the rna of rous sarcoma virus (rsv) hybridizes with dna's isolated from all eukaryotes tested (animal and plant) with the possible exception of yeast. bacterial dna's show no homology to rsv-rna. dna's from the oncogenic viruses, adenovirus type 12 and sv40 show significant homology with rsv-rna, but those from nononcogenic adenoviruses types 2 and 4 are not homologous.rsv-rna hybridized to all of the dna's examined has the same, or a closely similar, base composition. moreover, the melting temp ... | 1969 | 4313332 |
| presence of viral genome in chinese hamster embryonic cell transformed in vitro with bryan strain of rous sarcoma virus (b-rsv). | | 1969 | 4314438 |
| virus-specific antigens in hamster cells transformed by rous sarcoma virus. | virus-specific antigens were studied in hamster cells transformed by rous sarcoma virus (rsv). antigens were localized in the cytoplasm, as demonstrated by fluorescent antibody staining of fixed cells as well as by complement fixation (cf) following subcellular fractionation. cytoplasmic extracts were analyzed by velocity and isopycnic centrifugation. cf antigens were found in a soluble form and in association with membranes and polyribosomes. isolated plasma membranes had no cf antigen. both so ... | 1970 | 4315157 |
| investigations on virus production in rsv mammalian tumours. | | 1970 | 4315847 |
| growth curve and distribution of rous sarcoma virus (bryan) in japanese quail. | on primary infection with the bryan strain of rous sarcoma virus (rsv), the growth curve of the virus in the brain of japanese quail was similar to that observed in chicks and turkey poults. infectious virus disappeared from the brain after inoculation. after an eclipse period during which no virus was detectable, infectious virus began to appear at 2 days and reached maximal titers in the brain samples at 7 days after inoculation. when japanese quail were infected intracerebrally with rsv, rela ... | 1967 | 4316245 |
| characteristics of variants of rous sarcoma virus (rsv) isolated from mouse rsv tumors. | | 1970 | 4317738 |
| a cell-associated factor essential for formation of an infectious form of rous sarcoma virus. | formation of a specific type of infectious rous sarcoma virus called rsv(0) has been found to occur only in a certain type of chick embryo cell in the absence of avian leukosis virus. although these chick cells lack any complete form of avian leukovirus, they appear to carry a genetic factor essential for formation of infectious rsv(0). a factor-deficient cell can be converted to a producer of infectious rsv(0) by infection with rous sarcoma virus or avian leukosis virus which has been grown in ... | 1970 | 4317912 |
| mechanism of oncogenic transformation by rous sarcoma virus. i. intracellular inactivation of cell-transforming ability of rous sarcoma virus by 5-bromodeoxyuridine and light. | chick embryo fibroblasts brought into stationary phase of growth by maintenance in serum-free eagle's mem medium were infected with the bryan strain of rous sarcoma virus (b-rsv) and incubated for 18 hr in the presence of 5-bromo-deoxyuridine (budr). the cells were then allowed to resume growth and deoxyribonucleic acid (dna) synthesis by addition of an enriched f12 medium containing serum and rsv antibody to prevent spread of viral infection. after 48 hr, the cultures were exposed for various p ... | 1970 | 4318089 |
| complementarity between rous sarcoma virus (rsv) rna and the in vitro-synthesized dna of the virus-associated dna polymerase. | | 1970 | 4320669 |
| recovery of a new virus from apparently normal chick cells by infection with avian tumor viruses. | cells derived from the majority of chick embryos, although free of presently known avian tumor virus particles, appear to contain genetic materials similar to those found in this virus group. after infection of these cells with avian leukosis or rous sarcoma virus, the genetic factor was recovered by incorporation into mature infectious virus. the newly isolated virus (rav-60) did not require the assistance of another virus for its replication. the virus had most of the attributes of an rna-cont ... | 1970 | 4321346 |
| further characterization of the cellular dna hybridizing with the rna of rous sarcoma virus. | both 70s and 4s rnas of rous sarcoma virus (rsv) contain nucleotide sequences homologous to those in cellular dna. preparations of these rnas were found to include some adventitious cellular srna. nevertheless, both 70s and 4s rsv-rnas were found by competition techniques to contain sequences distinct from those in cellular ribosomal rna and 4s rna. competition experiments also reveal substantial homology between 70s and 4srsv-rna. in hybridization experiments performed in formamide at low tempe ... | 1971 | 4323787 |
| comparison of rous sarcoma virus-specific deoxyribonucleic acid polymerases in virions of rous sarcoma virus and in rous sarcoma virus-infected chicken cells. | labeled virions of rous sarcoma virus (rsv) were disrupted with detergent and analyzed on equilibrium sucrose density gradients. a core fraction at a density of approximately 1.24 g/cc contained all of the (3)h-uridine label and about 30% of the (3)h-leucine label from the virions. endogenous viral deoxyribonucleic acid (dna) polymerase activity was only found in the same location. additional ribonucleic acid (rna)- and dna-dependent dna polymerase activities were found at the top of the gradien ... | 1971 | 4326752 |
| [infectivity for mice of the ribonucleic acid extracted from chicken sarcoma induced by the carr (zilber) strain of rous sarcoma virus (rsv-carr-zilber-rna). i. morphological study]. | | 1970 | 4327545 |
| deoxyribonucleic acid polymerase(s) of rous sarcoma virus: effects of virion-associated endonuclease on the enzymatic product. | purified preparations of rous sarcoma virus (rsv) contain ribonuclease which is either a constituent of the virion surface or an adsorbed contaminant. treatment of the virus with nonionic detergent to activate ribonucleic acid (rna)-dependent deoxyribonucleic acid (dna) polymerase renders the viral genome susceptible to hydrolysis by the external ribonuclease. the extent of this susceptibility can be substantially reduced by the use of limited amounts of detergent. at a concentration of detergen ... | 1971 | 4328411 |
| malignant and transforming activity of rous sarcoma virus (rsv). 3. detection of tumor-specific transplantation and membrane antigens in mouse cell lines transformed in vitro by rsv. | | 1971 | 4328951 |
| dna in uninfected and virus-infected cells complementary to avian tumor virus rna. | the 70s rna component of several avian tumor viruses was hybridized with dna extracted from avian tumor virus-infected and uninfected chicken and japanese quail cells. tritium-labeled 70s rnas from rous sarcoma virus (rsv), rous associated virus-1 (rav-1), rav-60, and schmidt-ruppin-rsv (sr-rsv) hybridize from 3 to 10 times more with dna from uninfected chicken cells than with dna from escherichia coli, calfthymus, or baby hamster kidney cells. after infection of chicken cells with rsv(rav-1), s ... | 1971 | 4332808 |
| [agglutination by concanavalin a of chick embryo fibroblasts transformed by the rous sarcoma virus (sr-rsv) and a thermosensitive mutant of this virus]. | | 1972 | 4334590 |
| [infectivity for mice of ribonucleic acid extracted from chicken sarcoma induced with the carr (zilber) strain of rous sarcoma virus -rsv-(zilber) rna-carr-. ii. histoenzymological study]. | | 1971 | 4335015 |
| hybridization of rous sarcoma virus deoxyribonucleic acid polymerase product and ribonucleic acids from chicken and rat cells infected with rous sarcoma virus. | rous sarcoma virus (rsv)-specific ribonucleic acid (rna) in virus-producing chicken cells and non-virus-producing rat cells infected with rsv was studied by hybridization with the endogenous deoxyribonucleic acid (dna) product of the rsv virion dna polymerase system. by hybridizing the total dna product with excess virion rna, the product dna was separated into hybridized ("minus") and nonhybridized ("plus") dna. the "minus" dna was complementary to at least 20% of the rna from rsv which remaine ... | 1972 | 4337163 |
| [electron microscope study of the fixation of lectins labelled with raifort peroxidase on human embryonic cells transformed in vitro by the rous sarcoma virus (rsv), bryan strain]. | | 1972 | 4339174 |
| role of subunits of 60 to 70s avian tumor virus ribonucleic acid in its template activity for the viral deoxyribonucleic acid polymerase. | heating the 60 to 70s ribonucleic acid (rna) of rous sarcoma virus (rsv) destroys both its subunit structure and its high template activity for rsv deoxyribonucleic acid (dna) polymerase. in comparative analyses, it was found that the template activity of the rna has a thermal transition of 70 c, whereas the 60 to 70s structure dissociates into 30 to 40s and several distinct small subunits with a t(m) of 55 c. analysis by velocity sedimentation and isopycnic centrifugation of the primary dna pro ... | 1972 | 4339194 |
| cell cycle-dependent activation of rous sarcoma virus-infected stationary chicken cells: avian leukosis virus group-specific antigens and ribonucleic acid. | stationary chicken embryo fibroblasts exposed to rous sarcoma virus (rsv) remained stably infected for at least 5 days, but they did not release infectious virus or become transformed until after cell division. these infected stationary cells did not contain avian leukosis virus group-specific antigens or ribonucleic acid (rna) hybridizable to deoxyribonucleic acid (dna) made by the rsv endogenous rna-directed dna polymerase activity. | 1972 | 4339198 |
| temperature-dependent transformation of cells infected with a mutant of bryan rous sarcoma virus. | chick embryo cells infected with a mutant (ta) of the bryan high-titer strain of rous sarcoma virus (rsv-bh) are morphologically transformed at 36 c but appear similar to uninfected cells at 41 c. when cells infected with rsv-bh-ta are switched from 41 to 36 c, morphological changes characteristic of transformation are observable within 10 min. the transformation is reversible; cells shifted from 36 to 41 c have been observed to lose their transformed morphology within 1 hr. the transformation a ... | 1972 | 4342244 |
| dna copies of viral rna in rat cells transformed by rous sarcoma virus (rsv). | | 1972 | 4344277 |
| an enzymatic function associated with transformation of fibroblasts by oncogenic viruses. ii. mammalian fibroblast cultures transformed by dna and rna tumor viruses. | chick, hamster, mouse, and rat embryo fibroblast cultures, transformed by either dna or rna viruses, show fibrinolytic activity under suitable conditions of growth and in appropriate media; normal counterpart cultures do not. the fibrinolysin is produced by the interaction of two protein factors: one of these, a cell factor, is released by transformed cells and accumulates in the medium when cultures are incubated in the absence of scrum. the second factor, the serum factor, is a specific protei ... | 1973 | 4347288 |
| an enzymatic function associated with transformation of fibroblasts by oncogenic viruses. i. chick embryo fibroblast cultures transformed by avian rna tumor viruses. | chick embryo fibroblast cultures develop fibrinolytic activity after transformation by rous sarcoma virus (rsv). this fibrinolytic activity is not present in normal cultures, and it does not appear after infection with either nontransforming strains of avian leukosis viruses or cytocidal rna and dna viruses. in cultures infected with a temperature sensitive mutant of rsv the onset of fibrinolysis appears after exposure to permissive temperatures and precedes by a short interval the appearance of ... | 1973 | 4347290 |
| chromatographic and electrophoretic analysis of viral proteins from hamster and chicken cells transformed by rous sarcoma virus. | several methods have been explored for the detection and characterization of viral proteins from soluble extracts of cells transformed by rous sarcoma virus (rsv). viral antigens have been analyzed after gel filtration in several solvents. in addition, immune complexes formed with virus-specific sera have been isolated by agarose gel filtration and by high- or low-speed centrifugation through sucrose solutions. radioactive proteins from these immune complexes have been analyzed by gel filtration ... | 1973 | 4347428 |
| role of mitochondria in the production of rna-containing tumor viruses. | the role of mitochondria in the reproduction of rna-containing tumor viruses was examined by using ethidium bromide (eb) to induce degenerative effects in mitochondria. the effects of eb in murine and avian cells were monitored by electron microscopy. chronically infected mouse (jls-v5) cells, in which extensive mitochondrial changes were induced, continued to produce murine leukemia virus. also, complete reproductive cycles of rous sarcoma virus (rsv) occurred in newly infected chicken embryo c ... | 1973 | 4347431 |
| relationship of reticuloendotheliosis virus to the avian tumor viruses: nucleic acid and polypeptide composition. | the rna content and polypeptide composition of reticuloendotheliosis virus (rev) was compared to that of c-type rna tumor viruses. two rna species with approximate sedimentation values of 64s and 4s were observed after sucrose gradient centrifugation of rna extracted from purified rev. the high-molecular-weight rna species of rev sedimented slightly faster than that of the bryan strain of rous sarcoma virus (rsv). although these characteristics were consistent with those of other c-type rna tumo ... | 1973 | 4350718 |
| sugar transport in normal and rous sarcoma virus-transformed chick-embryo fibroblasts. | 3-o-methylglucose (3-omeg) is a nonmetabolizable glucose analog and is, therefore, suitable for transport studies. 3-omeg and glucose compete for entry into normal and rous sarcoma virus (rsv)-transformed chick-embryo fibroblasts. therefore, 3-omeg can be used to study the transport of glucose in these cells. chickembryo fibroblasts infected and transformed by rsv take up 3-omeg at a faster rate than uninfected cells when both cell types are growing at the same rate. the rate of efflux of 3-omeg ... | 1973 | 4351798 |
| transformation of chick-embryo fibroblasts by wild-type and temperature-sensitive rous sarcoma virus alters adenylate cyclase activity. | the activity of the enzyme adenylate cyclase, a component of the plasma membrane, has been determined in chick-embryo fibroblasts and in cells transformed by either bryan high-titer strain of rous sarcoma virus (rsv-bh) or a temperature-sensitive mutant of this virus (rsv-bh-ta). adenylate cyclase activity is reduced in cells transformed by the wild-type virus and also by the temperature-sensitive mutant when the cells are grown at the permissive temperature (37 degrees ). transformation results ... | 1973 | 4352222 |
| safety and antigenicity of temperature sensitive (ts) mutant respiratory syncytial virus (rsv) in infants and children. | | 1973 | 4353352 |
| dna polymerase of murine sarcoma-leukemia virus: lack of detectable rnase h and low activity with viral rna and natural dna templates. | kirsten murine sarcoma-leukemia virus (ki-msv[mlv]) was found to contain less rnase h per unit of viral dna polymerase than avian rous sarcoma virus (rsv). upon purification by chromatography on sephadex g-200 and subsequent glycerol gradient sedimentation the avian dna polymerase was obtained in association with a constant amount of rnase h. by contrast, equally purified dna polymerase of ki-msv(mlv) and moloney [mo-msv(mlv)] lacked detectable rnase h if assayed with two homopolymer and phage f ... | 1973 | 4357518 |
| nucleotide sequence relationships of avian rna tumor viruses: measurement of the deletion in a transformation-defective mutant of rous sarcoma virus. | stocks of cloned helper-independent rous sarcoma virus (rsv) spontaneously segregate transformation-defective (td) mutants that appear to have an rna genome composed of smaller subunits than those of the patent virus. differential hybridization and competitive hybridization techniques involving reactions between viral rna and proviral sequences in host cell dna (under conditions of initial dna excess) were used to measure the extent of the deletion in a td mutant of prague strain (pr) of rsv (pr ... | 1974 | 4362512 |
| virus productive transformation of marsupial cells by schmidt-ruppin strain of rsv. | | 1974 | 4363168 |
| requirement for cell division for initiation of transcription of rous sarcoma virus rna. | stationary chicken embryo fibroblasts exposed to rous sarcoma virus (rsv) did not synthesize virus rna until after division of the infected cells. initiation of rna transcription after cell division resulted in transcription of the entire viral genome and was followed shortly thereafter by appearance of progeny virus. addition of colchicine to rsv-infected stationary chicken embryo fibroblasts resulted in inhibition of cell division and a 24-h delay in the appearance of virus rna. rsv-infected c ... | 1974 | 4369144 |
| sarcoma and transformation-defective viruses produced with infectious dna(s) from rous sarcoma virus (rsv)-transformed chicken cells. | | 1974 | 4371384 |
| distribution of fibroblast surface antigen: association with fibrillar structures of normal cells and loss upon viral transformation. | the localization of a cell type-specific, soluble fibroblast surface antigen (sfa) was studied by immunofluorescence and by scanning electron microscopy of the same cells. the antigen had an uneven distribution forming streaks on chick embryo fibroblasts. it was localized to membrane processes and ridges, with a diameter of 50-200 nm. the processes extended from the periphery of the cells to the substratum or to other cells. trypsin treatment completely removed detectable amounts of sfa. the ant ... | 1974 | 4372293 |
| results of investigations concerning the oncogenicity for mice and hamsters of nuclei acid preparations extracted from chicken sarcoma induced by the carr (zilber) and bryan strains of rous sarcoma virus (rsv). | | 1974 | 4377313 |
| comparative studies with the zilber (carr) strain of rous sarcoma virus (z-rsv). i. response of chicken embryo fibroblasts to infection with z-rsv. | | 1967 | 4382475 |
| comparative studies with the zilber (carr) strain of rous sarcoma virus (z-rsv). ii. antigenic relationships and cyst producing capacity in newborn rats. | | 1967 | 4382988 |
| separation and concentration of respiratory syncytial virus (rsv) antigens. | | 1974 | 4827015 |
| pathological changes in virus infections of the lower respiratory tract in children. | the pathological changes are described in 22 children with proven or suspected virus infection of the lower respiratory tract. two main patterns of disease were found: acute bronchiolitis and interstitial pneumonia. particular viruses were not specifically associated with particular histological changes. the prime importance of the respiratory syncytial virus (rsv) as a cause of disease and death in young infants is again shown. structural lesions and clinical dysfunction correlate fairly well; ... | 1970 | 4909103 |
| an avian leukosis virus related to rsv(o): properties and evidence for helper activity. | | 1971 | 5101017 |
| quantitative assay system for the transmission of rsv genome from virogenic mammalian cells into the chicken cell with the help of the sendai virus. | | 1968 | 5653136 |
| genetic variation in the ability of a planthopper vector; laodelphax striatellus (fallén) to acquire the rice stripe virus. | | 1967 | 6025062 |
| the characterization and uses of monoclonal antibodies to respiratory syncytial virus. | fifteen hybridomas secreting monoclonal antibodies against respiratory syncytial virus (rsv) have been produced. three react with nucleoprotein (mw 42 000 daltons), 1 with phosphoprotein (mw 36 000 daltons), 1 with a larger protein (mw 60 000 daltons) and 10 with the fusion glycoprotein (mw 46 000 + 22 000 daltons). by immunofluorescent staining of infected cells, 5 monoclonal antibodies bind to cytoplasmic inclusions and the remainder give diffuse cytoplasmic fluorescence. virus infectivity is ... | 1984 | 6084614 |
| role of cell division in differentiation of myoblasts infected with a temperature-sensitive mutant of rous sarcoma virus. | the relationship between a potential requirement for cell dna synthesis and the expression of differentiated muscle cell functions was investigated using primary chicken embryo myoblasts infected with a temperature-sensitive mutant of rous sarcoma virus (rsv). under optimized conditions, transformed myoblasts growing at the permissive temperature could differentiate into multinucleated myotubes, express muscle-specific myosin, desmin and acetylcholine receptors in the absence of dna synthesis an ... | 1984 | 6086316 |
| multiple enhancer domains in the 3' terminus of the prague strain of rous sarcoma virus. | the 3' terminal region of the prague strain of rous sarcoma virus (prrsv) contains at least three distinct domains that comprise two functional enhancer elements. two of these domains (designated b and c) are found in the u3 region of the 3' long terminal repeat (ltr) while the third (designated a) is located in the sequences immediately preceding the ltr termed xsr sequences. combinations of adjacent domains [e.g., (a + b or b + c)] are capable of activating the expression of the sv40 early pro ... | 1984 | 6089114 |
| characterization of cryptovirogenic, virus-productive and helper-dependent virogenic hamster tumour cell lines. | three hamster cell lines were established from tumours induced with the virus rescued from xc cells. the h-20 cell line produces little infectious transforming virus and synthesizes uncleaved pr76 (product of gag gene) in the amount comparable to that obtained from pr-rsv-c-infected permissive cells. like the helper-dependent virogenic h-18 cell line, it however produces only a marginal amount of viral glycoprotein (env gene product) as revealed by the complementation assay. even a lower amount ... | 1984 | 6090228 |
| different importance of primary lymphoid organs for rous sarcoma regression in inbred lines of chickens. | resistance to progressive growth of tumours induced by rous sarcoma virus is controlled mainly by genes linked to the b complex (the major histocompatibility complex) of the chicken. the effect of thymectomy and bursectomy on this resistance was studied in chickens from highly inbred lines and their f1 hybrids which differ by the genotype at the b complex and by the degree of genetically controlled resistance or susceptibility. the results show that thymectomy has considerable effect on growth o ... | 1984 | 6090231 |
| genetic effects of injection of rous sarcoma virus dna into polar plasm of early drosophila melanogaster embryos. | retroviral proviruses and the transposable elements of eukaryotic genomes are structurally similar. the biological significance of eukaryotic transposable elements has not been examined extensively but it is known that, like prokaryotic transposons, these elements can induce mutations in adjacent genes and cause their transposition. it is of interest to determine whether retroviral proviruses have the same mutagenic and gene transposing ability as transposable elements, particularly because the ... | 1984 | 6090937 |
| detection of virus-specific sequences in drosophila melanogaster mutants induced by injection of rsv dna into early embryos. | the injection of purified rous sarcoma virus (rsv) (prague strain) into drosophila melanogaster (oregon r line) eggs changes the fly phenotype in certain cases, and rsv-specific sequences can be identified in the drosophila genome (ref. 1 and preceding paper). here we have used southern blotting to analyse in greater detail the proviral dna present in several mutant lines of d. melanogaster produced by microinjection of intact rsv or plasmid dna containing the viral insert. in certain population ... | 1984 | 6090938 |
| hormonal regulation of the rous sarcoma virus src gene via a heterologous promoter defines a threshold dose for cellular transformation. | we have derived rat cell lines producing different and regulatable amounts of pp60v-src by introducing the src gene of rous sarcoma virus (rsv) under the control of the glucocorticoid-responsive transcriptional promoter from the mouse mammary tumor virus (mmtv). we find that the cellular phenotype is strictly dependent upon the dose of pp60v-src with a distinct threshold for changes indicative of neoplastic potential. cells with low constitutive levels of pp60v-src are not phenotypically disting ... | 1984 | 6091899 |
| [induction of unstable mutations in drosophila melanogaster by the microinjection of oncogenic viruses and their dna into early embryos]. | rna-containing raus sarcoma virus, recombinant plasmid pbr322 inserted by kdna rsv (pprc11) and sa7 adenovirus dna were injected into the polar region of drosophila melanogaster early embryons. the exogenic genetic material injected was shown to induce mutations, many of them unstable. in a number of cases, virus-specific sequences were found in dna isolated from mutant flies. it is hypothesized that mutations induced by dna of oncogenic viruses are of the insertion type. | 1984 | 6092212 |
| evidence for two distinct c-src loci on human chromosomes 1 and 20. | a number of proto-oncogenes have recently been localized to the chromosomal segments that are the breakpoints in the specific rearrangements noted in human malignant diseases. moreover, rearranged forms of several proto-oncogenes have been identified in malignant cells; in several instances, the proto-oncogene has undergone an alteration as a result of a nonrandom chromosomal rearrangement. one proto-oncogene that has yet to be associated with human neoplastic disease is c-src, the cellular homo ... | 1984 | 6092965 |
| phenotypic changes and loss of n-cam-mediated adhesion in transformed embryonic chicken retinal cells. | transformation of 6-d-old embryonic chicken retinal cells by rous sarcoma virus (rsv) was found to cause significant changes in several cellular properties including adhesiveness, motility, and state of differentiation. the alterations in cell adhesivity were analyzed by means of specific antibodies to the calcium-independent neural cell adhesion molecule, n-cam. in the rsv-transformed cells the amount of n-cam present at the cell surface was significantly decreased relative to normal cells, as ... | 1984 | 6094590 |
| mutations of the rous sarcoma virus env gene that affect the transport and subcellular location of the glycoprotein products. | the envelope glycoproteins of rous sarcoma virus (rsv), gp85 and gp37, are anchored in the membrane by a 27-amino acid, hydrophobic domain that lies adjacent to a 22-amino acid, cytoplasmic domain at the carboxy terminus of gp37. we have altered these cytoplasmic and transmembrane domains by introducing deletion mutations into the molecularly cloned sequences of a proviral env gene. the effects of the mutations on the transport and subcellular localization of the rous sarcoma virus glycoproteins ... | 1984 | 6094591 |
| integration and expression of several molecular forms of rous sarcoma virus dna used for transfection of mouse cells. | to assess the factors required for integration and expression of retroviral dna, we have examined viral dna, rna, and protein in nih/3t3 mouse cells transformed by transfection with various forms of cloned rous sarcoma virus (rsv) dna. linear rsv dna molecules, derived from circular dna containing two long terminal repeats (ltrs) and permuted by cleavage at the saci restriction endonuclease site in the leader sequence, were integrated near the ends of the linear molecule, with the ltrs on the 3' ... | 1984 | 6095056 |
| an assay for transient gene expression in transfected drosophila cells, using [3h]guanine incorporation. | we have developed an assay for transient gene expression using a dominant-selectable marker previously employed to transform drosophila cultured cells. drosophila hydei cells transfected with a functional escherichia coli xanthine guanine phosphoribosyl transferase gene (gpt), under the control of the long terminal repeats (ltrs) of the copia transposable element, rapidly incorporate guanine into acid-precipitable counts. autoradiographic analysis in situ shows that approximately 20% of cells ta ... | 1984 | 6096129 |
| avian erythroblastosis virus e26: nucleotide sequence of the tripartite onc gene and of the ltr, and analysis of the cellular prototype of the viral ets sequence. | an intact 5.7-kb provirus of the avian erythroblastosis virus e26 has been molecularly cloned for comparisons with avian myeloblastosis virus (amv) and other avian tumor viruses. e26 and amv transform hemopoietic cells exclusively. both cause myeloblastosis, but e26 also causes erythroblastosis. sequence analysis of the proviral dna showed that: the tripartite transforming gene of e26 forms a contiguous reading frame of 1046 codons, including 272 gag, 283 mybe, and 491 ets codons. no subgenomic ... | 1984 | 6097027 |
| variations of endogenous chicken proviruses: characterization of new loci of endogenous proviruses in the genome of italian partridge chickens. | the composition and structure of endogenous proviruses present in the genome of italian partridge chickens were studied by the method of blot hybridization using rav-2 [32p]dna or ltr of rsv as hybridization probes. the genomes of 5 out of 39 chickens analyzed did not contain endogenous proviruses related to rav-2. different sets of five so far undescribed endogenous proviruses, differing in the structure and location, were detected in the dna of other ip chickens. none of them is identical in i ... | 1984 | 6097480 |
| [isolation of virus-specific double-stranded rna from cells transformed with rous sarcoma virus]. | several methods were used for isolation of double-stranded (ds) rna from the cytoplasm of rous sarcoma virus-transformed chick embryo cells. the dsrna was shown to have a high melting temperature (82.5 degrees c) in 0.16 m phosphate buffer (ph 6.8), which shifted to more than 90 degrees c after rnase treatment. the size of a single strand was approximately 1300-1600 nucleotides and rnase-resistant fragments were 50-250 nucleotides long. double-stranded rna formed hybrids with the labeled genomic ... | 1984 | 6097811 |
| a non-mhc genetic influence on response to rous sarcoma virus-induced tumors in chickens. | avian-leukosis-free females from regional poultry research laboratory (rprl) inbred lines 6(1) and 7(2) were inseminated with pooled semen from rprl line 15i5 males. the progeny resulting from the two crosses 15i5 x 6(1) and 15i5 x 7(2) were of the b2/b15 major histocompatibility complex (mhc) genotype, the b2 haplotypes from lines 6(1) and 7(2) being indistinguishable. when challenged with rous sarcoma virus (rsv) at 6 weeks of age, 30 out of 31 progeny of cross 15i5 x 6(1) developed tumors tha ... | 1984 | 6098253 |
| enzymatic characteristics of pp60v-src isolated from vanadium-treated transformed cells. | the transforming protein of rous sarcoma virus (rsv) typically appears as a single phosphorylated polypeptide designated pp60v-src. pp60v-src possesses a protein kinase activity specific for tyrosine residues on select protein substrates. treatment of rsv-transformed cells with vanadium ions resulted in the appearance of an electrophoretic variant of pp60v-src and was paralleled by a significant increase in the src kinase specific activity in purified enzyme preparations. both the normal (standa ... | 1984 | 6098587 |
| complete env gene deletions of three replication-defective strains of rous sarcoma virus and a model for the origin of their genetic structures. | replication-defective deletion mutants of rous sarcoma virus (rsv) have been described which transform cells in culture and elaborate envelope (-) defective particles. the env deletions of two clonal variants of the bryan strain of rsv, rsv(-)3, and rsv(-)16, and of a replication-defective variant of schmidt-ruppin rsv (srn8) were analyzed by fingerprinting oligonucleotides hybridized by a molecularly cloned env dna probe that spans from near the 3' end of pol to the 3' end of env. it was observ ... | 1984 | 6100578 |
| inhibition of rous sarcoma-virus-induced transformation by proteins involved in blood coagulation. | plasma, serum and the main proteins involved in the final steps of blood coagulation, fibrinogen, thrombin and plasma transglutaminase, have been tested for their ability to inhibit cell transformation and/or to induce reversion of the transformed to the normal phenotype in rsv-infected chicken embryo fibroblasts. the results obtained show that plasma, and not serum, fibrinogen, when converted to fibrin by thrombin, and activated transglutaminase alone prevent focus appearance and cause reversio ... | 1980 | 6102967 |
| electron microscopic studies on the structure of 60-70s rna of avian myeloblastosis virus. | structural properties of the 60-70s rna complex of avian myeloblastosis virus (amv) were analysed in electron microscope after treatment under a set of non-denaturing, gently and strongly denaturing conditions. by selected denaturing conditions, the significant fraction of 60-70s amv rna molecules revealed partially unfolded structures either in a dimer or a more complex form and in a length corresponding to mol. wt. of 5.6 x 10(6). the typical dimers contained a characteristic central structure ... | 1982 | 6132536 |
| transformation of rat cerebral endothelial cells by rous sarcoma virus. | rat cerebral microvascular endothelial cells were infected with schmidt-ruppin rous sarcoma virus-strain d (sr-rsv-d), an avian retrovirus. a single focus of transformed cells was isolated and the resultant cell line designated rce-t1. the specificity for sr-rsv-d transformation was determined by virus rescue assay and demonstration of virus-specific antigens. rce-t1 cells are virogenic when fused with chicken embryo fibroblasts (cef) and do not produce infectious virus as demonstrated by the ab ... | 1983 | 6134735 |
| respiratory syncytial virus infection in syrian hamsters. i. development of humoral immunity. | adult syrian hamsters have been shown useful for the study of respiratory syncytial virus (rsv) infection. clinical manifestations coincided with the maximum replication of the virus in respiratory tract of infected animals as confirmed by immunofluorescence (if) test. the dynamics of secretory and serum antibody responses is described in infected and reinfected animals. | 1983 | 6140834 |
| respiratory syncytial virus infection in syrian hamsters. ii. regulation of the immune response. | the dynamics of immune cell responsiveness in the process of development of primary and secondary immune responses after infection of adult syrian hamsters with native respiratory syncytial virus (rsv) was studied. in primary immune response, the enhancement of functional responsiveness of lymphocytes to mitogens and the maximum level of their spontaneous proliferative activity were found to precede the optimal level of antibody synthesis. regulation of the dynamics of immunogenesis after reinfe ... | 1983 | 6140835 |
| replication of transformation-defective mutants of the prague strain of rous sarcoma virus and isolation of a td mutant from duck-adapted pr-rsv-c. | the replication of transformation-defective mutants of the prague strain of rous sarcoma virus subgroup c was studied using roller cultures. under such conditions, 10(5)--10(6) infectous units of virus per 0.2 ml were produced, as revealed in both the reverse transcriptase and 16q complementation tests. a new td dapr-rsv-c mutant was isolated from duck-adapted pr-rsv-c. this mutant replicated in roller cultures with equal efficiency as the original td pr-rsv-c. it was verified that td dapr-rsv-c ... | 1980 | 6153995 |
| target antigens for antibodies and complement at the cell surface of rsv-transformed fibroblasts. | using cells transformed by rous sarcoma virus (rsv), an rna tumour virus whose genetic and structural composition is fully known, the virus-induced surface antigens acting as targets for antibodies and complement were studied. among the virus structural proteins, only the envelope antigen gp85, but not the core group-specific proteins or reverse transcriptase, were able to mediate immune lysis in the 51cr-release assay. the group-specific antigenic determinants of gp85 were predominantly involve ... | 1980 | 6155325 |
| interaction between cellular and viral genes in the expression of the rsv-induced transformation-specific cell-surface antigen vcsa. | transformation of bhk hamster fibroblasts by an env- strain of rous sarcoma virus (rsv) leads to the appearance at the cell surface of a virus-induced nonvirion antigen (vcsa), specific for transformation, whose expression is controlled by the transforming src gene. previous work has shown that a rabbit anti-vcsa serum lyses specifically, in the presence of complement, 51cr-labelled rsv-transformed cells from different animal species. now, by competition experiments with a panel of different unl ... | 1980 | 6156133 |
| transformation by rous sarcoma virus: a cellular substrate for transformation-specific protein phosphorylation contains phosphotyrosine. | transformation of chicken embryo fibroblasts by rous sarcoma virus (rsv) is caused by a single viral gene, src, which encodes a phosphoprotein, pp60src, with the enzymatic activity of a protein kinase. the relative abundance of a 36,000 molecular weight (36k) phosphorylated polypeptide which can be detected by two-dimensional electrophoresis of 32p-labeled phosphoproteins is greatly increased in rsv-transformed fibroblasts. we have reported previously that phosphorylation of the 36k polypeptide ... | 1980 | 6159984 |
| interferon production by human mononuclear leukocytes: differences between respiratory syncytial virus and influenza viruses. | the ability of respiratory syncytial virus (rsv) to induce interferon production by human mononuclear leukocytes was compared with that of influenza viruses. cell culture fluids were assayed for interferon activity 1, 3 and 7 days after exposure to rsv or to one of two subtypes of influenza a virus (h0n1 and h3n2). rsv induced interferon production inconsistently and in low titers. varying the multiplicity of infection did not improve the ability of rsv to induce interferon production. in contra ... | 1981 | 6163726 |
| evidence for a gp85-related glycoprotein in cells transformed by the bryan high titer strain of rous sarcoma virus. | the bryan high titer strain of rous sarcoma virus (bh-rsv) is a deletion mutant in the env-gene coding for the viral envelope glycoproteins gp35 and gp85. in this report experimental evidence is described that cells, transformed by bh-rsv, express a glycoprotein immunologically related to gp85. animals bearing bh-rsv induced tumors produce antibodies reacting with gp85 of nondefective rsv. lysates of a bh-rsv transformed quail cell line, r(-):q, inhibit the immunoprecipitation of gp85 by antibod ... | 1981 | 6168244 |
| a mouse homolog to the avian sarcoma virus src protein is a member of a protein kinase cascade. | recent work has identified a cascade of membrane bound protein kinases in ehrlich ascites tumor cells. these enzymes, designated pkl, pks and pkm, are present in both ehrlich tumor and mouse brain, but the cascade is active only in the tumor tissue. we have now purified a fourth protein kinase, pkf, that is also associated with this cascade. protein kinase f prosphorylates pkl and is phosphorylated by pks. the position of this kinase in the cascade is as follows, where the arrows denote phosphor ... | 1981 | 6168390 |
| the development of respiratory syncytial virus-specific ige and the release of histamine in nasopharyngeal secretions after infection. | we studied the development of respiratory syncytial virus (rsv)-specific ige and the release of histamine in nasopharyngeal secretions from 79 infants with various forms of respiratory illness due to rsv. rsv-ige was measured by an enzyme-linked immunosorbent assay; specificity was confirmed by appropriate blocking experiments. histamine content in the secretions was determined by fluorimetric methods. rsv-ige was detectable in only one of 19 patients with rsv infection without wheezing, but was ... | 1981 | 6168908 |
| mouse fibroblasts transformed by rous sarcoma virus express a virus-specific non-virion transplantation antigen. | rous sarcoma virus (rsv)-transformed fibroblasts from different animals species a serologically detectable virus-induced non-virion cell surface antigen (vcsa), whose expression is controlled by the transforming viral src gene and by a cellular gene. now, by in vivo immunization, we have found that rsv-transformed fibroblasts from different mouse strains share a virus-specific transplantation antigen. in fact, only animals immunized with irradiated syngeneic or allogeneic fibroblasts transformed ... | 1981 | 6169669 |
| [production of noninfectious virions of the rous sarcoma virus by virogenic hamster cells]. | noninfectious virions morphologically identical with avian type c virus virions were produced in rous sarcoma virus-transformed virogenic hamster cells. the population of the virions contained the major internal protein of avian oncornavirus. it is assumed that production of defective rsv virions occurred in the cells. the major internal protein of avian oncornaviruses was found to be incorporated into the virions containing in their membrane interspecies antigens of hamster oncornavirus produce ... | 1981 | 6171103 |
| tumor promoters alter gene expression and protein phosphorylation in avian cells in culture. | we have investigated the effect of 12-o-tetradecanoylphorbol 13-acetate (tpa) on the synthesis and modification of polypeptides in normal avian cells and cells infected by wild-type and temperature-sensitive rous sarcoma virus (rsv). using two-dimensional gel electrophoresis, we have detected alterations in both the abundance of cellular polypeptides and in their phosphorylation that seem unique to tpa treatment. however, the state of phosphorylation of the major putative substrate for the actio ... | 1981 | 6171814 |
| in vitro differentiation of chicken embryo skin cells transformed by rous sarcoma virus. | the epidermal cells isolated from 14-day chicken embryo shank skin epidermis were infected in vitro with rous sarcoma virus (rsv). within a few weeks, rapidly growing colonies of epithelial cells appeared among the sea of transformed fibroblastic cells. when isolated and subcultured, these cells were found to possess typical markers of skin epidermis. the presence of major keratin and typical epithelial cell type morphology strongly suggested that these cells were transformed epidermal cells ret ... | 1981 | 6172432 |
| rous sarcoma virus mutant la3382 is defective in virion glycoprotein assembly. | la3382 is a temperature-sensitive replication-defective mutant of rous sarcoma virus that contains four active mutations. in this study we performed experiments to determine the biochemical defect that blocks the synthesis of infections virus late in the replication cycle. at the nonpermissive temperature (41 degrees c) cells infected with la3382 synthesized virus particles which were noninfectious and exhibited significant reductions in the amounts of gp85 and gp37 present in the virions. an an ... | 1981 | 6172600 |
| similarities and differences between the effects of epidermal growth factor and rous sarcoma virus. | we have derived a line of a431 human tumor cells infected with rous sarcoma virus (rsv). the infected cells contain the rsv-transforming protein, pp60src, which has characteristic tyrosine specific protein kinase activity. as in other rsv-transformed cells, a 36,000-dalton protein is phosphorylated in rsv-infected a431 cells. addition of epidermal growth factor (egf) to the cells induces further phosphorylation of this protein. in contrast, this phosphoprotein is not detected in uninfected a431 ... | 1981 | 6173387 |
| dissection of the antigenic determinants expressed on the cell surface of rsv-transformed fibroblasts by monoclonal antibodies. | fusion of p3/x63-ag8 mouse myeloma cells with splenocytes obtained from mice hyperimmunized with a bhk hamster fibroblast line transformed by an env-strain of rous sarcoma virus (rsv) resulted in the production of antibody-secreting hybridomas. seven hybrid clones secreted antibodies binding to rsv-transformed bhk fibroblasts but not to the parental control non-transformed line. the antibodies produced by three of these clones did identify antigenic determinants expressed also on bhk cells trans ... | 1982 | 6177648 |
| participation of subgenomic retroviral mrnas in recombination. | envelope glycoprotein (env) mrna from avian retroviruses was injected into cells transformed by env-deleted bryan rous sarcoma virus [rsv(-)]. the genetic deficiency of rsv(-) was complemented, and infectious transforming virus was released for many days after these injections. the long-term activity of the injected env mrna is believed to be due to reverse transcription of the injected rna after its incorporation into virus particles. the resulting subgenomic provirus, presumed to be integrated ... | 1982 | 6178841 |
| discrete primary locations of a tyrosine-protein kinase and of three proteins that contain phosphotyrosine in virally transformed chick fibroblasts. | we have studied the localization of three abundant cellular proteins which are substrates for tyrosine protein kinases in virally transformed chicken embryo fibroblasts. the primary location of each substrate is unaltered by transformation with rous sarcoma virus (rsv). the tyrosine-phosphorylated species is localized with the nonphosphorylated species. two of the proteins, of about 46,000 and 28,000 daltons, have a similar location. they are present in the high speed supernatant of cells homoge ... | 1982 | 6179948 |
| interferon inhibits establishment of fibroblast infection with avian retroviruses. | pretreatment of chick embryo fibroblasts (cef) with low doses of homologous interferon (16 u/ml) drastically inhibits cell transformation by, and replication of rous sarcoma virus (rsv). treatment of chick cells with 16 u/ml of interferon before de novo infection with a transformation defective (td) mutant-rsv, also resulted in a reduction of extracellular virus particles. this was determined by infectivity titrations, virus associated reverse transcriptase (rt) activity and measurement of metab ... | 1982 | 6180104 |
| cells transformed by a wide variety of agents express higher abundance levels of some cellular rna species. | a cdna-cloned library was prepared from mrna synthesized by sv40-transformed mouse cells. eleven cdna clones were selected based on their ability to hybridize higher levels of mrna in sv40-transformed 3t3 cells than in 3t3 cells. these cdna clones were employed to screen the steady-state levels of cytoplasmic rnas in a wide variety of viral (sv40, polyoma, adenovirus, and rous sarcoma virus) and nonviral (methylcholanthrene, embryonal carcinoma) transformed cell lines. two of the cdna clones--a1 ... | 1982 | 6185512 |
| molecular events leading to fusiform morphological transformation by partial src deletion mutant of rous sarcoma virus. | a mutant of the prague strain of rous sarcoma virus (rsv) has two deletions near the 5'-terminus of its src gene. the mutant (dl 5) induced fusiform morphological transformation in chick embryo fibroblasts (cef) in contrast to the round type morphological transformation induced by wild type (wt) rsv. the partially deleted src of dl5 was shown to code for a 52k protein which has tyrosine kinase activity as high as that of p60src. in dl 5-transformed cells, a 36k protein was heavily phosphorylated ... | 1983 | 6188271 |
| transcriptional control of the fibronectin gene in chick embryo fibroblasts transformed by rous sarcoma virus. | rous sarcoma virus transformed-chick embryo fibroblasts contain decreased amounts of the adhesive protein fibronectin that results from a lowering of fibronectin mrna levels (fagan, j.b., sobel, m.e., yamada, k.m., de crombrugghe, b., and pastan, i. (1981) j. biol. chem. 256, 520-525). in the present study, nuclei isolated from chick embryo fibroblasts (cef) and rous sarcoma virus transformed-chick embryo fibroblasts (rsv-cef) were used to measure relative rates of fibronectin rna synthesis. [32 ... | 1983 | 6189838 |
| transformation parameters and pp60src localization in cells infected with partial transformation mutants of rous sarcoma virus. | rous sarcoma virus (rsv)-induced transformation is mediated by the action of the viral src gene product pp60src. this transforming protein is found at several cytoplasmic locations, including the adhesion plaques of rsv-transformed cells. in these studies, we have focused on the adhesion plaque location of pp60src and determined whether any of the induced transformation parameters correlate with the presence of pp60src in the adhesion plaques. a series of partial transformation mutants of rsv th ... | 1983 | 6190075 |