inhibition of oncornavirus functions by 2'-azido polynucleotides.the 2'-azido analogs of poly(u) and poly(c), poly(duz) [poly(2'-azido-2'-deoxyuridylic acid)], and poly-(dcz [poly(2'-azido-2'-deoxycytidylic acid)], were found to inhibit the rna-directed dna polymerase (reverse transcriptase) activity of murine leukemia (moloney, rauscher) and sarcoma (moloney) virus, and feline leukemia (theilen) and sarcoma (gardner) virus, while under the same conditions the unsubstituted parent compounds failed to do so. in addition, poly(duz) and poly(dcz) inhibited the r ...197547174
studies on virus induction by 5-bromodeoxyuridine in nonproducer murine sarcoma virus-transformed 3t3 cells. 197549978
immunity to murine sarcoma virus induced tumours. iv. direct cellular cytolysis of 51cr labelled target cells in vitro and analysis of blocking factors which modulate cytotoxicity.the antigen specific cell mediated cytotoxicity of msv immune spleen lymphocytes to 51cr labelled murine lymphoma cells was wholly abolished by pretreatment of the spleen cells with anti-theta antibody and complement. early during the immune response to msv the cytotoxic acitivity was inhibited by incubation of immune lymphocytes with "late progressor" or "early regressor" serum. immune lymphocytes at later times were more refractory to such inhibition by serum blocking factors. although unfract ...197550851
partial characterization of c-type particles in a cell line (wr-9) derived from a rat epidermoid carcinoma of spontaneous origin.a c-type virus continuously released from a cell line (wr-9) derived from a spontaneous epidermoid carcinoma was purified by means of large-scale tissue culture techniques and high-volume zonal centrifuges. with the use of relatively pure virus concentrates, partial characterization of the virus has been accomplished. up to 60 liters of spent culture medium from relatively low virus-yielding cultures were processed at a time through the model k ultracentrifuge in order to obtain quantities of vi ...197550883
species and interspecies radioimmunoassays for rat type c virus p30: interviral comparisons and assay of human tumor extracts.the major internal protein, p30, of rat type c virus (ralv) was purified and utilized to establish intra- and interspecies radioimmunoassays. three rat viruses were compared in homologous and heterologous intraspecies assays with no evidence of type specificity. the only heterologous viruses to give inhibition in these species assays were the feline (felv) and hamster (halv) type c viruses; these reactions were incomplete and required high virus concentrations. an interspecies assay using a goat ...197554444
sequence homology between moloney murine sarcoma virus and moloney leukemia virus rna.the moloney murine sarcoma-leukemia virus [m-msv (mulv)], propagated at high multiplicity of infection (moi), was demonstrated previously to contain a native genome mass of 4 x 10(6) daltons as contrasted to a mass of 7 x 10(6) daltons for moloney murine leukemia virus (m-mulv). the 4 x 10(6)-dalton classof rna from m-msv (mulv) was examined for base sequence homology with dna complementary to the 7 x 10(6)-dalton m-mulv rna genome. approximately 86% of the m-msv (mulv) was protected from rnase ...197659817
immunological properties of murine thymus-dependent lymphocyte surface glycoproteins.the immunological properties of two murine thymus-dependent (t) lymphocyte surface glycoproteins, t200 and t25, were investigated. t200 is a lymphocyte-specific antigen with a high degree of species specificity. it shares antigenic determinants with molecules present on thymus-independent (b) lymphocytes. t25 has antigenic determinants which cross-react with antigens on mouse brain, rat thymocytes and rat brain. an antiserum against a purified rat brain glycoprotein which carries thy-1.1 reacts ...197661878
phosphorylation and nucleic acid binding properties of m1 moloney murine sarcoma virus-specific pp60gag.the pp60gag polyprotein of the feline leukemia virus pseudotype of m1 moloney murine sarcoma virus [m1msv(felv)] was previously shown to be msv specific and to contain murine p30 and smaller structural polypeptides. this protein was detected in m1msv-transformed cells, and in pulse-chase studies it was found to be stable. in this study virion p60 was shown to contain murine pp12, to be phosphorylated, and to bind to nucleic acids. 32p-labeled m1msv[felv) was fractionated by guanidine agarose chr ...197769721
isolation of a type c rna virus from an established human histiocytic lymphoma cell line.a type c rna virus has been detected in the culture fluids of the su-dhl-1 human histiocytic lymphoma cell line previously established in this laboratory. in electron micrographs, the virus closely resembled other typical mammalian type c rna tumor viruses in size and morphology. viral rna-dependent dna polymerase activity has been demonstrated in particles (densities of 1.15 and 1.22 g/ml) in the microsomal cytoplasmic fraction and in pellets of culture fluids. the enzyme is partially inhibited ...197770039
lack of expression of type c hamster virus after neoplastic transformation of hamster embryo fibroblasts by benzo(a)pyrene.syrian hamster embryo fibroblasts transformed in vitro with benzo(a)pyrene were analyzed for the presence of type c viral components, including extra- and intracellular reverse transcriptase activity, intracellular type c hamster virus-related rna, and cellular hamster virus group-specific antigen. no evidence could be obtained for the presence of any of these components, although they were easily detectable in hamster fibroblasts producing either b-34 virus (a hamster virus pseudotype of harvey ...197771196
secondary in vitro generation of cytolytic t-lymphocytes (ctl's) in the murine sarcoma virus system. virus-specific ctl induction across the h-2 barrier.following in vitro stimulation of murine sarcoma virus moloney isolate (m-musv)-immune spleen cells with syngeneic antigenically related moloney leukemia cells, highly efficient cytotoxic t-lymphocytes (ctl's) were generated. the cytotoxic effect was directed only against h-2-compatible target cells bearing m-musv tumor-associated antigens (taa). however, in a cold target competition assay a weak but detectable capacity to block ctl activity was also obtained when allogeneic moloney leukemia cel ...197880457
interruption of oncornavirus replication by modified rifamycin antibiotics.thirteen rifamycin sv derivatives containing 3'-alkylaminomethyl substituents fail to inhibit the activities of the simian sarcoma virus type 1 dna polymerase, and of cellular dna, rna, and poly(a) polymerases prepared from nih swiss mouse embryos. these compounds show a range in their toxicities for nih swiss mouse 3t3 cells and in their capacities to inhibit production of foci of morphologically altered cells by murine sarcoma virus (msv). three compounds--the n-methyl-n-hydroxyethylaminomethy ...197781643
inhibition of murine sarcoma virus-induced foci formation by cytidine analogues and other drugs chemotherapeutically effective in human malignancies.the present report describes an in vitro culture system using the kirsten murine sarcoma virus transformation focus assay to evaluate the antiviral activities of 12 commonly used chemotherapeutically effective drugs. since these drugs are cytotoxic, the plating efficiencies of the cells treated were monitored simultaneously. using this procedure, adriamycin, daunorubicin, bleomycin camptothecin, mithramycin, hydroxyurea, 5-fluorouracil, thioguanine, 9-beta-d-arabinofuranosyladenine, 1-beta-d-ara ...197988425
inhibition of spontaneous transformation of rat embryo cells releasing endogenous type c virus by virus-specific antiserum.noninbred sprague-dawley rat embryo cell clones predictably undergo transformation after 20-30 in vitro passages following spontaneous release of endogenous rat leukemia virus (ralv). in the presence of ralv-specific antiserum, virus production and infectivity were reduced and transformation was delayed from 6 to 25 weeks. transformation was not associated with an increased expression of kirsten murine sarcoma virus-related src gene rna.197989211
analysis of proteins of mouse sarcoma pseudotype viruses: type-specific radioimmunoassay for ecotropic virus p30's.murine sarcoma virus pseudotypes were prepared by infection of nonproducer cells (a1-2), which were transformed by the gazdar strain of mouse sarcoma virus, with gross (n-tropic), wn1802b (b-tropic), or moloney (nb-tropic) viruses. the respective host range pseudotype sarcoma viruses were defined by the titration characteristics on cells with the appropriate fv-1 genotype. proteins from virus progeny were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. bands present in bot ...197990164
[biochemical characteristics of a calf leukemia virus in chronically infected cells].studied were the conditions of cultivation of flk cells chronically infected with a calf leucosis virus. the gradient values of density were compared to those of the murine sarcoma virus--1.14--1.15 vs, 1.17--1.18/cm3. established were the parameters of the reverse transcriptase reaction for the calf leukosis virus (magnesium-dependent reverse transcriptase). data showed that the calf leucosis virus may not resolutely be referred either to the b- or the the c-type of retroviruses.197992095
suramin: a potent inhibitor of the reverse transcriptase of rna tumor viruses.suramin--a well-known antitrypanosomal agent--was found to exert a strong inhibitory effect on the rna-directed dna polymerase (reverse transcriptase) activity of several oncornaviruses such as moloney murine leukemia virus, murine rauscher leukemia viruses, moloney murine sarcoma virus and avian myeloblastosis virus. inhibition of enzyme activity was obtained with both endogenous viral rna and (a)n . oligo(dt) as the template-primer. suramin effected a 50% inhibition of the reverse transcriptas ...197992362
inhibition of proliferation of lymphoma cells and t lymphocytes by suppressor cells from spleens of tumor-bearing mice.we have recently demonstrated suppressor cells in spleens of mice bearing tumors induced by moloney murine sarcoma virus (msv) which were non-t cells and inhibited phytohemagglutinin molney (pha)-induced dna synthesis of syngeneic normal spleen cells. from the present study, the suppressor cells appeared to be macrophages since they were radioresistant, inactivated by carrageenan, and removed by adherence columns and an iron/magnet technique. we have also found that suppressor cells were still f ...1975122986
the pathology of brain tumors induced by murine sarcoma virus, moloney strain.murine sarcoma virus, moloney strain, was inoculated intracerebrally into 75 spraque-dawley rats within 24 hours after birth. of 48 rats examined histologically within 35 days after virus inoculation, most developed granulomatous lesions in the meninges or in the cortex and in the glial nodules of the subependymal region, or in all these regions. the granulomatous lesions first appeared 8 days after virus inoculation and reached a peak about 30 days after virus inoculation. thereafter, the lesio ...1976137651
suppressor t cells regulate the cytolytic t lymphocyte response to syngeneic tumors induced by murine sarcoma virus (msv) in the mouse.studies were designed to analyze the immune activities of spleen cells from mice previously injected with murine sarcoma virus (msv) and undergoing the processes of msv tumor growth and rejection. fractionation of msv-primed spleen cells according to cell size by velocity sedimentation at unit gravity showed that msv-specific cytolytic t lymphocytes (ctl) generated in vivo underwent an apparent transition in size from large to small cells as the tumor regressed. the majority of ctl precursors, h ...1979156765
virus-specific dna sequences in mouse and rat cells transformed by the harvey and moloney murine sarcoma viruses detected by in situ hybridization. 1975163051
phosphoproteins: structural components of oncornaviruses.oncornaviruses, which contain a virion-associated protein kinase, were found to possess phosphoproteins as virion structural components. one major phosphoprotein common to strains of laboratory and wild mouse oncornaviruses and a strain of feline leukemia virus was shown to be a polypeptide of about 12, 000 mol wt. in addition to this, the kirsten strain of murine sarcoma virus contained a second major phosphoprotein of about 10, 000 mol wt, and mouse erythroblastosis virus contained a second ma ...1975163371
a comparison of the effects of daunomycin and adriamycin on various dna polymerases.the effects of the anthracycline antiboties, daunomycin and adriamycin, on the dna-directed activities of dna polymerases from murine sarcoma virus, rat liver (high-molecular-weight species), escherichia coli, and micrococcus luteus were determined. under all conditions tested, these compounds had greater inhibitory effect against the viral polymerase than against cellular polymerase. the inhibition of murine sarcoma virus dna polymerase by daunomycin was competitive with respect to dna. for vir ...1975163690
studies of fbj osteosarcoma virus in tissue culture. ii. autoinhibition of focus formation.a high-titered non-focus-forming virus, fbj-mulv (murine leukemia virus), present in fbj tumor preparations, inhibited significantly the expression and production of fbj-musv (murine sarcoma virus) in tissue culture. this "autoinhibition" was comparable to that observed when a 3- to 4-log excess of infectious mulv was added to standard musv. the degree of inhibition was influenced by the tropism of the mulv (or the ease of spread and propagation of mulv in certain cells), multiplicity of infecti ...1975164561
aberrant viruses in cells infected with murine sarcoma virus-feline leukemia virus.this study describes an unusual type of virus seen when a feline leukemia virus (felv) pseudotype of murine sarcoma virus (musv) obtained by cocentrifugation procedures infected feline embryo cells (fef) and two crandell cat cell lines (crfk1, crfk2). when all three cell cultures were infected with musv-felv, only fef and crfk2 were transformed and only these showed normal and aberrant virus. the crfk1 infected with musv-felv did not transform but did replicate normal type-c virus with a 50-a in ...1975164569
distribution of membrane particles and gap junctions in normal and transformed 3t3 cells studied in situ, in suspension, and treated with concanavalin a.freeze-fracture techniques were used to study the ultrastructural distribution of plasma membrane particles in cultures of normal balb/c and swiss 3t3 and simian virus 40- or murine sarcoma virus-transformed fibroblasts. no apparent differences were observed. cultures fixed in situ show a seemingly random distribution of membrane particles both in normal or in transformed cells. treatment of cell cultures in situ with concanavalin a does not result in an altered pattern of particle distribution. ...1975164659
non-producer human cells induced by murine sarcoma virus.non-produces (np) human cells were isolated from transformed foci induced by the kirsten mouse sarcoma virus. these morphologically altered np cells produced neither infectious virus nor complement-fixing antigens of the murine sarcoma-leukemia virus complex. however, the sarcoma virus genome could be rescued from these nf cells by co-cultivation with cells carrying "helper" kirsten mouse leukemia virus or woolly monkey leukemia virus. the possible usefulness of these cells in efforts designed t ...1975165148
effect of protease inhibitors on focus formation by murine sarcoma virus.the effect of six protease inhibitors, isolated from various species of actinomycetes, on focus formation by murine sarcoma virus was examined. pepstatin was the only inhibitor. the treatment of cells with pepstatin at various times possibly retards the early stage of infection with murine sarcoma virus.1975165316
development of a 3t3-like line from an embryo culture of an inbred strain of syrian golden embryo culture of an inbred strain of syrian hamster developed into a permanent cell line under the "3t3" 3 x 10-5 cells/60-mm dish. the resulting cell line had properties very similar to those of the mouse 3t3 series and was named hams 3t3. the cell showed density-dependent inhibition of division with a saturation density of 1.0 to 1.2 x 10-6 cells/60-mm dish or 4.5 to 5.5 x 10-4 cells/sq cm. addition of fresh medium containing 5 or 10% fetal calf serum to a confluent culture induced dna syn ...1975165885
large round cell granulomas induced by murine sarcoma virus (moloney) in mouse brains.the effect of murine sarcoma virus of moloney strain on central nervous system was examined morphologically in swiss mice of different age. a single intracranial inoculation of cell-free virus solution resulted in the induction of characteristic intracerebral granulomas in 82.8% of the newborn to 5 day-old group, in 71.4% of the 6 to 10 day-old group, and in 68.0% of the 11 to 20 day-old group. the mean latency periods to tumor recognition were 16.5, 21.1, and 33.5 days, respectively. the granul ...1975128993
secondary cell-mediated cytotoxic response to syngeneic mouse tumor challenge.when c57bl/6 mice previously immunized with murine sarcoma virus (msv) were challenged with a rauscher virus-induced lymphoma, rbl-5, a secondary cell-mediated cytotoxic response could be detected by the cr release cytotoxicity assay. the level and distribution of the secondary cytotoxic response was affected by the route of challenge. animals injected i.p. demonstrated a high level of cytotoxicity in the peritoneal exudate cells 3 days after challenge and subsequently cytotoxicity was detected ...1975168259
murine sarcoma virus pseudotypes acquire a determinant specifying n or b tropism from leukaemia virus during rescue. 1975168499
transformation of cultured rat liver cells by murine sarcoma viruses.cultured liver cells (trl-2 cells), originating from a bd-6 rat, an inbred black rat strain, and possessing several marker enzymes, and characteristic ultrastructures of hepatic cells, were infected with murine sarcoma viruses (msv: kirsten and gazdar strains). on day 5-6 after virus inoculation, the monolayered epithelial cells focally began to pile up forming small polypoid projections, and on day 7 round-shaped cells were released from the polypoid foci. these cells first grew in a chain or a ...1975169808
human amnion and lung tissue culture systems for possible detection and study of human rna tumor viruses.a human lung and an amnion cell line were identified as highly susceptible to transformation by the rhabdomyosarcoma-114 (rd-114) virus pseudotype of murine sarcoma virus (msv). msv transformation on these two cell lines demonstrated a) "one-hit" kinetics with an msv stock which contained a 100-fold excess of msv over its detectable associate rd-114 helper virus and b) only a slight increase (2x) in focus-forming titers by the addition of optimal concentrations of rd-114 helper virus. these find ...1975169818
control of reversion of moloney virus sarcoma virus transformed cells.mouse cells transformed by the moloney murine sarcoma virus (msv) native to the species can give rise to revertants which are supersusceptible to a second cycle of transformation. the msv retransformed cells can give rise to several complex functional states even after several cycles of cloning: a) formation of sarcoma positive, leukemia negative (s+lminus) type cells of which some sublines may be inducible for msv by halogenated pyrimidines; b) detection of initially sminuslminus cells which sp ...1975169824
in vivo interactions between murine leukemia and sarcoma viruses.experiments have been performed with the aim of elucidating the nature and the extent of the in vivo interactions between murine leukemia viruses (mulvs) and murine sarcoma virus (msv). balb/c and cba mice, injected neonatally with graffi or passage a gross viruses (mulv-gi, mulv-g), have been inoculated as young adults with murine sarcoma virus, moloney strain (msv-m). a higher percentage of nonregressing sarcomas appeared in these animals, sometimes accompanied simultaneously by leukemia. the ...1975169829
genetic control of oncogenesis by murine sarcoma virus moloney pseudotype. i. genetics of resistance in akr mice.infection of moloney mouse sarcoma virus (m-msv) in adult mice of several inbred strains revealed that all strains except akr are highly susceptible to m-msv tumor development. f1 hybrids between akr and cba, dba/2 or nih mice are as resistant (93%) as the parental akr strain, which indicates that resistance is transmitted as a dominant character. first backcross mice to the susceptible parent show a 3:1 ratio of resistant to susceptible mice. this is the expected ratio for two segregating loci ...1975170219
genetic control of oncogenesis by murine sarcoma virus moloney pseudotype. ii. a dominant epistatic susceptibility gene.we have shown in the preceding paper that akr mice are highly resistant to m-msv tumor development, and that resistance is transmitted as a dominant character. in the present studies the tumor-response pattern of f1 hybrids between resistant akr and susceptible strains (c57bl/6, balb/c and b10br) following injection with moloney mouse sarcoma virus (m-msv) resembles that of the non-akr parent. segregation is observed in first backcross (bc1) and f2 mice, and the segregation ratios up to bc3 mice ...1975170220
clonal variation of the mouse cells in the endogenous c-type virus induction by 5-iodo-2'-deoxyuridine.using an mlg cell line originating from a single newborn ddy mouse, n-tropic c-type virus able to infect the cells or origin was induced by 5-iodo-2'-deoxyuridine (iudr). all the clones isolated from the mlg cell line released the virus after iudr-treatment. there was more than a 100-fold difference in the virus inducibility between the highly and lowly inducible clones. the [125i]iudr incorporation was, however, the same for the both types of clones. when the induced virus was titrat-d in the s ...1975170368
murine xenotropic type c viruses i. distribution and further characterization of the virus in nzb mice.the xenotropic mouse type c virus, originally detected in cultured embryo cells from new zealand black (nzb) mice, has been recovered from over 50 adult nzb animals and 15 nzb embryos. its presence is best detected by measuring its ability to rescue a murine sarcoma virus (msv) genome from a non-virus-producing msv-transformed rat cell. the virus can serve as a helper for replication of msv. it has a distinct type-specific coat and is a prototype for a third serotype of mouse type c viruses, nzb ...1975170419
adaptation of n-tropic friend leukaemia virus and its murine sarcoma virus pseudotype of non-permissive b-type c57bl/6 mouse cell line.n-tropic friend leukaemia virus (flv) was serially passaged in a b-type c57bl/6 mouse cell line, yh-7. after a single passage, the infectious efficiency of flv in the restrictive yh-7 cells was significantly increased. this adapted character of flv could be reversed by a single passage in permissive n-type mlg cells. the true host range conversion from n to nb was accomplished after eleven to twelve passages in yh-7 cells. in contrast, the host range conversion of n-tropic murine sarcoma pseudot ...1975171332
two levels of restriction by mouse or cat cells of murine sarcoma virus coated by endogenous xenotropic oncornavirus.mouse and cat cells were each examined for the mode of restriction of endogenous xenotropic oncornavirus. murine xenotropic helper virus (mux) and its pseudo-type of moloney murine sarcoma virus (msv(mux)) were grown in cat cells to high titre. mux alone did not replicate in any mouse cell tested including normal or transformed outbred swis 3t3 cells or sc-i cells, but did grow in a variety of other mammalian cells. msv(mux) was not able to achieve that intracellular state from which it could be ...1975171336
inhibition of in vitro growth of lymphoma cells by macrophages from tumor-bearing mice.spleen cells from c57bl/6 mice bearing primary tumors induced by the moloney strain of murine sarcoma virus (musv) strongly inhibited the uptake of tritiated thymidine (3h-tdr) by rbl-5 lymphoma cells in a 48-hour growth-inhibition assay (gia). this activity was first detected 7 days after musv was injected; it peaked at 14 days, and was usually no longer detectable after 18-21 days. it could be detected at effector cell/target cell ratios between 20:1 and 5:1, at which normal spleen cells had a ...1975171434
requirement for cellular protein synthesis in reversal of ethidium-bormide-induced inhibition of cell transformation by murine sarcoma virus.cultures of mouse balb 3t3 fibroblasts exposed to a noncytotoxic dose of ethidium bromide for 16-18 hr are unable to produce foci after infection with murine sarcoma virus. such cultures regain susceptibility to infection when incubated for 6-8 hr in drug-free growth medium. pretreated but not untreated cultures exhibit sensitivity toward brief (6 hr) exposure to cycloheximide, chloramphenicol, and actinomycin d before infection. pretreatment with cordy-cepin inhibits the ability of cultures to ...1975172904
tumorigenicity of virus-transformed cells in nude mice is correlated specifically with anchorage independent growth in vitro.clonal isolates of mouse 3t3 cells and primary rat embryo cells, recovered nonselectively after infection by simian virus 40 (sv40), have been tested for tumorigenicity in the immune-deficient nude mice in order to determine the cellular growth properties in vitro specifically correlated with neoplastic growth in vivo. in addition, mouse 3t3 cells transformed by murine sarcoma virus (musv, kirsten strain), and revertants isolated from cells fully transformed by either sv40 or musv were also stud ...1975172908
radiation-enhanced murine sarcoma virus genome rescue activity.although the doses of x-ray (312-2,500 r) used for irradiation of cells caused impairment of dna synthesis and cell replication, co-cultivation of x-irradiated mulv- carrier cells with un-irradiated nonproducer cells of msv-induced tumour resulted in as much as 20-fold increase in msv retrieval compared with the un-irradiated control. the enhancement was apparent also as a 3-fold increase in the number of cells producing msv (infectious centers) in the co-cultivation plate. this suggested that t ...1975173498
'glioblastoma'. induction of a reproducible autochonous tumor in rats with murine sarcoma virus.inoculation of 0.02 ml of high-titer kirsten strain murine sarcoma virus into the brains of 10-day-old wistar/furth rats yields, with 100 percent incidence, a uniform glioblastoma-like tumor within 16 days. light and electronmicroscopy confirmed the neuroectodermal origin of the parenchymal cells. the remarkable vascular component was studied with extracellular tracers. the permeability of the abnormal endothelium to constituents of the blood vascular compartment was confirmed. accessory vascula ...1976174026
a defined subgenomic fragment of in vitro synthesized moloney sarcoma virus dna can induce cell transformation upon transfection.the longest dna molecules synthesized by endogenous reverse transcription in detergent-permeabilized moloney murine sarcoma virus (mo-msv) virions (clone g8-124) are double-stranded dna molecules of 5,8 kilobase pairs (kbp). this dna species has been purified by sedimentation of total in vitro synthesized mo-msv dna through neutral sucrose gradients. a physical map of the positions of the cleavage sites for a series of restriction endonucleases has been derived for this 5.8 kbp dna. mo-msv dna s ...197984715
further evidence for deletion of envelope glycoprotein (gp69/71) sequences in formation of moloney-murine sarcoma virus.moloney-murine sarcoma virus (s+l- strain of m-msv) has been nonproductively cloned in murine and non-murine host cells (s+l- cells) and the expression of moloney leukaemia virus (m-mulv) 30000 mol. wt. core protein (p30) and envelope glycoprotein (gp69/71) were studied by radioimmunoassay. antigenic determinants of the m-mulv p30 were associated with the sarcoma virus genome in these non-productively transformed cell clones studied, while the determinants of m-mulv gp69/71 were not. the absence ...197880447
[in vitro transmission of mouse leukemia virus to restrictive mouse cells: necessity for mixed infection by two different leukemia viruses].the plaque formation of murine leukemia virus (mulv) in non permissive mouse cells (n-tropic mulv in b-type cells, or b-tropic mulv in n-type cells) was increased by murine sarcoma virus whose plaque-forming activity was extremely low (musv xc-). the infection of n-tropic mulv in b-type cells was increased by musv xc- propagated only in n-type cells but not in b-type cells, and the infection of b-tropic mulv in n-type cells by musv xc- propagated only in b-type cells but not in n-type cells.1975174827
a replication-defective variant of moloney murine leukemia virus. i. biological characterization.we have studied the virus produced by a clone, termed 8a, that was isolated from a culture of murine sarcoma virus-transformed mouse cells after superinfection with moloney murine leukemia virus (mulv-m). clone 8a produced high levels of type c virus particles, but only a low titer of infectious murine sarcoma virus and almost no infectious mulv. when fresh cultures of mouse cells were infected with undiluted clone 8a culture fluids, they released no detectable pogeny virus for several weeks aft ...197874421
preliminary evidence for novel fucose-containing lipids in normal and murine sarcoma virus-transformed rat cells. 1976175795
search for oncogenic viruses in human prostate cancer.electron microscopic, immunologic, and biochemical methods have been used in an attempt to detect and characterize oncornaviruses in human prostatic carcinoma (pca) and benign prostatic hyperplasia (bph), and in prostates of mice of high and low mammary cancer or leukemia strains. ultrastructural examination of 37 pca and nine bph specimens has revealed the presence of particles resembling type c virus in five cases of pca and one of bph, and also two different types of intracisternal virus-like ...197768817
the murine sarcoma virus-induced tumor: exception or general model in tumor immunology? 197766859
rat sequences of the kirsten and harvey murine sarcoma virus genomes: nature, origin, and expression in rat tumor rna.two murine sarcoma viruses, the kirsten and the harvey, were isolated by passage of mouse type c leukemia viruses through rats. these sarcoma viruses have genomes containing portions of their parental type c mouse leukemia virus genomes, in stable association with specific rat cellular sequences that we find to be quite likely not those of a rat type c leukemia virus. to determine if these murine sarcoma viruses provide a model relevant to the events occurring in spontaneous tumors, we have hybr ...1976176419
genomic complexities of murine leukemia and sarcoma, reticuloendotheliosis, and visna viruses.the genetic complexities of several ribodeoxyviruses were measured by quantitative analysis of unique rnase t1-resistant oligonucleotides from 60-70s viral rnas. moloney murine leukemia virus was found to have an rna complexity of 3.5 x 10(6) daltons, whereas moloney murine sarcoma virus had a significantly smaller genome size of 2.3 x 10(6). reticuleondotheliosis and visna virus rnas had complexities of 3.9 x 10(6), respectively. analysis of rnase a-resistant oligonucleotides of rous sarcoma vi ...1976176429
an improved assay for feline leukaemia virus pseudotypes of murine sarcoma assay is described for feline leukaemia virus pseudotypes of murine sarcoma virus which increased the virus titre by about 100-fold over conventional assays. the titre is independent of dilution and no secondary focus formation occurs. the assay may be used to study virus neutralization and to detect and type feline leukaemia virus in feline embryo cells by interference.1976177726
genetics of murine sarcoma virus (msv)--induced tumors in akr mice: evidence that late progressing and early regressing tumors are controlled by different gents.the genetics of late appearing msv tumors showing a progressive growth pattern in akr mice was investigated. the late msv tumor response in f1 hybrids depended on the genetic background of the non-akr parent. within the 4-month observation period following virus injection, (cba x akr) f1, (dba/2 x akr)f1, and (nih x akr)f1 developed progressing msv tumors, which exhibited latency and growth behavior comparable to that seen in akr mice, (balb x akr)f1, (b6 x akr)f1, and (b10br x akr)f1 mice did n ...197766212
retransformation of a thermosensitive balb/c-3t3 transformant by murine sarcoma virus at the non-permissive temperature. 1976179009
revertants of human cells transformed by murine sarcoma virus.revertants of nonproducer human osteosarcoma (np/khos) cells induced by kirsten murine sarcoma virus were isolated after incubating at high temperature (40.5 degrees c) overnight and subcloning at 36 degrees c. the morphologic variants, from which murine sarcoma virus could no longer be rescued, had growth properties similar to those of the nontransformed, parent human osteosarcoma cells and did not release rna-dependent dna polymerase activity. these revertants were nontumorigenic in nude mice. ...197662397
characterization of effector lymphocytes associated with immunity to murine sarcoma virus (msv) induced tumors. i. physical properties of cytolytic t lymphocytes generated in vitro and of their immediate progenitors.cytolytic t lymphocytes (ctl) were generated in secondary mixed leukocyte-tumor cell cultures (mltc) with syngeneic rb1-5 tumor cells as stimulating cells and with responding spleen cells from regressor mice that had rejected a murine sarcoma virus (msv)-induced tumor. ctl precursor cells were found to be exclusively of thymic origin and non-t cells were apparently not required for ctl generation. when the size variations of ctl from syngeneic mltc were analyzed by velocity sedimentation it appe ...1976180182
inhibition of murine sarcoma virus induced transformation by adenovirus structural proteins.the purified fibre and hexon of adenovirus 12 inhibit the transformation in tissue culture of murine sarcoma virus (msv-m) by as much as 80% and 70%, respectively, when they are added to cells 8 to 2o h before msv-m infection. during a 12 h period, only about 6 to 8% of added radiolabelled viral proteins become associated with cells (or i-o mug protein bound/10(5) cells). no inhibition occurs when the proteins are added simultaneously with msv-m or 90 min or 4 h after msv-m. there is also a dire ...1976180250
phenotypic mixing between n- and b-tropic murine leukemia viruses: infectious particles with dual sensitivity to fv-1 effort to understand how n or b tropism is determined in murine leukemia virus (mulv) particles, we analyzed the mulv produced after dual infection of mouse cells by n- and b-tropic mulv. the progeny mulv from such a mixed infection are sensitive to fv-1 restriction in both n- and b-type cells, but are still highly infectious for mouse cells which do not exhibit fv-1 restriction. this dual sensitivity to fv-1 restriction is a phenotypic property of mulv produced by mixedly infected cells, sin ...1976181144
tumor inhibiting capacity of spleen and lymph node cells from mice with murine sarcoma virus (msv-m)-induced tumors.the direct tumor inhibiting capacity of spleen and lymph node cells obtained from mice in different stages of moloney sarcoma virus (msv-m)-induced tumor development was studied. msv-m producing ascitic tumor cells with a tumor dosis50 of about 10(3) cells and a mean latent period--depending on the amount of transplanted cells--of6-12 days were used as target cells. they were mixed with dilutions of spleen and lymph node cells obtained from mice at various times after infection with msv-m. the c ...1975181922
spontaneous release of endogenous ecotropic type c virus from rat embryo cultures.type c viruses were isolated from embryo cultures of two different rat strains, sprague-dawley and fischer. both viruses (termed rat leukemia virus, ralv) were released spontaneously from rat embryo cells, have a density of 1.14 to 1.15 g/cm(3) based on equilibrium sedimentation in sucrose gradients, contain 60-70s rna, rna-directed dna polymerase, and rat type c virus-specific 30,000 molecular-weight-protein determinants. molecular hybridization studies using the sprague-dawley ralv 60-70s rna ...197658077
glycolytic enzyme activities in murine sarcoma virus-transformed cultures of balb 3t3. the role of culture density. 1976183120
increased ornithine decarboxylase activity in murine sarcoma virus infected cells. 1976183140
genetic control of oncogenesis by murine sarcoma virus moloney pseudotype. iii. possible correlation with endogenous virus production. 1975183715
murine sarcoma virus defectiveness: serological detection of only helper virus reverse transcriptase in sarcoma virus rescued from nonmurine s + l-cells. 197657666
cell-mediated immunity to leukemia virus- and tumor-associated antigens in mice.cell-mediated immune reactions appear to play an important role in resistance against growth of leukemia cells in mice. possible mechanisms for in vivo protection in two tumor systems are discussed. these tumor models, which are a friend leukemia virus-induced transplantable tumor, fbl-3, and primary murine sarcoma virus (msv) -induced tumors, are strongly antigenic; under some conditions, tumors regress completely. in mice with regressing fbl-3 tumors, cell-mediated cytotoxicity was measured by ...197656223
nucleotide sequences in mouse dna and rna specific for moloney sarcoma virus.complementary dna (cdna) synthesized by moloney murine sarcoma virus (m-msv) was separated into two parts, the first, termed msv-specific cdna, composed of nucleotide sequences found only in m-msv viral rna, and the second, termed msv-mulv common cdna, composed of nucleotide sequences that were found in both m-msv and murine leukemia virus (mulv) viral rnas. rna complementary to the msv-specific cdna was not found in several other msv isolates, nor in ecotropic mulv, mouse mammary tumor virus, o ...1976185623
mouse msv transformed cells resistant to 8-azaguanine.mouse cells transformed by murine sarcoma virus were made resistant to 8-azaguanine. resistant cells and cell clones isolated from them were deficient in hypoxanthine-guanine phosphoribosyl transferase (hgprt) activity. they did not grow in hatg medium, did not incorporate labeled hypoxanthine, and had negligible hgprt activity. the resistance was genetically stable. the resistant cells were hyperdiploid and contained telocentric chromosomes only. the resistant cells as well as the progenitor ce ...197555981
thermolabile reverse transcriptase of a mammalian leukemia virus mutant temperature sensitive in its replication and sarcoma virus helper functions.three temperature-sensitive mutants of the rauscher strain of murine leukemia virus are defective in early post-penetration functions required both for leukemia virus infection and for initiation of transformation of cells by their pseudotypes of murine sarcoma virus. in the present study, the reverse transcriptase of one of these mutants (ts 29) is shown to be thermolabile compared with the enzymes of the wild-type virus and several other temperature-sensitive mutants. these findings provide ev ...197553294
secondary specific immune response in vitro to msv tumor cells.the interactions which occur between antigenic tumor cells and normal or immune lymphoid cells in a 3-day in vitro culture, have been studied with a murine sarcoma virus (msv)-induced tumor. the 3h-thymidine incorporation of lymphoma cells growing in suspension, and the radioactive-chromium release of freshly sampled lymphoma cells regularly added to the culture, have been compared to determine the part played by immune lymphoid cells in cytolysis and cytostasis of the tumor-cell population. the ...197553210
rapid screening assay for revertants of murine sarcoma virus-transformed cells. 1976187898
prevention of spontaneous leukemia in akr mice by type-specific immunosuppression of endogenous ecotropic virogenes.akr/j mice, 80-90% of which ordinarily die of spontaneous lymphocytic leukemias by 12 months of age, were significantly protected from developing leukemia in the initial experiment by a single course of treatment with akr serotype-specific antibodies mad in goats and processed as immune gamma globulin (igg). in experiment 1, igg was given on the day of birth and on four additional days, and finished on day 14. this schedule resulted in suppression of over 4 logarithms of normal virogene expressi ...1976188047
detection of human c-type "helper" viruses in human leukemic bone marrow with murine sarcoma virus-transformed human and rat non-producer cells.bone-marrow cells from two leukemic children were co-cultivated with the leukemic children a 7573. in early passages, c-type oncornaviruses were released as detected by extracellular reverse transcriptase assay. co-cultivation of the infected canine cells with the non-producing cell lines r-970-5 (human) or k-nrk (rat) both transformed by kirsten mouse sarcoma virus (msv) yielded a new pseudotype of msv that could transform rat embryo, rabbit sirc and human kidney cells but not mouse embryo cell ...1977188771
transformation of cultured rat adrenocortical cells by kirsten murine sarcoma virus (ki-msv).two-week-old primary cultures of normal adult rat adrenal cortex were exposed to kirsten murine sarcoma virus (kimsv). within a week, the adrenal cells, which are normally fusiform and aligned in parallel, became pleomorphic and piled up extensively. saturation density increased from 5-10 x 10(4) to 5-10 x 10(5) cells/cm2, population doubling time during exponential growth decreased from 36-40 to 16h, acid production increased and the growth rate became independent of a reduction in serum concen ...1977188772
murine sarcoma virus defectiveness. viral polymerase expression murine and nonmurine host cells transformed by s+l-type murine sarcoma virus. 197552940
characterization of murine sarcoma virus transformation of guinea pig cells and activation of an rna tumor-like virus from nonproducer guinea pig cells.guinea pig embryo (gep) cells were transformed in vitro by the kirsten strain of mouse sarcoma virus (ki-msv). the transformed cells were found to release infectious virus continuously and produced high titers of group-specific (gs) complement-fixing (cf) antigen characteristics of the murine sarcoma-leukemia virus complex. foci of transformed cells were similar in appearance to those obtained with ki-msv in mouse and rat cells. the transformed cells produced rna dependent dna polymerase and typ ...197551621
murine sarcoma viruses: the helper-independence reported for a moloney variant is unconfirmed; distinct strains differ in the size of their rnas. 1977189494
inhibition of purified dna polymerase of rna tumor viruses by fluoranthene derivatives and analogues of tilorone concentrations of 7 times 10(-6) to 7 times 10(-5) m, derivatives consisting of the polycylic ring structures fluoranthene, fluorenone, fluorene, anthraquinone, xanthenone, and dibenzofuran with appropriate amine side chains inhibited by over 90% the purified rna-directed dna polymerase of avian myeloblastosis virus acting on poly(deoxyadenylate-deoxythymidylate) [poly(da-dt)]. of these, only the fluoranthene derivatives were strong inhibitors of the viral dna polymerase directed by polyadeny ...197551087
differential genetic susceptibility of cultured human skin fibroblasts to transformation by kirsten murine sarcoma virus.hereditary adenomatosis of the colon and rectum (acr), an autosomal dominant trait, is associated with a predisposition to neoplasia. the present study describes the differential genetic susceptibility of cultured human skin fibroblasts to transformation by kirsten murine sarcoma virus. primary cutaneous outgrowths were derived from normal appearing subepidermal biopsies of acr phenotypes and appropriate controls. exponentially growing cell cultures from acr subjects and a portion of the clinica ...1977189938
expression of viral envelope glycoprotein and transformation genes in cells transformed by a defective kirsten murine sarcoma virus. 1977190782
loss of fv-1 restriction in balb/3t3 cells following infection with a single n tropic murine leukemia virus particle.the ability of various murine leukemia viruses (mulvs) to replicate in mouse cells exhibiting fv-1 restriction was analyzed by quantitative dose-response assays. in particular, the effect of infection with n, b, or nb tropic mulvs on fv-1b restriction in balb/3t3 cells was measured with an infection center technique in which pseudotypes of murine sarcoma virus (msv), which have been shown to exhibit fv-1 dependence of expression, were used to quantitate the degree of restriction. the resulting d ...1977191197
recent studies on the identification of proliferative abnormalities and of oncogenic potential of cutaneous cells in individuals at increased risk of colon cancer.this recent study describes the growth characteristics of acr skin fibroblasts in culture and their differential susceptibility to transformation by kirsten murine sarcoma virus (ki-msv). the sf were derived from normal appearing subepidermoid biopsies of acr individuals, their progeny and ocntrols. normal sf were contact-inhibited and grew only in 15% fcs. sf of acr subjects, and some asymptomatic acr progeny were not contact inhibited, grew in both 1% and 15% fcs and were considerably more sus ...197611561
the correlation of plasma membrane microvilli and intracellular cyclic amp content in a rat epitheloid kidney cell line.modulation of the intracellular concentration of cyclic amp has been associated with a regulatory role in cell division, cell morphology, and physical properties of the plasma membrane. untransformed rat kidney cells in culture exhibit epitheloid morphology, high intracellular cyclic amp levels, and contact inhibition of growth. untransformed rat kidney cells transformed with the kirsten murine sarcoma virus exhibit a low cyclic amp content, rapid growth rate, and a loss of contact inhibition. s ...1976191699
association of the glycolipid pattern with antigenic alterations in mouse fibroblasts transformed by murine sarcoma virus.the level of the neutral glycolipid, galnac beta 1 leads to 4 gal beta 1 leads to 4glc leads to cer (asialo gm2), in balb/c 3t3 mouse fibroblasts transformed by kirsten murine sarcoma virus (3t3kimsv) was greatly increased compared to the nontransformed parental cells (3t3). this elevated chemical quantity was found to be localized on the surface of intact cells and accessible to external reagents, as detected by immunofluorescence and labeling with galactose oxidase: nab3h4. furthermore, immuni ...1977192447
heat sensitivity of murine sarcoma virus.murine sarcoma virus (moloney) was found to be heat labile. inactivation curve represents a first-order kinetics at temperatures between 30 degrees and 60 degrees. inactivation constant analysis showed an inflexion at about 45 degrees, and the activation energy was calculated as 67.6 kcal/mol for higher temperature range and 7.95 kcal/mol for lower temperature range. nature of inactivation is also discussed.1975168117
relationships between h-2 and viral antigens in murine oncornavirus-induced tumours.cytolytic t lymphocytes (ctl) from murine sarcoma virus (msv) or friend leukaemia virus (flv) inoculated mice lyse syngeneic much more efficiently than allogeneic fmrgi+ lymphoma cells. by comparing the cytolysis of various h-2 different 51cr lymphomas by ctl from several inbred and congenic lines differing at h-2, and by competition experiments using unlabelled cells, one can demonstrate that this phenomenon is due to an h-2 barrier. h-2b/h-2d hybrid-anti-msv-ctl immunized by h-2b, h-2d or h-2b ...1977192802
genetic studies of the ploidy of moloney murine leukemia assay for moloney murine leukemia virus was developed that made use of the production of morphologically altered foci in nonproducer mouse cells (15f) carrying murine sarcoma virus. wild-type (wt) virus gave a ratio of titers at 39 degrees c/34degrees c = 1.05 +/- 0.45 (standard deviation;n = 20). a spontaneous, thermosensitive (ts) mutant of moloney murine leukemia virus, ts3, defective in a late viral function, gave 39 degrees c/34degrees c = 0. a murine cell line (tb) was mixedly infected ...1977192918
different mechanisms for morphologic reversion of a clonal population of murine sarcoma virus-transformed nonproducer cells. 1977193260
growth of murine sarcoma virus-transformed rat kidney cells in nude mice: absence of induction of host endogenous viruses.clonal isolates of the normal rat kidney cell line (nrk) transformed by a defective murine sarcoma virus (kirsten strain) were injected into nude mice of balb/c background to determine whether the growth of these cells as tumors was accompanied by the induction of host endogenous type c viruses. all the virus-transformed clones produced rapidly growing tumors in nude mice, but neither the induction of mouse endogenous viruses nor the rescue and spread of the transforming sarcoma virus were obser ...1977194043
evaluation of the cell-mediated immune response to murine sarcoma virus by (125i)iododeoxyuridine assay and comparison with chromium 51 and microcytotoxicity assays.the cell-mediated immune response of c57bl/6 mice to murine sarcoma virus (msv) was examined by the [125i]-iododeoxyuridine release cytotoxicity assay using msv-induced sarcoma tissue culture cell lines as target cells. cellular cytotoxicity was detected as early as 3 days after virus inoculation. most mice assayed between 12 and 17 days after msv inoculation gave positive results with maximum levels of activity present on days 13 and 14. reactivity was frequently detected for up to 100 days aft ...1975167966
inherited resistance to n- and b-tropic murine leukemia viruses in vitro. effect of the fv-1 locus on the rescue of a replication-defective and transformation-defective murine sarcoma virus in the fv-1 congenic strains sim.s and sim.r. 1977194408
in vitro translation of harvey murine sarcoma virus rna.the viral rna of the harvey strain of murine sarcoma virus (ha-sv), which does not encode for any known viral structural polypeptides, has been translated in a nuclease-digested, cell-free system. the major protein product of the in vitro translation reaction has a molecular weight of 21,000 and is initiated faithfully with [35s]formylmethionine from formyl-[35s]methionyl-trnafmet. this polypeptide is clearly distinct from the rna of the moloney strain of type c helper virus used to pseudotype t ...1977195086
propagation of a b-tropic murine leukemia virus in n-type cells in the presence of different murine sarcoma viruses.b-tropic mulv, wn1802b, was converted to nb-tropic after 5 days of propagation in its nonpermissive n-type mlg or c3h2k cells in the presence of the s + l - musv, but not in the presence of the harvey or kirsten strains of mssv.1977195914
sarcoma-negative leukemia-positive transformed cell culture established from a murine sarcoma virus-induced rat bone tumor.inoculation of the soehner-dmochowski isolate of the moloney strain of murine sarcoma virus (msv), designated msv-sd, consistently leads to the development of bone tumors in the susceptible new zealand black (nb) rats. two separate cell cultures have been established from 2 individual msv-sd-induced nb rat bone tumors. cells of 1 bone tumor culture, designated rbt-e, are in early in vitro passages. these cells form colonies in agar medium and take up 2-deoxy-d-[3h]glucose at a greatly enhanced r ...1975167960
exclusive involvement of h-2db or h-2kd product in the interaction between t-killer lymphocytes and syngeneic h-2b or h-2d viral was demonstrated previously that the cytolysis of murine viral lymphoma cells by anti-murine sarcoma virus (msv) syngeneic t-killer lymphocytes was restricted by some products of the h-2 complex. the respective role of the products of different regions of the h-2 complex were studied with six h-2(b) and three h-2(d) lymphomas induced by five different type c viruses. they were tested in a classical chromium release test against anti-msv t-killer cells obtained from different inbred strains of ...1977197198
isolation and preliminary characterization of temperature-sensitive mutants of the murine sarcoma leukaemia virus complex.five temperature-sensitive mutants (ts i to 5) were isolated from a stock of the moloney strain of murine sarcoma leukaemia virus complex which had been mutagenized by ultraviolet irradiation or n-methyl-n'-nitro-n-nitrosoguanidine. in mouse cells at the non-permissive temperature the mutants formed fewer foci of transformed cells than at the permissive temperature. the ts mutants were characterized by testing: (i) murine leukaemia virus (mulv) clones from the ts complex, (2) the effect of addit ...1977197202
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