| 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 ... | 1976 | 11561 |
| purification and characterization of the dna polymerase and rnase h activities in moloney murine sarcoma-leukemia virus. | two rnase h (rna-dna hybrid ribonucleotidohydrolase, ec 3.1.4.34) activities separable by sephadex g-100 gel filtration were identified in lysates of moloney murine sarcoma-leukemia virus (msv). the larger enzyme, which we have called rnase h-i, represented about 10% of the rnase h activity in the virion. rnase h-i (i) copurified with rna-directed dna polymerase from the virus, (ii) had a sedimentation coefficient of 4.4s (corresponds to an apparent mol wt of 70,000), (iii) required mn-2+ (2 mm ... | 1975 | 46924 |
| cell-mediated immunity to moloney sarcoma virus in mice. i. analysis of antigens responsible for lymphocyte stimulation in regressor mice. | purified viruses, viral antigens, and cell extracts have been tested for their ability to stimulate protein synthesis by msv-m-1 regressor spleen cells from balb/c mice. immune, but not normal cells, responded to msv-m, but not to msv-g virus-1, and to the type-specific viral envelope glycoprotein from msv-m virus. extracts of mouse embryo fibroblasts transformed by either msv-m or msv-g, however, specifically stimulated msv-m regressor spleen cells. cells stimulated by different antigens, and b ... | 1975 | 47841 |
| a p60 polypeptide in the feline leukemia virus pseudotype of moloney sarcoma virus with murine leukemia virus p30 antigenic determinants. | a 60,000-dalton polypeptide (p60) has been identified in the feline leukemia virus (felv) pseudotype of moloney sarcoma virus [msv(felv)]. this polypeptide is present in the purified virus complex in concentrations greater than either the murine p30 or the feline p27. purified p60 crossreacts immunologically with murine p30 group antiserum and contains several interspecies determinants, whereas the group specific determinant of felv p27 is not detected. comparison of peptide fingerprints of p60 ... | 1975 | 49060 |
| antigenicity of carcinogen and viral induced sarcomas in inbred and random bred guinea pigs. | a tumor specific transplantation antigen (tsta) has been detected in a methylcholanthrene (mca) induced guinea pig tumor. it was possible to induce resistance to rechallenge with the tumor by immunization with irradiated cells in cfa. in contrast, the same technique failed to detect tsta in two viral (kirsten strain mouse sarcoma virus, ki-msv) induced guinea pig tumors; these results are similar to observations made with mouse ki-msv-induced tumors. transplantation studies with these tumors in ... | 1975 | 50348 |
| 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 ... | 1975 | 50851 |
| properties of oncornavirus rna-directed dna polymerase, the rna template, and the intracellular products formed early during infection and cell transformation. | we have investigated three aspects of rna turmor virus replication and cell transformation: (1) the properties of the purified avian and mammalian viral rna-directed dna polumerase, (2) some characteristics of the viral 60-70s rna genome, 30-40s rna subunits and intracellular viral rna species, and (3) the interaction of the viral dna polymerase with its rna template early during infection and cell transformation by the murine sarcoma-leukemia virus (msv[mlv]). avian myeloblastosis virus (amv) c ... | 1975 | 50902 |
| 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 ... | 1975 | 51621 |
| biochemical approach to bovine leukemia. | many bovine leukemic lymphocytes produce virus particles when kept in survival cultures in eagle's minimum essential medium supplemented with 20 percent of inactivated fetal calf serum. virus particles equilibrate at a density of 1.16 g/ml in sucrose gradients and at a density of 1.12 g/ml in metrizamide gradients. simultaneous detection tests show that a high molecular weight rna-reverse transcriptase complex exists in these viruses. hybridizations between total rna from bovine leukemic lymphoc ... | 1975 | 52980 |
| 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 ... | 1975 | 53210 |
| 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 ... | 1975 | 55981 |
| 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 ... | 1976 | 56223 |
| induction of a novel transforming virus (msv-z) from sarcoma-positive leukemia-negative 3t3fl mouse cells. | | 1976 | 56806 |
| 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 ... | 1976 | 59817 |
| 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 ... | 1976 | 61878 |
| cells transformed by certain strains of moloney sarcoma virus contain murine p60. | it was previously demonstrated that the 60,000 dalton (p60) precursor-like polyprotein containing murine p30 was a constituent of the feline leukemia virus pseudotype of moloney sarcoma virus [m1msv(felv)]. it is now shown that p60 is detected in cells of five mammalian species transformed by m1msv, indicating that p60 is specified by this genome. moreover, little or no murine p30 is detected in the m1msv-transformed cells, suggesting that the murine group p30 antigenic reactivity of s + l- cel ... | 1977 | 65230 |
| 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 ... | 1977 | 66212 |
| 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 ... | 1977 | 68817 |
| 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 ... | 1977 | 69721 |
| deposition of retrovirus associated antigens (p30 and gp70) on cell membranes of feline and murine leukaemia virus infected cells. | a quantitative estimation of retrovirus associated cell membrane antigens of murine and feline cells infected with their respective type c leukosis virus is presented. using a radio-immune assay with three broadly reactive antisera, the minimum estimated number of retrovirus associated antigenic determinants on yac [moloney leukaemia virus (mulv) infected murine] and fl-74 [feline leukaemia virus (felv) infected feline] cells was 1.3 x 10(6) and 1.6 x10(6) determinants per cell respectively. the ... | 1978 | 75945 |
| multiple rnase h activities in mammalian type c retravirus lysates. | lysates of moloney murine sarcoma-leukemia virus [m-msv(mlv)], a virus complex grown in the rat cell line 78a-1, were found to contain three rnase h species separable by polycytidylic acid[poly(c)]-agarose chromatography. rnase h activity (rnase h i) associated with rna-directed dna polymerase eluted at 0.23 m kci from poly(c)-agarose. rnase h ii, which eluted from poly(c)-agarose at 0.12 m kci and was not associated with dna polymerase activity, was shown to be identical to an rnase h species ( ... | 1978 | 77333 |
| 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 ... | 1978 | 80447 |
| origin and biological properties of a new balb/c mouse sarcoma virus. | a focus-forming virus previously isolated from a balb/c mouse hemangiosarcoma has been shown to be replication defective. analysis of individual balb/c mouse sarcoma virus (balb-msv) nonproducer transformants for expression of helper virus-coded proteins revealed genetically stable variants that expressed two, three, or all four gag gene products in the absence of detectable helper viral env gene expression. the type-specific antigenic determinants of helper viral proteins encoded by the balb-ms ... | 1978 | 80461 |
| 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 ... | 1977 | 81643 |
| 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 ... | 1979 | 84715 |
| antiserum to murine leukemia virus recognizes novel cell surface molecules associated with growth control and transformation. | antiserum directed against murine leukemia virus also reacts with several external proteins present in rat cells transformed by a temperature-sensitive rous sarcoma virus. reaction of iodinated cell extracts with anti-mlv (murine leukemia virus) serum revealed the presence of a 200,000 dalton iodinated component detectable also by metabolic labelling with glucosamine only in serum-starved cultures restricted in the expression of transformation. a similar assay with iodinated cells that express t ... | 1979 | 86526 |
| cell-mediated reactivity to antigens shared by moloney-virus-induced lymphomas (lstra) and certain 3-methylcholanthrene-induced mouse sarcomas. | spleen cells (sc) both from balb/c mice whose primary moloney sarcoma virus (msv)-induced sarcomas had spontaneously regressed and from normal, untreated balb/c mice, were co-cultivated for 5 days with mitomycin-c-treated lstra cells; lstra is a balb/c moloney lymphoma which shares cell surface antigens with msv-indiced sarcomas. these sc, referred to as cmr and cu cells, respectively, were shown to be cytotoxic to lstra cells in 3 h 51cr-release assays; cmr cells showed, in most cases, the grea ... | 1979 | 86527 |
| use of trypsin for rapid and efficient purification of murine sarcoma and leukemia virus. | a method is described for purification of msv-mulv from culture supernatant of chronically infected 78a,1 rat embryo cell line. this method involves direct polyethylene glycol-nacl precipitation of the low speed supernatant of culture fluid followed by digestion of the pellet with trypsin. this procedure efficiently disrupts large aggregates which normally entrap most of the virus. highly purified virus can be obtained in very good yield by a combination of sedimentation velocity and isopycnic c ... | 1978 | 88963 |
| 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 ... | 1975 | 122986 |
| 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 ... | 1975 | 128993 |
| [functional activity of cytolytic t lymphocytes in the rejection of tumor target cells]. | sensitized t lymphocytes can specifically destroy in vivo target cells with which they enter into direct contact. this suggests an important role for cytolytic t lymphocytes (ctl) in the destruction of grafts and tumours. quantitative methods allow the assay of ctl and of ctl memory cells which appear in lymphoid tissues, blood, grafts and tumours during rejection. the formation of ctl and ctl memory cells can also be induced in vitro, and the functional activity of such cells has been demonstra ... | 1977 | 139840 |
| 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 ... | 1979 | 156765 |
| moloney sarcoma virus-induced tumors in athymic (nude) mice: growth pattern and antibody responses. | tumor growth and antibody production were evaluated in nude (nu/nu) mice and their heterozygous normal (+/nu) littermates after inoculation of moloney sarcoma virus (msv). sarcoma-bearing nude mice developed progressively growing tumors, whereas 53 percent of their normal counterparts showed tumor regressions. by indirect membrane fluorescence, significant amounts of igg antibody to msv could be detected in thymus-bearing but not in nude mice. | 1975 | 164570 |
| transformation of horse skin cells by type-c sarcoma viruses. | a horse skin cell line (e. derm, nbl-6, ccl-57) was susceptible to focus formation by the kirsten mouse sarcoma virus, feline sarcoma virus (st stain) and the msv pseudotypes with woolly monkey, gibbon monkey, rd-114, at-124, baboon placenta and murine xenotropic (balb/c 3t3 and c57l/jd) type-c viruses. foci were detected within 5 days after infection and the transformed cells continued to produce infectious virus and group-specific antigen of their respective type-c leukemia viruses. the transf ... | 1975 | 165152 |
| 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 ... | 1975 | 167960 |
| 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 ... | 1975 | 167966 |
| 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 ... | 1975 | 168259 |
| 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 ... | 1975 | 169808 |
| 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 ... | 1975 | 169818 |
| 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 ... | 1975 | 169824 |
| 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 ... | 1975 | 169829 |
| 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 ... | 1975 | 170219 |
| 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 ... | 1975 | 170220 |
| derivation of mouse sarcoma virus (kirsten) by acquisition of genes from heterologous host. | the technique of virus rna-cellular dna hybridization in solution with dna excess was used to compared the nucleotide sequences of the 70 s rna genome of the kirsten mouse sarcoma virus (ki-msv) with that of mouse erythroblastosis virus (mev) which gave rise to ki-msv after in vivo propagation in rat. it is suggested that a loss of about 30% of the genomic sequences of mev with a concomitant gain of roughly equal amounts of rat-specific sequences in a genetically stable recombinant state led to ... | 1975 | 170369 |
| 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 ... | 1975 | 170419 |
| 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 ... | 1975 | 171336 |
| 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 ... | 1975 | 173498 |
| a comparison of membrane glycoconjugates from mouse cells transformed by murine and primate rna sarcoma viruses. | kirsten murine sarcoma virus (ki-msv) transformed balb/et3 mouse cells (k-balb) were found to have altered membrane glycoconjugates compared to normal balb/3t3 cells. there were reduced amounts of mono- and disialogangliosides, gm1 and gd1a, and activity of the specific galactosyltransferase required for synthesis of these gangliosides was reduced to between 0 and 18.5% of normal in the several k-balb clones examined. when fucose-labeled glycopeptides derived from the surfaces of balb/3t3 and k- ... | 1976 | 174712 |
| altered microfilament structure in cells transformed with a temperature-sensitive transformation mutant of murine sarcoma virus. | the structure and distribution of microfilaments were examined by electron microscopy in uninfected normal rat kidney (nrk) cells, murine sarcoma virus (msv)-transformed nrk cells, and nrk cells infected with a cold-sensitive transformation mutant of msv, i.e., nrk (msv-1b) cells, grown at both permissive (39 degrees) and nonpermissive (33 degrees) temperature. the uninfected cells contained numerous microfilaments which were especially prominent at sites of intercellular adherens junctions. in ... | 1976 | 174810 |
| attempts to induce tubular deformations and subsequent mixed tumours from organotypic cultures of mouse renal mesenchyma. | with the aim of expanding knowledge on the pathogenesis of nephroblastomata, an embryological organ culture system (grobstein, 1956) was tested for its applicability to in vitro carcinogenesis experiments by using murine sarcoma virus (msv-m) and 3-methylcholanthrene (mca). treatment of cba/h-t6 mouse metanephrogenic mesenchyma with msv-m at the pretubular stage neither disturbed the glomerulogenesis nor induced rapid malignant transformation. treatment of the same tissues with mca considerably ... | 1976 | 175592 |
| fractionation of dna nucleotide transcripts from moloney sarcoma virus and isolation of sarcoma virus-specific complementary dna. | radioactive dna complementary to nucleotide sequences in moloney murine sarcoma virus (msv) and moloney leukemia virus (m-mulv) complex was made by the endogenous reverse transcriptase reaction. these virus stocks contained a threefold excess of msv over m-mulv as measured by biological assay. the complementary dna was an accurate copy of the viral rna in that 86% of 35s viral rna hybridized with complementary (cdna) dna at a 1.5 to 1 cdna-rna molar ratio. the complementary dna, of a 4-6s size, ... | 1976 | 178890 |
| suppression of mixed lymphocyte response in mice bearing primary tumors induced by murine sarcoma virus. | mixed lymphocyte culture (mlc) responses of spleen cells from mice bearing tumors induced by murine sarcoma virus of the moloney type (msv) against allogeneic spleen cells were found to be markedly depressed, as estimated by three parameters: lymphoblast counts, 3h-thymidine incorporation (ti), and cell-mediated lysis (cml). while all three parameters were definitely depressed in comparison to the normal controls, ti was depressed to a greater degree than lymphoblast counts and cml. msv spleen c ... | 1976 | 179171 |
| 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 ... | 1976 | 180182 |
| 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 ... | 1976 | 180250 |
| phenotypic mixing between n- and b-tropic murine leukemia viruses: infectious particles with dual sensitivity to fv-1 restriction. | in 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 ... | 1976 | 181144 |
| 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 ... | 1975 | 181922 |
| the 30s moloney sarcoma virus rna contains leukemia virus nucleotide sequences. | the 50s-70s rna of a moloney sarcoma-leukemia virus [mo-msv(mlv)] complex produced by a particular mouse cell line was shown by gel electrophoresis to contain a major (97%) 30s sarcoma-specific subunit species and a minor (3%) 38s leukemia virus-specific subunit. on the basis of its sedimentation coefficient and known complexity, the 30s mo-msv rna was estimated to be a unique rna molecule of about 6000 nucleotides. hybridization experiments using viral rna and dna complementary to viral rna (cd ... | 1976 | 184965 |
| primary and secondary in vitro generation of cytolytic t lymphocytes in the murine sarcoma virus system. | cell-mediated cytotoxic responses in vitro to surface antigens associated with murine sarcoma virus (msv)-induced tumors were investigated using mixed leukocyte-tumor cell cultures (mltc). the source of responding cells was either spleens from normal c57bl/6 mice (primary mltc) or spleens of c57bl/6 mice carrying or having rejected a msv-induced tumor (secondary mltc). graffi virus-induced gil-4 leukemia cells, rauscher virus-induced rb1-5 leukemia cells, and msv-induced msv-b16 sarcoma cells we ... | 1975 | 185057 |
| 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 ... | 1976 | 185623 |
| role of interferon in the pathogenesis of virus diseases in mice as demonstrated by the use of anti-interferon serum. ii. studies with herpes simplex, moloney sarcoma, vesicular stomatitis, newcastle disease, and influenza viruses. | the effect of potent sheep anti-mouse interferon globulin was investigated in several different experimental virus diseases of mice. in anti-interferon globulin-treated mice infected intraperitoneally with herpes simplex virus (hsv) type i, the latent period was shortened, and the overall ld50 was increased several hundredfold compared to virus-infected control mice. when hsv was inoculated subcutaneously all anti-interferon globulin-treated mice died, whereas only 5% of virus-infected control m ... | 1976 | 186555 |
| antigenic specificity of the cytolytic t lymphocyte (ctl) response to murine sarcoma virus-induced tumors. i. preferential reactivity of in vitro generated secondary ctl with syngeneic tumor cells. | incubation of spleen cells from mice having rejected a moloney sarcoma virus (msv)-induced tumor with syngeneic irradiated lymphoma or sarcoma cells bearing msv-associated antigens in secondary mixed leukocyte-tumor cell cultures (mltc) resulted in the generation of highly active cytolytic t lymphocytes (ctl) specifically directed against syngeneic target cells bearing msv-associated antigens. when msv-immune spleen cells from c57bl/6 (h-2b) and balb/c(h-2d) mice were compared with respect to th ... | 1976 | 187429 |
| 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 ... | 1977 | 188771 |
| 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 ... | 1977 | 188772 |
| rate of divergence of cellular sequences homologous to segments of moloney sarcoma virus. | the rna genome of the moloney isolate of murine sarcoma virus (m-msv) consists of two parts--a sarcoma-specific region with no homology to known leukemia viral rnas, and a shared region present also in moloney murine leukemia virus rna. complementary dna was isolated which was specific for each part of the m-msv genome. the dna of a number of mammalian species was examined for the presence of nucleotide sequences homologous with the two m-msv regions. both sets of viral sequences had homologous ... | 1977 | 189062 |
| morphological, biological, immunological and biochemical studies on bone tumors of animals and man. | biological studies on fbj osteosarcoma virus in tissue cultures have led to the isolation of murine sarcoma virus. characteristic type c-mulv particles were observed in bone tumors induced by the sd-msv-m-virus in vitro and in vivo. the sd-msv-m virus also induced bone tumors in rats of all strains tested, and it has a similar tumor-inducing property in hamsters. immunoelectronmicroscopic studies showed that envelope antigens of msv-sd virus in rat bone tumors can be distinguished from those fou ... | 1976 | 189370 |
| virus-induced animal model of osteosarcoma in the rat: morphologic and biochemical studies. | osteosarcomas were produced by the intratibial inoculation of new zealand black rats with moloney sarcoma virus (msv) at 1 day and 4 days of age. radiographic evidence of osteosarcoma development was first demonstrated at 10 to 15 days postinoculation in both groups. subsequent radiographic and light and electron microscopic evaluation of tumor-bearing rats demonstrated that osteosarcomas in rats inoculated at day 4 of age were more osteoproliferative osteosarcomas than those in rats inoculated ... | 1977 | 189616 |
| effect of pretreatment with immune serum on murine sarcoma virus (moloney) tumour induction and growth. | regressor serum from msv-m-infected mice markedly reduced msv-m oncogenesis when administered i.p. (0-1 ml/mouse) as much as 30 days before i.m. msv-m infection in adult balb/c mice. the regressor serum activity appeared to be directly dependent on the amount of igg, as shown by: (1) inactivity of sera which have low virus-neutralizing antibody content; (2) high effectiveness only of the igg serum fraction; (3) inactivity of regressor serum incubated with anti-mouse gamma-globulin serum. the reg ... | 1977 | 189792 |
| 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 ... | 1977 | 191197 |
| stimulation of mouse migration inhibitory factor (mif) production form msv-immune lymphocytes by soluble tumor-associated antigen: requirement for histocompatible macrophages. | spleen cells from c57bl/6 mice immunized with murine sarcoma virus (msv) are capable of producing migration inhibition factor (mif) in response to stimulation with a specific tumor-associated antigen prepared by solubilization with 3 m kcl. we have previously demonstrated that this response is t cell-dependent. further investigations into the effector cells involved in the production of mif have revealed that spleen cells from mice immunized with msv cannot produce mif when stimulated with tumor ... | 1977 | 191532 |
| murine sarcoma virus pseudotypes used as immunogens against viral and chemical oncogenesis. | the purpose of this study was to develop an animal system of protective immunity against oncornaviruses and to test whether such immunization had an inhibitory effect upon chemical sarcomagenesis. several murine sarcoma virus (msv) pseudotypes were used as immunogens and tested against themselves, against other pseudotypes, against leukemogenesis by their helper viruses, and against sarcomagenesis by 3-methylcholanthrene. five msv pseudotypes were obtained by rescuing complete msv from msv-genom ... | 1977 | 192461 |
| 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 ... | 1977 | 192802 |
| characterization to effector lymphocytes associated with immunity to murine sarcoma virus (msv)-induced tumors. ii. repeated stimulation and proliferation in vitro of specific cytolytic t lymphocytes. | | 1977 | 196025 |
| exclusive involvement of h-2db or h-2kd product in the interaction between t-killer lymphocytes and syngeneic h-2b or h-2d viral lymphomas. | it 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 ... | 1977 | 197198 |
| effect of helper virus on the number of murine sarcoma virus dna copies in infected mammalian cells. | cell lines of four mammalian species were each examined for the number of moloney murine sarcoma virus (m-msv) dna copies in total cellular dna after m-msv transformation. sarcoma-positive, leukemia-negative (s+l-) m-msv-transformed cells were compared to m-msv-transformed cells infected with a replicating leukemia virus. both unfractionated m-msv complementary dna and complementary dna representing the msv-specific and the msv-murine leukemia virus-common regions of the m-msv genome were hybrid ... | 1977 | 197257 |
| relationship between moloney murine leukemia and sarcoma virus rnas: purification and hybridization map of complementary dnas from defined regions of moloney murine sarcoma virus 124. | complementary dnas (cdna's) specific for various regions of the moloney murine sarcoma virus (msv) 124 rna genome were prepared by cross-hybridization techniques. a cdna specific for the first 1,000 nucleotides adjacent to the rna 3' end (cdna 3') was prepared and shown to also be complementary to the 3'-terminal 1,000 nucleotides of a related moloney murine leukemia virus (mlv) genome. a cdna complementary to the "msv-specific" portion of the msv 124 genome was prepared. this cdna was shown not ... | 1977 | 197259 |
| cyclic amp-induced morphological transformation of cells infected by temperature-sensitive mouse sarcoma virus. expression of transformation-associated markers. | normal rat kidney (nrk) cells infected with a temperature-sensitive (ts) mutant of mouse sarcoma virus (nrk [msv-1b]) express the transformed phenotype when grown under permissive conditions, but acquire the normal phenotype when grown under restrictive conditions. addition of 3', 5' cyclic adenosine monophosphate (camp) to nrk (msv-1b) cells grown at the restrictive temperature results in morphological transformation. to determine whether other markers associated with the transformed phenotype ... | 1977 | 198411 |
| characterization of gazdar murine sarcoma virus by nucleic acid hybridization and analysis of viral expression in cells. | gazdar murine sarcoma virus (gz-msv) and moloney murine sarcoma virus (m-msv) are closely related. the complete m-msv-specific nucleic acid sequences constituted a major portion of gz-msv-specific sequences. the msv-specific sequences in both gz-msv and m-msv genomes shared homology with hamster leukemia virus nucleic acid sequences. both rat cells (s+l+) and hamster (s+l-) cells expressed two viral proteins of 68,000 and 70,000 daltons. these proteins were immunologically related to p60 purifie ... | 1977 | 199741 |
| relationship between moloney msv tumor resistance and endogenous virogene expression in akr mouse strain and its hybrids. | we have examined the induction of moloney-msv tumors in akr and other mouse strains in relation to endogenous virus expression. all virus-free strains so far tested were tumor-susceptible, while akr was resistant. the selectivity of msv tumor resistance, characteristic of akr mice, was associated with akr virogens segregation in first backcross to mulv-negative/msv-susceptible mice, and in a few second backcross families. stronger evidence that akr ecotropic virogene expression is the major, but ... | 1978 | 203548 |
| studies with the baboon endogenous virus and its pseudotype of murine sarcoma virus in marmosets. | three marmoset species (saguinus oedipus oedipus, s. fuscicollis, callithrix jacchus) failed to show evidence of infection or disease following inoculation of baboon endogenous type-c virus (baev). cells infected with a kirsten murine sarcoma-baev pseudotype (msv[baev]) produced a progressive fibrosarcoma in s. o. oedipus and tumors in s. fuscicollis and c. jacchus which regressed. tumor formation is believed to be due to growth of inoculated, virus-infected cells and not transformation of marmo ... | 1978 | 205851 |
| replication of mouse sarcoma virus (moloney) and its helper in a human heteroploid cell line of malignant origin. | a human heteroploid cell line of malignant origin (j111) was infected with mouse moloney sarcoma virus. [msv-m(mlv)]. the replication of the virus was demonstrated by different methods. after a few passages of infected cultures, the transforming component of msv-m(mlv) disappeared from the supernatant fluids and cells. the non transforming helper component continued to be produced. the relatively low amount of helper virus released by the cells suggests a control of its replication in the j111 c ... | 1977 | 206868 |
| transformation of indian muntjac cells by murine and avian sarcoma viruses. | indian muntjac cells were efficiently transformed by murine sarcoma virus (msv) and avian sarcoma viruses (asv). when colony formation of the infected cells was examined in soft agar, many colonies were formed by the asv-injected cells but no colony was seen in the msv-infected cells. the asv-transformed cell clones differed among the clones in morphology, presence of inducible asv genome, and karyotypes. | 1978 | 208907 |
| effect of interferon on murine leukemia virus infection. iii. effect of interferon on msv-induced transformation. | | 1978 | 213891 |
| [effect of sodium butyrate on the interferon sensitivity of normal or cells transformed by murine sarcoma virus]. | sodium butyrate enhances the sensitivity of msv transformed murine cells to interferon, but does not influence the response of normal cells. sodium butyrate might act in transformed cells by restoring the different elements of the cytoskeletal system. | 1978 | 214252 |
| significance of the proline assay in the study of anti-msv cell-mediated immune reactions. | the cytolysis of 3h-proline-labelled tumour cells growing in monolayer by syngeneic immune lymphocytes has been studied in the murine sarcoma virus (msv) system. results show that the proline assay (pa) is a convenient way to reveal the activity of cytolytic t lymphocytes against fmr-like antigens. using the same effector and target cells, the classical chromium-release test (crt) fails to reveal any cytolytic activity, and the visual microcytotoxicity assay as well as several derived isotopic m ... | 1979 | 215185 |
| prevention of spontaneous leukemia in mice by oncornavirus immunization. | c57l, nih, and swr mice were immunized with inactivated gross leukemia virus (glv) and then mated with akr males. their f1 offspring were then immunized with the murine sarcoma virus pseudotype of glv, msv(glv). the concentrations of infectious ecotropic akr virus in tail extracts of immunized mice were 100- to 1,000-fold lower than in non-immunized controls when tested at 30--40 days of age. although viral titers increased slightly with time, the titers remained at least one log10 lower in the ... | 1979 | 216644 |
| chemical determination of the m1 moloney sarcoma virus pp60gag gene order: evidence for unique peptides in the carboxy terminus of the polyprotein. | the gene order of the ml moloney sarcoma virus (mlmsv) specific pp60gag (p60) was determined by direct chemical analysis of the polyprotein. p60 was cleaved with cyanogen bromide (cnbr) into eight partial and complete fragments ranging in mass from 10,000 daltons to 58,000 daltons. peptide maps of these fragments were compared to maps of p15, p12, and three cnbr fragments of p30. the polarity of p15 and p12 in a cnbr fragment of p60 was determined by carboxypeptidase a digestion; likewise the cn ... | 1978 | 216995 |
| revertants of mouse cells transformed by murine sarcoma virus. v. loss of msv-specific nucleotide sequences from cellular rna. | | 1978 | 217157 |
| application of antisera to interferon in studying oncogenic viruses. | susceptibility of balb/c mice to infection with moloney sarcoma virus (msv) and to herpes simplex virus type 2 (hsv-2) was considerably increased by administration of sheep anti-mouse interferon (anti-if) serum. the regression of the msv-induced tumors was inhibited when the weanling (three-to-four-week-old) mice were injected with the anti-if serum. using the anti-if serum it has been found that the antagonism between hsv-2 and rauscher leukemia virus in the mouse is not mediated by interferon. ... | 1978 | 219809 |
| cell-mediated immunity to antigens associated with murine sarcoma virus-induced tumors: augmentation of cytolytic t lymphocyte activity by successive specific and nonspecific stimulation in vitro. | it has been shown previously that lymphoid cells from mice which have rejected a tumor induced by the moloney sarcoma virus-leukemia virus (msv-mlv) complex develop high levels of specific h-2-restricted cytolytic t lymphocyte (ctl) activity after in vitro stimulation with syngeneic, irradiated mlv-induced lymphoma cells in mixed leukocyte-tumor cell cultures (mltc). attempts to further increase lytic activity by restimulating long-term mltc cells with syngeneic, irradiated lymphoma cells have m ... | 1979 | 221224 |
| genome organization of retroviruses. iii. restriction endonuclease cleavage maps of mouse sarcoma virus double-stranded dna synthesized in vitro. | genome length complementary dna (cdna) transcripts were synthesized in vitro by using purified virions of a cloned isolate of mouse sarcoma virus (msv clone 124). the cdna transcripts were converted to double-stranded form by utilizing dnase-digested calf thymus dna primers and e. coli dna polymerase i. restriction endonucleases sal i, hind iii, hpa i, bgl ii and xba i were found to cleave the msv double-stranded dna once to generate two fragments, whereas restriction endonucleases bgl i and hae ... | 1979 | 221890 |
| cycloheximide-dependent reversion of human cells transformed by msv and chemical carcinogen. | the protein synthesis inhibitor cycloheximide, at a concentration of 0.08 microgram per milliliter, induced flat morphology within 24 to 48 hours and low saturation density in human osteosarcoma cells transformed by kirsten murine sarcoma virus (ki-msv) or n-methyl-n' nitro-n-nitrosoguanidine. removal of the protein synthesis inhibitor caused both transformed cells to revert to the transformed phenotype. the demonstration of cell-surface antigens, cross-reacted with antiserums induced by extract ... | 1979 | 223242 |
| [transplantable experimental tumor. morphological and ultrastructural study (author's transl]. | an experimental tumor which has been induced in newborn chicken, was transplanted into inbred balb/c mice and then studied by the means of light and electron microscopy. sendai virus fusion between msv-h transformed rat cells and chickembryo cells provided the tumor. histological pattern of this neoplasia seems to be superposable, both in chicken and in mouse, to that of anaplastic fibrosarcomas and shows some differences from either rous sarcoma or balb/c mouse h-6668 spontaneous rabdomyosarcom ... | 1978 | 224888 |
| an interferon-sensitive early step in the establishment of infection of murine cells by murine sarcoma/leukaemia virus. | nih 3t3 mouse cells were infected at very high multiplicity with murine sarcoma/leukaemia virus (msv/mlv) and then cloned. all of the 48 clones obtained were morphologically transformed, all but one showed anchorage-independence of growth, typical of msv-transformed nih 3t3 cells and most (91%) produced msv/mlv. when cells which had been pre-treated with 10(4) units/ml of purified interferon (if) were infected under the same conditions and then cloned in the presence of the same amount of if, on ... | 1979 | 225416 |
| reversion of kirsten sarcoma virus transformed human cells: elimination of the sarcoma virus nucleotide sequences. | the virus-specific nucleotide sequences in the rna and dna of a kirsten mouse sarcoma virus (ki-msv)-transformed non-producer human osteosarcoma cell clone and two subclones of these cells that reverted to a normal phenotype have been analysed by hybridization of sarcoma virus-specific complementary dna (cdna) to cellular rna or dna. whereas the transformed clone had acquired de novo ki-msv sequences in the rna and dna of the cells, both the revertant cell lines seemed to have lost most or all o ... | 1979 | 225428 |
| p21 of kirsten murine sarcoma virus is thermolabile in a viral mutant temperature sensitive for the maintenance of transformation. | we have recently described an intracellular protein, p21, in nonproducer cells transformed by either the kirsten (ki-msv) or harvey (ha-msv) strain of murine sarcoma virus (shih et al., virology, in press). the p21 is phosphorylated and has been shown to be coded for by either ki-msv or ha-msv. in this report, we compare the thermal stability of the newly synthesized [35s]methionine-labeled p21 in cells transformed by the wild-type ki-msv or by a mutant of ki-msv (ts 371) which is temperature se ... | 1979 | 225570 |
| orthotopic bone induction at sites of moloney murine sarcoma virus inoculation in mice. | moloney murine sarcoma virus (m-msv) induces at the site of inoculation in newborn and adult mice and rats various types of sarcoma, including osteosarcoma. the induced tumours are fatal in newborn, whereas sarcomas developed in adult animals regress spontaneously. the regression is mediated mainly by a cellular response. we have now demonstrated that the presence of sarcomas induced by m-msv is a powerful stimulus for periosteal osteogenesis around tumour masses. orthotopically induced osteogen ... | 1979 | 225678 |
| cytolytic activity of macrophages isolated from primary murine sarcoma virus (msv)-induced tumors. | macrophages isolated from regressing or progressing tumors induced by murine sarcoma virus (msv) were tested for cytolytic activity in a 18-h 51cr release assay. macrophages from the tumors of mice injected 14 days earlier with stocks of msv-producing regressor or progressor tumors had comparable levels of cytotoxicity. however, macrophages from the progressively growing tumors, 50--65 days after the inoculation with the progressor virus, had lower levels of cytotoxicity than those from the regr ... | 1979 | 226482 |
| different rat-derived transforming retroviruses code for an immunologically related intracellular phosphoprotein. | kirsten sarcoma virus (ki-msv) and harvey sarcoma virus (ha-msv) are mouse-rat recombinant viruses that were originally isolated by experimental inoculation of rats with helper-independent mouse type c viruses. we have recently identified in cells transformed by ki-msv or ha-msv, a phosphoprotein, p21, coded for by ki-msv and ha-msv [shih, t.y., weeks, m.o., young, h.a. & scolnick, e.m. (1979) virology 95, in press]. the p21, which is not a virion structural protein, was identified with antisera ... | 1979 | 226970 |
| thermolabile protein kinase molecules in a temperature-sensitive murine sarcoma virus pseudotype. | murine sarcoma virus-associated protein kinases that bind to actin have been purified by affinity chromatography on actin coupled to sepharose. heat inactivation studies showed the presence of thermolabile enzyme activity in pseudotypes containing a temperature-sensitivity mutant of murine sarcoma virus (msv) but not in two independent wild-type msv pseudotypes. studies with sephadex g-75 column fractions showed that a low molecular weight form, approximately 15,000, is the major thermolabile ki ... | 1979 | 226971 |
| loss of proviral dna sequences in a revertant of kirsten sarcoma virus-transformed murine fibroblasts. | a previously described revertant cell line (k-balb sr1212), derived as a single cell clone from a clonal line of murine fibroblasts (k-balb) transformed by a nonproductive infection with the kirsten strain of murine sarcoma virus, has normal morphology and growth kinetics and, unlike the transformed parent cell line, lacks a sarcoma virus that can be rescued. we report here that this reversion correlates with low to undetectable levels of expression of cellular ki-msv-specific rna and a reductio ... | 1979 | 227995 |