| two different factors act separately or together to specify functionally distinct activities at a single transcriptional enhancer. | the expression of genes fused downstream of the moloney murine sarcoma virus (momsv) long terminal repeat is stimulated by glucocorticoids. we mapped the glucocorticoid response element that conferred this hormonal regulation and found that it is a hormone-dependent transcriptional enhancer, designated sg; it resides within dna fragments that also carry a previously described enhancer element (b. levinson, g. khoury, g. vande woude, and p. gruss, nature [london] 295:568-572, 1982), here termed s ... | 1986 | 3023887 |
| interaction of distinct nuclear proteins with sequences controlling the expression of polyomavirus early genes. | the interaction between cellular factors and polyoma virus (py) dna was investigated by using a gel retention assay. nuclear extracts from various cell lines (nih 3t3, nih 3t6, ltk-, f9) contained proteins that formed specific and distinct complexes with py b enhancer fragments of either wild-type or f9-1 mutant origin. the presence of an excess amount of other well-characterized dna sequences, including the py a enhancer, the murine sarcoma virus enhancer, and the simian virus 40 enhancer-promo ... | 1986 | 3023889 |
| nucleotide sequence of the two rat cellular rash genes. | we present the nucleotide sequence of the coding region of the rat c-rash-1 gene and a partial sequence analysis of the rat c-rash-2 gene. by comparing these sequences with the harvey murine sarcoma virus ras gene, we predict that the p21 protein encoded by the harvey virus differs from the cellular c-rash-1-encoded p21 at only two amino acids; those at positions 12 and 59. alterations at each of these positions may play a role in activating the viral p21 protein. the c-rash-2 gene is likely to ... | 1986 | 3023901 |
| temperature-dependent cytocidal effects of moloney murine sarcoma virus. | infection of l6e9 rat myoblasts with moloney murine sarcoma virus (mo-musv) at 37 degrees c resulted in the killing of target cells in less than one week. however, cells infected at 37 degrees c and shifted to 40 degrees c were not killed but underwent morphological transformation and had reduced levels of virus-specific rna. a marked decrease in a cellular 55 kda protein, as judged by immunoblotting, correlated with increased expression of mo-musv rna in infected cells. | 1986 | 3026112 |
| lipoprotein-associated oncornavirus-inactivating factor in the genus mus: effects on murine leukemia viruses of laboratory and exotic mice. | high titers of oncornavirus-inactivating factor (oif) were found previously in sera of laboratory mice. oif is highly active against mouse xenotropic and polytropic envelope recombinant murine leukemia viruses (mulvs) but not against ecotropic mulvs. of the 20 different mouse species or subspecies currently tested, that represent 4 subgenera, no oif was found in the 3 subgenera more distant to the laboratory mouse. in the subgenus mus, 7 of the 8 most distant species had no oif, whereas all the ... | 1987 | 3026614 |
| germ line integration of a murine leukemia provirus into a retroviruslike sequence. | nucleotide sequence analysis of the cellular sequences flanking the integrated ecotropic (mouse-infectious) murine leukemia provirus of balb/c mice indicated that the murine leukemia provirus is integrated in opposing transcriptional orientation within a solo long terminal repeat (ltr) of the vl30 family of endogenous retrovirus-related sequences. to quantify the effect of this integration event on the ability of the ecotropic provirus to be expressed, we constructed recombinant molecules that c ... | 1987 | 3027396 |
| the interaction of retrovirus and chemical carcinogen in experimental colon carcinogenesis. | the isolation and characterization of oncogenes from human colon cancer and the recognition of their homology with the ras gene of the harvey and kirsten strain of murine sarcoma virus (msv) led us to investigate the effect of exogenous msv on 1,2 dimethylhydrazine (dmh)-induced colon carcinoma in rats. dmh, 20 mg base/kg, was injected weekly for 10 weeks into sprague-dawley rats. the moloney murine sarcoma virus (msv-m) was injected (200 focus-forming units) intraperitoneally into 15 rats 48 ho ... | 1987 | 3027910 |
| monoclonal antibody study of the subcellular localization and dna-stimulating activity of murine sarcoma virus-activated transformation-associated proteins. | previously, we reported the monoclonal antibody detection of transformation-associated proteins (tap) in ts110 murine sarcoma virus-transformed normal rat kidney (6m2) cells (chan et al., 1986). in this study, we used the same monoclonal antibody to investigate the subcellular localization, the fate and the mitogenic activity of tap, as well as the correlationship between tap synthesis and the expression of transformation properties of 6m2 cells. it was found that tap were localized in the cytop ... | 1987 | 3027972 |
| increased adenylate cyclase activity in rat thyroid epithelial cells expressing viral ras genes. | the activity of the adenylate cyclase catalytic subunit is higher in harvey and kirsten murine sarcoma viruses-infected thyroid epithelial cells than in uninfected control cells either in the presence of mg2+ alone or following stimulation by mn2+ or forskolin. the higher activity is associated with an increased camp cellular content. the gpp(nh)p and f- anion are more effective positive modulators in the control than in the virus infected cells: these results exclude therefore that the ras p21 ... | 1987 | 3028415 |
| at least two nuclear proteins bind specifically to the rous sarcoma virus long terminal repeat enhancer. | we used the sensitive gel electrophoresis dna-binding assay and dnase i footprinting to detect at least two protein factors (efi and efii) that bound specifically to the rous sarcoma virus (rsv) enhancer in vitro. these factors were differentially extracted from quail cell nuclei, recognized different nucleotide sequences in the u3 region of the rsv long terminal repeat, and appeared to bind preferentially to opposite dna strands as monitored by the dnase i protection assay. the efi- and efii-pr ... | 1987 | 3029568 |
| functional activity in vivo of effector t cell populations. iii. protection against moloney murine sarcoma virus (m-msv)-induced tumors in t cell deficient mice by the adoptive transfer of a m-msv-specific cytolytic t lymphocyte clone. | the functional activity of moloney murine sarcoma virus (m-msv)-specific t lymphocytes in vivo was assayed by the i.v. injection of virus-specific t lymphocytes into t cell-deficient "b mice". virus-specific t lymphocytes generated in mixed lymphocyte tumor cell cultures were transferred i.v. into syngeneic "b mice" injected simultaneously at a distant site with the virus. these experiments indicated that a low dose (1 x 10(6) cultured cells) of infused lymphocytes can afford protection. to defi ... | 1987 | 3030766 |
| structure and expression of mos sequences in spontaneous and moloney murine sarcoma virus-induced yolk sac carcinomas in rats. | facilitation of yolk-sac carcinoma (ysca) development in fetectomized rats by the moloney murine sarcoma virus/murine leukemia virus (mo-msv/mlv) complex was found to be closely associated with the presence of mo-msv sequences in the genomes of the ysca cells. the virus-induced yscas consisted of cells of mono- or oligoclonal origin which always contained in their genomes at least i randomly integrated mo-msv provirus. in yscas which developed in the absence of virus, no rearrangement or amplifi ... | 1987 | 3030942 |
| enhanced sensitivity of skin fibroblasts from neurofibromatosis patients to transformation by the kirsten murine sarcoma virus. a potential laboratory assay for individuals at risk of cancer. | the present work describes a laboratory assay for individuals predisposed to cancer within nf pedigrees. the assay is based on the association between the increased sensitivity of human skin fibroblasts to transformation by the kirsten murine sarcoma virus and predisposition to cancer in clinically affected patients and in otherwise apparently healthy individuals within nf pedigrees. the more sensitive the cells are to transformation by kimsv, the greater the probability that a person from whom ... | 1986 | 3032058 |
| retrovirus infection alters growth factor responses of t lymphocytes. | a murine helper/inducer t cell clone, d10.g4, has been infected with kirsten-murine sarcoma virus (kisv) pseudotyped with an amphotropic murine leukemia virus. the resultant ki-ras-expressing lines (kisv-d10) remain dependent on exogenous factors for continued growth but display distinctly different mitotic responses to certain cytokines as compared to the uninfected parent clone. unlike the parent d10.g4 cells, these kisv-d10 cells can be maintained in vitro indefinitely in the presence of reco ... | 1987 | 3033071 |
| chemically and virally transformed cells able to grow without anchorage in serum-free medium: evidence for an autocrine growth factor. | ba10-ir transformed cells, obtained by treating syrian hamster embryo fibroblasts (hef) with 7-methylbenz(a)anthracene and cultivated for a long period, are highly tumorigenic and grow in suspension as aggregates (spheroids) (levy et al., 1976). they also grow in attached form or as spheroids in serum-free (s-) synthetic medium, without insulin and transferrin, and form anchorage-independent (ai) colonies in this same, but semi-solid, medium. this exceptional phenotype was acquired stepwise, aft ... | 1987 | 3034920 |
| biologic and molecular characterization of two newly isolated ras-containing murine leukemia viruses. | a murine sarcoma virus (msv) was recovered from an (nfs x ns.c58v-1) f1 mouse which developed splenic sarcoma and erythroleukemia 6 months after inoculation with a mink cell focus-inducing murine leukemia virus (mulv) isolated from an nfs mouse infected with a wild mouse ecotropic mulv. the msv, designated ns.c58 msv-1, induced foci of transformation in mouse and rat fibroblasts, and inoculation of mice of various strains 2 weeks of age or younger resulted in erythroleukemia and sarcomatous lesi ... | 1987 | 3035212 |
| nickel-induced heritable alterations in retroviral transforming gene expression. | determination of the mutagenic effects of carcinogenic nickel compounds has been difficult because, like many metals, nickel is poorly or nonmutagenic in procaryotic mutagenicity assays. we attempted to characterize nickel-induced genetic lesions by assessing the effect of nickel chloride on the conditionally defective expression of the v-mos transforming gene in normal rat kidney cells infected with the murine sarcoma virus mutant ts110 (musvts110) retrovirus. musvts110 contains an out-of-frame ... | 1987 | 3037102 |
| rapid and selective alterations in the expression of cellular genes accompany conditional transcription of ha-v-ras in nih 3t3 cells. | hormone treatment of nih 3t3 cells that contain recombinant fusions between the mouse mammary virus long terminal repeat and the v-ras gene of harvey murine sarcoma virus results in conditional expression of the ras p21 gene product. levels of ras mrna and p21 are maximal after 2 to 4 h of hormone treatment. analysis of cellular rna by northern blotting and nuclease s1 protection assays indicates that the expression of two cellular rna species increases with kinetics similar to v-ras: v-sis-rela ... | 1987 | 3039349 |
| contingent replication assay (cra) procedure for rapid isolation of enhancers. | a rapid procedure for the isolation of functional enhancer sequences consists of the construction of a shotgun dna library in sv40-based plasmid shuttle vectors which depend on an enhancer for replication, the replication in monkey (cvi) cells of those vectors into which an enhancer sequence was inserted, the selective cleavage of unreplicated vectors by dpni and the recovery of the replicated vectors by transfection into escherichia coli. we describe conditions for the fusion of protoplasts to ... | 1987 | 3040530 |
| altered junctional permeability between cells transformed by v-ras, v-mos, or v-src. | junctional permeability in normal and transformed nrk cells was quantitatively assessed by microinjecting fluorescent dye into one cell of a pair, digitizing the changes of fluorescence intensity using video analysis techniques, and applying the digital values to a solution of fick's diffusion equation. we show that this approach reliably estimates the junctional permeance of a cell pair. cells that are temperature sensitive for transformation were shown to also be temperature sensitive vis-ă-vi ... | 1988 | 3056028 |
| expression and phenotypic alterations caused by an inducible transforming ras oncogene introduced into rat liver epithelial cells. | although transforming ras oncogenes have been implicated as causative factors in liver cell transformation, the exact function and phenotypic alterations generated by the expression of such transforming genes in liver epithelial cells has yet to be defined. we have utilized a retroviral vector system to deliver an inducible transforming ras gene into normal, anchorage dependent rat liver epithelial cells. the moloney murine sarcoma virus based vector is composed of a dominant selectable marker, ... | 1988 | 3060790 |
| human bronchial epithelial cells neoplastically transformed by v-ki-ras: altered response to inducers of terminal squamous differentiation. | many human bronchial adenocarcinomas have been shown to contain an activated ki-ras oncogene (rodenhuis et al., n. engl. j. med. 317 929-935, 1987). to test the hypothesis that activated ki-ras may be causally related to human bronchial carcinogenesis, v-ki-ras oncogene was transferred into an established human bronchial epithelial cell line, beas-2b, by infection with kirsten murine sarcoma virus (ki-msv) or by transfection with a plasmid containing the transforming region of ki-msv. these cell ... | 1988 | 3067190 |
| regulation of differential processing of mouse immunoglobulin mu heavy-chain mrna. | the switch between the synthesis of membrane-bound and secreted igm during b cell differentiation is accomplished by producing, from a single gene, two alternative forms of mu heavy-chain mrna that differ only in their 3' termini. the precursor mu rna is either polyadenylated at the first poly(a) site, for secreted mu mrna, or spliced between the c4 and m1 exons, for membrane-bound mu mrna, in a mutually exclusive manner. to elucidate the molecular mechanism of the differential processing of mou ... | 1987 | 3108856 |
| sequence and genomic structure of ras homologues dmras85d and dmras64b of drosophila melanogaster. | the ras homologues of drosophila melanogaster located at 85d and 64b on the polytene chromosome map were cloned using the ha-ras gene of harvey murine sarcoma virus as a probe. the genomic sequences of dmras85d and dmras64b were determined and shown to differ from previously published sequences. dmras85d is much more similar to the ha-ras, ki-ras, and n-ras genes than it is to either the dmras64b gene or to the ras genes of saccharomyces cerevisiae. comparison of the dmras85d genomic sequences w ... | 1987 | 3110012 |
| in vitro induction of osteosarcomalike lesion by transformation of differentiating skeletal precursor cells with fbr murine osteosarcoma virus. | this study analyzed the transforming potential of murine viruses in organ cultures of mouse fetal condylar cartilage: finkel-biskis-jinkins-murine sarcoma virus (fbj-musv) and finkel-biskis-reilly-murine sarcoma virus (fbr-musv). it was only the fbr-musv isolated from a radiation-induced osteosarcoma, that induced morphological changes as early as 24 hours following the infection. the latter manifested itself by a marked enlargement of the number of progenitor cells concomitant with an accumulat ... | 1987 | 3119176 |
| guanine nucleotide binding properties of purified v-ki-ras p21 protein produced in escherichia coli. | we have purified the v-ki-ras p21 protein by expression in escherichia coli of a plasmid encoding 189 amino acids of the kirsten murine sarcoma virus oncogene. the purified p21 (over 95%) exhibited a tenfold greater affinity for gtp (1.6 x 10(-7) m) than for gdp (1.1 x 10(-6) m). the preferential binding of v-ki-ras p21 towards gtp was attributed to the faster dissociation rate of gdp from the protein. the affinity of gdp to v-ki-ras p21 decreased with the depletion of mg2+ while that of gtp did ... | 1988 | 3135524 |
| multistep carcinogenesis of normal human fibroblasts. human fibroblasts immortalized by repeated treatment with co-60 gamma rays were transformed into tumorigenic cells with ha-ras oncogenes. | two normal mortal human fibroblast cell strains were transformed into immortal cell lines, susm-1 and kmst-6, by treatment with 4-nitroquinoline 1-oxide (4nqo) and co-60 gamma rays, respectively. these immortalized cell lines showed morphological changes of cells and remarkable chromosome aberrations, but neither of them grew in soft agar or formed tumors in nude mice. the immortal cell line, kmst-6, was then converted into neoplastic cells by treatment with harvey murine sarcoma virus (ha-msv) ... | 1988 | 3140712 |
| effect of recombinant human interleukin 2 on the growth of a balb/c sarcoma induced by moloney murine sarcoma virus. | the effect of in vivo administration of recombinant interleukin 2 (ril2) on the growth of a primary female balb/c sarcoma induced by moloney murine sarcoma virus (m-msv) was studied. although low-dose administration of (6,000 ju/mouse x 14 days) ril2 had no effect on the growth of the tumors, high-dose (15,000-80,000 ju/mouse x 14 days) intraperitoneal inoculation of ril2 induced tumor regression, dose-dependently. tumors in mice which received 80,000 ju/mouse/day of ril2 regressed completely 2 ... | 1988 | 3141331 |
| biochemical properties of a highly purified v-rash p21 protein overproduced in escherichia coli and inhibition of its activities by a monoclonal antibody. | the v-rash oncogene of harvey murine sarcoma virus encodes a 21,000-dalton p21 protein which has been expressed at a high level as a fusion protein in escherichia coli. we have purified the p21 to over 90% in purity without the use of any detergent or protein denaturant. the purified p21 possesses full biochemical activities of gtp/gdp binding, autokinase, and gtpase. scatchard analysis indicates a single class of binding sites with kd values of 0.83 x 10(-8)m for gtp and 1.0 x 10(-8)m for gdp. ... | 1985 | 3162096 |
| neoplastic transformation inactivates specific trans-acting factor(s) required for the expression of the thyroglobulin gene. | the expression of rat thyroglobulin gene is repressed following the transformation of rat thyroid cells with kirsten murine sarcoma virus. the expression of a reporter gene fused to the thyroglobulin promoter is down-regulated in transformed thyroid cells in transient or in stable transfection assays. dnase and exonuclease iii cleavage-protection analysis reveals that a promoter binding activity located at -60 base pairs from the transcription start site is substantially reduced in transformed t ... | 1988 | 3162304 |
| latent transformed growth-inhibiting factor in human malignant effusions. | an inhibitor of soft agar colony formation by a human breast carcinoma-derived cell line was found to be present in latent form in the majority of cytology-positive human malignant effusions. prior to dialysis, addition of human malignant effusions resulted in less than 10% alteration in efficiency of colony formation by the bt-20 human breast carcinoma cell line (mean efficiency 1 colony/4.3 cells plated at 14 days; mean colony diameter greater than 0.8 mm). after dialysis (membrane cutoff of 3 ... | 1988 | 3257164 |
| structural analysis of normal and transforming mil(raf) proteins: effect of 5'-truncation on phosphorylation in vivo or in vitro. | the phosphorylation sites of the cellular proto-oncogene product p71/73c-mil(raf) from quail and from human cells were analyzed by two-dimensional peptide mapping and compared to the sites phosphorylated in proteins encoded by three transforming alleles of c-mil(raf). these alleles all were 5'-truncated resulting from either retroviral transduction (v-mil, v-raf) or promoter insertion mutagenesis (ltr-c-raf). the normal cellular proteins each were phosphorylated in vivo on three major sites, two ... | 1988 | 3274084 |
| multi-step neoplastic transformation of normal human fibroblasts by co-60 gamma rays and ha-ras oncogenes. | as reported previously (namba et al., 1985; namba, 1985), normal human fibroblasts were transformed into immortal cells with abnormal karyotypes by co-60 gamma-ray irradiation. these immortally transformed cells (kmst-6) showed no clonability in soft agar and were not tumorigenic. however, by treatment with ha-ras oncogenes derived from a human lung carcinoma or harvey murine sarcoma virus, the kmst-6 cells acquired elevated clonability in soft agar and transplantability in nude mice. all the tu ... | 1988 | 3287150 |
| comparison of major cytoskeletons among normal human fibroblasts, immortal human fibroblasts transformed by exposure to co-60 gamma rays, and the latter cells made tumorigenic by treatment with harvey murine sarcoma virus. | immortally transformed human fibroblasts in general acquire an epithelial shape, while normal human fibroblasts demonstrate a spindle-shaped feature. in order to investigate this difference, three types of major cytoskeletal elements, namely, f-actin, tubulin, and vimentin of immortal human fibroblasts were morphologically compared with those of normal human fibroblasts. as a result, a significant difference was observed in the distribution and in the number of f-actin fibers between immortal an ... | 1987 | 3305051 |
| myosin isoform expression in rat rhabdomyosarcoma induced by moloney murine sarcoma virus. | myosin isoform expression was analyzed in experimental rhabdomyosarcoma (rms) using monoclonal antibodies (mabs) and immunofluorescence techniques. tumors induced by inoculating newborn rats with moloney murine sarcoma virus (mo-msv) were examined 30-90 days after birth. nine tumors and two lymph node metastases were studied by direct, indirect, and double immunofluorescence assays using a panel of five anti-myosin mabs. the mab bf-45 was specifically reactive with embryonic myosin heavy chain ( ... | 1987 | 3305517 |
| analysis of ras genes and linked viral sequences in rat hepatocarcinogenesis. | after long-term feeding of a choline-devoid diet to rats, the authors analyzed rask, rash, and rasn transcripts and gene structure in livers and liver tumors. they controlled their analysis by studying cell lines derived from chemically induced hepatomas. transcripts from all three genes were elevated in all tumors, but not in the livers from which they arose. the transcript elevations may represent an effect of active cell proliferation in the tumors. clone hihi-3, derived from the kirsten muri ... | 1987 | 3314528 |
| defective hla class ii expression in a regulatory mutant is partially complemented by activated ras oncogenes. | the human b-cell line rj2.2.5, derived by mutagenesis from a burkitt lymphoma cell line and selected for loss of hla class ii antigen expression, was infected with recombinant retroviruses containing either the harvey murine sarcoma virus oncogene v-ha-ras or the human neuroblastoma homolog nras. both activated ras genes partially complemented the regulatory defect in rj2.2.5 and specifically increased the expression of the dr and dq subsets of hla class ii genes. blot-hybridization analysis and ... | 1987 | 3317416 |
| defects in lens fiber differentiation are linked to c-mos overexpression in transgenic mice. | we describe three strains of transgenic mice derived by embryo microinjection of dna consisting of a long terminal repeat (ltr) of moloney murine sarcoma virus (mo-msv) linked to the murine c-mos coding sequences. southern analysis of the genomic dna of these strains suggested that in each case the transgene had integrated at a different chromosomal location. the strains were characterized by dominant changes in secondary lens fiber differentiation. shortly after birth, insufficient elongation o ... | 1987 | 3322940 |
| kinetic analysis of hydrocortisone effect on the neodifferentiation of kirsten murine sarcoma virus-transformed human skin fibroblasts to adipose cells. | here we have demonstrated that transformation of human skin fibroblasts (sf) by the kirsten murine sarcoma virus (kimsv) is associated with their neodifferentiation into preadipose cells. hydrocortisone (hc) and dexamethasone (dx) promoted the transformation/neodifferentiation of preadipocytes into mature fat cells. the effects of hc on the expression of adipocyte-containing foci (acf) and on the total number of transformed foci (ttf) present in kimsv-treated sf cultures were optimal at a concen ... | 1987 | 3442733 |
| mouse and rat cells undergo rapidly inducible changes in polypeptide secretion following infection with kirsten murine sarcoma virus. | characteristic changes in the secreted polypeptides of kirsten murine sarcoma virus (kimsv) transformed mouse and rat cell lines could be detected 48 hours after infection of phenotypically normal cells with this virus and correlated with detection of the kimsv encoded polypeptide p21. | 1987 | 3453098 |
| ouabain sensitivity is linked to ras -transformation in human hos cells. | mouse cells transformed by the retroviral oncogene v-ki- ras are significantly more sensitive to the toxic effects of 1mm ouabain than are their nontransformed counterparts. we have extended these findings to a human cell line (hos). hos cells (atcc crl 1543) are relatively resistant to treatment with 1 microm ouabain while khos cells (transformed by kirsten murine sarcoma virus) are extremely sensitive. two flat revertant cell lines isolated from the khos line and lacking the v- ras gene sequen ... | 1986 | 3458466 |
| rna polymerase specificity of mrna production and enhancer action. | to examine the rna polymerase (ec 2.7.7.6) specificity of rna maturation/utilization and transcriptional enhancement, we constructed a chimeric plasmid (ppoli-cat) in which a promoter for mouse rrna gene transcription was placed adjacent the coding sequences for chloramphenicol acetyltransferase (cat; ec 2.3.1.28). a number of other constructs, including plasmids also containing a murine sarcoma virus enhancer or lacking any natural eukaryotic promoter sequences, were also prepared. in apparent ... | 1986 | 3462718 |
| modification of steroidogenesis in rat adrenocortical cells transformed by kirsten murine sarcoma virus. | adrenal fibroblasts from adult rats acquire some adrenocortical parenchymal characteristics as a consequence of transformation in early passage with kirsten murine sarcoma virus. to further define the effects of kirsten murine sarcoma virus-induced transformation on the steroid enzymes of these cells, we investigated the capacity of kirsten murine sarcoma virus-transformed and untransformed adrenocortical fibroblasts to convert progesterone to c19 and c21 steroid metabolites. over 95% of metabol ... | 1987 | 3469015 |
| monoclonal igm antibodies that inhibit primary moloney murine sarcoma growth. | monoclonal igm antibodies with specificity for moloney murine sarcoma virus (m-musv)-moloney murine leukemia virus (m-mulv) from two hybridoma clones have been isolated and characterized. the monoclonal antibodies have specificity for a cytoplasmic and cell surface friend-moloney-rauscher group-specific antigen. immunoelectron microscopy revealed antibody binding to the surface of virus-expressing cells but not to the budding virus particles. treatment of m-musv-injected mice with monoclonal igm ... | 1987 | 3469466 |
| alteration of glycolipids in ras-transfected nih 3t3 cells. | glycosphingolipid alterations upon viral transformation are well documented. transformation of mouse 3t3 cells with murine sarcoma viruses results in marked decreases in the levels of gangliosides gm1 and gd1a and an increase in gangliotriaosylceramide. the transforming oncogenes of these viruses have been identified as members of the ras gene family. we analyzed nih 3t3 cells transfected with human h-, k- and n-ras oncogenes for their glycolipid composition and expression of cell surface gangli ... | 1987 | 3476926 |
| detection of an intracellular transforming protein (v-ki-ras p21) using the flow activated cell sorter (facs). | the transforming protein coded for by the ki-ras oncogene, v-p21, localizes at the cytoplasmic face of the plasma membrane. a method is presented whereby the appearance of v-p21 in kirsten murine sarcoma virus-transformed cells can be detected by flow cytometry, using a monoclonal antibody to v-p21 and methods modified from immunofluorescence microscopy. the method is sufficiently sensitive to differentiate between cellular and viral p21 levels, to detect small subpopulations of virus-transforme ... | 1986 | 3490470 |
| electric field-mediated gene transfer (electroporation) into mouse friend and human k562 erythroleukemic cells. | electroporation, the technique of electric field mediated gene transfer, was evaluated as a means of introducing and expressing genes into mouse friend and human k562 erythroleukemic cells. long-term (stable) gene expression in both friend and k562 cells was measured using the recombinant plasmid homer 6, which carries the aminoglycoside phosphotransferase (aph) gene as a selectable marker under the transcriptional control of the moloney murine sarcoma virus long terminal repeat promoter/enhance ... | 1987 | 3507389 |
| expression of p21 ras oncoproteins in human cancers. | the expression of proteins encoded by ras oncogenes was examined in 52 fresh human tumors of 19 different types using antibodies generated to different peptide domains of ras proteins of molecular weight 21,000 (p21). proteins related to ras genes were detected in 90% of tested tumors. in 21% of tumors there were high levels of ras p21 of greater than 40% of the level in a harvey murine sarcoma virus transformed cell line. predominance of either cellular ha-ras or other ras p21s was found in 20 ... | 1986 | 3510727 |
| insulin stimulates the phosphorylation level of v-ha-ras protein in membrane fraction. | insulin was found to stimulate the phosphorylation of the 21,000-dalton protein encoded by the ras oncogene of harvey murine sarcoma virus in membrane fraction both in vivo and in vitro. when the human ras proteins expressed in e. coli were reconstituted with purified human insulin receptor, gtpase activity of normal or its mutated oncogenic ras protein was not stimulated by the addition of insulin. likewise, tyrosine kinase activity or insulin binding capacity of the receptor was not influenced ... | 1987 | 3555484 |
| lactate dehydrogenase-elevating virus induces anti-golgi apparatus antibodies. | a recently described autoantibody-inducing agent in mice was further characterized. tentatively designated agia (anti-golgi apparatus-inducing agent), this agent has previously been shown to cause antibody production against golgi apparatus (ga) antigen of cells from different vertebrate species as well as against tumour surface antigen of the moloney murine sarcoma virus-non-producer transformant sac. it was shown to possess the properties characteristic of lactate dehydrogenase-elevating virus ... | 1987 | 3598563 |
| human epidermal keratinocytes retain radiation resistance following in vitro immortalization and malignant transformation. | the radiobiology of human tumors suggests that multiple factors are involved in clinical radioresponsiveness. to date, no direct experimental evidence is available to correlate intrinsic cellular radiosensitivity with the steps of malignant transformation. we developed an in vitro multistage model of epithelial neoplasia using human epidermal keratinocytes to examine the effects of malignant transformation on radiation response. these cells were first immortalized as a result of infection with a ... | 1987 | 3659288 |
| revertants of v-fos-transformed fibroblasts have mutations in cellular genes essential for transformation by other oncogenes. | morphologic revertants of fbj murine sarcoma virus (v-fos)-transformed rat-1 fibroblasts were isolated using a novel selection procedure based on prolonged retention of rhodamine 123 within mitochondria of v-fos-transformed versus normal fibroblasts. two classes of revertants were isolated: class i revertants have sustained mutations in cellular genes, and a class ii revertant has a nonfunctional v-fos provirus. somatic-cell hybridization studies suggested that the revertant phenotype was recess ... | 1987 | 3664639 |
| effects of ouabain on nih/3t3 cells transformed with retroviral oncogenes and on human tumor cell lines. | both murine and human cell lines transformed by the v-ki-ras gene have been shown to be much more sensitive to the toxic effects of the cardiac glycoside ouabain than their respective controls. this differential toxicity has previously been used in the isolation of flat revertant clones from populations of kirsten murine sarcoma virus transformed nih/3t3 cells. here, we have undertaken a further characterization of this phenomenon in murine and human tumor cells. two different techniques, a 51cr ... | 1987 | 3679592 |
| pathogenicity of retroviruses containing either the normal human c-ha-ras1 gene or its mutated form derived from the bladder carcinoma ej/t24 cell line. | cellular ras oncogenes transduced by retroviruses carry mutations in amino acids 12, 59 and 122. similar mutations have been observed in ras oncogenes activated during induction of neoplasia in both humans and experimental animals. the unmutated normal rat or human c-ha-ras-1 genes have the ability to transform nih 3t3 cells in culture when activated by a rna synthesis promoter. these findings raise the question of whether the mutations are necessary for the ras oncogenes to induce the neoplasti ... | 1985 | 3842394 |
| efficient transcription of a protein-coding gene from the rna polymerase i promoter in transfected cells. | the activity of the mouse ribosomal promoter was examined after fusion to the gene coding for chloramphenicol acetyltransferase (cat) and transfection into mouse cells. very little cat enzyme but high levels of cat-specific rna correctly initiated at the ribosomal dna start site were synthesized. the amount of specific transcripts was neither influenced by long stretches of upstream spacer sequences nor by the insertion of the moloney murine sarcoma virus enhancer. the deletion mutant pmr delta- ... | 1985 | 3856225 |
| infectivity of friend murine leukemia virus for hamster cells. | hamster-adapted friend murine leukemia virus (f-mulv) infected hamster cells and produced an xc-positive progeny. however, the sensitivity of hamster-adapted f-mulv's to hamster cells was about 100 times lower than that to mouse cells. hamster cells chronically infected with f-mulv in vitro produced progeny virus in titers comparable to those in similarly infected mouse cells. xenotropic and amphotropic murine leukemia virus can infect hamster cells when phenotypically mixed with the f-mulv. mur ... | 1985 | 3857383 |
| plasmid-induced "hit-and-run" tumorigenesis in chinese hamster embryo fibroblast (chef) cells. | the chinese hamster embryo fibroblast cell line chef/18 is readily transfected by plasmid dna. in the present transfection studies with chef/18 cells, focus formation induced by plasmids containing the mutant human c-ha-ras gene ej was compared with that of control plasmids without the ej insert. the focus-forming activity of the transfected plasmid j132, a recombinant of the harvey murine sarcoma virus ltr and the normal human c-ha-ras1 in pbr322, also was assessed. foci were recovered after tr ... | 1985 | 3857618 |
| t-cell regulation of erythropoiesis during acute lymphoblastic leukemia. | how and where erythropoiesis is maintained during advanced leukemic disease is an important and, as yet, unresolved question in hematology. to address the potential role of t-lymphocytes as cells that regulate cfu-e differentiation during leukemogenesis, an experimental model of disease has been developed in inbred balb/c mice. specifically, three-week-old balb/c by mice were injected with murine sarcoma virus-murine leukemia virus-moloney (msv-mulv-m), which resulted 6-8 months later in the dev ... | 1985 | 3871705 |
| transformation of mononuclear phagocytes in vivo and malignant histiocytosis caused by a novel murine spleen focus-forming virus. | the study of retrovirus-induced leukaemias in mice is a powerful tool for the elucidation of the normal regulation of the haematopoietic system. the acute murine spleen focus-forming viruses (sffv) can be classified according to the haematopoietic lineage on which they exert their effects in the adult mouse. here we report a new sffv isolate, the af-1 virus, with the novel ability to transform cells of the mononuclear phagocyte lineage. the virus was isolated from sarcomas that were induced on p ... | 1985 | 3873013 |
| characterization of gp85gag as an antigen recognized by moloney leukemia virus-specific cytolytic t cell clones that function in vivo. | the gag membrane protein gp85gag, encoded by moloney murine leukemia virus (m-mlv), was identified as a target molecule recognized by moloney murine sarcoma virus--m-mlv (m-msv--m-mlv)-specific cytolytic t lymphocyte (ctl) clones. target cells infected with ab-x-mlv, an m-mlv-derived mutant virus not encoding gp85gag, were not lysed by the ctl clones. the same ctl clones were shown previously to induce the destruction of m-mlv-induced tumor cells in the peritoneal cavity. we have now characteriz ... | 1985 | 3891902 |
| product of the cellular oncogene, c-fos, observed in mouse and human tissues using an antibody to a synthetic peptide. | the transforming gene of the osteosarcoma-producing fbj murine sarcoma virus, v-fos, is homologous to a normal cellular gene, c-fos, in vertebrate species. transcripts from the c-fos proto-oncogene accumulate to very high levels in late gestational mouse and human extra-embryonic tissues. we now report that these rna transcripts are translated in these tissues. rabbits were immunized with a synthetic peptide whose sequence is common to both c-fos and v-fos. after affinity purification on an immu ... | 1985 | 3894012 |
| p21ras. heterogeneous localization in transformed cells. | the cellular targets for the kirsten murine sarcoma virus (kimsv)-transforming protein, p21ras, are unknown. other studies have indicated that the mature form of p21 is distributed diffusely on the cytoplasmic face of the plasma membrane. however, after fixation without buffer washes, indirect immunofluorescent staining of sparse cultures revealed a particularly well preserved cellular architecture and a strikingly heterogeneous subcellular distribution of p21 in transformed normal rat kidney (n ... | 1985 | 3896830 |
| expression of intact ki-ras p21 protein in escherichia coli. | we have constructed recombinant plasmids capable of expressing in escherichia coli the intact ras p21 protein encoded by kirsten murine sarcoma virus. the ki-ras gene was inserted into an expression vector carrying the e. coli tryptophan promoter and e. coli lipoprotein transcriptional terminator. the resulting plasmids direct the synthesis of large quantities of p21 protein, which represented 20% of the total cellular protein. the ki-ras p21 protein is immunoprecipitated with monoclonal antibod ... | 1985 | 3904744 |
| the mitogenic/oncogenic p21 ki-ras protein stimulates adenylate cyclase activity early in the g1 phase of nrk rat kidney cells. | tsk-nrk rat cells infected with a temperature-sensitive mutant of the kirsten murine sarcoma virus were arrested in the g0/g1 phase of their cell cycle by incubation in serum-deficient medium at a temperature (41 degrees c) which inactivates the virus' abnormally thermolabile mitogenic/oncogenic 21 kda (p 21) ras protein product. reactivating the viral ras protein by lowering the temperature to a permissive 36 degrees c rapidly (within 1 hour) stimulated adenylate cyclase, sensitized the enzyme ... | 1985 | 3904756 |
| characterization and developmental expression of a drosophila ras oncogene. | we cloned a drosophila melanogaster ras gene (dmras64b) on the basis of its homology to the ras oncogen from harvey murine sarcoma virus. this gene mapped at chromosomal position 64b on the left arm of the third chromosome. sequencing of dmras64b revealed extensive amino acid homology with the proteins encoded by the human and saccharomyces cerevisiae ras genes. the coding region of the drosophila gene is interrupted by two introns located in different positions with respect to its human counter ... | 1985 | 3921827 |
| the ras oncogene product p21 is not a regulatory component of adenylate cyclase. | harvey (ha-msv) and kirsten (ki-msv) murine sarcoma viruses induce tumours in animals and transform various cells in culture because of the expression of the ras oncogene product, p21 (ref. 1). proto-oncogenes homologous with these genes are highly conserved evolutionarily and activated ras oncogenes have been detected in many human cancers. whether c-ras oncogenes are directly responsible for human carcinogenesis is uncertain; however, it is clear that p21 mediates virus-induced transformation, ... | 1985 | 3929144 |
| anti-tumour effect of humoral and cellular immunities mediated by a bacterial immunopotentiator, lactobacillus casei, in mice. | administration of a mixture containing lactobacillus casei yit 9018 (lc9018) and methylcholanthrene-induced fibrosarcoma (meth a) cells into the peritoneum of syngeneic balb/c mice suppressed the tumour growth and protected the mice from tumour death. with the appearance of the anti-tumour activity, serum complement-dependent tumour cytotoxic (cdc) antibody was induced on the 5th day after the administration as a result of the adjuvant effect. the cytotoxic antibody was not found in serum on the ... | 1985 | 3930065 |
| multistep process of neoplastic transformation of normal human fibroblasts by 60co gamma rays and harvey sarcoma viruses. | as reported previously (namba et al., 1985), normal human fibroblasts were transformed by 60co gamma-ray irradiation into immortal cells with abnormal karyotypes. these transformed cells (kmst-6), however, showed a low cloning efficiency in soft agar and no transplantability. however, upon treatment with harvey murine sarcoma virus (ha-msv), the cells acquired elevated clonability in soft agar and transplantability in nude mice. ha-msv alone, however, did not convert normal human fibroblasts int ... | 1986 | 3949423 |
| mmc-e cells--origin and changes in karyotype accompanying malignant transformation. | karyotype analysis of an established nontumorigenic cell line (mmc-e) indicated that the cells are of rat origin instead of mouse, as interpreted earlier. this cell line, now termed re (rat epithelial) had a karyotype of 39,x,-5,-15,-?16,+t(3q11q) in the stem line. there was also one subline that had a karyotype of 40,x,-5,-15,-?16,+t(3q11q), +?t(5;?). chromosome changes and frequency of sister chromatid exchanges (sces) were studied from seven malignantly transformed re cell lines. these includ ... | 1985 | 3971317 |
| transformation of human bronchial epithelial cells transfected by harvey ras oncogene. | transfection of normal human bronchial epithelial (nhbe) cells with a plasmid carrying the ras oncogene of harvey murine sarcoma virus (v-ha ras) changed the growth requirements, terminal differentiation, and tumorigenicity of the recipient cells. one of the cell lines isolated after transfection (tbe-1) was studied extensively and shown to contain v-ha ras dna. total cellular rna from tbe-1 cells hybridized to v-ha ras structural gene fragment probes five to eight times more than rna from paren ... | 1985 | 3975607 |
| expression of c-mos proto-oncogene transcripts in mouse tissues. | valuable information about proto-oncogenes and their physiological function has been obtained by studying their expression in normal cells. however, expression of the c-mos gene, the cellular homologue of the transforming gene of moloney murine sarcoma virus, has not been detected in normal mouse cells or tissues. the conservation of the c-mos open reading frame strongly indicates that the gene must function during some portion of the animal life cycle, and other lines of evidence suggested to u ... | 1985 | 4000280 |
| expression of glucagon sensitivity by transformed mdck cells normally unresponsive to glucagon: early commitment to differentiation. | a cloned line of canine kidney cells (mdck) transformed with harvey murine sarcoma virus, in contrast to the parental, untransformed line, expressed glucagon sensitivity only under controlled culture conditions. the glucagon sensitivity of transformed mdck cells appeared after 10 days of culture if plated at less than 100,000 cells/dish or after 3 days if cells were plated at greater than 300,000 cells/dish. as there was no effect of conditioned medium from glucagon-sensitive cells on insensitiv ... | 1985 | 4055913 |
| depressed interferon synthesis in skin fibroblasts from lung cancer patients. | skin fibroblast cell cultures, derived from male adult lung cancer patients, an adult control population, and a newborn population were examined for their susceptibility to transformation with kirsten murine sarcoma virus and their ability to respond to an interferon inducer (poly i x poly c). an association between sensitivity to viral transformation and induction of interferon was observed. cultures derived from lung cancer patients demonstrated an increased sensitivity to virus transformation ... | 1985 | 4056491 |
| sarcoma viruses carrying ras oncogenes induce differentiation-associated properties in a neuronal cell line. | the growth-promoting and/or differentiation-blocking activities of kirsten (ki-msv) or harvey murine sarcoma virus (ha-msv) on various types of cells in vitro are well documented. here we report an unexpected effect of these viruses on a rat phaeochromocytoma cell line, pc12. pc12 cells, which multiply indefinitely in growth medium, are known to respond to nerve growth factor (ngf) by cessation of cell division and expression of several properties resembling those of differentiated sympathetic n ... | 1985 | 4058592 |
| characteristics of 30-, 63-, and 89-kilodalton proteins whose secretion from mouse fibroblasts is altered by beta-interferon. | quiescent mouse balb/c-3t3 cells were treated with beta-interferon to induce the secretion of proteins of 30 and 89 kda and with a platelet-derived growth factor preparation to induce the secretion of a 63-kda protein. to label the secreted proteins the cultures were supplemented with [35s]methionine after addition of the inducer. the proteins in the culture fluid were fractionated resulting in a radioactively pure 63-kda protein and 30- and 89-kda protein preparations with residual minor radioa ... | 1985 | 4066715 |
| alterations in the susceptibility of cultured mouse cells to transformation by murine sarcoma virus (harvey). | | 1971 | 4107845 |
| rifamycin derivatives strongly inhibiting rna leads to dna polymerase (reverse transcriptase) of murine sarcoma viruses. | | 1972 | 4114001 |
| revertants of mouse cells transformed by murine sarcoma virus. i. characterization of flat and transformed sublines without a rescuable murine sarcoma virus. | | 1972 | 4117128 |
| isolation of temperature-sensitive mutants of murine sarcoma virus. | three separate murine sarcoma virus nonproducer cell lines have been isolated which are temperature sensitive for the maintenance of transformation. in each case, a viral rather than a cellular genetic mutation is the reason for the temperature-sensitive effect. superinfection of one of the mutants with murine leukemia virus overcomes the temperature-sensitive change in the transformed state. | 1972 | 4117345 |
| major group-specific protein of rat type c viruses. | the major internal protein of a rat type c virus pseudotype of murine sarcoma virus, msv(ralv), was purified by isoelectric focusing (pi = 8.6) and used to prepare antibody in guinea pigs. the protein was identified by its reaction with antisera reactive with the mammalian type c virus group-specific (gs) antigenic determinant, gs-3. the guinea pig antisera mainly contained species-specific (gs-1) antibody for reactions in gel diffusion with other type c viruses were limited to those of rat orig ... | 1972 | 4117346 |
| in vitro transformation of canine embryo cells by murine sarcoma virus (kirsten). | | 1973 | 4121083 |
| isolation of rd-114-like oncornavirus from a cat cell line. | a clone of cells derived from a continuous line of cat cells (ccc) spontaneously produced an rna c-type virus (ccc virus) which did not have the group-specific antigen of the standard strains of feline leukemia viruses but did have that of the rd-114 virus. single-hit infection of a virus yielding ccc cell with only the feline leukemia virus pseudotype of murine sarcoma virus [msv(felv)] resulted in the release of a pseudotype of msv coated with the ccc virus envelope. host range, transmission o ... | 1973 | 4123287 |
| mutants of nonproducer cell lines transformed by murine sarcoma virus. ii. relationship of tumorigenicity to presence of viral markers and rescuable sarcoma genome. | tumorigenic and nontumorigenic mutants induced by a single 5'-bromodeoxyuridine (brdu) treatment of a nonproducer (np) tumorigenic cell line were isolated and characterized. among the cloned derivatives were examples of virus-free and sarcoma virus-producing cell lines. oncogenicity did not correlate with production of virus or ease of rescue of the sarcoma genome. all lines, including nononcogenic derivatives, retained the sarcoma genome. phenotypic reversion of some cell mutants was observed a ... | 1973 | 4124209 |
| revertants of mouse cells transformed by murine sarcoma virus. ii. flat variants induced by fluordeoxyuridine and colcemid. | | 1973 | 4126841 |
| effects of polyadenylic acids on functions of murine rna tumor viruses. | single-stranded polyribonucleotides, which competitively inhibit murine rna tumor virus reverse transcriptase in vitro, were tested as inhibitors of various virus functions in cell culture. the compounds had two concentration-dependent effects. at high concentrations (100 mug/ml), both poly(adenylic acid) [poly(a)] and poly(2'-o-methyladenylic acid) [poly(am)] inhibited the uptake of radioactively labeled leukemia virus by swiss mouse embryo cells, but neither had a similar effect on sindbis vir ... | 1973 | 4128377 |
| cell-mediated reaction against tumors induced by oncornaviruses. i. kinetics and specificity of the immune response in murine sarcoma virus (msv)-induced tumors and transplanted lymphomas. | | 1972 | 4128690 |
| transformation assay for murine sarcoma viruses using a simian virus 40-transformed human cell line. | | 1974 | 4129832 |
| specificity of the dna product of rna-dependent dna polymerase in type c viruses. ii. quantitative analysis. | a number of mammalian type c viruses were analyzed for relatedness by the technique of dna.rna hybridization. viral dnas were prepared in single-stranded form from complexes with 70s viral rna formed during endogenous polymerase reactions. extent of hybridization was assayed with the single-strand nuclease (s-1) from aspergillus oryzae. results obtained indicated a high degree of viral specificity, with significant cross-reactions being observed only with viruses obtained from within a species, ... | 1973 | 4129928 |
| properties of 3t3 cells transformed by murine sarcoma virus in the absence of replicating murine leukemia helper virus. | | 1973 | 4130395 |
| murine sarcoma virus-transformed nonproducer rat cell lines resistant to type c-virus infection. | | 1973 | 4131817 |
| revertants of mouse cells transformed by murine sarcoma virus. 3. metastable expression of virus functions in revertants retransformed by murine sarcoma virus. | | 1974 | 4133134 |
| antigens of tumours induced by naturally occurring murine sarcoma virus (msv-fbj). ii. detection of cell-surface antigens by indirect membrane immunofluorescence. | | 1974 | 4133783 |
| in utero tumor induction by murine sarcoma virus (moloney) in the rat. ii. histological and ultrastructural characteristics. | | 1973 | 4133944 |
| wide host range of murine sarcoma virus. | | 1973 | 4134009 |
| expression of the defective "s plus l-" type murine sarcoma virus genome in human amnion and lung cells. | | 1974 | 4134499 |
| separation of ribonuclease h and rna directed dna polymerase (reverse transcriptase) of murine type-c rna tumor viruses. | ribonuclease h (rna.dna-hybrid ribonucleotidohydrolase, ec 3.1.4.34) has been reported to copurify with reverse transcriptase (rna directed dna polymerase) of rna tumor viruses. in addition, viral specific ribonuclease h and reverse transcriptase of avian type-c viruses are thought to be part of the same polypeptide. in this report we show that a fraction of the ribonuclease h activity from rauscher murine leukemia and kirsten murine sarcoma viruses was separated from reverse transcriptase by an ... | 1974 | 4134616 |
| baboon virus isolate m-7 with properties similar to feline virus rd-114. | a virus (m-7) isolated from baboon placental tissue demonstrates many similarities to endogenous feline virus rd-114. immunodiffusion analysis shows a group-specific antigen (gs-1) line of identity between m-7 and rd-114. anti-rd-114 dna polymerase igg inhibits m-7 polymerase by 57% compared to 97% for rd-114. m-7 virus has helper activity as demonstrated by rescue of murine sarcoma virus (msv) from sarcoma-positive leukemia-negative human amnion cells. the host range of the rescued m-7 pseudoty ... | 1974 | 4134740 |
| viral rna of murine sarcoma virus produced by a hamster-mouse somatic cell hybrid. | | 1974 | 4135225 |
| specificity of the dna product of rna-dependent dna polymerase in type c viruses: 3. analysis of viruses derived from syrian hamsters. | dna transcripts were prepared from three related viruses of hamster and analyzed by interviral hybridization and by reaction with cellular dna. a virus (g-halv), isolated from a dimethylbenzanthraceneinduced tumor cell in graffi hamsters, contained nucleic acid sequences highly specific for hamster cell dna and did not react with mouse cell dna nor did its transcript show homology (<5%) with mouse or rat viral rnas. the hamster-specific sarcoma virus, b-34, isolated by bassin and coworkers from ... | 1974 | 4137938 |
| an immunoelectron microscopy study of soehner-dmochowski murine sarcoma virus following passage in rats and hamsters. | | 1974 | 4138610 |