Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
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| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| site-selective camp analogs induce nuclear translocation of the rii camp receptor protein in ha-musv-transformed nih/3t3 cells. | site-selective camp analogs, depending on the position of their substituents on the adenine ring, selectively bind to either site 1 or site 2 of the known camp binding sites of protein kinase. treatment of harvey murine sarcoma virus-transformed nih/3t3 cells with such site-selective analogs results in growth inhibition and phenotypic reversion, and the combination of a c-8 thio or halogen analog (site 1 selective) with an n6 analog (site 2 selective) produces a synergistic effect. we report her ... | 1987 | 2826232 |
| amplification and rearrangement of the kirsten ras oncogene in virus-transformed balb/c 3t3 cells during malignant tumor progression. | analyses of the cellular and viral kirsten ras genes (c-ki-ras and v-ki-ras, respectively) during malignant tumor progression were performed by using kirsten murine sarcoma virus-transformed balb/c 3t3 cells that harbor a replication-defective provirus. after injection into athymic nude mice by four different routes, primary tumors and secondary lung metastases were isolated, adapted to in vitro growth, and analyzed for dna levels and mrna expression of both genes for comparison with the origina ... | 1987 | 3474646 |
| continuing rearrangement of immunoglobulin and t-cell receptor genes in a ha-ras-transformed lymphoid progenitor cell line. | the arrangement of immunoglobulin genes has been examined in a series of lymphoid cell lines transformed with the harvey murine sarcoma virus. one cell line, haftl-1, expresses antigenic markers characteristic of b-lymphoid cells and undergoes frequent rearrangement at the jh locus (where j = joining and h = heavy chain) during propagation in culture. by molecular cloning and nucleotide sequence determination, these rearrangements were found to represent the earliest postulated step in heavy cha ... | 1987 | 3470759 |
| murine retrovirus-induced malignant histiocytosis, an experimental model for the disease in humans. | the hematopoietic disregulation in adult mice induced by the malignant histiocytosis sarcoma virus (mhsv) and the harvey murine sarcoma virus (ha-musv), which both possess c-ha-ras-related oncogenic sequences, was investigated. spleen focus formation induced by mhsv and ha-musv was not restricted by the fv-2 resistance locus in congenic ddd and c57bl/6 mice, unlike leukemogenesis induced by friend virus, rauscher virus, and the myeloproliferative sarcoma virus (mpsv). c57bl/6 mice were much more ... | 1987 | 2823012 |
| altered metabolism and cell surface expression of glycosphingolipids caused by vitamin e in cultured murine (k3t3) reticulum sarcoma cells. | vitamin e caused a generalized reduction in the metabolism and cell surface expression of glycosphingolipids (gsl) in cultured kirsten murine sarcoma virus-transformed nonproducer (k3t3) cells. metabolism of gangliosides was decreased two- to fourfold in cells treated for 72 hr with 1 and 2 micrograms/ml but not with 12 micrograms/ml vitamin e compared to control cultures. this was demonstrated by a quantitative reduction in precursor 3h-galactose label incorporated in ganglioside fraction and f ... | 1986 | 3540508 |
| mutational analysis of a ras catalytic domain. | we used linker insertion-deletion mutagenesis to study the catalytic domain of the harvey murine sarcoma virus v-rash transforming protein, which is closely related to the cellular rash protein. the mutants displayed a wide range of in vitro biological activity, from those that induced focal transformation of nih 3t3 cells with approximately the same efficiency as the wild-type v-rash gene to those that failed to induce any detectable morphologic changes. correlation of transforming activity wit ... | 1986 | 3023943 |
| ectopic hematopoiesis in peritoneal tumor nodules induced by the myeloproliferative sarcoma virus in dba/2 mice. | tumor nodules composed of fibroblasts, large undifferentiated cells, granulocytes, and small lymphocytes develop in the spleens of adult dba/2 mice infected with the myeloproliferative sarcoma virus (mpsv). they spread thereafter in the organism, and at the terminal stage of the disease they are especially numerous on the peritoneal membrane. the present study, performed on those tumor nodules to avoid contamination by exogenous hematopoietic cells, demonstrated that they were sites of granulopo ... | 1986 | 3456070 |
| [fatty acid content in the muscles and liver of mice developing sarcomas induced by 3-methylcholanthrene and moloney murine sarcoma virus]. | a comparative analysis was made for the fatty acid composition of lipids in the malignant muscular tissue, muscle and liver under blastomogenesis induced in mice by the moloney sarcoma virus and 3-methylcholanthrene. the relation of the found changes in the fatty acid composition to the blastomogenesis stages is shown. the development of the tumour node is accompanied by a decrease of the fatty acid amount in the animal tissues and by its increase in the tumour. a spontaneous regression of the m ... | 1986 | 3948758 |
| direct identification of palmitic acid as the lipid attached to p21ras. | p21v-h-ras, the transforming protein of harvey murine sarcoma virus, contains a covalently attached lipid. using thin-layer chromatography, we identified the acyl group as the 16-carbon saturated fatty acid palmitic acid. no myristic acid was detected in fatty acids released from in vivo-labeled p21v-h-ras. the p21v-k-ras protein encoded by kirsten sarcoma virus was also palmitylated. the processing and acylation of p21v-k-ras however differed from that of p21v-h-ras. three forms of [3h]palmitic ... | 1986 | 3023817 |
| 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 |
| temperature-sensitive splicing defect of ts110 moloney murine sarcoma virus is virus encoded. | ts110 moloney murine sarcoma virus (mo-musv)-nonproductively infected cells (6m2) have a transformed phenotype at 28 to 33 degrees c and a normal phenotype at 39 degrees c. at temperatures permissive for transformation, 6m2 cells contain p58gag produced from the 4.0-kilobase (kb) viral rna genome and p85gag-mos translated from a 3.5-kb spliced mrna. at 39 degrees c, only the 4.0-kb rna and its product p58gag are detected. two temperature-sensitive defects have been observed in ts110-infected 6m2 ... | 1986 | 3001353 |
| molecular basis underlying phenotypic revertants of moloney murine sarcoma virus musvts110. | we examined the molecular basis for phenotypic reversion in cells infected with a transformation mutant of murine sarcoma virus, musvts110. in musvts110-infected nrk cells (6m2 cells), the manifestation of the transformed phenotype at 33 degrees c and the normal phenotype at 39 degrees c is governed by thermosensitive splicing of the musvts110 primary transcript, a 4.0-kilobase (kb) rna which contains the gag and mos genes joined out of frame. at 33 degrees c, selectively, the 4.0-kb rna is proc ... | 1986 | 3001354 |
| 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 |
| 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 |
| 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 |
| 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 |
| functions of the mos oncogene family and associated gene products. | the mos oncogene present in moloney murine sarcoma virus is one of the oldest known oncogenes, yet the identification of its biochemical function both in transformation and as a cellular proto-oncogene has been elusive. only recently have low levels of c-mos transcripts been detected in a specific group of mouse tissues. the c-mos gene is implicated in tumorigenicity by its activation by the insertion of the intracisternal a particle genome in a mouse plasmacytoma. the murine c-mos gene is capab ... | 1986 | 2946405 |
| point mutations in the u3 region of the long terminal repeat of moloney murine leukemia virus determine disease specificity of the myeloproliferative sarcoma virus. | the myeloproliferative sarcoma virus (mpsv) is made up entirely of sequences derived from the moloney murine leukemia virus (mo-mulv) and the cellular mos oncogene. as other members of the moloney murine sarcoma virus (mo-musv) family, mpsv transforms fibroblasts in vitro and causes sarcomas in vivo. in addition, however, mpsv also causes an acute myeloproliferative disease in adult mice. the mos oncogene is essential for its transforming capacity, but sequences specific to the long terminal rep ... | 1986 | 3016984 |
| the effect of cerulenin on the synthesis of the precursor gag polyprotein in defective murine leukemia and sarcoma virus producing cell lines. | the effect of cerulenin, an inhibitor of de novo fatty acid (and cholesterol) biosynthesis, on the synthesis of the precursor gag polyprotein, pr65gag in a defective murine leukemia virus (334c) producing murine cell line (3je) and a defective murine sarcoma virus (gazdar) producing hamster cell line (htg-2) was examined. in contrast to moloney murine leukemia virus (m-mulv) producing cell lines (mjd-54, clone 2) the amount of the pr65gag remaining in the presence of cerulenin (20 micrograms/ml) ... | 1986 | 3019002 |
| modulation by normal serum factors of kirsten murine sarcoma virus-induced transformation in adult rat cells infected in early passage. | adult rat adrenal cells, infected with kirsten murine sarcoma virus in early passage, transform consistently in 10% fetal bovine serum (fbs)-supplemented medium. substitution of 3% horse serum (hs) for fbs reverses early foci and delays transformation. the influence of the serum on dna synthesis, anchorage dependence, tumorigenicity, and subcellular mr 21,000 transforming protein (p21) distribution was followed from infection in passage 1 to complete transformation. in fbs, increased expression ... | 1986 | 3019533 |
| molecular cloning of the temperature-sensitive 371 kirsten murine sarcoma virus and expression in escherichia coli of the mutant and wild-type viral kirsten ras p21 proteins. | rodent fibroblasts infected with the ts371 kirsten murine sarcoma virus (kimusv) are temperature sensitive for the maintenance of transformation because of the production of an abnormal p21 protein. we cloned the ts371 kimusv provirus from the genome of a conditionally transformed nonproducer cell line, ts371 kimusv nrk clone 5 (t. y. shih, m. o. weeks, h. a. young, and e. m. scolnick, j. virol. 31:546-556, 1979). the molecularly cloned virus had 1,000-fold lower transformed focus-forming activi ... | 1986 | 3022010 |
| suppression of tumor growth by senescence in virally transformed human fibroblasts. | normal human cells whether embryonic, neonatal, or adult are resistant to experimentally induced tumorigenesis in contrast to rodent or chicken cells. we showed previously that neither transformation with simian virus 40 dna nor transfection with human mutant hras dna immortalized fs-2 cells (diploid, neonatal human fibroblasts). further, tumorigenicity was not induced, despite expression of the respective transforming gene products tumor (t) antigen or p21. here we describe treatment of fs-2 an ... | 1986 | 3022300 |
| the effect of viral transformation on prostaglandin production depends on cell type. | the role of prostaglandins in cellular differentiation and transformation has been widely studied. we have found previously that prostaglandin e2 production was greatly diminished in dog kidney cells (mdck) after transformation by harvey murine sarcoma virus. in the present study, we have shown that viral transformation can have differing effects in the ability to modify the production of prostaglandin in cultured cells. for example, the prostaglandin e2 production in rat kidney cells (nrk) is d ... | 1986 | 3022469 |
| altered cellular functions in a pc-12 cell clone chronically infected with retrovirus. | we characterized retrovirus-induced changes in pc-12 cell function and neuronal differentiation. pc-12 cells were infected with a neurotropic retrovirus (temperature-sensitive moloney murine leukemia virus, mutant ba-1). we isolated a cell clone from this infected culture that displayed altered response to nerve growth factor; increased choline acetyltransferase activity; and decreased basal and nerve growth factor-stimulated acetylcholinesterase activity. in addition, kirsten murine sarcoma vir ... | 1986 | 3022728 |
| assignment of ras proto-oncogenes in chinese hamsters: implications for mammalian gene linkage conservation and neoplasia. | hras and kras are the cellular homologs of the oncogenic transforming genes found in the harvey strain of murine sarcoma virus and the kirsten murine sarcoma virus, respectively. phyla as diverse as insects, birds, and mammals possess distinct hras and kras sequences, suggesting that these genes are essential to metazoa. in this report, we used a clone panel of chinese hamster x mouse c11d somatic cell hybrids segregating hamster chromosomes to map those genes. southern filter hybridization anal ... | 1986 | 3022995 |
| expression of viral p21ras during acquisition of a transformed phenotype by rat adrenal cortex cells infected with kirsten murine sarcoma virus. | rat adrenal cortex cells infected with kirsten murine sarcoma virus acquire a transformed phenotype in a progressive fashion. the expression of the viral p21ras does not appear to correlate with the degree of transformation of the adrenocortical cells but rather is produced at similar levels as the culture becomes transformed. this indicates that the expression of an oncogenic form of p21ras is not of itself sufficient to completely transform rat adrenal cortex cells. | 1986 | 3023835 |
| 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 |
| abelson virus drives the differentiation of harvey virus-infected erythroid cells. | abelson murine leukemia virus (a-mulv) and harvey murine sarcoma virus (ha-msv) are retroviruses carrying unrelated onc genes. however, both of these viruses are capable of stimulating the growth and differentiation of erythroid precursor cells; the target cells for both appear at the same time during fetal development and follow a similar pattern throughout ontogeny. in addition, the colonies induced by each virus are morphologically similar and synthesize the adult form of hemoglobin. however, ... | 1986 | 3002634 |
| revertants of ha-musv-transformed mdck cells express reduced levels of p21 and possess a more normal phenotype. | four subclones of the originally cloned harvey murine sarcoma virus-transformed madin darby canine kidney (mdck) cells have been isolated. these subclones fall into two general classes. two subclones have a fibroblastic morphology, have lost the growth requirement for prostaglandin e1 (pge1), do not respond to glucagon or vasopressin, and, in general, appear transformed. two other subclones have epithelioid morphologies, are growth-stimulated by pge1, respond to vasopressin with an increase in i ... | 1986 | 3002821 |
| an endogenous mouse mammary tumor virus genome common in inbred mouse strains is located on chromosome 6. | we have examined ecori-restricted cellular dna from mouse-hamster somatic cell hybrids. results of this analysis show that the unit ii mouse mammary tumor virus proviral genome is located on mouse chromosome 6. restriction analysis of cellular dna from (c3h/ouj x czech ii) x czech ii backcross mice showed a strong linkage between unit ii and igk. the gene order of these markers on chromosome 6 relative to the raf and kirsten murine sarcoma virus ras-2 proto-oncogenes was established. | 1986 | 3003402 |
| monoclonal antibody detection of transformation associated protein (tap) in ts110 moloney murine sarcoma virus transformed 6m2 cells that are different from the mos gene product. | by the use of a highly specific monoclonal antibody (designated mc), we were able to detect three radiolabeled bands with molecular weights of 60,000, 63,000, and 66,000 daltons in the ts-110 moloney murine sarcoma virus mutant-transformed rat kidney cells known as 6m2. expression of transformation properties as well as these three bands in 6m2 cells was found to be temperature sensitive. therefore, mc detected factors that are apparently associated with the transformation of 6m2 cells. these fa ... | 1986 | 3004486 |
| homologous recognition of a promoter domain common to the msv ltr and the hsv tk gene. | we have partially purified, from rat liver, a nuclear protein fraction with sequence-specific affinity to a promoter domain shared by the herpesvirus tk gene and the moloney murine sarcoma virus ltr. for both promoters, the protein-binding domain occurs roughly 80 bp upstream of the mrna cap site and harbors the pentanucleotide sequence 5'-ccaat-3'. the msv ltr pentanucleotide occurs on the coding strand in an orientation pointing toward the retroviral transcription unit. the hsv tk pentanucleot ... | 1986 | 3004739 |
| oncogenic retrovirus from spontaneous murine osteomas. ii. molecular cloning and genomic characterization. | an n-ecotropic murine leukemia virus (oa mulv), originally isolated from spontaneous osteomas of strain 101 mice, was molecularly cloned. the virus induces osteomas, osteopetrosis, and malignant lymphomas in nmri mice. the cloned virus was analyzed by heteroduplex analysis, restriction enzyme mapping, and oligonucleotide mapping. the data show a very close relationship to the endogenous akv prototype virus with some differences in the gag and the env region. the nucleotide sequence of the u3 reg ... | 1986 | 3006346 |
| hydrocortisone promotes the neodifferentiation of kirsten murine sarcoma virus transformed human skin fibroblasts to adipose cells: relevance to oncogenic mechanisms. | 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) promotes the transformation/neodifferentiation of such preadipocytes into mature fat cells. the effects of hc on the expression of adipocyte-containing foci and on the total number of transformed foci present in kimsv-treated cultures appeared to be dose-dependent and was optimal at a concen ... | 1986 | 3007230 |
| an agent or agents produced by virus-transformed cells cause unregulated ruffling in untransformed cells. | knrk cells (a normal rat kidney [nrk] cell line transformed by kirsten murine sarcoma virus) in sparse culture exhibit a highly ruffled morphology, but the cause of this ruffling is unknown. in this study, we have demonstrated that the continuous, excess ruffling on knrk cells is caused by one or more soluble agents secreted by the knrk cells themselves. to do this study, an assay for ruffling responses in live cell cultures was defined, and its reproducibility was demonstrated. this assay permi ... | 1986 | 3007528 |
| cell-mediated co-action of transforming growth factors: incubation of type beta with normal rat kidney cells produces a soluble activity that prolongs the ruffling response to type alpha. | intense, continuous ruffling is a characteristic of many transformed cells, but untransformed cells ruffle intensely only briefly after exposure to growth factors. we reported previously that cells of a normal rat kidney (nrk) cell line transformed by kirsten murine sarcoma virus secrete their own ruffle-inducing agent(s) that cause sustained ruffling in either themselves or untransformed nrk cells. in the present study, we examined the roles of the transforming growth factors tgf-alpha and tgf- ... | 1986 | 3007529 |
| nucleotide sequence of exon i of the rat c-k-ras gene. | we have isolated a dna fragment containing exon i of rat cellular proto-oncogene of k-ras and sequenced the exon i. the obtained sequence was compared with that of the corresponding region in viral oncogene of kirsten strain of murine sarcoma virus (ki-msv). the results showed that the exon i sequences of cellular k-ras genes in rat and human cells could encode the same amino acid sequence, while the viral k-ras gene could code for two different amino acids corresponding to the 12th and 37th pos ... | 1986 | 3009041 |
| transcriptional "silencer" element in rat repetitive sequences associated with the rat insulin 1 gene locus. | the enhancer elements from either simian virus 40 or murine sarcoma virus activate the expression of a transfected rat insulin 1 (ri1) gene when placed within 2.0 kilobases or less of the ri1 gene cap site. inclusion of 4.0 kilobases of upstream ri1 sequence, however, results in a substantial reduction in the enhancer-dependent insulin gene expression. these observations suggested that a negative transcriptional regulatory element was present between 2.0 and 4.0 kilobases of the ri1 sequence. to ... | 1986 | 3010279 |
| retroviral mutants efficiently expressed in embryonal carcinoma cells. | the myeloproliferative sarcoma virus (mpsv) is a unique member of the moloney murine sarcoma virus family. due to mutations in the u3 region of its long terminal repeat, mpsv has an expanded host range that includes cells of the hematopoietic compartment. using a mpsv recombinant containing the gene for neomycin-resistance (neor-mpsv), we demonstrate that the host range of mpsv also includes undifferentiated f9 embryonal carcinoma cells. transfer of g418-resistance with neor-mpsv to f9 cells is ... | 1986 | 3010288 |
| dna polymorphisms indicate loss of heterozygosity for chromosome 11 of d98ah2 cells. | studies with cell hybrids of normal diploid cells fused with tumorigenic d98ah2 (d98) cells had implicated human chromosome 11 of a normal cell as carrying tumorigenicity suppressing information. the cervical carcinoma-derived d98 (hela) cells contain two copies of chromosome 11. in this study, analysis of restriction fragment length polymorphism of dna from d98 cells digested with one of nine restriction endonucleases and hybridized with five dna probes for highly polymorphic regions on the sho ... | 1986 | 3011364 |
| expression of the v-mos gene alters a mr 55,000 protein during acute infection by moloney murine sarcoma virus. | infection of the rat myoblast cell line, l6e9, with moloney murine sarcoma virus (mo-musv) clone 124, altered a cellular protein of mr 55,000 (p55) within 2 days of infection. the alteration of p55 was observed as a reduction in its steady-state level in cell extracts. the reduction of p55 correlated with the appearance of p37mos in infected cells. except for p55 and one other protein, no change was detected in the total protein pattern of infected cells compared to uninfected cells, as judged b ... | 1986 | 3012522 |
| antibodies against small nuclear ribonucleoproteins immunoprecipitate complexes containing ts110 moloney murine sarcoma virus genomic and messenger rnas. | small nuclear ribonucleoproteins (snrnps) are believed to play a role in processing premessenger rnas. in this study, snrnps were immunoprecipitated from extracts of cells infected with ts110 moloney murine sarcoma virus (ts110 momusv). both the unspliced 4.0 kb and the spliced 3.5-kb ts110 momusv specific rna species were found in the immunoprecipitates obtained with monoclonal antibody anti-sm and polyclonal anti-sm, anti-(u1) rnp and anti-la sera. although only a portion of the total ts110 rn ... | 1986 | 3012876 |
| glucocorticoid responsiveness of the transcriptional enhancer of moloney murine sarcoma virus. | the long terminal repeat of moloney murine sarcoma virus (momsv) contains an imperfect direct repeat that serves as a strong transcriptional enhancer. the strength of the momsv enhancer is strongly dependent on the presence of glucocorticoid hormone. mapping studies in combination with dnaase i footprinting experiments define the presence of glucocorticoid regulatory elements at the promoter-proximal ends of each enhancer repeat. these elements behave like inducible enhancers: their regulatory a ... | 1986 | 3013424 |
| efficient constitutive production of human ifn-gamma in chinese hamster ovary cells. | a human genomic dna segment of 5.6 kb containing the entire gene for immune interferon-gamma was fused through its 5'-untranslated region to the corresponding region of the simian virus 40 (sv40) t-antigen gene. the sv40 early promoter used contained a modified transcriptional enhancer element with a 93-bp repeat. supercoiled plasmid dna was used to transfect chinese hamster ovary (cho) cells, the selectable marker being a sv40-dihydrofolate gene construct. constitutive expression of the ifn-gam ... | 1986 | 3013545 |
| moloney murine sarcoma virus encoded p37mos expressed in yeast has protein kinase activity. | we describe the expression of the moloney murine sarcoma virus env-mos protein (p37mos) in yeast under the control of the yeast gal1 promoter. consistent with our previous results concerning the p37mos protein kinase made in virus infected mouse cells, p37mos produced in yeast possesses autophosphorylation activity in an immune complex kinase assay using anti-mos (37-35) serum. | 1986 | 3014729 |
| v-ras genes from harvey and balb murine sarcoma viruses can act as initiators of two-stage mouse skin carcinogenesis. | activated harvey murine sarcoma virus ras genes were introduced into epidermal cells in vivo by direct application of retroviruses to mouse skin. subsequent treatment with the tumor promoter 12-o-tetradecanoyl-phorbol-13-acetate (tpa) induced benign papillomas, some of which progressed to invasive carcinomas. initiation with virus was irreversible for at least 4 months, since tpa treatment after this latency period produced papillomas within 4 weeks. analysis of viral integration sites showed th ... | 1986 | 3015415 |
| keratin expression of both chemically and virally transformed human epidermal keratinocytes during the process of neoplastic conversion. | human epidermal cells, despite being 'immortalized' or 'transformed' by combinations of either oncogenic virus (sv40, adenovirus 12 or kirsten murine sarcoma virus) or chemical carcinogen (n-methyl-n'-nitro-n-nitrosoguanidine or 4-nitroquinoline-1-oxide) exhibited similar keratins (although quantitatively reduced) to that of control cells when grown in vitro. however, athymic nude mouse tumors derived from such cells exhibited suppression of the 52, 56 and 58 kd (basic type ii) keratins and a pr ... | 1986 | 2417737 |
| class ii histocompatibility antigen expression in human melanocytes transformed by harvey murine sarcoma virus (ha-msv) and kirsten msv retroviruses. | human melanocytes infected with ki-msv or ha-msv, but not amphotropic mulv, undergo a series of transformation-related changes that are characteristic of malignant melanoma. these are (a) expression of ia antigens, in particular dp, dq, and dr class ii histocompatibility gene products, (b) a transformed morphology and ability to grow in soft agar, and (c) a 5-10-fold increase in the cell surface expression of gd3 ganglioside. however, other characteristics of melanoma, such as independence from ... | 1986 | 2430046 |
| an activated harvey ras oncogene produces benign tumours on mouse epidermal tissue. | studies of the mutagenic action required for specific chemicals to produce benign or malignant tumours suggest that in mouse skin at least two genetic events occur before carcinoma formation. the isolation of an activated form of the c-rash gene from skin papillomas has provided evidence that this gene may be a target for the first mutation, which could constitute the initiating mutation in skin carcinogenesis. in vitro studies indicate that the v-rash gene of harvey murine sarcoma virus (ha-msv ... | 1986 | 2430189 |
| a syngeneic monoclonal antibody to murine meth-a sarcoma (hepss-1) recognizes heparan sulfate glycosaminoglycan (hs-gag): cell density and transformation dependent alteration in cell surface hs-gag defined by hepss-1. | we have isolated a syngeneic monoclonal antibody (hepss-1) reactive to a murine methylcholanthrene-induced fibrosarcoma, meth-a. hepss-1 also bound to a wide variety of established and fresh normal cells derived from not only mice but also other species such as human, monkey, rat, hamster, and chicken. immunoprecipitation of surface iodinated meth-a cell extract with hepss-1, as well as sepharose 4b gel chromatography of meth-a cell extract and detection of antigens recognized by hepss-1 by a sa ... | 1986 | 2431047 |
| differential transformation of c3h10t1/2 cells by v-mos: sequential expression of transformation parameters. | extremely small quantities of the product of the transforming gene v-mos of moloney murine sarcoma virus are able to efficiently transform cells. recent data indicate the existence of a threshold level for v-mos transformation of nih3t3 cells. using mouse mammary tumor virus long terminal repeat sequences or hybrid promoters consisting of mouse mammary tumor virus and moloney murine sarcoma virus long terminal repeat elements to express v-mos in c3h10t1/2 cells, we established cell lines represe ... | 1985 | 3016522 |
| enhancer-dependent expression of the rat preproinsulin gene in bovine papillomavirus type 1 vectors. | the effect of position in a bovine papillomavirus type 1 (bpv-1) vector on foreign gene expression was assessed with the rat preproinsulin (ri1) gene. the ri1 gene was inserted at each of the bpv-1/pml2d junctions in either transcriptional orientation in derivatives of the pdbpv-1(142-6) vector which consists of the bamhi linear genome of bpv-1 dna cloned into pml2d. transformed lines of c127 cells were established and assayed for ri1 gene expression. cells containing the ri1 gene at the 3' end ... | 1985 | 3018523 |
| delineation of transcriptional control signals within the moloney murine sarcoma virus long terminal repeat. | we identified three distinct elements within the moloney murine sarcoma virus long terminal repeat that control transcription. the phenotypes of unidirectional deletion mutants of the long terminal repeat were assayed in microinjected frog oocytes and in transfected mouse fibroblasts. steady-state levels of rna bearing the same 5' terminus as the authentic moloney murine sarcoma viral transcripts were measured by primer extension in assays that included a pseudo-wild-type internal reference. mut ... | 1985 | 3018539 |
| alternate utilization of two regulatory domains within the moloney murine sarcoma virus long terminal repeat. | the moloney murine sarcoma virus long terminal repeat (ltr) harbors two distinct positive activators of transcription, namely, a distal signal and an enhancer. in this report we demonstrate that infection by herpes simplex virus (hsv) can markedly affect the utilization of these two moloney murine sarcoma virus transcription signals. we investigated the hsv-mediated trans-acting effects with two goals in mind: first, to gain insight into ltr function, and second, to probe the mechanisms used by ... | 1985 | 3018540 |
| 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 |
| 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 |
| analysis of the cellular proto-oncogene mht/raf: relationship to the 5' sequences of v-mht in avian carcinoma virus mh2 and v-raf in murine sarcoma virus 3611. | the avian carcinoma virus mh2 contains a hybrid gene delta gag-mht with a contiguous open reading frame of 2682 base pairs as well as v-myc and avian helper virus-related sequences. delta gag is a partial retroviral core protein gene while v-mht and v-myc are cell-drived sequences. the v-mht sequence can be divided into two regions: the v-raf-related region at its 3' end contains 969 nucleotides which are 94% related as amino acid sequence to the onc-specific v-raf sequence of murine sarcoma vir ... | 1985 | 3002017 |
| 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 |