| dependence of initiation of an innocent bystander cytotoxicity reaction on the association of viral antigens and tumor cell membranes in mice. | in chemically induced mouse mammary tumors in balb/c mice, no murine mammary tumor virus (mumtv) antigens could be detected in the tumor cell membranes. in contrast, in mammary tumors of spontaneous appearance in balb/cfc3h mice neonatally infected with mumtv, viral antigens could be detected by immunofluorescence. specific activation of immune spleen lymphocytes in vitro by homologous tumor cell membrane preparations resulted in an innocent bystander cytotoxicity reaction in balb/c mice bearing ... | 1986 | 2871214 |
| a preferred region for integration of friend murine leukemia virus in hematopoietic neoplasms is closely linked to the int-2 oncogene. | gene mapping experiments show that fis-1, a preferred integration region for friend murine leukemia virus in hematopoietic neoplasms, is extremely closely linked to int-2, a preferred integration region for mouse mammary tumor virus in mammary carcinomas. studies at the rna and dna level prove that these loci are distinct. | 1986 | 2878090 |
| genetic mapping of prm-1, igl-1, smst, mtv-6, sod-1, and ets-2 and localization of the down syndrome region on mouse chromosome 16. | molecular probes were used as markers in the backcross (czech ii x balb/cpt) x czech ii to determine the positions of six genes on mouse chromosome 16 (mmu 16). the order of the genes mapped is (centromere), protamine-1 (prm-1), immunoglobulin lambda 1 light chain (igl-1), preprosomatostatin (smst), an endogenous mouse mammary tumor virus locus (mtv-6), and two more distal sequences, superoxide dismutase, cytoplasmic form (sod-1), and the proto-oncogene sequence ets-2. the largest recombination ... | 1987 | 2882955 |
| stimulation of expression of the human endogenous retrovirus genome by female steroid hormones in human breast cancer cell line t47d. | expression of the human endogenous retrovirus genome herv-k, homologous to mouse mammary tumor virus, was investigated in cultured human tumor cells. in several cell lines, the herv-k genome was expressed as an 8.8-kilobase poly(a)+ rna which appeared to be a full-size transcript of this genome. in the human breast cancer cell line t47d, stimulation of herv-k genome expression by progesterone was observed after estradiol treatment. | 1987 | 2883329 |
| retroviral heterogeneity in mouse lymphomas. | provirus modifications which can occur in tumors may lead to tumor antigenic variants. to investigate this possibility we compared the restriction fragment length patterns of mouse mammary tumor virus (mmtv), murine leukemia virus and xenotropic and mink cell-focus inducing (mcf)-related sequences, using southern blot analysis, in a panel of balb/c and c57bl/6 lymphomas, some of which were known to express novel histocompatibility (h) antigens. the results indicate differences in amplification a ... | 1988 | 2896330 |
| single-step induction of mammary adenocarcinoma in transgenic mice bearing the activated c-neu oncogene. | we have used transgenic mice that carry an activated c-neu oncogene driven by a mouse mammary tumor virus (mmtv) promoter to assess the stepwise progression of carcinogenesis in mammary epithelium. unlike the stochastic occurrence of solitary mammary tumors in transgenic mice bearing the mmtv/c-myc or the mmtv/v-ha-ras oncogenes, transgenic mice uniformly expressing the mmtv/c-neu gene develop mammary adenocarcinomas that involve the entire epithelium in each gland. because these tumors arise sy ... | 1988 | 2898299 |
| unlinked regulation of the sensitivity of primary glucocorticoid-inducible responses in mouse mammary tumor virus infected fu5-5 rat hepatoma cells. | the enzyme tyrosine aminotransferase (tat) is induced by unusually low concentrations of glucocorticoids in fu5-5 cells. we have isolated clones of fu5-5 cells infected with mouse mammary tumor virus (mmtv) in order to simultaneously compare the glucocorticoid regulation of the host cell gene, tat, with that of another primary inducible gene, mmtv. in the two clones that were examined in detail, mmtv rna induction occurred at 4- to 11-fold higher concentrations of dexamethasone than those needed ... | 1988 | 2906113 |
| mmtv as a model for gene expression in mammary tissue. | | 1988 | 2908656 |
| the activation of cellular oncogenes by proviral insertion in murine mammary cancer. | | 1988 | 2908657 |
| steroid hormone regulation of cultured breast cancer cells. | | 1988 | 2908658 |
| binding of hormone accelerates the kinetics of glucocorticoid and progesterone receptor binding to dna. | steroid hormone receptors induce genes by virtue of their interaction with dna regulatory sequences. the hormonal response of a particular gene in vivo correlates with binding of the hormone to the receptor and supposedly reflects the degree of occupancy of the corresponding dna regulatory sequences. however, in vitro the steroid-free glucocorticoid and progesterone receptors bind specifically to the regulatory sequences of mouse mammary tumor virus, thus raising questions on the role of the hor ... | 1989 | 2919163 |
| mitogenic activity of the adenovirus type 12 e1a gene induced by hormones in rat cells. | several lines of rat 3y1 cells in which expression of the adenovirus type 12 e1a gene can be regulated by dexamethasone were established by introduction of recombinant vector dna containing the adenovirus type 12 e1a gene placed downstream of the hormone-inducible promoter of mouse mammary tumor virus. these cell lines (gma cells) produced low basal levels of the e1a transcripts and proteins in normal medium and much higher levels upon addition of dexamethasone to the medium. when dexamethasone ... | 1986 | 2936902 |
| tumor-specific idiotype vaccines. ii. analysis of the tumor-related network response induced by the tumor and by internal image antigens (ab2 beta). | in this study the tumor-specific immuneresponse induced by irradiated tumor cells (l1210/gzl) and by anti-idiotype antibodies was analyzed. the anti-idiotype antibodies (ab2) were made against the paratope of a monoclonal antitumor antibody (11c1) that recognizes a tumor-associated antigen which cross-reacts with the mouse mammary tumor virus-encoded envelope glycoprotein 52. two ab2, 2f10 and 3a4, induced idiotypes expressed by the monoclonal antitumor antibodies 11c1 and 2b2. cytotoxic t cells ... | 1987 | 2953815 |
| induction of cell cycle progression by adenovirus e1a gene 13s- and 12s-mrna products in quiescent rat cells. | rat 3y1 cell lines that express either adenovirus type 12 e1a 13s mrna or 12s mrna in response to dexamethasone treatment were established by introduction of recombinant vector dna containing the e1a 13s- or 12s-mrna cdna placed downstream of the hormone-inducible promoter of mouse mammary tumor virus. these cell lines were growth arrested, and the induction of cell cycle progression was analyzed by flow cytometry after switch on of the cdna by the addition of dexamethasone. the results indicate ... | 1987 | 2960886 |
| b cell subsets in spleens of balb/c mice: identification and isolation of mmtv-expressing and mmtv-responding subpopulations. | the dna of balb/c mice contains two genomic- and one subgenomic-size mmtv proviruses that appear to be preferentially expressed in their spleen cells, although intact mmtv virions cannot be detected in the tissues of these mice. this retrovirus antigen expression is restricted to a subpopulation of b lymphocytes, as determined by double label immunofluorescence studies. nylon-adherent, sig-positive spleen lymphocytes from balb/c mice are capable of being stimulated by purified mmtv in lymphocyte ... | 1985 | 2981095 |
| the involvement of a type-b retrovirus in the induction of thymic lymphomas. | a highly leukemogenic virus (dmba-lv) (in vivo leukemogenic titer 1-5 x 10(6) iu/ml, and 35-40 days to thymic lymphoma detection) is produced by a chemical carcinogen-induced transplanted thymic lymphoma. the virus preparation is a mixture of a type-b retrovirus highly related to exogenous type-b retroviral isolates and a biologically defective type-c retrovirus. the dna of dmba-lv-induced-tumors contains new type-b proviruses but no additional type-c proviruses could be detected. the leukemogen ... | 1985 | 2981451 |
| immunologic studies with mouse mammary tumor viruses: comparative studies with spontaneous mammary tumor cell vaccines from five inbred mouse strains. | vaccines were prepared from cells of primary spontaneous mammary tumors (mt) of riii/imr, gr/imr, c3h/imr, a/imr, and c3hfc57bl/imr mice. each vaccine was used to immunize "murine mammary tumor virus (mumtv)-free" balb/c/imr and c57bl/imr mice before challenge with infectious riii-mumtv, gr-mumtv, c3h-mumtv, and a-mumtv. riii-mt and c3h-mt cells protected mice against tumorigenesis by all four mumtv's; gr-mt cells protected against all but the riii-mumtv challenge; a-mt cells were ineffective ag ... | 1985 | 2982052 |
| natural infection of swiss mice with mouse mammary tumor virus (mmtv): viral expression in milk and transmission of infection. | quantitative determinations of gp52, the main envelope glycoprotein, and p28, the main core protein, of mmtv, have been performed in about 1000 individual samples of milk of breeding females from our colony of mmtv-infected swiss mice, a line characterized by a moderate incidence of mammary tumors. a computer analysis of the results showed: 1-- an important individual variation, ranging from 0 to 120 micrograms per ml of milk for p28, and from 0 to 320 micrograms per ml of milk for gp52; 2-- a v ... | 1985 | 2982354 |
| autochthonous murine tumors: effects of viral or ultraviolet induction, immunogenicity and transplantation on intratumoral macrophages and systemic inflammatory responses. | macrophage tumoricidal activity requires a constant influx of macrophages but many transplanted cancers inhibit macrophage inflammatory responses. in this paper we address the issue of whether or not autochthonous tumors induced by either mammary tumor virus (mtv) in c3h/he mice or ultraviolet (u.v.) radiation in c3h/he or balb/c mice also depress macrophage responses. anti-inflammatory activity was not observed either prior to or during growth of these autochthonous tumors. rather, the opposite ... | 1985 | 2982619 |
| hormonal induction of uterine sarcomas in gr mice not dependent on mammary tumor virus genes or uterine trauma. | | 1985 | 2982620 |
| interaction of the heterozygous nude gene with the asplenia trait in mammary tumorigenesis. | the balb/c mouse strain has been shown to contain endogenous mouse mammary tumor virus (mmtv) proviral sequences. however, no exogenous mmtv particles have been detected in their tissues. female balb/c mice from our colonies exhibit a very low incidence of spontaneous mammary tumors (smt); less than 1% at up to 20 mo of age. immunodeficient balb/c mice heterozygous for the nude gene (nu/+, +/+), for the dominant hemimelia gene associated with asplenia (+/+, dh/+), or for both traits (nu/+, dh/+) ... | 1985 | 2982992 |
| characterization of an endogenous retrovirus-repetitive dna chimera in the mouse genome. | we found that an endogenous mouse mammary tumor provirus, gr-mtv-8, is embedded within a member of the bam hi family of long interspersed repetitive mouse dnas. gr-mtv-8 appears to be transcriptionally silent at its normal chromosomal position in the mouse genome. the provirus is transcriptionally active, however, when cloned and transfected into mouse cells (kennedy et al., nature (london) 295:622-624, 1982). we propose that the transcriptional inactivity of gr-mtv-8 in situ is due to an inhibi ... | 1985 | 2983106 |
| generation of glucocorticoid-responsive moloney murine leukemia virus by insertion of regulatory sequences from murine mammary tumor virus into the long terminal repeat. | the glucocorticoid-regulatory sequences from the murine mammary tumor virus long terminal repeat (mmtv ltr) were introduced into the ltr of moloney murine leukemia virus (m-mulv) by recombinant dna techniques. the site of insertion was in the m-mulv ltr u3 region at -150 base pairs with respect to the rna cap site. infectious m-mulvs carrying the altered ltrs (mo + mmtv m-mulvs) were recovered by transfection of proviral clones into nih-3t3 cells. the mo + mmtv m-mulvs were hormonally responsive ... | 1985 | 2983110 |
| comparative studies of purified subviral component vaccines and formalin-treated mammary tumor viruses from four inbred strains of mice. | formalin-treated virus vaccines were prepared from purified murine mammary tumor viruses (mumtv) from 4 inbred strains of mice: riii/imr, gr/imr, c3h/imr, and a/imr. in addition, subviral components were isolated from these 4 strains and purified to homogeneity. the inactivated viruses, their major envelope glycoproteins (gp50-gp55), and their major internal core protein (p28) were emulsified in complete freund's adjuvant and used as vaccines for prevention of mammary tumors in mice. all 4 forma ... | 1985 | 2983136 |
| glucocorticoid and progesterone receptors bind to the same sites in two hormonally regulated promoters. | the glucocorticoid receptor of rat liver recognizes nucleotide sequences near the promoter of mouse mammary tumour virus (mmtv) required for hormonal induction in gene transfer experiments. similar nucleotide sequences have been found in the human metallothionein gene iia and in the chicken lysozyme gene, the later induced also by oestrogen, progesterone and androgens. in microinjection experiments, deletion of only 44 base pairs (bp) of the lysozyme promoter (from -208 to -164) results in coord ... | 1985 | 2983219 |
| the first intron of the human growth hormone gene contains a binding site for glucocorticoid receptor. | glucocorticoid receptor (gcr) protein stimulates transcription from a variety of cellular genes. we show here that gcr partially purified from rat liver binds specifically to a site within the first intron of the human growth hormone (hgh) gene, approximately 100 base pairs downstream from the start of hgh transcription. gcr binding is selectively inhibited by methylation of two short, symmetrically arranged clusters of guanine residues within this site. a cloned synthetic 24-base-pair deoxyolig ... | 1985 | 2983311 |
| hormonal response region in the mouse mammary tumor virus long terminal repeat can be dissociated from the proviral promoter and has enhancer properties. | the proviral dna of mouse mammary tumor virus (mmtv) contains a regulatory region closely associated with its promoter, which subjects transcription to the control of glucocorticoid hormones. delimitation analysis of a chimeric mmtv long terminal repeat-thymidine kinase gene (ltr-tk) has shown that the hormonal regulation sequence is confined to 202 nucleotides preceding the ltr-specific rna initiation site. a second rna initiation site (tk-specific mrna) placed close to the regulatory mmtv sequ ... | 1985 | 2983325 |
| characterization of a protein, released by the t47d cell line, immunologically related to the major envelope protein of mouse mammary tumor virus. | the t47d human mammary adenocarcinoma cell line in vitro releases viral particles as well as soluble proteins. both fractions were shown to contain antigens that immunologically crossreact with the major glycoprotein (gp52) of mouse mammary tumor virus. the crossreacting antigens are located on polypeptides with apparent molecular weights of about 68,000 and 60,000. the larger one is present in viral particles whereas both are found in the soluble fraction. both proteins are glycosylated. the hu ... | 1985 | 2983349 |
| [molecular genetic bases of the oncogenic action of the mouse mammary tumor virus]. | processes associated with the neoplastic action of the mammary carcinoma virus on cells of the mammary gland myoepithelium are reviewed. possible mechanisms of this action, stages of neoplastic process, at which the oncogenic mmtv potential is realized, and problems of virus and hormone cocarcinogenic action are discussed. | 1985 | 2983972 |
| coordinate inhibition of plasminogen activator and tumor growth by hydrocortisone in mouse mammary carcinoma. | a body of evidence has suggested that hormones which modulate plasminogen activator production by cultured tumor explants in vitro may have a qualitatively comparable effect on the growth of the same tumors in vivo. as a test of this correlation and to explore its potential for predicting the in vivo response of tumors to hormones, we have studied here the effect of hydrocortisone on the growth of primary and first generation transplants of mouse mammary tumor virus-determined mammary tumors in ... | 1985 | 2985248 |
| transgenic mice. | | 1985 | 2985274 |
| tubular structures in s49 mouse lymphoma are regulated through in vivo host-cell interaction and in vitro interferon treatment. | malignant s49 mouse lymphoma cells that grow in suspension culture demonstrate in their cytoplasm characteristic tubular structures. these structures also appear in immunogenic, substrate-adherent variants of s49 cells that grow in culture. upon transfer of both cell types into nude mice, the tubular structures of the adherent variants (and not the suspension-growing cells) undergo a profound alteration whereby their tubular components disappear and clusters of viruslike particles appear. these ... | 1985 | 2985621 |
| molecular cloning, characterization, and genetic mapping of an endogenous murine mammary tumor virus proviral unit i of c3h/he mice. | we have cloned and characterized a novel endogenous murine mammary tumor virus proviral unit of the c3h/he strain of mice. the cloned proviral unit is 16 kilobase pairs (kbp) in size and is composed of a 5.6-kbp 5' ecori segment of an endogenous provirus with 10.4-kbp flanking cellular sequences. a comparison of the restriction map of the cloned proviral dna with that of an endogenous provirus of the gr strain of mice has revealed minor differences in restriction sites on the two proviruses. the ... | 1985 | 2985797 |
| sequence organization and molecular cloning of mouse mammary tumor virus dna endogenous to c57bl/6 mice. | the sequence organization of mouse mammary tumor virus dna endogenous to the c57bl/6 inbred mouse strain was characterized by southern blot analysis, utilizing probes specific for particular regions of the mouse mammary tumor virus provirus and by molecular cloning of endogenous mouse mammary tumor virus dna. the genome of c57bl/6 mice contains three apparently intact, endogenous proviral units; two of these units comprise the mtv-8 (unit ii) and mtv-9 (unit iii) genetic loci that are also prese ... | 1985 | 2985815 |
| rearrangements in the long terminal repeat of extra mouse mammary tumor proviruses in t-cell leukemias of mouse strain gr result in a novel enhancer-like structure. | male gr mice develop t-cell leukemia at low frequency late in life. these leukemia cells invariably contain large amounts of mouse mammary tumor virus (mmtv) rna and mmtv proteins and have extra mmtv proviruses integrated in their dna. we show here that the extra mmtv proviruses are all derived from the endogenous mmtv provirus associated with the mtv-2 locus and that the t-cell leukemias are clonal with respect to the acquired mmtv proviruses. the extra mmtv proviruses in six transplantable t-c ... | 1985 | 2985971 |
| subline divergence within l.c. strong's c3h and cba inbred mouse strains. a review. | | 1985 | 2987113 |
| mouse mammary tumour virus: a proviral gene contributes to the understanding of eukaryotic gene expression and mammary tumorigenesis. | | 1985 | 2987402 |
| analysis of tissue-specific methylation patterns of mouse mammary tumor virus dna by two-dimensional southern blotting. | we used a two-dimensional southern blotting procedure to analyze the tissue-specific methylation patterns of the five endogenous mouse mammary tumor viruses in the gr/a mouse strain. our findings suggest that in certain tissues (brain, kidney, and liver) all proviruses are extensively methylated. in other tissues (spleen, placenta, and testes) all proviruses are hypomethylated to some degree. in these tissues individual proviruses display both quantitative and qualitative differences in methylat ... | 1985 | 2987526 |
| alterations in chromatin structure associated with glucocorticoid-induced expression of endogenous mouse mammary tumor virus genes. | alterations in the chromatin structure of endogenous mouse mammary tumor virus genes accompany glucocorticoid induction of viral rna synthesis in the c57bl/6 t lymphoma cell line t1m1. these alterations are defined by the appearance of sites of dnase i hypersensitivity within proviral dna in isolated nuclei, as well as by changes in the moderate nuclease sensitivity of entire proviral transcription units. induced hypersensitive sites, termed type i, appear with a time course comparable to that r ... | 1985 | 2987676 |
| the tggca protein binds to the mmtv-ltr, the adenovirus origin of replication, and the bk virus enhancer. | tggca-binding proteins are nuclear proteins with high affinity for double-stranded dna homologous to the prototype recognition sequence 5'ytggcannntgccar 3'. their ubiquitous tissue distribution in higher vertebrates characterizes them as a class of highly conserved proteins which may exert a basic function. to obtain clues to this function, specific binding sites were mapped on three viral genomes. recognition sites were identified in the enhancer region of the bk virus, in the ltr of the mouse ... | 1985 | 2987840 |
| mammary tumorigenesis in c3hf/ki mice: examination of germinal mouse mammary tumor viruses and the int-1 and int-2 putative proto-oncogenes. | the organization and expression of endogenous mouse mammary tumor virus (mmtv) proviruses in normal and neoplastic c3hf/ki tissues were examined. mmtv-containing ecori, hindiii, bamhi and psti restriction fragments of c3hf/ki dna were identical to those of c3h/stwi dna. the full-length endogenous mmtv units ia (mtv-7), ii (mtv-8), iii (mtv-9) and iv (mtv-10), in addition to the subgenomic endogenous mmtv units i (mtv-6) and ix (mtv-14), were germinally transmitted in c3hf/ki dna. the previously ... | 1985 | 2988229 |
| steroid hormone regulation of gene expression. | | 1985 | 2988423 |
| is the aids virus recombinant? | | 1985 | 2989705 |
| proteolytic release of glycopeptides from glycoproteins transferred to nitrocellulose following gel electrophoresis. | to determine whether glycopeptides could be released from glycoproteins bound to nitrocellulose, the glycoproteins of murine mammary tumor virus (mumtv) were radiolabeled by the periodate oxidation/tritiated sodium borohydride reduction technique and separated by gel electrophoresis followed by diffusion transfer. pronase digestion of nitrocellulose filter strips containing labeled glycoproteins (gp55 or gp34) revealed a rapid release of glycopeptides, i.e., approximately total release within 4 ... | 1985 | 2990256 |
| [expression of antigens immunologically related to the antigens of the mouse mammary tumor virus in the tissue of human breast tumors]. | indirect radioimmunoblotting on nitrocellulose filters and elisa on polystyrene plates were employed to test the specimens of the normal and tumor tissue of the mammary gland for antigens which cross react with antigens of structural proteins of mouse mammary gland carcinoma virus. the antigens were detected in 9 tumor specimens out of 25 under testing and in 1 out of 15 specimens of the normal tissue. such antigens failed to be detected in fibroadenoma or tumors of other sites. | 1985 | 2990606 |
| horizontal transmission of the mouse mammary tumor virus in cage mates of the same and opposite sex of low and high mammary cancer strain mice. | horizontal transmission of mouse mammary tumor virus (mtv) was investigated in cage mates of the same and opposite sex of low (balb/c) and high mammary cancer strains (dd/tbr, shn and gr). by mtvp27 and mtvgp52 radioimmunoassay, mtv antigen expression was found in the salivary glands, mammary glands and secondary male genital organs of the mtv-free balb/c strain. infectivity and oncogenicity were also found in ddf or balb/c mice by inoculating extracts of salivary gland and/or seminal vesicle in ... | 1985 | 2990973 |
| proviral unit ii of endogenous mouse mammary tumour virus is selectively amplified and expressed in c57b1/10 mammary tumours induced by non-viral carcinogens. | restriction enzyme analysis and molecular hybridization assay of dna isolated from c57b1/10 mammary adenocarcinomas induced by a combination of dimethylbenzanthracene, oestrogen, and prolactin, revealed the presence of four extra copies of endogenous mouse mammary tumour virus (mmtv). psti restriction pattern of the amplified proviral sequences indicated their identity with the proviral unit ii of endogenous mmtv. the amplified proviruses are hypomethylated and expressed in a hormone-dependent f ... | 1985 | 2991294 |
| nucleotide sequence of the syrian hamster intracisternal a-particle gene: close evolutionary relationship of type a particle gene to types b and d oncovirus genes. | we determined the complete nucleotide sequence of the intracisternal a-particle gene, iap-h18, cloned from the normal syrian hamster liver dna. iap-h18 was 7,951 base pairs in length with two identical long terminal repeats of 376 base pairs at both ends. on the coding strand, imperfect open reading frames corresponding to gag and pol of the retrovirus genome were observed, whereas many stop codons were present in the region corresponding to env. the putative h18 gag gene (809 amino acids) had a ... | 1985 | 2991563 |
| peripheral neuropathies, hepatocellular carcinomas and islet cell adenomas in transgenic mice. | the ability to introduce foreign dna into the genome of mice offers unique opportunities to produce new models of disease process. recent experiments have shown that integration and expression of simian virus 40 (sv40) t antigen genes and the murine mammary tumour virus (mmtv)-myc genes in transgenic mice can lead to the development of neoplasia in a remarkably tissue-specific manner. in the case of sv40-bearing mice, tumours consistently develop in the choroid plexus. in the accompanying paper, ... | 1985 | 2991772 |
| molecular cloning of integrated caprine arthritis-encephalitis virus. | a full-length dna clone of the exogenous retrovirus, caprine arthritis-encephalitis virus (caev), was isolated from high molecular weight dna of caev-infected himalayan tahr ovary cells. although other restriction maps of caev have been published, this is the first time that the proviral dna has been cloned. the restriction enzyme map of the clone was determined and found to be identical to that of unintegrated linear caev dna except for the presence of cellular flanking sequences. these finding ... | 1985 | 2992157 |
| modulation of gene expression through dna-binding proteins: is there a regulatory code? | | 1985 | 2993112 |
| glucocorticoid regulation of mouse mammary tumor virus sequences in transgenic mice. | we have introduced a chimeric plasmid, pltr2tk, containing the mouse mammary tumor virus (mtv) long terminal repeat (ltr) linked to the herpes simplex virus type 1 thymidine kinase gene into the mouse germ line by microinjection. in one mouse line, the thymidine kinase gene is appropriately expressed in the lactating mammary glands of heterozygous females; expression also occurs in the ovaries of these mice. in heterozygous males of this line, and in a male derived from another microinjection, t ... | 1985 | 2994051 |
| estradiol 16 alpha-hydroxylation in the mouse correlates with mammary tumor incidence and presence of murine mammary tumor virus: a possible model for the hormonal etiology of breast cancer in humans. | in this report, we describe our findings on the relationship between estradiol 16 alpha-hydroxylation and mammary tumor incidence. a close correlation between the two has been demonstrated with 16-hydroxylation being elevated in strains with a high incidence of tumors, such as riii and c3h, and low in strains with a low incidence of cancer, such as c57bl. the extent of reaction is highly reproducible and unaffected by age or presence of overt mammary tumors. studies on the inheritance of estradi ... | 1985 | 2994069 |
| review of the effects of stress on cancer in laboratory animals: importance of time of stress application and type of tumor. | | 1985 | 2994138 |
| retroviruses as chromosomal genes in the mouse. | | 1985 | 2994403 |
| genetic differences in balb/c sublines. | | 1985 | 2994956 |
| [human breast cancer markers]. | the review contains data concerning breast cancer markers used now in clinical oncology and potential breast cancer markers. their origin, metabolism, detection methods, potentialities of application for tumour diagnosis, determination of therapy efficiency and prognosis are discussed. | 1985 | 2994992 |
| events in glucocorticoid hormone action. a correlation of histone h1 variant pattern changes, hormone binding to cell nuclei, and induction of mouse mammary tumor virus rna. | to approach experimentally changes of chromatin structure introduced by glucocorticoids, the histone h1 compositions of hormone-treated and non-treated mouse mammary tumor cells of the gr line [ringold, g., lasfargues, e. y., bishop, j. m. and varmus, h. e. (1975) virology 65, 135-147] were compared. to define the biologically important hormone concentration range, the cells were exposed to different concentrations of triamcinolone, a synthetic glucocorticoid. the induction of mouse mammary tumo ... | 1985 | 2995030 |
| cellular genes in the mouse regulate in trans the expression of endogenous mouse mammary tumor viruses. | the transcriptional activities of the eleven mouse mammary tumor virus (mmtv) proviruses endogenous to two sets of recombinant inbred (ri) mouse strains, bxd and bxh, were characterized. comparison of the levels of virus-specific rna quantitated in each strain showed no direct relationship between the presence of a particular endogenous provirus or with increasing numbers of proviruses. association of specific genetic markers with the level of mmtv-specific rna was examined by using multiple reg ... | 1985 | 2996982 |
| attenuation of exogenous murine mammary tumor virus virulence in the c3h/hej mouse substrain bearing the lps mutation. | a major change in mammary tumor incidence (mti) and latency has occurred in the c3h/hej mouse substrain maintained at the jackson laboratory. the average time required for 50% of the c3h/hej mice to develop a mammary tumor changed from 40 weeks of age to the current 61 weeks of age. this 61-week median mti in the c3h/hej substrain is significantly different from the less than 40-week median mti seen in other c3h substrains infected with an exogenous milk-transmitted murine mammary tumor virus (m ... | 1985 | 2997536 |
| an inherited limb deformity created by insertional mutagenesis in a transgenic mouse. | we have created an insertional mutation that leads to a severe defect in the pattern of limb formation in the developing mouse. the novel recessive mutation is phenotypically identical and non-complementary to two previously encountered limb deformity mutations, and is closely linked to a dominant mutation that gives rise to a related limb dysmorphism. the inserted element thus provides a molecular genetic link with the control of pattern formation in the mammalian embryo. | 1985 | 2997621 |
| characterization and chromosomal distribution of endogenous mouse mammary tumor viruses of european mouse strains sts/a and gr/a. | the endogenous mouse mammary tumor virus (mmtv) proviral copies in two genetically dissimilar mouse strains, sts/a, a european mouse strain, and balb/c, were characterized. sts/a carries the same four mmtv proviral copies as gr.mtv-2-; these strains share also most of the isoenzyme markers and are therefore highly related. cellular dna of gr.mtv-2- contains a partial mmtv provirus that is not present in sts/a. gr.mtv-2- is derived from gr; they differ in the locus mtv-2 that contains one mmtv pr ... | 1985 | 2997987 |
| identification and characterization of a mouse mammary tumor virus protein uniquely expressed on the surface of balb/cv mammary tumor cells. | a unique subline of balb/c mice, designated balb/cv, exhibits an intermediate mammary tumor incidence (47%) and harbors a distinct milk-transmitted mouse mammary tumor virus (mmtv). the balb/cv subline was used to study the molecular basis of potential virus-host interactions involving cell surface-expressed mmtv proteins. cell surface iodination identified virus-specific proteins expressed on balb/cv primary mammary tumor cells grown in culture. in contrast to (c3h)mmtv-producing cell lines whi ... | 1985 | 2997998 |
| production of mouse mammary tumor virus upon transfection of a recombinant proviral dna into cultured cells. | we have investigated the intracellular proteins synthesized in rat xc and feline kidney cells transfected with endogenous mouse mammary tumor virus (mmtv) proviral dna. the endogenous provirus gr40, associated with the mtv-8 locus, directs the synthesis of gag proteins indistinguishable from those found in mmtv-infected cells. the env precursor pr73env and the mature gp52 proteins could not be detected in these cells. instead an env-related protein of 68k is synthesized. in contrast to this endo ... | 1985 | 2998037 |
| mouse mammary tumor virus gene expression regulated in trans by lps locus. | expression of mouse mammary tumor virus (mmtv) in the lactating mammary glands of uninfected mice varies between strains of mice in a manner largely independent of the proviral content. previous linkage analysis in the mouse suggested that the lps locus was associated with steady-state levels of mmtv rna. the lps locus mediates the mouse's response to the injection of lipopolysaccharide (lps) in the responder mouse while mice with the deficient allele are incapable of responding. injecting lps-r ... | 1985 | 2998065 |
| the nucleotide sequence of the human int-1 mammary oncogene; evolutionary conservation of coding and non-coding sequences. | the mouse mammary tumor virus can induce mammary tumors in mice by proviral activation of an evolutionarily conserved cellular oncogene called int-1. here we present the nucleotide sequence of the human homologue of int-1, and compare it with the mouse gene. like the mouse gene, the human homologue contains a reading frame of 370 amino acids, with only four substitutions. the amino acid changes are all in the hydrophobic leader domain of the int-1 encoded protein, and do not significantly alter ... | 1985 | 2998762 |
| immunohistochemical detection of mammary tumor virus antigens in sweat and sebaceous glands of mice. | mammary tumor virus (mtv) antigens in both sexes of grs/a, shn and c3h mice were examined in the sweat and sebaceous glands by immunoperoxidase technique using antiserum against gp52, envelope protein, or p27, core protein. balb/c mice were used for reciprocal foster nursing with these inbreds to discriminate the expression of endogenous mtv from that of exogenous mtv. both antigens were first detected around the age of 4 months in the sweat glands of mice with endogenous gr- or shn- mtv. a line ... | 1985 | 2998831 |
| cell anchorage determines whether mammary tumor virus glycoproteins are processed for plasma membranes or secretion. | the subcellular localization of mouse mammary tumor virus (mmtv) glycoproteins was analyzed in infected and cloned rat hepatocarcinoma cells cultured with the mmtv transcriptional inducer dexamethasone. when reacted with protein a-coated erythrocytes in the presence of antisera specific for viral glycoproteins or with fluorescent antisera, only some of the cells acquired surface label. this diversity was dependent on cell anchorage to the substratum. in general, the more rounded, less adherent c ... | 1985 | 2999161 |
| androgen regulates mmtv rna in the short-term in s115 mouse mammary tumour cells. | this report demonstrates that androgens as well as glucocorticoids can regulate mmtv rna production in the short term. in s115 mouse mammary tumour cells, mmtv rna accumulation is regulated within hours by androgen, at a time before any increase in dna synthesis can be detected, thus providing a marker of an early postreceptor molecular event in steroid action on these cells. androgen acts via its own receptor and not by cross-binding to the glucocorticoid receptor. the effects are at transcript ... | 1985 | 2999512 |
| effect of n-(4-hydroxyphenyl)retinamide on murine mammary tumor cells in culture. | the effects of n-(4-hydroxyphenyl)retinamide (hpr), a synthetic analogue of vitamin a, on cell morphology, cell cycle kinetics, cytoplasmic matrix, and expression of murine mammary tumor virus (mumtv) in mumtv-infected murine mammary tumor cells (gr-3a) were determined. cellular uptake of hpr was rapid and linear, with zero-order kinetics, during the first 30 minutes of incubation. flow cytometric analysis of cells treated with nontoxic levels of hpr (10 microm) for 48 hours revealed a reduction ... | 1985 | 2999720 |
| detection of virus antigen in male breast cancer. | | 1985 | 3000787 |
| restriction endonuclease map of endogenous mouse mammary tumor virus loci in gr, dba, and nfs mice. | mouse mammary tumor virus (mmtv) is integrated in the genome of most mice as an endogenous provirus. two of these mmtv proviral loci (mtv-1 and mtv-2) are associated with virus expression and tumorigenicity. we prepared restriction endonuclease maps of the endogenous mmtv proviruses in two strains, dba and gr, which contain the mtv-1 and mtv-2 loci, plus a third strain, nfs, which has a low mammary tumor incidence. we find that all these mouse strains have certain mmtv loci in common even though ... | 1986 | 3002033 |
| a common mouse mammary tumor virus integration site in chemically induced precancerous mammary hyperplasias. | mammary carcinomas can be induced by chemical and hormonal as well as viral carcinogens. irrespective of the class of inducer, these tumors develop in discrete stages, of which alveolar hyperplasia is one of the earliest identifiable. since carcinogenesis by the mammary tumor virus is now thought to involve proviral activation of adjacent cell genes at specific loci, we sought to determine if a similar mechanism also played a role in chemical and hormonal carcinogenesis and if its role was stage ... | 1986 | 3002039 |
| transcription of integrated mmtv ltr dna in fibroblast clones is not associated with dna methylation but with the integration site. | by transfecting 3t3 tk- fibroblasts with a plasmid dna containing the mmtv ltr promotor and the thymidine kinase gene, we have isolated tk+ clones that contain only one copy of the recombinant dna. the newly acquired dna is integrated at different sites in each tk+ clones and can be amplified as a tandem repeat in some cases. the basal level of expression of the newly acquired ltr sequence is variable among the tk+ clones studied. among those producing detectable amounts of mmtv rna, we found th ... | 1985 | 3002496 |
| [expression of mmtv proviruses in lymphopoietic organs of c3h bi mice]. | we show that transcription of mmtv proviruses takes place in lymphopoietic tissues (spleen, thymus) of c3h bi mice, a strain with high incidence of tumors. this transcription is found in the spleen of 21 day old mice but is no longer detectable in the spleen of 4 month old mice. in the mammary tumor, the 3.8 kb rna (24s) which encodes the viral envelope proteins is well transcribed whereas the 1.7 kb rna (13 s) is barely detectable. in contrast, the 1.7 kb (13 s) is the major species present in ... | 1985 | 3002567 |
| 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 |
| construction of a retroviral cdna version of the int-1 mammary oncogene and its expression in vitro. | the int-1 mammary oncogene is activated by proviruses of the mouse mammary tumor virus in many different mammary tumors. we have inserted a genomic fragment containing the protein-encoding domain of the gene into the retroviral shuttle vector pzipneosv(x)1. after one round of virus replication we recovered recombinant proviral dna containing a correctly spliced copy of int-1. in vitro transcription of this cdna version of int-1 using sp6 polymerase and translation in a reticulocyte lysate yielde ... | 1986 | 3003692 |
| a complete library of point substitution mutations in the glucocorticoid response element of mouse mammary tumor virus. | the glucocorticoid response element (gre) of mouse mammary tumor virus (mmtv) was chemically synthesized as two complementary dna strands bearing cohesive termini. during automated synthesis, random mutations were introduced into the dna by "doping" each of the four nucleoside phosphoramidites (a, g, c, and t) with a low level of the other three. these preparations were annealed and cloned into an m13 phage vector to produce a library of gre mutants. mutations within the synthesized region were ... | 1986 | 3003746 |
| cyclic amp suppresses expression of v-rash oncogene linked to the mouse mammary tumor virus promoter. | clone 433.3 of nih 3t3 cells is a stable carrier of the mmtv ltr:v-rash chimeric dna. only in the presence of dexamethasone (a synthetic glucocorticoid), 433.3 cells exhibit an induced level of p21 transforming protein and phenotypic transformation. n6,o2'-dibutyryl camp (dbcamp) antagonized the effect of dexamethasone in a time - and concentration - dependent manner. dbcamp (5 x 10(-4)m) added 18 hr prior to the addition of dexamethasone (10(-7)m) almost completely blocked the hormone effect: c ... | 1986 | 3004443 |
| expression of retroviral sequences and oncogenes in murine hepatocellular tumors. | the expression of endogenous retroviral sequences and of three cellular oncogenes was examined in three hepatocellular adenomas and in four carcinomas induced in male c57bl/6jdp x c3hf/dp f1 (hereafter called b6c3f1) mice by a single dose of nitrosodiethylamine, in five carcinomas that arose spontaneously in male c3hf mice, and in the livers of normal age-matched control mice. in all of these adenomas and carcinomas, there was increased expression of moloney murine leukemia virus- and intraciste ... | 1986 | 3004709 |
| binding of the human glucocorticoid receptor to defined regions in the human growth hormone and placental lactogen genes. | an in vitro competition assay was used to investigate whether binding sites for the human glucocorticoid receptor occur in the human genes for growth hormone (hgh) and placental lactogen (chorionic somatomammotropin, hcs). these genes display 95% sequence homology. two receptor-binding regions were found in the hgh gene, one of which is located within 290 bp upstream, and one within 251 bp downstream from the transcription initiation site. two binding regions homologous to those in the hgh gene ... | 1985 | 3004851 |
| hormonal regulation of cell surface expression of the major histocompatibility antigen h-2ld in transfected cells. | the murine major histocompatibility antigens are cell surface glycoproteins which play an important role in the recognition of foreign antigens by cytotoxic t lymphocytes. modulation of the level of expression of histocompatibility antigens could therefore be useful for the study of the interaction between the antigen presenting cells and t lymphocytes. the glucocorticoid hormone-inducible promoter, located in the long terminal repeat of mouse mammary tumor virus, was used to replace the promote ... | 1985 | 3004961 |
| [the murine mammary tumor virus (mumtv) and the association with breast cancer]. | | 1985 | 3005145 |
| interference of mouse mammary tumor virus replication by ptt.119 [p-fluoro-l-phe-m-bis-(2-chloroethyl)amino-l-phe-met ethoxy hcl]--an antitumor agent. | ptt.119 [p-fluoro-l-phe-m-bis-(2-chloroethyl)-amino-l-phe-met ethoxy hcl] is a new bifunctional alkylating compound that possesses both cytolytic and antiviral activities. continuous treatment of mouse mammary tumor cells with 15 microm ptt.119 reduced production of the b-type retrovirus murine mammary tumor virus (mumtv). mumtv levels in ptt.119-treated cultures were reduced by 31% in the first 24 hours; an additional 24 hours of treatment resulted in a further reduction of 70%. these reduction ... | 1986 | 3005743 |
| [immunohistochemical studies with retrovirus-specific antibodies in benign and malignant diseases of the breast]. | | 1985 | 3006378 |
| a new site of integration for mouse mammary tumor virus proviral dna common to balb/cf(c3h) mammary and kidney adenocarcinomas. | the balb/cf/cd substrain of mice, developed by inbreeding and selection, shows a 70% incidence of spontaneous kidney adenocarcinomas. initially foster-nursed on c3h mothers, these mice no longer produce mammary tumors, but there is evidence that mouse mammary tumor virus (mmtv) is involved in the formation of these renal carcinomas. we identified a chromosomal region called int-41, representing a locus interrupted by the integration of an exogenous mmtv provirus in a balb/c mammary tumor. we fou ... | 1986 | 3007110 |
| serologic responses to murine mammary tumor virus (mumtv) in mumtv-exposed laboratory personnel. | a retrospective study was conducted to determine whether exposure to murine mammary tumor virus (mumtv) induced mumtv-specific serologic responses among intramural laboratory personnel. results obtained with a panel of five purified structural proteins of the riii mouse strain milk-derived mumtv (gp55, gp34, p28, p18, and p12), by means of the enzyme-linked immunosorbent assay to assess antibody binding, established that mumtv exposure resulted in highly significant increases in serologic respon ... | 1986 | 3007844 |
| the effects of 2-deoxyglucose and tunicamycin on the biosynthesis of the murine mammary tumor virus proteins, and on the assembly and release of the virus. | the role of glycosylation in the biosynthesis, processing, and shedding of the murine mammary tumor virus (mumtv) glycoproteins and in virus production was investigated in a clonal mammary tumor cell line, gr-3a, using two inhibitors of protein glycosylation, 2-deoxyglucose (2-dg) and tunicamycin (tm). it was found that both 2-dg and tm completely inhibited the synthesis of the mumtv envelope precursor polyprotein, pr70env, and, as a consequence, the synthesis of the viral glycoproteins gp52 and ... | 1986 | 3008416 |
| immunohistochemical expression of mammary tumor virus antigens in mammary glands of virgin mice, in relation to mtv genes. | mtv antigens in the resting mammary glands of grs/a, shn, c3h, and balb/c virgin mice were detected by immunoperoxidase techniques using antiserum against mtv whole virion, gp 52 or p 25 to differentiate the expression between endogenous and exogenous mtv. balb/c mice were crossed to infect mtv into each reciprocal hybrid or fosternursed inbred. immunohistochemical stainings of gp 52 in the formol-fixed sections were almost the same as those of the whole mtv virion, and the results on various ca ... | 1986 | 3008497 |
| [identification of the nucleotide sequences specific for the 5'-flanking regions of the genes regulated by glucocorticoids by a computer analysis method]. | nucleotide sequences of 5'-flanking regions of 11 glucocorticoid-regulated genes and 14 genes non-regulated by these hormones were studied using context computer analysis. consensus tgttct, previously found in dna fragments protected by glucocorticoid-receptor complexes from dnaase i digestion, was shown to be nonspecific for glucocorticoid-regulated genes. however, the analysis of sequences flanking the tgttct consensus has revealed that only glucocorticoid-regulated genes contain four regularl ... | 1986 | 3008884 |
| glucocorticoid inhibition of c-myc, c-myb, and c-ki-ras expression in a mouse lymphoma cell line. | glucocorticoid hormone treatment of certain t-cell-derived lymphomas and leukemias and of immature thymocytes results in cell death. furthermore, glucocorticoid-mediated killing of s49 mouse lymphoma cells appears to involve the control of the cell cycle; i.e., s49 cells treated with glucocorticoids are arrested in g1 of the cell cycle when events controlling cell proliferation occur. the protooncogenes, c-myc, c-myb, and c-ki-ras may be involved in cell cycle regulation and proliferation state ... | 1986 | 3008988 |
| high murine mammary tumor virus expression in milk in a low mammary tumor mouse strain and high incidence of mammary tumor in hybrids produced by crossing with another low mammary tumor mouse strain. | large amounts of murine mammary tumor virus (mmtv) were expressed in milk from a low mammary tumor mouse strain called ii-tes, established by crossbreeding dba/2 mouse strain with two strains of japanese pet mouse origin. the reciprocal hybrids of the ii-tes strain and oz-f strain, another low mammary tumor strain of japanese pet mouse origin, developed early-appearing mammary tumors at a high rate, and large quantities of mmtv were expressed in the milk. these findings suggest that different re ... | 1986 | 3009372 |
| transfer, by selective breeding, of the pathogenic mtv-2 endogenous provirus from the gr strain to a wild mouse line free of endogenous and exogenous mouse mammary tumor virus. | the gr laboratory mouse strain has five endogenous proviral copies of the mouse mammary tumor virus (mmtv). one of these, mtv-2, is unique because it causes mammary carcinomas in virtually 100% of breeding gr females prior to 1 year of age. to facilitate studies of this locus in particular, and mammary tumorigenesis in general, we genetically tailored a new mouse line, wxg-2, which bears mtv-2 as its only endogenous mmtv provirus. the wxg-2 line was constructed by making hybrids between the gr s ... | 1986 | 3009842 |
| expression of the protein product of the mouse mammary tumor virus long terminal repeat gene in phorbol ester-treated mouse t-cell-leukemia cells. | exposure of c57bl/6 mouse el-4 t-cell leukemia cells to phorbol ester (12-o-tetradecanoylphorbol-13-acetate) (tpa) induced the synthesis of protein products encoded by the mouse mammary tumor virus (mmtv) long terminal repeat (ltr) region. analysis of tpa-treated el-4 cells with antiserum raised against a synthetic peptide predicted by the mmtv ltr open reading frame sequence detected a polypeptide migrating in gels with an apparent molecular weight of 37,000 mr, as well as three less prominent ... | 1986 | 3009859 |
| mammary tumorigenesis in feral mus cervicolor popaeus. | a pedigreed breeding population of feral mus cervicolor popaeus with a high incidence of mammary tumors, arising between 6 and 14 months of age, is described. these mice were chronically infected with a type b retrovirus which is distantly related to the mouse mammary tumor virus (mmtv) of inbred strains of mus musculus. mmtv-induced mammary tumors in inbred mice frequently (80%) contained an insertion of the viral genome into the int-1 or int-2 loci of the tumor cellular genome. these two cellu ... | 1986 | 3009873 |
| molecular cloning and long terminal repeat sequences of human endogenous retrovirus genes related to types a and b retrovirus genes. | by using a dna fragment primarily encoding the reverse transcriptase (pol) region of the syrian hamster intracisternal a particle (iap; type a retrovirus) gene as a probe, human endogenous retrovirus genes, tentatively termed herv-k genes, were cloned from a fetal human liver gene library. typical herv-k genes were 9.1 or 9.4 kilobases in length, having long terminal repeats (ltrs) of ca. 970 base pairs. many structural features commonly observed on the retrovirus ltrs, such as the tataa box, po ... | 1986 | 3009897 |
| [gene transplantation. studies of individual oncogenesis with transgenetic mice]. | | 1986 | 3009913 |
| mechanism of gene regulation by steroid hormones. | a first understanding of the molecular events on the dna level, underlying transcriptional regulation by steroid hormones, has been approached in the last 3 years by means of protein/dna interaction studies, using purified receptors. this work summarizes our knowledge of how purified glucocorticoid and progestine receptors interact with their cognate regulatory elements associated with polymerase ii dependent genes like mouse mammary tumour virus, the genes encoding human metallothionein iia, ch ... | 1986 | 3009974 |
| functional analysis of the purified glucocorticoid receptor. | glucocorticoid-receptor complex (gr) has been purified from rat liver by differential affinity for dna before and after activation, followed by ion-exchange chromatography. the purified gr has mol. wt 94,000 dalton. the protein contains three functional domains: (a) a steroid-binding domain; (b) a dna-binding domain; and (c) a domain necessary for normal biological function. a second protein, with mol. wt 72,000 dalton, copurifies with the gr. this protein does not bind steroid, does not interac ... | 1986 | 3009991 |
| concerted activation of two potential proto-oncogenes in carcinomas induced by mouse mammary tumour virus. | the induction of tumours by retroviruses lacking transduced oncogenes can involve the transcriptional or functional activation of cellular proto-oncogenes by an integrated provirus. thus, the two cellular genes int-1 and int-2, identified as common targets for activation by mouse mammary tumour virus (mmtv), may constitute previously unrecognized oncogenes. in tumours, proviral insertion at these loci leads to expression of messenger rnas which are undetectable in normal mammary glands. here we ... | 1986 | 3010125 |