Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| rna virus associated antigen in human placenta. | using indirect immunofluorescence microscopy, it was demonstrated that human cytotrophoblast of six to ten weeks gestation contains mouse mammary tumor virus associated antigen. this antigen appeared predominantly in the periphery of the cells. | 1980 | 6247956 |
| correlation between the detection of specific mouse mammary tumor proviral sequences and the presence of pulmonary metastases in mice bearing spontaneous mammary tumors. | pulmonary metastases in c3h/he mice bearing spontaneous mammary tumors were detected and characterized by histological criteria and immunocytochemical staining for mouse mammary tumor virus antigens. the same lungs containing metastases were also positive when assayed for a specific subset of mouse mammary tumor virus proviral dna sequences. these sequences, termed tumor-associated sequences, have previously been shown to be present in the dna of spontaneous mammary tumors that arise before 1 yr ... | 1980 | 6248203 |
| age- and tumor-correlated changes in functional antibody responses to mtv in neonatally infected mice. | balb/cfc3h female mice (neonatally infected with mtv) possess several different specific antibody activities measured functionally by reactivity with mtv-associated antigens expressed on the surface of isologous mtv-induced mammary tumor target cells. all females when young develop serum antibody which can block specific t-cell cytotoxic activity of balb/cfc3h spleen cells; this activity remains detectable throughout life. in addition, recruiting antibody is found in the post-weaning stage. this ... | 1980 | 6248467 |
| quantification of mouse mammary tumor virus structural proteins in hormone-induced mammary tumors of low mammary tumor mouse strains. | the expression of the mouse mammary tumor virus (mmtv) in hormone-induced mammary tumors was investigated by means of a radioimmunoassay for two major mmtv proteins, gp52 and p27. mmtv proteins were isolated on lectin affinity- and ion-exchange chromatography columns. the purified viral proteins were electrophoretically homogeneous and retained immunoreactivity after labelling with 125iodine. standard competition assays showed that group-specific antigenic determinants were reacting. mammary tum ... | 1980 | 6248469 |
| presence of a proteolytic activity in murine mammary tumor virus. | 1980 | 6248545 | |
| murine mammary tumor virus deficient in the major glycoprotein: biochemical and biological studies on virions produced by a lymphoma cell line. | 1980 | 6249031 | |
| isolation and characterization of low-molecular-weight dna-binding proteins from retroviruses. | 1980 | 6249039 | |
| the ganglioside content of the milk fat-globule membrane and the mouse mammary-tumour virus isolated from the milk of infected mice. partial characterization of a new disialoganglioside. | the milk fat-globule membrane and the mouse mammary-tumour virus isolated from the milk of infected swiss mice have been investigated for their content in gangliosides. when compared on the lipid phosphorus basis, viral envelope is found to contain more than twice as much lipid-bound sialic acid as fat-globule membrane. the ganglioside patterns of these two structures appear rather similar, except for the occurrence in fat-globule membrane of a low ganglioside homolog, presumably gm2, not detect ... | 1980 | 6249587 |
| mouse mammary tumour virus-related antigens in core-like density fractions from large samples of women's milk. | 1980 | 6249609 | |
| lack of evidence for non-virion cell surface antigens on virally-induced murine mammary tumor cell. | 1980 | 6250851 | |
| localization of a gene for expression of mouse mammary tumor virus antigens in the gr/mtv-2- mouse strain. | the gr/mtv-2- mouse strain is congenic to the gr strain but lacks the mtv-2 gene for high amounts of mouse mammary tumor virus (mmtv) virion particles in the milk and early mammary tumors. with a sensitive competition radioimmunoassay for individual viral proteins of mmtv, substantial amounts of the gag proteins p27 and p10 could still be detected in extracts of the mammary glands of gr/mtv-2- mice, but essentially no viral envelope antigens. the genetic transmission of the mmtv gag expression i ... | 1980 | 6251153 |
| molecular and morphological evidence for type b retrovirus (oncornavirus) expression in human mammary carcinoma. an overview using scanning electron microscopy, immunoperoxidase staining, and transmission electron microscopy. | approximately 45% of human mammary carcinoma cases express an antigen which cross reacts in formalin fixed tissues with antiserum prepared against the purified 52,000 molecular weight structural glycoprotein (gp52) of mouse mammary tumor virus (mmtv). breast carcinoma immunoperoxidase marking is abolished by antiserum adsorption with mmtv. adsorption with murine leukemia virus failed to block immunoperoxidase marking. no correlation was seen in the cases analyzed between gp52-like antigen expres ... | 1980 | 6251536 |
| immunoelectron microscopic studies using monoclonal antibodies to mouse mammary tumor virus antigens as probes of the cell surface with the unlabeled antibody hemocyanin bridge. | 1980 | 6251538 | |
| stability of characters of mammary tumors in balb/cfriii mice. | the biological and morphological characteristics of mammary tumors in balb/c mice infected with riii mammary tumor virus (mtv) by foster nursing have substantially kept stable and unchanged after 20 years, 53 inbred generations and transfer of the strain from perugia to pisa. this suggests that the causal mtv keeps unaltered in time its biological properties. | 1980 | 6251587 |
| gene order of murine mammary tumor virus gag proteins and env proteins. | 1980 | 6251618 | |
| [detection of antigens immunologically related to the envelope antigens of mouse mammary gland cancer virus antigens in human breast cancer tissue]. | a highly sensitive method of electroimmunodiffusion in acetate cellulose films developed by g.i. abelev on the principle of isotachophoresis was used for the detection in human mammary gland carcinoma (hmgc) of an antigen related to envelope antigens of mouse mammary gland cancer (mmgc) virus. in 4 out of 10 hmgc cases, fractions of proteins with molecular weight about 50,000 d previously isolated in paag with sodium dodecyl sulphate were found to contain an antigen reacting with the antiserum t ... | 1980 | 6251635 |
| detection and characterization of mouse mammary tumor virus cell surface antigens: estimation of antigen abundance by protein a assay. | antisera against the following mouse mammary tumor virus (mmtv) structural proteins were used to detect mmtv cell surface antigens: (i) the 27,000-dalton nucleoid protein, p27; (ii) the 36,000-dalton envelope glycoprotein, gp36; and (iii) the 52,000-dalton exterior envelope glycoprotein, gp52. we report here the development of an adherent-cell isotopic staphylococcal protein a (spa) test (ispat) for mmtv structural proteins which allows for the detection of an mmtv membrane-associated antigen as ... | 1980 | 6252344 |
| murine mammary tumor virus structural protein interactions: formation of oligomeric complexes with cleavable cross-linking agents. | murine mammary tumor virus protein interactions in the intact virion structure were studied with the use of the cleavable cross-linking reagents dithiobis(succinimidyl propionate) and methyl 4-mercaptobutyrimidate hydrochloride. cross-linked oligomeric complexes of murine mammary tumor virus proteins were analyzed by two-dimensional gel electrophoresis. among the complexes most consistently formed were a heterodimer of the two glycoproteins gp36 and gp52, the homodimer of gp36, and the homotrime ... | 1980 | 6252348 |
| short gastric veins as the major portal of entry for milk-borne murine mammary tumor virus. | the flow pattern of the short gastric veins that drain the fundic portion of the stomach appeared to influence mammary tumorigenesis. in i and c57bl mice, strains that are highly resistant to murine mammary tumor virus (mumtv)-induced mammary tumorigenesis, the short gastric veins empty directly into the splenic vein outside the spleen, connecting with the portal system. in (c57bl x i)f1 mice, which are highly susceptible to mumtv-induced mammary tumorigenesis, the short gastric veins empty dire ... | 1980 | 6252362 |
| [genesis of breast cancer: a multifactorial etiology]. | 1980 | 6252427 | |
| [detection of mmtv gp52 in c3h and c3hf strain mice]. | immunofluorescence in paraffine sections demonstrated the difference in expression of the membrane glycoprotein of mouse mammary tumor virus (gp52) in two mouse sublines: c3h and c3hf. in the c3hf the glycoprotein becomes detectable in the mammary gland in the second part of pregnancy while in c3h line mature females before pregnancy. no viral glycoprotein could be found in the spleen, liver, kidneys and other organs in males and females of the two sublines or in c3h embryos. | 1980 | 6252698 |
| [increased immunologic reactivity against hepatoma 22a cells in mtv-infected c3h mice in comparison to mtv-free mice]. | some tumors of no mammary tissue origin (sarcoma, hepatoma) grew more effectively in mtv-free mice (c3hf) as compared with mtv-infected mice (c3h/he), whereas the tumors of mammary gland origin grew more rapidly in the latter ones. it has been shown that c3h/he mice develop a stronger specific immune reaction against hepatoma 22a cells than do c3h/f mice and that the animals of mtv-bearing subline exhibit a higher natural killer activity against these cells. | 1980 | 6252986 |
| construction and characterization of molecular clones containing integrated mouse mammary tumor virus sequences. | 1980 | 6253190 | |
| genomic location of mouse mammary tumor virus proviral dna in normal mouse tissue and in mammary tumors. | 1980 | 6253191 | |
| summary: molecular biology of viral oncogenes. | 1980 | 6253205 | |
| mammary tumor virus antigen expression in inbred mouse strains of european origin established in japan. | expression of the mammary tumor virus (mtv) antigen in the milk from inbred mouse strains maintained in japanese laboratories was investigated by means of the immunodiffusion test (id) and the results were compared with the incidence of mammary tumors in breeding females of identical strains. japanese strains tested were classified into two groups. the dd/tbr, ddd and kf strains were derived from "dd" stock mice, and they showed equally high incidences of mtv antigen expression in the milk, thou ... | 1980 | 6253345 |
| reevaluation of the effect of mouse mammary tumor virus infection on the balb/c mouse hyperplastic outgrowth. | the balb/c (c-) mouse hyperplastic outgrowth line (d1) was used to study murine mammary tumor virus (mumtv) expression in both d1 and tumors derived from d1. d1 was transplanted into virus-infected balb/cfc3h (c+) and virus-uninfected c- animals. in duplicate studies, tumor incidence was the same in both groups. however, the tumor latency period was longer for d1 transplanted into c+ mice (d1/c+) than for d1 transplanted into c- mice (d1/c-). mumtv was detected in 85% of d1/c+ outgrowths and in ... | 1980 | 6253710 |
| [viral etiology of breast cancer]. | 1980 | 6253765 | |
| ubiquity of natural antibodies to the mammary tumour virus in mice. | sera of female and male mice from eleven inbred mouse strains collected at either 4, 12, 36 or 60 weeks of age were tested for the presence of natural antibodies to the murine mammary tumour virus by means of the sepharose bead immunofluorescence assay. antibodies to the virus proved to be ubiquitous, but pronounced strain differences were found in titer and onset of antibody production. these differences were related to neither release of virus in the milk nor susceptibility to spontaneous mamm ... | 1980 | 6254462 |
| antigenic modulation of mammary tumour virus envelope antigen or gr thymic lymphoma cells in relation to expressions of h-2, tl cell-surface antigens and thy1. | the mlr antigen, a mammary tumour virus-induced antigen on the surface of gr thymic lymphoma cells (grsl) can be modulated from the cell surface upon incubation with specific antiserum for 1-2 h at 37 degrees c, followed by washing the cells. in contrast, a number of other cell-surface antigens on these grsl cells cannot be modulated under similar conditions. these antigens include histocompatibility antigens of the h-2 complex (h-2.8 of the k-end and h-2dx(d) of the h-2dx haplotype) and two thy ... | 1980 | 6254554 |
| a unique glycoprotein containing gr-mouse mammary tumor virus peptides and additional peptides unrelated to viral structural proteins. | a glycoprotein of molecular weight 130,000 (gp130) has been precipitated from the cytoplasm of gr-strain mouse mammary tumor (gr-mmt) cells by a rabbit antiserum (anti-mmtv) to gr-strain mouse mammary tumor virus (gr-mmtv). this protein was not precipitated by antisera specific for detergent-disrupted c3h-strain mmtv (c3h-mmtv); c3h-mmtv glycoproteins; c3h-mmtv nonglycosylated proteins; gr-mmtv p25 or p12; riii strain (milk) mmtv proteins; or rauscher murine leukemia virus (r-mulv) proteins; nor ... | 1980 | 6254670 |
| dna binding and unwinding activities associated with intracytoplasmic a particles isolated from mouse mammary tumors. | intracytoplasmic a particles (cap), previously identified as probably cytoplasmic nucleocapsid precursor structures to mouse mammary tumour virus (mmtv), possess both dna binding and dna unwinding activities, cap proteins bind to both single-stranded (ss)- and double-stranded (ds)dna, with the ssdna slightly preferred. this activity was linear over a 30-fold concentration of a particle protein and was not affected by nacl concentrations as high as 0.6 m or ph changes over a wide range. dna bindi ... | 1980 | 6255067 |
| proviruses of mouse mammary tumor virus in normal and neoplastic tissues from gr and c3hf mouse strains. | we analyzed two experimental situations to assess the role of endogenous mouse mammary tumor virus (mmtv) dna in the genesis of mammary carcinomas. (i) gr mice carry in their germ line one or more proviruses indistinguishable by limited restriction mapping from the proviruses introduced into cells by experimental infection with the highly tumorigenic virus isolated from gr mouse milk, mmtv(gr). most tumors arising in gr mice contain one or more proviruses at various sites in tumor dna in additio ... | 1980 | 6255172 |
| analysis of secondary modifications of mouse mammary tumor virus proteins by two-dimensional gel electrophoresis. | the structural proteins of mouse mammary tumor virus (mmtv) were analyzed by two-dimensional electrophoresis on isoelectric focusing and sodium dodecyl sulfate gels. many of the viral proteins displayed heterogeneity in charge due to variable contents of carbohydrates (in particular, sialic acid) and phosphate residues. neuraminidase treatment of the virions influenced the isoelectric pattern of the envelope glycoproteins. the glycoproteins of an mmtv variant which was attenuated by replication ... | 1980 | 6255175 |
| structure and processing of the mouse mammary tumor virus glycoprotein precursor pr73env. | the polyprotein precursor to the envelope glycoproteins of mouse mammary tumor virus was investigated by using subcellular fractionation procedures, pactomycin mapping techniques, tunicamycin inhibition of glycosylation, and endo-beta-n-acetyl glucosaminidase h-catalyzed removal of glycosylated residues in order to characterize the biosynthesis and processing of the precursor. the results suggest that the precursor (pr73env) is synthesized on the rough endoplasmic reticulum as a transmembrane pr ... | 1980 | 6255176 |
| selective amplification of mouse mammary tumor virus in mammary tumors of gr mice. | dnas extracted from the mammary tumors of gr mice were analyzed for mouse mammary tumor virus proviral sequences by the restriction enzyme-southern blot procedure. the tumor dnas contain more proviral copies of mouse mammary tumor virus than dna from a nonmalignant tissue. the degree of proviral amplification is small (ca. one to five additional copies) and appears to be variable from tumor to tumor. the restriction patterns of the amplified proviral sequences suggest a clonal origin for the tum ... | 1980 | 6255199 |
| the extraction by micrococcal nuclease of glucocorticoid receptors and mouse mammary tumor virus dna sequences is dissociated. | glucocorticoid receptors (rg) and mammary tumor virus (mm-tv) dna sequences were extracted by micrococcal nuclease digestion from the nuclei of c3h mouse mammary tumor cells in order to specify their relative distribution in chromatin. rg was labelled and translocated into the nuclei by incubating cells with 3h dexamethasone (3h dex). the purified nuclei were then treated at 2 degrees c with micrococcal nuclease. three chromatin fractions were successively obtained: an isotonic extract (ne3h1), ... | 1980 | 6255415 |
| interferon induced inhibition of mouse mammary tumor virus production. | treatment of murine cells chronically infected with mouse mammary tumor virus with interferon resulted in a marked inhibition of extracellular virus production. this inhibition occurred despite the lack of effect on the transcription or translation of viral rna. interferon treatment did not alter the steady-state level of intracellular viral rna as determined by hybridization of total cellular and polysomal poly(a) containing rna with mouse mammary tumor virus complementary dna. additionally, an ... | 1980 | 6180037 |
| isolation of glucocorticoid-unresponsive rat hepatoma cells by fluorescence-activated cell sorting. | we have used a mouse mammary tumor virus (mmtv)-infected rat hepatoma cell line as a model system for studying glucocorticoid action. these cells induce tyrosine aminotransferase and mmtv in response to the synthetic glucocorticoid, dexamethasone. the major viral antigen, a glycoprotein of 52,000 daltons (gp52), appears on the surface of infected cells in amounts which reflect the cytoplasmic content of viral rna. using an anti-gp52 antiserum and a fluorescence-activated cell sorter (facs), we h ... | 1980 | 6105925 |
| tumor associated markers in breast cancer. | 1980 | 6172278 | |
| noncoordinate expression of murine mammary tumor virus gene products. | 1980 | 6256936 | |
| characterization of endogenous and exogenous mouse mammary tumor virus proviral dna with site-specific molecular clones. | restriction fragments of the mouse mammary tumor virus (mmtv) proviral dna were obtained by molecular cloning procedures. a 4-kilobase fragment delimited by two psti sites was isolated from unintegrated, linear mmtv dna and amplified in the pbr322 plasmid vector. ecori fragments of proviral dna, integrated into the genome of a gr mammary tumor cell line, were isolated as lambda recombinant molecules. five different recombinant phages which contained the 3' region of the mmtv proviral dna and adj ... | 1980 | 6257924 |
| identification and partial characterization of an endogenous form of mouse mammary tumor virus that is transcribed into the virion-associated rna genome. | restriction mapping demonstrated the presence of several distinct proviral forms of mouse mammary tumor virus in the genome of gr mice. one of these proviruses (gr-mtv-2) was highly amplified in gr 3a cells, a cell line derived from a gr mammary tumor. by the criterion of restriction mapping, the amplified gr-mtv-2 provirus found in gr 3a cells was identical to the provirus found in m1.19 cells, a rat cell line infected with virions obtained from gr 3a culture fluid. this result clearly implies ... | 1980 | 6258150 |
| development and characterization of mouse hyperplastic mammary outgrowth lines from balb/cfc3h hyperplastic alveolar nodules. | five hyperplastic outgrowth lines were developed by serial transplantation of hyperplastic alveolar nodules from balb/cfc3h mice into balb/c hosts. the lines were used to study the biology, morphology, and virology of premalignant tissue originating in mouse mammary tumor virus (mumtv)-positive animals. the five lines differed with respect to tumor potential and growth characteristics, corroborating the previous evidence that mumtv-positive hyperplastic alveolar nodules are biologically heteroge ... | 1980 | 6258774 |
| geographic and family studies of immunological responses to antigens of the murine mammary tumor virus in sera of patients with breast cancer. | sera of breast cancer patients from the united states, india, east africa and china as well as from their families and from healthy women were assayed for antibodies reactive with the murine mammary tumor virus (mumtv). detection was by an enzyme-linked immunoassay recently developed in our laboratory. in the women with breast cancer, 62% of the east africans, 28% of the indians, 19% of the americans but only 5% of the chinese had antibody to mumtv. among healthy women, 21% of the africans, 3% o ... | 1980 | 6264656 |
| attempts to obtain monoclonal antibody against mmtv tumors. | 1980 | 6261429 | |
| the origin and structure of endogenous retroviral dna. | dna related to the genomes of avian leukosis viruses (alv) and mouse mammary tumor viruses (mmtv) is widely distributed among normal chickens and mice. we have used restriction mapping techniques to compare individuals from inbred and outbred populations with respect to genetically-transmitted proviral dna, in efforts to understand its origins and functions. we have found that outbred animals have variable numbers of alv and mmtv proviruses located at various sites in their host genomes, with so ... | 1980 | 6261653 |
| selenium-mediated inhibition of mouse mammary tumorigenesis. | the effects of selenium of mouse mammary tumorigenesis were examined in 2 systems. balb/cfc3h (mumtv-s positive) given 2 and 6 ppm selenium in the drinking water and maintained as breeding mice, had significantly lower incidences of mammary tumors (48% and 12%, respectively) than untreated control mice (82%). selenium at 4 ppm inhibited the tumor-producing capabilities of only 1 of 4 preneoplastic outgrowth lines maintained in balb/c (mumtv-s negative) mice. selenium at 2, 4 and 6 ppm had no eff ... | 1980 | 6261942 |
| expression of mouse mammary tumour virus related antigens in experimentally induced leukaemias of strain icrc. | 1980 | 6262218 | |
| distribution of mouse mammary tumour virus antigens in riii mice as detected by immunofluorescence on tissue sections and by immunoassays in sera and organ extracts. | organs of riii mice at various physiological stages were tested for mouse mammary tumour virus (mmtv) antigen expression. indirect immunofluorescence was used with three monospecific antisera to localize one envelope glycoprotein, gp47, and two core proteins, p28 and p8. these virus-specific antigens gave characteristic fluorescent patterns in the mammary tissues and were also detected in thymus and salivary gland sections of some mice. the amounts of antigens gp47 and p28 were measured by immun ... | 1980 | 6262440 |
| evidence of separate pathways for viral and chemical carcinogenesis in c3h/stwi mouse mammary glands. | 1980 | 6270008 | |
| the effect of diet on autogenous immunity to mouse mammary tumor virus in c3h/bi mice. | antibody levels to mouse mammary tumor virus (mumtv) in sera of c3h/bi, c57bl/6 and akr mice were assayed by an enzyme-linked immunosorbent assay (elisa). it was found that antibody levels to mumtv were highest in sera of c3h/bi females which have a high incidence of breast cancer and low in male c3h/bi and female c3h/bi foster-nursed on c57bl/6 females. sera of c57bl/6 and akr mice showed very low or undetectable levels of antibody to mumtv. reduction of caloric intake sufficient to inhibit mam ... | 1980 | 6260696 |
| the nature of cancer and the mechanisms of its control: a review. | observations on the nature of spontaneous tumours of mammary gland origin in mice, published over a 60-year period in 320 papers, are reviewed. data presented are (1) development of adequate experimental mice; (2) comparative studies on transplantable, chemically induced and spontaneous tumours by diverse genetic procedures, and (3) tumour regressions obtained with nucleosides. the fundamental conclusion derived from these data is that a genetic change, comparable to a somatic mutation, is invol ... | 1980 | 6260434 |
| neoplastic and preneoplastic lesions induced in female c3h mice by diets containing diethylstilbestrol or 17 beta-estradiol. | to study the long term effects of estrogenic diets, 2160 virgin female c3h/hel mice, having a high titer to the mammary tumor virus factor (mmtv), were fed diets containing 0, 10, 100, 500, or 1000 ppb diethylstilbestrol (des) or 100, 1000, or 5000 ppb 17 beta-estradiol (e2) from 6 to 110 weeks of age; 1368 virgin female c3heb/fej mice, having a low titer to the mmtv, were fed diets containing 0, 10, 1000, or 500 ppb des from 6 to 136 weeks. in estrogen-treated mice, the incidence of cervical ad ... | 1980 | 7217862 |
| antibodies reactive with the mouse mammary tumor virus in sera of breast cancer patients. | igg binding to purified mouse mammary tumor virus (mumtv) was quantitated by an enzyme-linked immunoassay (elisa) using sera from patients with breast cancer or benign breast disease, or from healthy age-matched controls. significantly greater binding (p<0.01) was found in breast-cancer-derived sera than in the other categories. in addition to igg reactivity, three breast cancer sera also possessed iga and igm reactive with mumtv by the elisa assay. only igg was reactive in the majority of sera ... | 1980 | 14768700 |
| mammary tumor virus. investigations in mouse and man. | 1981 | 6305702 | |
| glucocorticoid regulation of the ha-musv p21 gene conferred by sequences from mouse mammary tumor virus. | molecular chimeras with the p21 transforming gene of harvey murine sarcoma virus linked to dna containing the long terminal repeat (ltr) or mouse mammary tumor virus (mmtv) have been constructed. transformants of nih 3t3 cells induced by transfection with mmtv ltr-p21 hybrid dna have been identified that express the normal p21 gene product. the levels of p21 rna and protein in these transformants are regulated by physiological concentrations of dexamethasone, a synthetic glucocorticoid hormone. ... | 1981 | 6277498 |
| mammary tumor virus dna contains sequences required for its hormone-regulated transcription. | glucocorticoids regulate the rate of transcription of integrated murine mammary tumor virus (mtv) genes in most clones of mtv-infected rat hepatoma tissue culture (htc) cells. to determine whether hormonal regulation is mediated from flanking cellular sequences or rather from within the viral dna, we analyzed the relative rates of transcription of mtv and adjacent htc sequences in two lines of infected htc cells, j2.15 and j2.17, each of which contains a single insertion of mtv dna. in addition, ... | 1981 | 6277499 |
| structure, stability, methylation, expression and glucocorticoid induction of endogenous and transfected proviral genes of mouse mammary tumor virus in mouse fibroblasts. | a sequence of mouse genomic dna containing an endogenous mouse mammary tumor virus (mmtv) provirus, which was isolated by molecular cloning in lambda vector phage, has been reintroduced into cultured mouse l cells, using the thymidine-kinase cotransfection technique. individual cell clones that acquired the transfected mmtv proviral dna have been isolated. the transfected dna remains stable in these cells and does not become methylated. it is transcribed into mmtv rna, and the transcription is s ... | 1981 | 6277735 |
| independence of h-2 and viral antigens on the cell surface and absence of h-2 antigens on murine leukemia virus and mouse mammary tumor virus particles. | by indirect immunoelectron microscopy we tested for the presence of h-2 antigens on murine mammary tumor virus (mmtv) and murine leukemia virus (mulv) particles. the association of h-2 antigens and viral antigens on the virus-infected cell surface was investigated with antibody-induced redistribution. mammary tumor cells and leukemia cell lines with different h-2 genotypes and carrying different mumtv or mulv were used. no h-2 antigens could be demonstrated on the envelope of mmtv and mulv parti ... | 1981 | 6277784 |
| natural cell-mediated immunity to mouse mammary tumor virus and its relevance to host immune defences. | 1981 | 6279022 | |
| organization of proviral dna and protein composition of hormonally stimulated c57bl/10 strain-associated mouse mammary tumor virus. | two continuous lines, bl-matu/a1 and bl-matu/s6, were established from c57bl/10 mammary adenocarcinomas induced by dmba-prolactin-estradiol treatment. under in vivo stimulation with dexamethasone, insulin, prolactin, and prostaglandin a1, the cells produce detectable amounts of b-type particles with biochemical properties similar to the gr-mumtv. analysis of restriction endonuclease-generated fragments of cellular dna revealed identical patterns in the integration sites and internal recognition ... | 1981 | 6280079 |
| [cross-reaction of human breast cancers with the envelope glycoprotein gp 52 of the mouse mamma tumorvirus (mmtv)]. | 1981 | 6289552 | |
| [electron microscopical observations of the junctional elements in virus-producing murine mammary tumors]. | 1981 | 6289553 | |
| complementary dna copies of leukemia and sarcoma virus rna contain sequences of deoxycytidylate and deoxyguanylate. | single-stranded complementary dna (cdna) of the rna of gazdar murine sarcoma virus, gz-msv/mulv; moloney murine leukemia virus, m-mulv; mouse mammary tumor virus, mmtv; and simian sarcoma virus, ssv-1, were synthesized in endogenous reverse transcriptase reaction. gz-msv/mulv cdna was also synthesized in exogenous in vitro reverse transcriptase reactions. in the endogenous reaction, 30-35s, or 6.0- to 7.9-kilobase-length cdna transcripts were synthesized in high yield. in comparison, transcripts ... | 1981 | 6299564 |
| virus-specific cytotoxic activity to mammary tumor cells of sera from normal and tumor-bearing mice with inhibition at low dilutions. | sera from normal mice and mice bearing murine mammary tumor virus (mtv)-induced tumors showed cytotoxic reactions to the mtv-producing mm5mt/c1 cell line. the reaction could be blocked by the addition of mtv, but not of purified gp52 and p28. in sera from tumor bearers, cytotoxic responses ranged from 15 to 66%; reactivity was generally highest when the serum was diluted 32 to 128 times. the cytotoxic sera from the normal animals showed a much lower activity; again, there was a lack of cytotoxic ... | 1981 | 6260679 |
| use of an electroimmunodiffusion method on cellulose acetate films for the detection of antigenicity in human breast cancers that is related to the major core antigen of mouse mammary tumor virus (mumtv). | a highly sensitive electroimmunodiffusion method on cellulose acetate films, developed by abelev on the basis of isotachoelectrophoresis, was applied to search of mumtv-related antigenicity in tumor tissue and sera of breast cancer patients. in 2 out of 5 breast cancer extracts, protein fractions corresponding to a molecular weight of about 50,000 daltons were seen to exhibit antigenicity related to the major core antigen of mumtv (p27). this antigenicity could not be detected in the sera of the ... | 1981 | 6277267 |
| synthesis of plus strands of retroviral dna in cells infected with avian sarcoma virus and mouse mammary tumor virus. | the vast majority of plus strands synthesized in quail cells acutely infected with avian sarcoma virus were subgenomic in size, generally less than 3 kilobases (kb). a series of discrete species could be identified after agarose gel electrophoresis by annealing with various complementary dnas, indicating specificity in the initiation and termination of plus strands. the first plus strand to appear (within 2 h postinfection) was similar in length to the long redundancy at the ends of linear dna ( ... | 1981 | 6260968 |
| regulatory and coding potential of the mouse mammary tumor virus long terminal redundancy. | molecular clones containing the 3' half of newly integrated mouse mammary tumor virus (mmtv) dna with adjacent mouse cellular sequences were characterized. in addition, we cloned the long terminal redundancy joint from the unintegrated circular form of mmtv dna. the entire nucleotide sequence of the integrated and part of the unintegrated terminal redundancy was determined; this allowed us to delineate the boundaries of the mmtv long terminal redundancy, which comprises 1,327 base pairs. the pos ... | 1981 | 6260976 |
| protein-coding potential of mouse mammary tumor virus genome rna as examined by in vitro translation. | the protein-coding capacity of the mouse mammary tumor virus genome has been examined by in vitro translation of genome length and polyadenylated subgenomic fragments of viral rna. intact genome rna of about 35s programmed synthesis of the pr77gag, pr110gag and pr160gag/pol precursors seen in infected cells in vivo. polyadenylated rna fragments of 18 to 28s encoded products whose tryptic peptide maps resembled those of the nonglycosylated precursor to the envelope glycoproteins, confirming the g ... | 1981 | 6260988 |
| strain difference in the expression of mammary tumor virus antigen in the male genital organs of mice during aging. | mammary tumor virus (mtv) antigen expression was tested in the male genital organs (testis, epididymis, prostate, seminal vesicle and coagulating gland) of dd/tbr, kf and ddd strains (dd (german) mouse group), gr strain (swiss origin), shn and sln strains (different swiss origin), c3h and a strains (american origin), balb/c and c57bl strains (low mammary tumor strains), and ddf and shnf strains (mtv eliminated strains). microimmunodiffusion analysis showed that expression of mtv antigen is tissu ... | 1981 | 6274726 |
| covert infection of a mouse mammary tumor cell line with mycoplasma hyorhinis: cosedimentation with mouse mammary tumor virus in sucrose density gradients. | supernatant fluids from cultures of a mouse mammary tumor (mt) cell line were found to produce a specific cell detachment effect when inoculated into hela cells. the cell detachment factor (cdg) responsible for this effect was examined. repeated attempts to cultivate this cdf in bacteriologic, fungal, and mycoplasma media were unsuccessful. however, using the dna fluorochrome staining technique and specific immunofluorescent staining procedures, the cdf was identified positively as a noncultivab ... | 1981 | 6274789 |
| enhanced immune reactivity to hepatoma 22a cells in mtv-infected compared with mtv-free c3h mice. | the transplantability and growth rate of mouse mammary and non-mammary tumours (sarcoma and hepatoma) were compared in mtv-free (mtv-) and mtv-infected (mtv+) c3h mice. it was demonstrated that sarcoma and hepatoma, in contrast to mammary tumours, grew better in mtv- mice. the difference between c3h sublines in the growth of hepatoma transplants was found to be determined by the stronger specific immune response and higher natural lymph node cell cytotoxicity in mtv+ mice. | 1981 | 6274791 |
| dexamethasone induction of the intracellular rnas of mouse mammary tumor virus. | we have studied the kinetics of dexamethasone induction of mouse mammary tumor virus (mmtv) rnas and proteins in virus-infected rat xc cells and gr mouse mammary tumor cells. a detectable increase in viral rna in infected xc cells was present within 10 min after hormone addition, and half-maximal induction was achieved in less than 2 h. the increase in viral rna concentration was apparent first in nuclear rna and later in the cytoplasm. within the first 15 min of induction, only genome-sized rna ... | 1981 | 6275112 |
| genetic mapping of endogenous mouse mammary tumor viruses: locus characterization, segregation, and chromosomal distribution. | the restriction endonuclease ecori has been used to study the inheritance of strain difference in endogenous mouse mammary tumor virus dna sequences. this enzyme, which cleaves at only one site within the nondefective viral genome, generates dna fragments containing mouse mammary tumor virus sequences which vary in size according to the locations of ecori restriction sites in the flanking mouse sequences, thereby defining unique integration sites of the viral genome. recombinant inbred strains o ... | 1981 | 6275115 |
| expression of the murine mammary tumor virus in the milk of f1 hybrids of virus negative mouse strains. | 1981 | 6276182 | |
| the presence of b type virions in trichoepithelioma of a mouse. | 1981 | 6276609 | |
| earlier appearance of murine mammary tumor virus-associated antigens in duct-alveolus nodules induced by transplantation of fetal salivary mesenchyme into c3h mouse mammary glands. | mammary epithelium of adult c3h mice in contact with fetal salivary mesenchyme took morphogenetically a salivary gland-like pattern of growth and developed a hyperplastic nodular mass at the site of transplantation. when murine mammary tumor virus-bearing c3h mice were treated in this way, early development and high incidence of mammary cancer were observed from these nodules compared to unstimulated mammary glands of the same host. since tumor development, the viral antigens in these hyperplast ... | 1981 | 6281120 |
| lack of induction of murine mammary tumor virus expression in cultured mammary glands treated with chemical carcinogens. | 1981 | 6270025 | |
| quantitative of murine mammary tumor virus-related rna in mammary tissues of low- and high-mammary-tumor-incidence mouse strains. | lactating mammary glands and hormonally induced mammary tumors of balb/c mice from three geographically separated breeding colonies were examined by molecular hybridization, using murine mammary tumor virus (mumtv) cdna representing the entire viral genome to determine the amount of mumtv-related rna expressed in these tissues. the rna extracted from these tissues by the classical sodium dodecyl sulfate-pronase, phenol-chloroform procedure (method 1) contained barely detectable levels of mumtv-r ... | 1981 | 6270387 |
| [possible participation of endogenous mmtv virus in chemical carcinogenesis of mouse mammary glands]. | a study was made of the effect of immunization with formalinized mmtv on mammary tumor incidence in balb/c mice exposed to dimethylbenzanthracene. in mice immunized with mmtv, the incidence of mammary tumours was significantly lower and the latent period longer as compared with the control group immunized with mulv. the indirect fixed immunofluorescence technique has shown that tumour cells in both groups express gp52 and p27 antigens. the possible involvement of endogenous mmtv into chemical ca ... | 1981 | 6271307 |
| possible role of genetic cell variants in the viral induction of mouse mammary tumors. | out of three attempts to induce neoplasia in normal c57bl mammary epithelial cells with the mouse mammary tumor virus (mumtv) only one presented signs of tumorigenicity. immunofluorescence showed that virus synthesis took place in all three sublines but tumorigenicity as detected by cell aggregation viability (cav) and transplantation into syngeneic mice failed to occur in two of them. by comparison, cells from a balb/c spontaneous mammary tumor that do not express mumtv were 100% tumorigenic, w ... | 1981 | 6271665 |
| estimation of mouse mammary tumor virus gp52 abundance by protein a assay: a comparison of viral antigen expression on c3h and gr mammary tumor cells. | an adherent cell isotopic staphylococcal protein a test (ispat) was used to estimate the abundance of mouse mammary tumor virus (mmtv) gp52 cell surface antigen (csa)on mammary tumor cells. protein a assays were first utilized, not strictly as a means of antigen detection, but as a means to determine the kinetics of dexamethasone-mediated changes in gp52 cell surface expression. results indicated increases in gp52 csa within 4 h of dexamethasone treatment and maximal levels of antigen expression ... | 1981 | 6271704 |
| glucocorticoids regulate expression of dihydrofolate reductase cdna in mouse mammary tumour virus chimaeric plasmids. | fusions between the mouse mammary tumour virus long terminal repeat and a mouse dihydrofolate reductase cdna have been constructed in a sv40 vector. when these plasmids are transferred into recipient cells, the production of dihydrofolate reductase is regulated by glucocorticoid hormones. these results define a hormonally responsive region of the viral genome. | 1981 | 6272123 |
| activation of related transforming genes in mouse and human mammary carcinomas. | high molecular weight dnas of five tumors induced by mouse mammary tumor virus (mmtv), two mouse mammary tumors induced by a chemical carcinogen, and one human mammary tumor cell line (mcf-7) were assayed for the presence of transmissible activated transforming genes by transfection of nih 3t3 mouse cells. dnas of all five mmtv-induced tumors, one chemical carcinogen-induced tumor, and the human tumor cell line induced transformation with high efficiencies (approximately 0.2 transformant per mic ... | 1981 | 6272293 |
| absence of antigens related to murine mammary tumour virus polypeptides in rat mammary tumours. | 1981 | 6273175 | |
| age- and sex-related differences in antibody formation and blastogenic responsiveness of splenocytes from riii mice developing virus-induced mammary adenocarcinoma. | inbred riii mice, known to be infected neonatally with murine mammary tumor virus so that females develop mammary adenocarcinoma by 12-15 months of age, were examined with regard to antisheep red blood cell antibody responses at the cellular level. female mice, 3-11 months old, compared to male mice of the same ages had consistent and significant depression of the antibody response of their splenocytes. furthermore, female mice with adenocarcinoma showed an even greater depression of the antibod ... | 1981 | 6273637 |
| the endogenous proviral mouse mammary tumor virus genes of the gr mouse are not identical and only one corresponds to the exogenous virus. | the endogenous proviral copies of mouse mammary tumor virus (mmtv) were selected from a gene library of gr mouse dna. we obtained five different lambda. mmtv recombinant clones. four of them correspond to the 3' eco ri fragments of the endogenous proviruses an one comprises an intact mmtv provirus with 2 to 3 kb of flanking mouse genomic dna. heteroduplex formation followed by s1 digestion under stringent conditions shows that there is nucleotide sequence heterology among the cloned endogenous p ... | 1981 | 6273791 |
| purified glucocorticoid receptors bind selectively in vitro to a cloned dna fragment whose transcription is regulated by glucocorticoids in vivo. | activated glucocorticoid receptor protein, purified to 40-60% homogeneity from rat liver extracts, binds selectively in vitro to a cloned fragment of murine mammary tumor virus (mtv) dna. the dna fragment tested contains about half of the sequences present in intact mtv dna, and its rate of transcription, like that of the intact viral element, is strongly stimulated by glucocorticoids when it is introduced into the genome of a receptor-containing cell. in contrast, the receptor fails to bind sel ... | 1981 | 6273877 |
| is there any diagnostic relevance of human antibodies which react with mouse mammary tumor virus (mumtv)? | applying an indirect immunofluorescence assay with prolonged serum incubation on frozen-cut mouse mammary tumor slices, antibodies are detectable in human sera which react with viral inclusion bodies consisting of intracytoplasmic a particles (iap). these iap are known to represent intracellular entities of the mouse mammary tumor virus (mumtv), mainly related to mumtv core constituents. in 1,449 women studied, the antibody incidence is partially correlated with proliferating changes of the mamm ... | 1981 | 6274270 |
| synthesis of murine mammary tumor viral proteins in vitro. | the coding potential of murine mammary tumor viral genomic rna was investigated by in vitro translation of various size classes of rnas isolated from the virions. the major products of translation of full-size 35s polyadenylylated virion rna were gag-related polyproteins of 75,000, 105,000, and 180,000 daltons (p75, p105, and p180, respectively). studies on the kinetics of translation of these three proteins established that they were synthesized independently and that the smaller proteins were ... | 1981 | 6262538 |
| accelerated mammary cancer development by fetal salivary mesenchyma isografted to adult mouse mammary epithelium. | transplantation of fetal salivary mesenchyma into adult mammary glands resulted in atypical outgrowths from the mammary duct system. these duct-alveolus nodules (dan) were distinguishable from hyperplastic alveolar nodules (han) that arose from normal mammary duct systems in mice infected with murine mammary tumor virus (mumtv). dan displayed a type of ductal branching characteristic of salivary gland rather than of mammary gland, reflecting a tissue-specific perturbation of epithelium-mesenchym ... | 1981 | 6262561 |
| in vitro synthesis of polypeptides encoded by the long terminal repeat region of mouse mammary tumour virus dna. | 1981 | 6262660 | |
| sandwich enzyme immunoassay of mouse mammary tumor virus. | 1981 | 6263672 | |
| partial expression of endogenous mouse mammary tumor virus in mammary tumors induced in balb/c mice by chemical, hormonal, and physical agents. | the possible interaction of environmental factors with the endogenous mouse mammary tumor virus (mmtv) genome in the development of mammary tumors in the low-tumor-incidence balb/c mouse strain was examined. tumors were induced in virgin female animals by treatment with chemical carcinogen 7,12- dimethylbenz[alpha]anthracene or urethan, with or without prolonged hormonal stimulation, or by x-irradiation. concomitant hormonal stimulation resulted in increased tumor incidences compared with those ... | 1981 | 6264129 |
| monoclonal antibodies against antigens displayed on a progressively growing mammary tumor. | we have produced lymphocyte hybridomas between mouse myeloma cells and either spleen cells of c3h/f/c57bl/6 mice bearing the mm5mt/c1 tumor-producing murine mammary tumor virus (mmtv) or spleen cells from fisher rats inoculated with the same tumor. two classes of hybridoma-secreted monoclonal antibodies were obtained. in the first class are ivc11, iiia1, and ve7, each of which precipitated a 52,000-dalton protein from 125i-labeled purified preparations of mmtv and [3h]glucosamine-labeled mm5mt/c ... | 1981 | 6264447 |
| hormone-responsive expression of an endogenous proviral gene of mouse mammary tumor virus after molecular cloning and gene transfer into cultured cells. | a recombinant lambda phage containing mouse mammary tumor virus (mmtv) proviral dna was isolated from a gene library constructed from gr mouse liver dna. restriction enzyme analyses reveal that the cloned molecule contains a copy of one of the gr endogenous mmtv proviruses flanked on both sides by 2--3 kb of mouse genomic dna. in this report we have examined the expression of the cloned mmtv provirus after cotransfection with the herpes thymidine kinase (tk; atp:thymidine 5'-phosphotransferase,, ... | 1981 | 6264458 |
| antibodies reactive with murine mammary tumor virus in sera of patients with breast cancer: geographic and family studies. | sera of patients with breast cancer, of healthy women from the united states, east india, east africa, and china, and of healthy women of american and parsi families in which breast cancer occurred in several family members were assayed for levels of antibody reactive with the murine mammary tumor virus (mumtv) by an enzyme-linked immunosorbent assay. increased levels of antibody to mumtv (absorbance greater than or equal to 0.4) were found in sera of 18.6% of american patients with breast cance ... | 1981 | 6264479 |
| viral epitopes and monoclonal antibodies: isolation of blocking antibodies that inhibit virus neutralization. | the inability of pathogenic animal viruses to be completely neutralized by antibodies can lead to chronic viral infections in which infectious virus persists even in the presence of excess neutralizing antibody. a mechanism that results in this nonneutralized fraction of virus was defined by the topographical relationships of viral epitopes identified with monoclonal antibodies wherein monoclonal antibodies bind to virus and sterically block the binding of neutralizing antibodies. | 1981 | 6264601 |
| restriction endonuclease studies of hyperplastic outgrowth lines from balb/cfc3h mouse hyperplastic mammary nodules. | the dna's isolated from five mouse hyperplastic mammary gland outgrowth lines from balb/cfc3h mice were digested with the restriction endonucleases psti, bamhi, or ecori; electrophoresed; and analyzed by southern blotting and autoradiography. proviral dna sequences from the acquired c3h mouse mammary tumor virus were detected in the dna of all five lines, indicating that they were infected. the dna of the five hyperplastic lines contained more ecori and bamhi mouse mammary tumor virus proviral d ... | 1981 | 6265073 |