Publications

glucocorticoid regulation of protein processing and compartmentalization.		1982	6292722
natural and induced immunity to mouse mammary tumors and the mammary tumor virus (mumtv).		1982	6293110
cloned endogenous mouse mammary tumor virus dna is biologically active in transfected mouse cells and its expression is stimulated by glucocorticoid hormones.		1982	6293178
development of a mouse mammary tumor virus-negative mouse strain: a new system for the study of mammary carcinogenesis.	all inbred strains of mice transmit one or more copies of mouse mammary tumor virus (mmtv) dna integrated as proviral sequences. this complicates efforts to define viral-induced mammary carcinogenesis. here we report the use of surgical nonlethal splenectomy in tissue typing mice and the development of an mmtv-negative mouse strain. the mmtv-negative strain allows study of the involvement of non-mmtv genes in mammary carcinogenesis. in addition, it can be used as a sterile background into which ...	1982	6294336
mammary tumors in balb/cfc3h and balb/cfriii virgin female mice bearing hypophyseal isografts.	the behavior and morphology of mouse mammary tumors in high cancer strain mice are controlled by the causative murine mammary tumor viruses (mumtv). however, relationships also exist between mammary tumors and other factors such as host genotype, other etiologic agents (chemicals, x-rays), and hormones. among the latter, prolactin has been particularly studied. the aim of this investigation was to test whether the mammary tumor morphology controlled by c3h and riii mumtvs is in any way influence ...	1982	6294936
prostaglandin regulation of murine mammary tumor virus production: a basis for some of the glucocorticoid and prolactin actions on mammary tumor cell cultures.	hormonal regulation of mouse mammary tumor virus (mumtv) production has been studied in cell cultures derived from mammary carcinomas of gr mice. the purpose of this study was to define the role of prolactin in dexamethasone-induced mumtv production and to evaluate the mechanism(s) of action of these hormones. results of our investigations in vitro establish a central role for prostaglandins, in particular pgf2 alpha. prolactin treatment up to 1000 ng/ml increased the mumtv production only sligh ...	1982	6296884
interaction between host and viral genomes in mouse mammary tumors.		1982	6297374
kinetics of the reactivity of subpopulations of spleen cells of mice bearing virus-induced mammary tumors to syngeneic antigenic extracts in vitro. supportive and suppressive effects of macrophages.	this study was designed to investigate the nature of lymphocyte reactivity to soluble tumor antigens with respect to the kinetics of the reactivity, the responding cell type, and the role of accessory cells, within a syngeneic system. balb/c mice were inoculated with 1 x 10(6) viable cells of syngeneic mtv-induced mammary tumors. assessment of proliferative activity of spleen cells of these animals by dna synthesis (3h-thymidine incorporation in vitro) indicated a biphasic response to stimulatio ...	1982	6297714
many tumors induced by the mouse mammary tumor virus contain a provirus integrated in the same region of the host genome.	we have asked whether oncogenesis by the mouse mammary tumor virus (mmtv), a slowly oncogenic retrovirus, involves integration of viral dna within a certain region of the host genome. we first identified a c3h mouse mammary tumor bearing a single new mmtv provirus and cloned a 19 kilobase (kb) dna restriction fragment containing a junction of viral and host sequences. host sequences from this clone were used to retrieve 25 kb of the uninterrupted locus (termed mmtv int1) from a bacteriophage lib ...	1982	6297757
specific binding of the glucocorticoid-receptor complex to the mouse mammary tumor proviral promoter region.	to elucidate the molecular mechanism by which steroid hormones exert their regulatory function, we investigated the interaction of a glucocorticoid-receptor complex with purified dna fragments from cloned mouse mammary tumor (mmtv) proviral dna. with a dna-cellulose binding assay, rat and mouse glucocorticoid receptors were found to interact with a high affinity site or sites in or near the promoter region of the mmtv proviral dna. the assay allowed the use of unpurified as well as purified rece ...	1982	6297768
delimitation of a dna sequence which confers inducibility by glucocorticoid hormones.	a chimeric long terminal repeat-thymidine kinase (ltr-tk) gene has been used to define the sequence requirements for glucocorticoid induction of gene expression. the original ltr-tk gene contains an entire mouse mammary tumor virus (mmtv) ltr preceding the tk gene. this gene can be expressed in a hormone-responsive fashion upon transfection into l tk--cells to produce a chimeric ltr-tk mrna. stepwise deletion of nucleotide sequences 5' of the viral rna initiation site revealed that 202 nucleotid ...	1982	6306020
structural & immunological characteristics of murine mammary tumour virus of strain icrc from primary tumour cell cultures.		1982	6307861
[is the regulation of the expression of mmtv proviruses in various cell types linked to glucocorticoid receptors and/or the structure of chromatin?].	the expression of the mouse mammary tumor virus (mmtv) was studied in undifferentiated embryonal carcinoma cells (ec), in partially differentiated myoblasts derived from ec cells and in fully differentiated myotubes. whereas no mmtv rna could be detected in ec cells, relatively large amounts of tumor virus rna were found in myoblasts. the mmtv rna level was reduced in myotubes derived from myoblastic differenciation. dnasei sensibility of mmtv dna in chromatin allows us to show conformational ch ...	1982	6303198
mammary tumor formation and hormonal control of mouse mammary tumor virus expression.		1982	6303703
the region of mouse mammary tumor virus dna containing the long terminal repeat includes a long coding sequence and signals for hormonally regulated transcription.	starting from a biologically active recombinant dna clone of exogenous unintegrated gr mouse mammary tumor virus, we have generated three subclones of psti fragments of 1.45, 1.1, and 2.0 kb in the plasmid vector pbr322. the nucleotide sequence has been determined for the clone of 1.45 kb which includes almost the complete region of the long terminal repeat (ltr) plus an adjacent stretch of unique sequence dna. a short region of the 2.0 kb clone, containing the beginning of the ltr, has also bee ...	1982	6325151
glucocorticoid receptors recognize dna sequences in and around murine mammary tumour virus dna.	in several rodent cell lines, glucocorticoids increase the transcription of murine mammary tumour virus (mmtv) proviral dna in a process mediated by the glucocorticoid receptor. to investigate whether a direct interaction between the receptor and specific sequences on the induced genes can be implicated in the hormonal regulation of transcription, filter binding studies were performed with partially purified glucocorticoid receptor of rat liver and eight cloned mmtv proviral probes. both the 40 ...	1982	6327283
effect of thyroid status on development of spontaneous mammary tumors in primiparous c3h mice.	development of mammary tumors in primiparous c3h/hen mice (mouse mammary tumor virus positive) in various thyroid states was followed for one year after removal of pups. animals were either euthyroid or made hyperthyroid (by ingestion of thyroxine) or hypothyroid (by ingestion of 2-thiouracil) during involution. these manipulations resulted in significant changes in serum 3,5,3'-triiodo-l-thyronine and thyroxine levels without significant alterations in serum prolactin levels. at the end of one ...	1982	7127296
glucocorticoid regulation of mouse mammary tumor virus: identification of a short essential dna region.	transcription of mouse mammary tumor virus (mmtv) dna is stimulated by steroid hormones. to determine the dna sequences involved in this regulation, we constructed a plasmid containing the mmtv long terminal repeat (ltr) in front of the coding region of the herpes simplex thymidine kinase gene, from which the promoter had been removed. portions of the ltr were removed by the nuclease ba/31, and the deleted molecules were recloned and tested for transcriptional activity in transfections of ltk-ap ...	1983	10872340
sequence and expression of the mouse mammary tumour virus env gene.	we have determined the dna sequence of the envelope gene region of the gr strain of mouse mammary tumour virus. the sequence extends for 3012 nucleotides from the single ecori site to beyond the psti site in the 3' long terminal repeat (ltr) of the provirus. there is a major open reading frame from nucleotides 752 to 2818 which encompasses the entire env gene. this reading frame extends through a polypurine tract and into the ltr. there is another open reading frame from the first nucleotide to ...	1983	11894899
comparison of mammary tumor development in mice bearing pituitary implants & carrying mammary tumor virus infections by various routes.		1983	6325333
[introduction of foreign genes into eukaryotic cells using retrovirus as a vector].		1983	6324284
[studies on cellular differentiation by gene transfer].		1983	6324287
multiple genetic factors in the mhc and predominant role of d-end in the resistance against c3h-mtv-induced mammary tumors.		1983	6324428
the role of protein glycosylation in the compartmentalization and processing of mouse mammary tumor virus glycoproteins in mouse mammary tumor virus-infected rat hepatoma cells.	the relationship of protein glycosylation to compartmentalization and processing of mouse mammary tumor virus (mtv) glycoproteins has been examined in m1.54, a cloned line of mtv-infected rat hepatoma tissue culture cells. previous work established that full maturation of mtv glycoproteins in this cell line requires dexamethasone, a synthetic glucocorticoid (firestone, g. l., payvar, f., and yamamoto, k. r. (1982) nature (lond.) 300, 221-225). the ability to regulate production of the full compl ...	1983	6304028
regulation of endogenous murine mammary tumor virus expression in c57bl mouse lactating mammary glands: transcription of functional mrna with a block at the translational level.	expression of endogenous murine mammary tumor viruses (mumtvs) in various mouse strains is regulated in different ways, and in the absence of exogenous mumtv, this regulation influences the incidence of spontaneous mammary tumors. two mouse strains with low mammary tumor incidence, balb/c and c57bl, control endogenous mumtv expression at different stages. neither of the strains had any detectable mumtv polypeptides in its lactating mammary glands (lmg). however, in c57bl lmg, substantial amounts ...	1983	6304344
glucocorticoids and chromosomal position modulate murine mammary tumor virus transcription by affecting efficiency of promoter utilization.	the rate of transcription of murine mammary tumor virus (mtv) sequences in mtv-infected rat hepatoma tissue culture cells is strongly affected by both glucocorticoid hormones and the chromosomal position of provirus integration. we have characterized mtv rnas produced in j2.17 and m1.54, independent isolates containing, respectively, 1 and 10 proviruses integrated at distinct chromosomal loci. m1.54, but not j2.17, synthesized mtv rna in the absence of glucocorticoids; the rate of hormone-stimul ...	1983	6304497
androgen regulation of cell proliferation and expression of viral sequences in mouse mammary tumour cells.	the role of steroids in promoting cell proliferation is well established but the molecular mechanisms are not clear. the s115 mouse mammary tumour cell line provides a model system for molecular studies in vitro in that it exhibits in tissue culture both a positive proliferative response to androgens and a change from a transformed phenotype in the presence of androgen to a normal phenotype when androgen is removed. we have considered here the possible involvement of mouse mammary tumour virus ( ...	1983	6304523
subfragments of the large terminal repeat cause glucocorticoid-responsive expression of mouse mammary tumor virus and of an adjacent gene.	after transfection of mouse mammary tumor virus (mmtv) proviral dna into cultured cells, the dna is transcribed in a glucocorticoid-sensitive fashion. the large terminal repeat (ltr) region of mmtv is 1,328 nucleotides long and contains the regulatory information necessary for the hormonal response. we have constructed a mmtv ltr-thymidine kinase (tk) chimeric gene and have tested the biological activity of molecules containing various deletions in the ltr after transformation of ltk- aprt- mous ...	1983	6304728
serum antibodies against mouse mammary tumor-virus-associated antigen detected nine months before appearance of a breast carcinoma.		1983	6305248
isozyme phenotypes of polyoma virus tumors in mice.	isozyme profiles for 32 enzyme systems were studied in tumors induced by two strains of polyoma virus (2pta and lid1), in two conventional mouse strains (c3h/bida and nih), and in athymic (nude) mice of two genetic backgrounds (c3h/hes nu/nu and nih nu/nu). tumors studied were: primary and transplant passages of salivary gland tumors (127); primary thymic epithelial tumors (12); primary subcutaneous sarcomas (6); primary hair follicle tumors (5); primary and transplant passages of mammary tumors ...	1983	6305495
tumorigenesis by mouse mammary tumor virus: evidence for a common region for provirus integration in mammary tumors.	we have prepared specific probes for unique-sequence cellular dna adjacent to each of the newly integrated proviruses in tumors induced by mouse mammary tumor virus (mmtv). the use of such probes to screen a large number of independent mammary tumors in the br6 strain of mouse has indicated that in at least 17 out of the 40 tumors examined so far, an mmtv provirus has integrated into a common chromosomal domain. a 10 kb eco ri fragment of single copy dna from this region has been isolated and pa ...	1983	6305506
biological activity of cloned mammary tumor virus dna fragments that bind purified glucocorticoid receptor protein in vitro.		1983	6305596
transcription initiation of transfected mouse mammary tumor virus ltr dna is regulated by glucocorticoid hormones.	a chimeric gene, recombined in vitro, containing a long terminal repeat (ltr) sequence from the proviral dna of mouse mammary tumor virus and the thymidine kinase (tk) gene of herpes simplex virus was introduced into l tk- cells. no transcription of ltr rna was observed in transfected cells when glucocorticoid hormones were absent from the growth medium. accumulation of ltr initiated rna was measured upon hormone addition by the single strand specific nuclease rna mapping procedure. the accumula ...	1983	6308557
tissue and organ distribution of mammary tumor virus antigens in low and high mammary cancer strain mice.	expression of mammary tumor virus (mtv) antigen was measured in a wide variety of organs and tissues of a series of high (gr, shn, shnf, dd, sln, slnf) and low (ddf, ddd, dddf, kf, kff, ddy, c57bl, balb/c) mammary cancer strain mice. tests were carried out by microimmunodiffusion (micro-id) and immunoperoxidase tests on formalin-fixed tissues and radioimmunoassays in extracts for 2 viral proteins, mtvp27 from the viral core and mtvgp52 from the viral envelope. organs with exocrine function, i.e. ...	1983	6309527
proliferative responses of mouse mammary glands to 17 beta-estradiol and progesterone and modification by mouse mammary tumor virus.	the responses of mammary glands of ovariectomized mice to 17 beta-estradiol and progesterone were measured by mitotic and [3h]thymidine-labeled indices in low-tumor c57bl mice and high-tumor br6 mice. the br6 mice were subdivided into those carrying murine mammary tumor virus (mumtv) and those that had been freed from it by foster nursing. in all groups, continuous stimulation by the two hormones administered together resulted in a cell proliferation peak. the magnitude of response varied accord ...	1983	6317935
glucocorticoid regulation of transcription at an amplified, episomal promoter.	the mouse mammary tumor virus long terminal repeat (mmtv ltr) has been introduced into cultured murine cells, using the 69% transforming fragment of bovine papilloma virus type 1 (bpv). transformed cells contain up to 200 copies of the chimeric molecules per diploid genome. the restriction endonuclease map of the acquired recombinants, as well as the physical structure of the dna, indicates that the ltr-bpv molecules present in these cells occur exclusively as unintegrated, extrachromosomal epis ...	1983	6318079
mouse mammary tumour virus related sequences are present in human dna.	mumtv-related sequences have been identified in the dna of human breast cancer cells using the southern transfer technique and hybridisation with cloned mumtv dna under conditions in which partially mismatched sequences form stable hybrids. hybridisation with cloned fragments of the mumtv genome showed that the gag-pol region shares the most homology (estimated to be greater than 80%) with the human mumtv-related sequences, however, dna fragments partially homologous to the mumtv ltr, gag ad env ...	1983	6306576
[hormone-dependent enhancement of malignant phenotype in cells infected with mouse mammary tumor virus (mmtv), and role of antigen transduction in this process].	mouse mammary tumor virus (mmtv) is known to infect heterologous cells but it does not appear that it alters their growth or morphological characteristics. djungarian hamster mammary tumor cells infected with mmtv were found to increase the ability of the above cells to grow in semi-solid media. this effect was demonstrable only in the presence of insulin and dexamethasone in cultural media. meanwhile non-infected cells were discovered to show no responsiveness to hormones. the expression of non ...	1983	6307426
among the human antibodies reacting with intracytoplasmic a particles of mouse mammary tumor virus, some react with mmtv p14, the nucleic-acid-binding protein, and others with mmtv p28, the main core protein.	human igg antibodies reacting in the indirect immunofluorescence test with clusters of intracytoplasmic a particles in mouse tissues were analyzed by means of both radioimmunoprecipitation and enzyme-linked immunoabsorbant assays. generally, antibody-containing sera reacted with epitopes of p14, the nucleic-acid-binding core protein of mouse mammary tumor virus, corresponding to the protein ap14 of intracytoplasmic a particles. comparatively few sera reacted with epitopes of the main core protei ...	1983	6305853
correlation of glucocorticoid receptor binding sites on mmtv proviral dna with hormone inducible transcription.	steroid hormones, when complexed to their receptors, recognize and bind specific dna sequences and subsequently induce increased levels of transcription. the mechanisms of steroid hormone action were analyzed by constructing chimeric dna molecules from portions of mouse mammary tumor virus envelope and long terminal repeat (ltr) regions ligated to the thymidine kinase (tk) gene of herpes simplex virus. this construction allowed the tk gene to be expressed in a hormone-responsive fashion upon tra ...	1983	6318311
effect of malignant transformation upon the cellular retinoid binding proteins in cultured murine mammary cells.	cellular retinol (crbp) and retinoic acid binding proteins (crabp) were measured in normal (c57bl) and murine mammary tumor virus (mumtv)-induced murine mammary tumor cells (c57blfriii) grown in monolayer culture. high speed supernatant fractions (cytosols) from transformed cells contained elevated levels of crbp and crabp (0.276 and 1.410 pmol/mg protein, respectively) compared to cytosol from non-transformed murine mammary cells which contained only low levels of crbp (0.099 pmol/mg protein). ...	1983	6318967
peroral infection of suckling mice with milk-borne mouse mammary tumour virus: uptake of the main viral antigens by the gut.	persistence of mouse mammary tumour virus (mmtv) components in the digestive tract of suckling mice was investigated by immunoperoxidase staining of the main viral antigens and micro-immunoenzyme assays of gp52 and p28; these latter assays were also performed after ingestion of milk enriched in viral antigens using cr2o3 as a marker for the alimentary bolus migration. when compared to the ingested antigens, the amounts of gp52 and p28 decreased during transit, p28 being more rapidly digested tha ...	1983	6319548
expression of a viral oncogene under control of the mouse mammary tumor virus promoter: a new system for the study of glucocorticoid regulation.		1983	6320286
increased level of immunoreactive enkephalins in the brain of tumor-bearing mouse.	balb/c mice with emt6-ky mouse mammary tumor were assayed for the immunoreactive content of enkephalins in the brain by radioimmunoassay. brains of tumor-bearing mice had approximately 22 percent more immunoreactive enkephalins than those of the controls.	1983	6320320
effect of hormones on the expression of proviral genes mtv-2 and mtv-3 in mouse mammary gland.	we have investigated the expression of the mtv-2 and mtv-3 proviral genes in mouse mammary glands by examining the effect of hormones on levels of mammary tumor virus (mtv) proteins p27 (gag) and gp52 (env) in mouse mammary explants. we also investigated the effect of the hormones on dna synthesis in the explants. the mammary glands were derived from inbred gr and 020 mice, and from the respective congenic mouse strains gr/mtv-2- and 020/mtv-2+. the addition of insulin to the culture medium caus ...	1983	6298127
region-specific initiation of mouse mammary tumor virus rna synthesis by endogenous rna polymerase ii in preparations of cell nuclei.	adenosine 5'-o-(2-thiotriphosphate) (atp beta s) and guanosine 5'-o-(2-thiotriphosphate) (gtp beta s) were used to demonstrate initiation of mouse mammary tumor virus (mmtv) rna in preparations of whole nuclei from control and glucocorticoid-treated mmtv-infected rat hepatoma tissue culture cells. rna chains initiated in the cell-free reaction retain a thiol group at the 5' end and can be separated from thiol-free rna chains by chromatography on mercury-sepharose. the abundance of mmtv sequences ...	1983	6298206
the correlation between tissue differentiation and production of mammary tumor virus (mtv) in transplanted murine mammary tumors. electron microscopic observations.	the spontaneous mammary tumors of the nmri mouse are well developed microcystic adenocarcinomas. serial isologous transplantation of the tumors results in nearly complete dedifferentiation to a solid tumor, in which only electron-microscopically rudimentary acinus-like microlumina can be observed. the adenocarcinomas produce a and b particles in abundance, with the a particles appearing intracellularly in the adluminal cytoplasmic regions of the epithelial cells in association with typical cellu ...	1983	6298246
a deletion mutant of mouse mammary tumour virus, lacking 516 nucleotides of the 5' long terminal repeat sequence, can be expressed in a hormone-responsive fashion.	in vitro manipulation of proviral dna of mouse mammary tumour virus (mmtv) was used to construct mutants with defined deletions at the 5' end of the proviral gene. in the mutants 516, 1400 and 2000 nucleotides were removed from the 5' end. the deleted proviral dna was tested for transcription and glucorticoid hormone regulation of viral rna expression upon cotransfection into rat xc tk- cells with a thymidine kinase gene. intact proviral dna contained in the plasmid vector pbr322 and the deletio ...	1983	6298347
transcription of mouse mammary tumor virus: identification of a candidate mrna for the long terminal repeat gene product.	we have examined an assortment of preneoplastic and neoplastic mouse mammary tissues for the presence of an mrna which could encode the putative long terminal repeat gene product of mouse mammary tumor virus. we report here the detection of a novel mouse mammary tumor virus-specific, polyadenylic acid-containing transcript in certain preneoplastic and neoplastic mammary tissue of balb/c mice. the molecule is 1.6 kilobases in length and contains sequences from the transcriptional leader and the u ...	1983	6298469
murine mammary tumor virus related antigen in human male mammary carcinoma.	an antigen immunologically related to mouse mammary tumor virus (mumtv) and the major envelope glycoprotein, gp52 of mumtv, was identified in tissue sections of human male and female mammary carcinomas using the peroxidase-antiperoxidase technique. the specificity of the reaction was established by absorption studies. positive reactions with the gp52 antiserum were seen in mouse and human mammary carcinomas, but not in normal mammary tissues, mammary tissues with benign diseases and in other pri ...	1983	6295611
chemical carcinogen-mouse mammary tumor virus interactions in cell transformation.	we have studied the process of mammary cell transformation in vitro using a single cell clone (clone 18) from a presumptive epithelial cell line, c57mg, derived from a normal mammary gland; a mouse mammary tumor virus (mmtv) host-range variant (riii)vp4; and the potent initiating carcinogen 7,12-dimethylbenz(a)anthracene (dmba). after several serial subcultures, cells treated with virus and then with carcinogen exhibited an altered (transformed) morphology, a dramatic increase in anchorage indep ...	1983	6295922
antibody reacting with the murine mammary tumor virus in the serum of patients with breast carcinoma: a possible serological detection method for breast carcinoma.	sera from patients with stages a and b infiltrating ductal carcinoma of the breast, benign breast disease, cancers other than breast carcinoma, and normal female controls were examined by indirect immunoelectron microscopy (iem) and a viral agglutination test for evidence of antibodies directed against murine mammary tumor virus (mmtv). sera from 41 (79%) of 52 patients with breast carcinoma and eight (19%) of 42 normal subjects or patients with benign breast disease (noncancer subjects) showed ...	1983	6291754
terminal amino acid sequences and proteolytic cleavage sites of mouse mammary tumor virus env gene products.	the mature envelope glycoproteins of mouse mammary tumor virus (gp52 and gp36) were isolated by reversed-phase high-pressure liquid chromatography. the n-terminal amino acid sequence of gp36 was determined for 28 residues. the c-terminal amino acid sequences of gp52 and gp36 were determined by carboxypeptidase digestion. the n-terminal amino acid sequence of gp52 has been reported previously (l. o. arthur et al., j. virol. 41:414-422, 1982). these data were aligned with the predicted amino acid ...	1983	6310154
a new locus (mtv-4) for endogenous mammary tumor virus expression and early mammary tumor development in the shn mouse strain.	the shn mouse strain, which has a high incidence of mammary cancer, developed by inbreeding and selection from swiss stock mice by dr. h. nagasawa and co-workers (meiji university, tokyo, japan), harbored an endogenous mammary tumor virus (mtv) responsible for a high frequency of mammary tumors early in life. the locus was called "mtv-4" and was only comparable with mtv-2 of the gr mouse strain in its inducing capacity of mammary cancer. molecular hybridization with 32p-labeled mtv complementary ...	1983	6310199
immunological selection of variant mouse lymphoid cells with altered glucocorticoid responsiveness.	we have devised an immunological procedure to separate cells on the basis of expression of mouse mammary tumor virus (mmtv) gene products. plastic petri dishes coated with specific antibodies against mmtv proteins bind cells with an efficiency that correlates with the level of mmtv gene expression. glucocorticoid-sensitive mouse thymoma cell line w7 was infected with mmtv. clones from the infected population retain the relatively slow cytolytic glucocorticoid response and, in addition, exhibit a ...	1983	6310372
enhancer elements activated by steroid hormones?		1983	6310402
the glucocorticoid receptor binds to defined nucleotide sequences near the promoter of mouse mammary tumour virus.	glucocorticoids are known to induce the transcription of integrated proviral mouse mammary tumour virus (mmtv) genes in a variety of cell lines derived from mouse mammary tumours. chimaeric genes in which selectable markers are linked to the long terminal repeat (ltr) region of mmtv can be induced by the synthetic glucocorticoid dexamethasone after introduction into mouse fibroblasts. this suggests that the regulatory elements required for hormonal induction are located within the cloned ltr fra ...	1983	6310405
a small region of the mouse mammary tumor virus long terminal repeat confers glucocorticoid hormone regulation on a linked heterologous gene.	expression of mouse mammary tumor virus (mmtv) proviruses is transcriptionally regulated by glucocorticoid hormones. we have linked the mmtv long terminal repeat (ltr) to the coding region of the herpes simplex virus thymidine kinase gene and used this construction to characterize sequences within the ltr that are involved in glucocorticoid regulation. our results show that 290 base pairs (bp) of the mmtv ltr, including 190 bp upstream from the start site for transcription, are sufficient to con ...	1983	6310597
breast cancer and mouse mammary tumor virus.		1983	6311069
sera from irradiated rats contain antibodies to a ubiquitous tumour-associated antigen.	female rats of the inbred strains bn/birij and wag/rij were irradiated with 30 kv x-rays, or 15 mev or 0.5 mev fast neutrons. sera were collected several months after irradiation and found to be negative for antibodies reacting with the murine mammary tumour virus as tested by a solid-phase radioimmunoassay and an immunofluorescence absorption test. we found, however, that in an immunofluorescence assay several sera from irradiated rats reacted with a cytoplasmic antigen in rat mammary, ureter a ...	1983	6311562
evidence for a prokaryotic promoter in the murine mammary tumor virus long terminal repeat.	the long terminal repeat (ltr) of c3h murine mammary tumor virus (mumtv) is approx. 1.3 kb long. haeiii digestion of a cloned psti fragment containing the left-end ltr generated four fragments of sizes 0.56, 0.41, 0.34 and 0.14 kb, one of which (0.41 kb) had a promoter activity in escherichia coli. this was demonstrated by replacing the bacterial promoter for the neomycin-resistance (nmr) gene in the plasmid pkc56 with the haeiii fragments. only the 0.41-kb fragment that contains sequences from ...	1983	6311680
molecular biological characterization of a highly leukaemogenic virus isolated from the mouse. iii. identity with mouse mammary tumour virus.	a highly leukaemogenic virus isolate (dmba-lv) endogenous to the cfw/d mouse has been found to contain two viral genomes. one was closely related to the type b milk-borne mouse mammary tumour virus (mmtv) and present in tenfold excess over a type c viral genome which was only partially related to xenotropic and polytropic isolates from the cfw/d mouse as well as to the ecotropic moloney murine leukaemia virus isolate. the thymic lymphoma cell line that produced dmba-lv expressed high levels of m ...	1983	6311950
sheep pulmonary adenomatosis: demonstration of a protein which cross-reacts with the major core proteins of mason-pfizer monkey virus and mouse mammary tumour virus.	a retrovirus that causes pulmonary adenomatosis, a contagious lung tumour of sheep, contains a 25 000 mol. wt. polypeptide which cross-reacts with the major core protein (p27) of mason-pfizer monkey virus and mouse mammary tumour virus.	1983	6311958
nucleotide sequencing of an apparent proviral copy of env mrna defines determinants of expression of the mouse mammary tumor virus env gene.	to extend our understanding of the organization and expression of the mouse mammary tumor virus genome, we determined the nucleotide sequence of large regions of a cloned mouse mammary tumor virus strain c3h provirus that appears to be a dna copy of env mrna. in conjunction with analysis of several additional clones of integrated and unintegrated mouse mammary tumor virus dnas, we came to the following conclusions: (i) the mrna for env is generated by splicing mechanisms that recognize conventio ...	1983	6312081
amplification and hormone-regulated expression of a mouse mammary tumor virus-eco gpt fusion plasmid in mouse 3t6 cells.	mouse 3t6 cells were transformed with a chimeric dna plasmid, psvmgpt, in which the mouse mammary tumor virus (mmtv) promoter was fused to the escherichia coli gene encoding xanthine-guanine phosphoribosyl transferase (eco gpt). the transformants exhibited glucocorticoid-inducible expression of eco gpt. with limiting xanthine concentrations, conditions were established in which cell growth became hormone dependent. cells selected for their ability to grow in limiting concentrations of both xanth ...	1983	6312292
widespread occurrence in mammals of antibodies reactive to intracytoplasmic a particles of the mouse mammary tumor virus.	serum antibodies reactive to clusters of intracytoplasmic a particles in mouse mammary tumors and leukemia cells by means of an indirect immunofluorescence assay were detected in 11 mammalian species (ranging in frequency from 5.1 to 29.3%). these antibodies could not be found in sera from chicken, ducks and geese. their presence in so many mammalian species, not only in mammary tumor virus-infected mice, sheds new light on similar antibodies in man detected 10 years ago.	1983	6312921
nucleotide sequence of the 5' noncoding region and part of the gag gene of mouse mammary tumor virus; identification of the 5' splicing site for subgenomic mrnas.	we have determined the sequence of the first 1371 nucleotides at the 5' end of the genome of mouse mammary tumor virus using molecularly cloned proviral dna of the gr virus strain. the most likely initiation codon used for the gag gene of mouse mammary tumor virus is the first one, located 312 nucleotides from the 5' end of the viral rna. the 5' splicing site for the subgenomic mrna's is located approximately 288 nucleotides downstream from the 5' end of the viral rna. from the dna sequence the ...	1983	6314267
glucocorticoid regulation of gene expression: mouse mammary tumor virus as a model system.		1983	6314448
lobuloalveolar differentiation and tumorigenesis: two separate activities of mouse mammary tumor virus.	the morphological growth of the mammary glandular tree from 3 to 18 months of age has been quantified in three groups of genetically identical virgin female mice: balb/c mice free of milk-transmitted mouse mammary tumor virus (mmtv) infection and balb/cfc3h and balb/cfriii mice carrying milk-transmitted mmtv infection of c3h or riii origin, respectively. mice were killed at 3-month intervals, and their mammary glands were prepared for stereoscopic examination as whole mounts. any cluster of alve ...	1983	6315219
molecular genetics of mouse mammary tumor virus.		1983	6315306
mouse mammary tumor virus expression and mammary tumor development.		1983	6315307
regulation of mouse mammary tumor virus gene expression by glucocorticoid hormones.		1983	6315308
unusual findings of viral production (mumtv) in murine mammary tumors (balb/cfc3h).	some unusual findings of the murine mammary tumor virus (mumtv) are described in cells of balb/cfc3h mice mammary tumors: (1) a conspicuous endocellular production of b particles by budding of a particles into small and large cytoplasmic vacuoles, into intracytoplasmic lumina, and possibly into vacuoles of secretion; (2) an extracellular production of b particles (in addition to the classic budding via microvilli) by opening at the cell surface of intracytoplasmic lumina containing mature and im ...	1983	6315481
the proviral dna of mouse mammary tumor virus: its use in the study of the molecular details of steroid hormone action.		1983	6315504
alterations of acquired mouse mammary tumor virus dna during mammary tumorigenesis in balb/cfc3h mice.	the patterns of the milk-transmitted (exogenous) mouse mammary tumor virus (mumtv) dna restriction endonuclease fragments in the nodule and tumor stages of balb/cfc3h mouse mammary neoplasia were compared with the use of the southern blot analysis. acquired mumtv restriction fragments were detected in dna from hyperplastic alveolar nodules (han), from primary hyperplastic outgrowths (hpo), from families of transplanted hpo, from tumors from hpo, and from serially transplanted tumors. the restric ...	1983	6316008
sequence-specific binding of glucocorticoid receptor to mtv dna at sites within and upstream of the transcribed region.	glucocorticoid receptor protein stimulates transcription initiation within murine mammary tumor virus (mtv) dna sequences in vivo, and interacts selectively with mtv dna in vitro. we mapped and compared five regions of mtv dna that are bound specifically by purified receptor; one resides upstream of the transcription start site, and the others are distributed within transcribed sequences between 4 and 8 kb from the initiation site. each region contains at least two strong binding sites for recep ...	1983	6317184
anti-glucocorticoids block the enhancement of mouse mammary tumor virus production by 12-o-tetradecanoylphorbol-13-acetate.	four anti-glucocorticoids, 11-deoxycortisol, deoxycorticosterone, 17 alpha-methyltestosterone and progesterone were demonstrated to antagonize the stimulation of mouse mammary tumor virus (mmtv) production by the glucocorticoid hormone dexamethasone in the cell line mm5mt. these same anti-glucocorticoids were also able to suppress the enhancement of mmtv production by the tumor promoting phorbol ester, 12-o-tetradecanoylphorbol-13-acetate (tpa), whereas estradiol, the anti-tumor promoter trans-r ...	1983	6317217
adp-ribosylation of chromosomal proteins and mouse mammary tumor virus gene expression. glucocorticoids rapidly decrease endogenous adp-ribosylation of nonhistone high mobility group 14 and 17 proteins.	the relationship between endogenous adp-ribosylation of chromosomal proteins and glucocorticoid-regulated mouse mammary tumor virus gene expression was investigated in cultured mouse mammary tumor cells. it was observed that glucocorticoids quickly decreased endogenous (adp-ribose)n on the nonhistone high mobility group (hmg) 14 and 17 proteins. the half-time for this loss was 8 and 17 min, respectively, for the two proteins. (adp-ribose)n on hmg 1 and 2 and on histone h1 was less susceptible to ...	1983	6317693
leukocyte migration inhibition responses to mcf-7, murine mammary tumor virus, and thomsen-friedenreich antigen in a series of cancer patients.		1983	6299532
demethylation and expression of murine mammary tumor proviruses in mouse thymoma cell lines.	murine mammary tumor virus (mmtv) expression is analyzed in a t-lymphoid cell line (t1m1) sensitive to the killing effect of glucocorticoids and in two of its variants, one resistant (t1m1r) and one supersensitive (t1m1ss) to glucocorticoid-induced lymphocytolysis. in the t1m1 line, mmtv is expressed and induced approximately 10-fold by short treatment with dexamethasone. southern blot analyses of restriction enzyme digests of dna from t1m1 cells reveal three proviruses similar to those of norma ...	1983	6296860
integration of new endogenous mouse mammary tumor virus proviral dna at common sites in the dna of mammary tumors of c3hf mice and hypomethylation of the endogenous mouse mammary tumor virus proviral dna in c3hf mammary tumors and spleens.	to understand the molecular mechanisms by which the endogenous murine mammary tumor virus (mumtv) proviruses are expressed and produce late-occurring mammary tumors in c3hf mice, we analyzed, by the use of restriction enzymes and the southern transfer procedure, genomic dna from normal organs of mammary tumor-bearing and tumor-free mice and from 12 late-occurring c3hf mammary tumors. we found, by using the restriction enzymes ecori and hindiii, that in addition to the preexisting endogenous mumt ...	1983	6296426
identification of a cellular receptor for mouse mammary tumor virus and mapping of its gene to chromosome 16.	pseudotypes of vesicular stomatitis virus (vsv) containing envelope glycoproteins provided by c3h mammary tumor virus (mtv) instead of the normal vsv g-proteins were prepared and used to assay the presence of an mtv receptor on cells. the assay was specific as demonstrated by competition studies with excess mtv particles and neutralization of the pseudotypes with anti-mtv serum or monoclonal antibodies directed against mtv gp52. the mtv receptor was abundantly present on mouse cells but hardly d ...	1983	6296428
cloned mouse mammary tumor virus dna exhibits glucocorticoid-dependent expression in simian virus 40-transformed mink cells.	mink lung epithelial cells were transfected with two cloned mouse mammary tumor virus (mmtv) dnas, a 9-kilobase clone derived from an unintegrated exogenous viral genome and a 14-kilobase clone containing an integrated endogenous provirus along with cellular flanking sequences. mink lung cells were chosen because they do not contain endogenous mmtv sequences. on the basis of our observation that simian virus 40 dna efficiently transforms these cells, we isolated cell clones containing mmtv dna b ...	1983	6296429
quantitative analysis of mouse mammary tumor virus in milk in two sublines of riii/anok mice with low and high mammary tumor incidence.	mammary tumors have ceased to develop in descendants of one female of the riii/anok mouse strain which was brought from the mouse colony of okayama university medical school in 1975, while descendants of another female of this strain have maintained a high tumor incidence. the former and latter descendants were separated out as riii/anok/2 and riii/anok/1 sublines, respectively. the amount of mouse mammary tumor virus (mmtv) in the milk of individual females in these two sublines was determined ...	1983	6301918
expression and regulation of escherichia coli lacz gene fusions in mammalian cells.	gene fusions between the escherichia coli lacz gene and dna segments containing the simian virus 40 early promoter or the mouse mammary tumor virus (mmtv) promoter direct the synthesis of functional beta-galactosidase in cos 7 monkey cells and mouse ltk-cells. enzymatic activity was measured either 72 h after transfection or in stable transformants. the sensitive beta-galactosidase assay was used to measure gene expression and to optimize the efficiency of dna-mediated transfection. glucocortico ...	1983	6302193
in vivo modification of retroviral gag gene-encoded polyproteins by myristic acid.	it has recently been shown by mass spectral analysis (henderson et al., proc. natl. acad. sci. u.s.a. 80:339-343, 1983) that the p15gag protein of murine leukemia viruses contains a novel post-translational modification, an amino-terminal myristyl (tetradecanoyl) amide. in this report we show that p15gag is the only structural protein to contain this fatty acid. in addition, the gag precursor polyproteins of type b, c, and d retroviruses have been examined for the presence of myristic acid by me ...	1983	6302307
expression and disposition of the murine mammary tumor virus (mumtv) envelope gene products by murine mammary tumor cells.	three murine mammary tumor virus (mumtv)-producing epithelial cell lines derived from murine mammary tumors were examined in order to identify the mumtv-specific cell surface antigens and their distribution on the cell surface, to study the kinetics of the mumtv envelope precursor processing, virus assembly, and release, and to characterize the soluble mumtv antigens that are shed into culture medium. cell surface labeling experiments showed that only the mature mumtv envelope glycoproteins gp52 ...	1983	6302986
an antigen cross-reactive with gp52 of mammary tumor virus is expressed on a b cell subpopulation of mice.	the reactivity of murine lymphoid tissue with biotinylated f(ab')2 fragments of monoclonal antibody ve7 (biot ve7), which reacts with gp52 of murine mammary tumor virus (mumtv), was tested with fluoresceinated avidin in an indirect fluorescent antibody assay on live splenocytes. a small percentage of splenic lymphocytes in c3h/he mice infected exogenously with mumtv, and in c57bl/6 mice that, like c3h/he, harbor several endogenous mumtv proviruses in their genomes, were reactive with the monoclo ...	1983	6300244
further evidence for the protein coding potential of the mouse mammary tumor virus long terminal repeat: nucleotide sequence of an endogenous proviral long terminal repeat.	the 3' half of an endogenous mouse mammary tumor virus from a c3h mouse was cloned in the charon 4a vector phage. a comparison of the proviral clone with previously published endogenous mouse mammary tumor virus restriction maps identified it as endogenous unit ii (j. cohen and h. varmus, nature [london] 278:418-423, 1979), which is present in all inbred mouse strains derived from the original bagg albino x dba cross. the nucleotide sequence of the unit ii long terminal redundancy (ltr) was dete ...	1983	6300464
atmospheric pressure effects on tumor growth: hypobaric anoxia and growth of a murine transplantable tumor.	inasmuch as solid tumor growth and some intervention methods for tumor control have often been related to the low oxygen levels in tumor tissue, and a special role for hypoxia, perhaps even in oncogenesis, has been suggested by observations of unexpectedly low tumor incidence in mice caged a lifetime in the environment of a simulated altitude, inbred c3h/hen mammary tumor virus-positive mice bearing transplanted tumors (16/c murine mammary adenocarcinoma) were exposed to atmospheric pressure var ...	1983	6300503
two classes of mutant mammary tumor virus-infected htc cell with defects in glucocorticoid-regulated gene expression.	we have isolated mutant derivatives of m1.54 (a mammary tumor virus [mtv]-infected rat hepatoma [htc] cell line containing multiple integrated proviruses) that fail to express hormone-inducible cell surface viral glycoproteins. in wild-type m1.54, the synthetic glucocorticoid dexamethasone selectively stimulates the rate of synthesis of mtv rna. in addition, dexamethasone is essential for posttranslational maturation of three of the four cell surface viral glycoproteins processed from the mtv gl ...	1983	6300655
analysis of glucocorticoid-inducible genes in wild-type and variant rat hepatoma cells.	we present pharmacological and genetic evidence that regulation of different genes by glucocorticoid hormones in the rat hepatoma cell line, htc, occurs in a coordinate manner. we have analyzed the responses of four different glucocorticoid-inducible proteins, tyrosine aminotransferase [l-tyrosine:2-oxoglutarate aminotransferase (ec 2.6.1.5)], glutamine synthetase [l-glutamate:ammonia ligase (ec 6.3.1.2)], a secreted glycoprotein belt i, and the mouse mammary tumor virus (mmtv)-encoded protein ( ...	1983	6135149
induction of the acute-phase reactant, alpha 1-acid glycoprotein, by glucocorticoids in rat hepatoma cells.	alpha 1-acid glycoprotein (alpha 1-agp), or orosomucoid, is shown to be inducible by glucocorticoids in htc rat hepatoma cells. immunoprecipitation of [35s]methionine pulse-labeled proteins from these cells reveals secreted proteins of mr = 35,000-48,000 (alpha 1-agp) and mr greater than 180,000, both of which are greatly enhanced by glucocorticoid treatment. the amount of alpha 1-agp-specific mrna in htc cells is greatly increased (at least 100-fold) in response to glucocorticoids. the new stea ...	1983	6139269
effects of insulin, dexamethasone and phorbol ester on virus production in cultivated dba/2 mouse leukemia (mla) cells.	the in vitro production of intracytoplasmic oncovirus a-particles and of atypical mammary tumor virus (mlav) from a line of dba/2 mouse leukemia (mla) cells were compared in the presence of insulin, dexamethasone and 12-0-tetradecanoyl-phorbol-13-acetate (tpa), which are known to stimulate the synthesis of mouse mammary tumor virus. high amounts of a-particles were recovered from cells cultivated in the presence of dexamethasone (1 microgram/ml) as compared to untreated controls; in contrast, th ...	1983	6140829
monoclonal antibodies to three epitopic regions of feline leukemia virus p27 and their use in enzyme-linked immunosorbent assay of p27.	three different monoclonal antibodies were developed against the major core protein (p27) of feline leukemia virus (felv). each antibody was directed against a different epitope of the species-specific portion of felv-p27. the 3 antibodies reacted with 5 different isolates of felv but not with 7 other retroviruses (mulv (rauscher), mulv (akr), mpmv, mmtv, smrv, baev, rd 114). these monoclonal antibodies could readily be adapted to an enzyme-linked immunosorbent assay (elisa) for the specific mea ...	1983	6186744
strain-specific determinants on the major phosphoprotein of murine mammary tumor viruses.	the major phosphoprotein (p23) of murine mammary tumor virus (mumtv) was purified for c3h virus, using a combination of alkyl agarose chromatography and gel filtration. monospecific antiserum was raised against glutaraldehyde crosslinked polymers of purified p23, and the antiserum was then used with iodinated p23 to develop a competition radioimmunoassay. phosphoprotein p23 was shown to contain both group- and type-specific antigenic determinants in assays using detergent-disrupted virions of mu ...	1983	6187126
structural analysis of a 1.7-kilobase mouse mammary tumor virus-specific rna.	we have detected a mouse mammary tumor virus (mmtv)-specific 1.7-kilobase (kb) polyadenylated rna in mammary glands of several mouse strains. in balb/c mice, it is the only mmtv-specific rna species present. c3h and gr mammary glands and tumors contain, in addition, 3.8- and 7.8-kb mmtv rnas. nuclease s1 analysis was performed to map 1.7-kb polyadenylated rna. it contains predominantly long terminal repeat (ltr) sequences. the 5' end maps approximately 134 nucleotides upstream from the 3' end of ...	1983	6188860
decrease in mammary tumour incidence in virgin c3h mice given interferon only while suckling.	a high proportion of females of the c3h strain of mice develop tumours of the mammary gland which are caused by mouse mammary tumour virus (mmtv) transmitted through the milk. we have examined whether administration of mouse interferon (ifn) to nursing mothers and/or their suckling offspring only during the period of nursing, can affect the incidence of tumours developing in these animals. in two separate experiments, animals receiving ifn by direct injection while suckling, and remaining virgin ...	1983	6190493
proteins encoded by mouse mammary tumour virus.		1983	6196157
a viral coat glycoprotein (gp52mumtv) has detergent-sensitive and detergent-resistant epitopes in the same molecule.	two monoclonal antibodies (iib5 and ic12) specific for the gp52 coat glycoprotein of mouse mammary tumor virus are directed against epitopes on the gp52 that are sensitive to a non-ionic detergent, nonidet p-40. there are other epitopes on this molecule that are stable in the detergent, as seen in immunoprecipitation studies with other anti-gp52 monoclonal antibodies (ve7, iiia1, ivc11).	1983	6197632