Disease relevance of Mammary Tumor Virus, Mouse

• Endogenous mouse mammary tumor virus (MMTV) proviruses have recently been shown to cosegregate genetically with the minor lymphocyte-stimulating loci, also termed self-superantigens [1].
• 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 [2].
• A continuous line of buffalo rat hepatoma (HTC) cells has been successfully infected with mouse mammary tumor virus (MMTV) produced by the GR mammary tumor cell line [3].
• 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 [4].
• For these experiments, we used human T47D breast cancer cells in which the mouse mammary tumor virus (MMTV) promoter, stably assembled as chromatin, is constitutively hypersensitive to endonucleolytic cleavage [5].

Psychiatry related information on Mammary Tumor Virus, Mouse

• In this study, the Bald/c-MMTV (mouse mammary tumor virus) mouse strain was chosen as an animal model: MMTV leads to tumor initiation, and dietary factors influence tumor promotion over a relatively long latency period [6].

High impact information on Mammary Tumor Virus, Mouse

• GAL4, a protein that activates transcription in yeast, is shown to activate the mouse mammary tumor virus promoter in mammalian cells [7].
• We also show that GAL4 and the glucocorticoid receptor activate the mouse mammary tumor virus promoter synergistically [7].
• Transcriptional activation of the int-1 gene by proviral insertion mutations is thought to be a key step in mammary tumor induction by the mouse mammary tumor virus (MMTV) [8].
• Steroid-dependent interaction of transcription factors with the inducible promoter of mouse mammary tumor virus in vivo [9].
• We have used exonuclease protection in vivo as an assay to detect interaction of nuclear factors with the steroid-inducible promoter of mouse mammary tumor virus [9].

Chemical compound and disease context of Mammary Tumor Virus, Mouse

• Dexamethasone-mediated induction of mouse mammary tumor virus RNA: a system for studying glucocorticoid action [10].
• The 5-methylcytosine content of mouse mammary tumor virus (MMTV)-specific DNA sequences acquired by both milk-borne infection and genetic transmission was determined for both normal and neoplastic tissues of the mouse [11].
• As a first step toward assessing the role of individual c-Src family tyrosine kinases in PyV middle T antigen-induced mammary tumorigenesis, we have crossed transgenic mice carrying the mouse mammary tumor virus (MMTV)/PyV middle T antigen fusion gene with mice bearing a disrupted c-src proto-oncogene [12].
• We have previously shown (1, 2) that mice with mammary tumors can always be identified by their very high plasma levels of gp52, a 52,000 mol wt glycoprotein of the mouse mammary tumor virus (MMTV) [13].
• Expression of mouse mammary tumor virus (MuMTV) in MJY-alpha mammary tumor cells was only transiently stimulated by exposure to 14 microM hydrocortisone (HC) [14].

Biological context of Mammary Tumor Virus, Mouse

• Steroid hormones induce transcription from the mouse mammary tumor virus (MMTV) promoter by complex mechanisms requiring binding of the hormone receptors to the hormone responsive element (HRE) of the long terminal repeat region [15].
• With the use of a tandem array of mouse mammary tumor virus reporter elements and a form of glucocorticoid receptor labeled with green fluorescent protein, targeting of the receptor to response elements in live mouse cells was observed [16].
• The translational positions of nucleosomes in the promoter region of the mouse mammary tumor virus (MMTV) were defined at high resolution [17].
• Endogenous superantigens, classically termed minor lymphocyte-stimulating (Mls) antigens, were recently identified as products of open reading frames (ORF) in integrated proviral copies of mouse mammary tumor virus (MMTV) [18].
• Transgenic mice expressing either the mouse mammary tumor virus (MMTV) superantigen gene (sag) alone or in combination with the viral envelope genes (env) (LEL), or all of the viral genes (gag, pol, env, and sag) (HYB PRO), deleted V beta 14+ T cells from their immune repertoire [19].

Anatomical context of Mammary Tumor Virus, Mouse

• The superantigen encoded by the mouse mammary tumor virus (MMTV) is a potent stimulator of T cells when bound to MHC class II molecules [20].
• Antigen(s) related to the major external glycoprotein (gp52) of mouse mammary tumor virus was detected in the human breast cancer cell line MCF-7 [21].
• To produce monospecific IgA antibodies against mouse mammary tumor virus (MMTV) and reovirus type 1, Peyer's patch cells from mucosally immunized mice were fused with myeloma cells, generating hybridomas that secreted virus-specific IgA antibodies in monomeric and polymeric forms [22].
• The subcellular localization of mouse mammary tumor virus (MMTV) glycoproteins was analyzed in infected and cloned rat hepatocarcinoma cells cultured with the MMTV transcriptional inducer dexamethasone [23].
• Mice in breeding colonies of feral Mus musculus brevirostris (Azrou, Morocco), M. m. musculus (Studenec, Czechoslovakia), and M. m. molossinus (Fukuoka, Japan) were found to lack the mouse mammary tumor virus (MMTV-alpha) proviral genome in their germ line [24].

Gene context of Mammary Tumor Virus, Mouse

• When transiently expressed, the two hPR forms similarly activated transcription from reporter genes containing a single palindromic progestin responsive element (PRE), while form B was more efficient at activating the PRE of the mouse mammary tumor virus long terminal repeat [25].
• To induce such events and to identify the genes involved, we have infected Wnt-1 transgenic mice with mouse mammary tumor virus (MMTV), intending to insertionally activate, and thereby molecularly tag, cooperating protooncogenes [26].
• MCF-7 cells, which endogenously express ERalpha, were stably transfected with mouse mammary tumor virus promoter-luciferase (MMTV-LUC) reporter and GR expression constructs [27].
• To determine if Neu is dominant over transforming growth factor beta (TGF-beta), we crossed mouse mammary tumor virus (MMTV)-Neu mice with MMTV-TGF-beta1(S223/225) mice expressing active TGF-beta1 in the mammary gland [28].
• To directly test the role of c-Rel in breast tumorigenesis, mice were generated in which overexpression of mouse c-rel cDNA was driven by the hormone-responsive mouse mammary tumor virus long terminal repeat (MMTV-LTR) promoter, and four founder lines identified [29].

Analytical, diagnostic and therapeutic context of Mammary Tumor Virus, Mouse

• We have studied the interaction between human glucocorticoid receptors and mouse mammary tumor virus (MMTV) DNA by means of a procedure that permits analysis after immobilization of the receptor on nitrocellulose [30].
• Because mouse mammary tumor virus (MMTV) is unable to infect Chinese hamster cells, we used phenotypic screening of the T31 mouse/hamster radiation hybrid panel to map the MMTV cell entry receptor gene and subsequently found that it is transferrin receptor 1 [31].
• The ultrastructure of budding mouse mammary tumor virus during dexamethasone stimulation, determined by scanning and transmission electron microscopy, and the significance of such an in vitro system for viral immunodiagnosis are discussed [32].
• We have used matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) to directly analyze protein profiles in mouse mammary tumor virus/HER2 transgenic mouse frozen tumor sections after treatment with the erbB receptor inhibitors OSI-774 and Herceptin [33].
• Radioimmunoassay capable of measuring mouse mammary tumor virus (MMTV) 52,000 M.W. envelope glycoprotein (gp52) and 27,000 M.W. protein (p27) have been used to quantitatively compare plasma concentrations of these viral antigens in mice bearing spontaneous mammary tumors [34].

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