Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
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| the pea3 subfamily ets genes are required for her2/neu-mediated mammary oncogenesis. | the pea3 ets transcription factor is overexpressed in the vast majority of human breast tumors and in nearly all of those of the her2/neu-positive subclass. pea3 is also overexpressed in various transgenic mouse models of this disease. whether pea3 plays an essential role in her2/neu-mediated oncogenesis has heretofore not been addressed. | 2001 | 11719215 |
| transgenic polyoma middle-t mice model premalignant mammary disease. | mice transgenic for the polyomavirus middle t (pyv-mt) gene have been widely used to study mammary tumorigenesis and metastasis. although numerous molecular insights were gained from the analysis of these transgenic malignant tumors, the early events leading to malignant transformation have not been systematically investigated nor has the biological potential of hyperplastic lesions been documented. this paper presents the first comprehensive histopathological characterization of transgenic pyv- ... | 2001 | 11719463 |
| natural cd4+ cd25+ regulatory t cells. their role in the control of superantigen responses. | cd4 regulatory t cells have a major role in controlling the immune response to self and foreign antigens. natural cd4+ cd25+ t cells are a major component of the regulatory subset. their absence is associated with the development of autoimmune and inflammatory diseases and with abnormal peripheral t-cell homeostasis. two main characteristics discriminate natural cd4+ cd25+ t cells from their cd4+ cd25- counterparts, namely their cytokine production profile and their behavior during tolerance ind ... | 2001 | 11722633 |
| conditional deletion of the bcl-x gene from mouse mammary epithelium results in accelerated apoptosis during involution but does not compromise cell function during lactation. | in the mammary gland bcl-x is the most abundant cell survival factor from the bcl-2 family. since bcl-x null mice die around day 12 of embryogenesis, the relevance of this protein in organ development and function is poorly understood. in erythroid cells bcl-x gene expression is controlled by cytokines and the transcription factor stat5 (signal transducer and activator of transcription). however, we identified that bcl-x rna levels in mammary tissue from prolactin receptor- and stat5-null mice w ... | 2001 | 11731240 |
| androgen responsiveness of the pituitary gonadotrope cell line lbetat2. | androgens have a profound effect on the hypothalamic-pituitary axis by reducing the synthesis and release of the pituitary gonadotropin lh. the effect on lh is partly a consequence of a direct, steroid-dependent action on pituitary function. although androgen action has been well studied in vivo, in vitro cell models of androgen action on pituitary gonadotropes have been scarce. recently, an lh-expressing cell line, lbetat2, was generated by tumorigenesis targeted to the lh-producing cells of th ... | 2001 | 11524240 |
| differential migration of in vivo primed b and t lymphocytes to lymphoid and non-lymphoid organs. | our study describes tissue-specific migration of t and b cells during a localized anti-viral immune response. after mouse mammary tumor virus (mmtv) injection, b lymphocytes of the draining lymph node become infected and present a retroviral superantigen to cd4(+) t lymphocytes. infected b cells receive superantigen-mediated help in a fashion comparable to classical immune responses. to investigate the fate of t and b lymphocytes that had interacted via cognate help in the same peripheral lymph ... | 2001 | 11536158 |
| glucocorticoid-regulated expression of exogenous human growth hormone gene in rats. | the aim of this study was to control in vitro and in vivo expression of the growth hormone (gh) gene using a glucocorticoid-sensitive promoter, the mouse mammary tumor virus long terminal repeat (mmtv ltr). we inserted the cdna encoding the 20-kda form of human gh (20k-gh) downstream of the mmtv ltr of plasmid pmsg, and used lipofection to transfer it to 3y1 cells together with plasmid pmx, which contains a puromycin-resistant element. the secretion of gh from the selected transformants was dose ... | 2001 | 11545618 |
| progesterone receptor isoform a inhibits isoform b-mediated transactivation in human amnion. | human amnion cells were transfected with progesterone receptor a and/or b, and the progesterone-dependent reporter construct, mouse mammary tumor virus promoter (mmtv), linked to a luciferase gene. in progesterone receptor b-expressing amnion that had been cultured before the onset of labour, treatment with progesterone resulted in an eightfold increase of the reporter activity, whereas in laboured cells, no such increase was seen. in contrast, progesterone receptor a was a weak activator of tra ... | 2001 | 11553358 |
| analyzing the contributions of chromatin structure in nuclear hormone receptor activated transcription in vivo. | the authors have described three approaches for analyzing the chromatin architecture of a steroid-responsive promoter. mnase allows one to map the positions of nucleosomes on the target gene. the more sensitive restriction enzyme hypersensitivity procedure permits detection of changes in chromatin architecture upon hormonal stimulation. additional insight into transcriptional regulation of a gene can be obtained by using the related exoiii footprinting protocol, which provides complementary data ... | 2001 | 11554329 |
| in vitro analysis of transcriptional repression of the mouse mammary tumor virus promoter. | transcription of the proviral dna of mouse mammary tumor virus (mmtv) is induced by several classes of hormone-activated steroid receptor proteins. basal promoter activity in the absence of receptor-mediated activation is selectively repressed by a distal negative regulatory element (dnre) centered approximately 400 bp upstream of the transcription initiation site. an in vitro transcription system based on synthetic t-free cassette templates was developed to assess mmtv promoter activity, and dn ... | 2001 | 11554742 |
| sequence and genetic analyses of the 3' terminus and integration sites of the riii/sa mouse mammary tumor (mmtv) exogenous provirus. | the riii/sa mouse mammary tumor virus (mmtv) is one of several exogenous mmtv viruses transmitted to suckling mice through the milk. we report herein the nucleotide sequence of the exogenous riii/sa provirus from the central eco ri site through to the end of the u5 region encoded by the 3' ltr. we also provide a detailed sequence analysis often different 3' terminal exogenous mmtv proviral integration sites within mammary tumor dna obtained by the technique of genome walking. using a combination ... | 2001 | 11556399 |
| differential interactions of specific nuclear factor i isoforms with the glucocorticoid receptor and stat5 in the cooperative regulation of wap gene transcription. | the distal region (-830 to -720 bp) of the rat whey acidic protein (wap) gene contains a composite response element (core), which has been demonstrated previously to confer mammary gland-specific and hormonally regulated wap gene expression. point mutations in the binding sites for specific transcription factors present within this core have demonstrated the importance of both nuclear factor i (nfi) and stat5 as well as cooperative interactions with the glucocorticoid receptor (gr) in the regula ... | 2001 | 11564870 |
| analysis of glucocorticoid and androgen receptor gene fusions delineates domains required for transcriptional specificity. | androgen receptor (ar) and glucocorticoid receptor (gr) influence distinct physiologic responses in steroid-responsive cells despite their shared ability to selectively bind in vitro to the same canonical dna sequence (tgttct). while the dna-binding domains (dbds) of these receptors are highly conserved, the amino n-terminal domain (ntd) and hormone-binding domain (hbd) are evolutionarily divergent. to determine the relative contribution of these functional domains to steroid-specific effects in ... | 2001 | 11572317 |
| mmtv promoter hypomethylation is linked to spontaneous and mnu associated c-neu expression and mammary carcinogenesis in mmtv c-neu transgenic mice. | the erbb family of receptor tyrosine kinases is frequently implicated in neoplasia. amplification and overexpression of erbb2/neu has been found in 20 to 40% of human breast cancers. previous studies using mmtv/c-neu transgenic mice have linked rat neu overexpression to mammary tumor development. in this study, we provide evidence that rat neu overexpression in mammary tumors of mmtv/c-neu transgenic mice is always associated with demethylation of the mmtv promoter, whereas the normal mammary gl ... | 2001 | 11593408 |
| molecular cloning and characterization of human wnt3. | mouse wnt-3 is a proto-oncogene, which is activated by mouse mammary tumor virus (mmtv). human wnt3 cdna fragment, previously isolated by another group, corresponds to a partial coding sequence. wnt3 cdna, spanning the complete coding sequence, was isolated in this study. wnt3 encoded 355-amino-acid polypeptide with the n-terminal signal peptide and two n-linked glycosylation sites. wnt3 was most homologous to wnt3a (84.2% total amino-acid identity) among human wnts. the wnt3 gene on the human c ... | 2001 | 11604997 |
| zinc-metallothionein levels are correlated with enhanced glucocorticoid responsiveness in mouse cells exposed to zncl(2), hgcl(2), and heat shock. | metallothioneins (mts) are the major low molecular weight, zinc-binding proteins in mammalian cells. it has been hypothesized that they play a role in the function of zinc-dependent signal transduction proteins and transcription factors. we investigated the capacity of zinc and other metal ions and conditions to increase both zn-associated mt levels and the receptiveness of cells to transcriptional activation mediated by the zinc-dependent glucocorticoid receptor (gr). we studied, in a gr-respon ... | 2001 | 11606802 |
| maspin expression inversely correlates with breast tumor progression in mmtv/tgf-alpha transgenic mouse model. | maspin is a novel serine protease inhibitor (serpin) with tumor suppressive activity. to date, despite the mounting evidence implicating the potential diagnostic/prognostic and therapeutic value of maspin in breast and prostate carcinoma, the lack of a suitable animal model hampers the in vivo investigation on the role of maspin at different stages of tumor progression. in this study, we used mmtv/tgf-alpha transgenic mouse model to study the expression profile of maspin in mammary tumor progres ... | 2001 | 11641778 |
| sleeping with the enemy--endogenous superantigens in humans. | we usually think of superantigens (sag) as dangerous toxins that may cause toxic shock syndrome and death. now, based on two papers in this issue of immunity, it seems that we all have sag genes within us, lying dormant and waiting to be activated under special circumstances. | 2001 | 11672533 |
| interleukin-4 up-regulates mouse mammary tumor virus expression yet is not required for in vivo virus spread. | the mouse mammary tumor virus (mmtv) superantigen induces t-cell production of cytokines, such as interleukin-4, which in turn increase mmtv transcription. however, interleukin-4 is not required for in vivo virus spread, because mice lacking interleukin-4 or the stat6 transcription factor showed wild-type infection of lymphoid and mammary tissue. in spite of this, mammary tumor incidence was decreased in stat6 null mice. | 2001 | 11689671 |
| antidepressants enhance glucocorticoid receptor function in vitro by modulating the membrane steroid transporters. | 1. previous data demonstrate that the tricyclic antidepressant, desipramine, induces glucocorticoid receptor (gr) translocation from the cytoplasm to the nucleus in l929 cells and increases dexamethasone-induced gr-mediated gene transcription in l929 cells stably transfected with the mouse mammary tumour virus-chloramphenicol acetyltransferase (mmtv-cat) reporter gene (lmcat cells) (pariante et al., 1997). 2. to extend these findings, the present study has investigated the effects of 24 h coincu ... | 2001 | 11704655 |
| induction of germinal centers by mmtv encoded superantigen on b cells. | it has not been established whether an endogenous superantigen (sag) expressed on b cells can induce germinal centers (gcs). an interesting model is that of mammary tumor virus encoded viral sags, which induce vigorous t cell proliferation and are predominantly expressed on activated b cells. we have used this model to analyze the possibility that direct stimulation of mtv7+ dba/2 b cells by vsag-responsive (vbeta6+) balb/c t cells can give rise to gcs. injection of balb/c scid mice i.v. with 2 ... | 2001 | 11785670 |
| in vitro response of v-ha-ras transgenic mouse lymphocytes after in vivo treatment with alcohol. | oncomouse is a transgenic mouse carrying an activated v-ha-ras oncogene under the control of the mouse mammary tumor virus promoter. the objective of this paper was to learn if the in vitro secretion of il-2 and ifn-gamma and the release of sil-2r by oncomice splenocytes and thymocytes depended on the presence of the oncogene product, on the in vivo pretreatment with alcohol, or on the in vitro treatment with cocaine or morphine. oncomice thymocytes released less sil-2r than fvb thymocytes. alco ... | 2001 | 11792018 |
| in vitro response of v-ha-ras transgenic mouse lymphocytes after in vivo treatment with cocaine. | oncomouse is a transgenic mouse carrying an activated v-ha-ras oncogene under the control of the mouse mammary tumor virus promoter. the objective of this paper was to learn if the in vitro secretion of il-2 and ifn-gamma and the release of sil-2r by oncomice spleen and thymus cells depended on the presence of the oncogene product, on the in vivo pretreatment with cocaine, or on the in vitro treatment with cocaine or morphine. oncomice thymocytes from different experimental groups released less ... | 2001 | 11792019 |
| mmtv-like env gene sequences in human breast cancer. | we have previously detected an mmtv env gene-like 660 bp sequence in 38% of human breast cancers, but not in normal tissues or other tumors. in this communication we report the sequences from eleven tumors and three breast cancer cell lines, and compare them to four strains of mmtv and to the known endogenous retroviral sequences. the breast cancer sequences were highly homogenous to the mmtv's, but not to the endogenous sequences suggesting an exogenous origin. | 2001 | 11266212 |
| transgenic muc1 interacts with epidermal growth factor receptor and correlates with mitogen-activated protein kinase activation in the mouse mammary gland. | muc1 is a large (>400 kda), heavily glycosylated transmembrane protein that is aberrantly expressed on greater than 90% of human breast carcinomas and subsequent metastases. the precise function of muc1 overexpression in tumorigenesis is unknown, although various domains of muc1 have been implicated in cell adhesion, cell signaling, and immunoregulation. stimulation of the mda-mb-468 breast cancer line as well as mouse mammary glands with epidermal growth factor results in the co-immunoprecipita ... | 2001 | 11278868 |
| spatial and temporal expression of the cre gene under the control of the mmtv-ltr in different lines of transgenic mice. | cre-loxp based gene deletion approaches hold great promise to enhance our understanding of molecular pathways controlling mammary development and breast cancer. we reported earlier the generation of transgenic mice that express the cre recombinase under the control of the mouse mammary tumor virus (mmtv) long terminal repeat (ltr). these mice have become a valuable research tool to delete genes specifically in the mammary gland, other secretory organs, and the female germline. we have now charac ... | 2001 | 11817542 |
| glucocorticoids suppress human immunodeficiency virus type-1 long terminal repeat activity in a cell type-specific, glucocorticoid receptor-mediated fashion: direct protective effects at variance with clinical phenomenology. | glucocorticoid administration and/or excess secretion have been associated with increased human immunodeficiency virus type-1 (hiv-1) replication and aids progression. the hiv-1 long terminal repeat (ltr) promoter contains glucocorticoid-responsive element (gre)-like sequences that could mediate a positive effect of glucocorticoids on hiv-1. in addition, we recently demonstrated that the hiv-1 accessory protein vpr is a potent coactivator of the glucocorticoid receptor, which, like the host coac ... | 2000 | 11282284 |
| tyrosine kinase signalling in breast cancer: fibroblast growth factors and their receptors. | the fibroblast growth factors [fgfs (murine), fgfs (human)] constitute a large family of ligands that signal through a class of cell-surface tyrosine kinase receptors. fgf signalling has been associated in vitro with cellular differentiation as well as mitogenic and motogenic responses. in vivo, fgfs are critical for animal development, and some have potent angiogenic properties. several fgfs have been identified as oncogenes in murine mammary cancer, where their deregulation is associated with ... | 2000 | 11250709 |
| genetically engineered mouse models of mammary intraepithelial neoplasia. | foci of atypical mammary epithelium have been associated with breast cancer in many species including mouse and man. the advent of targeted genomics has led to the creation of numerous genetically engineered mice (gem) which display focal atypical lesions associated with mammary cancer. some early lesions in gem have a remarkable morphological similarity to pre-cancers in humans. while the malignant potential of atypical foci have been thoroughly documented in the non-gem by tissue transplantati ... | 2000 | 14973386 |
| detection of viral superantigen-class ii mhc interactions at the cell surface. | mouse mammary tumor virus superantigens (vsags) must bind to class ii mhc proteins to activate t cells. although direct interaction of vsags with class ii proteins has been demonstrated biochemically, the details of this interaction are largely unresolved. to facilitate the study of class ii-vsag interactions, a sensitive assay has been developed that can detect binding of vsags to class ii proteins on the cell surface. the assay measures changes in vsag surface expression upon enzymatic removal ... | 2000 | 11395137 |
| pairing of vbeta6 with certain valpha2 family members prevents t cell deletion by mtv-7 superantigen. | superantigens (sag) are proteins of bacterial or viral origin able to activate t cells by forming a trimolecular complex with both mhc class ii molecules and the t cell receptor (tcr), leading to clonal deletion of reactive t cells in the thymus. sag interact with the tcr through the beta chain variable region (vbeta), but the tcr alpha chain has been shown to have an influence on the t cell reactivity. we have investigated here the role of the tcr alpha chain in the modulation of t cell reactiv ... | 2000 | 11395139 |
| serum antibodies reactive with non-human primate retroviruses identified in acute onset schizophrenia. | schizophrenia is a pervasive neuropsychiatric disease of uncertain etiology. previous studies have postulated that retroviruses may contribute to the etiology of some cases of schizophrenia. we examined the possible relationship between retroviral infection and schizophrenia by measuring antibodies to a number of different primate retroviruses in the sera of individuals undergoing their first hospitalization for this disease. sera from patients with first onset schizophrenia and matched healthy ... | 2000 | 11175321 |
| clinical and endoscopic aspects in the evolution of patients with bleeding peptic ulcer--a cohort study. | bleeding ulcers are a major problem in public health and represent approximately half of all the cases of upper gastrointestinal hemorrhage in the united states. this study aims to determine the prognostic value of factors such as clinical history, laboratory and endoscopic findings in the occurrence of new episodes of bleeding in patients who have upper gastrointestinal hemorrhage caused by gastric or duodenal peptic ulcer. | 2000 | 11236268 |
| [new discoveries in experimental cancer]. | this 7th international symposium organized by the national academy of medicine on new directions in cancer management, was sponsored by iucc (international union against cancer) and received important financial assistance from the fritz bender foundation. in 1996 and 97, the first two symposia also dealt with cancer, specifically with tumor immunology and with the relation of human breast cancer with mmtv (murine mammary tumor virus). the aim of these introductory remarks is to emphasize recent ... | 2000 | 11188923 |
| superantigen disruption of cd8+ t and b lymphocyte homeostasis. | superantigens (sags) activate th cells and induce their differentiation into cytokine-producing effector cells. supranormal cytokine production is characteristic of sag-induced polyclonal th activation. study of this interaction has focused upon th cell function to the relative exclusion of other lymphocyte populations. sags also impact cells dependent upon th cells for their differentiation and disrupt the normal homeostasis of the immune system. in this report, several changes in lymphocyte bi ... | 2000 | 11205378 |
| a reduction in blood insulin levels as a host endocrine response during tumor development. | it has been previously reported that endogenous insulin levels decrease during tumor growth. we have now studied whether this host endocrine response is independent of the way in which the tumor is induced. for this purpose, animals transplanted with tumor cells induced by 3-methylcholanthrene (mca) or 7,12-dimethylbenz(a) anthracene (dmba), or with el-4 lymphoma cells, and animals that develop autochthonous tumors induced by mca or the murine mammary tumor virus (mmtv) were used. these procedur ... | 2000 | 11137618 |
| mechanisms of retrovirus-induced oncogenesis. | retroviruses are implicated in a series of human and animal tumours such as leukaemias, mammary tumours or skin cancer. the mechanism that they use to induce tumour formation varies. insertional mutagenesis is a common mechanism in rodent, feline and avian retroviruses, where the retrovirus integrates into the host genome and affects the transcription of the neighbouring genes. cloning of these affected genes led to identification of a series of oncogenes that play a significant role in the indu ... | 2000 | 11140855 |
| the glucocorticoid receptor and stat6 physically and functionally interact in t-lymphocytes. | in lymphocytes, glucocorticoids (gc)- and interleukin-4-signaling pathways are known to interact, as evidenced by inhibition of il-4-mediated proliferation by dexamethasone or suppression of gc-induced apoptosis by il-4. in this study, we characterized the molecular basis for this reciprocal interference. we report that, in murine ctll-2 cells, il-4 inhibits gc-induced mmtv (mouse mammary tumor virus) promoter transactivation, and that gc suppress il-4-induced transactivation of a stat6 (signal ... | 2000 | 11150515 |
| derivation and initial characterization of a mouse mammary tumor cell line carrying the polyomavirus middle t antigen: utility in the development of novel cancer therapeutics. | here we describe the derivation of novel cell lines from spontaneous mammary tumors that arose in mouse mammary tumor virus-polyomavirus (mmtv-pyv) middle t (midt) transgenic mice. clonal cell lines from four mixed cell populations were tested for adenovirus transducibility and sensitivity to p53 tumor suppressor gene therapy mediated by sch58500, a replication-deficient adenovirus that expresses human p53. the midt2-1 cell line was selected for further characterization in vitro and in vivo. thi ... | 2000 | 11156413 |
| ligand-activated progesterone receptor isoform hpr-a is a stronger transactivator than hpr-b for the expression of igfbp-1 (insulin-like growth factor binding protein-1) in human endometrial stromal cells. | in human endometrium, the levels of progesterone receptor (pr) isoforms hpr-a and hpr-b are differentially regulated during the reproductive cycle. progesterone significantly increases the content of hpr-a, the predominant isoform in decidualized stromal cells (1). the purpose of this study was to determine the capacity of hpr-a and hpr-b to transactivate the progestin-dependent target gene in human endometrial stromal cells. we examined the effect of cotransfection of hpr-a or hpr-b on the expr ... | 2000 | 11117526 |
| synchronous deletion of mtv-superantigen-reactive thymocytes in the cd3(medium/high) cd4(+)cd8(+) subset. | multiple model systems have demonstrated that negatively selected thymocytes can be deleted during the immature cd4(+)cd8(+) cd3(low) stage after high affinity interaction of t-cell receptors (tcrs) with antigen:major histocompatibility complex (mhc) complexes. superantigens (sags) derived from endogenous mammary tumour viruses (mtv) induce negative selection of mtv-sag-reactive thymocytes regardless of which peptide antigen is presented by mhc molecules. in this study, the timing of deletion of ... | 2000 | 11119259 |
| nh2-terminal cleavage of xenopus fibroblast growth factor 3 is necessary for optimal biological activity and receptor binding. | fibroblast growth factor 3 (fgf3) was originally identified as the mouse proto-oncogene int-2, which is activated by proviral insertion in tumors induced by mouse mammary tumor virus. to facilitate the biological characterization of the ligand, we have analyzed its homologue in xenopus laevis, xfgf3. here we confirm that the x. laevis genome contains two distinct fgf3 alleles, neither of which is capable of encoding the nh2-terminally extended forms specified by the mouse and human fgf3 genes. u ... | 2000 | 11095248 |
| requirement for reverse immune surveillance for the growth of germinal center-derived murine lymphomas. | the concept of reverse immune surveillance, first conceived over 12 years ago, described the relationship that existed between germinal center-derived b cell lymphoma cells and the host immune system in sjl/j mice. according to reverse immune surveillance, recognition of tumor cell antigens and a response by the host immune system is required for tumor growth. the phenomenon of reverse immune surveillance related to b cell lymphomas has recently also been characterized in another inbred mouse st ... | 2000 | 11100880 |
| matrix metalloproteinase 9 promoter activity is induced coincident with invasion during tumor progression. | matrix metalloproteinase 9 (mmp-9, also known as gelatinase b or 92-kd type iv collagenase) is overexpressed in many human and murine cancers. we induced carcinomas in mice carrying a transgene that links the mmp-9 promoter to the reporter ss-galactosidase so that activation of the mmp-9 promoter would be indicated by ss-galactosidase. mammary carcinomas were induced by mating the mmp-9 promoter reporter transgenic mice with mice carrying a transgene for murine mammary tumor virus promoter linke ... | 2000 | 11106549 |
| conditional deletion of the bcl-x gene from erythroid cells results in hemolytic anemia and profound splenomegaly. | bcl-x is a member of the bcl2 family and has been suggested to be important for the survival and maturation of various cell types including the erythroid lineage. to define the consequences of bcl-x loss in erythroid cells and other adult tissues, we have generated mice conditionally deficient in the bcl-x gene using the cre-loxp recombination system. the temporal and spatial excision of the floxed bcl-x locus was achieved by expressing the cre recombinase gene under control of the mmtv-ltr. by ... | 2000 | 11044408 |
| the region between amino acids 245 and 265 of the bovine leukemia virus (blv) tax protein restricts transactivation not only via the blv enhancer but also via other retrovirus enhancers. | bovine leukemia virus (blv) is associated with enzootic bovine leukosis and is closely related to human t-cell leukemia virus type 1 (htlv-1). the tax protein of blv acts through the 5' long terminal repeat (ltr) of blv and activates the transcription of blv. in this study, we amplified tax genes from blv-infected cattle using pcr. we cloned the genes and monitored the transcriptional activities of the products. seven independent mutant tax proteins, with at least one amino acid substitution bet ... | 2000 | 11069988 |
| a fission yeast homolog of int-6, the mammalian oncoprotein and eif3 subunit, induces drug resistance when overexpressed. | through a screen to identify genes that induce multi-drug resistance when overexpressed, we have identified a fission yeast homolog of int-6, a component of the human translation initiation factor eif3. disruption of the murine int-6 gene by mouse mammary tumor virus (mmtv) has been implicated previously in tumorigenesis, although the underlying mechanism is not yet understood. fission yeast int6 was shown to interact with other presumptive components of eif3 in vivo, and was present in size fra ... | 2000 | 11071922 |
| fission yeast int6 is not essential for global translation initiation, but deletion of int6(+) causes hypersensitivity to caffeine and affects spore formation. | mammalian int6 protein has been considered to be a subunit of the eukaryotic translation initiation factor, eif3. the int6 locus is also known as a common integration site of mouse mammary tumor virus (mmtv). however, the function of int6 in translation initiation and the mechanism of int6-mediated tumor induction are yet to be explored. in this study, the fission yeast, schizosaccharomyces pombe, int6(+), which is 43% identical to the mammalian counterpart, was deleted. despite the evidence tha ... | 2000 | 11071923 |
| [from gene to disease; the apc gene and familial adenomatous polyposis coli]. | familial adenomatous polyposis coli is an autosomal dominant hereditary form of colorectal cancer associated with mutations in the adenomatous polyposis coli (apc) gene on chromosome 5. the apc protein is thought to mediate the stability of beta-catenin in the wnt signaling transduction pathway ('wingless-type mouse mammary tumor virus integration site family member') in normal colonic epithelial cells, thereby indirectly regulating the expression of wnt target genes such as the c-myc-oncogene. ... | 2000 | 11072519 |
| increased immunoglobulin g, but not m, binding to endogenous retroviral antigens in hiv-1 infected persons. | the modes of interaction between products of human endogenous retroviral (herv) sequences and the immune system are largely unknown. in hiv infected persons, an exogenous retrovirus adds further complexity to the situation. therefore, 14 synthetic peptides with sequences derived from conserved regions of various endogenous retroviruses (ervs) and from related exogenous retroviruses were used to search for igg and igm antibodies that bind to such antigens in 15 hiv-1 seropositive and 17 seronegat ... | 2000 | 11074471 |
| integration of proviral sequences, but not at the common integration sites of the fgf8 locus, in an androgen-dependent mouse mammary shionogi carcinoma. | a retroviral insertional mutation, especially by mouse mammary tumor virus (mmtv), is a major cause of murine mammary tumorigenesis. prompted by our previous finding that fgf8, an insertionally activated cellular oncogene, is highly expressed in androgen-dependent mouse mammary shionogi carcinoma cells, we here investigated retroviral integration adjacent to the fgf8 locus in shionogi carcinoma. in the genomic southern blots for fgf8 and its 5'-upstream gene npm3, the hybridized fragments were i ... | 2000 | 11075944 |
| mammary tumor development in mmtv-c-myc/mmtv-v-ha-ras transgenic mice is unaffected by osteopontin deficiency. | transgenic mice expressing c-myc and v-ha-ras specifically in the mammary gland under the control of the mammary specific promoter mmtv develop unifocal mammary tumors with a half time of about 46 days, and these tumors express high levels of osteopontin mrna and protein. in order to evaluate the requirement for osteopontin expression by these tumors, we have crossed transgenic mice expressing these two oncogenes with mice with a targeted disruption of the osteopontin gene. littermates expressin ... | 2000 | 11079161 |
| non-hodgkin's lymphoma in women with breast cancer. | the purpose of this study was to describe a series of patients with breast cancer and non-hodgkin's lymphoma and to determine the usual sequence of the diagnoses. therapy for both neoplasms and its relationship to the development of the second neoplasm were also evaluated. | 2000 | 11079174 |
| effects of hiv-1 peptides on t-cell receptor variable beta chain families. | superantigens (sags) selectively stimulate expansion and then deletion of specific t cell antigen receptor (tcr) variable beta chain (vbeta) families. we investigated six synthetically produced hiv-1-related peptides for evidence of sag activity: three derived all or in part from the transmembrane gp41 protein and three from the genetic sequence of the trna binding region. the first three were chosen because they are highly immunogenic; the second three, because their genetic sequence is complet ... | 2000 | 11082512 |
| ras signaling in the inner medullary cell response to urea and nacl. | the small guanine nucleotide-binding protein ras, activated by peptide mitogens and other stimuli, regulates downstream signaling events to influence transcription. the role of ras in solute signaling to gene regulation was investigated in the murine inner medullary collecting duct (mimcd3) cell line. urea treatment (100-200 mm), but not sham treatment, increased ras activation 124% at 2 min; the effect of nacl did not achieve statistical significance. to determine the contribution of ras activa ... | 2000 | 10666033 |
| sint1, a common integration site in sl3-3-induced t-cell lymphomas, harbors a putative proto-oncogene with homology to the septin gene family. | the murine retrovirus sl3-3 is a potent inducer of t-cell lymphomas when inoculated into susceptible newborn mice. previously, dnas from twenty sl3-3-induced tumors were screened by pcr for provirus integration sites. two out of 20 tumors demonstrated clonal provirus insertion into a common region. this region has now been isolated and characterized. the region, named sl3-3 integration site 1 (sint1), maps to the distal end of mouse chromosome 11, corresponding to human chromosome 17q25, and may ... | 2000 | 10666245 |
| tamoxifen chemoprevention of a hormone-independent tumor in the proto-neu transgenic mice model. | we evaluated the effect of tamoxifen (tam) on tumor development in proto-neu transgenic mice that spontaneously develop mammary carcinomas overexpressing the neu protein. these mammary carcinomas are hormone independent because superimposable growth of transplants was observed in females and males. virgin transgenic mice treated with tam from 24 weeks of age, ie., when subclinical mammary tumors are already present, showed a slightly accelerated tumor development. in contrast, transgenic mice tr ... | 2000 | 10667575 |
| ability of systemic interleukin-12 to hamper progressive stages of mammary carcinogenesis in her2/neu transgenic mice. | previous studies in mice have shown that chronic administration of recombinant interleukin-12 (il-12) hampers the progression of both chemical- and oncogene-dependent carcinogenesis. this suggests that a new preventive strategy may be envisaged for individuals with a genetic risk of cancer or carrying preneoplastic lesions. starting at progressive stages of mammary carcinogenesis, female balb/c and fvb mice carrying the activated rat her2/neu oncogene (balb-neut) or the proto-oncogene (fvb-neun) ... | 2000 | 10667588 |
| the nmr structure of the nucleocapsid protein from the mouse mammary tumor virus reveals unusual folding of the c-terminal zinc knuckle. | the nucleocapsid protein (nc) from the mouse mammary tumor virus (mmtv) has been overexpressed in escherichia coli and purified to homogeneity for structural studies by nuclear magnetic resonance (nmr) spectroscopy. the protein contains two copies of a conserved zinc-coordinating "cchc array" or "zinc knuckle" motif common to the nucleocapsid proteins of nearly all known retroviruses. the residues comprising and adjacent to the zinc knuckles were assigned by standard two-dimensional (1)h and thr ... | 2000 | 10677209 |
| the glucocorticoid receptor: rapid exchange with regulatory sites in living cells. | steroid receptors bind to site-specific response elements in chromatin and modulate gene expression in a hormone-dependent fashion. 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. photobleaching experiments provide direct evidence that the hormone-occupied receptor undergoes rapid exchange between chromatin an ... | 2000 | 10678832 |
| a novel mechanism of resistance to mouse mammary tumor virus infection. | exogenous mouse mammary tumor virus (mmtv) is carried from the gut of suckling pups to the mammary glands by lymphocytes and induces mammary gland tumors. mmtv-induced tumor incidence in inbred mice of different strains ranges from 0 to as high as 100%. for example, mice of the c3h/hen strain are highly susceptible, whereas mice of the i/lnj strain are highly resistant. of the different factors that together determine the susceptibility of mice to development of mmtv-induced mammary tumors, gene ... | 2000 | 10684291 |
| superantigen expression is driven by both mouse mammary tumor virus long terminal repeat-associated promoters in transgenic mice. | in addition to the usual retroviral promoter, the mouse mammary tumor virus (mmtv) long terminal repeat carries a second promoter located in the u3 region. here we show that both of these promoters are independently able to give rise to superantigen activity in transgenic mice. the ability of multiple mmtv promoters to drive superantigen expression underscores its importance in the virus life cycle. | 2000 | 10684308 |
| superantigens - powerful modifiers of the immune system. | superantigens are powerful microbial toxins that activate the immune system by binding to class ii major histocompatibility complex and t-cell receptor molecules. they cause a number of diseases characterized by fever and shock and are important virulence factors for two human commensal organisms, staphylococcus aureus and streptococcus pyogenes, as well as for some viruses. their mode of action and variation around the common theme of over-stimulating t cells, provides a rich insight into the c ... | 2000 | 10689316 |
| hormone activation induces nucleosome positioning in vivo. | the mouse mammary tumor virus (mmtv) promoter is induced by glucocorticoid hormone. a robust hormone- and receptor-dependent activation could be reproduced in xenopus laevis oocytes. the homogeneous response in this system allowed a detailed analysis of the transition in chromatin structure following hormone activation. this revealed two novel findings: hormone activation led to the establishment of specific translational positioning of nucleosomes despite the lack of significant positioning in ... | 2000 | 10698943 |
| over-expression of erbb-2/neu is paralleled by inhibition of mouse-mammary-epithelial-cell differentiation and developmental apoptosis. | the erbb-2/neu oncogene is frequently over-expressed in many different tumors in humans, including those of breast and ovary. the oncogene encodes a receptor tyrosine kinase closely related to the epidermal-growth-factor receptor. we studied effects on differentiation and cell death of erbb-2/neu during mammary-gland development in transgenic mice expressing an activated, oncogenic rat erbb-2/neu gene controlled by the mammary-gland-specific promoter from mouse-mammary-tumor virus (mmtv-ltr). tr ... | 2000 | 10699933 |
| tcr v(beta) repertoire restriction and lack of cdr3 conservation implicate tcr-superantigen interactions in promoting the clonal evolution of murine thymic lymphomas. | thymic lymphoma development is a multistage process in which genetic and epigenetic events cooperate in the emergence of a malignant clone. the notion that signaling via tcr-ligand interactions plays a role in promoting the expansion of developing neoplastic clones is a matter of debate. to investigate this issue, we determined the tcr v(beta) repertoire of thymic lymphomas induced in akr/j mice by either endogenous retroviruses or the carcinogen, n-methyl-n-nitrosourea (mnu). both spontaneous a ... | 2000 | 10700461 |
| alternative proteolytic processing of mouse mammary tumor virus superantigens. | mouse mammary tumor viruses express a superantigen essential for their life cycle. it has been proposed that viral superantigens (vsags) require processing by prohormone convertases (pcs) for activity. we now observe, using a panel of mutant forms of potential pc cleavage sites and in vitro cleavage assays, that only the cs1 (position 68 to 71) and cs2 (position 169 to 172) sites are utilized by furin and pc5. other members of the convertase family that are expressed in lymphocytes are not endow ... | 2000 | 10708421 |
| mouse models for breast cancer. | 2000 | 10713679 | |
| mmtv-induced mammary tumorigenesis: gene discovery, progression to malignancy and cellular pathways. | the study of the mouse mammary tumor virus (mmtv) has provided important insights into the mechanisms of gene transcription regulation by steroid hormones, the mode of action of heritable super antigens and the progressive nature of neoplastic transformation in the mammary gland. here we describe the current situation with respect to the latter aspect of mmtv biology and the prospects for further advance in our understanding of breast cancer in humans that may be expected from a continued study ... | 2000 | 10713682 |
| use of mmtv-wnt-1 transgenic mice for studying the genetic basis of breast cancer. | wnt-1 was first identified as a protooncogene activated by viral insertion in mouse mammary tumors. transgenic expression of this gene using a mouse mammary tumor virus ltr enhancer causes extensive ductal hyperplasia early in life and mammary adenocarcinomas in approximately 50% of the female transgenic (tg) mice by 6 months of age. metastasis to the lung and proximal lymph nodes is rare at the time tumors are detected but frequent after the removal of the primary neoplasm. the potent mitogenic ... | 2000 | 10713683 |
| genetic determinants of response to chemotherapy in transgenic mouse mammary and salivary tumors. | several transgenic mouse tumor models were utilized to explore how specific genetic alterations affect the tumor cell response to chemotherapeutic agents in vivo. specifically, mmtv-ras transgenic mice were interbred to p53 knock-out mice to create a model for assessing the role of p53 in chemotherapeutic responses. in addition, mmtv-ras tumors were compared to mmtv-myc and mmtv-ras/myc tumors. mice of each genotype reproducibly develop mammary and/or salivary tumors, but tumor growth dynamics v ... | 2000 | 10713698 |
| a stable prostatic bioluminescent cell line to investigate androgen and antiandrogen effects. | we developed a new stable prostatic cell line expressing the human androgen receptor (ar) and the ar-responsive reporter gene to generate a powerful tool for investigating androgen action and for rapid screening of agonists and antagonists. the ar-deficient pc-3 cells were stably transfected with psg(5)-puro-har and pmmtv-neo-luc. after selection with puromycin and neomycin, one highly inducible clone was isolated and named palm, for pc-3-androgen receptor-luciferase-mmtv. the expression of har ... | 2000 | 10715537 |
| comparison of nucleosome remodeling by the yeast transcription factor pho4 and the glucocorticoid receptor. | chromatin reorganization of the pho5 and murine mammary tumor virus (mmtv) promoters is triggered by binding of either pho4 or the glucocorticoid receptor (gr), respectively. in order to compare the ability of pho4 and gr to remodel chromatin and activate transcription, hybrid promoter constructs were created by insertion of the mmtv b nucleosome sequence into the pho5 promoter and then transformed into a yeast strain expressing gr. activation of either pho4 (by phosphate depletion) or gr (by ho ... | 2000 | 10722753 |
| hiv gp120 plus specific peptides are recognized in a similar manner to specific hla plus peptide by hla-restricted antigen-specific t-cell lines. | hiv induces disease only following chronic activation of the immune system. other retroviruses such as the mouse mammary tumour virus (mmtv) activate a large percentage of t cells by encoding a superantigen (sag). to date there is no evidence that hiv encodes a sag. an alternative way to induce pan-activation of the immune system is by allogeneic stimulation, which occurs following transplantation. here we extend previous work which demonstrated that hivpg120 could bind peptides in a similar man ... | 2000 | 10733164 |
| contribution of the intercalated adenosine at the helical junction to the stability of the gag-pro frameshifting pseudoknot from mouse mammary tumor virus. | the mouse mammary tumor virus (mmtv) gag-pro frameshifting pseudoknot is an h-type rna pseudoknot that contains an unpaired adenosine (a14) at the junction of the two helical stems required for efficient frameshifting activity. the thermodynamics of folding of the mmtv vpk pseudoknot have been compared with a structurally homologous mutant rna containing a g x u to g-c substitution at the helical junction (u13c rna), and an a14 deletion mutation in that context (u13cdeltaa14 rna). dual wavelengt ... | 2000 | 10744025 |
| strength and specificity of different gene promoters in oral cancer cells. | gene therapy of oral cancer will require expression of genes by promoters that are both powerful and relatively tumor specific. we compared the level of expression of a reporter gene from promoters of human cytomegalovirus (cmv), sv40 virus, mouse mammary tumor virus (mmtv), human papillomaviruses (hpv) types 16 and 18, and the human multi-drug-resistance gene (mdr1), in several lines of oral cancer cells. in the oral cancer cell line 686ln the rank order of expression levels was: cmv > sv40 > h ... | 2000 | 10745175 |
| selective activation of the glucocorticoid receptor by steroid antagonists in human breast cancer and osteosarcoma cells. | steroid hormones regulate the transcription of numerous genes via high affinity receptors that act in concert with chromatin remodeling complexes, coactivators and corepressors. we have compared the activities of a variety of glucocorticoid receptor (gr) antagonists in breast cancer and osteosarcoma cell lines engineered to stably maintain the mouse mammary tumor virus promoter. in both cell types, gr activation by dexamethasone occurs via the disruption of mouse mammary tumor virus chromatin st ... | 2000 | 10748103 |
| the mouse mammary tumor virus promoter adopts distinct chromatin structures in human breast cancer cells with and without glucocorticoid receptor. | steroid receptors represent a class of transcription regulators that act in part by overcoming the often repressive nature of chromatin to modulate gene activity. the mouse mammary tumor virus (mmtv) promoter is a useful model for studying transcriptional regulation by steroid hormone receptors in the context of chromatin. the chromatin architecture of the promoter prevents the assembly of basal transcription machinery and binding of ubiquitous transcription factors. however, in human breast car ... | 2000 | 10751396 |
| structure, stability and function of rna pseudoknots involved in stimulating ribosomal frameshifting. | programmed -1 ribosomal frameshifting has become the subject of increasing interest over the last several years, due in part to the ubiquitous nature of this translational recoding mechanism in pathogenic animal and plant viruses. all cis-acting frameshift signals encoded in mrnas are minimally composed of two functional elements: a heptanucleotide "slippery sequence" conforming to the general form x xxy yyz, followed by an rna structural element, usually an h-type rna pseudoknot, positioned an ... | 2000 | 10764589 |
| esophagogastric adenocarcinoma in an e1a/e1b transgenic model involves p53 disruption. | we studied tumorigenesis and p53 immunostaining in a murine transgenic model introducing e1a/e1b under the control of the mouse mammary tumor virus-long terminal repeat (mmtv-ltr) promoter in which adenocarcinoma occurs at the squamocolumnar junction in the foregut, predominantly in males, and at no other site. mutations of p53 are frequent in human esophageal adenocarcinoma and the e1b gene product interferes with p53-mediated apoptosis, inhibiting tumor suppression at the g(1)/s checkpoint. tr ... | 2000 | 10769092 |
| mouse mammary tumor virus-like env gene sequences in human breast tumors and in a lymphoma of a breast cancer patient. | dna sequences with very high similarity (95-98%) to the mouse mammary tumor virus (mmtv) env gene have been amplified by pcr in 38.5% of human breast tumors and in <2% of normal breast tissue (wang et al., cancer res., 55: 5173-5179, 1995). intrigued by these findings, which suggested an exogenous viral etiology for a certain percentage of human breast tumors, we have screened a panel of human breast tumors and normal breast tissue for the presence of mmtv-like dna sequences. using similar pcr p ... | 2000 | 10778951 |
| fgf4 and int2 oncogenes are amplified and expressed in kaposi's sarcoma. | kaposi's sarcoma (ks) is a vascular tumor, the pathogenesis of which has been suggested to include human herpesvirus 8 (hhv-8) as well as various cytokines and growth factors. very little is known about cytogenetic and molecular genetic changes in ks. we studied dna copy number changes in ks and found a recurrent gain at 11q13. we then analyzed the amplification and expression status of two known oncogenes, fgf4 and int2, residing at 11q13. comparative genomic hybridization, interphase fluoresce ... | 2000 | 10786811 |
| engineering viral promoters for gene transfer to human neuroblasts. | 1. the strength and activity of several viral promoters in human neuroblasts were evaluated in vitro. 2. several luciferase reporter gene constructs under the control of different viral promoters (hiv-1 ltr, htlv-i ltr, mmtv ltr, rsv ltr, cmv, sv40), in the presence or in the absence of the viral sv40 enhancer, were transfected into two well-established human neural cell lines, including one derived from human embryonic olfactory cells (b4) and one derived from an adrenal neuroblastoma (sh-sy-5y ... | 2000 | 10789837 |
| a locus closely linked to mtv7 on mouse chromosome 1 influences development of acute versus chronic graft-versus-host disease in a murine model. | the relationship between acute and chronic graft-versus-host disease (gvhd) is not well understood. a murine model of acute and chronic gvhd is the b6d2f1 parent-->f1 model in which transfer of c57bl/6 parental strain lymphoid cells to b6d2f1 recipients results in development of th1-mediated acute gvhd, whereas transfer of dba/2 parental strain lymphoid cells to b6d2f1 recipients results in development of th2-mediated chronic gvhd. numerous studies have investigated the reason for the differenti ... | 2000 | 10794427 |
| endocrine host responses during early and late phases of tumor development. | it is well established that hormones affect tumor growth. conversely, inoculation of cells obtained from tumors that had been transplanted for many generations causes changes in the concentration of different hormones before and after tumor detection. we aimed at answering the question of whether hormonal alterations also occur during the development of primary tumors and following transplantation of tumors from early generations. primary tumors were induced in mice by either the carcinogenic ag ... | 2000 | 10797255 |
| synergistic action of ga-binding protein and glucocorticoid receptor in transcription from the mouse mammary tumor virus promoter. | b lymphocytes are among the first cells to be infected by mouse mammary tumor virus (mmtv), and they play a crucial role in its life cycle. to study transcriptional regulation of mmtv in b cells, we have analyzed two areas of the long terminal repeat (ltr) next to the glucocorticoid receptor binding site, fp1 (at position -139 to -146 from the cap site) and fp2 (at -157 to -164). both showed b-cell-specific protection in dnase i in vitro footprinting assays and contain binding sites for ets tran ... | 2000 | 10799572 |
| lack of androgen receptor transcriptional activity in human keratinocytes. | since detection of androgen receptor (ar) expression in keratinocytes by immunostaining is controversial, we investigated whether keratinocytes can act as androgen target cells using transient transfection assays. chloramphenicol acetyltransferase (cat) assays for the endogenous ar transcriptional activity in hacat keratinocytes indicated that dht (10(-9)-10(-8) m) can induce less than 1.5-fold of mouse mammary tumor virus cat, which is quite low, compared with 38-fold induction by 10(-7) m 1,25 ... | 2000 | 10808125 |
| glucocorticosteroids stimulate the activity of the promoters of peripheral myelin protein-22 and protein zero genes in schwann cells. | to better understand the mechanism by which glucocorticosteroids (gluc) could enhance myelination in the pns, cultured rat schwann cells were transiently transfected with reporter constructs in which luciferase expression was controlled by the promoter region of either the peripheral myelin protein-22 (pmp22) or the protein zero (p(0)) genes. gluc stimulated the activity of the p(0) promoter and the pmp22 promoters 1 and 2. the effect of gluc was specific as estradiol and testosterone did not ac ... | 2000 | 10814728 |
| mouse mammary tumor virus-ki-rasb transgenic mice develop mammary carcinomas that can be growth-inhibited by a farnesyl:protein transferase inhibitor. | for ras oncoproteins to transform mammalian cells, they must be posttranslationally modified with a farnesyl group in a reaction catalyzed by the enzyme farnesyl:protein transferase (fptase). inhibitors of fptase have therefore been developed as potential anticancer agents. these compounds reverse many of the malignant phenotypes of ras-transformed cells in culture and inhibit the growth of tumor xenografts in nude mice. furthermore, the fptase inhibitor (fti) l-744,832 causes tumor regression i ... | 2000 | 10825141 |
| the oncoprotein kinase chaperone cdc37 functions as an oncogene in mice and collaborates with both c-myc and cyclin d1 in transformation of multiple tissues. | cdc37 encodes a 50-kda protein that targets intrinsically unstable oncoprotein kinases including cdk4, raf-1, and v-src to the molecular chaperone hsp90, an interaction that is thought to be important for the establishment of signaling pathways. cdc37 is required for proliferation in budding yeast and is coexpressed with cyclin d1 in proliferative zones during mouse development, a finding consistent with a positive role in cell proliferation. cdc37 expression may not only be required to support ... | 2000 | 10825210 |
| elevated glucocorticoid receptor transactivation and down-regulation of alpha 1 integrin are associated with loss of plasma membrane ca2+-atpase isoform 1. | we have previously shown that inhibition of expression of the plasma membrane ca(2+)-atpase isoform 1 in pc6 cells leads to loss of nerve growth factor-mediated neurite extension (brandt, p.c., sisken, j.e., neve, r.l., and vanaman, t.c. (1996) proc. natl. acad. sci. u.s.a. 93, 13843-13848). cells lacking plasma membrane ca(2+)-atpase 1 did not attach to collagen-coated plates as tightly as controls, suggesting that a defect in adhesion might be underlying the inability to extend neurites. we re ... | 2000 | 10827194 |
| differential regulation of testosterone vs. 5alpha-dihydrotestosterone by selective androgen response elements. | there are two major physiological androgens, testosterone (t), and 5alpha-dihydrotestosterone (dht), which induce different responses in mammals. these androgens regulate the target gene transcription via binding to and activating the same androgen receptor (ar). the molecular mechanisms that differ between these two very close androgens through the same ar protein to target the distinct genomic responses remain unknown. using yeast genetic selection, we identified two kinds of androgen response ... | 2000 | 10839207 |
| adaptive variation in lactate dehydrogenase-b gene expression: role of a stress-responsive regulatory element. | although changes in gene regulation may play an important role in adaptive evolution, there have been few attempts to investigate the molecular mechanisms responsible for adaptively significant variation in gene expression. here we describe the mechanism underlying an adaptive difference in the expression of the lactate dehydrogenase-b gene (ldh-b) between northern and southern populations of the fish fundulus heteroclitus. ldh-b regulatory sequences from northern and southern individuals, coupl ... | 2000 | 10841559 |
| [the gene of human prion: reassessment of its features and pathogenic role]. | after a detailed examination of some features of the human prion gene, we propose a reassessment of its role in the pathogenicity of the derived neurodegenerative diseases e.g. creutzfeldt-jakob's disease. the particular resistance of this gene towards physico-chemical agents is related to the relative abundance of the guanine and cytosine bases. other features such as the paucity of cpg sequences, gc box, polyadenylic tail, direct and inverted repeats, all evoke those of retroviral ltrs. finall ... | 2000 | 10844280 |
| transcriptionally regulated adenoviruses for prostate-specific gene therapy. | most virally based vectors for gene therapy contain viral promoters that are tissue-nonspecific. consequently, unintended expression of toxic therapeutic genes in normal tissues may potentially occur. we have constructed adenoviruses that contain a bacterial beta-galactosidase (beta-gal) gene (lacz) under the control of three different prostate-specific promoters: prostate-specific antigen (psa), probasin, and the mouse mammary-tumor-virus long terminal repeat (mmtv; prostate-specific ad-lacz). ... | 2000 | 10854143 |
| p185(neu) protein is required for tumor and anchorage-independent growth, not for cell proliferation of transgenic mammary carcinoma. | transgenic fvb-neun mice (n202) bearing the rat neu protooncogene driven by the mouse mammary tumor virus promoter/enhancer develop focal mammary carcinomas overexpressing the neu-encoded p185(neu) protein. in vitro expression of p185(neu) among mammary carcinoma cultures was heterogeneous, and we could establish some cell lines and clones displaying a complete loss of p185(neu) expression, along with others with very high p185(neu) protein level. upon in vivo injection, p185(neu)-positive cells ... | 2000 | 10861472 |
| cdp is a repressor of mouse mammary tumor virus expression in the mammary gland. | mouse mammary tumor virus (mmtv) transcription is highest in the lactating mammary gland but is detectable in a variety of other tissues. previous results have shown that mmtv expression is suppressed in lymphoid and other tissues through the binding of the homeodomain-containing repressor special at-rich binding protein 1 to a negative regulatory element (nre) in the mmtv long terminal repeat (ltr). another homeoprotein repressor, ccaat displacement protein (cdp), also binds to the mmtv nre, bu ... | 2000 | 10864645 |
| functional analysis of the env open reading frame in human endogenous retrovirus iddmk(1,2)22 encoding superantigen activity. | mice harbor a family of endogenous retroviruses, the mouse mammary tumor viruses (mmtv), which encode superantigens. these superantigens are responsible for the deletion of t cells expressing certain vbeta chains of the t-cell receptor in the thymus. human t cells are able to recognize mmtv-encoded superantigens presented by human major histocompatibility complex class ii-positive cells. owing to this and to the similarity of the human and murine immune systems, it was speculated that human endo ... | 2000 | 10864649 |
| gene switching: analyzing a broad range of mutations using steric block antisense oligonucleotides. | 2000 | 10595356 | |
| engineering cho cells to overexpress a secreted reporter protein upon induction from mouse mammary tumor virus promoter. | the mouse mammary tumor virus (mmtv) promoter is induced by the addition of a glucocorticoid hormone or analog such as dexamethasone. the hormone binds to its specific transcription factor, glucocorticoid receptor (gr), and the activated complex then binds to the glucocorticoid response elements (gres) in the enhancer region of the mmtv promoter to induce the overexpression of downstream genes. we have constructed an expression vector for a reporter protein, secreted alkaline phosphatase (seap), ... | 2000 | 10592510 |