1
|
Distribution of lentiviral vector integration sites in mice following therapeutic gene transfer to treat β-thalassemia. Mol Ther 2011; 19:1273-86. [PMID: 21386821 DOI: 10.1038/mt.2011.20] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
A lentiviral vector encoding β-globin flanked by insulator elements has been used to treat β-thalassemia (β-Thal) successfully in one human subject. However, a clonal expansion was observed after integration in the HMGA2 locus, raising the question of how commonly lentiviral integration would be associated with possible insertional activation. Here, we report correcting β-Thal in a murine model using the same vector and a busulfan-conditioning regimen, allowing us to investigate efficacy and clonal evolution at 9.2 months after transplantation of bone marrow cells. The five gene-corrected recipient mice showed near normal levels of hemoglobin, reduced accumulation of reticulocytes, and normalization of spleen weights. Mapping of integration sites pretransplantation showed the expected favored integration in transcription units. The numbers of gene-corrected long-term repopulating cells deduced from the numbers of unique integrants indicated oligoclonal reconstitution. Clonal abundance was quantified using a Mu transposon-mediated method, indicating that clones with integration sites near growth-control genes were not enriched during growth. No integration sites involving HMGA2 were detected. Cells containing integration sites in genes became less common after prolonged growth, suggesting negative selection. Thus, β-Thal gene correction in mice can be achieved without expansion of cells harboring vectors integrated near genes involved in growth control.
Collapse
|
2
|
Loss of MicroRNA targets in the 3' untranslated region as a mechanism of retroviral insertional activation of growth factor independence 1. J Virol 2009; 83:8051-61. [PMID: 19474094 DOI: 10.1128/jvi.00427-09] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The non-oncogene-bearing retrovirus SL3-3 murine leukemia virus induces strictly T-cell lymphomas with a mean latency of 2 to 4 months in mice of the NMRI-inbred (NMRI-i) strain. By high-throughput sequencing of retroviral tags, we have identified the genomic region carrying the transcriptional repressor and oncogene growth factor independence 1 (Gfi1) as a frequent target for SL3-3 in the NMRI-i mouse genome. Twenty-four SL3-3 insertions were identified within a 1-kb window of the 3' untranslated region (3'UTR) of the Gfi1 gene, a clustering pattern unique for this lymphoma model. Expression analysis determined that the Gfi1 gene was transcriptionally activated by SL3-3 insertions, and an upregulation of Gfi1 protein expression was detected for tumors harboring insertions in the Gfi1 3'UTR. Here we provide data in support of a mechanism by which retroviral insertions in the Gfi1 3'UTR decouple microRNA-mediated posttranscriptional regulation.
Collapse
|
3
|
Popken-Harris P, Kirchhof N, Harrison B, Harris LF. Gene expression array analyses predict increased proto-oncogene expression in MMTV induced mammary tumors. Virus Res 2006; 119:177-86. [PMID: 16469401 DOI: 10.1016/j.virusres.2006.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/01/2006] [Indexed: 11/28/2022]
Abstract
Exogenous infection by milk-borne mouse mammary tumor viruses (MMTV) typically induce mouse mammary tumors in genetically susceptible mice at a rate of 90-95% by 1 year of age. In contrast to other transforming retroviruses, MMTV acts as an insertional mutagen and under the influence of steroid hormones induces oncogenic transformation after insertion into the host genome. As these events correspond with increases in adjacent proto-oncogene transcription, we used expression array profiling to determine which commonly associated MMTV insertion site proto-oncogenes were transcriptionally active in MMTV induced mouse mammary tumors. To verify our gene expression array results we developed real-time quantitative RT-PCR assays for the common MMTV insertion site genes found in RIII/Sa mice (int-1/wnt-1, int-2/fgf-3, int-3/Notch 4, and fgf8/AIGF) as well as two genes that were consistently up regulated (CCND1, and MAT-8) and two genes that were consistently down regulated (FN1 and MAT-8) in the MMTV induced tumors as compared to normal mammary gland. Finally, each tumor was also examined histopathologically. Our expression array findings support a model whereby just one or a few common MMTV insertions into the host genome sets up a dominant cascade of events that leave a characteristic molecular signature.
Collapse
Affiliation(s)
- Pamela Popken-Harris
- David F. Hickok Memorial Cancer Research Laboratory, Abbott Northwestern Hospital, Mpls., MN 54407, USA.
| | | | | | | |
Collapse
|
4
|
Zhu Q, Gregg K, Lozano M, Liu J, Dudley JP. CDP is a repressor of mouse mammary tumor virus expression in the mammary gland. J Virol 2000; 74:6348-57. [PMID: 10864645 PMCID: PMC112141 DOI: 10.1128/jvi.74.14.6348-6357.2000] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2000] [Accepted: 04/19/2000] [Indexed: 01/19/2023] Open
Abstract
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, but a role for CDP in MMTV transcriptional suppression has not yet been demonstrated. In this paper, we show that the level of CDP decreases during development of the mammary gland and that this decline in CDP level correlates with the known increase in MMTV expression observed during mammary gland differentiation. Moreover, CDP overexpression was able to suppress MMTV LTR-reporter gene activity up to 20-fold in transient-transfection assays of mouse mammary cells. To determine if this effect was due to direct binding of CDP to the promoter-proximal NRE, we performed DNase I protection assays to map two CDP-binding sites from +835 to +845 and +920 to +931 relative to the first base of the LTR. Mutations engineered into each of these sites decreased CDP binding to the proximal NRE, whereas a combination of these mutations further reduced binding. Subsequently, each of these mutations was introduced into the full-length MMTV LTR upstream of the luciferase reporter gene. Analysis of stable transfectants of LTR constructs showed that CDP binding site mutations in the proximal NRE elevated reporter gene expression two- to sixfold compared to wild-type LTR constructs. Thus, MMTV expression increases during mammary gland development, in part due to decreased CDP levels and CDP binding to the LTR. Together, these experiments provide the first evidence that CDP acts as a repressor of MMTV transcription in the mammary gland.
Collapse
MESH Headings
- Animals
- Cells, Cultured
- DNA Footprinting
- DNA, Viral/genetics
- DNA, Viral/physiology
- Deoxyribonuclease I
- Female
- Gene Expression Regulation
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- Mammary Glands, Animal/cytology
- Mammary Glands, Animal/growth & development
- Mammary Glands, Animal/metabolism
- Mammary Glands, Animal/virology
- Mammary Tumor Virus, Mouse/genetics
- Mammary Tumor Virus, Mouse/metabolism
- Mice
- Mice, Inbred BALB C
- Mutagenesis
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Protein Binding
- Repressor Proteins/genetics
- Repressor Proteins/metabolism
- Terminal Repeat Sequences
Collapse
Affiliation(s)
- Q Zhu
- Section of Molecular Genetics and Microbiology and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78705, USA
| | | | | | | | | |
Collapse
|
5
|
Abstract
Integration of mouse mammary tumor virus (MMTV) near the int genes results in the inappropriate expression of these proto-oncogenes and initiates events that lead to the formation of mammary adenocarcinomas. In most cases, the MMTV provirus integrates in a transcriptional orientation opposite that of the int genes. We have used a novel, vector-based system designed to recapitulate the integration of MMTV upstream of the int-2 promoter. Compared to a cellular promoter or another retroviral promoter, the MMTV long terminal repeat (LTR) in this configuration is particularly efficacious at activating the int-2 promoter. The sequences responsible for enhancing the activity of the int-2 promoter map to two domains in the 5' end of the MMTV LTR. One domain is a previously defined element; the second is an element delineated by these studies that acts synergistically with the first. Both of these elements display mammary cell-specific activity. Thus, even though the MMTV promoter itself is weak without hormonal stimulation, viral integration can position the 5' LTR elements to efficiently activate transcription from cellular proto-oncogenes. Other functional elements in the LTR have little effect on the activation of the int-2 promoter. Even stimulation of the MMTV promoter with steroid hormones only modestly activates transcription from the int-2 promoter, suggesting that the 5' elements of the LTR are the predominant determinants of the tissue- and orientation-specific activation of cellular promoters by MMTV.
Collapse
Affiliation(s)
- S L Grimm
- Program in Molecular Biology, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA
| | | |
Collapse
|
6
|
Rynditch AV, Zoubak S, Tsyba L, Tryapitsina-Guley N, Bernardi G. The regional integration of retroviral sequences into the mosaic genomes of mammals. Gene 1998; 222:1-16. [PMID: 9813219 DOI: 10.1016/s0378-1119(98)00451-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We have reviewed here three sets of data concerning the integration of retroviral sequences in the mammalian genome: (i) our experimental localization of a number of proviruses integrated in isochores characterized by different GC levels; (ii) results from other laboratories on the localization of retroviral sequences in open chromatin regions and/or next to CpG islands; and (iii) our compositional analysis of genes located in the neighborhood of integrated retroviral sequences. The three sets of data have provided a very consistent picture in that a compartmentalized, isopycnic integration of expressed proviruses appears to be the rule ('isopycnic' refers to the compositional match between viral and host sequences around the integration site). The results reviewed here suggest that: (i) integration of proviral sequences is targeted initially towards 'open chromatin regions'; while these exist in both GC-rich and GC-poor isochores, the 'open chromatin regions' of GC-rich isochores are the main targets for integration of retroviral sequences because of their much greater abundance; (ii) isopycnicity is associated with stability of integration; indeed, even non-expressed integrated retroviral sequences tend to show an isopycnic localization in the genome; (iii) transcription of integrated viral sequences (like transcription of host genes) appears to be associated, as a rule, with an isopycnic localization, as indicated by transcribed sequences that show an isopycnic integration and act in trans; (iv) selection plays a role in the choice of specific sites within an isopycnic region; in exceptional cases [such as mouse mammary tumor virus (MMTV) activating GC-rich oncogenes], selection may override isopycnicity.
Collapse
Affiliation(s)
- A V Rynditch
- Laboratoire de Génétique Moléculaire, Institut Jacques Monod, 2 Place Jussieu, 75005, Paris, France
| | | | | | | | | |
Collapse
|
7
|
Carlton MB, Colledge WH, Evans MJ. Crouzon-like craniofacial dysmorphology in the mouse is caused by an insertional mutation at the Fgf3/Fgf4 locus. Dev Dyn 1998; 212:242-9. [PMID: 9626498 DOI: 10.1002/(sici)1097-0177(199806)212:2<242::aid-aja8>3.0.co;2-h] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Retroviral insertional mutagenesis by means of ES cells has resulted in a new autosomal dominant mutation causing craniofacial dysmorphology in the mouse (Bulgy-eye, Bey). Heterozygous Bey mice are viable and fertile but show facial shortening with increased interorbital distance and precocious closure of several cranial sutures (craniosynostosis). These features provide a murine phenocopy for a large class of human craniofacial dysmorphology syndromes associated with craniosynostosis, particularly Crouzon syndrome. The retroviral vector integration responsible for the Bey mutation is inserted in the intragenic region between Fgf3 and Fgf4. Transcript analysis demonstrates that expression of both Fgf3 and Fgf4 is up-regulated in the cranial sutures of Bey mice. Many of these human craniosynostosis syndromes are caused by mutations in the extracellular domain of receptors for fibroblast growth factors that result in constitutive receptor activation. Our data confirm that fibroblast growth factor signalling pathways are involved in craniofacial development and suggest that some human malformation pedigrees or sporadic craniosynostosis may be caused by mutations that deregulate expression of the Fgf ligands.
Collapse
Affiliation(s)
- M B Carlton
- Wellcome Trust, Cancer Research Campaign, Institute of Cancer, University of Cambridge, United Kingdom.
| | | | | |
Collapse
|
8
|
Morris DW, Dutra JC. Identification of a MMTV insertion mutation within the coding region of the Fgf-3 protooncogene. Virology 1997; 238:161-5. [PMID: 9375020 DOI: 10.1006/viro.1997.8794] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The Fgf-3 protooncogene (previously called int-2) is a target of proviral insertion mutations in mammary tumors induced by the mouse mammary tumor virus (MMTV). These insertion mutations result in the transcriptional activation of Fgf-3, which is not normally expressed in the adult mammary gland. Previous mapping studies of numerous Fgf-3 insertion mutations have failed to reveal any provirus integrations within the gene coding region. This finding is consistent with the hypothesis that oncogenesis occurs in this system as a consequence of up-regulation of Fgf-3 transcription, rather than from alterations of the gene product. During an analysis of a new cohort of tumors from the WXG-2 mouse strain, a breast tumor was identified which had a MMTV provirus integrated 24 bp upstream of the Fgf-3 stop codon. This insertion mutation generated a fusion transcript which was readily detectable in tumor RNA by RT-PCR. The predicted protein product of this fusion transcript is missing 8 aa of native sequence and contains an additional 8 aa of cryptic MMTV-encoded sequence. These data document the first exception to the generalization that the Fgf-3 coding region is not disrupted by MMTV insertion mutation.
Collapse
Affiliation(s)
- D W Morris
- Department of Medical Pathology, University of California, Davis 95616, USA.
| | | |
Collapse
|
9
|
|
10
|
Jonkers J, Berns A. Retroviral insertional mutagenesis as a strategy to identify cancer genes. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1287:29-57. [PMID: 8639705 DOI: 10.1016/0304-419x(95)00020-g] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- J Jonkers
- The Netherlands Cancer Institute, Division of Molecular Genetics, Amsterdam, Netherlands
| | | |
Collapse
|
11
|
Durgam VR, Easton JA, Surya R, Tekmal RR. Structure of the int-5, a novel MMTV integration genomic locus containing mouse early transposon LTR homology region. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1263:89-92. [PMID: 7632740 DOI: 10.1016/0167-4781(95)00093-v] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Previous studies have reported the cloning and identification of the int-5, a novel mouse mammary tumor virus (MMTV) integration locus involved in mammary tumorigenesis. Here we report the characterization of the 5.5 kb region from this novel MMTV integration site. Our results show that the region after the MMTV integration site, a 258 bp sequence is homologous (100%) to the mouse early transposon (mETn) long-terminal repeat and other sequences of the this transposon are not present in the 5.5 kb region. Our results also show for the first time the tumor specific expression of mETn and expression of the region downstream of the MMTV integration site that is homologous to mETn-LTR in D2 mammary tumors.
Collapse
Affiliation(s)
- V R Durgam
- Department of Obstetrics and Gynecology, University of Texas Health Science Center at San Antonio 78284-7836, USA
| | | | | | | |
Collapse
|
12
|
Activation of the mouse mdr3 gene by insertion of retroviruses in multidrug-resistant P388 tumor cells. Mol Cell Biol 1994. [PMID: 8246958 DOI: 10.1128/mcb.13.12.7380] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In multidrug-resistant (MDR) derivatives of the mouse lymphoid tumor P388, the emergence of MDR is associated with overexpression and transcriptional activation of the mdr3 gene, either in the absence of (P388/VCR-10) or concomitant with (P388/ADM-2) gene amplification. In both instances, Northern (RNA) blotting analyses have suggested the presence of altered mdr3 transcripts in these cells, possibly originating from novel transcription initiation sites. The mechanisms underlying mdr3 overexpression in these cells have been investigated. In P388/VCR-10 cells, Southern blotting analyses together with genomic DNA cloning and nucleotide sequencing have demonstrated the presence of an intact mouse mammary tumor virus (MMTV) within the boundaries of intron 1 of mdr3. cDNA cloning and nucleotide sequencing indicated that this integration event results in the synthesis and overexpression of a hybrid MMTV-mdr3 mRNA which initiates within the U3 region of the 5' long terminal repeat (LTR) of the provirus. Consequently, this mRNA lacks the normal exon 1 of mdr3 but contains (i) MMTV LTR-derived sequences at its 5' end, (ii) a novel mdr3 exon, mapping within the boundaries of intron 1 downstream of the MMTV integration site and generated by alternative splicing, and (iii) an otherwise intact 3' portion of mdr3 starting at exon 2. A similar type of analysis of P388/ADM-2 cells revealed that mdr3 overexpression in these cells is associated with the integration of an intracisternal A particle (IAP) within an L1Md repetitive element, immediately upstream of mdr3. The IAP insertion results in the overexpression of hybrid IAP-mdr3 mRNA transcripts that initiate within the 3' LTR of the IAP and which contain IAP LTR-derived sequences at the 5' end spliced 14 nucleotides upstream of the normal exon 1 of mdr3. Taken together, these results indicate that independent retroviral insertions were the initial mutagenic event responsible for mdr3 overexpression and survival during drug selection of these cell lines. Amplification of the rearranged and activated mdr3 gene copy occurred during further selection for high-level drug resistance in P388/ADM-2 cells.
Collapse
|
13
|
Abstract
The site of basic fibroblast growth factor (bFGF) gene expression in human placenta is not known. In situ hybridization using [35S]-labelled riboprobe was employed to localize the sites of expression of bFGF mRNA in placental sections from early and late gestation. Autoradiographic hybridization signal was present in all placental tissue examined, with no significant hybridization with sense control. Basic FGF expression was seen in the syncytiotrophoblast surrounding the placental villi and in or around cytotrophoblast cells in first trimester placenta. At term, the bFGF gene expression was detected in the syncytiotrophoblast and fetal membranes. Strong expression of bFGF mRNA was localized in the smooth muscle cells around the mid and large sized placental vessels. The detection of bFGF mRNA in the placenta during early pregnancy suggests a role for bFGF in angiogenesis, whereas, its expression at term suggests that bFGF may be associated with differentiated functions of the trophoblast.
Collapse
Affiliation(s)
- M Shams
- Centre for Clinical Research in Immunology and Signalling (CCRIS), Medical School, University of Birmingham, Edgbaston, UK
| | | |
Collapse
|
14
|
Lepage P, Devault A, Gros P. Activation of the mouse mdr3 gene by insertion of retroviruses in multidrug-resistant P388 tumor cells. Mol Cell Biol 1993; 13:7380-92. [PMID: 8246958 PMCID: PMC364809 DOI: 10.1128/mcb.13.12.7380-7392.1993] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In multidrug-resistant (MDR) derivatives of the mouse lymphoid tumor P388, the emergence of MDR is associated with overexpression and transcriptional activation of the mdr3 gene, either in the absence of (P388/VCR-10) or concomitant with (P388/ADM-2) gene amplification. In both instances, Northern (RNA) blotting analyses have suggested the presence of altered mdr3 transcripts in these cells, possibly originating from novel transcription initiation sites. The mechanisms underlying mdr3 overexpression in these cells have been investigated. In P388/VCR-10 cells, Southern blotting analyses together with genomic DNA cloning and nucleotide sequencing have demonstrated the presence of an intact mouse mammary tumor virus (MMTV) within the boundaries of intron 1 of mdr3. cDNA cloning and nucleotide sequencing indicated that this integration event results in the synthesis and overexpression of a hybrid MMTV-mdr3 mRNA which initiates within the U3 region of the 5' long terminal repeat (LTR) of the provirus. Consequently, this mRNA lacks the normal exon 1 of mdr3 but contains (i) MMTV LTR-derived sequences at its 5' end, (ii) a novel mdr3 exon, mapping within the boundaries of intron 1 downstream of the MMTV integration site and generated by alternative splicing, and (iii) an otherwise intact 3' portion of mdr3 starting at exon 2. A similar type of analysis of P388/ADM-2 cells revealed that mdr3 overexpression in these cells is associated with the integration of an intracisternal A particle (IAP) within an L1Md repetitive element, immediately upstream of mdr3. The IAP insertion results in the overexpression of hybrid IAP-mdr3 mRNA transcripts that initiate within the 3' LTR of the IAP and which contain IAP LTR-derived sequences at the 5' end spliced 14 nucleotides upstream of the normal exon 1 of mdr3. Taken together, these results indicate that independent retroviral insertions were the initial mutagenic event responsible for mdr3 overexpression and survival during drug selection of these cell lines. Amplification of the rearranged and activated mdr3 gene copy occurred during further selection for high-level drug resistance in P388/ADM-2 cells.
Collapse
Affiliation(s)
- P Lepage
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
| | | | | |
Collapse
|
15
|
|
16
|
Brigle K, Westin E, Houghton M, Goldman I. Insertion of an intracisternal A particle within the 5'-regulatory region of a gene encoding folate-binding protein in L1210 leukemia cells in response to low folate selection. Association with increased protein expression. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)41678-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
|
17
|
Transgenes expressing the Wnt-1 and int-2 proto-oncogenes cooperate during mammary carcinogenesis in doubly transgenic mice. Mol Cell Biol 1992. [PMID: 1530875 DOI: 10.1128/mcb.12.1.147] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Wnt-1 and int-2 proto-oncogenes are transcriptionally activated by mouse mammary tumor virus insertion mutations in virus-induced tumors and encode secretory glycoproteins. To determine whether these two genes can cooperate during carcinogenesis, we have crossed two previously characterized lines of transgenic mice to obtain bitransgenic animals carrying both Wnt-1 and int-2 transgenes under the control of the mouse mammary tumor virus long terminal repeat. Mammary carcinomas appear earlier and with higher frequency in the bitransgenic animals, especially the males, than in either parental line. Nearly all bitransgenic males develop mammary neoplasms within 8 months of birth, whereas only 15% of Wnt-1 transgenic males and none of the int-2 transgenic males have tumors. In virgin bitransgenic females, tumors occur approximately 2 months earlier than in their Wnt-1 transgenic siblings; int-2 transgenic females rarely exhibit tumors. Preneoplastic glands from the bitransgenic animals of either sex demonstrate pronounced epithelial hyperplasia similar to that seen in Wnt-1 transgenic virgin females and males, and both transgenes are expressed in the hyperplastic glands and mammary tumors. RNA from the int-2 transgene is more abundant in mammary glands from bitransgenic animals than from int-2 transgenic animals; the increase is associated with high levels of RNA specific for keratin genes 14 and 18, suggesting that Wnt-1-induced epithelial hyperplasia is responsible for the observed increase in expression of the int-2 transgene.
Collapse
|
18
|
Kwan H, Pecenka V, Tsukamoto A, Parslow TG, Guzman R, Lin TP, Muller WJ, Lee FS, Leder P, Varmus HE. Transgenes expressing the Wnt-1 and int-2 proto-oncogenes cooperate during mammary carcinogenesis in doubly transgenic mice. Mol Cell Biol 1992; 12:147-54. [PMID: 1530875 PMCID: PMC364078 DOI: 10.1128/mcb.12.1.147-154.1992] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The Wnt-1 and int-2 proto-oncogenes are transcriptionally activated by mouse mammary tumor virus insertion mutations in virus-induced tumors and encode secretory glycoproteins. To determine whether these two genes can cooperate during carcinogenesis, we have crossed two previously characterized lines of transgenic mice to obtain bitransgenic animals carrying both Wnt-1 and int-2 transgenes under the control of the mouse mammary tumor virus long terminal repeat. Mammary carcinomas appear earlier and with higher frequency in the bitransgenic animals, especially the males, than in either parental line. Nearly all bitransgenic males develop mammary neoplasms within 8 months of birth, whereas only 15% of Wnt-1 transgenic males and none of the int-2 transgenic males have tumors. In virgin bitransgenic females, tumors occur approximately 2 months earlier than in their Wnt-1 transgenic siblings; int-2 transgenic females rarely exhibit tumors. Preneoplastic glands from the bitransgenic animals of either sex demonstrate pronounced epithelial hyperplasia similar to that seen in Wnt-1 transgenic virgin females and males, and both transgenes are expressed in the hyperplastic glands and mammary tumors. RNA from the int-2 transgene is more abundant in mammary glands from bitransgenic animals than from int-2 transgenic animals; the increase is associated with high levels of RNA specific for keratin genes 14 and 18, suggesting that Wnt-1-induced epithelial hyperplasia is responsible for the observed increase in expression of the int-2 transgene.
Collapse
Affiliation(s)
- H Kwan
- Department of Microbiology and Immunology, University of California, San Francisco 94143
| | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
|
20
|
Two regions of the mouse mammary tumor virus long terminal repeat regulate the activity of its promoter in mammary cell lines. Mol Cell Biol 1991. [PMID: 1708094 DOI: 10.1128/mcb.11.5.2529] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In vivo expression of the mouse mammary tumor virus (MMTV) is restricted to a few organs, with the highest rate of transcription found in the mammary gland. Using a series of mammary and nonmammary murine cell lines, we have identified two regulatory elements, located upstream of the hormone responsive element, that specifically regulate the MMTV promoter. The first element displays an enhancerlike activity and is coincident with the binding of a nuclear factor (designated MP4; position -1078 to -1052 in the long terminal repeat) whose presence is apparently restricted to mammary cell lines. The second regulatory region mediates a repressive activity and is mapped to the long terminal repeat segment from -415 to -483. This repression is specific for a particular subtype of mammary cells (RAC cells) able to grow under two differentiation states (A. Sonnenberg, H. Daams, J. Calafat, and J. Hilgers, Cancer Res. 46:5913-5922, 1986). The MMTV promoter in mammary cell lines thus appears to be modulated by two cis-acting elements that are likely to be involved in tissue-specific expression in vivo.
Collapse
|
21
|
Lefebvre P, Berard DS, Cordingley MG, Hager GL. Two regions of the mouse mammary tumor virus long terminal repeat regulate the activity of its promoter in mammary cell lines. Mol Cell Biol 1991; 11:2529-37. [PMID: 1708094 PMCID: PMC360022 DOI: 10.1128/mcb.11.5.2529-2537.1991] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
In vivo expression of the mouse mammary tumor virus (MMTV) is restricted to a few organs, with the highest rate of transcription found in the mammary gland. Using a series of mammary and nonmammary murine cell lines, we have identified two regulatory elements, located upstream of the hormone responsive element, that specifically regulate the MMTV promoter. The first element displays an enhancerlike activity and is coincident with the binding of a nuclear factor (designated MP4; position -1078 to -1052 in the long terminal repeat) whose presence is apparently restricted to mammary cell lines. The second regulatory region mediates a repressive activity and is mapped to the long terminal repeat segment from -415 to -483. This repression is specific for a particular subtype of mammary cells (RAC cells) able to grow under two differentiation states (A. Sonnenberg, H. Daams, J. Calafat, and J. Hilgers, Cancer Res. 46:5913-5922, 1986). The MMTV promoter in mammary cell lines thus appears to be modulated by two cis-acting elements that are likely to be involved in tissue-specific expression in vivo.
Collapse
Affiliation(s)
- P Lefebvre
- Hormone Action and Oncogenesis Section, National Cancer Institute Bethesda, Maryland 20892
| | | | | | | |
Collapse
|
22
|
Van de Vijver MJ, Nusse R. The molecular biology of breast cancer. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1072:33-50. [PMID: 2018777 DOI: 10.1016/0304-419x(91)90005-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- M J Van de Vijver
- Division of Molecular Biology, The Netherlands Cancer Institute, Amsterdam
| | | |
Collapse
|
23
|
MESH Headings
- Amino Acid Sequence
- Animals
- Breast Neoplasms/genetics
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Viral
- Drosophila Proteins
- Drosophila melanogaster/embryology
- Drosophila melanogaster/genetics
- Embryonic and Fetal Development/genetics
- Enhancer Elements, Genetic
- Female
- Fibroblast Growth Factor 3
- Fibroblast Growth Factor 4
- Fibroblast Growth Factors/genetics
- Gene Expression Regulation, Neoplastic
- Gene Expression Regulation, Viral
- Humans
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/microbiology
- Mammary Tumor Virus, Mouse/genetics
- Mice/embryology
- Mice/genetics
- Mice, Transgenic
- Molecular Sequence Data
- Multigene Family
- Mutagenesis, Insertional
- Neoplasm Proteins/genetics
- Neoplasm Proteins/physiology
- Oncogenes
- Proteins/genetics
- Proto-Oncogene Proteins/biosynthesis
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/physiology
- Proviruses/genetics
- Sequence Homology, Nucleic Acid
- Species Specificity
- Virus Integration
- Wnt Proteins
- Wnt1 Protein
- Wnt3 Protein
- Zebrafish Proteins
Collapse
Affiliation(s)
- R Nusse
- Howard Hughes Medical Institute, Stanford, CA
| |
Collapse
|
24
|
Kung HJ, Boerkoel C, Carter TH. Retroviral mutagenesis of cellular oncogenes: a review with insights into the mechanisms of insertional activation. Curr Top Microbiol Immunol 1991; 171:1-25. [PMID: 1814689 DOI: 10.1007/978-3-642-76524-7_1] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- H J Kung
- Department of Molecular Biology and Microbiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106
| | | | | |
Collapse
|