1
|
Affiliation(s)
- K J Cremer
- Biological Carcinogenesis Branch, National Cancer Institute, Bethesda, MD 20892
| | | |
Collapse
|
2
|
Abstract
The integration of a DNA copy of the viral RNA genome into host chromatin is the defining step of retroviral replication. This enzymatic process is catalyzed by the virus-encoded integrase protein, which is conserved among retroviruses and LTR-retrotransposons. Retroviral integration proceeds via two integrase activities: 3'-processing of the viral DNA ends, followed by the strand transfer of the processed ends into host cell chromosomal DNA. Herein we review the molecular mechanism of retroviral DNA integration, with an emphasis on reaction chemistries and architectures of the nucleoprotein complexes involved. We additionally discuss the latest advances on anti-integrase drug development for the treatment of AIDS and the utility of integrating retroviral vectors in gene therapy applications.
Collapse
Affiliation(s)
- Paul Lesbats
- Clare Hall Laboratories, The Francis Crick Institute , Blanche Lane, South Mimms, EN6 3LD, U.K
| | - Alan N Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School , 450 Brookline Avenue, Boston, Massachusetts 02215 United States
| | - Peter Cherepanov
- Clare Hall Laboratories, The Francis Crick Institute , Blanche Lane, South Mimms, EN6 3LD, U.K.,Imperial College London , St-Mary's Campus, Norfolk Place, London, W2 1PG, U.K
| |
Collapse
|
3
|
Nicot C. HTLV-I Tax-Mediated Inactivation of Cell Cycle Checkpoints and DNA Repair Pathways Contribute to Cellular Transformation: "A Random Mutagenesis Model". ACTA ACUST UNITED AC 2015; 2. [PMID: 26835512 DOI: 10.13188/2377-9292.1000009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
To achieve cellular transformation, most oncogenic retroviruses use transduction by proto-oncogene capture or insertional mutagenesis, whereby provirus integration disrupts expression of tumor suppressors or proto-oncogenes. In contrast, the Human T-cell leukemia virus type 1 (HTLV-I) has been classified in a separate class referred to as "transactivating retroviruses". Current views suggest that the viral encoded Tax protein transactivates expression of cellular genes leading to deregulated growth and transformation. However, if Tax-mediated transactivation was indeed sufficient for cellular transformation, a fairly high frequency of infected cells would eventually become transformed. In contrast, the frequency of transformation by HTLV-I is very low, likely less than 5%. This review will discuss the current understanding and recent discoveries highlighting critical functions of Tax in cellular transformation. HTLV-I Tax carries out essential functions in order to override cell cycle checkpoints and deregulate cellular division. In addition, Tax expression is associated with increased DNA damage and genome instability. Since Tax can inhibit multiple DNA repair pathways and stimulate unfaithful DNA repair or bypass checkpoints, these processes allow accumulation of genetic mutations in the host genome. Given this, a "Random Mutagenesis" transformation model seems more suitable to characterize the oncogenic activities of HTLV-I.
Collapse
Affiliation(s)
- Christophe Nicot
- Department of Pathology and Laboratory Medicine, Center for Viral Oncology, University of Kansas Medical Center, USA
| |
Collapse
|
4
|
Abstract
Retroviruses are the original source of oncogenes. The discovery and characterization of these genes was made possible by the introduction of quantitative cell biological and molecular techniques for the study of tumour viruses. Key features of all retroviral oncogenes were first identified in src, the oncogene of Rous sarcoma virus. These include non-involvement in viral replication, coding for a single protein and cellular origin. The MYC, RAS and ERBB oncogenes quickly followed SRC, and these together with PI3K are now recognized as crucial driving forces in human cancer.
Collapse
Affiliation(s)
- Peter K Vogt
- The Scripps Research Institute, La Jolla, California 92037, USA.
| |
Collapse
|
5
|
Rebollo R, Romanish MT, Mager DL. Transposable elements: an abundant and natural source of regulatory sequences for host genes. Annu Rev Genet 2012; 46:21-42. [PMID: 22905872 DOI: 10.1146/annurev-genet-110711-155621] [Citation(s) in RCA: 352] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The fact that transposable elements (TEs) can influence host gene expression was first recognized more than 50 years ago. However, since that time, TEs have been widely regarded as harmful genetic parasites-selfish elements that are rarely co-opted by the genome to serve a beneficial role. Here, we survey recent findings that relate to TE impact on host genes and remind the reader that TEs, in contrast to other noncoding parts of the genome, are uniquely suited to gene regulatory functions. We review recent studies that demonstrate the role of TEs in establishing and rewiring gene regulatory networks and discuss the overall ubiquity of exaptation. We suggest that although individuals within a population can be harmed by the deleterious effects of new TE insertions, the presence of TE sequences in a genome is of overall benefit to the population.
Collapse
Affiliation(s)
- Rita Rebollo
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada.
| | | | | |
Collapse
|
6
|
Wang Y, Liska F, Gosele C, Sedová L, Kren V, Krenová D, Ivics Z, Hubner N, Izsvák Z. A novel active endogenous retrovirus family contributes to genome variability in rat inbred strains. Genome Res 2009; 20:19-27. [PMID: 19887576 DOI: 10.1101/gr.100073.109] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Endogenous retroviruses (ERVs) contribute to a range of germline, as well as somatic mutations in mammals. However, autonomous retrotransposition of potentially active elements has not been demonstrated in the rat genome. We cloned an insertion that disrupted the normal splicing of the Cntrob gene that was subsequently identified as a nonautonomous, novel endogenous retrovirus of the RnERV-K8e family. The RnERV-K8e family is closely related to the recently reported MmERV-K10c elements, but differs from the autonomous mouse MusD or IAP families. In addition, we identified a novel, unexpectedly close relative of RnERV-K8e in the mouse, suggesting ERV-K cross-species transmission between mice and rats. We cloned a potentially autonomous RnERV-K8e element identified by in silico analysis and, using an in vitro retrotransposition assay, demonstrated that it is capable of retrotransposition. This particular element (named Rat-rho, pronounced "retro") encodes a retroviral envelope gene (env); however, env is not required for de novo retrotransposition events. Significant levels of RnERV-K8e-associated genetic polymorphisms were detected among inbred rat strains, suggesting ongoing retrotransposition in the rat genome. This study identifies an ERV-K-type family in rats that shows obvious signs of recent activity. Ongoing retrotranspositional activity may significantly add to genomic variability among inbred rat strains.
Collapse
Affiliation(s)
- Yongming Wang
- Max-Delbrück-Center for Molecular Medicine (MDC), Berlin, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Genome-wide assessments reveal extremely high levels of polymorphism of two active families of mouse endogenous retroviral elements. PLoS Genet 2008; 4:e1000007. [PMID: 18454193 PMCID: PMC2265474 DOI: 10.1371/journal.pgen.1000007] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Accepted: 01/15/2008] [Indexed: 11/19/2022] Open
Abstract
Endogenous retroviral elements (ERVs) in mice are significant genomic mutagens, causing ∼10% of all reported spontaneous germ line mutations in laboratory strains. The majority of these mutations are due to insertions of two high copy ERV families, the IAP and ETn/MusD elements. This significant level of ongoing retrotranspositional activity suggests that inbred mice are highly variable in content of these two ERV groups. However, no comprehensive genome-wide studies have been performed to assess their level of polymorphism. Here we compared three test strains, for which sufficient genomic sequence is available, to each other and to the reference C57BL/6J genome and detected very high levels of insertional polymorphism for both ERV families, with an estimated false discovery rate of only 0.4%. Specifically, we found that at least 60% of IAP and 25% of ETn/MusD elements detected in any strain are absent in one or more of the other three strains. The polymorphic nature of a set of 40 ETn/MusD elements found within gene introns was confirmed using genomic PCR on DNA from a panel of mouse strains. For some cases, we detected gene-splicing abnormalities involving the ERV and obtained additional evidence for decreased gene expression in strains carrying the insertion. In total, we identified nearly 700 polymorphic IAP or ETn/MusD ERVs or solitary LTRs that reside in gene introns, providing potential candidates that may contribute to gene expression differences among strains. These extreme levels of polymorphism suggest that ERV insertions play a significant role in genetic drift of mouse lines. The laboratory mouse is the most widely used mammal for biological research. Hundreds of inbred mouse strains have been developed that vary in characteristics such as susceptibility to cancer or other diseases. There is much interest in uncovering differences between strains that result in different traits and, to aid this effort, millions of single nucleotide differences or polymorphisms between strains have been cataloged. To date, there has been less emphasis placed on other sources of genetic variation. In this study, we have conducted a genome-wide analysis to examine the level of polymorphism of mouse endogenous retroviral sequences (ERVs). ERVs are derived from infectious retroviruses that now exist in the genome and are inherited as part of chromosomes. Unlike in humans, genomic insertions of ERVs cause many new mutations in mice but their extent of variation between strains has been difficult to study because of their high copy numbers. By comparing genomic sequences of four common mouse strains, we found very high levels of polymorphism for two large active families of ERVs. Moreover, we documented nearly 700 polymorphic ERVs located within gene introns and found evidence that some of these affect gene transcript levels. This study demonstrates that ERV polymorphisms are a major source of genetic variability among mouse strains and likely contribute to strain-specific traits.
Collapse
|
8
|
Telomerase reverse transcriptase expression elevated by avian leukosis virus integration in B cell lymphomas. Proc Natl Acad Sci U S A 2007; 104:18952-7. [PMID: 18024587 DOI: 10.1073/pnas.0709173104] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Simple retroviruses induce tumors by integrating into the host genome, activating cellular oncogenes and microRNAs, or inactivating tumor suppressor genes. The identification of these genes elucidates molecular mechanisms of tumorigenesis. In this study, we identified avian leukosis virus (ALV) proviral integration sites in rapid-onset B cell lymphomas arising <12 weeks after infection of chicken embryos. By using inverse PCR, 28 unique viral integration sites were identified in rapid-onset tumors. Integrations in the telomerase reverse transcriptase (TERT) promoter/enhancer region were observed in four different tumors, suggesting that this is a common integration site. These provirus integrations ranged from 217 to 2,584 bp upstream of the TERT transcription initiation site and were all in the opposite transcriptional orientation to TERT. Southern blots of tumor samples demonstrated that these integrations are clonal and therefore occurred early in the process of tumorigenesis. Real-time RT-PCR showed overexpression of TERT mRNA in tumors harboring viral integrations in the TERT promoter. Telomerase activity was also up-regulated in these tumors; however, telomere-length alterations were not detected. Furthermore, viral LTR sequences directly enhanced the expression of luciferase reporters containing the TERT promoter sequences. This study documents retroviral up-regulation of cellular TERT by insertional activation to initiate or enhance tumor progression.
Collapse
|
9
|
Meijer D, van Agthoven T, Bosma PT, Nooter K, Dorssers LCJ. Functional screen for genes responsible for tamoxifen resistance in human breast cancer cells. Mol Cancer Res 2006; 4:379-86. [PMID: 16778085 DOI: 10.1158/1541-7786.mcr-05-0156] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Antiestrogens, such as tamoxifen, are widely used for endocrine treatment of estrogen receptor-positive breast cancer. However, as breast cancer progresses, development of tamoxifen resistance is inevitable. The mechanisms underlying this resistance are not well understood. To identify genes involved in tamoxifen resistance, we have developed a rapid screening method. To alter the tamoxifen-sensitive phenotype of human ZR-75-1 breast cancer cells into a tamoxifen-resistant phenotype, the cells were infected with retroviral cDNA libraries derived from human placenta, human brain, and mouse embryo. Subsequently, the cells were selected for proliferation in the presence of 4-hydroxy-tamoxifen (OH-TAM) and integrated cDNAs were identified by sequence similarity searches. From 155 OH-TAM-resistant cell colonies, a total of 25 candidate genes were isolated. Seven of these genes were identified in multiple cell colonies and thus cause antiestrogen resistance. The epidermal growth factor receptor, platelet-derived growth factor receptor-alpha, platelet-derived growth factor receptor-beta, colony-stimulating factor 1 receptor, neuregulin1, and fibroblast growth factor 17 that we have identified have been described as key regulators in the mitogen-activated protein kinase pathway. Therefore, this pathway could be a valuable target in the treatment of patients with breast cancer resistant to endocrine treatment. In addition, the putative gene LOC400500, predicted by in silico analysis, was identified. We showed that ectopic expression of this gene, designated as breast cancer antiestrogen resistance 4 (BCAR4), caused OH-TAM resistance and anchorage-independent cell growth in ZR-75-1 cells and that the intact open reading frame was required for its function. We conclude that retroviral transfer of cDNA libraries into human breast cancer cells is an efficient method for identifying genes involved in tamoxifen resistance.
Collapse
Affiliation(s)
- Danielle Meijer
- Department of Pathology, Josephine Nefkens Institute, Erasmus MC-University Medical Center, Rotterdam, the Netherlands
| | | | | | | | | |
Collapse
|
10
|
Crise B, Li Y, Yuan C, Morcock DR, Whitby D, Munroe DJ, Arthur LO, Wu X. Simian immunodeficiency virus integration preference is similar to that of human immunodeficiency virus type 1. J Virol 2005; 79:12199-204. [PMID: 16160146 PMCID: PMC1211548 DOI: 10.1128/jvi.79.19.12199-12204.2005] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2005] [Accepted: 07/05/2005] [Indexed: 01/19/2023] Open
Abstract
Simian immunodeficiency virus (SIV) is a useful model for studying human immunodeficiency virus (HIV) pathogenesis and vaccine efficacy. As with all other retroviruses, integration is a necessary step in the replication cycle of SIV. The location of the retrovirus integration site is known to impact on viral gene expression, establishment of viral latency, and other aspects of the replication cycle of a retrovirus. In this study, 148 SIV provirus integration sites were sequenced and mapped in the human genome. Our analysis showed that SIV integration, like that of HIV type 1 (HIV-1), exhibited a strong preference for actively transcribed regions in the genome (A. R. Schroder et al., Cell 110:521-529, 2002) and no preference for the CpG islands or transcription start sites, in contrast to observations for murine leukemia virus (X. Wu et al., Science 300:1749-1751, 2003). The parallel integration target site preferences of SIV and HIV-1 suggest that these lentiviruses may share similar mechanisms for target site selection and that SIV serves as an accurate model of HIV-1 with respect to integration.
Collapse
Affiliation(s)
- Bruce Crise
- AIDS Vaccine Program, Scientific Application International Corporation-Frederick, National Cancer Institute at Frederick, Frederick, MD 21701, USA
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Nagashima N, Hisasue M, Nishigaki K, Miyazawa T, Kano R, Hasegawa A. In vitro selective suppression of feline myeloid colony formation is attributable to molecularly cloned strain of feline leukemia virus with unique long terminal repeat. Res Vet Sci 2005; 78:151-4. [PMID: 15563922 DOI: 10.1016/j.rvsc.2004.07.003] [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: 06/28/2004] [Indexed: 11/28/2022]
Abstract
Molecularly cloned feline leukemia virus (FeLV)-clone 33 (C-33), derived from a cat with acute myelocytic leukemia (AML), was examined to assess its relation to the pathogenesis of AML and myelodysplastic syndrome (MDS). To evaluate in vitro pathogenicity of FeLV C-33, bone marrow colony-forming assay was performed on marrow cells infected with FeLV C-33 or an FeLV subgroup A strain (61E, a molecularly cloned strain with minimal pathogenicity). The myeloid colony-forming activity of feline bone marrow mononuclear cells infected with FeLV C-33 was significantly lower than that of cells infected with 61E. This suggests that FeLV C-33 has myeloid lineage-specific pathogenicity for cats, and that FeLV C-33 infection is useful as an experimental model for investigating pathogenesis of MDS and AML.
Collapse
MESH Headings
- Animals
- Bone Marrow Cells/cytology
- Bone Marrow Cells/virology
- Cat Diseases/virology
- Cats
- Cloning, Molecular
- DNA, Viral/chemistry
- DNA, Viral/genetics
- Leukemia Virus, Feline/genetics
- Leukemia Virus, Feline/pathogenicity
- Leukemia, Myeloid, Acute/pathology
- Leukemia, Myeloid, Acute/veterinary
- Leukemia, Myeloid, Acute/virology
- Myelodysplastic Syndromes/veterinary
- Myelodysplastic Syndromes/virology
- Myeloid Progenitor Cells/cytology
- Myeloid Progenitor Cells/virology
- Polymerase Chain Reaction/veterinary
- Retroviridae Infections/veterinary
- Retroviridae Infections/virology
- Terminal Repeat Sequences
- Tumor Virus Infections/veterinary
- Tumor Virus Infections/virology
Collapse
Affiliation(s)
- N Nagashima
- Department of Pathobiology, Nihon University School of Veterinary Medicine, 1866, Kameino, Fujisawa, Kanagawa 252-8510, Japan
| | | | | | | | | | | |
Collapse
|
12
|
Abstract
The retroviral capacity for integration into the host genome can give rise to endogenous retroviruses (ERVs): retroviral sequences that are transmitted vertically as part of the host germ line, within which they may continue to replicate and evolve. ERVs represent both a unique archive of ancient viral sequence information and a dynamic component of host genomes. As such they hold great potential as informative markers for studies of both virus evolution and host genome evolution. Numerous novel ERVs have been described in recent years, particularly as genome sequencing projects have advanced. This review discusses the evolution of ERV lineages, considering the processes by which ERV distribution and diversity is generated. The diversity of ERVs isolated so far is summarised in terms of both their distribution across host taxa, and their relationships to recognised retroviral genera. Finally the relevance of ERVs to studies of genome evolution, host disease and viral ecology is considered, and recent findings discussed.
Collapse
Affiliation(s)
- Robert Gifford
- Department of Biological Sciences, Imperial College, Silwood Park, Buckhurst Road, Ascot Berkshire, SL5 7PY, UK
| | | |
Collapse
|
13
|
Salman A, Ramesh J, Erukhimovitch V, Talyshinsky M, Mordechai S, Huleihel M. FTIR microspectroscopy of malignant fibroblasts transformed by mouse sarcoma virus. JOURNAL OF BIOCHEMICAL AND BIOPHYSICAL METHODS 2003; 55:141-53. [PMID: 12628697 DOI: 10.1016/s0165-022x(02)00182-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Fourier transform infrared microspectroscopy (FTIR-MSP), which is based on the characteristic molecular vibrational spectra of cells, was used to investigate spectral differences between normal primary rabbit bone marrow (BM) cells and bone marrow cells transformed (BMT) by murine sarcoma virus (MuSV). Primary cells, rather than cell lines, were used for this research because primary cells are similar to normal tissue cells in most of their characteristics. Our results showed dramatic changes in absorbance between the control cells and MuSV124-transformed cells. Various biological markers, such as the phosphate level and the RNA/DNA obtained, based on the analysis of the FTIR-MSP spectra, also displayed significant differences between the control and transformed cells. Preliminary results suggested that the cluster analysis performed on the FTIR-MSP spectra yielded 100% accuracy in classifying both types of cells.
Collapse
MESH Headings
- Amides/analysis
- Amides/chemistry
- Amides/metabolism
- Animals
- Biomarkers, Tumor/analysis
- Biomarkers, Tumor/chemistry
- Biomarkers, Tumor/metabolism
- Bone Marrow Cells/chemistry
- Bone Marrow Cells/classification
- Bone Marrow Cells/metabolism
- Bone Marrow Cells/virology
- Cell Transformation, Viral
- Cluster Analysis
- DNA, Neoplasm/analysis
- DNA, Neoplasm/chemistry
- DNA, Neoplasm/metabolism
- Fibroblasts/chemistry
- Fibroblasts/classification
- Fibroblasts/metabolism
- Fibroblasts/pathology
- Fibroblasts/virology
- Mice
- Microspectrophotometry/methods
- Phosphates/analysis
- Phosphates/chemistry
- Phosphates/metabolism
- RNA, Neoplasm/analysis
- RNA, Neoplasm/chemistry
- RNA, Neoplasm/metabolism
- Rabbits
- Reference Values
- Sarcoma Viruses, Murine
- Spectroscopy, Fourier Transform Infrared/methods
- Tumor Cells, Cultured
Collapse
Affiliation(s)
- Ahmad Salman
- Department of Physics, Ben Gurion University of the Negev, 84105, Beer-Sheva, Israel
| | | | | | | | | | | |
Collapse
|
14
|
Hanlon L, Barr NI, Blyth K, Stewart M, Haviernik P, Wolff L, Weston K, Cameron ER, Neil JC. Long-range effects of retroviral insertion on c-myb: overexpression may be obscured by silencing during tumor growth in vitro. J Virol 2003; 77:1059-68. [PMID: 12502821 PMCID: PMC140821 DOI: 10.1128/jvi.77.2.1059-1068.2003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2002] [Accepted: 10/09/2002] [Indexed: 11/20/2022] Open
Abstract
The c-myb oncogene is a frequent target for retroviral activation in hemopoietic tumors of avian and mammalian species. While insertions can target the gene directly, numerous clusters of retroviral insertion sites have been identified which map close to c-myb and outside the transcription unit in T-lymphomas (Ahi-1, fit-1, and Mis-2) and monocytic and myeloid leukemias (Mml1, Mml2, Mml3, and Epi-1). Previous analyses showed no consistent effect of these insertions on c-myb expression, raising the possibility that other nearby genes were the true targets. In contrast, our analysis of four cell lines established from lymphomas bearing insertions at fit-1 (fti-1) (feline leukemia virus) and Ahi-1 (Moloney murine leukemia virus) shows that these display higher expression levels of c-myb RNA and protein compared to a panel of phenotypically similar cell lines lacking such insertions. An interesting feature of the cell lines with long-range c-myb insertions was that each also carried an activated Myc allele. The potential for oncogenic synergy between Myb and Myc in T-cell lymphoma was confirmed in transgenic mice overexpressing alleles of both genes in the T-cell compartment, lending further credence to the case for c-myb as the major target for long-range activation. In contrast, mapping and analysis of c-myb neighboring genes (HBS1 and FLJ20069) showed that the expression of these genes did not correlate well with the presence of proviral insertions. A possible explanation for the paradoxical behavior of c-myb was provided by one of the murine T-lymphoma lines bearing an insertion at Ahi-1 (p/m16i) that reproducibly down-regulated c-myb RNA and protein to very low levels or undetectable levels on prolonged culture. Our observations implicate c-myb as a key target of upstream and downstream retroviral insertions. However, overexpression may become dispensable during outgrowth in vitro, and perhaps during tumor progression in vivo, providing a potential rationale for the previously observed discordance between retroviral insertion and c-myb expression levels.
Collapse
Affiliation(s)
- L Hanlon
- Molecular Oncology Laboratory, Department of Veterinary Pathology, University of Glasgow, Bearsden, United Kingdom.
| | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Jiang X, Hanna Z, Kaouass M, Girard L, Jolicoeur P. Ahi-1, a novel gene encoding a modular protein with WD40-repeat and SH3 domains, is targeted by the Ahi-1 and Mis-2 provirus integrations. J Virol 2002; 76:9046-59. [PMID: 12186888 PMCID: PMC136442 DOI: 10.1128/jvi.76.18.9046-9059.2002] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Ahi-1 locus was initially identified as a common helper provirus integration site in Abelson pre-B-cell lymphomas and shown to be closely linked to the c-myb proto-oncogene. Since no significant alteration of c-myb expression was found in Abelson murine leukemia virus-induced pre-B-lymphomas harboring a provirus inserted within the Ahi-1 locus, this suggested that it harbors another gene whose dysregulation is involved in tumor formation. Here we report the identification of a novel gene (Ahi-1) targeted by these provirus insertional mutations and the cloning of its cDNA. The Ahi-1 proviral insertions were found at the 3' end of the gene, in an inverse transcriptional orientation, with most of them located around and downstream of the last exon, whereas another insertion was within intron 22. In addition, another previously identified provirus insertion site, Mis-2, was found to map within the 16th intron of the Ahi-1 gene. The Ahi-1 cDNA encodes a 1,047-amino-acid protein. The predicted Ahi-1 protein is a modular protein that contains one SH3 motif and seven WD40 repeats. The Ahi-1 gene is conserved in mammals and encodes two major RNA species of 5 and 4.2 kb and several other shorter splicing variants. The Ahi-1 gene is expressed in mouse embryos and in several organs of the mouse and rat, notably at high levels in the brain and testes. In tumor cells harboring insertional mutations in Ahi-1, truncated Ahi-1/viral fused transcripts were identified, including some splicing variants with deletion of the SH3 domain. Therefore, Ahi-1 is a novel gene targeted by provirus insertion and encoding a protein that exhibits several features of a signaling molecule. Thus, Ahi-1 may play an important role in signal transduction in normal cells and may be involved in tumor development, possibly in cooperation with other oncogenes (such as v-abl and c-myc) or with a tumor suppressor gene (Nf1), since Ahi-1 insertion sites were identified in tumors harboring v-abl defective retroviruses or a c-myc transgene or in tumors exhibiting deletion of Nf1.
Collapse
Affiliation(s)
- Xiaoyan Jiang
- Laboratory of Molecular Biology, Clinical Research Institute of Montreal, Montreal, H2W 1R7 Quebéc, Canada
| | | | | | | | | |
Collapse
|
16
|
Stewart M, MacKay N, Cameron ER, Neil JC. The common retroviral insertion locus Dsi1 maps 30 kilobases upstream of the P1 promoter of the murine Runx3/Cbfa3/Aml2 gene. J Virol 2002; 76:4364-9. [PMID: 11932403 PMCID: PMC155108 DOI: 10.1128/jvi.76.9.4364-4369.2002] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Dsi1 locus was identified as a common integration site for Moloney murine leukemia virus (MLV) in rat thymic lymphomas, but previous efforts to identify a gene affected by these insertions were unsuccessful. We considered the Runx3 gene a potential candidate on the basis of genetic mapping which showed that Dsi1 and Runx3 are closely linked on mouse chromosome 4 and the precedent of the related Runx2 gene, which emerged recently as a Myc-collaborating gene activated by retroviral insertion in thymic lymphomas of CD2-MYC mice. We now report the physical mapping of the Dsi1 locus to a site 30 kb upstream of the distal (P1) promoter of the murine Runx3 gene. Comparison with the syntenic region of human chromosome 1 shows that the next gene is over 250 kb 5' to Runx3, suggesting that Runx3 may be the primary target of retroviral insertions at Dsi1. Screening of CD2-MYC lymphomas for rearrangements at Dsi1 revealed a tumor cell line harboring an MLV provirus at this locus, in the orientation opposite that of Runx3. Proviral insertion was associated with very high levels of expression of Runx3, with a preponderance of transcripts arising at the P1 promoter. These results confirm that Runx3 is a target of retroviral insertions at Dsi1 and indicate that Runx3 can act as an alternative to Runx2 as a Myc-collaborating gene in thymic lymphoma.
Collapse
Affiliation(s)
- Monica Stewart
- Molecular Oncology Laboratory, Institute of Comparative Medicine, University of Glasgow Veterinary School, Glasgow G61 1QH, United Kingdom.
| | | | | | | |
Collapse
|
17
|
Berg T, Cohen SB, Desharnais J, Sonderegger C, Maslyar DJ, Goldberg J, Boger DL, Vogt PK. Small-molecule antagonists of Myc/Max dimerization inhibit Myc-induced transformation of chicken embryo fibroblasts. Proc Natl Acad Sci U S A 2002; 99:3830-5. [PMID: 11891322 PMCID: PMC122609 DOI: 10.1073/pnas.062036999] [Citation(s) in RCA: 241] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Myc is a transcriptional regulator of the basic helix-loop-helix leucine zipper protein family. It has strong oncogenic potential, mutated or virally transduced forms of Myc induce lymphoid tumors in animals, and deregulated expression of Myc is associated with numerous types of human cancers. For its oncogenic activity, Myc must dimerize with the ubiquitously expressed basic helix-loop-helix leucine zipper protein Max. This requirement for dimerization may allow control of Myc activity with small molecules that interfere with Myc/Max dimerization. We have measured Myc/Max dimerization with fluorescence resonance energy transfer and have screened combinatorial chemical libraries for inhibitors of dimerization. Candidate inhibitors were isolated from a peptidomimetics library. Inhibition of Myc/Max interaction was validated by ELISA and electrophoretic mobility-shift assay. Two of the candidate inhibitors also interfere with Myc-induced oncogenic transformation in chicken embryo fibroblast cultures. Our work provides proof of principle for the identification of small molecule inhibitors of protein-protein interactions by using high-throughput screens of combinatorial chemical libraries.
Collapse
Affiliation(s)
- Thorsten Berg
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Broussard DR, Mertz JA, Lozano M, Dudley JP. Selection for c-myc integration sites in polyclonal T-cell lymphomas. J Virol 2002; 76:2087-99. [PMID: 11836386 PMCID: PMC153816 DOI: 10.1128/jvi.76.5.2087-2099.2002] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Type B leukemogenic virus (TBLV) is highly related to mouse mammary tumor virus but induces rapidly appearing T-cell lymphomas in mice. Unlike other T-cell tumors induced by retroviruses, only 5 to 10% of TBLV-induced lymphomas have detectable viral integrations near c-myc by Southern blotting, whereas Northern blotting has shown that most tumors have two- to sixfold overexpression of c-myc RNA. In this report, PCR was used to demonstrate that at least 30% of these lymphomas have TBLV insertions near c-myc. Some tumors contained multiple TBLV proviruses in different locations and orientations, suggesting that the tumors are polyclonal. The integrated proviruses near c-myc had different numbers (two to four) of long terminal repeat (LTR) enhancer repeats, although LTRs with three-repeat enhancers dominated the proviral population. Passage of polyclonal tumors in immunocompetent mice and semiquantitative PCR revealed that only cells with particular integrations were selected for growth. In three of six tumors tested, proviruses containing four-repeat enhancers near c-myc were selected during tumor passage. Since tumor cell selection may be accomplished by overexpression of c-myc RNA due to proximity to the unique TBLV LTR enhancer, we inserted LTRs at various locations within a plasmid containing the entire c-myc locus and cellular flanking sequences. To quantitatively measure effects on transcription, the Renilla luciferase gene was substituted for most of c-myc exon 2, and transient transfections were performed with c-myc reporter constructs in two different T-cell lines. As expected, insertion of a TBLV LTR with three-repeat enhancers in either orientation, 5" and 3", of the myc gene elevated reporter activity from 2- to 160-fold, consistent with enhancer function, but four-repeat LTRs had lower levels of expression compared to three-repeat LTRs. Surprisingly, LTR insertions that gave maximal c-myc expression in transient-transfection assays declined in tumor cells selected for growth in vivo. Selection for clonal growth may occur in tumor cells that have modest c-myc overexpression after proviral insertion to prevent apoptosis.
Collapse
Affiliation(s)
- Dana R Broussard
- Section of Molecular Genetics and Microbiology, Institute for Cellular and Molecular Biology, The University of Texas at Austin, 100 W. 24th Street, Austin, TX 78712, USA
| | | | | | | |
Collapse
|
19
|
Nishigaki K, Hanson C, Thompson D, Yugawa T, Hisasue M, Tsujimoto H, Ruscetti S. Analysis of the disease potential of a recombinant retrovirus containing Friend murine leukemia virus sequences and a unique long terminal repeat from feline leukemia virus. J Virol 2002; 76:1527-32. [PMID: 11773427 PMCID: PMC135779 DOI: 10.1128/jvi.76.3.1527-1532.2002] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
We have molecularly cloned a feline leukemia virus (FeLV) (clone 33) from a domestic cat with acute myeloid leukemia (AML). The long terminal repeat (LTR) of this virus, like the LTRs present in FeLV proviruses from other cats with AML, contains an unusual structure in its U3 region upstream of the enhancer (URE) consisting of three tandem direct repeats of 47 bp. To test the disease potential and specificity of this unique FeLV LTR, we replaced the U3 region of the LTR of the erythroleukemia-inducing Friend murine leukemia virus (F-MuLV) with that of FeLV clone 33. When the resulting virus, F33V, was injected into newborn mice, almost all of the mice eventually developed hematopoietic malignancies, with a significant percentage being in the myeloid lineage. This is in contrast to mice injected with an F-MuLV recombinant containing the U3 region of another FeLV that lacks repetitive URE sequences, none of which developed myeloid malignancies. Examination of tumor proviruses from F33V-infected mice failed to detect any changes in FeLV U3 sequences other than that in the URE. Like F-MuLV-infected mice, those infected with the F-MuLV/FeLV recombinants were able to generate and replicate mink cell focus-inducing viruses. Our studies are consistent with the idea that the presence of repetitive sequences upstream of the enhancer in the LTR of FeLV may favor the activation of this promoter in myeloid cells and contribute to the development of malignancies in this hematopoietic lineage.
Collapse
MESH Headings
- Animals
- Base Sequence
- Cats
- Cell Line
- Cloning, Molecular
- DNA, Viral
- Friend murine leukemia virus/genetics
- Friend murine leukemia virus/physiology
- Leukemia Virus, Feline/genetics
- Leukemia, Erythroblastic, Acute/virology
- Leukemia, Experimental/virology
- Leukemia, Myeloid/virology
- Lymphoma/virology
- Mice
- Mink Cell Focus-Inducing Viruses/genetics
- Molecular Sequence Data
- Recombination, Genetic
- Retroviridae
- Retroviridae Infections/virology
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
- Terminal Repeat Sequences
- Tumor Virus Infections/virology
Collapse
Affiliation(s)
- Kazuo Nishigaki
- Basic Research Laboratory, National Cancer Institute, Frederick, Maryland 21702-1201, USA
| | | | | | | | | | | | | |
Collapse
|
20
|
Huleihel M, Salman A, Erukhimovitch V, Ramesh J, Hammody Z, Mordechai S. Novel spectral method for the study of viral carcinogenesis in vitro. JOURNAL OF BIOCHEMICAL AND BIOPHYSICAL METHODS 2002; 50:111-21. [PMID: 11741700 DOI: 10.1016/s0165-022x(01)00177-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Fourier transform infrared (FTIR) spectroscopy is a unique technique for the laboratory diagnosis of cellular variations based on the characteristic molecular vibrational spectra of the cells. Microscopic FTIR was used to investigate spectral differences between normal and malignant fibroblasts transformed by retrovirus infection. A detailed analysis showed significant differences between cancerous and normal cells. The contents of vital cellular metabolites were significantly lower in the transformed cells than in the normal cells. In an attempt to identify the cellular components responsible for the observed spectral differences between normal and cancerous cells, we found significant differences between DNA of normal and cancerous cells.
Collapse
Affiliation(s)
- Mahmoud Huleihel
- The Institute for Applied Biosciences, Ben-Gurion University of the Negev, P.O. Box 653, Beersheba 84105, Israel.
| | | | | | | | | | | |
Collapse
|
21
|
Martín-Hernández J, Sørensen AB, Pedersen FS. Murine leukemia virus proviral insertions between the N-ras and unr genes in B-cell lymphoma DNA affect the expression of N-ras only. J Virol 2001; 75:11907-12. [PMID: 11689675 PMCID: PMC114780 DOI: 10.1128/jvi.75.23.11907-11912.2001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Akv1-99, a variant of Akv murine leukemia virus, induces B-cell lymphomas with nearly 100% incidence and a mean latency period of 12 months after injection into newborn NMRI mice. PCR amplification and sequence analyses of DNA flanking integrated proviruses revealed proviral insertion into the N-ras/unr (upstream of N-ras) locus in 2 out of 13 B-cell lymphomas, both of which appeared clonal by Southern blotting analysis. These two tumors showed increased expression levels of N-ras by Northern blotting, as did a third tumor shown by reverse transcriptase PCR to have a nonclonal provirus integration located in the same area. However, no significant changes in expression were observed when using a specific probe for the unr gene. All proviruses were integrated in the same transcriptional orientation as unr and N-ras genes. By promoter insertion, the two Akv1-99 proviruses integrated between exon -1 and exon 1 of N-ras gave rise to two different spliced products, whereas the provirus integrated into unr used only an exon skipping pattern. The absence of mutations of the N-ras codons 12, 13, 18, and 61 suggests that activation of the proto-oncogene is exclusively due to overexpression by retroviral promoter insertion, and furthermore, Northern blot analyses indicate that the expression of unr is unaffected by N-ras overexpression even in the case where the unr gene itself is the target of proviral insertion. Thus, altogether our findings indicate that overexpression of N-ras plays a role in development of murine leukemia virus-induced B-cell lymphomas, leaving the expression of the tightly linked unr gene unaltered.
Collapse
Affiliation(s)
- J Martín-Hernández
- Department of Molecular and Structural Biology, University of Aarhus, DK-8000 Aarhus C, Denmark
| | | | | |
Collapse
|
22
|
Palmarini M, Fan H. Retrovirus-induced ovine pulmonary adenocarcinoma, an animal model for lung cancer. J Natl Cancer Inst 2001; 93:1603-14. [PMID: 11698564 DOI: 10.1093/jnci/93.21.1603] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Studies on the molecular mechanisms of transformation of retrovirus-induced neoplasms in domestic and laboratory animal species have provided insights into the genetic basis of cancer. Ovine pulmonary adenocarcinoma (OPA) is a retrovirus-induced spontaneous lung tumor of sheep that has striking analogies to some forms of human adenocarcinoma. The etiologic agent of OPA, jaagsiekte sheep retrovirus (JSRV), is unique among retroviruses for having a specific tropism for the differentiated epithelial cells of the lung, and it is the only virus known to cause a naturally occurring lung adenocarcinoma. Expression of the JSRV envelope protein is sufficient to induce cell transformation in vitro, possibly via the activation of the phosphatidylinositol 3-kinase/Akt-signaling pathway mediated by the cytoplasmic tail of the transmembrane protein. The aim of this review is to draw the attention of basic and clinical scientists engaged in lung cancer research to this unique animal model, to explore the possible use of OPA as a tool to investigate the mechanisms of pulmonary carcinogenesis, and to underline the similarities between OPA and some forms of human lung adenocarcinoma. The possibility of a viral etiology for the latter will be evaluated in this review.
Collapse
Affiliation(s)
- M Palmarini
- Department of Medical Microbiology and Parasitology, College of Veterinary Medicine, University of Georgia, Athens, 30602, USA.
| | | |
Collapse
|
23
|
Liu D, Yang X, Yang D, Songyang Z. Genetic screens in mammalian cells by enhanced retroviral mutagens. Oncogene 2000; 19:5964-72. [PMID: 11146547 DOI: 10.1038/sj.onc.1203992] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Genetic approaches such as retrovirus-mediated mutagenesis and cDNA expression libraries have contributed greatly to our understanding of signal transduction in mammalian cells. However, previously described methods for retroviral insertional mutagenesis are hindered by low mutagenesis rates and difficulties in cloning mutated genes. cDNA expression library methods are usually cell-type dependent and bias towards abundant and short messages. With the near completion of the genome projects, alternative genetic methods are needed where large numbers of genes can be more easily isolated and biochemically studied. We have developed a novel retrovirus-mediated genetic screening method in cultured cells. To achieve efficient and regulated mutagenesis, we constructed Enhanced Retroviral Mutagen (ERM) vectors that contained several engineered sequences (e.g., an ERM Tag and a splice donor) controlled by a tetracycline-responsive promoter. Endogenous genes can thus be randomly activated and tagged in a conditional system. NIH3T3 cells were used to screen for focus-forming genes using the ERM strategy. We showed that these added sequences increased the screening efficiency by >10-fold, and allowed more direct identification of the genes targeted. Sequence analysis of approximately 10% of the >600 focus clones recovered revealed both known oncogenes and novel factors such as protein kinases and GTP/GDP exchange proteins. The ERM strategy should help to facilitate large-scale gene identification in diverse pathways and integrate both genetic (with the completion of the genome projects) and functional information more readily.
Collapse
Affiliation(s)
- D Liu
- Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
| | | | | | | |
Collapse
|
24
|
Leclercq I, Mortreux F, Cavrois M, Leroy A, Gessain A, Wain-Hobson S, Wattel E. Host sequences flanking the human T-cell leukemia virus type 1 provirus in vivo. J Virol 2000; 74:2305-12. [PMID: 10666261 PMCID: PMC111712 DOI: 10.1128/jvi.74.5.2305-2312.2000] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Human pathogenic retroviruses do not have common loci of integration. However, many factors, such as chromatin structure, transcriptional activity, DNA-protein interaction, CpG methylation, and nucleotide composition of the target sequence, may influence integration site selection. These features have been investigated by in vitro integration reactions or by infection of cell lines with recombinant retroviruses. Less is known about target choice for integration in vivo. The present study was conducted in order to assess the characteristics of cellular sequences targeted for human T-cell leukemia virus type 1 (HTLV-1) integration in vivo. Sequencing integration sites from >/=200 proviruses (19 kb of sequence) isolated from 29 infected individuals revealed that HTLV-1 integration is not random at the level of the nucleotide sequence. The virus was found to integrate in A/T-rich regions with a weak consensus sequence at positions within and without of the hexameric repeat generated during integration. These features were not associated with a preference for integration near active regions or repeat elements of the host chromosomes. Most or all of the regions of the genome appear to be accessible to HTLV-1 integration. As with integration in vitro, integration specificity in vivo seems to be determined by local features rather than by the accessibility of specific regions.
Collapse
Affiliation(s)
- I Leclercq
- Unité 524 INSERM, Institut de Recherche sur le Cancer de Lille, France
| | | | | | | | | | | | | |
Collapse
|
25
|
Butel JS. Viral carcinogenesis: revelation of molecular mechanisms and etiology of human disease. Carcinogenesis 2000; 21:405-26. [PMID: 10688861 DOI: 10.1093/carcin/21.3.405] [Citation(s) in RCA: 213] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The RNA and DNA tumor viruses have made fundamental contributions to two major areas of cancer research. Viruses were vital, first, to the discovery and analysis of cellular growth control pathways and the synthesis of current concepts of cancer biology and, second, to the recognition of the etiology of some human cancers. Transforming retroviruses carry oncogenes derived from cellular genes that are involved in mitogenic signalling and growth control. DNA tumor viruses encode oncogenes of viral origin that are essential for viral replication and cell transformation; viral oncoproteins complex with cellular proteins to stimulate cell cycle progression and led to the discovery of tumor suppressors. Viral systems support the concept that cancer development occurs by the accumulation of multiple cooperating events. Viruses are now accepted as bona fide etiologic factors of human cancer; these include hepatitis B virus, Epstein-Barr virus, human papillomaviruses, human T-cell leukemia virus type I and hepatitis C virus, plus several candidate human cancer viruses. It is estimated that 15% of all human tumors worldwide are caused by viruses. The infectious nature of viruses distinguishes them from all other cancer-causing factors; tumor viruses establish long-term persistent infections in humans, with cancer an accidental side effect of viral replication strategies. Viruses are usually not complete carcinogens, and the known human cancer viruses display different roles in transformation. Many years may pass between initial infection and tumor appearance and most infected individuals do not develop cancer, although immunocompromised individuals are at elevated risk of viral-associated cancers. Variable factors that influence viral carcinogenesis are reviewed, including possible synergy between viruses and environmental cofactors. The difficulties in establishing an etiologic role for a virus in human cancer are discussed, as well as the different approaches that proved viral links to cancer. Future directions for tumor virus studies are considered.
Collapse
Affiliation(s)
- J S Butel
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Mail Stop BCM-385, One Baylor Plaza, Houston, TX 77030, USA.
| |
Collapse
|
26
|
Chu W, Pak BJ, Bani MR, Kapoor M, Lu SJ, Tamir A, Kerbel RS, Ben-David Y. Tyrosinase-related protein 2 as a mediator of melanoma specific resistance to cis-diamminedichloroplatinum(II): therapeutic implications. Oncogene 2000; 19:395-402. [PMID: 10656687 DOI: 10.1038/sj.onc.1203315] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A major obstacle in the systemic treatment of advanced malignant melanoma is its intrinsic resistance to conventionally used chemotherapeutic agents. In order to investigate the mechanisms of this intrinsic resistance, we have previously utilized retroviral insertional mutagenesis on an early-stage, drug sensitive human melanoma cell line (WM35) to establish mutated cell lines that exhibited increased resistance to cis-diammi-nedichloroplatinum(II) (CDDP). Here, we demonstrate that this increased resistance to CDDP is mediated by the over-expression of tyrosinase-related protein-2 (TYRP2), an enzyme that normally functions in the biosynthesis of the pigment, melanin. Northern and Western blot analyses revealed that the expression of TYRP2 in the virally-derived cell lines as well as in a panel of human melanoma cell lines positively correlated with their levels of resistance to CDDP. Furthermore, enforced expression of TYRP2 in WM35 cells by transfection elevated their resistance to CDDP. The increased CDDP resistance in the virally-derived clones and TYRP2 transfectants was accompanied by a reduction in CDDP-induced apoptosis. Interestingly, the virally-derived CDDP-resistant clones also showed cross resistance to carboplatin and methotrexate, but not taxol, suggesting that TYRP2 over-expression may confer resistance specifically to DNA damaging agents. Overall, these results demonstrate a novel mechanism of drug resistance in human melanoma cells that is mediated by the over-expression of TYRP2. Since TYRP2 is expressed only in cells of melanocytic lineage, this may represent the first report of a lineage-specific mechanism of drug resistance. In summary, these findings suggest a significant role for TYRP2 in the intrinsic drug resistance phenotype of human melanoma cells and may have important implications in the development of chemosensitization strategies for the clinical management of this disease.
Collapse
Affiliation(s)
- W Chu
- Sunnybrook and Women's College Health Sciences Centre, Division of Cancer Biology Research, Toronto, Ontario, Canada
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Audit M, Déjardin J, Hohl B, Sidobre C, Hope TJ, Mougel M, Sitbon M. Introduction of a cis-acting mutation in the capsid-coding gene of moloney murine leukemia virus extends its leukemogenic properties. J Virol 1999; 73:10472-9. [PMID: 10559365 PMCID: PMC113102 DOI: 10.1128/jvi.73.12.10472-10479.1999] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Inoculation of newborn mice with the retrovirus Moloney murine leukemia virus (MuLV) results in the exclusive development of T lymphomas with gross thymic enlargement. The T-cell leukemogenic property of Moloney MuLV has been mapped to the U3 enhancer region of the viral promoter. However, we now describe a mutant Moloney MuLV which can induce the rapid development of a uniquely broad panel of leukemic cell types. This mutant Moloney MuLV with synonymous differences (MSD1) was obtained by introduction of nucleotide substitutions at positions 1598, 1599, and 1601 in the capsid gene which maintained the wild-type (WT) coding potential. Leukemias were observed in all MSD1-inoculated animals after a latency period that was shorter than or similar to that of WT Moloney MuLV. Importantly, though, only 56% of MSD1-induced leukemias demonstrated the characteristic thymoma phenotype observed in all WT Moloney MuLV leukemias. The remainder of MSD1-inoculated animals presented either with bona fide clonal erythroid or myelomonocytic leukemias or, alternatively, with other severe erythroid and unidentified disorders. Amplification and sequencing of U3 and capsid-coding regions showed that the inoculated parental MSD1 sequences were conserved in the leukemic spleens. This is the first report of a replication-competent MuLV lacking oncogenes which can rapidly lead to the development of such a broad range of leukemic cell types. Moreover, the ability of MSD1 to transform erythroid and myelomonocytic lineages is not due to changes in the U3 viral enhancer region but rather is the result of a cis-acting effect of the capsid-coding gag sequence.
Collapse
MESH Headings
- 3T3 Cells
- Animals
- Capsid/genetics
- Capsid/physiology
- Cell Line
- Cell Transformation, Neoplastic
- Cell Transformation, Viral
- Friend murine leukemia virus/genetics
- Friend murine leukemia virus/physiology
- Gene Products, gag/genetics
- Gene Products, gag/physiology
- Genes, Viral
- Leukemia, Erythroblastic, Acute/classification
- Leukemia, Erythroblastic, Acute/pathology
- Leukemia, Erythroblastic, Acute/virology
- Leukemia, Myelomonocytic, Acute/classification
- Leukemia, Myelomonocytic, Acute/pathology
- Leukemia, Myelomonocytic, Acute/virology
- Mice
- Moloney murine leukemia virus/genetics
- Moloney murine leukemia virus/physiology
- Mutagenesis
- Retroviridae Infections/pathology
- Retroviridae Infections/virology
- Terminal Repeat Sequences
- Tumor Virus Infections/pathology
- Tumor Virus Infections/virology
Collapse
Affiliation(s)
- M Audit
- Institut de Génétique Moléculaire de Montpellier (IGMM), IFR24, CNRS-UMR5535, and Université Montpellier II, F-34293 Montpellier Cedex 5, France
| | | | | | | | | | | | | |
Collapse
|
28
|
Abstract
The v-Myb oncogene causes late onset T cell lymphomas when expressed in the T cell lineage of transgenic mice. In order to define the cellular mutations cooperating with s-Myb to cause lymphomas, we have infected v-Myb transgenic mice with Moloney murine leukemia virus (M-MuLV). Tumor formation is significantly accelerated from a mean age of onset of 60 weeks in uninfected vMyb transgenics to 13 weeks in infected vMyb transgenics. We studied the loci into which the M-MuLV had inserted, and found that in 73% of animals, either the c-myc or the N-myc genes had been disrupted and deregulated. Therefore, v-myb and c-myb can cooperate to induce T cell lymphomas.
Collapse
MESH Headings
- Age of Onset
- Animals
- Flow Cytometry
- Gene Expression
- Genes, myc/genetics
- Leukemia Virus, Murine/physiology
- Lymphoma, T-Cell/genetics
- Lymphoma, T-Cell/pathology
- Lymphoma, T-Cell/virology
- Mice
- Mice, Inbred CBA
- Mice, Transgenic
- Mutagenesis, Insertional
- Oncogene Proteins v-myb
- Oncogenes/genetics
- Polymerase Chain Reaction
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Retroviridae Proteins, Oncogenic/genetics
- T-Lymphocytes/metabolism
- T-Lymphocytes/pathology
- T-Lymphocytes/virology
- Thymoma/genetics
- Thymoma/pathology
- Thymoma/virology
- Thymus Neoplasms/genetics
- Thymus Neoplasms/pathology
- Thymus Neoplasms/virology
Collapse
Affiliation(s)
- J Davies
- CRC Centre for Cell and Molecular Biology, Institute of Cancer Research, London, UK
| | | | | |
Collapse
|
29
|
Abstract
Hematopoietic tumors in both humans and mice frequently up-regulate expression of the c-myb gene, but it is unclear whether this is a cause or a consequence of the leukemic state. Recent results placing super-activation of the c-Myb protein at the bottom of a kinase-activated signal transduction pathway indicate that it may be a downstream effector of transformation induced by other oncogenes. The relationship between c-Myb and the serine-threonine kinase pim-1, its immediate activator, is discussed, together with the possibility that c-Myb, like pim-1, may be able to synergize with c-Myc to induce tumors.
Collapse
Affiliation(s)
- K Weston
- CRC Centre for Cell and Molecular Biology, Institute of Cancer Research, London, UK
| |
Collapse
|
30
|
Fehse B, Kühlcke K, Langer A, Ostertag W, Lother H. Rapid and efficient cloning of proviral flanking fragments by kanamycin resistance gene complementation. Nucleic Acids Res 1999; 27:706-7. [PMID: 9863001 PMCID: PMC148236 DOI: 10.1093/nar/27.2.706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have developed a technique for the rapid cloning of unknown flanking regions of transgenic DNA. We complemented a truncated kanamycin resistance gene of a bacterial plasmid with a neomycin resistance gene fragment from a gene transfer vector. Optimized transformation conditions allowed us to directly select for kanamycin-resistant bacteria. We cloned numerous proviral flanking fragments from growth factor-independent cell mutants that were obtained after infection with a replication incompetent retroviral vector and identified integrations into the cyclin D2 and several unknown genomic sequences. We anticipate that our method could be adapted to various vector systems that are used to tag and identify genes and to map genomes.
Collapse
Affiliation(s)
- B Fehse
- Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie, an der Universität Hamburg, Martinistrasse 52, 20251 Hamburg, Germany
| | | | | | | | | |
Collapse
|
31
|
Bird KJ, Semus HL, Ruddell A. Resistance to avian leukosis virus lymphomagenesis occurs subsequent to proviral c-myc integration. Oncogene 1999; 18:201-9. [PMID: 9926935 DOI: 10.1038/sj.onc.1202283] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Most chicken strains are highly susceptible to avian leukosis virus (ALV) induction of bursal lymphoma, involving proviral integration within the c-myc proto-oncogene, while certain strains are genetically resistant to lymphomagenesis. A nested PCR assay was developed to analyse the appearance of proviral c-myc integrations after ALV infection of lymphoma-susceptible birds, and to determine whether these integrations arise in lymphoma-resistant birds. Proviral c-myc integrations are detected in bursa and other tissues from 6 day-old lymphoma-susceptible birds infected as embryos. The abundance of bursal cells carrying these integrations increases roughly 40-fold by 35 days of age, indicating that these cells hyperproliferate within the bursal environment. Bursal cells with proviral c-myc integrations also arise soon after infection of lymphoma-resistant embryos. However, these cells expand much more slowly than cells from lymphoma-susceptible birds. Both strains show the same rate of viral infection, so that resistance to lymphomagenesis occurs at a step subsequent to proviral c-myc integration. Proviral c-erbB gene integrations arise at the same frequency in bursa and other tissues of both strains, and they do not increase in abundance during development. These findings indicate that the mechanism of resistance to lymphomagenesis involves specific inhibition of cells with proviral c-myc integrations within the bursa.
Collapse
Affiliation(s)
- K J Bird
- Department of Microbiology and Immunology, University of Rochester, New York, USA
| | | | | |
Collapse
|
32
|
van Agthoven T, van Agthoven TL, Dekker A, van der Spek PJ, Vreede L, Dorssers LC. Identification of BCAR3 by a random search for genes involved in antiestrogen resistance of human breast cancer cells. EMBO J 1998; 17:2799-808. [PMID: 9582273 PMCID: PMC1170620 DOI: 10.1093/emboj/17.10.2799] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The antiestrogen tamoxifen is important in the treatment of hormone-dependent breast cancer, although development of resistance is inevitable. To unravel the molecular mechanisms of antiestrogen resistance, a search for involved genes was initiated. Retrovirus-mediated insertional mutagenesis was applied to human ZR-75-1 breast cancer cells. Infected cells were subjected to tamoxifen selection and a panel of resistant cell clones was established. Screening for a common integration site resulted in the identification of a novel gene designated BCAR3. Transfer of this locus by cell fusion or transfection of the BCAR3 cDNA to ZR75-1 and MCF-7 cells induces antiestrogen resistance. BCAR3 represents a putative SH2 domain-containing protein and is partly homologous to the cell division cycle protein CDC48.
Collapse
MESH Headings
- Amino Acid Sequence
- Animals
- Antineoplastic Agents, Hormonal/pharmacology
- Base Sequence
- Binding Sites
- Breast Neoplasms/drug therapy
- Breast Neoplasms/genetics
- Cell Fusion
- Cloning, Molecular
- DNA, Complementary
- DNA, Neoplasm
- Drug Resistance, Neoplasm/genetics
- Estrogen Antagonists/pharmacology
- Female
- Gene Expression
- Humans
- Molecular Sequence Data
- Protein Biosynthesis
- RNA, Messenger
- Receptors, Cyclic AMP/genetics
- Sequence Homology, Amino Acid
- Tamoxifen/pharmacology
- Transcription, Genetic
- Tumor Cells, Cultured
Collapse
Affiliation(s)
- T van Agthoven
- Department of Molecular Biology, Daniel den Hoed Cancer Center, University Hospital Rotterdam, Rotterdam, The Netherlands
| | | | | | | | | | | |
Collapse
|
33
|
Li M, Xu F, Muller J, Hearing VJ, Gorelik E. Ecotropic C-type retrovirus of B16 melanoma and malignant transformation of normal melanocytes. Int J Cancer 1998; 76:430-6. [PMID: 9579583 DOI: 10.1002/(sici)1097-0215(19980504)76:3<430::aid-ijc23>3.0.co;2-d] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We reported previously that B16,JB/RH and JB/MS melanomas of C57BL/6 mice express the common melanoma-associated antigen (MAA) recognized by MM2-9B6 monoclonal antibody (MAb). This MAA is encoded by the env gene of an ecotropic MuLV-type retrovirus that somatically emerged in melanomas of C57BL/6 mice. The potential role of this melanoma-associated retrovirus (MelARV) in melanoma formation remains unknown and has not been previously investigated. To test this, normal melanocyte lines (melan-a and C57M) of C57BL/6 mice were infected with the MelARV produced by B16BL6 melanoma. Infection of these melanocytes with the MelARV was associated with the appearance of the MAA recognized by MM2-9B6 MAb. Most of the infected melanocyte sublines were able to grow only in the presence of 12-O-tetradecanoylphorbol-13-acetate (TPA). Two infected melanocyte sublines showed morphological changes, were able to grow in the absence of TPA and, after inoculation into C57BL/6 mice, produced rapidly growing, highly pigmented tumors. These new melanomas, derived from the MelARV-infected melan-a and C57M melanocytes, were termed Meli-A1 and Meli-BL, respectively. Southern blot analysis of EcoRI- and HindIII-digested DNAs from these melanomas showed several retroviral insertion sites. One copy of MeIARV was found to be inserted at the end of the 6th leucine domain of the c-maf proto-oncogene, which encodes a basic region/leucine zipper transcription factor related to the AP-1 family that is able to form homodimers or heterodimers with Fos and Jun transcription factors. Our data indicate that c-maf is a common insertion site of MelARV in BL6, Meli-A1 and Meli-BL melanomas, whereas no such insertion site was found in the melanocytes infected with MelARV but not malignantly transformed. Thus, our data imply that the ecotropic MelARV that somatically emerged in B16 and other melanomas of C57BL/6 mice may play a role in malignant transformation.
Collapse
Affiliation(s)
- M Li
- University of Pittsburgh Cancer Institute and Department of Pathology, University of Pittsburgh, PA 15213, USA
| | | | | | | | | |
Collapse
|
34
|
Smith MR, Smith RE, Dunkel I, Hou V, Beemon KL, Hayward WS. Genetic determinant of rapid-onset B-cell lymphoma by avian leukosis virus. J Virol 1997; 71:6534-40. [PMID: 9261373 PMCID: PMC191929 DOI: 10.1128/jvi.71.9.6534-6540.1997] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Infection of 10 day-old chicken embryos with the recombinant avian leukosis virus (ALV) EU-8 induces a high incidence of rapid-onset B-cell lymphoma by insertional activation of the c-myb gene. LR-9, a related ALV with differences from EU-8 in the gag and pol genes, induces rapid-onset lymphoma at only a low incidence. To localize the viral determinant(s) responsible for this biologic difference, we constructed and tested a series of reciprocal chimeras between EU-8 and LR-9 ALVs. The ability to induce rapid-onset lymphoma efficiently was localized to a 925-nucleotide (nt) region of the EU-8 gag gene. Sequence analysis of the region revealed a 42-nt deletion in EU-8 relative to LR-9, as well as some single-nucleotide changes. A mutant virus, delta LR-9, constructed by deleting these 42 nt from LR-9, also induced rapid-onset lymphoma at a high frequency, confirming the biologic significance of this deletion. This deletion removed nt 735 to 776, which lies within a cis-acting RNA element that negatively regulates splicing (NRS). The deletion was shown to cause an increase in splicing efficiency, which may lead to increased production of a truncated myb gene product from an ALV-myb readthrough RNA.
Collapse
Affiliation(s)
- M R Smith
- Department of Medical Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA
| | | | | | | | | | | |
Collapse
|
35
|
Dorssers LC, Veldscholte J. Identification of a novel breast-cancer-anti-estrogen-resistance (BCAR2) locus by cell-fusion-mediated gene transfer in human breast-cancer cells. Int J Cancer 1997; 72:700-5. [PMID: 9259413 DOI: 10.1002/(sici)1097-0215(19970807)72:4<700::aid-ijc24>3.0.co;2-d] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Development of anti-estrogen resistance limits the benefit of endocrine therapy of breast cancer. The mechanistic basis for resistance to the anti-estrogen tamoxifen may involve (epi)genetic alterations within tumor cells. We have initiated a random search for genes allowing estrogen-dependent ZR-75-1 human breast-cancer cells to proliferate in the presence of tamoxifen. The strategy was based on insertion mutagenesis of ZR-75-1 cells using defective retrovirus and subsequent identification of common integration sites. As an alternative approach to identify integration loci involved in anti-estrogen resistance, we have applied cell fusion. Integration regions from lethally irradiated, tamoxifen-resistant cells were transferred to hygromycin B-resistant ZR-75-1 cells. Somatic cell hybrids were established by selection for resistance to G418 (encoded by the integrated virus) and hygromycin B. Individual integration loci were thus separated among different cell hybrids and tested for their role in anti-estrogen resistance. Analysis of a panel of 29 somatic-cell hybrids revealed that tamoxifen resistance co-segregated with only 1 of the 2 integration loci present in the tamoxifen-resistant donor cell line. This locus was further identified as a common integration site in our panel of tamoxifen-resistant cell clones. Our results designate this integration site as the second breast-cancer-anti-estrogen-resistance locus (BCAR2), which most likely contains a gene responsible for the anti-estrogen-resistant phenotype in close proximity to the integrated virus. Our data also imply that individual genes can alter the estrogen dependency of human breast-cancer cells in a dominant manner in vitro.
Collapse
Affiliation(s)
- L C Dorssers
- Department of Molecular Biology, Dr. Daniel den Hoed Cancer Center/University Hospital Rotterdam, The Netherlands.
| | | |
Collapse
|
36
|
Amtoft HW, Sørensen AB, Bareil C, Schmidt J, Luz A, Pedersen FS. Stability of AML1 (core) site enhancer mutations in T lymphomas induced by attenuated SL3-3 murine leukemia virus mutants. J Virol 1997; 71:5080-7. [PMID: 9188573 PMCID: PMC191741 DOI: 10.1128/jvi.71.7.5080-5087.1997] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Murine retrovirus SL3-3 is highly T lymphomagenic. Its pathogenic properties are determined by the transcriptional enhancer of the U3 repeat region which shows preferential activity in T cells. Within the U3 repeats, the major determinant of T-cell specificity has been mapped to binding sites for the AML1 transcription factor family (also known as the core binding factor [CBF], polyomavirus enhancer binding protein 2 [PEBP2], and SL3-3 enhancer factor 1 [SEF-1]). SL3-3 viruses with AML1 site mutations have lost a major determinant of T-cell-specific enhancer function but have been found to retain a lymphomagenic potential, although disease induction is slower than for the SL3-3 wild type. To compare the specificities and mechanisms of disease induction of wild-type and mutant viruses, we have examined lymphomas induced by mutant viruses harboring transversions of three consecutive base pairs critical to AML1 site function (B. Hallberg, J. Schmidt, A. Luz, F. S. Pedersen, and T. Grundström. J. Virol. 65:4177-4181, 1991). Our results show that the mutated AML1 sites are genetically stable during lymphomagenesis and that ecotropic provirus numbers in DNA of tumors induced by wild-type and mutant viruses fall within the same range. Moreover, proviruses were found to be integrated at the c-myc locus in similar proportions of wild-type and mutant SL3-3-induced tumors, and the mutated AML1 sites of proviruses at c-myc are unaltered. In some cases, however, including one c-myc-integrated provirus, a single-base pair change was detected in a second, weaker AML1 binding site. By DNA rearrangement analysis of the T-cell receptor beta-locus, tumors induced by the AML1 site mutants are found to be of the T-cell type. Thus, although the AML1 site mutants have weakened T-cell-specific enhancers they are T-lymphomagenic, and wild-type- and mutant-virus-induced tumor DNAs are similar with respect to the number of overall ecotropic and c-myc-integrated clonal proviruses. The SL3-3 wild-type and AML1 site mutant viruses may therefore induce disease by similar mechanisms.
Collapse
Affiliation(s)
- H W Amtoft
- Department of Molecular and Structural Biology, University of Aarhus, Aarhus C, Denmark
| | | | | | | | | | | |
Collapse
|
37
|
Sørensen AB, Duch M, Amtoft HW, Jørgensen P, Pedersen FS. Sequence tags of provirus integration sites in DNAs of tumors induced by the murine retrovirus SL3-3. J Virol 1996; 70:4063-70. [PMID: 8648744 PMCID: PMC190287 DOI: 10.1128/jvi.70.6.4063-4070.1996] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The murine retrovirus SL3-3 is a potent inducer of T-cell lymphomas when inoculated into susceptible newborn mice. The proviral integration site sequences were surveyed in tumor DNAs by a simple two-step PCR method. From 20 SL3-3-induced tumors a total of 39 provirus-host junctions were amplified and sequenced. Seven showed homology to known sequences. These included the known common integration site c-myc as well as genes not previously identified as targets of provirus integration, namely N-ras and the genes coding for major histocompatibility complex class 11 E-beta, protein kinase C-eta, and T-cell receptor beta-chain. Among these genes, the integrations in c-myc as well as the one in N-ras were found to be clonal. One of the remaining 32 proviral integration site sequences that show no similarities to known sequences may represent a common integration site, as 2 of the 20 tumors demonstrated clonal provirus insertion into this region.
Collapse
MESH Headings
- Animals
- Base Sequence
- DNA, Neoplasm/genetics
- Genes, MHC Class II
- Genes, myc
- Genes, ras
- Leukemia Virus, Murine/genetics
- Lymphoma, T-Cell/genetics
- Lymphoma, T-Cell/virology
- Mice
- Molecular Sequence Data
- Polymerase Chain Reaction
- Protein Kinase C/genetics
- Protein Serine-Threonine Kinases
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins c-pim-1
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Repetitive Sequences, Nucleic Acid
- Virus Integration
Collapse
Affiliation(s)
- A B Sørensen
- Department of Molecular and Structural Biology, University of Aarhus, Denmark
| | | | | | | | | |
Collapse
|
38
|
Chou KS, Okayama A, Su IJ, Lee TH, Essex M. Preferred nucleotide sequence at the integration target site of human T-cell leukemia virus type I from patients with adult T-cell leukemia. Int J Cancer 1996; 65:20-4. [PMID: 8543390 DOI: 10.1002/(sici)1097-0215(19960103)65:1<20::aid-ijc4>3.0.co;2-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Human T-cell leukemia virus type I (HTLV-I) is etiologically associated with adult T-cell leukemia/lymphoma (ATL). We cloned and sequenced host DNA adjacent to the long terminal repeats of HTLV-I from uncultured leukemic cells of 4 ATL patients. The region flanking the provirus was generally A/T-rich (60-64% A/T), and a nucleotide composition bias was noticed when sequences within 25 bp on both sides of the integration target site were analyzed. In the 6-bp direct repeat, both end positions are preferentially occupied by G/C, whereas the middle positions are preferentially occupied by A/T. Furthermore, AA or TT dinucleotides are frequently present on each side adjacent to the center of the direct repeat. Our finding suggests preferential integration target sites of HTLV-I in the host genome. Further study is warranted to determine whether each of the target sequence preference is a general property of HTLV-I integration or may be associated with the leukemogenesis of ATL.
Collapse
Affiliation(s)
- K S Chou
- Department of Cancer Biology, Harvard School of Public Health, Boston, MA 02115, USA
| | | | | | | | | |
Collapse
|
39
|
Wong KK, Chatterjee S. Adeno-associated virus based vectors as antivirals. Curr Top Microbiol Immunol 1996; 218:145-70. [PMID: 8794250 DOI: 10.1007/978-3-642-80207-2_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- K K Wong
- Department of Hematology, City of Hope National Medical Center, Duarte, CA 91010, USA
| | | |
Collapse
|
40
|
Rassart E, Houde J, Denicourt C, Ru M, Barat C, Edouard E, Poliquin L, Bergeron D. Molecular analysis and characterization of two myeloid leukemia inducing murine retroviruses. Curr Top Microbiol Immunol 1996; 211:201-10. [PMID: 8585951 DOI: 10.1007/978-3-642-85232-9_20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- E Rassart
- Département des sciences biologiques, Université du Québec à Montréal, Canada
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Affiliation(s)
- J P Trempe
- Department of Biochemistry and Molecular Biology, Medical College of Ohio, Toledo 43699, USA
| |
Collapse
|
42
|
Steinhuber S, Brack M, Hunsmann G, Schwelberger H, Dierich MP, Vogetseder W. Distribution of human endogenous retrovirus HERV-K genomes in humans and different primates. Hum Genet 1995; 96:188-92. [PMID: 7635468 DOI: 10.1007/bf00207377] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The distribution of the human endogenous retrovirus (HERV)-K genome was investigated by Southern-blot analyses using a HERV-K-env DNA probe. With the exception of one DNA-sample, obtained from a Chinese individual in whom an amplification of HERV-K was detected, Southern-blot analyses yielded identical hybridization patterns with DNA from peripheral blood lymphocytes of 37 normal healthy blood donors, with DNA from six tumor cell lines, or with 23 DNA samples prepared from various carcinoma tissues. To elucidate whether the integration of HERV-K genomes into the primate lineage occurred as a single event or as an integration with later expansion, we further examined the evolutionary history of HERV-K by Southern blot analyses with DNA samples from different primate species. We detected HERV-K genomes in Macaca mulatta and Macaca silenus, which represent Old World monkeys, but not in prosimians (Galago demidovii) and New World monkeys, represented by Saguinus fuscicollis, Saguinus oedipus, and Callithrix iacchus. Thus, we assume that the infection of the primate lineage with HERV-K had occurred after the divergence of New World and Old World monkeys, but before the evolutionary expansion of large hominoids. In contrast to the apparent lack of HERV-K-env sequences in DNA from tissue of the New World monkey Saguinus oedipus (cotton-top marmoset), we found HERV-K-DNA in the B95-8 cell-line, which is a Saguinus oedipus leukocyte cell-line, immortalized in vitro by Epstein-Barr virus (EBV) and cultivated in human cells. It may be speculated that HERV-K-DNA or HERV-K-particles were introduced into these cells during in vitro transformation with EBV.
Collapse
Affiliation(s)
- S Steinhuber
- Institut für Hygiene, Leopold-Franzens-Universität, Innsbruck, Austria
| | | | | | | | | | | |
Collapse
|
43
|
Abstract
One of the more interesting developments in herpesvirus evolution concerns the acquisition of novel, non-ubiquitous herpesvirus genes. A number of these are related to known cellular genes. How did herpesviruses acquire such genes? Our recent demonstration of retrovirus integration into herpesviruses suggests a potentially important role for retrotransposition in herpesvirus evolution and in the acquisition of novel genes, cellular in origin. Herpesvirus genome development has been characterized by a number of structural and evolutionary properties that support this proposal. We first discuss the evidence for retroviral integration into herpesviruses. The functional significance of this phenomenon is presently unclear. However, in the broader context of retrotransposition, a number of attractive features serve to explain the capture of structural and regulatory elements throughout herpesvirus evolution. These possibilities are discussed in detail.
Collapse
Affiliation(s)
- P Brunovskis
- Department of Molecular Biology and Microbiology, Case-Western Reserve University, Cleveland, OH 44106, USA
| | | |
Collapse
|
44
|
Hannemann J, Hara T, Kawai M, Miyajima A, Ostertag W, Stocking C. Sequential mutations in the interleukin-3 (IL3)/granulocyte-macrophage colony-stimulating factor/IL5 receptor beta-subunit genes are necessary for the complete conversion to growth autonomy mediated by a truncated beta C subunit. Mol Cell Biol 1995; 15:2402-12. [PMID: 7739524 PMCID: PMC230469 DOI: 10.1128/mcb.15.5.2402] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
An amino-terminally truncated beta C receptor (beta C-R) subunit of the interleukin-3 (IL3)/granulocyte-macrophage colony-stimulating factor/IL5 receptor complex mediates factor-independent and tumorigenic growth in two spontaneous mutants of a promyelocytic cell line. The constitutive activation of the JAK2 protein kinase in these mutants confirms that signaling occurs through the truncated receptor protein. Noteworthily, in addition to a 10-kb deletion in the beta C-R subunit gene encoding the truncated receptor, several secondary and independent mutations that result in the deletion or functional inactivation of the allelic beta C-R subunit and the closely related beta IL3-R subunit genes were observed in both mutants, suggesting that such mutations are necessary for the full oncogenic penetrance of the truncated beta C-R subunit. Reversion of these mutations by the expression of the wild-type beta C-R in the two mutants resulted in a fivefold decrease in cloning efficiency of the mutants in the absence of IL3, confirming a functional interaction between the wild-type and truncated proteins. Furthermore, expression of the truncated beta C-R subunit in factor-dependent myeloid cells did not immediately render the cells autonomous but increased the spontaneous frequency to factor-independent growth by 4 orders of magnitude. Implications for both leukemogenic progression and receptor-subunit interaction and signaling are discussed.
Collapse
Affiliation(s)
- J Hannemann
- Abteilung der Zell- und Virusgenetik, Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie, Hamburg, Germany
| | | | | | | | | | | |
Collapse
|
45
|
Morrison HL, Soni B, Lenz J. Long terminal repeat enhancer core sequences in proviruses adjacent to c-myc in T-cell lymphomas induced by a murine retrovirus. J Virol 1995; 69:446-55. [PMID: 7983741 PMCID: PMC188593 DOI: 10.1128/jvi.69.1.446-455.1995] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The transcriptional enhancer in the long terminal repeat (LTR) of the T-lymphomagenic retrovirus SL3-3 differs from that of the nonleukemogenic virus Akv at several sites, including a single base pair difference in an element termed the enhancer core. Mutation of this T-A base pair to the C-G C-G sequence found in Akv significantly attenuated the leukemogenicity of SL3-3. Thus, this difference is important for viral leukemogenicity. Since Akv is an endogenous virus, this suggests that the C-G in its core is an adaptation to being minimally pathogenic. Most tumors that occurred in mice inoculated with the mutant virus, called SAA, contained proviruses with reversion or potential suppressor mutations in the enhancer core. We also found that the 72-bp tandem repeats constituting the viral enhancer could vary in number. Most tumors contained mixtures of proviruses with various numbers of 72-bp units, usually between one and four. Variation in repeat number was most likely due to recombination events involving template misalignment during viral replication. Thus, two processes during viral replication, misincorporation and recombination, combined to alter LTR enhancer structure and generate more pathogenic variants from the mutant virus. In SAA-induced tumors, enhancers of proviruses adjacent to c-myc had the largest number of core reversion or suppressor mutations of all of the viral enhancers in those tumors. This observation was consistent with the hypothesis that one function of the LTR enhancers in leukemogenesis is to activate proto-oncogenes such as c-myc.
Collapse
Affiliation(s)
- H L Morrison
- Department of Molecular Genetics, Albert Einstein College of Medicine, Bronx, New York 10461
| | | | | |
Collapse
|
46
|
Jiang X, Villeneuve L, Turmel C, Kozak CA, Jolicoeur P. The Myb and Ahi-1 genes are physically very closely linked on mouse chromosome 10. Mamm Genome 1994; 5:142-8. [PMID: 7911043 DOI: 10.1007/bf00352344] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Ahi-1 has previously been identified as a common helper provirus integration site on mouse Chromosome (Chr) 10 in 16% of Abelson pre-B-cell lymphomas and shown to be closely linked to the Myb protooncogene. By using long-range restriction mapping, we have mapped the Myb and Ahi-1 regions within a 120-kbp DNA fragment. The Ahi-1 region is located approximately 35 kbp downstream of the Myb gene. A further confirmation of this finding was obtained by screening a mouse YAC library. The three positive clones obtained contained both the Myb and Ahi-1 gene sequences. To test whether provirus integration in the Ahi-1 region enhances the expression of Myb by a cis-acting mechanism, we have also examined Myb gene expression in A-MuLV-induced pre-B-lymphomas. Our data have revealed that there is no clear evidence for such activation in the tumors we have tested, indicating that provirus insertion in the Ahi-1 region is activating a novel gene, apparently involved in tumor formation.
Collapse
Affiliation(s)
- X Jiang
- Laboratory of Molecular Biology, Clinical Research Institute of Montreal, Quebec, Canada
| | | | | | | | | |
Collapse
|
47
|
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
|
48
|
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
|
49
|
Raineri I, Senn HP. HIV-1 promotor insertion revealed by selective detection of chimeric provirus-host gene transcripts. Nucleic Acids Res 1992; 20:6261-6. [PMID: 1475186 PMCID: PMC334514 DOI: 10.1093/nar/20.23.6261] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
To study host gene activation by retroviral promotor insertion, a polymerase chain reaction (PCR) assay was developed. This method allows a sensitive and selective detection of chimeric provirus-host gene transcripts, hallmarks of insertional activation events, which does not rely on an induction of tumor cell growth. We analysed HIV-1 infected cells of a CD4+ T-cell line (H9), infected peripheral blood mononuclear cells and cells in broncho-alveolar washes of AIDS patients. In each case, a variety of chimeric mRNA molecules were detected using a PCR amplification reaction and 5' primers specific to the HIV-1 LTR and 3' primers specific to poly A of mRNA. In infected H9 lymphocytes, a mRNA was identified encoding a putative protein of 145 amino-acids that was not expressed in uninfected H9 cells. This shows for the first time that HIV-1 can activate transcription of host cellular genes by promotor insertion in a fashion similar to slow-transforming avian and murine retroviruses.
Collapse
Affiliation(s)
- I Raineri
- Institute for Medical Microbiology, University of Basel, Switzerland
| | | |
Collapse
|
50
|
Boerkoel CF, Kung HJ. Transcriptional interaction between retroviral long terminal repeats (LTRs): mechanism of 5' LTR suppression and 3' LTR promoter activation of c-myc in avian B-cell lymphomas. J Virol 1992; 66:4814-23. [PMID: 1321271 PMCID: PMC241309 DOI: 10.1128/jvi.66.8.4814-4823.1992] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Chicken syncytial viruses induce bursal lymphomas by integrating into the c-myc locus and activating myc expression by 3' long terminal repeat (LTR) promoter insertion. In contrast to wild-type proviruses, in which transcription initiates predominantly in the 5'LTR, these myc-associated proviruses exhibit a predominance of transcription from the 3' LTR and little transcription from the 5' LTR. Most of these proviruses contain deletions within the 5' end of their genome that spare the 5' LTR. We report the identification of a 0.3-kb viral leader sequence that modulates 5' and 3' LTR transcriptional activities. In the presence of this sequence, transcription from the 5' LTR predominates, but in its absence, the 3' LTR promoter becomes activated, resulting in a high level of myc expression. This viral sequence does not behave like a classical enhancer; it activates transcription only when located downstream from the promoter and in the sense orientation. In this regard, it resembles the recently described human immunodeficiency virus RNA enhancer. This study suggests that retroviruses contain internal sequences which directionally activate the 5' LTR promoter to facilitate transcription of the viral genome and that deletion of these sequences is one step in the activation of the 3' LTR of myc-associated proviruses in avian bursal lymphomas.
Collapse
MESH Headings
- Animals
- Base Sequence
- Blotting, Northern
- Cell Line
- Cell Nucleus/physiology
- Cells, Cultured
- Chick Embryo
- Chickens
- Chloramphenicol O-Acetyltransferase/genetics
- Chloramphenicol O-Acetyltransferase/metabolism
- Dogs
- Genes, myc
- Lymphoma, B-Cell/microbiology
- Molecular Sequence Data
- Nucleic Acid Conformation
- Plasmids
- Promoter Regions, Genetic
- Proviruses/genetics
- RNA, Messenger/genetics
- RNA, Messenger/isolation & purification
- RNA, Viral/genetics
- RNA, Viral/isolation & purification
- Repetitive Sequences, Nucleic Acid
- Restriction Mapping
- Reticuloendotheliosis virus/genetics
- Transcription, Genetic
- Transfection
Collapse
Affiliation(s)
- C F Boerkoel
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | | |
Collapse
|