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Kim S, Rusmevichientong A, Dong B, Remenyi R, Silverman RH, Chow SA. Fidelity of target site duplication and sequence preference during integration of xenotropic murine leukemia virus-related virus. PLoS One 2010; 5:e10255. [PMID: 20421928 PMCID: PMC2857682 DOI: 10.1371/journal.pone.0010255] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2010] [Accepted: 03/28/2010] [Indexed: 11/18/2022] Open
Abstract
Xenotropic murine leukemia virus (MLV)-related virus (XMRV) is a new human retrovirus associated with prostate cancer and chronic fatigue syndrome. The causal relationship of XMRV infection to human disease and the mechanism of pathogenicity have not been established. During retrovirus replication, integration of the cDNA copy of the viral RNA genome into the host cell chromosome is an essential step and involves coordinated joining of the two ends of the linear viral DNA into staggered sites on target DNA. Correct integration produces proviruses that are flanked by a short direct repeat, which varies from 4 to 6 bp among the retroviruses but is invariant for each particular retrovirus. Uncoordinated joining of the two viral DNA ends into target DNA can cause insertions, deletions, or other genomic alterations at the integration site. To determine the fidelity of XMRV integration, cells infected with XMRV were clonally expanded and DNA sequences at the viral-host DNA junctions were determined and analyzed. We found that a majority of the provirus ends were correctly processed and flanked by a 4-bp direct repeat of host DNA. A weak consensus sequence was also detected at the XMRV integration sites. We conclude that integration of XMRV DNA involves a coordinated joining of two viral DNA ends that are spaced 4 bp apart on the target DNA and proceeds with high fidelity.
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Affiliation(s)
- Sanggu Kim
- Biomedical Engineering Interdepartmental Program, University of California Los Angeles, Los Angeles, California, United States of America
| | - Alice Rusmevichientong
- Department of Molecular and Medical Pharmacology, Molecular Biology Institute, and University of California Los Angeles AIDS Institute, University of California Los Angeles School of Medicine, Los Angeles, California, United States of America
| | - Beihua Dong
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Roland Remenyi
- Department of Molecular and Medical Pharmacology, Molecular Biology Institute, and University of California Los Angeles AIDS Institute, University of California Los Angeles School of Medicine, Los Angeles, California, United States of America
| | - Robert H. Silverman
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Samson A. Chow
- Biomedical Engineering Interdepartmental Program, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Molecular and Medical Pharmacology, Molecular Biology Institute, and University of California Los Angeles AIDS Institute, University of California Los Angeles School of Medicine, Los Angeles, California, United States of America
- * E-mail:
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Age-dependent tolerance to an endogenous tumor-associated antigen. Vaccine 2008; 26:1863-1873. [PMID: 18329760 DOI: 10.1016/j.vaccine.2008.01.052] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Revised: 01/25/2008] [Accepted: 01/29/2008] [Indexed: 11/20/2022]
Abstract
Immunologic tolerance to endogenous antigens reduces antitumor responses. Gp70 is an endogenous tumor-associated antigen (TAA) of the BALB/c-derived colon carcinoma CT26. We found that expression of gp70 mRNA is detectable in tissues of mice 8 months of age and older. We showed that expression of gp70 establishes immunologic tolerance and affects antitumor immunity in a similarly age-dependent manner using gp70-deficient mice. We found that tumors grew in all gp70-sufficient mice, while approximately half of gp70-deficient mice controlled tumor growth with endogenous T-cell responses. Protection in gp70-deficient mice correlated with more robust gp70-specific CTL responses, and increased numbers and avidity of responding antigen-specific T cells after vaccination. We conclude that immunosurveillance may decline with age due to increased or de novo peripheral expression of endogenous TAAs.
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French NS, Norton JD. Structure and functional properties of mouse VL30 retrotransposons. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1352:33-47. [PMID: 9177481 DOI: 10.1016/s0167-4781(97)00009-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- N S French
- CRC Department of Gene Regulation, Paterson Institute for Cancer Research, Christie Hospital (NHS) Trust, Manchester, UK
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Nilsson M, Bohm S. Inducible and cell type-specific expression of VL30 U3 subgroups correlate with their enhancer design. J Virol 1994; 68:276-88. [PMID: 8254739 PMCID: PMC236287 DOI: 10.1128/jvi.68.1.276-288.1994] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The murine VL30 elements constitute one family of retrotransposons represented in 100 to 200 copies that are dispersed among the mouse chromosomes. On the basis of sequence homology, we have subdivided mouse VL30 members into four distinct U3 subgroups. The use of subgroup-specific probes in Northern (RNA) blot analyses shows that individual VL30 U3 subgroups are expressed in a tissue-specific manner. We show by in situ hybridization of mouse skin treated with 12-O-tetradecanoylphorbol-13-acetate (TPA) that VL30 expression is induced in epidermal keratinocytes but not in dermal fibroblasts. Transient transfections of reporter gene plasmids together with in vitro binding analysis indicate that TPA-induced VL30 transcription specific for keratinocytes is mediated by two cooperating sequence motifs in juxtaposed position. One sequence motif is shown to constitutively bind CREB- and Jun-related proteins in both keratinocytes and fibroblasts, whereas the other is a target for TPA-induced c-Rel/p65(NF-kappa B)-binding activity specifically in keratinocytes. These binding sites are found to be conserved within U3 subgroups and individual U3 regions showing induced expression in TPA-treated mouse epidermis. These results together with a sequence comparison between different U3 subgroups indicate that cell type-specific activity of transcription factors known to regulate VL30 transcription and the presence or absence of their cognate binding sites within individual U3 regions determine inducible and cell type-specific VL30 expression. The variable VL30 U3 regions might thus be useful tools to study inducible and cell type-specific transcription in many different cell systems.
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Affiliation(s)
- M Nilsson
- Center for Nutrition and Toxicology, Karolinska Institute, NOVUM, Huddinge, Sweden
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Sørensen AB, Duch M, Jørgensen P, Pedersen FS. Amplification and sequence analysis of DNA flanking integrated proviruses by a simple two-step polymerase chain reaction method. J Virol 1993; 67:7118-24. [PMID: 8230434 PMCID: PMC238173 DOI: 10.1128/jvi.67.12.7118-7124.1993] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We describe a two-step polymerase chain reaction method that can be used for the amplification of cellular DNA sequences adjacent to an integrated retroviral provirus. The technique involves a partly degenerate, arbitrary primer that will hybridize in the provirus-flanking cellular DNA. By using this primer in combination with a biotinylated provirus-specific primer, a provirus-cellular DNA junction fragment can be isolated from the nonspecific amplification products by using streptavidin-coated magnetic beads. A second amplification employing a nested provirus-specific primer and a biotinylated nondegenerate primer derived from the partly degenerate primer followed by purification with streptavidin-coated beads enhances the specificity and the efficiency of recovery of a fragment(s) containing the unknown flanking sequences. In addition to being relevant in studies of viral integration sites, the method should be generally useful to analyze DNA sequences either upstream or downstream from a known sequence.
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Affiliation(s)
- A B Sørensen
- Department of Molecular Biology, University of Aarhus, Denmark
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Bohm S. Identification of protein-binding sequences mediating constitutive and 12-O-tetradecanoylphorbol-13-acetate-induced VL30 transcription in cultured mouse and human keratinocytes. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54304-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Timmons PM, Brickell PM, Latchman DS, Rigby PW. Activation of endogenous retroviral transcription in SV40-transformed mouse cells. Nucleic Acids Res 1991; 19:7215-8. [PMID: 1662812 PMCID: PMC332582 DOI: 10.1093/nar/19.25.7215] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We have previously isolated a number of cDNA clones that correspond to mRNAs present at higher levels in SV40-transformed cells than in the untransformed parental cells (Scott, M.R.D., Westphal, K.-H. and Rigby, P.W.J. (1983) Cell 34, 557-567). We have now determined the nucleotide sequence of the archetypal Set 2 clone, pAG59, and can thus identify it as corresponding to the env gene of the endogenous, ecotropic C-type retrovirus of Balb/c mice, Emv-1. We have shown that in the subset of SV40-transformed cells that express the provirus both of the proteins encoded by env, gp70 and p15E, are synthesised and that the former is displayed on the cell surface. We discuss the significance of these observations for the biology of SV40 transformation.
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Affiliation(s)
- P M Timmons
- Department of Biochemistry, Imperial College of Science and Technology, London, UK
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Silver J, Keerikatte V. Novel use of polymerase chain reaction to amplify cellular DNA adjacent to an integrated provirus. J Virol 1989; 63:1924-8. [PMID: 2704070 PMCID: PMC250604 DOI: 10.1128/jvi.63.5.1924-1928.1989] [Citation(s) in RCA: 134] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We describe a modification of the polymerase chain reaction technique which allows amplification of cellular DNA adjacent to an integrated provirus given sequence information for the provirus only. The modified technique should be generally useful for studies of insertional mutagenesis and other situations in which one wishes to isolate DNA adjacent to a region of known sequence.
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Affiliation(s)
- J Silver
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892
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Sithanandam G, Rapp UR. A single point mutation in the envelope gene is responsible for replication and XC fusion deficiency of the endogenous ecotropic C3H/He murine leukemia virus and for its repair in culture. J Virol 1988; 62:932-43. [PMID: 2828688 PMCID: PMC253652 DOI: 10.1128/jvi.62.3.932-943.1988] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The molecular basis has been determined for differences in infectivity and XC phenotype of endogenous ecotropic murine leukemia virus of the low-leukemia mouse strain C3H/He, its relative in the high-leukemia mouse strain AKR, and highly infectious, XC-positive C3H virus variants selected in vitro. Endogenous ecotropic type C virus induced by iododeoxyuridine from the nontransformed C3H/10T1/2 cell line is XC negative and replication deficient. In contrast, viruses produced late after iododeoxyuridine induction in chemically transformed C3H/10T1/2 cells (MCA5) are XC positive and infectious. XC-negative viruses can be converted to XC-positive viruses by being grown in certain transformed cell lines. We have cloned the endogenous ecotropic provirus of C3H/He from MCA5 cells, which is XC negative and replication deficient, as well as two XC-positive C3H proviruses derived by in vitro conversion. Fragment exchange between the XC-negative molecular clone p110 and the XC-positive AKR virus clone p623 revealed that the defect in p110 lies 3' of the SalI site located in the pol region. Nucleotide sequencing established that the C3H p110 provirus was integrated within the R region of an endogenous VL30 long terminal repeat (LTR) in reverse orientation and that the virus differed from the infectious AKR p623 provirus by a point mutation, substituting Lys for Arg at the potential precursor cleavage site for gp70 and p15E. In vitro-converted XC-positive C3H proviral clones 3211 and 4211 are identical to XC-negative C3H p110, except that they have Arg at this site and the normal cleavage site is thus regenerated in these clones. The XC-negative C3H p110 was blocked in processing of Pr85env, whereas clones 3211 and 4211 had normal cleavage of the env precursor into gp70. Both the XC-negative C3H provirus and the in vitro-converted XC-positive C3H proviruses had a single copy of a 99-base-pair enhancer element in the LTR, whereas two copies of this sequence are present in the AKR proviral LTR. Substitution of Arg for Lys at the envelope precursor processing site of C3H p110 by site-directed mutagenesis is sufficient by itself to convert the virus to the XC-positive replication-competent phenotype. Thus, we have established that a single point mutation at the processing site of the envelope precursor protein Pr85 is responsible for the difference in the infectivity and XC phenotype of endogenous ecotropic murine leukemia virus from C3H/He and AKR mice and that the basis for in vitro conversion is a mutation at this site.
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Affiliation(s)
- G Sithanandam
- Laboratory of Viral Carcinogenesis, National Cancer Institute, Frederick, Maryland 21701
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King SR, Berson BJ, Risser R. Mechanism of interaction between endogenous ecotropic murine leukemia viruses in (BALB/c X C57BL/6) hybrid cells. Virology 1988; 162:1-11. [PMID: 2447699 DOI: 10.1016/0042-6822(88)90388-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The germline ecotropic murine leukemia (MuLV) proviruses of BALB/c and C57BL/6 (B6) mice were analyzed to determine the molecular basis of low virus expression in these mouse strains and to determine the mechanism of interaction of these two proviruses. Previous work had demonstrated that the BALB/c endogenous ecotropic provirus was infectious but unable to induce XC cell syncytia formation, and that induced (BALB/c X B6) hybrid cells expressed 10- to 50-fold more XC syncytia than induced parental cells. Two independently isolated DNA clones of the B6 endogenous ecotropic provirus were noninfectious following transfection into cells, and cell lines that expressed this viral genome produced noninfectious MuLV. Nucleotide sequencing of the mutant region of the B6 provirus indicated that the defective nature of this provirus resulted from an amino acid substitution of proline for alanine in the central portion of reverse transcriptase. From the analysis of the virus produced by induced hybrid cells, and the patterns of steady-state viral RNA in induced cells, we propose that the enhanced XC cell syncytia formation observed in hybrid cells is due to trans-complementation of viral proteins and not viral recombination or trans-activation of viral genome expression.
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Affiliation(s)
- S R King
- Department of Immunology and Microbiology, Wayne State University, School of Medicine, Detroit, Michigan 48201
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