51
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Hasegawa M, Yamaguchi S, Aizawa S, Ikeda H, Tatsumi K, Noda Y, Hirokawa K, Kitagawa M. Resistance against Friend leukemia virus-induced leukemogenesis in DNA-dependent protein kinase (DNA-PK)-deficient scid mice associated with defective viral integration at the Spi-1 and Fli-1 site. Leuk Res 2005; 29:933-42. [PMID: 15978944 DOI: 10.1016/j.leukres.2005.01.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2004] [Accepted: 01/22/2005] [Indexed: 11/23/2022]
Abstract
Retroviral DNA integration is mediated by the viral protein integrase. However, elements of the host DNA repair machinery such as the phosphatidylinositol 3-kinase (PI-3K)-related protein kinase family system would play a role in the integration of viral DNA into the host DNA. Here, we show that a host PI-3K-related protein kinase, DNA-dependent protein kinase (DNA-PK), plays a role in the specific integration of retroviral DNA and induction of retroviral diseases in vivo. DNA-PK-deficient scid mice inoculated with Friend leukemia virus (FLV) exhibited a random integration into their genomic DNA and expressed the viral envelope protein gp70. However, the specific integration of FLV at Spi-1 or Fli-1 sites did not occur in association with the significant resistance of scid mice to FLV-induced leukemogenesis. In contrast, the knockout of another member of the PI-3K-related protein kinase family, encoded by the ataxia telangiectasia mutated (ATM) gene, resulted in mice as sensitive to FLV-induced leukemogenesis as the wild type mice. FLV was specifically integrated into the DNA at Spi-1 and Fli-1 sites with significant expression of these transcription factors. These findings indicated that DNA-PK would be essential for controlling the in vivo integration of FLV at specific sites as well as the susceptibility to FLV-induced leukemogenesis.
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MESH Headings
- Animals
- Apoptosis/immunology
- Bone Marrow Transplantation
- DNA, Viral/genetics
- DNA-Activated Protein Kinase
- DNA-Binding Proteins/deficiency
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Drug Resistance, Viral
- Friend murine leukemia virus/genetics
- Friend murine leukemia virus/immunology
- Genes, p53/immunology
- Leukemia, Experimental/genetics
- Leukemia, Experimental/immunology
- Leukemia, Experimental/virology
- Lymphocytes/immunology
- Lymphocytes/virology
- Male
- Mice
- Mice, Inbred C3H
- Mice, Knockout
- Mice, SCID
- Protein Serine-Threonine Kinases/deficiency
- Protein Serine-Threonine Kinases/genetics
- Proto-Oncogene Protein c-fli-1
- Proto-Oncogene Proteins/metabolism
- Retroviridae Infections/genetics
- Retroviridae Proteins, Oncogenic/genetics
- Retroviridae Proteins, Oncogenic/immunology
- Sp1 Transcription Factor/metabolism
- Spleen/chemistry
- Spleen/immunology
- Spleen/virology
- Survival Analysis
- Trans-Activators/metabolism
- Viral Envelope Proteins/genetics
- Viral Envelope Proteins/immunology
- Virus Integration
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Affiliation(s)
- Maki Hasegawa
- Department of Comprehensive Pathology, Aging and Developmental Sciences, Tokyo Medical and Dental University, Graduate School, 1-5-45 Yushima, Bunkyo-ku, Tokyo 13-8519, Japan
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52
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Kameoka M, Nukuzuma S, Itaya A, Tanaka Y, Ota K, Inada Y, Ikuta K, Yoshihara K. Poly(ADP-ribose)polymerase-1 is required for integration of the human immunodeficiency virus type 1 genome near centromeric alphoid DNA in human and murine cells. Biochem Biophys Res Commun 2005; 334:412-7. [PMID: 16002043 DOI: 10.1016/j.bbrc.2005.06.104] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2005] [Accepted: 06/20/2005] [Indexed: 11/25/2022]
Abstract
This study examined the efficiency of human immunodeficiency virus type 1 (HIV-1) integration in poly(ADP-ribose)polymerase-1 (PARP-1)-deficient murine cells and in human cell lines transfected with small interfering RNA against PARP-1 (PARP-1 siRNA). To semi-quantify the amount of integrated HIV-1 genome, real-time nested PCR was carried out using primers specific for Alu and alphoid DNA combined with primers for the HIV-1 genome. The results showed that the integration efficiency of the HIV-1 genome near Alu DNA, which is randomly distributed in the chromosome, is reduced in PARP-1-deficient murine cells, but not in PARP-1 siRNA-transfected human cells. By contrast, the integration efficiency of the HIV-1 genome near alphoid DNA, which is localized in the centromere region, is significantly reduced in PARP-1-deficient murine cells and in PARP-1 siRNA-transfected human cells. These results suggest that PARP-1 is required for HIV-1 integration near the centromere region both in human and murine cells.
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Affiliation(s)
- Masanori Kameoka
- Department of Biochemistry, Nara Medical University School of Medicine, Kashihara, Nara 634-8521, Japan.
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53
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Nunnari G, Argyris E, Fang J, Mehlman KE, Pomerantz RJ, Daniel R. Inhibition of HIV-1 replication by caffeine and caffeine-related methylxanthines. Virology 2005; 335:177-84. [PMID: 15840517 DOI: 10.1016/j.virol.2005.02.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2004] [Revised: 02/15/2005] [Accepted: 02/23/2005] [Indexed: 01/06/2023]
Abstract
Human immunodeficiency virus type I (HIV-1) DNA integration is an essential step of viral replication. We have suggested recently that this stage of HIV-1 life-cycle triggers a cellular DNA damage response and requires cellular DNA repair proteins for its completion. These include DNA-PK (DNA-dependent protein kinase), ATR (ataxia telangiectasia and Rad3-related), and, at least in some circumstances, ATM (ataxia telangiectasia mutated). Host cell proteins may constitute an attractive target for anti-HIV-1 therapeutics, since development of drug resistance against compounds targeting these cellular cofactor proteins is unlikely. In this study, we show that an inhibitor of ATR and ATM kinases, caffeine, can suppress replication of infectious HIV-1 strains, and provide evidence that caffeine exerts its inhibitory effect at the integration step of the HIV-1 life-cycle. We also demonstrate that caffeine-related methylxanthines including the clinically used compound, theophylline, act at the same step of the HIV-1 life-cycle as caffeine and efficiently inhibit HIV-1 replication in primary human cells. These data reveal the feasibility of therapeutic approaches targeting host cell proteins and further support the hypothesis that ATR and ATM proteins are involved in retroviral DNA integration.
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Affiliation(s)
- Giuseppe Nunnari
- The Dorrance H. Hamilton Laboratories, Center for Human Virology and Biodefense, Division of Infectious Diseases and Environmental Medicine, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
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54
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Ariumi Y, Turelli P, Masutani M, Trono D. DNA damage sensors ATM, ATR, DNA-PKcs, and PARP-1 are dispensable for human immunodeficiency virus type 1 integration. J Virol 2005; 79:2973-8. [PMID: 15709017 PMCID: PMC548471 DOI: 10.1128/jvi.79.5.2973-2978.2005] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Integration of a DNA copy of the viral RNA genome is a crucial step in the life cycle of human immunodeficiency virus type 1 (HIV-1) and other retroviruses. While the virally encoded integrase is key to this process, cellular factors yet to be characterized are suspected to participate in its completion. DNA damage sensors such as ATM (ataxia-telangiectasia mutated), ATR (ATM- and Rad3-related), DNA-PK (DNA-dependent protein kinase), and PARP-1 [poly(ADP-ribose) polymerase 1] play central roles in responses to various forms of DNA injury and as such could facilitate HIV integration. To test this hypothesis, we examined the susceptibility to infection with wild-type HIV-1 and to transduction with a vesicular stomatitis virus G protein (VSV-G)-pseudotyped HIV-1-derived lentiviral vector of human cells stably expressing small interfering RNAs against ATM, ATR, and PARP-1. We found that integration normally occurred in these knockdown cells. Similarly, the VSV-G-pseudotyped HIV-1-based vector could effectively transduce ATM and PARP-1 knockout mouse cells as well as human cells deficient for DNA-PK. Finally, treatment of target cells with the ATM and ATR inhibitors caffeine and wortmannin was without effect in these infectivity assays. We conclude that the DNA repair enzymes ATM, ATR, DNA-PKcs, and PARP-1 are not essential for HIV-1 integration.
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Affiliation(s)
- Yasuo Ariumi
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, 1211, Geneva 4, Switzerland
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55
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Weitzman MD, Carson CT, Schwartz RA, Lilley CE. Interactions of viruses with the cellular DNA repair machinery. DNA Repair (Amst) 2005; 3:1165-73. [PMID: 15279805 DOI: 10.1016/j.dnarep.2004.03.018] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Mammalian cells are equipped with complex machinery to monitor and repair damaged DNA. In addition to responding to breaks in cellular DNA, recent studies have revealed that the DNA repair machinery also recognizes viral genetic material. We review some examples that highlight the different strategies that viruses have developed to interact with the host DNA repair apparatus. While adenovirus (Ad) inactivates the host machinery to prevent signaling and concatemerization of the viral genome, other viruses may utilize DNA repair to their own advantage. Viral interactions with the repair machinery can also have detrimental consequences for the host cells and their ability to maintain the integrity of the host genome. Exploring the interactions between viruses and the host DNA repair machinery has revealed novel host responses to virus infections and has provided new tools to study the DNA damage response.
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Affiliation(s)
- Matthew D Weitzman
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA.
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56
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Dehart JL, Andersen JL, Zimmerman ES, Ardon O, An DS, Blackett J, Kim B, Planelles V. The ataxia telangiectasia-mutated and Rad3-related protein is dispensable for retroviral integration. J Virol 2005; 79:1389-96. [PMID: 15650165 PMCID: PMC544104 DOI: 10.1128/jvi.79.3.1389-1396.2005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Integration into the host cell DNA is an essential part of the retroviral life cycle and is required for the productive replication of a retrovirus. Retroviral integration involves cleavage of the host DNA and insertion of the viral DNA, forming an integration intermediate that contains two gaps, each with a viral 5' flap. The flaps are then removed, and the gap is filled by as yet unidentified nuclease and polymerase activities. It is thought that repair of these gaps flanking the site of retroviral integration is achieved by host DNA repair machinery. The ATM and Rad3-related protein (ATR) is a member of the phosphatidylinositol 3 kinase-related family of protein kinases that play a major role in sensing and triggering repair of DNA lesions in mammalian cells. In an effort to examine the role of ATR in retroviral integration, we used RNA interference to selectively downregulate ATR and measured integration efficiency. In addition, we examined the possible role that Vpr may play in enhancing integration and, in particular, whether activation of ATR by Vpr (Roshal et al., J. Biol. Chem. 278:25879-25886, 2003) will favor human immunodeficiency virus type 1 integration. We conclude that cells in which ATR has been depleted are competent for retroviral integration. We also conclude that the presence of Vpr as a virion-bound protein does not enhance integration of a lentivirus vector in dividing cells.
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Affiliation(s)
- Jason L Dehart
- Division of Cellular Biology and Immunology, Department of Pathology, University of Utah School of Medicine, 30 N 1900 East, SOM 5C210, Salt Lake City, UT 84132, USA
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57
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Ma H, Thibault J, Lu Y, Whiting C, Long S, Lindwall G, Bennett K, Truong L, Aimes RT, Wong-Staal F. The development and applications of nonradioactive plate-formatted DNA-binding assay for Ku70/80, a multifunctional DNA-binding protein complex. Assay Drug Dev Technol 2005; 2:483-95. [PMID: 15671646 DOI: 10.1089/adt.2004.2.483] [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: 11/13/2022] Open
Abstract
Ku is a heterodimer composed of p70 and p80, and is the regulatory subunit of DNA-dependent protein kinase. As a multifunctional DNA-binding protein complex, Ku plays important roles in DNA damage repair through non-homologous end joining and in V(D)J recombination. In addition, Ku has also been implicated in various biological functions including growth control, cell proliferation, cell cycle, chromosome maintenance, transcriptional regulation, apoptosis, and viral infection. In particular, using our Inverse Genomics (Immusol, Inc., San Diego, CA) platform technology, we recently identified Ku80 as an essential co-factor for human immunodeficiency virus replication. Although Ku has been studied extensively in the past years, its in-depth study as well as development as a drug target has been limited by conventional DNA-binding activity assay. Here we describe the development and applications of a nonradioactive DNA binding assay in the 96-well format. We show that this plate-formatted assay is more sensitive and allows for direct quantification when compared with an electrophoretic mobility shift assay. The establishment of this assay will not only facilitate structure and function studies on Ku, but also help the development of Ku protein or its DNA repair enzyme complex as a drug target.
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Affiliation(s)
- Hongwen Ma
- Immusol, Inc., 10790 Roselle Street, San Diego, CA 92121, USA.
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58
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Nielsen AA, Sørensen AB, Schmidt J, Pedersen FS. Analysis of wild-type and mutant SL3-3 murine leukemia virus insertions in the c-myc promoter during lymphomagenesis reveals target site hot spots, virus-dependent patterns, and frequent error-prone gap repair. J Virol 2005; 79:67-78. [PMID: 15596802 PMCID: PMC538719 DOI: 10.1128/jvi.79.1.67-78.2005] [Citation(s) in RCA: 14] [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
The murine leukemia retrovirus SL3-3 induces lymphomas in the T-cell compartment of the hematopoetic system when it is injected into newborn mice of susceptible strains. Previously, our laboratory reported on a deletion mutant of SL3-3 that induces T-cell tumors faster than the wild-type virus (S. Ethelberg, A. B. Sorensen, J. Schmidt, A. Luz, and F. S. Pedersen, J. Virol. 71:9796-9799, 1997). PCR analyses of proviral integrations in the promoter region of the c-myc proto-oncogene in lymphomas induced by wild-type SL3-3 [SL3-3(wt)] and the enhancer deletion mutant displayed a difference in targeting frequency into this locus. We here report on patterns of proviral insertions into the c-myc promoter region from SL3-3(wt), the faster variant, as well as other enhancer variants from a total of approximately 250 tumors. The analysis reveals (i) several integration site hot spots in the c-myc promoter region, (ii) differences in integration patterns between SL3-3(wt) and enhancer deletion mutant viruses, (iii) a correlation between tumor latency and the number of proviral insertions into the c-myc promoter, and (iv) a [5'-(A/C/G)TA(C/G/T)-3'] integration site consensus sequence. Unexpectedly, about 12% of the sequenced insertions were associated with point mutations in the direct repeat flanking the provirus. Based on these results, we propose a model for error-prone gap repair of host-provirus junctions.
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MESH Headings
- Animals
- Animals, Newborn
- Base Sequence
- Consensus Sequence
- DNA Repair
- Enhancer Elements, Genetic
- Female
- Gene Deletion
- Genes, myc
- Leukemia Virus, Murine/genetics
- Leukemia Virus, Murine/pathogenicity
- Leukemia, Experimental/pathology
- Leukemia, Experimental/virology
- Lymphoma, T-Cell/pathology
- Lymphoma, T-Cell/virology
- Male
- Mice
- Molecular Sequence Data
- Mutation
- Promoter Regions, Genetic
- Proto-Oncogene Proteins c-myc/genetics
- Proviruses/genetics
- Retroviridae Infections/pathology
- Retroviridae Infections/virology
- Tumor Virus Infections/pathology
- Tumor Virus Infections/virology
- Virus Integration/genetics
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59
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Lewinski MK, Bushman FD. Retroviral DNA integration--mechanism and consequences. ADVANCES IN GENETICS 2005; 55:147-81. [PMID: 16291214 DOI: 10.1016/s0065-2660(05)55005-3] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Integration of retroviral cDNA into the host cell chromosome is an essential step in its replication. This process is catalyzed by the retroviral integrase protein, which is conserved among retroviruses and retrotransposons. Integrase binds viral and host DNA in a complex, called the preintegration complex (PIC), with other viral and cellular proteins. While the PIC is capable of directing integration of the viral DNA into any chromosomal location, different retroviruses have clear preferences for integration in or near particular chromosomal features. The determinants of integration site selection are under investigation but may include retrovirus-specific interactions between integrase and tethering factors bound to the host cell chromosomes. Research into the mechanisms of retroviral integration site selection has shed light on the phenomena of insertional mutagenesis and viral latency.
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Affiliation(s)
- Mary K Lewinski
- Infectious Disease Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92186, USA
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60
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Waninger S, Kuhen K, Hu X, Chatterton JE, Wong-Staal F, Tang H. Identification of cellular cofactors for human immunodeficiency virus replication via a ribozyme-based genomics approach. J Virol 2004; 78:12829-37. [PMID: 15542635 PMCID: PMC524980 DOI: 10.1128/jvi.78.23.12829-12837.2004] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Ribozymes are small, catalytic RNA molecules that can be engineered to down-regulate gene expression by cleaving specific mRNA. Here we report the selection of hairpin ribozymes that inhibit human immunodeficiency virus (HIV) replication from a combinatorial ribozyme library. We identified a total of 17 effective ribozymes, each capable of inhibiting HIV infection of human CD4(+) cells. These ribozymes target diverse steps of the viral replication cycle, ranging from entry to transcription. One ribozyme suppressed HIV integration and transcription by inhibiting the expression of the Ku80 subunit of the DNA-activated protein kinase. Another ribozyme specifically inhibited long terminal repeat transactivation, while two additional ones blocked a step that can be bypassed by vesicular stomatitis virus G-protein pseudotyping. The function of Ku80 in HIV replication and its mechanism of action were further confirmed using short interfering RNA. Identification of the gene targets of these and other selected ribozymes may reveal novel therapeutic targets for combating HIV infection.
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Affiliation(s)
- Shani Waninger
- Department of Biological Sciences, Biology Unit 1, Florida State University, Tallahassee, FL 32306-4370, USA
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61
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Daniel R, Greger JG, Katz RA, Taganov KD, Wu X, Kappes JC, Skalka AM. Evidence that stable retroviral transduction and cell survival following DNA integration depend on components of the nonhomologous end joining repair pathway. J Virol 2004; 78:8573-81. [PMID: 15280466 PMCID: PMC479090 DOI: 10.1128/jvi.78.16.8573-8581.2004] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
We have previously reported several lines of evidence that support a role for cellular DNA repair systems in completion of the retroviral DNA integration process. Failure to repair an intermediate in the process of integrating viral DNA into host DNA appears to trigger growth arrest or death of a large percentage of infected cells. Cellular proteins involved in the nonhomologous end joining (NHEJ) pathway (DNA-PK(CS)) and the damage-signaling kinases (ATM and ATR) have been implicated in this process. However, some studies have suggested that NHEJ proteins may not be required for the completion of lentiviral DNA integration. Here we provide additional evidence that NHEJ proteins are required for stable transduction by human immunodeficiency type 1 (HIV-1)-based vectors. Our analyses with two different reporters show that the number of stably transduced DNA-PK(CS)-deficient scid fibroblasts was reduced by 80 to 90% compared to the number of control cells. Furthermore, transduction efficiency can be restored to wild-type levels in scid cells that are complemented with a functional DNA-PK(CS) gene. The efficiency of stable transduction by an HIV-1-based vector is also reduced upon infection of Xrcc4 and ligase IV-deficient cells, implying a role for these components of the NHEJ repair pathway. Finally, we show that cells deficient in ligase IV are killed by infection with an integrase-competent but not an integrase-deficient HIV-1 vector. Results presented in this study lend further support to a general role for the NHEJ DNA repair pathway in completion of the retroviral DNA integration process.
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Affiliation(s)
- René Daniel
- Fox Chase Cancer Center, Institute for Cancer Research, 333 Cottman Ave., Philadelphia, PA 19111-2497, USA
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62
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Izsvák Z, Stüwe EE, Fiedler D, Katzer A, Jeggo PA, Ivics Z. Healing the wounds inflicted by sleeping beauty transposition by double-strand break repair in mammalian somatic cells. Mol Cell 2004; 13:279-90. [PMID: 14759372 DOI: 10.1016/s1097-2765(03)00524-0] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2003] [Revised: 11/19/2003] [Accepted: 11/25/2003] [Indexed: 11/17/2022]
Abstract
The Sleeping Beauty (SB) element is a useful tool to probe transposon-host interactions in vertebrates. We investigated requirements of DNA repair factors for SB transposition in mammalian cells. Factors of nonhomologous end joining (NHEJ), including Ku, DNA-PKcs, and Xrcc4 as well as Xrcc3/Rad51C, a complex that functions during homologous recombination, are required for efficient transposition. NHEJ plays a dominant role in repair of transposon excision sites in somatic cells. Artemis is dispensable for transposition, consistent with the lack of a hairpin structure at excision sites. Ku physically interacts with the SB transposase. DNA-PKcs is a limiting factor for transposition and, in addition to repair, has a function in transposition that is independent from its kinase activity. ATM is involved in excision site repair and affects transposition rates. The overlapping but distinct roles of repair factors in transposition and in V(D)J recombination might influence the outcomes of these mechanistically similar processes.
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Affiliation(s)
- Zsuzsanna Izsvák
- Max Delbrück Center for Molecular Medicine, Robert Rössle Str. 10, D-13092 Berlin, Germany
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63
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Abstract
A key early step in the retroviral life cycle is the integration of reverse-transcribed viral cDNA into a chromosome of an infected cell. The key protein player in retroviral integration is the viral integrase, which enters the cell as part of the virus. Although purified integrase protein is necessary and sufficient to perform the basic catalytic DNA breakage and joining steps of retroviral integration, a variety of normal cellular proteins have been implicated as playing important roles in establishing the integrated provirus in cells. This chapter reviews the roles of host cell factors that function during integrase catalysis, during the repair of the resulting DNA recombination intermediate, and by potentially guiding viral preintegration complexes to their chromosomal locations for cDNA integration. The potential to interfere with proper integration by blocking either integrase catalysis or the function of cellular integration cofactors is also discussed.
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Affiliation(s)
- A Engelman
- Department of Cancer Immunology and AIDS, Dana Farber Cancer Institute, 44 Binney Street, Boston, MA 02115, USA.
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64
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Yant SR, Kay MA. Nonhomologous-end-joining factors regulate DNA repair fidelity during Sleeping Beauty element transposition in mammalian cells. Mol Cell Biol 2003; 23:8505-18. [PMID: 14612396 PMCID: PMC262663 DOI: 10.1128/mcb.23.23.8505-8518.2003] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Herein, we report that the DNA-dependent protein kinase (DNA-PK) regulates the DNA damage introduced during Sleeping Beauty (SB) element excision and reinsertion in mammalian cells. Using both plasmid- and chromosome-based mobility assays, we analyzed the repair of transposase-induced double-stranded DNA breaks in cells deficient in either the DNA-binding subunit of DNA-PK (Ku) or its catalytic subunit (DNA-PKcs). We found that the free 3' overhangs left after SB element excision were efficiently and accurately processed by the major Ku-dependent nonhomologous-end-joining pathway. Rejoining of broken DNA molecules in the absence of Ku resulted in extensive end degradation at the donor site and greatly increased the frequency of recombination with ectopic templates. Therefore, the major DNA-PK-dependent DNA damage response predominates over more-error-prone repair pathways and thereby facilitates high-fidelity DNA repair during transposon mobilization in mammalian cells. Although transposable elements were not found to be efficiently circularized after transposase-mediated excision, DNA-PK deficiency supported more-frequent transposase-mediated element insertion than was found in wild-type controls. We conclude that, based on its ability to regulate excision site junctional diversity and transposon insertion frequency, DNA-PK serves an important protective role during transpositional recombination in mammals.
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Affiliation(s)
- Stephen R Yant
- Departments of Pediatrics and Genetics, Stanford University School of Medicine, Stanford, California 94305-5208, USA
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65
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Kilzer JM, Stracker T, Beitzel B, Meek K, Weitzman M, Bushman FD. Roles of host cell factors in circularization of retroviral dna. Virology 2003; 314:460-7. [PMID: 14517098 DOI: 10.1016/s0042-6822(03)00455-0] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Early during retroviral infection, a fraction of the linear reverse-transcribed viral DNA genomes become circularized by cellular enzymes, thereby inactivating the genomes for further replication. Prominent circular DNA forms include 2-long-terminal repeat (LTR) circles, made by DNA end joining, and 1-LTR circles, produced in part by homologous recombination. These reactions provide a convenient paradigm for analyzing the cellular machinery involved in DNA end joining in vertebrate cells. In previous studies, we found that inactivating components of the nonhomologous DNA end-joining (NHEJ) pathway--specifically Ku, ligase 4, or XRCC4--blocked formation of 2-LTR circles. Here we report that inactivating another NHEJ component, the DNA-dependent protein kinase catalytic subunit (DNA-PKcs), had at most modest effects on 2-LTR circle formation, providing informative parallels with other end-joining reactions. We also analyzed cells mutant in components of the RAD50/MRE11/NBS1 nuclease and found a decrease in the relative amount of 1-LTR circles, opposite to the effects of NHEJ mutants. In MRE11-mutant cells, a MRE11 gene mutant in the nuclease catalytic site failed to restore 1-LTR circle formation, supporting a model for the role of MRE11 in 1-LTR circle formation. None of the cellular mutations showed a strong effect on normal integration, consistent with the idea that the cellular pathways leading to circularization are not involved in productive integration.
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Affiliation(s)
- Jennifer M Kilzer
- Infectious Disease Laboratory, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
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66
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Nakai H, Storm TA, Fuess S, Kay MA. Pathways of removal of free DNA vector ends in normal and DNA-PKcs-deficient SCID mouse hepatocytes transduced with rAAV vectors. Hum Gene Ther 2003; 14:871-81. [PMID: 12828858 DOI: 10.1089/104303403765701169] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Elucidation of the mechanisms of transformation of single-stranded (ss) recombinant adeno-associated virus (rAAV) vector genomes into a variety of stable double-stranded (ds) forms is key to a complete understanding of rAAV vector transduction in vivo. Ds monomer genome formation and cellular ds DNA break (DSB) repair pathways that remove free vector ends toxic to cells, presumably play a central role in this process. By delivering rAAV and naked ds linear DNA vectors into livers of DNA-dependent protein kinase catalytic subunit (DNA-PKcs)-deficient severe combined immunodeficiency (SCID) and wild-type mice, we demonstrate the presence of three major pathways for free ds vector end removal: (1) DNA-PKcs-dependent self-circularization, (2) DNA-PKcs-independent self-circularization, and (3) DNA-PKcs-independent concatemerization. By using the DNA-PKcs-independent pathways, mouse hepatocytes efficiently removed free ds rAAV vector ends even in the absence of DNA-PKcs. Our studies suggest a hierarchical organization of these processes; self-circularization is the preferred pathway over concatemerization, although the former has a limited capacity to remove free vector ends. These studies shed new light on the molecular mechanisms of rAAV vector transduction in vivo.
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Affiliation(s)
- Hiroyuki Nakai
- Departments of Pediatrics and Genetics, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305, USA
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67
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Van Maele B, De Rijck J, De Clercq E, Debyser Z. Impact of the central polypurine tract on the kinetics of human immunodeficiency virus type 1 vector transduction. J Virol 2003; 77:4685-94. [PMID: 12663775 PMCID: PMC152151 DOI: 10.1128/jvi.77.8.4685-4694.2003] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2002] [Accepted: 01/16/2003] [Indexed: 11/20/2022] Open
Abstract
Lentiviral vectors derived from human immunodeficiency virus type 1 (HIV-1) show great promise as gene carriers for future gene therapy. Insertion of a fragment containing the central polypurine tract (cPPT) in HIV-1 vector constructs is known to enhance transduction efficiency drastically, reportedly by facilitating the nuclear import of HIV-1 cDNA through a central DNA flap. We have studied the impact of the cPPT on the kinetics of HIV-1 vector transduction by real-time PCR. The kinetics of total HIV-1 DNA, two-long-terminal-repeat (2-LTR) circles, and, by an Alu-PCR, integrated proviral DNA were monitored. About 6 to 12 h after transduction, the total HIV-1 DNA reached a maximum level, followed by a steep decrease. The 2-LTR circles peaked after 24 to 48 h and were diluted upon cell division. Integration of HIV-1 DNA was first detected at 12 h postinfection. When HIV-1 vectors that contained the cPPT were used, DNA synthesis was similar but a threefold higher amount of 2-LTR circles was detected, confirming the impact on nuclear import. Moreover, a 10-fold increase in the amount of integrated DNA was observed in the presence of the cPPT. Only in the absence of the cPPT was a saturation in 2-LTR circle formation seen at a high multiplicity of infection, suggesting a role for the cPPT in overcoming a barrier to the nuclear import of HIV-1 DNA. A major effect of the central DNA flap on the juxtaposition of both LTRs is unlikely, since transduction with HIV-1 vectors containing ectopic cPPT fragments resulted in increased amounts of 2-LTR circles as well as integrated DNA. Inhibitors of transduction by cPPT-containing HIV vectors were also studied by real-time PCR. The reverse transcriptase inhibitor azidothymidine (AZT) and the nonnucleoside reverse transcriptase inhibitor alpha-APA clearly inhibited viral DNA synthesis, whereas integrase inhibitors such as the diketo acid L-708,906 and the pyranodipyrimidine V-165 specifically inhibited integration.
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68
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Siva AC, Bushman F. Poly(ADP-ribose) polymerase 1 is not strictly required for infection of murine cells by retroviruses. J Virol 2002; 76:11904-10. [PMID: 12414932 PMCID: PMC136881 DOI: 10.1128/jvi.76.23.11904-11910.2002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The DNA-breaking and -joining steps initiating retroviral integration are well understood, but the later steps, thought to be carried out by cellular DNA repair enzymes, have not been fully characterized. Poly(ADP-ribose) polymerase 1 (PARP-1) has been proposed to play a role late during retroviral integration, because infection by human immunodeficiency virus (HIV)-based vectors was reported to be strongly inhibited in PARP-1-deficient fibroblasts. PARP-1, a nuclear enzyme, binds tightly to nicked DNA and synthesizes poly(ADP-ribose) as an early response to DNA damage. To investigate the role of PARP-1 in retroviral integration, we infected wild-type and PARP-1-deficient mouse embryonic fibroblasts (MEFs) separately with two HIV type 1-derived, vesicular stomatitis virus G-pseudotyped lentivirus vectors. Surprisingly, infection of both wild-type and PARP-1-deficient cells was observed with both vectors. Marker gene transduction and provirus formation by one vector was reduced by 45 to 75% compared to the wild type, but the other vector was unaffected by the PARP-1 mutant. In addition, PARP-1-deficient MEFs infected with Moloney murine leukemia virus showed no decrease in virus output after infection compared to the wild type. We conclude that PARP-1 cannot be strictly required for retroviral infection because replication steps, including integration, can proceed efficiently in its absence.
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Affiliation(s)
- Amara C Siva
- Infectious Disease Laboratory, The Salk Institute, La Jolla, California 92037, USA
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69
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Pluymers W, Pais G, Van Maele B, Pannecouque C, Fikkert V, Burke, Jr. TR, De Clercq E, Witvrouw M, Neamati N, Debyser Z. Inhibition of human immunodeficiency virus type 1 integration by diketo derivatives. Antimicrob Agents Chemother 2002; 46:3292-7. [PMID: 12234864 PMCID: PMC128766 DOI: 10.1128/aac.46.10.3292-3297.2002] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A series of diketo derivatives was found to inhibit human immunodeficiency virus type 1 (HIV-1) integrase activity. Only L-708,906 inhibited the replication of HIV-1(III(B)) (50% effective concentration, 12 micro M), HIV-1 clinical strains, HIV-1 strains resistant to reverse transcriptase or fusion inhibitors, HIV-2 (ROD strain) and simian immunodeficiency virus (MAC(251)). The combinations of L-708,906 with zidovudine, nevirapine, or nelfinavir proved to be subsynergistic. In cell culture, addition of L-708,906 could be postponed for 7 h after infection, a moment coinciding with HIV integration. Inhibition of integration in cell culture was confirmed by quantitative Alu-PCR.
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Affiliation(s)
- Wim Pluymers
- Rega Institute for Medical Research, K.U. Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium, Laboratory of Medicinal Chemistry, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, School of Pharmacy, University of Southern California, Los Angeles, California 90089
| | - Godwin Pais
- Rega Institute for Medical Research, K.U. Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium, Laboratory of Medicinal Chemistry, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, School of Pharmacy, University of Southern California, Los Angeles, California 90089
| | - Bénédicte Van Maele
- Rega Institute for Medical Research, K.U. Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium, Laboratory of Medicinal Chemistry, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, School of Pharmacy, University of Southern California, Los Angeles, California 90089
| | - Christophe Pannecouque
- Rega Institute for Medical Research, K.U. Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium, Laboratory of Medicinal Chemistry, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, School of Pharmacy, University of Southern California, Los Angeles, California 90089
| | - Valery Fikkert
- Rega Institute for Medical Research, K.U. Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium, Laboratory of Medicinal Chemistry, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, School of Pharmacy, University of Southern California, Los Angeles, California 90089
| | - Terrence R. Burke, Jr.
- Rega Institute for Medical Research, K.U. Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium, Laboratory of Medicinal Chemistry, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, School of Pharmacy, University of Southern California, Los Angeles, California 90089
| | - Erik De Clercq
- Rega Institute for Medical Research, K.U. Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium, Laboratory of Medicinal Chemistry, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, School of Pharmacy, University of Southern California, Los Angeles, California 90089
| | - Myriam Witvrouw
- Rega Institute for Medical Research, K.U. Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium, Laboratory of Medicinal Chemistry, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, School of Pharmacy, University of Southern California, Los Angeles, California 90089
| | - Nouri Neamati
- Rega Institute for Medical Research, K.U. Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium, Laboratory of Medicinal Chemistry, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, School of Pharmacy, University of Southern California, Los Angeles, California 90089
| | - Zeger Debyser
- Rega Institute for Medical Research, K.U. Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium, Laboratory of Medicinal Chemistry, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, School of Pharmacy, University of Southern California, Los Angeles, California 90089
- Corresponding author. Mailing address: Rega Institute for Medical Research, K.U. Leuven, Minderbroederstraat 10, B-3000 Leuven, Belgium. Phone: 32 16 33 21 83. Fax: 32 16 33 21 31. E-mail:
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70
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Jeanson L, Subra F, Vaganay S, Hervy M, Marangoni E, Bourhis J, Mouscadet JF. Effect of Ku80 depletion on the preintegrative steps of HIV-1 replication in human cells. Virology 2002; 300:100-8. [PMID: 12202210 DOI: 10.1006/viro.2002.1515] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
To gain new insights regarding the role of Ku, the DNA-PK DNA-binding component, during lentiviral DNA integration, we have investigated the HIV-1 replication in Ku80-depleted human cells. CEM4fx cells underexpressing the Ku80 factor were selected after transduction by a retroviral vector expressing the Ku80 full-length antisense sequence. De novo infection experiment with NL4.3 HIV-1 strain led to the observation that the viral replication was delayed in the Ku80-depleted cells. Early events of the replicative cycle, including nuclear import of the viral DNA, were not affected. In contrast, the formation of the 2-LTR circles was impaired, thus demonstrating the implication of Ku in HIV-1 DNA circularization, for the first time in human cells. Furthermore, the detection of integrated proviruses by an Alu-LTR-nested PCR amplification method was affected in cells underexpressing Ku80. These results suggest that this factor may also be involved in the mechanisms leading to the stable establishment of HIV-1 provirus.
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Affiliation(s)
- Laurence Jeanson
- UMR8532 CNRS, Institut Gustave Roussy, PR2, 39 rue Camille Desmoulins, 94805, Villejuif, France
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71
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Baekelandt V, Claeys A, Eggermont K, Lauwers E, De Strooper B, Nuttin B, Debyser Z. Characterization of lentiviral vector-mediated gene transfer in adult mouse brain. Hum Gene Ther 2002; 13:841-53. [PMID: 11975850 DOI: 10.1089/10430340252899019] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Lentiviral vectors are promising tools for gene transfer into the central nervous system. We have characterized in detail transduction with human immunodeficiency virus type 1 (HIV-1)-derived vectors encoding enhanced green fluorescent protein (eGFP) in the adult mouse brain. Different brain regions such as the striatum, hippocampus, and the lateral ventricle were targeted. The eGFP protein was transported anterogradely in the nigrostriatal pathway, but we have found no evidence of transport of the lentiviral vector particle. The performance levels of the different generations of packaging and transfer plasmid were compared. Omission of the accessory genes from the packaging plasmid resulted in a modest decrease in transgene expression. Inclusion of the woodchuck hepatitis posttranscriptional regulatory element, on the one hand, and the central polypurine tract and termination sequences, on the other hand, in the transfer vector each resulted in a 4- to 5-fold increase in transgene expression levels. Combination of both elements enhanced expression levels more than the sum of the individual components, suggesting a synergistic effect. In the serum of mice injected with lentiviral vectors a humoral response to vector proteins was detected, but this did not compromise transgene expression. Immune response to the transgene was found only in a minority of the animals.
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Affiliation(s)
- Veerle Baekelandt
- Gene Therapy Program, Laboratory for Experimental Neurosurgery and Neuroanatomy, Katholieke Universiteit Leuven, Provisorium 1, Minderbroedersstraat 17, B-3000 Leuven, Belgium.
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72
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Jeanson L, Mouscadet JF. Ku represses the HIV-1 transcription: identification of a putative Ku binding site homologous to the mouse mammary tumor virus NRE1 sequence in the HIV-1 long terminal repeat. J Biol Chem 2002; 277:4918-24. [PMID: 11733502 DOI: 10.1074/jbc.m110830200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ku has been implicated in nuclear processes, including DNA break repair, transcription, V(D)J recombination, and telomere maintenance. Its mode of action involves two distinct mechanisms: one in which a nonspecific binding occurs to DNA ends and a second that involves a specific binding to negative regulatory elements involved in transcription repression. Such elements were identified in mouse mammary tumor virus and human T cell leukemia virus retroviruses. The purpose of this study was to investigate a role for Ku in the regulation of human immunodeficiency virus (HIV)-1 transcription. First, HIV-1 LTR activity was studied in CHO-K1 cells and in CH0-derived xrs-6 cells, which are devoid of Ku80. LTR-driven expression of a reporter gene was significantly increased in xrs-6 cells. This enhancement was suppressed after re-expression of Ku80. Second, transcription of HIV-1 was followed in U1 human cells that were depleted in Ku by using a Ku80 antisense RNA. Ku depletion led to a increase of both HIV-1 mRNA synthesis and viral production compared with the parent cells. These results demonstrate that Ku acts as a transcriptional repressor of HIV-1 expression. Finally, a putative Ku-specific binding site was identified within the negative regulatory region of the HIV-1 long terminal repeat, which may account for this repression of transcription.
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Affiliation(s)
- Laurence Jeanson
- CNRS UMR8532, Institut Gustave-Roussy, PR2, 39 rue Camille Desmoulins, 94805 Villejuif, France
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73
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Debyser Z, Cherepanov P, Van Maele B, De Clercq E, Witvrouw M. In search of authentic inhibitors of HIV-1 integration. Antivir Chem Chemother 2002; 13:1-15. [PMID: 12180645 DOI: 10.1177/095632020201300101] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Current strategies for the treatment of HIV infection are based on cocktails of drugs that target the viral reverse transcriptase or protease enzymes. At present, the clinical benefit of this combination therapy for HIV-infected patients is considerable, although it is not clear how long this effect will last taking into account the emergence of multiple drug-resistant viral strains. Addition of new anti-HIV drugs targeting additional steps of the viral replication cycle may increase the potency of inhibition and prevent resistance development. During HIV replication, integration of the viral genome into the cellular chromosome is an essential step catalysed by the viral integrase. Although HIV integrase is an attractive target for antiviral therapy, so far all research efforts have led to the identification of only one series of compounds that selectively inhibit the integration step during HIV replication, namely the diketo acids. In this review we try to address the question why it has proven so difficult to find potent and selective integrase inhibitors. We point to potential pitfalls in defining an inhibitor as an authentic integrase inhibitor, and propose new strategies and technologies for the discovery of authentic HIV integration inhibitors.
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Affiliation(s)
- Zeger Debyser
- Rega Institute for Medical Research, KU Leuven, Flanders, Belgium.
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74
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Abstract
Ku proteins are associated with a variety of cellular processes such as repair of DNA-double-strand breaks, telomere maintenance and retrotransposition. In recent years, we have learned a lot about their cellular and molecular functions and it has turned out that Ku-dependent processes affect the stability of the genome, both positively and negatively, in several ways. This article gives an overview on the role of Ku in determining the shape of the genome.
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Affiliation(s)
- Anna A. Friedl
- Strahlenbiologisches Institut der Universität München, Schiller Straße 42, 80336 München, Germany
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75
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Li L, Olvera JM, Yoder KE, Mitchell RS, Butler SL, Lieber M, Martin SL, Bushman FD. Role of the non-homologous DNA end joining pathway in the early steps of retroviral infection. EMBO J 2001; 20:3272-81. [PMID: 11406603 PMCID: PMC150207 DOI: 10.1093/emboj/20.12.3272] [Citation(s) in RCA: 275] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Early after infection, the retroviral RNA genome is reverse transcribed to generate a linear cDNA copy, then that copy is integrated into a chromosome of the host cell. We report that unintegrated viral cDNA is a substrate for the host cell non-homologous DNA end joining (NHEJ) pathway, which normally repairs cellular double-strand breaks by end ligation. NHEJ activity was found to be required for an end-ligation reaction that circularizes a portion of the unintegrated viral cDNA in infected cells. Consistent with this, the NHEJ proteins Ku70 and Ku80 were found to be bound to purified retroviral replication intermediates. Cells defective in NHEJ are known to undergo apoptosis in response to retroviral infection, a response that we show requires reverse transcription to form the cDNA genome but not subsequent integration. We propose that the double-strand ends present in unintegrated cDNA promote apoptosis, as is known to be the case for chromosomal double-strand breaks, and cDNA circularization removes the pro-apoptotic signal.
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Affiliation(s)
| | | | | | | | | | - Michael Lieber
- Infectious Disease Laboratory, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037,
Department of Pathology, Norris Cancer Center, University of Southern California, Los Angeles, CA and University of Colorado School of Medicine, 4200 E. Ninth Avenue, Denver, CO, USA Corresponding author e-mail:
| | - Sandra L. Martin
- Infectious Disease Laboratory, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037,
Department of Pathology, Norris Cancer Center, University of Southern California, Los Angeles, CA and University of Colorado School of Medicine, 4200 E. Ninth Avenue, Denver, CO, USA Corresponding author e-mail:
| | - Frederic D. Bushman
- Infectious Disease Laboratory, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037,
Department of Pathology, Norris Cancer Center, University of Southern California, Los Angeles, CA and University of Colorado School of Medicine, 4200 E. Ninth Avenue, Denver, CO, USA Corresponding author e-mail:
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76
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Ha HC, Juluri K, Zhou Y, Leung S, Hermankova M, Snyder SH. Poly(ADP-ribose) polymerase-1 is required for efficient HIV-1 integration. Proc Natl Acad Sci U S A 2001; 98:3364-8. [PMID: 11248084 PMCID: PMC30659 DOI: 10.1073/pnas.051633498] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Poly(ADP-ribose) polymerase-1 (PARP-1; EC ) is an abundant nuclear enzyme, activated by DNA strand breaks to attach up to 200 ADP-ribose groups to nuclear proteins. As retroviral infection requires integrase-catalyzed DNA strand breaks, we examined infection of pseudotyped HIV type I in fibroblasts from mice with a targeted deletion of PARP-1. Viral infection is almost totally abolished in PARP-1 knockout fibroblasts. This protection from infection reflects prevention of viral integration into the host genome. These findings suggest a potential for PARP inhibitors in therapy of HIV type I infection.
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Affiliation(s)
- H C Ha
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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