51
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Kühne C, Tjörnhammar ML, Pongor S, Banks L, Simoncsits A. Repair of a minimal DNA double-strand break by NHEJ requires DNA-PKcs and is controlled by the ATM/ATR checkpoint. Nucleic Acids Res 2004; 31:7227-37. [PMID: 14654698 PMCID: PMC291875 DOI: 10.1093/nar/gkg937] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Mammalian cells primarily rejoin DNA double-strand breaks (DSBs) by the non-homologous end-joining (NHEJ) pathway. The joining of the broken DNA ends appears directly without template and accuracy is ensured by the NHEJ factors that are under ATM/ATR regulated checkpoint control. In the current study we report the engineering of a mono-specific DNA damaging agent. This was used to study the molecular requirements for the repair of the least complex DSB in vivo. Single-chain PvuII restriction enzymes fused to protein delivery sequences transduce cells efficiently and induce blunt end DSBs in vivo. We demonstrate that beside XRCC4/LigaseIV and KU, the DNA-PK catalytic subunit (DNA-PKcs) is also essential for the joining of this low complex DSB in vivo. The appearance of blunt end 3'-hydroxyl and 5'-phosphate DNA DSBs induces a significantly higher frequency of anaphase bridges in cells that do not contain functional DNA-PKcs, suggesting an absolute requirement for DNA-PKcs in the control of chromosomal stability during end joining. Moreover, these minimal blunt end DSBs are sufficient to induce a p53 and ATM/ATR checkpoint function.
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Affiliation(s)
- Christian Kühne
- International Center for Genetic Engineering and Biotechnology (ICGEB), Area Science Park, Padriciano 99, I-34000 Trieste, Italy.
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52
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Modesti M, Junop MS, Ghirlando R, van de Rakt M, Gellert M, Yang W, Kanaar R. Tetramerization and DNA ligase IV interaction of the DNA double-strand break repair protein XRCC4 are mutually exclusive. J Mol Biol 2003; 334:215-28. [PMID: 14607114 DOI: 10.1016/j.jmb.2003.09.031] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The XRCC4 protein is of critical importance for the repair of broken chromosomal DNA by non-homologous end joining (NHEJ). The absence of XRCC4 abolishes chromosomal NHEJ almost completely. One reason for this severe phenotype is that XRCC4 binds and modulates the stability and activity of the NHEJ-specific ligase, DNA ligase IV. XRCC4 in solution is in equilibrium between the dimeric and tetrameric forms. Previous structural studies have shown that the interface between dimers is located in the same region as that implicated in DNA ligase IV interaction. With the use of equilibrium sedimentation analysis, we show here that only the XRCC4 dimer can associate with DNA ligase IV, forming a monodisperse complex of 2:1 stoichiometry in solution. In addition, physical analysis of XRCC4/DNA ligase IV complex formation, combined with mutational analysis of XRCC4, indicates that tetramerization and DNA ligase IV binding are mutually exclusive. We propose that the putative function of the XRCC4 tetramer is distinct from its DNA ligase IV-associated function.
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Affiliation(s)
- Mauro Modesti
- Department of Cell Biology and Genetics, Erasmus Medical Center, P.O. Box 1738, 3000 DR, Rotterdam, The Netherlands
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53
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Jones JM, Gellert M. Autoubiquitylation of the V(D)J recombinase protein RAG1. Proc Natl Acad Sci U S A 2003; 100:15446-51. [PMID: 14671314 PMCID: PMC307587 DOI: 10.1073/pnas.2637012100] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
V(D)J recombination, the rearrangement of gene segments to assemble Ig and T cell receptor coding regions, is vital to B and T lymphocyte development. Here, we demonstrate that the V(D)J recombinase protein RAG1 undergoes ubiquitylation in cells. In vitro, the RING finger domain of RAG1 acts as a ubiquitin ligase that mediates its own ubiquitylation at a highly conserved K residue in the RAG1 amino-terminal region. Ubiquitylation is best supported by a specific ubiquitin-conjugating enzyme, UbcH3/CDC34, and requires an intact RAG1 RING finger motif. Disruption of the RING finger and certain RAG1 N-terminal truncations are associated with immunodeficiency in human patients, suggesting that RAG1's ubiquitin ligase is required for its biological role in lymphocyte development.
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Affiliation(s)
- Jessica M Jones
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Building 5/Room 241, Bethesda, MD 20892, USA
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54
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Jiang H, Ross AE, Desiderio S. Cell cycle-dependent accumulation in vivo of transposition-competent complexes between recombination signal ends and full-length RAG proteins. J Biol Chem 2003; 279:8478-86. [PMID: 14660558 DOI: 10.1074/jbc.m311219200] [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: 11/06/2022] Open
Abstract
V(D)J recombination is initiated by a specialized transposase consisting of RAG-1 and RAG-2. Because full-length RAG proteins are insoluble under physiologic conditions, most previous analyses of RAG activity in vitro have used truncated core RAG-1 and RAG-2 fragments. These studies identified an intermediate in V(D)J recombination, the signal end complex (SEC), in which core RAG proteins remain associated with recombination signal sequences at the cleaved signal ends. From transfected cells expressing affinity-tagged RAG proteins, we have isolated in vivo assembled SECs containing full-length RAG proteins and cleaved recombination substrates. SEC formation in vivo did not require the repair proteins DNA-dependent protein kinase, Ku80, or XRCC4. In the presence of full-length RAG-2, SEC formation in vivo was cell cycle-regulated and restricted to the G(0)/G(1) phases. In contrast, complexes accumulated throughout cell cycle in cells expressing a RAG-2 CDK2 phosphorylation site mutant. Both core and full-length SECs supported transposition in vitro with similar efficiencies. Intracellular SECs, which are likely to persist in the absence of coding ends, represent potential donors whose transposition is not suppressed by the non-core regions of the RAG proteins.
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Affiliation(s)
- Hao Jiang
- Department of Molecular Biology and Genetics, Program in Immunology, Institute for Cell Engineering, and Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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55
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Clatworthy AE, Valencia MA, Haber JE, Oettinger MA. V(D)J recombination and RAG-mediated transposition in yeast. Mol Cell 2003; 12:489-99. [PMID: 14536087 DOI: 10.1016/s1097-2765(03)00305-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Antigen receptor genes are assembled during lymphoid development by a specialized recombination reaction normally observed only in cells of the vertebrate immune system. Here, we show that expression in Saccharomyces cerevisiae of murine RAG1 and RAG2, the lymphoid-specific components of the V(D)J recombinase, is sufficient to induce V(D)J cleavage and rejoining in this lower eukaryote. The RAG proteins cleave recombination substrates introduced into yeast cells, generating signal ends that can be joined to form signal joints. These signal joints are precise, as in mammalian cells, and their formation is dependent on a yeast nonhomologous end-joining protein, the XRCC4 homolog LIF1. Moreover, joining of SmaI-generated blunt ends is generally imprecise in the yeast strain used here, suggesting that the RAG proteins influence signal-end joining. Cleaved signal ends are also transposed into new sites in DNA, allowing RAG-induced transposition to be studied in vivo.
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Affiliation(s)
- Anne E Clatworthy
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
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56
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Abstract
Chromosome breakage--a dangerous event that has triggered the evolution of several double-strand break repair pathways--has been co-opted by the immune system as an integral part of B- and T-cell development. This is a daring strategy, as improper repair can be deadly for the cell, if not for the whole organism. Even more daring, however, is the choice of a promiscuous transposase as the nuclease responsible for chromosome breakage, as the possibility of transposition brings an entirely new set of risks. What mechanisms constrain the dangerous potential of the recombinase and preserve genomic integrity during immune-system development?
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Affiliation(s)
- David B Roth
- Department of Pathology, Program in Molecular Pathogenesis, Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York 10016, USA.
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57
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Elkin SK, Matthews AG, Oettinger MA. The C-terminal portion of RAG2 protects against transposition in vitro. EMBO J 2003; 22:1931-8. [PMID: 12682025 PMCID: PMC154476 DOI: 10.1093/emboj/cdg184] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The assembly of antigen receptor genes by V(D)J recombination is initiated by the RAG1/RAG2 protein complex, which introduces double-strand breaks between recombination signal sequences and their coding DNA. Truncated forms of RAG1 and RAG2 are functional in vivo and have been used to study V(D)J cleavage, hybrid joint formation and transposition in vitro. Here we have characterized the activities of the full-length proteins. Unlike core RAG2, which supports robust transposition in vitro, full-length RAG2 blocks transposition of signal ends following V(D)J cleavage. Thus, one role of this non-catalytic domain may be to prevent transposition in developing lymphoid cells. Although full-length RAG1 and RAG2 proteins rarely form hybrid joints in vivo in the absence of non-homologous end-joining factors, we show that the full-length proteins alone can catalyze this reaction in vitro.
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Affiliation(s)
- Sheryl K Elkin
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
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58
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Messier TL, O’Neill J, Hou SM, Nicklas JA, Finette BA. In vivo transposition mediated by V(D)J recombinase in human T lymphocytes. EMBO J 2003; 22:1381-8. [PMID: 12628930 PMCID: PMC151080 DOI: 10.1093/emboj/cdg137] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The rearrangement of immunoglobulin (Ig) and T-cell receptor (TCR) genes in lymphocytes by V(D)J recombinase is essential for immunological diversity in humans. These DNA rearrangements involve cleavage by the RAG1 and RAG2 (RAG1/2) recombinase enzymes at recombination signal sequences (RSS). This reaction generates two products, cleaved signal ends and coding ends. Coding ends are ligated by non-homologous end-joining proteins to form a functional Ig or TCR gene product, while the signal ends form a signal joint. In vitro studies have demonstrated that RAG1/2 are capable of mediating the transposition of cleaved signal ends into non-specific sites of a target DNA molecule. However, to date, in vivo transposition of signal ends has not been demonstrated. We present evidence of in vivo inter-chromosomal transposition in humans mediated by V(D)J recombinase. T-cell isolates were shown to contain TCRalpha signal ends from chromosome 14 inserted into the X-linked hypo xanthine-guanine phosphoribosyl transferase locus, resulting in gene inactivation. These findings implicate V(D)J recombinase-mediated transposition as a mutagenic mechanism capable of deleterious genetic rearrangements in humans.
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MESH Headings
- Base Sequence
- Binding Sites
- Chromosomes, Human, Pair 14
- Chromosomes, Human, X
- Clone Cells
- DNA Nucleotidyltransferases/metabolism
- Gene Rearrangement, T-Lymphocyte
- Gene Silencing
- Genes, Immunoglobulin
- Genes, T-Cell Receptor alpha
- Homeodomain Proteins/metabolism
- Humans
- Hypoxanthine Phosphoribosyltransferase/genetics
- Immunoglobulin Joining Region/genetics
- Immunoglobulin Joining Region/immunology
- Models, Genetic
- Molecular Sequence Data
- Receptors, Antigen, T-Cell
- Recombination, Genetic
- T-Lymphocytes/enzymology
- T-Lymphocytes/immunology
- VDJ Recombinases
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Affiliation(s)
- Terri L. Messier
- Department of Pediatrics, Vermont Cancer Center, Genetics Laboratory and Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA and Department of Bioscience, Karolinska Institute, Huddinge, Sweden 141 57 Corresponding author e-mail:
| | - J.Patrick O’Neill
- Department of Pediatrics, Vermont Cancer Center, Genetics Laboratory and Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA and Department of Bioscience, Karolinska Institute, Huddinge, Sweden 141 57 Corresponding author e-mail:
| | - Sai-Mei Hou
- Department of Pediatrics, Vermont Cancer Center, Genetics Laboratory and Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA and Department of Bioscience, Karolinska Institute, Huddinge, Sweden 141 57 Corresponding author e-mail:
| | - Janice A. Nicklas
- Department of Pediatrics, Vermont Cancer Center, Genetics Laboratory and Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA and Department of Bioscience, Karolinska Institute, Huddinge, Sweden 141 57 Corresponding author e-mail:
| | - Barry A. Finette
- Department of Pediatrics, Vermont Cancer Center, Genetics Laboratory and Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA and Department of Bioscience, Karolinska Institute, Huddinge, Sweden 141 57 Corresponding author e-mail:
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59
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de Villartay JP. V(D)J recombination and DNA repair: lessons from human immune deficiencies and other animal models. Curr Opin Allergy Clin Immunol 2002; 2:473-9. [PMID: 14752329 DOI: 10.1097/00130832-200212000-00001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW V(D)J recombination not only represents the main mechanism for the diversification of the immune system, it also constitutes a critical checkpoint in the development of both B and T lymphocytes. While a defect in V(D)J recombination leads to severe combined immune deficiency, a deregulation of this process can participate in the onset of lymphoid malignancies. RECENT FINDINGS The careful analysis of human severe combined immune deficiency patients as well as engineered murine models provided several new interesting insights into the physiopathology of the V(D)J recombination process. A new factor of the V(D)J recombination/DNA repair machinery, Artemis, was identified based on its deficiency in human severe combined immune deficiency patients. It also became evident from knockout mouse studies that DNA repair factors that participate in V(D)J recombination can be considered as genomic caretakers. SUMMARY While V(D)J recombination was first recognized as a critical checkpoint in the development of the immune system, the discovery of several DNA repair factors that participate in this reaction shed light on more general aspects of genomic stability and cancer predisposition.
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Affiliation(s)
- Jean-Pierre de Villartay
- Developpement Normal et Pathologie du système Immunataire, INSERM U429, Hôpital Necker Enfants-Malades, Paris, France.
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60
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Cherepanov AV, de Vries S. Dynamic mechanism of nick recognition by DNA ligase. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:5993-9. [PMID: 12473094 DOI: 10.1046/j.1432-1033.2002.03309.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
DNA ligases are the enzymes responsible for the repair of single-stranded and double-stranded nicks in dsDNA. DNA ligases are structurally similar, possibly sharing a common molecular mechanism of nick recognition and ligation catalysis. This mechanism remains unclear, in part because the structure of ligase in complex with dsDNA has yet to be solved. DNA ligases share common structural elements with DNA polymerases, which have been cocrystallized with dsDNA. Based on the observed DNA polymerase-dsDNA interactions, we propose a mechanism for recognition of a single-stranded nick by DNA ligase. According to this mechanism, ligase induces a B-to-A DNA helix transition of the enzyme-bound dsDNA motif, which results in DNA contraction, bending and unwinding. For non-nicked dsDNA, this transition is reversible, leading to dissociation of the enzyme. For a nicked dsDNA substrate, the contraction of the enzyme-bound DNA motif (a) triggers an opened-closed conformational change of the enzyme, and (b) forces the motif to accommodate the strained A/B-form hybrid conformation, in which the nicked strand tends to retain a B-type helix, while the non-nicked strand tends to form a shortened A-type helix. We propose that this conformation is the catalytically competent transition state, which leads to the formation of the DNA-AMP intermediate and to the subsequent sealing of the nick.
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Affiliation(s)
- Alexei V Cherepanov
- Kluyver Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
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61
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Swanson PC. A RAG-1/RAG-2 tetramer supports 12/23-regulated synapsis, cleavage, and transposition of V(D)J recombination signals. Mol Cell Biol 2002; 22:7790-801. [PMID: 12391148 PMCID: PMC134746 DOI: 10.1128/mcb.22.22.7790-7801.2002] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Initiation of V(D)J recombination involves the synapsis and cleavage of a 12/23 pair of recombination signal sequences by RAG-1 and RAG-2. Ubiquitous nonspecific DNA-bending factors of the HMG box family, such as HMG-1, are known to assist in these processes. After cleavage, the RAG proteins remain bound to the cut signal ends and, at least in vitro, support the integration of these ends into unrelated target DNA via a transposition-like mechanism. To investigate whether the protein complex supporting synapsis, cleavage, and transposition of V(D)J recombination signals utilized the same complement of RAG and HMG proteins, I compared the RAG protein stoichiometries and activities of discrete protein-DNA complexes assembled on intact, prenicked, or precleaved recombination signal sequence (RSS) substrates in the absence and presence of HMG-1. In the absence of HMG-1, I found that two discrete RAG-1/RAG-2 complexes are detected by mobility shift assay on all RSS substrates tested. Both contain dimeric RAG-1 and either one or two RAG-2 subunits. The addition of HMG-1 supershifts both complexes without altering the RAG protein stoichiometry. I find that 12/23-regulated recombination signal synapsis and cleavage are only supported in a protein-DNA complex containing HMG-1 and a RAG-1/RAG-2 tetramer. Interestingly, the RAG-1/RAG-2 tetramer also supports transposition, but HMG-1 is dispensable for its activity.
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Affiliation(s)
- Patrick C Swanson
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, Nebraska 68178, USA.
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62
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Nagawa F, Kodama M, Nishihara T, Ishiguro KI, Sakano H. Footprint analysis of recombination signal sequences in the 12/23 synaptic complex of V(D)J recombination. Mol Cell Biol 2002; 22:7217-25. [PMID: 12242298 PMCID: PMC139802 DOI: 10.1128/mcb.22.20.7217-7225.2002] [Citation(s) in RCA: 15] [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
In V(D)J joining of antigen receptor genes, two recombination signal sequences (RSSs), 12-RSS and 23-RSS, are paired and complexed with the protein products of recombination-activating genes RAG1 and RAG2. Using magnetic beads, we purified the pre- and postcleavage complexes of V(D)J joining and analyzed them by DNase I footprinting. In the precleavage synaptic complex, strong protection was seen not only in the 9-mer and spacer regions but also near the coding border of the 7-mer. This is a sharp contrast to the single RSS-RAG complex where the 9-mer plays a major role in the interaction. We also analyzed the postcleavage signal end complex by footprinting. Unlike what was seen with the precleavage complex, the entire 7-mer and its neighboring spacer regions were protected. The present study indicates that the RAG-RSS interaction in the 7-mer region drastically changes once the synaptic complex is formed for cleavage.
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Affiliation(s)
- Fumikiyo Nagawa
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
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63
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Jones JM, Gellert M. Ordered assembly of the V(D)J synaptic complex ensures accurate recombination. EMBO J 2002; 21:4162-71. [PMID: 12145216 PMCID: PMC126141 DOI: 10.1093/emboj/cdf394] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recombination of gene segments at the immunoglobulin and T-cell receptor loci requires that the RAG1 and RAG2 proteins bring together DNA signal sequences (RSSs) with 12- and 23-bp spacers into a synaptic complex and cleave the DNA. A RAG1/2 multimer that can cleave both signals is shown to assemble on an isolated RSS, and the complementary RSS enters this complex as naked DNA. When RAG1/2 is allowed to bind 12 and 23 RSSs separately prior to their mixing, synaptic complex assembly and cleavage activity are greatly reduced, indicating that only a complex initially assembled on a single RSS leads to productive cleavage. RAG1/2 complexes assembled on 12 RSSs will only incorporate 23 partners, while complexes assembled on 23 RSSs show a 5- to 6-fold preference for 12 partners. Thus, initial assembly on a 12 RSS most accurately reflects the strict 12/23 coupled cleavage observed in the cell. Additional cellular factors such as chromatin may ensure that RAG1/2 first assembles on a 12 RSS, and then a free 23 RSS enters to activate cleavage.
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Affiliation(s)
- Jessica M Jones
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Building 5/Room 241, Bethesda, MD 20892, USA
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64
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Abstract
The RAG proteins were long thought to serve merely as a nuclease, initiating recombination by cleaving DNA. Recent work has shown, however, that these proteins are essential for many steps in the recombination pathway, such as opening hairpins and joining broken DNA ends, and that they can also act as a transposase, targeting distorted DNA structures such as hairpins.
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Affiliation(s)
- Vicky L Brandt
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.
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65
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Melek M, Jones JM, O'Dea MH, Pais G, Burke TR, Pommier Y, Neamati N, Gellert M. Effect of HIV integrase inhibitors on the RAG1/2 recombinase. Proc Natl Acad Sci U S A 2002; 99:134-7. [PMID: 11756686 PMCID: PMC117527 DOI: 10.1073/pnas.012610699] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Assembly of functional Ig and T cell receptor genes by V(D)J recombination depends on site-specific cleavage of chromosomal DNA by the RAG1/2 recombinase. As RAG1/2 action has mechanistic similarities to DNA transposases and integrases such as HIV-1 integrase, we sought to determine how integrase inhibitors of the diketo acid type would affect the various activities of RAG1/2. Both of the inhibitors we tested interfered with DNA cleavage and disintegration activities of RAG1/2, apparently by disrupting interaction with the DNA motifs bound specifically by the recombinase. The inhibitors did not ablate RAG1/2's transposition activity or capture of nonspecific transpositional target DNA, suggesting this DNA occupies a site on the recombinase different from that used for specific binding. These results further underscore the similarities between RAG1/2 and integrase and suggest that certain integrase inhibitors may have the potential to interfere with aspects of B and T cell development.
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Affiliation(s)
- Meni Melek
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Building 5, Room 241, Bethesda, MD 20892, USA
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