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Yeap LS, Meng FL. Cis- and trans-factors affecting AID targeting and mutagenic outcomes in antibody diversification. Adv Immunol 2019; 141:51-103. [PMID: 30904133 DOI: 10.1016/bs.ai.2019.01.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Antigen receptor diversification is a hallmark of adaptive immunity which allows specificity of the receptor to particular antigen. B cell receptor (BCR) or its secreted form, antibody, is diversified through antigen-independent and antigen-dependent mechanisms. During B cell development in bone marrow, BCR is diversified via V(D)J recombination mediated by RAG endonuclease. Upon stimulation by antigen, B cell undergo somatic hypermutation (SHM) to allow affinity maturation and class switch recombination (CSR) to change the effector function of the antibody. Both SHM and CSR are initiated by activation-induced cytidine deaminase (AID). Repair of AID-initiated lesions through different DNA repair pathways results in diverse mutagenic outcomes. Here, we focus on discussing cis- and trans-factors that target AID to its substrates and factors that affect different outcomes of AID-initiated lesions. The knowledge of mechanisms that govern AID targeting and outcomes could be harnessed to elicit rare functional antibodies and develop ex vivo antibody diversification approaches with diversifying base editors.
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Affiliation(s)
- Leng-Siew Yeap
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Fei-Long Meng
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China.
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52
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Balmus G, Pilger D, Coates J, Demir M, Sczaniecka-Clift M, Barros AC, Woods M, Fu B, Yang F, Chen E, Ostermaier M, Stankovic T, Ponstingl H, Herzog M, Yusa K, Martinez FM, Durant ST, Galanty Y, Beli P, Adams DJ, Bradley A, Metzakopian E, Forment JV, Jackson SP. ATM orchestrates the DNA-damage response to counter toxic non-homologous end-joining at broken replication forks. Nat Commun 2019; 10:87. [PMID: 30622252 PMCID: PMC6325118 DOI: 10.1038/s41467-018-07729-2] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 11/15/2018] [Indexed: 02/02/2023] Open
Abstract
Mutations in the ATM tumor suppressor gene confer hypersensitivity to DNA-damaging chemotherapeutic agents. To explore genetic resistance mechanisms, we performed genome-wide CRISPR-Cas9 screens in cells treated with the DNA topoisomerase I inhibitor topotecan. Thus, we here establish that inactivating terminal components of the non-homologous end-joining (NHEJ) machinery or of the BRCA1-A complex specifically confer topotecan resistance to ATM-deficient cells. We show that hypersensitivity of ATM-mutant cells to topotecan or the poly-(ADP-ribose) polymerase (PARP) inhibitor olaparib reflects delayed engagement of homologous recombination at DNA-replication-fork associated single-ended double-strand breaks (DSBs), allowing some to be subject to toxic NHEJ. Preventing DSB ligation by NHEJ, or enhancing homologous recombination by BRCA1-A complex disruption, suppresses this toxicity, highlighting a crucial role for ATM in preventing toxic LIG4-mediated chromosome fusions. Notably, suppressor mutations in ATM-mutant backgrounds are different to those in BRCA1-mutant scenarios, suggesting new opportunities for patient stratification and additional therapeutic vulnerabilities for clinical exploitation.
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Affiliation(s)
- Gabriel Balmus
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
- UK Dementia Research Institute and Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0AH, UK
| | - Domenic Pilger
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Julia Coates
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Mukerrem Demir
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Matylda Sczaniecka-Clift
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Ana C Barros
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Michael Woods
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Beiyuan Fu
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Fengtang Yang
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Elisabeth Chen
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | | | - Tatjana Stankovic
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Hannes Ponstingl
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Mareike Herzog
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Kosuke Yusa
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Francisco Munoz Martinez
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Stephen T Durant
- DNA Damage Response Biology, Bioscience Oncology IMED Biotech Unit, AstraZeneca, Cambridge, CB4 0WG, UK
| | - Yaron Galanty
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Petra Beli
- Institute of Molecular Biology (IMB), 55128, Mainz, Germany
| | - David J Adams
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Allan Bradley
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Emmanouil Metzakopian
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
- UK Dementia Research Institute and Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0AH, UK
| | - Josep V Forment
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.
- DNA Damage Response Biology, Bioscience Oncology IMED Biotech Unit, AstraZeneca, Cambridge, CB4 0WG, UK.
| | - Stephen P Jackson
- The Wellcome Trust and Cancer Research UK Gurdon Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.
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53
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Kinase-dead ATR differs from ATR loss by limiting the dynamic exchange of ATR and RPA. Nat Commun 2018; 9:5351. [PMID: 30559436 PMCID: PMC6297235 DOI: 10.1038/s41467-018-07798-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 11/27/2018] [Indexed: 12/21/2022] Open
Abstract
ATR kinase is activated by RPA-coated single-stranded DNA (ssDNA) to orchestrate DNA damage responses. Here we show that ATR inhibition differs from ATR loss. Mouse model expressing kinase-dead ATR (Atr+/KD), but not loss of ATR (Atr+/−), displays ssDNA-dependent defects at the non-homologous region of X-Y chromosomes during male meiosis leading to sterility, and at telomeres, rDNA, and fragile sites during mitosis leading to lymphocytopenia. Mechanistically, we find that ATR kinase activity is necessary for the rapid exchange of ATR at DNA-damage-sites, which in turn promotes CHK1-phosphorylation. ATR-KD, but not loss of ATR, traps a subset of ATR and RPA on chromatin, where RPA is hyper-phosphorylated by ATM/DNA-PKcs and prevents downstream repair. Consequently, Atr+/KD cells have shorter inter-origin distances and are vulnerable to induced fork collapses, genome instability and mitotic catastrophe. These results reveal mechanistic differences between ATR inhibition and ATR loss, with implications for ATR signaling and cancer therapy. ATR kinase is a key regulator of chromosome integrity. Here the authors by analysing the phenotype of a mouse model expressing a kinase-dead ATR, reveal the effect of ATR inhibition compared to ATR loss and its consequences for meiosis, DNA replication, checkpoint activation and genome instability .
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54
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Castañeda-Zegarra S, Xing M, Gago-Fuentes R, Sæterstad S, Oksenych V. Synthetic lethality between DNA repair factors Xlf and Paxx is rescued by inactivation of Trp53. DNA Repair (Amst) 2018; 73:164-169. [PMID: 30579708 DOI: 10.1016/j.dnarep.2018.12.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 12/04/2018] [Accepted: 12/14/2018] [Indexed: 02/03/2023]
Abstract
Non-homologous end joining (NHEJ) is a DNA repair pathway that senses, processes and ligates DNA double-strand breaks (DSBs) throughout the cell cycle. During NHEJ, core Ku70 and Ku80 subunits bind DSBs as a heterodimer and promote further recruitment of accessory factors (e.g., PAXX, Mri, DNA-PKcs, Artemis) and downstream core subunits XRCC4 and DNA ligase 4 (Lig4). Inactivation of Ku70 or Ku80 genes in mice results in immunodeficiency and high levels of genomic instability; deletion of individual Dna-pkcs, Xlf, Paxx or Mri genes results in viable mice with no or modest DNA repair defects. However, combined inactivation of either Xlf and Dna-pkcs, or Xlf and Paxx, or Xlf and Mri, leads to synthetic lethality in mice, which correlates with increased levels of apoptosis in the central nervous system. Here, we demonstrated that inactivation of pro-apoptotic factor Trp53 rescues embryonic lethality of Xlf-/-Paxx-/- and Xlf-/-Dna-pkcs-/- double knockout mice. Moreover, combined inactivation of Paxx and Dna-pkcs results in live-born fertile Paxx-/-Dna-pkcs-/- mice indistinguishable from Dna-pkcs-/- knockout controls.
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Affiliation(s)
- Sergio Castañeda-Zegarra
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Laboratory Center, Erling Skjalgssons gate 1, 7491, Trondheim, Norway; St. Olavs Hospital, Trondheim University Hospital, Clinic of Medicine, Postboks 3250 Sluppen, 7006, Trondheim, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Mengtan Xing
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Laboratory Center, Erling Skjalgssons gate 1, 7491, Trondheim, Norway; St. Olavs Hospital, Trondheim University Hospital, Clinic of Medicine, Postboks 3250 Sluppen, 7006, Trondheim, Norway
| | - Raquel Gago-Fuentes
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Laboratory Center, Erling Skjalgssons gate 1, 7491, Trondheim, Norway; St. Olavs Hospital, Trondheim University Hospital, Clinic of Medicine, Postboks 3250 Sluppen, 7006, Trondheim, Norway
| | - Siri Sæterstad
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Laboratory Center, Erling Skjalgssons gate 1, 7491, Trondheim, Norway; St. Olavs Hospital, Trondheim University Hospital, Clinic of Medicine, Postboks 3250 Sluppen, 7006, Trondheim, Norway
| | - Valentyn Oksenych
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Laboratory Center, Erling Skjalgssons gate 1, 7491, Trondheim, Norway; St. Olavs Hospital, Trondheim University Hospital, Clinic of Medicine, Postboks 3250 Sluppen, 7006, Trondheim, Norway; Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.
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55
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PAXX and its paralogs synergistically direct DNA polymerase λ activity in DNA repair. Nat Commun 2018; 9:3877. [PMID: 30250067 PMCID: PMC6155126 DOI: 10.1038/s41467-018-06127-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 08/09/2018] [Indexed: 12/20/2022] Open
Abstract
PAXX is a recently identified component of the nonhomologous end joining (NHEJ) DNA repair pathway. The molecular mechanisms of PAXX action remain largely unclear. Here we characterise the interactomes of PAXX and its paralogs, XLF and XRCC4, to show that these factors share the ability to interact with DNA polymerase λ (Pol λ), stimulate its activity and are required for recruitment of Pol λ to laser-induced DNA damage sites. Stimulation of Pol λ activity by XRCC4 paralogs requires a direct interaction between the SP/8 kDa domain of Pol λ and their N-terminal head domains to facilitate recognition of the 5′ end of substrate gaps. Furthermore, PAXX and XLF collaborate with Pol λ to promote joining of incompatible DNA ends and are redundant in supporting Pol λ function in vivo. Our findings identify Pol λ as a novel downstream effector of PAXX function and show XRCC4 paralogs act in synergy to regulate polymerase activity in NHEJ. PAXX functions as part of the nonhomologous end-joining pathway to repair double-strand DNA breaks. Here the authors show PAXX and its paralogs interact with polymerase lambda to promote joining of incompatible ends.
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56
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PAXX Participates in Base Excision Repair via Interacting with Pol β and Contributes to TMZ Resistance in Glioma Cells. J Mol Neurosci 2018; 66:214-221. [PMID: 30238427 PMCID: PMC6182633 DOI: 10.1007/s12031-018-1157-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 08/06/2018] [Indexed: 12/29/2022]
Abstract
Non-homologous end joining (NHEJ) is one of the major DNA repair pathway in mammalian cell that can ligate a variety of DNA ends. However, how does all NHEJ factors communicate and organize together to achieve the final repair is still not clear. PAralog of XRCC4 and XLF (PAXX) was a new factor identified recently that play an important role in NHEJ. PAXX contributes to efficient NHEJ by interacting with Ku, which is a NHEJ key factor, and PAXX deficiency cause sensitivity to DNA double-strand break repair (DSBR). We observed that PAXX-deficient cells showed slight increase of homologous recombination (HR, which is another major DSBR repair pathways in mammalian cells). More importantly, we found that PAXX contributes to base excision repair pathway via interaction of polymerase beta (pol β). Temozolomide (TMZ) is one of the standard chemotherapies widely applied in glioblastoma. However, TMZ resistance and lack of potent chemotherapy agents can substitute TMZ. We observed that PAXX deficiency cause more sensitivity to TMZ-resistant glioma cells. In conclusion, the PAXX contributes to a variety of DNA repair pathways and TMZ resistance. Therefore, inhibition of PAXX may provide a promising way to overcome TMZ resistance and improve TMZ therapeutic effects in glioma treatment.
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57
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Kinase-dependent structural role of DNA-PKcs during immunoglobulin class switch recombination. Proc Natl Acad Sci U S A 2018; 115:8615-8620. [PMID: 30072430 DOI: 10.1073/pnas.1808490115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) is a classical nonhomologous end-joining (cNHEJ) factor. Loss of DNA-PKcs diminished mature B cell class switch recombination (CSR) to other isotypes, but not IgG1. Here, we show that expression of the kinase-dead DNA-PKcs (DNA-PKcsKD/KD ) severely compromises CSR to IgG1. High-throughput sequencing analyses of CSR junctions reveal frequent accumulation of nonproductive interchromosomal translocations, inversions, and extensive end resection in DNA-PKcsKD/KD , but not DNA-PKcs-/- , B cells. Meanwhile, the residual joints from DNA-PKcsKD/KD cells and the efficient Sµ-Sγ1 junctions from DNA-PKcs-/- B cells both display similar preferences for small (2-6 nt) microhomologies (MH). In DNA-PKcs-/- cells, Sµ-Sγ1 joints are more resistant to inversions and extensive resection than Sµ-Sε and Sµ-Sµ joints, providing a mechanism for the isotype-specific CSR defects. Together, our findings identify a kinase-dependent role of DNA-PKcs in suppressing MH-mediated end joining and a structural role of DNA-PKcs protein in the orientation of CSR.
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58
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Hung PJ, Johnson B, Chen BR, Byrum AK, Bredemeyer AL, Yewdell WT, Johnson TE, Lee BJ, Deivasigamani S, Hindi I, Amatya P, Gross ML, Paull TT, Pisapia DJ, Chaudhuri J, Petrini JJH, Mosammaparast N, Amarasinghe GK, Zha S, Tyler JK, Sleckman BP. MRI Is a DNA Damage Response Adaptor during Classical Non-homologous End Joining. Mol Cell 2018; 71:332-342.e8. [PMID: 30017584 PMCID: PMC6083883 DOI: 10.1016/j.molcel.2018.06.018] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 05/20/2018] [Accepted: 06/07/2018] [Indexed: 11/15/2022]
Abstract
The modulator of retrovirus infection (MRI or CYREN) is a 30-kDa protein with a conserved N-terminal Ku-binding motif (KBM) and a C-terminal XLF-like motif (XLM). We show that MRI is intrinsically disordered and interacts with many DNA damage response (DDR) proteins, including the kinases ataxia telangiectasia mutated (ATM) and DNA-PKcs and the classical non-homologous end joining (cNHEJ) factors Ku70, Ku80, XRCC4, XLF, PAXX, and XRCC4. MRI forms large multimeric complexes that depend on its N and C termini and localizes to DNA double-strand breaks (DSBs), where it promotes the retention of DDR factors. Mice deficient in MRI and XLF exhibit embryonic lethality at a stage similar to those deficient in the core cNHEJ factors XRCC4 or DNA ligase IV. Moreover, MRI is required for cNHEJ-mediated DSB repair in XLF-deficient lymphocytes. We propose that MRI is an adaptor that, through multivalent interactions, increases the avidity of DDR factors to DSB-associated chromatin to promote cNHEJ.
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Affiliation(s)
- Putzer J Hung
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY 10065, USA; Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Britney Johnson
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Bo-Ruei Chen
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Andrea K Byrum
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Andrea L Bredemeyer
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - William T Yewdell
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Tanya E Johnson
- The Department of Molecular Biosciences and the Howard Hughes Medical Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Brian J Lee
- Institute for Cancer Genetics, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Shruthi Deivasigamani
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Issa Hindi
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Parmeshwar Amatya
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael L Gross
- Department of Chemistry, Washington University, One Brookings Drive, St. Louis, MO 63130, USA
| | - Tanya T Paull
- The Department of Molecular Biosciences and the Howard Hughes Medical Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - David J Pisapia
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Jayanta Chaudhuri
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - John J H Petrini
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Nima Mosammaparast
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Gaya K Amarasinghe
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Shan Zha
- Institute for Cancer Genetics, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Jessica K Tyler
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Barry P Sleckman
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY 10065, USA.
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Bhargava R, Sandhu M, Muk S, Lee G, Vaidehi N, Stark JM. C-NHEJ without indels is robust and requires synergistic function of distinct XLF domains. Nat Commun 2018; 9:2484. [PMID: 29950655 PMCID: PMC6021437 DOI: 10.1038/s41467-018-04867-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 05/25/2018] [Indexed: 01/17/2023] Open
Abstract
To investigate the fidelity of canonical non-homologous end joining (C-NHEJ), we developed an assay to detect EJ between distal ends of two Cas9-induced chromosomal breaks that are joined without causing insertion/deletion mutations (indels). Here we find that such EJ requires several core C-NHEJ factors, including XLF. Using variants of this assay, we find that C-NHEJ is required for EJ events that use 1-2, but not ≥3, nucleotides of terminal microhomology. We also investigated XLF residues required for EJ without indels, finding that one of two binding domains is essential (L115 or C-terminal lysines that bind XRCC4 and KU/DNA, respectively), and that disruption of one of these domains sensitizes XLF to mutations that affect its dimer interface, which we examined with molecular dynamic simulations. Thus, C-NHEJ, including synergistic function of distinct XLF domains, is required for EJ of chromosomal breaks without indels.
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Affiliation(s)
- Ragini Bhargava
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA, 91010, USA
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA, 91010, USA
| | - Manbir Sandhu
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA, 91010, USA
- Department of Molecular Immunology, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA, 91010, USA
| | - Sanychen Muk
- Department of Molecular Immunology, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA, 91010, USA
| | - Gabriella Lee
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA, 91010, USA
| | - Nagarajan Vaidehi
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA, 91010, USA
- Department of Molecular Immunology, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA, 91010, USA
| | - Jeremy M Stark
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA, 91010, USA.
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA, 91010, USA.
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60
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Dissection of DNA double-strand-break repair using novel single-molecule forceps. Nat Struct Mol Biol 2018; 25:482-487. [PMID: 29786079 PMCID: PMC5990469 DOI: 10.1038/s41594-018-0065-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 04/13/2018] [Indexed: 02/02/2023]
Abstract
Repairing DNA double-strand breaks (DSBs) by nonhomologous end joining (NHEJ) requires multiple proteins to recognize and bind DNA ends, process them for compatibility, and ligate them together. We constructed novel DNA substrates for single-molecule nanomanipulation, allowing us to mechanically detect, probe, and rupture in real-time DSB synapsis by specific human NHEJ components. DNA-PKcs and Ku allow DNA end synapsis on the 100 ms timescale, and the addition of PAXX extends this lifetime to ~2 s. Further addition of XRCC4, XLF and ligase IV results in minute-scale synapsis and leads to robust repair of both strands of the nanomanipulated DNA. The energetic contribution of the different components to synaptic stability is typically on the scale of a few kilocalories per mole. Our results define assembly rules for NHEJ machinery and unveil the importance of weak interactions, rapidly ruptured even at sub-picoNewton forces, in regulating this multicomponent chemomechanical system for genome integrity.
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61
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Helena JM, Joubert AM, Grobbelaar S, Nolte EM, Nel M, Pepper MS, Coetzee M, Mercier AE. Deoxyribonucleic Acid Damage and Repair: Capitalizing on Our Understanding of the Mechanisms of Maintaining Genomic Integrity for Therapeutic Purposes. Int J Mol Sci 2018; 19:E1148. [PMID: 29641431 PMCID: PMC5979424 DOI: 10.3390/ijms19041148] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 03/19/2018] [Accepted: 03/23/2018] [Indexed: 12/31/2022] Open
Abstract
Deoxyribonucleic acid (DNA) is the self-replicating hereditary material that provides a blueprint which, in collaboration with environmental influences, produces a structural and functional phenotype. As DNA coordinates and directs differentiation, growth, survival, and reproduction, it is responsible for life and the continuation of our species. Genome integrity requires the maintenance of DNA stability for the correct preservation of genetic information. This is facilitated by accurate DNA replication and precise DNA repair. DNA damage may arise from a wide range of both endogenous and exogenous sources but may be repaired through highly specific mechanisms. The most common mechanisms include mismatch, base excision, nucleotide excision, and double-strand DNA (dsDNA) break repair. Concurrent with regulation of the cell cycle, these mechanisms are precisely executed to ensure full restoration of damaged DNA. Failure or inaccuracy in DNA repair contributes to genome instability and loss of genetic information which may lead to mutations resulting in disease or loss of life. A detailed understanding of the mechanisms of DNA damage and its repair provides insight into disease pathogeneses and may facilitate diagnosis and the development of targeted therapies.
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Affiliation(s)
- Jolene Michelle Helena
- Department of Physiology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria 0002, South Africa.
| | - Anna Margaretha Joubert
- Department of Physiology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria 0002, South Africa.
| | - Simone Grobbelaar
- Department of Physiology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria 0002, South Africa.
| | - Elsie Magdalena Nolte
- Department of Physiology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria 0002, South Africa.
| | - Marcel Nel
- Department of Physiology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria 0002, South Africa.
| | - Michael Sean Pepper
- Institute for Cellular and Molecular Medicine, Department of Immunology, South African Medical Research Council (SAMRC) Extramural Unit for Stem Cell Research and Therapy, Faculty of Health Sciences, University of Pretoria, Pretoria 0002, South Africa.
| | - Magdalena Coetzee
- Department of Physiology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria 0002, South Africa.
| | - Anne Elisabeth Mercier
- Department of Physiology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria 0002, South Africa.
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Dewan A, Xing M, Lundbæk MB, Gago‐Fuentes R, Beck C, Aas PA, Liabakk N, Sæterstad S, Chau KTP, Kavli BM, Oksenych V. Robust DNA repair in PAXX-deficient mammalian cells. FEBS Open Bio 2018; 8:442-448. [PMID: 29511621 PMCID: PMC5832976 DOI: 10.1002/2211-5463.12380] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 12/19/2017] [Accepted: 01/04/2018] [Indexed: 12/02/2022] Open
Abstract
To ensure genome stability, mammalian cells employ several DNA repair pathways. Nonhomologous DNA end joining (NHEJ) is the DNA repair process that fixes double-strand breaks throughout the cell cycle. NHEJ is involved in the development of B and T lymphocytes through its function in V(D)J recombination and class switch recombination (CSR). NHEJ consists of several core and accessory factors, including Ku70, Ku80, XRCC4, DNA ligase 4, DNA-PKcs, Artemis, and XLF. Paralog of XRCC4 and XLF (PAXX) is the recently described accessory NHEJ factor that structurally resembles XRCC4 and XLF and interacts with Ku70/Ku80. To determine the physiological role of PAXX in mammalian cells, we purchased and characterized a set of custom-generated and commercially available NHEJ-deficient human haploid HAP1 cells, PAXXΔ, XRCC4Δ , and XLFΔ . In our studies, HAP1 PAXXΔ cells demonstrated modest sensitivity to DNA damage, which was comparable to wild-type controls. By contrast, XRCC4Δ and XLFΔ HAP1 cells possessed significant DNA repair defects measured as sensitivity to double-strand break inducing agents and chromosomal breaks. To investigate the role of PAXX in CSR, we generated and characterized Paxx-/- and Aid-/- murine lymphoid CH12F3 cells. CSR to IgA was nearly at wild-type levels in the Paxx-/- cells and completely ablated in the absence of activation-induced cytidine deaminase (AID). In addition, Paxx-/- CH12F3 cells were hypersensitive to zeocin when compared to wild-type controls. We concluded that Paxx-deficient mammalian cells maintain robust NHEJ and CSR.
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Affiliation(s)
- Alisa Dewan
- Department of Clinical and Molecular Medicine (IKOM)Norwegian University of Science and TechnologyTrondheimNorway
- Present address:
Centre for Immune Regulation and Department of ImmunologyUniversity of Oslo and Oslo University Hospital‐RikshospitaletOsloNorway
- Present address:
KG Jebsen Coeliac Disease Research CentreUniversity of OsloOsloNorway
| | - Mengtan Xing
- Department of Clinical and Molecular Medicine (IKOM)Norwegian University of Science and TechnologyTrondheimNorway
| | - Marie Benner Lundbæk
- Department of Clinical and Molecular Medicine (IKOM)Norwegian University of Science and TechnologyTrondheimNorway
| | - Raquel Gago‐Fuentes
- Department of Clinical and Molecular Medicine (IKOM)Norwegian University of Science and TechnologyTrondheimNorway
| | - Carole Beck
- Department of Clinical and Molecular Medicine (IKOM)Norwegian University of Science and TechnologyTrondheimNorway
| | - Per Arne Aas
- Department of Clinical and Molecular Medicine (IKOM)Norwegian University of Science and TechnologyTrondheimNorway
| | - Nina‐Beate Liabakk
- Department of Clinical and Molecular Medicine (IKOM)Norwegian University of Science and TechnologyTrondheimNorway
| | - Siri Sæterstad
- Department of Clinical and Molecular Medicine (IKOM)Norwegian University of Science and TechnologyTrondheimNorway
| | - Khac Thanh Phong Chau
- Department of Clinical and Molecular Medicine (IKOM)Norwegian University of Science and TechnologyTrondheimNorway
| | - Bodil Merete Kavli
- Department of Clinical and Molecular Medicine (IKOM)Norwegian University of Science and TechnologyTrondheimNorway
| | - Valentyn Oksenych
- Department of Clinical and Molecular Medicine (IKOM)Norwegian University of Science and TechnologyTrondheimNorway
- St. Olavs HospitalTrondheim University Hospital, Clinic of MedicineNorway
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63
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Gago‐Fuentes R, Xing M, Sæterstad S, Sarno A, Dewan A, Beck C, Bradamante S, Bjørås M, Oksenych V. Normal development of mice lacking PAXX, the paralogue of XRCC4 and XLF. FEBS Open Bio 2018; 8:426-434. [PMID: 29511619 PMCID: PMC5832975 DOI: 10.1002/2211-5463.12381] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 12/18/2017] [Accepted: 01/04/2018] [Indexed: 02/05/2023] Open
Abstract
DNA repair consists of several cellular pathways which recognize and repair damaged DNA. The classical nonhomologous DNA end-joining (NHEJ) pathway repairs double-strand breaks in DNA. It is required for maturation of both B and T lymphocytes by supporting V(D)J recombination as well as B-cell differentiation during class switch recombination (CSR). Inactivation of NHEJ factors Ku70, Ku80, XRCC4, DNA ligase 4, DNA-PKcs, and Artemis impairs V(D)J recombination and blocks lymphocyte development. Paralogue of XRCC4 and XLF (PAXX) is an accessory NHEJ factor that has a significant impact on the repair of DNA lesions induced by ionizing radiation in human, murine, and chicken cells. However, the role of PAXX during development is poorly understood. To determine the physiological role of PAXX, we deleted part of the Paxx promoter and the first two exons in mice. Further, we compared Paxx-knockout mice with wild-type (WT) and NHEJ-deficient controls including Ku80- and Dna-pkcs-null and severe combined immunodeficiency mice. Surprisingly, Paxx-deficient mice were not distinguishable from the WT littermates; they were the same weight and size, fertility status, had normal spleen, thymus, and bone marrow. Paxx-deficient mice had the same number of chromosomal and chromatid breaks as WT mice. Moreover, Paxx-deficient primary B lymphocytes had the same level of CSR as lymphocytes isolated from WT mice. We concluded that PAXX is dispensable for normal mouse development.
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Affiliation(s)
- Raquel Gago‐Fuentes
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
| | - Mengtan Xing
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
| | - Siri Sæterstad
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
| | - Antonio Sarno
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
- St. Olavs HospitalClinic of MedicineTrondheim University HospitalTrondheimNorway
| | - Alisa Dewan
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
- Present address:
Centre for Immune Regulation and Department of ImmunologyOslo University Hospital‐RikshospitaletUniversity of OsloOsloNorway
- Present address:
KG Jebsen Coeliac Disease Research CentreUniversity of OsloOsloNorway
| | - Carole Beck
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
| | - Stefano Bradamante
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
| | - Magnar Bjørås
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
- Department of MicrobiologyOslo University HospitalUniversity of OsloOsloNorway
| | - Valentyn Oksenych
- Institute of Clinical and Molecular Medicine (IKOM)Laboratory CenterNorwegian University of Science and TechnologyTrondheimNorway
- St. Olavs HospitalClinic of MedicineTrondheim University HospitalTrondheimNorway
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64
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Pannunzio NR, Watanabe G, Lieber MR. Nonhomologous DNA end-joining for repair of DNA double-strand breaks. J Biol Chem 2017; 293:10512-10523. [PMID: 29247009 DOI: 10.1074/jbc.tm117.000374] [Citation(s) in RCA: 326] [Impact Index Per Article: 46.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Nonhomologous DNA end-joining (NHEJ) is the predominant double-strand break (DSB) repair pathway throughout the cell cycle and accounts for nearly all DSB repair outside of the S and G2 phases. NHEJ relies on Ku to thread onto DNA termini and thereby improve the affinity of the NHEJ enzymatic components consisting of polymerases (Pol μ and Pol λ), a nuclease (the Artemis·DNA-PKcs complex), and a ligase (XLF·XRCC4·Lig4 complex). Each of the enzymatic components is distinctive for its versatility in acting on diverse incompatible DNA end configurations coupled with a flexibility in loading order, resulting in many possible junctional outcomes from one DSB. DNA ends can either be directly ligated or, if the ends are incompatible, processed until a ligatable configuration is achieved that is often stabilized by up to 4 bp of terminal microhomology. Processing of DNA ends results in nucleotide loss or addition, explaining why DSBs repaired by NHEJ are rarely restored to their original DNA sequence. Thus, NHEJ is a single pathway with multiple enzymes at its disposal to repair DSBs, resulting in a diversity of repair outcomes.
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Affiliation(s)
- Nicholas R Pannunzio
- From the Departments of Pathology, Biochemistry and Molecular Biology, and Molecular Microbiology and Immunology, Section of Molecular and Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
| | - Go Watanabe
- From the Departments of Pathology, Biochemistry and Molecular Biology, and Molecular Microbiology and Immunology, Section of Molecular and Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
| | - Michael R Lieber
- From the Departments of Pathology, Biochemistry and Molecular Biology, and Molecular Microbiology and Immunology, Section of Molecular and Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
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65
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Trigg BJ, Lauer KB, Fernandes Dos Santos P, Coleman H, Balmus G, Mansur DS, Ferguson BJ. The Non-Homologous End Joining Protein PAXX Acts to Restrict HSV-1 Infection. Viruses 2017; 9:E342. [PMID: 29144403 PMCID: PMC5707549 DOI: 10.3390/v9110342] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/02/2017] [Accepted: 11/06/2017] [Indexed: 01/27/2023] Open
Abstract
Herpes simplex virus 1 (HSV-1) has extensive interactions with the host DNA damage response (DDR) machinery that can be either detrimental or beneficial to the virus. Proteins in the homologous recombination pathway are known to be required for efficient replication of the viral genome, while different members of the classical non-homologous end-joining (c-NHEJ) pathway have opposing effects on HSV-1 infection. Here, we have investigated the role of the recently-discovered c-NHEJ component, PAXX (Paralogue of XRCC4 and XLF), which we found to be excluded from the nucleus during HSV-1 infection. We have established that cells lacking PAXX have an intact innate immune response to HSV-1 but show a defect in viral genome replication efficiency. Counterintuitively, PAXX-/- cells were able to produce greater numbers of infectious virions, indicating that PAXX acts to restrict HSV-1 infection in a manner that is different from other c-NHEJ factors.
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Affiliation(s)
- Ben J Trigg
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
| | - Katharina B Lauer
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
| | - Paula Fernandes Dos Santos
- Laboratory of Immunobiology, Department of Microbiology, Immunology and Parasitology, Universidade Federal de Santa Catarina, Santa Catarina 88040-900, Brazil.
| | - Heather Coleman
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
| | - Gabriel Balmus
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK.
- Wellcome Trust Sanger Institute, Cambridge CB10 1HH, UK.
| | - Daniel S Mansur
- Laboratory of Immunobiology, Department of Microbiology, Immunology and Parasitology, Universidade Federal de Santa Catarina, Santa Catarina 88040-900, Brazil.
| | - Brian J Ferguson
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
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66
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PAXX and Xlf interplay revealed by impaired CNS development and immunodeficiency of double KO mice. Cell Death Differ 2017; 25:444-452. [PMID: 29077092 DOI: 10.1038/cdd.2017.184] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/19/2017] [Accepted: 09/21/2017] [Indexed: 12/26/2022] Open
Abstract
The repair of DNA double-stranded breaks (DNAdsb) through non-homologous end joining (NHEJ) is a prerequisite for the proper development of the central nervous system and the adaptive immune system. Yet, mice with Xlf or PAXX loss of function are viable and present with very mild immune phenotypes, although their lymphoid cells are sensitive to ionizing radiation attesting for the role of these factors in NHEJ. In contrast, we show here that mice defective for both Xlf and PAXX are embryonically lethal owing to a massive apoptosis of post-mitotic neurons, a situation reminiscent to XRCC4 or DNA Ligase IV KO conditions. The development of the adaptive immune system in Xlf-/-PAXX-/- E18.5 embryos is severely affected with the block of B- and T-cell maturation at the stage of IgH and TCRβ gene rearrangements, respectively. This damaging phenotype highlights the functional nexus between Xlf and PAXX, which is critical for the completion of NHEJ-dependent mechanisms during mouse development.
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67
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Lenden Hasse H, Lescale C, Bianchi JJ, Yu W, Bedora-Faure M, Deriano L. Generation and CRISPR/Cas9 editing of transformed progenitor B cells as a pseudo-physiological system to study DNA repair gene function in V(D)J recombination. J Immunol Methods 2017; 451:71-77. [PMID: 28882611 PMCID: PMC5714433 DOI: 10.1016/j.jim.2017.08.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 08/22/2017] [Accepted: 08/22/2017] [Indexed: 11/18/2022]
Abstract
Antigen receptor gene assembly is accomplished in developing lymphocytes by the V(D)J recombination reaction, which can be separated into two steps: DNA cleavage by the recombination-activating gene (RAG) nuclease and joining of DNA double strand breaks (DSBs) by components of the nonhomologous end joining (NHEJ) pathway. Deficiencies for NHEJ factors can result in immunodeficiency and a propensity to accumulate genomic instability, thus highlighting the importance of identifying all players in this process and deciphering their functions. Bcl2 transgenic v-Abl kinase-transformed pro-B cells provide a pseudo-physiological cellular system to study V(D)J recombination. Treatment of v-Abl/Bcl2 pro-B cells with the Abl kinase inhibitor Imatinib leads to G1 cell cycle arrest, the rapid induction of Rag1/2 gene expression and V(D)J recombination. In this system, the Bcl2 transgene alleviates Imatinib-induced apoptosis enabling the analysis of induced V(D)J recombination. Although powerful, the use of mouse models carrying the Bcl2 transgene for the generation of v-Abl pro-B cell lines is time and money consuming. Here, we describe a method for generating v-Abl/Bcl2 pro-B cell lines from wild type mice and for performing gene knock-out using episomal CRISPR/Cas9 targeting vectors. Using this approach, we generated distinct NHEJ-deficient pro-B cell lines and quantified V(D)J recombination levels in these cells. Furthermore, this methodology can be adapted to generate pro-B cell lines deficient for any gene suspected to play a role in V(D)J recombination, and more generally DSB repair.
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Affiliation(s)
- Hélène Lenden Hasse
- Genome Integrity, Immunity and Cancer Unit, Department of Immunology, Department of Genomes and Genetics, Institut Pasteur, 75015 Paris, France
| | - Chloé Lescale
- Genome Integrity, Immunity and Cancer Unit, Department of Immunology, Department of Genomes and Genetics, Institut Pasteur, 75015 Paris, France
| | - Joy J Bianchi
- Genome Integrity, Immunity and Cancer Unit, Department of Immunology, Department of Genomes and Genetics, Institut Pasteur, 75015 Paris, France; Cellule Pasteur, University of Paris René Descartes, Sorbonne Paris Cité, Paris 75015, France
| | - Wei Yu
- Genome Integrity, Immunity and Cancer Unit, Department of Immunology, Department of Genomes and Genetics, Institut Pasteur, 75015 Paris, France
| | - Marie Bedora-Faure
- Genome Integrity, Immunity and Cancer Unit, Department of Immunology, Department of Genomes and Genetics, Institut Pasteur, 75015 Paris, France
| | - Ludovic Deriano
- Genome Integrity, Immunity and Cancer Unit, Department of Immunology, Department of Genomes and Genetics, Institut Pasteur, 75015 Paris, France.
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68
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Xing M, Bjørås M, Daniel JA, Alt FW, Oksenych V. Synthetic lethality between murine DNA repair factors XLF and DNA-PKcs is rescued by inactivation of Ku70. DNA Repair (Amst) 2017; 57:133-138. [PMID: 28759779 PMCID: PMC5584571 DOI: 10.1016/j.dnarep.2017.07.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 06/25/2017] [Accepted: 07/24/2017] [Indexed: 11/18/2022]
Abstract
DNA double-strand breaks (DSBs) are recognized and repaired by the Classical Non-Homologous End-Joining (C-NHEJ) and Homologous Recombination pathways. C-NHEJ includes the core Ku70 and Ku80 (or Ku86) heterodimer that binds DSBs and thus promotes recruitment of accessory downstream NHEJ factors XLF, PAXX, DNA-PKcs, Artemis and other core subunits, XRCC4 and DNA Ligase 4 (Lig4). In the absence of core C-NHEJ factors, DNA repair can be performed by Alternative End-Joining, which likely depends on DNA Ligase 1 and DNA Ligase 3. Genetic inactivation of C-NHEJ factors, such as Ku70, Ku80, XLF, PAXX and DNA-PKcs results in viable mice showing increased levels of genomic instability and sensitivity to DSBs. Knockouts of XRCC4 or Lig4, on the other hand, as well as combined inactivation of XLF and DNA-PKcs, or XLF and PAXX, result in late embryonic lethality in mice, which in most cases correlate with severe apoptosis in the central nervous system. Here, we demonstrate that inactivation of the Ku70 gene rescues the synthetic lethality between XLF and DNA-PKcs, resulting in triple knockout mice that are indistinguishable from Ku70-deficient littermates by size or levels of genomic instability. Moreover, we find that combined inactivation of Ku70 and XLF results in viable mice. Together, these findings suggest that Ku70 is epistatic with XLF and DNA-PKcs and support a model in which inactivation of Ku70 allows DNA lesions to become accessible to alternative DNA repair pathways.
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Affiliation(s)
- Mengtan Xing
- Institute for Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Laboratory Center, Erling Skjalgssons Gate 1, 7491 Trondheim, Norway
| | - Magnar Bjørås
- Institute for Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Laboratory Center, Erling Skjalgssons Gate 1, 7491 Trondheim, Norway
| | - Jeremy A Daniel
- The NNF Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Frederick W Alt
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Department of Genetics, Harvard Medical School, Boston, MA 02115, United States.
| | - Valentyn Oksenych
- Institute for Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Laboratory Center, Erling Skjalgssons Gate 1, 7491 Trondheim, Norway; The NNF Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark; Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Department of Genetics, Harvard Medical School, Boston, MA 02115, United States; St. Olavs Hospital, Trondheim University Hospital, Clinic of Medicine, Postboks 3250 Sluppen, 7006 Trondheim, Norway.
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69
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Blackford AN, Jackson SP. ATM, ATR, and DNA-PK: The Trinity at the Heart of the DNA Damage Response. Mol Cell 2017; 66:801-817. [PMID: 28622525 DOI: 10.1016/j.molcel.2017.05.015] [Citation(s) in RCA: 1167] [Impact Index Per Article: 166.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 04/28/2017] [Accepted: 05/16/2017] [Indexed: 01/09/2023]
Abstract
In vertebrate cells, the DNA damage response is controlled by three related kinases: ATM, ATR, and DNA-PK. It has been 20 years since the cloning of ATR, the last of the three to be identified. During this time, our understanding of how these kinases regulate DNA repair and associated events has grown profoundly, although major questions remain unanswered. Here, we provide a historical perspective of their discovery and discuss their established functions in sensing and responding to genotoxic stress. We also highlight what is known regarding their structural similarities and common mechanisms of regulation, as well as emerging non-canonical roles and how our knowledge of ATM, ATR, and DNA-PK is being translated to benefit human health.
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Affiliation(s)
- Andrew N Blackford
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK; Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK; Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK.
| | - Stephen P Jackson
- Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK; Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK.
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70
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Non-homologous DNA end joining and alternative pathways to double-strand break repair. Nat Rev Mol Cell Biol 2017; 18:495-506. [PMID: 28512351 DOI: 10.1038/nrm.2017.48] [Citation(s) in RCA: 997] [Impact Index Per Article: 142.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
DNA double-strand breaks (DSBs) are the most dangerous type of DNA damage because they can result in the loss of large chromosomal regions. In all mammalian cells, DSBs that occur throughout the cell cycle are repaired predominantly by the non-homologous DNA end joining (NHEJ) pathway. Defects in NHEJ result in sensitivity to ionizing radiation and the ablation of lymphocytes. The NHEJ pathway utilizes proteins that recognize, resect, polymerize and ligate the DNA ends in a flexible manner. This flexibility permits NHEJ to function on a wide range of DNA-end configurations, with the resulting repaired DNA junctions often containing mutations. In this Review, we discuss the most recent findings regarding the relative involvement of the different NHEJ proteins in the repair of various DNA-end configurations. We also discuss the shunting of DNA-end repair to the auxiliary pathways of alternative end joining (a-EJ) or single-strand annealing (SSA) and the relevance of these different pathways to human disease.
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71
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Graham TGW, Walter JC, Loparo JJ. Ensemble and Single-Molecule Analysis of Non-Homologous End Joining in Frog Egg Extracts. Methods Enzymol 2017. [PMID: 28645371 DOI: 10.1016/bs.mie.2017.03.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Non-homologous end joining (NHEJ) repairs the majority of DNA double-strand breaks in human cells, yet the detailed order of events in this process has remained obscure. Here, we describe how to employ Xenopus laevis egg extract for the study of NHEJ. The egg extract is easy to prepare in large quantities, and it performs efficient end joining that requires the core end joining proteins Ku, DNA-PKcs, XLF, XRCC4, and DNA ligase IV. These factors, along with the rest of the soluble proteome, are present at endogenous concentrations, allowing mechanistic analysis in a system that begins to approximate the complexity of cellular end joining. We describe an ensemble assay that monitors covalent joining of DNA ends and fluorescence assays that detect joining of single pairs of DNA ends. The latter assay discerns at least two discrete intermediates in the bridging of DNA ends.
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Affiliation(s)
| | - Johannes C Walter
- Harvard Medical School, Boston, MA, United States; Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, United States.
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