151
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McBride KM, Kil H, Mu Y, Plummer JB, Lee J, Zelazowski MJ, Sebastian M, Abba MC, Aldaz CM. Wwox Deletion in Mouse B Cells Leads to Genomic Instability, Neoplastic Transformation, and Monoclonal Gammopathies. Front Oncol 2019; 9:517. [PMID: 31275852 PMCID: PMC6593956 DOI: 10.3389/fonc.2019.00517] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 05/29/2019] [Indexed: 01/18/2023] Open
Abstract
WWOX (WW domain containing oxidoreductase) expression loss is common in various cancers and characteristic of poor prognosis. Deletions, translocations, and loss of expression affecting the WWOX gene are a common feature of various B cell neoplasms such as certain B cell lymphomas and multiple myeloma. However, the role of this common abnormality in B cell tumor initiation and/or progression has not been defined. In this study, we conditionally deleted Wwox early in B cell development by means of breeding Cd19-Cre transgenic mice crossed to Wwox floxed mice (Cd19 Wwox KO). We observed a significant reduced survival in Cd19 Wwox KO mice and the development of B cell neoplasms including B cell lymphomas, plasma cell neoplasias characterized by increased numbers of CD138+ populations as well as monoclonal gammopathies detected by serum protein electrophoresis. To investigate whether Wwox loss could play a role in genomic instability, we analyzed DNA repair functions during immunoglobulin class switch joining between DNA segments in antibody genes. While class switch recombination (CSR) was only slightly impaired, Wwox deficiency resulted in a dramatic shift of double strand break (DSB) repair from normal classical-NHEJ toward the microhomology-mediated alternative-NHEJ pathway, a pathway associated with chromosome translocations and genome instability. Consistent with this, Wwox deficiency resulted in a marked increase of spontaneous translocations during CSR. This work defines for the first time a role for Wwox for maintaining B cell genome stability during a process that can promote neoplastic transformation and monoclonal gammopathies.
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Affiliation(s)
- Kevin M McBride
- Department of Epigenetics and Molecular Carcinogenesis, Science Park, The University of Texas MD Anderson Cancer Center, Smithville, TX, United States
| | - Hyunsuk Kil
- Department of Epigenetics and Molecular Carcinogenesis, Science Park, The University of Texas MD Anderson Cancer Center, Smithville, TX, United States
| | - Yunxiang Mu
- Department of Epigenetics and Molecular Carcinogenesis, Science Park, The University of Texas MD Anderson Cancer Center, Smithville, TX, United States
| | - Joshua B Plummer
- Department of Epigenetics and Molecular Carcinogenesis, Science Park, The University of Texas MD Anderson Cancer Center, Smithville, TX, United States
| | - Jaeho Lee
- Department of Epigenetics and Molecular Carcinogenesis, Science Park, The University of Texas MD Anderson Cancer Center, Smithville, TX, United States
| | - Maciej J Zelazowski
- Department of Epigenetics and Molecular Carcinogenesis, Science Park, The University of Texas MD Anderson Cancer Center, Smithville, TX, United States
| | - Manu Sebastian
- Department of Epigenetics and Molecular Carcinogenesis, Science Park, The University of Texas MD Anderson Cancer Center, Smithville, TX, United States
| | - Martin C Abba
- School of Medicine, Center for Immunological Basic and Applied Research (CINIBA), National University of La Plata (UNLP), La Plata, Argentina
| | - C Marcelo Aldaz
- Department of Epigenetics and Molecular Carcinogenesis, Science Park, The University of Texas MD Anderson Cancer Center, Smithville, TX, United States
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152
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Mladenov E, Fan X, Dueva R, Soni A, Iliakis G. Radiation-dose-dependent functional synergisms between ATM, ATR and DNA-PKcs in checkpoint control and resection in G 2-phase. Sci Rep 2019; 9:8255. [PMID: 31164689 PMCID: PMC6547644 DOI: 10.1038/s41598-019-44771-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/23/2019] [Indexed: 12/31/2022] Open
Abstract
Using data generated with cells exposed to ionizing-radiation (IR) in G2-phase of the cell cycle, we describe dose-dependent interactions between ATM, ATR and DNA-PKcs revealing unknown mechanistic underpinnings for two key facets of the DNA damage response: DSB end-resection and G2-checkpoint activation. At low IR-doses that induce low DSB-numbers in the genome, ATM and ATR regulate epistatically the G2-checkpoint, with ATR at the output-node, interfacing with the cell-cycle predominantly through Chk1. Strikingly, at low IR-doses, ATM and ATR epistatically regulate also resection, and inhibition of either activity fully suppresses resection. At high IR-doses that induce high DSB-numbers in the genome, the tight ATM/ATR coupling relaxes and independent outputs to G2-checkpoint and resection occur. Consequently, both kinases must be inhibited to fully suppress checkpoint activation and resection. DNA-PKcs integrates to the ATM/ATR module by regulating resection at all IR-doses, with defects in DNA-PKcs causing hyper-resection and G2-checkpoint hyper-activation. Notably, hyper-resection is absent from other c-NHEJ mutants. Thus, DNA-PKcs specifically regulates resection and adjusts the activation of the ATM/ATR module. We propose that selected DSBs are shepherd by DNA-PKcs from c-NHEJ to resection-dependent pathways for processing under the regulatory supervision of the ATM/ATR module.
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Affiliation(s)
- Emil Mladenov
- Institute of Medical Radiation Biology, University of Duisburg-Essen Medical School, 45122, Essen, Germany
| | - Xiaoxiang Fan
- Institute of Medical Radiation Biology, University of Duisburg-Essen Medical School, 45122, Essen, Germany
| | - Rositsa Dueva
- Institute of Medical Radiation Biology, University of Duisburg-Essen Medical School, 45122, Essen, Germany
| | - Aashish Soni
- Institute of Medical Radiation Biology, University of Duisburg-Essen Medical School, 45122, Essen, Germany
| | - George Iliakis
- Institute of Medical Radiation Biology, University of Duisburg-Essen Medical School, 45122, Essen, Germany.
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153
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Rodgers W, Byrum JN, Simpson DA, Hoolehan W, Rodgers KK. RAG2 localization and dynamics in the pre-B cell nucleus. PLoS One 2019; 14:e0216137. [PMID: 31075127 PMCID: PMC6510410 DOI: 10.1371/journal.pone.0216137] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 04/16/2019] [Indexed: 12/31/2022] Open
Abstract
RAG2 of the V(D)J recombinase is essential for lymphocyte development. Within the RAG2 noncore region is a plant homeodomain (PHD) that interacts with the modified histone H3K4me3, and this interaction is important for relieving inhibition of the RAG recombinase for V(D)J recombination. However, the effect of the noncore region on RAG2 localization and dynamics in cell nuclei is poorly understood. Here, we used cell imaging to measure the effect of mutating the RAG2 noncore region on properties of the full length protein. We measured GFP-labeled full length RAG2 (FL), the RAG2 core region alone (Core), and a T490A mutant in the noncore region, which has unique regulatory properties. This showed that FL, T490A, and Core localized to nuclear domains that were adjacent to DAPI-rich heterochromatin, and that contained the active chromatin marker H3K4me3. Within the RAG2-enriched regions, T490A exhibited greater colocalization with H3K4me3 than either FL or Core. Furthermore, colocalization of H3K4me3 with FL and T490A, but not Core, increased in conditions that increased H3K4me3 levels. Superresolution imaging showed H3K4me3 was distributed as puncta that RAG2 abutted, and mobility measurements showed that T490A had a significantly lower rate of diffusion within the nucleus than either FL or Core proteins. Finally, mutating Trp453 of the T490A mutant (W453A,T490A), which blocks PHD-dependent interactions with H3K4me3, abolished the T490A-mediated increased colocalization with H3K4me3 and slower mobility compared to FL. Altogether, these data show that Thr490 in the noncore region modulates RAG2 localization and dynamics in the pre-B cell nucleus, such as by affecting RAG2 interactions with H3K4me3.
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Affiliation(s)
- William Rodgers
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma, United States of America
| | - Jennifer N. Byrum
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Destiny A. Simpson
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Walker Hoolehan
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Karla K. Rodgers
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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154
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Lio CWJ, Shukla V, Samaniego-Castruita D, González-Avalos E, Chakraborty A, Yue X, Schatz DG, Ay F, Rao A. TET enzymes augment activation-induced deaminase (AID) expression via 5-hydroxymethylcytosine modifications at the Aicda superenhancer. Sci Immunol 2019; 4:eaau7523. [PMID: 31028100 PMCID: PMC6599614 DOI: 10.1126/sciimmunol.aau7523] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 03/19/2019] [Indexed: 12/15/2022]
Abstract
TET enzymes are dioxygenases that promote DNA demethylation by oxidizing the methyl group of 5-methylcytosine to 5-hydroxymethylcytosine (5hmC). Here, we report a close correspondence between 5hmC-marked regions, chromatin accessibility and enhancer activity in B cells, and a strong enrichment for consensus binding motifs for basic region-leucine zipper (bZIP) transcription factors at TET-responsive genomic regions. Functionally, Tet2 and Tet3 regulate class switch recombination (CSR) in murine B cells by enhancing expression of Aicda, which encodes the activation-induced cytidine deaminase (AID) enzyme essential for CSR. TET enzymes deposit 5hmC, facilitate DNA demethylation, and maintain chromatin accessibility at two TET-responsive enhancer elements, TetE1 and TetE2, located within a superenhancer in the Aicda locus. Our data identify the bZIP transcription factor, ATF-like (BATF) as a key transcription factor involved in TET-dependent Aicda expression. 5hmC is not deposited at TetE1 in activated Batf-deficient B cells, indicating that BATF facilitates TET recruitment to this Aicda enhancer. Our study emphasizes the importance of TET enzymes for bolstering AID expression and highlights 5hmC as an epigenetic mark that captures enhancer dynamics during cell activation.
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Affiliation(s)
- Chan-Wang J Lio
- Division of Signaling and Gene Expression, La Jolla Institute, San Diego, CA, USA.
| | - Vipul Shukla
- Division of Signaling and Gene Expression, La Jolla Institute, San Diego, CA, USA
| | | | | | | | - Xiaojing Yue
- Division of Signaling and Gene Expression, La Jolla Institute, San Diego, CA, USA
| | - David G Schatz
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Ferhat Ay
- Division of Vaccine Discovery, La Jolla Institute, San Diego, CA, USA
| | - Anjana Rao
- Division of Signaling and Gene Expression, La Jolla Institute, San Diego, CA, USA.
- Sanford Consortium for Regenerative Medicine, San Diego, CA, USA
- Department of Pharmacology, University of California, San Diego, San Diego, CA, USA
- Moores Cancer Center, University of California, San Diego, San Diego, CA, USA
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155
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156
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Abstract
Vast repertoires of unique antigen receptors are created in developing lymphocytes. The antigen receptor loci contain many variable (V), diversity (D), and joining (J) gene segments that are arrayed across very large genomic expanses and are joined to form variable-region exons. This process creates the potential for an organism to respond to large numbers of different pathogens. Here, we consider the underlying molecular mechanisms that favor some V genes for recombination prior to selection of the final antigen receptor repertoire. We discuss chromatin structures that form in antigen receptor loci to permit spatial proximity among the V, D, and J gene segments and how these relate to the generation of antigen receptor diversity.
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Affiliation(s)
- Amy L Kenter
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL, 60612-7344, USA
| | - Ann J Feeney
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, 92037, USA
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157
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Yin J, Liu M, Liu Y, Wu J, Gan T, Zhang W, Li Y, Zhou Y, Hu J. Optimizing genome editing strategy by primer-extension-mediated sequencing. Cell Discov 2019; 5:18. [PMID: 30937179 PMCID: PMC6434046 DOI: 10.1038/s41421-019-0088-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 02/27/2019] [Accepted: 02/27/2019] [Indexed: 12/26/2022] Open
Abstract
Efficient and precise genome editing is essential for clinical applications and generating animal models, which requires engineered nucleases with high editing ability while low off-target activity. Here we present a high-throughput sequencing method, primer-extension-mediated sequencing (PEM-seq), to comprehensively assess both editing ability and specificity of engineered nucleases. We showed CRISPR/Cas9-generated breaks could lead to chromosomal translocations and large deletions by PEM-seq. We also found that Cas9 nickase possessed lower off-target activity while with some loss of target cleavage ability. However, high-fidelity Cas9 variants, including both eCas9 and the new FeCas9, could significantly reduce the Cas9 off-target activity with no obvious editing retardation. Moreover, we found AcrIIA4 inhibitor could greatly reduce the activities of Cas9, but off-target loci were not so effectively suppressed as the on-target sites. Therefore, PEM-seq fully evaluating engineered nucleases could help choose better genome editing strategy at given loci than other methods detecting only off-target activity.
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Affiliation(s)
- Jianhang Yin
- 1The MOE Key Laboratory of Cell Proliferation and Differentiation, Genome Editing Research Center, School of Life Sciences, Peking University, Beijing, 100871 China.,2Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871 China
| | - Mengzhu Liu
- 1The MOE Key Laboratory of Cell Proliferation and Differentiation, Genome Editing Research Center, School of Life Sciences, Peking University, Beijing, 100871 China
| | - Yang Liu
- 1The MOE Key Laboratory of Cell Proliferation and Differentiation, Genome Editing Research Center, School of Life Sciences, Peking University, Beijing, 100871 China
| | - Jinchun Wu
- 1The MOE Key Laboratory of Cell Proliferation and Differentiation, Genome Editing Research Center, School of Life Sciences, Peking University, Beijing, 100871 China.,2Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871 China
| | - Tingting Gan
- 1The MOE Key Laboratory of Cell Proliferation and Differentiation, Genome Editing Research Center, School of Life Sciences, Peking University, Beijing, 100871 China.,2Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871 China
| | - Weiwei Zhang
- 1The MOE Key Laboratory of Cell Proliferation and Differentiation, Genome Editing Research Center, School of Life Sciences, Peking University, Beijing, 100871 China.,2Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871 China
| | - Yinghui Li
- 1The MOE Key Laboratory of Cell Proliferation and Differentiation, Genome Editing Research Center, School of Life Sciences, Peking University, Beijing, 100871 China
| | - Yaxuan Zhou
- 1The MOE Key Laboratory of Cell Proliferation and Differentiation, Genome Editing Research Center, School of Life Sciences, Peking University, Beijing, 100871 China
| | - Jiazhi Hu
- 1The MOE Key Laboratory of Cell Proliferation and Differentiation, Genome Editing Research Center, School of Life Sciences, Peking University, Beijing, 100871 China.,2Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871 China
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158
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Roch B, Abramowski V, Chaumeil J, de Villartay JP. Cernunnos/Xlf Deficiency Results in Suboptimal V(D)J Recombination and Impaired Lymphoid Development in Mice. Front Immunol 2019; 10:443. [PMID: 30923523 PMCID: PMC6426757 DOI: 10.3389/fimmu.2019.00443] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 02/19/2019] [Indexed: 12/23/2022] Open
Abstract
Xlf/Cernunnos is unique among the core factors of the non-homologous end joining (NHEJ) DNA double strand breaks (DSBs) repair pathway, in the sense that it is not essential for V(D)J recombination in vivo and in vitro. Unlike other NHEJ deficient mice showing a SCID phenotype, Xlf−/− mice present a unique immune phenotype with a moderate B- and T-cell lymphopenia, a decreased cellularity in the thymus, and a characteristic TCRα repertoire bias associated with the P53-dependent apoptosis of CD4+CD8+ DP thymocytes. Here, we thoroughly analyzed Xlf−/− mice immune phenotype and showed that it is specifically related to the DP stage but independent of the MHC-driven antigen presentation and T-cell activation during positive selection. Instead, we show that V(D)J recombination is subefficient in Xlf−/− mice in vivo, exemplified by the presence of unrepaired DSBs in the thymus. This results in a moderate developmental delay of both B- and T-lymphocytes at key V(D)J recombination dependent stages. Furthermore, subefficient V(D)J recombination waves are accumulating during TCRα rearrangement, causing the typical TCRα repertoire bias with loss of distal Vα and Jα rearrangements.
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Affiliation(s)
- Benoit Roch
- Laboratory "Genome Dynamics in the Immune System", INSERM UMR1163, Paris, France.,Institut Imagine, Université Paris Descartes Sorbonne Paris Cité, Paris, France
| | - Vincent Abramowski
- Laboratory "Genome Dynamics in the Immune System", INSERM UMR1163, Paris, France.,Institut Imagine, Université Paris Descartes Sorbonne Paris Cité, Paris, France
| | - Julie Chaumeil
- Institut Cochin, INSERM U1016, CNRS UMR8104, Université Paris-Descartes, Paris, France
| | - Jean-Pierre de Villartay
- Laboratory "Genome Dynamics in the Immune System", INSERM UMR1163, Paris, France.,Institut Imagine, Université Paris Descartes Sorbonne Paris Cité, Paris, France
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159
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Plugged into the Ku-DNA hub: The NHEJ network. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 147:62-76. [PMID: 30851288 DOI: 10.1016/j.pbiomolbio.2019.03.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 02/26/2019] [Accepted: 03/01/2019] [Indexed: 12/16/2022]
Abstract
In vertebrates, double-strand breaks in DNA are primarily repaired by Non-Homologous End-Joining (NHEJ). The ring-shaped Ku heterodimer rapidly senses and threads onto broken DNA ends forming a recruiting hub. Through protein-protein contacts eventually reinforced by protein-DNA interactions, the Ku-DNA hub attracts a series of specialized proteins with scaffolding and/or enzymatic properties. To shed light on these dynamic interplays, we review here current knowledge on proteins directly interacting with Ku and on the contact points involved, with a particular accent on the different classes of Ku-binding motifs identified in several Ku partners. An integrated structural model of the core NHEJ network at the synapsis step is proposed.
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160
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Abstract
Class switch recombination (CSR) generates isotype-switched antibodies with distinct effector functions essential for mediating effective humoral immunity. CSR is catalyzed by activation-induced deaminase (AID) that initiates DNA lesions in the evolutionarily conserved switch (S) regions at the immunoglobulin heavy chain (Igh) locus. AID-initiated DNA lesions are subsequently converted into DNA double stranded breaks (DSBs) in the S regions of Igh locus, repaired by non-homologous end-joining to effect CSR in mammalian B lymphocytes. While molecular mechanisms of CSR are well characterized, it remains less well understood how upstream signaling pathways regulate AID expression and CSR. B lymphocytes express multiple receptors including the B cell antigen receptor (BCR) and co-receptors (e.g., CD40). These receptors may share common signaling pathways or may use distinct signaling elements to regulate CSR. Here, we discuss how signals emanating from different receptors positively or negatively regulate AID expression and CSR.
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Affiliation(s)
- Zhangguo Chen
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States.
| | - Jing H Wang
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States.
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161
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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: 25] [Impact Index Per Article: 5.0] [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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162
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Bouwman BAM, Crosetto N. Endogenous DNA Double-Strand Breaks during DNA Transactions: Emerging Insights and Methods for Genome-Wide Profiling. Genes (Basel) 2018; 9:E632. [PMID: 30558210 PMCID: PMC6316733 DOI: 10.3390/genes9120632] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/11/2018] [Accepted: 12/12/2018] [Indexed: 02/07/2023] Open
Abstract
DNA double-strand breaks (DSBs) jeopardize genome integrity and can-when repaired unfaithfully-give rise to structural rearrangements associated with cancer. Exogenous agents such as ionizing radiation or chemotherapy can invoke DSBs, but a vast amount of breakage arises during vital endogenous DNA transactions, such as replication and transcription. Additionally, chromatin looping involved in 3D genome organization and gene regulation is increasingly recognized as a possible contributor to DSB events. In this review, we first discuss insights into the mechanisms of endogenous DSB formation, showcasing the trade-off between essential DNA transactions and the intrinsic challenges that these processes impose on genomic integrity. In the second part, we highlight emerging methods for genome-wide profiling of DSBs, and discuss future directions of research that will help advance our understanding of genome-wide DSB formation and repair.
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Affiliation(s)
- Britta A M Bouwman
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17165 Stockholm, Sweden.
| | - Nicola Crosetto
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17165 Stockholm, Sweden.
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163
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Kuri-Magaña H, Collado-Torres L, Jaffe AE, Valdovinos-Torres H, Ovilla-Muñoz M, Téllez-Sosa J, Bonifaz LC, Martínez-Barnetche J. Non-coding Class Switch Recombination-Related Transcription in Human Normal and Pathological Immune Responses. Front Immunol 2018; 9:2679. [PMID: 30519242 PMCID: PMC6260145 DOI: 10.3389/fimmu.2018.02679] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Accepted: 10/30/2018] [Indexed: 12/22/2022] Open
Abstract
Antibody class switch recombination (CSR) to IgG, IgA, or IgE is a hallmark of adaptive immunity, allowing antibody function diversification beyond IgM. CSR involves a deletion of the IgM/IgD constant region genes placing a new acceptor Constant gene, downstream of the VDJH exon. CSR depends on non-coding (CSRnc) transcription of donor Iμ and acceptor IH exons, located 5′ upstream of each CH coding gene. Although, our knowledge of the role of CSRnc transcription has advanced greatly, its extension and importance in healthy and diseased humans is scarce. We analyzed CSRnc transcription in 70,603 publicly available RNA-seq samples, including GTEx, TCGA, and the Sequence Read Archive using recount2, an online resource consisting of normalized RNA-seq gene and exon counts, as well as, coverage BigWig files that can be programmatically accessed through R. CSRnc transcription was validated with a qRT-PCR assay for Iμ, Iγ3, and Iγ1 in humans in response to vaccination. We mapped IH transcription for the human IGH locus, including the less understood IGHD gene. CSRnc transcription was restricted to B cells and is widely distributed in normal adult tissues, but predominant in blood, spleen, MALT-containing tissues, visceral adipose tissue and some so-called “immune privileged” tissues. However, significant Iγ4 expression was found even in non-lymphoid fetal tissues. CSRnc expression in cancer tissues mimicked the expression of their normal counterparts, with notable pattern changes in some common cancer subsets. CSRnc transcription in tumors appears to result from tumor infiltration by B cells, since CSRnc transcription was not detected in corresponding tumor-derived immortal cell lines. Additionally, significantly increased Iδ transcription in ileal mucosa in Crohn's disease with ulceration was found. In conclusion, CSRnc transcription occurs in multiple anatomical locations beyond classical secondary lymphoid organs, representing a potentially useful marker of effector B cell responses in normal and pathological immune responses. The pattern of IH exon expression may reveal clues of the local immune response (i.e., cytokine milieu) in health and disease. This is a great example of how the public recount2 data can be used to further our understanding of transcription, including regions outside the known transcriptome.
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Affiliation(s)
- Helena Kuri-Magaña
- Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Mexico.,Programa de Doctorado en Ciencias Biomédicas, Universidad Nacional Autónoma de Mexico, Mexico City, Mexico
| | - Leonardo Collado-Torres
- Lieber Institute for Brain Development, Baltimore, MD, United States.,Center for Computational Biology, Johns Hopkins University, Baltimore, MD, United States
| | - Andrew E Jaffe
- Lieber Institute for Brain Development, Baltimore, MD, United States.,Center for Computational Biology, Johns Hopkins University, Baltimore, MD, United States.,Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States.,Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Humberto Valdovinos-Torres
- Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Mexico
| | - Marbella Ovilla-Muñoz
- Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Mexico
| | - Juan Téllez-Sosa
- Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Mexico
| | - Laura C Bonifaz
- Unidad de Investigación Medica en Inmunoquímica, Hospital de Especialidades, Centro Medico Nacional Siglo XXI, Instituto Mexicano del Seguro Social (IMSS), Mexico City, Mexico
| | - Jesús Martínez-Barnetche
- Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Mexico
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164
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The Role for the DSB Response Pathway in Regulating Chromosome Translocations. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1044:65-87. [PMID: 29956292 DOI: 10.1007/978-981-13-0593-1_6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In response to DNA double strand breaks (DSB), mammalian cells activate the DNA Damage Response (DDR), a network of factors that coordinate their detection, signaling and repair. Central to this network is the ATM kinase and its substrates at chromatin surrounding DSBs H2AX, MDC1 and 53BP1. In humans, germline inactivation of ATM causes Ataxia Telangiectasia (A-T), an autosomal recessive syndrome of increased proneness to hematological malignancies driven by clonal chromosomal translocations. Studies of cancers arising in A-T patients and in genetically engineered mouse models (GEMM) deficient for ATM and its substrates have revealed complex, multilayered roles for ATM in translocation suppression and identified functional redundancies between ATM and its substrates in this context. "Programmed" DSBs at antigen receptor loci in developing lymphocytes employ ubiquitous DDR factors for signaling and repair and have been particularly useful for mechanistic studies because they are region-specific and can be monitored in vitro and in vivo. In this context, murine thymocytes deficient for ATM recapitulate the molecular events that lead to transformation in T cells from A-T patients and provide a widely used model to study the mechanisms that suppress RAG recombinase-dependent translocations. Similarly, analyses of the fate of Activation induced Cytidine Deaminase (AID)-dependent DSBs during mature B cell Class Switch Recombination (CSR) have defined the genetic requirements for end-joining and translocation suppression in this setting. Moreover, a unique role for 53BP1 in the promotion of synapsis of distant DSBs has emerged from these studies.
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165
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Jiao J, Jin Y, Zheng M, Zhang H, Yuan M, Lv Z, Odhiambo W, Yu X, Zhang P, Li C, Ma Y, Ji Y. AID and TET2 co-operation modulates FANCA expression by active demethylation in diffuse large B cell lymphoma. Clin Exp Immunol 2018; 195:190-201. [PMID: 30357811 DOI: 10.1111/cei.13227] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2018] [Indexed: 01/06/2023] Open
Abstract
Diffuse large B cell lymphoma (DLBCL) is traced to a mature B malignance carrying abnormal activation-induced cytidine deaminase (AID) expression. AID activity initially focuses on deamination of cytidine to uracil to generate somatic hypermutation and class-switch recombination of the immunoglobulin (Ig), but recently it has been implicated in DNA demethylation of genes required for B cell development and proliferation in the germinal centre (GC). However, whether AID activity on mutation or demethylation of genes involves oncogenesis of DLBCL has not been well characterized. Our data demonstrate that the proto-oncogene Fanconi anaemia complementation group A (FANCA) is highly expressed in DLBCL patients and cell lines, respectively. AID recruits demethylation enzyme ten eleven translocation family member (TET2) to bind the FANCA promoter. As a result, FANCA is demethylated and its expression increases in DLBCL. On the basis of our findings, we have developed a new therapeutic strategy to significantly inhibit DLBCL cell growth by combination of the proteasome inhibitor bortezomib with AID and TET2 depletion. These findings support a novel mechanism that AID has a crucial role in active demethylation for oncogene activation in DLBCL.
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Affiliation(s)
- J Jiao
- Department of Pathogenic Biology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Centre, Xi'an, China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an, China
| | - Y Jin
- Department of Pathology, the 2nd Affiliated hospital of Medical College, Xi'an Jiaotong University, Xi'an, China
| | - M Zheng
- Department of Pathogenic Biology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Centre, Xi'an, China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an, China
| | - H Zhang
- Department of Pathogenic Biology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Centre, Xi'an, China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an, China
| | - M Yuan
- Department of Pathogenic Biology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Centre, Xi'an, China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an, China
| | - Z Lv
- Department of Pathogenic Biology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Centre, Xi'an, China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an, China
| | - W Odhiambo
- Department of Pathogenic Biology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Centre, Xi'an, China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an, China
| | - X Yu
- Department of Pathogenic Biology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Centre, Xi'an, China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an, China
| | - P Zhang
- Department of Pathogenic Biology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Centre, Xi'an, China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an, China
| | - C Li
- Department of Pathogenic Biology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Centre, Xi'an, China
| | - Y Ma
- Department of Pathogenic Biology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Centre, Xi'an, China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an, China
| | - Y Ji
- Department of Pathogenic Biology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Centre, Xi'an, China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an, China
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166
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Sharma AK, Hendzel MJ. The relationship between histone posttranslational modification and DNA damage signaling and repair. Int J Radiat Biol 2018; 95:382-393. [PMID: 30252564 DOI: 10.1080/09553002.2018.1516911] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE The cellular response to DNA damage occurs in the context of an organized chromatin environment in order to maintain genome integrity. Immediately after DNA damage, an array of histone modifications are induced to relieve the physical constraints of the chromatin environment, mark the site as damaged, and function as a platform for the assembly of mediator and effector proteins of DNA damage response signaling pathway. Changes in chromatin structure in the vicinity of the DNA double-strand break (DSB) facilitates the efficient initiation of the DNA damage signaling cascade. Failure of induction of DNA damage responsive histone modifications may lead to genome instability and cancer. Here we will discuss our current understanding of the DNA damage responsive histone modifications and their role in DNA repair as well as their implications for genome stability. We further discuss recent studies which highlight not only how histone modification has involved in the signaling and remodeling at the DSB but also how it influences the DNA repair pathway choice. CONCLUSIONS Histone modifications pattern alter during the induction of DNA DSBs induction as well as during the repair and recovery phase of DNA damage response. It will be interesting to understand more precisely, how DSBs within chromatin are repaired by HR and NHEJ. The emergence of proteomic and genomic technologies in combination with advanced microscopy and imaging methods will help in better understanding the role of chromatin environment in the regulation of genome stability.
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Affiliation(s)
- Ajit K Sharma
- a Departments of Cell Biology and Oncology, Faculty of Medicine and Dentistry , University of Alberta , Edmonton , Canada
| | - Michael J Hendzel
- a Departments of Cell Biology and Oncology, Faculty of Medicine and Dentistry , University of Alberta , Edmonton , Canada
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167
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Kalita CA, Brown CD, Freiman A, Isherwood J, Wen X, Pique-Regi R, Luca F. High-throughput characterization of genetic effects on DNA-protein binding and gene transcription. Genome Res 2018; 28:1701-1708. [PMID: 30254052 PMCID: PMC6211638 DOI: 10.1101/gr.237354.118] [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: 03/26/2018] [Accepted: 09/20/2018] [Indexed: 12/29/2022]
Abstract
Many variants associated with complex traits are in noncoding regions and contribute to phenotypes by disrupting regulatory sequences. To characterize these variants, we developed a streamlined protocol for a high-throughput reporter assay, Biallelic Targeted STARR-seq (BiT-STARR-seq), that identifies allele-specific expression (ASE) while accounting for PCR duplicates through unique molecular identifiers. We tested 75,501 oligos (43,500 SNPs) and identified 2720 SNPs with significant ASE (FDR < 10%). To validate disruption of binding as one of the mechanisms underlying ASE, we developed a new high-throughput allele-specific binding assay for NFKB1. We identified 2684 SNPs with allele-specific binding (ASB) (FDR < 10%); 256 of these SNPs also had ASE (OR = 1.97, P-value = 0.0006). Of variants associated with complex traits, 1531 resulted in ASE, and 1662 showed ASB. For example, we characterized that the Crohn's disease risk variant for rs3810936 increases NFKB1 binding and results in altered gene expression.
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Affiliation(s)
- Cynthia A Kalita
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan 48202, USA
| | - Christopher D Brown
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Andrew Freiman
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan 48202, USA
| | - Jenna Isherwood
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan 48202, USA
| | - Xiaoquan Wen
- Department of Biostatistics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Roger Pique-Regi
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan 48202, USA.,Department of Obstetrics and Gynecology, Wayne State University, Detroit, Michigan 48202, USA
| | - Francesca Luca
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan 48202, USA.,Department of Obstetrics and Gynecology, Wayne State University, Detroit, Michigan 48202, USA
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168
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Khamlichi AA, Feil R. Parallels between Mammalian Mechanisms of Monoallelic Gene Expression. Trends Genet 2018; 34:954-971. [PMID: 30217559 DOI: 10.1016/j.tig.2018.08.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 08/06/2018] [Accepted: 08/16/2018] [Indexed: 02/06/2023]
Abstract
Different types of monoallelic gene expression are present in mammals, some of which are highly flexible, whereas others are more rigid. These include allelic exclusion at antigen receptor loci, the expression of olfactory receptor genes, genomic imprinting, X-chromosome inactivation, and random monoallelic expression (MAE). Although these processes play diverse biological roles, and arose through different selective pressures, the underlying epigenetic mechanisms show striking resemblances. Regulatory transcriptional events are important in all systems, particularly in the specification of MAE. Combined with comparative studies between species, this suggests that the different MAE systems found in mammals may have evolved from analogous ancestral processes.
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Affiliation(s)
- Ahmed Amine Khamlichi
- Institute of Pharmacology and Structural Biology (IPBS), Centre National de la Recherche Scientifique (CNRS) and Paul Sabatier University (UPS), 205 route de Narbonne, 31077 Toulouse, France.
| | - Robert Feil
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS and the University of Montpellier, 1919 route de Mende, 34293 Montpellier, France.
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169
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Guiding a mutator in antibody diversification. Cell Res 2018; 28:963-964. [PMID: 30171189 DOI: 10.1038/s41422-018-0085-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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170
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Arazoe T, Kondo A, Nishida K. Targeted Nucleotide Editing Technologies for Microbial Metabolic Engineering. Biotechnol J 2018; 13:e1700596. [PMID: 29862665 DOI: 10.1002/biot.201700596] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 05/15/2018] [Indexed: 12/31/2022]
Abstract
Since the emergence of programmable RNA-guided nucleases based on clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) systems, genome editing technologies have become a simplified and versatile tool for genome editing in various organisms and cell types. Although genome editing enables efficient genome manipulations, such as gene disruptions, gene knockins, and chromosomal translocations via DNA double-strand break (DSB) repair in eukaryotes, DSBs induced by the CRISPR/Cas system are lethal or severely toxic to many microorganisms. Therefore, in many prokaryotes, including industrially useful microbes, the CRISPR/Cas system is often used as a negative selection component in combination with recombineering or other related strategies. Novel and revolutionary technologies have been recently developed to re-write targeted nucleotides (C:G to T:A and A:T to G:C) without DSBs and donor DNA templates. These technologies rely on the recruitment of deaminases at specific target loci using the nuclease-deficient CRISPR/Cas system. Here, the authors review and compare CRISPR-based genome editing, current base editing platforms and their spectra. The authors discuss how these technologies can be applied in various aspects of microbial metabolic engineering to overcome barriers to cellular regulation in prokaryotes.
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Affiliation(s)
- Takayuki Arazoe
- Department of Applied Biological Science, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan
| | - Akihiko Kondo
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Keiji Nishida
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
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171
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Lin SG, Ba Z, Alt FW, Zhang Y. RAG Chromatin Scanning During V(D)J Recombination and Chromatin Loop Extrusion are Related Processes. Adv Immunol 2018; 139:93-135. [PMID: 30249335 DOI: 10.1016/bs.ai.2018.07.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
An effective adaptive immune system depends on the ability of developing B and T cells to generate diverse immunoglobulin (Ig) and T cell receptor repertoires, respectively. Such diversity is achieved through a programmed somatic recombination process whereby germline V, D, and J segments of antigen receptor loci are assembled to form the variable region V(D)J exons of Ig and TCRs. Studies of this process, termed V(D)J recombination, have provided key insights into our understanding of a variety of general gene regulatory and DNA repair processes over the last several decades. V(D)J recombination is initiated by the RAG endonuclease which generates DNA double-stranded breaks at the borders of V, D, and J segments. In this review, we cover recent work that has elucidated RAG structure and work that revealed that RAG has a novel chromatin scanning activity, likely mediated by chromatin loop extrusion, that contributes to its ability to locate V, D, J gene segment substrates within large chromosomal loop domains bounded by CTCF-binding elements (CBEs). This latter function, coupled with the role CBE-based chromatin loop domains and subdomains within them play in focusing V(D)J recombination activity within antigen receptor loci, provide mechanistic explanations for long-standing questions regarding V(D)J segment usage diversification and in limiting potentially deleterious off-target RAG-initiated recombination events genome-wide. This review will focus mainly on studies of the mouse Ig heavy chain locus, but the principles described also apply to other Ig loci and to TCR loci in mice and humans.
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Affiliation(s)
- Sherry G Lin
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, United States
| | - Zhaoqing Ba
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, United States
| | - Frederick W Alt
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, United States.
| | - Yu Zhang
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, United States
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172
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Chen J, Cai Z, Bai M, Yu X, Zhang C, Cao C, Hu X, Wang L, Su R, Wang D, Wang L, Yao Y, Ye R, Hou B, Yu Y, Yu S, Li J, Xue Y. The RNA-binding protein ROD1/PTBP3 cotranscriptionally defines AID-loading sites to mediate antibody class switch in mammalian genomes. Cell Res 2018; 28:981-995. [PMID: 30143796 PMCID: PMC6170407 DOI: 10.1038/s41422-018-0076-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Revised: 07/08/2018] [Accepted: 07/16/2018] [Indexed: 02/06/2023] Open
Abstract
Activation-induced cytidine deaminase (AID) mediates class switching by binding to a small fraction of single-stranded DNA (ssDNA) to diversify the antibody repertoire. The precise mechanism for highly selective AID targeting in the genome has remained elusive. Here, we report an RNA-binding protein, ROD1 (also known as PTBP3), that is both required and sufficient to define AID-binding sites genome-wide in activated B cells. ROD1 interacts with AID via an ultraconserved loop, which proves to be critical for the recruitment of AID to ssDNA using bi-directionally transcribed nascent RNAs as stepping stones. Strikingly, AID-specific mutations identified in human patients with hyper-IgM syndrome type 2 (HIGM2) completely disrupt the AID interacting surface with ROD1, thereby abolishing the recruitment of AID to immunoglobulin (Ig) loci. Together, our results suggest that bi-directionally transcribed RNA traps the RNA-binding protein ROD1, which serves as a guiding system for AID to load onto specific genomic loci to induce DNA rearrangement during immune responses.
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Affiliation(s)
- Juan Chen
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Zhaokui Cai
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Meizhu Bai
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, 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, 320 Yueyang Road, 200031, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, 201210, Shanghai, China
| | - Xiaohua Yu
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Chao Zhang
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Changchang Cao
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Xihao Hu
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Lei Wang
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.,College of Life Sciences, Institute for Conservation and Utilization of Agro-bioresources in Dabie Mountains, Xinyang Normal University, 464000, Xinyang, China
| | - Ruibao Su
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Di Wang
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Lei Wang
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Yingpeng Yao
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, People's Republic of China
| | - Rong Ye
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Baidong Hou
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Yang Yu
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Shuyang Yu
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, People's Republic of China
| | - Jinsong Li
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, 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, 320 Yueyang Road, 200031, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, 201210, Shanghai, China
| | - Yuanchao Xue
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China. .,University of Chinese Academy of Sciences, 100049, Beijing, China.
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173
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Alt FW, Schwer B. DNA double-strand breaks as drivers of neural genomic change, function, and disease. DNA Repair (Amst) 2018; 71:158-163. [PMID: 30195640 DOI: 10.1016/j.dnarep.2018.08.019] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Early work from about two decades ago implicated DNA double-strand break (DSB) formation and repair in neuronal development. Findings emerging from recent studies of DSBs in proliferating neural progenitors and in mature, non-dividing neurons suggest important roles of DSBs in brain physiology, aging, cancer, psychiatric and neurodegenerative disorders. We provide an overview of some findings and speculate on what may lie ahead.
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Affiliation(s)
- Frederick W Alt
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Department of Genetics, and Department of Pediatrics, Harvard Medical School, Boston, MA 02115, United States.
| | - Bjoern Schwer
- Department of Neurological Surgery and Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA 94158, United States.
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174
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Jain S, Ba Z, Zhang Y, Dai HQ, Alt FW. CTCF-Binding Elements Mediate Accessibility of RAG Substrates During Chromatin Scanning. Cell 2018; 174:102-116.e14. [PMID: 29804837 PMCID: PMC6026039 DOI: 10.1016/j.cell.2018.04.035] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/07/2018] [Accepted: 04/25/2018] [Indexed: 01/06/2023]
Abstract
RAG endonuclease initiates antibody heavy chain variable region exon assembly from V, D, and J segments within a chromosomal V(D)J recombination center (RC) by cleaving between paired gene segments and flanking recombination signal sequences (RSSs). The IGCR1 control region promotes DJH intermediate formation by isolating Ds, JHs, and RCs from upstream VHs in a chromatin loop anchored by CTCF-binding elements (CBEs). How VHs access the DJHRC for VH to DJH rearrangement was unknown. We report that CBEs immediately downstream of frequently rearranged VH-RSSs increase recombination potential of their associated VH far beyond that provided by RSSs alone. This CBE activity becomes particularly striking upon IGCR1 inactivation, which allows RAG, likely via loop extrusion, to linearly scan chromatin far upstream. VH-associated CBEs stabilize interactions of D-proximal VHs first encountered by the DJHRC during linear RAG scanning and thereby promote dominant rearrangement of these VHs by an unanticipated chromatin accessibility-enhancing CBE function.
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MESH Headings
- Animals
- CCCTC-Binding Factor/metabolism
- Cell Line
- Chromatin/metabolism
- DNA, Intergenic/genetics
- DNA, Intergenic/metabolism
- DNA-Binding Proteins/deficiency
- DNA-Binding Proteins/genetics
- Homeodomain Proteins/metabolism
- Immunoglobulin Heavy Chains/genetics
- Immunoglobulin Heavy Chains/metabolism
- Immunoglobulin Variable Region/genetics
- Immunoglobulin Variable Region/metabolism
- Mice
- Mice, Inbred C57BL
- Models, Molecular
- Mutagenesis
- Protein Sorting Signals
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/metabolism
- V(D)J Recombination
- RNA, Guide, CRISPR-Cas Systems
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Affiliation(s)
- Suvi Jain
- Howard Hughes Medical Institute; Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Zhaoqing Ba
- Howard Hughes Medical Institute; Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Yu Zhang
- Howard Hughes Medical Institute; Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Hai-Qiang Dai
- Howard Hughes Medical Institute; Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Frederick W Alt
- Howard Hughes Medical Institute; Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
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175
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George VC, Ansari SA, Chelakkot VS, Chelakkot AL, Chelakkot C, Menon V, Ramadan W, Ethiraj KR, El-Awady R, Mantso T, Mitsiogianni M, Panagiotidis MI, Dellaire G, Vasantha Rupasinghe HP. DNA-dependent protein kinase: Epigenetic alterations and the role in genomic stability of cancer. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2018; 780:92-105. [PMID: 31395353 DOI: 10.1016/j.mrrev.2018.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 06/13/2018] [Indexed: 12/28/2022]
Abstract
DNA-dependent protein kinase (DNA-PK), a member of phosphatidylinositol-kinase family, is a key protein in mammalian DNA double-strand break (DSB) repair that helps to maintain genomic integrity. DNA-PK also plays a central role in immune cell development and protects telomerase during cellular aging. Epigenetic deregulation due to endogenous and exogenous factors may affect the normal function of DNA-PK, which in turn could impair DNA repair and contribute to genomic instability. Recent studies implicate a role for epigenetics in the regulation of DNA-PK expression in normal and cancer cells, which may impact cancer progression and metastasis as well as provide opportunities for treatment and use of DNA-PK as a novel cancer biomarker. In addition, several small molecules and biological agents have been recently identified that can inhibit DNA-PK function or expression, and thus hold promise for cancer treatments. This review discusses the impact of epigenetic alterations and the expression of DNA-PK in relation to the DNA repair mechanisms with a focus on its differential levels in normal and cancer cells.
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Affiliation(s)
- Vazhappilly Cijo George
- Department of Plant, Food, and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, NS, Canada; Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Shabbir Ahmed Ansari
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, TX, United States
| | - Vipin Shankar Chelakkot
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | | | - Chaithanya Chelakkot
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Varsha Menon
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Wafaa Ramadan
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates; College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | | | - Raafat El-Awady
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates; College of Pharmacy, University of Sharjah, Sharjah, United Arab Emirates; Cancer Biology Department, National Cancer Institute and College of Medicine, Cairo University, Cairo, Egypt
| | - Theodora Mantso
- Department of Plant, Food, and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, NS, Canada; Department of Applied Sciences, Faculty of Health & Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Melina Mitsiogianni
- Department of Plant, Food, and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, NS, Canada; Department of Applied Sciences, Faculty of Health & Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Mihalis I Panagiotidis
- Department of Applied Sciences, Faculty of Health & Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Graham Dellaire
- Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - H P Vasantha Rupasinghe
- Department of Plant, Food, and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, NS, Canada; Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada.
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176
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PROMIDISα: A T-cell receptor α signature associated with immunodeficiencies caused by V(D)J recombination defects. J Allergy Clin Immunol 2018; 143:325-334.e2. [PMID: 29906526 DOI: 10.1016/j.jaci.2018.05.028] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 04/17/2018] [Accepted: 05/25/2018] [Indexed: 01/08/2023]
Abstract
BACKGROUND V(D)J recombination ensures the diversity of the adaptive immune system. Although its complete defect causes severe combined immunodeficiency (ie, T-B- severe combined immunodeficiency), its suboptimal activity is associated with a broad spectrum of immune manifestations, such as late-onset combined immunodeficiency and autoimmunity. The earliest molecular diagnosis of these patients is required to adopt the best therapy strategy, particularly when it involves a myeloablative conditioning regimen for hematopoietic stem cell transplantation. OBJECTIVE We aimed at developing biomarkers based on analysis of the T-cell receptor (TCR) α repertoire to assist in the diagnosis of patients with primary immunodeficiencies with V(D)J recombination and DNA repair deficiencies. METHODS We used flow cytometric (fluorescence-activated cell sorting) analysis to quantify TCR-Vα7.2-expressing T lymphocytes in peripheral blood and developed PROMIDISα, a multiplex RT-PCR/next-generation sequencing assay, to evaluate a subset of the TCRα repertoire in T lymphocytes. RESULTS The combined fluorescence-activated cell sorting and PROMIDISα analyses revealed specific signatures in patients with V(D)J recombination-defective primary immunodeficiencies or ataxia telangiectasia/Nijmegen breakage syndromes. CONCLUSION Analysis of the TCRα repertoire is particularly appropriate in a prospective way to identify patients with partial immune defects caused by suboptimal V(D)J recombination activity, a DNA repair defect, or both. It also constitutes a valuable tool for the retrospective in vivo functional validation of variants identified through exome or panel sequencing. Its broader implementation might be of interest to assist early diagnosis of patients presenting with hypomorphic DNA repair defects inclined to experience acute toxicity during prehematopoietic stem cell transplantation conditioning.
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177
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Pichugin A, Iarovaia OV, Gavrilov A, Sklyar I, Barinova N, Barinov A, Ivashkin E, Caron G, Aoufouchi S, Razin SV, Fest T, Lipinski M, Vassetzky YS. The IGH locus relocalizes to a "recombination compartment" in the perinucleolar region of differentiating B-lymphocytes. Oncotarget 2018; 8:40079-40089. [PMID: 28445143 PMCID: PMC5522243 DOI: 10.18632/oncotarget.16941] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 03/29/2017] [Indexed: 12/22/2022] Open
Abstract
The immunoglobulin heavy chain (IGH) gene loci are subject to specific recombination events during B-cell differentiation including somatic hypermutation and class switch recombination which mark the end of immunoglobulin gene maturation in germinal centers of secondary lymph nodes. These two events rely on the activity of activation-induced cytidine deaminase (AID) which requires DNA double strand breaks be created, a potential danger to the cell. Applying 3D-fluorescence in situ hybridization coupled with immunofluorescence staining to a previously described experimental system recapitulating normal B-cell differentiation ex vivo, we have kinetically analyzed the radial positioning of the two IGH gene loci as well as their proximity with the nucleolus, heterochromatin and γH2AX foci. Our observations are consistent with the proposal that these IGH gene rearrangements take place in a specific perinucleolar “recombination compartment” where AID could be sequestered thus limiting the extent of its potentially deleterious off-target effects.
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Affiliation(s)
- Andrey Pichugin
- UMR8126, CNRS, Université Paris Sud Paris Saclay, Institut Gustave Roussy, Villejuif, France.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France.,Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
| | - Olga V Iarovaia
- UMR8126, CNRS, Université Paris Sud Paris Saclay, Institut Gustave Roussy, Villejuif, France.,Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France
| | - Alexey Gavrilov
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France
| | - Ilya Sklyar
- UMR8126, CNRS, Université Paris Sud Paris Saclay, Institut Gustave Roussy, Villejuif, France.,Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France
| | - Natalja Barinova
- UMR8126, CNRS, Université Paris Sud Paris Saclay, Institut Gustave Roussy, Villejuif, France.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France
| | - Aleksandr Barinov
- LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France
| | - Evgeny Ivashkin
- UMR8126, CNRS, Université Paris Sud Paris Saclay, Institut Gustave Roussy, Villejuif, France.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France.,Department of Experimental Neurocytology, Research Center of Neurology, Branch of Brain Research, Moscow, Russia
| | - Gersende Caron
- INSERM U1236, CHU de Rennes, Université Rennes 1, Rennes, France
| | - Said Aoufouchi
- UMR8200 CNRS, Université Paris-Sud, Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Sergey V Razin
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France.,Moscow State University, Moscow, Russia
| | - Thierry Fest
- INSERM U1236, CHU de Rennes, Université Rennes 1, Rennes, France
| | - Marc Lipinski
- UMR8126, CNRS, Université Paris Sud Paris Saclay, Institut Gustave Roussy, Villejuif, France.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France
| | - Yegor S Vassetzky
- UMR8126, CNRS, Université Paris Sud Paris Saclay, Institut Gustave Roussy, Villejuif, France.,LIA 1066, Laboratoire Franco-Russe de Recherche en Oncologie, Villejuif, France.,Moscow State University, Moscow, Russia
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178
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Nicolas L, Cols M, Choi JE, Chaudhuri J, Vuong B. Generating and repairing genetically programmed DNA breaks during immunoglobulin class switch recombination. F1000Res 2018; 7:458. [PMID: 29744038 PMCID: PMC5904731 DOI: 10.12688/f1000research.13247.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/09/2018] [Indexed: 01/03/2023] Open
Abstract
Adaptive immune responses require the generation of a diverse repertoire of immunoglobulins (Igs) that can recognize and neutralize a seemingly infinite number of antigens. V(D)J recombination creates the primary Ig repertoire, which subsequently is modified by somatic hypermutation (SHM) and class switch recombination (CSR). SHM promotes Ig affinity maturation whereas CSR alters the effector function of the Ig. Both SHM and CSR require activation-induced cytidine deaminase (AID) to produce dU:dG mismatches in the Ig locus that are transformed into untemplated mutations in variable coding segments during SHM or DNA double-strand breaks (DSBs) in switch regions during CSR. Within the Ig locus, DNA repair pathways are diverted from their canonical role in maintaining genomic integrity to permit AID-directed mutation and deletion of gene coding segments. Recently identified proteins, genes, and regulatory networks have provided new insights into the temporally and spatially coordinated molecular interactions that control the formation and repair of DSBs within the Ig locus. Unravelling the genetic program that allows B cells to selectively alter the Ig coding regions while protecting non-Ig genes from DNA damage advances our understanding of the molecular processes that maintain genomic integrity as well as humoral immunity.
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Affiliation(s)
- Laura Nicolas
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Montserrat Cols
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jee Eun Choi
- Department of Biology, The City College of New York and The Graduate Center of The City University of New York, New York, NY, USA
| | - Jayanta Chaudhuri
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Bao Vuong
- Department of Biology, The City College of New York and The Graduate Center of The City University of New York, New York, NY, USA
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179
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Turcotte CA, Sloat SA, Rigothi JA, Rosenkranse E, Northrup AL, Andrews NP, Checchi PM. Maintenance of Genome Integrity by Mi2 Homologs CHD-3 and LET-418 in Caenorhabditis elegans. Genetics 2018; 208:991-1007. [PMID: 29339410 PMCID: PMC5844346 DOI: 10.1534/genetics.118.300686] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 01/10/2018] [Indexed: 02/06/2023] Open
Abstract
Meiotic recombination depends upon the tightly coordinated regulation of chromosome dynamics and is essential for the production of haploid gametes. Central to this process is the formation and repair of meiotic double-stranded breaks (DSBs), which must take place within the constraints of a specialized chromatin architecture. Here, we demonstrate a role for the nucleosome remodeling and deacetylase (NuRD) complex in orchestrating meiotic chromosome dynamics in Caenorhabditis elegans Our data reveal that the conserved Mi2 homologs Chromodomain helicase DNA-binding protein (CHD-3) and its paralog LET-418 facilitate meiotic progression by ensuring faithful repair of DSBs through homologous recombination. We discovered that loss of either CHD-3 or LET-418 results in elevated p53-dependent germ line apoptosis, which relies on the activation of the conserved checkpoint kinase CHK-1 Consistent with these findings, chd-3 and let-418 mutants produce a reduced number of offspring, indicating a role for Mi2 in forming viable gametes. When Mi2 function is compromised, persisting recombination intermediates are detected in late pachytene nuclei, indicating a failure in the timely repair of DSBs. Intriguingly, our data indicate that in Mi2 mutant germ lines, a subset of DSBs are repaired by nonhomologous end joining, which manifests as chromosomal fusions. We find that meiotic defects are exacerbated in Mi2 mutants lacking CKU-80, as evidenced by increased recombination intermediates, corpses, and defects in chromosomal integrity. Taken together, our findings support a model wherein the C. elegans Mi2 complex maintains genomic integrity through reinforcement of a chromatin landscape suitable for homology-driven repair mechanisms.
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Affiliation(s)
| | - Solomon A Sloat
- Department of Biology, Marist College, Poughkeepsie, New York 12601
| | - Julia A Rigothi
- Department of Biology, Marist College, Poughkeepsie, New York 12601
| | | | | | | | - Paula M Checchi
- Department of Biology, Marist College, Poughkeepsie, New York 12601
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180
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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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181
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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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182
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Actionable perturbations of damage responses by TCL1/ATM and epigenetic lesions form the basis of T-PLL. Nat Commun 2018; 9:697. [PMID: 29449575 PMCID: PMC5814445 DOI: 10.1038/s41467-017-02688-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 12/19/2017] [Indexed: 12/20/2022] Open
Abstract
T-cell prolymphocytic leukemia (T-PLL) is a rare and poor-prognostic mature T-cell malignancy. Here we integrated large-scale profiling data of alterations in gene expression, allelic copy number (CN), and nucleotide sequences in 111 well-characterized patients. Besides prominent signatures of T-cell activation and prevalent clonal variants, we also identify novel hot-spots for CN variability, fusion molecules, alternative transcripts, and progression-associated dynamics. The overall lesional spectrum of T-PLL is mainly annotated to axes of DNA damage responses, T-cell receptor/cytokine signaling, and histone modulation. We formulate a multi-dimensional model of T-PLL pathogenesis centered around a unique combination of TCL1 overexpression with damaging ATM aberrations as initiating core lesions. The effects imposed by TCL1 cooperate with compromised ATM toward a leukemogenic phenotype of impaired DNA damage processing. Dysfunctional ATM appears inefficient in alleviating elevated redox burdens and telomere attrition and in evoking a p53-dependent apoptotic response to genotoxic insults. As non-genotoxic strategies, synergistic combinations of p53 reactivators and deacetylase inhibitors reinstate such cell death execution. T-cell prolymphocytic leukemia (T-PLL) is a rare malignancy with a poor prognosis. Here, the authors investigate the genomic landscape, gene expression profiles and functional mechanisms in 111 patients, highlighting TCL1 overexpression and ATM aberrations as core lesions which co-operate to impair DNA damage processing.
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183
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Three classes of recurrent DNA break clusters in brain progenitors identified by 3D proximity-based break joining assay. Proc Natl Acad Sci U S A 2018; 115:1919-1924. [PMID: 29432181 DOI: 10.1073/pnas.1719907115] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
We recently discovered 27 recurrent DNA double-strand break (DSB) clusters (RDCs) in mouse neural stem/progenitor cells (NSPCs). Most RDCs occurred across long, late-replicating RDC genes and were found only after mild inhibition of DNA replication. RDC genes share intriguing characteristics, including encoding surface proteins that organize brain architecture and neuronal junctions, and are genetically implicated in neuropsychiatric disorders and/or cancers. RDC identification relies on high-throughput genome-wide translocation sequencing (HTGTS), which maps recurrent DSBs based on their translocation to "bait" DSBs in specific chromosomal locations. Cellular heterogeneity in 3D genome organization allowed unequivocal identification of RDCs on 14 different chromosomes using HTGTS baits on three mouse chromosomes. Additional candidate RDCs were also implicated, however, suggesting that some RDCs were missed. To more completely identify RDCs, we exploited our finding that joining of two DSBs occurs more frequently if they lie on the same cis chromosome. Thus, we used CRISPR/Cas9 to introduce specific DSBs into each mouse chromosome in NSPCs that were used as bait for HTGTS libraries. This analysis confirmed all 27 previously identified RDCs and identified many new ones. NSPC RDCs fall into three groups based on length, organization, transcription level, and replication timing of genes within them. While mostly less robust, the largest group of newly defined RDCs share many intriguing characteristics with the original 27. Our findings also revealed RDCs in NSPCs in the absence of induced replication stress, and support the idea that the latter treatment augments an already active endogenous process.
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184
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DNA double-strand break response factors influence end-joining features of IgH class switch and general translocation junctions. Proc Natl Acad Sci U S A 2018; 115:762-767. [PMID: 29311308 DOI: 10.1073/pnas.1719988115] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ig heavy chain (IgH) class switch recombination (CSR) in B lymphocytes switches IgH constant regions to change antibody functions. CSR is initiated by DNA double-strand breaks (DSBs) within a donor IgH switch (S) region and a downstream acceptor S region. CSR is completed by fusing donor and acceptor S region DSB ends by classical nonhomologous end-joining (C-NHEJ) and, in its absence, by alternative end-joining that is more biased to use longer junctional microhomologies (MHs). Deficiency for DSB response (DSBR) factors, including ataxia telangiectasia-mutated (ATM) and 53BP1, variably impair CSR end-joining, with 53BP1 deficiency having the greatest impact. However, studies of potential impact of DSBR factor deficiencies on MH-mediated CSR end-joining have been technically limited. We now use a robust DSB joining assay to elucidate impacts of deficiencies for DSBR factors on CSR and chromosomal translocation junctions in primary mouse B cells and CH12F3 B-lymphoma cells. Compared with wild-type, CSR and c-myc to S region translocation junctions in the absence of 53BP1, and, to a lesser extent, other DSBR factors, have increased MH utilization; indeed, 53BP1-deficient MH profiles resemble those associated with C-NHEJ deficiency. However, translocation junctions between c-myc DSB and general DSBs genome-wide are not MH-biased in ATM-deficient versus wild-type CH12F3 cells and are less biased in 53BP1- and C-NHEJ-deficient cells than CSR junctions or c-myc to S region translocation junctions. We discuss potential roles of DSBR factors in suppressing increased MH-mediated DSB end-joining and features of S regions that may render their DSBs prone to MH-biased end-joining in the absence of DSBR factors.
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185
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Gothe HJ, Minneker V, Roukos V. Dynamics of Double-Strand Breaks: Implications for the Formation of Chromosome Translocations. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1044:27-38. [PMID: 29956289 DOI: 10.1007/978-981-13-0593-1_3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Illegitimate joining of chromosome breaks can lead to the formation of chromosome translocations, a catastrophic type of genome rearrangements that often plays key roles in tumorigenesis. Emerging evidence suggests that the mobility of broken DNA loci can be an important determinant in partner search and clustering of individual breaks, events that can influence translocation frequency. We summarize here the recent literature on the mechanisms that regulate chromatin movement, focusing on studies exploring the motion properties of double-strand breaks in the context of chromatin, the functional consequences for DNA repair, and the formation of chromosome fusions.
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186
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Liu X, Meng FL. Generation of Genomic Alteration from Cytidine Deamination. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1044:49-64. [DOI: 10.1007/978-981-13-0593-1_5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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187
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Processing-Challenges Generated by Clusters of DNA Double-Strand Breaks Underpin Increased Effectiveness of High-LET Radiation and Chromothripsis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1044:149-168. [DOI: 10.1007/978-981-13-0593-1_10] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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188
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Bordignon V, Di Domenico EG, Trento E, D'Agosto G, Cavallo I, Pontone M, Pimpinelli F, Mariani L, Ensoli F. How Human Papillomavirus Replication and Immune Evasion Strategies Take Advantage of the Host DNA Damage Repair Machinery. Viruses 2017; 9:v9120390. [PMID: 29257060 PMCID: PMC5744164 DOI: 10.3390/v9120390] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 12/14/2017] [Accepted: 12/16/2017] [Indexed: 12/11/2022] Open
Abstract
The DNA damage response (DDR) is a complex signalling network activated when DNA is altered by intrinsic or extrinsic agents. DDR plays important roles in genome stability and cell cycle regulation, as well as in tumour transformation. Viruses have evolved successful life cycle strategies in order to ensure a chronic persistence in the host, virtually avoiding systemic sequelae and death. This process promotes the periodic shedding of large amounts of infectious particles to maintain a virus reservoir in individual hosts, while allowing virus spreading within the community. To achieve such a successful lifestyle, the human papilloma virus (HPV) needs to escape the host defence systems. The key to understanding how this is achieved is in the virus replication process that provides by itself an evasion mechanism by inhibiting and delaying the host immune response against the viral infection. Numerous studies have demonstrated that HPV exploits both the ataxia-telangiectasia mutated (ATM) and ataxia-telangiectasia and rad3-related (ATR) DDR pathways to replicate its genome and maintain a persistent infection by downregulating the innate and cell-mediated immunity. This review outlines how HPV interacts with the ATM- and ATR-dependent DDR machinery during the viral life cycle to create an environment favourable to viral replication, and how the interaction with the signal transducers and activators of transcription (STAT) protein family and the deregulation of the Janus kinase (JAK)-STAT pathways may impact the expression of interferon-inducible genes and the innate immune responses.
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Affiliation(s)
- Valentina Bordignon
- Clinical Pathology and Microbiology Unit, San Gallicano Dermatology Institute, IRCCS, IFO, Via Elio Chianesi 53, 00144 Rome, Italy.
| | - Enea Gino Di Domenico
- Clinical Pathology and Microbiology Unit, San Gallicano Dermatology Institute, IRCCS, IFO, Via Elio Chianesi 53, 00144 Rome, Italy.
| | - Elisabetta Trento
- Clinical Pathology and Microbiology Unit, San Gallicano Dermatology Institute, IRCCS, IFO, Via Elio Chianesi 53, 00144 Rome, Italy.
| | - Giovanna D'Agosto
- Clinical Pathology and Microbiology Unit, San Gallicano Dermatology Institute, IRCCS, IFO, Via Elio Chianesi 53, 00144 Rome, Italy.
| | - Ilaria Cavallo
- Clinical Pathology and Microbiology Unit, San Gallicano Dermatology Institute, IRCCS, IFO, Via Elio Chianesi 53, 00144 Rome, Italy.
| | - Martina Pontone
- Clinical Pathology and Microbiology Unit, San Gallicano Dermatology Institute, IRCCS, IFO, Via Elio Chianesi 53, 00144 Rome, Italy.
| | - Fulvia Pimpinelli
- Clinical Pathology and Microbiology Unit, San Gallicano Dermatology Institute, IRCCS, IFO, Via Elio Chianesi 53, 00144 Rome, Italy.
| | - Luciano Mariani
- HPV Unit, Department of Gynaecologic Oncology, National Cancer Institute Regina Elena, IRCCS, IFO, Via Elio Chianesi 53, 00144 Rome, Italy.
| | - Fabrizio Ensoli
- Clinical Pathology and Microbiology Unit, San Gallicano Dermatology Institute, IRCCS, IFO, Via Elio Chianesi 53, 00144 Rome, Italy.
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189
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High-throughput sequencing of the immune repertoire in oncology: Applications for clinical diagnosis, monitoring, and immunotherapies. Cancer Lett 2017; 416:42-56. [PMID: 29247824 DOI: 10.1016/j.canlet.2017.12.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 12/11/2017] [Accepted: 12/11/2017] [Indexed: 12/21/2022]
Abstract
The diagnostic, monitoring and therapeutic options for cancers currently remain limited. These limitations represent a large threat to human health. Adaptive immunity, which is dependent on diverse repertoires of B cell receptors (BCRs) and T cell receptors (TCRs), plays a critical role in the anti-tumor immune response. Modulation and surveillance of adaptive immunity has become a powerful weapon to combat cancers. Recently, the high-throughput sequencing of immune repertoire (HTS-IR) technology, which provides a robust tool for deep sequencing repertoires of BCRs or TCRs, has been applied in the development of tumor biomarkers and immunotherapeutics for cancers. This review will first provide an overview of the advancement of HTS-IR technology at the population-cell and single-cell levels. It will then provide a current summary of the applications of HTS-IR technology in the diagnosis and monitoring of minimal residual disease (MRD), focusing on immune reconstitution after the treatment of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in B/T-cell malignancies, and the precise detection of tumor-infiltrating lymphocytes (TILs) in non-B/T-cell malignancies. Finally, current advances of HTS-IR technology in cancer immunotherapeutic applications, such as therapeutic antibodies, CAR-T cell based-adoptive immunotherapies, and neoantigen-specific TCR-T cell-based adoptive immunotherapies, will be introduced.
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190
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Shapiro JA. Living Organisms Author Their Read-Write Genomes in Evolution. BIOLOGY 2017; 6:E42. [PMID: 29211049 PMCID: PMC5745447 DOI: 10.3390/biology6040042] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 11/17/2017] [Accepted: 11/28/2017] [Indexed: 12/18/2022]
Abstract
Evolutionary variations generating phenotypic adaptations and novel taxa resulted from complex cellular activities altering genome content and expression: (i) Symbiogenetic cell mergers producing the mitochondrion-bearing ancestor of eukaryotes and chloroplast-bearing ancestors of photosynthetic eukaryotes; (ii) interspecific hybridizations and genome doublings generating new species and adaptive radiations of higher plants and animals; and, (iii) interspecific horizontal DNA transfer encoding virtually all of the cellular functions between organisms and their viruses in all domains of life. Consequently, assuming that evolutionary processes occur in isolated genomes of individual species has become an unrealistic abstraction. Adaptive variations also involved natural genetic engineering of mobile DNA elements to rewire regulatory networks. In the most highly evolved organisms, biological complexity scales with "non-coding" DNA content more closely than with protein-coding capacity. Coincidentally, we have learned how so-called "non-coding" RNAs that are rich in repetitive mobile DNA sequences are key regulators of complex phenotypes. Both biotic and abiotic ecological challenges serve as triggers for episodes of elevated genome change. The intersections of cell activities, biosphere interactions, horizontal DNA transfers, and non-random Read-Write genome modifications by natural genetic engineering provide a rich molecular and biological foundation for understanding how ecological disruptions can stimulate productive, often abrupt, evolutionary transformations.
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Affiliation(s)
- James A Shapiro
- Department of Biochemistry and Molecular Biology, University of Chicago GCIS W123B, 979 E. 57th Street, Chicago, IL 60637, USA.
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191
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Hamilton PB, Rolshausen G, Uren Webster TM, Tyler CR. Adaptive capabilities and fitness consequences associated with pollution exposure in fish. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0042. [PMID: 27920387 PMCID: PMC5182438 DOI: 10.1098/rstb.2016.0042] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2016] [Indexed: 12/22/2022] Open
Abstract
Many fish populations are exposed to harmful levels of chemical pollution and selection pressures associated with these exposures have led to the evolution of tolerance. Our understanding of the physiological basis for these adaptations is limited, but they are likely to include processes involved with the absorption, distribution, metabolism and/or excretion of the target chemical. Other potential adaptive mechanisms include enhancements in antioxidant responses, an increased capacity for DNA and/or tissue repair and alterations to the life cycle of fish that enable earlier reproduction. Analysis of single-nucleotide polymorphism frequencies has shown that tolerance to hydrocarbon pollutants in both marine and estuarine fish species involves alteration in the expression of the xenobiotic metabolism enzyme CYP1A. In this review, we present novel data showing also that variants of the CYP1A gene have been under selection in guppies living in Trinidadian rivers heavily polluted with crude oil. Potential costs associated with these adaptations could reduce fitness in unpolluted water conditions. Integrating knowledge of local adaptation to pollution is an important future consideration in conservation practices such as for successful restocking, and improving connectivity within river systems.This article is part of the themed issue 'Human influences on evolution, and the ecological and societal consequences'.
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Affiliation(s)
- Patrick B Hamilton
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK
| | - Gregor Rolshausen
- Senckenberg Biodiversity and Climate Research Centre (BiK-F), Senckenberganlage 25, 60325 Frankfurt am Main, Germany
| | - Tamsyn M Uren Webster
- Department of Biosciences, Swansea University, Wallace Building, Swansea SA2 8PP, UK
| | - Charles R Tyler
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK
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192
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Histone methyltransferase MMSET promotes AID-mediated DNA breaks at the donor switch region during class switch recombination. Proc Natl Acad Sci U S A 2017; 114:E10560-E10567. [PMID: 29158395 DOI: 10.1073/pnas.1701366114] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In B cells, Ig class switch recombination (CSR) is initiated by activation-induced cytidine deaminase (AID), the activity of which leads to DNA double-strand breaks (DSBs) within IgH switch (S) regions. Preferential targeting of AID-mediated DSBs to S sequences is critical for allowing diversification of antibody functions, while minimizing potential off-target oncogenic events. Here, we used gene targeted inactivation of histone methyltransferase (HMT) multiple myeloma SET domain (MMSET) in mouse B cells and the CH12F3 cell line to explore its role in CSR. We find that deletion of MMSET-II, the isoform containing the catalytic SET domain, inhibits CSR without affecting either IgH germline transcription or joining of DSBs within S regions by classical nonhomologous end joining (C-NHEJ). Instead, we find that MMSET-II inactivation leads to decreased AID recruitment and DSBs at the upstream donor Sμ region. Our findings suggest a role for the HMT MMSET in promoting AID-mediated DNA breaks during CSR.
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193
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Mu Y, Zelazowska MA, McBride KM. Phosphorylation promotes activation-induced cytidine deaminase activity at the Myc oncogene. J Exp Med 2017; 214:3543-3552. [PMID: 29122947 PMCID: PMC5716038 DOI: 10.1084/jem.20170468] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 08/16/2017] [Accepted: 09/26/2017] [Indexed: 12/31/2022] Open
Abstract
The molecular mechanisms that regulate AID mutator activity at off-target genes are not well characterized. Mu et al. show AID phosphorylation dynamically controls activity at Myc and other sites. Pharmacological induction of AID phosphorylation leads to increased mutations, double strand breakss and translocations. Activation-induced cytidine deaminase (AID) is a mutator enzyme that targets immunoglobulin (Ig) genes to initiate antibody somatic hypermutation (SHM) and class switch recombination (CSR). Off-target AID association also occurs, which causes oncogenic mutations and chromosome rearrangements. However, AID occupancy does not directly correlate with DNA damage, suggesting that factors beyond AID association contribute to mutation targeting. CSR and SHM are regulated by phosphorylation on AID serine38 (pS38), but the role of pS38 in off-target activity has not been evaluated. We determined that lithium, a clinically used therapeutic, induced high AID pS38 levels. Using lithium and an AID-S38 phospho mutant, we compared the role of pS38 in AID activity at the Ig switch region and off-target Myc gene. We found that deficient pS38 abated AID chromatin association and CSR but not mutation at Myc. Enhanced pS38 elevated Myc translocation and mutation frequency but not CSR or Ig switch region mutation. Thus, AID activity can be differentially targeted by phosphorylation to induce oncogenic lesions.
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Affiliation(s)
- Yunxiang Mu
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX
| | - Monika A Zelazowska
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX
| | - Kevin M McBride
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX
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194
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Abe K, Takamatsu T, Sato T. Mechanism of bacterial gene rearrangement: SprA-catalyzed precise DNA recombination and its directionality control by SprB ensure the gene rearrangement and stable expression of spsM during sporulation in Bacillus subtilis. Nucleic Acids Res 2017; 45:6669-6683. [PMID: 28535266 PMCID: PMC5499854 DOI: 10.1093/nar/gkx466] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/12/2017] [Indexed: 12/17/2022] Open
Abstract
A sporulation-specific gene, spsM, is disrupted by an active prophage, SPβ, in the genome of Bacillus subtilis. SPβ excision is required for two critical steps: the onset of the phage lytic cycle and the reconstitution of the spsM-coding frame during sporulation. Our in vitro study demonstrated that SprA, a serine-type integrase, catalyzed integration and excision reactions between attP of SPβ and attB within spsM, while SprB, a recombination directionality factor, was necessary only for the excision between attL and attR in the SPβ lysogenic chromosome. DNA recombination occurred at the center of the short inverted repeat motif in the unique conserved 16 bp sequence among the att sites (5΄-ACAGATAA/AGCTGTAT-3΄; slash, breakpoint; underlines, inverted repeat), where SprA produced the 3΄-overhanging AA and TT dinucleotides for rejoining the DNA ends through base-pairing. Electrophoretic mobility shift assay showed that SprB promoted synapsis of SprA subunits bound to the two target sites during excision but impaired it during integration. In vivo data demonstrated that sprB expression that lasts until the late stage of sporulation is crucial for stable expression of reconstituted spsM without reintegration of the SPβ prophage. These results present a deeper understanding of the mechanism of the prophage-mediated bacterial gene regulatory system.
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Affiliation(s)
- Kimihiro Abe
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Tokyo 184-0003, Japan
| | - Takuo Takamatsu
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 184-8584, Japan
| | - Tsutomu Sato
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Tokyo 184-0003, Japan.,Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 184-8584, Japan
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195
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Feng YL, Xiang JF, Liu SC, Guo T, Yan GF, Feng Y, Kong N, Li HD, Huang Y, Lin H, Cai XJ, Xie AY. H2AX facilitates classical non-homologous end joining at the expense of limited nucleotide loss at repair junctions. Nucleic Acids Res 2017; 45:10614-10633. [PMID: 28977657 PMCID: PMC5737864 DOI: 10.1093/nar/gkx715] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 08/04/2017] [Indexed: 12/20/2022] Open
Abstract
Phosphorylated histone H2AX, termed 'γH2AX', mediates the chromatin response to DNA double strand breaks (DSBs) in mammalian cells. H2AX deficiency increases the numbers of unrepaired DSBs and translocations, which are partly associated with defects in non-homologous end joining (NHEJ) and contributing to genomic instability in cancer. However, the role of γH2AX in NHEJ of general DSBs has yet to be clearly defined. Here, we showed that despite little effect on overall NHEJ efficiency, H2AX deficiency causes a surprising bias towards accurate NHEJ and shorter deletions in NHEJ products. By analyzing CRISPR/Cas9-induced NHEJ and by using a new reporter for mutagenic NHEJ, we found that γH2AX, along with its interacting protein MDC1, is required for efficient classical NHEJ (C-NHEJ) but with short deletions and insertions. Epistasis analysis revealed that ataxia telangiectasia mutated (ATM) and the chromatin remodeling complex Tip60/TRRAP/P400 are essential for this H2AX function. Taken together, these data suggest that a subset of DSBs may require γH2AX-mediated short-range nucleosome repositioning around the breaks to facilitate C-NHEJ with loss of a few extra nucleotides at NHEJ junctions. This may prevent outcomes such as non-repair and translocations, which are generally more destabilizing to genomes than short deletions and insertions from local NHEJ.
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Affiliation(s)
- Yi-Li Feng
- Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, Zhejiang 310019, China.,Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China
| | - Ji-Feng Xiang
- Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, Zhejiang 310019, China.,Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China
| | - Si-Cheng Liu
- Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, Zhejiang 310019, China.,Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China
| | - Tao Guo
- Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, Zhejiang 310019, China.,Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China
| | - Guo-Fang Yan
- Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, Zhejiang 310019, China.,Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China
| | - Ye Feng
- Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, Zhejiang 310019, China.,Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China
| | - Na Kong
- Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, Zhejiang 310019, China.,Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China
| | - Hao-Dan Li
- Shurui Tech Ltd, Hangzhou, Zhejiang 310005, China
| | - Yang Huang
- Shurui Tech Ltd, Hangzhou, Zhejiang 310005, China
| | - Hui Lin
- Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, Zhejiang 310019, China
| | - Xiu-Jun Cai
- Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, Zhejiang 310019, China
| | - An-Yong Xie
- Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, Zhejiang 310019, China.,Institute of Translational Medicine, Zhejiang University, Hangzhou, Zhejiang 310029, China
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196
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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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197
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Zaki-Dizaji M, Akrami SM, Abolhassani H, Rezaei N, Aghamohammadi A. Ataxia telangiectasia syndrome: moonlighting ATM. Expert Rev Clin Immunol 2017; 13:1155-1172. [PMID: 29034753 DOI: 10.1080/1744666x.2017.1392856] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Ataxia-telangiectasia (A-T) a multisystem disorder primarily characterized by cerebellar degeneration, telangiectasia, immunodeficiency, cancer susceptibility and radiation sensitivity. Identification of the gene defective in this syndrome, ataxia-telangiectasia mutated gene (ATM), and further characterization of the disorder together with a greater insight into the function of the ATM protein have expanded our knowledge about the molecular pathogenesis of this disease. Area covered: In this review, we have attempted to summarize the different roles of ATM signaling that have provided new insights into the diverse clinical phenotypes exhibited by A-T patients. Expert commentary: ATM, in addition to DNA repair response, is involved in many cytoplasmic roles that explain diverse phenotypes of A-T patients. It seems accumulation of DNA damage, persistent DNA damage response signaling, and chronic oxidative stress are the main players in the pathogenesis of this disease.
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Affiliation(s)
- Majid Zaki-Dizaji
- a Department of Medical Genetics, School of Medicine , Tehran University of Medical Sciences , Tehran , Iran.,b Research Center for Immunodeficiencies, Children's Medical Center , Tehran University of Medical Science , Tehran , Iran
| | - Seyed Mohammad Akrami
- a Department of Medical Genetics, School of Medicine , Tehran University of Medical Sciences , Tehran , Iran
| | - Hassan Abolhassani
- b Research Center for Immunodeficiencies, Children's Medical Center , Tehran University of Medical Science , Tehran , Iran.,c Division of Clinical Immunology, Department of Laboratory Medicine , Karolinska Institute at Karolinska University Hospital Huddinge , Stockholm , Sweden.,d Primary Immunodeficiency Diseases Network (PIDNet ), Universal Scientific Education and Research Network (USERN) , Stockholm , Sweden
| | - Nima Rezaei
- b Research Center for Immunodeficiencies, Children's Medical Center , Tehran University of Medical Science , Tehran , Iran.,e Department of Immunology and Biology, School of Medicine , Tehran University of Medical Sciences , Tehran , Iran.,f Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA) , Universal Scientific Education and Research Network (USERN) , Tehran , Iran
| | - Asghar Aghamohammadi
- b Research Center for Immunodeficiencies, Children's Medical Center , Tehran University of Medical Science , Tehran , Iran
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198
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Abstract
Genetic abnormalities are present in all tumor types, although the frequency and type can vary. Chromosome abnormalities include highly aberrant structures, particularly chromothriptic chromosomes. The generation of massive sequencing data has illuminated the scope of the mutational burden in cancer genomes, identifying patterns of mutations (mutation signatures), which have the potential to shed light on the relatedness and etiologies of cancers and impact therapy response. Some mutation patterns are clearly attributable to disruptions in pathways that maintain genomic integrity. Here we review recent advances in our understanding of genetic changes occurring in cancers and the roles of genome maintenance pathways.
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Affiliation(s)
- Elizabeth M Kass
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Mary Ellen Moynahan
- Department of Medicine, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.
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199
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Verkoczy L, Alt FW, Tian M. Human Ig knockin mice to study the development and regulation of HIV-1 broadly neutralizing antibodies. Immunol Rev 2017; 275:89-107. [PMID: 28133799 DOI: 10.1111/imr.12505] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A major challenge for HIV-1 vaccine research is developing a successful immunization approach for inducing broadly neutralizing antibodies (bnAbs). A key shortcoming in meeting this challenge has been the lack of animal models capable of identifying impediments limiting bnAb induction and ranking vaccine strategies for their ability to promote bnAb development. Since 2010, immunoglobulin knockin (KI) technology, involving inserting functional rearranged human variable exons into the mouse IgH and IgL loci has been used to express bnAbs in mice. This approach has allowed immune tolerance mechanisms limiting bnAb production to be elucidated and strategies to overcome such limitations to be evaluated. From these studies, along with the wealth of knowledge afforded by analyses of recombinant Ig-based bnAb structures, it became apparent that key functional features of bnAbs often are problematic for their elicitation in mice by classic vaccine paradigms, necessitating more iterative testing of new vaccine concepts. In this regard, bnAb KI models expressing deduced precursor V(D)J rearrangements of mature bnAbs or unrearranged germline V, D, J segments (that can be assembled into variable region exons that encode bnAb precursors), have been engineered to evaluate novel immunogens/regimens for effectiveness in driving bnAb responses. One promising approach emerging from such studies is the ability of sequentially administered, modified immunogens (designed to bind progressively more mature bnAb precursors) to initiate affinity maturation. Here, we review insights gained from bnAb KI studies regarding the regulation and induction of bnAbs, and discuss new Ig KI methodologies to manipulate the production and/or expression of bnAbs in vivo, to further facilitate vaccine-guided bnAb induction studies.
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Affiliation(s)
- Laurent Verkoczy
- Departments of Medicine and Pathology, Duke University Human Vaccine Institute, Duke University School of Medicine, Durham, NC, USA
| | - Frederick W Alt
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital and Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Ming Tian
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital and Department of Genetics, Harvard Medical School, Boston, MA, USA
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200
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Hsu E. Assembly and Expression of Shark Ig Genes. THE JOURNAL OF IMMUNOLOGY 2017; 196:3517-23. [PMID: 27183649 DOI: 10.4049/jimmunol.1600164] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 03/04/2016] [Indexed: 11/19/2022]
Abstract
Sharks are modern descendants of the earliest vertebrates possessing Ig superfamily receptor-based adaptive immunity. They respond to immunogen with Abs that, upon boosting, appear more rapidly and show affinity maturation. Specific Abs and immunological memory imply that Ab diversification and clonal selection exist in cartilaginous fish. Shark Ag receptors are generated through V(D)J recombination, and because it is a mechanism known to generate autoreactive receptors, this implies that shark lymphocytes undergo selection. In the mouse, the ∼2.8-Mb IgH and IgL loci require long-range, differential activation of component parts for V(D)J recombination, allelic exclusion, and receptor editing. These processes, including class switching, evolved with and appear inseparable from the complex locus organization. In contrast, shark Igs are encoded by 100-200 autonomously rearranging miniloci. This review describes how the shark primary Ab repertoire is generated in the absence of structural features considered essential in mammalian Ig gene assembly and expression.
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Affiliation(s)
- Ellen Hsu
- Department of Physiology and Pharmacology, The State University of New York Health Science Center at Brooklyn, Brooklyn, NY 11203
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