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Glynn RA, Hayer KE, Bassing CH. ATM-dependent Phosphorylation of Nemo SQ Motifs Is Dispensable for Nemo-mediated Gene Expression Changes in Response to DNA Double-Strand Breaks. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 213:628-640. [PMID: 39007641 PMCID: PMC11348802 DOI: 10.4049/jimmunol.2300139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 06/25/2024] [Indexed: 07/16/2024]
Abstract
In response to DNA double-strand breaks (DSBs), the ATM kinase activates NF-κB factors to stimulate gene expression changes that promote survival and allow time for cells to repair damage. In cell lines, ATM can activate NF-κB transcription factors via two independent, convergent mechanisms. One is ATM-mediated phosphorylation of nuclear NF-κB essential modulator (Nemo) protein, which leads to monoubiquitylation and export of Nemo to the cytoplasm where it engages the IκB kinase (IKK) complex to activate NF-κB. Another is DSB-triggered migration of ATM into the cytoplasm, where it promotes monoubiquitylation of Nemo and the resulting IKK-mediated activation of NF-κB. ATM has many other functions in the DSB response beyond activation of NF-κB, and Nemo activates NF-κB downstream of diverse stimuli, including developmental or proinflammatory stimuli such as LPSs. To elucidate the in vivo role of DSB-induced, ATM-dependent changes in expression of NF-κB-responsive genes, we generated mice expressing phosphomutant Nemo protein lacking consensus SQ sites for phosphorylation by ATM or related kinases. We demonstrate that these mice are viable/healthy and fertile and exhibit overall normal B and T lymphocyte development. Moreover, treatment of their B lineage cells with LPS induces normal NF-κB-regulated gene expression changes. Furthermore, in marked contrast to results from a pre-B cell line, primary B lineage cells expressing phosphomutant Nemo treated with the genotoxic drug etoposide induce normal ATM- and Nemo-dependent changes in expression of NF-κB-regulated genes. Our data demonstrate that ATM-dependent phosphorylation of Nemo SQ motifs in vivo is dispensable for DSB-signaled changes in expression of NF-κB-regulated genes.
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Affiliation(s)
- Rebecca A. Glynn
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Katharina E. Hayer
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Biomedical Engineering Doctoral Degree Program, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, 19104
- Department of Biomedical and Health Informatics, Children’s Hospital of Philadelphia, Perelman School of Medicine, Philadelphia, PA, 19104
| | - Craig H. Bassing
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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2
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Culberson EJ, Shields KC, Glynn RA, Allyn BM, Hayer KE, Bassing CH. The Cyclin D3 Protein Enforces Monogenic TCRβ Expression by Mediating TCRβ Protein-Signaled Feedback Inhibition of Vβ Recombination. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 212:534-540. [PMID: 38117277 PMCID: PMC10872516 DOI: 10.4049/jimmunol.2300623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 11/27/2023] [Indexed: 12/21/2023]
Abstract
In jawed vertebrates, adaptive immunity depends on the process of V(D)J recombination creating vast numbers of T and B lymphocytes that each expresses unique Ag receptors of uniform specificity. The asynchronous initiation of V-to-(D)J rearrangement between alleles and the resulting protein from one allele signaling feedback inhibition of V recombination on the other allele ensures homogeneous receptor specificity of individual cells. Upon productive Vβ-to-DβJβ rearrangements in noncycling double-negative thymocytes, TCRβ protein signals induction of the cyclin D3 protein to accelerate cell cycle entry, thereby driving proliferative expansion of developing αβ T cells. Through undetermined mechanisms, the inactivation of cyclin D3 in mice causes an increased frequency of αβ T cells that express TCRβ proteins from both alleles, producing lymphocytes of heterogeneous specificities. To determine how cyclin D3 enforces monogenic TCRβ expression, we used our mouse lines with enhanced rearrangement of specific Vβ segments due to replacement of their poor-quality recombination signal sequence (RSS) DNA elements with a better RSS. We show that cyclin D3 inactivation in these mice elevates the frequencies of αβ T cells that display proteins from RSS-augmented Vβ segments on both alleles. By assaying mature αβ T cells, we find that cyclin D3 deficiency increases the levels of Vβ rearrangements that occur within developing thymocytes. Our data demonstrate that a component of the cell cycle machinery mediates TCRβ protein-signaled feedback inhibition in thymocytes to achieve monogenic TCRβ expression and resulting uniform specificity of individual αβ T cells.
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Affiliation(s)
- Erica J. Culberson
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Kymberle C. Shields
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Rebecca A. Glynn
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Brittney M. Allyn
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Katharina E. Hayer
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Biomedical Engineering Doctoral Degree Program, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104
- Department of Biomedical and Health Informatics, Children’s Hospital of Philadelphia, Perelman School of Medicine, Philadelphia, PA 19104
| | - Craig H. Bassing
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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3
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Wu GS, Culberson EJ, Allyn BM, Bassing CH. Poor-Quality Vβ Recombination Signal Sequences and the DNA Damage Response ATM Kinase Collaborate to Establish TCRβ Gene Repertoire and Allelic Exclusion. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:2583-2592. [PMID: 35534211 PMCID: PMC9133172 DOI: 10.4049/jimmunol.2100489] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 03/23/2022] [Indexed: 06/03/2023]
Abstract
The monoallelic expression (allelic exclusion) of diverse lymphocyte Ag receptor genes enables specific immune responses. Allelic exclusion is achieved by asynchronous initiation of V(D)J recombination between alleles and protein encoded by successful rearrangement on the first allele signaling permanent inhibition of V rearrangement on the other allele. The ATM kinase that guides DNA repair and transiently suppresses V(D)J recombination also helps impose allelic exclusion through undetermined mechanisms. At the TCRβ locus, one Vβ gene segment (V31) rearranges only by inversion, whereas all other Vβ segments rearrange by deletion except for rare cases in which they rearrange through inversion following V31 rearrangement. The poor-quality recombination signal sequences (RSSs) of V31 and V2 help establish TCRβ gene repertoire and allelic exclusion by stochastically limiting initiation of Vβ rearrangements before TCRβ protein-signaled permanent silencing of Vβ recombination. We show in this study in mice that ATM functions with these RSSs and the weak V1 RSS to shape TCRβ gene repertoire by restricting their Vβ segments from initiating recombination and hindering aberrant nonfunctional Vβ recombination products, especially during inversional V31 rearrangements. We find that ATM collaborates with the V1 and V2 RSSs to help enforce allelic exclusion by facilitating competition between alleles for initiation and functional completion of rearrangements of these Vβ segments. Our data demonstrate that the fundamental genetic DNA elements that underlie inefficient Vβ recombination cooperate with ATM-mediated rapid DNA damage responses to help establish diversity and allelic exclusion of TCRβ genes.
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Affiliation(s)
- Glendon S Wu
- Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA; and
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Erica J Culberson
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Brittney M Allyn
- Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA; and
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Craig H Bassing
- Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA; and
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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4
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Glynn RA, Bassing CH. Nemo-Dependent, ATM-Mediated Signals from RAG DNA Breaks at Igk Feedback Inhibit V κ Recombination to Enforce Igκ Allelic Exclusion. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:371-383. [PMID: 34965965 PMCID: PMC8756740 DOI: 10.4049/jimmunol.2100696] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 11/01/2021] [Indexed: 01/17/2023]
Abstract
Monoallelic AgR gene expression underlies specific adaptive immune responses. AgR allelic exclusion is achieved by sequential initiation of V(D)J recombination between alleles and resultant protein from one allele signaling to prevent recombination of the other. The ATM kinase, a regulator of the DNA double-strand break (DSB) response, helps enforce allelic exclusion through undetermined mechanisms. ATM promotes repair of RAG1/RAG2 (RAG) endonuclease-induced DSBs and transduces signals from RAG DSBs during Igk gene rearrangement on one allele to transiently inhibit RAG1 protein expression, Igk accessibility, and RAG cleavage of the other allele. Yet, the relative contributions of ATM functions in DSB repair versus signaling to enforce AgR allelic exclusion remain undetermined. In this study, we demonstrate that inactivation in mouse pre-B cells of the NF-κB essential modulator (Nemo) protein, an effector of ATM signaling, diminishes RAG DSB-triggered repression of Rag1/Rag2 transcription and Igk accessibility but does not result in aberrant repair of RAG DSBs like ATM inactivation. We show that Nemo deficiency increases simultaneous biallelic Igk cleavage in pre-B cells and raises the frequency of B cells expressing Igκ proteins from both alleles. In contrast, the incidence of biallelic Igκ expression is not elevated by inactivation of the SpiC transcriptional repressor, which is induced by RAG DSBs in an ATM-dependent manner and suppresses Igk accessibility. Thus, we conclude that Nemo-dependent, ATM-mediated DNA damage signals enforce Igκ allelic exclusion by orchestrating transient repression of RAG expression and feedback inhibition of additional Igk rearrangements in response to RAG cleavage on one Igk allele.
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Affiliation(s)
- Rebecca A. Glynn
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104,Department of Pathology and Laboratory Medicine, Children’s Hospital of Pennsylvania, Philadelphia, PA 19104
| | - Craig H. Bassing
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104,Department of Pathology and Laboratory Medicine, Children’s Hospital of Pennsylvania, Philadelphia, PA 19104,Corresponding Author: Craig H. Bassing, Ph.D., Children’s Hospital of Philadelphia, 4054 Colket Translational Research Building, 3501 Civic Center Blvd., Philadelphia, PA 19104, 267-426-0311,
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5
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Krangel MS. RSSs set the odds for exclusion. J Exp Med 2021; 217:152017. [PMID: 32793983 PMCID: PMC7478726 DOI: 10.1084/jem.20200831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this issue of JEM, Wu et al. (https://doi.org/10.1084/jem.20200412) provide new insights into allelic exclusion. They demonstrate that Vβ-to-DβJβ rearrangement occurs stochastically on two competing Tcrb alleles, with suboptimal Vβ recombination signal sequences limiting synchronous rearrangements and essential for allelic exclusion.
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Affiliation(s)
- Michael S Krangel
- Department of Immunology, Duke University Medical Center, Durham, NC
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6
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Abstract
The assembly of T cell receptor (TCR) and immunoglobulin (Ig) genes by V(D)J recombination generates the antigen receptor (AgR) diversity that is vital for adaptive immunity. At most AgR loci, V(D)J recombination is regulated so that only one allele assembles a functional gene, ensuring that nearly every T and B cell expresses a single type, or specificity, of AgR. The genomic organizations of some AgR loci permit the assembly and expression of two distinct genes on each allele; however, this is prevented by undetermined mechanisms. We show that the poor qualities of recombination signal sequences (RSSs) flanking Vβ gene segments suppress the assembly and expression of two distinct TCRβ genes from a single allele. Our data demonstrate that an intrinsic genetic mechanism that stochastically limits Vβ recombination efficiency governs monogenic TCRβ expression, thereby restraining the expression of multiple AgRs on αβ T cells.
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7
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Balseanu AT, Grigore M, Pinosanu LR, Slevin M, Hermann DM, Glavan D, Popa-Wagner A. Electric Stimulation of Neurogenesis Improves Behavioral Recovery After Focal Ischemia in Aged Rats. Front Neurosci 2020; 14:732. [PMID: 32742258 PMCID: PMC7365235 DOI: 10.3389/fnins.2020.00732] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 06/19/2020] [Indexed: 12/31/2022] Open
Abstract
The major aim of stroke therapies is to stimulate brain repair and to improve behavioral recuperation after cerebral ischemia. Despite remarkable advances in cell therapy for stroke, stem cell-based tissue replacement has not been achieved yet stimulating the search for alternative strategies for brain self-repair using the neurogenic zones of the brain, the dentate gyrus and the subventricular zone (SVZ). However, during aging, the potential of the hippocampus and the SVZ to generate new neuronal precursors, declines. We hypothesized that electrically stimulation of endogenous neurogenesis in aged rats could increase the odds of brain self-repair and improve behavioral recuperation after focal ischemia. Following stroke in aged animals, the rats were subjected to two sessions of electrical non-convulsive stimulation using ear-clip electrodes, at 7- and 24 days after MCAO. Animal were sacrificed after 48 days. We report that electrical stimulation (ES) stimulation of post-stroke aged rats led to an improved functional recovery of spatial long-term memory (T-maze) but not on the rotating pole or the inclined plane, both tests requiring complex sensorimotor skills. Surprisingly, ES had a detrimental effect on the asymmetric sensorimotor deficit. Histologically, there was a robust increase in the number of doublecortin-positive cells in the dentate gyrus and SVZ of the infarcted hemisphere and the presence of a considerable number of neurons expressing tubulin beta III in the infarcted area. Among the gene that were unique to ES, we noted increases in the expression of seizure related 6 homolog like which is one of the physiological substrate of the β-secretase BACE1 involved in the pathophysiology of the Alzheimer’s disease and Igfbp3 and BDNF receptor mRNAs which has been shown to have a neuroprotective effect after cerebral ischemia. However, ES was associated with a long-term down regulation of cortical gene expression after stroke in aged rats suggesting that gene expression in the peri-infarcted cortical area may not be related to electrical stimulation induced-neurogenesis in the subventricular zone and hippocampus.
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Affiliation(s)
- Adrian Tudor Balseanu
- Center of Clinical and Experimental Medicine, Department of Psychiatry, University of Medicine and Pharmacy of Craiova, Craiova, Romania
| | - Monica Grigore
- Center of Clinical and Experimental Medicine, Doctoral School, University of Medicine and Pharmacy of Craiova, Craiova, Romania
| | - Leonard-Radu Pinosanu
- Center of Clinical and Experimental Medicine, Doctoral School, University of Medicine and Pharmacy of Craiova, Craiova, Romania
| | - Mark Slevin
- Department of Life Sciences, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, United Kingdom
| | - Dirk M Hermann
- Department of Neurology the Chair of Vascular Neurology and Dementia, Essen University Hospital, Essen, Germany
| | - Daniela Glavan
- Center of Clinical and Experimental Medicine, Department of Psychiatry, University of Medicine and Pharmacy of Craiova, Craiova, Romania
| | - Aurel Popa-Wagner
- Center of Clinical and Experimental Medicine, Department of Psychiatry, University of Medicine and Pharmacy of Craiova, Craiova, Romania.,Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia
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8
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Abstract
DNA damage occurs on exposure to genotoxic agents and during physiological DNA transactions. DNA double-strand breaks (DSBs) are particularly dangerous lesions that activate DNA damage response (DDR) kinases, leading to initiation of a canonical DDR (cDDR). This response includes activation of cell cycle checkpoints and engagement of pathways that repair the DNA DSBs to maintain genomic integrity. In adaptive immune cells, programmed DNA DSBs are generated at precise genomic locations during the assembly and diversification of lymphocyte antigen receptor genes. In innate immune cells, the production of genotoxic agents, such as reactive nitrogen molecules, in response to pathogens can also cause genomic DNA DSBs. These DSBs in adaptive and innate immune cells activate the cDDR. However, recent studies have demonstrated that they also activate non-canonical DDRs (ncDDRs) that regulate cell type-specific processes that are important for innate and adaptive immune responses. Here, we review these ncDDRs and discuss how they integrate with other signals during immune system development and function.
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Affiliation(s)
- Jeffrey J Bednarski
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
| | - Barry P Sleckman
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA.
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9
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Bahjat M, Guikema JEJ. The Complex Interplay between DNA Injury and Repair in Enzymatically Induced Mutagenesis and DNA Damage in B Lymphocytes. Int J Mol Sci 2017; 18:ijms18091876. [PMID: 28867784 PMCID: PMC5618525 DOI: 10.3390/ijms18091876] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 08/24/2017] [Accepted: 08/29/2017] [Indexed: 11/25/2022] Open
Abstract
Lymphocytes are endowed with unique and specialized enzymatic mutagenic properties that allow them to diversify their antigen receptors, which are crucial sensors for pathogens and mediators of adaptive immunity. During lymphocyte development, the antigen receptors expressed by B and T lymphocytes are assembled in an antigen-independent fashion by ordered variable gene segment recombinations (V(D)J recombination), which is a highly ordered and regulated process that requires the recombination activating gene products 1 & 2 (RAG1, RAG2). Upon activation by antigen, B lymphocytes undergo additional diversifications of their immunoglobulin B-cell receptors. Enzymatically induced somatic hypermutation (SHM) and immunoglobulin class switch recombination (CSR) improves the affinity for antigen and shape the effector function of the humoral immune response, respectively. The activation-induced cytidine deaminase (AID) enzyme is crucial for both SHM and CSR. These processes have evolved to both utilize as well as evade different DNA repair and DNA damage response pathways. The delicate balance between enzymatic mutagenesis and DNA repair is crucial for effective immune responses and the maintenance of genomic integrity. Not surprisingly, disturbances in this balance are at the basis of lymphoid malignancies by provoking the formation of oncogenic mutations and chromosomal aberrations. In this review, we discuss recent mechanistic insight into the regulation of RAG1/2 and AID expression and activity in lymphocytes and the complex interplay between these mutagenic enzymes and DNA repair and DNA damage response pathways, focusing on the base excision repair and mismatch repair pathways. We discuss how disturbances of this interplay induce genomic instability and contribute to oncogenesis.
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Affiliation(s)
- Mahnoush Bahjat
- Department of Pathology, Academic Medical Center, University of Amsterdam; Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam 1105 AZ, The Netherlands.
| | - Jeroen E J Guikema
- Department of Pathology, Academic Medical Center, University of Amsterdam; Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam 1105 AZ, The Netherlands.
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10
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Arya R, Bassing CH. V(D)J Recombination Exploits DNA Damage Responses to Promote Immunity. Trends Genet 2017; 33:479-489. [PMID: 28532625 PMCID: PMC5499712 DOI: 10.1016/j.tig.2017.04.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 04/25/2017] [Accepted: 04/26/2017] [Indexed: 11/16/2022]
Abstract
It has been recognized for 40 years that the variable (diversity) joining [V(D)J] recombination-mediated assembly of diverse B and T lymphocyte antigen receptor (AgR) genes is not only essential for adaptive immunity, but also a risk for autoimmunity and lymphoid malignancies. Over the past few years, several studies have revealed that recombination-activating gene (RAG) endonuclease-induced DNA double-strand breaks (DSBs) transcend hazardous intermediates during antigen receptor gene assembly. RAG cleavage within the genomes of lymphocyte progenitors and immature lymphocytes regulates the expression of ubiquitous and lymphocyte-specific gene transcripts to control the differentiation and function of both adaptive and innate immune cell lineages. These unexpected discoveries raise important new questions that have broad implications for basic immunology research and the screening, diagnosis, and treatment of human immunological disease.
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Affiliation(s)
- Rahul Arya
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Craig H Bassing
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
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11
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GATA3 Abundance Is a Critical Determinant of T Cell Receptor β Allelic Exclusion. Mol Cell Biol 2017; 37:MCB.00052-17. [PMID: 28320875 DOI: 10.1128/mcb.00052-17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 03/14/2017] [Indexed: 12/30/2022] Open
Abstract
Allelic exclusion describes the essential immunological process by which feedback repression of sequential DNA rearrangements ensures that only one autosome expresses a functional T or B cell receptor. In wild-type mammals, approximately 60% of cells have recombined the DNA of one T cell receptor β (TCRβ) V-to-DJ-joined allele in a functional configuration, while the second allele has recombined only the DJ sequences; the other 40% of cells have recombined the V to the DJ segments on both alleles, with only one of the two alleles predicting a functional TCRβ protein. Here we report that the transgenic overexpression of GATA3 leads predominantly to biallelic TCRβ gene (Tcrb) recombination. We also found that wild-type immature thymocytes can be separated into distinct populations based on intracellular GATA3 expression and that GATA3LO cells had almost exclusively recombined only one Tcrb locus (that predicted a functional receptor sequence), while GATA3HI cells had uniformly recombined both Tcrb alleles (one predicting a functional and the other predicting a nonfunctional rearrangement). These data show that GATA3 abundance regulates the recombination propensity at the Tcrb locus and provide new mechanistic insight into the historic immunological conundrum for how Tcrb allelic exclusion is mediated.
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12
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Fisher MR, Rivera-Reyes A, Bloch NB, Schatz DG, Bassing CH. Immature Lymphocytes Inhibit Rag1 and Rag2 Transcription and V(D)J Recombination in Response to DNA Double-Strand Breaks. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2017; 198:2943-2956. [PMID: 28213501 PMCID: PMC5360515 DOI: 10.4049/jimmunol.1601639] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 01/16/2017] [Indexed: 12/26/2022]
Abstract
Mammalian cells have evolved a common DNA damage response (DDR) that sustains cellular function, maintains genomic integrity, and suppresses malignant transformation. In pre-B cells, DNA double-strand breaks (DSBs) induced at Igκ loci by the Rag1/Rag2 (RAG) endonuclease engage this DDR to modulate transcription of genes that regulate lymphocyte-specific processes. We previously reported that RAG DSBs induced at one Igκ allele signal through the ataxia telangiectasia mutated (ATM) kinase to feedback-inhibit RAG expression and RAG cleavage of the other Igκ allele. In this article, we show that DSBs induced by ionizing radiation, etoposide, or bleomycin suppress Rag1 and Rag2 mRNA levels in primary pre-B cells, pro-B cells, and pro-T cells, indicating that inhibition of Rag1 and Rag2 expression is a prevalent DSB response among immature lymphocytes. DSBs induced in pre-B cells signal rapid transcriptional repression of Rag1 and Rag2, causing downregulation of both Rag1 and Rag2 mRNA, but only Rag1 protein. This transcriptional inhibition requires the ATM kinase and the NF-κB essential modulator protein, implicating a role for ATM-mediated activation of canonical NF-κB transcription factors. Finally, we demonstrate that DSBs induced in pre-B cells by etoposide or bleomycin inhibit recombination of Igκ loci and a chromosomally integrated substrate. Our data indicate that immature lymphocytes exploit a common DDR signaling pathway to limit DSBs at multiple genomic locations within developmental stages wherein monoallelic Ag receptor locus recombination is enforced. We discuss the implications of our findings for mechanisms that orchestrate the differentiation of monospecific lymphocytes while suppressing oncogenic Ag receptor locus translocations.
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Affiliation(s)
- Megan R Fisher
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104
- Immunology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
- Department of Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
| | - Adrian Rivera-Reyes
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104
- Department of Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
- Cancer Biology Program of the Cell and Molecular Biology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104; and
| | - Noah B Bloch
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104
| | - David G Schatz
- Department of Immunobiology, Yale University School of Medicine, Howard Hughes Medical Institute, New Haven, CT 06520
| | - Craig H Bassing
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104;
- Immunology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
- Department of Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
- Cancer Biology Program of the Cell and Molecular Biology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104; and
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13
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DeMicco A, Reich T, Arya R, Rivera-Reyes A, Fisher MR, Bassing CH. Lymphocyte lineage-specific and developmental stage specific mechanisms suppress cyclin D3 expression in response to DNA double strand breaks. Cell Cycle 2016; 15:2882-2894. [PMID: 27327568 PMCID: PMC5105912 DOI: 10.1080/15384101.2016.1198861] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 06/01/2016] [Accepted: 06/02/2016] [Indexed: 12/16/2022] Open
Abstract
Mammalian cells are thought to protect themselves and their host organisms from DNA double strand breaks (DSBs) through universal mechanisms that restrain cellular proliferation until DNA is repaired. The Cyclin D3 protein drives G1-to-S cell cycle progression and is required for proliferation of immature T and B cells and of mature B cells during a T cell-dependent immune response. We demonstrate that mouse thymocytes and pre-B cells, but not mature B cells, repress Cyclin D3 protein levels in response to DSBs. This response requires the ATM protein kinase that is activated by DSBs. Cyclin D3 protein loss in thymocytes coincides with decreased association of Cyclin D3 mRNA with the HuR RNA binding protein that ATM regulates. HuR inactivation reduces basal Cyclin D3 protein levels without affecting Cyclin D3 mRNA levels, indicating that thymocytes repress Cyclin D3 expression via ATM-dependent inhibition of Cyclin D3 mRNA translation. In contrast, ATM-dependent transcriptional repression of the Cyclin D3 gene represses Cyclin D3 protein levels in pre-B cells. Retrovirus-driven Cyclin D3 expression is resistant to transcriptional repression by DSBs; this prevents pre-B cells from suppressing Cyclin D3 protein levels and from inhibiting DNA synthesis to the normal extent following DSBs. Our data indicate that immature B and T cells use lymphocyte lineage- and developmental stage-specific mechanisms to inhibit Cyclin D3 protein levels and thereby help prevent cellular proliferation in response to DSBs. We discuss the relevance of these cellular context-dependent DSB response mechanisms in restraining proliferation, maintaining genomic integrity, and suppressing malignant transformation of lymphocytes.
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Affiliation(s)
- Amy DeMicco
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Tyler Reich
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Rahul Arya
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Adrian Rivera-Reyes
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Megan R. Fisher
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Immunology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Craig H. Bassing
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
- Immunology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
- Department of Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
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14
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Vogel KU, Bell LS, Galloway A, Ahlfors H, Turner M. The RNA-Binding Proteins Zfp36l1 and Zfp36l2 Enforce the Thymic β-Selection Checkpoint by Limiting DNA Damage Response Signaling and Cell Cycle Progression. THE JOURNAL OF IMMUNOLOGY 2016; 197:2673-2685. [PMID: 27566829 DOI: 10.4049/jimmunol.1600854] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 07/26/2016] [Indexed: 11/19/2022]
Abstract
The RNA-binding proteins Zfp36l1 and Zfp36l2 act redundantly to enforce the β-selection checkpoint during thymopoiesis, yet their molecular targets remain largely unknown. In this study, we identify these targets on a genome-wide scale in primary mouse thymocytes and show that Zfp36l1/l2 regulate DNA damage response and cell cycle transcripts to ensure proper β-selection. Double-negative 3 thymocytes lacking Zfp36l1/l2 share a gene expression profile with postselected double-negative 3b cells despite the absence of intracellular TCRβ and reduced IL-7 signaling. Our findings show that in addition to controlling the timing of proliferation at β-selection, posttranscriptional control by Zfp36l1/l2 limits DNA damage responses, which are known to promote thymocyte differentiation. Zfp36l1/l2 therefore act as posttranscriptional safeguards against chromosomal instability and replication stress by integrating pre-TCR and IL-7 signaling with DNA damage and cell cycle control.
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Affiliation(s)
| | - Lewis S Bell
- Dept. of Medicine, University of Cambridge, MRC-Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Alison Galloway
- Centre for Gene Regulation and Expression, School of Life Science, University of Dundee, Dundee DD1 5EH, UK
| | - Helena Ahlfors
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - Martin Turner
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK
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15
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Ochodnicka-Mackovicova K, Bahjat M, Maas C, van der Veen A, Bloedjes TA, de Bruin AM, van Andel H, Schrader CE, Hendriks RW, Verhoeyen E, Bende RJ, van Noesel CJM, Guikema JEJ. The DNA Damage Response Regulates RAG1/2 Expression in Pre-B Cells through ATM-FOXO1 Signaling. THE JOURNAL OF IMMUNOLOGY 2016; 197:2918-29. [PMID: 27559048 DOI: 10.4049/jimmunol.1501989] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 07/20/2016] [Indexed: 01/01/2023]
Abstract
The recombination activating gene (RAG) 1 and RAG2 protein complex introduces DNA breaks at Tcr and Ig gene segments that are required for V(D)J recombination in developing lymphocytes. Proper regulation of RAG1/2 expression safeguards the ordered assembly of Ag receptors and the development of lymphocytes, while minimizing the risk for collateral damage. The ataxia telangiectasia mutated (ATM) kinase is involved in the repair of RAG1/2-mediated DNA breaks and prevents their propagation. The simultaneous occurrence of RAG1/2-dependent and -independent DNA breaks in developing lymphocytes exposed to genotoxic stress increases the risk for aberrant recombinations. In this study, we assessed the effect of genotoxic stress on RAG1/2 expression in pre-B cells and show that activation of the DNA damage response resulted in the rapid ATM-dependent downregulation of RAG1/2 mRNA and protein expression. We show that DNA damage led to the loss of FOXO1 binding to the enhancer region of the RAG1/2 locus (Erag) and provoked FOXO1 cleavage. We also show that DNA damage caused by RAG1/2 activity in pre-B cells was able to downmodulate RAG1/2 expression and activity, confirming the existence of a negative feedback regulatory mechanism. Our data suggest that pre-B cells are endowed with a protective mechanism that reduces the risk for aberrant recombinations and chromosomal translocations when exposed to DNA damage, involving the ATM-dependent regulation of FOXO1 binding to the Erag enhancer region.
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Affiliation(s)
- Katarina Ochodnicka-Mackovicova
- Department of Pathology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; Lymphoma and Myeloma Center Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Mahnoush Bahjat
- Department of Pathology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; Lymphoma and Myeloma Center Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Chiel Maas
- Department of Pathology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; Lymphoma and Myeloma Center Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Amélie van der Veen
- Department of Pathology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; Lymphoma and Myeloma Center Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Timon A Bloedjes
- Department of Pathology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; Lymphoma and Myeloma Center Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Alexander M de Bruin
- Department of Pathology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; Lymphoma and Myeloma Center Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Harmen van Andel
- Department of Pathology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; Lymphoma and Myeloma Center Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Carol E Schrader
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01655
| | - Rudi W Hendriks
- Department of Pulmonary Medicine, Erasmus MC, 3000 CA Rotterdam, the Netherlands
| | - Els Verhoeyen
- Centre International de Recherche en Infectiologie, Virus Enveloppés, Vecteurs et Réponses Innées Équipe, INSERM U1111, CNRS, UMR5308, Université de Lyon-1, École Normale Supérieure de Lyon, 69007 Lyon, France; and INSERM, U1065, Centre de Médecine Moléculaire, Équipe 3, 06204 Nice, France
| | - Richard J Bende
- Department of Pathology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; Lymphoma and Myeloma Center Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Carel J M van Noesel
- Department of Pathology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; Lymphoma and Myeloma Center Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Jeroen E J Guikema
- Department of Pathology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; Lymphoma and Myeloma Center Amsterdam, 1105 AZ Amsterdam, the Netherlands;
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16
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Neal JA, Xu Y, Abe M, Hendrickson E, Meek K. Restoration of ATM Expression in DNA-PKcs-Deficient Cells Inhibits Signal End Joining. THE JOURNAL OF IMMUNOLOGY 2016; 196:3032-42. [PMID: 26921311 DOI: 10.4049/jimmunol.1501654] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 01/26/2016] [Indexed: 11/19/2022]
Abstract
Unlike most DNA-dependent protein kinase, catalytic subunit (DNA-PKcs)-deficient mouse cell strains, we show in the present study that targeted deletion of DNA-PKcs in two different human cell lines abrogates VDJ signal end joining in episomal assays. Although the mechanism is not well defined, DNA-PKcs deficiency results in spontaneous reduction of ATM expression in many cultured cell lines (including those examined in this study) and in DNA-PKcs-deficient mice. We considered that varying loss of ATM expression might explain differences in signal end joining in different cell strains and animal models, and we investigated the impact of ATM and/or DNA-PKcs loss on VDJ recombination in cultured human and rodent cell strains. To our surprise, in DNA-PKcs-deficient mouse cell strains that are proficient in signal end joining, restoration of ATM expression markedly inhibits signal end joining. In contrast, in DNA-PKcs-deficient cells that are deficient in signal end joining, complete loss of ATM enhances signal (but not coding) joint formation. We propose that ATM facilitates restriction of signal ends to the classical nonhomologous end-joining pathway.
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Affiliation(s)
- Jessica A Neal
- Department of Microbiology and Molecular Genetics, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824; Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824
| | - Yao Xu
- Department of Microbiology and Molecular Genetics, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824; Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824
| | - Masumi Abe
- National Institute of Radiological Sciences, Chiba 263-8555, Japan; and
| | - Eric Hendrickson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455
| | - Katheryn Meek
- Department of Microbiology and Molecular Genetics, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824; Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824;
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17
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How cancer cells hijack DNA double-strand break repair pathways to gain genomic instability. Biochem J 2015; 471:1-11. [PMID: 26392571 DOI: 10.1042/bj20150582] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
DNA DSBs (double-strand breaks) are a significant threat to the viability of a normal cell, since they can result in loss of genetic material if mitosis or replication is attempted in their presence. Consequently, evolutionary pressure has resulted in multiple pathways and responses to enable DSBs to be repaired efficiently and faithfully. Cancer cells, which are under pressure to gain genomic instability, have a striking ability to avoid the elegant mechanisms by which normal cells maintain genomic stability. Current models suggest that, in normal cells, DSB repair occurs in a hierarchical manner that promotes rapid and efficient rejoining first, with the utilization of additional steps or pathways of diminished accuracy if rejoining is unsuccessful or delayed. In the present review, we evaluate the fidelity of DSB repair pathways and discuss how cancer cells promote the utilization of less accurate processes. Homologous recombination serves to promote accuracy and stability during replication, providing a battlefield for cancer to gain instability. Non-homologous end-joining, a major DSB repair pathway in mammalian cells, usually operates with high fidelity and only switches to less faithful modes if timely repair fails. The transition step is finely tuned and provides another point of attack during tumour progression. In addition to DSB repair, a DSB signalling response activates processes such as cell cycle checkpoint arrest, which enhance the possibility of accurate DSB repair. We consider the ways by which cancers modify and hijack these processes to gain genomic instability.
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18
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Outters P, Jaeger S, Zaarour N, Ferrier P. Long-Range Control of V(D)J Recombination & Allelic Exclusion: Modeling Views. Adv Immunol 2015; 128:363-413. [PMID: 26477371 DOI: 10.1016/bs.ai.2015.08.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Allelic exclusion of immunoglobulin (Ig) and T-cell receptor (TCR) genes ensures the development of B and T lymphocytes operating under the mode of clonal selection. This phenomenon associates asynchronous V(D)J recombination events at Ig or TCR alleles and inhibitory feedback control. Despite years of intense research, however, the mechanisms that sustain asymmetric choice in random Ig/TCR dual allele usage and the production of Ig/TCR monoallelic expressing B and T lymphocytes remain unclear and open for debate. In this chapter, we first recapitulate the biological evidence that almost from the start appeared to link V(D)J recombination and allelic exclusion. We review the theoretical models previously proposed to explain this connection. Finally, we introduce our own mathematical modeling views based on how the developmental dynamics of individual lymphoid cells combine to sustain allelic exclusion.
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Affiliation(s)
- Pernelle Outters
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288 Marseille, France
| | - Sébastien Jaeger
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288 Marseille, France
| | - Nancy Zaarour
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288 Marseille, France
| | - Pierre Ferrier
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288 Marseille, France.
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19
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Proudhon C, Hao B, Raviram R, Chaumeil J, Skok JA. Long-Range Regulation of V(D)J Recombination. Adv Immunol 2015; 128:123-82. [PMID: 26477367 DOI: 10.1016/bs.ai.2015.07.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Given their essential role in adaptive immunity, antigen receptor loci have been the focus of analysis for many years and are among a handful of the most well-studied genes in the genome. Their investigation led initially to a detailed knowledge of linear structure and characterization of regulatory elements that confer control of their rearrangement and expression. However, advances in DNA FISH and imaging combined with new molecular approaches that interrogate chromosome conformation have led to a growing appreciation that linear structure is only one aspect of gene regulation and in more recent years, the focus has switched to analyzing the impact of locus conformation and nuclear organization on control of recombination. Despite decades of work and intense effort from numerous labs, we are still left with an incomplete picture of how the assembly of antigen receptor loci is regulated. This chapter summarizes our advances to date and points to areas that need further investigation.
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Affiliation(s)
- Charlotte Proudhon
- Department of Pathology, New York University School of Medicine, New York, USA
| | - Bingtao Hao
- Department of Pathology, New York University School of Medicine, New York, USA
| | - Ramya Raviram
- Department of Pathology, New York University School of Medicine, New York, USA
| | - Julie Chaumeil
- Institut Curie, CNRS UMR3215, INSERM U934, Paris, France
| | - Jane A Skok
- Department of Pathology, New York University School of Medicine, New York, USA.
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20
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Majumder K, Bassing CH, Oltz EM. Regulation of Tcrb Gene Assembly by Genetic, Epigenetic, and Topological Mechanisms. Adv Immunol 2015; 128:273-306. [PMID: 26477369 DOI: 10.1016/bs.ai.2015.07.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The adaptive immune system endows mammals with an ability to recognize nearly any foreign invader through antigen receptors that are expressed on the surface of all lymphocytes. This defense network is generated by V(D)J recombination, a set of sequentially controlled DNA cleavage and repair events that assemble antigen receptor genes from physically separated variable (V), joining (J), and sometimes diversity (D) gene segments. The recombination process itself must be stringently regulated to minimize oncogenic translocations involving chromosomes that harbor immunoglobulin and T cell receptor loci. Indeed, V(D)J recombination is controlled at several levels, including tissue-, developmental stage-, allele-, and gene segment-specificity. These levels of control are imposed by a collection of architectural and regulatory elements that are distributed throughout each antigen receptor locus. Together, the genetic elements regulate developmental changes in chromatin, transcription, and locus topology that promote or disfavor long-range recombination. This chapter focuses on the cross talk between these mechanisms at the T cell receptor beta (Tcrb) locus, and how they sculpt a diverse TCRβ repertoire while maintaining monospecificity of this antigen receptor on each mature T lymphocyte. We also discuss how insights obtained from studies of Tcrb are more generally relevant to our understanding of gene regulation strategies employed by mammals.
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Affiliation(s)
- Kinjal Majumder
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, Missouri, USA
| | - Craig H Bassing
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; Abramson Family Cancer Research Institute, Cell and Molecular Biology Graduate Program, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Eugene M Oltz
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, Missouri, USA.
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