1
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Polmear J, Hailes L, Olshansky M, Rischmueller M, L'Estrange‐Stranieri E, Fletcher AL, Hibbs ML, Bryant VL, Good‐Jacobson KL. Targeting BMI-1 to deplete antibody-secreting cells in autoimmunity. Clin Transl Immunology 2023; 12:e1470. [PMID: 37799772 PMCID: PMC10550498 DOI: 10.1002/cti2.1470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/13/2023] [Accepted: 09/22/2023] [Indexed: 10/07/2023] Open
Abstract
Objectives B cells drive the production of autoreactive antibody-secreting cells (ASCs) in autoimmune diseases such as Systemic Lupus Erythematosus (SLE) and Sjögren's syndrome, causing long-term organ damage. Current treatments for antibody-mediated autoimmune diseases target B cells or broadly suppress the immune system. However, pre-existing long-lived ASCs are often refractory to treatment, leaving a reservoir of autoreactive cells that continue to produce antibodies. Therefore, the development of novel treatment methods targeting ASCs is vital to improve patient outcomes. Our objective was to test whether targeting the epigenetic regulator BMI-1 could deplete ASCs in autoimmune conditions in vivo and in vitro. Methods Use of a BMI-1 inhibitor in both mouse and human autoimmune settings was investigated. Lyn -/- mice, a model of SLE, were treated with the BMI-1 small molecule inhibitor PTC-028, before assessment of ASCs, serum antibody and immune complexes. To examine human ASC survival, a novel human fibroblast-based assay was established, and the impact of PTC-028 on ASCs derived from Sjögren's syndrome patients was evaluated. Results BMI-1 inhibition significantly decreased splenic and bone marrow ASCs in Lyn -/- mice. The decline in ASCs was linked to aberrant cell cycle gene expression and led to a significant decrease in serum IgG3, immune complexes and anti-DNA IgG. PTC-028 was also efficacious in reducing ex vivo plasma cell survival from both Sjögren's syndrome patients and age-matched healthy donors. Conclusion These data provide evidence that inhibiting BMI-1 can deplete ASC in a variety of contexts and thus BMI-1 is a viable therapeutic target for antibody-mediated autoimmune diseases.
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Affiliation(s)
- Jack Polmear
- Department of Biochemistry and Molecular BiologyMonash UniversityClaytonVICAustralia
- Immunity Program, Biomedicine Discovery InstituteMonash UniversityClaytonVICAustralia
| | - Lauren Hailes
- Department of Biochemistry and Molecular BiologyMonash UniversityClaytonVICAustralia
- Immunity Program, Biomedicine Discovery InstituteMonash UniversityClaytonVICAustralia
| | - Moshe Olshansky
- Department of Biochemistry and Molecular BiologyMonash UniversityClaytonVICAustralia
- Immunity Program, Biomedicine Discovery InstituteMonash UniversityClaytonVICAustralia
| | - Maureen Rischmueller
- The Queen Elizabeth Hospital and Basil Hetzel InstituteWoodville SouthSAAustralia
- Adelaide Medical SchoolUniversity of AdelaideAdelaideSAAustralia
| | | | - Anne L Fletcher
- Department of Biochemistry and Molecular BiologyMonash UniversityClaytonVICAustralia
- Immunity Program, Biomedicine Discovery InstituteMonash UniversityClaytonVICAustralia
| | - Margaret L Hibbs
- Department of Immunology, Alfred Research AllianceMonash UniversityMelbourneVICAustralia
| | - Vanessa L Bryant
- Immunology DivisionWalter & Eliza Hall InstituteParkvilleVICAustralia
- Department of Medical BiologyUniversity of MelbourneParkvilleVICAustralia
- Department of Clinical Immunology & AllergyThe Royal Melbourne HospitalParkvilleVICAustralia
| | - Kim L Good‐Jacobson
- Department of Biochemistry and Molecular BiologyMonash UniversityClaytonVICAustralia
- Immunity Program, Biomedicine Discovery InstituteMonash UniversityClaytonVICAustralia
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2
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Mielczarek O, Rogers CH, Zhan Y, Matheson LS, Stubbington MJT, Schoenfelder S, Bolland DJ, Javierre BM, Wingett SW, Várnai C, Segonds-Pichon A, Conn SJ, Krueger F, Andrews S, Fraser P, Giorgetti L, Corcoran AE. Intra- and interchromosomal contact mapping reveals the Igh locus has extensive conformational heterogeneity and interacts with B-lineage genes. Cell Rep 2023; 42:113074. [PMID: 37676766 PMCID: PMC10548092 DOI: 10.1016/j.celrep.2023.113074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 06/28/2023] [Accepted: 08/18/2023] [Indexed: 09/09/2023] Open
Abstract
To produce a diverse antibody repertoire, immunoglobulin heavy-chain (Igh) loci undergo large-scale alterations in structure to facilitate juxtaposition and recombination of spatially separated variable (VH), diversity (DH), and joining (JH) genes. These chromosomal alterations are poorly understood. Uncovering their patterns shows how chromosome dynamics underpins antibody diversity. Using tiled Capture Hi-C, we produce a comprehensive map of chromatin interactions throughout the 2.8-Mb Igh locus in progenitor B cells. We find that the Igh locus folds into semi-rigid subdomains and undergoes flexible looping of the VH genes to its 3' end, reconciling two views of locus organization. Deconvolution of single Igh locus conformations using polymer simulations identifies thousands of different structures. This heterogeneity may underpin the diversity of V(D)J recombination events. All three immunoglobulin loci also participate in a highly specific, developmentally regulated network of interchromosomal interactions with genes encoding B cell-lineage factors. This suggests a model of interchromosomal coordination of B cell development.
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Affiliation(s)
- Olga Mielczarek
- Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Carolyn H Rogers
- Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK; Immunology Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Yinxiu Zhan
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Louise S Matheson
- Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK; Immunology Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Michael J T Stubbington
- Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Stefan Schoenfelder
- Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Daniel J Bolland
- Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK; Immunology Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Biola M Javierre
- Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Steven W Wingett
- Bioinformatics Group, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Csilla Várnai
- Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Anne Segonds-Pichon
- Bioinformatics Group, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Simon J Conn
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, SA 5042, Australia
| | - Felix Krueger
- Bioinformatics Group, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Simon Andrews
- Bioinformatics Group, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Peter Fraser
- Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Luca Giorgetti
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Anne E Corcoran
- Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK; Immunology Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK.
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3
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Bruzeau C, Cook-Moreau J, Pinaud E, Le Noir S. Contribution of Immunoglobulin Enhancers to B Cell Nuclear Organization. Front Immunol 2022; 13:877930. [PMID: 35812441 PMCID: PMC9263370 DOI: 10.3389/fimmu.2022.877930] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 05/26/2022] [Indexed: 11/19/2022] Open
Abstract
B cells undergo genetic rearrangements at immunoglobulin gene (Ig) loci during B cell maturation. First V(D)J recombination occurs during early B cell stages followed by class switch recombination (CSR) and somatic hypermutation (SHM) which occur during mature B cell stages. Given that RAG1/2 induces DNA double strand breaks (DSBs) during V(D)J recombination and AID (Activation-Induced Deaminase) leads to DNA modifications (mutations during SHM or DNA DSBs during CSR), it is mandatory that IgH rearrangements be tightly regulated to avoid any mutations or translocations within oncogenes. Ig loci contain various cis-regulatory elements that are involved in germline transcription, chromatin modifications or RAG/AID recruitment. Ig cis-regulatory elements are increasingly recognized as being involved in nuclear positioning, heterochromatin addressing and chromosome loop regulation. In this review, we examined multiple data showing the critical interest of studying Ig gene regulation at the whole nucleus scale. In this context, we highlighted the essential function of Ig gene regulatory elements that now have to be considered as nuclear organizers in B lymphocytes.
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4
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Qiu X, Ma F, Zhao M, Cao Y, Shipp L, Liu A, Dutta A, Singh A, Braikia FZ, De S, Wood WH, Becker KG, Zhou W, Ji H, Zhao K, Atchison ML, Sen R. Altered 3D chromatin structure permits inversional recombination at the IgH locus. SCIENCE ADVANCES 2020; 6:eaaz8850. [PMID: 32851160 PMCID: PMC7428332 DOI: 10.1126/sciadv.aaz8850] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 07/01/2020] [Indexed: 05/05/2023]
Abstract
Immunoglobulin heavy chain (IgH) genes are assembled by two sequential DNA rearrangement events that are initiated by recombination activating gene products (RAG) 1 and 2. Diversity (DH) gene segments rearrange first, followed by variable (VH) gene rearrangements. Here, we provide evidence that each rearrangement step is guided by different rules of engagement between rearranging gene segments. DH gene segments, which recombine by deletion of intervening DNA, must be located within a RAG1/2 scanning domain for efficient recombination. In the absence of intergenic control region 1, a regulatory sequence that delineates the RAG scanning domain on wild-type IgH alleles, VH and DH gene segments can recombine with each other by both deletion and inversion of intervening DNA. We propose that VH gene segments find their targets by distinct mechanisms from those that apply to DH gene segments. These distinctions may underlie differential allelic choice associated with each step of IgH gene assembly.
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Affiliation(s)
- Xiang Qiu
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD 21224, USA
| | - Fei Ma
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD 21224, USA
| | - Mingming Zhao
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD 21224, USA
| | - Yaqiang Cao
- Laboratory of Epigenome Biology, Systems Biology Center, National Heart Lung and Blood Institute, Bethesda, MD 20892, USA
| | - Lillian Shipp
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD 21224, USA
| | - Angela Liu
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD 21224, USA
| | - Arun Dutta
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD 21224, USA
| | - Amit Singh
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD 21224, USA
| | - Fatima Zohra Braikia
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD 21224, USA
| | - Supriyo De
- Laboratory of Genetics and Genomics, National Institute on Aging, Baltimore, MD 21224, USA
| | - William H. Wood
- Laboratory of Genetics and Genomics, National Institute on Aging, Baltimore, MD 21224, USA
| | - Kevin G. Becker
- Laboratory of Genetics and Genomics, National Institute on Aging, Baltimore, MD 21224, USA
| | - Weiqiang Zhou
- Department of Biostatistics, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Hongkai Ji
- Department of Biostatistics, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Keji Zhao
- Laboratory of Epigenome Biology, Systems Biology Center, National Heart Lung and Blood Institute, Bethesda, MD 20892, USA
| | - Michael L. Atchison
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Ranjan Sen
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD 21224, USA
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5
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Oudinet C, Braikia FZ, Dauba A, Khamlichi AA. Mechanism and regulation of class switch recombination by IgH transcriptional control elements. Adv Immunol 2020; 147:89-137. [PMID: 32981636 DOI: 10.1016/bs.ai.2020.06.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Class switch recombination (CSR) plays an important role in humoral immunity by generating antibodies with different effector functions. CSR to a particular antibody isotype is induced by external stimuli, and occurs between highly repetitive switch (S) sequences. CSR requires transcription across S regions, which generates long non-coding RNAs and secondary structures that promote accessibility of S sequences to activation-induced cytidine deaminase (AID). AID initiates DNA double-strand breaks (DSBs) intermediates that are repaired by general DNA repair pathways. Switch transcription is controlled by various regulatory elements, including enhancers and insulators. The current paradigm posits that transcriptional control of CSR involves long-range chromatin interactions between regulatory elements and chromatin loops-stabilizing factors, which promote alignment of partner S regions in a CSR centre (CSRC) and initiation of CSR. In this review, we focus on the role of IgH transcriptional control elements in CSR and the chromatin-based mechanisms underlying this control.
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Affiliation(s)
- Chloé Oudinet
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, Toulouse, France; Institut de Pharmacologie et de Biologie Structurale, CNRS, Université Paul Sabatier, Toulouse, France
| | - Fatima-Zohra Braikia
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, Toulouse, France; Institut de Pharmacologie et de Biologie Structurale, CNRS, Université Paul Sabatier, Toulouse, France
| | - Audrey Dauba
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, Toulouse, France; Institut de Pharmacologie et de Biologie Structurale, CNRS, Université Paul Sabatier, Toulouse, France
| | - Ahmed Amine Khamlichi
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, Toulouse, France; Institut de Pharmacologie et de Biologie Structurale, CNRS, Université Paul Sabatier, Toulouse, France.
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6
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Honjo K, Won WJ, King RG, Ianov L, Crossman DK, Easlick JL, Shakhmatov MA, Khass M, Vale AM, Stephan RP, Li R, Davis RS. Fc Receptor-Like 6 (FCRL6) Discloses Progenitor B Cell Heterogeneity That Correlates With Pre-BCR Dependent and Independent Pathways of Natural Antibody Selection. Front Immunol 2020; 11:82. [PMID: 32117244 PMCID: PMC7033751 DOI: 10.3389/fimmu.2020.00082] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 01/13/2020] [Indexed: 11/24/2022] Open
Abstract
B-1a cells produce "natural" antibodies (Abs) to neutralize pathogens and clear neo self-antigens, but the fundamental selection mechanisms that shape their polyreactive repertoires are poorly understood. Here, we identified a B cell progenitor subset defined by Fc receptor-like 6 (FCRL6) expression, harboring innate-like defense, migration, and differentiation properties conducive for natural Ab generation. Compared to FCRL6- pro B cells, the repressed mitotic, DNA damage repair, and signaling activity of FCRL6+ progenitors, yielded VH repertoires with biased distal Ighv segment accessibility, constrained diversity, and hydrophobic and charged CDR-H3 sequences. Beyond nascent autoreactivity, VH11 productivity, which predominates phosphatidylcholine-specific B-1a B cell receptors (BCRs), was higher for FCRL6+ cells as was pre-BCR formation, which was required for Myc induction and VH11, but not VH12, B-1a development. Thus, FCRL6 revealed unexpected heterogeneity in the developmental origins, regulation, and selection of natural Abs at the pre-BCR checkpoint with implications for autoimmunity and lymphoproliferative disorders.
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MESH Headings
- Animals
- Antibodies/immunology
- Antibodies/metabolism
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Female
- Humans
- Immunoglobulin Heavy Chains/genetics
- Immunoglobulin Heavy Chains/immunology
- Immunoglobulin Variable Region/genetics
- Immunoglobulin Variable Region/immunology
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- Phosphatidylcholines/immunology
- Phosphatidylcholines/metabolism
- Precursor Cells, B-Lymphoid/immunology
- Precursor Cells, B-Lymphoid/metabolism
- Receptors, Antigen, B-Cell/genetics
- Receptors, Antigen, B-Cell/immunology
- Receptors, Antigen, B-Cell/metabolism
- Receptors, Fc/genetics
- Receptors, Fc/immunology
- Receptors, Fc/metabolism
- Signal Transduction/genetics
- Signal Transduction/immunology
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Affiliation(s)
- Kazuhito Honjo
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Woong-Jai Won
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Rodney G. King
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Lara Ianov
- Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - David K. Crossman
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Juliet L. Easlick
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Mikhail A. Shakhmatov
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Mohamed Khass
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Genetic Engineering and Biotechnology Division, National Research Center, Cairo, Egypt
| | - Andre M. Vale
- Program in Immunobiology, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Robert P. Stephan
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ran Li
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Randall S. Davis
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, United States
- Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, United States
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7
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Ciccone DN, Namiki Y, Chen C, Morshead KB, Wood AL, Johnston CM, Morris JW, Wang Y, Sadreyev R, Corcoran AE, Matthews AGW, Oettinger MA. The murine IgH locus contains a distinct DNA sequence motif for the chromatin regulatory factor CTCF. J Biol Chem 2019; 294:13580-13592. [PMID: 31285261 PMCID: PMC6746451 DOI: 10.1074/jbc.ra118.007348] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 06/13/2019] [Indexed: 01/03/2023] Open
Abstract
Antigen receptor assembly in lymphocytes involves stringently-regulated coordination of specific DNA rearrangement events across several large chromosomal domains. Previous studies indicate that transcription factors such as paired box 5 (PAX5), Yin Yang 1 (YY1), and CCCTC-binding factor (CTCF) play a role in regulating the accessibility of the antigen receptor loci to the V(D)J recombinase, which is required for these rearrangements. To gain clues about the role of CTCF binding at the murine immunoglobulin heavy chain (IgH) locus, we utilized a computational approach that identified 144 putative CTCF-binding sites within this locus. We found that these CTCF sites share a consensus motif distinct from other CTCF sites in the mouse genome. Additionally, we could divide these CTCF sites into three categories: intergenic sites remote from any coding element, upstream sites present within 8 kb of the VH-leader exon, and recombination signal sequence (RSS)-associated sites characteristically located at a fixed distance (∼18 bp) downstream of the RSS. We noted that the intergenic and upstream sites are located in the distal portion of the VH locus, whereas the RSS-associated sites are located in the DH-proximal region. Computational analysis indicated that the prevalence of CTCF-binding sites at the IgH locus is evolutionarily conserved. In all species analyzed, these sites exhibit a striking strand-orientation bias, with >98% of the murine sites being present in one orientation with respect to VH gene transcription. Electrophoretic mobility shift and enhancer-blocking assays and ChIP–chip analysis confirmed CTCF binding to these sites both in vitro and in vivo.
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Affiliation(s)
- David N Ciccone
- Department of Molecular Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114
| | - Yuka Namiki
- Department of Molecular Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114
| | - Changfeng Chen
- Department of Molecular Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114
| | - Katrina B Morshead
- Department of Molecular Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114
| | - Andrew L Wood
- Lymphocyte Signalling and Development, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom
| | - Colette M Johnston
- Lymphocyte Signalling and Development, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom
| | - John W Morris
- Department of Molecular Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114
| | - Yanqun Wang
- Department of Molecular Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114
| | - Ruslan Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114
| | - Anne E Corcoran
- Lymphocyte Signalling and Development, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom
| | - Adam G W Matthews
- Department of Molecular Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114.,Department of Biological Sciences and Program in Biochemistry, Wellesley College, Wellesley, Massachusetts 02481
| | - Marjorie A Oettinger
- Department of Molecular Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114
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8
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9
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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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10
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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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11
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Inducible CTCF insulator delays the IgH 3' regulatory region-mediated activation of germline promoters and alters class switching. Proc Natl Acad Sci U S A 2017; 114:6092-6097. [PMID: 28533409 DOI: 10.1073/pnas.1701631114] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Class switch recombination (CSR) plays an important role in adaptive immune response by enabling mature B cells to switch from IgM expression to the expression of downstream isotypes. CSR is preceded by inducible germline (GL) transcription of the constant genes and is controlled by the 3' regulatory region (3'RR) in a stimulus-dependent manner. Why the 3'RR-mediated up-regulation of GL transcription is delayed to the mature B-cell stage is presently unknown. Here we show that mice devoid of an inducible CTCF binding element, located in the α constant gene, display a marked isotype-specific increase of GL transcription in developing and resting splenic B cells and altered CSR in activated B cells. Moreover, insertion of a GL promoter downstream of the CTCF insulator led to premature activation of the ectopic promoter. This study provides functional evidence that the 3'RR has a developmentally controlled potential to constitutively activate GL promoters but that this activity is delayed, at least in part, by the CTCF insulator, which borders a transcriptionally active domain established by the 3'RR in developing B cells.
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12
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Regulated large-scale nucleosome density patterns and precise nucleosome positioning correlate with V(D)J recombination. Proc Natl Acad Sci U S A 2016; 113:E6427-E6436. [PMID: 27698124 DOI: 10.1073/pnas.1605543113] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
We show that the physical distribution of nucleosomes at antigen receptor loci is subject to regulated cell type-specific and lineage-specific positioning and correlates with the accessibility of these gene segments to recombination. At the Ig heavy chain locus (IgH), a nucleosome in pro-B cells is generally positioned over each IgH variable (VH) coding segment, directly adjacent to the recombination signal sequence (RSS), placing the RSS in a position accessible to the recombination activating gene (RAG) recombinase. These changes result in establishment of a specific chromatin organization at the RSS that facilitates accessibility of the genomic DNA for the RAG recombinase. In contrast, in mouse embryonic fibroblasts the coding segment is depleted of nucleosomes, which instead cover the RSS, thereby rendering it inaccessible. Pro-T cells exhibit a pattern intermediate between pro-B cells and mouse embryonic fibroblasts. We also find large-scale variations of nucleosome density over hundreds of kilobases, delineating chromosomal domains within IgH, in a cell type-dependent manner. These findings suggest that developmentally regulated changes in nucleosome location and occupancy, in addition to the known chromatin modifications, play a fundamental role in regulating V(D)J recombination. Nucleosome positioning-which has previously been observed to vary locally at individual enhancers and promoters-may be a more general mechanism by which cells can regulate the accessibility of the genome during development, at scales ranging from several hundred base pairs to many kilobases.
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13
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Sequential activation and distinct functions for distal and proximal modules within the IgH 3' regulatory region. Proc Natl Acad Sci U S A 2016; 113:1618-23. [PMID: 26831080 DOI: 10.1073/pnas.1514090113] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
As a master regulator of functional Ig heavy chain (IgH) expression, the IgH 3' regulatory region (3'RR) controls multiple transcription events at various stages of B-cell ontogeny, from newly formed B cells until the ultimate plasma cell stage. The IgH 3'RR plays a pivotal role in early B-cell receptor expression, germ-line transcription preceding class switch recombination, interactions between targeted switch (S) regions, variable region transcription before somatic hypermutation, and antibody heavy chain production, but the functional ranking of its different elements is still inaccurate, especially that of its evolutionarily conserved quasi-palindromic structure. By comparing relevant previous knockout (KO) mouse models (3'RR KO and hs3b-4 KO) to a novel mutant devoid of the 3'RR quasi-palindromic region (3'PAL KO), we pinpointed common features and differences that specify two distinct regulatory entities acting sequentially during B-cell ontogeny. Independently of exogenous antigens, the 3'RR distal part, including hs4, fine-tuned B-cell receptor expression in newly formed and naïve B-cell subsets. At mature stages, the 3'RR portion including the quasi-palindrome dictated antigen-dependent locus remodeling (global somatic hypermutation and class switch recombination to major isotypes) in activated B cells and antibody production in plasma cells.
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Petri A, Dybkær K, Bøgsted M, Thrue CA, Hagedorn PH, Schmitz A, Bødker JS, Johnsen HE, Kauppinen S. Long Noncoding RNA Expression during Human B-Cell Development. PLoS One 2015; 10:e0138236. [PMID: 26394393 PMCID: PMC4578992 DOI: 10.1371/journal.pone.0138236] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 08/26/2015] [Indexed: 02/06/2023] Open
Abstract
Long noncoding RNAs (lncRNAs) have emerged as important regulators of diverse cellular processes, but their roles in the developing immune system are poorly understood. In this study, we analysed lncRNA expression during human B-cell development by array-based expression profiling of eleven distinct flow-sorted B-cell subsets, comprising pre-B1, pre-B2, immature, naive, memory, and plasma cells from bone marrow biopsies (n = 7), and naive, centroblast, centrocyte, memory, and plasmablast cells from tonsil tissue samples (n = 6), respectively. A remapping strategy was used to assign the array probes to 37630 gene-level probe sets, reflecting recent updates in genomic and transcriptomic databases, which enabled expression profiling of 19579 long noncoding RNAs, comprising 3947 antisense RNAs, 5277 lincRNAs, 7625 pseudogenes, and 2730 additional lncRNAs. As a first step towards inferring the functions of the identified lncRNAs in developing B-cells, we analysed their co-expression with well-characterized protein-coding genes, a method known as “guilt by association”. By using weighted gene co-expression network analysis, we identified 272 lincRNAs, 471 antisense RNAs, 376 pseudogene RNAs, and 64 lncRNAs within seven sub-networks associated with distinct stages of B-cell development, such as early B-cell development, B-cell proliferation, affinity maturation of antibody, and terminal differentiation. These data provide an important resource for future studies on the functions of lncRNAs in development of the adaptive immune response, and the pathogenesis of B-cell malignancies that originate from distinct B-cell subpopulations.
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Affiliation(s)
- Andreas Petri
- Center for RNA Medicine, Department of Clinical Medicine, Aalborg University, Copenhagen, Denmark
- Department of Haematology, Aalborg University Hospital, Aalborg, Denmark
| | - Karen Dybkær
- Department of Haematology, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
- Clinical Cancer Research Center, Aalborg University Hospital, Aalborg, Denmark
| | - Martin Bøgsted
- Department of Haematology, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
- Clinical Cancer Research Center, Aalborg University Hospital, Aalborg, Denmark
| | - Charlotte Albæk Thrue
- Center for RNA Medicine, Department of Clinical Medicine, Aalborg University, Copenhagen, Denmark
- Department of Haematology, Aalborg University Hospital, Aalborg, Denmark
| | - Peter H. Hagedorn
- Center for RNA Medicine, Department of Clinical Medicine, Aalborg University, Copenhagen, Denmark
- Department of Haematology, Aalborg University Hospital, Aalborg, Denmark
| | - Alexander Schmitz
- Department of Haematology, Aalborg University Hospital, Aalborg, Denmark
| | - Julie Støve Bødker
- Department of Haematology, Aalborg University Hospital, Aalborg, Denmark
| | - Hans Erik Johnsen
- Department of Haematology, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
- Clinical Cancer Research Center, Aalborg University Hospital, Aalborg, Denmark
| | - Sakari Kauppinen
- Center for RNA Medicine, Department of Clinical Medicine, Aalborg University, Copenhagen, Denmark
- Department of Haematology, Aalborg University Hospital, Aalborg, Denmark
- * E-mail:
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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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16
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Developmental Switch in the Transcriptional Activity of a Long-Range Regulatory Element. Mol Cell Biol 2015. [PMID: 26195822 DOI: 10.1128/mcb.00509-15] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Eukaryotic gene expression is often controlled by distant regulatory elements. In developing B lymphocytes, transcription is associated with V(D)J recombination at immunoglobulin loci. This process is regulated by remote cis-acting elements. At the immunoglobulin heavy chain (IgH) locus, the 3' regulatory region (3'RR) promotes transcription in mature B cells. This led to the notion that the 3'RR orchestrates the IgH locus activity at late stages of B cell maturation only. However, long-range interactions involving the 3'RR were detected in early B cells, but the functional consequences of these interactions were unknown. Here we show that not only does the 3'RR affect transcription at distant sites within the IgH variable region but also it conveys a transcriptional silencing activity on both sense and antisense transcription. The 3'RR-mediated silencing activity is switched off upon completion of VH-DJH recombination. Our findings reveal a developmentally controlled, stage-dependent shift in the transcriptional activity of a master regulatory element.
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Complete cis Exclusion upon Duplication of the Eμ Enhancer at the Immunoglobulin Heavy Chain Locus. Mol Cell Biol 2015; 35:2231-41. [PMID: 25896912 DOI: 10.1128/mcb.00294-15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Developing lymphocytes somatically diversify their antigen-receptor loci through V(D)J recombination. The process is associated with allelic exclusion, which results in monoallelic expression of an antigen receptor locus. Various cis-regulatory elements control V(D)J recombination in a developmentally regulated manner, but their role in allelic exclusion is still unclear. At the immunoglobulin heavy chain locus (IgH), the Eμ enhancer plays a critical role in V(D)J recombination. We generated a mouse line with a replacement mutation in the constant region of the locus that duplicates the Eμ enhancer and allows premature expression of the γ3 heavy chain. Strikingly, IgM expression was completely and specifically excluded in cis from the mutant allele. This cis exclusion recapitulated the main features of allelic exclusion, including differential exclusion of variable genes. Notably, sense and antisense transcription within the distal variable domain and distal V(H)-DJ(H) recombination were inhibited. cis exclusion was established and stably maintained despite an active endogenous Eμ enhancer. The data reveal the importance of the dynamic, developmental stage-dependent interplay between IgH locus enhancers and signaling in the induction and maintenance of allelic exclusion.
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18
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de Almeida CR, Hendriks RW, Stadhouders R. Dynamic Control of Long-Range Genomic Interactions at the Immunoglobulin κ Light-Chain Locus. Adv Immunol 2015; 128:183-271. [DOI: 10.1016/bs.ai.2015.07.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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20
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Insertion of an imprinted insulator into the IgH locus reveals developmentally regulated, transcription-dependent control of V(D)J recombination. Mol Cell Biol 2014; 35:529-43. [PMID: 25403489 DOI: 10.1128/mcb.00235-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The assembly of antigen receptor loci requires a developmentally regulated and lineage-specific recombination between variable (V), diversity (D), and joining (J) segments through V(D)J recombination. The process is regulated by accessibility control elements, including promoters, insulators, and enhancers. The IgH locus undergoes two recombination steps, D-J(H) and then V(H)-DJ(H), but it is unclear how the availability of the DJ(H) substrate could influence the subsequent V(H)-DJ(H) recombination step. The Eμ enhancer plays a critical role in V(D)J recombination and controls a set of sense and antisense transcripts. We epigenetically perturbed the early events at the IgH locus by inserting the imprinting control region (ICR) of the Igf2/H19 locus or a transcriptional insulator devoid of the imprinting function upstream of the Eμ enhancer. The insertions recapitulated the main epigenetic features of their endogenous counterparts, including differential DNA methylation and binding of CTCF/cohesins. Whereas the D-J(H) recombination step was unaffected, both the insulator insertions led to a severe impairment of V(H)-DJ(H) recombination. Strikingly, the inhibition of V(H)-DJ(H) recombination correlated consistently with a strong reduction of DJ(H) transcription and incomplete demethylation. Thus, developmentally regulated transcription following D-J(H) recombination emerges as an important mechanism through which the Eμ enhancer controls V(H)-DJ(H) recombination.
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21
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Birshtein BK. Epigenetic Regulation of Individual Modules of the immunoglobulin heavy chain locus 3' Regulatory Region. Front Immunol 2014; 5:163. [PMID: 24795714 PMCID: PMC4000994 DOI: 10.3389/fimmu.2014.00163] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 03/27/2014] [Indexed: 11/18/2022] Open
Abstract
The Igh locus undergoes an amazing array of DNA rearrangements and modifications during B cell development. During early stages, the variable region gene is constructed from constituent variable (V), diversity (D), and joining (J) segments (VDJ joining). B cells that successfully express an antibody can be activated, leading to somatic hypermutation (SHM) focused on the variable region, and class switch recombination (CSR), which substitutes downstream constant region genes for the originally used Cμ constant region gene. Many investigators, ourselves included, have sought to understand how these processes specifically target the Igh locus and avoid other loci and potential deleterious consequences of malignant transformation. Our laboratory has concentrated on a complex regulatory region (RR) that is located downstream of Cα, the most 3′ of the Igh constant region genes. The ~40 kb 3′ RR, which is predicted to serve as a downstream major regulator of the Igh locus, contains two distinct segments: an ~28 kb region comprising four enhancers, and an adjacent ~12 kb region containing multiple CTCF and Pax5 binding sites. Analysis of targeted mutations in mice by a number of investigators has concluded that the entire 3′ RR enhancer region is essential for SHM and CSR (but not for VDJ joining) and for high levels of expression of multiple isotypes. The CTCF/Pax5 binding region is a candidate for influencing VDJ joining early in B cell development and serving as a potential insulator of the Igh locus. Components of the 3′ RR are subject to a variety of epigenetic changes during B cell development, i.e., DNAse I hypersensitivity, histone modifications, and DNA methylation, in association with transcription factor binding. I propose that these changes provide a foundation by which regulatory elements in modules of the 3′ RR function by interacting with each other and with target sequences of the Igh locus.
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Affiliation(s)
- Barbara K Birshtein
- Department of Cell Biology, Albert Einstein College of Medicine , Bronx, NY , USA
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22
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Complete humanization of the mouse immunoglobulin loci enables efficient therapeutic antibody discovery. Nat Biotechnol 2014; 32:356-63. [PMID: 24633243 DOI: 10.1038/nbt.2825] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 01/15/2014] [Indexed: 02/01/2023]
Abstract
If immunized with an antigen of interest, transgenic mice with large portions of unrearranged human immunoglobulin loci can produce fully human antigen-specific antibodies; several such antibodies are in clinical use. However, technical limitations inherent to conventional transgenic technology and sequence divergence between the human and mouse immunoglobulin constant regions limit the utility of these mice. Here, using repetitive cycles of genome engineering in embryonic stem cells, we have inserted the entire human immunoglobulin variable-gene repertoire (2.7 Mb) into the mouse genome, leaving the mouse constant regions intact. These transgenic mice are viable and fertile, with an immune system resembling that of wild-type mice. Antigen immunization results in production of high-affinity antibodies with long human-like complementarity-determining region 3 (CDR3H), broad epitope coverage and strong signatures of somatic hypermutation. These mice provide a robust system for the discovery of therapeutic human monoclonal antibodies; as a surrogate readout of the human antibody response, they may also aid vaccine design efforts.
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23
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Almagro JC, Gilliland GL, Breden F, Scott JK, Sok D, Pauthner M, Reichert JM, Helguera G, Andrabi R, Mabry R, Bléry M, Voss JE, Laurén J, Abuqayyas L, Barghorn S, Ben-Jacob E, Crowe JE, Huston JS, Johnston SA, Krauland E, Lund-Johansen F, Marasco WA, Parren PWHI, Xu KY. Antibody engineering and therapeutics, The Annual Meeting of the Antibody Society: December 8-12, 2013, Huntington Beach, CA. MAbs 2014; 6:577-618. [PMID: 24589717 PMCID: PMC4011904 DOI: 10.4161/mabs.28421] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The 24th Antibody Engineering & Therapeutics meeting brought together a broad range of participants who were updated on the latest advances in antibody research and development. Organized by IBC Life Sciences, the gathering is the annual meeting of The Antibody Society, which serves as the scientific sponsor. Preconference workshops on 3D modeling and delineation of clonal lineages were featured, and the conference included sessions on a wide variety of topics relevant to researchers, including systems biology; antibody deep sequencing and repertoires; the effects of antibody gene variation and usage on antibody response; directed evolution; knowledge-based design; antibodies in a complex environment; polyreactive antibodies and polyspecificity; the interface between antibody therapy and cellular immunity in cancer; antibodies in cardiometabolic medicine; antibody pharmacokinetics, distribution and off-target toxicity; optimizing antibody formats for immunotherapy; polyclonals, oligoclonals and bispecifics; antibody discovery platforms; and antibody-drug conjugates.
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Affiliation(s)
| | | | | | | | - Devin Sok
- The Scripps Research Institute; La Jolla, CA USA
| | | | | | - Gustavo Helguera
- CONICET; Laboratorio Biotecnología Farmacéutica; Instituto de Biología y Medicina Experimental, IBYME; Ciudad Autónoma de Buenos Aires, Argentina
| | | | | | | | - James E Voss
- The Scripps Research Institute; La Jolla, CA USA
| | - Juha Laurén
- Regeneron Pharmaceuticals, Inc.; Tarrytown, NY USA
| | | | | | | | - James E Crowe
- Vanderbilt University Medical Center, Nashville, TN, USA
| | | | | | | | | | | | | | - Kai Y Xu
- University of Maryland; Baltimore, MD USA
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24
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Choi NM, Feeney AJ. CTCF and ncRNA Regulate the Three-Dimensional Structure of Antigen Receptor Loci to Facilitate V(D)J Recombination. Front Immunol 2014; 5:49. [PMID: 24575097 PMCID: PMC3920468 DOI: 10.3389/fimmu.2014.00049] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 01/28/2014] [Indexed: 01/15/2023] Open
Abstract
At both the immunoglobulin heavy and kappa light chain loci, there are >100 functional variable (V) genes spread over >2 Mb that must move into close proximity in 3D space to the (D)J genes to create a diverse repertoire of antibodies. Similar events take place at the T cell receptor (TCR) loci to create a wide repertoire of TCRs. In this review, we will discuss the role of CTCF in forming rosette-like structures at the antigen receptor (AgR) loci, and the varied roles it plays in alternately facilitating and repressing V(D)J rearrangements. In addition, non-coding RNAs, also known as germline transcription, can shape the 3D configuration of the Igh locus, and presumably that of the other AgR loci. At the Igh locus, this could occur by gathering the regions being transcribed in the VH locus into the same transcription factory where Iμ is being transcribed. Since the Iμ promoter, Eμ, is adjacent to the DJH rearrangement to which one V gene will ultimately rearrange, the process of germline transcription itself, prominent in the distal half of the VH locus, may play an important and direct role in locus compaction. Finally, we will discuss the impact of the transcriptional and epigenetic landscape of the Igh locus on VH gene rearrangement frequencies.
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Affiliation(s)
- Nancy M Choi
- Department of Immunology and Microbial Science, The Scripps Research Institute , La Jolla, CA , USA
| | - Ann J Feeney
- Department of Immunology and Microbial Science, The Scripps Research Institute , La Jolla, CA , USA
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25
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Rouaud P, Vincent-Fabert C, Saintamand A, Fiancette R, Marquet M, Robert I, Reina-San-Martin B, Pinaud E, Cogné M, Denizot Y. The IgH 3' regulatory region controls somatic hypermutation in germinal center B cells. ACTA ACUST UNITED AC 2013; 210:1501-7. [PMID: 23825188 PMCID: PMC3727322 DOI: 10.1084/jem.20130072] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Somatic hypermutation in variable heavy chain rearranged regions is abrogated in the absence of the 3′ regulatory region enhancer, whereas transcription rate in the Ig heavy chain is only partially reduced. Interactions with cognate antigens recruit activated B cells into germinal centers where they undergo somatic hypermutation (SHM) in V(D)J exons for the generation of high-affinity antibodies. The contribution of IgH transcriptional enhancers in SHM is unclear. The Eμ enhancer upstream of Cμ has a marginal role, whereas the influence of the IgH 3′ regulatory region (3′RR) enhancers (hs3a, hs1,2, hs3b, and hs4) is controversial. To clarify the latter issue, we analyzed mice lacking the whole 30-kb extent of the IgH 3′RR. We show that SHM in VH rearranged regions is almost totally abrogated in 3′RR-deficient mice, whereas the simultaneous Ig heavy chain transcription rate is only partially reduced. In contrast, SHM in κ light chain genes remains unaltered, acquitting for any global SHM defect in our model. Beyond class switch recombination, the IgH 3′RR is a central element that controls heavy chain accessibility to activation-induced deaminase modifications including SHM.
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Affiliation(s)
- Pauline Rouaud
- Centre National de la Recherche Scientifique (CNRS) UMR 7276, Université de Limoges, 87025 Limoges, France
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26
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Merkenschlager M, Odom DT. CTCF and cohesin: linking gene regulatory elements with their targets. Cell 2013; 152:1285-97. [PMID: 23498937 DOI: 10.1016/j.cell.2013.02.029] [Citation(s) in RCA: 265] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 02/11/2013] [Accepted: 02/12/2013] [Indexed: 12/11/2022]
Abstract
Current epigenomics approaches have facilitated the genome-wide identification of regulatory elements based on chromatin features and transcriptional regulator binding and have begun to map long-range interactions between regulatory elements and their targets. Here, we focus on the emerging roles of CTCF and the cohesin in coordinating long-range interactions between regulatory elements. We discuss how species-specific transposable elements may influence such interactions by remodeling the CTCF binding repertoire and suggest that cohesin's association with enhancers, promoters, and sites defined by CTCF binding has the potential to form developmentally regulated networks of long-range interactions that reflect and promote cell-type-specific transcriptional programs.
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Affiliation(s)
- Matthias Merkenschlager
- Lymphocyte Development Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK.
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27
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Stubbington MJT, Corcoran AE. Non-coding transcription and large-scale nuclear organisation of immunoglobulin recombination. Curr Opin Genet Dev 2013; 23:81-8. [PMID: 23434028 DOI: 10.1016/j.gde.2013.01.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 01/07/2013] [Indexed: 02/01/2023]
Abstract
The enormous antigen receptor loci in lymphocytes are a paradigm of dynamic nuclear organisation, which is integral to their need to move extensively in 3D space to achieve distal gene synapse for V(D)J recombination and allelic exclusion. The loci undergo extensive 3D looping to bring distal genes together, controlled by several tissue-specific and ubiquitous factors, but how these factors achieve looping, synapsis and V(D)J recombination has been a mystery. Now several studies provide evidence that non-coding transcription, often proposed to play a role, is indeed an important driver, and furthermore has a specific nuclear destination for recombination. Both local transcription-independent looping and longer range factor-mediated transcription-dependent looping play separate roles in altering AgR architecture to enable V(D)J recombination.
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Affiliation(s)
- Michael J T Stubbington
- Nuclear Dynamics Laboratory, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
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28
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Selimyan R, Gerstein RM, Ivanova I, Precht P, Subrahmanyam R, Perlot T, Alt FW, Sen R. Localized DNA demethylation at recombination intermediates during immunoglobulin heavy chain gene assembly. PLoS Biol 2013; 11:e1001475. [PMID: 23382652 PMCID: PMC3558432 DOI: 10.1371/journal.pbio.1001475] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 12/14/2012] [Indexed: 12/23/2022] Open
Abstract
The dynamics of DNA methylation during the complex genomic rearrangement of antigen receptor genes in developing B lymphocytes reveal localized demethylation of the first recombination product that may serve as a mark necessary for the second step of rearrangement. Multiple epigenetic marks have been proposed to contribute to the regulation of antigen receptor gene assembly via V(D)J recombination. Here we provide a comprehensive view of DNA methylation at the immunoglobulin heavy chain (IgH) gene locus prior to and during V(D)J recombination. DNA methylation did not correlate with the histone modification state on unrearranged alleles, indicating that these epigenetic marks were regulated independently. Instead, pockets of tissue-specific demethylation were restricted to DNase I hypersensitive sites within this locus. Though unrearranged diversity (DH) and joining (JH) gene segments were methylated, DJH junctions created after the first recombination step were largely demethylated in pro-, pre-, and mature B cells. Junctional demethylation was highly localized, B-lineage-specific, and required an intact tissue-specific enhancer, Eμ. We propose that demethylation occurs after the first recombination step and may mark the junction for secondary recombination. DNA methylation at CpG dinucleotides is implicated in the regulation of gene expression in mammals. However, the regulation of DNA methylation itself is less clear despite recent advances in identifying enzymes that add or remove methyl groups. We have investigated the dynamics of DNA methylation during genome rearrangements that assemble antigen receptor genes in developing B lymphocytes to determine whether methylation status correlates with rearrangement potential. Two recombination events generate immunoglobulin heavy chain (IgH) genes. The first step brings together diversity (DH) and joining (JH) gene segments to produce DJH junctions. We show that both gene segments are methylated prior to rearrangement, whereas the DJH product is demethylated. DJH junctional demethylation is tissue-specific and requires an enhancer, Eμ, located within the IgH locus. The latter observations indicate that localized demethylation of the DJH junction occurs after the first recombination step and thus does not guide this first step of IgH gene assembly. Our working hypothesis is that recombination induces demethylation of recombinant product and may mark the junction for the second step of IgH rearrangement, juxtaposition of variable (VH) gene segments to rearranged DJH products to produce fully recombined V(D)J alleles.
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Affiliation(s)
- Roza Selimyan
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Rachel M. Gerstein
- Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Irina Ivanova
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Patricia Precht
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Ramesh Subrahmanyam
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Thomas Perlot
- The Howard Hughes Medical Institute, The Children's Hospital, Immune Disease Institute and Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Frederick W. Alt
- The Howard Hughes Medical Institute, The Children's Hospital, Immune Disease Institute and Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ranjan Sen
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
- * E-mail:
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29
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Subrahmanyam R, Du H, Ivanova I, Chakraborty T, Ji Y, Zhang Y, Alt FW, Schatz DG, Sen R. Localized epigenetic changes induced by DH recombination restricts recombinase to DJH junctions. Nat Immunol 2012; 13:1205-12. [PMID: 23104096 PMCID: PMC3685187 DOI: 10.1038/ni.2447] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 09/07/2012] [Indexed: 12/11/2022]
Abstract
Genes encoding immunoglobulin heavy chains (Igh) are assembled by rearrangement of variable (V(H)), diversity (D(H)) and joining (J(H)) gene segments. Three critical constraints govern V(H) recombination. These include timing (V(H) recombination follows D(H) recombination), precision (V(H) gene segments recombine only to DJ(H) junctions) and allele specificity (V(H) recombination is restricted to DJ(H)-recombined alleles). Here we provide a model for these universal features of V(H) recombination. Analyses of DJ(H)-recombined alleles showed that DJ(H) junctions were selectively epigenetically marked, became nuclease sensitive and bound RAG recombinase proteins, which thereby permitted D(H)-associated recombination signal sequences to initiate the second step of Igh gene assembly. We propose that V(H) recombination is precise, because these changes did not extend to germline D(H) segments located 5' of the DJ(H) junction.
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Affiliation(s)
- Ramesh Subrahmanyam
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, US National Institutes of Health, Baltimore, Maryland, USA
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30
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DNA-binding factor CTCF and long-range gene interactions in V(D)J recombination and oncogene activation. Blood 2012; 119:6209-18. [DOI: 10.1182/blood-2012-03-402586] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Abstract
Regulation of V(D)J recombination events at immunoglobulin (Ig) and T-cell receptor loci in lymphoid cells is complex and achieved via changes in substrate accessibility. Various studies over the last year have identified the DNA-binding zinc-finger protein CCCTC-binding factor (CTCF) as a crucial regulator of long-range chromatin interactions. CTCF often controls specific interactions by preventing inappropriate communication between neighboring regulatory elements or independent chromatin domains. Although recent gene targeting experiments demonstrated that the presence of the CTCF protein is not required for the process of V(D)J recombination per se, CTCF turned out to be essential to control order, lineage specificity and to balance the Ig V gene repertoire. Moreover, CTCF was shown to restrict activity of κ enhancer elements to the Ig κ locus. In this review, we discuss CTCF function in the regulation of V(D)J recombination on the basis of established knowledge on CTCF-mediated chromatin loop domains in various other loci, including the imprinted H19-Igf2 locus as well as the complex β-globin, MHC class II and IFN-γ loci. Moreover, we discuss that loss of CTCF-mediated restriction of enhancer activity may well contribute to oncogenic activation, when in chromosomal translocations Ig enhancer elements and oncogenes appear in a novel genomic context.
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31
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Shrimali S, Srivastava S, Varma G, Grinberg A, Pfeifer K, Srivastava M. An ectopic CTCF-dependent transcriptional insulator influences the choice of Vβ gene segments for VDJ recombination at TCRβ locus. Nucleic Acids Res 2012; 40:7753-65. [PMID: 22718969 PMCID: PMC3439925 DOI: 10.1093/nar/gks556] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Insulators regulate transcription as they modulate the interactions between enhancers and promoters by organizing the chromatin into distinct domains. To gain better understanding of the nature of chromatin domains defined by insulators, we analyzed the ability of an insulator to interfere in VDJ recombination, a process that is critically dependent on long-range interactions between diverse types of cis-acting DNA elements. A well-established CTCF-dependent transcriptional insulator, H19 imprint control region (H19-ICR), was inserted in the mouse TCRβ locus by genetic manipulation. Analysis of the mutant mice demonstrated that the insulator retains its CTCF and position-dependent enhancer-blocking potential in this heterologous context in vivo. Remarkably, the inserted H19-ICR appears to have the ability to modulate cis-DNA interactions between recombination signal sequence elements of the TCRβ locus leading to a dramatically altered usage of Vβ segments for Vβ-to-DβJβ recombination in the mutant mice. This reveals a novel ability of CTCF to govern long range cis-DNA interactions other than enhancer-promoter interactions and suggests that CTCF-dependent insulators may play a diverse and complex role in genome organization beyond transcriptional control. Our functional analysis of mutated TCRβ locus supports the emerging role of CTCF in governing VDJ recombination.
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Affiliation(s)
- Sweety Shrimali
- National Institute of Immunology, Aruna Asaf Ali Road, New Delhi 110067, India
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32
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Seitan VC, Krangel MS, Merkenschlager M. Cohesin, CTCF and lymphocyte antigen receptor locus rearrangement. Trends Immunol 2012; 33:153-9. [PMID: 22440186 PMCID: PMC3352889 DOI: 10.1016/j.it.2012.02.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 02/14/2012] [Accepted: 02/14/2012] [Indexed: 11/20/2022]
Abstract
The somatic recombination of lymphocyte antigen receptor loci is integral to lymphocyte differentiation and adaptive immunity. Here we review the relation of this highly choreographed process with the zinc finger protein CTCF and with cohesin, a protein complex best known for its essential functions in post-replicative DNA repair and chromosome segregation during the cell cycle. At lymphocyte antigen receptor loci, CTCF and cohesin shape long-range interactions and contribute to V(D)J recombination by facilitating lineage- and developmental-stage-specific transcription and accessibility.
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Affiliation(s)
- Vlad C Seitan
- Lymphocyte Development Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Michael S Krangel
- Department of Immunology, Duke University Medical Center, Durham NC, USA
| | - Matthias Merkenschlager
- Lymphocyte Development Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
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33
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Chaumeil J, Skok JA. The role of CTCF in regulating V(D)J recombination. Curr Opin Immunol 2012; 24:153-9. [PMID: 22424610 DOI: 10.1016/j.coi.2012.01.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 01/05/2012] [Accepted: 01/06/2012] [Indexed: 11/17/2022]
Abstract
V(D)J recombination in B and T cells is required for the generation of receptors with a broad spectrum of specificity to foreign antigen. A total number of three immunoglobulin (Ig) and four T cell receptor (Tcr) loci can be targeted by the recombinase enzyme (RAG1/2) in a defined series of recombination events, which drive the progression of B and T cell development. This process is regulated at multiple levels to ensure lineage specific, ordered rearrangement and allelic exclusion. One key component of this is modulation of chromatin looping and locus contraction, which is important in bringing widely separated gene segments into close contact with each other to enable synapse formation for lineage and stage specific V gene rearrangement [2,3,4(•),5,6(•)]. Recent studies provide new insight into looping and its role in these processes. In this review we focus on the contribution of the 11 zinc finger nuclear protein, CTCF, in mediating loop formation and conformational changes that are important for the regulation of Ig and Tcr rearrangement.
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Affiliation(s)
- Julie Chaumeil
- Department of Pathology, New York University School of Medicine, 550 First Avenue, MSB 599, New York, NY 10016, USA
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34
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Berkowska MA, van der Burg M, van Dongen JJM, van Zelm MC. Checkpoints of B cell differentiation: visualizing Ig-centric processes. Ann N Y Acad Sci 2012; 1246:11-25. [PMID: 22236426 DOI: 10.1111/j.1749-6632.2011.06278.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The generation of antibody responses and B cell memory can only take place following multiple steps of differentiation. Key molecular processes during precursor B cell differentiation in bone marrow generate unique antibodies. These antibodies are further optimized via molecular modifications during immune responses in peripheral lymphoid organs. Multiple checkpoints ensure proper differentiation of precursor and mature B lymphocytes. Many of these checkpoints have been found disrupted in patients with a primary immunodeficiency. Based on studies in these patients and in mouse models, new insights have been generated in B cell differentiation and antibody responses. Still, in many patients with impaired antibody formation, it remains unclear how B cells are affected. In this perspective, we present 11 critical processes in B cell differentiation. We discuss how defects in these processes can result in impaired checkpoint selection and how they can be visualized in healthy subjects and patients with immunodeficiency or other immunological disease.
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Affiliation(s)
- Magdalena A Berkowska
- Department of Immunology, Erasmus MC, University Medical Center, Rotterdam, the Netherlands
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35
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Volpi SA, Verma-Gaur J, Hassan R, Ju Z, Roa S, Chatterjee S, Werling U, Hou H, Will B, Steidl U, Scharff M, Edelman W, Feeney AJ, Birshtein BK. Germline deletion of Igh 3' regulatory region elements hs 5, 6, 7 (hs5-7) affects B cell-specific regulation, rearrangement, and insulation of the Igh locus. THE JOURNAL OF IMMUNOLOGY 2012; 188:2556-66. [PMID: 22345664 DOI: 10.4049/jimmunol.1102763] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Regulatory elements located within an ∼28-kb region 3' of the Igh gene cluster (3' regulatory region) are required for class switch recombination and for high levels of IgH expression in plasma cells. We previously defined novel DNase I hypersensitive sites (hs) 5, 6, 7 immediately downstream of this region. The hs 5-7 region (hs5-7) contains a high density of binding sites for CCCTC-binding factor (CTCF), a zinc finger protein associated with mammalian insulator activity, and is an anchor for interactions with CTCF sites flanking the D(H) region. To test the function of hs5-7, we generated mice with an 8-kb deletion encompassing all three hs elements. B cells from hs5-7 knockout (KO) (hs5-7KO) mice showed a modest increase in expression of the nearest downstream gene. In addition, Igh alleles in hs5-7KO mice were in a less contracted configuration compared with wild-type Igh alleles and showed a 2-fold increase in the usage of proximal V(H)7183 gene families. Hs5-7KO mice were essentially indistinguishable from wild-type mice in B cell development, allelic regulation, class switch recombination, and chromosomal looping. We conclude that hs5-7, a high-density CTCF-binding region at the 3' end of the Igh locus, impacts usage of V(H) regions as far as 500 kb away.
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Affiliation(s)
- Sabrina A Volpi
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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36
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Feeney AJ, Verma-Gaur J. CTCF-cohesin complex: architect of chromatin structure regulates V(D)J rearrangement. Cell Res 2012; 22:280-2. [PMID: 22105486 PMCID: PMC3271585 DOI: 10.1038/cr.2011.188] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Ann J Feeney
- The Scripps Research Institute, Department of Immunology and Microbial Science, IMM22, 10550 N. Torrey Pines Rd., La Jolla, CA 92037, USA.
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37
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Rouaud P, Vincent-Fabert C, Fiancette R, Cogné M, Pinaud E, Denizot Y. Enhancers located in heavy chain regulatory region (hs3a, hs1,2, hs3b, and hs4) are dispensable for diversity of VDJ recombination. J Biol Chem 2012; 287:8356-60. [PMID: 22270371 DOI: 10.1074/jbc.m112.341024] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
V(D)J recombination occurs during the antigen-independent early steps of B-cell ontogeny. Multiple IgH cis-regulatory elements control B-cell ontogeny. IGCR1 (intergenic control region 1), the DQ52 promoter/enhancer, and the intronic Emu enhancer, all three located upstream of Cmu, have important roles during V(D)J recombination, whereas there is no clue about a role of the IgH regulatory region (RR) encompassing the four transcriptional enhancers hs3a, hs1,2, hs3b, and hs4 during these early stages. To clarify the role of the RR in V(D)J recombination, we totally deleted it in the mouse genome. Here, we show that V(D)J recombination is unaffected by the complete absence of the IgH RR, highlighting that this region only orchestrates IgH locus activity during the late stages of B-cell differentiation. In contrast, the earliest antigen-independent steps of B-cell ontogeny would be under the control of only the upstream Cmu elements of the locus.
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Affiliation(s)
- Pauline Rouaud
- UMR CNRS 7276, Centre National de la Recherche Scientifique, Université de Limoges, 87025 Limoges Cedex, France
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38
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Bossen C, Mansson R, Murre C. Chromatin topology and the regulation of antigen receptor assembly. Annu Rev Immunol 2012; 30:337-56. [PMID: 22224771 DOI: 10.1146/annurev-immunol-020711-075003] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
During an organism's ontogeny and in the adult, each B and T lymphocyte generates a unique antigen receptor, thereby creating the organism's ability to respond to a vast number of different antigens. The antigen receptor loci are organized into distinct regions that contain multiple variable (V), diversity (D), and/or joining (J) and constant (C) coding elements that are scattered across large genomic regions. In this review, we discuss the epigenetic modifications that take place in the different antigen receptor loci, the chromatin structure adopted by the antigen receptor loci to allow recombination of elements separated by large genomic distances, and the relationship between epigenetics and chromatin structure and how they relate to the generation of antigen receptor diversity.
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Affiliation(s)
- Claudia Bossen
- Division of Biological Sciences, Department of Molecular Biology, University of California at San Diego, La Jolla, California 92093-0377, USA
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39
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Ribeiro de Almeida C, Stadhouders R, de Bruijn MJW, Bergen IM, Thongjuea S, Lenhard B, van Ijcken W, Grosveld F, Galjart N, Soler E, Hendriks RW. The DNA-binding protein CTCF limits proximal Vκ recombination and restricts κ enhancer interactions to the immunoglobulin κ light chain locus. Immunity 2011; 35:501-13. [PMID: 22035845 DOI: 10.1016/j.immuni.2011.07.014] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 06/30/2011] [Accepted: 07/27/2011] [Indexed: 10/15/2022]
Abstract
Regulation of immunoglobulin (Ig) V(D)J gene rearrangement is dependent on higher-order chromatin organization. Here, we studied the in vivo function of the DNA-binding zinc-finger protein CTCF, which regulates interactions between enhancers and promoters. By conditional deletion of the Ctcf gene in the B cell lineage, we demonstrate that loss of CTCF allowed Ig heavy chain recombination, but pre-B cell proliferation and differentiation was severely impaired. In the absence of CTCF, the Igκ light chain locus showed increased proximal and reduced distal Vκ usage. This was associated with enhanced proximal Vκ and reduced Jκ germline transcription. Chromosome conformation capture experiments demonstrated that CTCF limits interactions of the Igκ enhancers with the proximal V(κ) gene region and prevents inappropriate interactions between these strong enhancers and elements outside the Igκ locus. Thus, although Ig gene recombination can occur in the absence of CTCF, it is a critical factor determining Vκ segment choice for recombination.
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Affiliation(s)
- Claudia Ribeiro de Almeida
- Department of Pulmonary Medicine, Erasmus MC Rotterdam, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands
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40
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Guo C, Gerasimova T, Hao H, Ivanova I, Chakraborty T, Selimyan R, Oltz EM, Sen R. Two forms of loops generate the chromatin conformation of the immunoglobulin heavy-chain gene locus. Cell 2011; 147:332-43. [PMID: 21982154 DOI: 10.1016/j.cell.2011.08.049] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 04/26/2011] [Accepted: 08/26/2011] [Indexed: 10/16/2022]
Abstract
The immunoglobulin heavy-chain (IgH) gene locus undergoes radial repositioning within the nucleus and locus contraction in preparation for gene recombination. We demonstrate that IgH locus conformation involves two levels of chromosomal compaction. At the first level, the locus folds into several multilooped domains. One such domain at the 3' end of the locus requires an enhancer, Eμ; two other domains at the 5' end are Eμ independent. At the second level, these domains are brought into spatial proximity by Eμ-dependent interactions with specific sites within the V(H) region. Eμ is also required for radial repositioning of IgH alleles, indicating its essential role in large-scale chromosomal movements in developing lymphocytes. Our observations provide a comprehensive view of the conformation of IgH alleles in pro-B cells and the mechanisms by which it is established.
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Affiliation(s)
- Changying Guo
- Gene Regulation Section, Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD 21224, USA
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41
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Ju Z, Chatterjee S, Birshtein BK. Interaction between the immunoglobulin heavy chain 3' regulatory region and the IgH transcription unit during B cell differentiation. Mol Immunol 2011; 49:297-303. [PMID: 21945019 DOI: 10.1016/j.molimm.2011.08.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 08/26/2011] [Accepted: 08/30/2011] [Indexed: 11/29/2022]
Abstract
The immunoglobulin heavy (Igh) chain locus is subject to precisely regulated processes, such as variable region gene formation through recombination of variable (V(H)), diversity (D(H)), and joining (J(H)) segments, class switching and somatic hypermutation. The 3' regulatory region (3' RR) is a key regulator of the Igh locus, and, as revealed by deletions in mouse plasma cell lines and mice, is required for IgH expression as well as class switching. One of the mechanisms by which the 3' RR regulates its targets is through long-range physical interactions. Such interactions between elements of the 3' RR and a target site in the IgH transcription unit have been detected in plasma cells, and in resting and switching B cells, where they have been associated with IgH expression and class switching, respectively. Here, we report that lentiviral shRNA knockdown of transcription factors, CTCF, Oct-2, or OBF-1/OCA-B, had no discernible defects in loop formation or H chain expression in plasma cells. J(H)-3' RR interactions in pre-B cell lines were specifically associated with IgH expression. J(H)-3' RR interactions were not detected in either Pax5-deficient or RAG-deficient pro-B cells, but were apparent in an Abelson-derived pro-B cell line. These observations imply that the 3' RR has different loop interactions with target Igh sequences at different stages of B cell development and Igh regulation.
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Affiliation(s)
- Zhongliang Ju
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY, USA
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42
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Guo C, Yoon HS, Franklin A, Jain S, Ebert A, Cheng HL, Hansen E, Despo O, Bossen C, Vettermann C, Bates JG, Richards N, Myers D, Patel H, Gallagher M, Schlissel MS, Murre C, Busslinger M, Giallourakis CC, Alt FW. CTCF-binding elements mediate control of V(D)J recombination. Nature 2011; 477:424-30. [PMID: 21909113 PMCID: PMC3342812 DOI: 10.1038/nature10495] [Citation(s) in RCA: 211] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 07/18/2011] [Indexed: 12/14/2022]
Abstract
Immunoglobulin heavy chain (IgH) variable region exons are assembled from V(H), D and J(H) gene segments in developing B lymphocytes. Within the 2.7-megabase mouse Igh locus, V(D)J recombination is regulated to ensure specific and diverse antibody repertoires. Here we report in mice a key Igh V(D)J recombination regulatory region, termed intergenic control region 1 (IGCR1), which lies between the V(H) and D clusters. Functionally, IGCR1 uses CTCF looping/insulator factor-binding elements and, correspondingly, mediates Igh loops containing distant enhancers. IGCR1 promotes normal B-cell development and balances antibody repertoires by inhibiting transcription and rearrangement of D(H)-proximal V(H) gene segments and promoting rearrangement of distal V(H) segments. IGCR1 maintains ordered and lineage-specific V(H)(D)J(H) recombination by suppressing V(H) joining to D segments not joined to J(H) segments, and V(H) to DJ(H) joins in thymocytes, respectively. IGCR1 is also required for feedback regulation and allelic exclusion of proximal V(H)-to-DJ(H) recombination. Our studies elucidate a long-sought Igh V(D)J recombination control region and indicate a new role for the generally expressed CTCF protein.
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MESH Headings
- Animals
- B-Lymphocytes/cytology
- B-Lymphocytes/metabolism
- CCCTC-Binding Factor
- Cell Lineage/genetics
- Chromosomes, Mammalian/genetics
- Chromosomes, Mammalian/metabolism
- DNA, Intergenic/genetics
- Enhancer Elements, Genetic/genetics
- Feedback, Physiological
- Gene Rearrangement, B-Lymphocyte, Heavy Chain/genetics
- Germ Cells/metabolism
- Immunoglobulin Heavy Chains/genetics
- Immunoglobulin Variable Region/genetics
- Mice
- Mutation/genetics
- Recombination, Genetic/genetics
- Regulatory Sequences, Nucleic Acid/genetics
- Repressor Proteins/metabolism
- Thymus Gland/cytology
- Transcription, Genetic/genetics
- VDJ Exons/genetics
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Affiliation(s)
- Chunguang Guo
- Howard Hughes Medical Institute, The Children's Hospital, The Immune Disease Institute, Department of Genetics, Harvard Medical School, 300 Longwood Avenue, Boston, Massachusetts 02115, USA
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43
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Zhu C, Feng W, Weedon J, Hua P, Stefanov D, Ohta Y, Flajnik MF, Hsu E. The multiple shark Ig H chain genes rearrange and hypermutate autonomously. THE JOURNAL OF IMMUNOLOGY 2011; 187:2492-501. [PMID: 21804022 DOI: 10.4049/jimmunol.1101671] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Sharks and skates are representatives of the earliest vertebrates with an immune system based on V(D)J rearrangement. They possess a unique Ig gene organization consisting of 15 to >50 individual IgM loci, each with one VH, two DH, one JH, and one set of constant region exons. The present study attempts to understand how multiple Ig genes are regulated with respect to rearrangement initiation and to targeting during somatic hypermutation. The linkage of three single-copy IgH genes was determined, and single-cell genomic PCR studies in a neonatal animal were used to examine any relationship between relative gene position and likelihood of rearrangement. Our results show that one to three IgH genes are activated independently of linkage or allelic position and the data best fit with a probability model based on the hypothesis that V(D)J rearrangement occurs as a sequence of trials within the B cell. In the neonatal cell set, two closely related IgH, G2A, and G2B, rearranged at similar frequencies, and their membrane forms were expressed at similar levels, like in other young animals. However, older animals displayed a bias in favor of the G2A isotype, which suggests that although rearrangement at G2A and G2B was randomly initiated during primary repertoire generation, the two very similar IgM sequences appear to be differentially expressed with age and exposure to Ag. We performed genomic single-cell PCR on B cells from an immunized individual to study activation-induced cytidine deaminase targeting and found that hypermutation, like V(D)J rearrangement, occurred independently among the many shark IgH.
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Affiliation(s)
- Catherine Zhu
- Department of Physiology and Pharmacology, State University of New York Health Science Center at Brooklyn, Brooklyn, NY 11203, USA
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44
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Abstract
Cells of the immune system are generated through a developmental cascade that begins in haematopoietic stem cells. During this process, gene expression patterns are programmed in a series of stages that bring about the restriction of cell potential, ultimately leading to the formation of specialized innate immune cells and mature lymphocytes that express antigen receptors. These events involve the regulation of both gene expression and DNA recombination, mainly through the control of chromatin accessibility. In this Review, we describe the epigenetic changes that mediate this complex differentiation process and try to understand the logic of the programming mechanism.
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45
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Degner SC, Verma-Gaur J, Wong TP, Bossen C, Iverson GM, Torkamani A, Vettermann C, Lin YC, Ju Z, Schulz D, Murre CS, Birshtein BK, Schork NJ, Schlissel MS, Riblet R, Murre C, Feeney AJ. CCCTC-binding factor (CTCF) and cohesin influence the genomic architecture of the Igh locus and antisense transcription in pro-B cells. Proc Natl Acad Sci U S A 2011; 108:9566-71. [PMID: 21606361 PMCID: PMC3111298 DOI: 10.1073/pnas.1019391108] [Citation(s) in RCA: 167] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Compaction and looping of the ~2.5-Mb Igh locus during V(D)J rearrangement is essential to allow all V(H) genes to be brought in proximity with D(H)-J(H) segments to create a diverse antibody repertoire, but the proteins directly responsible for this are unknown. Because CCCTC-binding factor (CTCF) has been demonstrated to be involved in long-range chromosomal interactions, we hypothesized that CTCF may promote the contraction of the Igh locus. ChIP sequencing was performed on pro-B cells, revealing colocalization of CTCF and Rad21 binding at ~60 sites throughout the V(H) region and 2 other sites within the Igh locus. These numerous CTCF/cohesin sites potentially form the bases of the multiloop rosette structures at the Igh locus that compact during Ig heavy chain rearrangement. To test whether CTCF was involved in locus compaction, we used 3D-FISH to measure compaction in pro-B cells transduced with CTCF shRNA retroviruses. Reduction of CTCF binding resulted in a decrease in Igh locus compaction. Long-range interactions within the Igh locus were measured with the chromosomal conformation capture assay, revealing direct interactions between CTCF sites 5' of DFL16 and the 3' regulatory region, and also the intronic enhancer (Eμ), creating a D(H)-J(H)-Eμ-C(H) domain. Knockdown of CTCF also resulted in the increase of antisense transcription throughout the D(H) region and parts of the V(H) locus, suggesting a widespread regulatory role for CTCF. Together, our findings demonstrate that CTCF plays an important role in the 3D structure of the Igh locus and in the regulation of antisense germline transcription and that it contributes to the compaction of the Igh locus.
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MESH Headings
- Animals
- Binding Sites/genetics
- Blotting, Western
- CCCTC-Binding Factor
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Cell Line
- Cells, Cultured
- Chromatin Immunoprecipitation
- Chromosomal Proteins, Non-Histone/genetics
- Chromosomal Proteins, Non-Histone/metabolism
- DNA, Antisense/genetics
- DNA-Binding Proteins
- Enhancer Elements, Genetic/genetics
- Immunoglobulin Heavy Chains/genetics
- Immunoglobulin Heavy Chains/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Phosphoproteins/genetics
- Phosphoproteins/metabolism
- Precursor Cells, B-Lymphoid/metabolism
- Protein Binding
- RNA Interference
- RNA, Antisense/genetics
- Repressor Proteins/genetics
- Repressor Proteins/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Transcription, Genetic
- Cohesins
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Affiliation(s)
- Stephanie C. Degner
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037
| | - Jiyoti Verma-Gaur
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037
| | - Timothy P. Wong
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037
| | - Claudia Bossen
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093
| | | | - Ali Torkamani
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, and The Scripps Translational Science Institute, La Jolla, CA 92037
| | - Christian Vettermann
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720; and
| | - Yin C. Lin
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093
| | - Zhongliang Ju
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Danae Schulz
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720; and
| | - Caroline S. Murre
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093
| | - Barbara K. Birshtein
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Nicholas J. Schork
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, and The Scripps Translational Science Institute, La Jolla, CA 92037
| | - Mark S. Schlissel
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720; and
| | - Roy Riblet
- Torrey Pines Institute for Molecular Studies, San Diego, CA 92121
| | - Cornelis Murre
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093
| | - Ann J. Feeney
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037
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Feeney AJ. Epigenetic regulation of antigen receptor gene rearrangement. Curr Opin Immunol 2011; 23:171-7. [PMID: 21216580 PMCID: PMC3073619 DOI: 10.1016/j.coi.2010.12.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 12/14/2010] [Accepted: 12/14/2010] [Indexed: 01/04/2023]
Abstract
Recent studies of the regulation of antigen receptor rearrangement have revealed several completely new levels of control. Not only do antigen receptor loci undergo changes in histone modifications as they become accessible for recombination, but also the number of different histone modifications and the variation at different parts of each receptor locus reveal great complexity. RAG2 is now known to bind to one of these histone modifications, H3K4me3, and this targets the initial RAG binding events to the J genes. The large megabase receptor loci undergo 3D changes in their structure during rearrangement, and receptor loci move throughout the nucleus, transiently binding to heterochromatin, and transiently pairing with each other. RAG-mediated DNA breaks promote some of these movements, and also result in widespread changes in the transcriptional profile promoting differentiation.
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Affiliation(s)
- Ann J Feeney
- Department of Immunology and Microbial Science, IMM22, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 920137, USA.
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Carabana J, Watanabe A, Hao B, Krangel MS. A barrier-type insulator forms a boundary between active and inactive chromatin at the murine TCRβ locus. THE JOURNAL OF IMMUNOLOGY 2011; 186:3556-62. [PMID: 21317385 DOI: 10.4049/jimmunol.1003164] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In CD4(-)CD8(-) double-negative thymocytes, the murine Tcrb locus is composed of alternating blocks of active and inactive chromatin containing Tcrb gene segments and trypsinogen genes, respectively. Although chromatin structure is appreciated to be critical for regulated recombination and expression of Tcrb gene segments, the molecular mechanisms that maintain the integrity of these differentially regulated Tcrb locus chromatin domains are not understood. We localized a boundary between active and inactive chromatin by mapping chromatin modifications across the interval extending from Prss2 (the most 3' trypsinogen gene) to D(β)1. This boundary, located 6 kb upstream of D(β)1, is characterized by a transition from repressive (histone H3 lysine 9 dimethylation [H3K9me2]) to active (histone H3 acetylation [H3ac]) chromatin and is marked by a peak of histone H3 lysine 4 dimethylation (H3K4me2) that colocalizes with a retroviral long terminal repeat (LTR). Histone H3 lysine 4 dimethylation is retained and histone H3 lysine 9 dimethylation fails to spread past the LTR even on alleles lacking the Tcrb enhancer (E(β)) suggesting that these features may be determined by the local DNA sequence. Notably, we found that LTR-containing DNA functions as a barrier-type insulator that can protect a transgene from negative chromosomal position effects. We propose that, in vivo, the LTR blocks the spread of heterochromatin, and thereby helps to maintain the integrity of the E(β)-regulated chromatin domain. We also identified low-abundance, E(β)-dependent transcripts that initiate at the border of the LTR and an adjacent long interspersed element. We speculate that this transcription, which extends across D(β), J(β) and C(β) gene segments, may play an additional role promoting initial opening of the E(β)-regulated chromatin domain.
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Affiliation(s)
- Juan Carabana
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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Abstract
Vertebrate development requires the formation of multiple cell types from a single genetic blueprint, an extraordinary feat that is guided by the dynamic and finely tuned reprogramming of gene expression. The sophisticated orchestration of gene expression programs is driven primarily by changes in the patterns of covalent chromatin modifications. These epigenetic changes are directed by cis elements, positioned across the genome, which provide docking sites for transcription factors and associated chromatin modifiers. Epigenetic changes impact all aspects of gene regulation, governing association with the machinery that drives transcription, replication, repair and recombination, a regulatory relationship that is dramatically illustrated in developing lymphocytes. The program of somatic rearrangements that assemble antigen receptor genes in precursor B and T cells has proven to be a fertile system for elucidating relationships between the genetic and epigenetic components of gene regulation. This chapter describes our current understanding of the cross-talk between key genetic elements and epigenetic programs during recombination of the Tcrb locus in developing T cells, how each contributes to the regulation of chromatin accessibility at individual DNA targets for recombination, and potential mechanisms that coordinate their actions.
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Matheson LS, Corcoran AE. Local and global epigenetic regulation of V(D)J recombination. Curr Top Microbiol Immunol 2011; 356:65-89. [PMID: 21695632 DOI: 10.1007/82_2011_137] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Despite using the same Rag recombinase machinery expressed in both lymphocyte lineages, V(D)J recombination of immunoglobulins only occurs in B cells and T cell receptor recombination is confined to T cells. This vital segregation of recombination targets is governed by the coordinated efforts of several epigenetic mechanisms that control both the general chromatin accessibility of these loci to the Rag recombinase, and the movement and synapsis of distal gene segments in these enormous multigene AgR loci, in a lineage and developmental stage-specific manner. These mechanisms operate both locally at individual gene segments and AgR domains, and globally over large distances in the nucleus. Here we will discuss the roles of several epigenetic components that regulate V(D)J recombination of the immunoglobulin heavy chain locus in B cells, both in the context of the locus itself, and of its 3D nuclear organization, focusing in particular on non-coding RNA transcription. We will also speculate about how several newly described epigenetic mechanisms might impact on AgR regulation.
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Affiliation(s)
- Louise S Matheson
- Laboratory of Chromatin and Gene Expression, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK
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50
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Subrahmanyam R, Sen R. Epigenetic features that regulate IgH locus recombination and expression. Curr Top Microbiol Immunol 2011; 356:39-63. [PMID: 21779986 DOI: 10.1007/82_2011_153] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Precisely regulated rearrangements that yield imprecise recombination junctions are hallmarks of antigen receptor gene assembly. At the immunoglobulin heavy chain (IgH) gene locus this is initiated by rearrangement of a D (H) gene segment to a J (H) gene segment to generate DJ(H) junctions, followed by rearrangement of a V (H) gene segment to the DJ(H) junction to generate fully recombined VDJ alleles. In this review we discuss the regulatory features of each step of IgH gene assembly and the role of epigenetic mechanisms in achieving regulatory precision.
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Affiliation(s)
- Ramesh Subrahmanyam
- National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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