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Dauba A, Khamlichi AA. Long-Range Control of Class Switch Recombination by Transcriptional Regulatory Elements. Front Immunol 2021; 12:738216. [PMID: 34594340 PMCID: PMC8477019 DOI: 10.3389/fimmu.2021.738216] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 08/17/2021] [Indexed: 01/18/2023] Open
Abstract
Immunoglobulin class switch recombination (CSR) plays a crucial role in adaptive immune responses through a change of the effector functions of antibodies and is triggered by T-cell-dependent as well as T-cell-independent antigens. Signals generated following encounter with each type of antigen direct CSR to different isotypes. At the genomic level, CSR occurs between highly repetitive switch sequences located upstream of the constant gene exons of the immunoglobulin heavy chain locus. Transcription of switch sequences is mandatory for CSR and is induced in a stimulation-dependent manner. Switch transcription takes place within dynamic chromatin domains and is regulated by long-range regulatory elements which promote alignment of partner switch regions in CSR centers. Here, we review recent work and models that account for the function of long-range transcriptional regulatory elements and the chromatin-based mechanisms involved in the control of CSR.
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Affiliation(s)
- Audrey Dauba
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, Toulouse, France
| | - Ahmed Amine Khamlichi
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, Toulouse, France
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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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V(D)J recombination process and the Pre-B to immature B-cells transition are altered in Fanca -/- mice. Sci Rep 2016; 6:36906. [PMID: 27883081 PMCID: PMC5121645 DOI: 10.1038/srep36906] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 10/20/2016] [Indexed: 12/13/2022] Open
Abstract
B-lymphocytes in the bone marrow (BM) must generate a functional B-cell receptor and overcome the negative selection induced by reactivity with autoantigens. Two rounds of DNA recombination are required for the production of functional immunoglobulin heavy (Ig-HCs) and light (LCs) chains necessary for the continuation of B-lymphocyte development in the BM. Both rounds depend on the joint action of recombination activating gene-1 (RAG-1) and RAG-2 endonucleases with the DNA non-homologous end-joining pathway. Loss of the FANC gene leads to the chromosome breakage and cancer predisposition syndrome Fanconi anemia. Because the FANC proteins are involved in certain aspects of the recombination process, we sought to determine the impact of the FANC pathway on the Ig diversification process using Fanca−/− mice. In this work we demonstrated that Fanca−/− animals have a mild B-cell differentiation defect characterized by a specific alteration of the IgM− to IgM+ transition of the B220low B-cell population. Pre-B cells from Fanca−/− mice show evidence of impaired kLC rearrangement at the level of the Vk-Jk junction. Furthermore, Fanca−/− mice showed a skewed Vκ gene usage during formation of the LCs Vk-Jk junctions. Therefore, the Fanca protein appears as a yet unidentified factor involved in the primary diversification of Ig.
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Belyea BC, Xu F, Pentz ES, Medrano S, Li M, Hu Y, Turner S, Legallo R, Jones CA, Tario JD, Liang P, Gross KW, Sequeira-Lopez MLS, Gomez RA. Identification of renin progenitors in the mouse bone marrow that give rise to B-cell leukaemia. Nat Commun 2015; 5:3273. [PMID: 24549417 PMCID: PMC3929784 DOI: 10.1038/ncomms4273] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Accepted: 01/16/2014] [Indexed: 01/28/2023] Open
Abstract
The cell of origin and triggering events for leukaemia are mostly unknown. Here we show that the bone marrow contains a progenitor that expresses renin throughout development and possesses a B-lymphocyte pedigree. This cell requires RBP-J to differentiate. Deletion of RBP-J in these renin-expressing progenitors enriches the precursor B-cell gene programme and constrains lymphocyte differentiation, facilitated by H3K4me3 activating marks in genes that control the pre-B stage. Mutant cells undergo neoplastic transformation, and mice develop a highly penetrant B-cell leukaemia with multi-organ infiltration and early death. These renin-expressing cells appear uniquely vulnerable as other conditional models of RBP-J deletion do not result in leukaemia. The discovery of these unique renin progenitors in the bone marrow and the model of leukaemia described herein may enhance our understanding of normal and neoplastic haematopoiesis.
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Affiliation(s)
- Brian C Belyea
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
| | - Fang Xu
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
| | - Ellen S Pentz
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
| | - Silvia Medrano
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
| | - Minghong Li
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
| | - Yan Hu
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
| | - Stephen Turner
- Department of Bioinformatics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
| | - Robin Legallo
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
| | - Craig A Jones
- Roswell Park Cancer Institute, Buffalo, New York 14263, USA
| | - Joseph D Tario
- Roswell Park Cancer Institute, Buffalo, New York 14263, USA
| | - Ping Liang
- Department of Biological Sciences, Brock University, St Catharines, Ontario, L2S 3A1, Canada
| | | | | | - R Ariel Gomez
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
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Günal-Sadık G, Paszkowski-Rogacz M, Singaravelu K, Beyer A, Buchholz F, Jessberger R. Stage-specific binding profiles of cohesin in resting and activated B lymphocytes suggest a role for cohesin in immunoglobulin class switching and maturation. PLoS One 2014; 9:e111748. [PMID: 25375358 PMCID: PMC4222939 DOI: 10.1371/journal.pone.0111748] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 09/30/2014] [Indexed: 11/19/2022] Open
Abstract
The immunoglobulin heavy chain locus (Igh) features higher-order chromosomal interactions to facilitate stage-specific assembly of the Ig molecule. Cohesin, a ring-like protein complex required for sister chromatid cohesion, shapes chromosome architecture and chromatin interactions important for transcriptional regulation and often acts together with CTCF. Cohesin is likely involved in B cell activation and Ig class switch recombination. Hence, binding profiles of cohesin in resting mature murine splenic B lymphocytes and at two stages after cell activation were elucidated by chromatin immunoprecipitation and deep sequencing. Comparative genomic analysis revealed cohesin extensively changes its binding to transcriptional control elements after 48 h of stimulation with LPS/IL-4. Cohesin was clearly underrepresented at switch regions regardless of their activation status, suggesting that switch regions need to be cohesin-poor. Specific binding changes of cohesin at B-cell specific gene loci Pax5 and Blimp-1 indicate new cohesin-dependent regulatory pathways. Together with conserved cohesin/CTCF sites at the Igh 3'RR, a prominent cohesin/CTCF binding site was revealed near the 3' end of Cα where PolII localizes to 3' enhancers. Our study shows that cohesin likely regulates B cell activation and maturation, including Ig class switching.
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Affiliation(s)
- Gamze Günal-Sadık
- Institute of Physiological Chemistry, Faculty of Medicine Carl Gustav Carus, Dresden University of Technology, Dresden, Germany
| | - Maciej Paszkowski-Rogacz
- Department of Medical Systems Biology, University Hospital and Medical Faculty Carl Gustav Carus, Dresden University of Technology, Dresden, Germany
| | - Kalaimathy Singaravelu
- Cellular Networks and Systems Biology, Biotechnology Center, Dresden University of Technology, Dresden, Germany
| | - Andreas Beyer
- Cellular Networks and Systems Biology, Biotechnology Center, Dresden University of Technology, Dresden, Germany
- CECAD, Universität zu Köln, Köln, Germany
| | - Frank Buchholz
- Department of Medical Systems Biology, University Hospital and Medical Faculty Carl Gustav Carus, Dresden University of Technology, Dresden, Germany
| | - Rolf Jessberger
- Institute of Physiological Chemistry, Faculty of Medicine Carl Gustav Carus, Dresden University of Technology, Dresden, Germany
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Precise and in situ genetic humanization of 6 Mb of mouse immunoglobulin genes. Proc Natl Acad Sci U S A 2014; 111:5147-52. [PMID: 24706858 DOI: 10.1073/pnas.1323896111] [Citation(s) in RCA: 284] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Genetic humanization, which involves replacing mouse genes with their human counterparts, can create powerful animal models for the study of human genes and diseases. One important example of genetic humanization involves mice humanized for their Ig genes, allowing for human antibody responses within a mouse background (HumAb mice) and also providing a valuable platform for the generation of fully human antibodies as therapeutics. However, existing HumAb mice do not have fully functional immune systems, perhaps because of the manner in which they were genetically humanized. Heretofore, most genetic humanizations have involved disruption of the endogenous mouse gene with simultaneous introduction of a human transgene at a new and random location (so-called KO-plus-transgenic humanization). More recent efforts have attempted to replace mouse genes with their human counterparts at the same genetic location (in situ humanization), but such efforts involved laborious procedures and were limited in size and precision. We describe a general and efficient method for very large, in situ, and precise genetic humanization using large compound bacterial artificial chromosome-based targeting vectors introduced into mouse ES cells. We applied this method to genetically humanize 3-Mb segments of both the mouse heavy and κ light chain Ig loci, by far the largest genetic humanizations ever described. This paper provides a detailed description of our genetic humanization approach, and the companion paper reports that the humoral immune systems of mice bearing these genetically humanized loci function as efficiently as those of WT mice.
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Venigalla RKC, McGuire VA, Clarke R, Patterson-Kane JC, Najafov A, Toth R, McCarthy PC, Simeons F, Stojanovski L, Arthur JSC. PDK1 regulates VDJ recombination, cell-cycle exit and survival during B-cell development. EMBO J 2013; 32:1008-22. [PMID: 23463102 PMCID: PMC3616287 DOI: 10.1038/emboj.2013.40] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2012] [Accepted: 01/30/2013] [Indexed: 01/25/2023] Open
Abstract
Phosphoinositide-dependent kinase-1 (PDK1) controls the activation of a subset of AGC kinases. Using a conditional knockout of PDK1 in haematopoietic cells, we demonstrate that PDK1 is essential for B cell development. B-cell progenitors lacking PDK1 arrested at the transition of pro-B to pre-B cells, due to a cell autonomous defect. Loss of PDK1 decreased the expression of the IgH chain in pro-B cells due to impaired recombination of the IgH distal variable segments, a process coordinated by the transcription factor Pax5. The expression of Pax5 in pre-B cells was decreased in PDK1 knockouts, which correlated with reduced expression of the Pax5 target genes IRF4, IRF8 and Aiolos. As a result, Ccnd3 is upregulated in PDK1 knockout pre-B cells and they have an impaired ability to undergo cell-cycle arrest, a necessary event for Ig light chain rearrangement. Instead, these cells underwent apoptosis that correlated with diminished expression of the pro-survival gene Bcl2A1. Reintroduction of both Pax5 and Bcl2A1 together into PDK1 knockout pro-B cells restored their ability to differentiate in vitro into mature B cells.
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Affiliation(s)
- Ram K C Venigalla
- MRC Protein Phosphorylation Unit, Sir James Black Centre, College of Life Sciences, University of Dundee, Dundee, UK.
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Perlot T, Penninger JM. Development and function of murine B cells lacking RANK. THE JOURNAL OF IMMUNOLOGY 2012; 188:1201-5. [PMID: 22219325 DOI: 10.4049/jimmunol.1102063] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
RANKL-RANK signaling regulates numerous physiologic processes such as bone remodeling, lymph node organogenesis, central thermoregulation, and formation of a lactating mammary gland in pregnancy. Recently, a receptor activator of NF-κB ligand (RANKL)-blocking Ab has been approved for human use in potentially millions of osteoporosis and cancer patients. However, germline deficiencies in RANKL or receptor activator of NF-κB (RANK) also lead to strong B cell defects in mice and human patients, suggesting that RANKL-RANK inhibition could interfere with B cell physiology and thereby trigger immunologic side-effects. To address this key question--that is, whether RANKL-RANK signaling affects B cell physiology directly or the observed defects are secondary because of the severe osteopetrosis--we generated B cell-specific RANK knockout mice. We show that B cells deficient for RANK undergo normal development and do not show any obvious defects in Ab secretion, class switch recombination, or somatic hypermutation. Our data indicate that ablation of the RANKL-RANK pathway has no direct adverse effect on B cell physiology.
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Affiliation(s)
- Thomas Perlot
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, 1030 Vienna, Austria
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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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