1
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Chang LH, Noordermeer D. Permeable TAD boundaries and their impact on genome-associated functions. Bioessays 2024; 46:e2400137. [PMID: 39093600 DOI: 10.1002/bies.202400137] [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: 06/05/2024] [Revised: 07/12/2024] [Accepted: 07/17/2024] [Indexed: 08/04/2024]
Abstract
TAD boundaries are genomic elements that separate biological processes in neighboring domains by blocking DNA loops that are formed through Cohesin-mediated loop extrusion. Most TAD boundaries consist of arrays of binding sites for the CTCF protein, whose interaction with the Cohesin complex blocks loop extrusion. TAD boundaries are not fully impermeable though and allow a limited amount of inter-TAD loop formation. Based on the reanalysis of Nano-C data, a multicontact Chromosome Conformation Capture assay, we propose a model whereby clustered CTCF binding sites promote the successive stalling of Cohesin and subsequent dissociation from the chromatin. A fraction of Cohesin nonetheless achieves boundary read-through. Due to a constant rate of Cohesin dissociation elsewhere in the genome, the maximum length of inter-TAD loops is restricted though. We speculate that the DNA-encoded organization of stalling sites regulates TAD boundary permeability and discuss implications for enhancer-promoter loop formation and other genomic processes.
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Affiliation(s)
- Li-Hsin Chang
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
- Blood and Transplant Research Unit in Precision Cellular Therapeutics, National Institute of Health Research, Oxford, UK
| | - Daan Noordermeer
- CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, Gif-sur-Yvette, France
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2
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Guérin TM, Barrington C, Pobegalov G, Molodtsov MI, Uhlmann F. An extrinsic motor directs chromatin loop formation by cohesin. EMBO J 2024:10.1038/s44318-024-00202-5. [PMID: 39160275 DOI: 10.1038/s44318-024-00202-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 07/30/2024] [Accepted: 07/31/2024] [Indexed: 08/21/2024] Open
Abstract
The ring-shaped cohesin complex topologically entraps two DNA molecules to establish sister chromatid cohesion. Cohesin also shapes the interphase chromatin landscape with wide-ranging implications for gene regulation, and cohesin is thought to achieve this by actively extruding DNA loops without topologically entrapping DNA. The 'loop extrusion' hypothesis finds motivation from in vitro observations-whether this process underlies in vivo chromatin loop formation remains untested. Here, using the budding yeast S. cerevisiae, we generate cohesin variants that have lost their ability to extrude DNA loops but retain their ability to topologically entrap DNA. Analysis of these variants suggests that in vivo chromatin loops form independently of loop extrusion. Instead, we find that transcription promotes loop formation, and acts as an extrinsic motor that expands these loops and defines their ultimate positions. Our results necessitate a re-evaluation of the loop extrusion hypothesis. We propose that cohesin, akin to sister chromatid cohesion establishment at replication forks, forms chromatin loops by DNA-DNA capture at places of transcription, thus unifying cohesin's two roles in chromosome segregation and interphase genome organisation.
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Affiliation(s)
- Thomas M Guérin
- Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK
- Université Paris Cité and Université Paris-Saclay, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, Fontenay-aux-Roses, France
| | - Christopher Barrington
- Bioinformatics & Biostatistics Science Technology Platform, The Francis Crick Institute, London, UK
| | - Georgii Pobegalov
- Mechanobiology and Biophysics Laboratory, The Francis Crick Institute, London, UK
- Department of Physics and Astronomy, University College London, London, UK
| | - Maxim I Molodtsov
- Mechanobiology and Biophysics Laboratory, The Francis Crick Institute, London, UK
- Department of Physics and Astronomy, University College London, London, UK
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK.
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3
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Zhang Y, Li X, Ba Z, Lou J, Gaertner KE, Zhu T, Lin X, Ye AY, Alt FW, Hu H. Molecular basis for differential Igk versus Igh V(D)J joining mechanisms. Nature 2024; 630:189-197. [PMID: 38811728 PMCID: PMC11153149 DOI: 10.1038/s41586-024-07477-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 04/26/2024] [Indexed: 05/31/2024]
Abstract
In developing B cells, V(D)J recombination assembles exons encoding IgH and Igκ variable regions from hundreds of gene segments clustered across Igh and Igk loci. V, D and J gene segments are flanked by conserved recombination signal sequences (RSSs) that target RAG endonuclease1. RAG orchestrates Igh V(D)J recombination upon capturing a JH-RSS within the JH-RSS-based recombination centre1-3 (RC). JH-RSS orientation programmes RAG to scan upstream D- and VH-containing chromatin that is presented in a linear manner by cohesin-mediated loop extrusion4-7. During Igh scanning, RAG robustly utilizes only D-RSSs or VH-RSSs in convergent (deletional) orientation with JH-RSSs4-7. However, for Vκ-to-Jκ joining, RAG utilizes Vκ-RSSs from deletional- and inversional-oriented clusters8, inconsistent with linear scanning2. Here we characterize the Vκ-to-Jκ joining mechanism. Igk undergoes robust primary and secondary rearrangements9,10, which confounds scanning assays. We therefore engineered cells to undergo only primary Vκ-to-Jκ rearrangements and found that RAG scanning from the primary Jκ-RC terminates just 8 kb upstream within the CTCF-site-based Sis element11. Whereas Sis and the Jκ-RC barely interacted with the Vκ locus, the CTCF-site-based Cer element12 4 kb upstream of Sis interacted with various loop extrusion impediments across the locus. Similar to VH locus inversion7, DJH inversion abrogated VH-to-DJH joining; yet Vκ locus or Jκ inversion allowed robust Vκ-to-Jκ joining. Together, these experiments implicated loop extrusion in bringing Vκ segments near Cer for short-range diffusion-mediated capture by RC-based RAG. To identify key mechanistic elements for diffusional V(D)J recombination in Igk versus Igh, we assayed Vκ-to-JH and D-to-Jκ rearrangements in hybrid Igh-Igk loci generated by targeted chromosomal translocations, and pinpointed remarkably strong Vκ and Jκ RSSs. Indeed, RSS replacements in hybrid or normal Igk and Igh loci confirmed the ability of Igk-RSSs to promote robust diffusional joining compared with Igh-RSSs. We propose that Igk evolved strong RSSs to mediate diffusional Vκ-to-Jκ joining, whereas Igh evolved weaker RSSs requisite for modulating VH joining by RAG-scanning impediments.
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Affiliation(s)
- Yiwen Zhang
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Xiang Li
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Zhaoqing Ba
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- National Institute of Biological Sciences, Beijing, China
| | - Jiangman Lou
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Copenhagen University, Copenhagen, Denmark
| | - K Elyse Gaertner
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Georgetown University, Washington, DC, USA
| | - Tammie Zhu
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Xin Lin
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Adam Yongxin Ye
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Frederick W Alt
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.
- Department of Genetics, Harvard Medical School, Boston, MA, USA.
| | - Hongli Hu
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.
- Department of Genetics, Harvard Medical School, Boston, MA, USA.
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4
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Ma F, Cao Y, Du H, Braikia FZ, Zong L, Ollikainen N, Bayer M, Qiu X, Park B, Roy R, Nandi S, Sarantopoulou D, Ziman A, Bianchi AH, Beerman I, Zhao K, Grosschedl R, Sen R. Three-dimensional chromatin reorganization regulates B cell development during ageing. Nat Cell Biol 2024; 26:991-1002. [PMID: 38866970 PMCID: PMC11178499 DOI: 10.1038/s41556-024-01424-9] [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: 11/01/2022] [Accepted: 04/16/2024] [Indexed: 06/14/2024]
Abstract
The contribution of three-dimensional genome organization to physiological ageing is not well known. Here we show that large-scale chromatin reorganization distinguishes young and old bone marrow progenitor (pro-) B cells. These changes result in increased interactions at the compartment level and reduced interactions within topologically associated domains (TADs). The gene encoding Ebf1, a key B cell regulator, switches from compartment A to B with age. Genetically reducing Ebf1 recapitulates some features of old pro-B cells. TADs that are most reduced with age contain genes important for B cell development, including the immunoglobulin heavy chain (Igh) locus. Weaker intra-TAD interactions at Igh correlate with altered variable (V), diversity (D) and joining (J) gene recombination. Our observations implicate three-dimensional chromatin reorganization as a major driver of pro-B cell phenotypes that impair B lymphopoiesis with age.
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Affiliation(s)
- Fei Ma
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD, USA
| | - Yaqiang Cao
- Laboratory of Epigenome Biology, Systems Biology Center, National Heart, Lung and Blood Institute, Bethesda, MD, USA
| | - Hansen Du
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD, USA
| | - Fatima Zohra Braikia
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD, USA
| | - Le Zong
- Epigenetics and Stem Cell Init, Translational Gerontology Branch, National Institute on Aging, Baltimore, MD, USA
| | - Noah Ollikainen
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD, USA
| | - Marc Bayer
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Xiang Qiu
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD, USA
| | - Bongsoo Park
- Epigenetics and Stem Cell Init, Translational Gerontology Branch, National Institute on Aging, Baltimore, MD, USA
| | - Roshni Roy
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD, USA
| | - Satabdi Nandi
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD, USA
| | - Dimitra Sarantopoulou
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD, USA
| | | | - Aisha Haley Bianchi
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD, USA
| | - Isabel Beerman
- Epigenetics and Stem Cell Init, Translational Gerontology Branch, National Institute on Aging, Baltimore, MD, USA
| | - Keji Zhao
- Laboratory of Epigenome Biology, Systems Biology Center, National Heart, Lung and Blood Institute, Bethesda, MD, USA
| | - Rudolf Grosschedl
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Ranjan Sen
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, Baltimore, MD, USA.
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5
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Wang J, Sadeghi CA, Frock RL. DNA-PKcs suppresses illegitimate chromosome rearrangements. Nucleic Acids Res 2024; 52:5048-5066. [PMID: 38412274 PMCID: PMC11109964 DOI: 10.1093/nar/gkae140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 02/09/2024] [Accepted: 02/14/2024] [Indexed: 02/29/2024] Open
Abstract
Two DNA repair pathways, non-homologous end joining (NHEJ) and alternative end joining (A-EJ), are involved in V(D)J recombination and chromosome translocation. Previous studies reported distinct repair mechanisms for chromosome translocation, with NHEJ involved in humans and A-EJ in mice predominantly. NHEJ depends on DNA-PKcs, a critical partner in synapsis formation and downstream component activation. While DNA-PKcs inhibition promotes chromosome translocations harboring microhomologies in mice, its synonymous effect in humans is not known. We find partial DNA-PKcs inhibition in human cells leads to increased translocations and the continued involvement of a dampened NHEJ. In contrast, complete DNA-PKcs inhibition substantially increased microhomology-mediated end joining (MMEJ), thus bridging the two different translocation mechanisms between human and mice. Similar to a previous study on Ku70 deletion, DNA-PKcs deletion in G1/G0-phase mouse progenitor B cell lines, significantly impairs V(D)J recombination and generated higher rates of translocations as a consequence of dysregulated coding and signal end joining. Genetic DNA-PKcs inhibition suppresses NHEJ entirely, with repair phenotypically resembling Ku70-deficient A-EJ. In contrast, we find DNA-PKcs necessary in generating the near-exclusive MMEJ associated with Lig4 deficiency. Our study underscores DNA-PKcs in suppressing illegitimate chromosome rearrangement while also contributing to MMEJ in both species.
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Affiliation(s)
- Jinglong Wang
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Cheyenne A Sadeghi
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Richard L Frock
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
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6
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Leeman-Neill RJ, Bhagat G, Basu U. AID in non-Hodgkin B-cell lymphomas: The consequences of on- and off-target activity. Adv Immunol 2024; 161:127-164. [PMID: 38763700 DOI: 10.1016/bs.ai.2024.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2024]
Abstract
Activation induced cytidine deaminase (AID) is a key element of the adaptive immune system, required for immunoglobulin isotype switching and affinity maturation of B-cells as they undergo the germinal center (GC) reaction in peripheral lymphoid tissue. The inherent DNA damaging activity of this enzyme can also have off-target effects in B-cells, producing lymphomagenic chromosomal translocations that are characteristic features of various classes of non-Hodgkin B-cell lymphoma (B-NHL), and generating oncogenic mutations, so-called aberrant somatic hypermutation (aSHM). Additionally, AID has been found to affect gene expression through demethylation as well as altered interactions between gene regulatory elements. These changes have been most thoroughly studied in B-NHL arising from GC B-cells. Here, we describe the most common classes of GC-derived B-NHL and explore the consequences of on- and off-target AID activity in B and plasma cell neoplasms. The relationships between AID expression, including effects of infection and other exposures/agents, mutagenic activity and lymphoma biology are also discussed.
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Affiliation(s)
- Rebecca J Leeman-Neill
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States; Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States.
| | - Govind Bhagat
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States
| | - Uttiya Basu
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States
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7
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Allyn BM, Hayer KE, Oyeniran C, Nganga V, Lee K, Mishra B, Sacan A, Oltz EM, Bassing CH. Locus folding mechanisms determine modes of antigen receptor gene assembly. J Exp Med 2024; 221:e20230985. [PMID: 38189780 PMCID: PMC10772921 DOI: 10.1084/jem.20230985] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 10/12/2023] [Accepted: 12/15/2023] [Indexed: 01/09/2024] Open
Abstract
The dynamic folding of genomes regulates numerous biological processes, including antigen receptor (AgR) gene assembly. We show that, unlike other AgR loci, homotypic chromatin interactions and bidirectional chromosome looping both contribute to structuring Tcrb for efficient long-range V(D)J recombination. Inactivation of the CTCF binding element (CBE) or promoter at the most 5'Vβ segment (Trbv1) impaired loop extrusion originating locally and extending to DβJβ CBEs at the opposite end of Tcrb. Promoter or CBE mutation nearly eliminated Trbv1 contacts and decreased RAG endonuclease-mediated Trbv1 recombination. Importantly, Trbv1 rearrangement can proceed independent of substrate orientation, ruling out scanning by DβJβ-bound RAG as the sole mechanism of Vβ recombination, distinguishing it from Igh. Our data indicate that CBE-dependent generation of loops cooperates with promoter-mediated activation of chromatin to juxtapose Vβ and DβJβ segments for recombination through diffusion-based synapsis. Thus, the mechanisms that fold a genomic region can influence molecular processes occurring in that space, which may include recombination, repair, and transcriptional programming.
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Affiliation(s)
- Brittney M. Allyn
- Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Katharina E. Hayer
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Biomedical Engineering Doctoral Degree Program, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA
- Department of Biomedical and Health Informatics, Children’s Hospital of Philadelphia, Perelman School of Medicine, Philadelphia, PA, USA
| | - Clement Oyeniran
- Department of Microbial Infection and Immunity, Ohio State College of Medicine, Ohio State University, Columbus, OH, USA
| | - Vincent Nganga
- Department of Microbial Infection and Immunity, Ohio State College of Medicine, Ohio State University, Columbus, OH, USA
| | - Kyutae Lee
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Bikash Mishra
- Department of Microbial Infection and Immunity, Ohio State College of Medicine, Ohio State University, Columbus, OH, USA
| | - Ahmet Sacan
- Biomedical Engineering Doctoral Degree Program, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA
| | - Eugene M. Oltz
- Department of Microbial Infection and Immunity, Ohio State College of Medicine, Ohio State University, Columbus, OH, USA
| | - Craig H. Bassing
- Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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8
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Li L, Zhang D, Cao X. EBF1, PAX5, and MYC: regulation on B cell development and association with hematologic neoplasms. Front Immunol 2024; 15:1320689. [PMID: 38318177 PMCID: PMC10839018 DOI: 10.3389/fimmu.2024.1320689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 01/08/2024] [Indexed: 02/07/2024] Open
Abstract
During lymphocyte development, a diverse repertoire of lymphocyte antigen receptors is produced to battle against pathogens, which is the basis of adaptive immunity. The diversity of the lymphocyte antigen receptors arises primarily from recombination-activated gene (RAG) protein-mediated V(D)J rearrangement in early lymphocytes. Furthermore, transcription factors (TFs), such as early B cell factor 1 (EBF1), paired box gene 5 (PAX5), and proto-oncogene myelocytomatosis oncogene (MYC), play critical roles in regulating recombination and maintaining normal B cell development. Therefore, the aberrant expression of these TFs may lead to hematologic neoplasms.
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Affiliation(s)
- Li Li
- Immune Mechanism and Therapy of Major Diseases of Luzhou Key Laboratory, School of Basic Medical Sciences, Southwest Medical University, Luzhou, China
| | - Daiquan Zhang
- Department of Traditional Chinese Medicine, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Xinmei Cao
- Immune Mechanism and Therapy of Major Diseases of Luzhou Key Laboratory, School of Basic Medical Sciences, Southwest Medical University, Luzhou, China
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9
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Zhang R, Wang D, Ruan GX, Wang R, Li Y, Chen W, Huang H, Wang J, Meng L, Zhu Z, Lei D, Xu S, Ou X. Spliceosome component PHD finger 5A is essential for early B lymphopoiesis. Development 2024; 151:dev202247. [PMID: 38095286 DOI: 10.1242/dev.202247] [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: 08/08/2023] [Accepted: 12/08/2023] [Indexed: 01/12/2024]
Abstract
The spliceosome, a multi-megadalton ribonucleoprotein complex, is essential for pre-mRNA splicing in the nucleus and ensuring genomic stability. Its precise and dynamic assembly is pivotal for its function. Spliceosome malfunctions can lead to developmental abnormalities and potentially contribute to tumorigenesis. The specific role of the spliceosome in B cell development is poorly understood. Here, we reveal that the spliceosomal U2 snRNP component PHD finger protein 5A (Phf5a) is vital for early B cell development. Loss of Phf5a results in pronounced defects in B cell development, causing an arrest at the transition from pre-pro-B to early pro-B cell stage in the bone marrow of mutant mice. Phf5a-deficient B cells exhibit impaired immunoglobulin heavy (IgH) chain expression due to defective V-to-DJ gene rearrangement. Mechanistically, our findings suggest that Phf5a facilitates IgH gene rearrangement by regulating the activity of recombination-activating gene endonuclease and influencing chromatin interactions at the Igh locus.
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Affiliation(s)
- Rui Zhang
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Daoqin Wang
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Gui-Xin Ruan
- Medical School, Taizhou University, Taizhou 318000, China
| | - Ruisi Wang
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yuxing Li
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wenjing Chen
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Hengjun Huang
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jing Wang
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Limin Meng
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zhijian Zhu
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Dengfeng Lei
- Department of Ophthalmology, Southern University of Science and Technology Hospital, Shenzhen 518055, China
| | - Shengli Xu
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, Immunos, Singapore 138648, Republic of Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 2 Medical Drive MD9, Singapore 117593, Republic of Singapore
| | - Xijun Ou
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
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10
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Mandal M, Maienschein-Cline M, Hu Y, Mohsin A, Veselits ML, Wright NE, Okoreeh MK, Yoon YM, Veselits J, Georgopoulos K, Clark MR. BRWD1 orchestrates small pre-B cell chromatin topology by converting static to dynamic cohesin. Nat Immunol 2024; 25:129-141. [PMID: 37985858 DOI: 10.1038/s41590-023-01666-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 09/29/2023] [Indexed: 11/22/2023]
Abstract
Lymphocyte development consists of sequential and mutually exclusive cell states of proliferative selection and antigen receptor gene recombination. Transitions between each state require large, coordinated changes in epigenetic landscapes and transcriptional programs. How this occurs remains unclear. Here we demonstrate that in small pre-B cells, the lineage and stage-specific epigenetic reader bromodomain and WD repeat-containing protein 1 (BRWD1) reorders three-dimensional chromatin topology to affect the transition between proliferative and gene recombination molecular programs. BRWD1 regulated the switch between poised and active enhancers interacting with promoters, and coordinated this switch with Igk locus contraction. BRWD1 did so by converting chromatin-bound static to dynamic cohesin competent to mediate long-range looping. ATP-depletion revealed cohesin conversion to be the main energetic mechanism dictating dynamic chromatin looping. Our findings provide a new mechanism of cohesin regulation and reveal how cohesin function can be dictated by lineage contextual mechanisms to facilitate specific cell fate transitions.
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Affiliation(s)
- Malay Mandal
- Department of Medicine, Section of Rheumatology and Gwen Knapp Center for Lupus and Immunology Research, University of Chicago, Chicago, IL, USA.
| | | | - Yeguang Hu
- Cutaneous Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Azam Mohsin
- Program in Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Margaret L Veselits
- Department of Medicine, Section of Rheumatology and Gwen Knapp Center for Lupus and Immunology Research, University of Chicago, Chicago, IL, USA
| | - Nathaniel E Wright
- Department of Medicine, Section of Rheumatology and Gwen Knapp Center for Lupus and Immunology Research, University of Chicago, Chicago, IL, USA
| | - Michael K Okoreeh
- Department of Medicine, Section of Rheumatology and Gwen Knapp Center for Lupus and Immunology Research, University of Chicago, Chicago, IL, USA
| | - Young Me Yoon
- Department of Medicine, Section of Rheumatology and Gwen Knapp Center for Lupus and Immunology Research, University of Chicago, Chicago, IL, USA
| | - Jacob Veselits
- Department of Medicine, Section of Rheumatology and Gwen Knapp Center for Lupus and Immunology Research, University of Chicago, Chicago, IL, USA
| | - Katia Georgopoulos
- Cutaneous Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Marcus R Clark
- Department of Medicine, Section of Rheumatology and Gwen Knapp Center for Lupus and Immunology Research, University of Chicago, Chicago, IL, USA.
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11
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Barajas-Mora EM, Feeney AJ. Enhancers within the Ig V Gene Region Orchestrate Chromatin Topology and Regulate V Gene Rearrangement Frequency to Shape the B Cell Receptor Repertoire Specificities. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 211:1613-1622. [PMID: 37983521 PMCID: PMC10662671 DOI: 10.4049/jimmunol.2300261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 06/01/2023] [Indexed: 11/22/2023]
Abstract
Effective Ab-mediated responses depend on a highly diverse Ab repertoire with the ability to bind a wide range of epitopes in disease-causing agents. The generation of this repertoire depends on the somatic recombination of the variable (V), diversity (D), and joining (J) genes in the Ig loci of developing B cells. It has been known for some time that individual V, D, and J gene segments rearrange at different frequencies, but the mechanisms behind this unequal V gene usage have not been well understood. However, recent work has revealed that newly described enhancers scattered throughout the V gene-containing portion of the Ig loci regulate the V gene recombination frequency in a regional manner. Deletion of three of these enhancers revealed that these elements exert many layers of control during V(D)J recombination, including long-range chromatin interactions, epigenetic milieu, chromatin accessibility, and compartmentalization.
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Affiliation(s)
- E. Mauricio Barajas-Mora
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA, USA, Current address: Poseida Therapeutics, Inc. San Diego, CA
| | - Ann J. Feeney
- Scripps Research, Department of Immunology and Microbiology, La Jolla, CA 92014
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12
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Gao Z, Smith AL, Scott JF, Bevington S, Boyes J. Temporal analyses reveal a pivotal role for sense and antisense enhancer RNAs in coordinate immunoglobulin lambda locus activation. Nucleic Acids Res 2023; 51:10344-10363. [PMID: 37702072 PMCID: PMC10602925 DOI: 10.1093/nar/gkad741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 08/24/2023] [Accepted: 08/30/2023] [Indexed: 09/14/2023] Open
Abstract
Transcription enhancers are essential activators of V(D)J recombination that orchestrate non-coding transcription through complementary, unrearranged gene segments. How transcription is coordinately increased at spatially distinct promoters, however, remains poorly understood. Using the murine immunoglobulin lambda (Igλ) locus as model, we find that three enhancer-like elements in the 3' Igλ domain, Eλ3-1, HSCλ1 and HSE-1, show strikingly similar transcription factor binding dynamics and close spatial proximity, suggesting that they form an active enhancer hub. Temporal analyses show coordinate recruitment of complementary V and J gene segments to this hub, with comparable transcription factor binding dynamics to that at enhancers. We find further that E2A, p300, Mediator and Integrator bind to enhancers as early events, whereas YY1 recruitment and eRNA synthesis occur later, corresponding to transcription activation. Remarkably, the interplay between sense and antisense enhancer RNA is central to both active enhancer hub formation and coordinate Igλ transcription: Antisense Eλ3-1 eRNA represses Igλ activation whereas temporal analyses demonstrate that accumulating levels of sense eRNA boost YY1 recruitment to stabilise enhancer hub/promoter interactions and lead to coordinate transcription activation. These studies therefore demonstrate for the first time a critical role for threshold levels of sense versus antisense eRNA in locus activation.
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Affiliation(s)
- Zeqian Gao
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Alastair L Smith
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - James N F Scott
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Sarah L Bevington
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Joan Boyes
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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13
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Dai R, Zhu Y, Li Z, Qin L, Liu N, Liao S, Hao B. Three-way contact analysis characterizes the higher order organization of the Tcra locus. Nucleic Acids Res 2023; 51:8987-9000. [PMID: 37534534 PMCID: PMC10516640 DOI: 10.1093/nar/gkad641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 07/07/2023] [Accepted: 07/20/2023] [Indexed: 08/04/2023] Open
Abstract
The generation of highly diverse antigen receptors in T and B lymphocytes relies on V(D)J recombination. The enhancer Eα has been implicated in regulating the accessibility of Vα and Jα genes through long-range interactions during rearrangements of the T-cell antigen receptor gene Tcra. However, direct evidence for Eα physically mediating the interaction of Vα and Jα genes is still lacking. In this study, we utilized the 3C-HTGTS assay, a chromatin interaction technique based on 3C, to analyze the higher order chromatin structure of the Tcra locus. Our analysis revealed the presence of sufficient information in the 3C-HTGTS data to detect multiway contacts. Three-way contact analysis of the Tcra locus demonstrated the co-occurrence of the proximal Jα genes, Vα genes and Eα in CD4+CD8+ double-positive thymocytes. Notably, the INT2-TEAp loop emerged as a prominent structure likely to be responsible for bringing the proximal Jα genes and the Vα genes into proximity. Moreover, the enhancer Eα utilizes this loop to establish physical proximity with the proximal Vα gene region. This study provides insights into the higher order chromatin structure of the Tcra locus, shedding light on the spatial organization of chromatin and its impact on V(D)J recombination.
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Affiliation(s)
- Ranran Dai
- Cancer Research Institute, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong Province 510515, China
| | - Yongchang Zhu
- Department of Immunology, School of Basic Medical, Zhengzhou University, Zhengzhou 450001, China
- Medical Genetic Institute of Henan Province, Henan Key Laboratory of Genetic Diseases and Functional Genomics, National Health Commission Key Laboratory of Birth Defects Prevention, Henan Provincial People’s Hospital, People’s Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan Province 450003, China
| | - Zhaoqiang Li
- Cancer Research Institute, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong Province 510515, China
| | - Litao Qin
- Medical Genetic Institute of Henan Province, Henan Key Laboratory of Genetic Diseases and Functional Genomics, National Health Commission Key Laboratory of Birth Defects Prevention, Henan Provincial People’s Hospital, People’s Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan Province 450003, China
| | - Nan Liu
- Division of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province 510515, China
| | - Shixiu Liao
- Medical Genetic Institute of Henan Province, Henan Key Laboratory of Genetic Diseases and Functional Genomics, National Health Commission Key Laboratory of Birth Defects Prevention, Henan Provincial People’s Hospital, People’s Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan Province 450003, China
| | - Bingtao Hao
- Cancer Research Institute, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong Province 510515, China
- Department of Immunology, School of Basic Medical, Zhengzhou University, Zhengzhou 450001, China
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14
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Chang LH, Ghosh S, Papale A, Luppino JM, Miranda M, Piras V, Degrouard J, Edouard J, Poncelet M, Lecouvreur N, Bloyer S, Leforestier A, Joyce EF, Holcman D, Noordermeer D. Multi-feature clustering of CTCF binding creates robustness for loop extrusion blocking and Topologically Associating Domain boundaries. Nat Commun 2023; 14:5615. [PMID: 37699887 PMCID: PMC10497529 DOI: 10.1038/s41467-023-41265-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 08/28/2023] [Indexed: 09/14/2023] Open
Abstract
Topologically Associating Domains (TADs) separate vertebrate genomes into insulated regulatory neighborhoods that focus genome-associated processes. TADs are formed by Cohesin-mediated loop extrusion, with many TAD boundaries consisting of clustered binding sites of the CTCF insulator protein. Here we determine how this clustering of CTCF binding contributes to the blocking of loop extrusion and the insulation between TADs. We identify enrichment of three features of CTCF binding at strong TAD boundaries, consisting of strongly bound and closely spaced CTCF binding peaks, with a further enrichment of DNA-binding motifs within these peaks. Using multi-contact Nano-C analysis in cells with normal and perturbed CTCF binding, we establish that individual CTCF binding sites contribute to the blocking of loop extrusion, but in an incomplete manner. When clustered, individual CTCF binding sites thus create a stepwise insulation between neighboring TADs. Based on these results, we propose a model whereby multiple instances of temporal loop extrusion blocking create strong insulation between TADs.
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Affiliation(s)
- Li-Hsin Chang
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, and National Institute of Health Research, Blood and Transplant Research Unit in Precision Cellular Therapeutics, OX3 9DS, Oxford, UK
| | - Sourav Ghosh
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
- Department of Pathology and Laboratory Medicine, Western University, N6A3K7, London, ON, Canada
| | - Andrea Papale
- École Normale Supérieure, IBENS, Université PSL, 75005, Paris, France
| | - Jennifer M Luppino
- Department of Genetics, Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Mélanie Miranda
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Vincent Piras
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Jéril Degrouard
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides (LPS), 91405, Orsay, France
| | - Joanne Edouard
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Mallory Poncelet
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Nathan Lecouvreur
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Sébastien Bloyer
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Amélie Leforestier
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides (LPS), 91405, Orsay, France
| | - Eric F Joyce
- Department of Genetics, Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David Holcman
- École Normale Supérieure, IBENS, Université PSL, 75005, Paris, France
- Churchill College, University of Cambridge, CB3 0DS, Cambridge, UK
| | - Daan Noordermeer
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
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15
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Abstract
Many cellular processes require large-scale rearrangements of chromatin structure. Structural maintenance of chromosomes (SMC) protein complexes are molecular machines that can provide structure to chromatin. These complexes can connect DNA elements in cis, walk along DNA, build and processively enlarge DNA loops and connect DNA molecules in trans to hold together the sister chromatids. These DNA-shaping abilities place SMC complexes at the heart of many DNA-based processes, including chromosome segregation in mitosis, transcription control and DNA replication, repair and recombination. In this Review, we discuss the latest insights into how SMC complexes such as cohesin, condensin and the SMC5-SMC6 complex shape DNA to direct these fundamental chromosomal processes. We also consider how SMC complexes, by building chromatin loops, can counteract the natural tendency of alike chromatin regions to cluster. SMC complexes thus control nuclear organization by participating in a molecular tug of war that determines the architecture of our genome.
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Affiliation(s)
- Claire Hoencamp
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Benjamin D Rowland
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
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16
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Wright NE, Mandal M, Clark MR. Molecular mechanisms insulating proliferation from genotoxic stress in B lymphocytes. Trends Immunol 2023; 44:668-677. [PMID: 37573227 PMCID: PMC10530527 DOI: 10.1016/j.it.2023.06.010] [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: 05/18/2023] [Revised: 06/25/2023] [Accepted: 06/30/2023] [Indexed: 08/14/2023]
Abstract
In mammals, B cells strictly segregate proliferation from somatic mutation as they develop within the bone marrow and then mature through germinal centers (GCs) in the periphery. Failure to do so risks autoimmunity and neoplastic transformation. Recent work has described how B cell progenitors transition between proliferation and mutation via cytokine signaling pathways, epigenetic chromatin regulation, and remodeling of 3D chromatin conformation. We propose a three-zone model of the GC that describes how proliferation and mutation are regulated. Using this model, we consider how recent mechanistic discoveries in B cell progenitors inform models of GC B cell function and reveal fundamental mechanisms underpinning humoral immunity, autoimmunity, and lymphomagenesis.
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Affiliation(s)
- Nathaniel E Wright
- Department of Medicine, Section of Rheumatology, and Gwen Knapp Center for Lupus and Immunology Research, University of Chicago, Chicago, IL, USA
| | - Malay Mandal
- Department of Medicine, Section of Rheumatology, and Gwen Knapp Center for Lupus and Immunology Research, University of Chicago, Chicago, IL, USA
| | - Marcus R Clark
- Department of Medicine, Section of Rheumatology, and Gwen Knapp Center for Lupus and Immunology Research, University of Chicago, Chicago, IL, USA.
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17
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Liang Z, Zhao L, Ye AY, Lin SG, Zhang Y, Guo C, Dai HQ, Ba Z, Alt FW. Contribution of the IGCR1 regulatory element and the 3' Igh CTCF-binding elements to regulation of Igh V(D)J recombination. Proc Natl Acad Sci U S A 2023; 120:e2306564120. [PMID: 37339228 PMCID: PMC10293834 DOI: 10.1073/pnas.2306564120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 05/12/2023] [Indexed: 06/22/2023] Open
Abstract
Immunoglobulin heavy chain variable region exons are assembled in progenitor-B cells, from VH, D, and JH gene segments located in separate clusters across the Igh locus. RAG endonuclease initiates V(D)J recombination from a JH-based recombination center (RC). Cohesin-mediated extrusion of upstream chromatin past RC-bound RAG presents Ds for joining to JHs to form a DJH-RC. Igh has a provocative number and organization of CTCF-binding elements (CBEs) that can impede loop extrusion. Thus, Igh has two divergently oriented CBEs (CBE1 and CBE2) in the IGCR1 element between the VH and D/JH domains, over 100 CBEs across the VH domain convergent to CBE1, and 10 clustered 3'Igh-CBEs convergent to CBE2 and VH CBEs. IGCR1 CBEs segregate D/JH and VH domains by impeding loop extrusion-mediated RAG-scanning. Downregulation of WAPL, a cohesin unloader, in progenitor-B cells neutralizes CBEs, allowing DJH-RC-bound RAG to scan the VH domain and perform VH-to-DJH rearrangements. To elucidate potential roles of IGCR1-based CBEs and 3'Igh-CBEs in regulating RAG-scanning and elucidate the mechanism of the ordered transition from D-to-JH to VH-to-DJH recombination, we tested effects of inverting and/or deleting IGCR1 or 3'Igh-CBEs in mice and/or progenitor-B cell lines. These studies revealed that normal IGCR1 CBE orientation augments RAG-scanning impediment activity and suggest that 3'Igh-CBEs reinforce ability of the RC to function as a dynamic loop extrusion impediment to promote optimal RAG scanning activity. Finally, our findings indicate that ordered V(D)J recombination can be explained by a gradual WAPL downregulation mechanism in progenitor-B cells as opposed to a strict developmental switch.
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Affiliation(s)
- Zhuoyi Liang
- HHMI, Boston Children’s Hospital, Boston, MA02115
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA02115
- Department of Genetics, Harvard Medical School, Boston, MA02115
| | - Lijuan Zhao
- HHMI, Boston Children’s Hospital, Boston, MA02115
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA02115
- Department of Genetics, Harvard Medical School, Boston, MA02115
| | - Adam Yongxin Ye
- HHMI, Boston Children’s Hospital, Boston, MA02115
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA02115
- Department of Genetics, Harvard Medical School, Boston, MA02115
| | - Sherry G. Lin
- HHMI, Boston Children’s Hospital, Boston, MA02115
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA02115
- Department of Genetics, Harvard Medical School, Boston, MA02115
| | - Yiwen Zhang
- HHMI, Boston Children’s Hospital, Boston, MA02115
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA02115
- Department of Genetics, Harvard Medical School, Boston, MA02115
| | - Chunguang Guo
- HHMI, Boston Children’s Hospital, Boston, MA02115
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA02115
- Department of Genetics, Harvard Medical School, Boston, MA02115
| | - Hai-Qiang Dai
- HHMI, Boston Children’s Hospital, Boston, MA02115
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA02115
- Department of Genetics, Harvard Medical School, Boston, MA02115
| | - Zhaoqing Ba
- HHMI, Boston Children’s Hospital, Boston, MA02115
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA02115
- Department of Genetics, Harvard Medical School, Boston, MA02115
| | - Frederick W. Alt
- HHMI, Boston Children’s Hospital, Boston, MA02115
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA02115
- Department of Genetics, Harvard Medical School, Boston, MA02115
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18
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Kiefer L, Chiosso A, Langen J, Buckley A, Gaudin S, Rajkumar SM, Servito GIF, Cha ES, Vijay A, Yeung A, Horta A, Mui MH, Canzio D. WAPL functions as a rheostat of Protocadherin isoform diversity that controls neural wiring. Science 2023; 380:eadf8440. [PMID: 37347873 DOI: 10.1126/science.adf8440] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 05/07/2023] [Indexed: 06/24/2023]
Abstract
Neural type-specific expression of clustered Protocadherin (Pcdh) proteins is essential for the establishment of connectivity patterns during brain development. In mammals, deterministic expression of the same Pcdh isoform promotes minimal overlap of tiled projections of serotonergic neuron axons throughout the brain, while stochastic expression of Pcdh genes allows for convergence of tightly packed, overlapping olfactory sensory neuron axons into targeted structures. How can the same gene locus generate opposite transcriptional programs that orchestrate distinct spatial arrangements of axonal patterns? Here, we reveal that cell type-specific Pcdh expression and axonal behavior depend on the activity of cohesin and its unloader, WAPL (wings apart-like protein homolog). While cohesin erases genomic-distance biases in Pcdh choice, WAPL functions as a rheostat of cohesin processivity that determines Pcdh isoform diversity.
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Affiliation(s)
- Lea Kiefer
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Anna Chiosso
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jennifer Langen
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Alex Buckley
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Simon Gaudin
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
- Ecole Normale Superieure de Lyon, 69432 Lyon, France
| | - Sandy M Rajkumar
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Gabrielle Isabelle F Servito
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Elizabeth S Cha
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Akshara Vijay
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Albert Yeung
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Adan Horta
- Pura Vida Investments, New York, NY 10106, USA
| | - Michael H Mui
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Daniele Canzio
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
- Chan-Zuckerberg Biohub, San Francisco, CA 94158, USA
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19
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Liang Z, Zhao L, Yongxin Ye A, Lin SG, Zhang Y, Guo C, Dai HQ, Ba Z, Alt FW. Contribution of the IGCR1 regulatory element and the 3 'Igh CBEs to Regulation of Igh V(D)J Recombination. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.21.537836. [PMID: 37163018 PMCID: PMC10168220 DOI: 10.1101/2023.04.21.537836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Immunoglobulin heavy chain variable region exons are assembled in progenitor-B cells, from V H , D, and J H gene segments located in separate clusters across the Igh locus. RAG endonuclease initiates V(D)J recombination from a J H -based recombination center (RC). Cohesin-mediated extrusion of upstream chromatin past RC-bound RAG presents Ds for joining to J H s to form a DJ H -RC. Igh has a provocative number and organization of CTCF-binding-elements (CBEs) that can impede loop extrusion. Thus, Igh has two divergently oriented CBEs (CBE1 and CBE2) in the IGCR1 element between the V H and D/J H domains, over 100 CBEs across the V H domain convergent to CBE1, and 10 clustered 3' Igh -CBEs convergent to CBE2 and V H CBEs. IGCR1 CBEs segregate D/J H and V H domains by impeding loop extrusion-mediated RAG-scanning. Down-regulation of WAPL, a cohesin unloader, in progenitor-B cells neutralizes CBEs, allowing DJ H -RC-bound RAG to scan the VH domain and perform VH-to-DJH rearrangements. To elucidate potential roles of IGCR1-based CBEs and 3' Igh -CBEs in regulating RAG-scanning and elucidate the mechanism of the "ordered" transition from D-to-J H to V H -to-DJ H recombination, we tested effects of deleting or inverting IGCR1 or 3' Igh -CBEs in mice and/or progenitor-B cell lines. These studies revealed that normal IGCR1 CBE orientation augments RAG-scanning impediment activity and suggest that 3' Igh -CBEs reinforce ability of the RC to function as a dynamic loop extrusion impediment to promote optimal RAG scanning activity. Finally, our findings indicate that ordered V(D)J recombination can be explained by a gradual WAPL down-regulation mechanism in progenitor B cells as opposed to a strict developmental switch. SIGNIFICANCE STATEMENT To counteract diverse pathogens, vertebrates evolved adaptive immunity to generate diverse antibody repertoires through a B lymphocyte-specific somatic gene rearrangement process termed V(D)J recombination. Tight regulation of the V(D)J recombination process is vital to generating antibody diversity and preventing off-target activities that can predispose the oncogenic translocations. Recent studies have demonstrated V(D)J rearrangement is driven by cohesin-mediated chromatin loop extrusion, a process that establishes genomic loop domains by extruding chromatin, predominantly, between convergently-oriented CTCF looping factor-binding elements (CBEs). By deleting and inverting CBEs within a critical antibody heavy chain gene locus developmental control region and a loop extrusion chromatin-anchor at the downstream end of this locus, we reveal how these elements developmentally contribute to generation of diverse antibody repertoires.
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20
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Hill L, Wutz G, Jaritz M, Tagoh H, Calderón L, Peters JM, Goloborodko A, Busslinger M. Igh and Igk loci use different folding principles for V gene recombination due to distinct chromosomal architectures of pro-B and pre-B cells. Nat Commun 2023; 14:2316. [PMID: 37085514 PMCID: PMC10121685 DOI: 10.1038/s41467-023-37994-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 04/04/2023] [Indexed: 04/23/2023] Open
Abstract
Extended loop extrusion across the immunoglobulin heavy-chain (Igh) locus facilitates VH-DJH recombination following downregulation of the cohesin-release factor Wapl by Pax5, resulting in global changes in the chromosomal architecture of pro-B cells. Here, we demonstrate that chromatin looping and VK-JK recombination at the Igk locus were insensitive to Wapl upregulation in pre-B cells. Notably, the Wapl protein was expressed at a 2.2-fold higher level in pre-B cells compared with pro-B cells, which resulted in a distinct chromosomal architecture with normal loop sizes in pre-B cells. High-resolution chromosomal contact analysis of the Igk locus identified multiple internal loops, which likely juxtapose VK and JK elements to facilitate VK-JK recombination. The higher Wapl expression in Igμ-transgenic pre-B cells prevented extended loop extrusion at the Igh locus, leading to recombination of only the 6 most 3' proximal VH genes and likely to allelic exclusion of all other VH genes in pre-B cells. These results suggest that pro-B and pre-B cells with their distinct chromosomal architectures use different chromatin folding principles for V gene recombination, thereby enabling allelic exclusion at the Igh locus, when the Igk locus is recombined.
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Affiliation(s)
- Louisa Hill
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, A-1030, Vienna, Austria
| | - Gordana Wutz
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, A-1030, Vienna, Austria
| | - Markus Jaritz
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, A-1030, Vienna, Austria
| | - Hiromi Tagoh
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, A-1030, Vienna, Austria
| | - Lesly Calderón
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, A-1030, Vienna, Austria
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, A-1030, Vienna, Austria
| | - Anton Goloborodko
- Institute of Molecular Biotechnology (IMBA), Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, A-1030, Vienna, Austria
| | - Meinrad Busslinger
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, A-1030, Vienna, Austria.
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21
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Yang JH, Brandão HB, Hansen AS. DNA double-strand break end synapsis by DNA loop extrusion. Nat Commun 2023; 14:1913. [PMID: 37024496 PMCID: PMC10079674 DOI: 10.1038/s41467-023-37583-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 03/23/2023] [Indexed: 04/08/2023] Open
Abstract
DNA double-strand breaks (DSBs) occur every cell cycle and must be efficiently repaired. Non-homologous end joining (NHEJ) is the dominant pathway for DSB repair in G1-phase. The first step of NHEJ is to bring the two DSB ends back into proximity (synapsis). Although synapsis is generally assumed to occur through passive diffusion, we show that passive diffusion is unlikely to produce the synapsis speed observed in cells. Instead, we hypothesize that DNA loop extrusion facilitates synapsis. By combining experimentally constrained simulations and theory, we show that a simple loop extrusion model constrained by previous live-cell imaging data only modestly accelerates synapsis. Instead, an expanded loop extrusion model with targeted loading of loop extruding factors (LEFs), a small portion of long-lived LEFs, and LEF stabilization by boundary elements and DSB ends achieves fast synapsis with near 100% efficiency. We propose that loop extrusion contributes to DSB repair by mediating fast synapsis.
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Affiliation(s)
- Jin H Yang
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Koch Institute for Integrative Cancer Research, Cambridge, MA, 02142, USA
| | - Hugo B Brandão
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
- The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.
- Koch Institute for Integrative Cancer Research, Cambridge, MA, 02142, USA.
- Illumina Inc., San Diego, CA, 92122, USA.
| | - Anders S Hansen
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
- The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.
- Koch Institute for Integrative Cancer Research, Cambridge, MA, 02142, USA.
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22
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Bhat KH, Priyadarshi S, Naiyer S, Qu X, Farooq H, Kleiman E, Xu J, Lei X, Cantillo JF, Wuerffel R, Baumgarth N, Liang J, Feeney AJ, Kenter AL. An Igh distal enhancer modulates antigen receptor diversity by determining locus conformation. Nat Commun 2023; 14:1225. [PMID: 36869028 PMCID: PMC9984487 DOI: 10.1038/s41467-023-36414-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 01/31/2023] [Indexed: 03/05/2023] Open
Abstract
The mouse Igh locus is organized into a developmentally regulated topologically associated domain (TAD) that is divided into subTADs. Here we identify a series of distal VH enhancers (EVHs) that collaborate to configure the locus. EVHs engage in a network of long-range interactions that interconnect the subTADs and the recombination center at the DHJH gene cluster. Deletion of EVH1 reduces V gene rearrangement in its vicinity and alters discrete chromatin loops and higher order locus conformation. Reduction in the rearrangement of the VH11 gene used in anti-PtC responses is a likely cause of the observed reduced splenic B1 B cell compartment. EVH1 appears to block long-range loop extrusion that in turn contributes to locus contraction and determines the proximity of distant VH genes to the recombination center. EVH1 is a critical architectural and regulatory element that coordinates chromatin conformational states that favor V(D)J rearrangement.
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Affiliation(s)
- Khalid H Bhat
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL, 60612-7344, USA
- SKUAST Kashmir, Division of Basic Science and Humanities, Faculty of Agriculture, Wadura Sopore-193201, Wadoora, India
| | - Saurabh Priyadarshi
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL, 60612-7344, USA
| | - Sarah Naiyer
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL, 60612-7344, USA
| | - Xinyan Qu
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL, 60612-7344, USA
- Medpace, Cincinnati, Ohio, 45227, USA
| | - Hammad Farooq
- Department of Bioengineering, University of Illinois Colleges of Engineering and Medicine, Chicago, IL, 60612-7344, USA
| | - Eden Kleiman
- Department of Immunology and Microbiology, IMM-22, Scripps Research, La Jolla, CA, 92037, USA
- Crown Bioscience, San Diego, CA, 92127, USA
| | - Jeffery Xu
- Department of Immunology and Microbiology, IMM-22, Scripps Research, La Jolla, CA, 92037, USA
- Brookwood Baptist Health General Surgery Residency, Birmingham, AL, 35211, USA
| | - Xue Lei
- Department of Bioengineering, University of Illinois Colleges of Engineering and Medicine, Chicago, IL, 60612-7344, USA
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Jose F Cantillo
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL, 60612-7344, USA
- Immunotek, S.L. Alcala de Henares, Spain
| | - Robert Wuerffel
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL, 60612-7344, USA
- 10441 Circle Dr. Apt 47C, Oak Lawn, IL, 60453, USA
| | - Nicole Baumgarth
- W. Harry Feinstone Dept. Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, USA
| | - Jie Liang
- Department of Bioengineering, University of Illinois Colleges of Engineering and Medicine, Chicago, IL, 60612-7344, USA
| | - Ann J Feeney
- Department of Immunology and Microbiology, IMM-22, Scripps Research, La Jolla, CA, 92037, USA
| | - Amy L Kenter
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL, 60612-7344, USA.
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23
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Kenter AL, Priyadarshi S, Drake EB. Locus architecture and RAG scanning determine antibody diversity. Trends Immunol 2023; 44:119-128. [PMID: 36706738 PMCID: PMC10128066 DOI: 10.1016/j.it.2022.12.005] [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: 12/01/2022] [Revised: 12/07/2022] [Accepted: 12/08/2022] [Indexed: 01/27/2023]
Abstract
Diverse mammalian antibody repertoires are produced via distant genomic contacts involving immunoglobulin Igh variable (V), diversity (D), and joining (J) gene segments and result in V(D)J recombination. How such interactions determine V gene usage remains unclear. The recombination-activating gene (RAG) chromatin scanning model posits that RAG recombinase bound to the recombination center (RC) linearly tracks along chromatin by means of cohesin-mediated loop extrusion; a proposition supported by cohesin depletion studies. A mechanistic role for chromatin loop extrusion has also been implicated for Igh locus contraction. In this opinion, we provide perspective on how loop extrusion interfaces with the 3D conformation of the Igh locus and newly identified enhancers that regionally regulate VH gene usage during V(D)J recombination, shaping the preselected repertoire.
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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.
| | - Saurabh Priyadarshi
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL 60612-7344, USA
| | - Ellen B Drake
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL 60612-7344, USA
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24
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Barajas-Mora EM, Lee L, Lu H, Valderrama JA, Bjanes E, Nizet V, Feeney AJ, Hu M, Murre C. Enhancer-instructed epigenetic landscape and chromatin compartmentalization dictate a primary antibody repertoire protective against specific bacterial pathogens. Nat Immunol 2023; 24:320-336. [PMID: 36717722 PMCID: PMC10917333 DOI: 10.1038/s41590-022-01402-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 12/06/2022] [Indexed: 01/31/2023]
Abstract
Antigen receptor loci are organized into variable (V), diversity (D) and joining (J) gene segments that rearrange to generate antigen receptor repertoires. Here, we identified an enhancer (E34) in the murine immunoglobulin kappa (Igk) locus that instructed rearrangement of Vκ genes located in a sub-topologically associating domain, including a Vκ gene encoding for antibodies targeting bacterial phosphorylcholine. We show that E34 instructs the nuclear repositioning of the E34 sub-topologically associating domain from a recombination-repressive compartment to a recombination-permissive compartment that is marked by equivalent activating histone modifications. Finally, we found that E34-instructed Vκ-Jκ rearrangement was essential to combat Streptococcus pneumoniae but not methicillin-resistant Staphylococcus aureus or influenza infections. We propose that the merging of Vκ genes with Jκ elements is instructed by one-dimensional epigenetic information imposed by enhancers across Vκ and Jκ genomic regions. The data also reveal how enhancers generate distinct antibody repertoires that provide protection against lethal bacterial infection.
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Affiliation(s)
| | - Lindsay Lee
- Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Hanbin Lu
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA, USA
| | - J Andrés Valderrama
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
| | - Elisabet Bjanes
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
| | - Victor Nizet
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, USA
| | - Ann J Feeney
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA, USA
| | - Ming Hu
- Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA.
| | - Cornelis Murre
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA, USA.
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25
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de Wit E, Nora EP. New insights into genome folding by loop extrusion from inducible degron technologies. Nat Rev Genet 2023; 24:73-85. [PMID: 36180596 DOI: 10.1038/s41576-022-00530-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2022] [Indexed: 01/24/2023]
Abstract
Chromatin folds into dynamic loops that often span hundreds of kilobases and physically wire distant loci together for gene regulation. These loops are continuously created, extended and positioned by structural maintenance of chromosomes (SMC) protein complexes, such as condensin and cohesin, and their regulators, including CTCF, in a highly dynamic process known as loop extrusion. Genetic loss of extrusion factors is lethal, complicating their study. Inducible protein degradation technologies enable the depletion of loop extrusion factors within hours, leading to the rapid reconfiguration of chromatin folding. Here, we review how these technologies have changed our understanding of genome organization, upsetting long-held beliefs on its role in transcription. Finally, we examine recent models that attempt to reconcile observations after chronic versus acute perturbations, and discuss future developments in this rapidly developing field of research.
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Affiliation(s)
- Elzo de Wit
- Division of Gene Regulation, Oncode Institute, Amsterdam, the Netherlands.
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Elphège P Nora
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA.
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.
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26
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Luo S, Jing C, Ye AY, Kratochvil S, Cottrell CA, Koo JH, Chapdelaine Williams A, Francisco LV, Batra H, Lamperti E, Kalyuzhniy O, Zhang Y, Barbieri A, Manis JP, Haynes BF, Schief WR, Batista FD, Tian M, Alt FW. Humanized V(D)J-rearranging and TdT-expressing mouse vaccine models with physiological HIV-1 broadly neutralizing antibody precursors. Proc Natl Acad Sci U S A 2023; 120:e2217883120. [PMID: 36574685 PMCID: PMC9910454 DOI: 10.1073/pnas.2217883120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 11/22/2022] [Indexed: 12/28/2022] Open
Abstract
Antibody heavy chain (HC) and light chain (LC) variable region exons are assembled by V(D)J recombination. V(D)J junctional regions encode complementarity-determining-region 3 (CDR3), an antigen-contact region immensely diversified through nontemplated nucleotide additions ("N-regions") by terminal deoxynucleotidyl transferase (TdT). HIV-1 vaccine strategies seek to elicit human HIV-1 broadly neutralizing antibodies (bnAbs), such as the potent CD4-binding site VRC01-class bnAbs. Mice with primary B cells that express receptors (BCRs) representing bnAb precursors are used as vaccination models. VRC01-class bnAbs uniformly use human HC VH1-2 and commonly use human LCs Vκ3-20 or Vκ1-33 associated with an exceptionally short 5-amino-acid (5-aa) CDR3. Prior VRC01-class models had nonphysiological precursor levels and/or limited precursor diversity. Here, we describe VRC01-class rearranging mice that generate more physiological primary VRC01-class BCR repertoires via rearrangement of VH1-2, as well as Vκ1-33 and/or Vκ3-20 in association with diverse CDR3s. Human-like TdT expression in mouse precursor B cells increased LC CDR3 length and diversity and also promoted the generation of shorter LC CDR3s via N-region suppression of dominant microhomology-mediated Vκ-to-Jκ joins. Priming immunization with eOD-GT8 60mer, which strongly engages VRC01 precursors, induced robust VRC01-class germinal center B cell responses. Vκ3-20-based responses were enhanced by N-region addition, which generates Vκ3-20-to-Jκ junctional sequence combinations that encode VRC01-class 5-aa CDR3s with a critical E residue. VRC01-class-rearranging models should facilitate further evaluation of VRC01-class prime and boost immunogens. These new VRC01-class mouse models establish a prototype for the generation of vaccine-testing mouse models for other HIV-1 bnAb lineages that employ different HC or LC Vs.
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Affiliation(s)
- Sai Luo
- HHMI, Boston Children's Hospital, Boston, MA 02115
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Changbin Jing
- HHMI, Boston Children's Hospital, Boston, MA 02115
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Adam Yongxin Ye
- HHMI, Boston Children's Hospital, Boston, MA 02115
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Sven Kratochvil
- The Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA 02139
| | - Christopher A Cottrell
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, San Diego, CA 92037
- IAVI Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, San Diego, CA 92037
- Center for HIV/AIDS Vaccine Development, The Scripps Research Institute, La Jolla, San Diego, CA 92037
| | - Ja-Hyun Koo
- The Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA 02139
| | - Aimee Chapdelaine Williams
- HHMI, Boston Children's Hospital, Boston, MA 02115
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Lucas Vieira Francisco
- HHMI, Boston Children's Hospital, Boston, MA 02115
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Himanshu Batra
- HHMI, Boston Children's Hospital, Boston, MA 02115
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Edward Lamperti
- The Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA 02139
| | - Oleksandr Kalyuzhniy
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, San Diego, CA 92037
- IAVI Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, San Diego, CA 92037
- Center for HIV/AIDS Vaccine Development, The Scripps Research Institute, La Jolla, San Diego, CA 92037
| | - Yuxiang Zhang
- HHMI, Boston Children's Hospital, Boston, MA 02115
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Alessandro Barbieri
- Department of Laboratory Medicine, Boston Children's Hospital, Boston, MA 02115
| | - John P Manis
- Department of Laboratory Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Barton F Haynes
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710
- Department of Immunology, Duke University School of Medicine, Durham, NC 27710
| | - William R Schief
- The Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA 02139
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, San Diego, CA 92037
- IAVI Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, San Diego, CA 92037
- Center for HIV/AIDS Vaccine Development, The Scripps Research Institute, La Jolla, San Diego, CA 92037
| | - Facundo D Batista
- The Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA 02139
- Department of Immunology, Harvard Medical School, Boston, MA 02115
- Department of Microbiology, Harvard Medical School, Boston, MA 02115
| | - Ming Tian
- HHMI, Boston Children's Hospital, Boston, MA 02115
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Frederick W Alt
- HHMI, Boston Children's Hospital, Boston, MA 02115
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
- Department of Genetics, Harvard Medical School, Boston, MA 02115
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27
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Zagelbaum J, Gautier J. Double-strand break repair and mis-repair in 3D. DNA Repair (Amst) 2023; 121:103430. [PMID: 36436496 PMCID: PMC10799305 DOI: 10.1016/j.dnarep.2022.103430] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/13/2022] [Accepted: 11/15/2022] [Indexed: 11/18/2022]
Abstract
DNA double-strand breaks (DSBs) are lesions that arise frequently from exposure to damaging agents as well as from ongoing physiological DNA transactions. Mis-repair of DSBs leads to rearrangements and structural variations in chromosomes, including insertions, deletions, and translocations implicated in disease. The DNA damage response (DDR) limits pathologic mutations and large-scale chromosome rearrangements. DSB repair initiates in 2D at DNA lesions with the stepwise recruitment of repair proteins and local chromatin remodeling which facilitates break accessibility. More complex structures are then formed via protein assembly into nanodomains and via genome folding into chromatin loops. Subsequently, 3D reorganization of DSBs is guided by clustering forces which drive the assembly of repair domains harboring multiple lesions. These domains are further stabilized and insulated into condensates via liquid-liquid phase-separation. Here, we discuss the benefits and risks associated with this 3D reorganization of the broken genome.
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Affiliation(s)
- Jennifer Zagelbaum
- Institute for Cancer Genetics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA; Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Jean Gautier
- Institute for Cancer Genetics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA; Department of Genetics and Development, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA.
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28
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Zagelbaum J, Schooley A, Zhao J, Schrank BR, Callen E, Zha S, Gottesman ME, Nussenzweig A, Rabadan R, Dekker J, Gautier J. Multiscale reorganization of the genome following DNA damage facilitates chromosome translocations via nuclear actin polymerization. Nat Struct Mol Biol 2023; 30:99-106. [PMID: 36564591 PMCID: PMC10104780 DOI: 10.1038/s41594-022-00893-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 11/04/2022] [Indexed: 12/24/2022]
Abstract
Nuclear actin-based movements have been shown to orchestrate clustering of DNA double-strand breaks (DSBs) into homology-directed repair domains. Here we describe multiscale three-dimensional genome reorganization following DNA damage and analyze the contribution of the nuclear WASP-ARP2/3-actin pathway toward chromatin topology alterations and pathologic repair. Hi-C analysis reveals genome-wide, DNA damage-induced chromatin compartment flips facilitated by ARP2/3 that enrich for open, A compartments. Damage promotes interactions between DSBs, which in turn facilitate aberrant, actin-dependent intra- and inter-chromosomal rearrangements. Our work establishes that clustering of resected DSBs into repair domains by nuclear actin assembly is coordinated with multiscale alterations in genome architecture that enable homology-directed repair while also increasing nonhomologous end-joining-dependent translocation frequency.
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Affiliation(s)
- Jennifer Zagelbaum
- Institute for Cancer Genetics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Allana Schooley
- Department of Systems Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Junfei Zhao
- Department of Systems Biology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Benjamin R Schrank
- Institute for Cancer Genetics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Elsa Callen
- Laboratory of Genome Integrity, National Institutes of Health, Bethesda, MD, USA
| | - Shan Zha
- Institute for Cancer Genetics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Department of Pathology and Cell Biology and Department of Pediatrics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Max E Gottesman
- Department of Biochemistry and Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - André Nussenzweig
- Laboratory of Genome Integrity, National Institutes of Health, Bethesda, MD, USA
| | - Raul Rabadan
- Department of Systems Biology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Job Dekker
- Department of Systems Biology, University of Massachusetts Medical School, Worcester, MA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Jean Gautier
- Institute for Cancer Genetics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA.
- Herbert Irving Comprehensive Cancer Center, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA.
- Department of Genetics and Development, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA.
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29
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Belcheva KT, Chaudhuri J. Maintenance of Lineage Identity: Lessons from a B Cell. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 209:2073-2081. [PMID: 36426973 DOI: 10.4049/jimmunol.2200497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 08/17/2022] [Indexed: 01/04/2023]
Abstract
The maintenance of B cell identity requires active transcriptional control that enforces a B cell-specific program and suppresses alternative lineage genes. Accordingly, disrupting the B cell identity regulatory network compromises B cell function and induces cell fate plasticity by allowing derepression of alternative lineage-specific transcriptional programs. Although the B lineage is incredibly resistant to most differentiating factors, loss of just a single B lineage-specific transcription factor or the forced expression of individual non-B cell lineage transcription factors can radically disrupt B cell maintenance and allow dedifferentiation or transdifferentiation into entirely distinct lineages. B lymphocytes thereby offer an insightful and useful case study of how a specific cell lineage can maintain a stable identity throughout life and how perturbations of a single master regulator can induce cellular plasticity. In this article, we review the regulatory mechanisms that safeguard B cell identity, and we discuss how dysregulation of the B cell maintenance program can drive malignant transformation and enable therapeutic resistance.
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Affiliation(s)
- Kalina T Belcheva
- Biochemistry, Cellular and Molecular Biology Allied Program, Weill Cornell Graduate School of Medical Sciences, New York, NY; and
| | - Jayanta Chaudhuri
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY
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30
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Liu S, Cao Y, Cui K, Tang Q, Zhao K. Hi-TrAC reveals division of labor of transcription factors in organizing chromatin loops. Nat Commun 2022; 13:6679. [PMID: 36335136 PMCID: PMC9637178 DOI: 10.1038/s41467-022-34276-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 10/20/2022] [Indexed: 11/08/2022] Open
Abstract
The three-dimensional genomic structure plays a critical role in gene expression, cellular differentiation, and pathological conditions. It is pivotal to elucidate fine-scale chromatin architectures, especially interactions of regulatory elements, to understand the temporospatial regulation of gene expression. In this study, we report Hi-TrAC as a proximity ligation-free, robust, and sensitive technique to profile genome-wide chromatin interactions at high-resolution among regulatory elements. Hi-TrAC detects chromatin looping among accessible regions at single nucleosome resolution. With almost half-million identified loops, we reveal a comprehensive interaction network of regulatory elements across the genome. After integrating chromatin binding profiles of transcription factors, we discover that cohesin complex and CTCF are responsible for organizing long-range chromatin loops, related to domain formation; whereas ZNF143 and HCFC1 are involved in structuring short-range chromatin loops between regulatory elements, which directly regulate gene expression. Thus, we introduce a methodology to identify a delicate and comprehensive network of cis-regulatory elements, revealing the complexity and a division of labor of transcription factors in organizing chromatin loops for genome organization and gene expression.
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Affiliation(s)
- Shuai Liu
- grid.94365.3d0000 0001 2297 5165Laboratory of Epigenome Biology, Systems Biology Center, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD USA
| | - Yaqiang Cao
- grid.94365.3d0000 0001 2297 5165Laboratory of Epigenome Biology, Systems Biology Center, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD USA
| | - Kairong Cui
- grid.94365.3d0000 0001 2297 5165Laboratory of Epigenome Biology, Systems Biology Center, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD USA
| | - Qingsong Tang
- grid.94365.3d0000 0001 2297 5165Laboratory of Epigenome Biology, Systems Biology Center, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD USA
| | - Keji Zhao
- grid.94365.3d0000 0001 2297 5165Laboratory of Epigenome Biology, Systems Biology Center, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD USA
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Luo S, Zhang J, Kreutzberger AJ, Eaton A, Edwards RJ, Jing C, Dai HQ, Sempowski GD, Cronin K, Parks R, Ye AY, Mansouri K, Barr M, Pishesha N, Williams AC, Vieira Francisco L, Saminathan A, Peng H, Batra H, Bellusci L, Khurana S, Alam SM, Montefiori DC, Saunders KO, Tian M, Ploegh H, Kirchhausen T, Chen B, Haynes BF, Alt FW. An antibody from single human V H-rearranging mouse neutralizes all SARS-CoV-2 variants through BA.5 by inhibiting membrane fusion. Sci Immunol 2022; 7:eadd5446. [PMID: 35951767 PMCID: PMC9407951 DOI: 10.1126/sciimmunol.add5446] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 08/03/2022] [Indexed: 12/14/2022]
Abstract
SARS-CoV-2 Omicron subvariants have generated a worldwide health crisis due to resistance to most approved SARS-CoV-2 neutralizing antibodies and evasion of vaccination-induced antibodies. To manage Omicron subvariants and prepare for new ones, additional means of isolating broad and potent humanized SARS-CoV-2 neutralizing antibodies are desirable. Here, we describe a mouse model in which the primary B cell receptor (BCR) repertoire is generated solely through V(D)J recombination of a human VH1-2 heavy chain (HC) and, substantially, a human Vκ1-33 light chain (LC). Thus, primary humanized BCR repertoire diversity in these mice derives from immensely diverse HC and LC antigen-contact CDR3 sequences generated by nontemplated junctional modifications during V(D)J recombination. Immunizing this mouse model with SARS-CoV-2 (Wuhan-Hu-1) spike protein immunogens elicited several VH1-2/Vκ1-33-based neutralizing antibodies that bound RBD in a different mode from each other and from those of many prior patient-derived VH1-2-based neutralizing antibodies. Of these, SP1-77 potently and broadly neutralized all SARS-CoV-2 variants through BA.5. Cryo-EM studies revealed that SP1-77 bound RBD away from the receptor-binding motif via a CDR3-dominated recognition mode. Lattice light-sheet microscopy-based studies showed that SP1-77 did not block ACE2-mediated viral attachment or endocytosis but rather blocked viral-host membrane fusion. The broad and potent SP1-77 neutralization activity and nontraditional mechanism of action suggest that it might have therapeutic potential. Likewise, the SP1-77 binding epitope may inform vaccine strategies. Last, the type of humanized mouse models that we have described may contribute to identifying therapeutic antibodies against future SARS-CoV-2 variants and other pathogens.
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Affiliation(s)
- Sai Luo
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Jun Zhang
- Division of Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Alex J.B. Kreutzberger
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Amanda Eaton
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Robert J. Edwards
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Changbin Jing
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Hai-Qiang Dai
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Gregory D. Sempowski
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kenneth Cronin
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Robert Parks
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Adam Yongxin Ye
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Katayoun Mansouri
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Maggie Barr
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Novalia Pishesha
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Aimee Chapdelaine Williams
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Lucas Vieira Francisco
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Anand Saminathan
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Hanqin Peng
- Division of Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Himanshu Batra
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Lorenza Bellusci
- Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration (FDA), Silver Spring, MD, USA
| | - Surender Khurana
- Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration (FDA), Silver Spring, MD, USA
| | - S. Munir Alam
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - David C. Montefiori
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Surgery, Duke University, Durham, NC 27710, USA
| | - Kevin O. Saunders
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Surgery, Duke University, Durham, NC 27710, USA
- Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Ming Tian
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Hidde Ploegh
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Tom Kirchhausen
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Bing Chen
- Division of Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Barton F. Haynes
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Frederick W. Alt
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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The role of chromatin loop extrusion in antibody diversification. Nat Rev Immunol 2022; 22:550-566. [PMID: 35169260 PMCID: PMC9376198 DOI: 10.1038/s41577-022-00679-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/12/2022] [Indexed: 12/15/2022]
Abstract
Cohesin mediates chromatin loop formation across the genome by extruding chromatin between convergently oriented CTCF-binding elements. Recent studies indicate that cohesin-mediated loop extrusion in developing B cells presents immunoglobulin heavy chain (Igh) variable (V), diversity (D) and joining (J) gene segments to RAG endonuclease through a process referred to as RAG chromatin scanning. RAG initiates V(D)J recombinational joining of these gene segments to generate the large number of different Igh variable region exons that are required for immune responses to diverse pathogens. Antigen-activated mature B cells also use chromatin loop extrusion to mediate the synapsis, breakage and end joining of switch regions flanking Igh constant region exons during class-switch recombination, which allows for the expression of different antibody constant region isotypes that optimize the functions of antigen-specific antibodies to eliminate pathogens. Here, we review recent advances in our understanding of chromatin loop extrusion during V(D)J recombination and class-switch recombination at the Igh locus.
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Laffleur B, Batista CR, Zhang W, Lim J, Yang B, Rossille D, Wu L, Estrella J, Rothschild G, Pefanis E, Basu U. RNA exosome drives early B cell development via noncoding RNA processing mechanisms. Sci Immunol 2022; 7:eabn2738. [PMID: 35658015 DOI: 10.1126/sciimmunol.abn2738] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
B cell development is linked to successful V(D)J recombination, allowing B cell receptor expression and ultimately antibody secretion for adaptive immunity. Germline noncoding RNAs (ncRNAs) are produced at immunoglobulin (Ig) loci during V(D)J recombination, but their function and posttranscriptional regulation are incompletely understood. Patients with trichohepatoenteric syndrome, characterized by RNA exosome pathway component mutations, exhibit lymphopenia, thus demonstrating the importance of ncRNA surveillance in B cell development in humans. To understand the role of RNA exosome in early B cell development in greater detail, we generated mouse models harboring a B cell-specific cre allele (Mb1cre), coupled to conditional inversion-deletion alleles of one RNA exosome core component (Exosc3) or RNase catalytic subunits (Exosc10 or Dis3). We noticed increased expression of RNA exosome subunits during V(D)J recombination, whereas a B cell developmental blockade at the pro-B cell stage was observed in the different knockout mice, overlapping with a lack of productive rearrangements of VDJ genes at the Ig heavy chain (Igh). This unsuccessful recombination prevented differentiation into pre-B cells, with accumulation of ncRNAs and up-regulation of the p53 pathway. Introduction of a prearranged Igh VDJ allele partly rescued the pre-B cell population in Dis3-deficient cells, although V-J recombination defects were observed at Ig light chain kappa (Igκ), preventing subsequent B cell development. These observations demonstrated that the RNA exosome complex is important for Igh and Igκ recombination and establish the relevance of RNA processing for optimal diversification at these loci during B cell development.
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Affiliation(s)
- Brice Laffleur
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Carolina R Batista
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Wanwei Zhang
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Junghyun Lim
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Biao Yang
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Delphine Rossille
- Universite of Rennes, INSERM, EFS Bretagne, CHU Rennes, UMR 1236, Rennes, France
| | - Lijing Wu
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Jerson Estrella
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Gerson Rothschild
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | | | - Uttiya Basu
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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Bastié N, Chapard C, Dauban L, Gadal O, Beckouët F, Koszul R. Smc3 acetylation, Pds5 and Scc2 control the translocase activity that establishes cohesin-dependent chromatin loops. Nat Struct Mol Biol 2022; 29:575-585. [PMID: 35710835 DOI: 10.1038/s41594-022-00780-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 04/04/2022] [Indexed: 02/07/2023]
Abstract
Cohesin is a DNA translocase that is instrumental in the folding of the genome into chromatin loops, with functional consequences on DNA-related processes. Chromatin loop length and organization likely depend on cohesin processivity, translocation rate and stability on DNA. Here, we investigate and provide a comprehensive overview of the roles of various cohesin regulators in tuning chromatin loop expansion in budding yeast Saccharomyces cerevisiae. We demonstrate that Scc2, which stimulates cohesin ATPase activity, is also essential for cohesin translocation, driving loop expansion in vivo. Smc3 acetylation during the S phase counteracts this activity through the stabilization of Pds5, which finely tunes the size and stability of loops in G2.
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Affiliation(s)
- Nathalie Bastié
- Molecular, Cellular and Developmental biology department (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Christophe Chapard
- Institut Pasteur, CNRS UMR3525, Université Paris Cité, Unité Régulation Spatiale des Génomes, Paris, France
| | - Lise Dauban
- Molecular, Cellular and Developmental biology department (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
- Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Olivier Gadal
- Molecular, Cellular and Developmental biology department (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Frédéric Beckouët
- Molecular, Cellular and Developmental biology department (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France.
| | - Romain Koszul
- Institut Pasteur, CNRS UMR3525, Université Paris Cité, Unité Régulation Spatiale des Génomes, Paris, France.
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35
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Luo S, Qiao R, Zhang X. DNA Damage Response and Repair in Adaptive Immunity. Front Cell Dev Biol 2022; 10:884873. [PMID: 35663402 PMCID: PMC9157429 DOI: 10.3389/fcell.2022.884873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 03/31/2022] [Indexed: 11/16/2022] Open
Abstract
The diversification of B-cell receptor (BCR), as well as its secreted product, antibody, is a hallmark of adaptive immunity, which has more specific roles in fighting against pathogens. The antibody diversification is from recombination-activating gene (RAG)-initiated V(D)J recombination, activation-induced cytidine deaminase (AID)-initiated class switch recombination (CSR), and V(D)J exon somatic hypermutation (SHM). The proper repair of RAG- and AID-initiated DNA lesions and double-strand breaks (DSBs) is required for promoting antibody diversification, suppressing genomic instability, and oncogenic translocations. DNA damage response (DDR) factors and DSB end-joining factors are recruited to the RAG- and AID-initiated DNA lesions and DSBs to coordinately resolve them for generating productive recombination products during antibody diversification. Recently, cohesin-mediated loop extrusion is proposed to be the underlying mechanism of V(D)J recombination and CSR, which plays essential roles in promoting the orientation-biased deletional end-joining . Here, we will discuss the mechanism of DNA damage repair in antibody diversification.
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Affiliation(s)
- Sha Luo
- Biomedical Pioneering Innovation Center, Innovation Center for Genomics, Peking University, Beijing, China
- Academy for Advanced Interdisciplinery Studies, Peking University, Beijing, China
| | - Ruolin Qiao
- Biomedical Pioneering Innovation Center, Innovation Center for Genomics, Peking University, Beijing, China
- Academy for Advanced Interdisciplinery Studies, Peking University, Beijing, China
| | - Xuefei Zhang
- Biomedical Pioneering Innovation Center, Innovation Center for Genomics, Peking University, Beijing, China
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36
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Christie SM, Fijen C, Rothenberg E. V(D)J Recombination: Recent Insights in Formation of the Recombinase Complex and Recruitment of DNA Repair Machinery. Front Cell Dev Biol 2022; 10:886718. [PMID: 35573672 PMCID: PMC9099191 DOI: 10.3389/fcell.2022.886718] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/01/2022] [Indexed: 11/13/2022] Open
Abstract
V(D)J recombination is an essential mechanism of the adaptive immune system, producing a diverse set of antigen receptors in developing lymphocytes via regulated double strand DNA break and subsequent repair. DNA cleavage is initiated by the recombinase complex, consisting of lymphocyte specific proteins RAG1 and RAG2, while the repair phase is completed by classical non-homologous end joining (NHEJ). Many of the individual steps of this process have been well described and new research has increased the scale to understand the mechanisms of initiation and intermediate stages of the pathway. In this review we discuss 1) the regulatory functions of RAGs, 2) recruitment of RAGs to the site of recombination and formation of a paired complex, 3) the transition from a post-cleavage complex containing RAGs and cleaved DNA ends to the NHEJ repair phase, and 4) the potential redundant roles of certain factors in repairing the break. Regulatory (non-core) domains of RAGs are not necessary for catalytic activity, but likely influence recruitment and stabilization through interaction with modified histones and conformational changes. To form long range paired complexes, recent studies have found evidence in support of large scale chromosomal contraction through various factors to utilize diverse gene segments. Following the paired cleavage event, four broken DNA ends must now make a regulated transition to the repair phase, which can be controlled by dynamic conformational changes and post-translational modification of the factors involved. Additionally, we examine the overlapping roles of certain NHEJ factors which allows for prevention of genomic instability due to incomplete repair in the absence of one, but are lethal in combined knockouts. To conclude, we focus on the importance of understanding the detail of these processes in regards to off-target recombination or deficiency-mediated clinical manifestations.
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Affiliation(s)
- Shaun M. Christie
- *Correspondence: Shaun M. Christie, ; Carel Fijen, ; Eli Rothenberg,
| | - Carel Fijen
- *Correspondence: Shaun M. Christie, ; Carel Fijen, ; Eli Rothenberg,
| | - Eli Rothenberg
- *Correspondence: Shaun M. Christie, ; Carel Fijen, ; Eli Rothenberg,
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37
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A walk through the SMC cycle: From catching DNAs to shaping the genome. Mol Cell 2022; 82:1616-1630. [PMID: 35477004 DOI: 10.1016/j.molcel.2022.04.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 02/02/2022] [Accepted: 04/04/2022] [Indexed: 12/16/2022]
Abstract
SMC protein complexes are molecular machines that provide structure to chromosomes. These complexes bridge DNA elements and by doing so build DNA loops in cis and hold together the sister chromatids in trans. We discuss how drastic conformational changes allow SMC complexes to build such intricate DNA structures. The tight regulation of these complexes controls fundamental chromosomal processes such as transcription, recombination, repair, and mitosis.
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38
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Yadav M, Jalan M, Srivastava M. Enhancer dependent repositioning of TCRb locus with respect to the chromosome territory. J Mol Biol 2022; 434:167509. [PMID: 35202629 DOI: 10.1016/j.jmb.2022.167509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 02/11/2022] [Accepted: 02/16/2022] [Indexed: 11/19/2022]
Abstract
Intranuclear position of several genes is dynamically altered during development concordant with their activation. To understand this dynamic, but non-random, nuclear organization, it is important to identify the relevant regulatory elements and trans acting factors. Murine TCRb locus gets activated during thymic development. Enhancer Eb is important for VDJ recombination at TCRb locus as it is critically required establishment of recombination center. Our analysis revealed that TCRb locus gets located out of the chromosome territory specifically in developing thymocytes. Further, CRISPR/Cas9 based deletion mutagenesis established an unambiguous role of enhancer Eb in defining TCRb location relative to chromosome territory. The ability to reposition the target locus relative to chromosome territory highlights a novel aspect pertaining to activity of enhancers which may contribute to their ability to regulate gene expression. Additionally, our observations have implications for understanding the role of enhancers in three-dimensional genome organization and function.
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Affiliation(s)
- Monika Yadav
- National Institute of Immunology, Aruna Asaf Ali Road, New Delhi 110067, India
| | - Manisha Jalan
- National Institute of Immunology, Aruna Asaf Ali Road, New Delhi 110067, India
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39
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Dauphars DJ, Mihai A, Wang L, Zhuang Y, Krangel MS. Trav15-dv6 family Tcrd rearrangements diversify the Tcra repertoire. J Exp Med 2022; 219:212913. [PMID: 34910107 PMCID: PMC8679779 DOI: 10.1084/jem.20211581] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 11/04/2021] [Accepted: 12/02/2021] [Indexed: 11/20/2022] Open
Abstract
The Tcra repertoire is generated by multiple rounds of Vα-Jα rearrangement. However, Tcrd recombination precedes Tcra recombination within the complex Tcra-Tcrd locus. Here, by ablating Tcrd recombination, we report that Tcrd rearrangement broadens primary Vα use to diversify the Tcra repertoire in mice. We reveal that use of Trav15-dv6 family V gene segments in Tcrd recombination imparts diversity in the Tcra repertoire by instigating use of central and distal Vα segments. Moreover, disruption of the regions containing these genes and their cis-regulatory elements identifies the Trav15-dv6 family as being responsible for driving central and distal Vα recombinations beyond their roles as substrates for Tcrd recombination. Our study demonstrates an indispensable role for Tcrd recombination in general, and the Trav15-dv6 family in particular, in the generation of a combinatorially diverse Tcra repertoire.
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Affiliation(s)
| | - Ariana Mihai
- Department of Immunology, Duke University Medical Center, Durham, NC
| | - Liuyang Wang
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC
| | - Yuan Zhuang
- Department of Immunology, Duke University Medical Center, Durham, NC
| | - Michael S Krangel
- Department of Immunology, Duke University Medical Center, Durham, NC
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40
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Libri A, Marton T, Deriano L. The (Lack of) DNA Double-Strand Break Repair Pathway Choice During V(D)J Recombination. Front Genet 2022; 12:823943. [PMID: 35082840 PMCID: PMC8785701 DOI: 10.3389/fgene.2021.823943] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 12/13/2021] [Indexed: 01/08/2023] Open
Abstract
DNA double-strand breaks (DSBs) are highly toxic lesions that can be mended via several DNA repair pathways. Multiple factors can influence the choice and the restrictiveness of repair towards a given pathway in order to warrant the maintenance of genome integrity. During V(D)J recombination, RAG-induced DSBs are (almost) exclusively repaired by the non-homologous end-joining (NHEJ) pathway for the benefit of antigen receptor gene diversity. Here, we review the various parameters that constrain repair of RAG-generated DSBs to NHEJ, including the peculiarity of DNA DSB ends generated by the RAG nuclease, the establishment and maintenance of a post-cleavage synaptic complex, and the protection of DNA ends against resection and (micro)homology-directed repair. In this physiological context, we highlight that certain DSBs have limited DNA repair pathway choice options.
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Affiliation(s)
- Alice Libri
- Genome Integrity, Immunity and Cancer Unit, Institut Pasteur, Université de Paris, INSERM U1223, Equipe Labellisée Ligue Contre Le Cancer, Paris, France
| | - Timea Marton
- Genome Integrity, Immunity and Cancer Unit, Institut Pasteur, Université de Paris, INSERM U1223, Equipe Labellisée Ligue Contre Le Cancer, Paris, France
| | - Ludovic Deriano
- Genome Integrity, Immunity and Cancer Unit, Institut Pasteur, Université de Paris, INSERM U1223, Equipe Labellisée Ligue Contre Le Cancer, Paris, France
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41
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Phipps J, Dubrana K. DNA Repair in Space and Time: Safeguarding the Genome with the Cohesin Complex. Genes (Basel) 2022; 13:198. [PMID: 35205243 PMCID: PMC8872453 DOI: 10.3390/genes13020198] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/20/2022] [Accepted: 01/20/2022] [Indexed: 12/04/2022] Open
Abstract
DNA double-strand breaks (DSBs) are a deleterious form of DNA damage, which must be robustly addressed to ensure genome stability. Defective repair can result in chromosome loss, point mutations, loss of heterozygosity or chromosomal rearrangements, which could lead to oncogenesis or cell death. We explore the requirements for the successful repair of DNA DSBs by non-homologous end joining and homology-directed repair (HDR) mechanisms in relation to genome folding and dynamics. On the occurrence of a DSB, local and global chromatin composition and dynamics, as well as 3D genome organization and break localization within the nuclear space, influence how repair proceeds. The cohesin complex is increasingly implicated as a key regulator of the genome, influencing chromatin composition and dynamics, and crucially genome organization through folding chromosomes by an active loop extrusion mechanism, and maintaining sister chromatid cohesion. Here, we consider how this complex is now emerging as a key player in the DNA damage response, influencing repair pathway choice and efficiency.
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Affiliation(s)
| | - Karine Dubrana
- UMR Stabilité Génétique Cellules Souches et Radiations, INSERM, iRCM/IBFJ CEA, Université de Paris and Université Paris-Saclay, F-92265 Fontenay-aux-Roses, France;
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42
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Glynn RA, Bassing CH. Nemo-Dependent, ATM-Mediated Signals from RAG DNA Breaks at Igk Feedback Inhibit V κ Recombination to Enforce Igκ Allelic Exclusion. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:371-383. [PMID: 34965965 PMCID: PMC8756740 DOI: 10.4049/jimmunol.2100696] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 11/01/2021] [Indexed: 01/17/2023]
Abstract
Monoallelic AgR gene expression underlies specific adaptive immune responses. AgR allelic exclusion is achieved by sequential initiation of V(D)J recombination between alleles and resultant protein from one allele signaling to prevent recombination of the other. The ATM kinase, a regulator of the DNA double-strand break (DSB) response, helps enforce allelic exclusion through undetermined mechanisms. ATM promotes repair of RAG1/RAG2 (RAG) endonuclease-induced DSBs and transduces signals from RAG DSBs during Igk gene rearrangement on one allele to transiently inhibit RAG1 protein expression, Igk accessibility, and RAG cleavage of the other allele. Yet, the relative contributions of ATM functions in DSB repair versus signaling to enforce AgR allelic exclusion remain undetermined. In this study, we demonstrate that inactivation in mouse pre-B cells of the NF-κB essential modulator (Nemo) protein, an effector of ATM signaling, diminishes RAG DSB-triggered repression of Rag1/Rag2 transcription and Igk accessibility but does not result in aberrant repair of RAG DSBs like ATM inactivation. We show that Nemo deficiency increases simultaneous biallelic Igk cleavage in pre-B cells and raises the frequency of B cells expressing Igκ proteins from both alleles. In contrast, the incidence of biallelic Igκ expression is not elevated by inactivation of the SpiC transcriptional repressor, which is induced by RAG DSBs in an ATM-dependent manner and suppresses Igk accessibility. Thus, we conclude that Nemo-dependent, ATM-mediated DNA damage signals enforce Igκ allelic exclusion by orchestrating transient repression of RAG expression and feedback inhibition of additional Igk rearrangements in response to RAG cleavage on one Igk allele.
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Affiliation(s)
- Rebecca A. Glynn
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104,Department of Pathology and Laboratory Medicine, Children’s Hospital of Pennsylvania, Philadelphia, PA 19104
| | - Craig H. Bassing
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104,Department of Pathology and Laboratory Medicine, Children’s Hospital of Pennsylvania, Philadelphia, PA 19104,Corresponding Author: Craig H. Bassing, Ph.D., Children’s Hospital of Philadelphia, 4054 Colket Translational Research Building, 3501 Civic Center Blvd., Philadelphia, PA 19104, 267-426-0311,
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43
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Lue JK, Downs-Canner S, Chaudhuri J. The role of B cells in the development, progression, and treatment of lymphomas and solid tumors. Adv Immunol 2022; 154:71-117. [PMID: 36038195 DOI: 10.1016/bs.ai.2022.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
B cells are integral components of the mammalian immune response as they have the ability to generate antibodies against an almost infinite array of antigens. Over the past several decades, significant scientific progress has been made in understanding that this enormous B cell diversity contributes to pathogen clearance. However, our understanding of the humoral response to solid tumors and to tumor-specific antigens is unclear. In this review, we first discuss how B cells interact with other cells in the tumor microenvironment and influence the development and progression of various solid tumors. The ability of B lymphocytes to generate antibodies against a diverse repertoire of antigens and subsequently tailor the humoral immune response to specific pathogens relies on their ability to undergo genomic alterations during their development and differentiation. We will discuss key transforming events that lead to the development of B cell lymphomas. Overall, this review provides a foundation for innovative therapeutic interventions for both lymphoma and solid tumor malignancies.
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Affiliation(s)
- Jennifer K Lue
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY, United States.
| | - Stephanie Downs-Canner
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY, United States.
| | - Jayanta Chaudhuri
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY, United States.
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44
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Hagman JR, Arends T, Laborda C, Knapp JR, Harmacek L, O'Connor BP. Chromodomain helicase DNA-binding 4 (CHD4) regulates early B cell identity and V(D)J recombination. Immunol Rev 2021; 305:29-42. [PMID: 34927255 DOI: 10.1111/imr.13054] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/22/2021] [Accepted: 12/02/2021] [Indexed: 12/20/2022]
Abstract
B lymphocytes develop from uncommitted precursors into immunoglobulin (antibody)-producing B cells, a major arm of adaptive immunity. Progression of early progenitors to antibody-expressing cells in the bone marrow is orchestrated by the temporal regulation of different gene programs at discrete developmental stages. A major question concerns how B cells control the accessibility of these genes to transcription factors. Research has implicated nucleosome remodeling ATPases as mediators of chromatin accessibility. Here, we describe studies of chromodomain helicase DNA-binding 4 (CHD4; also known as Mi-2β) in early B cell development. CHD4 comprises multiple domains that function in nucleosome mobilization and histone binding. CHD4 is a key component of Nucleosome Remodeling and Deacetylase, or NuRD (Mi-2) complexes, which assemble with other proteins that mediate transcriptional repression. We review data demonstrating that CHD4 is necessary for B lineage identity: early B lineage progression, proliferation in response to interleukin-7, responses to DNA damage, and cell survival in vivo. CHD4-NuRD is also required for the Ig heavy-chain repertoire by promoting utilization of distal variable (VH ) gene segments in V(D)J recombination. In conclusion, the regulation of chromatin accessibility by CHD4 is essential for production of antibodies by B cells, which in turn mediate humoral immune responses to pathogens and disease.
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Affiliation(s)
- James R Hagman
- Department of Immunology and Genomic Medicine, National Jewish Health, Denver, Colorado, USA.,Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.,Program in Molecular Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Tessa Arends
- Program in Molecular Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Curtis Laborda
- Center for Genes, Environment, and Health, National Jewish Health, Denver, Colorado, USA
| | - Jennifer R Knapp
- Center for Genes, Environment, and Health, National Jewish Health, Denver, Colorado, USA
| | - Laura Harmacek
- Center for Genes, Environment, and Health, National Jewish Health, Denver, Colorado, USA
| | - Brian P O'Connor
- Department of Immunology and Genomic Medicine, National Jewish Health, Denver, Colorado, USA.,Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.,Center for Genes, Environment, and Health, National Jewish Health, Denver, Colorado, USA
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45
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Sebastian R, Aladjem MI, Oberdoerffer P. Encounters in Three Dimensions: How Nuclear Topology Shapes Genome Integrity. Front Genet 2021; 12:746380. [PMID: 34745220 PMCID: PMC8566435 DOI: 10.3389/fgene.2021.746380] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 10/08/2021] [Indexed: 11/13/2022] Open
Abstract
Almost 25 years ago, the phosphorylation of a chromatin component, histone H2AX, was discovered as an integral part of the DNA damage response in eukaryotes. Much has been learned since then about the control of DNA repair in the context of chromatin. Recent technical and computational advances in imaging, biophysics and deep sequencing have led to unprecedented insight into nuclear organization, highlighting the impact of three-dimensional (3D) chromatin structure and nuclear topology on DNA repair. In this review, we will describe how DNA repair processes have adjusted to and in many cases adopted these organizational features to ensure accurate lesion repair. We focus on new findings that highlight the importance of chromatin context, topologically associated domains, phase separation and DNA break mobility for the establishment of repair-conducive nuclear environments. Finally, we address the consequences of aberrant 3D genome maintenance for genome instability and disease.
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Affiliation(s)
- Robin Sebastian
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, United States
| | - Mirit I Aladjem
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, United States
| | - Philipp Oberdoerffer
- Division of Cancer Biology, National Cancer Institute, NIH, Rockville, MD, United States
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46
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Piazza A, Bordelet H, Dumont A, Thierry A, Savocco J, Girard F, Koszul R. Cohesin regulates homology search during recombinational DNA repair. Nat Cell Biol 2021; 23:1176-1186. [PMID: 34750581 DOI: 10.1038/s41556-021-00783-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 09/27/2021] [Indexed: 02/06/2023]
Abstract
Homologous recombination repairs DNA double-strand breaks (DSB) using an intact dsDNA molecule as a template. It entails a homology search step, carried out along a conserved RecA/Rad51-ssDNA filament assembled on each DSB end. Whether, how and to what extent a DSB impacts chromatin folding, and how this (re)organization in turns influences the homology search process, remain ill-defined. Here we characterize two layers of spatial chromatin reorganization following DSB formation in Saccharomyces cerevisiae. Although cohesin folds chromosomes into cohesive arrays of ~20-kb-long chromatin loops as cells arrest in G2/M, the DSB-flanking regions interact locally in a resection- and 9-1-1 clamp-dependent manner, independently of cohesin, Mec1ATR, Rad52 and Rad51. This local structure blocks cohesin progression, constraining the DSB region at the base of a loop. Functionally, cohesin promotes DSB-dsDNA interactions and donor identification in cis, while inhibiting them in trans. This study identifies multiple direct and indirect ways by which cohesin regulates homology search during recombinational DNA repair.
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Affiliation(s)
- Aurèle Piazza
- Institut Pasteur, CNRS UMR3525, Unité Régulation Spatiale des Génomes, F-75015, Paris, France.
- Université de Lyon, ENS de Lyon, Université Claude Bernard, Laboratoire de Biologie et Modélisation de la Cellule, CNRS UMR5239, INSERM U1210, 46 allée d'Italie, 69007, Lyon, France.
| | - Hélène Bordelet
- Institut Pasteur, CNRS UMR3525, Unité Régulation Spatiale des Génomes, F-75015, Paris, France
- Université de Lyon, ENS de Lyon, Université Claude Bernard, Laboratoire de Biologie et Modélisation de la Cellule, CNRS UMR5239, INSERM U1210, 46 allée d'Italie, 69007, Lyon, France
| | - Agnès Dumont
- Université de Lyon, ENS de Lyon, Université Claude Bernard, Laboratoire de Biologie et Modélisation de la Cellule, CNRS UMR5239, INSERM U1210, 46 allée d'Italie, 69007, Lyon, France
| | - Agnès Thierry
- Institut Pasteur, CNRS UMR3525, Unité Régulation Spatiale des Génomes, F-75015, Paris, France
| | - Jérôme Savocco
- Université de Lyon, ENS de Lyon, Université Claude Bernard, Laboratoire de Biologie et Modélisation de la Cellule, CNRS UMR5239, INSERM U1210, 46 allée d'Italie, 69007, Lyon, France
| | - Fabien Girard
- Institut Pasteur, CNRS UMR3525, Unité Régulation Spatiale des Génomes, F-75015, Paris, France
| | - Romain Koszul
- Institut Pasteur, CNRS UMR3525, Unité Régulation Spatiale des Génomes, F-75015, Paris, France.
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47
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Frock RL, Sadeghi C, Meng J, Wang JL. DNA End Joining: G0-ing to the Core. Biomolecules 2021; 11:biom11101487. [PMID: 34680120 PMCID: PMC8533500 DOI: 10.3390/biom11101487] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 12/28/2022] Open
Abstract
Humans have evolved a series of DNA double-strand break (DSB) repair pathways to efficiently and accurately rejoin nascently formed pairs of double-stranded DNA ends (DSEs). In G0/G1-phase cells, non-homologous end joining (NHEJ) and alternative end joining (A-EJ) operate to support covalent rejoining of DSEs. While NHEJ is predominantly utilized and collaborates extensively with the DNA damage response (DDR) to support pairing of DSEs, much less is known about A-EJ collaboration with DDR factors when NHEJ is absent. Non-cycling lymphocyte progenitor cells use NHEJ to complete V(D)J recombination of antigen receptor genes, initiated by the RAG1/2 endonuclease which holds its pair of targeted DSBs in a synapse until each specified pair of DSEs is handed off to the NHEJ DSB sensor complex, Ku. Similar to designer endonuclease DSBs, the absence of Ku allows for A-EJ to access RAG1/2 DSEs but with random pairing to complete their repair. Here, we describe recent insights into the major phases of DSB end joining, with an emphasis on synapsis and tethering mechanisms, and bring together new and old concepts of NHEJ vs. A-EJ and on RAG2-mediated repair pathway choice.
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48
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Beilinson HA, Glynn RA, Yadavalli AD, Xiao J, Corbett E, Saribasak H, Arya R, Miot C, Bhattacharyya A, Jones JM, Pongubala JM, Bassing CH, Schatz DG. The RAG1 N-terminal region regulates the efficiency and pathways of synapsis for V(D)J recombination. J Exp Med 2021; 218:e20210250. [PMID: 34402853 PMCID: PMC8374863 DOI: 10.1084/jem.20210250] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 06/30/2021] [Accepted: 07/30/2021] [Indexed: 11/29/2022] Open
Abstract
Immunoglobulin and T cell receptor gene assembly depends on V(D)J recombination initiated by the RAG1-RAG2 recombinase. The RAG1 N-terminal region (NTR; aa 1-383) has been implicated in regulatory functions whose influence on V(D)J recombination and lymphocyte development in vivo is poorly understood. We generated mice in which RAG1 lacks ubiquitin ligase activity (P326G), the major site of autoubiquitination (K233R), or its first 215 residues (Δ215). While few abnormalities were detected in R1.K233R mice, R1.P326G mice exhibit multiple features indicative of reduced recombination efficiency, including an increased Igκ+:Igλ+ B cell ratio and decreased recombination of Igh, Igκ, Igλ, and Tcrb loci. Previous studies indicate that synapsis of recombining partners during Igh recombination occurs through two pathways: long-range scanning and short-range collision. We find that R1Δ215 mice exhibit reduced short-range Igh and Tcrb D-to-J recombination. Our findings indicate that the RAG1 NTR regulates V(D)J recombination and lymphocyte development by multiple pathways, including control of the balance between short- and long-range recombination.
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Affiliation(s)
- Helen A. Beilinson
- Department of Immunobiology, Yale School of Medicine, Yale University, New Haven, CT
| | - Rebecca A. Glynn
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Anurupa Devi Yadavalli
- Department of Immunobiology, Yale School of Medicine, Yale University, New Haven, CT
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Jianxiong Xiao
- Department of Immunobiology, Yale School of Medicine, Yale University, New Haven, CT
| | - Elizabeth Corbett
- Department of Immunobiology, Yale School of Medicine, Yale University, New Haven, CT
| | - Huseyin Saribasak
- Department of Immunobiology, Yale School of Medicine, Yale University, New Haven, CT
| | - Rahul Arya
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Charline Miot
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Anamika Bhattacharyya
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, DC
| | - Jessica M. Jones
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, DC
| | - Jagan M.R. Pongubala
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Craig H. Bassing
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - David G. Schatz
- Department of Immunobiology, Yale School of Medicine, Yale University, New Haven, CT
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
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49
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Savocco J, Piazza A. Recombination-mediated genome rearrangements. Curr Opin Genet Dev 2021; 71:63-71. [PMID: 34325160 DOI: 10.1016/j.gde.2021.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 06/20/2021] [Accepted: 06/29/2021] [Indexed: 12/14/2022]
Abstract
Homologous recombination (HR) is a universal DNA double-strand break (DSB) repair pathway that uses an intact DNA molecule as a template. Signature HR reactions are homology search and DNA strand invasion catalyzed by the prototypical RecA-ssDNA filament (Rad51 and Dmc1 in eukaryotes), which produces heteroduplex DNA-containing joint molecules (JMs). These reactions uniquely infringe on the DNA strands association established at replication, on the basis of substantial sequence similarity. For that reason, and despite the high fidelity of its templated nature, DSB repair by HR authorizes the alteration of genome structure, guided by repetitive DNA elements. The resulting structural variations (SVs) can involve vast genomic regions, potentially affecting multiple coding sequences and regulatory elements at once, with possible pathological consequences. Here, we discuss recent advances in our understanding of genetic and molecular vulnerabilities of HR leading to SVs, and of the various fidelity-enforcing factors acting across scales on the balancing act of this complex pathway. An emphasis is put on extra-chomosomal DNAs, both product of, and substrate for HR-mediated chromosomal rearrangements.
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Affiliation(s)
- Jérôme Savocco
- Université de Lyon, ENS de Lyon, Université Claude Bernard, CNRS UMR5239, Laboratoire de Biologie et Modélisation de la Cellule, Lyon, France
| | - Aurèle Piazza
- Université de Lyon, ENS de Lyon, Université Claude Bernard, CNRS UMR5239, Laboratoire de Biologie et Modélisation de la Cellule, Lyon, France.
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50
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Davidson IF, Peters JM. Genome folding through loop extrusion by SMC complexes. Nat Rev Mol Cell Biol 2021; 22:445-464. [PMID: 33767413 DOI: 10.1038/s41580-021-00349-7] [Citation(s) in RCA: 218] [Impact Index Per Article: 72.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/03/2021] [Indexed: 02/02/2023]
Abstract
Genomic DNA is folded into loops and topologically associating domains (TADs), which serve important structural and regulatory roles. It has been proposed that these genomic structures are formed by a loop extrusion process, which is mediated by structural maintenance of chromosomes (SMC) protein complexes. Recent single-molecule studies have shown that the SMC complexes condensin and cohesin are indeed able to extrude DNA into loops. In this Review, we discuss how the loop extrusion hypothesis can explain key features of genome architecture; cellular functions of loop extrusion, such as separation of replicated DNA molecules, facilitation of enhancer-promoter interactions and immunoglobulin gene recombination; and what is known about the mechanism of loop extrusion and its regulation, for example, by chromatin boundaries that depend on the DNA binding protein CTCF. We also discuss how the loop extrusion hypothesis has led to a paradigm shift in our understanding of both genome architecture and the functions of SMC complexes.
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Affiliation(s)
- Iain F Davidson
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria.
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