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Matos-Rodrigues G, Hisey JA, Nussenzweig A, Mirkin SM. Detection of alternative DNA structures and its implications for human disease. Mol Cell 2023; 83:3622-3641. [PMID: 37863029 DOI: 10.1016/j.molcel.2023.08.018] [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: 06/19/2023] [Revised: 08/01/2023] [Accepted: 08/16/2023] [Indexed: 10/22/2023]
Abstract
Around 3% of the genome consists of simple DNA repeats that are prone to forming alternative (non-B) DNA structures, such as hairpins, cruciforms, triplexes (H-DNA), four-stranded guanine quadruplexes (G4-DNA), and others, as well as composite RNA:DNA structures (e.g., R-loops, G-loops, and H-loops). These DNA structures are dynamic and favored by the unwinding of duplex DNA. For many years, the association of alternative DNA structures with genome function was limited by the lack of methods to detect them in vivo. Here, we review the recent advancements in the field and present state-of-the-art technologies and methods to study alternative DNA structures. We discuss the limitations of these methods as well as how they are beginning to provide insights into causal relationships between alternative DNA structures, genome function and stability, and human disease.
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Affiliation(s)
| | - Julia A Hisey
- Department of Biology, Tufts University, Medford, MA, USA
| | - André Nussenzweig
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA.
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2
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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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Worth AN, Palmer VL, Schabla NM, Perry GA, Fraser-Philbin AN, Swanson PC. Receptor editing constrains development of phosphatidyl choline-specific B cells in V H12-transgenic mice. Cell Rep 2022; 39:110899. [PMID: 35705027 DOI: 10.1016/j.celrep.2022.110899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 03/22/2022] [Accepted: 05/10/2022] [Indexed: 11/03/2022] Open
Abstract
B1 B cells reactive to phosphatidyl choline (PtC) exhibit restricted immunoglobulin heavy chain (HC) and light chain (LC) combinations, exemplified by VH12/Vκ4/5H. Two checkpoints are thought to focus PtC+ B cell maturation in VH12-transgenic mice (VH12 mice): V-J rearrangements encoding a "permissive" LC capable of VH12 HC pairing are selected first, followed by positive selection based on PtC binding, often requiring LC receptor editing to salvage PtC- B cells and acquire PtC reactivity. However, evidence obtained from breeding VH12 mice to editing-defective dnRAG1 mice and analyzing LC sequences from PtC+ and PtC- B cell subsets instead suggests that receptor editing functions after initial positive selection to remove PtC+ B cells in VH12 mice. This offers a mechanism to constrain natural, polyreactive B cells to limit their frequency. Sequencing also reveals occasional in-frame hybrid LC genes, reminiscent of type 2 gene replacement, that, testing suggests, arise via a recombination-activating gene (RAG)-independent mechanism.
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Affiliation(s)
- Alexandra N Worth
- Department of Medical Microbiology and Immunology, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA
| | - Victoria L Palmer
- Department of Medical Microbiology and Immunology, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA
| | - N Max Schabla
- Department of Medical Microbiology and Immunology, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA; Shoreline Biosciences, San Diego, CA 92121, USA
| | - Greg A Perry
- Department of Medical Microbiology and Immunology, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA
| | - Anna N Fraser-Philbin
- Department of Medical Microbiology and Immunology, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA
| | - Patrick C Swanson
- Department of Medical Microbiology and Immunology, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA.
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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: 1] [Impact Index Per Article: 0.5] [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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The dystonia gene THAP1 controls DNA double-strand break repair choice. Mol Cell 2021; 81:2611-2624.e10. [PMID: 33857404 DOI: 10.1016/j.molcel.2021.03.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 02/01/2021] [Accepted: 03/19/2021] [Indexed: 12/26/2022]
Abstract
The Shieldin complex shields double-strand DNA breaks (DSBs) from nucleolytic resection. Curiously, the penultimate Shieldin component, SHLD1, is one of the least abundant mammalian proteins. Here, we report that the transcription factors THAP1, YY1, and HCF1 bind directly to the SHLD1 promoter, where they cooperatively maintain the low basal expression of SHLD1, thereby ensuring a proper balance between end protection and resection during DSB repair. The loss of THAP1-dependent SHLD1 expression confers cross-resistance to poly (ADP-ribose) polymerase (PARP) inhibitor and cisplatin in BRCA1-deficient cells and shorter progression-free survival in ovarian cancer patients. Moreover, the embryonic lethality and PARPi sensitivity of BRCA1-deficient mice is rescued by ablation of SHLD1. Our study uncovers a transcriptional network that directly controls DSB repair choice and suggests a potential link between DNA damage and pathogenic THAP1 mutations, found in patients with the neurodevelopmental movement disorder adult-onset torsion dystonia type 6.
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Oster S, Aqeilan RI. Programmed DNA Damage and Physiological DSBs: Mapping, Biological Significance and Perturbations in Disease States. Cells 2020; 9:cells9081870. [PMID: 32785139 PMCID: PMC7463922 DOI: 10.3390/cells9081870] [Citation(s) in RCA: 5] [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: 07/13/2020] [Revised: 08/02/2020] [Accepted: 08/05/2020] [Indexed: 12/12/2022] Open
Abstract
DNA double strand breaks (DSBs) are known to be the most toxic and threatening of the various types of breaks that may occur to the DNA. However, growing evidence continuously sheds light on the regulatory roles of programmed DSBs. Emerging studies demonstrate the roles of DSBs in processes such as T and B cell development, meiosis, transcription and replication. A significant recent progress in the last few years has contributed to our advanced knowledge regarding the functions of DSBs is the development of many next generation sequencing (NGS) methods, which have considerably advanced our capabilities. Other studies have focused on the implications of programmed DSBs on chromosomal aberrations and tumorigenesis. This review aims to summarize what is known about DNA damage in its physiological context. In addition, we will examine the advancements of the past several years, which have made an impact on the study of genome landscape and its organization.
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Affiliation(s)
- Sara Oster
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem 9112001, Israel;
| | - Rami I. Aqeilan
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem 9112001, Israel;
- Department of Cancer Biology and Genetics, Wexner Medical Center, The Ohio State University, Columbus, OH 43210, USA
- Correspondence:
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Allyn BM, Lee KD, Bassing CH. Genome Topology Control of Antigen Receptor Gene Assembly. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2020; 204:2617-2626. [PMID: 32366683 PMCID: PMC7440635 DOI: 10.4049/jimmunol.1901356] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 02/22/2020] [Indexed: 02/02/2023]
Abstract
The past decade has increased our understanding of how genome topology controls RAG endonuclease-mediated assembly of lymphocyte AgR genes. New technologies have illuminated how the large IgH, Igκ, TCRα/δ, and TCRβ loci fold into compact structures that place their numerous V gene segments in similar three-dimensional proximity to their distal recombination center composed of RAG-bound (D)J gene segments. Many studies have shown that CTCF and cohesin protein-mediated chromosome looping have fundamental roles in lymphocyte lineage- and developmental stage-specific locus compaction as well as broad usage of V segments. CTCF/cohesin-dependent loops have also been shown to direct and restrict RAG activity within chromosome domains. We summarize recent work in elucidating molecular mechanisms that govern three-dimensional chromosome organization and in investigating how these dynamic mechanisms control V(D)J recombination. We also introduce remaining questions for how CTCF/cohesin-dependent and -independent genome architectural mechanisms might regulate compaction and recombination of AgR loci.
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Affiliation(s)
- Brittney M Allyn
- Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; and
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Kyutae D Lee
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Craig H Bassing
- Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; and
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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