1
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Yin Y, Guo Y, Jiang Y, Quinlan B, Peng H, Crynen G, He W, Zhang L, Ou T, Bailey CC, Farzan M. In vivo affinity maturation of mouse B cells reprogrammed to express human antibodies. Nat Biomed Eng 2024; 8:361-379. [PMID: 38486104 DOI: 10.1038/s41551-024-01179-6] [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: 02/07/2023] [Accepted: 02/02/2024] [Indexed: 03/21/2024]
Abstract
Mice adoptively transferred with mouse B cells edited via CRISPR to express human antibody variable chains could help evaluate candidate vaccines and develop better antibody therapies. However, current editing strategies disrupt the heavy-chain locus, resulting in inefficient somatic hypermutation without functional affinity maturation. Here we show that these key B-cell functions can be preserved by directly and simultaneously replacing recombined mouse heavy and kappa chains with those of human antibodies, using a single Cas12a-mediated cut at each locus and 5' homology arms complementary to distal V segments. Cells edited in this way to express the human immunodeficiency virus type 1 (HIV-1) broadly neutralizing antibody 10-1074 or VRC26.25-y robustly hypermutated and generated potent neutralizing plasma in vaccinated mice. The 10-1074 variants isolated from the mice neutralized a global panel of HIV-1 isolates more efficiently than wild-type 10-1074 while maintaining its low polyreactivity and long half-life. We also used the approach to improve the potency of anti-SARS-CoV-2 antibodies against recent Omicron strains. In vivo affinity maturation of B cells edited at their native loci may facilitate the development of broad, potent and bioavailable antibodies.
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Affiliation(s)
- Yiming Yin
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
- The Center for Integrated Solutions to Infectious Diseases (CISID), The Broad Institute of MIT and Harvard, Cambridge, MA, USA.
| | - Yan Guo
- Department of Immunology and Microbiology, Scripps Biomedical Research, University of Florida, Jupiter, FL, USA
| | - Yuxuan Jiang
- Institute of Biomechanics and Medical Engineering, AML, Department of Engineering Mechanics, Tsinghua University, Beijing, People's Republic of China
| | - Brian Quinlan
- Department of Immunology and Microbiology, Scripps Biomedical Research, University of Florida, Jupiter, FL, USA
| | - Haiyong Peng
- Department of Immunology and Microbiology, Scripps Biomedical Research, University of Florida, Jupiter, FL, USA
| | - Gogce Crynen
- Department of Immunology and Microbiology, Scripps Biomedical Research, University of Florida, Jupiter, FL, USA
| | - Wenhui He
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- The Center for Integrated Solutions to Infectious Diseases (CISID), The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Lizhou Zhang
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Tianling Ou
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- The Center for Integrated Solutions to Infectious Diseases (CISID), The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Charles C Bailey
- The Center for Integrated Solutions to Infectious Diseases (CISID), The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Michael Farzan
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- The Center for Integrated Solutions to Infectious Diseases (CISID), The Broad Institute of MIT and Harvard, Cambridge, MA, USA
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2
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Dai S, Guo L, Dey R, Guo M, Zhang X, Bates D, Cayford J, Jiang L, Wei H, Chen Z, Zhang Y, Chen L, Chen Y. Structural insights into the HDAC4-MEF2A-DNA complex and its implication in long-range transcriptional regulation. Nucleic Acids Res 2024; 52:2711-2723. [PMID: 38281192 PMCID: PMC10954479 DOI: 10.1093/nar/gkae036] [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: 07/27/2023] [Revised: 12/01/2023] [Accepted: 01/10/2024] [Indexed: 01/30/2024] Open
Abstract
Class IIa Histone deacetylases (HDACs), including HDAC4, 5, 7 and 9, play key roles in multiple important developmental and differentiation processes. Recent studies have shown that class IIa HDACs exert their transcriptional repressive function by interacting with tissue-specific transcription factors, such as members of the myocyte enhancer factor 2 (MEF2) family of transcription factors. However, the molecular mechanism is not well understood. In this study, we determined the crystal structure of an HDAC4-MEF2A-DNA complex. This complex adopts a dumbbell-shaped overall architecture, with a 2:4:2 stoichiometry of HDAC4, MEF2A and DNA molecules. In the complex, two HDAC4 molecules form a dimer through the interaction of their glutamine-rich domain (GRD) to form the stem of the 'dumbbell'; while two MEF2A dimers and their cognate DNA molecules are bridged by the HDAC4 dimer. Our structural observations were then validated using biochemical and mutagenesis assays. Further cell-based luciferase reporter gene assays revealed that the dimerization of HDAC4 is crucial in its ability to repress the transcriptional activities of MEF2 proteins. Taken together, our findings not only provide the structural basis for the assembly of the HDAC4-MEF2A-DNA complex but also shed light on the molecular mechanism of HDAC4-mediated long-range gene regulation.
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Affiliation(s)
- Shuyan Dai
- Department of Oncology, NHC Key Laboratory of Cancer Proteomics & State Local Joint Engineering Laboratory for Anticancer Drugs, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Department of Pharmacology, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha 410078, China
| | - Liang Guo
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0215, USA
| | - Raja Dey
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Ming Guo
- Department of Oncology, NHC Key Laboratory of Cancer Proteomics & State Local Joint Engineering Laboratory for Anticancer Drugs, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Xiangqian Zhang
- Department of Oncology, NHC Key Laboratory of Cancer Proteomics & State Local Joint Engineering Laboratory for Anticancer Drugs, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Darren Bates
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0215, USA
| | - Justin Cayford
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Longying Jiang
- Department of Oncology, NHC Key Laboratory of Cancer Proteomics & State Local Joint Engineering Laboratory for Anticancer Drugs, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Hudie Wei
- Department of Oncology, NHC Key Laboratory of Cancer Proteomics & State Local Joint Engineering Laboratory for Anticancer Drugs, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Zhuchu Chen
- Department of Oncology, NHC Key Laboratory of Cancer Proteomics & State Local Joint Engineering Laboratory for Anticancer Drugs, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Ye Zhang
- Department of Oncology, NHC Key Laboratory of Cancer Proteomics & State Local Joint Engineering Laboratory for Anticancer Drugs, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Lin Chen
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Yongheng Chen
- Department of Oncology, NHC Key Laboratory of Cancer Proteomics & State Local Joint Engineering Laboratory for Anticancer Drugs, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
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3
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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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4
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Hung TC, Kingsley DM, Boettiger AN. Boundary stacking interactions enable cross-TAD enhancer-promoter communication during limb development. Nat Genet 2024; 56:306-314. [PMID: 38238628 DOI: 10.1038/s41588-023-01641-2] [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: 02/06/2023] [Accepted: 12/06/2023] [Indexed: 02/15/2024]
Abstract
Although promoters and their enhancers are frequently contained within a topologically associating domain (TAD), some developmentally important genes have their promoter and enhancers within different TADs. Hypotheses about molecular mechanisms enabling cross-TAD interactions remain to be assessed. To test these hypotheses, we used optical reconstruction of chromatin architecture to characterize the conformations of the Pitx1 locus on single chromosomes in developing mouse limbs. Our data support a model in which neighboring boundaries are stacked as a result of loop extrusion, bringing boundary-proximal cis-elements into contact. This stacking interaction also contributes to the appearance of architectural stripes in the population average maps. Through molecular dynamics simulations, we found that increasing boundary strengths facilitates the formation of the stacked boundary conformation, counter-intuitively facilitating border bypass. This work provides a revised view of the TAD borders' function, both facilitating and preventing cis-regulatory interactions, and introduces a framework to distinguish border-crossing from border-respecting enhancer-promoter pairs.
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Affiliation(s)
- Tzu-Chiao Hung
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - David M Kingsley
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Alistair N Boettiger
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, USA.
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5
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Yin Y, Guo Y, Jiang Y, Quinlan B, Peng H, Crynen G, He W, Zhang L, Ou T, Bailey CC, Farzan M. In vivo affinity maturation of murine B cells reprogrammed to express human antibodies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.20.563154. [PMID: 37961481 PMCID: PMC10634681 DOI: 10.1101/2023.10.20.563154] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
CRISPR-edited murine B cells engineered to express human antibody variable chains proliferate, class switch, and secrete these antibodies in vaccinated mice. However, current strategies disrupt the heavy-chain locus, resulting in inefficient somatic hypermutation without functional affinity maturation. Here we show that recombined murine heavy- and kappa-variable genes can be directly and simultaneously overwritten, using Cas12a-mediated cuts at their 3'-most J segments and 5' homology arms complementary to distal V segments. Cells edited in this way to express the HIV-1 broadly neutralizing antibodies 10-1074 or VRC26.25-y robustly hypermutated and generated potent neutralizing plasma in vaccinated recipient mice. 10-1074 variants isolated from these mice bound and neutralized HIV-1 envelope glycoprotein more efficiently than wild-type 10-1074 while maintaining or improving its already low polyreactivity and long in vivo half-life. We further validated this approach by generating substantially broader and more potent variants of the anti-SARS-CoV-2 antibodies ZCB11 and S309. Thus, B cells edited at their native loci affinity mature, facilitating development of broad, potent, and bioavailable antibodies and expanding the potential applications of engineered B cells.
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Affiliation(s)
- Yiming Yin
- Department of Pediatrics, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115
- The Center for Integrated Solutions to Infectious Diseases (CISID), The Broad Institute of MIT and Harvard, Cambridge, MA 02142
| | - Yan Guo
- Department of Immunology and Microbiology, Scripps Biomedical Research, University of Florida; Jupiter, FL 33458
| | - Yuxuan Jiang
- Institute of Biomechanics and Medical Engineering, AML, Department of Engineering Mechanics, Tsinghua University; Beijing 100084, PR China
| | - Brian Quinlan
- Department of Immunology and Microbiology, Scripps Biomedical Research, University of Florida; Jupiter, FL 33458
| | - Haiyong Peng
- Department of Immunology and Microbiology, Scripps Biomedical Research, University of Florida; Jupiter, FL 33458
| | - Gogce Crynen
- Department of Immunology and Microbiology, Scripps Biomedical Research, University of Florida; Jupiter, FL 33458
| | - Wenhui He
- Department of Pediatrics, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115
- The Center for Integrated Solutions to Infectious Diseases (CISID), The Broad Institute of MIT and Harvard, Cambridge, MA 02142
| | - Lizhou Zhang
- Department of Pediatrics, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115
| | - Tianling Ou
- Department of Pediatrics, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115
- The Center for Integrated Solutions to Infectious Diseases (CISID), The Broad Institute of MIT and Harvard, Cambridge, MA 02142
| | - Charles C. Bailey
- The Center for Integrated Solutions to Infectious Diseases (CISID), The Broad Institute of MIT and Harvard, Cambridge, MA 02142
| | - Michael Farzan
- Department of Pediatrics, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115
- The Center for Integrated Solutions to Infectious Diseases (CISID), The Broad Institute of MIT and Harvard, Cambridge, MA 02142
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6
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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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7
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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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8
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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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9
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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] [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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10
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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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11
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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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12
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Calcagno G, Ouzren N, Kaminski S, Ghislin S, Frippiat JP. Chronic Hypergravity Induces a Modification of Histone H3 Lysine 27 Trimethylation at TCRβ Locus in Murine Thymocytes. Int J Mol Sci 2022; 23:ijms23137133. [PMID: 35806138 PMCID: PMC9267123 DOI: 10.3390/ijms23137133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/24/2022] [Accepted: 06/25/2022] [Indexed: 11/16/2022] Open
Abstract
Gravity changes are major stressors encountered during spaceflight that affect the immune system. We previously evidenced that hypergravity exposure during gestation affects the TCRβ repertoire of newborn pups. To identify the mechanisms underlying this observation, we studied post-translational histone modifications. We first showed that among the four studied post-translational histone H3 modifications, only lysine 27 trimethylation (H3K27me3) is downregulated in the thymus of mice exposed to 2× g for 21 days. We then asked whether the TCRβ locus chromatin structure is altered by hypergravity exposure. ChIP studies performed on four Vβ segments of the murine double-negative SCIET27 thymic cell line, which corresponds to the last maturation stage before V(D)J recombination, revealed increases in H3K27me3 after 2× g exposure. Finally, we evaluated the implication for the EZH2 methyltransferase in the regulation of the H3K27me3 level at these Vβ segments by treating SCIET27 cells with the GSK126-specific inhibitor. These experiments showed that the downregulation of H3K27me3 contributes to the regulation of the Vβ germline transcript expression that precedes V(D)J recombination. These data show that modifications of H3K27me3 at the TCRβ locus likely contribute to an explanation of why the TCR repertoire is affected by gravity changes and imply, for the first time, EZH2 in the regulation of the TCRβ locus chromatin structure.
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13
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Bruzeau C, Cook-Moreau J, Pinaud E, Le Noir S. Contribution of Immunoglobulin Enhancers to B Cell Nuclear Organization. Front Immunol 2022; 13:877930. [PMID: 35812441 PMCID: PMC9263370 DOI: 10.3389/fimmu.2022.877930] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 05/26/2022] [Indexed: 11/19/2022] Open
Abstract
B cells undergo genetic rearrangements at immunoglobulin gene (Ig) loci during B cell maturation. First V(D)J recombination occurs during early B cell stages followed by class switch recombination (CSR) and somatic hypermutation (SHM) which occur during mature B cell stages. Given that RAG1/2 induces DNA double strand breaks (DSBs) during V(D)J recombination and AID (Activation-Induced Deaminase) leads to DNA modifications (mutations during SHM or DNA DSBs during CSR), it is mandatory that IgH rearrangements be tightly regulated to avoid any mutations or translocations within oncogenes. Ig loci contain various cis-regulatory elements that are involved in germline transcription, chromatin modifications or RAG/AID recruitment. Ig cis-regulatory elements are increasingly recognized as being involved in nuclear positioning, heterochromatin addressing and chromosome loop regulation. In this review, we examined multiple data showing the critical interest of studying Ig gene regulation at the whole nucleus scale. In this context, we highlighted the essential function of Ig gene regulatory elements that now have to be considered as nuclear organizers in B lymphocytes.
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14
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Aubrey M, Warburg ZJ, Murre C. Helix-Loop-Helix Proteins in Adaptive Immune Development. Front Immunol 2022; 13:881656. [PMID: 35634342 PMCID: PMC9134016 DOI: 10.3389/fimmu.2022.881656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 04/04/2022] [Indexed: 11/13/2022] Open
Abstract
The E/ID protein axis is instrumental for defining the developmental progression and functions of hematopoietic cells. The E proteins are dimeric transcription factors that activate gene expression programs and coordinate changes in chromatin organization. Id proteins are antagonists of E protein activity. Relative levels of E/Id proteins are modulated throughout hematopoietic development to enable the progression of hematopoietic stem cells into multiple adaptive and innate immune lineages including natural killer cells, B cells and T cells. In early progenitors, the E proteins promote commitment to the T and B cell lineages by orchestrating lineage specific programs of gene expression and regulating VDJ recombination of antigen receptor loci. In mature B cells, the E/Id protein axis functions to promote class switch recombination and somatic hypermutation. E protein activity further regulates differentiation into distinct CD4+ and CD8+ T cells subsets and instructs mature T cell immune responses. In this review, we discuss how the E/Id proteins define the adaptive immune system lineages, focusing on their role in directing developmental gene programs.
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Affiliation(s)
- Megan Aubrey
- Division of Biological Sciences, Section of Molecular Biology, University of California, San Diego, San Diego, CA, United States
| | - Zachary J Warburg
- Division of Biological Sciences, Section of Molecular Biology, University of California, San Diego, San Diego, CA, United States
| | - Cornelis Murre
- Division of Biological Sciences, Section of Molecular Biology, University of California, San Diego, San Diego, CA, United States
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15
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The Annotation of Zebrafish Enhancer Trap Lines Generated with PB Transposon. Curr Issues Mol Biol 2022; 44:2614-2621. [PMID: 35735619 PMCID: PMC9221761 DOI: 10.3390/cimb44060178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 11/16/2022] Open
Abstract
An enhancer trap (ET) mediated by a transposon is an effective method for functional gene research. Here, an ET system based on a PB transposon that carries a mini Krt4 promoter (the keratin4 minimal promoter from zebrafish) and the green fluorescent protein gene (GFP) has been used to produce zebrafish ET lines. One enhancer trap line with eye-specific expression GFP named EYE was used to identify the trapped enhancers and genes. Firstly, GFP showed a temporal and spatial expression pattern with whole-embryo expression at 6, 12, and 24 hpf stages and eye-specific expression from 2 to 7 dpf. Then, the genome insertion sites were detected by splinkerette PCR (spPCR). The Krt4-GFP was inserted into the fourth intron of the gene itgav (integrin, alpha V) in chromosome 9 of the zebrafish genome, with the GFP direction the same as that of the itgav gene. By the alignment of homologous gene sequences in different species, three predicted endogenous enhancers were obtained. The trapped endogenous gene itgav, whose overexpression is related to hepatocellular carcinoma, showed a similar expression pattern as GFP detected by in situ hybridization, which suggested that GFP and itgav were possibly regulated by the same enhancers. In short, the zebrafish enhancer trap lines generated by the PB transposon-mediated enhancer trap technology in this study were valuable resources as visual markers to study the regulators and genes. This work provides an efficient method to identify and isolate tissue-specific enhancer sequences.
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16
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Knoch TA. How Genomes Emerge, Function, and Evolve: Living Systems Emergence-Genotype-Phenotype-Multilism-Genome/Systems Ecology. Results Probl Cell Differ 2022; 70:103-156. [PMID: 36348106 DOI: 10.1007/978-3-031-06573-6_4] [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: 06/16/2023]
Abstract
What holds together the world in its innermost, what life is, how it emerges, functions, and evolves, has not only been an epic matter of endless romantic sunset poetry and philosophy, but also manifests explicitly in its perhaps most central organization unit-genomes. Their 3D architecture and dynamics, including the interaction networks of regulatory elements, obviously co-evolved as inseparable systems allowing the physical storage, expression, and replication of genetic information. Since we were able to fill finally the much-debated centennial gaps in their 3D architecture and dynamics, now entire new perspectives open beyond epigenetics reaching as far as a general understanding of living systems: besides the previously known DNA double helix and nucleosome structure, the latter compact into a chromatin quasi-fibre folded into stable loops forming stable multi-loop aggregates/rosettes connected by linkers, creating hence the again already known chromosome arms and entire chromosomes forming the cell nucleus. Instantly and for the first time this leads now to a consistent and cross-proven systems statistical mechanics genomics framework elucidating genome intrinsic function and regulation including various components. It balances stability/flexibility ensuring genome integrity, enabling expression/regulation of genetic information, as well as genome replication/spread. Furthermore, genotype and phenotype are multiplisticly entangled being evolutionarily the outcome of both Darwinian natural selection and Lamarckian self-referenced manipulation-all embedded in even broader genome ecology (autopoietic) i(!)n- and environmental scopes. This allows formulating new meta-level functional semantics of genomics, i.e. notions as communication of genes, genomes, and information networks, architectural and dynamic spaces for creativity and innovation, or genomes as central geno-/phenotype entanglements. Beyond and most fundamentally, the paradoxical-seeming local equilibrium substance stability in its entity though far from a universal heat-death-like equilibrium is solved, and system irreversibility, time directionality, and thus the emergence of existence are clarified. Consequently, real deep understandings of genomes, life, and complex systems in general appear in evolutionary perspectives as well as from systems analyses, via system damage/disease (its repair/cure and manipulation) as far as the understanding of extraterrestrial life, the de novo creation and thus artificial life, and even the raison d'etre.
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Affiliation(s)
- Tobias A Knoch
- Biophysical Genomics, TAKnoch Joined Operations Administrative Office, Mannheim, Germany.
- Human Ecology and Complex Systems, German Society for Human Ecology (DGH), TAKnoch Joined Operations Administrative Office, Mannheim, Germany.
- TAK Renewable Energy UG, TAKnoch Joined Operations Administrative Office, Mannheim, Germany.
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17
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Hausmann M, Hildenbrand G, Pilarczyk G. Networks and Islands of Genome Nano-architecture and Their Potential Relevance for Radiation Biology : (A Hypothesis and Experimental Verification Hints). Results Probl Cell Differ 2022; 70:3-34. [PMID: 36348103 DOI: 10.1007/978-3-031-06573-6_1] [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] [Indexed: 06/16/2023]
Abstract
The cell nucleus is a complex biological system in which simultaneous reactions and functions take place to keep the cell as an individualized, specialized system running well. The cell nucleus contains chromatin packed in various degrees of density and separated in volumes of chromosome territories and subchromosomal domains. Between the chromatin, however, there is enough "free" space for floating RNA, proteins, enzymes, ATPs, ions, water molecules, etc. which are trafficking by super- and supra-diffusion to the interaction points where they are required. It seems that this trafficking works somehow automatically and drives the system perfectly. After exposure to ionizing radiation causing DNA damage from single base damage up to chromatin double-strand breaks, the whole system "cell nucleus" responds, and repair processes are starting to recover the fully functional and intact system. In molecular biology, many individual epigenetic pathways of DNA damage response or repair of single and double-strand breaks are described. How these responses are embedded into the response of the system as a whole is often out of the focus of consideration. In this article, we want to follow the hypothesis of chromatin architecture's impact on epigenetic pathways and vice versa. Based on the assumption that chromatin acts like an "aperiodic solid state within a limited volume," functionally determined networks and local topologies ("islands") can be defined that drive the appropriate repair process at a given damage site. Experimental results of investigations of the chromatin nano-architecture and DNA repair clusters obtained by means of single-molecule localization microscopy offer hints and perspectives that may contribute to verifying the hypothesis.
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Affiliation(s)
- Michael Hausmann
- Kirchhoff-Institute for Physics, Heidelberg University, Heidelberg, Germany.
| | - Georg Hildenbrand
- Kirchhoff-Institute for Physics, Heidelberg University, Heidelberg, Germany
| | - Götz Pilarczyk
- Kirchhoff-Institute for Physics, Heidelberg University, Heidelberg, Germany
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18
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Knoch TA. Simulation of Different Three-Dimensional Models of Whole Interphase Nuclei Compared to Experiments - A Consistent Scale-Bridging Simulation Framework for Genome Organization. Results Probl Cell Differ 2022; 70:495-549. [PMID: 36348120 DOI: 10.1007/978-3-031-06573-6_18] [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: 06/16/2023]
Abstract
The three-dimensional architecture of chromosomes, their arrangement, and dynamics within cell nuclei are still subject of debate. Obviously, the function of genomes-the storage, replication, and transcription of genetic information-has closely coevolved with this architecture and its dynamics, and hence are closely connected. In this work a scale-bridging framework investigates how of the 30 nm chromatin fibre organizes into chromosomes including their arrangement and morphology in the simulation of whole nuclei. Therefore, mainly two different topologies were simulated with corresponding parameter variations and comparing them to experiments: The Multi-Loop-Subcompartment (MLS) model, in which (stable) small loops form (stable) rosettes, connected by chromatin linkers, and the Random-Walk/Giant-Loop (RW/GL) model, in which large loops are attached to a flexible non-protein backbone, were simulated for various loop and linker sizes. The 30 nm chromatin fibre was modelled as a polymer chain with stretching, bending and excluded volume interactions. A spherical boundary potential simulated the confinement to nuclei with different radii. Simulated annealing and Brownian Dynamics methods were applied in a four-step decondensation procedure to generate from metaphase decondensated interphase configurations at thermodynamical equilibrium. Both the MLS and the RW/GL models form chromosome territories, with different morphologies: The MLS rosettes result in distinct subchromosomal domains visible in electron and confocal laser scanning microscopic images. In contrast, the big RW/GL loops lead to a mostly homogeneous chromatin distribution. Even small changes of the model parameters induced significant rearrangements of the chromatin morphology. The low overlap of chromosomes, arms, and subchromosomal domains observed in experiments agrees only with the MLS model. The chromatin density distribution in CLSM image stacks reveals a bimodal behaviour in agreement with recent experiments. Combination of these results with a variety of (spatial distance) measurements favour an MLS like model with loops and linkers of 63 to 126 kbp. The predicted large spaces between the chromatin fibres allow typically sized biological molecules to reach nearly every location in the nucleus by moderately obstructed diffusion and is in disagreement with the much simplified assumption that defined channels between territories for molecular transport as in the Interchromosomal Domain (ICD) hypothesis exist and are necessary for transport. All this is also in agreement with recent selective high-resolution chromosome interaction capture (T2C) experiments, the scaling behaviour of the DNA sequence, the dynamics of the chromatin fibre, the diffusion of molecules, and other measurements. Also all other chromosome topologies can in principle be excluded. In summary, polymer simulations of whole nuclei compared to experimental data not only clearly favour only a stable loop aggregate/rosette like genome architecture whose local topology is tightly connected to the global morphology and dynamics of the cell nucleus and hence can be used for understanding genome organization also in respect to diagnosis and treatment. This is in agreement with and also leads to a general novel framework of genome emergence, function, and evolution.
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Affiliation(s)
- Tobias A Knoch
- Biophysical Genomics, TAKnoch Joined Operations Administrative Office, Mannheim, Germany.
- Human Ecology and Complex Systems, German Society for Human Ecology (DGH), TAKnoch Joined Operations Administrative Office, Mannheim, Germany.
- TAK Renewable Energy UG, TAKnoch Joined Operations Administrative Office, Mannheim, Germany.
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19
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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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20
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Di Stefano M, Nützmann HW. Modeling the 3D genome of plants. Nucleus 2021; 12:65-81. [PMID: 34057011 PMCID: PMC8168717 DOI: 10.1080/19491034.2021.1927503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 04/29/2021] [Accepted: 05/05/2021] [Indexed: 12/11/2022] Open
Abstract
Chromosomes are the carriers of inheritable traits and define cell function and development. This is not only based on the linear DNA sequence of chromosomes but also on the additional molecular information they are associated with, including the transcription machinery, histone modifications, and their three-dimensional folding. The synergistic application of experimental approaches and computer simulations has helped to unveil how these organizational layers of the genome interplay in various organisms. However, such multidisciplinary approaches are still rarely explored in the plant kingdom. Here, we provide an overview of our current knowledge on plant 3D genome organization and review recent efforts to integrate cutting-edge experiments from microscopy and next-generation sequencing approaches with theoretical models. Building on these recent approaches, we propose possible avenues to extend the application of theoretical modeling in the characterization of the 3D genome organization in plants.
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Affiliation(s)
- Marco Di Stefano
- Institute of Human Genetics, Centre National de la Recherche Scientifique, University of Montpellier, Montpellier, France
| | - Hans-Wilhelm Nützmann
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, UK
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21
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Anumukonda K, Francis M, Currie P, Tulenko F, Hsu E. Heavy chain-only antibody genes in fish evolved to generate unique CDR3 repertoire. Eur J Immunol 2021; 52:247-260. [PMID: 34708869 DOI: 10.1002/eji.202149588] [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: 08/18/2021] [Revised: 10/08/2021] [Accepted: 10/26/2021] [Indexed: 11/11/2022]
Abstract
In addition to conventional immunoglobulin, camelids and cartilaginous fish express a special class of antibody that consists only of heavy (H) chain (HCAbs). In the holocephalan elephantfish, there are two HCAb classes, one of which has evolved surprising features. The H-chain genes in cartilaginous fish are organized as 20-200 minigenes, or clusters, each consisting of VH, 1-3 DH, JH gene segments with one set of constant region exons. We report that HHC2 (holocephalan H-chain antibody 2) evolved from IgM H-chain clusters, but its DH gene segments have diverged considerably. The three DH in HHC2 clusters are A-rich, so that one to three potential reading frames for each DH encode lysine and arginine. All three are incorporated into the rearranged VDJ, ensuring that the ligand-binding site carries multiple basic residues, as cDNA sequences demonstrate. The electropositive character in HHC2 CDR3 is accompanied by a paucity of aromatic amino acids, the latter feature at variance to the established, interactive role of tyrosine not only in ligand-binding but generally at interfaces of protein complexes. The selection for these divergent HHC2 features challenges currently accepted ideas on what determines antibody reactivity and molecular recognition.
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Affiliation(s)
- Kamala Anumukonda
- Department of Physiology and Pharmacology, State University of New York Downstate Health Sciences University, Brooklyn, NY, 11203, USA
| | - Malcolm Francis
- National Institute of Water and Atmospheric Research, Wellington, New Zealand
| | - Peter Currie
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, 3800, Australia
| | - Frank Tulenko
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, 3800, Australia
| | - Ellen Hsu
- Department of Physiology and Pharmacology, State University of New York Downstate Health Sciences University, Brooklyn, NY, 11203, USA
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22
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Baizan-Edge A, Stubbs BA, Stubbington MJT, Bolland DJ, Tabbada K, Andrews S, Corcoran AE. IL-7R signaling activates widespread V H and D H gene usage to drive antibody diversity in bone marrow B cells. Cell Rep 2021; 36:109349. [PMID: 34260907 PMCID: PMC8293627 DOI: 10.1016/j.celrep.2021.109349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 04/05/2021] [Accepted: 06/15/2021] [Indexed: 01/09/2023] Open
Abstract
Generation of the primary antibody repertoire requires V(D)J recombination of hundreds of gene segments in the immunoglobulin heavy chain (Igh) locus. The role of interleukin-7 receptor (IL-7R) signaling in Igh recombination has been difficult to partition from its role in B cell survival and proliferation. With a detailed description of the Igh repertoire in murine IL-7Rα-/- bone marrow B cells, we demonstrate that IL-7R signaling profoundly influences VH gene selection during VH-to-DJH recombination. We find skewing toward 3' VH genes during de novo VH-to-DJH recombination more severe than the fetal liver (FL) repertoire and uncover a role for IL-7R signaling in DH-to-JH recombination. Transcriptome and accessibility analyses suggest reduced expression of B lineage transcription factors (TFs) and targets and loss of DH and VH antisense transcription in IL-7Rα-/- B cells. Thus, in addition to its roles in survival and proliferation, IL-7R signaling shapes the Igh repertoire by activating underpinning mechanisms.
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Affiliation(s)
- Amanda Baizan-Edge
- Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Bryony A Stubbs
- Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Michael J T Stubbington
- Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Daniel J Bolland
- Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK; Lymphocyte Signaling and Development Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Kristina Tabbada
- Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK; Lymphocyte Signaling and Development Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Simon Andrews
- Bioinformatics Group, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Anne E Corcoran
- Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK; Lymphocyte Signaling and Development Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK.
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23
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Monfils K, Barakat TS. Models behind the mystery of establishing enhancer-promoter interactions. Eur J Cell Biol 2021; 100:151170. [PMID: 34246183 DOI: 10.1016/j.ejcb.2021.151170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/30/2021] [Accepted: 07/02/2021] [Indexed: 10/20/2022] Open
Abstract
Enhancers and promoters are transcriptional regulatory elements whose facilitated interactions increase gene expression. Enhancer DNA sequences can be located far away from the promoter sequences that they regulate. Currently, the mechanism facilitating the establishment of enhancer-promoter interactions remains unclear. However, mutations causing errors in these interactions have been linked to cancer and disease, further conveying the need to understand the full mechanism. This review discusses multiple models that have been proposed to describe how enhancers go the distance to interact with promoters. Evidence supporting loop formation models is reviewed in addition to more complex hypotheses involving aspects of 3D chromatin organization and phase separation.
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Affiliation(s)
- Kathryn Monfils
- Department of Clinical Genetics, Erasmus MC University Medical Center, PO Box 2040, 3000 CA, Rotterdam, the Netherlands
| | - Tahsin Stefan Barakat
- Department of Clinical Genetics, Erasmus MC University Medical Center, PO Box 2040, 3000 CA, Rotterdam, the Netherlands.
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24
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Impacts of chromatin dynamics and compartmentalization on DNA repair. DNA Repair (Amst) 2021; 105:103162. [PMID: 34182258 DOI: 10.1016/j.dnarep.2021.103162] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/10/2021] [Accepted: 06/17/2021] [Indexed: 11/22/2022]
Abstract
The proper spatial organization of DNA, RNA, and proteins is critical for a variety of cellular processes. The genome is organized into numerous functional units, such as topologically associating domains (TADs), the formation of which is regulated by both proteins and RNA. In addition, a group of chromatin-bound proteins with the ability to undergo liquid-liquid phase separation (LLPS) can affect the spatial organization and compartmentalization of chromatin, RNA, and proteins by forming condensates, conferring unique properties to specific chromosomal regions. Although the regulation of DNA repair by histone modifications and chromatin accessibility is well established, the impacts of higher-order chromatin and protein organization on the DNA damage response (DDR) have not been appreciated until recently. In this review, we will focus on the movement of chromatin during the DDR, the compartmentalization of DDR proteins via LLPS, and the roles of membraneless nuclear bodies and transcription in DNA repair. With this backdrop, we will discuss the importance of the spatial organization of chromatin and proteins for the maintenance of genome integrity.
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25
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Scourzic L, Salataj E, Apostolou E. Deciphering the Complexity of 3D Chromatin Organization Driving Lymphopoiesis and Lymphoid Malignancies. Front Immunol 2021; 12:669881. [PMID: 34054841 PMCID: PMC8160312 DOI: 10.3389/fimmu.2021.669881] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/26/2021] [Indexed: 12/18/2022] Open
Abstract
Proper lymphopoiesis and immune responses depend on the spatiotemporal control of multiple processes, including gene expression, DNA recombination and cell fate decisions. High-order 3D chromatin organization is increasingly appreciated as an important regulator of these processes and dysregulation of genomic architecture has been linked to various immune disorders, including lymphoid malignancies. In this review, we present the general principles of the 3D chromatin topology and its dynamic reorganization during various steps of B and T lymphocyte development and activation. We also discuss functional interconnections between architectural, epigenetic and transcriptional changes and introduce major key players of genomic organization in B/T lymphocytes. Finally, we present how alterations in architectural factors and/or 3D genome organization are linked to dysregulation of the lymphopoietic transcriptional program and ultimately to hematological malignancies.
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Affiliation(s)
| | | | - Effie Apostolou
- Sanford I. Weill Department of Medicine, Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY, United States
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26
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Liu S, Zhao K. The Toolbox for Untangling Chromosome Architecture in Immune Cells. Front Immunol 2021; 12:670884. [PMID: 33995409 PMCID: PMC8120992 DOI: 10.3389/fimmu.2021.670884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 04/06/2021] [Indexed: 12/19/2022] Open
Abstract
The code of life is not only encrypted in the sequence of DNA but also in the way it is organized into chromosomes. Chromosome architecture is gradually being recognized as an important player in regulating cell activities (e.g., controlling spatiotemporal gene expression). In the past decade, the toolbox for elucidating genome structure has been expanding, providing an opportunity to explore this under charted territory. In this review, we will introduce the recent advancements in approaches for mapping spatial organization of the genome, emphasizing applications of these techniques to immune cells, and trying to bridge chromosome structure with immune cell activities.
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Affiliation(s)
- Shuai Liu
- Laboratory of Epigenome Biology, Systems Biology Center, NHLBI, NIH, Bethesda, MD, United States
| | - Keji Zhao
- Laboratory of Epigenome Biology, Systems Biology Center, NHLBI, NIH, Bethesda, MD, United States
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27
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Pongubala JMR, Murre C. Spatial Organization of Chromatin: Transcriptional Control of Adaptive Immune Cell Development. Front Immunol 2021; 12:633825. [PMID: 33854505 PMCID: PMC8039525 DOI: 10.3389/fimmu.2021.633825] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 03/03/2021] [Indexed: 12/11/2022] Open
Abstract
Higher-order spatial organization of the genome into chromatin compartments (permissive and repressive), self-associating domains (TADs), and regulatory loops provides structural integrity and offers diverse gene regulatory controls. In particular, chromatin regulatory loops, which bring enhancer and associated transcription factors in close spatial proximity to target gene promoters, play essential roles in regulating gene expression. The establishment and maintenance of such chromatin loops are predominantly mediated involving CTCF and the cohesin machinery. In recent years, significant progress has been made in revealing how loops are assembled and how they modulate patterns of gene expression. Here we will discuss the mechanistic principles that underpin the establishment of three-dimensional (3D) chromatin structure and how changes in chromatin structure relate to alterations in gene programs that establish immune cell fate.
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Affiliation(s)
| | - Cornelis Murre
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, United States
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28
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Rogers CH, Mielczarek O, Corcoran AE. Dynamic 3D Locus Organization and Its Drivers Underpin Immunoglobulin Recombination. Front Immunol 2021; 11:633705. [PMID: 33679727 PMCID: PMC7930373 DOI: 10.3389/fimmu.2020.633705] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 12/30/2020] [Indexed: 01/10/2023] Open
Abstract
A functional adaptive immune system must generate enormously diverse antigen receptor (AgR) repertoires from a limited number of AgR genes, using a common mechanism, V(D)J recombination. The AgR loci are among the largest in the genome, and individual genes must overcome huge spatial and temporal challenges to co-localize with optimum variability. Our understanding of the complex mechanisms involved has increased enormously, due in part to new technologies for high resolution mapping of AgR structure and dynamic movement, underpinning mechanisms, and resulting repertoires. This review will examine these advances using the paradigm of the mouse immunoglobulin heavy chain (Igh) locus. We will discuss the key regulatory elements implicated in Igh locus structure. Recent next generation repertoire sequencing methods have shown that local chromatin state at V genes contribute to recombination efficiency. Next on the multidimensional scale, we will describe imaging studies that provided the first picture of the large-scale dynamic looping and contraction the Igh locus undergoes during recombination. We will discuss chromosome conformation capture (3C)-based technologies that have provided higher resolution pictures of Igh locus structure, including the different models that have evolved. We will consider the key transcription factors (PAX5, YY1, E2A, Ikaros), and architectural factors, CTCF and cohesin, that regulate these processes. Lastly, we will discuss a plethora of recent exciting mechanistic findings. These include Rag recombinase scanning for convergent RSS sequences within DNA loops; identification of Igh loop extrusion, and its putative role in Rag scanning; the roles of CTCF, cohesin and cohesin loading factor, WAPL therein; a new phase separation model for Igh locus compartmentalization. We will draw these together and conclude with some horizon-scanning and unresolved questions.
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Affiliation(s)
- Carolyn H Rogers
- Lymphocyte Signalling and Development Programme, Babraham Institute, Cambridge, United Kingdom
| | - Olga Mielczarek
- Nuclear Dynamics Programme, Babraham Institute, Cambridge, United Kingdom
| | - Anne E Corcoran
- Lymphocyte Signalling and Development Programme, Babraham Institute, Cambridge, United Kingdom
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29
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Søndergaard E, Rauch A, Michaut M, Rapin N, Rehn M, Wilhelmson AS, Camponeschi A, Hasemann MS, Bagger FO, Jendholm J, Knudsen KJ, Mandrup S, Mårtensson IL, Porse BT. ERG Controls B Cell Development by Promoting Igh V-to-DJ Recombination. Cell Rep 2020; 29:2756-2769.e6. [PMID: 31775043 DOI: 10.1016/j.celrep.2019.10.098] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 08/28/2019] [Accepted: 10/24/2019] [Indexed: 11/26/2022] Open
Abstract
B cell development depends on the coordinated expression and cooperation of several transcription factors. Here we show that the transcription factor ETS-related gene (ERG) is crucial for normal B cell development and that its deletion results in a substantial loss of bone marrow B cell progenitors and peripheral B cells, as well as a skewing of splenic B cell populations. We find that ERG-deficient B lineage cells exhibit an early developmental block at the pre-B cell stage and proliferate less. The cells fail to express the immunoglobulin heavy chain due to inefficient V-to-DJ recombination, and cells that undergo recombination display a strong bias against incorporation of distal V gene segments. Furthermore, antisense transcription at PAX5-activated intergenic repeat (PAIR) elements, located in the distal region of the Igh locus, depends on ERG. These findings show that ERG serves as a critical regulator of B cell development by ensuring efficient and balanced V-to-DJ recombination.
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Affiliation(s)
- Elisabeth Søndergaard
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark; Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen N, Denmark; Danish Stem Cell Centre (DanStem) Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Alexander Rauch
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark
| | - Magali Michaut
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark; Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen N, Denmark; Danish Stem Cell Centre (DanStem) Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark; The Bioinformatics Centre, Department of Biology, Faculty of Natural Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Nicolas Rapin
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark; Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen N, Denmark; Danish Stem Cell Centre (DanStem) Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark; The Bioinformatics Centre, Department of Biology, Faculty of Natural Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Matilda Rehn
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark; Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen N, Denmark; Danish Stem Cell Centre (DanStem) Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Anna S Wilhelmson
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark; Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen N, Denmark; Danish Stem Cell Centre (DanStem) Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Alessandro Camponeschi
- Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Marie S Hasemann
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark; Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen N, Denmark; Danish Stem Cell Centre (DanStem) Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Frederik O Bagger
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark; Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen N, Denmark; Danish Stem Cell Centre (DanStem) Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark; The Bioinformatics Centre, Department of Biology, Faculty of Natural Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Johan Jendholm
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark; Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen N, Denmark; Danish Stem Cell Centre (DanStem) Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Kasper J Knudsen
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark; Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen N, Denmark; Danish Stem Cell Centre (DanStem) Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Susanne Mandrup
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark
| | - Inga-Lill Mårtensson
- Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Bo T Porse
- The Finsen Laboratory, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark; Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen N, Denmark; Danish Stem Cell Centre (DanStem) Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark.
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30
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Saluja D, Bar-On T, Hayam G, Kassotis J, Kostis WJ, Coromilas J. The Rapid Prediction of Focal Wavefront Origins: Integration With a 3-Dimensional Mapping System. JACC Clin Electrophysiol 2020; 6:1478-1487. [PMID: 33213807 DOI: 10.1016/j.jacep.2020.05.024] [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: 02/12/2020] [Revised: 05/20/2020] [Accepted: 05/20/2020] [Indexed: 10/23/2022]
Abstract
OBJECTIVES This study assessed the accuracy of an algorithm that predicts the origin of focal arrhythmias using a limited number of data points. BACKGROUND Despite advances in technology, ablations can be time-consuming, and activation mapping continues to have inherent limitations. The authors developed an algorithm that can predict the origin of a focal wavefront using the location and activation timing information in 2 pairs of sampled points. This algorithm was incorporated into an electroanatomic mapping (EAM) system to assess its accuracy in a 3-dimensional clinical environment. METHODS EAM data from patients who underwent successful ablation of a focal wavefront using the CARTO3 system were loaded onto an offline version of the software modified to contain the algorithm. Prediction curves were retrospectively generated. Predictive accuracy, defined as the distance between true and predicted origin wavefront origins, was measured. RESULTS Seventeen wavefronts in as many patients (2 with atrial tachycardia, 3 with orthodromic re-entrant tachycardia, 8 with premature ventricular complex and/or ventricular tachycardia, 4 with focal pulmonary vein isolation breakthroughs) were studied. Thirty-three origin predictions were attempted (1.9 ± 0.4 per patient) using 132 points. Predictions were successfully calculated in 31 of 33 (93.9%) attempts and were accurate to within 5.7 ± 6.9 mm. Individual prediction curves were accurate to within 3.0 ± 4.7 mm. CONCLUSIONS Focal wavefront origins may be accurately predicted in 3 dimensions using a novel algorithm incorporated into an EAM system.
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Affiliation(s)
- Deepak Saluja
- Department of Medicine, Columbia University, New York, New York, USA.
| | | | | | - John Kassotis
- Department of Medicine, Rutgers-Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA
| | - William J Kostis
- Department of Medicine, Rutgers-Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA
| | - James Coromilas
- Department of Medicine, Rutgers-Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA
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31
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Hill L, Ebert A, Jaritz M, Wutz G, Nagasaka K, Tagoh H, Kostanova-Poliakova D, Schindler K, Sun Q, Bönelt P, Fischer M, Peters JM, Busslinger M. Wapl repression by Pax5 promotes V gene recombination by Igh loop extrusion. Nature 2020; 584:142-147. [PMID: 32612238 PMCID: PMC7116900 DOI: 10.1038/s41586-020-2454-y] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 04/09/2020] [Indexed: 01/04/2023]
Abstract
Nuclear processes, such as V(D)J recombination, are orchestrated by the three-dimensional organization of chromosomes at multiple levels, including compartments1 and topologically associated domains (TADs)2,3 consisting of chromatin loops4. TADs are formed by chromatin-loop extrusion5-7, which depends on the loop-extrusion function of the ring-shaped cohesin complex8-12. Conversely, the cohesin-release factor Wapl13,14 restricts loop extension10,15. The generation of a diverse antibody repertoire, providing humoral immunity to pathogens, requires the participation of all V genes in V(D)J recombination16, which depends on contraction of the 2.8-Mb-long immunoglobulin heavy chain (Igh) locus by Pax517,18. However, how Pax5 controls Igh contraction in pro-B cells remains unknown. Here we demonstrate that locus contraction is caused by loop extrusion across the entire Igh locus. Notably, the expression of Wapl is repressed by Pax5 specifically in pro-B and pre-B cells, facilitating extended loop extrusion by increasing the residence time of cohesin on chromatin. Pax5 mediates the transcriptional repression of Wapl through a single Pax5-binding site by recruiting the polycomb repressive complex 2 to induce bivalent chromatin at the Wapl promoter. Reduced Wapl expression causes global alterations in the chromosome architecture, indicating that the potential to recombine all V genes entails structural changes of the entire genome in pro-B cells.
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Affiliation(s)
- Louisa Hill
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Anja Ebert
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Markus Jaritz
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Gordana Wutz
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Kota Nagasaka
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Hiromi Tagoh
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
- Ludwig Institute for Cancer Research, University of Oxford, Oxford, UK
| | | | - Karina Schindler
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Qiong Sun
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Peter Bönelt
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Maria Fischer
- 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
| | - Meinrad Busslinger
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria.
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32
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Tsokos GC. Autoimmunity and organ damage in systemic lupus erythematosus. Nat Immunol 2020; 21:605-614. [PMID: 32367037 PMCID: PMC8135909 DOI: 10.1038/s41590-020-0677-6] [Citation(s) in RCA: 280] [Impact Index Per Article: 70.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 03/31/2020] [Indexed: 01/07/2023]
Abstract
Impressive progress has been made over the last several years toward understanding how almost every aspect of the immune system contributes to the expression of systemic autoimmunity. In parallel, studies have shed light on the mechanisms that contribute to organ inflammation and damage. New approaches that address the complicated interaction between genetic variants, epigenetic processes, sex and the environment promise to enlighten the multitude of pathways that lead to what is clinically defined as systemic lupus erythematosus. It is expected that each patient owns a unique 'interactome', which will dictate specific treatment.
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Affiliation(s)
- George C Tsokos
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA.
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33
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Di Stefano M, Stadhouders R, Farabella I, Castillo D, Serra F, Graf T, Marti-Renom MA. Transcriptional activation during cell reprogramming correlates with the formation of 3D open chromatin hubs. Nat Commun 2020; 11:2564. [PMID: 32444798 PMCID: PMC7244774 DOI: 10.1038/s41467-020-16396-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 05/01/2020] [Indexed: 12/22/2022] Open
Abstract
Chromosome structure is a crucial regulatory factor for a wide range of nuclear processes. Chromosome conformation capture (3C)-based experiments combined with computational modelling are pivotal for unveiling 3D chromosome structure. Here, we introduce TADdyn, a tool that integrates time-course 3C data, restraint-based modelling, and molecular dynamics to simulate the structural rearrangements of genomic loci in a completely data-driven way. We apply TADdyn on in situ Hi-C time-course experiments studying the reprogramming of murine B cells to pluripotent cells, and characterize the structural rearrangements that take place upon changes in the transcriptional state of 21 genomic loci of diverse expression dynamics. By measuring various structural and dynamical properties, we find that during gene activation, the transcription starting site contacts with open and active regions in 3D chromatin domains. We propose that these 3D hubs of open and active chromatin may constitute a general feature to trigger and maintain gene transcription.
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Affiliation(s)
- Marco Di Stefano
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, 08028, Barcelona, Spain. .,Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Dr. Aiguader 88, 08003, Barcelona, Spain.
| | - Ralph Stadhouders
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Dr. Aiguader 88, 08003, Barcelona, Spain.,Department of Pulmonary Medicine and Department of Cell Biology, Erasmus MC, Rotterdam, the Netherlands
| | - Irene Farabella
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, 08028, Barcelona, Spain.,Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Dr. Aiguader 88, 08003, Barcelona, Spain
| | - David Castillo
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, 08028, Barcelona, Spain.,Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Dr. Aiguader 88, 08003, Barcelona, Spain
| | - François Serra
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, 08028, Barcelona, Spain.,Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Dr. Aiguader 88, 08003, Barcelona, Spain.,Computational Biology Group-Barcelona Supercomputing Center (BSC), 08034, Barcelona, Spain
| | - Thomas Graf
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Dr. Aiguader 88, 08003, Barcelona, Spain.
| | - Marc A Marti-Renom
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, 08028, Barcelona, Spain. .,Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Dr. Aiguader 88, 08003, Barcelona, Spain. .,Universitat Pompeu Fabra (UPF), 08002, Barcelona, Spain. .,ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain.
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34
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Maji A, Ahmed JA, Roy S, Chakrabarti B, Mitra MK. A Lamin-Associated Chromatin Model for Chromosome Organization. Biophys J 2020; 118:3041-3050. [PMID: 32492372 DOI: 10.1016/j.bpj.2020.05.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 05/09/2020] [Accepted: 05/12/2020] [Indexed: 12/22/2022] Open
Abstract
We propose a simple model for chromatin organization based on the interaction of the chromatin fibers with lamin proteins along the nuclear membrane. Lamin proteins are known to be a major factor that influences chromatin organization and hence gene expression in the cells. We provide a quantitative understanding of lamin-associated chromatin organization in a crowded macromolecular environment by systematically varying the heteropolymer segment distribution and the strength of the lamin-chromatin attractive interaction. Our minimal polymer model reproduces the formation of lamin-associated-domains and provides an in silico tool for quantifying domain length distributions for different distributions of heteropolymer segments. We show that a Gaussian distribution of heteropolymer segments, coupled with strong lamin-chromatin interactions, can qualitatively reproduce observed length distributions of lamin-associated-domains. Further, lamin-mediated interaction can enhance the formation of chromosome territories as well as the organization of chromatin into tightly packed heterochromatin and the loosely packed gene-rich euchromatin regions.
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Affiliation(s)
- Ajoy Maji
- Department of Physics, Indian Institute of Technology Bombay, Mumbai, India
| | - Jahir A Ahmed
- AKI's Poona College of Arts, Science and Commerce, Camp, Pune, India
| | - Subhankar Roy
- Saha Institute of Nuclear Physics, HBNI, Kolkata, India
| | | | - Mithun K Mitra
- Department of Physics, Indian Institute of Technology Bombay, Mumbai, India.
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35
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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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36
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McCord RP, Kaplan N, Giorgetti L. Chromosome Conformation Capture and Beyond: Toward an Integrative View of Chromosome Structure and Function. Mol Cell 2020; 77:688-708. [PMID: 32001106 PMCID: PMC7134573 DOI: 10.1016/j.molcel.2019.12.021] [Citation(s) in RCA: 110] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Rapidly developing technologies have recently fueled an exciting era of discovery in the field of chromosome structure and nuclear organization. In addition to chromosome conformation capture (3C) methods, new alternative techniques have emerged to study genome architecture and biological processes in the nucleus, often in single or living cells. This sets an unprecedented stage for exploring the mechanisms that link chromosome structure and biological function. Here we review popular as well as emerging approaches to study chromosome organization, focusing on the contribution of complementary methodologies to our understanding of structures revealed by 3C methods and their biological implications, and discuss the next technical and conceptual frontiers.
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Affiliation(s)
- Rachel Patton McCord
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | - Noam Kaplan
- Department of Physiology, Biophysics and Systems Biology, Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Luca Giorgetti
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.
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37
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Barajas-Mora EM, Feeney AJ. Enhancers as regulators of antigen receptor loci three-dimensional chromatin structure. Transcription 2019; 11:37-51. [PMID: 31829768 DOI: 10.1080/21541264.2019.1699383] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Enhancers are defined as regulatory elements that control transcription in a cell-type and developmental stage-specific manner. They achieve this by physically interacting with their cognate gene promoters. Significantly, these interactions can occur through long genomic distances since enhancers may not be near their cognate promoters. The optimal coordination of enhancer-regulated transcription is essential for the function and identity of the cell. Although great efforts to fully understand the principles of this type of regulation are ongoing, other potential functions of the long-range chromatin interactions (LRCIs) involving enhancers are largely unexplored. We recently uncovered a new role for enhancer elements in determining the three-dimensional (3D) structure of the immunoglobulin kappa (Igκ) light chain receptor locus suggesting a structural function for these DNA elements. This enhancer-mediated locus configuration shapes the resulting Igκ repertoire. We also propose a role for enhancers as critical components of sub-topologically associating domain (subTAD) formation and nuclear spatial localization.
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Affiliation(s)
- E Mauricio Barajas-Mora
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA.,Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Ann J Feeney
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA
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38
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Merlotti A, Rosa A, Remondini D. Merging 1D and 3D genomic information: Challenges in modelling and validation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1863:194415. [PMID: 31672524 DOI: 10.1016/j.bbagrm.2019.194415] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/25/2019] [Accepted: 07/25/2019] [Indexed: 12/23/2022]
Abstract
Genome organization in eukaryotes during interphase stems from the delicate balance between non-random correlations present in the DNA polynucleotide linear sequence and the physico/chemical reactions which shape continuously the form and structure of DNA and chromatin inside the nucleus of the cell. It is now clear that these mechanisms have a key role in important processes like gene regulation, yet the detailed ways they act simultaneously and, eventually, come to influence each other even across very different length-scales remain largely unexplored. In this paper, we recapitulate some of the main results concerning gene regulatory and physical mechanisms, in relation to the information encoded in the 1D sequence and the 3D folding structure of DNA. In particular, we stress how reciprocal crossfeeding between 1D and 3D models may provide original insight into how these complex processes work and influence each other. This article is part of a Special Issue entitled: Transcriptional Profiles and Regulatory Gene Networks edited by Dr. Dr. Federico Manuel Giorgi and Dr. Shaun Mahony.
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Affiliation(s)
- Alessandra Merlotti
- Department of Physics and Astronomy (DIFA), University of Bologna, Viale Berti Pichat 6/2, Bologna 40127, Italy; INFN Sez., Bologna, Italy.
| | - Angelo Rosa
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136 Trieste, (Italy).
| | - Daniel Remondini
- Department of Physics and Astronomy (DIFA), University of Bologna, Viale Berti Pichat 6/2, Bologna 40127, Italy; INFN Sez., Bologna, Italy.
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39
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Hedrich CM, Tsokos G. SNPs talk to genes using landlines: long-range chromatin interactions link genetic risk with epigenetic patterns in Takayasu arteritis. Ann Rheum Dis 2019; 78:1293-1295. [PMID: 31391179 DOI: 10.1136/annrheumdis-2019-215957] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 07/29/2019] [Accepted: 07/29/2019] [Indexed: 01/08/2023]
Affiliation(s)
- Christian M Hedrich
- Department of Women's and Children's Health, Institute of Translational Medicine, University of Liverpool School of Life Sciences, Liverpool, UK .,Department of Paediatric Rheumatology, Alder Hey Children's NHS Foundation Trust Hospital, Liverpool, UK
| | - George Tsokos
- Division of Rheumatology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.,Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
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40
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Yildirim A, Feig M. High-resolution 3D models of Caulobacter crescentus chromosome reveal genome structural variability and organization. Nucleic Acids Res 2019. [PMID: 29529244 PMCID: PMC5934669 DOI: 10.1093/nar/gky141] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
High-resolution three-dimensional models of Caulobacter crescentus nucleoid structures were generated via a multi-scale modeling protocol. Models were built as a plectonemically supercoiled circular DNA and by incorporating chromosome conformation capture based data to generate an ensemble of base pair resolution models consistent with the experimental data. Significant structural variability was found with different degrees of bending and twisting but with overall similar topologies and shapes that are consistent with C. crescentus cell dimensions. The models allowed a direct mapping of the genomic sequence onto the three-dimensional nucleoid structures. Distinct spatial distributions were found for several genomic elements such as AT-rich sequence elements where nucleoid associated proteins (NAPs) are likely to bind, promoter sites, and some genes with common cellular functions. These findings shed light on the correlation between the spatial organization of the genome and biological functions.
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Affiliation(s)
- Asli Yildirim
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Michael Feig
- Department of Biochemistry & Molecular Biology, Michigan State University, MI 48824, USA
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41
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Khanna N, Zhang Y, Lucas JS, Dudko OK, Murre C. Chromosome dynamics near the sol-gel phase transition dictate the timing of remote genomic interactions. Nat Commun 2019; 10:2771. [PMID: 31235807 PMCID: PMC6591236 DOI: 10.1038/s41467-019-10628-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 05/20/2019] [Indexed: 11/08/2022] Open
Abstract
Diverse antibody repertoires are generated through remote genomic interactions involving immunoglobulin variable (VH), diversity (DH) and joining (JH) gene segments. How such interactions are orchestrated remains unknown. Here we develop a strategy to track VH-DHJH motion in B-lymphocytes. We find that VH and DHJH segments are trapped in configurations that allow only local motion, such that spatially proximal segments remain in proximity, while spatially remote segments remain remote. Within a subset of cells, however, abrupt changes in VH-DHJH motion are observed, plausibly caused by temporal alterations in chromatin configurations. Comparison of experimental and simulated data suggests that constrained motion is imposed by a network of cross-linked chromatin chains characteristic of a gel phase, yet poised near the sol phase, a solution of independent chromatin chains. These results suggest that chromosome organization near the sol-gel phase transition dictates the timing of genomic interactions to orchestrate gene expression and somatic recombination.
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Affiliation(s)
- Nimish Khanna
- Division of Biological Sciences, 0377, Department of Molecular Biology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Yaojun Zhang
- Princeton Center for Theoretical Science, Princeton University, Princeton, NJ, 08544, USA
| | - Joseph S Lucas
- Division of Biological Sciences, 0377, Department of Molecular Biology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Olga K Dudko
- Department of Physics, University of California, San Diego, La Jolla, CA, 92093, USA.
| | - Cornelis Murre
- Division of Biological Sciences, 0377, Department of Molecular Biology, University of California, San Diego, La Jolla, CA, 92093, USA.
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42
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Transcription factors and 3D genome conformation in cell-fate decisions. Nature 2019; 569:345-354. [PMID: 31092938 DOI: 10.1038/s41586-019-1182-7] [Citation(s) in RCA: 281] [Impact Index Per Article: 56.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 03/19/2019] [Indexed: 12/31/2022]
Abstract
How cells adopt different identities has long fascinated biologists. Signal transduction in response to environmental cues results in the activation of transcription factors that determine the gene-expression program characteristic of each cell type. Technological advances in the study of 3D chromatin folding are bringing the role of genome conformation in transcriptional regulation to the fore. Characterizing this role of genome architecture has profound implications, not only for differentiation and development but also for diseases including developmental malformations and cancer. Here we review recent studies indicating that the interplay between transcription and genome conformation is a driving force for cell-fate decisions.
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43
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Tsuyama N, Abe Y, Yanagi A, Yanai Y, Sugai M, Katafuchi A, Kawamura F, Kamiya K, Sakai A. Induction of t(11;14) IgH enhancer/promoter- cyclin D1 gene translocation using CRISPR/Cas9. Oncol Lett 2019; 18:275-282. [PMID: 31289497 PMCID: PMC6539856 DOI: 10.3892/ol.2019.10303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 04/18/2019] [Indexed: 12/13/2022] Open
Abstract
Chromosomal translocation is a key process in the oncogenic transformation of somatic cells. Previously, artificial induction of chromosomal translocation was performed using homologous recombination-mediated loxP labeling of target regions followed by Cre-mediated recombination. Recent progress in genome editing techniques has facilitated the easier induction of artificial translocation by cutting two targeted genome sequences from different chromosomes. The present study established a system to induce t(11;14)(q13;q32), which is observed primarily in multiple myeloma (MM) and involves the repositioning of the cyclin D1 (CCND1) gene downstream of the immunoglobulin heavy chain (IgH) constant region enhancers by translocation. The placing of tandem gRNAs designed to cut both the IgH Eµ and CCND1 15-kb upstream regions in lentiCRISPRv2 enabled the induction of chromosomal translocation in 293T cells, with confirmation by translocation-specific PCR and fluorescence in situ hybridization probing with IgH and CCND1. At the translocation junctions, small deletions and the addition of DNA sequences (indels) were observed in several clones. Cloned cells with t(11;14) exhibited slower growth and lower CCND1 mRNA expression compared to the parent cells, presenting the opposite phenomena induced by t(11;14) in MM cells, indicating that the silent IgH gene juxtaposed to CCND1 may negatively affect CCND1 gene expression and cell proliferation in the non-B lymphocyte lineage. Therefore, the present study achieved the induction of silent promoter/enhancer translocation in t(11;14)(q13;q32) as a preparatory experiment to study the role of IgH constant region enhancer-driven CCND1 overexpression in oncogenic transformation processes in B lymphocytes.
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Affiliation(s)
- Naohiro Tsuyama
- Department of Radiation Life Sciences, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Yu Abe
- Department of Radiation Life Sciences, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Aki Yanagi
- Department of Radiation Life Sciences, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Yukari Yanai
- Department of Radiation Life Sciences, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Misaki Sugai
- Department of Radiation Life Sciences, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Atsushi Katafuchi
- Department of Radiation Life Sciences, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Fumihiko Kawamura
- Department of Radiation Life Sciences, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Kenji Kamiya
- Department of Experimental Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Minami-ku, Hiroshima 734-8553, Japan
| | - Akira Sakai
- Department of Radiation Life Sciences, Fukushima Medical University, Fukushima 960-1295, Japan
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44
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Abstract
Vast repertoires of unique antigen receptors are created in developing lymphocytes. The antigen receptor loci contain many variable (V), diversity (D), and joining (J) gene segments that are arrayed across very large genomic expanses and are joined to form variable-region exons. This process creates the potential for an organism to respond to large numbers of different pathogens. Here, we consider the underlying molecular mechanisms that favor some V genes for recombination prior to selection of the final antigen receptor repertoire. We discuss chromatin structures that form in antigen receptor loci to permit spatial proximity among the V, D, and J gene segments and how these relate to the generation of antigen receptor diversity.
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Affiliation(s)
- Amy L Kenter
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL, 60612-7344, USA
| | - Ann J Feeney
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, 92037, USA
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45
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Aresta-Branco F, Erben E, Papavasiliou FN, Stebbins CE. Mechanistic Similarities between Antigenic Variation and Antibody Diversification during Trypanosoma brucei Infection. Trends Parasitol 2019; 35:302-315. [PMID: 30826207 DOI: 10.1016/j.pt.2019.01.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/19/2019] [Accepted: 01/23/2019] [Indexed: 02/06/2023]
Abstract
Trypanosoma brucei, which causes African trypanosomiasis, avoids immunity by periodically switching its surface composition. The parasite is coated by 10 million identical, monoallelically expressed variant surface glycoprotein (VSG) molecules. Multiple distinct parasites (with respect to their VSG coat) coexist simultaneously during each wave of parasitemia. This substantial antigenic load is countered by B cells whose antigen receptors (antibodies or immunoglobulins) are also monoallelically expressed, and that diversify dynamically to counter each variant antigen. Here we examine parallels between the processes that generate VSGs and antibodies. We also discuss current insights into VSG mRNA regulation that may inform the emerging field of Ig mRNA biology. We conclude by extending the parallels between VSG and Ig to the protein level.
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Affiliation(s)
- Francisco Aresta-Branco
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany; Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany; These authors contributed equally to this work
| | - Esteban Erben
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany; These authors contributed equally to this work
| | - F Nina Papavasiliou
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany.
| | - C Erec Stebbins
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany.
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46
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Kamali AN, Noorbakhsh SM, Hamedifar H, Jadidi-Niaragh F, Yazdani R, Bautista JM, Azizi G. A role for Th1-like Th17 cells in the pathogenesis of inflammatory and autoimmune disorders. Mol Immunol 2018; 105:107-115. [PMID: 30502718 DOI: 10.1016/j.molimm.2018.11.015] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 11/17/2018] [Accepted: 11/21/2018] [Indexed: 12/21/2022]
Abstract
The T helper 17 (Th17) cells contain a dynamic subset of CD4+ T-cells that are able to develop into other different lineage subsets, including the Th1-like Th17 cells. These cells co-express retinoic acid-related orphan receptor gamma t (RORγt) and transcription factor T-box-expressed-in-T-cells (T-bet) and produce both interleukin (IL)-17 and interferon (IFN)-γ. Recent reports have shown that Th1-like Th17 cells play crucial roles in the pathogenesis of autoimmune diseases such as inflammatory bowel disease, multiple sclerosis and rheumatoid arthritis, as well as, some primary immunodeficiency with autoimmune features. Here, the actual mechanisms for Th17 cells plasticity to Th1-like Th17 cells are discussed and reviewed in association to the role that Th1-like Th17 cells have on inflammatory and autoimmune disorders.
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Affiliation(s)
- Ali N Kamali
- CinnaGen Medical Biotechnology Research Center, Alborz University of Medical Sciences, Karaj, Iran
| | | | - Haleh Hamedifar
- CinnaGen Medical Biotechnology Research Center, Alborz University of Medical Sciences, Karaj, Iran
| | - Farhad Jadidi-Niaragh
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Immunology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Reza Yazdani
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - José M Bautista
- Department of Biochemistry and Molecular Biology, Complutense University of Madrid, Faculty of Veterinary Sciences, 28040, Madrid, Spain; Research Institute Hospital 12 de Octubre, Madrid, 28041, Spain
| | - Gholamreza Azizi
- Non-Communicable Diseases Research Center, Alborz University of Medical Sciences, Karaj, Iran; Department of Immunology, School of Medicine, Alborz University of Medical Sciences, Karaj, Iran.
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47
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Barajas-Mora EM, Kleiman E, Xu J, Carrico NC, Lu H, Oltz EM, Murre C, Feeney AJ. A B-Cell-Specific Enhancer Orchestrates Nuclear Architecture to Generate a Diverse Antigen Receptor Repertoire. Mol Cell 2018; 73:48-60.e5. [PMID: 30449725 DOI: 10.1016/j.molcel.2018.10.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 07/16/2018] [Accepted: 10/08/2018] [Indexed: 12/20/2022]
Abstract
The genome is organized into topologically associated domains (TADs) that enclose smaller subTADs. Here, we identify and characterize an enhancer that is located in the middle of the V gene region of the immunoglobulin kappa light chain (Igκ) locus that becomes active preceding the stage at which this locus undergoes V(D)J recombination. This enhancer is a hub of long-range chromatin interactions connecting subTADs in the V gene region with the recombination center at the J genes. Deletion of this element results in a highly altered long-range chromatin interaction pattern across the locus and, importantly, affects individual V gene utilization locus-wide. These results indicate the existence of an enhancer-dependent framework in the Igκ locus and further suggest that the composition of the diverse antibody repertoire is regulated in a subTAD-specific manner. This enhancer thus plays a structural role in orchestrating the proper folding of the Igκ locus in preparation for V(D)J recombination.
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Affiliation(s)
- E Mauricio Barajas-Mora
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Eden Kleiman
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jeffrey Xu
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Nancy C Carrico
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Hanbin Lu
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Eugene M Oltz
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Cornelis Murre
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ann J Feeney
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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48
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Le Treut G, Képès F, Orland H. A Polymer Model for the Quantitative Reconstruction of Chromosome Architecture from HiC and GAM Data. Biophys J 2018; 115:2286-2294. [PMID: 30527448 DOI: 10.1016/j.bpj.2018.10.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 10/03/2018] [Accepted: 10/26/2018] [Indexed: 01/03/2023] Open
Abstract
It is widely believed that the folding of the chromosome in the nucleus has a major effect on genetic expression. For example, coregulated genes in several species have been shown to colocalize in space despite being far away on the DNA sequence. In this manuscript, we present a new, to our knowledge, method to model the three-dimensional structure of the chromosome in live cells based on DNA-DNA interactions measured in high-throughput chromosome conformation capture experiments and genome architecture mapping. Our approach incorporates a polymer model and directly uses the contact probabilities measured in high-throughput chromosome conformation capture experiments and genome architecture mapping experiments rather than estimates of average distances between genomic loci. Specifically, we model the chromosome as a Gaussian polymer with harmonic interactions and extract the coupling coefficients best reproducing the experimental contact probabilities. In contrast to existing methods, we give an exact expression of the contact probabilities at thermodynamic equilibrium. The Gaussian effective model reconstructed with our method reproduces experimental contacts with high accuracy. We also show how Brownian dynamics simulations of our reconstructed Gaussian effective model can be used to study chromatin organization and possibly give some clue about its dynamics.
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Affiliation(s)
- Guillaume Le Treut
- Department of Physics, University of California San Diego, La Jolla, California.
| | - François Képès
- institute of Systems and Synthetic Biology, Genopole, CNRS, UEVE, Université Paris-Saclay, Évry, France
| | - Henri Orland
- Institut de Physique Théorique, CEA, CNRS-URA 2306, Gif-sur-Yvette, France; Beijing Computational Science Research Center, Beijing, China
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49
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Challenges and guidelines toward 4D nucleome data and model standards. Nat Genet 2018; 50:1352-1358. [PMID: 30262815 DOI: 10.1038/s41588-018-0236-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 07/19/2018] [Indexed: 11/09/2022]
Abstract
Due to recent advances in experimental and theoretical approaches, the dynamic three-dimensional organization (3D) of the nucleus has become a very active area of research in life sciences. We now understand that the linear genome is folded in ways that may modulate how genes are expressed during the basic functioning of cells. Importantly, it is now possible to build 3D models of how the genome folds within the nucleus and changes over time (4D). Because genome folding influences its function, this opens exciting new possibilities to broaden our understanding of the mechanisms that determine cell fate. However, the rapid evolution of methods and the increasing complexity of data can result in ambiguity and reproducibility challenges, which may hamper the progress of this field. Here, we describe such challenges ahead and provide guidelines to think about strategies for shared standardized validation of experimental 4D nucleome data sets and models.
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50
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Knoch TA. A Guided Protocol for Array Based T2C: A High-Quality Selective High-Resolution High-Throughput Chromosome Interaction Capture. ACTA ACUST UNITED AC 2018; 99:e55. [PMID: 30199150 DOI: 10.1002/cphg.55] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
After now more than 170 years of research the dynamic three-dimensional chromatin architecture of genomes and the co-evolved interaction networks of regulatory elements which create genome function - i.e. the storage, expression, and finally replication of genetic information - involves ever more investigative efforts in respect to not only the pure understanding of living organisms, but also diagnosis, treatment, and even future genome engineering. To study genomic interactions, we developed a novel and superior high-quality selective high-resolution, high-throughput chromosome interaction capture method - T2C (targeted chromatin capture) - which allows to arbitrarily balance resolution, frequency range of interactions, and the investigated general genetic region or single interactions in a highly cost-effective manner in respect to the obtainable result and compared to other techniques. Beyond, T2C has such a high signal-to-noise ratio at high resolution that the "genomic" statistical mechanics level can be reached. With the guided T2C protocol described here, we were already able to finally determine the chromatin quasi-fiber conformation and its folding into stable multi-loop aggregates/rosettes connected by a linker. Actually, this guided T2C protocol provides the means for architectural genome sequencing from the level of the single base pair to the entire cell nucleus and thus to analyze genetic interactions in respect to genome function in a systems biological manner in general as well as in settings ranging from basic research, via diagnostics and treatment, to genome engineering. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Tobias A Knoch
- Biophysical Genomics, Department of Cell Biology & Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
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