1
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Hu Y, Salgado Figueroa D, Zhang Z, Veselits M, Bhattacharyya S, Kashiwagi M, Clark MR, Morgan BA, Ay F, Georgopoulos K. Lineage-specific 3D genome organization is assembled at multiple scales by IKAROS. Cell 2023; 186:5269-5289.e22. [PMID: 37995656 PMCID: PMC10895928 DOI: 10.1016/j.cell.2023.10.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 07/28/2023] [Accepted: 10/25/2023] [Indexed: 11/25/2023]
Abstract
A generic level of chromatin organization generated by the interplay between cohesin and CTCF suffices to limit promiscuous interactions between regulatory elements, but a lineage-specific chromatin assembly that supersedes these constraints is required to configure the genome to guide gene expression changes that drive faithful lineage progression. Loss-of-function approaches in B cell precursors show that IKAROS assembles interactions across megabase distances in preparation for lymphoid development. Interactions emanating from IKAROS-bound enhancers override CTCF-imposed boundaries to assemble lineage-specific regulatory units built on a backbone of smaller invariant topological domains. Gain of function in epithelial cells confirms IKAROS' ability to reconfigure chromatin architecture at multiple scales. Although the compaction of the Igκ locus required for genome editing represents a function of IKAROS unique to lymphocytes, the more general function to preconfigure the genome to support lineage-specific gene expression and suppress activation of extra-lineage genes provides a paradigm for lineage restriction.
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Affiliation(s)
- Yeguang Hu
- Cutaneous Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Daniela Salgado Figueroa
- Centers for Autoimmunity, Inflammation and Cancer Immunotherapy, La Jolla Institute for Immunology, La Jolla, CA 92037, USA; Bioinformatics and Systems Biology Program, La Jolla, CA, USA
| | - Zhihong Zhang
- Cutaneous Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Margaret Veselits
- Gwen Knapp Center for Lupus and Immunology Research, Section of Rheumatology, Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Sourya Bhattacharyya
- Centers for Autoimmunity, Inflammation and Cancer Immunotherapy, La Jolla Institute for Immunology, La Jolla, CA 92037, USA
| | - Mariko Kashiwagi
- Cutaneous Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Marcus R Clark
- Gwen Knapp Center for Lupus and Immunology Research, Section of Rheumatology, Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Bruce A Morgan
- Cutaneous Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Ferhat Ay
- Centers for Autoimmunity, Inflammation and Cancer Immunotherapy, La Jolla Institute for Immunology, La Jolla, CA 92037, USA; Bioinformatics and Systems Biology Program, La Jolla, CA, USA; Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Katia Georgopoulos
- Cutaneous Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA.
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2
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Mamidi MK, Huang J, Honjo K, Li R, Tabengwa EM, Neeli I, Randall NL, Ponnuchetty MV, Radic M, Leu CM, Davis RS. FCRL1 immunoregulation in B cell development and malignancy. Front Immunol 2023; 14:1251127. [PMID: 37822931 PMCID: PMC10562807 DOI: 10.3389/fimmu.2023.1251127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 09/01/2023] [Indexed: 10/13/2023] Open
Abstract
Immunotherapeutic targeting of surface regulatory proteins and pharmacologic inhibition of critical signaling pathways has dramatically shifted our approach to the care of individuals with B cell malignancies. This evolution in therapy reflects the central role of the B cell receptor (BCR) signaling complex and its co-receptors in the pathogenesis of B lineage leukemias and lymphomas. Members of the Fc receptor-like gene family (FCRL1-6) encode cell surface receptors with complex tyrosine-based regulation that are preferentially expressed by B cells. Among them, FCRL1 expression peaks on naïve and memory B cells and is unique in terms of its intracellular co-activation potential. Recent studies in human and mouse models indicate that FCRL1 contributes to the formation of the BCR signalosome, modulates B cell signaling, and promotes humoral responses. Progress in understanding its regulatory properties, along with evidence for its over-expression by mature B cell leukemias and lymphomas, collectively imply important yet unmet opportunities for FCRL1 in B cell development and transformation. Here we review recent advances in FCRL1 biology and highlight its emerging significance as a promising biomarker and therapeutic target in B cell lymphoproliferative disorders.
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Affiliation(s)
- Murali K. Mamidi
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jifeng Huang
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Kazuhito Honjo
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ran Li
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Edlue M. Tabengwa
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Indira Neeli
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Nar’asha L. Randall
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Manasa V. Ponnuchetty
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Marko Radic
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Chuen-Miin Leu
- Institute of Microbiology and Immunology, National Yang Ming ChiaoTung University, Taipei, Taiwan
| | - Randall S. Davis
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Departments of Microbiology, and Biochemistry & Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, United States
- O’Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, United States
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3
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Akiyama T, Yamamoto T. Regulation of Early Lymphocyte Development via mRNA Decay Catalyzed by the CCR4-NOT Complex. Front Immunol 2021; 12:715675. [PMID: 34349771 PMCID: PMC8326961 DOI: 10.3389/fimmu.2021.715675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/05/2021] [Indexed: 11/13/2022] Open
Abstract
Development of lymphocytes is precisely regulated by various mechanisms. In addition to transcriptional rates, post-transcriptional regulation of mRNA abundance contributes to differentiation of lymphocytes. mRNA decay is a post-transcriptional mechanism controlling mRNA abundance. The carbon catabolite repression 4 (CCR4)-negative on TATA-less (NOT) complex controls mRNA longevity by catalyzing mRNA deadenylation, which is the rate-limiting step in the mRNA decay pathway. mRNA decay, regulated by the CCR4-NOT complex, is required for differentiation of pro-B to pre-B cells and V(D)J recombination in pro-B cells. In this process, it is likely that the RNA-binding proteins, ZFP36 ring finger protein like 1 and 2, recruit the CCR4-NOT complex to specific target mRNAs, thereby inducing cell quiescence of pro-B cells. A recent study showed that the CCR4-NOT complex participates in positive selection of thymocytes. Mechanistically, the CCR4-NOT deadenylase complex inhibits abnormal apoptosis by reducing the expression level of mRNAs encoding pro-apoptotic proteins, which are otherwise up-regulated during positive selection. We discuss mechanisms regulating CCR4-NOT complex-dependent mRNA decay in lymphocyte development and selection.
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Affiliation(s)
- Taishin Akiyama
- Laboratory for Immune Homeostasis, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan.,Graduate School of Medical Life Science, Yokohama City University, Yokohama, Japan
| | - Tadashi Yamamoto
- Cell Signal Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
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4
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Lodewijckx I, Cools J. Deregulation of the Interleukin-7 Signaling Pathway in Lymphoid Malignancies. Pharmaceuticals (Basel) 2021; 14:443. [PMID: 34066732 DOI: 10.3390/ph14050443] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 12/21/2022] Open
Abstract
The cytokine interleukin-7 (IL-7) and its receptor are critical for lymphoid cell development. The loss of IL-7 signaling causes severe combined immunodeficiency, whereas gain-of-function alterations in the pathway contribute to malignant transformation of lymphocytes. Binding of IL-7 to the IL-7 receptor results in the activation of the JAK-STAT, PI3K-AKT and Ras-MAPK pathways, each contributing to survival, cell cycle progression, proliferation and differentiation. Here, we discuss the role of deregulated IL-7 signaling in lymphoid malignancies of B- and T-cell origin. Especially in T-cell leukemia, more specifically in T-cell acute lymphoblastic leukemia and T-cell prolymphocytic leukemia, a high frequency of mutations in components of the IL-7 signaling pathway are found, including alterations in IL7R, IL2RG, JAK1, JAK3, STAT5B, PTPN2, PTPRC and DNM2 genes.
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Abstract
The assembly of T cell receptor (TCR) and immunoglobulin (Ig) genes by V(D)J recombination generates the antigen receptor (AgR) diversity that is vital for adaptive immunity. At most AgR loci, V(D)J recombination is regulated so that only one allele assembles a functional gene, ensuring that nearly every T and B cell expresses a single type, or specificity, of AgR. The genomic organizations of some AgR loci permit the assembly and expression of two distinct genes on each allele; however, this is prevented by undetermined mechanisms. We show that the poor qualities of recombination signal sequences (RSSs) flanking Vβ gene segments suppress the assembly and expression of two distinct TCRβ genes from a single allele. Our data demonstrate that an intrinsic genetic mechanism that stochastically limits Vβ recombination efficiency governs monogenic TCRβ expression, thereby restraining the expression of multiple AgRs on αβ T cells.
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Li X, Gong L, Gu H. Regulation of immune system development and function by Cbl-mediated ubiquitination. Immunol Rev 2020; 291:123-133. [PMID: 31402498 DOI: 10.1111/imr.12789] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 05/30/2019] [Indexed: 12/24/2022]
Abstract
Ubiquitination is a form of posttranslational protein modification that affects the activity of target proteins by regulating their intracellular degradation, trafficking, localization, and association with other regulators. Recent studies have placed protein ubiquitination as an important regulatory mode to control immune system development, function, and pathogenesis. In this review, we will mainly update the research progress from our laboratory on the roles of the Cbl family of E3 ubiquitin ligases in the development and function of lymphocytes and non-lymphoid cells. In addition, we will highlight our current understanding of the mechanisms used by this family of proteins, especially Cbl and Cbl-b, to co-ordinately regulate the function of various receptors and transcription factors in the context of immune regulation and diseases.
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Affiliation(s)
- Xin Li
- Kisoji Biotechnologies, Laval, Quebec, Canada
| | - Liying Gong
- Institut de Recherches Cliniques de Montreàl, Montreal, Quebec, Canada.,Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
| | - Hua Gu
- Institut de Recherches Cliniques de Montreàl, Montreal, Quebec, Canada.,Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada.,Department of Microbiology and Immunology, Department of Biochemistry and Molecular Medicine, University of Montreal, Montreal, Quebec, Canada
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7
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Honjo K, Won WJ, King RG, Ianov L, Crossman DK, Easlick JL, Shakhmatov MA, Khass M, Vale AM, Stephan RP, Li R, Davis RS. Fc Receptor-Like 6 (FCRL6) Discloses Progenitor B Cell Heterogeneity That Correlates With Pre-BCR Dependent and Independent Pathways of Natural Antibody Selection. Front Immunol 2020; 11:82. [PMID: 32117244 PMCID: PMC7033751 DOI: 10.3389/fimmu.2020.00082] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 01/13/2020] [Indexed: 11/24/2022] Open
Abstract
B-1a cells produce "natural" antibodies (Abs) to neutralize pathogens and clear neo self-antigens, but the fundamental selection mechanisms that shape their polyreactive repertoires are poorly understood. Here, we identified a B cell progenitor subset defined by Fc receptor-like 6 (FCRL6) expression, harboring innate-like defense, migration, and differentiation properties conducive for natural Ab generation. Compared to FCRL6- pro B cells, the repressed mitotic, DNA damage repair, and signaling activity of FCRL6+ progenitors, yielded VH repertoires with biased distal Ighv segment accessibility, constrained diversity, and hydrophobic and charged CDR-H3 sequences. Beyond nascent autoreactivity, VH11 productivity, which predominates phosphatidylcholine-specific B-1a B cell receptors (BCRs), was higher for FCRL6+ cells as was pre-BCR formation, which was required for Myc induction and VH11, but not VH12, B-1a development. Thus, FCRL6 revealed unexpected heterogeneity in the developmental origins, regulation, and selection of natural Abs at the pre-BCR checkpoint with implications for autoimmunity and lymphoproliferative disorders.
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MESH Headings
- Animals
- Antibodies/immunology
- Antibodies/metabolism
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Female
- Humans
- Immunoglobulin Heavy Chains/genetics
- Immunoglobulin Heavy Chains/immunology
- Immunoglobulin Variable Region/genetics
- Immunoglobulin Variable Region/immunology
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- Phosphatidylcholines/immunology
- Phosphatidylcholines/metabolism
- Precursor Cells, B-Lymphoid/immunology
- Precursor Cells, B-Lymphoid/metabolism
- Receptors, Antigen, B-Cell/genetics
- Receptors, Antigen, B-Cell/immunology
- Receptors, Antigen, B-Cell/metabolism
- Receptors, Fc/genetics
- Receptors, Fc/immunology
- Receptors, Fc/metabolism
- Signal Transduction/genetics
- Signal Transduction/immunology
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Affiliation(s)
- Kazuhito Honjo
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Woong-Jai Won
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Rodney G. King
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Lara Ianov
- Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - David K. Crossman
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Juliet L. Easlick
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Mikhail A. Shakhmatov
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Mohamed Khass
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Genetic Engineering and Biotechnology Division, National Research Center, Cairo, Egypt
| | - Andre M. Vale
- Program in Immunobiology, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Robert P. Stephan
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ran Li
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Randall S. Davis
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, United States
- Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, United States
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8
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Zhong C, Zheng M, Cui K, Martins AJ, Hu G, Li D, Tessarollo L, Kozlov S, Keller JR, Tsang JS, Zhao K, Zhu J. Differential Expression of the Transcription Factor GATA3 Specifies Lineage and Functions of Innate Lymphoid Cells. Immunity 2019; 52:83-95.e4. [PMID: 31882362 DOI: 10.1016/j.immuni.2019.12.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 09/18/2019] [Accepted: 12/03/2019] [Indexed: 01/06/2023]
Abstract
Lymphoid tissue inducer (LTi) cells are regarded as a subset of innate lymphoid cells (ILCs). However, these cells are not derived from the ILC common progenitor, which generates other ILC subsets and is defined by the expression of the transcription factor PLZF. Here, we examined transcription factor(s) determining the fate of LTi progenitors versus non-LTi ILC progenitors. Conditional deletion of Gata3 resulted in the loss of PLZF+ non-LTi progenitors but not the LTi progenitors that expressed the transcription factor RORγt. Consistently, PLZF+ non-LTi progenitors expressed high amounts of GATA3, whereas GATA3 expression was low in RORγt+ LTi progenitors. The generation of both progenitors required the transcriptional regulator Id2, which defines the common helper-like innate lymphoid progenitor (ChILP), but not cytokine signaling. Nevertheless, low GATA3 expression was necessary for the generation of functionally mature LTi cells. Thus, differential expression of GATA3 determines the fates and functions of distinct ILC progenitors.
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Affiliation(s)
- Chao Zhong
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Institute of Systems Biomedicine, Department of Immunology, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing 100191, PRC.
| | - Mingzhu Zheng
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kairong Cui
- Laboratory of Epigenome Biology, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Andrew J Martins
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Gangqing Hu
- Laboratory of Epigenome Biology, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA; Department of Microbiology, Immunology, and Cell Biology, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
| | - Dan Li
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, PRC; Department of Clinical Laboratory, the Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, PRC
| | - Lino Tessarollo
- Mouse Cancer Genetics Program, Center for Cancer Research, NCI, Frederick, MD 21702, USA
| | - Serguei Kozlov
- Center for Advanced Preclinical Research, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Jonathan R Keller
- Mouse Cancer Genetics Program, Center for Cancer Research, NCI, Frederick, MD 21702, USA; Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - John S Tsang
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Keji Zhao
- Laboratory of Epigenome Biology, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jinfang Zhu
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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9
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Pokrovskii M, Hall JA, Ochayon DE, Yi R, Chaimowitz NS, Seelamneni H, Carriero N, Watters A, Waggoner SN, Littman DR, Bonneau R, Miraldi ER. Characterization of Transcriptional Regulatory Networks that Promote and Restrict Identities and Functions of Intestinal Innate Lymphoid Cells. Immunity 2019; 51:185-197.e6. [PMID: 31278058 PMCID: PMC6863506 DOI: 10.1016/j.immuni.2019.06.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 03/12/2019] [Accepted: 06/04/2019] [Indexed: 12/14/2022]
Abstract
Innate lymphoid cells (ILCs) promote tissue homeostasis and immune defense but also contribute to inflammatory diseases. ILCs exhibit phenotypic and functional plasticity in response to environmental stimuli, yet the transcriptional regulatory networks (TRNs) that control ILC function are largely unknown. Here, we integrate gene expression and chromatin accessibility data to infer regulatory interactions between transcription factors (TFs) and genes within intestinal type 1, 2, and 3 ILC subsets. We predicted the "core" TFs driving ILC identities, organized TFs into cooperative modules controlling distinct gene programs, and validated roles for c-MAF and BCL6 as regulators affecting type 1 and type 3 ILC lineages. The ILC network revealed alternative-lineage-gene repression, a mechanism that may contribute to reported plasticity between ILC subsets. By connecting TFs to genes, the TRNs suggest means to selectively regulate ILC effector functions, while our network approach is broadly applicable to identifying regulators in other in vivo cell populations.
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Affiliation(s)
- Maria Pokrovskii
- The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY 10016, USA
| | - Jason A Hall
- The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY 10016, USA
| | - David E Ochayon
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Ren Yi
- Departments of Biology and Computer Science, New York University, NY 10003, USA
| | - Natalia S Chaimowitz
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Harsha Seelamneni
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Nicholas Carriero
- Center for Computational Biology, Flatiron Institute, New York, NY 10010, USA
| | - Aaron Watters
- Center for Computational Biology, Flatiron Institute, New York, NY 10010, USA
| | - Stephen N Waggoner
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Dan R Littman
- The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute.
| | - Richard Bonneau
- Departments of Biology and Computer Science, New York University, NY 10003, USA; Center for Computational Biology, Flatiron Institute, New York, NY 10010, USA.
| | - Emily R Miraldi
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA; Divisions of Immunobiology and Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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10
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Ng KK, Yui MA, Mehta A, Siu S, Irwin B, Pease S, Hirose S, Elowitz MB, Rothenberg EV, Kueh HY. A stochastic epigenetic switch controls the dynamics of T-cell lineage commitment. eLife 2018; 7:37851. [PMID: 30457103 PMCID: PMC6245732 DOI: 10.7554/elife.37851] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 10/11/2018] [Indexed: 12/30/2022] Open
Abstract
Cell fate decisions occur through the switch-like, irreversible activation of fate-specifying genes. These activation events are often assumed to be tightly coupled to changes in upstream transcription factors, but could also be constrained by cis-epigenetic mechanisms at individual gene loci. Here, we studied the activation of Bcl11b, which controls T-cell fate commitment. To disentangle cis and trans effects, we generated mice where two Bcl11b copies are tagged with distinguishable fluorescent proteins. Quantitative live microscopy of progenitors from these mice revealed that Bcl11b turned on after a stochastic delay averaging multiple days, which varied not only between cells but also between Bcl11b alleles within the same cell. Genetic perturbations, together with mathematical modeling, showed that a distal enhancer controls the rate of epigenetic activation, while a parallel Notch-dependent trans-acting step stimulates expression from activated loci. These results show that developmental fate transitions can be controlled by stochastic cis-acting events on individual loci.
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Affiliation(s)
- Kenneth Kh Ng
- Department of Bioengineering, University of Washington, Seattle, United States.,Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Mary A Yui
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Arnav Mehta
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | | | - Blythe Irwin
- Department of Bioengineering, University of Washington, Seattle, United States
| | - Shirley Pease
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Satoshi Hirose
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Michael B Elowitz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States.,Department of Applied Physics, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, United States
| | - Ellen V Rothenberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Hao Yuan Kueh
- Department of Bioengineering, University of Washington, Seattle, United States.,Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
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11
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Ward A, Kumari G, Sen R, Desiderio S. The RAG-2 Inhibitory Domain Gates Accessibility of the V(D)J Recombinase to Chromatin. Mol Cell Biol 2018; 38:e00159-18. [PMID: 29760281 DOI: 10.1128/MCB.00159-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 05/01/2018] [Indexed: 02/06/2023] Open
Abstract
Accessibility of antigen receptor loci to RAG is correlated with the presence of H3K4me3, which binds to a plant homeodomain (PHD) in the RAG-2 subunit and promotes V(D)J recombination. A point mutation in the PHD, W453A, eliminates binding of H3K4me3 and impairs recombination. The debilitating effect of the W453A mutation is ameliorated by second-site mutations that locate an inhibitory domain in the interval from residues 352 through 405 of RAG-2. Disruption of the inhibitory domain stimulates V(D)J recombination within extrachromosomal substrates and at endogenous antigen receptor loci. Association of RAG-1 and RAG-2 with chromatin at the IgH locus in B cell progenitors is dependent on recognition of H3K4me3 by the PHD. Strikingly, disruption of the inhibitory domain permits association of RAG with the IgH locus in the absence of H3K4me3 binding. Thus, the inhibitory domain acts as a gate that prohibits RAG from accessing the IgH locus unless RAG-2 is engaged by H3K4me3.
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12
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Olivares-Villagómez D, Van Kaer L. Intestinal Intraepithelial Lymphocytes: Sentinels of the Mucosal Barrier. Trends Immunol 2018; 39:264-275. [PMID: 29221933 PMCID: PMC8056148 DOI: 10.1016/j.it.2017.11.003] [Citation(s) in RCA: 146] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 11/14/2017] [Accepted: 11/15/2017] [Indexed: 02/06/2023]
Abstract
Intestinal intraepithelial lymphocytes (IELs) are a large and diverse population of lymphoid cells that reside between the intestinal epithelial cells (IECs) that form the intestinal mucosal barrier. Although IEL biology has traditionally focused on T cells, recent studies have identified several subsets of T cell receptor (TCR)-negative IELs with intriguing properties. New insight into the development, homeostasis, and functions of distinct IEL subsets has recently been provided. Additional studies have revealed intricate interactions between different IEL subsets, reciprocal interactions between IELs and IECs, and communication of IELs with immune cells that reside outside the intestinal epithelium. We review here sentinel functions of IELs in the maintenance of the mucosal barrier integrity, as well as how dysregulated IEL responses can contribute to pathology.
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Affiliation(s)
- Danyvid Olivares-Villagómez
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA.
| | - Luc Van Kaer
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA.
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13
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Bonnet M, Sarmento LM, Martins AC, Sobral D, Silva J, Demengeot J. iRAGu: A Novel Inducible and Reversible Mouse Model for Ubiquitous Recombinase Activity. Front Immunol 2017; 8:1525. [PMID: 29176980 PMCID: PMC5686385 DOI: 10.3389/fimmu.2017.01525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Accepted: 10/27/2017] [Indexed: 11/17/2022] Open
Abstract
Developing lymphocytes express the recombination activating genes (RAGs) 1 and 2 products that form a site specific recombinase complex (RAG), introducing double strand DNA breaks (DSBs) at recombination signal sequences (RSSs) flanking the V, D, and J gene segments in the antigen receptor loci. The subsequent steps in the reaction consist in the ligation of DSBs by ubiquitous enzymes of the non-homologous end joining DNA repair pathway. This mutagenesis process is responsible for the generation of the very large clonal diversity of T and B lymphocytes, itself allowing the recognition of a virtually open-ended antigenic universe. Sequences resembling RSS are found at high frequency all over the genome, and involved in RAG mediated illegitimate recombination and translocations. Hence, natural and induced ectopic activity of RAG is a threat to the genome only recently underscored. Here, we report and characterize a novel mouse transgenic system for which ubiquitous expression of the recombinase is inducible. In this system, the RAG1 protein is constitutively expressed and functional, while the RAG2 protein, coupled to the estrogen receptor, becomes functionally active upon 4-hydroxytamoxifen (TAM) administration. We describe two transgenic lines. The first one, when introgressed into an endogenous Rag2−/− genetic background is faithfully recapitulating lymphocyte development, repertoire dynamics and cryptic rearrangements, in a TAM-dependent manner. In this model, deprivation of TAM is followed by lymphocyte development arrest, evidencing the reversibility of the system. The second transgenic line is leaky, as the transgenes promote lymphocyte differentiation in absence of TAM treatment. Upon TAM-induction defects in lymphocytes composition and global health reveals the deleterious effect of uncontrolled RAG activity. Overall, this novel transgenic model provides a tool where RAG activity can be specifically manipulated to assess the dynamics of lymphocyte differentiation and the challenges imposed by the recombinase on the vertebrate genome.
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Affiliation(s)
- Marie Bonnet
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | | | | | | | - Joana Silva
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
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14
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Rodgers KK. Riches in RAGs: Revealing the V(D)J Recombinase through High-Resolution Structures. Trends Biochem Sci 2016; 42:72-84. [PMID: 27825771 DOI: 10.1016/j.tibs.2016.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/04/2016] [Accepted: 10/17/2016] [Indexed: 12/15/2022]
Abstract
Development of the adaptive immune system is dependent on V(D)J recombination, which forms functional antigen receptor genes through rearrangement of component gene segments. The V(D)J recombinase, comprising recombination-activating proteins RAG1 and RAG2, guides the initial DNA cleavage events to the recombination signal sequence (RSS), which flanks each gene segment. Although the enzymatic steps for RAG-mediated endonucleolytic activity were established over two decades ago, only recently have high-resolution structural studies of the catalytically active core regions of the RAG proteins shed light on conformational requirements for the reaction. While outstanding questions remain, we have a clearer picture of how RAG proteins function in generating the diverse repertoires of antigen receptors, the underlying foundation of the adaptive immune system.
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Affiliation(s)
- Karla K Rodgers
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190, USA.
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15
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Abstract
Effective immune responses require the precise regulation of dynamic interactions between hematopoietic and non-hematopoietic cells. The Rho subfamily of GTPases, which includes RhoA, is rapidly activated downstream of a diverse array of biochemical and biomechanical signals, and is emerging as an important mediator of this cross-talk. Key downstream effectors of RhoA are the Rho kinases, or ROCKs. The ROCKs are two serine-threonine kinases that can act as global coordinators of a tissue’s response to stress and injury because of their ability to regulate a wide range of biological processes. Although the RhoA-ROCK pathway has been extensively investigated in the non-hematopoietic compartment, its role in the immune system is just now becoming appreciated. In this commentary, we provide a brief overview of recent findings that highlight the contribution of this pathway to lymphocyte development and activation, and the impact that dysregulation in the activation of RhoA and/or the ROCKs may exert on a growing list of autoimmune and lymphoproliferative disorders.
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Affiliation(s)
- Edd Ricker
- Autoimmunity and Inflammation Program, Hospital for Special Surgery, New York, New York, 10021, USA; Graduate Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, New York, 10065, USA
| | - Luvana Chowdhury
- Autoimmunity and Inflammation Program, Hospital for Special Surgery, New York, New York, 10021, USA
| | - Woelsung Yi
- Autoimmunity and Inflammation Program, Hospital for Special Surgery, New York, New York, 10021, USA; David Z. Rosensweig Genomics Research Center, Hospital for Special Surgery, New York, New York, 10021, USA
| | - Alessandra B Pernis
- Autoimmunity and Inflammation Program, Hospital for Special Surgery, New York, New York, 10021, USA; Graduate Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, New York, 10065, USA; David Z. Rosensweig Genomics Research Center, Hospital for Special Surgery, New York, New York, 10021, USA; Department of Medicine, Weill Cornell Medical College, New York, New York, 10021, USA
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16
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Siggs OM, Stockenhuber A, Deobagkar-Lele M, Bull KR, Crockford TL, Kingston BL, Crawford G, Anzilotti C, Steeples V, Ghaffari S, Czibik G, Bellahcene M, Watkins H, Ashrafian H, Davies B, Woods A, Carling D, Yavari A, Beutler B, Cornall RJ. Mutation of Fnip1 is associated with B-cell deficiency, cardiomyopathy, and elevated AMPK activity. Proc Natl Acad Sci U S A 2016; 113:E3706-15. [PMID: 27303042 DOI: 10.1073/pnas.1607592113] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Folliculin (FLCN) is a tumor-suppressor protein mutated in the Birt-Hogg-Dubé (BHD) syndrome, which associates with two paralogous proteins, folliculin-interacting protein (FNIP)1 and FNIP2, forming a complex that interacts with the AMP-activated protein kinase (AMPK). Although it is clear that this complex influences AMPK and other metabolic regulators, reports of its effects have been inconsistent. To address this issue, we created a recessive loss-of-function variant of Fnip1 Homozygous FNIP1 deficiency resulted in profound B-cell deficiency, partially restored by overexpression of the antiapoptotic protein BCL2, whereas heterozygous deficiency caused a loss of marginal zone B cells. FNIP1-deficient mice developed cardiomyopathy characterized by left ventricular hypertrophy and glycogen accumulation, with close parallels to mice and humans bearing gain-of-function mutations in the γ2 subunit of AMPK. Concordantly, γ2-specific AMPK activity was elevated in neonatal FNIP1-deficient myocardium, whereas AMPK-dependent unc-51-like autophagy activating kinase 1 (ULK1) phosphorylation and autophagy were increased in FNIP1-deficient B-cell progenitors. These data support a role for FNIP1 as a negative regulator of AMPK.
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17
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Arenzana TL, Schjerven H, Smale ST. Regulation of gene expression dynamics during developmental transitions by the Ikaros transcription factor. Genes Dev 2015; 29:1801-16. [PMID: 26314708 PMCID: PMC4573854 DOI: 10.1101/gad.266999.115] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Accepted: 07/31/2015] [Indexed: 12/01/2022]
Abstract
In this study, Arenzana et al. perform a detailed analysis of the functional abnormalities at five sequential stages of thymocyte development in an Ikaros mutant mouse strain followed by RNA-seq to document the gene expression changes seen in the mutant cells. By combining the quantitative power of the RNA-seq method with the analysis of five sequential stages of development, the findings demonstrate a unique function for Ikaros in supporting dynamic changes in gene expression during developmental transitions. The DNA-binding protein Ikaros is a potent tumor suppressor and hematopoietic regulator. However, the mechanisms by which Ikaros functions remain poorly understood, due in part to its atypical DNA-binding properties and partnership with the poorly understood Mi-2/NuRD complex. In this study, we analyzed five sequential stages of thymocyte development in a mouse strain containing a targeted deletion of Ikaros zinc finger 4, which exhibits a select subset of abnormalities observed in Ikaros-null mice. By examining thymopoiesis in vivo and in vitro, diverse abnormalities were observed at each developmental stage. RNA sequencing revealed that each stage is characterized by the misregulation of a limited number of genes, with a strong preference for stage-specific rather than lineage-specific genes. Strikingly, individual genes rarely exhibited Ikaros dependence at all stages. Instead, a consistent feature of the aberrantly expressed genes was a reduced magnitude of expression level change during developmental transitions. These results, combined with analyses of the interplay between Ikaros loss of function and Notch signaling, suggest that Ikaros may not be a conventional activator or repressor of defined sets of genes. Instead, a primary function may be to sharpen the dynamic range of gene expression changes during developmental transitions via atypical molecular mechanisms that remain undefined.
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Affiliation(s)
- Teresita L Arenzana
- Department of Microbiology, Immunology, and Molecular Genetics, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Hilde Schjerven
- Department of Laboratory Medicine, University of California at San Francisco, San Francisco, California 94143, USA
| | - Stephen T Smale
- Department of Microbiology, Immunology, and Molecular Genetics, University of California at Los Angeles, Los Angeles, California 90095, USA
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18
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Abstract
INTRODUCTION OR BACKGROUND The V(D)J recombination is a DNA rearrangement process that generates the diversity of T and B lymphocyte immune repertoire. It proceeds through the generation of a DNA double-strand break (DNA-DSB) by the Rag1/2 lymphoid-specific factors, which is repaired by the non-homologous end joining (NHEJ) DNA repair pathway. V(D)J recombination also constitutes a checkpoint in the lymphoid development. SOURCES OF DATA V(D)J recombination defect results in severe combined immune deficiency (SCID) with a lack of T and B lymphocytes. AREAS OF AGREEMENT The V(D)J recombination represents one of the few programmed molecular events leading to DNA-DSBs that strictly relies on NHEJ. Two NHEJ factors, Artemis and XLF/Cernunnos, were identified through the molecular studies of SCID patients. Mutations in PRKDC and DNA Ligase IV genes also result in SCID. GROWING POINTS Studies in mice have demonstrated that XLF/Cernunnos is dispensable for V(D)J recombination in lymphoid cells but not for the repair of genotoxic-induced DNA-DSBs, which raises the question of the implication of Rag1/2 factors in the DNA repair phase of V(D)J recombination. AREAS TIMELY FOR DEVELOPING RESEARCH New factors of NHEJ, such as PAXX, are being identified. Patients with NHEJ deficiency (XRCC4) without immune deficiency were recently reported. We, therefore, may not have yet the complete picture of DNA-DSB repair in the context of V(D)J recombination.
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Affiliation(s)
- Jean-Pierre de Villartay
- Laboratory of Genome Dynamics in the Immune System, INSERM UMR1163, Université Paris Descartes Sorbonne Paris Cité, Institut Imagine, Paris, France
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19
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Constantinides MG, Gudjonson H, McDonald BD, Ishizuka IE, Verhoef PA, Dinner AR, Bendelac A. PLZF expression maps the early stages of ILC1 lineage development. Proc Natl Acad Sci U S A 2015; 112:5123-8. [PMID: 25838284 DOI: 10.1073/pnas.1423244112] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Among the variety of tissue-resident NK-like populations recently distinguished from recirculating classical NK (cNK) cells, liver innate lymphoid cells (ILC) type 1 (ILC1s) have been shown to represent a distinct lineage that originates from a novel promyelocytic leukaemia zinc finger (PLZF)-expressing ILC precursor (ILCP) strictly committed to the ILC1, ILC2, and ILC3 lineages. Here, using PLZF-reporter mice and cell transfer assays, we studied the developmental progression of ILC1s and demonstrated substantial overlap with stages previously ascribed to the cNK lineage, including pre-pro-NK, pre-NK precursor (pre-NKP), refined NKP (rNKP), and immature NK (iNK). Although they originated from different precursors, the ILC1 and cNK lineages followed a parallel progression at early stages and diverged later at the iNK stage, with a striking predominance of ILC1s over cNKs early in ontogeny. Although a limited set of ILC1 genes depended on PLZF for expression, characteristically including Il7r, most of these genes were also differentially expressed between ILC1s and cNKs, indicating that PLZF together with other, yet to be defined, factors contribute to the divergence between these lineages.
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20
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Sun A, Novobrantseva TI, Coffre M, Hewitt SL, Jensen K, Skok JA, Rajewsky K, Koralov SB. VH replacement in primary immunoglobulin repertoire diversification. Proc Natl Acad Sci U S A 2015; 112:E458-66. [PMID: 25609670 DOI: 10.1073/pnas.1418001112] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The genes encoding the variable (V) region of the B-cell antigen receptor (BCR) are assembled from V, D (diversity), and J (joining) elements through a RAG-mediated recombination process that relies on the recognition of recombination signal sequences (RSSs) flanking the individual elements. Secondary V(D)J rearrangement modifies the original Ig rearrangement if a nonproductive original joint is formed, as a response to inappropriate signaling from a self-reactive BCR, or as part of a stochastic mechanism to further diversify the Ig repertoire. VH replacement represents a RAG-mediated secondary rearrangement in which an upstream VH element recombines with a rearranged VHDHJH joint to generate a new BCR specificity. The rearrangement occurs between the cryptic RSS of the original VH element and the conventional RSS of the invading VH gene, leaving behind a footprint of up to five base pairs (bps) of the original VH gene that is often further obscured by exonuclease activity and N-nucleotide addition. We have previously demonstrated that VH replacement can efficiently rescue the development of B cells that have acquired two nonproductive heavy chain (IgH) rearrangements. Here we describe a novel knock-in mouse model in which the prerearranged IgH locus resembles an endogenously rearranged productive VHDHJH allele. Using this mouse model, we characterized the role of VH replacement in the diversification of the primary Ig repertoire through the modification of productive VHDHJH rearrangements. Our results indicate that VH replacement occurs before Ig light chain rearrangement and thus is not involved in the editing of self-reactive antibodies.
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21
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Prabhu SB, Khalsa JK, Banerjee H, Das A, Srivastava S, Mattoo HR, Thyagarajan K, Tanwar S, Das DS, Majumdar SS, George A, Bal V, Durdik JM, Rath S. Role of apoptosis-inducing factor (Aif) in the T cell lineage. Indian J Med Res 2013; 138:577-90. [PMID: 24434313 PMCID: PMC3928691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Multiple checkpoints regulating finely balanced death-versus-survival decisions characterize both thymic development and peripheral homeostasis of T lymphocytes. While exploring the mechanisms of T cell death involved at various stages during the life of a T cell, we have observed and reported a variety of non-redundant roles for apoptosis inducing factor (Aif), a mitochondrial flavoprotein. Aif is ubiquitously expressed in all cell lineages and functions as an NADH oxidase in its mitochondrial location. It is released following the mitochondrial death signals, whereupon it translocates to the nucleus, binds to DNA and causes large-scale DNA fragmentation. During T cell development, Aif is important for developing thymocytes to navigate the double negative (DN)3 to DN4 transition (beta-selection), via its oxidoreductase property which protects the rapidly proliferating cells from death due to reactive oxygen species (ROS). In peripheral mature T cells, Aif deficiency leads to an increased susceptibility of T cell blasts to activation induced cell death (AICD), possibly mediated by its antioxidant function, and decreased sensitivity to neglect-induced death (NID). Thus, Aif seems to have pro-apoptotic and anti-apoptotic roles in the same lineage in different contexts and at different stages. Surprisingly, in the closely related B lymphocyte lineage, Aif deficiency does not result in any abnormality. These findings generate the possibility of specific T cell dysfunction in human disease caused by Aif deficiency, as well as in mitochondriopathies due to other causes. Also, these data raise questions regarding the basis of lineage-specific consequences of the dysfunction/deficiency of apparently ubiquitous molecules.
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Affiliation(s)
- Savit B. Prabhu
- National Institute of Immunology, New Delhi, India,Reprint requests: Dr Savit B. Prabhu / Dr Satyajit Rath, National Institute of Immunology, Aruna Asaf Ali Road, New Delhi 110 067, India e-mail: /
| | | | - Hridesh Banerjee
- National Institute of Immunology, New Delhi, India,Laboratory of Molecular Biology & Immunology, National Institute of Aging, 251 Bayview Boulevard, Baltimore MD 21224, USA
| | - Abhishek Das
- National Institute of Immunology, New Delhi, India,Immune Disease Institute, Children's Hospital Boston, 3 Blackfan Circle, Boston MA 02115, USA
| | - Smita Srivastava
- National Institute of Immunology, New Delhi, India,Division of Infectious Diseases, Department of Medicine, New York University School of Medicine, Smilow 901, 550 First Avenue, New York NY 10016, USA
| | - Hamid R. Mattoo
- National Institute of Immunology, New Delhi, India,MGH Cancer Center, Building 149, 13th Street, Charlestown, MA 02129, USA
| | - Krishnamurthy Thyagarajan
- National Institute of Immunology, New Delhi, India,Department of Surgery, Medical University of South Carolina, 86 Jonathan Lucas Street, Charleston SC 29425, USA
| | | | | | | | - Anna George
- National Institute of Immunology, New Delhi, India
| | - Vineeta Bal
- National Institute of Immunology, New Delhi, India
| | - Jeannine M. Durdik
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
| | - Satyajit Rath
- National Institute of Immunology, New Delhi, India,Reprint requests: Dr Savit B. Prabhu / Dr Satyajit Rath, National Institute of Immunology, Aruna Asaf Ali Road, New Delhi 110 067, India e-mail: /
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22
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Lorenzo LPE, Shatynski KE, Clark S, Yarowsky PJ, Williams MS. Defective thymic progenitor development and mature T-cell responses in a mouse model for Down syndrome. Immunology 2013; 139:447-58. [PMID: 23432468 DOI: 10.1111/imm.12092] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 02/07/2013] [Accepted: 02/13/2013] [Indexed: 12/26/2022] Open
Abstract
In addition to archetypal cognitive defects, Down syndrome (DS) is characterized by altered lymphocyte development and function, including premature thymic involution and increased incidence of infections. However, the potential mechanisms for these changes have not been fully elucidated. The current study used the Ts65Dn mouse model of DS to assess deficiencies in T-cell development and possible molecular alterations. Ts65Dn mice exhibited premature thymic involution and a threefold to fourfold decrease in the number and proportion of immature, double-negative thymocyte progenitors. In addition, there were twofold fewer double-positive and CD4 single-positive thymocytes in Ts65Dn thymuses. Reflecting this deficient thymic function, there were fewer naive T cells in the spleen and polyclonal stimulation of peripheral T cells exhibited a marked reduction in proliferation, suggesting a senescent phenotype. In contrast, B-cell progenitors were unchanged in the bone marrow of Ts65Dn mice, but in the spleen, there were decreased transitional and follicular B cells and these cells proliferated less upon antigen receptor stimulus but not in response to lipopolysaccharide. As a potential mechanism for diminished thymic function, immature thymocyte populations expressed diminished levels of the cytokine receptor interleukin-7Rα, which was associated with decreased proliferation and increased apoptosis. Increased oxidative stress and inhibition of the Notch pathway were identified as possible mediators of decreased interleukin-7Rα expression in Ts65Dn mice. The data suggest that immature thymocyte defects underlie immune dysfunction in DS and that increased oxidative stress and reduced cytokine signalling may alter lymphocyte development in Ts65Dn mice.
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Affiliation(s)
- Laureanne P E Lorenzo
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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23
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Giallourakis CC, Franklin A, Guo C, Cheng HL, Yoon HS, Gallagher M, Perlot T, Andzelm M, Murphy AJ, Macdonald LE, Yancopoulos GD, Alt FW. Elements between the IgH variable (V) and diversity (D) clusters influence antisense transcription and lineage-specific V(D)J recombination. Proc Natl Acad Sci U S A 2010; 107:22207-12. [PMID: 21123744 PMCID: PMC3009784 DOI: 10.1073/pnas.1015954107] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ig and T-cell receptor (TCR) variable-region gene exons are assembled from component variable (V), diversity (D) and joining (J) gene segments during early B and T cell development. The RAG1/2 endonuclease initiates V(D)J recombination by introducing DNA double-strand breaks at borders of the germ-line segments. In mice, the Ig heavy-chain (IgH) locus contains, from 5' to 3', several hundred V(H) gene segments, 13 D segments, and 4 J(H) segments within a several megabase region. In developing B cells, IgH variable-region exon assembly is ordered with D to J(H) rearrangement occurring on both alleles before appendage of a V(H) segment. Also, IgH V(H) to DJ(H) rearrangement does not occur in T cells, even though DJ(H) rearrangements occur at low levels. In these contexts, V(D)J recombination is controlled by modulating substrate gene segment accessibility to RAG1/2 activity. To elucidate control elements, we deleted the 100-kb intergenic region that separates the V(H) and D clusters (generating ΔV(H)-D alleles). In both B and T cells, ΔV(H)-D alleles initiated high-level antisense and, at lower levels, sense transcription from within the downstream D cluster, with antisense transcripts extending into proximal V(H) segments. In developing T lymphocytes, activated germ-line antisense transcription was accompanied by markedly increased IgH D-to-J(H) rearrangement and substantial V(H) to DJ(H) rearrangement of proximal IgH V(H) segments. Thus, the V(H)-D intergenic region, and likely elements within it, can influence silencing of sense and antisense germ-line transcription from the IgH D cluster and thereby influence targeting of V(D)J recombination.
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Affiliation(s)
- Cosmas C. Giallourakis
- The Howard Hughes Medical Institute, Children's Hospital, Immune Disease Institute and Department of Genetics, Harvard Medical School, Boston, MA 02115
- Gastrointestinal Unit, Massachusetts General Hospital, Boston, MA 02114; and
| | - Andrew Franklin
- The Howard Hughes Medical Institute, Children's Hospital, Immune Disease Institute and Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Chunguang Guo
- The Howard Hughes Medical Institute, Children's Hospital, Immune Disease Institute and Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Hwei-Ling Cheng
- The Howard Hughes Medical Institute, Children's Hospital, Immune Disease Institute and Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Hye Suk Yoon
- The Howard Hughes Medical Institute, Children's Hospital, Immune Disease Institute and Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Michael Gallagher
- The Howard Hughes Medical Institute, Children's Hospital, Immune Disease Institute and Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Thomas Perlot
- The Howard Hughes Medical Institute, Children's Hospital, Immune Disease Institute and Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Milena Andzelm
- The Howard Hughes Medical Institute, Children's Hospital, Immune Disease Institute and Department of Genetics, Harvard Medical School, Boston, MA 02115
| | | | | | | | - Frederick W. Alt
- The Howard Hughes Medical Institute, Children's Hospital, Immune Disease Institute and Department of Genetics, Harvard Medical School, Boston, MA 02115
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24
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Abstract
Many aspects of gene function are coordinated by changes in the epigenome, which include dynamic revisions of chromatin modifications, genome packaging, subnuclear localization, and chromosome conformation. All of these mechanisms are used by developing lymphocytes to regulate the assembly of functional antigen receptor genes by V(D)J recombination. This somatic rearrangement of the genome must be tightly regulated to ensure proper B and T cell development and to avoid chromosomal translocations that cause lymphoid tumors. V(D)J recombination is controlled by a complex interplay between cis-acting regulatory elements that use transcription factors as liaisons to communicate with epigenetic pathways. Genetic-epigenetic crosstalk is a key strategy employed by precursor lymphocytes to modulate chromatin configurations at Ig and Tcr loci and thereby permit or deny access to a single V(D)J recombinase complex. This article describes our current knowledge of how genetic elements orchestrate crosstalk with epigenetic mechanisms to regulate recombinase accessibility via localized, regional, or long-range changes in chromatin.
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Affiliation(s)
- Oleg Osipovich
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Eugene M. Oltz
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
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25
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Minato N. Rap signaling in normal lymphocyte development and leukemia genesis. Immune Netw 2010; 9:35-40. [PMID: 20107541 PMCID: PMC2803306 DOI: 10.4110/in.2009.9.2.35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 03/18/2009] [Indexed: 12/03/2022] Open
Abstract
Although Rap GTPases of the Ras family remained enigmatic for years, extensive studies in this decade have revealed diverse functions of Rap signaling in the control of cell proliferation, differentiation, survival, adhesion, and movement. With the use of gene-engineered mice, we have uncovered essential roles of endogenous Rap signaling in normal lymphocyte development of both T- and B-lineage cells. Deregulation of Rap signaling, on the other hand, results in the development of characteristic leukemia in manners highly dependent on the contexts of cell lineages. These results highlight crucial roles of Rap signaling in the physiology and pathology of lymphocyte development.
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Affiliation(s)
- Nagahiro Minato
- Department of Immunology and Cell Biology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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26
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Abstract
B-lymphocyte development involves sequential DNA rearrangements of immunoglobulin (Ig) heavy (mu) and light (kappa, lambda) chain loci and is dependent on transient expression of mu containing pre-antigen receptor complexes (pre-BCR). To date, genetic analysis has not identified transcription factors that coordinate the pre-B-to-B transition. We demonstrate that the related interferon regulatory factors IRF-4 (Pip) and IRF-8 (ICSBP) are required for Ig light but not heavy-chain gene rearrangement. In the absence of these transcription factors, B-cell development is arrested at the cycling pre-B-cell stage and the mutant cells fail to down-regulate the pre-BCR. On the basis of molecular analysis, we propose that IRF-4,8 function as a genetic switch to down-regulate surrogate light-chain gene expression and induce conventional light-chain gene transcription and rearrangement.
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Affiliation(s)
- Runqing Lu
- Department of Molecular Genetics and Cell Biology, Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
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27
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Elewaut D, Shaikh RB, Hammond KJL, De Winter H, Leishman AJ, Sidobre S, Turovskaya O, Prigozy TI, Ma L, Banks TA, Lo D, Ware CF, Cheroutre H, Kronenberg M. NIK-dependent RelB activation defines a unique signaling pathway for the development of V alpha 14i NKT cells. J Exp Med 2003; 197:1623-33. [PMID: 12810685 PMCID: PMC2193960 DOI: 10.1084/jem.20030141] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2003] [Revised: 04/02/2003] [Accepted: 04/02/2003] [Indexed: 11/04/2022] Open
Abstract
A defect in RelB, a member of the Rel/nuclear factor (NF)-kappa B family of transcription factors, affects antigen presenting cells and the formation of lymphoid organs, but its role in T lymphocyte differentiation is not well characterized. Here, we show that RelB deficiency in mice leads to a selective decrease of NKT cells. RelB must be expressed in an irradiation-resistant host cell that can be CD1d negative, indicating that the RelB expressing cell does not contribute directly to the positive selection of CD1d-dependent NKT cells. Like RelB-deficient mice, aly/aly mice with a mutation for the NF-kappa B-inducing kinase (NIK), have reduced NKT cell numbers. An analysis of NK1.1 and CD44 expression on NKT cells in the thymus of aly/aly mice reveals a late block in development. In vitro, we show that NIK is necessary for RelB activation upon triggering of surface receptors. This link between NIK and RelB was further demonstrated in vivo by analyzing RelB+/- x aly/+ compound heterozygous mice. After stimulation with alpha-GalCer, an antigen recognized by NKT cells, these compound heterozygotes had reduced responses compared with either RelB+/- or aly/+ mice. These data illustrate the complex interplay between hemopoietic and nonhemopoietic cell types for the development of NKT cells, and they demonstrate the unique requirement of NKT cells for a signaling pathway mediated by NIK activation of RelB in a thymic stromal cell.
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MESH Headings
- Animals
- Antigens, CD1/metabolism
- Antigens, CD1d
- Cell Differentiation/physiology
- Cells, Cultured
- Chimera
- Fibroblasts/cytology
- Fibroblasts/metabolism
- Hyaluronan Receptors/metabolism
- Killer Cells, Natural/cytology
- Killer Cells, Natural/immunology
- Killer Cells, Natural/physiology
- Lymphotoxin beta Receptor
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- NF-kappa B/antagonists & inhibitors
- NF-kappa B/metabolism
- Peyer's Patches/anatomy & histology
- Peyer's Patches/metabolism
- Protein Serine-Threonine Kinases/metabolism
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Receptors, Tumor Necrosis Factor/metabolism
- Signal Transduction/physiology
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/physiology
- Thymus Gland/cytology
- Thymus Gland/metabolism
- Transcription Factor RelB
- Transcription Factors/genetics
- Transcription Factors/metabolism
- beta 2-Microglobulin/metabolism
- NF-kappaB-Inducing Kinase
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Affiliation(s)
- Dirk Elewaut
- Division of Developmental Immunology, La Jolla Institute for Allergy and Immunology, 10355 Science Center Dr., San Diego, CA 92121, USA
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28
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Hesslein DGT, Pflugh DL, Chowdhury D, Bothwell ALM, Sen R, Schatz DG. Pax5 is required for recombination of transcribed, acetylated, 5' IgH V gene segments. Genes Dev 2003; 17:37-42. [PMID: 12514097 PMCID: PMC195966 DOI: 10.1101/gad.1031403] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2002] [Accepted: 11/04/2002] [Indexed: 01/31/2023]
Abstract
Pax5-deficient progenitor B (pro-B) cells are thought to be severely defective for recombination of all immunoglobulin heavy chain (IgH) V gene segments, but the mechanism by which Pax5 regulates this process has not been defined. To address this issue, we have examined the assembly of the IgH locus in Pax5-deficient pro-B cells and find, unexpectedly, that 3' IgH V gene segments, which lie closest to the D-J-Cmu region, recombine efficiently, but progressively more distal V gene segments recombine progressively less efficiently. Histone acetylation and germ-line transcription correlate strongly with an open or an accessible chromatin structure thought to be permissive for V(D)J recombination, and defects in recombination are typically accompanied by deficits in these processes. We were therefore surprised to observe that distal V(H) gene segments in Pax5-/- pro-B cells exhibit no defect in these measures of accessibility. The finding of transcribed, histone acetylated gene segments that fail to recombine suggests that a Pax5-dependent regulatory mechanism is required in addition to standard constraints of accessibility to control V(H) gene recombination.
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Affiliation(s)
- David G T Hesslein
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520-8011, USA
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29
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Gong Q, Jin X, Akk AM, Foger N, White M, Gong G, Wardenburg JB, Chan AC. Requirement for tyrosine residues 315 and 319 within zeta chain-associated protein 70 for T cell development. J Exp Med 2001; 194:507-18. [PMID: 11514606 PMCID: PMC2193491 DOI: 10.1084/jem.194.4.507] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Engagement of the T cell antigen receptor (TCR) induces the transphosphorylation of the zeta chain-associated protein of 70,000 Mr (ZAP-70) protein tyrosine kinase (PTK) by the CD4/8 coreceptor associated Lck PTK. Phosphorylation of Tyr 493 within ZAP-70's activation loop results in the enzymatic activation of ZAP-70. Additional tyrosines (Tyrs) within ZAP-70 are phosphorylated that play both positive and negative regulatory roles in TCR function. Phosphorylation of Tyr residues (Tyrs 315 and 319) within the Interdomain B region of the ZAP-70 PTK plays important roles in the generation of second messengers after TCR engagement. Here, we demonstrate that phosphorylation of these two Tyr residues also play important roles in mediating the positive and negative selection of T cells in the thymus.
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Affiliation(s)
- Qian Gong
- Center for Immunology, Department of Medicine
- Division of Rheumatology, Department of Medicine
- Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, MO 63110
| | - Xiaohua Jin
- Center for Immunology, Department of Medicine
- Division of Rheumatology, Department of Medicine
| | - Antonina M. Akk
- Center for Immunology, Department of Medicine
- Division of Rheumatology, Department of Medicine
| | - Niko Foger
- Center for Immunology, Department of Medicine
- Division of Rheumatology, Department of Medicine
- Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, MO 63110
| | - Mike White
- Center for Immunology, Department of Medicine
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Guoqing Gong
- Center for Immunology, Department of Medicine
- Division of Rheumatology, Department of Medicine
| | - Julie Bubeck Wardenburg
- Center for Immunology, Department of Medicine
- Division of Rheumatology, Department of Medicine
| | - Andrew C. Chan
- Center for Immunology, Department of Medicine
- Division of Rheumatology, Department of Medicine
- Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, MO 63110
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30
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Abstract
Although immunoglobulin (Ig)M(hi)IgD(lo/-)CD21(hi) marginal zone B cells represent a significant proportion of naive peripheral splenic B lymphocytes, few of the genes that regulate their development have been identified. This subset of peripheral B cells fails to emerge in mice that lack nuclear factor (NF)-kappa Bp50. Less drastic reductions in marginal zone B cell numbers are also seen in the spleens of recombination activating gene (Rag)-2(-/-) mice reconstituted with NF-kappa Bp65(-/-) fetal liver cells and in c-Rel(-/-) mice. In contrast, steady-state levels of IgD(hi) splenic follicular B cells are not significantly reduced in the absence of NF-kappa Bp50, NF-kappa Bp65, or c-Rel. Reconstitution of B cells in Rag-2(-/-) mice with a mixture of p50(-/-)/p65(-/-) fetal liver cells and Rag-2(-/-) bone marrow cells revealed that the generation of marginal zone B cells requires the expression of NF-kappa B in developing B cells, as opposed to supporting cells.
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Affiliation(s)
- A Cariappa
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts 02129, USA
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31
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Nagaoka H, Gonzalez-Aseguinolaza G, Tsuji M, Nussenzweig MC. Immunization and infection change the number of recombination activating gene (RAG)-expressing B cells in the periphery by altering immature lymphocyte production. J Exp Med 2000; 191:2113-20. [PMID: 10859336 PMCID: PMC2193199 DOI: 10.1084/jem.191.12.2113] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Recombination activating gene (RAG) expression in peripheral B cells increases after immunization with (4-hydroxy-3-nitrophenyl) acetyl coupled to chicken gamma globulin (NP-CGG) in alum. This increase could result from reinduction of RAG expression or, alternatively, from accumulation of RAG-expressing immature B cells in the periphery. We have used mice that carry a green fluorescent protein (GFP) RAG indicator transgene (RAG2-GFP) to characterize the RAG-expressing B cells in immunized spleens. Most of the RAG2-GFP-expressing B cells in unimmunized spleen are immature B cells. Injection with NP-CGG in alum initially suppresses lymphopoiesis in the bone marrow and decreases the number of immature RAG2-GFP-expressing B cells in the spleen. Recovery of lymphopoiesis in the bone marrow coincides with accumulation of RAG-expressing immature B cells in the spleen. Most of the RAG-expressing cells that accumulate in the spleen after immunization do not proliferate and they are not germinal center cells. Neither the initial suppression of lymphopoiesis nor the subsequent accumulation of RAG-expressing cells in the spleen is antigen dependent, since similar changes are seen with alum alone. Furthermore, such changes in the numbers of developing and circulating immature lymphoid cells are seen after injection with complete Freund's adjuvant or malaria infection. Our experiments suggest that adjuvants and infectious agents cause previously unappreciated alterations in lymphopoiesis resulting in the accumulation of RAG-expressing immature B cells in the spleen.
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Affiliation(s)
- Hitoshi Nagaoka
- Laboratory of Molecular Immunology, The Rockefeller University, New York, New York 10021
- Howard Hughes Medical Institute, New York, New York 10021
| | - Gloria Gonzalez-Aseguinolaza
- Department of Medical and Molecular Parasitology, New York University School of Medicine, New York, New York 10010
| | - Moriya Tsuji
- Department of Medical and Molecular Parasitology, New York University School of Medicine, New York, New York 10010
| | - Michel C. Nussenzweig
- Laboratory of Molecular Immunology, The Rockefeller University, New York, New York 10021
- Howard Hughes Medical Institute, New York, New York 10021
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32
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Abstract
We have examined the question of whether there is an additional checkpoint in T cell development that regulates T cell receptor (TCR)-beta expression in CD25+44- thymocytes by mechanisms that are independent of the pre-TCR. Our analysis in various mutant mice indicates that all changes in cytoplasmic TCR-beta expression can be accounted for by pre-TCR-dependent signal mediation, putting into question the function of a putative pro-TCR.
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Affiliation(s)
- I Aifantis
- Institut National de la Santé et de la Recherche Médicale (INSERM) U373, Hôpital Necker-Enfants Malades, Paris, France
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33
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Abstract
During T cell development, thymocytes which are tolerant to self-peptides but reactive to foreign peptides are selected. The current model for thymocyte selection proposes that self-peptide-major histocompatibility complex (MHC) complexes that bind the T cell receptor with low affinity will promote positive selection while those with high affinity will result in negative selection. Upon thymocyte maturation, such low affinity self-peptide-MHC ligands no longer provoke a response, but foreign peptides can incidentally be high affinity ligands and can therefore stimulate T cells. For this model to work, thymocytes must be more sensitive to ligand than mature T cells. Contrary to this expectation, several groups have shown that thymocytes are less responsive than mature T cells to anti-T cell receptor for antigen (TCR)/CD3 mAb stimulation. Additionally, the lower TCR levels on thymocytes, compared with T cells, would potentially correlate with decreased thymocyte sensitivity. Here we compared preselection thymocytes and mature T cells for early activation events in response to peptide-MHC ligands. Remarkably, the preselection thymocytes were more responsive than mature T cells when stimulated with low affinity peptide variants, while both populations responded equally well to the antigenic peptide. This directly demonstrates the increased sensitivity of thymocytes compared with T cells for TCR engagement by peptide-MHC complexes.
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Affiliation(s)
- G M Davey
- Department of Laboratory Medicine and Pathology and Center for Immunology, University of Minnesota, Minneapolis, Minnesota 55455, USA
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34
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Hahm K, Cobb BS, McCarty AS, Brown KE, Klug CA, Lee R, Akashi K, Weissman IL, Fisher AG, Smale ST. Helios, a T cell-restricted Ikaros family member that quantitatively associates with Ikaros at centromeric heterochromatin. Genes Dev 1998; 12:782-96. [PMID: 9512513 PMCID: PMC316626 DOI: 10.1101/gad.12.6.782] [Citation(s) in RCA: 200] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/1997] [Accepted: 01/22/1998] [Indexed: 02/06/2023]
Abstract
The Ikaros gene encodes multiple protein isoforms that contribute critical functions during the development of lymphocytes and other hematopoietic cell types. The intracellular functions of Ikaros are not known, although recent studies have shown that Ikaros proteins colocalize with inactive genes and centromeric heterochromatin. In this study, Ikaros proteins were found to be components of highly stable complexes. The complexes from an immature T cell line were purified, revealing associated proteins of 70 and 30 kD. The p70 gene, named Helios, encodes two protein isoforms with zinc finger domains exhibiting considerable homology to those within Ikaros proteins. Helios and Ikaros recognize similar DNA sequences and, when overexpressed, Helios associates indiscriminately with the various Ikaros isoforms. Although Ikaros is present in most hematopoietic cells, Helios was found primarily in T cells. The relevance of the Ikaros-Helios interaction in T cells is supported by the quantitative association of Helios with a fraction of the Ikaros. Interestingly, the Ikaros-Helios complexes localize to the centromeric regions of T cell nuclei, similar to the Ikaros localization previously observed in B cells. Unlike the B cell results, however, only a fraction of the Ikaros, presumably the fraction associated with Helios, exhibited centromeric localization in T cells. These results establish immunoaffinity chromatography as a useful method for identifying Ikaros partners and suggest that Helios is a limiting regulatory subunit for Ikaros within centromeric heterochromatin.
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Affiliation(s)
- K Hahm
- Howard Hughes Medical Institute, Molecular Biology Institute, and Department of Microbiology and Immunology, UCLA School of Medicine, Los Angeles, California 90095-1662, USA
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35
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Imami N, Ladyman HM, Vincents B, al-Tubuly A, Freysdóttir J, Sedibane ML, Taylor-Fishwick DA, Foxwell BM, Ritter MA. K21-antigen: a molecule shared by the microenvironments of the human thymus and germinal centers. Dev Immunol 1998; 6:41-52. [PMID: 9716904 PMCID: PMC2275999 DOI: 10.1155/1998/29340] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The mouse IgG1 monoclonal antibody (mAb) K21 recognizes a 230-kD molecule (K21-Ag) on Hassall's corpuscles in the human thymus. This mAb also stains cultured thymic epithelial cells as well as other epithelial cell lines, revealing a predominant intracellular localization. Further analysis with mAb K21 on other lymphoid tissues showed that it also stains cells within the germinal centers of human tonsils, both lymphoid (B) cells and some with the appearance of follicular dendritic cells. Double immunostaining of tonsil sections shows that K21-Ag is not expressed by T cells, whereas staining with anti-CD22 and -CD23 mAb revealed some double-positive cells. A subpopulation of the lymphoid cells express the K21-Ag much more strongly. This K21++/CD23++ subpopulation of cells is localized in the apical light zone of germinal centers, suggesting that K21-Ag may be an important marker for the selected centrocytes within germinal centers and may play a role in B-cell selection and/or development of B-cell memory. Flow cytometric analysis showed that K21-Ag is expressed on the surface of a very low percentage of thymocytes, tonsillar lymphocytes, and peripheral blood mononuclear cells. Analysis of purified/separated tonsillar T and B lymphocytes showed that T cells do not express the K21-Ag; in contrast, B cells express low levels of the K21-Ag, and this together with CD23 is upregulated after mitogenic stimulation. Our data therefore raise the possibility that the K21-Ag may play a role in B-lymphocyte activation/selection.
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Affiliation(s)
- N Imami
- Department of Immunology, Imperial College School of Medicine, Hammersmith Hospital, London, United Kingdom
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36
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Abstract
We have previously shown that the adult thymus contains three subsets of gamma delta T cells that can be defined by the expression of THY-1 and heat-stable antigen (HSA). In this study, the number of cells in each of these thymic gamma delta populations was investigated at different stages throughout life. In adult mice, the populations stay relatively constant, however, in contrast, there were major variations in them early in development. It was shown that only two of the gamma delta populations were present in the prenatal thymus, a major population of Thy-1+ HSA - cells, and a smaller population of Thy-1+ HSA+ cells. However, after birth, most of the Thy-1+ HSA - cells appear to loose the Thy-1 antigen, forming the third population of HSA - Thy-1 - cells. The adult configuration of populations appeared to be established within the first week after birth. Therefore, whereas the gamma delta populations stayed relatively constant from this time point onwards, there were major variations early in development. Throughout life, most gamma delta thymocytes are CD4- CD8-, however, in the neonatal thymus, there are some CD+ and CD+ gamma delta thymocytes, and these are contained in the Thy-1+ HSA - population.
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Affiliation(s)
- M I Zorbas
- Walter and Eliza Hall Institute of Medical Research, Post Office Royal Melbourne Hospital, Victoria, Australia
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