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Weyrich A, Hecht W, Köhler K, Herden C, Henrich M. Comparative analysis of primer sets for the assessment of clonality in feline lymphomas. Front Vet Sci 2024; 11:1356330. [PMID: 38774911 PMCID: PMC11106357 DOI: 10.3389/fvets.2024.1356330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 04/22/2024] [Indexed: 05/24/2024] Open
Abstract
Introduction Lymphomas are among the most important and common malignant tumors in cats. Differentiating lymphomas from reactive lymphoid proliferations can be challenging, so additional tools such as clonality assessment by PCR are important in diagnosis finding. Several PCR assays have been developed to assess clonality in feline lymphomas. For T-cell lymphomas TRG (T-cell receptor gamma) genes are the preferred target whereas for B-cell lymphomas most primer sets target immunoglobulin heavy chain (IGH) genes. Here we compare commonly used diagnostic primer sets for the assessment of clonality in feline lymphomas under controlled conditions (i.e., identical sample set, PCR setup, amplicon detection system). Methods Formalin-fixed and paraffin-embedded samples from 31 feline T-cell lymphomas, 29 B-cell lymphomas, and 11 non-neoplastic controls were analyzed by PCR combined with capillary electrophoresis. Results and discussion We show that the combination of the primer sets published by Weiss et al. and Mochizuki et al. provided the best results for T-cell clonality, i.e., correctly assigns most populations as clonal or polyclonal. For B-cell clonality, the combination of the primer sets by Mochizuki et al. and Rout et al. gave the best results when omitting the Kde gene rearrangement due to its low specificity. This study rigorously evaluated various primer sets under uniform experimental conditions to improve accuracy of lymphoma diagnostic and provides a recommendation for achieving the highest diagnostic precision in lymphoma clonality analysis.
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Affiliation(s)
| | | | | | | | - Manfred Henrich
- Institut für Veterinär-Pathologie, Justus-Liebig-Universität Giessen, Giessen, Germany
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2
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Zhang R, Wang D, Ruan GX, Wang R, Li Y, Chen W, Huang H, Wang J, Meng L, Zhu Z, Lei D, Xu S, Ou X. Spliceosome component PHD finger 5A is essential for early B lymphopoiesis. Development 2024; 151:dev202247. [PMID: 38095286 DOI: 10.1242/dev.202247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 12/08/2023] [Indexed: 01/12/2024]
Abstract
The spliceosome, a multi-megadalton ribonucleoprotein complex, is essential for pre-mRNA splicing in the nucleus and ensuring genomic stability. Its precise and dynamic assembly is pivotal for its function. Spliceosome malfunctions can lead to developmental abnormalities and potentially contribute to tumorigenesis. The specific role of the spliceosome in B cell development is poorly understood. Here, we reveal that the spliceosomal U2 snRNP component PHD finger protein 5A (Phf5a) is vital for early B cell development. Loss of Phf5a results in pronounced defects in B cell development, causing an arrest at the transition from pre-pro-B to early pro-B cell stage in the bone marrow of mutant mice. Phf5a-deficient B cells exhibit impaired immunoglobulin heavy (IgH) chain expression due to defective V-to-DJ gene rearrangement. Mechanistically, our findings suggest that Phf5a facilitates IgH gene rearrangement by regulating the activity of recombination-activating gene endonuclease and influencing chromatin interactions at the Igh locus.
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Affiliation(s)
- Rui Zhang
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Daoqin Wang
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Gui-Xin Ruan
- Medical School, Taizhou University, Taizhou 318000, China
| | - Ruisi Wang
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yuxing Li
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wenjing Chen
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Hengjun Huang
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jing Wang
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Limin Meng
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zhijian Zhu
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Dengfeng Lei
- Department of Ophthalmology, Southern University of Science and Technology Hospital, Shenzhen 518055, China
| | - Shengli Xu
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, Immunos, Singapore 138648, Republic of Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 2 Medical Drive MD9, Singapore 117593, Republic of Singapore
| | - Xijun Ou
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
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3
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Lopes R, Caetano J, Barahona F, Pestana C, Ferreira BV, Lourenço D, Queirós AC, Bilreiro C, Shemesh N, Beck HC, Carvalho AS, Matthiesen R, Bogen B, Costa-Silva B, Serre K, Carneiro EA, João C. Multiple Myeloma-Derived Extracellular Vesicles Modulate the Bone Marrow Immune Microenvironment. Front Immunol 2022; 13:909880. [PMID: 35874665 PMCID: PMC9302002 DOI: 10.3389/fimmu.2022.909880] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/23/2022] [Indexed: 01/10/2023] Open
Abstract
Multiple myeloma (MM), the third most frequent hematological cancer worldwide, is characterized by the proliferation of neoplastic plasma cells in the bone marrow (BM). One of the hallmarks of MM is a permissive BM microenvironment. Increasing evidence suggests that cell-to-cell communication between myeloma and immune cells via tumor cell-derived extracellular vesicles (EV) plays a key role in the pathogenesis of MM. Hence, we aimed to explore BM immune alterations induced by MM-derived EV. For this, we inoculated immunocompetent BALB/cByJ mice with a myeloma cell line, MOPC315.BM, inducing a MM phenotype. Upon tumor establishment, characterization of the BM microenvironment revealed the expression of both activation and suppressive markers by lymphocytes, such as granzyme B and PD-1, respectively. In addition, conditioning of the animals with MOPC315.BM-derived EV, before transplantation of the MOPC315.BM tumor cells, did not anticipate the disease phenotype. However, it induced features of suppression in the BM milieu, such as an increase in PD-1 expression by CD4+ T cells. Overall, our findings reveal the involvement of MOPC315.BM-derived EV protein content as promoters of immune niche remodeling, strengthening the importance of assessing the mechanisms by which MM may impact the immune microenvironment.
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Affiliation(s)
- Raquel Lopes
- Myeloma Lymphoma Research Group, Champalimaud Experimental Clinical Research Programme, Champalimaud Foundation, Lisbon, Portugal
- Faculty of Medicine, University of Lisbon, Lisbon, Portugal
| | - Joana Caetano
- Myeloma Lymphoma Research Group, Champalimaud Experimental Clinical Research Programme, Champalimaud Foundation, Lisbon, Portugal
- Hemato-Oncology Department, Champalimaud Foundation, Lisbon, Portugal
- Faculty of Medical Sciences, NOVA Medical School (NMS), Lisbon, Portugal
| | - Filipa Barahona
- Myeloma Lymphoma Research Group, Champalimaud Experimental Clinical Research Programme, Champalimaud Foundation, Lisbon, Portugal
- Faculty of Medical Sciences, NOVA Medical School (NMS), Lisbon, Portugal
| | - Carolina Pestana
- Myeloma Lymphoma Research Group, Champalimaud Experimental Clinical Research Programme, Champalimaud Foundation, Lisbon, Portugal
- Centre of Statistics and Its Applications, Faculty of Sciences, University of Lisbon, Lisbon, Portugal
| | - Bruna Velosa Ferreira
- Myeloma Lymphoma Research Group, Champalimaud Experimental Clinical Research Programme, Champalimaud Foundation, Lisbon, Portugal
- Hemato-Oncology Department, Champalimaud Foundation, Lisbon, Portugal
- Faculty of Medical Sciences, NOVA Medical School (NMS), Lisbon, Portugal
| | - Diana Lourenço
- Myeloma Lymphoma Research Group, Champalimaud Experimental Clinical Research Programme, Champalimaud Foundation, Lisbon, Portugal
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Ana C. Queirós
- Myeloma Lymphoma Research Group, Champalimaud Experimental Clinical Research Programme, Champalimaud Foundation, Lisbon, Portugal
| | - Carlos Bilreiro
- Faculty of Medical Sciences, NOVA Medical School (NMS), Lisbon, Portugal
- Neural Plasticity and Neural Activity Laboratory, Champalimaud Experimental Clinical Research Programme, Champalimaud Foundation, Lisbon, Portugal
- Radiology Department, Champalimaud Foundation, Lisbon, Portugal
| | - Noam Shemesh
- Neural Plasticity and Neural Activity Laboratory, Champalimaud Experimental Clinical Research Programme, Champalimaud Foundation, Lisbon, Portugal
| | - Hans Christian Beck
- Centre for Clinical Proteomics, Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark
| | - Ana Sofia Carvalho
- Computational and Experimental Biology, Chronic Diseases Research Centre (CEDOC); NOVA Medical School (NMS), Lisbon, Portugal
| | - Rune Matthiesen
- Computational and Experimental Biology, Chronic Diseases Research Centre (CEDOC); NOVA Medical School (NMS), Lisbon, Portugal
| | - Bjarne Bogen
- Institute of Immunology, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Bruno Costa-Silva
- Systems Oncology, Champalimaud Physiology and Cancer Programme, Champalimaud Foundation, Lisbon, Portugal
| | - Karine Serre
- Molecular Medicine Institute-Laço Hub, Instituto de Medicina Molecular João Lobo Antunes, Lisbon, Portugal
| | - Emilie Arnault Carneiro
- Myeloma Lymphoma Research Group, Champalimaud Experimental Clinical Research Programme, Champalimaud Foundation, Lisbon, Portugal
| | - Cristina João
- Myeloma Lymphoma Research Group, Champalimaud Experimental Clinical Research Programme, Champalimaud Foundation, Lisbon, Portugal
- Hemato-Oncology Department, Champalimaud Foundation, Lisbon, Portugal
- Faculty of Medical Sciences, NOVA Medical School (NMS), Lisbon, Portugal
- *Correspondence: Cristina João,
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4
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Glynn RA, Bassing CH. Nemo-Dependent, ATM-Mediated Signals from RAG DNA Breaks at Igk Feedback Inhibit V κ Recombination to Enforce Igκ Allelic Exclusion. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:371-383. [PMID: 34965965 PMCID: PMC8756740 DOI: 10.4049/jimmunol.2100696] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 11/01/2021] [Indexed: 01/17/2023]
Abstract
Monoallelic AgR gene expression underlies specific adaptive immune responses. AgR allelic exclusion is achieved by sequential initiation of V(D)J recombination between alleles and resultant protein from one allele signaling to prevent recombination of the other. The ATM kinase, a regulator of the DNA double-strand break (DSB) response, helps enforce allelic exclusion through undetermined mechanisms. ATM promotes repair of RAG1/RAG2 (RAG) endonuclease-induced DSBs and transduces signals from RAG DSBs during Igk gene rearrangement on one allele to transiently inhibit RAG1 protein expression, Igk accessibility, and RAG cleavage of the other allele. Yet, the relative contributions of ATM functions in DSB repair versus signaling to enforce AgR allelic exclusion remain undetermined. In this study, we demonstrate that inactivation in mouse pre-B cells of the NF-κB essential modulator (Nemo) protein, an effector of ATM signaling, diminishes RAG DSB-triggered repression of Rag1/Rag2 transcription and Igk accessibility but does not result in aberrant repair of RAG DSBs like ATM inactivation. We show that Nemo deficiency increases simultaneous biallelic Igk cleavage in pre-B cells and raises the frequency of B cells expressing Igκ proteins from both alleles. In contrast, the incidence of biallelic Igκ expression is not elevated by inactivation of the SpiC transcriptional repressor, which is induced by RAG DSBs in an ATM-dependent manner and suppresses Igk accessibility. Thus, we conclude that Nemo-dependent, ATM-mediated DNA damage signals enforce Igκ allelic exclusion by orchestrating transient repression of RAG expression and feedback inhibition of additional Igk rearrangements in response to RAG cleavage on one Igk allele.
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Affiliation(s)
- Rebecca A. Glynn
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104,Department of Pathology and Laboratory Medicine, Children’s Hospital of Pennsylvania, Philadelphia, PA 19104
| | - Craig H. Bassing
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104,Department of Pathology and Laboratory Medicine, Children’s Hospital of Pennsylvania, Philadelphia, PA 19104,Corresponding Author: Craig H. Bassing, Ph.D., Children’s Hospital of Philadelphia, 4054 Colket Translational Research Building, 3501 Civic Center Blvd., Philadelphia, PA 19104, 267-426-0311,
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5
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Abstract
Each of us is a story. Mine is a story of doing science for 60 years, and I am honored to be asked to tell it. Even though this autobiography was written for the Annual Review of Immunology, I have chosen to describe my whole career in science because the segment that was immunology is so intertwined with all else I was doing. This article is an elongation and modification of a talk I gave at my 80th birthday celebration at Caltech on March 23, 2018.
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Affiliation(s)
- David Baltimore
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA
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6
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Collins AM, Watson CT. Immunoglobulin Light Chain Gene Rearrangements, Receptor Editing and the Development of a Self-Tolerant Antibody Repertoire. Front Immunol 2018; 9:2249. [PMID: 30349529 PMCID: PMC6186787 DOI: 10.3389/fimmu.2018.02249] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 09/10/2018] [Indexed: 11/13/2022] Open
Abstract
Discussion of the antibody repertoire usually emphasizes diversity, but a conspicuous feature of the light chain repertoire is its lack of diversity. The diversity of reported allelic variants of germline light chain genes is also limited, even in well-studied species. In this review, the implications of this lack of diversity are considered. We explore germline and rearranged light chain genes in a variety of species, with a particular focus on human and mouse genes. The importance of the number, organization and orientation of the genes for the control of repertoire development is discussed, and we consider how primary rearrangements and receptor editing together shape the expressed light chain repertoire. The resulting repertoire is dominated by just a handful of IGKV and IGLV genes. It has been hypothesized that an important function of the light chain is to guard against self-reactivity, and the role of secondary rearrangements in this process could explain the genomic organization of the light chain genes. It could also explain why the light chain repertoire is so limited. Heavy and light chain genes may have co-evolved to ensure that suitable light chain partners are usually available for each heavy chain that forms early in B cell development. We suggest that the co-evolved loci of the house mouse often became separated during the inbreeding of laboratory mice, resulting in new pairings of loci that are derived from different sub-species of the house mouse. A resulting vulnerability to self-reactivity could explain at least some mouse models of autoimmune disease.
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Affiliation(s)
- Andrew M. Collins
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Corey T. Watson
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, United States
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7
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Arya R, Bassing CH. V(D)J Recombination Exploits DNA Damage Responses to Promote Immunity. Trends Genet 2017; 33:479-489. [PMID: 28532625 PMCID: PMC5499712 DOI: 10.1016/j.tig.2017.04.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 04/25/2017] [Accepted: 04/26/2017] [Indexed: 11/16/2022]
Abstract
It has been recognized for 40 years that the variable (diversity) joining [V(D)J] recombination-mediated assembly of diverse B and T lymphocyte antigen receptor (AgR) genes is not only essential for adaptive immunity, but also a risk for autoimmunity and lymphoid malignancies. Over the past few years, several studies have revealed that recombination-activating gene (RAG) endonuclease-induced DNA double-strand breaks (DSBs) transcend hazardous intermediates during antigen receptor gene assembly. RAG cleavage within the genomes of lymphocyte progenitors and immature lymphocytes regulates the expression of ubiquitous and lymphocyte-specific gene transcripts to control the differentiation and function of both adaptive and innate immune cell lineages. These unexpected discoveries raise important new questions that have broad implications for basic immunology research and the screening, diagnosis, and treatment of human immunological disease.
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Affiliation(s)
- Rahul Arya
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Craig H Bassing
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
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8
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Jensen CT, Lang S, Somasundaram R, Soneji S, Sigvardsson M. Identification of Stage-Specific Surface Markers in Early B Cell Development Provides Novel Tools for Identification of Progenitor Populations. THE JOURNAL OF IMMUNOLOGY 2016; 197:1937-44. [PMID: 27456481 DOI: 10.4049/jimmunol.1600297] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 06/22/2016] [Indexed: 11/19/2022]
Abstract
Whereas the characterization of B lymphoid progenitors has been facilitated by the identification of lineage- and stage-specific surface markers, the continued identification of differentially expressed proteins increases our capacity to explore normal and malignant B cell development. To identify novel surface markers with stage-specific expression patterns, we explored the reactivity of CD19(+) B cell progenitor cells to Abs targeted to 176 surface proteins. Markers with stage-specific expression were identified using a transgenic reporter gene system subdividing the B cell progenitors into four surface IgM(-) stages. This approach affirmed the utility of known stage-specific markers, as well as identifying additional proteins that selectively marked defined stages of B cell development. Among the stage-specific markers were the cell adhesion proteins CD49E, CD11A, and CD54 that are highly expressed selectively on the most immature progenitors. This work identifies a set of novel stage-specific surface markers that can be used as a complement to the classical staining protocols to explore B lymphocyte development.
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Affiliation(s)
- Christina T Jensen
- Department of Molecular Hematology, Lund University, 22184 Lund, Sweden; and
| | - Stefan Lang
- Department of Molecular Hematology, Lund University, 22184 Lund, Sweden; and
| | - Rajesh Somasundaram
- Department of Clinical and Experimental Medicine, Linköping University, 58185 Linköping, Sweden
| | - Shamit Soneji
- Department of Molecular Hematology, Lund University, 22184 Lund, Sweden; and
| | - Mikael Sigvardsson
- Department of Molecular Hematology, Lund University, 22184 Lund, Sweden; and Department of Clinical and Experimental Medicine, Linköping University, 58185 Linköping, Sweden
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9
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Outters P, Jaeger S, Zaarour N, Ferrier P. Long-Range Control of V(D)J Recombination & Allelic Exclusion: Modeling Views. Adv Immunol 2015; 128:363-413. [PMID: 26477371 DOI: 10.1016/bs.ai.2015.08.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Allelic exclusion of immunoglobulin (Ig) and T-cell receptor (TCR) genes ensures the development of B and T lymphocytes operating under the mode of clonal selection. This phenomenon associates asynchronous V(D)J recombination events at Ig or TCR alleles and inhibitory feedback control. Despite years of intense research, however, the mechanisms that sustain asymmetric choice in random Ig/TCR dual allele usage and the production of Ig/TCR monoallelic expressing B and T lymphocytes remain unclear and open for debate. In this chapter, we first recapitulate the biological evidence that almost from the start appeared to link V(D)J recombination and allelic exclusion. We review the theoretical models previously proposed to explain this connection. Finally, we introduce our own mathematical modeling views based on how the developmental dynamics of individual lymphoid cells combine to sustain allelic exclusion.
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Affiliation(s)
- Pernelle Outters
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288 Marseille, France
| | - Sébastien Jaeger
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288 Marseille, France
| | - Nancy Zaarour
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288 Marseille, France
| | - Pierre Ferrier
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille Université UM2, Inserm, U1104, CNRS UMR7280, 13288 Marseille, France.
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10
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de Almeida CR, Hendriks RW, Stadhouders R. Dynamic Control of Long-Range Genomic Interactions at the Immunoglobulin κ Light-Chain Locus. Adv Immunol 2015; 128:183-271. [DOI: 10.1016/bs.ai.2015.07.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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11
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Li JSS, Shin GJE, Millard SS. Neuronal cell-type-specific alternative splicing: A mechanism for specifying connections in the brain? NEUROGENESIS 2015; 2:e1122699. [PMID: 27606331 PMCID: PMC4973604 DOI: 10.1080/23262133.2015.1122699] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/16/2015] [Indexed: 02/05/2023]
Abstract
Alternative splicing (AS) allows a single gene to generate multiple protein isoforms. It has been hypothesized that AS plays a role in brain wiring by increasing the number of cell recognition molecules necessary for forming connections between neurons. Many studies have characterized isoform expression patterns of various genes in the brain, but very few have addressed whether specific isoforms play a functional role in neuronal wiring. In our recent work, we reported the cell-type-specific AS of the cell recognition molecule Dscam2. Exclusive expression of Dscam2 isoforms allows tightly associated neurons to signal repulsion selectively within the same cell-types, without interfering with one another. We show that preventing cell-specific isoform expression in 2 closely associated neurons disrupts their axon terminal morphology. We propose that the requirement for isoform specificity extends to synapses and discuss experiments that can test this directly. Factors that regulate Dscam2 cell-type-specific AS likely regulate the splicing of many genes involved in neurodevelopment. These regulators of alternative splicing may act broadly to control many genes involved in the development of specific neuron types. Identifying these factors is a key step in understanding how AS contributes to the brain connectome.
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Affiliation(s)
- Joshua Shing Shun Li
- School of Biomedical Sciences; The University of Queensland ; Brisbane, QLD, Australia
| | - Grace Ji-Eun Shin
- School of Biomedical Sciences; The University of Queensland ; Brisbane, QLD, Australia
| | - S Sean Millard
- School of Biomedical Sciences; The University of Queensland ; Brisbane, QLD, Australia
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12
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Steinel NC, Fisher MR, Yang-Iott KS, Bassing CH. The ataxia telangiectasia mutated and cyclin D3 proteins cooperate to help enforce TCRβ and IgH allelic exclusion. THE JOURNAL OF IMMUNOLOGY 2014; 193:2881-90. [PMID: 25127855 DOI: 10.4049/jimmunol.1302201] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Coordination of V rearrangements between loci on homologous chromosomes is critical for Ig and TCR allelic exclusion. The Ataxia Telangietasia mutated (ATM) protein kinase promotes DNA repair and activates checkpoints to suppress aberrant Ig and TCR rearrangements. In response to RAG cleavage of Igκ loci, ATM inhibits RAG expression and suppresses further Vκ-to-Jκ rearrangements to enforce Igκ allelic exclusion. Because V recombination between alleles is more strictly regulated for TCRβ and IgH loci, we evaluated the ability of ATM to restrict biallelic expression and V-to-DJ recombination of TCRβ and IgH genes. We detected greater frequencies of lymphocytes with biallelic expression or aberrant V-to-DJ rearrangement of TCRβ or IgH loci in mice lacking ATM. A preassembled DJβ complex that decreases the number of TCRβ rearrangements needed for a productive TCRβ gene further increased frequencies of ATM-deficient cells with biallelic TCRβ expression. IgH and TCRβ proteins drive proliferation of prolymphocytes through cyclin D3 (Ccnd3), which also inhibits VH transcription. We show that inactivation of Ccnd3 leads to increased frequencies of lymphocytes with biallelic expression of IgH or TCRβ genes. We also show that Ccnd3 inactivation cooperates with ATM deficiency to increase the frequencies of cells with biallelic TCRβ or IgH expression while decreasing the frequency of ATM-deficient lymphocytes with aberrant V-to-DJ recombination. Our data demonstrate that core components of the DNA damage response and cell cycle machinery cooperate to help enforce IgH and TCRβ allelic exclusion and indicate that control of V-to-DJ rearrangements between alleles is important to maintain genomic stability.
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Affiliation(s)
- Natalie C Steinel
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104; Abramson Family Cancer Research Institute, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; and Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Megan R Fisher
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104; Abramson Family Cancer Research Institute, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; and Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Katherine S Yang-Iott
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104; Abramson Family Cancer Research Institute, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; and
| | - Craig H Bassing
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104; Abramson Family Cancer Research Institute, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; and Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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13
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Comparison of reverse transcription quantitative real-time PCR, flow cytometry, and immunohistochemistry for detection of monoclonality in lymphomas. ISRN ONCOLOGY 2014; 2014:796210. [PMID: 24649374 PMCID: PMC3932212 DOI: 10.1155/2014/796210] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 12/24/2013] [Indexed: 11/18/2022]
Abstract
In healthy humans, 60–70% of the B lymphocytes produce kappa light chains, while the remaining cells produce lambda light chains. Malignant transformation and clonal expansion of B lymphocytes lead to an altered kappa : lambda expression ratio, which is an important diagnostic criteria of lymphomas. Here, we compared three methods for clonality determination of suspected B cell lymphomas. Tumor biopsies from 55 patients with B cell malignancies, 5 B-lymphoid tumor cell lines, and 20 biopsies from patients with lymphadenitis were analyzed by immunohistochemistry, flow cytometry, and reverse transcription quantitative real-time PCR. Clonality was determined by immunohistochemistry in 52/53 cases, flow cytometry in 30/39 cases, and reverse transcription quantitative real-time PCR in 33/55 cases. In conclusion, immunohistochemistry was superior to flow cytometry and reverse transcription quantitative real-time PCR for clonality identification. Flow cytometry and reverse transcription quantitative real-time PCR analysis has complementary values. In a considerable number of cases tumor cells produced both kappa and lambda light chain transcripts, but only one type of light chain peptide was produced.
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Nishana M, Raghavan SC. Role of recombination activating genes in the generation of antigen receptor diversity and beyond. Immunology 2013; 137:271-81. [PMID: 23039142 DOI: 10.1111/imm.12009] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Revised: 08/19/2012] [Accepted: 08/21/2012] [Indexed: 01/18/2023] Open
Abstract
V(D)J recombination is the process by which antibody and T-cell receptor diversity is attained. During this process, antigen receptor gene segments are cleaved and rejoined by non-homologous DNA end joining for the generation of combinatorial diversity. The major players of the initial process of cleavage are the proteins known as RAG1 (recombination activating gene 1) and RAG2. In this review, we discuss the physiological function of RAGs as a sequence-specific nuclease and its pathological role as a structure-specific nuclease. The first part of the review discusses the basic mechanism of V(D)J recombination, and the last part focuses on how the RAG complex functions as a sequence-specific and structure-specific nuclease. It also deals with the off-target cleavage of RAGs and its implications in genomic instability.
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15
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Steinel NC, Lee BS, Tubbs AT, Bednarski JJ, Schulte E, Yang-Iott KS, Schatz DG, Sleckman BP, Bassing CH. The ataxia telangiectasia mutated kinase controls Igκ allelic exclusion by inhibiting secondary Vκ-to-Jκ rearrangements. ACTA ACUST UNITED AC 2013; 210:233-9. [PMID: 23382544 PMCID: PMC3570110 DOI: 10.1084/jem.20121605] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
DNA double-strand breaks induced during Igκ recombination signal through ATM to suppress the initiation of additional Vκ-to-Jκ rearrangements. Allelic exclusion is enforced through the ability of antigen receptor chains expressed from one allele to signal feedback inhibition of V-to-(D)J recombination on the other allele. To achieve allelic exclusion by such means, only one allele can initiate V-to-(D)J recombination within the time required to signal feedback inhibition. DNA double-strand breaks (DSBs) induced by the RAG endonuclease during V(D)J recombination activate the Ataxia Telangiectasia mutated (ATM) and DNA-dependent protein kinase (DNA-PK) kinases. We demonstrate that ATM enforces Igκ allelic exclusion, and that RAG DSBs induced during Igκ recombination in primary pre–B cells signal through ATM, but not DNA-PK, to suppress initiation of additional Igκ rearrangements. ATM promotes high-density histone H2AX phosphorylation to create binding sites for MDC1, which functions with H2AX to amplify a subset of ATM-dependent signals. However, neither H2AX nor MDC1 is required for ATM to enforce Igκ allelic exclusion and suppress Igκ rearrangements. Upon activation in response to RAG Igκ cleavage, ATM signals down-regulation of Gadd45α with concomitant repression of the Gadd45α targets Rag1 and Rag2. Our data indicate that ATM kinases activated by RAG DSBs during Igκ recombination transduce transient H2AX/MDC1-independent signals that suppress initiation of further Igκ rearrangements to control Igκ allelic exclusion.
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Affiliation(s)
- Natalie C Steinel
- Immunology Graduate Group, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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16
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17
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Zimmerman AM, Romanowski KE, Maddox BJ. Targeted annotation of immunoglobulin light chain (IgL) genes in zebrafish from BAC clones reveals kappa-like recombining/deleting elements within IgL constant regions. FISH & SHELLFISH IMMUNOLOGY 2011; 31:697-703. [PMID: 20933599 DOI: 10.1016/j.fsi.2010.09.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 09/09/2010] [Accepted: 09/20/2010] [Indexed: 05/30/2023]
Abstract
Genomic organization, composition, and microsynteny of immunoglobulin light chain (IgL) gene segments in the zebrafish were analyzed through the identification and annotation of overlapping BAC clone insert sequences and an Illumina de novo assembly. The resultant gap-free IgL annotation confirmed a number of previous conclusions about teleost IgL including: suites of (V(L)-J(L)-C(L)) clusters on multiple chromosomes; V(L) in the same or opposite transcriptional orientation as J(L) and C(L); and the apparent absence of lambda IgL in the zebrafish model. In addition, palindromic heptamers (CACAGTG or CACTGTG) within the 3' region of zebrafish C(L) were identified. In mammals, heptamers within J(κ)-C(κ) introns can recombine with downstream kappa deleting elements (Kde) to ablate C(κ) regions prior to rearrangements of V(λ)-J(λ) gene segments. The presence of palindromic heptamers within zebrafish C(L) is intriguing as their recombination with intact RSS might result in the deletion of a large portion of the C(L) thereby permanently silencing C(L) exons within the IgL locus. Given that bony fish have appreciably more C(L) spread over more chromosomes than mice and humans, it is plausible the presence of recombining sequences within C(L) may be tied to a need for heightened mechanisms to facilitate allelic exclusion or receptor editing. Collectively, with this report, gap-free annotations of the heavy and light chain Ig loci have now been completed for Danio rerio, the only teleost for which this has been accomplished, thereby strengthening the overall utility of zebrafish as a model organism for both comparative immunology and biomedical research.
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Affiliation(s)
- Anastasia M Zimmerman
- Department of Biology, College of Charleston, 66 George Street, Charleston, SC 29424, USA.
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Del Blanco B, García V, García-Mariscal A, Hernández-Munain C. Control of V(D)J Recombination through Transcriptional Elongation and Changes in Locus Chromatin Structure and Nuclear Organization. GENETICS RESEARCH INTERNATIONAL 2011; 2011:970968. [PMID: 22567371 PMCID: PMC3335570 DOI: 10.4061/2011/970968] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 07/29/2011] [Indexed: 01/29/2023]
Abstract
V(D)J recombination is the assembly of gene segments at the antigen receptor loci to
generate antigen receptor diversity in T and B lymphocytes. This process is regulated,
according to defined developmental programs, by the action of a single specific
recombinase complex formed by the recombination antigen gene (RAG-1/2) proteins
that are expressed in immature lymphocytes. V(D)J recombination is strictly controlled
by RAG-1/2 accessibility to specific recombination signal sequences in chromatin at
several levels: cellular lineage, temporal regulation, gene segment order, and allelic
exclusion. DNA cleavage by RAG-1/2 is regulated by the chromatin structure,
transcriptional elongation, and three-dimensional architecture and position of the
antigen receptor loci in the nucleus. Cis-elements specifically direct transcription and
V(D)J recombination at these loci through interactions with transacting factors that form
molecular machines that mediate a sequence of structural events. These events open
chromatin to activate transcriptional elongation and to permit the access of RAG-1/2 to
their recombination signal sequences to drive the juxtaposition of the V, D, and J
segments and the recombination reaction itself. This chapter summarizes the advances
in this area and the important role of the structure and position of antigen receptor loci
within the nucleus to control this process.
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Affiliation(s)
- Beatriz Del Blanco
- Instituto de Parasitología y Biomedicina López-Neyra (IPBLN-CSIC), Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento s/n. 18100 Armilla, Spain
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19
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Luning Prak ET, Monestier M, Eisenberg RA. B cell receptor editing in tolerance and autoimmunity. Ann N Y Acad Sci 2011; 1217:96-121. [PMID: 21251012 DOI: 10.1111/j.1749-6632.2010.05877.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Receptor editing is the process of ongoing antibody gene rearrangement in a lymphocyte that already has a functional antigen receptor. The expression of a functional antigen receptor will normally terminate further rearrangement (allelic exclusion). However, lymphocytes with autoreactive receptors have a chance at escaping negative regulation by "editing" the specificities of their receptors with additional antibody gene rearrangements. As such, editing complicates the Clonal Selection Hypothesis because edited cells are not simply endowed for life with a single, invariant antigen receptor. Furthermore, if the initial immunoglobulin gene is not inactivated during the editing process, allelic exclusion is violated and the B cell can exhibit two specificities. Here, we describe the discovery of editing, the pathways of receptor editing at the heavy (H) and light (L) chain loci, and current evidence regarding how and where editing happens and what effects it has on the antibody repertoire.
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Affiliation(s)
- Eline T Luning Prak
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
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20
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Das S, Hirano M, McCallister C, Tako R, Nikolaidis N. Comparative genomics and evolution of immunoglobulin-encoding loci in tetrapods. Adv Immunol 2011; 111:143-78. [PMID: 21970954 DOI: 10.1016/b978-0-12-385991-4.00004-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The immunoglobulins (Igs or antibodies) as an integral part of the tetrapod adaptive immune response system have evolved toward producing highly diversified molecules that recognize a remarkably large number of different antigens. Antibodies and their respective encoding loci have been shaped by different and often contrasting evolutionary forces, some of which aim to conserve an established pattern or mechanism and others to generate alternative and diversified structural and functional configurations. The genomic organization, gene content, ratio between functional genes and pseudogenes, number and position of recombining genetic elements, and the different levels of divergence present at the germline of the Ig-encoding loci have been evolutionarily shaped and optimized in a lineage- and, in some cases, species-specific mode aiming to increase organismal fitness. Further, evolution favored the development of multiple mechanisms of primary and secondary antibody diversification, such as V(D)J recombination, class switch recombination, isotype exclusion, somatic hypermutation, and gene conversion. Diverse tetrapod species, based on their specific germline configurations, use these mechanisms in several different combinations to effectively generate a vast array of distinct antibody types and structures. This chapter summarizes our current knowledge on the Ig-encoding loci in tetrapods and discusses the different evolutionary mechanisms that shaped their diversification.
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Affiliation(s)
- Sabyasachi Das
- Department of Pathology and Laboratory Medicine, Emory Vaccine Center, School of Medicine, Emory University, Atlanta, Georgia, USA
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21
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Brady BL, Steinel NC, Bassing CH. Antigen receptor allelic exclusion: an update and reappraisal. THE JOURNAL OF IMMUNOLOGY 2010; 185:3801-8. [PMID: 20858891 DOI: 10.4049/jimmunol.1001158] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Most lymphocytes express cell surface Ag receptor chains from single alleles of distinct Ig or TCR loci. Since the identification of Ag receptor allelic exclusion, the importance of this process and the precise molecular mechanisms by which it is achieved have remained enigmatic. This brief review summarizes current knowledge of the extent to which Ig and TCR loci are subject to allelic exclusion. Recent progress in studying and defining mechanistic steps and molecules that may control the monoallelic initiation and subsequent inhibition of V-to-(D)-J recombination is outlined using the mouse TCRβ locus as a model with frequent comparisons to the mouse IgH and Igκ loci. Potential consequences of defects in mechanisms that control Ag receptor allelic exclusion and a reappraisal of the physiologic relevance of this immunologic process also are discussed.
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Affiliation(s)
- Brenna L Brady
- Immunology Graduate Group, Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Abramson Family Cancer Research Institute, Philadelphia, PA 19104, USA
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22
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Abstract
The allelic exclusion of immunoglobulin (Ig) genes is one of the most evolutionarily conserved features of the adaptive immune system and underlies the monospecificity of B cells. While much has been learned about how Ig allelic exclusion is established during B-cell development, the relevance of monospecificity to B-cell function remains enigmatic. Here, we review the theoretical models that have been proposed to explain the establishment of Ig allelic exclusion and focus on the molecular mechanisms utilized by developing B cells to ensure the monoallelic expression of Ig kappa and Ig lambda light chain genes. We also discuss the physiological consequences of Ig allelic exclusion and speculate on the importance of monospecificity of B cells for immune recognition.
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Affiliation(s)
- Christian Vettermann
- Division of Immunology & Pathogenesis, Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
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23
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Das S, Nikolaidis N, Nei M. Genomic organization and evolution of immunoglobulin kappa gene enhancers and kappa deleting element in mammals. Mol Immunol 2009; 46:3171-7. [PMID: 19560204 PMCID: PMC2736800 DOI: 10.1016/j.molimm.2009.05.180] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 05/30/2009] [Indexed: 11/20/2022]
Abstract
We have studied the genomic structure and evolutionary pattern of immunoglobulin kappa deleting element (KDE) and three kappa enhancers (KE5', KE3'P, and KE3'D) in eleven mammalian genomic sequences. Our results show that the relative positions and the genomic organization of the KDE and the kappa enhancers are conserved in all mammals studied and have not been affected by the local rearrangements in the immunoglobulin kappa (IGK) light chain locus over a long evolutionary time ( approximately 120 million years of mammalian evolution). Our observations suggest that the sequence motifs in these regulatory elements have been conserved by purifying selection to achieve proper regulation of the expression of the IGK light chain genes. The conservation of the three enhancers in all mammals indicates that these species may use similar mechanisms to regulate IGK gene expression. However, some activities of the IGK enhancers might have evolved in the eutherian lineage. The presence of the three IGK enhancers, KDE, and other recombining elements (REs) in all mammals (including platypus) suggest that these genomic elements were in place before the mammalian radiation.
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Affiliation(s)
- Sabyasachi Das
- Department of Pathology and Laboratory Medicine, Emory Vaccine Center, School of Medicine, Emory University, Atlanta, GA 30322, USA.
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24
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Perlot T, Alt FW. Cis-regulatory elements and epigenetic changes control genomic rearrangements of the IgH locus. Adv Immunol 2009; 99:1-32. [PMID: 19117530 DOI: 10.1016/s0065-2776(08)00601-9] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Immunoglobulin variable region exons are assembled from discontinuous variable (V), diversity (D), and joining (J) segments by the process of V(D)J recombination. V(D)J rearrangements of the immunoglobulin heavy chain (IgH) locus are tightly controlled in a tissue-specific, ordered and allele-specific manner by regulating accessibility of V, D, and J segments to the recombination activating gene proteins which are the specific components of the V(D)J recombinase. In this review we discuss recent advances and established models brought forward to explain the mechanisms underlying accessibility control of V(D)J recombination, including research on germline transcripts, spatial organization, and chromatin modifications of the immunoglobulin heavy chain (IgH) locus. Furthermore, we review the functions of well-described and potential new cis-regulatory elements with regard to processes such as V(D)J recombination, allelic exclusion, and IgH class switch recombination.
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Affiliation(s)
- Thomas Perlot
- The Howard Hughes Medical Institute, The Children's Hospital, Immune Disease Institute, Harvard Medical School, Boston, Massachusetts, USA
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25
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Schram BR, Tze LE, Ramsey LB, Liu J, Najera L, Vegoe AL, Hardy RR, Hippen KL, Farrar MA, Behrens TW. B cell receptor basal signaling regulates antigen-induced Ig light chain rearrangements. THE JOURNAL OF IMMUNOLOGY 2008; 180:4728-41. [PMID: 18354197 DOI: 10.4049/jimmunol.180.7.4728] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BCR editing in the bone marrow contributes to B cell tolerance by orchestrating secondary Ig rearrangements in self-reactive B cells. We have recently shown that loss of the BCR or a pharmacologic blockade of BCR proximal signaling pathways results in a global "back-differentiation" response in which immature B cells down-regulate genes important for the mature B cell program and up-regulate genes characteristic of earlier stages of B cell development. These observations led us to test the hypothesis that self-Ag-induced down-regulation of the BCR, and not self-Ag-induced positive signals, lead to Rag induction and hence receptor editing. Supporting this hypothesis, we found that immature B cells from xid (x-linked immunodeficiency) mice induce re-expression of a Rag2-GFP bacterial artificial chromosome reporter as well as wild-type immature B cells following Ag incubation. Incubation of immature B cells with self-Ag leads to a striking reversal in differentiation to the pro-/pre-B stage of development, consistent with the idea that back-differentiation results in the reinduction of genes required for L chain rearrangement and receptor editing. Importantly, Rag induction, the back-differentiation response to Ag, and editing in immature and pre-B cells are inhibited by a combination of phorbol ester and calcium ionophore, agents that bypass proximal signaling pathways and mimic BCR signaling. Thus, mimicking positive BCR signals actually inhibits receptor editing. These findings support a model whereby Ag-induced receptor editing is inhibited by BCR basal signaling on developing B cells; BCR down-regulation removes this basal signal, thereby initiating receptor editing.
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Affiliation(s)
- Brian R Schram
- Center for Immunology, Department of Medicine, University of Minnesota Medical School, University of Minnesota, Minneapolis, MN 55455, USA
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26
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Alt FW. From gene amplification to V(D)J recombination and back: a personal account of my early years in B cell biology. Eur J Immunol 2007; 37 Suppl 1:S138-47. [PMID: 17972338 PMCID: PMC2572819 DOI: 10.1002/eji.200737848] [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] [Indexed: 11/07/2022]
Abstract
I have been invited to write a short historical feature in the context of being a co-recipient with Klaus Rajewsky and Fritz Melchers of the 2007 Novartis Prize in Basic Immunology that was given in the general area of the molecular biology of B cells. In this feature, I cover the main points of the short talk that I presented at the Award Ceremony at the International Immunology Congress in Rio de Janeiro, Brazil. This talk focused primarily on the work and people involved early on in generating the models and ideas that have formed the basis for my ongoing efforts in the areas of V(D)J recombination and B cell development.
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Affiliation(s)
- Frederick W Alt
- Howard Hughes Medical Institute, The Children's Hospital, The Immune Disease Institute, Department of Genetics, Harvard Medical School, Boston, MA 02215, USA.
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27
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Daly J, Licence S, Nanou A, Morgan G, Mårtensson IL. Transcription of productive and nonproductive VDJ-recombined alleles after IgH allelic exclusion. EMBO J 2007; 26:4273-82. [PMID: 17805345 PMCID: PMC2230841 DOI: 10.1038/sj.emboj.7601846] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Accepted: 08/08/2007] [Indexed: 01/18/2023] Open
Abstract
The process of allelic exclusion ensures that each B cell expresses a B-cell receptor encoded by only one of its Ig heavy (IgH) and light (IgL) chain alleles. Although its precise mechanism is unknown, recruitment of the nonfunctional IgH allele to centromeric heterochromatin correlates with the establishment of allelic exclusion. Similarly, recruitment in activated splenic B cells correlates with cell division. In the latter, the recruited IgH allele was reported to be transcriptionally silent. However, it is not known whether monoallelic recruitment during establishment of allelic exclusion correlates with transcriptional silencing. To investigate this, we assessed the transcriptional status of both IgH alleles in single primary cells over the course of B-cell development, using RNA fluorescence in situ hybridization. Before allelic exclusion both alleles are transcribed. Thereafter, in pre-BII and subsequent developmental stages both functional and nonfunctional VDJ- and DJ-transcription is observed. Thus, after the establishment of IgH allelic exclusion, monoallelic recruitment to heterochromatin does not silence VDJ- or DJ-transcription, but serves another purpose.
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Affiliation(s)
- Janssen Daly
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Cambridge, UK
| | - Steve Licence
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Cambridge, UK
| | - Aikaterini Nanou
- Chromatin and Gene expression, The Babraham Institute, Cambridge, UK
| | - Geoff Morgan
- Flow Cytometry Facility, The Babraham Institute, Cambridge, UK
| | - Inga-Lill Mårtensson
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Cambridge, UK
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, The Babraham Research Campus, Cambridge CB2 4AT, UK. Tel.: +44 1223 496469; Fax: +44 1223 496023; E-mail:
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28
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Maiti M, Kumar GS. Molecular aspects on the interaction of protoberberine, benzophenanthridine, and aristolochia group of alkaloids with nucleic acid structures and biological perspectives. Med Res Rev 2007; 27:649-95. [PMID: 16894530 DOI: 10.1002/med.20087] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Alkaloids occupy an important position in chemistry and pharmacology. Among the various alkaloids, berberine and coralyne of the protoberberine group, sanguinarine of the benzophenanthridine group, and aristololactam-beta-d-glucoside of the aristolochia group have potential to form molecular complexes with nucleic acid structures and have attracted recent attention for their prospective clinical and pharmacological utility. This review highlights (i) the physicochemical properties of these alkaloids under various environmental conditions, (ii) the structure and functional aspects of various forms of deoxyribonucleic acid (DNA) (B-form, Z-form, H(L)-form, protonated form, and triple helical form) and ribonucleic acid (RNA) (A-form, protonated form, and triple helical form), and (iii) the interaction of these alkaloids with various polymorphic DNA and RNA structures reported by several research groups employing various analytical techniques like absorbance, fluorescence, circular dichroism, and NMR spectroscopy; electrospray ionization mass spectrometry, thermal melting, viscosity, and DNase footprinting as well as molecular modeling and thermodynamic studies to provide detailed binding mechanism at the molecular level for structure-activity relationship. Nucleic acids binding properties of these alkaloids are interpreted in relation to their biological activity.
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Affiliation(s)
- Motilal Maiti
- Biophysical Chemistry Laboratory, Indian Institute of Chemical Biology, Kolkata 700 032, India.
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29
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Jung D, Giallourakis C, Mostoslavsky R, Alt FW. Mechanism and control of V(D)J recombination at the immunoglobulin heavy chain locus. Annu Rev Immunol 2006; 24:541-70. [PMID: 16551259 DOI: 10.1146/annurev.immunol.23.021704.115830] [Citation(s) in RCA: 435] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
V(D)J recombination assembles antigen receptor variable region genes from component germline variable (V), diversity (D), and joining (J) gene segments. For B cells, such rearrangements lead to the production of immunoglobulin (Ig) proteins composed of heavy and light chains. V(D)J is tightly controlled at the Ig heavy chain locus (IgH) at several different levels, including cell-type specificity, intra- and interlocus ordering, and allelic exclusion. Such controls are mediated at the level of gene segment accessibility to V(D)J recombinase activity. Although much has been learned, many long-standing questions regarding the regulation of IgH locus rearrangements remain to be elucidated. In this review, we summarize advances that have been made in understanding how V(D)J recombination at the IgH locus is controlled and discuss important areas for future investigation.
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Affiliation(s)
- David Jung
- Howard Hughes Medical Institute, Children's Hospital, CBR Institute for Biomedical Research, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
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30
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Hirayama T, Yagi T. The role and expression of the protocadherin-alpha clusters in the CNS. Curr Opin Neurobiol 2006; 16:336-42. [PMID: 16697637 DOI: 10.1016/j.conb.2006.05.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Accepted: 05/03/2006] [Indexed: 10/24/2022]
Abstract
The clustered protocadherins comprise the largest subfamily of the cadherin superfamily and are predominantly expressed in the nervous system. The family of clustered protocadherins (clustered Pcdh family) is substructured into three distinct gene arrays in mammals: Pcdh-alpha, Pcdh-beta, and Pcdh-gamma. These are regulated by multiple promoters and cis-alternative splicing without DNA recombination. Pcdh-alpha proteins interact with beta1-integrin to promote cell adhesion. They also form oligomers with Pcdh-gamma proteins at the same membrane sites. During neuronal maturation, Pcdh-alpha expression is dramatically downregulated by myelination. The clustered Pcdh family has multiple variable exons that differ somewhat in number and sequence across vertebrate species. At the single-cell level, Pcdh-alpha mRNAs are regulated monoallelically, resulting in the combinatorial expression of distinct variable exons from each allele. These findings support the idea that diversified Pcdh molecules contribute to neural circuit development and provide individual cells with their specific identity.
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Affiliation(s)
- Teruyoshi Hirayama
- KOKORO-Biology Group, Laboratories for Integrated Biology, Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan
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31
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Franklin A. Hypothesis: a biological role for germline transcription in the mechanism of V(D)J recombination--implications for initiation of allelic exclusion. Immunol Cell Biol 2006; 84:396-403. [PMID: 16594898 DOI: 10.1111/j.1440-1711.2006.01437.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The sequences that encode the antigen-binding sites of IgH and IgL chains - variable (V), diversity (D, H chain loci only) and joining (J) sequences - are configured as separate DNA segments at the germline level. Expression of an Ig molecule requires V(D)J assembly. Productive V(D)J recombination is monoallelic. How rearrangement is initiated differentially at maternal and paternal alleles is unclear. The products of recombination activating gene (RAG)1 and RAG2 mediate rearrangement by cleaving the DNA between an unrearranged gene segment and adjacent recombination signal sequences (RSS). It is proposed that supercoiling generated during germline transcription at Ig loci (which occurs concomitantly with rearrangement) is required at RSS for RAG1/2 recognition. Rearrangement might hence initiate sequentially at maternal and paternal alleles where deregulated germline transcription causes RAG1/2 recognition of RSS to become stochastic.
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Affiliation(s)
- Andrew Franklin
- Biocontrol Group, School of Botany and Zoology, Australian National University, Canberra, Australian Capital Territory, Australia.
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32
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Dudley DD, Chaudhuri J, Bassing CH, Alt FW. Mechanism and control of V(D)J recombination versus class switch recombination: similarities and differences. Adv Immunol 2006; 86:43-112. [PMID: 15705419 DOI: 10.1016/s0065-2776(04)86002-4] [Citation(s) in RCA: 214] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
V(D)J recombination is the process by which the variable region exons encoding the antigen recognition sites of receptors expressed on B and T lymphocytes are generated during early development via somatic assembly of component gene segments. In response to antigen, somatic hypermutation (SHM) and class switch recombination (CSR) induce further modifications of immunoglobulin genes in B cells. CSR changes the IgH constant region for an alternate set that confers distinct antibody effector functions. SHM introduces mutations, at a high rate, into variable region exons, ultimately allowing affinity maturation. All of these genomic alteration processes require tight regulatory control mechanisms, both to ensure development of a normal immune system and to prevent potentially oncogenic processes, such as translocations, caused by errors in the recombination/mutation processes. In this regard, transcription of substrate sequences plays a significant role in target specificity, and transcription is mechanistically coupled to CSR and SHM. However, there are many mechanistic differences in these reactions. V(D)J recombination proceeds via precise DNA cleavage initiated by the RAG proteins at short conserved signal sequences, whereas CSR and SHM are initiated over large target regions via activation-induced cytidine deaminase (AID)-mediated DNA deamination of transcribed target DNA. Yet, new evidence suggests that AID cofactors may help provide an additional layer of specificity for both SHM and CSR. Whereas repair of RAG-induced double-strand breaks (DSBs) involves the general nonhomologous end-joining DNA repair pathway, and CSR also depends on at least some of these factors, CSR requires induction of certain general DSB response factors, whereas V(D)J recombination does not. In this review, we compare and contrast V(D)J recombination and CSR, with particular emphasis on the role of the initiating enzymes and DNA repair proteins in these processes.
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Affiliation(s)
- Darryll D Dudley
- Howard Hughes Medical Institute, The Children's Hospital Boston, CBR Institute for Biomedical Research, and Harvard Medical School, Boston, MA 02115, USA
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33
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Couderc J. [B lymphocytes--a dogma revisited]. C R Biol 2005; 328:758-66. [PMID: 16125653 DOI: 10.1016/j.crvi.2005.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2005] [Accepted: 05/17/2005] [Indexed: 11/26/2022]
Abstract
The one B cell-one antibody hypothesis proposed by M.F. Burnet (1957) was recently challenged by results showing that one B cell can simultaneously express an auto-reactive BCR, and a BCR directed against non-self antigens. The latter allows this auto-reactive B cell to escape negative selection. Burnet's theory was thus challenged from the beginning. Namely, Liacopoulos et al. demonstrated that normal B cells produce simultaneously or sequentially two antibody molecules against two unrelated haptens. It thus appears that 'double producers' provide new prospects in auto-immunity. Our previous work using heterologous antigens also suggest that 'double producers' provide an amplifying factor for immunoglobulin repertoire.
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Affiliation(s)
- Jacques Couderc
- Inserm 131, Cytokines et Immunorégulations, 32, rue des Carnets, 92140 Clamart, France.
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34
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Bergman Y, Cedar H. A stepwise epigenetic process controls immunoglobulin allelic exclusion. Nat Rev Immunol 2004; 4:753-61. [PMID: 15459667 DOI: 10.1038/nri1458] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
During the differentiation of T and B cells, immune-receptor loci in the genome must be made sterically accessible so that they can undergo rearrangement. Here, we discuss how this is carried out by the stepwise removal of epigenetic repression mechanisms - such as later-replication timing, heterochromatization, histone hypo-acetylation and DNA methylation - in a manner that initially favours one allele in each cell. We propose that this mechanism of allelic exclusion might also be the basis for the generation of gene diversity in other systems.
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Affiliation(s)
- Yehudit Bergman
- Department of Experimental Medicine, Hebrew University Medical School, Ein Kerem, Jerusalem 91120, Israel
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35
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Abstract
B lymphocytes produce diverse antibody specificities by "randomly" assembling antibody genes from germline segments. Yet, though each B lymphocyte has multiple allelic loci for the different antibody chains, each clonally derived mature B lymphocyte expresses a single species of antibody with a unique specificity via a process termed allelic exclusion. Despite some progress, the precise mechanism of allelic exclusion remains an enigma.
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Affiliation(s)
- Raul Mostoslavsky
- Howard Hughes Medical Institute, The Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
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36
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Abstract
V(D)J recombination assembles antigen receptor genes from component gene segments. We review findings that have shaped our current understanding of this remarkable mechanism, with a focus on two major reports--the first detailed comparison of germline and rearranged antigen receptor loci and the discovery of the recombination activating gene-1.
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Affiliation(s)
- David Jung
- Howard Hughes Medical Institute, The Children's Hospital, The CBR Institute for Biomedical Research, Inc., Harvard Medical School, Boston, MA 02115, USA
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37
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Hasan M, Polic B, Bralic M, Jonjic S, Rajewsky K. Incomplete block of B cell development and immunoglobulin production in mice carrying the muMT mutation on the BALB/c background. Eur J Immunol 2002; 32:3463-71. [PMID: 12442328 DOI: 10.1002/1521-4141(200212)32:12<3463::aid-immu3463>3.0.co;2-b] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The expression of the preB cell receptor (preBCR), composed of the mu chain, surrogate light chains and the Igalpha /Igbeta signal transduction unit, permits further differentiation of Bcell precursors. C57BL/6 mice homozygous for an inactivating mutation of the membrane exon of the mu chain gene (C57BL/6muMT/muMT)) cannot form a preBCR and are, consequently, devoid of mature B lymphocytes. Here we present evidence that the block of B cell development by the muMT mutation is incomplete in BALB/c mice. Unlike C57BL/6muMT/muMT), BALB/cmuMT/muMT) mice generate small numbers of mature B cells, accumulate plasma cells and produce high levels of all immunoglobulin isotypes, except IgM. The observed phenomenon seems to be controlled by a single genetic locus that is not linked to IgH.
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Affiliation(s)
- Milena Hasan
- Department of Histology and Embryology, Medical Faculty, University of Rijeka, Rijeka, Croatia
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38
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Abstract
V(D)J recombination is of fundamental importance to the generation of diverse antigen receptor repertoires. We review our current understanding of the V(D)J recombination reaction and how it is regulated during lymphocyte development. We also discuss how defects in the mechanism or regulation of V(D)J recombination can lead to human disease.
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Affiliation(s)
- Craig H Bassing
- Howard Hughes Medical Institute, The Children's Hospital, The Center for Blood Research, Boston, MA 02115, USA
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39
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Abstract
Allotype and isotype exclusion is a property of most lymphocytes. The reason for this property is not known but it guarantees a high concentration of a single receptor, and threshold numbers of receptors may be required for efficient positive and negative selection. Receptor editing compromises exclusion by sustaining recombination even after a functional receptor is formed. Consequently, B cells expressing multiple receptors arise. We have studied such B cells in which one of the two receptors is anti-self, and find that these partially autoreactive B cells accumulate in the marginal zone. The restriction of these cells in this location may help to prevent them from undergoing diversification and developing into fully autoreactive B cells.
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Affiliation(s)
- Yijin Li
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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40
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Hsueh RC, Scheuermann RH. Tyrosine kinase activation in the decision between growth, differentiation, and death responses initiated from the B cell antigen receptor. Adv Immunol 2001; 75:283-316. [PMID: 10879287 DOI: 10.1016/s0065-2776(00)75007-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Immunoglobulin-containing receptors expressed on B lineage lymphocytes play critical roles in the development and function of the humoral arm of the immune system. The preB cell antigen receptor (preBCR) contains the immunoglobulin mu heavy chain (Ig mu) and signals to the preB cell that heavy chain rearrangement has been successful, a process termed heavy chain selection. The B cell antigen receptor (BCR) contains both Ig heavy and light chains and is expressed on immature and mature B cells before and after antigen encounter. Both receptor types from a complex with the Ig alpha and Ig beta proteins that link the predominantly extracellular Ig with intracellular signal transduction pathways. Signaling through the BCR induces different cellular responses depending on the nature of the signaling agent and the development stage of the target cell. These responses include clonal anergy and apoptotic deletion in immature B cells and survival, proliferation, and differentiation in mature B and preB cells. Several protein tyrosine kinases are activated rapidly following engagement of the BCR/preBCR complexes, including members of the Src family (Lyn and Blk), the Syk/ZAP70 family (Syk), and the Tec family (Btk). In this review, we discuss possible mechanisms by which engagement of these similar receptor complexes can give rise to different cellular responses and the role that these kinases play in this process.
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MESH Headings
- Agammaglobulinaemia Tyrosine Kinase
- Antibody Formation
- Antigens, CD/genetics
- Antigens, CD/immunology
- Apoptosis/physiology
- B-Lymphocyte Subsets/cytology
- B-Lymphocyte Subsets/enzymology
- B-Lymphocyte Subsets/immunology
- CD79 Antigens
- Cell Differentiation/physiology
- Cell Division/physiology
- Enzyme Activation
- Enzyme Precursors/physiology
- Genes, Immunoglobulin
- Hematopoietic Stem Cells/cytology
- Hematopoietic Stem Cells/immunology
- Humans
- Immune Tolerance
- Immunoglobulin Heavy Chains/genetics
- Immunologic Deficiency Syndromes/enzymology
- Immunologic Deficiency Syndromes/genetics
- Immunologic Deficiency Syndromes/immunology
- Intracellular Signaling Peptides and Proteins
- Lymphocyte Activation
- Phosphorylation
- Plasma Cells/cytology
- Plasma Cells/immunology
- Protein Processing, Post-Translational
- Protein-Tyrosine Kinases/physiology
- Receptors, Antigen, B-Cell/genetics
- Receptors, Antigen, B-Cell/immunology
- Receptors, Antigen, B-Cell/physiology
- Recombinant Fusion Proteins/immunology
- Signal Transduction
- Syk Kinase
- ZAP-70 Protein-Tyrosine Kinase
- src Homology Domains
- src-Family Kinases/deficiency
- src-Family Kinases/genetics
- src-Family Kinases/physiology
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Affiliation(s)
- R C Hsueh
- Laboratory of Molecular Pathology, University of Texas Southwestern Medical Center, Dallas 75235, USA
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van der Burg M, Tümkaya T, Boerma M, de Bruin-Versteeg S, Langerak AW, van Dongen JJ. Ordered recombination of immunoglobulin light chain genes occurs at the IGK locus but seems less strict at the IGL locus. Blood 2001; 97:1001-8. [PMID: 11159529 DOI: 10.1182/blood.v97.4.1001] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Regulation of allelic and isotypic exclusion of human immunoglobulin (Ig) light-chain genes was studied in 113 chronic B-cell leukemias as a "single-cell" model that allowed complete analysis of each light chain allele. Our data show that monospecific Ig light chain expression is in about 90% of cases determined by ordered recombination: Igkappa gene (IGK) rearrangements, followed by IGK deletions and Iglambda gene (IGL) rearrangements, resulting in the presence of only one functional Ig light chain rearrangement. In about 10% (10 cases), 2 functional Ig light chain rearrangements (IGK/IGL or IGL/IGL, but not IGK/IGK) were identified. This might be explained by the fact that regulation of the ordered recombination process is not fully strict, particularly when the IGL locus is involved. Unfavorable somatic mutations followed by receptor editing might have contributed to this finding. Eight of these 10 cases indeed contained somatic mutations. In cases with 2 functional Ig light chain rearrangements, both alleles were transcribed, but monospecific Ig expression was still maintained. This suggests that in these cases allelelic exclusion is not regulated at the messenger RNA level but either at the level of translation or protein stability or via preferential pairing of Ig light and Ig heavy chains. Nevertheless, ordered rearrangement processes are the main determinant for monospecific Ig light chain expression.
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MESH Headings
- Alleles
- Clone Cells/immunology
- Gene Expression Regulation
- Gene Rearrangement, B-Lymphocyte, Light Chain
- Genes, Immunoglobulin
- Humans
- Immunoglobulin kappa-Chains/genetics
- Immunoglobulin lambda-Chains/genetics
- Leukemia, Lymphocytic, Chronic, B-Cell/genetics
- Mutation
- Neoplasm Proteins/genetics
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Recombination, Genetic
- Reverse Transcriptase Polymerase Chain Reaction
- Transcription, Genetic
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Affiliation(s)
- M van der Burg
- Department of Immunology, Erasmus University Rotterdam/ University Hospital Rotterdam, Rotterdam, The Netherlands
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42
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Ruetsch NR, Bosma GC, Bosma MJ. Unexpected rearrangement and expression of the immunoglobulin lambda1 locus in scid mice. J Exp Med 2000; 191:1933-43. [PMID: 10839808 PMCID: PMC2213526 DOI: 10.1084/jem.191.11.1933] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2000] [Accepted: 04/07/2000] [Indexed: 11/25/2022] Open
Abstract
In severe combined immunodeficient (scid) mice, V(D)J recombination is severely impaired due to a recessive mutation (scid). Thus, we were surprised to find in this study that Vlambda1-Jlambda1 rearrangement is routinely detectable in scid fetal liver, adult bone marrow, and spleen in the apparent absence of completed VH-DJH and Vkappa-Jkappa rearrangements. Particularly surprising, we found the level of Vlambda1-Jlambda1 rearrangement in scid fetal liver to be comparable to that in fetal liver of wild-type mice. The majority of scid Vlambda1-Jlambda1 rearrangements contained abnormal deletions at the VJ junction, consistent with the known effect of scid. However, approximately 15% of Vlambda1-Jlambda1 rearrangements lacked abnormal deletions. Productive lambda1 transcripts resulting from in-frame rearrangements were readily detectable in scid adult bone marrow and spleen, consistent with our ability to detect lambda1-expressing cells by flow cytometry in the spleens of bcl-2-transgenic scid mice. Strikingly, lambda1 transcripts from individual scid mice often showed VJ junctional sequences with the same recurring palindromic (P) additions of three, four, or five nucleotides. To account for these findings, we suggest that (a) nonhomologous end joining of Vlambda1 and Jlambda1 coding ends in fetal B lineage cells may not be (severely) impaired by scid; (b) recurring P additions in scid lambda1 transcripts may reflect certain molecular constraints imposed by scid on the resolution of Vlambda1 and Jlambda1 hairpin coding ends; and (c), scid lymphocytes with productively rearranged Vlambda1 and Jlambda1 elements may differentiate into recombinase-inactive cells and emigrate from bone marrow to spleen.
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Affiliation(s)
- Norman R. Ruetsch
- Fox Chase Cancer Center, Institute for Cancer Research, Philadelphia, Pennsylvania 19111
| | - Gayle C. Bosma
- Fox Chase Cancer Center, Institute for Cancer Research, Philadelphia, Pennsylvania 19111
| | - Melvin J. Bosma
- Fox Chase Cancer Center, Institute for Cancer Research, Philadelphia, Pennsylvania 19111
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43
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Abstract
The process of clonal selection is a central feature of the immune system, but immune specificity is also regulated by receptor selection, in which the fate of a lymphocyte's antigen receptor is uncoupled from that of the cell itself. Whereas clonal selection controls cell death or survival in response to antigen receptor signaling, receptor selection regulates the process of V(D)J recombination, which can alter or fix antigen receptor specificity. Receptor selection is carried out in both T and B cells and can occur at different stages of lymphocyte differentiation, in which it plays a key role in allelic exclusion, positive selection, receptor editing, and the diversification of the antigen receptor repertoire. Thus, the immune system takes advantage of its control of V(D)J recombination to modify antigen receptors in such a way that self/non-self discrimination is enhanced. New information about receptor editing in T cells and B-1 B cells is also discussed.
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Affiliation(s)
- D Nemazee
- Department of Immunology, Scripps Research Institute, La Jolla, California 92037, USA.
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44
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Affiliation(s)
- D Nemazee
- Scripps Research Institute, La Jolla, California, USA
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45
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Yamagami T, ten Boekel E, Schaniel C, Andersson J, Rolink A, Melchers F. Four of five RAG-expressing JCkappa-/- small pre-BII cells have no L chain gene rearrangements: detection by high-efficiency single cell PCR. Immunity 1999; 11:309-16. [PMID: 10514009 DOI: 10.1016/s1074-7613(00)80106-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Single cell PCR assays have been further developed that detect over 80% of all VkappaJkappa, VkappaRS, and VlambdaJlambda rearrangements at efficiencies between 70% and 90%. These IgL chain gene rearrangement assays were used with small pre-BII cells that develop in comparably high numbers in the bone marrow of wild-type, Ckappa-deficient, and JCkappa-deficient homozygous and heterozygous mice. In all of these mice, only 15%-25% of all small pre-BII cells carry VlambdaJlambda rearrangements. These results confirm that lambdaL chain gene rearrangements occur independently of kappaL chain gene rearrangement and expression. They also show that a large part of the small pre-BII cells that express the rearrangement machinery can develop without IgL chain gene rearrangements.
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Affiliation(s)
- T Yamagami
- Basel Institute for Immunology, Switzerland
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46
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Krishnan IS, Hansen HJ, Gold DV, Goldenberg DM, Leung SO. Co-secretion of two distinct kappa light chains by the mu-9 hybridoma. Hybridoma (Larchmt) 1999; 18:325-33. [PMID: 10571262 DOI: 10.1089/hyb.1999.18.325] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mu-9 is a monoclonal antibody (MAb) specific for the CSAp antigen (Ag) expressed by colorectal cancers. By using variable (V)-region-specific primers, the respective VH and VL sequences of Mu-9 were polymerase chain reaction (PCR)-amplified. However, chimeric Ab (cMu-9-1) constructed from these PCR-amplified V sequences failed to bind the CSAp Ag. Although the light chain of murine Mu-9 was not glycosylated, that of cMu-9-1 was found to be O-glycosylated, as confirmed by reducing SDS-PAGE analyses, glycoprotein blotting and O-linked specific deglycosylation studies. Removal of O-linked oligosaccharides either by enzymatic digestion or by blocking O-glycosylation with a specific inhibitor did not restore the immunoreactivity of cMu-9-1, indicating that light chain O-glycosylation was not the cause for lack of immunoreactivity. We reported earlier that screening of a Mu-9 cDNA library uncovered the presence of an additional light chain sequence that was later proven to be the authentic light chain of Mu-9. Analyses of the cDNA sequence encoding the nonimmunoreactive light chain, however, revealed no defects that would preclude the sequence from being translated and secreted by the murine hybridoma. By adapting the Mu-9 hybridoma culture to serum-free conditions, we confirmed the secretion of low levels of O-glycosylated light chain. The biological significance of the O-glycosylation as well as the cosecretion of both light chains with respect to allelic exclusion are discussed.
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47
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Shaw AC, Swat W, Davidson L, Alt FW. Induction of Ig light chain gene rearrangement in heavy chain-deficient B cells by activated Ras. Proc Natl Acad Sci U S A 1999; 96:2239-43. [PMID: 10051625 PMCID: PMC26767 DOI: 10.1073/pnas.96.5.2239] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
During B cell development, rearrangement and expression of Ig heavy chain (HC) genes promote development and expansion of pre-B cells accompanied by the onset of Ig light chain (LC) variable region gene assembly. To elucidate the signaling pathways that control these events, we have tested the ability of activated Ras expression to promote B cell differentiation to the stage of LC gene rearrangement in the absence of Ig HC gene expression. For this purpose, we introduced an activated Ras expression construct into JH-deleted embryonic stem cells that lack the ability to assemble HC variable region genes and assayed differentiation potential by recombination activating gene (RAG) 2-deficient blastocyst complementation. We found that activated Ras expression induces the progression of B lineage cells beyond the developmental checkpoint ordinarily controlled by mu HC. Such Ras/JH-deleted B cells accumulate in the periphery but continue to express markers associated with precursor B cells including RAG gene products. These peripheral Ras/JH-deleted B cell populations show extensive Ig LC gene rearrangement but maintain an extent of kappa LC gene rearrangement and a preference for kappa over lambda LC gene rearrangement similar to that of wild-type B cells. We discuss these findings in the context of potential mechanisms that may regulate Ig LC gene rearrangement.
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Affiliation(s)
- A C Shaw
- Howard Hughes Medical Institute, Boston, MA 02115, USA.
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48
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Sleckman BP, Khor B, Monroe R, Alt FW. Assembly of productive T cell receptor delta variable region genes exhibits allelic inclusion. J Exp Med 1998; 188:1465-71. [PMID: 9782123 PMCID: PMC2213415 DOI: 10.1084/jem.188.8.1465] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/1998] [Indexed: 11/26/2022] Open
Abstract
The generation of a productive "in-frame" T cell receptor beta (TCR beta), immunoglobulin (Ig) heavy (H) or Ig light (L) chain variable region gene can result in the cessation of rearrangement of the alternate allele, a process referred to as allelic exclusion. This process ensures that most alphabeta T cells express a single TCR beta chain and most B cells express single IgH and IgL chains. Assembly of TCR alpha and TCR gamma chain variable region genes exhibit allelic inclusion and alphabeta and gammadelta T cells can express two TCR alpha or TCR gamma chains, respectively. However, it was not known whether assembly of TCR delta variable regions genes is regulated in the context of allelic exclusion. To address this issue, we have analyzed TCR delta rearrangements in a panel of mouse splenic gammadelta T cell hybridomas. We find that, similar to TCR alpha and gamma variable region genes, assembly of TCR delta variable region genes exhibits properties of allelic inclusion. These findings are discussed in the context of gammadelta T cell development and regulation of rearrangement of TCR delta genes.
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Affiliation(s)
- B P Sleckman
- Howard Hughes Medical Institute, Children's Hospital and Department of Genetics, Harvard Medical School and The Center for Blood Research, Boston, Massachusetts 02115, USA
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49
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Affiliation(s)
- J R Gorman
- Howard Hughes Medical Institute, Children's Hospital, Boston, Massachusetts 02115, USA
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50
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Abstract
Using a set of surface markers including IgD and CD38, human tonsillar B cells were classified into discrete subpopulations. Molecular and functional analysis allowed us to identify: i) two sets of naive B cells (Bm1 and Bm2); ii) germinal center founder cells (Bm2'); iii) an obscure population of germinal center B cells, displaying a high load of somatic mutations in IgV genes, C mu to C delta switch and preferential Ig lambda light chain usage: these cells may represent the precursors of normal and malignant IgD-secreting plasma cells; iv) the centroblasts (Bm3) in which somatic mutation machinery is activated; v) the centrocytes (Bm4) in which isotype switch occurs; vi) the memory B cells. The characterization of these subpopulations showed that: i) programmed cell death is set before somatic mutations, possibly providing an efficient way for affinity maturation; ii) only high affinity centrocytes are allowed to switch isotype; iii) CD40-ligation inhibits plasmacytic differentiation of mature B lymphocytes; iv) memory B cells preferentially differentiate into plasma cells; v) IgD isotype switch occurs in normal B cells; vi) receptor editing may be induced by somatic mutations in germinal centers. We also characterized two types of antigen-presenting cells in germinal centers: follicular dendritic cells that select high affinity B cells, and a new subset of germinal center dendritic cells that activate germinal center T cells.
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Affiliation(s)
- Y J Liu
- Schering-Plough, Laboratory for Immunological Research, Dardilly, France
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