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Corrected and Republished from: BCL11A Is a Critical Component of a Transcriptional Network That Activates RAG Expression and V(D)J Recombination. Mol Cell Biol 2017; 38:MCB.00362-17. [PMID: 29038163 DOI: 10.1128/mcb.00362-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 08/30/2017] [Indexed: 12/13/2022] Open
Abstract
Recombination activating gene 1 (RAG1) and RAG2 are critical enzymes for initiating variable-diversity-joining [V(D)J] segment recombination, an essential process for antigen receptor expression and lymphocyte development. The BCL11A transcription factor is required for B cell and plasmacytoid dendritic cell (pDC) development, but its molecular function(s) in early B cell fate specification and commitment is unknown. We show here that the major B cell isoform, BCL11A-XL, binds directly to the RAG1 promoter as well as directly to regulatory regions of transcription factors previously implicated in both B cell and pDC development to activate RAG1 and RAG2 gene transcription in pro- and pre-B cells. We employed BCL11A overexpression with recombination substrates to demonstrate direct consequences of BCL11A/RAG modulation on V(D)J recombination. We conclude that BCL11A is a critical component of a transcriptional network that regulates B cell fate by controlling V(D)J recombination.
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The BCL11A transcription factor directly activates RAG gene expression and V(D)J recombination. Mol Cell Biol 2013; 33:1768-81. [PMID: 23438597 DOI: 10.1128/mcb.00987-12] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Recombination-activating gene 1 protein (RAG1) and RAG2 are critical enzymes for initiating variable-diversity-joining (VDJ) segment recombination, an essential process for antigen receptor expression and lymphocyte development. The transcription factor BCL11A is required for B cell development, but its molecular function(s) in B cell fate specification and commitment is unknown. We show here that the major B cell isoform, BCL11A-XL, binds the RAG1 promoter and Erag enhancer to activate RAG1 and RAG2 transcription in pre-B cells. We employed BCL11A overexpression with recombination substrates in a cultured pre-B cell line as well as Cre recombinase-mediated Bcl11a(lox/lox) deletion in explanted murine pre-B cells to demonstrate direct consequences of BCL11A/RAG modulation on V(D)J recombination. We conclude that BCL11A is a critical component of a transcriptional network that regulates B cell fate by controlling V(D)J recombination.
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Reed NP, Henderson MA, Oltz EM, Aune TM. Reciprocal regulation of Rag expression in thymocytes by the zinc-finger proteins, Zfp608 and Zfp609. Genes Immun 2012; 14:7-12. [PMID: 23076336 DOI: 10.1038/gene.2012.47] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Recombination-activating gene 1 (Rag1) and Rag2 enzymes are required for T cell receptor assembly and thymocyte development. The mechanisms underlying the transcriptional activation and repression of Rag1 and Rag2 are incompletely understood. The zinc-finger protein, Zfp608, represses Rag1 and Rag2 expression when expressed in thymocytes blocking T-cell maturation. Here we show that the related zinc-finger protein, Zfp609, is necessary for Rag1 and Rag2 expression in developing thymocytes. Zfp608 represses Rag1 and Rag2 expression indirectly by repressing the expression of Zfp609. Thus, the balance of Zfp608 and Zfp609 plays a critical role in regulating Rag1 and Rag2 expression, which may manifest itself not only during development of immature thymocytes into mature T cells but also in generation of the T-cell arm of the adaptive immune system, which does not fully develop until after birth.
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Affiliation(s)
- N P Reed
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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4
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Fenstermaker RA, Ciesielski MJ. EGFR Intron Recombination in Human Gliomas: Inappropriate Diversion of V(D)J Recombination? Curr Genomics 2011; 8:163-70. [PMID: 18645600 DOI: 10.2174/138920207780833838] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Revised: 02/26/2007] [Accepted: 03/26/2007] [Indexed: 12/25/2022] Open
Abstract
The epidermal growth factor receptor (EGFR) is a membrane-bound, 170 kDa, protein tyrosine kinase that plays an important role in tumorigenesis. The EGFR gene, which is composed of over 168 kb of sequence, including a 123-kb first intron, is frequently amplified and rearranged in malignant gliomas leading to the expression of oncogenic deletion (DM) and tandem duplication (TDM) mutants. The most common DM in gliomas is EGFRvIII, which arises from recombination between introns 1 and 7 with deletion of exons 2 through 7 and intervening introns. In addition, some human gliomas express 180- to 190-kDa TDM, which are constitutively active and highly oncogenic. Both DM and TDM arise by recombination of introns that contain sequences with homology to the recombination signal sequence (RSS) heptamers and nonamers present in the V(D)J region of the immunoglobin and T lymphocyte antigen receptor genes. V(D)J RSS have also been identified in certain proto-oncogenes like bcl-2 that are involved in translocations associated with the development of human lymphomas and in other genes such as hypoxanthine-guainine phosphoribosyl transferase (HPRT) in which deletion mutations and intron rearrangements are a common phenomenon. Together with the expression of recombination associated gene (RAG) and nonhomologous end-joining (NHEJ) proteins in gliomas, these observation suggest that aberrant activity of the V(D)J recombinase may be involved in the activation of proto-oncogenes in both liquid and solid tumors.
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Affiliation(s)
- Robert A Fenstermaker
- Department of Neurosurgery, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA
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Chen Z, Xiao Y, Zhang J, Li J, Liu Y, Zhao Y, Ma C, Luo J, Qiu Y, Huang G, Korteweg C, Gu J. Transcription factors E2A, FOXO1 and FOXP1 regulate recombination activating gene expression in cancer cells. PLoS One 2011; 6:e20475. [PMID: 21655267 PMCID: PMC3105062 DOI: 10.1371/journal.pone.0020475] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 04/26/2011] [Indexed: 02/05/2023] Open
Abstract
It has long been accepted that immunoglobulins (Igs) were produced by B lymphoid cells only. Recently Igs have been found to be expressed in various human cancer cells and promote tumor growth. Recombination activating gene 1 (RAG1) and RAG2, which are essential enzymes for initiating variable-diversity-joining segment recombination, have also been found to be expressed in cancer cells. However, the mechanism of RAG activation in these cancer cells has not been elucidated. Here, we investigated the regulatory mechanism of RAG expression in four human cancer cell lines by analyzing transcription factors that induce RAG activation in B cells. By RT-PCR, Western blot and immunofluorescence, we found that transcription factors E2A, FOXO1 and FOXP1 were expressed and localized to the nuclei of these cancer cells. Over-expression of E2A, FOXO1 or Foxp1 increased RAG expression, while RNA interference of E2A, FOXO1 or FOXP1 decreased RAG expression in the cancer cells. Chromatin immunoprecipitation experiments showed acetylation of RAG enhancer (Erag) and E2A, FOXO1 or FOXP1 were bound to Erag in vivo. These results indicate that in these cancer cells the transcription factors E2A, FOXO1 and FOXP1 regulate RAG expression, which initiates Ig gene rearrangement much in the way similar to B lymphocytes.
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Affiliation(s)
- Zhengshan Chen
- Department of Pathology, Shantou University Medical College, Shantou, China
| | - Yanna Xiao
- Department of Pathology, Shantou University Medical College, Shantou, China
| | - Junjun Zhang
- Department of Pathology, Shantou University Medical College, Shantou, China
| | - Jing Li
- Department of Pathology, Shantou University Medical College, Shantou, China
| | - Yuxuan Liu
- Department of Pathology, Peking (Beijing) University Health Science Center, Beijing, China
| | - Yingying Zhao
- Department of Pathology, Peking (Beijing) University Health Science Center, Beijing, China
| | - Changchun Ma
- Department of Pathology, Shantou University Medical College, Shantou, China
| | - Jin Luo
- Department of Pathology, Shantou University Medical College, Shantou, China
| | - Yamei Qiu
- Department of Pathology, Shantou University Medical College, Shantou, China
| | - Guowei Huang
- Department of Pathology, Shantou University Medical College, Shantou, China
| | - Christine Korteweg
- Department of Pathology, Shantou University Medical College, Shantou, China
| | - Jiang Gu
- Department of Pathology, Shantou University Medical College, Shantou, China
- Department of Pathology, Peking (Beijing) University Health Science Center, Beijing, China
- * E-mail:
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Kisielow P, Miazek A, Cebrat M. NWC, a new gene within RAG locus: could it keep GOD under control? Int J Immunogenet 2009; 35:395-9. [PMID: 18976445 DOI: 10.1111/j.1744-313x.2008.00791.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
NWC, newly discovered, evolutionarily conserved gene within recombination activating gene (RAG) locus is constitutively expressed in all cells except lymphocytes, in which it is developmentally regulated by RAG1 promoter. In lymphocytes, NWC promoter, which is located within RAG2 intron and drives expression of NWC in non-lymphocytes, is inactive. Here, a hypothesis on the role of transcription of NWC in lymphocyte-specific regulation of RAG expression and their suppression in all other cells is presented. It is proposed that during development, inactivation of NWC promoter and the placement of NWC under the control of RAG1 promoter releases RAG genes from permanent suppression and allows their lymphocyte specific expression but at the same time subjects them to transcriptional feedback inhibition type of suppression which could permit for a stringent control over their threat to genome stability and oncogenic potential.
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Affiliation(s)
- P Kisielow
- Department of Tumor Immunology, Laboratory of Transgenesis and Lymphocyte Biology, Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland.
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Chen Z, Qiu X, Gu J. Immunoglobulin expression in non-lymphoid lineage and neoplastic cells. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 174:1139-48. [PMID: 19246641 DOI: 10.2353/ajpath.2009.080879] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
It has traditionally been believed that the production of immunoglobulin (Ig) molecules is restricted to B lineage cells. However, immunoglobulin genes and proteins have been recently found in a variety of types of cancer cells, as well as some proliferating epithelial cells and neurons. The immunoglobulin molecules expressed by these cells consist predominantly of IgG, IgM, and IgA, and the light chains expressed are mainly kappa chains. Recombination activating genes 1 and 2, which are required for V(D)J recombination, are also expressed in these cells. Knowledge about the function of these non-lymphoid cell-derived immunoglobulins is limited. Preliminary data suggests that Ig secreted by epithelial cancer cells has some unidentified capacity to promote the growth and survival of tumor cells. As immunoglobulins are known to have a wide spectrum of important functions, the discovery of non-lymphoid cells and cancers that produce immunoglobulin calls for in-depth investigation of the functional and pathological significance of this previously unrecognized phenomenon.
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Affiliation(s)
- Zhengshan Chen
- Department of Pathology, Peking (Beijing) University Health Science Center, China
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Regulation of B cell fate commitment and immunoglobulin heavy-chain gene rearrangements by Ikaros. Nat Immunol 2008; 9:927-36. [PMID: 18568028 DOI: 10.1038/ni.1626] [Citation(s) in RCA: 201] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2008] [Accepted: 05/23/2008] [Indexed: 12/11/2022]
Abstract
The transcription factor Ikaros is essential for B cell development. However, its molecular functions in B cell fate specification and commitment have remained elusive. We show here that the transcription factor EBF restored the generation of CD19(+) pro-B cells from Ikaros-deficient hematopoietic progenitors. Notably, these pro-B cells, despite having normal expression of the transcription factors EBF and Pax5, were not committed to the B cell fate. They also failed to recombine variable gene segments at the immunoglobulin heavy-chain locus. Ikaros promoted heavy-chain gene rearrangements by inducing expression of the recombination-activating genes as well as by controlling accessibility of the variable gene segments and compaction of the immunoglobulin heavy-chain locus. Thus, Ikaros is an obligate component of a network that regulates B cell fate commitment and immunoglobulin heavy-chain gene recombination.
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Sobacchi C, Marrella V, Rucci F, Vezzoni P, Villa A. RAG-dependent primary immunodeficiencies. Hum Mutat 2006; 27:1174-84. [PMID: 16960852 DOI: 10.1002/humu.20408] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mutations in recombination activating genes 1 and 2 (RAG1 and RAG2) cause a spectrum of severe immunodeficiencies ranging from classical T cell-B cell-severe combined immunodeficiency (T(-)B(-)SCID) and Omenn syndrome (OS) to an increasing number of peculiar cases. While it is well established from biochemical data that the specific genetic defect in either of the RAG genes is the first determinant of the clinical presentation, there is also increasing evidence that environmental factors play an important role and can lead to a different phenotypic expression of a given genotype. However, a better understanding of the mechanisms by which the molecular defect impinges on the cellular phenotype of OS is still lacking. Ongoing studies in knock-in mice could better clarify this aspect.
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10
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Zhang F, Thomas LR, Oltz EM, Aune TM. Control of thymocyte development and recombination-activating gene expression by the zinc finger protein Zfp608. Nat Immunol 2006; 7:1309-16. [PMID: 17057722 DOI: 10.1038/ni1397] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Accepted: 08/25/2006] [Indexed: 01/31/2023]
Abstract
The products of recombination-activating gene 1 (Rag1) and Rag2 are required for T cell receptor gene assembly and thymocyte maturation, yet their transcriptional control mechanisms remain unclear. A congenic strain (called 'ZORI' here) with defects in Rag1 and Rag2 expression, thymocyte maturation and peripheral T cell homeostasis has been developed. Here, we mapped the mutation in this strain to a chromosome 18 locus containing a single known gene encoding the zinc finger protein Zfp608. This gene (Zfp608) was highly expressed in neonatal thymus but was extinguished thereafter. In contrast to wild-type mice, ZORI mice had sustained thymocyte expression of Zfp608 throughout life. The ZORI mutation produced a thymocyte-intrinsic developmental defect. Overexpression of Zfp608 in BALB/c thymocytes substantially impaired Rag1 and Rag2 expression, indicating the underlying mechanism for the defect in ZORI thymocyte development. Thus, the normal function of Zfp608 may be to prevent Rag1 and Rag2 expression in utero.
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Affiliation(s)
- Feng Zhang
- Division of Rheumatology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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11
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Abstract
Transcriptional regulation of T-cell development involves successive interactions between complexes of transcriptional regulators and their binding sites within the regulatory regions of each gene. The regulatory modules that control expression of T-lineage genes frequently include binding sites for a core set of regulators that set the T-cell-specific background for signal-dependent control, including GATA-3, Notch/CSL, c-myb, TCF-1, Ikaros, HEB/E2A, Ets, and Runx factors. Additional regulators in early thymocytes include PU.1, Id-2, SCL, Spi-B, Erg, Gfi-1, and Gli. Many of these factors are involved in simultaneous regulation of non-T-lineage genes, T-lineage genes, and genes involved in cell cycle control, apoptosis, or survival. Potential and known interactions between early thymic transcription factors such as GATA-3, SCL, PU.1, Erg, and Spi-B are explored. Regulatory modules involved in the expression of several critical T-lineage genes are described, and models are presented for shifting occupancy of the DNA-binding sites in the regulatory modules of pre-Talpha, T-cell receptor beta (TCRbeta), recombinase activating genes 1 and 2 (Rag-1/2), and CD4 during T-cell development. Finally, evidence is presented that c-kit, Erg, Hes-1, and HEBAlt are expressed differently in Rag-2(-/-) thymocytes versus normal early thymocytes, which provide insight into potential regulatory interactions that occur during normal T-cell development.
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Affiliation(s)
- Michele K Anderson
- Sunnybrook and Women's College Health Sciences Center, Division of Molecular and Cell Biology, University of Toronto, Department of Immunology, Toronto, ON, Canada.
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12
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Labrie JE, Borghesi L, Gerstein RM. Bone marrow microenvironmental changes in aged mice compromise V(D)J recombinase activity and B cell generation. Semin Immunol 2005; 17:347-55. [PMID: 15963731 DOI: 10.1016/j.smim.2005.05.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
B cell generation and immunoglobulin (Ig) diversity in mice is compromised with aging. Our recent work sought to understand mechanism(s) that contribute to reduced B cell production in aged mice. Using in vivo labeling, we found that reduction in marrow pre-B cells reflects increased attrition during passage from the pro-B to pre-B cell pool. Analyses of reciprocal bone marrow (BM) chimeras reveal that the production rates of pre-B cells are controlled primarily by microenvironmental factors, rather than intrinsic events. To understand changes in pro-B cells that could diminish production of pre-B cells, we evaluated rag2 expression and V(D)J recombinase activity in pro-B cells at the single cell level. The percentage of pro-B cells that express rag2 is reduced in aged mice and is correlated with both a loss of V(D)J recombinase activity in pro-B cells and reduced numbers of pre-B cells. Reciprocal BM chimeras revealed that the aged microenvironment also determines rag2 expression and recombinase activity in pro-B cells. These observations suggest that extrinsic factors in the BM that decline with age are largely responsible for less efficient V(D)J recombination in pro-B cells and diminished progression to the pre-B cell stage. These extrinsic factors may include cytokines and chemokines derived from BM stromal cells that are essential to the development of B cell precursors. The changes during aging within the BM hematopoietic microenvironment most likely are linked to the physiology of aging bone. Bone degrades with age (osteoporosis) due to decreased formation of new bone by osteoblasts. Marrow stem cells (MSC) are considered the progenitor of both adipocytes, osteoblasts and hematopoietic stromal cells and a controlled reciprocal regulation exists of osteoblast versus adipocyte differentiation; with age adipocytes increase, and osteoblast decrease. It is possible that stromal cell generation from MSC is compromised during aging. Currently, understanding of BM microenvironmental factors that regulate rag gene expression is very limited. However, as early progenitors differentiate, it is increasing clear that a limited set of transcription factors (e.g. ikaros, PU.1, E2A, EBF, pax5) regulate B-lineage specific genes, and that expression and stability of these factors is responsive to the microenvironment. Current and future work by several groups will strive to understand mechanisms that regulate these factors and how aging impacts these regulatory circuits.
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Affiliation(s)
- Joseph E Labrie
- Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655, USA
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13
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Cebrat M, Miazek A, Kisielow P. Identification of a third evolutionarily conserved gene within the RAG locus and its RAG1-dependent and -independent regulation. Eur J Immunol 2005; 35:2230-8. [PMID: 15971274 DOI: 10.1002/eji.200526225] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Recombination-activating gene (RAG)1 and RAG2 encode T and B lymphocyte-specific endonucleases indispensable for rearrangements of antigen-receptor gene segments but also capable of causing deleterious chromosome rearrangements. The mechanisms regulating RAG expression and repression are not clear. Here we identify NWC, a third evolutionarily conserved gene within the RAG locus, and show that it is ubiquitously expressed, with the notable exception of RAG-nonexpressing immature and mature T and B lymphocytes because in lymphocytes it is regulated by the RAG1 promoter and transcribed as RAG1-NWC hybrid mRNA molecules. We also show that in all other cells NWC is controlled by the RAG2 intragenic promoter, which in immature and mature T and B lymphocytes is silent. The possible implications of these findings for understanding the activation and inactivation of RAG genes in lymphocytes and their repression in other cells are discussed.
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Affiliation(s)
- Malgorzata Cebrat
- Department of Tumor Immunology, Laboratory of Transgenesis and Lymphocyte Biology, Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
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Verkoczy L, Aїt-Azzouzene D, Skog P, Märtensson A, Lang J, Duong B, Nemazee D. A role for nuclear factor kappa B/rel transcription factors in the regulation of the recombinase activator genes. Immunity 2005; 22:519-31. [PMID: 15845455 PMCID: PMC3792720 DOI: 10.1016/j.immuni.2005.03.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2004] [Revised: 03/04/2005] [Accepted: 03/16/2005] [Indexed: 01/25/2023]
Abstract
In developing B cells, expression of surface immunoglobulin is an important signal to terminate recombinase activator gene (RAG) expression and V(D)J recombination. However, autoreactive antigen receptors instead promote continued gene rearrangement and receptor editing. The regulation by B cell receptor (BCR) signaling of RAG expression and editing is poorly understood. We report that in editing-competent cells BCR ligand-induced RAG mRNA expression is regulated at the level of RAG transcription, rather than mRNA stability. In immature B cells carrying innocuous receptors, RAG expression appears to be under rapidly reversible negative regulation. Studies involving transduction of a superrepressive (sr) I kappa B alpha protein indicate that NF-kappaB/Rel proteins promote RAG transcription. Interestingly, NF kappa B1-deficient cells overexpress RAG and undergo an exaggerated receptor editing response. Our data implicate NF kappa B transcription factors in the BCR-mediated regulation of RAG locus transcription. Rapidly activated NF kappa B pathways may facilitate prompt antigen receptor-regulated changes in RAG expression important for editing and haplotype exclusion.
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Affiliation(s)
- Laurent Verkoczy
- Department of Immunology The Scripps Research Institute La Jolla, California 92037
| | - Djemel Aїt-Azzouzene
- Department of Immunology The Scripps Research Institute La Jolla, California 92037
| | - Patrick Skog
- Department of Immunology The Scripps Research Institute La Jolla, California 92037
| | - Annica Märtensson
- Department of Immunology The Scripps Research Institute La Jolla, California 92037
| | - Julie Lang
- Barbara Davis Center 4200 East Ninth Avenue Denver, Colorado 80262
| | - Bao Duong
- Department of Immunology The Scripps Research Institute La Jolla, California 92037
- The Kellogg School of Science and Technology, Doctoral Program in Chemical and Biological Sciences, The Scripps Research Institute, La Jolla, California 92037
| | - David Nemazee
- Department of Immunology The Scripps Research Institute La Jolla, California 92037
- Barbara Davis Center 4200 East Ninth Avenue Denver, Colorado 80262
- Correspondence:
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15
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Wei XC, Dohkan JI, Kishi H, Wu CX, Kondo S, Muraguchi A. Characterization of the proximal enhancer element and transcriptional regulatory factors for murine recombination activating gene-2. Eur J Immunol 2005; 35:612-21. [PMID: 15657951 DOI: 10.1002/eji.200425185] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Recombination-activating gene (RAG)-1 and RAG-2 are essential for V(D)J recombination and are expressed specifically in lymphoid cells. We previously identified two putative enhancer elements, the proximal and distal enhancers, located at -2.6 and -8 kb, respectively, 5' upstream of mouse RAG-2, and characterized the distal enhancer element in detail. In this study, to characterize the proximal enhancer in vitro as well as in vivo, we first defined a 170-bp core enhancer element within the proximal enhancer (Ep) and determined its activity in various cells. Ep conferred enhancer activity only in B-lymphoid cell lines, but not in T- or non-lymphoid cell lines. Analysis of the transgenic mice carrying an EGFP reporter gene linked with Ep revealed that Ep activated the transcription of the reporter gene in bone marrow and spleen, but not in thymus or non-lymphoid tissues. Ep was active in both B220+IgM- and B220+IgM+ subpopulations in the bone marrow and in the B220+ subpopulation in the spleen. Using electrophoretic mobility shift assays and mutational assays, we found that Ikaros and CCAAT/enhancer binding protein cooperatively bind Ep and function as the transcription factors responsible for B cell-specific enhancer activity. These results demonstrate the role of Ep as a cis-regulatory enhancer element for RAG-2-specific expression in B-lymphoid lineages.
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Affiliation(s)
- Xing-Cheng Wei
- Department of Immunology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Sugitani, Toyama, Japan
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16
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Abstract
Autoreactive antibodies are etiologic agents in a number of autoimmune diseases. Like all other antibodies these antibodies are produced in developing B cells by V(D)J recombination in the bone marrow. Three mechanisms regulate autoreactive B cells: deletion, receptor editing, and anergy. Here we review the prevalence of autoantibodies in the initial antibody repertoire, their regulation by receptor editing, and the role of the recombinase proteins (RAG1 and RAG2) in this process.
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Affiliation(s)
- Mila Jankovic
- Laboratory of Molecular Immunology, The Rockefeller University, New York, New York 10021, USA.
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Wu CX, Zhao WP, Kishi H, Dokan J, Jin ZX, Wei XC, Yokoyama KK, Muraguchi A. Activation of mouse RAG-2 promoter by Myc-associated zinc finger protein. Biochem Biophys Res Commun 2004; 317:1096-102. [PMID: 15094381 DOI: 10.1016/j.bbrc.2004.03.159] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2004] [Indexed: 11/24/2022]
Abstract
Recombination activating gene-1 (RAG-1) and RAG-2 are expressed specifically in lymphocytes undergoing the antigen receptor gene rearrangement during the lymphocyte development. Our previous study showed that the -41 to -17 nucleotides (nt) 5' -upstream region of mouse RAG-2 were pre-requisite for the core promoter activity and that Pax-5/c-Myb/LEF-1 protein-protein complex was responsible for its activity in immature B cells. In this study, we show that the -65/-42 sequence, the non-conserved sequence between human and mouse RAG-2 promoter, is necessary for the full promoter activity for mouse RAG-2. Electrophoresis mobility shift assay revealed that Myc-associated zinc finger protein (MAZ) as well as SP1/3 binds a GA box in this region. Using chromatin immunoprecipitation, we show that MAZ binds the RAG-2 promoter region in pre-B cells. Furthermore, we show that MAZ synergistically activates the murine RAG-2 promoter with Pax-5/c-Myb/LEF-1 complex. These results first demonstrate that MAZ participates in activation of mouse RAG-2 promoter.
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Affiliation(s)
- Chun-Xiao Wu
- Department of Immunology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, 2630, Sugitani, Toyama 930-0194, Japan
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18
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Bartholdy B, Matthias P. Transcriptional control of B cell development and function. Gene 2004; 327:1-23. [PMID: 14960357 DOI: 10.1016/j.gene.2003.11.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2003] [Revised: 10/14/2003] [Accepted: 11/07/2003] [Indexed: 12/17/2022]
Abstract
The generation, development, maturation and selection of mammalian B lymphocytes is a complex process that is initiated in the embryo and proceeds throughout life to provide the organism an essential part of the immune system it requires to cope with pathogens. Transcriptional regulation of this highly complex series of events is a major control mechanism, although control is also exerted on all other layers, including splicing, translation and protein stability. This review summarizes our current understanding of transcriptional control of the well-studied murine B cell development, which bears strong similarity to its human counterpart. Animal and cell models with loss of function (gene "knock outs") or gain of function (often transgenes) have significantly contributed to our knowledge about the role of specific transcription factors during B lymphopoiesis. In particular, a large number of different transcriptional regulators have been linked to distinct stages of the life of B lymphocytes such as: differentiation in the bone marrow, migration to the peripheral organs and antigen-induced activation.
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Affiliation(s)
- Boris Bartholdy
- Friedrich Miescher Institute for Biomedical Research, Novartis Research Foundation, PO Box 2543, Maulbeerstrasse 66, 4058 Basel, Switzerland
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19
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Yannoutsos N, Barreto V, Misulovin Z, Gazumyan A, Yu W, Rajewsky N, Peixoto BR, Eisenreich T, Nussenzweig MC. A cis element in the recombination activating gene locus regulates gene expression by counteracting a distant silencer. Nat Immunol 2004; 5:443-50. [PMID: 15021880 DOI: 10.1038/ni1053] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2004] [Accepted: 01/22/2004] [Indexed: 12/22/2022]
Abstract
We have identified a silencer and an antisilencing element that interact at a distance of 85 kilobases to regulate expression of the recombination activating genes Rag1 and Rag2 in thymocytes. Transgenic experiments showed that Rag promoter-proximal cis elements directed tissue-specific expression and that a Runx-dependent intergenic silencer suppressed expression in developing T cells. Deletion of the antisilencing element from the genomic Rag locus unmasked the intergenic silencer and abrogated Rag expression in developing CD4(+)CD8(+) T cells. We speculate that the Rag antisilencing element belongs to a class of cis elements that might be useful for genome diversification by activating genes encoded by otherwise silent transposable elements.
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Affiliation(s)
- Nikos Yannoutsos
- Laboratory of Molecular Immunology, Rockefeller University, New York, New York 10021, USA.
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20
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Affiliation(s)
- Mark S Schlissel
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA.
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21
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Leider N, Melamed D. Differential c-Myc responsiveness to B cell receptor ligation in B cell-negative selection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:2446-52. [PMID: 12928392 DOI: 10.4049/jimmunol.171.5.2446] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Responsiveness of c-Myc oncogene to B cell receptor ligation has been implicated in the induction of apoptosis in transformed and normal immature B cells. These studies provided compelling evidence to link the c-Myc oncogene with the process of negative selection in B-lymphocytes. However, in addition to apoptosis, B cell-negative selection has been shown to occur by secondary Ig gene rearrangements, a mechanism called receptor editing. In this study, we assessed whether differential c-Myc responsiveness to B cell receptor (BCR) ligation is associated with the mechanism of negative selection in immature B cells. Using an in vitro bone marrow culture system and an Ig-transgenic mouse model (3-83) we show here that c-Myc is expressed at low levels throughout B cell development and that c-Myc responsiveness to BCR ligation is developmentally regulated and increased with maturation. Furthermore, we found that the competence to mount c-Myc responsiveness upon BCR ligation is important for the induction of apoptosis and had no effect on the process of receptor editing. Therefore, this study suggests an important role of c-Myc in promoting and/or maintaining B cell development and that compartmentalization of B cell tolerance may also be developmentally regulated by differential c-Myc responsiveness.
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MESH Headings
- Animals
- Antigens, CD19/genetics
- Apoptosis/genetics
- Apoptosis/immunology
- B-Lymphocyte Subsets/cytology
- B-Lymphocyte Subsets/immunology
- B-Lymphocyte Subsets/metabolism
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Cell Line, Transformed
- Cells, Cultured
- DNA-Binding Proteins/biosynthesis
- Gene Expression Regulation/immunology
- Genes, myc/immunology
- Ligands
- Lymphopoiesis/genetics
- Lymphopoiesis/immunology
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Oligonucleotides, Antisense/pharmacology
- Proto-Oncogene Proteins c-myc/biosynthesis
- Proto-Oncogene Proteins c-myc/genetics
- RNA Editing/genetics
- RNA Editing/immunology
- Receptors, Antigen, B-Cell/immunology
- Receptors, Antigen, B-Cell/metabolism
- Receptors, Antigen, B-Cell/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- Self Tolerance/genetics
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Affiliation(s)
- Nira Leider
- Department of Immunology, Technion Faculty of Medicine, Haifa 31096, Israel
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22
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Hsu LY, Lauring J, Liang HE, Greenbaum S, Cado D, Zhuang Y, Schlissel MS. A conserved transcriptional enhancer regulates RAG gene expression in developing B cells. Immunity 2003; 19:105-17. [PMID: 12871643 DOI: 10.1016/s1074-7613(03)00181-x] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although expression of the RAG1 and RAG2 genes is essential for lymphocyte development, the mechanisms responsible for the lymphoid- and developmental stage-specific regulation of these genes are poorly understood. We have identified a novel, evolutionarily conserved transcriptional enhancer in the RAG locus, called Erag, which was essential for the expression of a chromosomal reporter gene driven by either RAG promoter. Targeted deletion of Erag in the mouse germline results in a partial block in B cell development associated with deficient V(D)J recombination, whereas T cell development appears unaffected. We found that E2A transcription factors bind to Erag in vivo and can transactivate Erag-dependent reporter constructs in cotransfected cell lines. These findings lead us to conclude that RAG transcription is regulated by distinct elements in developing B and T cells and that Erag is required for optimal levels of RAG expression in early B cell precursors but not in T cells.
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Affiliation(s)
- Lih-Yun Hsu
- Division of Immunology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
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23
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Jin ZX, Kishi H, Wei XC, Matsuda T, Saito S, Muraguchi A. Lymphoid Enhancer-Binding Factor-1 Binds and Activates the Recombination-Activating Gene-2 Promoter Together with c-Myb and Pax-5 in Immature B Cells. THE JOURNAL OF IMMUNOLOGY 2002; 169:3783-92. [PMID: 12244173 DOI: 10.4049/jimmunol.169.7.3783] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The recombination-activating gene (RAG)-1 and RAG-2 are expressed specifically in immature lymphoid cells undergoing the recombination of Ag receptor genes. We studied the regulation of murine RAG-2 promoter and revealed that -41/-17 RAG-2 promoter region, which was indispensable for the RAG-2 promoter activity in B cell lines, contained binding sites for lymphoid enhancer-binding factor-1 (LEF-1), c-Myb, and Pax-5. We showed that these three transcription factors bound the promoter region in vitro and in vivo. Cotransfection assays using a human embryonic kidney cell line (293T) showed that LEF-1, c-Myb, and Pax-5 cooperatively activated the RAG-2 promoter, via their synergistic DNA binding. We also showed that LEF-1, c-Myb, and Pax-5 physically interact in the cells. Finally, we demonstrated that a dominant-negative LEF-1 protein, which lacks the binding site for beta-catenin, suppressed the RAG-2 promoter activity as well as the endogenous RAG-2 expression in a pre-B cell line (18.81). These results suggest that LEF-1/beta-catenin complex regulates the RAG-2 promoter activation in concert with c-Myb and Pax-5 in immature B cells. The link between LEF-1/beta-catenin and Wnt signaling in B lineage cells will be discussed.
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Affiliation(s)
- Zhe-Xiong Jin
- Department of Immunology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Sugitani, Toyama, Japan
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24
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Boudarra N, Frippiat C, Dournon C, Frippiat JP. An alternative internal splicing site defines new Ikaros isoforms in Pleurodeles waltl. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2002; 26:659-673. [PMID: 12074930 DOI: 10.1016/s0145-305x(02)00014-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The Ikaros gene encodes a family of transcription factors which plays a crucial role in hematopoiesis. To improve our knowledge about the immune system of Pleurodeles waltl, we sequenced the cDNA coding for the Ik-1 isoform of that salamander and analyzed its tissue expression by semi-quantitative RT-PCR. Ikaros transcripts are abundant in the thymus and the spleen, thereby confirming that these organs are, respectively, the primary and secondary lymphoid tissues of Pleurodeles. Analysis of the isoforms produced by this animal revealed two isoforms characteristic of amphibians in which an alternative internal splicing site deletes the 3' half of exon 3 which interestingly comprises the first Zn finger of Ikaros. Ikaros transcripts were found at the earliest stages of development of Pleurodeles indicating that Ikaros has a function at the very early lymphopoietic stages. Moreover, the presence of Ikaros transcripts in spermatozoa suggests that this protein could have another and yet unknown function.
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Affiliation(s)
- Najia Boudarra
- Laboratoire de Biologie Expérimentale et Immunologie, UPRES EA 2401, Université Henri Poincaré, Nancy 1, Boulevard des Aiguillettes, BP 239, F-54506 Vandoeuvre-lès-Nancy Cedex, France
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25
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Munthe E, Aasheim HC. Characterization of the human ephrin-A4 promoter. Biochem J 2002; 366:447-58. [PMID: 12030849 PMCID: PMC1222801 DOI: 10.1042/bj20011693] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2001] [Revised: 04/19/2002] [Accepted: 05/24/2002] [Indexed: 01/25/2023]
Abstract
Expression of the ephrin-A4 ligand, a family member of ligands binding the Eph receptor tyrosine kinases, is induced after an antigen-receptor stimulation of lymphocytes. To understand the transcription regulation of the ephrin-A4 gene, its promoter was identified and regulating elements were characterized. The ephrin-A4 promoter contains cis elements directing the cell-specific expression. By deletion studies, three specific regions, which were contributing to the transcription activity in lymphoid cells, were localized. In one of these regions, an inverted CCAAT box was identified and shown to bind the transcription activator nuclear factor-Y (NF-Y). The importance of NF-Y binding for the ephrin-A4 promoter activity is shown by a total abrogation of promoter activity after destruction of its binding site. NF-Y binding and activity are also crucially dependent on the integrity of the surrounding sequence. In addition, electrophoretic mobility-shift assay and serial-mutation analysis of the two remaining regulating regions revealed cis regulatory elements contributing to the transcription activity of the ephrin-A4 promoter.
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Affiliation(s)
- Else Munthe
- Department of Immunology, The Norwegian Radium Hospital, Montebello, N-0310 Oslo, Norway.
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26
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Wei XC, Kishi H, Jin ZX, Zhao WP, Kondo S, Matsuda T, Saito S, Muraguchi A. Characterization of chromatin structure and enhancer elements for murine recombination activating gene-2. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:873-81. [PMID: 12097391 DOI: 10.4049/jimmunol.169.2.873] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Recombination-activating genes (RAGs) play a critical role in V(D)J recombination machinery and their expression is specifically regulated during lymphocyte ontogeny. To elucidate the molecular mechanisms regulating murine RAG-2 expression, we examined a chromatin structure of 25-kb DNA segment adjacent to murine RAG-2 by analyzing DNase I hypersensitive (HS) sites. In a RAG-2-expressing murine pre-B cell line, three lymphoid cell-specific HS sites (HS1, HS2, and HS3) were identified. Among these HS sites, one HS site (HS3) that locates in the RAG-2 promoter was associated only with RAG-2-expressing cell lines. Using the transient enhanced green fluorescence protein reporter gene assays, we identified two enhancer elements in the 5'-upstream region of RAG-2 that corresponded to HS1 and HS2. One of the enhancer elements (D3) exhibited enhancer activity only in the lymphoid cell lines. Analysis of the transgenic mice carrying the enhanced green fluorescence protein-reporter gene linked with D3 revealed that D3 activated the reporter gene-expression in the primary lymphoid tissues, but not in the secondary lymphoid tissues or nonlymphoid tissues. D3 was active in CD4(-)CD8(-), but not in CD4(+)CD8(+) or CD4(+)CD8(-) thymocytes in the thymus, and also active in B220(+)IgM(-), but not in B220(+)IgM(+), cells in the bone marrow. Finally, our data suggested that C/EBP may bind to the D3 enhancer and function as one of the transcription factor(s) responsible for the enhancer activity. These results show that the tissue- and stage-specific expression of murine RAG-2 is regulated by alteration of the chromatin structure as well as cis-regulatory enhancer elements.
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Affiliation(s)
- Xing-Cheng Wei
- Department of Immunology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Sugitani, Toyama, Japan
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27
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Girschick HJ, Grammer AC, Nanki T, Vazquez E, Lipsky PE. Expression of recombination activating genes 1 and 2 in peripheral B cells of patients with systemic lupus erythematosus. ARTHRITIS AND RHEUMATISM 2002; 46:1255-63. [PMID: 12115231 DOI: 10.1002/art.10264] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
OBJECTIVE To analyze immunoregulatory abnormalities in patients with systemic lupus erythematosus (SLE) by assessing the expression of messenger RNA (mRNA) for types 1 and 2 recombination activating genes (RAG) in the peripheral blood of patients with active SLE. METHODS We examined B cell populations and also individual B cells from patients with SLE for the expression of RAG mRNA. RESULTS Analysis of bulk mRNA indicated that RAG1 and RAG2 mRNA were found routinely in peripheral B cells of patients with active SLE, but not in healthy subjects. When assessed on a single-cell basis, there was a 3-fold increase in the frequency of RAG1- and RAG2-expressing B cells in SLE patients compared with healthy subjects. Notably, B cells expressing both RAG1 and RAG2 mRNA expressed only IgD mRNA, but not IgG mRNA. Fifty percent of RAG-expressing B cells also expressed VpreB mRNA, whereas all expressed CD154 mRNA. Phenotypic analysis indicated that RAG-expressing B cells were activated, mature B cells. CONCLUSION These results indicate that RAG expression is up-regulated in peripheral IgD+ and VpreB+ B cells of patients with active SLE. These cells may contribute to the immunoregulatory abnormalities in patients with SLE.
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28
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Carleton M, Haks MC, Smeele SAA, Jones A, Belkowski SM, Berger MA, Linsley P, Kruisbeek AM, Wiest DL. Early growth response transcription factors are required for development of CD4(-)CD8(-) thymocytes to the CD4(+)CD8(+) stage. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:1649-58. [PMID: 11823493 DOI: 10.4049/jimmunol.168.4.1649] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Progression of immature CD4(-)CD8(-) thymocytes beyond the beta-selection checkpoint to the CD4(+)CD8(+) stage requires activation of the pre-TCR complex; however, few of the DNA-binding proteins that serve as molecular effectors of those pre-TCR signals have been identified. We demonstrate in this study that members of the early growth response (Egr) family of transcription factors are critical effectors of the signals that promote this developmental transition. Specifically, the induction of three Egr family members (Egr1, 2, and 3) correlates with pre-TCR activation and development of CD4(-)CD8(-) thymocytes beyond the beta-selection checkpoint. Enforced expression of each of these Egr factors is able to bypass the block in thymocyte development associated with defective pre-TCR function. However, Egr family members may play somewhat distinct roles in promoting thymocyte development, because there are differences in the genes modulated by enforced expression of particular Egr factors. Finally, interfering with Egr function using dominant-negative proteins disrupts thymocyte development from the CD4(-)CD8(-) to the CD4(+)CD8(+) stage. Taken together, these data demonstrate that the Egr proteins play an essential role in executing the differentiation program initiated by pre-TCR signaling.
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Affiliation(s)
- Michael Carleton
- Immunobiology Working Group, Division of Basic Sciences, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
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29
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Kishi H, Jin ZX, Wei XC, Nagata T, Matsuda T, Saito S, Muraguchi A. Cooperative binding of c-Myb and Pax-5 activates the RAG-2 promoter in immature B cells. Blood 2002; 99:576-83. [PMID: 11781241 DOI: 10.1182/blood.v99.2.576] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The recombination activating gene-1 (RAG-1) and RAG-2 are expressed specifically in immature lymphoid cells undergoing the recombination of antigen receptor genes. The regulation of murine RAG-2 promoter was studied and it was revealed that the -41/-17 RAG-2 promoter region, which is conserved between humans and mice, was indispensable for the RAG-2 promoter activity in B-cell lines. The region contained 2 cis elements that bound c-Myb and Pax-5. Mutation in the c-Myb-binding site in the promoter reduced the promoter activity in B-cell lines. Cooperative activation of the RAG-2 promoter was seen by a combination of c-Myb and Pax-5 in a human embryonic kidney cell line (293T), via their synergistic DNA-binding. Deletion experiments showed that the C-terminus of c-Myb was responsible for their interaction. Furthermore, the dominant-negative c-Myb mutant suppressed the activation of the RAG-2 promoter in a pre-B-cell line as well as in 293T cells. These results suggest that cooperative binding of c-Myb and Pax-5 to the RAG-2 promoter is one of the mechanisms to direct the restricted expression of the RAG-2 in immature B cells.
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Affiliation(s)
- Hiroyuki Kishi
- Department of Immunology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Sugitani, Toyama, Japan
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30
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Barreda DR, Belosevic M. Transcriptional regulation of hemopoiesis. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2001; 25:763-789. [PMID: 11602195 DOI: 10.1016/s0145-305x(01)00035-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The regulation of blood cell formation, or hemopoiesis, is central to the replenishment of mature effector cells of innate and acquired immune responses. These cells fulfil specific roles in the host defense against invading pathogens, and in the maintenance of homeostasis. The development of hemopoietic cells is under stringent control from extracellular and intracellular stimuli that result in the activation of specific downstream signaling cascades. Ultimately, all signal transduction pathways converge at the level of gene expression where positive and negative modulators of transcription interact to delineate the pattern of gene expression and the overall cellular hemopoietic response. Transcription factors, therefore, represent a nodal point of hemopoietic control through the integration of the various signaling pathways and subsequent modulation of the transcriptional machinery. Transcription factors can act both positively and negatively to regulate the expression of a wide range of hemopoiesis-relevant genes including growth factors and their receptors, other transcription factors, as well as various molecules important for the function of developing cells. The expression of these genes is dependent on the complex interactions between transcription factors, co-regulatory molecules, and specific binding sequences on the DNA. Recent advances in various vertebrate and invertebrate systems emphasize the importance of transcription factors for hemopoiesis control and the evolutionary conservation of several of such mechanisms. In this review we outline some of the key issues frequently identified in studies of the transcriptional regulation of hemopoietic gene expression. In teleosts, we expect that the characterization of several of these transcription factors and their regulatory mechanisms will complement recent advances in a number of fish systems where identification of cytokine and other hemopoiesis-relevant factors are currently under investigation.
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Affiliation(s)
- D R Barreda
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9
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31
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Yannoutsos N, Wilson P, Yu W, Chen HT, Nussenzweig A, Petrie H, Nussenzweig MC. The role of recombination activating gene (RAG) reinduction in thymocyte development in vivo. J Exp Med 2001; 194:471-80. [PMID: 11514603 PMCID: PMC2193494 DOI: 10.1084/jem.194.4.471] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Assembly of T cell receptor (TCR)alpha/beta genes by variable/diversity/joining (V[D]J) rearrangement is an ordered process beginning with recombination activating gene (RAG) expression and TCRbeta recombination in CD4(-)CD8(-)CD25(+) thymocytes. In these cells, TCRbeta expression leads to clonal expansion, RAG downregulation, and TCRbeta allelic exclusion. At the subsequent CD4(+)CD8(+) stage, RAG expression is reinduced and V(D)J recombination is initiated at the TCRalpha locus. This second wave of RAG expression is terminated upon expression of a positively selected alpha/beta TCR. To examine the physiologic role of the second wave of RAG expression, we analyzed mice that cannot reinduce RAG expression in CD4(+)CD8(+) T cells because the transgenic locus that directs RAG1 and RAG2 expression in these mice is missing a distal regulatory element essential for reinduction. In the absence of RAG reinduction we find normal numbers of CD4(+)CD8(+) cells but a 50-70% reduction in the number of mature CD4(+)CD8(-) and CD4(-)CD8(+) thymocytes. TCRalpha rearrangement is restricted to the 5' end of the Jalpha cluster and there is little apparent secondary TCRalpha recombination. Comparison of the TCRalpha genes expressed in wild-type or mutant mice shows that 65% of all alpha/beta T cells carry receptors that are normally assembled by secondary TCRalpha rearrangement. We conclude that RAG reinduction in CD4(+)CD8(+) thymocytes is not required for initial TCRalpha recombination but is essential for secondary TCRalpha recombination and that the majority of TCRalpha chains expressed in mature T cells are products of secondary recombination.
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Affiliation(s)
- N Yannoutsos
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10021, USA.
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32
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Abstract
Expression of T-cell receptor and surface immunoglobulins on T and B lymphocytes, respectively, is strictly dependent on the variable, (diversity) joining exon (V(D)J) recombination process, which is initiated by the lymphoid-specific recombinase activating gene proteins 1 and 2 (RAG1 and RAG2). Recent advances have highlighted the functional organization of the RAG1 and RAG2 proteins and have provided important information on the regulation of RAG gene expression. Depending on the severity of their effects on the V(D)J recombination process, mutations of the RAG genes account for a spectrum of combined immune deficiencies in humans.
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Affiliation(s)
- L D Notarangelo
- Institute of Molecular Medicine Angelo Nocivelli, Department of Pediatrics, University of Brescia, Italy.
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33
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Wang QF, Lauring J, Schlissel MS. c-Myb binds to a sequence in the proximal region of the RAG-2 promoter and is essential for promoter activity in T-lineage cells. Mol Cell Biol 2000; 20:9203-11. [PMID: 11094072 PMCID: PMC102178 DOI: 10.1128/mcb.20.24.9203-9211.2000] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The RAG-2 gene encodes a component of the V(D)J recombinase which is essential for the assembly of antigen receptor genes in B and T lymphocytes. Previously, we reported that the transcription factor BSAP (PAX-5) regulates the murine RAG-2 promoter in B-cell lines. A partially overlapping but distinct region of the proximal RAG-2 promoter was also identified as an important element for promoter activity in T cells; however, the responsible factor was unknown. In this report, we present data demonstrating that c-Myb binds to a Myb consensus site within the proximal promoter and is critical for its activity in T-lineage cells. We show that c-Myb can transactivate a RAG-2 promoter-reporter construct in cotransfection assays and that this transactivation depends on the proximal promoter Myb consensus site. By using a chromatin immunoprecipitation (ChIP) strategy, fractionation of chromatin with anti-c-Myb antibody specifically enriched endogenous RAG-2 promoter DNA sequences. DNase I genomic footprinting revealed that the c-Myb site is occupied in a tissue-specific fashion in vivo. Furthermore, an integrated RAG-2 promoter construct with mutations at the c-Myb site was not enriched in the ChIP assay, while a wild-type integrated promoter construct was enriched. Finally, this lack of binding of c-Myb to a chromosomally integrated mutant RAG-2 promoter construct in vivo was associated with a striking decrease in promoter activity. We conclude that c-Myb regulates the RAG-2 promoter in T cells by binding to this consensus c-Myb binding site.
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Affiliation(s)
- Q F Wang
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3200, USA
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34
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Hansen JD, McBlane JF. Recombination-activating genes, transposition, and the lymphoid-specific combinatorial immune system: a common evolutionary connection. Curr Top Microbiol Immunol 2000; 248:111-35. [PMID: 10793476 DOI: 10.1007/978-3-642-59674-2_6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Affiliation(s)
- J D Hansen
- Basel Institute for Immunology, Switzerland.
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35
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Abstract
Recombination activating gene-1 (RAG-1) andRAG-2 are expressed in lymphoid cells undergoing the antigen receptor gene rearrangement. A study of the regulation of the mouse RAG-2 promoter showed that the lymphocyte-specific promoter activity is conferred 80 nucleotide (nt) upstream of RAG-2. Using an electrophoretic mobility shift assay, it was shown that a B-cell–specific transcription protein, Pax-5, and a T-cell–specific transcription protein, GATA-3, bind to the −80 to −17 nt region in B cells and T cells, respectively. Mutation of the RAG-2 promoter for Pax-5– and GATA-3–binding sites results in the reduction of promoter activity in B cells and T cells. These results indicate that distinct DNA binding proteins, Pax-5 and GATA-3, may regulate the murine RAG-2 promoter in B and T lineage cells, respectively.
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36
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Abstract
Abstract
Recombination activating gene-1 (RAG-1) andRAG-2 are expressed in lymphoid cells undergoing the antigen receptor gene rearrangement. A study of the regulation of the mouse RAG-2 promoter showed that the lymphocyte-specific promoter activity is conferred 80 nucleotide (nt) upstream of RAG-2. Using an electrophoretic mobility shift assay, it was shown that a B-cell–specific transcription protein, Pax-5, and a T-cell–specific transcription protein, GATA-3, bind to the −80 to −17 nt region in B cells and T cells, respectively. Mutation of the RAG-2 promoter for Pax-5– and GATA-3–binding sites results in the reduction of promoter activity in B cells and T cells. These results indicate that distinct DNA binding proteins, Pax-5 and GATA-3, may regulate the murine RAG-2 promoter in B and T lineage cells, respectively.
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Abstract
Recombination activating genes RAG1 and RAG2 are essential components of V(D)J recombination, a process that generates the specific antigen receptors in lymphocytes. To understand the mechanisms underlying the lineage and developmental regulation of transcription of RAG2, we have characterized the human RAG2 exon 1A promoter. In this study, a series of deletion constructs were used to isolate the promoter while a linker scanning approach was taken to assess functionally relevant cis elements within the promoter. Two regulatory domains were identified. The -140 to -123 region is critical for promoter activity in all cell lines tested. Mutations to the putative Ets (-122 to -118) or to the C/EBP (-137 to -129) consensus core sequences did abrogate promoter activity, although specific DNA/protein interactions remained, as determined by EMSA. The -69 to -48 region demonstrates lineage specific promoter activity. Mutations to an overlapping, BSAP-myb-Ikaros-myb site (-65 to -39) resulted in differential promoter activity in human B and T cells. EMSA analysis of this region showed a B cell specific protein complex. Transfection of BSAP into cell lines trans-activates the human RAG2 promoter. We conclude that transcriptional regulation of the human RAG2 gene is complex, involving both tissue specific and ubiquitous factors, and both proximal and distal regulatory elements.
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Affiliation(s)
- I C Fong
- Institute of Medical Science, 610 University Avenue, Ontario Cancer Institute, Room 8-111, Ont., M5G 2M9, Toronto, Canada.
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Schwarz K, Villa A. RAG MUTATIONS IN SEVERE COMBINED IMMUNODEFICIENCY AND OMENN'S SYNDROME. Radiol Clin North Am 2000. [DOI: 10.1016/s0033-8389(22)00183-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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39
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Monroe RJ, Chen F, Ferrini R, Davidson L, Alt FW. RAG2 is regulated differentially in B and T cells by elements 5' of the promoter. Proc Natl Acad Sci U S A 1999; 96:12713-8. [PMID: 10535988 PMCID: PMC23063 DOI: 10.1073/pnas.96.22.12713] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
To study RAG2 gene regulation in vivo, we developed a blastocyst complementation method in which RAG2-deficient embryonic stem cells were transfected with genomic clones containing RAG2 and then assessed for their ability to generate lymphocytes. A RAG2 genomic clone that contained only the RAG2 promoter sequences rescued V(D)J recombination in RAG2-deficient pro-B cell lines, but did not rescue development of RAG2-deficient lymphocytes in vivo. However, inclusion of varying lengths of sequences 5' of the RAG2 promoter generated constructs capable of rescuing only in vivo B cell development, as well as other constructs that rescued both B and T cell development. In particular, the 2-kb 5' region starting just upstream of the RAG2 promoter, as well as the region from 2-7 kb 5', could independently drive B cell development, but not efficient T cell development. Deletion of the 2-kb 5' region from the murine germ line demonstrated that this region was not required for RAG expression sufficient to generate normal B or T cell numbers, implying redundancy among 5' elements. We conclude that RAG2 expression in vivo requires elements beyond the core promoter, that such elements contribute to differential regulation in the B vs. T lineages, and that sequences sufficient to direct B cell expression are located in the promoter-proximal 5' region.
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Affiliation(s)
- R J Monroe
- Howard Hughes Medical Institute, The Children's Hospital, Center for Blood Research and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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41
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Affiliation(s)
- S Desiderio
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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42
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Jessen JR, Willett CE, Lin S. Artificial chromosome transgenesis reveals long-distance negative regulation of rag1 in zebrafish. Nat Genet 1999; 23:15-6. [PMID: 10471489 DOI: 10.1038/12609] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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43
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Yu W, Misulovin Z, Suh H, Hardy RR, Jankovic M, Yannoutsos N, Nussenzweig MC. Coordinate regulation of RAG1 and RAG2 by cell type-specific DNA elements 5' of RAG2. Science 1999; 285:1080-4. [PMID: 10446057 DOI: 10.1126/science.285.5430.1080] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
RAG1 and RAG2 are essential for V(D)J recombination and lymphocyte development. These genes are thought to encode a transposase derived from a mobile genetic element that was inserted into the vertebrate genome 450 million years ago. The regulation of RAG1 and RAG2 was investigated in vivo with bacterial artificial chromosome (BAC) transgenes containing a fluorescent indicator. Coordinate expression of RAG1 and RAG2 in B and T cells was found to be regulated by distinct genetic elements found on the 5' side of the RAG2 gene. This observation suggests a mechanism by which asymmetrically disposed cis DNA elements could influence the expression of the primordial transposon and thereby capture RAGs for vertebrate evolution.
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Affiliation(s)
- W Yu
- Laboratory of Molecular Immunology, Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
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44
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Abstract
Products of the recombination-activating gene (RAG) play a crucial role in lymphoid cell development. During the past year, the functional properties of RAG protein domains have been better defined. Some mutations that alter the amino acid sequence of RAG1 or RAG2 have been shown to disturb B cell generation and to partially disturb T cell generation, resulting in Omenn syndrome in humans; moreover, peripheral re-expression of RAGs indicates their role in lymphoid cell homeostasis.
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Affiliation(s)
- L D Notarangelo
- Department of Pediatrics, University of Brescia, Spedali Civili, 25122, Brescia, Italy.
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Lauring J, Schlissel MS. Distinct factors regulate the murine RAG-2 promoter in B- and T-cell lines. Mol Cell Biol 1999; 19:2601-12. [PMID: 10082526 PMCID: PMC84053 DOI: 10.1128/mcb.19.4.2601] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The recombination activating genes RAG-1 and RAG-2 are expressed in a lymphoid-cell-specific and developmentally regulated fashion. To understand the transcriptional basis for this regulation, we have cloned and characterized the murine RAG-2 promoter. The promoter was lymphoid cell specific, showing activity in various B- and T-cell lines but little activity in nonlymphoid cells. To our surprise, however, the promoter was regulated differently in B and T cells. Using nuclear extracts from B-cell lines, we found that the B-cell-specific transcription factor BSAP (Pax-5) could bind to a conserved sequence critical for promoter activity. BSAP activated the promoter in transfected cells, and the BSAP site was occupied in a tissue-specific manner in vivo. An overlapping DNA sequence binding to a distinct factor was necessary for promoter activity in T cells. Full promoter activity in T cells was also dependent on a more distal DNA sequence whose disruption had no effect on B-cell activity. The unexpected finding that a B-cell-specific factor regulates the RAG-2 promoter may explain some of the recently observed differences in the regulation of RAG transcription between B and T cells.
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Affiliation(s)
- J Lauring
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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