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Guo CC, Xu HE, Ma X. ARID3a from the ARID family: structure, role in autoimmune diseases and drug discovery. Acta Pharmacol Sin 2023; 44:2139-2150. [PMID: 37488425 PMCID: PMC10618457 DOI: 10.1038/s41401-023-01134-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 07/09/2023] [Indexed: 07/26/2023] Open
Abstract
The AT-rich interaction domain (ARID) family of DNA-binding proteins is a group of transcription factors and chromatin regulators with a highly conserved ARID domain that recognizes specific AT-rich DNA sequences. Dysfunction of ARID family members has been implicated in various human diseases including cancers and intellectual disability. Among them, ARID3a has gained increasing attention due to its potential involvement in autoimmunity. In this article we provide an overview of the ARID family, focusing on the structure and biological functions of ARID3a. It explores the role of ARID3a in autoreactive B cells and its contribution to autoimmune diseases such as systemic lupus erythematosus and primary biliary cholangitis. Furthermore, we also discuss the potential for drug discovery targeting ARID3a and present a plan for future research in this field.
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Affiliation(s)
- Cheng-Cen Guo
- Department of Gastroenterology and Hepatology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai Institute of Digestive Disease, Shanghai, 200001, China.
| | - H Eric Xu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Xiong Ma
- Department of Gastroenterology and Hepatology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai Institute of Digestive Disease, Shanghai, 200001, China.
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Abstract
Systemic lupus erythematosus (SLE) is a devastating and heterogeneous autoimmune disease that affects multiple organs, and for which the underlying causes are unknown. The majority of SLE patients produce autoantibodies, have increased levels of type-I inflammatory cytokines, and can develop glomerulonephritis. Recent studies indicate an unexpected but strong association between increased disease activity in SLE patients and the expression of the DNA-binding protein ARID3a (A + T rich interaction domain protein 3a) in a number of peripheral blood cell types. ARID3a expression was first associated with autoantibody production in B cells; however, more recent findings also indicate associations with expression of the inflammatory cytokine interferon alpha in SLE plasmacytoid dendritic cells and low-density neutrophils. In addition, ARID3a is expressed in hematopoietic stem cells and some adult kidney progenitor cells. SLE cells expressing enhanced ARID3a levels show differential gene expression patterns compared with homologous healthy control cells, identifying new pathways potentially regulated by ARID3a. The associations of ARID3a expression with increased disease severity in SLE, suggest that it, or its downstream targets, may provide new therapeutic targets for SLE.
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Kim D, Schmidt C, Brown MA, Tucker H. Competitive Promoter-Associated Matrix Attachment Region Binding of the Arid3a and Cux1 Transcription Factors. Diseases 2017; 5:diseases5040034. [PMID: 29232859 PMCID: PMC5750545 DOI: 10.3390/diseases5040034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 12/05/2017] [Accepted: 12/05/2017] [Indexed: 01/19/2023] Open
Abstract
Arid3a/Bright/Dril1 is a B cell-specific transactivator that regulates immunoglobulin heavy chain (IgH) gene transcription by binding promoter and enhancer-associated matrix attachment regions (MARs) within the IgH gene locus. Promoter MAR-mediated Arid3a transactivation is antagonized by direct competition of MAR binding by Cux1/CDP-a ubiquitously expressed repressor originally termed NF-μNR. We report that the NF-μNR complex includes Arid3a in B cells but not in non-B cells through mobility shift assays. The binding activity of NF-μNR and Arid3a in B cells is reciprocally altered during the cell division cycle and by the B cell mitogen lipopolysaccharide LPS. LPS treatment had no effect on Arid3a localization but increased its total abundance within the nucleus and cytoplasm. We show that this increased level of Arid3a is capable of displacing Cux from the MARs to facilitate IgH gene transcription. Finally, we showed that the MARs (termed Bf150 and Tx125) associated with the VH1 rearranged variable region expressed in the S107 murine plasmacytoma, can repress reporter gene transcription in non-B cells and that they can relieve the repression mediated by Eμ enhancer in B cells. These results have significant implications for early human development and demonstrate that MARs in IgH locus, NF-µNR and Arid3a regulate IgH gene expression in a concerted fashion. This paves the way for future studies examining the misregulation of this pathway in pediatric disease.
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Affiliation(s)
- Dongkyoon Kim
- Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78715, USA.
- Atreca, Inc., Redwood City, CA 94063, USA.
| | - Christian Schmidt
- Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78715, USA.
- Department of Biomaterials and Healthcare, Division of Life Science and Bioprocesses, Fraunhofer-Institute for Applied Polymer Research (IAP), 14476 Potsdam-Golm, Germany.
| | - Mark A Brown
- Department of Clinical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
| | - Haley Tucker
- Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78715, USA.
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4
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Human effector B lymphocytes express ARID3a and secrete interferon alpha. J Autoimmun 2016; 75:130-140. [PMID: 27522115 DOI: 10.1016/j.jaut.2016.08.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 07/28/2016] [Accepted: 08/03/2016] [Indexed: 12/31/2022]
Abstract
Previously, we determined that enhanced disease activity in patients with systemic lupus erythematosus (SLE) was associated with dramatic increases in numbers of B lymphocytes expressing the transcription factor ARID3a. Our data now indicate ARID3a is important for interferon alpha (IFNa) expression and show a strong association between ARID3a expression and transcription of genes associated with lupus IFN signatures. Furthermore, both ARID3a and IFNa production were elicited in healthy control B cells upon stimulation with the TLR 9 agonist, CpG. Importantly, secretion of IFNa from ARID3a+ healthy B lymphocytes stimulated increased IFNa production in plasmacytoid dendritic cells. These data identify ARID3a+ B cells as a novel type of effector B cell, and link ARID3a expression in B lymphocytes to IFN-associated inflammatory responses in SLE.
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Ratliff ML, Mishra M, Frank MB, Guthridge JM, Webb CF. The Transcription Factor ARID3a Is Important for In Vitro Differentiation of Human Hematopoietic Progenitors. THE JOURNAL OF IMMUNOLOGY 2015; 196:614-23. [PMID: 26685208 DOI: 10.4049/jimmunol.1500355] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 11/10/2015] [Indexed: 12/12/2022]
Abstract
We recently reported that the transcription factor ARID3a is expressed in a subset of human hematopoietic progenitor stem cells in both healthy individuals and in patients with systemic lupus erythematosus. Numbers of ARID3a(+) lupus hematopoietic stem progenitor cells were associated with increased production of autoreactive Abs when those cells were introduced into humanized mouse models. Although ARID3a/Bright knockout mice died in utero, they exhibited decreased numbers of hematopoietic stem cells and erythrocytes, indicating that ARID3a is functionally important for hematopoiesis in mice. To explore the requirement for ARID3a for normal human hematopoiesis, hematopoietic stem cell progenitors from human cord blood were subjected to both inhibition and overexpression of ARID3a in vitro. Inhibition of ARID3a resulted in decreased B lineage cell production accompanied by increases in cells with myeloid lineage markers. Overexpression of ARID3a inhibited both myeloid and erythroid differentiation. Additionally, inhibition of ARID3a in hematopoietic stem cells resulted in altered expression of transcription factors associated with hematopoietic lineage decisions. These results suggest that appropriate regulation of ARID3a is critical for normal development of both myeloid and B lineage pathways.
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Affiliation(s)
| | - Meenu Mishra
- Walter Reed Army Institute of Research, Silver Spring, MD 20910
| | - Mark B Frank
- Oklahoma Medical Research Foundation, Oklahoma City, OK 73104
| | | | - Carol F Webb
- Oklahoma Medical Research Foundation, Oklahoma City, OK 73104; Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104; and Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
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Ratliff ML, Templeton TD, Ward JM, Webb CF. The Bright Side of Hematopoiesis: Regulatory Roles of ARID3a/Bright in Human and Mouse Hematopoiesis. Front Immunol 2014; 5:113. [PMID: 24678314 PMCID: PMC3958700 DOI: 10.3389/fimmu.2014.00113] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 03/04/2014] [Indexed: 12/12/2022] Open
Abstract
ARID3a/Bright is a DNA-binding protein that was originally discovered for its ability to increase immunoglobulin transcription in antigen-activated B cells. It interacts with DNA as a dimer through its ARID, or A/T-rich interacting domain. In association with other proteins, ARID3a increased transcription of the immunoglobulin heavy chain and led to improved chromatin accessibility of the heavy chain enhancer. Constitutive expression of ARID3a in B lineage cells resulted in autoantibody production, suggesting its regulation is important. Abnormal ARID3a expression has also been associated with increased proliferative capacity and malignancy. Roles for ARID3a in addition to interactions with the immunoglobulin locus were suggested by transgenic and knockout mouse models. Over-expression of ARID3a resulted in skewing of mature B cell subsets and altered gene expression patterns of follicular B cells, whereas loss of function resulted in loss of B1 lineage B cells and defects in hematopoiesis. More recent studies showed that loss of ARID3a in adult somatic cells promoted developmental plasticity, alterations in gene expression patterns, and lineage fate decisions. Together, these data suggest new regulatory roles for ARID3a. The genes influenced by ARID3a are likely to play pivotal roles in lineage decisions, highlighting the importance of this understudied transcription factor.
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Affiliation(s)
- Michelle L Ratliff
- Immunobiology and Cancer Research, Oklahoma Medical Research Foundation , Oklahoma City, OK , USA
| | - Troy D Templeton
- Department of Cell Biology, University of Oklahoma Health Sciences Center , Oklahoma City, OK , USA
| | - Julie M Ward
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center , Oklahoma City, OK , USA
| | - Carol F Webb
- Immunobiology and Cancer Research, Oklahoma Medical Research Foundation , Oklahoma City, OK , USA ; Department of Cell Biology, University of Oklahoma Health Sciences Center , Oklahoma City, OK , USA ; Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center , Oklahoma City, OK , USA
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Prieur A, Nacerddine K, van Lohuizen M, Peeper DS. SUMOylation of DRIL1 directs its transcriptional activity towards leukocyte lineage-specific genes. PLoS One 2009; 4:e5542. [PMID: 19436740 PMCID: PMC2677661 DOI: 10.1371/journal.pone.0005542] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2009] [Accepted: 04/18/2009] [Indexed: 11/18/2022] Open
Abstract
DRIL1 is an ARID family transcription factor that can immortalize primary mouse fibroblasts, bypass RASV12-induced cellular senescence and collaborate with RASV12 or MYC in mediating oncogenic transformation. It also activates immunoglobulin heavy chain transcription and engages in heterodimer formation with E2F to stimulate E2F-dependent transcription. Little, however, is known about the regulation of DRIL1 activity. Recently, DRIL1 was found to interact with the SUMO-conjugating enzyme Ubc9, but the functional relevance of this association has not been assessed. Here, we show that DRIL1 is sumoylated both in vitro and in vivo at lysine 398. Moreover, we provide evidence that PIASy functions as a specific SUMO E3-ligase for DRIL1 and promotes its sumoylation both in vitro and in vivo. Furthermore, consistent with the subnuclear localization of PIASy in the Matrix-Associated Region (MAR), SUMO-modified DRIL1 species are found exclusively in the MAR fraction. This post-translational modification interferes neither with the subcellular localization nor the DNA-binding activity of the protein. In contrast, DRIL1 sumoylation impairs its interaction with E2F1 in vitro and modifies its transcriptional activity in vivo, driving transcription of subset of genes regulating leukocyte fate. Taken together, these results identify sumoylation as a novel post-translational modification of DRIL1 that represents an important mechanism for targeting and modulating DRIL1 transcriptional activity.
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Affiliation(s)
- Alexandre Prieur
- Department of Molecular Genetics, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Karim Nacerddine
- Department of Molecular Genetics, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Maarten van Lohuizen
- Department of Molecular Genetics, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Daniel S. Peeper
- Department of Molecular Genetics, The Netherlands Cancer Institute, Amsterdam, The Netherlands
- * E-mail:
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Signalling of the BCR is regulated by a lipid rafts-localised transcription factor, Bright. EMBO J 2009; 28:711-24. [PMID: 19214191 DOI: 10.1038/emboj.2009.20] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Accepted: 01/09/2009] [Indexed: 02/06/2023] Open
Abstract
Regulation of BCR signalling strength is crucial for B-cell development and function. Bright is a B-cell-restricted factor that complexes with Bruton's tyrosine kinase (Btk) and its substrate, transcription initiation factor-I (TFII-I), to activate immunoglobulin heavy chain gene transcription in the nucleus. Here we show that a palmitoylated pool of Bright is diverted to lipid rafts of resting B cells where it associates with signalosome components. After BCR ligation, Bright transiently interacts with sumoylation enzymes, blocks calcium flux and phosphorylation of Btk and TFII-I and is then discharged from lipid rafts as a Sumo-I-modified form. The resulting lipid raft concentration of Bright contributes to the signalling threshold of B cells, as their sensitivity to BCR stimulation decreases as the levels of Bright increase. Bright regulates signalling independent of its role in IgH transcription, as shown by specific dominant-negative titration of rafts-specific forms. This study identifies a BCR tuning mechanism in lipid rafts that is regulated by differential post-translational modification of a transcription factor with implications for B-cell tolerance and autoimmunity.
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Lee J, Klase Z, Gao X, Caldwell JS, Stinski MF, Kashanchi F, Chao SH. Cellular homeoproteins, SATB1 and CDP, bind to the unique region between the human cytomegalovirus UL127 and major immediate-early genes. Virology 2007; 366:117-25. [PMID: 17512569 DOI: 10.1016/j.virol.2007.04.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Revised: 03/19/2007] [Accepted: 04/20/2007] [Indexed: 01/19/2023]
Abstract
An AT-rich region of the human cytomegalovirus (CMV) genome between the UL127 open reading frame and the major immediate-early (MIE) enhancer is referred to as the unique region (UR). It has been shown that the UR represses activation of transcription from the UL127 promoter and functions as a boundary between the divergent UL127 and MIE genes during human CMV infection [Angulo, A., Kerry, D., Huang, H., Borst, E.M., Razinsky, A., Wu, J., Hobom, U., Messerle, M., Ghazal, P., 2000. Identification of a boundary domain adjacent to the potent human cytomegalovirus enhancer that represses transcription of the divergent UL127 promoter. J. Virol. 74 (6), 2826-2839; Lundquist, C.A., Meier, J.L., Stinski, M.F., 1999. A strong negative transcriptional regulatory region between the human cytomegalovirus UL127 gene and the major immediate-early enhancer. J. Virol. 73 (11), 9039-9052]. A putative forkhead box-like (FOX-like) site, AAATCAATATT, was identified in the UR and found to play a key role in repression of the UL127 promoter in recombinant virus-infected cells [Lashmit, P.E., Lundquist, C.A., Meier, J.L., Stinski, M.F., 2004. Cellular repressor inhibits human cytomegalovirus transcription from the UL127 promoter. J. Virol. 78 (10), 5113-5123]. However, the cellular factors which associate with the UR and FOX-like region remain to be determined. We reported previously that pancreatic-duodenal homeobox factor-1 (PDX1) bound to a 45-bp element located within the UR [Chao, S.H., Harada, J.N., Hyndman, F., Gao, X., Nelson, C.G., Chanda, S.K., Caldwell, J.S., 2004. PDX1, a Cellular Homeoprotein, Binds to and Regulates the Activity of Human Cytomegalovirus Immediate Early Promoter. J. Biol. Chem. 279 (16), 16111-16120]. Here we demonstrate that two additional cellular homeoproteins, special AT-rich sequence binding protein 1 (SATB1) and CCAAT displacement protein (CDP), bind to the human CMV UR in vitro and in vivo. Furthermore, CDP is identified as a FOX-like binding protein and a repressor of the UL127 promoter, while SATB1 has no effect on UL127 expression. Since CDP is known as a transcription repressor and a nuclear matrix-associated region binding protein, CDP may have a role in the regulation of human CMV transcription.
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Affiliation(s)
- Jialing Lee
- Expression Engineering Group, Bioprocessing Technology Institute, 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
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Shankar M, Nixon JC, Maier S, Workman J, Farris AD, Webb CF. Anti-nuclear antibody production and autoimmunity in transgenic mice that overexpress the transcription factor Bright. THE JOURNAL OF IMMUNOLOGY 2007; 178:2996-3006. [PMID: 17312145 PMCID: PMC2705967 DOI: 10.4049/jimmunol.178.5.2996] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The B cell-restricted transcription factor, B cell regulator of Ig(H) transcription (Bright), up-regulates Ig H chain transcription 3- to 7-fold in activated B cells in vitro. Bright function is dependent upon both active Bruton's tyrosine kinase and its substrate, the transcription factor, TFII-I. In mouse and human B lymphocytes, Bright transcription is down-regulated in mature B cells, and its expression is tightly regulated during B cell differentiation. To determine how Bright expression affects B cell development, transgenic mice were generated that express Bright constitutively in all B lineage cells. These mice exhibited increases in total B220(+) B lymphocyte lineage cells in the bone marrow, but the relative percentages of the individual subpopulations were not altered. Splenic immature transitional B cells were significantly expanded both in total cell numbers and as increased percentages of cells relative to other B cell subpopulations. Serum Ig levels, particularly IgG isotypes, were increased slightly in the Bright-transgenic mice compared with littermate controls. However, immunization studies suggest that responses to all foreign Ags were not increased globally. Moreover, 4-wk-old Bright-transgenic mice produced anti-nuclear Abs. Older animals developed Ab deposits in the kidney glomeruli, but did not succumb to further autoimmune sequelae. These data indicate that enhanced Bright expression results in failure to maintain B cell tolerance and suggest a previously unappreciated role for Bright regulation in immature B cells. Bright is the first B cell-restricted transcription factor demonstrated to induce autoimmunity. Therefore, the Bright transgenics provide a novel model system for future analyses of B cell autoreactivity.
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Affiliation(s)
- Malini Shankar
- Immunobiology and Cancer, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Jamee C. Nixon
- Immunobiology and Cancer, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Shannon Maier
- Arthritis and Immunology Programs, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Jennifer Workman
- Arthritis and Immunology Programs, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - A. Darise Farris
- Arthritis and Immunology Programs, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Oklahoma Medical Research Foundation, Department of Microbiology and Immunobiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Carol F. Webb
- Immunobiology and Cancer, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Oklahoma Medical Research Foundation, Department of Microbiology and Immunobiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Cell Biology Department, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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Kim D, Probst L, Das C, Tucker PW. REKLES is an ARID3-restricted multifunctional domain. J Biol Chem 2007; 282:15768-77. [PMID: 17400556 DOI: 10.1074/jbc.m700397200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Bright/Dril1/ARID3a is a B cell-specific, matrix association (or attachment) region-binding transcriptional regulator of immunoglobulin heavy chain genes and of E2F1-dependent cell cycle progression. Bright contains a central DNA binding domain termed ARID (AT-rich interacting domain) and a C-terminal region termed REKLES (for a conserved amino acid motif). The ARID domain has been identified in seven highly conserved families of metazoan proteins (ARID1-5 and JARID1-2), whereas REKLES is found only in the ARID3 subfamily (composed of Bright/ARID3a, Bdp/ARID3b, and Bright-like/ARID3c). REKLES consists of two subdomains: a modestly conserved N-terminal REKLESalpha and a highly conserved (among ARID3 orthologous proteins) C-terminal REKLESbeta. Previously we showed that Bright undergoes nucleocytoplasmic shuttling and that REKLESalpha and -beta were required, respectively, for nuclear import and Crm1-dependent nuclear export. Here we show that Bright further requires REKLESbeta for self-association or paralogue association and for nuclear matrix targeting. REK-LES promotes and regulates the extent of Bright multimerization, which occurs in the absence or presence of target DNA and is necessary for specific DNA binding. REKLESbeta-mediated interaction of Bright with Bdp, which localizes strictly to the nucleus, traps Bright within the nucleus via neutralization of its nuclear export activity. These results identify REKLES as a multifunctional domain that has co-evolved with and regulates functional properties of the ARID3 DNA binding domain.
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Affiliation(s)
- Dongkyoon Kim
- Section of Molecular Genetics and Microbiology and Institute of Cell and Molecular Biology, University of Texas, Austin, Texas 78712-0162, USA
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Lin D, Ippolito GC, Zong RT, Bryant J, Koslovsky J, Tucker P. Bright/ARID3A contributes to chromatin accessibility of the immunoglobulin heavy chain enhancer. Mol Cancer 2007; 6:23. [PMID: 17386101 PMCID: PMC1852116 DOI: 10.1186/1476-4598-6-23] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Accepted: 03/26/2007] [Indexed: 01/27/2023] Open
Abstract
Bright/ARID3A is a nuclear matrix-associated transcription factor that stimulates immunoglobulin heavy chain (IgH) expression and Cyclin E1/E2F-dependent cell cycle progression. Bright positively activates IgH transcriptional initiation by binding to ATC-rich P sites within nuclear matrix attachment regions (MARs) flanking the IgH intronic enhancer (Eμ). Over-expression of Bright in cultured B cells was shown to correlate with DNase hypersensitivity of Eμ. We report here further efforts to analyze Bright-mediated Eμ enhancer activation within the physiological constraints of chromatin. A system was established in which VH promoter-driven in vitro transcription on chromatin- reconstituted templates was responsive to Eμ. Bright assisted in blocking the general repression caused by nucleosome assembly but was incapable of stimulating transcription from prebound nucleosome arrays. In vitro transcriptional derepression by Bright was enhanced on templates in which Eμ is flanked by MARs and was inhibited by competition with high affinity Bright binding (P2) sites. DNase hypersensitivity of chromatin-reconstituted Eμ was increased when prepackaged with B cell nuclear extract supplemented with Bright. These results identify Bright as a contributor to accessibility of the IgH enhancer.
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Affiliation(s)
- Danjuan Lin
- Section of Molecular Genetics and Microbiology and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, Texas, USA
| | - Gregory C Ippolito
- Section of Molecular Genetics and Microbiology and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, Texas, USA
| | - Rui-Ting Zong
- Section of Molecular Genetics and Microbiology and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, Texas, USA
| | - James Bryant
- Section of Molecular Genetics and Microbiology and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, Texas, USA
| | - Janet Koslovsky
- Section of Molecular Genetics and Microbiology and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, Texas, USA
| | - Philip Tucker
- Section of Molecular Genetics and Microbiology and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, Texas, USA
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Abstract
BACKGROUND S/MARs are regions of the DNA that are attached to the nuclear matrix. These regions are known to affect substantially the expression of genes. The computer prediction of S/MARs is a highly significant task which could contribute to our understanding of chromatin organisation in eukaryotic cells, the number and distribution of boundary elements, and the understanding of gene regulation in eukaryotic cells. However, while a number of S/MAR predictors have been proposed, their accuracy has so far not come under scrutiny. RESULTS We have selected S/MARs with sufficient experimental evidence and used these to evaluate existing methods of S/MAR prediction. Our main results are: 1.) all existing methods have little predictive power, 2.) a simple rule based on AT-percentage is generally competitive with other methods, 3.) in practice, the different methods will usually identify different sub-sequences as S/MARs, 4.) more research on the H-Rule would be valuable. CONCLUSION A new insight is needed to design a method which will predict S/MARs well. Our data, including the control data, has been deposited as additional material and this may help later researchers test new predictors.
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Moreira PN, Pérez-Crespo M, Ramírez MA, Pozueta J, Montoliu L, Gutiérrez-Adán A. Effect of transgene concentration, flanking matrix attachment regions, and RecA-coating on the efficiency of mouse transgenesis mediated by intracytoplasmic sperm injection. Biol Reprod 2006; 76:336-43. [PMID: 17035637 DOI: 10.1095/biolreprod.106.056952] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Intracytoplasmic sperm injection (ICSI) of DNA-loaded sperm cells has been shown to be a valuable tool for the production of transgenic animals, especially when DNA constructs with submegabase magnitude are used. In order to optimize and to understand the mechanism of the ICSI-mediated transgenesis, we have evaluated the impact of transgene DNA concentration, transgene flanking with nuclear matrix attachment regions (MARs), and the use of recombinase A (RecA)-coated DNA on the efficiency of mouse transgenesis production by ICSI. Presented data include assays with three DNA constructs; an enhanced green fluorescent protein (EGFP) plasmid of 5.4 kb, this plasmid flanked with two MAR elements (2.3 Kb of the human beta-interferon domain boundaries), and a yeast artificial chromosome (YAC) construct of approximately 510 kb (the largest transgenic construct introduced by ICSI that we have seen reported). ICSI-mediated transgenesis was done in the B6D2 mouse strain using different concentrations for each construct. Analysis of generated data indicated that ICSI allows the use of higher DNA concentrations than the ones used for pronuclear microinjection, however, when a certain threshold is exceeded, embryo/fetal viability decrease dramatically. In addition, independently of the transgene concentration tested, transgene flanking with MAR sequences did not have a significant impact on the efficiency of this transgenesis method. Finally, we observed that although the overall efficiency of ICSI-mediated transgenesis with fresh spermatozoa and RecA-complexed DNA was similar to the one obtained with the common ICSI-mediated transgenesis approach with frozen-thawed spermatozoa and RecA free DNA, this method was not as efficient in maintaining a low frequency of founder animal mosaicism, suggesting that different mechanisms of transgene integration might result from each procedure.
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Affiliation(s)
- Pedro Nuno Moreira
- Departamento de Reproducción Animal y Conservación de Recursos Zoogenéticos, Instituto National de Investigación y Technología Agranria, 28040 Madrid, Spain
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Johnston CM, Wood AL, Bolland DJ, Corcoran AE. Complete Sequence Assembly and Characterization of the C57BL/6 Mouse Ig Heavy Chain V Region. THE JOURNAL OF IMMUNOLOGY 2006; 176:4221-34. [PMID: 16547259 DOI: 10.4049/jimmunol.176.7.4221] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The mechanisms that regulate variable (V) gene selection during the development of the mouse IgH repertoire are not fully understood, due in part to the absence of the complete locus sequence. To better understand these processes, we have assembled the entire 2.5-Mb mouse IgH (Igh) V region sequence of the C57BL/6 strain from public sequences and present the first complete annotated map of the region, including V genes, pseudogenes, repeats, and nonrepetitive intergenic sequences. In so doing, we have discovered a new V gene family, VH16. We have identified clusters of conserved region-specific intergenic sequences and have verified our assembly by genic and intergenic Southern blotting. We have observed that V pseudogenes are not evenly spread throughout the V region, but rather cluster together. The largest J558 family, which spans more than half of the locus, has two strikingly different domains, which suggest points of evolutionary divergence or duplication. The 5' end contains widely spaced J558 genes interspersed with 3609 genes and is pseudogene poor. The 3' end contains closely spaced J558 genes, no 3609 genes, and is pseudogene rich. Each occupies a different branch of the phylogenetic tree. Detailed analysis of 500-bp upstream of all functional genes has revealed several conserved binding sites, general and B cell-specific, as well as key differences between families. This complete and definitive assembly of the mouse Igh V region will facilitate detailed study of promoter function and large-scale mechanisms associated with V(D)J recombination including locus contraction and antisense intergenic transcription.
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Affiliation(s)
- Colette M Johnston
- Laboratory of Chromatin and Gene Expression, Babraham Institute, Cambridge, UK
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16
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Nixon JC, Rajaiya J, Webb CF. Mutations in the DNA-binding domain of the transcription factor Bright act as dominant negative proteins and interfere with immunoglobulin transactivation. J Biol Chem 2004; 279:52465-72. [PMID: 15456761 DOI: 10.1074/jbc.m403028200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Bright, for B cell regulator of immunoglobulin heavy chain transcription, binds A+T-rich sequences in the intronic enhancer regions of the murine heavy chain locus and 5'-flanking sequences of some variable heavy chain promoters. Most resting B cells do not express Bright; however, it is induced after stimulation with antigen or polyclonal mitogens. Bright activation results in up-regulation of mu transcription; however, it is not clear whether Bright function is critical for normal B cell development. To begin to address Bright function during B cell development, seven mutated forms of Bright were produced. Five of the seven mutants revealed little or no DNA binding activity. Furthermore, because Bright binds DNA as a dimer, two of the mutants formed complexes with wild type Bright and acted in a dominant negative fashion. Dominant negative Bright prevented the up-regulation of mu transcription in transfected Chinese hamster ovary cells transfected with wild type Bright. These data identify regions within Bright that are required for the DNA binding activity of Bright and for its function as a transcription factor.
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Affiliation(s)
- Jamee C Nixon
- Oklahoma Medical Research Foundation, 825 N. E. 13 Street, Oklahoma City, Oklahoma 73104, USA
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17
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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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18
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Nixon JC, Rajaiya JB, Ayers N, Evetts S, Webb CF. The transcription factor, Bright, is not expressed in all human B lymphocyte subpopulations. Cell Immunol 2004; 228:42-53. [PMID: 15203319 DOI: 10.1016/j.cellimm.2004.03.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2003] [Accepted: 03/21/2004] [Indexed: 01/23/2023]
Abstract
Bright is an ARID family transcription factor that increases immunoglobulin heavy chain transcription. In the mouse, Bright expression is tightly regulated and B cell-restricted and the Bright protein associates with Bruton's tyrosine kinase (Btk), the defective enzyme in X-linked immunodeficiency. Human X-linked agammaglobulinemia results from defects in Btk and leads to early blocks in B lymphocyte development. Because so little is known about human Bright, we sought to determine where human Bright is expressed in normal B cell differentiation and whether it also forms complexes with Btk. Although human and mouse Bright exhibited similar expression patterns in normal B cells, many human transformed B cell lines did not express Bright protein. However, the human protein bound prototypic Bright DNA-binding motifs and, like mouse Bright, was capable of associating with Btk. These data suggest potentially important similarities exist in Bright expression and activity in human and mouse B lymphocytes.
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Affiliation(s)
- Jamee C Nixon
- Department of Microbiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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19
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Kaul R, Mukherjee S, Ahmed F, Bhat MK, Chhipa R, Galande S, Chattopadhyay S. Direct interaction with and activation of p53 by SMAR1 retards cell-cycle progression at G2/M phase and delays tumor growth in mice. Int J Cancer 2003; 103:606-15. [PMID: 12494467 DOI: 10.1002/ijc.10881] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The tumor-suppressor p53 is a multifunctional protein mainly responsible for maintaining genomic integrity. p53 induces its tumor-suppressor activity by either causing cell-cycle arrest (G(1)/S or G(2)/M) or inducing cells to undergo apoptosis. This function of wild-type p53 as "guardian of the genome" is presumably achieved by forming molecular complexes with different DNA targets as well as by interacting with a number of cellular proteins, e.g., Mdm2, Gadd45, p21, 14-3-3sigma, Bax and Apaf-1. Upon activation, p53 activates p21, which in turn controls the cell cycle by regulating G(1) or G(2) checkpoints. Here, we report SMAR1 as one such p53-interacting protein that is involved in delaying tumor progression in vivo as well as in regulating the cell cycle. SMAR1 is a newly identified MARBP involved in chromatin-mediated gene regulation. The SMAR1 gene encodes at least 2 alternatively spliced variants: SMAR1(L) (the full-length form) and SMAR1(S) (the shorter form). We report that expression of SMAR1(S), but not of SMAR1(L), mRNA was decreased in most of the human cell lines examined, suggesting selective silencing of SMAR1(S). Overexpression of SMAR1(S) in mouse melanoma cells (B16F1) and their subsequent injection in C57BL/6 mice delays tumor growth. Exogenous SMAR1(S) causes significant retardation of B16F1 cells in the G(2)/M phase of the cell cycle compared to SMAR1(L). SMAR1(S) activates p53-mediated reporter gene expression in mouse melanoma cells, breast cancer cells (MCF-7) and p53 null cells (K562), followed by activation of its downstream effector, p21. We further demonstrate that SMAR1 physically interacts and colocalizes with p53. These data together suggest that SMAR1 is the only known MARBP that delays tumor progression via direct activation and interaction with tumor-suppressor p53.
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Affiliation(s)
- Ruchika Kaul
- National Center for Cell Science, Pune University Campus, Pune, India
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20
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Goebel P, Montalbano A, Ayers N, Kompfner E, Dickinson L, Webb CF, Feeney AJ. High frequency of matrix attachment regions and cut-like protein x/CCAAT-displacement protein and B cell regulator of IgH transcription binding sites flanking Ig V region genes. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:2477-87. [PMID: 12193717 DOI: 10.4049/jimmunol.169.5.2477] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A major component in controlling V(D)J recombination is differential accessibility through localized changes in chromatin structure. Attachment of DNA to the nuclear matrix via matrix attachment region (MAR) sequences, and interaction with MAR-binding proteins have been shown to alter chromatin conformation, promote histone acetylation, and influence gene transcription. In this study, the flanking regions of several human and mouse Ig V(H) and Ig Vkappa genes were analyzed extensively for the presence of MARs by in vitro matrix-binding assay, and for interaction with the MAR-binding proteins cut-like protein x/CCAAT-displacement protein (Cux/CDP), B cell regulator of IgH transcription (Bright), and special AT-rich sequence-binding protein (SATB1) by EMSA. Cux/CDP and SATB1 are associated with repression, while Bright is an activator of Ig transcription. Binding sites were identified in the vicinity of all analyzed Ig V genes, and were also found flanking TCR Vbeta genes. We also show that the binding sites of the different factors do not always occur at MAR sequences. MAR sequences were also found within the Ig V loci at a much higher frequency than throughout the rest of the genome. Overall, the frequency and location of binding sites relative to the coding regions, and the strength of DNA-protein interaction showed much heterogeneity. Thus, variations in factor binding and MAR activity could potentially influence the extent of localized accessibility to V(D)J recombination and thus could play a role in unequal rearrangement of individual V genes. These sites could also contribute to effective transcription of Ig genes in mature and/or activated B cells, bringing both the promoter as well as the enhancer regions into close proximity at the nuclear matrix.
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Affiliation(s)
- Peter Goebel
- The Scripps Research Institute, La Jolla, CA 92037, USA
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21
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Kieffer LJ, Greally JM, Landres I, Nag S, Nakajima Y, Kohwi-Shigematsu T, Kavathas PB. Identification of a candidate regulatory region in the human CD8 gene complex by colocalization of DNase I hypersensitive sites and matrix attachment regions which bind SATB1 and GATA-3. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:3915-22. [PMID: 11937547 DOI: 10.4049/jimmunol.168.8.3915] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To locate elements regulating the human CD8 gene complex, we mapped nuclear matrix attachment regions (MARs) and DNase I hypersensitive (HS) sites over a 100-kb region that included the CD8B gene, the intergenic region, and the CD8A gene. MARs facilitate long-range chromatin remodeling required for enhancer activity and have been found closely linked to several lymphoid enhancers. Within the human CD8 gene complex, we identified six DNase HS clusters, four strong MARs, and several weaker MARs. Three of the strong MARs were closely linked to two tissue-specific DNase HS clusters (III and IV) at the 3' end of the CD8B gene. To further establish the importance of this region, we obtained 19 kb of sequence and screened for potential binding sites for the MAR-binding protein, SATB1, and for GATA-3, both of which are critical for T cell development. By gel shift analysis we identified two strong SATB1 binding sites, located 4.5 kb apart, in strong MARs. We also detected strong GATA-3 binding to an oligonucleotide containing two GATA-3 motifs located at an HS site in cluster IV. This clustering of DNase HS sites and MARs capable of binding SATB1 and GATA-3 at the 3' end of the CD8B gene suggests that this region is an epigenetic regulator of CD8 expression.
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Affiliation(s)
- Lynda J Kieffer
- Department of Laboratory Medicine and Department of Genetics and Section of Immunobiology, Yale University, New Haven, CT 06520, USA
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22
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Kaplan MH, Zong RT, Herrscher RF, Scheuermann RH, Tucker PW. Transcriptional activation by a matrix associating region-binding protein. contextual requirements for the function of bright. J Biol Chem 2001; 276:21325-30. [PMID: 11294836 DOI: 10.1074/jbc.m100836200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Bright (B cell regulator of IgH transcription) is a B cell-specific, matrix associating region-binding protein that transactivates gene expression from the IgH intronic enhancer (E mu). We show here that Bright has multiple contextual requirements to function as a transcriptional activator. Bright cannot transactivate via out of context, concatenated binding sites. Transactivation is maximal on integrated substrates. Two of the three previously identified binding sites in E mu are required for full Bright transactivation. The Bright DNA binding domain defined a new family, which includes SWI1, a component of the SWI.SNF complex shown to have high mobility group-like DNA binding characteristics. Similar to one group of high mobility group box proteins, Bright distorts E mu binding site-containing DNA on binding, supporting the concept that it mediates E mu remodeling. Transfection studies further implicate Bright in facilitating spatially separated promoter-enhancer interactions in both transient and stable assays. Finally, we show that overexpression of Bright leads to enhanced DNase I sensitivity of the endogenous E mu matrix associating regions. These data further suggest that Bright may contribute to increased gene expression by remodeling the immunoglobulin locus during B cell development.
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Affiliation(s)
- M H Kaplan
- Institute for Molecular and Cellular Biology, University of Texas at Austin, Austin, Texas 78712-1075, USA
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23
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Abstract
Members of the recently discovered ARID (AT-rich interaction domain) family of DNA-binding proteins are found in fungi and invertebrate and vertebrate metazoans. ARID-encoding genes are involved in a variety of biological processes including embryonic development, cell lineage gene regulation and cell cycle control. Although the specific roles of this domain and of ARID-containing proteins in transcriptional regulation are yet to be elucidated, they include both positive and negative transcriptional regulation and a likely involvement in the modification of chromatin structure.
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Affiliation(s)
- R D Kortschak
- Centre for Molecular Genetics of Development and Dept of Genetics, University of Adelaide, Adelaide, SA 5005, Australia
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24
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Malone CS, Patrone L, Buchanan KL, Webb CF, Wall R. An upstream Oct-1- and Oct-2-binding silencer governs B29 (Ig beta) gene expression. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:2550-6. [PMID: 10679093 DOI: 10.4049/jimmunol.164.5.2550] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The B cell-specific B29 (Igbeta) gene is activated in the earliest B cell precursors and is expressed throughout B cell development. Tissue-specific expression of the murine B29 gene is controlled by a B cell-specific promoter whose activity is governed by a cassette of upstream transcriptional silencers. This study describes a potent new silencer that is located 5' of the previously identified B29 silencer elements, FROG and TOAD. Like these known elements, the new B29 silencer is not restricted to the B29 promoter. Nuclear proteins from all cell lines tested interacted with this A+T-rich sequence, which closely resembled a noncanonical octamer binding motif and also conformed to the consensus sequence for nuclear matrix attachment regions. Interaction of Oct-1 and Oct-2 with the B29 A+T-rich sequence was confirmed using octamer-specific Abs. Oct-1/Oct-2 binding was required for the inhibitory activity of this sequence because mutations that blocked Oct-1/Oct-2 binding also eliminated inhibition of the B29 promoter. This B29 A+T-rich sequence specifically interacted with isolated nuclear matrix proteins in vitro, suggesting that it may also function as a matrix attachment region element. Maintenance of the level of B29 gene expression through the interaction of the minimal promoter and the upstream silencer elements FROG, TOAD, and the A+T-rich Oct-1/Oct-2 binding motif may be essential for normal B cell development and/or function.
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Affiliation(s)
- C S Malone
- Department of Microbiology and Immunology, and Molecular Biology Institute, University of California, School of Medicine, Los Angeles, CA 90095, USA
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25
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Sakai E, Bottaro A, Alt FW. The Ig heavy chain intronic enhancer core region is necessary and sufficient to promote efficient class switch recombination. Int Immunol 1999; 11:1709-13. [PMID: 10508189 DOI: 10.1093/intimm/11.10.1709] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The intronic IgH enhancer E(mu), which consists of the core enhancer (cE(mu) flanked by 5' and 3' matrix attachment regions (MAR), has been implicated in the control of IgH locus recombination and transcription. Both cE(mu) and the MAR are required to enhance transcription of an IgH transgene. To elucidate the regulatory functions of cE(mu) versus its associated MAR in IgH class switch recombination (CSR), we have assayed ES cell lines which have targeted deletions of these elements, both individually and in combination, by the Rag-2-deficient blastocyst complementation method. Mutant B cells from chimeric mice were activated in culture and the influence of the mutations on CSR was assessed by analysis of B cell hybridomas. We find that the cE(mu) is necessary and sufficient for providing the functions of E(mu) required for efficient CSR at the IgH locus. However, the 5' and 3' MAR sequences, as well as the known I(mu) transcription start sites and the bulk of I(mu) coding sequences, were dispensable for the process.
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Affiliation(s)
- E Sakai
- Howard Hughes Medical Institute, The Children's Hospital, and The Center for Blood Research and Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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26
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Wiersma EJ, Ronai D, Berru M, Tsui FW, Shulman MJ. Role of the intronic elements in the endogenous immunoglobulin heavy chain locus. Either the matrix attachment regions or the core enhancer is sufficient to maintain expression. J Biol Chem 1999; 274:4858-62. [PMID: 9988726 DOI: 10.1074/jbc.274.8.4858] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
High level expression in mice of transgenes derived from the immunoglobulin heavy chain (IgH) locus requires both the core enhancer (Emu) and the matrix attachment regions (MARs) that flank Emu. The need for both elements implies that they each perform a different function in transcription. While it is generally assumed that expression of the endogenous IgH locus has similar requirements, it has been difficult to assess the role of these elements in expression of the endogenous heavy chain gene, because B cell development and IgH expression are strongly interdependent and also because the locus contains other redundant activating elements. We have previously described a gene-targeting approach in hybridoma cells that overcomes the redundancy problem to yield a stable cell line in which expression of the IgH locus depends strongly on elements in the MAR-Emu-MAR segment. Using this system, we have found that expression of the endogenous mu gene persists at substantially (approximately 50%) normal levels in recombinants which retain either the MARs or Emu. That is, despite the dissimilar biochemical activities of these two elements, either one is sufficient to maintain high level expression of the endogenous locus. These findings suggest new models for how the enhancer and MARs might collaborate in the initiation or maintenance of transcription.
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Affiliation(s)
- E J Wiersma
- Department of Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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27
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Chattopadhyay S, Whitehurst CE, Chen J. A nuclear matrix attachment region upstream of the T cell receptor beta gene enhancer binds Cux/CDP and SATB1 and modulates enhancer-dependent reporter gene expression but not endogenous gene expression. J Biol Chem 1998; 273:29838-46. [PMID: 9792700 DOI: 10.1074/jbc.273.45.29838] [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: 01/19/2023] Open
Abstract
We have previously identified a DNase I-hypersensitive site in the T cell receptor beta locus, designated HS1, that is located 400 base pairs upstream of the transcriptional enhancer Ebeta and is induced during CD4(-)CD8(-) to CD4(+)CD8(+) thymocyte differentiation. Using electrophoretic mobility shift assays, we show that HS1 induction correlates with increased binding of two nuclear factors, Cux/CDP and SATB1, to a 170-base pair DNA sequence within HS1. Furthermore, we demonstrate that HS1 is a nuclear matrix attachment region, referred to as MARbeta. These findings demonstrate that an analogous organization of cis-regulatory elements in which a nuclear matrix attachment region is in close proximity to an enhancer is conserved in the immunoglobulin and T cell receptor loci. In addition, we show that MARbeta represses Ebeta-dependent reporter gene expression in transient transfection assays. However, the targeted deletion of MARbeta from the endogenous locus does not change T cell receptor beta gene transcription in developing T cells. These contrasting results suggest a potential pitfall of functional studies of nuclear matrix attachment regions outside of their natural chromosomal context.
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Affiliation(s)
- S Chattopadhyay
- Center for Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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28
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Webb CF, Smith EA, Medina KL, Buchanan KL, Smithson G, Dou S. Expression of Bright at Two Distinct Stages of B Lymphocyte Development. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.160.10.4747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
The B cell regulator of Ig heavy chain transcription (Bright) is a DNA-binding protein that was originally discovered in a mature Ag-specific B cell line after stimulation with IL-5 and Ag. It binds to the intronic heavy chain enhancer and 5′ of the V1 S107 family VH promoter. Several studies suggested that Bright may increase transcription of the heavy chain locus, and expression in cell lines was limited to those representing mature B cells. We have now analyzed normal hemopoietic tissues for the expression of Bright during B lymphocyte differentiation. We expected to find Bright expression in a subset of mature spleen cells, but also observed Bright in a subset of normal B lymphocytic progenitors in both adult bone marrow (BM) and in fetal liver as early as day 12 of gestation. Bright was also expressed in the small percentage of CD4low cells in the thymus that are newly arrived from the BM and are not yet committed to the T lymphocyte lineage, but was not observed at later stages of T cell differentiation in either the spleen or thymus. Bright mRNA was not detected in the immature B lymphocytes that initially populate the spleen after migration from the BM. In addition, new splice variants of Bright were observed in fetal tissues. Thus, Bright expression is highly regulated in normal murine lymphocytes and occurs both early and late during B cell differentiation. These findings may have important implications for the function of Bright in regulating Ig transcription.
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Affiliation(s)
- Carol F. Webb
- *Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, and
- †Department of Microbiology and Immunology, Oklahoma University Health Sciences Center, Oklahoma City, OK 73104
| | - Elizabeth A. Smith
- *Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, and
| | - Kay L. Medina
- *Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, and
| | - Kent L. Buchanan
- †Department of Microbiology and Immunology, Oklahoma University Health Sciences Center, Oklahoma City, OK 73104
| | - Glennda Smithson
- *Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, and
| | - Shenshen Dou
- *Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, and
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29
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Banan M, Rojas IC, Lee WH, King HL, Harriss JV, Kobayashi R, Webb CF, Gottlieb PD. Interaction of the nuclear matrix-associated region (MAR)-binding proteins, SATB1 and CDP/Cux, with a MAR element (L2a) in an upstream regulatory region of the mouse CD8a gene. J Biol Chem 1997; 272:18440-52. [PMID: 9218488 DOI: 10.1074/jbc.272.29.18440] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Matrix-associated regions (MARs), AT-rich DNA segments that have an affinity for the nuclear matrix, have been shown to play a role in transcriptional regulation of eukaryotic genes. The present study demonstrates that a DNA element, called L2a, which has been implicated in the transcriptional regulation of the mouse CD8a gene encoding an important T cell coreceptor, is a MAR. Moreover, the identities of two nuclear proteins, L2a-P1 and L2a-P2, previously shown to bind to the L2a element, have been determined. The L2a-P1 protein found to be present in all CD8-positive T cell lines tested is SATB1, a known MAR-binding protein. The widely expressed L2a-P2 protein is CDP/Cux, a MAR-binding protein that has been associated with repression of gene transcription. Interaction of both proteins with the L2a element was studied using the missing nucleoside approach, DNase I footprinting, and electrophoretic mobility shift assays with wild type and mutant L2a elements. The data suggest that CDP/Cux bound to the L2a element is displaced by binding of SATB1 and the accompanying conformational change in the DNA lying between the primary binding sites of SATB1 and CDP/Cux. We suggest that displacement of CDP/Cux by SATB1 favors transcription of the CD8a gene, possibly by enhancing or altering its association with the nuclear matrix.
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Affiliation(s)
- M Banan
- Department of Microbiology and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas 78712, USA
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30
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Sleckman BP, Gorman JR, Alt FW. Accessibility control of antigen-receptor variable-region gene assembly: role of cis-acting elements. Annu Rev Immunol 1996; 14:459-81. [PMID: 8717521 DOI: 10.1146/annurev.immunol.14.1.459] [Citation(s) in RCA: 238] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Antigen receptor variable region genes are assembled from germline variable (V), diversity (D), and joining (J) gene segments. This process requires expression of V(D)J recombinase activity, and "accessibility" of variable gene segments to this recombinase. The exact mechanism by which variable gene segments become accessible during development is not known. However, several studies have shown that cis-acting elements that regulate transcription may also function to regulate accessibility. Here we review the evidence that transcriptional promoters, enhancers, and silencers are involved in regulation of accessibility. The manner in which these elements may combine to regulate accessibility is addressed. In addition, current and potential strategies for identifying and analyzing cis-acting elements that mediate locus accessibility are discussed.
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Affiliation(s)
- B P Sleckman
- Howard Hughes Medical Institute, Children's Hospital, Boston, Massachusetts 02115, USA
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31
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Boulikas T. Chromatin domains and prediction of MAR sequences. INTERNATIONAL REVIEW OF CYTOLOGY 1996; 162A:279-388. [PMID: 8575883 DOI: 10.1016/s0074-7696(08)61234-6] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Polynuceosomes are constrained into loops or domains and are insulated from the effects of chromatin structure and torsional strain from flanking domains by the cross-complexation of matrix-attached regions (MARs) and matrix proteins. MARs or SARs have an average size of 500 bp, are spaced about every 30 kb, and are control elements maintaining independent realms of gene activity. A fraction of MARs may cohabit with core origin replication (ORIs) and another fraction might cohabit with transcriptional enhancers. DNA replication, transcription, repair, splicing, and recombination seem to take place on the nuclear matrix. Classical AT-rich MARs have been proposed to anchor the core enhancers and core origins complexed with low abundancy transcription factors to the nuclear matrix via the cooperative binding to MARs of abundant classical matrix proteins (topoisomerase II, histone H1, lamins, SP120, ARBP, SATB1); this creates a unique nuclear microenvironment rich in regulatory proteins able to sustain transcription, replication, repair, and recombination. Theoretical searches and experimental data strongly support a model of activation of MARs and ORIs by transcription factors. A set of 21 characteristics are deduced or proposed for MAR/ORI sequences including their enrichment in inverted repeats, AT tracts, DNA unwinding elements, replication initiator protein sites, homooligonucleotide repeats (i.e., AAA, TTT, CCC), curved DNA, DNase I-hypersensitive sites, nucleosome-free stretches, polypurine stretches, and motifs with a potential for left-handed and triplex structures. We are establishing Banks of ORI and MAR sequences and have undertaken a large project of sequencing a large number of MARs in an effort to determine classes of DNA sequences in these regulatory elements and to understand their role at the origins of replication and transcriptional enhancers.
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Affiliation(s)
- T Boulikas
- Institute of Molecular Medical Sciences, Palo Alto, California 94306, USA
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Zong RT, Scheuermann RH. Mutually exclusive interaction of a novel matrix attachment region binding protein and the NF-muNR enhancer repressor. Implications for regulation of immunoglobulin heavy chain expression. J Biol Chem 1995; 270:24010-8. [PMID: 7592598 DOI: 10.1074/jbc.270.41.24010] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The immunoglobulin heavy chain (IgH) intronic enhancer stimulates transcription from functional promoters in B lymphocytes but not other cell types. The observation that binding sites for the nuclear factor-mu negative regulator (NF-muNR) enhancer repressor overlap nuclear matrix attachment regions (MARs) in this enhancer has lead to the hypothesis that the cell type specificity of the enhancer might be controlled by regulating nuclear matrix attachment (Scheuermann, R. H., and Chen, U. (1989) Genes & Dev. 3, 1255-1266). To understand the role of MARs in IgH enhancer regulation, we have identified a novel MAR-binding protein, MAR-BP1, from soluble nuclear matrix preparations based on its ability to bind to the MARs associated with the IgH enhancer. Purified MAR-BP1 migrates as a 33-kDa protein, and it can be found in nuclear matrix preparations from a number of different types of lymphoid cell lines. Although specific binding sites have been difficult to localize by chemical or enzymatic footprinting procedures, NF-muNR binding sites are critical for efficient MAR-BP1 binding. Indeed, binding of the IgH enhancer to either intact nuclear matrix preparations or to MAR-BP1 is mutually exclusive to NF-muNR binding. These results are consistent with a model for cell-type specific regulation in which binding of the NF-muNR repressor to the IgH enhancer prevents nuclear matrix attachment in inappropriate cells by interfering with MAR-BP1/enhancer interaction.
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Affiliation(s)
- R T Zong
- Laboratory of Molecular Pathology, University of Texas Southwestern Medical Center, Dallas 75235-9072, USA
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Nakanishi-Matsui M, Kubo T, Natori S. Molecular Cloning and Nuclear Localization of ATBP, A Novel (A+T)-Stretch-binding Protein of Sarcophaga peregrina (Flesh Fly). ACTA ACUST UNITED AC 1995. [DOI: 10.1111/j.1432-1033.1995.0396h.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Breyne P, Van Montagu M, Gheysen G. The role of scaffold attachment regions in the structural and functional organization of plant chromatin. Transgenic Res 1994; 3:195-202. [PMID: 8025597 DOI: 10.1007/bf01973987] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Studies on nuclear scaffolds and scaffold attachment regions (SARs) have recently been extended to different plant species and indicate that SARs are involved in the structural and functional organization of the plant genome, as is the case for other eukaryotes. One type of SAR seems to delimit structural chromatin loops and may also border functional units of gene expression and DNA replication. Another group of SARs map close to regulatory elements and may be directly involved in gene expression. In this overview, we summarize the structural and functional properties of plant SARs in comparison with those of SARs from animals and yeast.
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Affiliation(s)
- P Breyne
- Laboratorium voor Genetica, Universiteit Gent, Belgium
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