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Zheng C, Wu H, Jin S, Li D, Tan S, Zhu X. Roles of Myc-associated zinc finger protein in malignant tumors. Asia Pac J Clin Oncol 2022; 18:506-514. [PMID: 35098656 DOI: 10.1111/ajco.13748] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 12/04/2021] [Indexed: 11/30/2022]
Abstract
As an important transcription factor that is widely expressed in most tissues of the human body, Myc-associated zinc finger protein (MAZ) has been reported highly expressed in many malignant tumors and thought to be a promising therapeutic target for cancer treatment. In this review, we aim to offer a comprehensive understanding of MAZ regulation in malignant tumors. The carboxy terminal of MAZ protein contains six C2H2 zinc fingers, and its regulation of transcription is based on the interaction between the GC-rich DNA binding sites of target genes and its carboxy-terminal zinc finger motifs. MAZ protein has been found to activate or inhibit the transcriptional initiation process of many target genes, as well as play an important role in the transcriptional termination process of some target genes, so MAZ poses dual regulatory functions in the initiation and termination process of gene transcription. Through the transcriptional regulation of c-myc and Ras gene family, MAZ poses an important role in the occurrence and development of breast cancer, pancreatic cancer, prostate cancer, glioblastoma, neuroblastoma, and other malignant tumors. Our review shows a vital role of MAZ in many malignant tumors and provides novel insight for cancer diagnosis and treatment.
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Affiliation(s)
- Chuanjun Zheng
- Department of Epidemiology and Statistics, School of Public Health, Guilin Medical University, Guilin, China
| | - Hongmei Wu
- Department of Epidemiology and Statistics, School of Public Health, Guilin Medical University, Guilin, China
| | - Song Jin
- Department of Epidemiology and Statistics, School of Public Health, Guilin Medical University, Guilin, China
| | - Di Li
- Department of Epidemiology and Statistics, School of Public Health, Guilin Medical University, Guilin, China
| | - Shengkui Tan
- Department of Epidemiology and Statistics, School of Public Health, Guilin Medical University, Guilin, China
| | - Xiaonian Zhu
- Department of Epidemiology and Statistics, School of Public Health, Guilin Medical University, Guilin, China
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Tang H, Jiang X, Zhang J, Pei C, Zhao X, Li L, Kong X. Teleost CD4 + helper T cells: Molecular characteristics and functions and comparison with mammalian counterparts. Vet Immunol Immunopathol 2021; 240:110316. [PMID: 34474261 DOI: 10.1016/j.vetimm.2021.110316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 06/21/2021] [Accepted: 08/24/2021] [Indexed: 12/24/2022]
Abstract
CD4+ helper T cells play key and diverse roles in inducing adaptive immune responses in vertebrates. The CD4 molecule, which is found on the surfaces of CD4+ helper T cells, can be used to distinguish subsets of helper T cells. Teleosts are the oldest living species with bona-fide CD4 coreceptors. Although some components of immune systems of teleosts and mammals appear to be similar, many physiological differences are represented between them. Previous studies have shown that two CD4 paralogs are present in teleosts, whereas only one is present in mammals. Therefore, in this review, the CD4 molecular structure, expression profiles, subpopulations, and biological functions of teleost CD4+ helper T cells were summarized and compared with those of their mammalian counterparts to understand the differences in CD4 molecules between teleosts and mammals. This review provides suggestions for further studies on the CD4 molecular function and regulatory mechanism of CD4+ helper T cells in teleost fish and will help establish therapeutic strategies to control fish diseases in the future.
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Affiliation(s)
- Hairong Tang
- College of Life Science, Henan Normal University, Henan Province, PR China; Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Henan Province, PR China
| | - Xinyu Jiang
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Henan Province, PR China
| | - Jie Zhang
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Henan Province, PR China
| | - Chao Pei
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Henan Province, PR China
| | - Xianliang Zhao
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Henan Province, PR China
| | - Li Li
- Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Henan Province, PR China
| | - Xianghui Kong
- College of Life Science, Henan Normal University, Henan Province, PR China; Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Henan Province, PR China.
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3
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Tissue and cell-type-specific transduction using rAAV vectors in lung diseases. J Mol Med (Berl) 2021; 99:1057-1071. [PMID: 34021360 DOI: 10.1007/s00109-021-02086-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 04/20/2021] [Accepted: 04/26/2021] [Indexed: 10/21/2022]
Abstract
Gene therapy of genetically determined diseases, including some pathologies of the respiratory system, requires an efficient method for transgene delivery. Recombinant adeno-associated viral (rAAV) vectors are well studied and employed in gene therapy, as they are relatively simple and low immunogenic and able to efficiently transduce eukaryotic cells. To date, many natural and artificial (with modified capsids) AAV serotypes have been isolated, demonstrating preferential tropism toward different tissues and cells in accordance with the prevalent receptors on the cell surface. However, rAAV-mediated delivery is not strictly specific due to wide tropism of some viral serotypes. Thus, the development of the methods allowing modulating specificity of these vectors could be beneficial in some cases. This review describes various approaches for retargeting rAAV to respiratory cells, for example, using different types of capsid modifications and regulation of a transgene expression by tissue-specific promoters. Part of the review is devoted to the issues of transduction of stem and progenitor lung cells using AAV, which is a complicated task today.
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Álvaro-Blanco J, Urso K, Chiodo Y, Martín-Cortázar C, Kourani O, Arco PGD, Rodríguez-Martínez M, Calonge E, Alcamí J, Redondo JM, Iglesias T, Campanero MR. MAZ induces MYB expression during the exit from quiescence via the E2F site in the MYB promoter. Nucleic Acids Res 2017; 45:9960-9975. [PMID: 28973440 PMCID: PMC5622404 DOI: 10.1093/nar/gkx641] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 07/13/2017] [Indexed: 12/27/2022] Open
Abstract
Most E2F-binding sites repress transcription through the recruitment of Retinoblastoma (RB) family members until the end of the G1 cell-cycle phase. Although the MYB promoter contains an E2F-binding site, its transcription is activated shortly after the exit from quiescence, before RB family members inactivation, by unknown mechanisms. We had previously uncovered a nuclear factor distinct from E2F, Myb-sp, whose DNA-binding site overlapped the E2F element and had hypothesized that this factor might overcome the transcriptional repression of MYB by E2F-RB family members. We have purified Myb-sp and discovered that Myc-associated zinc finger proteins (MAZ) are major components. We show that various MAZ isoforms are present in Myb-sp and activate transcription via the MYB-E2F element. Moreover, while forced RB or p130 expression repressed the activity of a luciferase reporter driven by the MYB-E2F element, co-expression of MAZ proteins not only reverted repression, but also activated transcription. Finally, we show that MAZ binds the MYB promoter in vivo, that its binding site is critical for MYB transactivation, and that MAZ knockdown inhibits MYB expression during the exit from quiescence. Together, these data indicate that MAZ is essential to bypass MYB promoter repression by RB family members and to induce MYB expression.
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Affiliation(s)
- Josué Álvaro-Blanco
- Department of Cancer Biology, Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, Madrid 28029, Spain
| | - Katia Urso
- Gene regulation in cardiovascular remodeling and inflammation group, Centro Nacional de Investigaciones Cardiovasculares, Madrid 28029, Spain
| | - Yuri Chiodo
- Department of Cancer Biology, Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, Madrid 28029, Spain
| | - Carla Martín-Cortázar
- Department of Cancer Biology, Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, Madrid 28029, Spain
| | - Omar Kourani
- Department of Cancer Biology, Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, Madrid 28029, Spain
| | - Pablo Gómez-Del Arco
- Gene regulation in cardiovascular remodeling and inflammation group, Centro Nacional de Investigaciones Cardiovasculares, Madrid 28029, Spain.,Department of Molecular Biology, Universidad Autónoma de Madrid, Centro de Biología Molecular, Cantoblanco, Madrid 28049, Spain.,CIBERCV, Spain
| | - María Rodríguez-Martínez
- Department of Cancer Biology, Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, Madrid 28029, Spain
| | - Esther Calonge
- Unidad de Inmunopatología del SIDA, Centro Nacional de Microbiología, Majadahonda 28220, Spain
| | - José Alcamí
- Unidad de Inmunopatología del SIDA, Centro Nacional de Microbiología, Majadahonda 28220, Spain
| | - Juan Miguel Redondo
- Gene regulation in cardiovascular remodeling and inflammation group, Centro Nacional de Investigaciones Cardiovasculares, Madrid 28029, Spain.,CIBERCV, Spain
| | - Teresa Iglesias
- Department of Endocrine and Nervous Systems Pathophysiology, Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, Madrid 28029, Spain.,CIBERNED, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Spain
| | - Miguel R Campanero
- Department of Cancer Biology, Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, Madrid 28029, Spain.,CIBERCV, Spain
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5
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Yu ZH, Lun SM, He R, Tian HP, Huang HJ, Wang QS, Li XQ, Feng YM. Dual function of MAZ mediated by FOXF2 in basal-like breast cancer: Promotion of proliferation and suppression of progression. Cancer Lett 2017; 402:142-152. [DOI: 10.1016/j.canlet.2017.05.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 05/03/2017] [Accepted: 05/24/2017] [Indexed: 11/16/2022]
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Akt phosphorylates myc-associated zinc finger protein (MAZ), releases P-MAZ from the p53 promoter, and activates p53 transcription. Cancer Lett 2016; 375:9-19. [DOI: 10.1016/j.canlet.2016.02.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 02/12/2016] [Accepted: 02/12/2016] [Indexed: 11/21/2022]
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7
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Lee KH, Lim D, Green T, Greenhalgh D, Cho K. Injury-elicited stressors alter endogenous retrovirus expression in lymphocytes depending on cell type and source lymphoid organ. BMC Immunol 2013; 14:2. [PMID: 23289855 PMCID: PMC3562510 DOI: 10.1186/1471-2172-14-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 12/11/2012] [Indexed: 11/10/2022] Open
Abstract
Background Murine leukemia virus-type endogenous retroviruses (MuLV-ERVs) constitute ~10% of the mouse genome and are associated with various pathophysiologic processes. In this study, we examined whether MuLV-ERVs’ response to burn-elicited stressors is specific for certain lymphocyte populations and/or locations of lymphoid organ. Results B- and T-cells, which were sorted from nine lymphoid organs of C57BL/6J mice after burn, were subjected to MuLV-ERV expression analyses. Overall, the post-burn MuLV-ERV expression pattern was dependent on lymphocyte type, time after injury, location of lymphoid organ, and MuLV-ERV type. For instance, the MuLV-ERV expression in T-cells from the thymus and three cervical lymph nodes decreased at 3 hours post-burn while the expression of some MuLV-ERVs was augmented in B-cells derived from the mesenteric lymph node. The MuLV-ERV U3 sequences population of the burn-24 hours group was less diverse in comparison to the no burn and burn-3 hours groups. In addition, it was apparent that at the 24 hours time point, the U3 populations of B-cells from both no burn and burn groups were less heterogeneous than the T-cells’ U3 populations. Using the U3 sequences, some of which were isolated only from specific experimental groups (B- vs. T-cells; no burn vs. burn), as probes, 51 putative MuLV-ERVs, including 16 full-length proviruses, were mapped followed by characterization of their biologic properties. Conclusion MuLV-ERVs’ response to burn-elicited stressors may be differentially controlled depending on lymphocyte type, location of lymphoid organ, MuLV-ERV type, and stress duration.
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Affiliation(s)
- Kang-Hoon Lee
- Department of Surgery, Burn Research, Shriners Hospitals for Children Northern California, University of California, Davis, Sacramento, CA 95817, USA
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Himeda CL, Ranish JA, Hauschka SD. Quantitative proteomic identification of MAZ as a transcriptional regulator of muscle-specific genes in skeletal and cardiac myocytes. Mol Cell Biol 2008; 28:6521-35. [PMID: 18710939 PMCID: PMC2577440 DOI: 10.1128/mcb.00306-08] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 03/23/2008] [Accepted: 08/09/2008] [Indexed: 11/20/2022] Open
Abstract
We identified a conserved sequence within the Muscle creatine kinase (MCK) promoter that is critical for high-level activity in skeletal and cardiac myocytes (MCK Promoter Element X [MPEX]). After selectively enriching for MPEX-binding factor(s) (MPEX-BFs), ICAT-based quantitative proteomics was used to identify MPEX-BF candidates, one of which was MAZ (Myc-associated zinc finger protein). MAZ transactivates the MCK promoter and binds the MPEX site in vitro, and chromatin immunoprecipitation analysis demonstrates enrichment of MAZ at the endogenous MCK promoter and other muscle gene promoters (Skeletal alpha-actin, Desmin, and alpha-Myosin heavy chain) in skeletal and cardiac myocytes. Consistent with its role in muscle gene transcription, MAZ transcripts and DNA-binding activity are upregulated during skeletal myocyte differentiation. Furthermore, MAZ was shown to bind numerous sequences (e.g., CTCCTCCC and CTCCACCC) that diverge from the GA box binding motif. Alternate motifs were identified in many muscle promoters, including Myogenin and MEF2C, and one motif was shown to be critical for Six4 promoter activity in both skeletal and cardiac myocytes. Interestingly, MAZ occupies and is able to transactivate the Six4 promoter in skeletal but not cardiac myocytes. Taken together, these findings are consistent with a previously unrecognized role for MAZ in muscle gene regulation.
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Affiliation(s)
- Charis L Himeda
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
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Nucleoprotein structure of the CD4 locus: implications for the mechanisms underlying CD4 regulation during T cell development. Proc Natl Acad Sci U S A 2008; 105:3873-8. [PMID: 18322012 DOI: 10.1073/pnas.0800810105] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The CD4 gene is regulated in a stage-specific manner during T cell development, being repressed in CD4(-)CD8(-) double-negative (DN) and CD8 cells, but expressed in CD4(+)CD8(+) double-positive (DP) and CD4 cells. Furthermore, the expression/repression pattern is reversible in developing (DN and DP) thymocytes, but irreversible in mature (CD4 and CD8) T cells. Here, we explored the molecular mechanisms underlying this complex mode of regulation by examining the nucleoprotein structure of the CD4 locus throughout T cell development and in DN cells lacking the CD4 silencer. In DN cells, the CD4 enhancer is preloaded with multiple transcription activators, but p300 recruitment is impaired by the silencer that is associated with the repressor Runx1. DP cells achieve high-level CD4 expression via a combination of CD4 derepression and true activation, but Runx1 remains bound to the silencer that retains an open chromatin configuration. In CD4 cells, Runx1 dissociates from the silencer that has become less accessible, and CD4 transcription appears to be achieved via a mechanism distinct from that operating in DP cells. In CD8 cells, the CD4 promoter becomes incorporated into heterochromatin-like structure. Our data shed light on the molecular basis of CD4 regulation and provide a conceptual framework for understanding how the same regulatory elements can mediate both reversible and irreversible CD4 regulation.
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11
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Wang HY, Chang HT, Pai TW, Wu CI, Lee YH, Chang YH, Tai HL, Tang CY, Chou WY, Chang MDT. Transcriptional regulation of human eosinophil RNases by an evolutionary- conserved sequence motif in primate genome. BMC Mol Biol 2007; 8:89. [PMID: 17927842 PMCID: PMC2174947 DOI: 10.1186/1471-2199-8-89] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Accepted: 10/11/2007] [Indexed: 11/24/2022] Open
Abstract
Background Human eosinophil-derived neurotoxin (edn) and eosinophil cationic protein (ecp) are members of a subfamily of primate ribonuclease (rnase) genes. Although they are generated by gene duplication event, distinct edn and ecp expression profile in various tissues have been reported. Results In this study, we obtained the upstream promoter sequences of several representative primate eosinophil rnases. Bioinformatic analysis revealed the presence of a shared 34-nucleotide (nt) sequence stretch located at -81 to -48 in all edn promoters and macaque ecp promoter. Such a unique sequence motif constituted a region essential for transactivation of human edn in hepatocellular carcinoma cells. Gel electrophoretic mobility shift assay, transient transfection and scanning mutagenesis experiments allowed us to identify binding sites for two transcription factors, Myc-associated zinc finger protein (MAZ) and SV-40 protein-1 (Sp1), within the 34-nt segment. Subsequent in vitro and in vivo binding assays demonstrated a direct molecular interaction between this 34-nt region and MAZ and Sp1. Interestingly, overexpression of MAZ and Sp1 respectively repressed and enhanced edn promoter activity. The regulatory transactivation motif was mapped to the evolutionarily conserved -74/-65 region of the edn promoter, which was guanidine-rich and critical for recognition by both transcription factors. Conclusion Our results provide the first direct evidence that MAZ and Sp1 play important roles on the transcriptional activation of the human edn promoter through specific binding to a 34-nt segment present in representative primate eosinophil rnase promoters.
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Affiliation(s)
- Hsiu-Yu Wang
- Institute of Molecular and Cellular Biology & Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan 30013, Republic of China.
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Su JM, Lai XM, Lan KH, Li CP, Chao Y, Yen SH, Chang FY, Lee SD, Lee WP. X protein of hepatitis B virus functions as a transcriptional corepressor on the human telomerase promoter. Hepatology 2007; 46:402-13. [PMID: 17559154 DOI: 10.1002/hep.21675] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
UNLABELLED The X protein of hepatitis B virus (HBx) is essential for transactivation of hepatitis B viral and host cellular genes. It has been specifically implicated in the development of hepatocellular carcinoma; however, the molecular mechanism remains unknown. Telomeres, the DNA-protein complexes at the ends of eukaryotic chromosomes, protect chromosomes from degradation at the terminal regions, fusion with a broken DNA end, and inappropriate recombination. The shortening of telomeres that occurs during hepatocellular carcinogenesis has been well studied. In the present study, we isolated an HBx isoform that resulted in telomere shortening in hepatoma cell lines. We found that this HBx isoform down-regulated the expression of human telomerase by transcriptionally repressing its promoter. To further determine the molecular mechanism, we examined human telomerase promoter and identified myc-associated zinc finger protein (MAZ) as a transcriptional repressor of the promoter. We found that the HBx isoform achieved transcriptional suppression of human telomerase by enhancing MAZ binding to its consensus sequence in the promoter through physical association with MAZ. CONCLUSION The data suggest that HBx can induce telomere shortening by acting as a transcriptional corepressor of MAZ on the human telomerase promoter.
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Affiliation(s)
- Jiun-Ming Su
- Institute of Biochemistry and Molecular Biology, School of Life Sciences, National Yang-Ming University, Taipei, Taiwan
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Ericsson A, Kotarsky K, Svensson M, Sigvardsson M, Agace W. Functional characterization of the CCL25 promoter in small intestinal epithelial cells suggests a regulatory role for caudal-related homeobox (Cdx) transcription factors. THE JOURNAL OF IMMUNOLOGY 2006; 176:3642-51. [PMID: 16517733 DOI: 10.4049/jimmunol.176.6.3642] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The chemokine CCL25 is selectively and constitutively expressed in the small intestinal epithelium and plays an important role in mediating lymphocyte recruitment to this site. In this study, we demonstrate that CCL25 expression in murine small intestinal epithelial cells is independent of signaling through the lymphotoxin beta receptor and is not enhanced by inflammatory stimuli, pathways involved in driving the expression of most other chemokines. We define a transcriptional start site in the CCL25 gene and a region -141 to -5 proximal of exon 1 that is required for minimal promoter activity in the small intestinal epithelial cell lines, MODE-K and mICc12. These cell lines expressed far less CCL25 mRNA than freshly isolated small intestinal epithelial cells indicating that they are missing important factors driving CCL25 expression. The CCL25 promoter contained putative binding sites for the intestinal epithelial-associated Caudal-related homeobox (Cdx) transcription factors Cdx-1 and Cdx-2, and small intestinal epithelial cells but not MODE-K and mICc12 cells expressed Cdx-1 and Cdx-2. EMSA analysis demonstrated that Cdx proteins were present in nuclear extracts from freshly isolated small intestinal epithelial cells but not in MODE-K or mICcl2 cells, and bound to putative Cdx sites within the CCL25 promoter. Finally, cotransfection of MODE-K cells with Cdx transcription factors significantly increased CCL25 promoter activity as well as endogenous CCL25 mRNA levels. Together these results demonstrate a unique pattern of regulation for CCL25 and suggest a role for Cdx proteins in regulating CCL25 transcription.
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Affiliation(s)
- Anna Ericsson
- Immunology Section, Stem Cell Center, Biomedical Centre I-13, Lund University, S-22184 Lund, Sweden
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Ray A, Kumar D, Ray P, Ray BK. Transcriptional activity of serum amyloid A-activating factor-1 is regulated by distinct functional modules. J Biol Chem 2004; 279:54637-46. [PMID: 15498774 DOI: 10.1074/jbc.m411830200] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Serum amyloid A-activating transcription factor-1 (SAF-1) plays a major role in regulating transcription of several inflammation-responsive genes, including SAA and matrix metalloproteinase-1, that are implicated in the pathogenesis of reactive secondary amyloidosis, atherosclerosis, and arthritis. SAF-1 is a 477-amino acid protein with six zinc fingers. Its activation during inflammatory condition by a phosphorylation event that leads to an altered structure suggested possible structural modification of this protein as a leading cause of higher activity. However, no information is available regarding structural features that might regulate its activity. Here, we have characterized its functional domains, delineating activation and repression modules, DNA binding, and nuclear localization activities. Using GAL4AD chimeras and a DNA-binding assay with proteins prepared from various deletion constructs, the core DNA-binding domain of SAF-1 is mapped between amino acids 282 and 361, which contain second, third, and fourth zinc fingers. Results from several deletion and point mutants using green fluorescent protein reporter show that SAF-1 contains two independent nuclear localization signals; one is composed of a stretch of basic amino acids, and the other is a bipartite signal located within the core DNA-binding domain. SAF-1 contains several negative and positively functioning transactivation modules clustered at the two ends of this protein. Removal of any one of the terminal negative modules renders the SAF-1 protein functionally very active. These findings suggest that the terminal repression modules act in conjunction to regulate the functional activity of this protein.
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Affiliation(s)
- Alpana Ray
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri 65211, USA
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Ray A, Shakya A, Kumar D, Ray BK. Overexpression of serum amyloid A-activating factor 1 inhibits cell proliferation by the induction of cyclin-dependent protein kinase inhibitor p21WAF-1/Cip-1/Sdi-1 expression. THE JOURNAL OF IMMUNOLOGY 2004; 172:5006-15. [PMID: 15067082 DOI: 10.4049/jimmunol.172.8.5006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Inflammation-responsive transcription factor, serum amyloid A-activating factor 1 (SAF-1), has been shown to regulate several genes, including serum amyloid A, gamma-fibrinogen, and matrix metalloproteinase 1, whose abnormal expression is associated with the pathogenesis of arthritis, atherosclerosis, and amyloidosis. Prolonged high level expression of SAF-1 in cultured cells failed to produce any stable cell line that overexpresses SAF-1. To test the fate of SAF-1-overexpressing cells, the cells were monitored for growth and morphological changes over time. The cells that were programmed to overproduce SAF-1 were found to undergo growth arrest and reduce DNA synthesis within 3 days after transfection. These cells undergo marked morphological changes from typical fibroblasts to round morphology and gradually cease to exist. Microarray analysis for cell cycle-specific genes in SAF1-transfected cells identified several candidate genes whose expression levels were altered during SAF-1 overexpression. Cdk inhibitor protein p21 was significantly affected by SAF-1; its expression level was highly induced by cellular conditions where SAF-1 is abundant. The increased level of p21 in the cell drives it to a growth arrest mode, a condition previously found to be controlled by p53. In this study we provide evidence that, similar to p53, SAF-1 is able to activate p21 gene expression by promoting transcription directly via its interaction with the p21 promoter. Together these data indicate that SAF-1 controls cell cycle progression via p21 induction, and pathophysiological conditions that favor overexpression of SAF-1, such as an acute inflammatory condition, can trigger cellular growth arrest.
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Affiliation(s)
- Alpana Ray
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA.
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Her S, Claycomb R, Tai TC, Wong DL. Regulation of the Rat PhenylethanolamineN-Methyltransferase Gene by Transcription Factors Sp1 and MAZ. Mol Pharmacol 2003; 64:1180-8. [PMID: 14573768 DOI: 10.1124/mol.64.5.1180] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The rat phenylethanolamine N-methyltransferase (PNMT) gene promoter contains 1-base pair (bp) overlapping consensus sequences for Sp1 and MAZ transcription factors at -48 and -38 bp, respectively. Gel mobility assays using PC-12-derived RS1 cell nuclear extracts or in vitro translated proteins showed that Sp1 and MAZ specifically bind to these elements, that MAZ displaces/prevents Sp1 binding, and that Sp1 and MAZ binding is mutually exclusive, with occupancy dependent on each factor's concentration and affinity for its consensus element. In transfection assays, PNMT promoter activation by Sp1 and MAZ depends on promoter length, with -893 bp of sequence yielding greatest activation. Although MAZ has higher affinity for its binding element, it is a less effective activator. Changes in PNMT promoter activity for the constructs pGL3RP60 or pGL3RP893 using a fixed amount of MAZ expression construct and a variable amount of Sp1 expression construct or vice versa confirmed the latter. Mutation of the MAZ or Sp1 sites in pGL3RP60 attenuated but did not eliminate PNMT promoter activity, even though the proteins no longer bind to their consensus elements. Phosphatase treatment of RS1 cell nuclear extracts prevented MAZ- and Sp1-DNA binding complex formation. Although MAZ and Sp1 elevate endogenous PNMT mRNA in RS1 cells, MAZ preferentially increases intron-retaining whereas Sp1 preferentially increases intronless mRNA. Thus, expression of the PNMT gene seems to be modulated through competitive binding of phosphorylated Sp1 and MAZ to their consensus elements in the promoter. In addition, post-transcriptional regulation seems to be another important mechanism controlling PNMT expression.
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Affiliation(s)
- Song Her
- Department of Psychiatry, Harvard Medical School Laboratory of Molecular and Developmental Neurobiology, McLean Hospital, 115 Mill Street, Rm 116, Belmont, MA 02478, USA
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17
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Ray A, Ray P, Guthrie N, Shakya A, Kumar D, Ray BK. Protein kinase A signaling pathway regulates transcriptional activity of SAF-1 by unmasking its DNA-binding domains. J Biol Chem 2003; 278:22586-95. [PMID: 12697757 DOI: 10.1074/jbc.m300705200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Serum amyloid A (SAA) activating factor-1 (SAF-1) is an inducible transcription factor that plays a key role in the regulation of several inflammation-responsive genes including SAA and matrix metalloproteinase-1. Increased synthesis of SAA and matrix metalloproteinase-1 is associated with pathogenesis of several diseases including amyloidosis, arthritis, and atherosclerosis. Previously, we showed in vivo interaction of SAF-1 and protein kinase A (PKA) and presented evidence for induction of SAF-1-regulated genes by a PKA signaling pathway. Here we demonstrate a mechanism by which PKA increases functional activities of SAF-1. Site-directed mutagenesis and phosphorylation analyses revealed two sites in the SAF-1 protein, serine 187 and threonine 386, as the target of PKA. Interestingly, mutation of both PKA phosphorylation sites created a highly active SAF-1 protein with high DNA-binding ability. Furthermore, we found that terminal deletion of SAF-1 protein from either end creates SAF-1 isoforms that are highly transcriptionally active. Partial proteolysis experiments indicated that unphosphorylated and phosphorylated SAF-1 proteins are structurally distinct. Together these results suggest that under native condition, N and C termini of SAF-1 are engaged in an inhibitory intramolecular interaction. PKA-mediated phosphorylation increases transcriptional activity of SAF-1 by unmasking the DNA-binding domain.
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Affiliation(s)
- Alpana Ray
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri 65211, USA.
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18
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Abstract
T cell lineage commitment as the double-positive (DP) thymocyte matures into the single-positive (SP) T cell requires the irreversible repression or maintenance of CD4 gene expression. Signals transmitted from the T cell antigen receptor (TCR) during thymic selection are believed to be linked to the transcriptional regulation of the CD4 gene; thus, a study of the factors that control CD4 gene expression may lead to further insight into the molecular mechanisms that drive T cell development. This review discusses the work conducted to date to identify and characterize the transcriptional control elements in the CD4 locus and the factors that mediate their function. From these studies, it is clear that the molecular mechanisms controlling CD4 gene expression are very complex and are controlled by many different signals as the thymocyte develops.
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Affiliation(s)
- Gerald Siu
- Department of Microbiology, College of Physicians and Surgeons, Columbia University, 701 West 168th Street, New York, NY 10032, USA.
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19
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Ray BK, Murphy R, Ray P, Ray A. SAF-2, a splice variant of SAF-1, acts as a negative regulator of transcription. J Biol Chem 2002; 277:46822-30. [PMID: 12270922 DOI: 10.1074/jbc.m206299200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Serum amyloid A-activating factor-1 (SAF-1), a Cys(2)His(2)-type zinc finger transcription factor, regulates inflammation-induced expression of serum amyloid A protein that is linked to the pathogenesis of reactive amyloidosis, rheumatoid arthritis, and atherosclerosis. Here we report the identification of a novel splice variant, SAF-2, of the SAF family bearing strong sequence similarity to SAF-1. The N-terminal 426 amino acids of both SAF-1 and SAF-2 are identical containing two polyalanine tracts, one proline-rich domain, and six zinc fingers. However, the C terminus of SAF-2 containing two additional zinc fingers is different from SAF-1, which indicates the capability of different biochemical function. We show that SAF-2 interacts more avidly with the SAF-binding element, but its transactivation potential is much lower than SAF-1. Furthermore, co-expression of SAF-2 markedly suppresses SAF-1-regulated promoter function. Finally, we show that the level of SAF-2 protein is reduced during many inflammatory conditions, whereas the SAF-1 protein level remains unchanged. Together, these data suggest that the relative abundance of SAF-2 plays a critical role in the fine tuned regulation of inflammation-responsive genes that are controlled by SAF-1.
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Affiliation(s)
- Bimal K Ray
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri 65211.
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20
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Ray A, Yu GY, Ray BK. Cytokine-responsive induction of SAF-1 activity is mediated by a mitogen-activated protein kinase signaling pathway. Mol Cell Biol 2002; 22:1027-35. [PMID: 11809795 PMCID: PMC134650 DOI: 10.1128/mcb.22.4.1027-1035.2002] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
SAF-1, a zinc finger transcription factor, is activated by a number of inflammatory agents, including interleukin-1 (IL-1) and IL-6. It is involved in the cytokine-mediated transcriptional induction of serum amyloid A, an acute-phase plasma protein that is associated with the pathogenesis of reactive amyloidosis, rheumatoid arthritis, and atherosclerosis. Here, we show that the mitogen-activated protein (MAP) kinase signaling pathway regulates cytokine-mediated induction of the DNA-binding activity and transactivation potential of SAF-1. Phosphorylation of endogenous SAF-1 in response to IL-1 and IL-6 was markedly inhibited by the addition of MAP kinase inhibitors. Consistent with this finding, we show that a consensus MAP kinase phosphorylation site, PPTP, within SAF-1 could be phosphorylated by MAP kinase in vitro. To analyze the contribution of MAP kinase in the activation of SAF-1, we prepared two independent mutant proteins in which the threonine residue of the PPTP motif was altered to either valine or alanine. These mutant proteins lost the ability to be phosphorylated by MAP kinase both in vivo and in vitro and exhibited a significantly reduced ability to promote expression of the SAF-1-regulated promoter. While the DNA-binding activity of wild-type SAF-1 protein was markedly increased upon phosphorylation with MAP kinase, no such increase could be detected with the mutant SAF-1 proteins. Further analysis with the GAL-4 reporter system showed that mutation of the MAP kinase phosphorylation site considerably lowers the transactivation potential of SAF-1. Together, these results show that activation of SAF-1 in response to IL-1 and -6 is mediated via MAP kinase-regulated phosphorylation.
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Affiliation(s)
- Alpana Ray
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri 65211, USA.
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21
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Ray A, Kumar D, Ray BK. Promoter-binding activity of inflammation-responsive transcription factor SAF is regulated by cyclic AMP signaling pathway. DNA Cell Biol 2002; 21:31-40. [PMID: 11879578 DOI: 10.1089/10445490252810294] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The serum amyloid A activating factor (SAF) was identified as a family of inducible transcription factors that is activated by many mediators of inflammation. Its activation involves a phosphorylation event, whose mechanism is not fully understood. Here, we show that cAMP treatment of several cell types, including mouse liver-derived BNL CL.2, human monocyte-derived THP-1, and a primary culture of vascular smooth muscle cells from porcine aorta, activated cellular SAF's ability to bind DNA. The protein kinase A (PKA) activity in cytoplasmic extracts of cAMP-treated cells was responsible for the potentiation of the DNA-binding activity of the cellular SAF proteins. Furthermore, treatment of nuclear extracts of untreated cells with purified PKA increased the DNA-binding activity of cellular SAF proteins, and specific inhibitors of PKA abrogated the enhanced DNA-binding ability of SAF in the cAMP-treated cells. Consistent with these findings, overexpression of the catalytic subunit of PKA markedly increased expression of the SAF-regulated promoter. These results imply a functional role for the previously detected protein-protein interaction between SAF-1 transcription factor and the catalytic subunit of PKA and further demonstrate the consequences of cAMP-mediated signaling for the expression of SAF-regulated genes.
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Affiliation(s)
- Alpana Ray
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri 65211, USA
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22
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Hanna Z, Rebai N, Poudrier J, Jolicoeur P. Distinct regulatory elements are required for faithful expression of human CD4 in T cells, macrophages, and dendritic cells of transgenic mice. Blood 2001; 98:2275-8. [PMID: 11568018 DOI: 10.1182/blood.v98.7.2275] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To identify the regulatory elements controlling expression of the human CD4 (hCD4) gene in different cell types of the immune system, deletion and chimeric (human/murine) reporter genes were constructed and tested in transgenic (Tg) mice. Regulatory elements required for the proper hCD4 expression in the immature double-positive thymic T cells were identified in the enhancer and in the 3' end of intron 1. Expression of hCD4 in macrophages is controlled by at least 2 sets of regulatory elements: one present in front of exon 1 and the second at the 5' end of intron 1. The hCD4 elements required for expression on both myeloid and lymphoid CD8alpha(+) dendritic cells (DCs) from lymph node and thymus were found to be different from those required for macrophage expression. The results indicate that expression of hCD4 in T cells, macrophages, and DCs is controlled by distinct regulatory elements.
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Affiliation(s)
- Z Hanna
- Laboratory of Molecular Biology, Clinical Research Institute of Montreal, Montreal, Quebec, Canada.
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23
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Kawane T, Mimura J, Fujii-Kuriyama Y, Horiuchi N. Parathyroid hormone (PTH) suppresses rat PTH/PTH-related protein receptor gene promoter. Biochem Biophys Res Commun 2001; 287:313-22. [PMID: 11554727 DOI: 10.1006/bbrc.2001.5586] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Parathyroid hormone (PTH) regulates osteoblasts via a G protein-linked PTH/PTH-related protein (PTHrP) receptor. PTH effects on PTH/PTHrP receptor gene expression were studied in UMR 106 osteoblast-like cells. In heterogeneous nuclear RNA and Northern analysis, PTH suppressed PTH/PTHrP receptor transcription. We cloned the 7-kb promoter region of the rat PTH/PTHrP receptor gene and transiently transfected chimeric deletion constructs containing the 5'-flanking region and the luciferase gene into UMR 106 cells. In transfected cells the minimal region for basal promoter activity was between positions -128 and +103. The 5'-flanking region of exon U1 contained several putative-binding sites for Sp1 and the myc-associated zinc finger protein (MAZ). The minimal PTH-suppressive region (PTHSR) was between +1 and +25 in exon U1, but the 5'-flanking region or Sp1 and MAZ-binding sites also were required for PTH-mediated repression. By gel mobility shift assay PTH markedly decreased binding of PTHSR-protein complex in UMR 106 cells. The mutation experiments showed that the most critical sequence for the repression of PTH was 5'-GGGGGAGGGGAG-3' (+1 to +12) of PTHSR. This represents the first characterization of a PTH-suppressive region of the PTH/PTHrP receptor gene in rat.
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Affiliation(s)
- T Kawane
- Department of Biochemistry, Ohu University School of Dentistry, Koriyama 963-8611, Japan
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24
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Bryl E, Vallejo AN, Weyand CM, Goronzy JJ. Down-regulation of CD28 expression by TNF-alpha. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:3231-8. [PMID: 11544310 DOI: 10.4049/jimmunol.167.6.3231] [Citation(s) in RCA: 191] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Aging and chronic inflammatory syndromes, such as rheumatoid arthritis, are associated with high frequencies of CD4(+)CD28(null) T cells, which are rarely seen in healthy individuals younger than 40 years. Inasmuch as rheumatoid arthritis and aging are also associated with elevated levels of TNF-alpha, we examined whether this proinflammatory cytokine influences CD28 expression. Incubation of T cell lines and clones as well as Jurkat cells with TNF-alpha induced a reduction in the levels of cell surface expression of CD28. This effect of TNF-alpha was reversible; however, continuous culture of CD4(+)CD28(+) T cell clones in TNF-alpha resulted in the appearance of a CD28(null) subset. In reporter gene bioassays, TNF-alpha was found to inhibit the activity of the CD28 minimal promoter. Inactivation of the promoter was accompanied by a marked reduction in DNA-protein complex formation by two DNA sequence motifs corresponding to the transcriptional initiator of the CD28 gene. Indeed, in vitro transcription assays showed that nuclear extracts from TNF-alpha-treated cells failed to activate transcription of DNA templates under the control of a consensus TATA box and the CD28 initiator sequences. In contrast, similar extracts from unstimulated T cells supported transcription. These results demonstrate that TNF-alpha directly influences CD28 gene transcription. We propose that the emergence of CD4(+)CD28(null) T cells in vivo is facilitated by increased production of TNF-alpha.
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Affiliation(s)
- E Bryl
- Department of Medicine and Immunology, Mayo Clinic, Rochester, MN 55905, USA
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25
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Ugai H, Li HO, Komatsu M, Tsutsui H, Song J, Shiga T, Fearon E, Murata T, Yokoyama KK. Interaction of Myc-associated zinc finger protein with DCC, the product of a tumor-suppressor gene, during the neural differentiation of P19 EC cells. Biochem Biophys Res Commun 2001; 286:1087-97. [PMID: 11527412 DOI: 10.1006/bbrc.2001.5469] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Expression of the DCC (deleted in colorectal cancer) protein is strongly induced during the neural differentiation of mouse P19 embryonal carcinoma (EC) cells that occurs when these cells are treated with retinoic acid (RA). Myc-associated zinc finger protein (MAZ) is a DNA-binding protein that is widely expressed and functions in human, mouse and hamster cells as an activator, an initiator or a terminator of transcription. However, the biological functions of MAZ remain elusive. We report here that MAZ associates with the cytoplasmic domain of the DCC protein in vivo and in vitro. Yeast two-hybrid assays confirmed this association. An immunofluorescence study demonstrated that DCC protein is expressed at elevated levels in neuron-like P19 EC cells, in particular in axons, in which the MAZ protein is also expressed. We found that MAZ was translocated from the nucleus to the cytoplasm during the RA-induced terminal differentiation of P19 EC cells with resultant loss of the ability of MAZ to bind to the ME1a1 site of the c-myc promoter. Taken together, our observations imply that the DCC protein might play a critical role as a signaling molecule in the regulation of the transcriptional activity of MAZ during the neural differentiation of P19 EC cells.
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MESH Headings
- Active Transport, Cell Nucleus
- Amino Acid Sequence
- Animals
- Binding Sites
- Blotting, Northern
- Blotting, Western
- Cell Adhesion Molecules/metabolism
- Cell Differentiation
- Cell Line
- Cell Nucleus/metabolism
- Cytoplasm/metabolism
- DCC Receptor
- DNA-Binding Proteins
- Genes, myc/genetics
- Humans
- Immunohistochemistry
- Microscopy, Fluorescence
- Models, Biological
- Molecular Sequence Data
- Neurons/metabolism
- Plasmids/metabolism
- Precipitin Tests
- Promoter Regions, Genetic
- Protein Binding
- Protein Structure, Tertiary
- RNA/metabolism
- RNA, Messenger/metabolism
- Receptors, Cell Surface
- Recombinant Fusion Proteins/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Amino Acid
- Signal Transduction
- Time Factors
- Transcription Factors/metabolism
- Transcription, Genetic
- Transfection
- Tretinoin/metabolism
- Tumor Suppressor Proteins
- Two-Hybrid System Techniques
- Xenopus
- Zinc Fingers
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Affiliation(s)
- H Ugai
- Gene Engineering Division, Bioresource Center, Tsukuba Institute, RIKEN (The Institute of Physical and Chemical Research), 3-1-1 Koyadai, Tsukuba, Ibaraki, 305-0074, Japan
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26
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Ray BK, Chen J, Ray A. Catalytic subunit of protein kinase A is an interacting partner of the inflammation-responsive transcription factor serum amyloid A-activating factor-1. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:2343-8. [PMID: 11490023 DOI: 10.4049/jimmunol.167.4.2343] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Serum amyloid A-activating factor-1 (SAF-1) is a zinc finger transcription factor that is activated by many mediators of inflammation including IL-1, IL-6, and bacterial LPS. However, the mechanism of activation is not fully understood. To identify possible activation partners for SAF-1, we used a yeast two-hybrid system that detected interaction between the catalytic subunit of cyclic AMP-dependent protein kinase (PKA-Calpha) and SAF-1. Immunofluorescence and combined immunoprecipitation-Western blot analyses revealed colocalization and interaction between SAF-1 and PKA-Calpha. In vivo evidence of SAF-1 and PKA-Calpha interaction was further revealed by coimmunoprecipitation of these two proteins in cAMP-activated liver cells. We further show that SAF-1 is phosphorylated in vitro by PKA-Calpha and that addition of cAMP markedly induces in vivo phosphorylation of SAF-1 and transcription of SAF-regulated reporter genes. These results showed that SAF1-PKA-Calpha interaction is involved in functional activation of SAF-1.
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Affiliation(s)
- B K Ray
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
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27
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Song J, Ugai H, Ogawa K, Wang Y, Sarai A, Obata Y, Kanazawa I, Sun K, Itakura K, Yokoyama KK. Two consecutive zinc fingers in Sp1 and in MAZ are essential for interactions with cis-elements. J Biol Chem 2001; 276:30429-34. [PMID: 11395515 DOI: 10.1074/jbc.m103968200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The zinc finger proteins Sp1 and Myc-associated zinc finger protein (MAZ) are transcription factors that control the expression of various genes. Regulation of transcription by these factors is based on interactions between GC-rich DNA-binding sites (GGGCGG for Sp1 and GGGAGGG for MAZ) and the carboxyl-terminal zinc finger motifs of the two proteins. Sp1 and MAZ have three and six zinc fingers, respectively, and the details of their interactions with cis-elements remain to be clarified. We demonstrate here that Sp1 and MAZ interact with the same GC-rich DNA-binding sites, apparently sharing DNA-binding sites with each other. We found that the DNA binding activities of Sp1 and MAZ depended mainly on consecutive zinc fingers, namely the second and third zinc fingers in Sp1 and the third and fourth zinc fingers in MAZ. Furthermore, the interactions of the zinc finger proteins with the same cis-elements appear to play a critical role in the regulation of gene expression. It seems plausible that two consecutive zinc finger motifs in a zinc finger protein might be essential for interaction of the protein with DNA.
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Affiliation(s)
- J Song
- RIKEN (The Institute of Physical and Chemical Research), Tsukuba Institute, Bioresource Center, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan
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28
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Uchida S, Sasaki S, Marumo F. Isolation of a novel zinc finger repressor that regulates the kidney-specific CLC-K1 promoter. Kidney Int 2001; 60:416-21. [PMID: 11473619 DOI: 10.1046/j.1523-1755.2001.060002416.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
CLC-K1 and CLC-K2, two kidney-specific CLC chloride channels, are transcriptionally regulated on a tissue-specific basis. We have shown that a GA element near their transcriptional start sites is important for basal and cell-specific activities of the CLC-K1 and CLC-K2 gene promoters. To identify the GA-binding proteins, a kidney cDNA library was screened by a yeast one-hybrid system. A novel member of the Cys2-His2 zinc finger gene designated as KKLF (kidney-enriched Krüppel-like factor) and the myc-associated zinc finger protein (MAZ) were cloned. KKLF was found to be abundantly expressed in the liver, kidney, heart, and skeletal muscle. In the kidney, KKLF protein was localized in interstitial cells, mesangial cells, and nephron segments where CLC-K1 and CLC-K2 were not expressed. Gel mobility shift assay revealed that recombinant KKLF and MAZ proteins exhibited sequence-specific binding to the CLC-K1 GA element and that the consensus sequence for the KKLF binding site was GGGGNGGNG. In transient transfection, MAZ had a strong activating effect on the CLC-K1-luciferase reporter gene transcription. On the other hand, KKLF coexpression with MAZ appeared to block the activating effect of MAZ. These results suggest that a novel set of zinc finger proteins may help regulate the strict tissue and nephron segment-specific expression of CLC-K1 and CLC-K2 channel genes through their GA cis element.
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Affiliation(s)
- S Uchida
- Homeostasis Medicine and Nephrology, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
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29
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Albert T, Wells J, Funk JO, Pullner A, Raschke EE, Stelzer G, Meisterernst M, Farnham PJ, Eick D. The chromatin structure of the dual c-myc promoter P1/P2 is regulated by separate elements. J Biol Chem 2001; 276:20482-90. [PMID: 11279041 DOI: 10.1074/jbc.m100265200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The proto-oncogene c-myc is transcribed from a dual promoter P1/P2, with transcription initiation sites 160 base pairs apart. Here we have studied the transcriptional activation of both promoters on chromatin templates. c-myc chromatin was reconstituted on stably transfected, episomal, Epstein-Barr virus-derived vectors in a B cell line. Episomal P1 and P2 promoters showed only basal activity but were strongly inducible by histone deacetylase inhibitors. The effect of promoter mutations on c-myc activity, chromatin structure, and E2F binding was studied. The ME1a1 binding site between P1 and P2 was required for the maintenance of an open chromatin configuration of the dual c-myc promoters. Mutation of this site strongly reduced the sensitivity of the core promoter region of P1/P2 to micrococcal nuclease and prevented binding of polymerase II (pol II) at the P2 promoter. In contrast, mutation of the P2 TATA box also abolished binding of pol II at the P2 promoter but did not affect the chromatin structure of the P1/P2 core promoter region. The E2F binding site adjacent to ME1a1 is required for repression of the P2 promoter but not the P1 promoter, likely by recruitment of histone deacetylase activity. Chromatin precipitation experiments with E2F-specific antibodies revealed binding of E2F-1, E2F-2, and E2F-4 to the E2F site of the c-myc promoter in vivo if the E2F site was intact. Taken together, the analyses support a model with a functional hierarchy for regulatory elements in the c-myc promoter region; binding of proteins to the ME1a1 site provides a nucleosome-free region of chromatin near the P2 start site, binding of E2F results in transcriptional repression without affecting polymerase recruitment, and the TATA box is required for polymerase recruitment.
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Affiliation(s)
- T Albert
- Institute of Clinical Molecular Biology and Tumor Genetics, Department for Protein Chemistry, Research Centre for Environment and Health (GSF), Marchioninistrasse 25, D-81377 München, Germany
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30
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Song J, Ugai H, Kanazawa I, Sun K, Yokoyama KK. Independent repression of a GC-rich housekeeping gene by Sp1 and MAZ involves the same cis-elements. J Biol Chem 2001; 276:19897-904. [PMID: 11259406 DOI: 10.1074/jbc.m010658200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The transcription factors Sp1 and MAZ (Myc-associated zinc finger protein) contain several zinc finger motifs, and each functions as both a positive and a negative regulator of gene expression. In this study, we characterized the extremely GC-rich promoter of the human gene for MAZ, which is known as a housekeeping gene. Unique symmetrical motifs in the promoter region (nucleotides -383 to -334) were essential for the expression of the gene for MAZ, whereas an upstream silencer element (nucleotides -784 to -612) was found to act in a position-dependent but orientation-independent manner. Sp1 and MAZ bound to the same cis-elements in the GC-rich promoter, apparently sharing DNA-binding sites. The relative extent of binding of Sp1 and MAZ to these cis-elements corresponded to the extent of negative regulation of the expression of the gene for MAZ in various lines of cells. Furthermore, novel repressive domains in both Sp1 (amino acids 622-788) and MAZ (amino acids 127-292) were identified. Suppression by Sp1 and suppression by MAZ were independent phenomena; histone deacetylases were involved in the autorepression by MAZ itself, whereas DNA methyltransferase 1 was associated with suppression by Sp1. Our results indicate that both deacetylation and methylation might be involved in the regulation of expression of a single gene via the actions of different zinc finger proteins that bind to the same cis-elements.
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Affiliation(s)
- J Song
- RIKEN (The Insitute of Physical & Chemical Research), Tsukuba Institute, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan
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31
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Allen RD, Kim HK, Sarafova SD, Siu G. Negative regulation of CD4 gene expression by a HES-1-c-Myb complex. Mol Cell Biol 2001; 21:3071-82. [PMID: 11287612 PMCID: PMC86935 DOI: 10.1128/mcb.21.9.3071-3082.2001] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Expression of the CD4 gene is tightly controlled throughout thymopoiesis. The downregulation of CD4 gene expression in CD4(-) CD8(-) and CD4(-) CD8(+) T lymphocytes is controlled by a transcriptional silencer located in the first intron of the CD4 locus. Here, we determine that the c-Myb transcription factor binds to a functional site in the CD4 silencer. As c-Myb is also required for CD4 promoter function, these data indicate that depending on the context, c-Myb plays both positive and negative roles in the control of CD4 gene expression. Interestingly, a second CD4 silencer-binding factor, HES-1, binds to c-Myb in vivo and induces it to become a transcriptional repressor. We propose that the recruitment of HES-1 and c-Myb to the silencer leads to the formation of a multifactor complex that induces silencer function and repression of CD4 gene expression.
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Affiliation(s)
- R D Allen
- Department of Microbiology, Columbia University, College of Physicians and Surgeons, New York, New York 10032, USA
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32
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Vallejo AN, Weyand CM, Goronzy JJ. Functional disruption of the CD28 gene transcriptional initiator in senescent T cells. J Biol Chem 2001; 276:2565-70. [PMID: 11069899 DOI: 10.1074/jbc.m005503200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We recently reported that aging is accompanied by the emergence of CD4(+)CD28(null) T cells, a functionally aberrant lymphocyte subset rarely seen in individuals younger than 40 years. Here, we directly examined whether the lack of CD28 expression is due to a defect at the level of transcriptional initiation. Molecular studies reveal that CD28 gene transcription is controlled by two sequence motifs, sites alpha and beta. In vitro transcription assays using initiator-dependent DNA templates revealed that reversed polarity or the deletion of either motif inhibited transcription, indicating that alpha/beta sequences constitute a composite initiator. Moreover, nuclear extracts from CD28(null) cells failed to activate transcription of alphabeta-initiator DNA templates. Transcription of such templates was, however, restored with the addition of extracts from CD28(+) cells. Although previously described initiator elements have been defined by a consensus sequence, the alphabeta-initiator has no homology to such sequence. These studies demonstrate that initiators have functions other than positioning elements for the basal transcription complex. Rather, initiators can have a direct role in regulating the expression of specific genes. The gain or loss of initiator activity can be an important determinant of cell phenotypes.
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Affiliation(s)
- A N Vallejo
- Departments of Medicine and Immunology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA.
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33
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Ray A, Fields AP, Ray BK. Activation of transcription factor SAF involves its phosphorylation by protein kinase C. J Biol Chem 2000; 275:39727-33. [PMID: 10995778 DOI: 10.1074/jbc.m007907200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The transcription factor serum amyloid A (SAA)-activating factor (SAF), a family of zinc finger proteins, plays a significant role in the induced expression of the SAA gene. Activity of SAF is regulated by a phosphorylation event involving serine/threonine protein kinase (Ray, A., Schatten, H., and Ray, B. K. (1999) J. Biol. Chem. 274, 4300-4308; Ray, A., and Ray, B. K. (1998) Mol. Cell. Biol. 18, 7327-7335). However, the identity of the protein kinase has so far remained unknown. Induction of SAA by phorbol 12-myristate 13-acetate, a known agonist of protein kinase C (PKC), suggested a potential role of the PKC signaling pathway in the activation process. The DNA binding activity of endogenous SAF was increased by agonists of PKC. In vitro phosphorylation of SAF-1 by PKC-beta markedly increased its DNA binding ability. Consistent with these findings, treatment of cells with activators of PKC or overexpression of PKC-betaII in transfected cells increased expression of an SAF-regulated promoter. Further analysis with a GAL4 reporter system indicated that PKC-mediated phosphorylation mostly increases the DNA binding activity of SAF-1. Together these data indicated that the PKC signaling pathway plays a major role in controlling expression of SAF-regulated genes by increasing the interaction between promoter DNA and phosphorylated SAF.
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Affiliation(s)
- A Ray
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri 65211, USA
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34
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Uchida S, Tanaka Y, Ito H, Saitoh-Ohara F, Inazawa J, Yokoyama KK, Sasaki S, Marumo F. Transcriptional regulation of the CLC-K1 promoter by myc-associated zinc finger protein and kidney-enriched Krüppel-like factor, a novel zinc finger repressor. Mol Cell Biol 2000; 20:7319-31. [PMID: 10982849 PMCID: PMC86286 DOI: 10.1128/mcb.20.19.7319-7331.2000] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The expression of CLC-K1 and CLC-K2, two kidney-specific CLC chloride channels, is transcriptionally regulated on a tissue-specific basis. Previous studies have shown that a GA element near their transcriptional start sites is important for basal and cell-specific activities of the CLC-K1 and CLC-K2 gene promoters. To identify the GA-binding proteins, the human kidney cDNA library was screened by a yeast one-hybrid system. A novel member of the Cys2-His2 zinc finger gene designated KKLF (for "kidney-enriched Krüppel-like factor") and the previously isolated MAZ (for "myc-associated zinc finger protein") were cloned. KKLF was found to be abundantly expressed in the liver, kidneys, heart, and skeletal muscle, and immunohistochemistry revealed the nuclear localization of KKLF protein in interstitial cells in heart and skeletal muscle, stellate cells, and fibroblasts in the liver. In the kidneys, KKLF protein was localized in interstitial cells, mesangial cells, and nephron segments, where CLC-K1 and CLC-K2 were not expressed. A gel mobility shift assay revealed sequence-specific binding of recombinant KKLF and MAZ proteins to the CLC-K1 GA element, and the fine-mutation assay clarified that the consensus sequence for the KKLF binding site was GGGGNGGNG. In a transient-transfection experiment, MAZ had a strong activating effect on transcription of the CLC-K1-luciferase reporter gene. On the other hand, KKLF coexpression with MAZ appeared to block the activating effect of MAZ. These results suggest that a novel set of zinc finger proteins may help regulate the strict tissue- and nephron segment-specific expression of the CLC-K1 and CLC-K2 channel genes through their GA cis element.
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MESH Headings
- Amino Acid Sequence
- Animals
- Anion Transport Proteins
- Base Sequence
- Carrier Proteins/genetics
- Carrier Proteins/physiology
- Chloride Channels/genetics
- Chloride Channels/metabolism
- Cloning, Molecular
- Collagen/biosynthesis
- Collagen/genetics
- DNA, Complementary/genetics
- DNA-Binding Proteins
- Disease Models, Animal
- Electrophoresis, Polyacrylamide Gel
- Fibroblasts/metabolism
- Gene Expression Regulation
- Genes
- Genes, Reporter
- Humans
- Kruppel-Like Transcription Factors
- Membrane Proteins
- Mice
- Mice, Mutant Strains
- Molecular Sequence Data
- Nephritis, Interstitial/metabolism
- Nephrons/metabolism
- Nuclear Proteins
- Organ Specificity
- Promoter Regions, Genetic
- Protein Binding
- Rats
- Recombinant Fusion Proteins/physiology
- Regulatory Sequences, Nucleic Acid
- Repressor Proteins/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Alignment
- Sequence Homology, Amino Acid
- Transcription Factors/physiology
- Transcription, Genetic
- Transcriptional Activation
- Transfection
- Zinc Fingers/physiology
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Affiliation(s)
- S Uchida
- Second Department of Internal Medicine, School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
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35
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Ray A. A SAF binding site in the promoter region of human gamma-fibrinogen gene functions as an IL-6 response element. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:3411-7. [PMID: 10975860 DOI: 10.4049/jimmunol.165.6.3411] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Expression of fibrinogen is highly induced during inflammation, and such abnormal expression of this protein is considered as a major cardiovascular risk factor. IL-6 is one of the main mediators of abnormal expression of fibrinogen leading to the pathogenic conditions. Transient transfection and EMSA were performed to investigate the molecular mechanism of IL-6-induced gamma-fibrinogen gene expression in hepatic cells. Using progressively deleted 5' fragments of the gamma-fibrinogen promoter coupled to chloramphenicol acetyltransferase gene, an IL-6 responsive element located between positions -273 and -259 was identified. Mutation of this element abrogates IL-6 responsiveness of the gamma-fibrinogen promoter. Interaction of this promoter with a zinc finger transcription factor, serum amyloid A activating factor (SAF)-1, was demonstrated by EMSA. Furthermore, overexpression of wild-type SAF-1 in transfected liver cells can increase transcription of the gamma-fibrinogen promoter. These data show that transcription factor SAF-1 is involved in the regulation of IL-6-mediated induction of the human gamma-fibrinogen gene in liver cells.
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Affiliation(s)
- A Ray
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA.
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36
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Sarafova S, Siu G. Precise arrangement of factor-binding sites is required for murine CD4 promoter function. Nucleic Acids Res 2000; 28:2664-71. [PMID: 10908321 PMCID: PMC102665 DOI: 10.1093/nar/28.14.2664] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The control of CD4 expression is linked to the signaling events that mediate T-cell development and is directly dependent on the CD4 promoter. The CD4 promoter does not contain functionally redundant sites: all four factor-binding sites must be intact to achieve wild-type activity. Here we demonstrate that the precise position of three factor-binding sites relative to each other is essential for promoter activity, indicating that they function together as an inseparable cassette for assembly of the transcription initiation complex. Small changes in either phasing or distance between any two sites in this cassette leads to complete abrogation of promoter function. In addition, we demonstrate that one of the factors that bind the promoter cassette is not present in CD8 SP T(C) cells. Thus, this factor is a candidate for mediating the relative subclass specificity of CD4 promoter function in activated CD4 SP T(H) cells.
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Affiliation(s)
- S Sarafova
- Department of Microbiology and the Integrated Program in Cellular, Molecular and Biophysical Studies, Columbia University, College of Physicians and Surgeons, 701 West 168th Street, New York, NY 10032, USA
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37
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Minagawa M, Kwan MY, Bettoun JD, Mansour FW, Dassa J, Hendy GN, Goltzman D, White JH. Dissection of differentially regulated (G+C)-rich promoters of the human parathyroid hormone (PTH)/PTH-related peptide receptor gene. Endocrinology 2000; 141:2410-21. [PMID: 10875241 DOI: 10.1210/endo.141.7.7559] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The PTH/PTH-related peptide (PTHrP) receptor (PTHR) is required for normal skeletal development, and a wide array of physiological responses mediated by PTH and PTHrP. We have previously identified three promoters, P1-P3, which control human PTHR gene transcription. P2 and P3 are (G+C)-rich, function in a number of tissues, lie within the same CpG island, and display many hallmarks of housekeeping promoters. However, they are differentially regulated during development as P2, but not P3, functions in fetal tissues. Here, we have used both stably and transiently transfected human osteoblast-like cells to delineate regions of P2 and P3 required for promoter activity. Deletion analyses performed in stably transfected cells indicated that sequences extending from -91 to -12 relative to the transcription start site were required for function of the P2 promoter. No negative regulatory elements were detected in P2. In contrast, deletion of an A-rich region of P3 extending from -147 to -115 was required for optimal basal activity, suggesting that this sequence acts as a repressor of P3. Strikingly, however, whereas the A-rich region also functioned as a negative element when inserted upstream of the (G+C)-rich P2 promoter, it enhanced expression from the thymidine kinase promoter, suggesting that its function depends on other transcription factors bound to promoter sequences. Fine deletion of P3 sequences proximal to -115 implicated Spl motifs and downstream initiation sites in P3 function. These studies indicate that function of P2 and P3 is controlled by ubiquitously expressed transcription factors and raise the possibility that P3 activity is repressed during fetal development.
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Affiliation(s)
- M Minagawa
- Department of Medicine, McGill University, Montréal, Québec, Canada
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38
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Stubbs MC, Min I, Izzo MW, Rallapalli R, Derfoul A, Hall DJ. The ZF87/MAZ transcription factor functions as a growth suppressor in fibroblasts. Biochem Cell Biol 2000. [DOI: 10.1139/o00-053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
ZF87/MAZ is a zinc finger transcription factor that activates expression of tissue-specific genes and represses expression of the c-myc proto-oncogene. Infection of NIH3T3 fibroblasts with a retrovirus expressing ZF87/MAZ leads to a significant reduction in G418-resistant colonies, compared to cells infected with a retroviral control. Further, only a small fraction of the G418-resistant colonies express ZF87/MAZ. When the ZF87/MAZ-expressing colonies are expanded, they demonstrate a slow growth phenotype, a delayed transit through G1 phase and a decrease in endogenous c-myc gene expression and cyclin A and cyclin E protein levels. Consistent with a partial G1 arrest, the ZF87/MAZ-expressing cells show a reduced sensitivity to the S phase specific chemotherapeutic agent camptothecin. These data indicate that ZF87/MAZ is a growth suppressor protein in nontransformed cells, in part, by affecting the levels of key cell cycle regulatory proteins.Key words: cell cycle, ZF87/MAZ, cancer.
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39
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Brabletz T, Jung A, Hlubek F, Löhberg C, Meiler J, Suchy U, Kirchner T. Negative regulation of CD4 expression in T cells by the transcriptional repressor ZEB. Int Immunol 1999; 11:1701-8. [PMID: 10508188 DOI: 10.1093/intimm/11.10.1701] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
ZEB, an E-box binding transcriptional repressor, is an important regulator of T cell and muscle development. Targeted disruption of ZEB in mice resulted in a strong reduction of thymocytes and the few T cells that reached the mature stage were predominantly CD4(+). CD4 expression during the various stages of T cell differentiation is controlled at the transcriptional level by a complex array of regulatory elements in the CD4 gene locus, consisting of at least three enhancers, one promoter and one silencer. Here we present evidence that CD4 gene expression is negatively regulated by ZEB. We show that ZEB binds to the 5'E-box in the CD4-3 element of the proximal CD4 enhancer in competition with the transcriptional activators E12 and HEB, thereby reducing CD4 expression on CD4 single-positive but not CD4/CD8 double-positive T cells. The conversion of the CD4 proximal enhancer into a potential silencer element by the transcriptional repressor ZEB offers an additional concept of CD4 gene regulation in T cells.
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Affiliation(s)
- T Brabletz
- Department of Pathology, University of Erlangen-Nürnberg, Krankenhausstrasse 8-10, 91054 Erlangen, Germany
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40
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Tsutsui H, Geltinger C, Murata T, Itakura K, Wada T, Handa H, Yokoyama KK. The DNA-binding and transcriptional activities of MAZ, a myc-associated zinc finger protein, are regulated by casein kinase II. Biochem Biophys Res Commun 1999; 262:198-205. [PMID: 10448092 DOI: 10.1006/bbrc.1999.1130] [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: 11/22/2022]
Abstract
Myc-associated zinc finger protein (MAZ) is a transcription factor that contains proline-rich, alanine repeats and six C(2)H(2)-type zinc finger motifs, as well as five putative sites of phosphorylation by casein kinase II (CKII). Site-specific mutagenesis of MAZ revealed that the serine residue at position 480 was the major site of phosphorylation by CKII both in vitro and in vivo. Phosphorylation of MAZ by CKII at this serine residue was required for maximum binding of MAZ to the pyrimidine-rich DNA of the nuclease-hypersensitive element (NHE) in the 5'-end promoter region of the c-myc gene. Mutation of serine at position 480 to alanine eliminated the DNA-binding activity of MAZ to this element. Moreover, the mutated MAZ was unable to enhance the expression of luciferase encoded by a c-myc promoter/luciferase reporter gene in HeLa cells in the presence of CKII. These results suggest that phosphorylation of the serine residue at position 480 of MAZ by CKII can control the function of MAZ by altering its DNA-binding activity.
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Affiliation(s)
- H Tsutsui
- Tsukuba Life Science Center, RIKEN (The Institute of Physical and Chemical Research), 3-1-1 Koyadai, Tsukuba, Ibaraki, 305-0074, Japan
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41
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Kim WW, Siu G. Subclass-specific nuclear localization of a novel CD4 silencer binding factor. J Exp Med 1999; 190:281-91. [PMID: 10432290 PMCID: PMC2195567 DOI: 10.1084/jem.190.2.281] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/1999] [Accepted: 06/02/1999] [Indexed: 01/25/2023] Open
Abstract
The control of CD4 expression is essential for proper T lymphocyte development. We have previously described a cis-acting silencer element required for repressing transcription of the CD4 gene. Here we report the cloning and characterization of a novel factor that binds to a critical functional site in the CD4 silencer. This factor, referred to as silencer-associated factor (SAF), is a member of the helix-turn-helix factor family and shares sequence similarity with the homeodomain class of transcriptional regulators. Introduction of a specific mutation into the SAF binding site in the CD4 silencer abrogates silencer activity in transgenic mice, supporting the hypothesis that SAF is important in mediating silencer function. Although SAF is expressed in all lymphocytes, immunofluorescence studies indicate that SAF is present primarily in the cytoplasm in T cells in which the endogenous silencer is nonfunctional, whereas it is present primarily in the nucleus in T cells in which the silencer is functional. We thus hypothesize that the subclass-specific subcellular compartmentalization of SAF plays an important role in mediating the specificity of function of the CD4 silencer during T cell development.
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Affiliation(s)
- William W.S. Kim
- From the Department of Microbiology and the Integrated Program in Cellular, Molecular and Biophysical Studies, Columbia University College of Physicians and Surgeons, New York 10032
| | - Gerald Siu
- From the Department of Microbiology and the Integrated Program in Cellular, Molecular and Biophysical Studies, Columbia University College of Physicians and Surgeons, New York 10032
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42
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Izzo MW, Strachan GD, Stubbs MC, Hall DJ. Transcriptional repression from the c-myc P2 promoter by the zinc finger protein ZF87/MAZ. J Biol Chem 1999; 274:19498-506. [PMID: 10383467 DOI: 10.1074/jbc.274.27.19498] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ZF87/MAZ is a zinc finger-containing transcription factor that was cloned based on its ability to bind to a site within the c-myc P2 promoter. However, its role in the control of c-myc transcription has not yet been well established. Here we have analyzed the effect of ZF87/MAZ overexpression on transcription from the murine c-myc P2 promoter. It was found that when overexpressed in COS cells, ZF87/MAZ significantly represses transcription from P2. The repression is mediated through the ME1a2 element, located at position -86 relative to the P2 transcriptional start site, and is not mediated through either the E2F or the ME1a1 sites. ZF87/MAZ functions as a true transcriptional repressor since it can repress transcription independently of the c-myc promoter, as part of a fusion with the GAL4 protein. The repressive domain within ZF87/MAZ is located in the amino-terminal half of the protein, a region rich in proline and alanine residues. ZF87/MAZ therefore shares features (i.e. a Pro/Ala-rich region) with those of known transcriptional repressor proteins.
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Affiliation(s)
- M W Izzo
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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43
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Sarafova SD, Siu G. Control of CD4 gene expression: connecting signals to outcomes in T cell development. Braz J Med Biol Res 1999; 32:785-803. [PMID: 10454736 DOI: 10.1590/s0100-879x1999000700001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The control of CD4 gene expression is essential for proper T lymphocyte development. Signals transmitted from the T-cell antigen receptor (TCR) during the thymic selection processes are believed to be linked to the regulation of CD4 gene expression during specific stages of T cell development. Thus, a study of the factors that control CD4 gene expression may lead to further insight into the molecular mechanisms that drive thymic selection. In this review, we discuss the work conducted to date to identify and characterize the cis-acting transcriptional control elements in the CD4 locus and the DNA-binding factors that mediate their function. From these studies, it is becoming clear that the molecular mechanisms controlling CD4 gene expression are very complex and differ at each stage of development. Thus, the control of CD4 expression is subject to many different influences as the thymocyte develops.
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Affiliation(s)
- S D Sarafova
- Department of Microbiology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
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44
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Ellmeier W, Sawada S, Littman DR. The regulation of CD4 and CD8 coreceptor gene expression during T cell development. Annu Rev Immunol 1999; 17:523-54. [PMID: 10358767 DOI: 10.1146/annurev.immunol.17.1.523] [Citation(s) in RCA: 208] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The two major subsets of T lymphocytes in the peripheral immune system, the helper and cytotoxic T cells, are defined by their expression of either the CD4 or the CD8 glycoproteins, respectively. Expression of these molecules, which serve as coreceptors by interacting specifically with either MHC class II or class I molecules, also defines discrete stages of T cell development within the thymus. Thus, CD4+ and CD8+ single-positive (SP) thymocytes arise from common progenitor double positive (DP) cells that express both CD4 and CD8, during a process known as positive selection. The molecular mechanisms underlying the developmental choice toward the helper or cytotoxic lineage remain poorly understood. Because regulation of coreceptor gene expression appears to be coupled to the phenotypic choice of the differentiating T cell, it is likely that shared signaling pathways direct CD4 and CD8 transcription and the development of an uncommited DP thymocyte toward either the helper or cytotoxic lineage. Therefore, an understanding of how CD4 and CD8 expression is regulated will not only provide insights into transcriptional control mechanisms in T cells, but may also result in the identification of molecular factors that are involved in lineage choices during T cell development. In this review, we summarize recent progress that has been made toward an understanding of how CD4 and CD8 gene expression is regulated.
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Affiliation(s)
- W Ellmeier
- Molecular Pathogenesis Program, Skirball Institute of Biomolecular Medicine, New York, NY 10016, USA
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45
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Abstract
The control of CD4 gene expression is believed to be linked directly to the signaling events that mediate T cell development and is directly dependent on the CD4 promoter. We have previously determined that this promoter contains four factor-binding sites important for its function. One of these sites, referred to as the P4 site, contains an Ets consensus recognition sequence. Using functional and biochemical analyses, we determine that Elf-1 binds to this site and specifically activates the CD4 promoter, indicating that Elf-1 is playing an important role in CD4 promoter function. In addition, a second nuclear factor binds to this region. Although there are consensus recognition sites for other factors, we demonstrate that none of these factors binds to the P4 site, nor do other known members of the Ets family. Thus, a novel transcription factor may bind to the CD4 promoter and help mediate its function.
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Affiliation(s)
- S Sarafova
- Integrated Program in Cellular, Molecular, and Biophysical Studies, Columbia University, College of Physicians and Surgeons, New York, New York 10032, USA
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46
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Her S, Bell RA, Bloom AK, Siddall BJ, Wong DL. Phenylethanolamine N-methyltransferase gene expression. Sp1 and MAZ potential for tissue-specific expression. J Biol Chem 1999; 274:8698-707. [PMID: 10085109 DOI: 10.1074/jbc.274.13.8698] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Phenylethanolamine N-methyltransferase (PNMT) promoter-luciferase reporter gene constructs (pGL3RP863, pGL3RP444, and pGL3RP392) transfected into COS1, RS1, PC12, NIH/3T3, or Neuro2A cells showed the highest basal luciferase activity in the Neuro2A cells. DNase I footprinting with Neuro2A cell nuclear extract identified protected PNMT promoter regions spanning the -168/-165 and -48/-45 base pair Sp1/Egr-1 binding sites. Gel mobility shift assays and transient transfection assays using site-directed mutant PNMT promoter-luciferase reporter gene constructs indicated that the elevated basal luciferase activity in the Neuro2A cells was mediated by Sp-1. Furthermore, activation of the PNMT promoter by Sp1 depends on both its binding affinity for its cognate target sequences and its intracellular concentrations. When Sp1 levels were increased through an expression plasmid, luciferase reporter gene expression rose well beyond basal wild-type levels, even with either Sp1 binding element mutated. Finally, another transcription factor expressed in the Neuro2A cells competes with Sp1 by interacting with DNA sequences 3' to the -48 base pair Sp1 site to prevent Sp1 binding and induction of the PNMT promoter. The DNA consensus sequence, Southwestern analysis, and gel mobility shift assays with antibodies identify MAZ as the competitive factor. These findings suggest that Sp1 may potentially contribute to the tissue-specific expression of the PNMT gene, with the competition between Sp1 and MAZ conferring additional tissue-specific control.
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Affiliation(s)
- S Her
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California 94305-5485, USA
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47
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Xiong JW, Leahy A, Lee HH, Stuhlmann H. Vezf1: A Zn finger transcription factor restricted to endothelial cells and their precursors. Dev Biol 1999; 206:123-41. [PMID: 9986727 DOI: 10.1006/dbio.1998.9144] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Using retroviral entrapment vectors, we identified a novel mouse gene whose expression is restricted to vascular endothelial cells and their precursors in the yolk sac blood islands. A 3.68-kb cDNA corresponding to the endogenous transcript was isolated using genomic DNA flanking the entrapment vector insertion as a probe. We have named this gene Vezf1 for vascular endothelial zinc finger 1. Vezf1 encodes a protein with a predicted molecular mass of 56 kDa and that contains six putative zinc finger domains and shows high homology to a previously identified human gene, DB1, that is believed to be involved in regulating expression of cytokine genes such as interleukin-3. In situ hybridization analysis revealed the onset of expression in advanced primitive streak-stage embryos being located in the extraembryonic mesodermal component of the visceral yolk sac and in the anteriormost mesoderm of the embryo proper. During head-fold and somite stages, expression was restricted to vascular endothelial cells that arise during both vasculogenesis and angiogenesis. Vezf1-related sequences were found to be highly conserved among higher vertebrate species that have acquired extraembryonic yolk sac membranes during evolution. The Vezf1 locus mapped to the proximal part of mouse chromosome 2, a region which has homology to human chromosome 9q. Vezf1 expression correlates temporally and spatially with the early differentiation of angioblasts into the endothelial cell lineage and the proliferation of endothelial cells of the embryonic vascular system. Thus, Vezf1 may play an important role in the endothelial lineage determination and may have an additional role during later stages of embryonic vasculogenesis and angiogenesis.
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Affiliation(s)
- J W Xiong
- Brookdale Center for Developmental and Molecular Biology, Mount Sinai School of Medicine, New York, New York, 10029, USA
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48
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Song J, Murakami H, Tsutsui H, Ugai H, Geltinger C, Murata T, Matsumura M, Itakura K, Kanazawa I, Sun K, Yokoyama KK. Structural organization and expression of the mouse gene for Pur-1, a highly conserved homolog of the human MAZ gene. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 259:676-83. [PMID: 10092852 DOI: 10.1046/j.1432-1327.1999.00081.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have characterized the genomic structure and expression of the mouse gene for Pur-1. The cloned Pur-1 gene spans a 5-kb region encompassing the promoter, five exons, four introns and the 3'-untranslated region. All exon-intron junction sequences conform to the GT/AG rule. The promoter region has typical features of a housekeeping gene: a high G + C content (77.5%); a high frequency of CpG dinucleotides, in particular within the region 0.5 kb upstream of the site of initiation of translation; and the absence of canonical TATA and CAAT boxes. S1 nuclease protection assay demonstrated the presence of multiple sites for initiation of transcription around a site 108 nucleotides upstream of the ATG codon. Comparison of Pur-1 with the human gene for MAZ (Myc-associated zinc finger protein) revealed a striking homology of both their nucleotide and deduced protein sequences, an identical genomic organization and high similarity in promoter architecture and mRNA expression pattern. Sequence analysis of the 5'-flanking region of Pur-1 revealed numerous potential binding sites for transcription factors Sp1, AP-2 and Pur-1/MAZ itself. An element required for basal Pur-1 expression was mapped from nucleotide -258 to +43. This region also mediated stimulation of basal transcription by ectopically expressed MAZ protein. We conclude that the Pur-1 gene is the murine homolog of human MAZ and, like it, belongs to the family of housekeeping genes.
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Affiliation(s)
- J Song
- Tsukuba Life Science Center, Ibaraki, Japan
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Karantzoulis-Fegaras F, Antoniou H, Lai SL, Kulkarni G, D'Abreo C, Wong GK, Miller TL, Chan Y, Atkins J, Wang Y, Marsden PA. Characterization of the human endothelial nitric-oxide synthase promoter. J Biol Chem 1999; 274:3076-93. [PMID: 9915847 DOI: 10.1074/jbc.274.5.3076] [Citation(s) in RCA: 160] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Understanding transcription initiation of the endothelial nitric-oxide synthase (eNOS) gene appears pivotal to gaining a comprehensive view of NO biology in the blood vessel wall. The present study therefore focused upon a detailed dissection of the functionally important cis-DNA elements and the multiprotein complexes implicated in the cooperative control of constitutive expression of the human eNOS gene in vascular endothelium. Two tightly clustered cis-regulatory regions were identified in the proximal enhancer of the TATA-less eNOS promoter using deletion analysis and linker-scanning mutagenesis: positive regulatory domains I (-104/-95 relative to transcription initiation) and II (-144/-115). Analysis of trans-factor binding and functional expression studies revealed a surprising degree of cooperativity and complexity. The nucleoprotein complexes that form upon these regions in endothelial cells contained Ets family members, Sp1, variants of Sp3, MAZ, and YY1. Functional domain studies in Drosophila Schneider cells and endothelial cells revealed examples of positive and negative protein-protein cooperativity involving Sp1, variants of Sp3, Ets-1, Elf-1, and MAZ. Therefore, multiprotein complexes are formed on the activator recognition sites within this 50-base pair region of the human eNOS promoter in vascular endothelium.
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Affiliation(s)
- F Karantzoulis-Fegaras
- Renal Division and Department of Medicine, St. Michael's Hospital and University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Kim HK, Siu G. The notch pathway intermediate HES-1 silences CD4 gene expression. Mol Cell Biol 1998; 18:7166-75. [PMID: 9819403 PMCID: PMC109298 DOI: 10.1128/mcb.18.12.7166] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/1998] [Accepted: 09/10/1998] [Indexed: 11/20/2022] Open
Abstract
We have previously identified a transcriptional silencer that is critical for proper expression of the CD4 gene during T-cell development. Here we report that the Hairy/Enhancer of Split homologue HES-1, a transcription factor in the lin12/Notch signaling pathway, binds to an important functional site in the CD4 silencer. Overexpression of HES-1 leads to the silencer site-dependent repression of CD4 promoter and enhancer function as well as the downregulation of endogenous CD4 expression in CD4(+) CD8(-) TH cells. Interestingly, overexpression of an activated form of Notch1 (NotchIC) leads to the repression of CD4 promoter and enhancer function both in the presence and absence of the silencer. NotchIC-mediated CD4 silencer function is not affected by the deletion of the HES-1-binding site, indicating that multiple factors binding to CD4 transcriptional control elements are responsive to signaling from this pathway, including other silencer-binding factors. Taken together, these data are consistent with the hypothesis that the lin12/Notch signaling pathway is important in thymic development and provide a molecular mechanism via the control of CD4 gene expression in which the lin12/Notch pathway affects T-cell developmental fate.
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Affiliation(s)
- H K Kim
- Department of Microbiology, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA
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