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Hong Y, Bie L, Zhang T, Yan X, Jin G, Chen Z, Wang Y, Li X, Pei G, Zhang Y, Hong Y, Gong L, Li P, Xie W, Zhu Y, Shen X, Liu N. SAFB restricts contact domain boundaries associated with L1 chimeric transcription. Mol Cell 2024; 84:1637-1650.e10. [PMID: 38604171 DOI: 10.1016/j.molcel.2024.03.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 02/05/2024] [Accepted: 03/19/2024] [Indexed: 04/13/2024]
Abstract
Long interspersed element-1 (LINE-1 or L1) comprises 17% of the human genome, continuously generates genetic variations, and causes disease in certain cases. However, the regulation and function of L1 remain poorly understood. Here, we uncover that L1 can enrich RNA polymerase IIs (RNA Pol IIs), express L1 chimeric transcripts, and create contact domain boundaries in human cells. This impact of L1 is restricted by a nuclear matrix protein scaffold attachment factor B (SAFB) that recognizes transcriptionally active L1s by binding L1 transcripts to inhibit RNA Pol II enrichment. Acute inhibition of RNA Pol II transcription abolishes the domain boundaries associated with L1 chimeric transcripts, indicating a transcription-dependent mechanism. Deleting L1 impairs domain boundary formation, and L1 insertions during evolution have introduced species-specific domain boundaries. Our data show that L1 can create RNA Pol II-enriched regions that alter genome organization and that SAFB regulates L1 and RNA Pol II activity to preserve gene regulation.
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Affiliation(s)
- Yaqiang Hong
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Luyao Bie
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Tao Zhang
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaohan Yan
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Guangpu Jin
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Zhuo Chen
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yang Wang
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiufeng Li
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Gaofeng Pei
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yongyan Zhang
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yantao Hong
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Liang Gong
- Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou 311121, China
| | - Pilong Li
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wei Xie
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yanfen Zhu
- International Institutes of Medicine, The Fourth Affiliated Hospital of Zhejiang University School of Medicine, Yiwu 322000, China
| | - Xiaohua Shen
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Nian Liu
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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2
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Cherney RE, Eberhard QE, Giri G, Mills CA, Porrello A, Zhang Z, White D, Trotman JB, Herring LE, Dominguez D, Calabrese JM. SAFB associates with nascent RNAs and can promote gene expression in mouse embryonic stem cells. RNA (NEW YORK, N.Y.) 2023; 29:1535-1556. [PMID: 37468167 PMCID: PMC10578485 DOI: 10.1261/rna.079569.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 06/23/2023] [Indexed: 07/21/2023]
Abstract
Scaffold attachment factor B (SAFB) is a conserved RNA-binding protein that is essential for early mammalian development. However, the functions of SAFB in mouse embryonic stem cells (ESCs) have not been characterized. Using RNA immunoprecipitation followed by RNA-seq (RIP-seq), we examined the RNAs associated with SAFB in wild-type and SAFB/SAFB2 double-knockout ESCs. SAFB predominantly associated with introns of protein-coding genes through purine-rich motifs. The transcript most enriched in SAFB association was the lncRNA Malat1, which also contains a purine-rich region in its 5' end. Knockout of SAFB/SAFB2 led to differential expression of approximately 1000 genes associated with multiple biological processes, including apoptosis, cell division, and cell migration. Knockout of SAFB/SAFB2 also led to splicing changes in a set of genes that were largely distinct from those that exhibited changes in expression level. The spliced and nascent transcripts of many genes whose expression levels were positively regulated by SAFB also associated with high levels of SAFB, implying that SAFB binding promotes their expression. Reintroduction of SAFB into double-knockout cells restored gene expression toward wild-type levels, an effect again observable at the level of spliced and nascent transcripts. Proteomics analysis revealed a significant enrichment of nuclear speckle-associated and RS domain-containing proteins among SAFB interactors. Neither Xist nor Polycomb functions were dramatically altered in SAFB/2 knockout ESCs. Our findings suggest that among other potential functions in ESCs, SAFB promotes the expression of certain genes through its ability to bind nascent RNA.
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Affiliation(s)
- Rachel E Cherney
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- RNA Discovery Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Quinn E Eberhard
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- RNA Discovery Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Gilbert Giri
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- RNA Discovery Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Christine A Mills
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Proteomics Core Facility, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Alessandro Porrello
- RNA Discovery Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Zhiyue Zhang
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - David White
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Jackson B Trotman
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- RNA Discovery Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Laura E Herring
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Proteomics Core Facility, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Daniel Dominguez
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- RNA Discovery Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - J Mauro Calabrese
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- RNA Discovery Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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3
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Agrawal-Singh S, Bagri J, Giotopoulos G, Azazi DMA, Horton SJ, Lopez CK, Anand S, Bach AS, Stedham F, Antrobus R, Houghton JW, Vassiliou GS, Sasca D, Yun H, Whetton AD, Huntly BJP. HOXA9 forms a repressive complex with nuclear matrix-associated protein SAFB to maintain acute myeloid leukemia. Blood 2023; 141:1737-1754. [PMID: 36577137 PMCID: PMC10113176 DOI: 10.1182/blood.2022016528] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 11/07/2022] [Accepted: 11/28/2022] [Indexed: 12/29/2022] Open
Abstract
HOXA9 is commonly upregulated in acute myeloid leukemia (AML), in which it confers a poor prognosis. Characterizing the protein interactome of endogenous HOXA9 in human AML, we identified a chromatin complex of HOXA9 with the nuclear matrix attachment protein SAFB. SAFB perturbation phenocopied HOXA9 knockout to decrease AML proliferation, increase differentiation and apoptosis in vitro, and prolong survival in vivo. Integrated genomic, transcriptomic, and proteomic analyses further demonstrated that the HOXA9-SAFB (H9SB)-chromatin complex associates with nucleosome remodeling and histone deacetylase (NuRD) and HP1γ to repress the expression of factors associated with differentiation and apoptosis, including NOTCH1, CEBPδ, S100A8, and CDKN1A. Chemical or genetic perturbation of NuRD and HP1γ-associated catalytic activity also triggered differentiation, apoptosis, and the induction of these tumor-suppressive genes. Importantly, this mechanism is operative in other HOXA9-dependent AML genotypes. This mechanistic insight demonstrates the active HOXA9-dependent differentiation block as a potent mechanism of disease maintenance in AML that may be amenable to therapeutic intervention by targeting the H9SB interface and/or NuRD and HP1γ activity.
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Affiliation(s)
- Shuchi Agrawal-Singh
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge, United Kingdom
- Department of Haematology, University of Cambridge, Cambridge, United Kingdom
| | - Jaana Bagri
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge, United Kingdom
- Department of Haematology, University of Cambridge, Cambridge, United Kingdom
| | - George Giotopoulos
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge, United Kingdom
- Department of Haematology, University of Cambridge, Cambridge, United Kingdom
| | - Dhoyazan M A Azazi
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge, United Kingdom
- Department of Haematology, University of Cambridge, Cambridge, United Kingdom
| | - Sarah J Horton
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge, United Kingdom
- Department of Haematology, University of Cambridge, Cambridge, United Kingdom
| | - Cecile K Lopez
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge, United Kingdom
- Department of Haematology, University of Cambridge, Cambridge, United Kingdom
| | - Shubha Anand
- Cancer Molecular Diagnostics Laboratory, Cancer Research UK Cambridge Centre, Cambridge, United Kingdom
| | - Anne-Sophie Bach
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge, United Kingdom
- Department of Haematology, University of Cambridge, Cambridge, United Kingdom
| | - Frances Stedham
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge, United Kingdom
- Department of Haematology, University of Cambridge, Cambridge, United Kingdom
| | - Robin Antrobus
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Jack W Houghton
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - George S Vassiliou
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge, United Kingdom
- Department of Haematology, University of Cambridge, Cambridge, United Kingdom
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom
| | - Daniel Sasca
- Department of Hematology, Oncology and Pneumology, University Medical Center Mainz, Mainz, Germany
| | - Haiyang Yun
- Department of Medicine V, Hematology, Oncology and Rheumatology, University of Heidelberg, Heidelberg, Germany
| | - Anthony D Whetton
- School of Veterinary Medicine, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, United Kingdom
| | - Brian J P Huntly
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge, United Kingdom
- Department of Haematology, University of Cambridge, Cambridge, United Kingdom
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
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4
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Pu Y, Han J, Zhang M, Liu M, Abdusamat G, Liu H. SKA1 promotes tumor metastasis via SAFB-mediated transcription repression of DUSP6 in clear cell renal cell carcinoma. Aging (Albany NY) 2022; 14:9679-9698. [PMID: 36462498 PMCID: PMC9792197 DOI: 10.18632/aging.204418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 11/19/2022] [Indexed: 12/03/2022]
Abstract
The most hostile form of urologic cancer, clear cell renal cell carcinoma (ccRCC), has a high fatality rate and poor prognosis due to tumor metastasis at initial presentation. The complex process driving ccRCC metastasis is still unknown, though. In this study, we demonstrate that Spindle and kinetochore-associated protein 1 (SKA1) expression is significantly upregulated in ccRCC tissues and associated with aggressive clinicopathologic characteristics. Functionally, SKA1 knockdown on ccRCC cells reduced cancer cell motility both in vivo and in vitro research. These bioactivities of SKA1 may be brought on by its specific interaction with scaffold attachment factor B, according to the proposed mechanism (SAFB), which could further depress the transcription of dual specificity phosphatase 6 (DUSP6). Our findings may provide a new way of researching SKA1-regulated tumor metastasis, and indicate that SKA1 is a prospective therapeutic target for renal carcinoma.
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Affiliation(s)
- Yan Pu
- Institute of Cancer Research, Affiliated Tumor Hospital of Xinjiang Medical University, Urumqi 830011, PR China
| | - Jing Han
- Institute of Cancer Research, Affiliated Tumor Hospital of Xinjiang Medical University, Urumqi 830011, PR China
| | - Mengmeng Zhang
- Institute of Cancer Research, Affiliated Tumor Hospital of Xinjiang Medical University, Urumqi 830011, PR China
| | - Mengxue Liu
- Institute of Cancer Research, Affiliated Tumor Hospital of Xinjiang Medical University, Urumqi 830011, PR China
| | - Gulnazar Abdusamat
- Department of Pharmacy, Xinjiang Medical University, Urumqi 830011, PR China
| | - Huibin Liu
- Institute of Cancer Research, Affiliated Tumor Hospital of Xinjiang Medical University, Urumqi 830011, PR China,The Clinical Research Center of Breast Tumor and Thyroid Tumor in Xinjiang Autonomous Region, Urumqi 830011, PR China
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5
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Taze C, Drakouli S, Samiotaki M, Panayotou G, Simos G, Georgatsou E, Mylonis I. Short-term hypoxia triggers ROS and SAFB mediated nuclear matrix and mRNA splicing remodeling. Redox Biol 2022; 58:102545. [PMID: 36427398 PMCID: PMC9692040 DOI: 10.1016/j.redox.2022.102545] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 11/16/2022] [Indexed: 11/18/2022] Open
Abstract
The cellular response to hypoxia, in addition to HIF-dependent transcriptional reprogramming, also involves less characterized transcription-independent processes, such as alternative splicing of the VEGFA transcript leading to the production of the proangiogenic VEGF form. We now show that this event depends on reorganization of the splicing machinery, triggered after short-term hypoxia by ROS production and intranuclear redistribution of the nucleoskeletal proteins SAFB1/2. Exposure to low oxygen causes fast dissociation of SAFB1/2 from the nuclear matrix, which is reversible, inhibited by antioxidant treatment, and also observed under normoxia when the mitochondrial electron transport chain is blocked. This is accompanied by altered interactions between SAFB1/2 and the splicing machinery, translocation of kinase SRPK1 to the cytoplasm, and dephosphorylation of RS-splicing factors. Depletion of SAFB1/2 under normoxia phenocopies the hypoxic and ROS-mediated switch in VEGF mRNA splicing. These data suggest that ROS-dependent remodeling of the nuclear architecture can promote production of splicing variants that facilitate adaptation to hypoxia.
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Affiliation(s)
- Chrysa Taze
- Laboratory of Biochemistry, Faculty of Medicine, University of Thessaly, Biopolis, Larissa, 41500, Greece
| | - Sotiria Drakouli
- Laboratory of Biochemistry, Faculty of Medicine, University of Thessaly, Biopolis, Larissa, 41500, Greece
| | - Martina Samiotaki
- Institute for Bioinnovation, BSRC “Alexander Fleming”, Vari, 16672, Greece
| | - George Panayotou
- Institute for Bioinnovation, BSRC “Alexander Fleming”, Vari, 16672, Greece
| | - George Simos
- Laboratory of Biochemistry, Faculty of Medicine, University of Thessaly, Biopolis, Larissa, 41500, Greece,Gerald Bronfman Department of Oncology, Faculty of Medicine, McGill University, Montreal, H4A 3T2, Canada
| | - Eleni Georgatsou
- Laboratory of Biochemistry, Faculty of Medicine, University of Thessaly, Biopolis, Larissa, 41500, Greece
| | - Ilias Mylonis
- Laboratory of Biochemistry, Faculty of Medicine, University of Thessaly, Biopolis, Larissa, 41500, Greece,Corresponding author.
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6
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Inhibition of HSF1 and SAFB Granule Formation Enhances Apoptosis Induced by Heat Stress. Int J Mol Sci 2021; 22:ijms22094982. [PMID: 34067147 PMCID: PMC8124827 DOI: 10.3390/ijms22094982] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/13/2021] [Accepted: 05/05/2021] [Indexed: 12/12/2022] Open
Abstract
Stress resistance mechanisms include upregulation of heat shock proteins (HSPs) and formation of granules. Stress-induced granules are classified into stress granules and nuclear stress bodies (nSBs). The present study examined the involvement of nSB formation in thermal resistance. We used chemical compounds that inhibit heat shock transcription factor 1 (HSF1) and scaffold attachment factor B (SAFB) granule formation and determined their effect on granule formation and HSP expression in HeLa cells. We found that formation of HSF1 and SAFB granules was inhibited by 2,5-hexanediol. We also found that suppression of HSF1 and SAFB granule formation enhanced heat stress-induced apoptosis. In addition, the upregulation of HSP27 and HSP70 during heat stress recovery was suppressed by 2,5-hexanediol. Our results suggested that the formation of HSF1 and SAFB granules was likely to be involved in the upregulation of HSP27 and HSP70 during heat stress recovery. Thus, the formation of HSF1 and SAFB granules was involved in thermal resistance.
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7
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Luo S, Zhang M, Wu H, Ding X, Li D, Dong X, Hu X, Su S, Shang W, Wu J, Xiao H, Yang W, Zhang Q, Zhang J, Lu Y, Pan Z. SAIL: a new conserved anti-fibrotic lncRNA in the heart. Basic Res Cardiol 2021; 116:15. [PMID: 33675440 DOI: 10.1007/s00395-021-00854-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 02/12/2021] [Indexed: 12/19/2022]
Abstract
Long non-coding RNAs (lncRNAs) account for a large proportion of genomic transcripts and are critical regulators in various cardiac diseases. Though lncRNAs have been reported to participate in the process of diverse cardiac diseases, the contribution of lncRNAs in cardiac fibrosis remains to be fully elucidated. Here, we identified a novel anti-fibrotic lncRNA, SAIL (scaffold attachment factor B interacting lncRNA). SAIL was reduced in cardiac fibrotic tissue and activated cardiac fibroblasts. Gain- and loss-of-function studies showed that knockdown of SAIL promoted proliferation and collagen production of cardiac fibroblasts with or without TGF-β1 (transforming growth factor beta1) treatment, while overexpression of SAIL did the opposite. In mouse cardiac fibrosis induced by myocardial infarction, knockdown of SAIL exacerbated, whereas overexpression of SAIL alleviated cardiac fibrosis. Mechanically, SAIL inhibited the fibrotic process by directly binding with SAFB via 23 conserved nucleotide sequences, which in turn blocked the access of SAFB to RNA pol II (RNA polymerase II) and reduced the transcription of fibrosis-related genes. Intriguingly, the human conserved fragment of SAIL (hSAIL) significantly suppressed the proliferation and collagen production of human cardiac fibroblasts. Our findings demonstrate that SAIL regulates cardiac fibrosis by regulating SAFB-mediated transcription of fibrotic related genes. Both SAIL and SAFB hold the potential to become novel therapeutic targets for cardiac fibrosis.
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Affiliation(s)
- Shenjian Luo
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
- Translational Medicine Research and Cooperation Center of Northern China, Heilongjiang Academy of Medical Sciences, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
| | - Mingyu Zhang
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
| | - Hao Wu
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
- Translational Medicine Research and Cooperation Center of Northern China, Heilongjiang Academy of Medical Sciences, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
| | - Xin Ding
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
- Translational Medicine Research and Cooperation Center of Northern China, Heilongjiang Academy of Medical Sciences, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
| | - Danyang Li
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
- Translational Medicine Research and Cooperation Center of Northern China, Heilongjiang Academy of Medical Sciences, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
| | - Xue Dong
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
| | - Xiaoxi Hu
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
| | - Shuang Su
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
| | - Wendi Shang
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
| | - Jiaxu Wu
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
| | - Hongwen Xiao
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
| | - Wanqi Yang
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
| | - Qi Zhang
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
| | - Jifan Zhang
- Translational Medicine Research and Cooperation Center of Northern China, Heilongjiang Academy of Medical Sciences, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
| | - Yanjie Lu
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
- Translational Medicine Research and Cooperation Center of Northern China, Heilongjiang Academy of Medical Sciences, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China
| | - Zhenwei Pan
- Department of Pharmacology, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150081, Heilongjiang, People's Republic of China.
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8
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Buckner N, Kemp KC, Scott HL, Shi G, Rivers C, Gialeli A, Wong LF, Cordero-LLana O, Allen N, Wilkins A, Uney JB. Abnormal scaffold attachment factor 1 expression and localization in spinocerebellar ataxias and Huntington's chorea. Brain Pathol 2020; 30:1041-1055. [PMID: 32580238 PMCID: PMC8018166 DOI: 10.1111/bpa.12872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
SAFB1 is a DNA and RNA binding protein that is highly expressed in the cerebellum and hippocampus and is involved in the processing of coding and non-coding RNAs, splicing and dendritic function. We analyzed SAFB1 expression in the post-mortem brain tissue of spinocerebellar ataxia (SCA), Huntington's disease (HD), Multiple sclerosis (MS), Parkinson's disease patients and controls. In SCA cases, the expression of SAFB1 in the nucleus was increased and there was abnormal and extensive expression in the cytoplasm where it co-localized with the markers of Purkinje cell injury. Significantly, no SAFB1 expression was found in the cerebellar neurons of the dentate nucleus in control or MS patients; however, in SCA patients, SAFB1 expression was increased significantly in both the nucleus and cytoplasm of dentate neurons. In HD, we found that SAFB1 expression was increased in the nucleus and cytoplasm of striatal neurons; however, there was no SAFB1 staining in the striatal neurons of controls. In PD substantia nigra, we did not see any changes in neuronal SAFB1 expression. iCLIP analysis found that SAFB1 crosslink sites within ATXN1 RNA were adjacent to the start and within the glutamine repeat sequence. Further investigation found increased binding of SAFB1 to pathogenic ATXN1-85Q mRNA. These novel data strongly suggest SAFB1 contributes to the etiology of SCA and Huntington's chorea and that it may be a pathological marker of polyglutamine repeat expansion diseases.
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Affiliation(s)
- Nicola Buckner
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, UK
| | - Kevin C Kemp
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, UK
| | - Helen L Scott
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, UK
| | - Gongyu Shi
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, UK
| | - Caroline Rivers
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, UK
| | - Andriana Gialeli
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, UK
| | - Liang-Fong Wong
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, UK
| | - Oscar Cordero-LLana
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, UK
| | | | - Alastair Wilkins
- Institute of Clinical Neurosciences, Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, UK
| | - James B Uney
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, UK
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9
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Hutter K, Lohmüller M, Jukic A, Eichin F, Avci S, Labi V, Szabo TG, Hoser SM, Hüttenhofer A, Villunger A, Herzog S. SAFB2 Enables the Processing of Suboptimal Stem-Loop Structures in Clustered Primary miRNA Transcripts. Mol Cell 2020; 78:876-889.e6. [PMID: 32502422 DOI: 10.1016/j.molcel.2020.05.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 03/24/2020] [Accepted: 05/08/2020] [Indexed: 12/16/2022]
Abstract
Many microRNAs (miRNAs) are generated from primary transcripts containing multiple clustered stem-loop structures that are thought to be recognized and cleaved by the Microprocessor complex as independent units. Here, we uncover an unexpected mode of processing of the bicistronic miR-15a-16-1 cluster. We find that the primary miR-15a stem-loop is not processed on its own but that the presence of the neighboring primary miR-16-1 stem-loop on the same transcript can compensate for this deficiency in cis. Using a CRISPR/Cas9 screen, we identify SAFB2 (scaffold attachment factor B2) as an essential co-factor in this miR-16-1-assisted pri-miR-15 cleavage and describe SAFB2 as an accessory protein of the Microprocessor. Notably, SAFB2-mediated cleavage expands to other clustered pri-miRNAs, indicating a general mechanism. Together, our study reveals an unrecognized function of SAFB2 in miRNA processing and suggests a scenario in which SAFB2 enables the binding and processing of suboptimal Microprocessor substrates in clustered primary miRNA transcripts.
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Affiliation(s)
- Katharina Hutter
- Institute of Developmental Immunology, Biocenter, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Michael Lohmüller
- Institute of Developmental Immunology, Biocenter, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Almina Jukic
- Institute of Developmental Immunology, Biocenter, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Felix Eichin
- Institute of Developmental Immunology, Biocenter, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Seymen Avci
- Institute of Developmental Immunology, Biocenter, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Verena Labi
- Institute of Developmental Immunology, Biocenter, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Tamas G Szabo
- Institute of Developmental Immunology, Biocenter, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Simon M Hoser
- Institute for Genomics and RNomics, Biocenter, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Alexander Hüttenhofer
- Institute for Genomics and RNomics, Biocenter, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Andreas Villunger
- Institute of Developmental Immunology, Biocenter, Medical University Innsbruck, 6020 Innsbruck, Austria; CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria; Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, 1090 Vienna, Austria
| | - Sebastian Herzog
- Institute of Developmental Immunology, Biocenter, Medical University Innsbruck, 6020 Innsbruck, Austria.
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10
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Matsuda KI, Hashimoto T, Kawata M. Intranuclear Mobility of Estrogen Receptor: Implication for Transcriptional Regulation. Acta Histochem Cytochem 2018; 51:129-136. [PMID: 30279614 PMCID: PMC6160615 DOI: 10.1267/ahc.18023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 07/31/2018] [Indexed: 11/22/2022] Open
Abstract
The estrogen receptor (ER) is a ligand-dependent transcription factor that has two subtypes: ERα and ERβ. ERs regulate transcription of estrogen-responsive genes through interactions with multiple intranuclear components, such as cofactors and the nuclear matrix. Live cell imaging using fluorescent protein-labeled ERs has revealed that ligand-activated ERs are highly mobile in the nucleus, with transient association with the DNA and nuclear matrix. Scaffold attachment factor B (SAFB) 1 and its paralogue, SAFB2, are nuclear matrix-binding proteins that negatively modulate ERα-mediated transcription. Expression of SAFB1 and SAFB2 reduces the mobility of ERα in the presence of ligand. This regulatory machinery is emerging as an epigenetic-like mechanism that alters transcriptional activity through control of intranuclear molecular mobility.
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Affiliation(s)
- Ken Ichi Matsuda
- Department of Anatomy and Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine
| | - Takashi Hashimoto
- Division of Anatomy and Neuroscience, Department of Morphological and Physiological Sciences, University of Fukui Faculty of Medical Sciences
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11
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Ma L, Sun L, Jin X, Xiong SD, Wang JH. Scaffold attachment factor B suppresses HIV-1 infection of CD4 + T cells by preventing binding of RNA polymerase II to HIV-1's long terminal repeat. J Biol Chem 2018; 293:12177-12185. [PMID: 29887524 DOI: 10.1074/jbc.ra118.002018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 06/01/2018] [Indexed: 12/19/2022] Open
Abstract
The 5' end of the HIV, type 1 (HIV-1) long terminal repeat (LTR) promoter plays an essential role in driving viral transcription and productive infection. Multiple host and viral factors regulate LTR activity and modulate HIV-1 latency. Manipulation of the HIV-1 LTR provides a potential therapeutic strategy for combating HIV-1 persistence. In this study, we identified an RNA/DNA-binding protein, scaffold attachment factor B (SAFB1), as a host cell factor that represses HIV-1 transcription. We found that SAFB1 bound to the HIV-1 5' LTR and significantly repressed 5' LTR-driven viral transcription and HIV-1 infection of CD4+ T cells. Mechanistically, SAFB1-mediated repression of HIV-1 transcription and infection was independent of its RNA- and DNA-binding capacities. Instead, by binding to phosphorylated RNA polymerase II, SAFB1 blocked its recruitment to the HIV-1 LTR. Of note, SAFB1-mediated repression of HIV-1 transcription from proviral DNA maintained HIV-1 latency in CD4+ T cells. In summary, our findings reveal that SAFB1 binds to the HIV-1 LTR and physically interacts with phosphorylated RNA polymerase II, repressing HIV-1 transcription initiation and elongation. Our findings improve our understanding of host modulation of HIV-1 transcription and latency and provide a new host cell target for improved anti-HIV-1 therapies.
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Affiliation(s)
- Li Ma
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215006, China; Chinese Academy of Sciences Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200031, China
| | - Li Sun
- Chinese Academy of Sciences Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xia Jin
- Chinese Academy of Sciences Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200031, China
| | - Si-Dong Xiong
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215006, China
| | - Jian-Hua Wang
- Chinese Academy of Sciences Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200031, China.
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12
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Jiao HL, Ye YP, Yang RW, Sun HY, Wang SY, Wang YX, Xiao ZY, He LQ, Cai JJ, Wei WT, Chen YR, Gu CC, Cai YL, Hu YT, Lai QH, Qiu JF, Liang L, Cao GW, Liao WT, Ding YQ. Downregulation of SAFB Sustains the NF- κB Pathway by Targeting TAK1 during the Progression of Colorectal Cancer. Clin Cancer Res 2017; 23:7108-7118. [PMID: 28912140 DOI: 10.1158/1078-0432.ccr-17-0747] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 07/17/2017] [Accepted: 09/07/2017] [Indexed: 11/16/2022]
Abstract
Purpose: To investigate the role and the underlying mechanism of scaffold attachment factor B (SAFB) in the progression of colorectal cancer (CRC).Experimental Design: SAFB expression was analyzed in the Cancer Outlier Profile Analysis of Oncomine and in 175 paraffin-embedded archived CRC tissues. Gene Ontology analyses were performed to explore the mechanism of SAFB in CRC progression. Western blot, RT-PCR, luciferase assay, and chromatin immunoprecipitation (ChIP) were used to detect the regulation of transforming growth factor-β-activated kinase 1 (TAK1) and NF-κB signaling by SAFB The role of SAFB in invasion, metastasis, and angiogenesis was investigated using in vitro and in vivo assays. The relationship between SAFB and TAK1 was analyzed in CRC tissues.Results: SAFB was downregulated in CRC tissues, and low expression of SAFB was significantly associated with an aggressive phenotype and poorer survival of CRC patients. The downregulation of SAFB activated NF-κB signaling by targeting the TAK1 promoter. Ectopic expression of SAFB inhibited the development of aggressive features and metastasis of CRC cells both in vitro and in vivo The overexpression of TAK1 could rescue the aggressive features in SAFB-overexpressed cells. Furthermore, the expression of SAFB in CRC tissues was negatively correlated with the expression of TAK1- and NF-κB-related genes.Conclusions: Our results show that SAFB regulated the activity of NF-κB signaling in CRC by targeting TAK1 This novel mechanism provides a comprehensive understanding of both SAFB and the NF-κB signaling pathway in the progression of CRC and indicates that the SAFB-TAK1-NF-κB axis is a potential target for early therapeutic intervention in CRC progression. Clin Cancer Res; 23(22); 7108-18. ©2017 AACR.
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Affiliation(s)
- Hong-Li Jiao
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Ya-Ping Ye
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Run-Wei Yang
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Hui-Ying Sun
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Shu-Yang Wang
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Yong-Xia Wang
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Zhi-Yuan Xiao
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Liu-Qing He
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Juan-Juan Cai
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Wen-Ting Wei
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Yan-Ru Chen
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Chun-Cai Gu
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Yue-Long Cai
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Yun-Teng Hu
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Qiu-Hua Lai
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Jun-Feng Qiu
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Li Liang
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Guang-Wen Cao
- Department of Epidemiology, Second Military Medical University, Shanghai, China
| | - Wen-Ting Liao
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China. .,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
| | - Yan-Qing Ding
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China. .,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Molecular Tumor Pathology, Guangzhou, China
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13
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The increasing diversity of functions attributed to the SAFB family of RNA-/DNA-binding proteins. Biochem J 2016; 473:4271-4288. [DOI: 10.1042/bcj20160649] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 08/28/2016] [Accepted: 09/02/2016] [Indexed: 12/15/2022]
Abstract
RNA-binding proteins play a central role in cellular metabolism by orchestrating the complex interactions of coding, structural and regulatory RNA species. The SAFB (scaffold attachment factor B) proteins (SAFB1, SAFB2 and SAFB-like transcriptional modulator, SLTM), which are highly conserved evolutionarily, were first identified on the basis of their ability to bind scaffold attachment region DNA elements, but attention has subsequently shifted to their RNA-binding and protein–protein interactions. Initial studies identified the involvement of these proteins in the cellular stress response and other aspects of gene regulation. More recently, the multifunctional capabilities of SAFB proteins have shown that they play crucial roles in DNA repair, processing of mRNA and regulatory RNA, as well as in interaction with chromatin-modifying complexes. With the advent of new techniques for identifying RNA-binding sites, enumeration of individual RNA targets has now begun. This review aims to summarise what is currently known about the functions of SAFB proteins.
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14
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Yamaguchi A, Takanashi K. FUS interacts with nuclear matrix-associated protein SAFB1 as well as Matrin3 to regulate splicing and ligand-mediated transcription. Sci Rep 2016; 6:35195. [PMID: 27731383 PMCID: PMC5059712 DOI: 10.1038/srep35195] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 09/26/2016] [Indexed: 11/23/2022] Open
Abstract
FUS (Fused-in-Sarcoma) is a multifunctional DNA/RNA binding protein linked to familial amyotrophic lateral sclerosis/frontotemporal dementia (ALS/FTD). Since FUS is localized mainly in the nucleus with nucleo-cytoplasmic shuttling, it is critical to understand physiological functions in the nucleus to clarify pathogenesis. Here we report a yeast two-hybrid screening identified FUS interaction with nuclear matrix-associated protein SAFB1 (scaffold attachment factor B1). FUS and SAFB1, abundant in chromatin-bound fraction, interact in a DNA-dependent manner. N-terminal SAP domain of SAFB1, a DNA-binding motif, was required for its localization to chromatin-bound fraction and splicing regulation. In addition, depletion of SAFB1 reduced FUS’s localization to chromatin-bound fraction and splicing activity, suggesting SAFB1 could tether FUS to chromatin compartment thorough N-terminal DNA-binding motif. FUS and SAFB1 also interact with Androgen Receptor (AR) regulating ligand-dependent transcription. Moreover, FUS interacts with another nuclear matrix-associated protein Matrin3, which is muted in a subset of familial ALS cases and reportedly interacts with TDP-43. Interestingly, ectopic ALS-linked FUS mutant sequestered endogenous Matrin3 and SAFB1 in the cytoplasmic aggregates. These findings indicate SAFB1 could be a FUS’s functional platform in chromatin compartment to regulate RNA splicing and ligand-dependent transcription and shed light on the etiological significance of nuclear matrix-associated proteins in ALS pathogenesis.
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Affiliation(s)
- Atsushi Yamaguchi
- Department of Neurobiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Keisuke Takanashi
- Department of Neurobiology, Graduate School of Medicine, Chiba University, Chiba, Japan
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15
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Autoantibody to scaffold attachment factor B (SAFB): A novel connective tissue disease-related autoantibody associated with interstitial lung disease. J Autoimmun 2016; 76:101-107. [PMID: 27682649 DOI: 10.1016/j.jaut.2016.09.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 09/02/2016] [Accepted: 09/13/2016] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To identify and characterize a novel connective tissue disease (CTD)-related autoantibody (autoAb) directed against scaffold attachment factor B (SAFB). METHODS AutoAb specificity was analyzed using RNA and protein-immunoprecipitation assays. Autoimmune targets were affinity purified using patients' sera and subjected to liquid chromatography mass spectrometry. RESULTS By immunoprecipitation assay, 10 sera reacted with a protein with a molecular weight of approximately 160 kDa. Liquid chromatography mass spectrometry of the partially purified autoantigen and additional immunoblot-based analyses revealed that the Ab specifically recognized SAFB. Anti-SAFB Abs were detected in 2 of 646 patients with systemic sclerosis (SSc) (0.3%), 1 of 1570 patients with polymyositis/dermatomyositis (0.06%), 4 of 270 patients with interstitial lung disease (ILD) (1.5%), 1 of 43 patients with overlap syndrome (2.3%) and 2 patients with other diseases including primary Raynaud's disease and eosinophilic pneumonia. Five patients with anti-SAFB Abs had Raynaud's phenomenon and 3 had nail fold punctate hemorrhage. Of note, 8 of the 10 patients (80%) suffered from ILD. None of the patients with anti-SAFB Abs had pulmonary arterial hypertension, heart disease, or renal involvement. CONCLUSIONS Anti-SAFB Ab is a novel CTD-related autoAb possibly associated with ILD.
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16
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Coelho MB, Attig J, Ule J, Smith CWJ. Matrin3: connecting gene expression with the nuclear matrix. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 7:303-15. [PMID: 26813864 DOI: 10.1002/wrna.1336] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 12/18/2015] [Accepted: 12/18/2015] [Indexed: 01/06/2023]
Abstract
As indicated by its name, Matrin3 was discovered as a component of the nuclear matrix, an insoluble fibrogranular network that structurally organizes the nucleus. Matrin3 possesses both DNA- and RNA-binding domains and, consistent with this, has been shown to function at a number of stages in the life cycle of messenger RNAs. These numerous activities indicate that Matrin3, and indeed the nuclear matrix, do not just provide a structural framework for nuclear activities but also play direct functional roles in these activities. Here, we review the structure, functions, and molecular interactions of Matrin3 and of Matrin3-related proteins, and the pathologies that can arise upon mutation of Matrin3. WIREs RNA 2016, 7:303-315. doi: 10.1002/wrna.1336 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Miguel B Coelho
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Jan Attig
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Jernej Ule
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
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17
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Rivers C, Idris J, Scott H, Rogers M, Lee YB, Gaunt J, Phylactou L, Curk T, Campbell C, Ule J, Norman M, Uney JB. iCLIP identifies novel roles for SAFB1 in regulating RNA processing and neuronal function. BMC Biol 2015; 13:111. [PMID: 26694817 PMCID: PMC4689037 DOI: 10.1186/s12915-015-0220-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 12/10/2015] [Indexed: 01/07/2023] Open
Abstract
Background SAFB1 is a RNA binding protein implicated in the regulation of multiple cellular processes such as the regulation of transcription, stress response, DNA repair and RNA processing. To gain further insight into SAFB1 function we used iCLIP and mapped its interaction with RNA on a genome wide level. Results iCLIP analysis found SAFB1 binding was enriched, specifically in exons, ncRNAs, 3’ and 5’ untranslated regions. SAFB1 was found to recognise a purine-rich GAAGA motif with the highest frequency and it is therefore likely to bind core AGA, GAA, or AAG motifs. Confirmatory RT-PCR experiments showed that the expression of coding and non-coding genes with SAFB1 cross-link sites was altered by SAFB1 knockdown. For example, we found that the isoform-specific expression of neural cell adhesion molecule (NCAM1) and ASTN2 was influenced by SAFB1 and that the processing of miR-19a from the miR-17-92 cluster was regulated by SAFB1. These data suggest SAFB1 may influence alternative splicing and, using an NCAM1 minigene, we showed that SAFB1 knockdown altered the expression of two of the three NCAM1 alternative spliced isoforms. However, when the AGA, GAA, and AAG motifs were mutated, SAFB1 knockdown no longer mediated a decrease in the NCAM1 9–10 alternative spliced form. To further investigate the association of SAFB1 with splicing we used exon array analysis and found SAFB1 knockdown mediated the statistically significant up- and downregulation of alternative exons. Further analysis using RNAmotifs to investigate the frequency of association between the motif pairs (AGA followed by AGA, GAA or AAG) and alternative spliced exons found there was a highly significant correlation with downregulated exons. Together, our data suggest SAFB1 will play an important physiological role in the central nervous system regulating synaptic function. We found that SAFB1 regulates dendritic spine density in hippocampal neurons and hence provide empirical evidence supporting this conclusion. Conclusions iCLIP showed that SAFB1 has previously uncharacterised specific RNA binding properties that help coordinate the isoform-specific expression of coding and non-coding genes. These genes regulate splicing, axonal and synaptic function, and are associated with neuropsychiatric disease, suggesting that SAFB1 is an important regulator of key neuronal processes. Electronic supplementary material The online version of this article (doi:10.1186/s12915-015-0220-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Caroline Rivers
- Regenerative Medicine Laboratories, School of Clinical Sciences, Cellular & Molecular Medicine, Medical Sciences Building, University Walk, University of Bristol, Bristol, BS8 1TD, UK.
| | - Jalilah Idris
- Regenerative Medicine Laboratories, School of Clinical Sciences, Cellular & Molecular Medicine, Medical Sciences Building, University Walk, University of Bristol, Bristol, BS8 1TD, UK. .,Institute of Medical Sciences & Technology, University of Kuala Lumpur, Kuala Lumpur, 43000, Malaysia.
| | - Helen Scott
- Regenerative Medicine Laboratories, School of Clinical Sciences, Cellular & Molecular Medicine, Medical Sciences Building, University Walk, University of Bristol, Bristol, BS8 1TD, UK.
| | - Mark Rogers
- Intelligent Systems Laboratory, Department of Engineering & Mathematics, Merchant Venturers Building, University of Bristol, Bristol, BS8 1UB, UK.
| | - Youn-Bok Lee
- MRC Centre for Neurodegeneration Research, King's College London, Institute of Psychiatry, London, UK.
| | - Jessica Gaunt
- Regenerative Medicine Laboratories, School of Clinical Sciences, Cellular & Molecular Medicine, Medical Sciences Building, University Walk, University of Bristol, Bristol, BS8 1TD, UK.
| | - Leonidas Phylactou
- Faculty of Computer and Information Science, University of Ljubljana, Trzaska cesta 25, SI-1001, Ljubljana, Slovenia.
| | - Tomaz Curk
- The Cyprus Institute of Neurology & Genetics, PO Box 23462, 1683, Nicosia, Cyprus.
| | - Colin Campbell
- Institute of Medical Sciences & Technology, University of Kuala Lumpur, Kuala Lumpur, 43000, Malaysia.
| | - Jernej Ule
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK.
| | - Michael Norman
- Regenerative Medicine Laboratories, School of Clinical Sciences, Cellular & Molecular Medicine, Medical Sciences Building, University Walk, University of Bristol, Bristol, BS8 1TD, UK.
| | - James B Uney
- Regenerative Medicine Laboratories, School of Clinical Sciences, Cellular & Molecular Medicine, Medical Sciences Building, University Walk, University of Bristol, Bristol, BS8 1TD, UK.
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18
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Liu HW, Banerjee T, Guan X, Freitas MA, Parvin JD. The chromatin scaffold protein SAFB1 localizes SUMO-1 to the promoters of ribosomal protein genes to facilitate transcription initiation and splicing. Nucleic Acids Res 2015; 43:3605-13. [PMID: 25800734 PMCID: PMC4402547 DOI: 10.1093/nar/gkv246] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 03/11/2015] [Indexed: 01/29/2023] Open
Abstract
Early steps of gene expression are a composite of promoter recognition, promoter activation, RNA synthesis and RNA processing, and it is known that SUMOylation, a post-translational modification, is involved in transcription regulation. We previously found that SUMO-1 marks chromatin at the proximal promoter regions of some of the most active housekeeping genes during interphase in human cells, but the SUMOylated targets on the chromatin remained unclear. In this study, we found that SUMO-1 marks the promoters of ribosomal protein genes via modification of the Scaffold Associated Factor B (SAFB) protein, and the SUMOylated SAFB stimulated both the binding of RNA polymerase to promoters and pre-mRNA splicing. Depletion of SAFB decreased RNA polymerase II binding to promoters and nuclear processing of the mRNA, though mRNA stability was not affected. This study reveals an unexpected role of SUMO-1 and SAFB in the stimulatory coupling of promoter binding, transcription initiation and RNA processing.
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Affiliation(s)
- Hui-wen Liu
- Department of Biomedical Informatics, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA
| | - Tapahsama Banerjee
- Department of Biomedical Informatics, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA
| | - Xiaoyan Guan
- Department of Molecular Virology, Immunology, and Medical Genetics, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA
| | - Michael A Freitas
- Department of Molecular Virology, Immunology, and Medical Genetics, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA
| | - Jeffrey D Parvin
- Department of Biomedical Informatics, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA
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Traweger A, Toepfer S, Wagner RN, Zweimueller-Mayer J, Gehwolf R, Lehner C, Tempfer H, Krizbai I, Wilhelm I, Bauer HC, Bauer H. Beyond cell-cell adhesion: Emerging roles of the tight junction scaffold ZO-2. Tissue Barriers 2014; 1:e25039. [PMID: 24665396 PMCID: PMC3885625 DOI: 10.4161/tisb.25039] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 05/14/2013] [Accepted: 05/14/2013] [Indexed: 01/28/2023] Open
Abstract
Zonula occludens proteins (ZO-1, ZO-2, ZO-3), which belong to the family of membrane-associated guanylate kinase (MAGUK) homologs, serve as molecular hubs for the assembly of multi-protein networks at the cytoplasmic surface of intercellular contacts in epithelial and endothelial cells. These multi-PDZ proteins exert crucial functions in the structural organization of intercellular contacts and in transducing intracellular signals from the plasma membrane to the nucleus. The junctional MAGUK protein ZO-2 not only associates with the C-terminal PDZ-binding motif of various transmembrane junctional proteins but also transiently targets to the nucleus and interacts with a number of nuclear proteins, thereby modulating gene expression and cell proliferation. Recent evidence suggests that ZO-2 is also involved in stress response and cytoprotective mechanisms, which further highlights the multi-faceted nature of this PDZ domain-containing protein. This review focuses on ZO-2 acting as a molecular scaffold at the cytoplasmic aspect of tight junctions and within the nucleus and discusses additional aspects of its cellular activities. The multitude of proteins interacting with ZO-2 and the heterogeneity of proteins either influencing or being influenced by ZO-2 suggests an exceptional functional capacity of this protein far beyond merely serving as a structural component of cellular junctions.
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Affiliation(s)
- Andreas Traweger
- Paracelsus Medical University; Spinal Cord Injury and Tissue Regeneration Center Salzburg; Institute of Tendon and Bone Regeneration; Salzburg, Austria ; Austrian Cluster for Tissue Regeneration; Vienna, Austria
| | - Sebastian Toepfer
- University of Salzburg; Department of Organismic Biology; Salzburg, Austria
| | - Roland N Wagner
- Sanford-Burnham Medical Research Institute; La Jolla, CA USA
| | | | - Renate Gehwolf
- Paracelsus Medical University; Spinal Cord Injury and Tissue Regeneration Center Salzburg; Institute of Tendon and Bone Regeneration; Salzburg, Austria ; Austrian Cluster for Tissue Regeneration; Vienna, Austria
| | - Christine Lehner
- Paracelsus Medical University; Spinal Cord Injury and Tissue Regeneration Center Salzburg; Institute of Tendon and Bone Regeneration; Salzburg, Austria ; Austrian Cluster for Tissue Regeneration; Vienna, Austria
| | - Herbert Tempfer
- Paracelsus Medical University; Spinal Cord Injury and Tissue Regeneration Center Salzburg; Institute of Tendon and Bone Regeneration; Salzburg, Austria ; Austrian Cluster for Tissue Regeneration; Vienna, Austria
| | - Istvan Krizbai
- Institute of Biophysics; Biological Research Centre; Szeged, Hungary
| | - Imola Wilhelm
- Institute of Biophysics; Biological Research Centre; Szeged, Hungary
| | - Hans-Christian Bauer
- Paracelsus Medical University; Spinal Cord Injury and Tissue Regeneration Center Salzburg; Institute of Tendon and Bone Regeneration; Salzburg, Austria ; Austrian Cluster for Tissue Regeneration; Vienna, Austria ; University of Salzburg; Department of Organismic Biology; Salzburg, Austria
| | - Hannelore Bauer
- Paracelsus Medical University; Spinal Cord Injury and Tissue Regeneration Center Salzburg; Institute of Tendon and Bone Regeneration; Salzburg, Austria ; University of Salzburg; Department of Organismic Biology; Salzburg, Austria
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Abstract
This review summarizes the current understanding of the role of nuclear bodies in regulating gene expression. The compartmentalization of cellular processes, such as ribosome biogenesis, RNA processing, cellular response to stress, transcription, modification and assembly of spliceosomal snRNPs, histone gene synthesis and nuclear RNA retention, has significant implications for gene regulation. These functional nuclear domains include the nucleolus, nuclear speckle, nuclear stress body, transcription factory, Cajal body, Gemini of Cajal body, histone locus body and paraspeckle. We herein review the roles of nuclear bodies in regulating gene expression and their relation to human health and disease.
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Affiliation(s)
| | - Cornelius F. Boerkoel
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-604-875-2157; Fax: +1-604-875-2376
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Scaffold attachment factor B1 regulates the androgen receptor in concert with the growth inhibitory kinase MST1 and the methyltransferase EZH2. Oncogene 2013; 33:3235-45. [PMID: 23893242 DOI: 10.1038/onc.2013.294] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 04/12/2013] [Accepted: 05/07/2013] [Indexed: 12/16/2022]
Abstract
The androgen receptor (AR) is a transcription factor that employs many diverse interactions with coregulatory proteins in normal physiology and in prostate cancer (PCa). The AR mediates cellular responses in association with chromatin complexes and kinase cascades. Here we report that the nuclear matrix protein, scaffold attachment factor B1 (SAFB1), regulates AR activity and AR levels in a manner that suggests its involvement in PCa. SAFB1 mRNA expression was lower in PCa in comparison with normal prostate tissue in a majority of publicly available RNA expression data sets. SAFB1 protein levels were also reduced with disease progression in a cohort of human PCa that included metastatic tumors. SAFB1 bound to AR and was phosphorylated by the MST1 (Hippo homolog) serine-threonine kinase, previously shown to be an AR repressor, and MST1 localization to AR-dependent promoters was inhibited by SAFB1 depletion. Knockdown of SAFB1 in androgen-dependent LNCaP PCa cells increased AR and prostate-specific antigen (PSA) levels, stimulated growth of cultured cells and subcutaneous xenografts and promoted a more aggressive phenotype, consistent with a repressive AR regulatory function. SAFB1 formed a complex with the histone methyltransferase EZH2 at AR-interacting chromatin sites in association with other polycomb repressive complex 2 (PRC2) proteins. We conclude that SAFB1 acts as a novel AR co-regulator at gene loci where signals from the MST1/Hippo and EZH2 pathways converge.
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Abstract
SAFB1 (scaffold attachment factor B1) and a second family member SAFB2, are multifunctional proteins implicated in a variety of cellular processes including cell growth, apoptosis and stress response. Their potential function as tumour suppressors has been proposed based on well-described roles in tran-scriptional repression. The present review summarizes the current knowledge of SAFB1 and SAFB2 proteins in transcriptional repression with relevance to cancer.
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23
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de Thonel A, Le Mouël A, Mezger V. Transcriptional regulation of small HSP-HSF1 and beyond. Int J Biochem Cell Biol 2012; 44:1593-612. [PMID: 22750029 DOI: 10.1016/j.biocel.2012.06.012] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 06/07/2012] [Accepted: 06/08/2012] [Indexed: 12/16/2022]
Abstract
The members of the small heat shock protein (sHSP) family are molecular chaperones that play major roles in development, stress responses, and diseases, and have been envisioned as targets for therapy, particularly in cancer. The molecular mechanisms that regulate their transcription, in normal, stress, or pathological conditions, are characterized by extreme complexity and subtlety. Although historically linked to the heat shock transcription factors (HSFs), the stress-induced or developmental expression of the diverse members, including HSPB1/Hsp27/Hsp25, αA-crystallin/HSPB4, and αB-crystallin/HSPB5, relies on the combinatory effects of many transcription factors. Coupled with remarkably different cis-element architectures in the sHsp regulatory regions, they confer to each member its developmental expression or stress-inducibility. For example, multiple regulatory pathways coordinate the spatio-temporal expression of mouse αA-, αB-crystallin, and Hsp25 genes during lens development, through the action of master genes, like the large Maf family proteins and Pax6, but also HSF4. The inducibility of Hsp27 and αB-crystallin transcription by various stresses is exerted by HSF-dependent mechanisms, by which concomitant induction of Hsp27 and αB-crystallin expression is observed. In contrast, HSF-independent pathways can lead to αB-crystallin expression, but not to Hsp27 induction. Not surprisingly, deregulation of the expression of sHSP is associated with various pathologies, including cancer, neurodegenerative, or cardiac diseases. However, many questions remain to be addressed, and further elucidation of the developmental mechanisms of sHsp gene transcription might help to unravel the tissue- and stage-specific functions of this fascinating class of proteins, which might prove to be crucial for future therapeutic strategies. This article is part of a Directed Issue entitled: Small HSPs in physiology and pathology.
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24
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Effect of transfection with PLP2 antisense oligonucleotides on gene expression of cadmium-treated MDA-MB231 breast cancer cells. Anal Bioanal Chem 2012; 405:1893-901. [PMID: 22729357 DOI: 10.1007/s00216-012-6182-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 05/23/2012] [Accepted: 06/04/2012] [Indexed: 10/28/2022]
Abstract
Emerging evidence indicates that cadmium (Cd) is able to regulate gene expression, drastically affecting the pattern of transcriptional activity in human normal and pathological cells. We have already shown that exposure of MDA-MB231 breast cancer cells to 5 μM CdCl(2) for 96 h, apart from significantly affecting mitochondrial metabolism, induces modifications of the expression level of genes coding for members of stress response-, mitochondrial respiration-, MAP kinase-, NF-κB-, and apoptosis-related pathways. In the present study, we have expanded the knowledge on the biological effects of Cd-breast cancer cell interactions, indicating PLP2 (proteolipid protein-2) as a novel member of the list of Cd-upregulated genes by MDA-MB231 cancer cells and, through the application of transfection techniques with specific antisense oligonucleotides, we have demonstrated that such over-expression may be an upstream event to some of the changes of gene expression levels already observed in Cd-treated cells, thus unveiling new possible molecular relationship between PLP2 and genes linked to the stress and apoptotic responses.
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Lehner C, Gehwolf R, Tempfer H, Krizbai I, Hennig B, Bauer HC, Bauer H. Oxidative stress and blood-brain barrier dysfunction under particular consideration of matrix metalloproteinases. Antioxid Redox Signal 2011; 15:1305-23. [PMID: 21294658 PMCID: PMC6464004 DOI: 10.1089/ars.2011.3923] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
A cell's "redox" (oxidation and reduction) state is determined by the sum of all redox processes yielding reactive oxygen species (ROS), reactive nitrogen species (RNS), and other reactive intermediates. Low amounts of ROS/RNS are generated by different mechanisms in every cell and are important regulatory mediators in many signaling processes (redox signaling). When the physiological balance between the generation and elimination of ROS/RNS is disrupted, oxidative/nitrosative stress with persistent oxidative damage of the organism occurs. Oxidative stress has been suggested to act as initiator and/or mediator of many human diseases. The cerebral vasculature is particularly susceptible to oxidative stress, which is critical since cerebral endothelial cells play a major role in the creation and maintenance of the blood-brain barrier (BBB). This article will only contain a focused introduction on the biochemical background of redox signaling, since this has been reported already in a series of excellent recent reviews. The goal of this work is to increase the understanding of basic mechanisms underlying ROS/RNS-induced BBB disruption, with a focus on the role of matrix metalloproteinases, which, after all, appear to be a key mediator in the initiation and progression of BBB damage elicited by oxidative stress.
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Affiliation(s)
- Christine Lehner
- Department of Organismic Biology, Development Biology Group, University Hospital of Salzburg, Salzburg, Austria
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26
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Lisse TS, Hewison M, Adams JS. Hormone response element binding proteins: novel regulators of vitamin D and estrogen signaling. Steroids 2011; 76:331-9. [PMID: 21236284 PMCID: PMC3042887 DOI: 10.1016/j.steroids.2011.01.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/04/2011] [Accepted: 01/05/2011] [Indexed: 01/11/2023]
Abstract
Insights from vitamin D-resistant New World primates and their human homologues as models of natural and pathological insensitivity to sterol/steroid action have uncovered a family of novel intracellular vitamin D and estrogen regulatory proteins involved in hormone action. The proteins, known as "vitamin D or estrogen response element-binding proteins", behave as potent cis-acting, transdominant regulators to inhibit steroid receptor binding to DNA response elements and is responsible for vitamin D and estrogen resistances. This set of interactors belongs to the heterogeneous nuclear ribonucleoprotein (hnRNP) family of previously known pre-mRNA-interacting proteins. This review provides new insights into the mechanism by which these novel regulators of signaling and metabolism can act to regulate responses to vitamin D and estrogen. In addition the review also describes other molecules that are known to influence nuclear receptor signaling through interaction with hormone response elements.
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Affiliation(s)
- Thomas S Lisse
- Department of Orthopaedic Surgery and Molecular Biology Institute, David Geffen School of Medicine at UCLA, 615 Charles E. Young Drive South, Los Angeles, CA 90095, USA.
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27
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New aspects of the molecular constituents of tissue barriers. J Neural Transm (Vienna) 2010; 118:7-21. [PMID: 20865434 DOI: 10.1007/s00702-010-0484-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 08/30/2010] [Indexed: 01/24/2023]
Abstract
Epithelial and endothelial tissue barriers are based on tight intercellular contacts (Tight Junctions, TJs) between neighbouring cells. TJs are multimeric complexes, located at the most apical border of the lateral membrane. So far, a plethora of proteins locating at tight intercellular contacts have been discovered, the role of which has just partly been unraveled. Yet, there is convincing evidence that many TJ proteins exert a dual role: They act as structural components at the junctional site and they are involved in signalling pathways leading to alterations of gene expression and cell behaviour (migration, proliferation). This review will shortly summarize the classical functions of TJs and TJ-related proteins and will introduce a new category, termed the "non-classical" functions of junctional proteins. A particular focus will be directed towards the nuclear targeting of junctional proteins and the downstream effects elicited by their intranuclear activities.
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28
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Garee JP, Oesterreich S. SAFB1's multiple functions in biological control-lots still to be done! J Cell Biochem 2010; 109:312-9. [PMID: 20014070 DOI: 10.1002/jcb.22420] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The examination of scaffold attachment factor B1 (SAFB1) and its multiple functions and tasks in cellular processes provides insight into its role in diseases, such as cancer. SAFB1 is a large multi-domain protein with well-described functions in transcriptional repression, and RNA splicing. It is ubiquitously expressed, and has been shown to be important in numerous cellular processes including cell growth, stress response, and apoptosis. SAFB1 is part of a protein family with at least two other family members, SAFB2 and the SAFB-like transcriptional modulator SLTM. The goal of this prospect article is to summarize known functions of SAFB1, and its roles in cellular processes, but also to speculate on less well described, novel attributes of SAFB1, such as a potential role in chromatin organization. This timely review shows aspects of SAFB1, which are proving to have a complexity far greater than was previously thought.
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Affiliation(s)
- Jason P Garee
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, USA
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29
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The dual role of zonula occludens (ZO) proteins. J Biomed Biotechnol 2010; 2010:402593. [PMID: 20224657 PMCID: PMC2836178 DOI: 10.1155/2010/402593] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 01/06/2010] [Indexed: 02/07/2023] Open
Abstract
ZO (zonula occludens) proteins are scaffolding proteins providing the structural basis for the assembly of multiprotein complexes at the cytoplasmic surface of intercellular junctions. In addition, they provide a link between the integral membrane proteins and the filamentous cytoskeleton. ZO proteins belong to the large family of membrane-associated guanylate kinase (MAGUK)-like proteins comprising a number of subfamilies based on domain content and sequence similarity. Besides their structural function at cell-cell contacts, ZO proteins appear to participate in the regulation of cell growth and proliferation. Detailed molecular studies have shown that ZO proteins exhibit conserved functional nuclear localization and nuclear export motifs within their amino acid sequence. Further, ZO proteins interact with dual residency proteins localizing to the plasma membrane and the nucleus. Although the nuclear targeting of ZO proteins has well been described, many questions concerning the biological significance of this process have remained open. This review focuses on the dual role of ZO proteins, being indispensable structural components at the junctional site and functioning in signal transduction pathways related to gene expression and cell behavior.
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30
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Hammerich-Hille S, Kaipparettu BA, Tsimelzon A, Creighton CJ, Jiang S, Polo JM, Melnick A, Meyer R, Oesterreich S. SAFB1 mediates repression of immune regulators and apoptotic genes in breast cancer cells. J Biol Chem 2010; 285:3608-3616. [PMID: 19901029 PMCID: PMC2823501 DOI: 10.1074/jbc.m109.066431] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 11/04/2009] [Indexed: 12/18/2022] Open
Abstract
The scaffold attachment factors SAFB1 and SAFB2 are paralogs, which are involved in cell cycle regulation, apoptosis, differentiation, and stress response. They have been shown to function as estrogen receptor corepressors, and there is evidence for a role in breast tumorigenesis. To identify their endogenous target genes in MCF-7 breast cancer cells, we utilized a combined approach of chromatin immunoprecipitation (ChIP)-on-chip and gene expression array studies. By performing ChIP-on-chip on microarrays containing 24,000 promoters, we identified 541 SAFB1/SAFB2-binding sites in promoters of known genes, with significant enrichment on chromosomes 1 and 6. Gene expression analysis revealed that the majority of target genes were induced in the absence of SAFB1 or SAFB2 and less were repressed. Interestingly, there was no significant overlap between the genes identified by ChIP-on-chip and gene expression array analysis, suggesting regulation through regions outside the proximal promoters. In contrast to SAFB2, which shared most of its target genes with SAFB1, SAFB1 had many unique target genes, most of them involved in the regulation of the immune system. A subsequent analysis of the estrogen treatment group revealed that 12% of estrogen-regulated genes were dependent on SAFB1, with the majority being estrogen-repressed genes. These were primarily genes involved in apoptosis, such as BBC3, NEDD9, and OPG. Thus, this study confirms the primary role of SAFB1/SAFB2 as corepressors and also uncovers a previously unknown role for SAFB1 in the regulation of immune genes and in estrogen-mediated repression of genes.
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Affiliation(s)
- Stephanie Hammerich-Hille
- From the Lester and Sue Smith Breast Center, Department of Medicine and Molecular and Cellular Biology, Texas Children's Cancer Center, Houston, Texas 77030
| | - Benny A Kaipparettu
- From the Lester and Sue Smith Breast Center, Department of Medicine and Molecular and Cellular Biology, Texas Children's Cancer Center, Houston, Texas 77030
| | - Anna Tsimelzon
- From the Lester and Sue Smith Breast Center, Department of Medicine and Molecular and Cellular Biology, Texas Children's Cancer Center, Houston, Texas 77030
| | - Chad J Creighton
- From the Lester and Sue Smith Breast Center, Department of Medicine and Molecular and Cellular Biology, Texas Children's Cancer Center, Houston, Texas 77030
| | - Shiming Jiang
- From the Lester and Sue Smith Breast Center, Department of Medicine and Molecular and Cellular Biology, Texas Children's Cancer Center, Houston, Texas 77030
| | - Jose M Polo
- the Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Ari Melnick
- the Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Rene Meyer
- Department of Pediatric Hematology/Oncology, Texas Children's Cancer Center, Houston, Texas 77030 and
| | - Steffi Oesterreich
- From the Lester and Sue Smith Breast Center, Department of Medicine and Molecular and Cellular Biology, Texas Children's Cancer Center, Houston, Texas 77030; Department of Pediatric Hematology/Oncology, Texas Children's Cancer Center, Houston, Texas 77030 and.
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31
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Tsianou D, Nikolakaki E, Tzitzira A, Bonanou S, Giannakouros T, Georgatsou E. The enzymatic activity of SR protein kinases 1 and 1a is negatively affected by interaction with scaffold attachment factors B1 and 2. FEBS J 2009; 276:5212-27. [PMID: 19674106 DOI: 10.1111/j.1742-4658.2009.07217.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
SR protein kinases (SRPKs) phosphorylate Ser/Arg dipeptide-containing proteins that play crucial roles in a broad spectrum of basic cellular processes. Phosphorylation by SRPKs constitutes a major way of regulating such cellular mechanisms. In the past, we have shown that SRPK1a interacts with the nuclear matrix protein scaffold attachment factor B1 (SAFB1) via its unique N-terminal domain, which differentiates it from SRPK1. In this study, we show that SAFB1 inhibits the activity of both SRPK1a and SRPK1 in vitro and that its RE-rich region is redundant for the observed inhibition. We demonstrate that kinase activity inhibition is caused by direct binding of SAFB1 to SRPK1a and SRPK1, and we also present evidence for the in vitro binding of SAFB2 to the two kinases, albeit with different affinity. Moreover, we show that both SR protein kinases can form complexes with both scaffold attachment factors B in living cells and that this interaction is capable of inhibiting their activity, depending on the tenacity of the complex formed. Finally, we present data demonstrating that SRPK/SAFB complexes are present in the nucleus of HeLa cells and that the enzymatic activity of the nuclear matrixlocalized SRPK1 is repressed. These results suggest a new role for SAFB proteins as regulators of SRPK activity and underline the importance of the assembly of transient intranuclear complexes in cellular regulation.
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Affiliation(s)
- Dora Tsianou
- Department of Medicine, University of Thessaly, Mezourlo, 41110 Larissa, Greece
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32
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Zeng Y, Kulkarni P, Inoue T, Getzenberg RH. Down-regulating cold shock protein genes impairs cancer cell survival and enhances chemosensitivity. J Cell Biochem 2009; 107:179-88. [PMID: 19277990 DOI: 10.1002/jcb.22114] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The microenvironment of the cancer cell is pivotal to its phenotypic regulation. One of the central components of the microenvironment is temperature. An elevation in environmental temperature has been shown to increase the cancer cell's susceptibility to chemo- and radiation therapy. The goal of the studies described here was to identify some of the pathways that are modified by a mild increase in temperature in cancer cells. Using prostate cancer cells as a model system we found that in addition to the well described and anticipated up-regulation of the heat shock family of proteins, there is a significant down-regulation of certain members of the "cold shock" family of proteins such as, RNA binding motif protein 3 (RBM3) and cold inducible RNA binding protein (CIRBP). siRNA-mediated down-regulation of the cold shock protein (CSP) encoding mRNAs dramatically attenuates cell survival in the absence of any heat application. Furthermore, we also demonstrate that knocking down the CSPs can enhance the therapeutic response of prostate cancer cells to chemotherapy. Our findings suggest that down-regulating CSPs in cancer cells may "mimic" the stress response the cells experience when exposed to heat treatment rendering them more susceptible to therapy. Thus, the pharmacological modulation of RBM3 and CIRBP may represent novel therapeutic approaches for prostate cancer.
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Affiliation(s)
- Yu Zeng
- Department of Urology, James Buchanan Brady Urological Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
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33
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Increase in the levels of chaperone proteins by exposure to β-estradiol, bisphenol A and 4-methoxyphenol in human cells transfected with estrogen receptor α cDNA. Toxicol In Vitro 2009; 23:728-35. [DOI: 10.1016/j.tiv.2009.02.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 12/08/2008] [Accepted: 02/22/2009] [Indexed: 11/21/2022]
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34
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Omura Y, Nishio Y, Takemoto T, Ikeuchi C, Sekine O, Morino K, Maeno Y, Obata T, Ugi S, Maegawa H, Kimura H, Kashiwagi A. SAFB1, an RBMX-binding protein, is a newly identified regulator of hepatic SREBP-1c gene. BMB Rep 2009; 42:232-7. [DOI: 10.5483/bmbrep.2009.42.4.232] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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35
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Albrethsen J, Knol JC, Jimenez CR. Unravelling the nuclear matrix proteome. J Proteomics 2008; 72:71-81. [PMID: 18957335 DOI: 10.1016/j.jprot.2008.09.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Revised: 09/29/2008] [Accepted: 09/30/2008] [Indexed: 12/28/2022]
Abstract
The nuclear matrix (NM) model posits the presence of a protein/RNA scaffold that spans the mammalian nucleus. The NM proteins are involved in basic nuclear function and are a promising source of protein biomarkers for cancer. Importantly, the NM proteome is operationally defined as the proteins from cells and tissue that are extracted following a specific biochemical protocol; in brief, the soluble proteins and lipids, cytoskeleton, and chromatin elements are removed in a sequential fashion, leaving behind the proteins that compose the NM. So far, the NM has not been sufficiently verified as a biological entity and only preliminary at the molecular level. Here, we argue for a combined effort of proteomics, immunodetection and microscopy to unravel the composition and structure of the NM.
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Affiliation(s)
- Jakob Albrethsen
- OncoProteomics Laboratory, CCA 1-60, Department Medical Oncology, VUmc-Cancer Center Amsterdam, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
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36
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Sirchia R, Longo A, Luparello C. Cadmium regulation of apoptotic and stress response genes in tumoral and immortalized epithelial cells of the human breast. Biochimie 2008; 90:1578-90. [PMID: 18625282 DOI: 10.1016/j.biochi.2008.06.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Accepted: 06/19/2008] [Indexed: 01/23/2023]
Abstract
Cadmium (Cd) is a widely-disseminated metal which can be imported and accumulated in living cells thereby drastically interfering with their biological mechanisms. Increasing interest has been recently focused on the elucidation of the cellular and molecular aspects of Cd-dependent regulation of gene expression and signal transduction pathways in different model system. Concerning breast cancer, very limited studies have been produced so far on the role played by Cd on estrogen receptor-negative human breast cancer cells, that are expected to be insensitive to the already-proven metallo-estrogenic effect exerted by Cd on the estrogen receptor-positive cell counterparts. Here, we have examined the effects of long-term (96 h) exposure of estrogen receptor-negative MDA-MB231 malignant adenocarcinoma cells to CdCl(2) at 5 microM concentration, corresponding to the IC(50) for this time of incubation, by evaluating the expression levels of genes coding for stress response factors (e.g. heat shock proteins and metallothioneins), and for apoptosis-related factors and enzymes. In parallel, we tested the gene expression pattern of immortalized HB2 breast epithelial cells, taken as non-tumoral counterpart, after the same exposure to the metal which instead did not exert any change in their cell number with respect to controls. Our cumulative results indicate that, whilst HB2 cells appear to activate defense mechanisms against metal stress principally via metallothionein massive up-regulation and appearance of the spliced form of XBP-1 message, MDA-MB231 cells seem to couple the onset of a protective reaction (e.g. up-regulation of hsp27 and metallothioneins) to the switching-on of new intracellular pathways directing cells to a kind of death which shares several aspects with the apoptotic program, such as down-regulation of Bcl-2 and over-expression of Dap kinase and several caspases.
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Affiliation(s)
- Rosalia Sirchia
- Dipartimento di Biologia Cellulare e dello Sviluppo, Viale delle Scienze, Università di Palermo, Palermo, Italy
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Lee YB, Colley S, Norman M, Biamonti G, Uney JB. SAFB re-distribution marks steps of the apoptotic process. Exp Cell Res 2007; 313:3914-23. [PMID: 17643427 DOI: 10.1016/j.yexcr.2007.06.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Revised: 06/07/2007] [Accepted: 06/26/2007] [Indexed: 02/02/2023]
Abstract
We have found novel functions of scaffold attachment factor-B1 (SAFB) during apoptosis. The experiments showed that SAFB moved into the nucleolus 15 min after the induction of apoptosis and before the release of cytochrome c into the cytoplasm. Two hours later SAFB formed a peri-nucleolar ring-like structure and this occurred after cytochrome c release and before PARP cleavage. Digestion with RNase suggested that the peri-nucleolar ring structure was dependent on RNA integrity and a RNA moiety formed part of this structure. Studies using SAFB deletion mutants showed that the formation of the peri-nucleolar structure was not mediated by the DNA binding (SAP) or the RNA binding (RRM) domain of SAFB but was instead dependent on the S/K and R/E coiled-coil regions: a result suggesting that the structure is formed via protein interactions. In addition, SAFB cleavage was shown to be mediated by caspase-3 and occurred after the formation of the peri-nucleolar ring and after cleavage of PARP (characteristic of proteins having a direct role in apoptosis). A determinant for this cleavage is located in the DNA binding domain and we hypothesize that SAFB may direct the reorganization and segregation of nuclear RNA and DNA prior to endonuclease-mediated DNA cleavage.
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Affiliation(s)
- Youn-Bok Lee
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Bristol University, Dorothy Hodgkin Building, Whitson Street Bristol BS1 3NY, UK
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Chan C, Lee YB, Uney J, Flynn A, Tobias J, Norman M. A novel member of the SAF (scaffold attachment factor)-box protein family inhibits gene expression and induces apoptosis. Biochem J 2007; 407:355-62. [PMID: 17630952 PMCID: PMC2275068 DOI: 10.1042/bj20070170] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The SLTM [SAF (scaffold attachment factor)-like transcription modulator] protein contains a SAF-box DNA-binding motif and an RNA-binding domain, and shares an overall identity of 34% with SAFB1 {scaffold attachment factor-B1; also known as SAF-B (scaffold attachment factor B), HET [heat-shock protein 27 ERE (oestrogen response element) and TATA-box-binding protein] or HAP (heterogeneous nuclear ribonucleoprotein A1-interacting protein)}. Here, we show that SLTM is localized to the cell nucleus, but excluded from nucleoli, and to a large extent it co-localizes with SAFB1. In the nucleus, SLTM has a punctate distribution and it does not co-localize with SR (serine/arginine) proteins. Overexpression of SAFB1 has been shown to exert a number of inhibitory effects, including suppression of oestrogen signalling. Although SLTM also suppressed the ability of oestrogen to activate a reporter gene in MCF-7 breast-cancer cells, inhibition of a constitutively active beta-galactosidase gene suggested that this was primarily the consequence of a generalized inhibitory effect on transcription. Measurement of RNA synthesis, which showed a particularly marked inhibition of [(3)H]uridine incorporation into mRNA, supported this conclusion. In addition, analysis of cell-cycle parameters, chromatin condensation and cytochrome c release showed that SLTM induced apoptosis in a range of cultured cell lines. Thus the inhibitory effects of SLTM on gene expression appear to result from generalized down-regulation of mRNA synthesis and initiation of apoptosis consequent upon overexpressing the protein. While indicating a crucial role for SLTM in cellular function, these results also emphasize the need for caution when interpreting phenotypic changes associated with manipulation of protein expression levels.
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Affiliation(s)
- Ching Wan Chan
- *Henry Wellcome Laboratories for Integrative Neurosciences and Endocrinology, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, U.K
| | - Youn-Bok Lee
- *Henry Wellcome Laboratories for Integrative Neurosciences and Endocrinology, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, U.K
| | - James Uney
- *Henry Wellcome Laboratories for Integrative Neurosciences and Endocrinology, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, U.K
| | - Andrea Flynn
- *Henry Wellcome Laboratories for Integrative Neurosciences and Endocrinology, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, U.K
| | - Jonathan H. Tobias
- †Rheumatology Unit, University of Bristol, Bristol Royal Infirmary, Bristol BS2 8HW, U.K
| | - Michael Norman
- *Henry Wellcome Laboratories for Integrative Neurosciences and Endocrinology, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, U.K
- To whom correspondence should be addressed (email )
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Traweger A, Lehner C, Farkas A, Krizbai IA, Tempfer H, Klement E, Guenther B, Bauer HC, Bauer H. Nuclear Zonula occludens-2 alters gene expression and junctional stability in epithelial and endothelial cells. Differentiation 2007; 76:99-106. [PMID: 17973926 DOI: 10.1111/j.1432-0436.2007.00227.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Zonula occludens proteins (ZOPs) are essential scaffold proteins involved in the organization of epithelial and endothelial intercellular junctions. Based on their molecular domain architecture, they are members of the large family of membrane-associated guanylate kinase-like (MAGUK) proteins. As all other MAGUKs, ZOPs contain a core of several PDZ, an src homology-3, and a guanylate kinase-like domain, indicating that these proteins may serve both structural and signaling functions. In addition, ZOPs exhibit some unique motifs not shared by other MAGUKs, i.e., several nuclear localization (NLS) and nuclear export signals (NES), allowing these proteins to shuttle between the cytoplasm and the nucleus. However, the stimuli leading to the nuclear accumulation of ZOPs and the resulting physiological consequences remain poorly defined. We have previously reported the direct binding of nuclear ZO-2 to scaffold attachment factor B, a heterogeneous nuclear ribonucleoprotein involved in chromatin organization and the transcriptional control of eukaryotic genes. We now report that the nuclear accumulation of ZO-2 leads to an increase in the expression of the M2 type of pyruvate kinase (M2-PK) in epithelial and endothelial cells. Further, the proliferative activity was increased, while the intercellular junctional stability of Madin-Darby canine kidney cells was reduced. Our data provide evidence to suggest that ZO-2 exerts a junction-unrelated function that further supports the notion of a general "dual" role of junctional MAGUKs, being an indispensable structural component at cell-cell junctions and a nuclear factor influencing gene expression and cell behavior.
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Affiliation(s)
- Andreas Traweger
- Developmental Biology Group, Department of Organismic Biology, University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria
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Heldring N, Pike A, Andersson S, Matthews J, Cheng G, Hartman J, Tujague M, Ström A, Treuter E, Warner M, Gustafsson JA. Estrogen receptors: how do they signal and what are their targets. Physiol Rev 2007; 87:905-31. [PMID: 17615392 DOI: 10.1152/physrev.00026.2006] [Citation(s) in RCA: 1245] [Impact Index Per Article: 73.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
During the past decade there has been a substantial advance in our understanding of estrogen signaling both from a clinical as well as a preclinical perspective. Estrogen signaling is a balance between two opposing forces in the form of two distinct receptors (ER alpha and ER beta) and their splice variants. The prospect that these two pathways can be selectively stimulated or inhibited with subtype-selective drugs constitutes new and promising therapeutic opportunities in clinical areas as diverse as hormone replacement, autoimmune diseases, prostate and breast cancer, and depression. Molecular biological, biochemical, and structural studies have generated information which is invaluable for the development of more selective and effective ER ligands. We have also become aware that ERs do not function by themselves but require a number of coregulatory proteins whose cell-specific expression explains some of the distinct cellular actions of estrogen. Estrogen is an important morphogen, and many of its proliferative effects on the epithelial compartment of glands are mediated by growth factors secreted from the stromal compartment. Thus understanding the cross-talk between growth factor and estrogen signaling is essential for understanding both normal and malignant growth. In this review we focus on several of the interesting recent discoveries concerning estrogen receptors, on estrogen as a morphogen, and on the molecular mechanisms of anti-estrogen signaling.
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Affiliation(s)
- Nina Heldring
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
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41
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Matter K, Balda MS. Epithelial tight junctions, gene expression and nucleo-junctional interplay. J Cell Sci 2007; 120:1505-11. [PMID: 17452622 DOI: 10.1242/jcs.005975] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Tight junctions are components of the junctional complex linking neighbouring epithelial cells and are important for barrier formation. Recent evidence suggests that tight junctions also participate in signal transduction mechanisms that regulate epithelial cell proliferation, gene expression, differentiation and morphogenesis. One important class of tight-junction-associated signal transduction mechanism is based on dual localisation of certain proteins both at junctions and in the nucleus. These proteins and their partners participate in various steps of gene expression, ranging from regulation of transcription and chromatin structure to mRNA processing and translation. In cancer tissues, their expression is often deregulated in a manner that suggests that tight junctions function as suppressors of proliferation and transformation.
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Affiliation(s)
- Karl Matter
- Division of Cell Biology, Institute of Ophthalmology, University College London, Bath Street, London, EC1V 9EL, UK.
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Sergeant KA, Bourgeois CF, Dalgliesh C, Venables JP, Stevenin J, Elliott DJ. Alternative RNA splicing complexes containing the scaffold attachment factor SAFB2. J Cell Sci 2007; 120:309-19. [PMID: 17200140 DOI: 10.1242/jcs.03344] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The scaffold attachment factor SAFB1 and its recently discovered homologue SAFB2 might provide an important link between pre-mRNA splicing, intracellular signalling and transcription. Using novel mono-specific antisera, we found endogenous SAFB2 protein has a different spatial distribution from SAFB1 within the nucleus where it is found in much larger nuclear complexes (up to 670 kDa in size), and a distinct pattern of expression in adult human testis. By contrast, SAFB1 protein predominantly exists either as smaller complexes or as a monomeric protein. Our results suggest stable core complexes containing components comprised of SAFB1, SAFB2 and the RNA binding proteins Sam68 and hnRNPG exist in parallel with free SAFB1 protein. We found that SAFB2 protein, like SAFB1, acts as a negative regulator of a tra2β variable exon. Despite showing an involvement in splicing, we detected no stable interaction between SAFB proteins and SR or SR-related splicing regulators, although these were also found in stable higher molecular mass complexes. Each of the detected alternative splicing regulator complexes exists independently of intact nucleic acids, suggesting they might be pre-assembled and recruited to nascent transcripts as modules to facilitate alternative splicing, and/or they represent nuclear storage compartments from which active proteins are recruited.
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Affiliation(s)
- Kate A Sergeant
- Institute of Human Genetics, University of Newcastle, International Centre for Life, Central Parkway, Newcastle, NE1 3BZ, UK
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43
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Abstract
The DNA in eukaryotic genome is compartmentalized into various domains by a series of loops tethered onto the base of nuclear matrix. Scaffold/ Matrix attachment regions (S/MAR) punctuate these attachment sites and govern the nuclear architecture by establishing chromatin boundaries. In this context, specific proteins that interact with and bind to MAR sequences called MAR binding proteins (MARBPs), are of paramount importance, as these sequences spool the proteins that regulate transcription, replication, repair and recombination. Recent evidences also suggest a role for these cis-acting elements in viral integration, replication and transcription, thereby affecting host immune system. Owing to the complex nature of these nucleotide sequences, less is known about the MARBPs that bind to and bring about diverse effects on chromatin architecture and gene function. Several MARBPs have been identified and characterized so far and the list is growing. The fact that most the MARBPs exist in a co-repressor/ co-activator complex and bring about gene regulation makes them quintessential for cellular processes. This participation in gene regulation means that any perturbation in the regulation and levels of MARBPs could lead to disease conditions, particularly those caused by abnormal cell proliferation, like cancer. In the present chapter, we discuss the role of MARs and MARBPs in eukaryotic gene regulation, recombination, transcription and viral integration by altering the local chromatin structure and their dysregulation in disease manifestation
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Townson SM, Kang K, Lee AV, Oesterreich S. Novel role of the RET finger protein in estrogen receptor-mediated transcription in MCF-7 cells. Biochem Biophys Res Commun 2006; 349:540-8. [PMID: 16945332 PMCID: PMC1950156 DOI: 10.1016/j.bbrc.2006.08.063] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Accepted: 08/11/2006] [Indexed: 01/17/2023]
Abstract
The Scaffold attachment factor B1 (SAFB1) is an estrogen receptor (ESR1) repressor that has been proposed to inhibit breast tumorigenesis. To obtain insight into the functions of SAFB1 we utilized a yeast two-hybrid screen and identified the Ret finger protein (RFP) as interacting with the SAFB1 C-terminus. RFP is a member of the trimotif (TRIM) family of proteins, which we found widely expressed in a series of breast cancer cell lines. We confirmed the interaction between SAFB1 and RFP through in vitro (GST-pull-down) and in vivo (coimmunoprecipitations) assays. We hypothesized that SAFB1 functions as a scaffolding protein to recruit proteins such as RFP into proximity with ESR1. Consequently, we asked whether RFP would modulate ESR1 activity and we discovered that RFP was important for the ESR1-dependent expression of cyclin D1 (CCND1) and the progesterone receptor (PR), but not IRS1 or MYC. Although RFP did not interact with ESR1 directly, it does coimmunoprecipitate with ESR1, demonstrating that RFP is found within the same protein complex. Chromatin immunoprecipitation assays (ChIP) located RFP to the TFF1 promoter, a known ESR1-regulated gene. Taken together, our study provides further evidence that coactivation and corepression are integrally linked processes and that RFP is a component of an ESR1 regulatory complex.
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Affiliation(s)
- Steven M Townson
- Department of Human Genetics, Virginia Commonwealth University and Massey Cancer Center, Sanger Hall, Richmond, VA 23219, USA.
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45
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Didelot C, Schmitt E, Brunet M, Maingret L, Parcellier A, Garrido C. Heat shock proteins: endogenous modulators of apoptotic cell death. Handb Exp Pharmacol 2006:171-98. [PMID: 16610360 DOI: 10.1007/3-540-29717-0_8] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The highly conserved heat shock proteins (Hsps) accumulate in cells exposed to heat and a variety of other stressful stimuli. Hsps, that function mainly as molecular chaperones, allow cells to adapt to gradual changes in their environment and to survive in otherwise lethal conditions. The events of cell stress and cell death are linked and Hsps induced in response to stress appear to function at key regulatory points in the control of apoptosis. Hsps include anti-apoptotic and pro-apoptotic proteins that interact with a variety of cellular proteins involved in apoptosis. Their expression level can determine the fate of the cell in response to a death stimulus, and apoptosis-inhibitory Hsps, in particular Hsp27 and Hsp70, may participate in carcinogenesis. This review summarizes the apoptosis-regulatory function of Hsps.
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Affiliation(s)
- C Didelot
- Faculty of Medicine and Pharmacy, INSERM U-517, Dijon, France
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46
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Auboeuf D, Dowhan DH, Dutertre M, Martin N, Berget SM, O'Malley BW. A subset of nuclear receptor coregulators act as coupling proteins during synthesis and maturation of RNA transcripts. Mol Cell Biol 2005; 25:5307-16. [PMID: 15964789 PMCID: PMC1156981 DOI: 10.1128/mcb.25.13.5307-5316.2005] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Affiliation(s)
- Didier Auboeuf
- INSERM U685/AVENIR, Centre G. Hayem, Hôpital Saint Louis, Paris, France.
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47
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Ivanova M, Dobrzycka KM, Jiang S, Michaelis K, Meyer R, Kang K, Adkins B, Barski OA, Zubairy S, Divisova J, Lee AV, Oesterreich S. Scaffold attachment factor B1 functions in development, growth, and reproduction. Mol Cell Biol 2005; 25:2995-3006. [PMID: 15798188 PMCID: PMC1069606 DOI: 10.1128/mcb.25.8.2995-3006.2005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Scaffold attachment factor B1 (SAFB1) is a multifunctional protein that can bind both DNA and RNA and is involved in RNA processing and stress response. In addition, SAFB1 contains a transcriptional repression domain and can bind certain hormone receptors and repress their activity. To assess the role of SAFB1 in vivo, we generated SAFB1 mutant mice through targeted deletion in embryonic stem cells. While viable homozygous mutant (SAFB1-/-) mice were obtained, genotypic distribution indicated that homozygous deficiency resulted in both prenatal and neonatal lethality. Mice lacking SAFB1 exhibited dwarfism, as a result of in utero growth retardation, and had low serum insulin-like growth factor 1 (IGF1) levels. In agreement with the previous characterization of SAFB1 as a corepressor for hormone receptors, we found that SAFB1-/- mice displayed dramatic defects in the development and function of the reproductive system. Male SAFB1 null mice were infertile, apparently because of low circulating levels of testosterone. SAFB1-/- testes were small and showed progressive degeneration of the germinal epithelium, increased apoptosis of germ cells, and Leydig cell hyperplasia. SAFB-/- female mice were subfertile and showed progressive infertility, in part because of defects in oviductal transport and reduced numbers of follicles. Immortalized SAFB1-/- mouse embryonic fibroblasts showed cell-intrinsic defects including increased transcriptional estrogen receptor alpha activity and enhanced responsiveness to IGF1. Together, these in vivo findings establish a critical role for SAFB1 in development, growth regulation, and reproduction.
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Affiliation(s)
- Margarita Ivanova
- Department of Medicine, Baylor College of Medicine, Breast Center, One Baylor Plaza, Houston, TX 77030, USA
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Lee SA, Ndisang D, Patel C, Dennis JH, Faulkes DJ, D'Arrigo C, Samady L, Farooqui-Kabir S, Heads RJ, Latchman DS, Budhram-Mahadeo VS. Expression of the Brn-3b Transcription Factor Correlates with Expression of HSP-27 in Breast Cancer Biopsies and Is Required for Maximal Activation of the HSP-27 Promoter. Cancer Res 2005; 65:3072-80. [PMID: 15833836 DOI: 10.1158/0008-5472.can-04-2865] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In breast cancer, overexpression of the small heat shock protein, HSP-27, is associated with increased anchorage-independent growth, increased invasiveness, and resistance to chemotherapeutic drugs and is associated with poor prognosis and reduced disease-free survival. Therefore, factors that increase the expression of HSP-27 in breast cancer are likely to affect the prognosis and outcome of treatment. In this study, we show a strong correlation between elevated levels of the Brn-3b POU transcription factor and high levels of HSP-27 protein in manipulated MCF-7 breast cancer cells as well as in human breast biopsies. Conversely, HSP-27 is decreased on loss of Brn-3b. In cotransfection assays, Brn-3b can strongly transactivate the HSP-27 promoter, supporting a role for direct regulation of HSP-27 expression. Brn-3b also cooperates with the estrogen receptor (ER) to facilitate maximal stimulation of the HSP-27 promoter, with significantly enhanced activity of this promoter observed on coexpression of Brn-3b and ER compared with either alone. RNA interference and site-directed mutagenesis support the requirement for the Brn-3b binding site on the HSP-27 promoter, which facilitates maximal transactivation either alone or on interaction with the ER. Chromatin immunoprecipitation provides evidence for association of Brn-3b with the HSP-27 promoter in the intact cell. Thus, Brn-3b can, directly and indirectly (via interaction with the ER), activate HSP-27 expression, and this may represent one mechanism by which Brn-3b mediates its effects in breast cancer cells.
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Affiliation(s)
- Sonia A Lee
- Medical Molecular Biology Unit, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
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49
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Heldring N, Nilsson M, Buehrer B, Treuter E, Gustafsson JA. Identification of tamoxifen-induced coregulator interaction surfaces within the ligand-binding domain of estrogen receptors. Mol Cell Biol 2004; 24:3445-59. [PMID: 15060164 PMCID: PMC381632 DOI: 10.1128/mcb.24.8.3445-3459.2004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Tamoxifen is a selective estrogen receptor (ER) modulator that is clinically used as an antagonist to treat estrogen-dependent breast cancers but displays unwanted agonistic effects in other tissues. Previous studies on ERalpha have delineated a role of the N-terminal activation function AF-1 in mediating the agonistic effects of tamoxifen, while the mechanisms for how ERbeta mediates tamoxifen action remain to be elucidated. As peptides can be used to detect distinct receptor conformations and binding surfaces for coactivators and corepressors, we attempted in this study to identify previously unrecognized peptides that interact specifically with ERs in the presence of tamoxifen. We identified two distinct peptides among others that are highly selective for tamoxifen-bound ERalpha or ERbeta. Domain mapping and mutation analysis suggest that these peptides recognize a novel tamoxifen-induced binding surface within the C-terminal ligand-binding domain that is distinct from the agonist-induced AF-2 surface. Peptide expression specifically inhibited transcriptional ER activity in response to tamoxifen, presumably by preventing the binding of endogenous coactivators. Moreover, tamoxifen-responsive and ER subtype-selective coactivators were engineered by replacing the LXXLL motifs in the coactivator TIF2 with either of the two peptides. Finally, our results indicate that related coactivators may act via the novel tamoxifen-induced binding surface, referred to as AF-T, allowing us to propose a revised model of tamoxifen agonism.
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Affiliation(s)
- Nina Heldring
- Department of Biosciences at Novum, Karolinska Institutet, S-14157 Huddinge, Sweden
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50
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Townson SM, Kang K, Lee AV, Oesterreich S. Structure-function analysis of the estrogen receptor alpha corepressor scaffold attachment factor-B1: identification of a potent transcriptional repression domain. J Biol Chem 2004; 279:26074-81. [PMID: 15066997 DOI: 10.1074/jbc.m313726200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Scaffold attachment factor-B1 (SAFB1) is a nuclear matrix protein that has been proposed to couple chromatin structure, transcription, and RNA processing. We have previously shown that SAFB1 can repress estrogen receptor (ERalpha)-mediated transactivation. Here we present a structure-function study showing that transactivation is mediated via an intrinsic and transferable C-terminal repression domain (RD). A similar C-terminal RD was found in the family member SAFB2. Removal of the RD from SAFB1 resulted in a dominant-negative SAFB1 protein that increased ligand-dependent and -independent ERalpha activity. SAFB1RD-mediated repression was partly blocked by histone deacetylase inhibitors; however, no histone deacetylase inhibitors were identified in a yeast two-hybrid screen using the RD as bait. Instead, SAFB1RD was found to interact with TAFII68, a member of the basal transcription machinery. We propose a model in which SAFB1 represses ERalpha activity via indirect association with histone deacetylation and interaction with the basal transcription machinery.
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Affiliation(s)
- Steven M Townson
- Departments of Medicine, The Breast Center, Baylor College of Medicine and Methodist Hospital, Houston, Texas 77030, USA
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