1
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Wang M, Pan B, Hu Y, Gao J, Hou L, Yu Z, Li M, Zhao Z. STIL facilitates the development and malignant progression of triple-negative breast cancer through activation of Fanconi anemia pathway via interacting with KLF16. Transl Oncol 2024; 46:102010. [PMID: 38823260 PMCID: PMC11177054 DOI: 10.1016/j.tranon.2024.102010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 05/08/2024] [Accepted: 05/25/2024] [Indexed: 06/03/2024] Open
Abstract
BACKGROUND STIL is an important cell cycle-regulating protein specifically recruited to the mitotic centrosome to promote the replication of centrioles in dividing cells. However, the potential role of STIL in the regulation of the biological functions of triple-negative breast cancer remains still unclear. METHODS We screened for differentially expressed STIL in the Cancer Genome Atlas database. The expression of STIL protein in 10 pairs of breast cancer tissues and adjacent normal tissues was further assessed by western blotting. Functionally, the knockdown and overexpression of STIL have been used to explore the effects of STIL on breast cancer cell proliferation, migration, and invasion. Mechanistically, RNA-seq, dual-luciferase reporter assay, chromatin immunoprecipitation assay, mass spectrometry, immunoprecipitation assay, and DNA pull-down assay were performed. RESULTS Breast cancer tissues and cells have higher STIL expression than normal tissues and cells. STIL knockdown impairs breast cancer cell growth, migration, and invasion, whereas STIL overexpression accelerates these processes. STIL promotes breast cancer progression by regulating FANCD2 expression, and exploration of its molecular mechanism demonstrated that STIL interacts with KLF16 to regulate the expression of FANCD2. CONCLUSIONS Collectively, our findings identified STIL as a critical promoter of breast cancer progression that interacts with KLF16 to regulate Fanconi anemia pathway protein FANCD2. In summary, STIL is a potential novel biomarker and therapeutic target for breast cancer.
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Affiliation(s)
- Meiling Wang
- Department of Breast Surgery & Department of Oncology, The Second Hospital of Dalian Medical University, Dalian, 116023 China
| | - Bo Pan
- Department of Breast Surgery & Department of Oncology, The Second Hospital of Dalian Medical University, Dalian, 116023 China
| | - Ye Hu
- Department of Breast Surgery & Department of Oncology, The Second Hospital of Dalian Medical University, Dalian, 116023 China
| | - Jiyue Gao
- Department of Breast Surgery & Department of Oncology, The Second Hospital of Dalian Medical University, Dalian, 116023 China
| | - Lu Hou
- Department of Breast Surgery & Department of Oncology, The Second Hospital of Dalian Medical University, Dalian, 116023 China
| | - Zhenlong Yu
- College of Pharmacy, Dalian Medical University, Dalian, China.
| | - Man Li
- Department of Breast Surgery & Department of Oncology, The Second Hospital of Dalian Medical University, Dalian, 116023 China.
| | - Zuowei Zhao
- Department of Breast Surgery & Department of Oncology, The Second Hospital of Dalian Medical University, Dalian, 116023 China.
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2
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Ilchuk LA, Kubekina MV, Okulova YD, Silaeva YY, Tatarskiy VV, Filatov MA, Bruter AV. Genetically Engineered Mice Unveil In Vivo Roles of the Mediator Complex. Int J Mol Sci 2023; 24:ijms24119330. [PMID: 37298278 DOI: 10.3390/ijms24119330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/16/2023] [Accepted: 05/24/2023] [Indexed: 06/12/2023] Open
Abstract
The Mediator complex is a multi-subunit protein complex which plays a significant role in the regulation of eukaryotic gene transcription. It provides a platform for the interaction of transcriptional factors and RNA polymerase II, thus coupling external and internal stimuli with transcriptional programs. Molecular mechanisms underlying Mediator functioning are intensively studied, although most often using simple models such as tumor cell lines and yeast. Transgenic mouse models are required to study the role of Mediator components in physiological processes, disease, and development. As constitutive knockouts of most of the Mediator protein coding genes are embryonically lethal, conditional knockouts and corresponding activator strains are needed for these studies. Recently, they have become more easily available with the development of modern genetic engineering techniques. Here, we review existing mouse models for studying the Mediator, and data obtained in corresponding experiments.
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Affiliation(s)
- Leonid A Ilchuk
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Marina V Kubekina
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Yulia D Okulova
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Yulia Yu Silaeva
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, 119334 Moscow, Russia
| | - Victor V Tatarskiy
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, 119334 Moscow, Russia
| | - Maxim A Filatov
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Alexandra V Bruter
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia
- Federal State Budgetary Institution "N.N. Blokhin National Medical Research Center of Oncology", Ministry of Health of the Russian Federation, Kashirskoe Sh. 24, 115478 Moscow, Russia
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3
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Zhou Z, Yan H, Kim MS, Shim WB. Distinct Function of Mediator Subunits in Fungal Development, Stress Response, and Secondary Metabolism in Maize Pathogen Fusarium verticillioides. PHYTOPATHOLOGY 2022; 112:1730-1738. [PMID: 35271780 DOI: 10.1094/phyto-12-21-0495-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Mediator is a nucleus-localized, multisubunit protein complex highly conserved across eukaryotes. It interacts with RNA polymerase II transcription machinery as well as various transcription factors to regulate gene expression. However, systematic characterization of the Mediator complex has not been performed in filamentous fungi. In our study, the goal was to investigate key biological functions of Mediator subunits in a mycotoxigenic plant pathogen Fusarium verticillioides. Although there is some level of divergence in the constituent subunits, the overall structure was conserved between Saccharomyces cerevisiae and F. verticillioides. We generated 11 Mediator subunit deletion mutants and characterized vegetative growth, conidia formation, environmental stress response, carbon and fatty acid use, virulence, and fumonisin B1 (FB1) biosynthesis. Each Mediator subunit deletion mutant showed deficiencies in at least three of the phenotypes tested, suggesting that each subunit has different principal functions in F. verticillioides development, metabolism, and virulence. The deletion of FvMed1 led to increased FB1 production, and we confirmed that FvMed1 is transported from the nucleus to the cytoplasm under fumonisin-producing conditions. Taken together, our study characterized various important functional roles for Mediator subunits in F. verticillioides and suggests that select subunits can perform unique cytoplasmic functions independent of the core Mediator in fungal nucleus.
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Affiliation(s)
- Zehua Zhou
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, U.S.A
- Hunan Agricultural University, College of Plant Protection & Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Plant Pests, Furong District, Changsha, Hunan 410128, China
| | - Huijuan Yan
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, U.S.A
- Department of Microbiology and Immunology, University of California at San Francisco, San Francisco, CA 94143, U.S.A
| | - Man S Kim
- Clinical Research Institute, College of Medicine, Kyung Hee University Hospital at Gangdong, Seoul, South Korea
| | - Won Bo Shim
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, U.S.A
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Yang Y, Xiao Q, Yin J, Li C, Yu D, He Y, Yang Z, Wang G. Med23 supports angiogenesis and maintains vascular integrity through negative regulation of angiopoietin2 expression. Commun Biol 2022; 5:374. [PMID: 35440711 PMCID: PMC9019027 DOI: 10.1038/s42003-022-03332-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 03/30/2022] [Indexed: 01/17/2023] Open
Abstract
The mammalian Mediator complex consists of over 30 subunits and functions as a transcriptional hub integrating signaling for tissue-specific gene expression. Although the role of the Mediator complex in transcription has been extensively investigated, the functions of distinct Mediator subunits in development are not well understood. Here, we dissected the role of the Mediator subunit Med23 in mouse cardiovascular development. Endothelial-specific Med23 deletion caused embryonic lethality before embryonic day 13.5 (E13.5). The mutant embryos exhibited intracranial hemorrhage and diminished angiogenesis with dilated blood vessels in the head region, where the expression of Med23 was abundant at E10.5. Med23 deficiency impaired vasculogenesis in the head region and impeded retinal angiogenesis. Knocking down Med23 in human umbilical vein endothelial cells (HUVECs) resulted in angiogenic defects, recapitulating the vascular defects in Med23-mutant mice in a cell-autonomous manner. RNA sequencing in HUVECs indicated that Med23 deficiency resulted in the interruption of angiogenesis and the upregulation of angiopoietin2 (Ang2), an inducing factor for vascular network instability. Inhibition of Ang2 partially rescued angiogenic sprouting and lumen dilation defects in tube formation assays. Collectively, our findings demonstrate that Med23 promotes angiogenesis and maintains vascular integrity, in part by suppressing Ang2 signaling.
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Affiliation(s)
- Yenan Yang
- State Key Laboratory of Genetic Engineering, School of Life Sciences and Zhongshan Hospital, Fudan University, Shanghai, 200438, China
| | - Qi Xiao
- The Ministry of Education Key Laboratory of Model Animal for Disease Study, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, 210061, China
| | - Jingwen Yin
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Chonghui Li
- State Key Laboratory of Cell Biology, Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 200031, China
| | - Decai Yu
- Department of Hepatobiliary Surgery, the Affiliated Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Yulong He
- Laboratory of Vascular and Cancer Biology, Cyrus Tang Hematology Center, Jiangsu Institute of Hematology, the First Affiliated Hospital, Soochow University, Suzhou, China
| | - Zhongzhou Yang
- Department of Cardiology, State Key Laboratory of Pharmaceutical Biotechnology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Medical School of Nanjing University, Nanjing, 210093, China.
| | - Gang Wang
- State Key Laboratory of Genetic Engineering, School of Life Sciences and Zhongshan Hospital, Fudan University, Shanghai, 200438, China.
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5
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The Mediator kinase module: an interface between cell signaling and transcription. Trends Biochem Sci 2022; 47:314-327. [DOI: 10.1016/j.tibs.2022.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 01/11/2022] [Accepted: 01/17/2022] [Indexed: 12/14/2022]
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6
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Thiel G, Backes TM, Guethlein LA, Rössler OG. Critical Protein-Protein Interactions Determine the Biological Activity of Elk-1, a Master Regulator of Stimulus-Induced Gene Transcription. Molecules 2021; 26:molecules26206125. [PMID: 34684708 PMCID: PMC8541449 DOI: 10.3390/molecules26206125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/03/2021] [Accepted: 10/05/2021] [Indexed: 12/22/2022] Open
Abstract
Elk-1 is a transcription factor that binds together with a dimer of the serum response factor (SRF) to the serum-response element (SRE), a genetic element that connects cellular stimulation with gene transcription. Elk-1 plays an important role in the regulation of cellular proliferation and apoptosis, thymocyte development, glucose homeostasis and brain function. The biological function of Elk-1 relies essentially on the interaction with other proteins. Elk-1 binds to SRF and generates a functional ternary complex that is required to activate SRE-mediated gene transcription. Elk-1 is kept in an inactive state under basal conditions via binding of a SUMO-histone deacetylase complex. Phosphorylation by extracellular signal-regulated protein kinase, c-Jun N-terminal protein kinase or p38 upregulates the transcriptional activity of Elk-1, mediated by binding to the mediator of RNA polymerase II transcription (Mediator) and the transcriptional coactivator p300. Strong and extended phosphorylation of Elk-1 attenuates Mediator and p300 recruitment and allows the binding of the mSin3A-histone deacetylase corepressor complex. The subsequent dephosphorylation of Elk-1, catalyzed by the protein phosphatase calcineurin, facilitates the re-SUMOylation of Elk-1, transforming Elk-1 back to a transcriptionally inactive state. Thus, numerous protein–protein interactions control the activation cycle of Elk-1 and are essential for its biological function.
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Affiliation(s)
- Gerald Thiel
- Department of Medical Biochemistry and Molecular Biology, Saarland University Medical Faculty, D-66421 Homburg, Germany; (T.M.B.); (O.G.R.)
- Correspondence: ; Tel.: +49-6841-1626506; Fax: +49-6841-1626500
| | - Tobias M. Backes
- Department of Medical Biochemistry and Molecular Biology, Saarland University Medical Faculty, D-66421 Homburg, Germany; (T.M.B.); (O.G.R.)
| | - Lisbeth A. Guethlein
- Department of Structural Biology and Department of Microbiology & Immunology, School of Medicine, Stanford University, Stanford, CA 94305, USA;
| | - Oliver G. Rössler
- Department of Medical Biochemistry and Molecular Biology, Saarland University Medical Faculty, D-66421 Homburg, Germany; (T.M.B.); (O.G.R.)
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7
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Sun X, Yin JW, Liang Y, Li C, Gao P, Yu Y, Wang G. Mediator Med23 deficiency in smooth muscle cells prevents neointima formation after arterial injury. Cell Discov 2021; 7:59. [PMID: 34341334 PMCID: PMC8329203 DOI: 10.1038/s41421-021-00285-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 05/18/2021] [Indexed: 11/09/2022] Open
Affiliation(s)
- Xiaoli Sun
- State Key Laboratory of Genetic Engineering, School of Life Sciences and Zhongshan Hospital, Fudan University, Shanghai, China
- Institutes of Biomedical Sciences, Shanghai Xuhui District Central Hospital, Zhongshan Xuhui Hospital, Fudan University, Shanghai, China
| | - Jing-Wen Yin
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Yan Liang
- Department of Medicine, University of California-San Diego, La Jolla, CA, USA
| | - Chonghui Li
- State Key Laboratory of Cell Biology, Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Pingjin Gao
- International Peace Maternity and Children Hospital of China Welfare Institution, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ying Yu
- Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Gang Wang
- State Key Laboratory of Genetic Engineering, School of Life Sciences and Zhongshan Hospital, Fudan University, Shanghai, China.
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8
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Diao C, Guo P, Yang W, Sun Y, Liao Y, Yan Y, Zhao A, Cai X, Hao J, Hu S, Yu W, Chen M, Wang R, Li W, Zuo Y, Pan J, Hua C, Lu X, Fan W, Zheng Z, Deng W, Luo G, Guo W. SPT6 recruits SND1 to co-activate human telomerase reverse transcriptase to promote colon cancer progression. Mol Oncol 2021; 15:1180-1202. [PMID: 33305480 PMCID: PMC8024721 DOI: 10.1002/1878-0261.12878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 10/06/2020] [Accepted: 12/09/2020] [Indexed: 12/24/2022] Open
Abstract
Human telomerase reverse transcriptase (hTERT) plays an extremely important role in cancer initiation and development, including colorectal cancer (CRC). However, the precise upstream regulatory mechanisms of hTERT in different cancer types remain poorly understood. Here, we uncovered the candidate transcriptional factor of hTERT in CRC and explored its role and the corresponding molecular mechanisms in regulating hTERT expression and CRC survival with an aim of developing mechanism-based combinational targeting therapy. The possible binding proteins at the hTERT promoter were uncovered using pull-down/mass spectrometry analysis. The regulation of SPT6 on hTERT expression and CRC survival was evaluated in human CRC cell lines and mouse models. Mechanistic studies focusing on the synergy between SPT6 and staphylococcal nuclease and Tudor domain containing 1 (SND1) in controlling hTERT expression and CRC progression were conducted also in the above two levels. The expression correlation and clinical significance of SPT6, SND1, and hTERT were investigated in tumor tissues from murine models and patients with CRC in situ. SPT6 was identified as a possible transcriptional factor to bind to the hTERT promoter. SPT6 knockdown decreased the activity of hTERT promoter, downregulated the protein expression level of hTERT, suppressed proliferation, invasion, and stem-like properties, promoted apoptosis induction, and enhanced chemotherapeutic drug sensitivity in vitro. SPT6 silencing also led to the delay of tumor growth and metastasis in mice carrying xenografts of human-derived colon cancer cells. Mechanistically, SND1 interacted with SPT6 to co-control hTERT expression and CRC cell proliferation, stemness, and growth in vitro and in vivo. SPT6, SND1, and hTERT were highly expressed simultaneously in CRC tissues, both from the murine model and patients with CRC in situ, and pairwise expression among these three factors showed a significant positive correlation. In brief, our research demonstrated that SPT6 synergized with SND1 to promote CRC development by targeting hTERT and put forward that inhibiting the SPT6-SND1-hTERT axis may create a therapeutic vulnerability in CRC.
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Affiliation(s)
- Chaoliang Diao
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
| | - Ping Guo
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
| | - Wenjing Yang
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
| | - Yao Sun
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
| | - Yina Liao
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
| | - Yue Yan
- State Key Laboratory of Oncology in South ChinaCollaborative Innovation Center of Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Anshi Zhao
- State Key Laboratory of Oncology in South ChinaCollaborative Innovation Center of Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Xin Cai
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
| | - Jiaojiao Hao
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
| | - Sheng Hu
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
| | - Wendan Yu
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
| | - Manyu Chen
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
| | - Ruozhu Wang
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
| | - Wenyang Li
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
| | - Yan Zuo
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
| | - Jinjin Pan
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
| | - Chunyu Hua
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
| | - Xiaona Lu
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
| | - Wenhua Fan
- State Key Laboratory of Oncology in South ChinaCollaborative Innovation Center of Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Zongheng Zheng
- The Third Affiliated HospitalSun Yat‐sen UniversityGuangzhouChina
| | - Wuguo Deng
- State Key Laboratory of Oncology in South ChinaCollaborative Innovation Center of Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Guangyu Luo
- State Key Laboratory of Oncology in South ChinaCollaborative Innovation Center of Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Wei Guo
- Institute of Cancer Stem Cells and the First Affiliated HospitalDalian Medical UniversityChina
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9
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Wu Y, Peng M, Chen J, Suo J, Zou S, Xu Y, Wilkie AOM, Zou W, Mu X, Wang S. A custom-designed panel sequencing study in 201 Chinese patients with craniosynostosis revealed novel variants and distinct mutation spectra. J Genet Genomics 2020; 48:167-171. [PMID: 33547006 DOI: 10.1016/j.jgg.2020.11.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/05/2020] [Accepted: 11/13/2020] [Indexed: 01/18/2023]
Affiliation(s)
- Yingzhi Wu
- Department of Plastic Surgery, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Meifang Peng
- State Key Laboratory of Genetic Engineering at School of Life Sciences, Fudan University, Shanghai 200011, China; CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jieyi Chen
- State Key Laboratory of Genetic Engineering at School of Life Sciences, Fudan University, Shanghai 200011, China; CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jinlong Suo
- The State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Sihai Zou
- Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Chongqing Medical University, Chongqing 401147, China; Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing 401147, China
| | - Yanqing Xu
- Forest Ridge School of the Sacred Heart, Bellevue, WA 98006, USA
| | - Andrew O M Wilkie
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Weiguo Zou
- The State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiongzheng Mu
- Department of Plastic Surgery, Huashan Hospital, Fudan University, Shanghai 200040, China.
| | - Sijia Wang
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China; Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China.
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10
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Dash S, Bhatt S, Sandell LL, Seidel CW, Ahn Y, Krumlauf RE, Trainor PA. The Mediator Subunit, Med23 Is Required for Embryonic Survival and Regulation of Canonical WNT Signaling During Cranial Ganglia Development. Front Physiol 2020; 11:531933. [PMID: 33192541 PMCID: PMC7642510 DOI: 10.3389/fphys.2020.531933] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 09/16/2020] [Indexed: 11/13/2022] Open
Abstract
Development of the vertebrate head is a complex and dynamic process, which requires integration of all three germ layers and their derivatives. Of special importance are ectoderm-derived cells that form the cranial placodes, which then differentiate into the cranial ganglia and sensory organs. Critical to a fully functioning head, defects in cranial placode and sensory organ development can result in congenital craniofacial anomalies. In a forward genetic screen aimed at identifying novel regulators of craniofacial development, we discovered an embryonically lethal mouse mutant, snouty, which exhibits malformation of the facial prominences, cranial nerves and vasculature. The snouty mutation was mapped to a single nucleotide change in a ubiquitously expressed gene, Med23, which encodes a subunit of the global transcription co-factor complex, Mediator. Phenotypic analyses revealed that the craniofacial anomalies, particularly of the cranial ganglia, were caused by a failure in the proper specification of cranial placode neuronal precursors. Molecular analyses determined that defects in cranial placode neuronal differentiation in Med23 sn/sn mutants were associated with elevated WNT/β-catenin signaling, which can be partially rescued through combined Lrp6 and Wise loss-of-function. Our work therefore reveals a surprisingly tissue specific role for the ubiquitously expressed mediator complex protein Med23 in placode differentiation during cranial ganglia development. This highlights the importance of coupling general transcription to the regulation of WNT signaling during embryogenesis.
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Affiliation(s)
- Soma Dash
- Stowers Institute for Medical Research, Kansas City, MO, United States
| | - Shachi Bhatt
- Stowers Institute for Medical Research, Kansas City, MO, United States.,Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Lisa L Sandell
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY, United States
| | | | - Youngwook Ahn
- Stowers Institute for Medical Research, Kansas City, MO, United States
| | - Robb E Krumlauf
- Stowers Institute for Medical Research, Kansas City, MO, United States.,Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Paul A Trainor
- Stowers Institute for Medical Research, Kansas City, MO, United States.,Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, United States
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Abstract
Regeneration is the process by which organisms replace lost or damaged tissue, and regenerative capacity can vary greatly among species, tissues and life stages. Tissue regeneration shares certain hallmarks of embryonic development, in that lineage-specific factors can be repurposed upon injury to initiate morphogenesis; however, many differences exist between regeneration and embryogenesis. Recent studies of regenerating tissues in laboratory model organisms - such as acoel worms, frogs, fish and mice - have revealed that chromatin structure, dedicated enhancers and transcriptional networks are regulated in a context-specific manner to control key gene expression programmes. A deeper mechanistic understanding of the gene regulatory networks of regeneration pathways might ultimately enable their targeted reactivation as a means to treat human injuries and degenerative diseases. In this Review, we consider the regeneration of body parts across a range of tissues and species to explore common themes and potentially exploitable elements.
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Affiliation(s)
- Joseph A Goldman
- Department of Biological Chemistry and Pharmacology, Ohio State University, Columbus, OH, USA.
| | - Kenneth D Poss
- Regeneration Next, Duke University, Durham, NC, USA.
- Department of Cell Biology, Duke University Medical Center, Durham, NC, USA.
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12
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Hiebert CW, Moscou MJ, Hewitt T, Steuernagel B, Hernández-Pinzón I, Green P, Pujol V, Zhang P, Rouse MN, Jin Y, McIntosh RA, Upadhyaya N, Zhang J, Bhavani S, Vrána J, Karafiátová M, Huang L, Fetch T, Doležel J, Wulff BBH, Lagudah E, Spielmeyer W. Stem rust resistance in wheat is suppressed by a subunit of the mediator complex. Nat Commun 2020; 11:1123. [PMID: 32111840 PMCID: PMC7048732 DOI: 10.1038/s41467-020-14937-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 02/11/2020] [Indexed: 11/18/2022] Open
Abstract
Stem rust is an important disease of wheat that can be controlled using resistance genes. The gene SuSr-D1 identified in cultivar ‘Canthatch’ suppresses stem rust resistance. SuSr-D1 mutants are resistant to several races of stem rust that are virulent on wild-type plants. Here we identify SuSr-D1 by sequencing flow-sorted chromosomes, mutagenesis, and map-based cloning. The gene encodes Med15, a subunit of the Mediator Complex, a conserved protein complex in eukaryotes that regulates expression of protein-coding genes. Nonsense mutations in Med15b.D result in expression of stem rust resistance. Time-course RNAseq analysis show a significant reduction or complete loss of differential gene expression at 24 h post inoculation in med15b.D mutants, suggesting that transcriptional reprogramming at this time point is not required for immunity to stem rust. Suppression is a common phenomenon and this study provides novel insight into suppression of rust resistance in wheat. Stem rust is an important disease of wheat and resistance present in some cultivars can be suppressed by the SuSr-D1 locus. Here the authors show that SuSr-D1 encodes a subunit of the Mediator Complex and that nonsense mutations are sufficient to abolish suppression and confer stem rust resistance.
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Affiliation(s)
- Colin W Hiebert
- Agriculture and Agri-Food Canada, Morden Research and Development Centre, 101 Route 100, Morden, MB, R6M 1Y5, Canada.
| | - Matthew J Moscou
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, NR4 7UK, UK.
| | - Tim Hewitt
- Plant Breeding Institute Cobbitty, University of Sydney, Private Bag 4011, Narellan, NSW, 2567, Australia.,CSIRO Agriculture & Food, GPO Box 1700, Canberra, ACT, 2601, Australia
| | | | - Inma Hernández-Pinzón
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, NR4 7UK, UK
| | - Phon Green
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, NR4 7UK, UK
| | - Vincent Pujol
- Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
| | - Peng Zhang
- Plant Breeding Institute Cobbitty, University of Sydney, Private Bag 4011, Narellan, NSW, 2567, Australia
| | - Matthew N Rouse
- USDA-ARS, Cereal Disease Laboratory, University of Minnesota, St. Paul, MN, 55108, USA
| | - Yue Jin
- USDA-ARS, Cereal Disease Laboratory, University of Minnesota, St. Paul, MN, 55108, USA
| | - Robert A McIntosh
- Plant Breeding Institute Cobbitty, University of Sydney, Private Bag 4011, Narellan, NSW, 2567, Australia
| | | | - Jianping Zhang
- CSIRO Agriculture & Food, GPO Box 1700, Canberra, ACT, 2601, Australia
| | - Sridhar Bhavani
- CIMMYT, ICRAF House, United Nations Avenue, Gigiri, Village Market, Nairobi, 00621, Kenya
| | - Jan Vrána
- Institute of Experimental Botany, Czech Academy of Sciences, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů 31, 779 00, Olomouc, Czech Republic
| | - Miroslava Karafiátová
- Institute of Experimental Botany, Czech Academy of Sciences, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů 31, 779 00, Olomouc, Czech Republic
| | - Li Huang
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT, 59717, USA
| | - Tom Fetch
- Agriculture and Agri-Food Canada, Morden Research and Development Centre, 101 Route 100, Morden, MB, R6M 1Y5, Canada
| | - Jaroslav Doležel
- Institute of Experimental Botany, Czech Academy of Sciences, Centre of the Region Haná for Biotechnological and Agricultural Research, Šlechtitelů 31, 779 00, Olomouc, Czech Republic
| | | | - Evans Lagudah
- CSIRO Agriculture & Food, GPO Box 1700, Canberra, ACT, 2601, Australia.
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13
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Napoli C, Schiano C, Soricelli A. Increasing evidence of pathogenic role of the Mediator (MED) complex in the development of cardiovascular diseases. Biochimie 2019; 165:1-8. [PMID: 31255603 DOI: 10.1016/j.biochi.2019.06.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 06/24/2019] [Indexed: 12/20/2022]
Abstract
Cardiovascular diseases (CVDs) are the first cause of death in the World. Mediator (MED) is an evolutionarily conserved protein complex, which mediates distinct protein-protein interactions. Pathogenic events in MED subunit have been associated with human diseases. Novel increasing evidence showed that missense mutations in MED13L gene are associated with transposition of great arteries while MED12, MED13, MED15, and MED30, have been correlated with heart development. Moreover, MED23 and MED25 have been associated with heart malformations in humans. Relevantly, MED1, MED13, MED14, MED15, MED23, MED25, and CDK8, were found modify glucose and/or lipid metabolism. Indeed, MED1, MED15, MED25, and CDK8 interact in the PPAR- and SREBP-mediated signaling pathways. MED1, MED14 and MED23 are involved in adipocyte differentiation, whereas MED23 mediates smooth muscle cell differentiation. MED12, MED19, MED23, and MED30 regulate endothelial differentiation by alternative splicing mechanism. Thus, MEDs have a central role in early pathogenic events involved in CVDs representing novel targets for clinical prevention and therapeutic approaches.
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Affiliation(s)
- C Napoli
- University Department of Advanced Medical and Surgical Sciences, Clinical Department of Internal Medicine and Specialistic Units, University of Campania "L. Vanvitelli", 80138, Naples, Italy
| | | | - A Soricelli
- IRCCS SDN, 80143, Naples, Italy; Department of Motor Sciences and Healthiness, University of Naples Parthenope, 80134, Naples, Italy
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14
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Huang J, Sun Y, Orduna AR, Jetter R, Li X. The Mediator kinase module serves as a positive regulator of salicylic acid accumulation and systemic acquired resistance. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:842-852. [PMID: 30739357 DOI: 10.1111/tpj.14278] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/30/2019] [Accepted: 01/31/2019] [Indexed: 05/20/2023]
Abstract
In plants, the calmodulin-binding transcription activators (CAMTAs) are required for transcriptional regulation of abiotic and biotic stress responses. Among them, CAMTA3 in Arabidopsis has been intensively studied and shown to function redundantly with CAMTA1 and CAMTA2 to negatively regulate plant immunity. The camta1/2/3 triple mutant accordingly exhibits severe dwarfism due to autoimmunity. Here, through a suppressor screen using camta1/2/3 triple mutant, we found that a mutation in Cyclin-Dependent Kinase 8 (CDK8) partially suppresses the dwarfism and constitutive resistance phenotypes of camta1/2/3. CDK8 positively regulates steady-state salicylic acid (SA) levels and systemic required resistance (SAR). The expression of SA biosynthesis genes such as ICS1 and EDS5 is down-regulated in cdk8 mutants under uninfected conditions, suggesting that CDK8 contributes to the transcriptional regulation of these SA pathway genes. Knocking out another Mediator kinase module member MED12 yielded similar defects including decreased steady-state SA level and compromised SAR, suggesting that the whole Mediator kinase module contributes to the transcriptional regulation of SA levels and SAR.
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Affiliation(s)
- Jianhua Huang
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
- Department of Botany, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Yulin Sun
- Department of Botany, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Alberto R Orduna
- Department of Chemistry, University of British Columbia, Vancouver, BC, Canada, V6T 1Z1
| | - Reinhard Jetter
- Department of Botany, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Xin Li
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
- Department of Botany, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
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15
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Sierecki E. The Mediator complex and the role of protein-protein interactions in the gene regulation machinery. Semin Cell Dev Biol 2018; 99:20-30. [PMID: 30278226 DOI: 10.1016/j.semcdb.2018.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 08/13/2018] [Accepted: 08/13/2018] [Indexed: 12/11/2022]
Abstract
At the core of gene regulation, a complex network of dynamic interactions between proteins, DNA and RNA has to be integrated in order to generate a binary biological output. Large protein complexes, called adaptors, transfer information from the transcription factors to the transcription machinery [1,2]. Here we focus on Mediator, one of the largest adaptor proteins in humans [3]. Assembled from 30 different subunits, this system provides extraordinary illustrations for the various roles played by protein-protein interactions. Recruitment of new subunits during evolution is an adaptive mechanism to the growing complexity of the organism. Integration of information happens at multiple scales, with allosteric effects at the level of individual subunits resulting in large conformational changes. Mediator is also rich in disordered regions that increase the potential for interactions by presenting a malleable surface to its environment. Potentially, 3000 transcription factors can interact with Mediator and so understanding the molecular mechanisms that support the processing of this overload of information is one of the great challenges in molecular biology.
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Affiliation(s)
- Emma Sierecki
- EMBL Australia Node in Single Molecule Science, and School of Medical Sciences, Faculty of Medecine, The University of New South Wales, Sydney, Australia.
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16
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Adenovirus E1A Activation Domain Regulates H3 Acetylation Affecting Varied Steps in Transcription at Different Viral Promoters. J Virol 2018; 92:JVI.00805-18. [PMID: 29976669 PMCID: PMC6146688 DOI: 10.1128/jvi.00805-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 06/26/2018] [Indexed: 01/06/2023] Open
Abstract
Despite a wealth of data associating promoter and enhancer region histone N-terminal tail lysine acetylation with transcriptional activity, there are relatively few examples of studies that establish causation between these histone posttranslational modifications and transcription. While hypoacetylation of histone H3 lysines 18 and 27 is associated with repression, the step(s) in the overall process of transcription that is blocked at a hypoacetylated promoter is not clearly established in most instances. Studies presented here confirm that the adenovirus 2 large E1A protein activation domain interacts with p300, as reported previously (P. Pelka, J. N. G. Ablack, J. Torchia, A. S. Turnell, R. J. A. Grand, J. S. Mymryk, Nucleic Acids Res 37:1095–1106, 2009, https://doi.org/10.1093/nar/gkn1057), and that the resulting acetylation of H3K18/27 affects varied steps in transcription at different viral promoters. How histone acetylation promotes transcription is not clearly understood. Here, we confirm an interaction between p300 and the adenovirus 2 large E1A activation domain (AD) and map the interacting regions in E1A by observing colocalization at an integrated lacO array of fusions of LacI-mCherry to E1A fragments with YFP-p300. Viruses with mutations in E1A subdomains were constructed and analyzed for kinetics of early viral RNA expression and association of acetylated H3K9, K18, K27, TBP, and RNA polymerase II (Pol II) across the viral genome. The results indicate that this E1A interaction with p300 is required for H3K18 and H3K27 acetylation at the E2early, E3, and E4 promoters and is required for TBP and Pol II association with the E2early promoter. In contrast, H3K18/27 acetylation was not required for TBP and Pol II association with the E3 and E4 promoters but was required for E4 transcription at a step subsequent to Pol II preinitiation complex assembly. IMPORTANCE Despite a wealth of data associating promoter and enhancer region histone N-terminal tail lysine acetylation with transcriptional activity, there are relatively few examples of studies that establish causation between these histone posttranslational modifications and transcription. While hypoacetylation of histone H3 lysines 18 and 27 is associated with repression, the step(s) in the overall process of transcription that is blocked at a hypoacetylated promoter is not clearly established in most instances. Studies presented here confirm that the adenovirus 2 large E1A protein activation domain interacts with p300, as reported previously (P. Pelka, J. N. G. Ablack, J. Torchia, A. S. Turnell, R. J. A. Grand, J. S. Mymryk, Nucleic Acids Res 37:1095–1106, 2009, https://doi.org/10.1093/nar/gkn1057), and that the resulting acetylation of H3K18/27 affects varied steps in transcription at different viral promoters.
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17
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Enuka Y, Feldman ME, Chowdhury A, Srivastava S, Lindzen M, Sas-Chen A, Massart R, Cheishvili D, Suderman MJ, Zaltsman Y, Mazza CA, Shukla K, Körner C, Furth N, Lauriola M, Oren M, Wiemann S, Szyf M, Yarden Y. Epigenetic mechanisms underlie the crosstalk between growth factors and a steroid hormone. Nucleic Acids Res 2018; 45:12681-12699. [PMID: 29036586 PMCID: PMC5727445 DOI: 10.1093/nar/gkx865] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Accepted: 09/19/2017] [Indexed: 12/13/2022] Open
Abstract
Crosstalk between growth factors (GFs) and steroid hormones recurs in embryogenesis and is co-opted in pathology, but underlying mechanisms remain elusive. Our data from mammary cells imply that the crosstalk between the epidermal GF and glucocorticoids (GCs) involves transcription factors like p53 and NF-κB, along with reduced pausing and traveling of RNA polymerase II (RNAPII) at both promoters and bodies of GF-inducible genes. Essentially, GCs inhibit positive feedback loops activated by GFs and stimulate the reciprocal inhibitory loops. As expected, no alterations in DNA methylation accompany the transcriptional events instigated by either stimulus, but forced demethylation of regulatory regions broadened the repertoire of GF-inducible genes. We report that enhancers, like some promoters, are poised for activation by GFs and GCs. In addition, within the cooperative interface of the crosstalk, GFs enhance binding of the GC receptor to DNA and, in synergy with GCs, promote productive RNAPII elongation. Reciprocally, within the antagonistic interface GFs hyper-acetylate chromatin at unmethylated promoters and enhancers of genes involved in motility, but GCs hypoacetylate the corresponding regions. In conclusion, unmethylated genomic regions that encode feedback regulatory modules and differentially recruit RNAPII and acetylases/deacetylases underlie the crosstalk between GFs and a steroid hormone.
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Affiliation(s)
- Yehoshua Enuka
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Morris E Feldman
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Animesh Chowdhury
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Swati Srivastava
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Moshit Lindzen
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Aldema Sas-Chen
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Renaud Massart
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - David Cheishvili
- Department of Pharmacology and Therapeutics, Sackler Program for Epigenetics and Developmental Psychobiology and McGill Centre for Bioinformatics, McGill University, Montreal, Quebec, Canada.,Department of Epigenetics and Developmental Psychobiology, McGill University, Montreal, Quebec H3A 0E7, Canada
| | - Matthew J Suderman
- Department of Pharmacology and Therapeutics, Sackler Program for Epigenetics and Developmental Psychobiology and McGill Centre for Bioinformatics, McGill University, Montreal, Quebec, Canada
| | - Yoav Zaltsman
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Chiara A Mazza
- Department of Experimental, Diagnostic and Specialty Medicine (DIMES), Unit of Histology, Embryology and Applied Biology, University of Bologna, Bologna 40126, Italy
| | - Kirti Shukla
- Division of Molecular Genome Analysis, German Cancer Research Center, Heidelberg, Germany
| | - Cindy Körner
- Division of Molecular Genome Analysis, German Cancer Research Center, Heidelberg, Germany
| | - Noa Furth
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Mattia Lauriola
- Department of Experimental, Diagnostic and Specialty Medicine (DIMES), Unit of Histology, Embryology and Applied Biology, University of Bologna, Bologna 40126, Italy
| | - Moshe Oren
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Stefan Wiemann
- Division of Molecular Genome Analysis, German Cancer Research Center, Heidelberg, Germany
| | - Moshe Szyf
- Department of Pharmacology and Therapeutics, Sackler Program for Epigenetics and Developmental Psychobiology and McGill Centre for Bioinformatics, McGill University, Montreal, Quebec, Canada.,Department of Epigenetics and Developmental Psychobiology, McGill University, Montreal, Quebec H3A 0E7, Canada
| | - Yosef Yarden
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
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18
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Carter SD, Mifsud KR, Reul JMHM. Acute Stress Enhances Epigenetic Modifications But Does Not Affect the Constitutive Binding of pCREB to Immediate-Early Gene Promoters in the Rat Hippocampus. Front Mol Neurosci 2017; 10:416. [PMID: 29311809 PMCID: PMC5742222 DOI: 10.3389/fnmol.2017.00416] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 11/30/2017] [Indexed: 01/13/2023] Open
Abstract
The immediate early genes (IEGs) c-Fos and Egr-1 are rapidly and transiently induced in sparse neurons within the hippocampus after exposure to an acute stressor. The induction of these genes is a critical part of the molecular mechanisms underlying successful behavioral adaptation to stress. Our previous work has shown that transcriptional activation of c-Fos and Egr-1 in the hippocampus requires formation of a dual histone mark within their promoter regions, the phosphorylation of serine 10 and acetylation of lysine 9/14 of histone H3. In the present study, using chromatin immuno-precipitation (ChIP), we found that an increase in the formation of H3K9ac-S10p occurs within the c-Fos and Egr-1 promoters after FS stress in vivo and that these histone modifications were located to promoter regions containing cAMP Responsive Elements (CREs), but not in neighboring regions containing only Serum Responsive Elements (SREs). Surprisingly, however, subsequent ChIP analyses showed no changes in the binding of pCREB or CREB-binding protein (CBP) to the CREs after FS. In fact, pCREB binding to the c-Fos and Egr-1 promoters was already highly enriched under baseline conditions and did not increase further after stress. We suggest that constitutive pCREB binding may keep c-Fos and Egr-1 in a poised state for activation. Possibly, the formation of H3K9ac-S10p in the vicinity of CRE sites may participate in unblocking transcriptional elongation through recruitment of additional epigenetic factors.
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Affiliation(s)
- Sylvia D Carter
- Neuro-Epigenetics Research Group, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Karen R Mifsud
- Neuro-Epigenetics Research Group, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Johannes M H M Reul
- Neuro-Epigenetics Research Group, Bristol Medical School, University of Bristol, Bristol, United Kingdom
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19
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Currie SL, Doane JJ, Evans KS, Bhachech N, Madison BJ, Lau DKW, McIntosh LP, Skalicky JJ, Clark KA, Graves BJ. ETV4 and AP1 Transcription Factors Form Multivalent Interactions with three Sites on the MED25 Activator-Interacting Domain. J Mol Biol 2017; 429:2975-2995. [PMID: 28728983 DOI: 10.1016/j.jmb.2017.06.024] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/04/2017] [Accepted: 06/05/2017] [Indexed: 01/05/2023]
Abstract
The recruitment of transcriptional cofactors by sequence-specific transcription factors challenges the basis of high affinity and selective interactions. Extending previous studies that the N-terminal activation domain (AD) of ETV5 interacts with Mediator subunit 25 (MED25), we establish that similar, aromatic-rich motifs located both in the AD and in the DNA-binding domain (DBD) of the related ETS factor ETV4 interact with MED25. These ETV4 regions bind MED25 independently, display distinct kinetics, and combine to contribute to a high-affinity interaction of full-length ETV4 with MED25. High-affinity interactions with MED25 are specific for the ETV1/4/5 subfamily as other ETS factors display weaker binding. The AD binds to a single site on MED25 and the DBD interacts with three MED25 sites, allowing for simultaneous binding of both domains in full-length ETV4. MED25 also stimulates the in vitro DNA binding activity of ETV4 by relieving autoinhibition. ETV1/4/5 factors are often overexpressed in prostate cancer and genome-wide studies in a prostate cancer cell line indicate that ETV4 and MED25 occupy enhancers that are enriched for ETS-binding sequences and are both functionally important for the transcription of genes regulated by these enhancers. AP1-motifs, which bind JUN and FOS transcription factor families, were observed in MED25-occupied regions and JUN/FOS also contact MED25; FOS strongly binds to the same MED25 site as ETV4 AD and JUN interacts with the other two MED25 sites. In summary, we describe features of the multivalent ETV4- and AP1-MED25 interactions, thereby implicating these factors in the recruitment of MED25 to transcriptional control elements.
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Affiliation(s)
- Simon L Currie
- Department of Oncological Sciences, University of Utah School of Medicine, Salt Lake City, UT, 84112-5500, USA; Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, 84112-5500, USA
| | - Jedediah J Doane
- Department of Oncological Sciences, University of Utah School of Medicine, Salt Lake City, UT, 84112-5500, USA; Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, 84112-5500, USA
| | - Kathryn S Evans
- Department of Oncological Sciences, University of Utah School of Medicine, Salt Lake City, UT, 84112-5500, USA; Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, 84112-5500, USA
| | - Niraja Bhachech
- Department of Oncological Sciences, University of Utah School of Medicine, Salt Lake City, UT, 84112-5500, USA; Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, 84112-5500, USA
| | - Bethany J Madison
- Department of Oncological Sciences, University of Utah School of Medicine, Salt Lake City, UT, 84112-5500, USA; Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, 84112-5500, USA
| | - Desmond K W Lau
- Departments of Biochemistry and Molecular Biology, Department of Chemistry, and Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Lawrence P McIntosh
- Departments of Biochemistry and Molecular Biology, Department of Chemistry, and Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Jack J Skalicky
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, 84112-5650, USA
| | - Kathleen A Clark
- Department of Oncological Sciences, University of Utah School of Medicine, Salt Lake City, UT, 84112-5500, USA; Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, 84112-5500, USA
| | - Barbara J Graves
- Department of Oncological Sciences, University of Utah School of Medicine, Salt Lake City, UT, 84112-5500, USA; Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, 84112-5500, USA; Howard Hughes Medical Institute, Chevy Chase, MD, 20815-6789, USA.
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20
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Esnault C, Gualdrini F, Horswell S, Kelly G, Stewart A, East P, Matthews N, Treisman R. ERK-Induced Activation of TCF Family of SRF Cofactors Initiates a Chromatin Modification Cascade Associated with Transcription. Mol Cell 2017; 65:1081-1095.e5. [PMID: 28286024 PMCID: PMC5364370 DOI: 10.1016/j.molcel.2017.02.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 12/19/2016] [Accepted: 02/06/2017] [Indexed: 12/20/2022]
Abstract
We investigated the relationship among ERK signaling, histone modifications, and transcription factor activity, focusing on the ERK-regulated ternary complex factor family of SRF partner proteins. In MEFs, activation of ERK by TPA stimulation induced a common pattern of H3K9acS10ph, H4K16ac, H3K27ac, H3K9acK14ac, and H3K4me3 at hundreds of transcription start site (TSS) regions and remote regulatory sites. The magnitude of the increase in histone modification correlated well with changes in transcription. H3K9acS10ph preceded the other modifications. Most induced changes were TCF dependent, but TCF-independent TSSs exhibited the same hierarchy, indicating that it reflects gene activation per se. Studies with TCF Elk-1 mutants showed that TCF-dependent ERK-induced histone modifications required Elk-1 to be phosphorylated and competent to activate transcription. Analysis of direct TCF-SRF target genes and chromatin modifiers confirmed this and showed that H3S10ph required only Elk-1 phosphorylation. Induction of histone modifications following ERK stimulation is thus directed by transcription factor activation and transcription.
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Affiliation(s)
- Cyril Esnault
- Signalling and Transcription Group, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Francesco Gualdrini
- Signalling and Transcription Group, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Stuart Horswell
- Bioinformatics and Biostatistics STP, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Gavin Kelly
- Bioinformatics and Biostatistics STP, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Aengus Stewart
- Bioinformatics and Biostatistics STP, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Phil East
- Bioinformatics and Biostatistics STP, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Nik Matthews
- Advanced Sequencing STP, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Richard Treisman
- Signalling and Transcription Group, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
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21
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Gualdrini F, Esnault C, Horswell S, Stewart A, Matthews N, Treisman R. SRF Co-factors Control the Balance between Cell Proliferation and Contractility. Mol Cell 2016; 64:1048-1061. [PMID: 27867007 PMCID: PMC5179500 DOI: 10.1016/j.molcel.2016.10.016] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 09/26/2016] [Accepted: 10/11/2016] [Indexed: 12/20/2022]
Abstract
The ERK-regulated ternary complex factors (TCFs) act with the transcription factor serum response factor (SRF) to activate mitogen-induced transcription. However, the extent of their involvement in the immediate-early transcriptional response, and their wider functional significance, has remained unclear. We show that, in MEFs, TCF inactivation significantly inhibits over 60% of TPA-inducible gene transcription and impairs cell proliferation. Using integrated SRF ChIP-seq and Hi-C data, we identified over 700 TCF-dependent SRF direct target genes involved in signaling, transcription, and proliferation. These also include a significant number of cytoskeletal gene targets for the Rho-regulated myocardin-related transcription factor (MRTF) SRF cofactor family. The TCFs act as general antagonists of MRTF-dependent SRF target gene expression, competing directly with the MRTFs for access to SRF. As a result, TCF-deficient MEFs exhibit hypercontractile and pro-invasive behavior. Thus, competition between TCFs and MRTFs for SRF determines the balance between antagonistic proliferative and contractile programs of gene expression.
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Affiliation(s)
- Francesco Gualdrini
- Signalling and Transcription Group, Francis Crick Institute, 1 Midland Rd, London NW1 1AT, UK
| | - Cyril Esnault
- Signalling and Transcription Group, Francis Crick Institute, 1 Midland Rd, London NW1 1AT, UK
| | - Stuart Horswell
- Bioinformatics and Biostatistics STP, Francis Crick Institute, 1 Midland Rd, London NW1 1AT, UK
| | - Aengus Stewart
- Bioinformatics and Biostatistics STP, Francis Crick Institute, 1 Midland Rd, London NW1 1AT, UK
| | - Nik Matthews
- Advanced Sequencing STP, Francis Crick Institute, 1 Midland Rd, London NW1 1AT, UK
| | - Richard Treisman
- Signalling and Transcription Group, Francis Crick Institute, 1 Midland Rd, London NW1 1AT, UK.
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Regulation of metabolism by the Mediator complex. BIOPHYSICS REPORTS 2016; 2:69-77. [PMID: 28018965 PMCID: PMC5138257 DOI: 10.1007/s41048-016-0031-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 02/15/2016] [Indexed: 01/11/2023] Open
Abstract
The Mediator complex was originally discovered in yeast, but it is conserved in all eukaryotes. Its best-known function is to regulate RNA polymerase II-dependent gene transcription. Although the mechanisms by which the Mediator complex regulates transcription are often complicated by the context-dependent regulation, this transcription cofactor complex plays a pivotal role in numerous biological pathways. Biochemical, molecular, and physiological studies using cancer cell lines or model organisms have established the current paradigm of the Mediator functions. However, the physiological roles of the mammalian Mediator complex remain poorly defined, but have attracted a great interest in recent years. In this short review, we will summarize some of the reported functions of selective Mediator subunits in the regulation of metabolism. These intriguing findings suggest that the Mediator complex may be an important player in nutrient sensing and energy balance in mammals.
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23
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Mylona A, Theillet FX, Foster C, Cheng TM, Miralles F, Bates PA, Selenko P, Treisman R. Opposing effects of Elk-1 multisite phosphorylation shape its response to ERK activation. Science 2016; 354:233-237. [PMID: 27738173 PMCID: PMC5321235 DOI: 10.1126/science.aad1872] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 08/23/2016] [Indexed: 12/17/2022]
Abstract
Multisite phosphorylation regulates many transcription factors, including the serum response factor partner Elk-1. Phosphorylation of the transcriptional activation domain (TAD) of Elk-1 by the protein kinase ERK at multiple sites potentiates recruitment of the Mediator transcriptional coactivator complex and transcriptional activation, but the roles of individual phosphorylation events had remained unclear. Using time-resolved nuclear magnetic resonance spectroscopy, we found that ERK2 phosphorylation proceeds at markedly different rates at eight TAD sites in vitro, which we classified as fast, intermediate, and slow. Mutagenesis experiments showed that phosphorylation of fast and intermediate sites promoted Mediator interaction and transcriptional activation, whereas modification of slow sites counteracted both functions, thereby limiting Elk-1 output. Progressive Elk-1 phosphorylation thus ensures a self-limiting response to ERK activation, which occurs independently of antagonizing phosphatase activity.
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Affiliation(s)
- Anastasia Mylona
- Signalling and Transcription Laboratory, Francis Crick Institute, Lincoln's Inn Fields Laboratory, London WC2A 3LY, UK
| | - Francois-Xavier Theillet
- In-Cell NMR Laboratory, Department of NMR-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), Berlin, Germany
| | - Charles Foster
- Signalling and Transcription Laboratory, Francis Crick Institute, Lincoln's Inn Fields Laboratory, London WC2A 3LY, UK
| | - Tammy M Cheng
- Biomolecular Modelling Laboratory, Francis Crick Institute, Lincoln's Inn Fields Laboratory, London WC2A 3LY, UK
| | - Francesc Miralles
- Signalling and Transcription Laboratory, Francis Crick Institute, Lincoln's Inn Fields Laboratory, London WC2A 3LY, UK. Molecular & Clinical Sciences Research Institute, St. George's, University of London, London SW17 0RE, UK
| | - Paul A Bates
- Biomolecular Modelling Laboratory, Francis Crick Institute, Lincoln's Inn Fields Laboratory, London WC2A 3LY, UK
| | - Philipp Selenko
- In-Cell NMR Laboratory, Department of NMR-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), Berlin, Germany
| | - Richard Treisman
- Signalling and Transcription Laboratory, Francis Crick Institute, Lincoln's Inn Fields Laboratory, London WC2A 3LY, UK.
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Bahrami S, Drabløs F. Gene regulation in the immediate-early response process. Adv Biol Regul 2016; 62:37-49. [PMID: 27220739 DOI: 10.1016/j.jbior.2016.05.001] [Citation(s) in RCA: 239] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 05/03/2016] [Indexed: 05/13/2023]
Abstract
Immediate-early genes (IEGs) can be activated and transcribed within minutes after stimulation, without the need for de novo protein synthesis, and they are stimulated in response to both cell-extrinsic and cell-intrinsic signals. Extracellular signals are transduced from the cell surface, through receptors activating a chain of proteins in the cell, in particular extracellular-signal-regulated kinases (ERKs), mitogen-activated protein kinases (MAPKs) and members of the RhoA-actin pathway. These communicate through a signaling cascade by adding phosphate groups to neighboring proteins, and this will eventually activate and translocate TFs to the nucleus and thereby induce gene expression. The gene activation also involves proximal and distal enhancers that interact with promoters to simulate gene expression. The immediate-early genes have essential biological roles, in particular in stress response, like the immune system, and in differentiation. Therefore they also have important roles in various diseases, including cancer development. In this paper we summarize some recent advances on key aspects of the activation and regulation of immediate-early genes.
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Affiliation(s)
- Shahram Bahrami
- Department of Cancer Research and Molecular Medicine, NTNU - Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; St. Olavs Hospital, Trondheim University Hospital, NO-7006 Trondheim, Norway.
| | - Finn Drabløs
- Department of Cancer Research and Molecular Medicine, NTNU - Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
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Saxton J, Ferjentsik Z, Ducker C, Johnson AD, Shaw PE. Stepwise evolution of Elk-1 in early deuterostomes. FEBS J 2016; 283:1025-38. [PMID: 26613204 DOI: 10.1111/febs.13607] [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: 10/20/2015] [Revised: 11/16/2015] [Accepted: 11/23/2015] [Indexed: 11/29/2022]
Abstract
Metazoans have multiple ETS paralogues with overlapping or indiscriminate biological functions. Elk-1, one of three mammalian ternary complex factors (TCFs), is a well-conserved, ETS domain-containing transcriptional regulator of mitogen-responsive genes that operates in concert with serum response factor (SRF). Nonetheless, its genetic role remains unresolved because the elk-1 gene could be deleted from the mouse genome seemingly without adverse effect. Here we have explored the evolution of Elk-1 to gain insight into its conserved biological role. We identified antecedent Elk-1 proteins in extant early metazoans and used amino acid sequence alignments to chart the appearance of domains characteristic of human Elk-1. We then performed biochemical studies to determine whether putative domains apparent in the Elk-1 protein of a primitive hemichordate were functionally orthologous to those of human Elk-1. Our findings imply the existence of primordial Elk-1 proteins in primitive deuterostomes that could operate as mitogen-responsive ETS transcription factors but not as TCFs. The role of TCF was acquired later, but presumably prior to the whole genome duplications in the basal vertebrate lineage. Thus its evolutionary origins link Elk-1 to the appearance of mesoderm.
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Affiliation(s)
- Janice Saxton
- School of Life Sciences, University of Nottingham, UK
| | | | | | | | - Peter E Shaw
- School of Life Sciences, University of Nottingham, UK
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Wang C, Du X, Mou Z. The Mediator Complex Subunits MED14, MED15, and MED16 Are Involved in Defense Signaling Crosstalk in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2016; 7:1947. [PMID: 28066497 PMCID: PMC5177743 DOI: 10.3389/fpls.2016.01947] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 12/07/2016] [Indexed: 05/20/2023]
Abstract
Mediator is a highly conserved protein complex that functions as a transcriptional coactivator in RNA polymerase II (RNAPII)-mediated transcription. The Arabidopsis Mediator complex has recently been implicated in plant immune responses. Here, we compared salicylic acid (SA)-, methyl jasmonate (MeJA)-, and the ethylene (ET) precursor 1-aminocyclopropane-1-carboxylic acid (ACC)-induced defense and/or wound-responsive gene expression in 14 Arabidopsis Mediator subunit mutants. Our results show that MED14, MED15, and MED16 are required for SA-activated expression of the defense marker gene PATHOEGNESIS-RELATED GENE1, MED25 is required for MeJA-induced expression of the wound-responsive marker gene VEGATATIVE STORAGE PROTEIN1 (VSP1), MED8, MED14, MED15, MED16, MED18, MED20a, MED25, MED31, and MED33A/B (MED33a and MED33B) are required for MeJA-induced expression of the defense maker gene PLANT DEFENSIN1.2 (PDF1.2), and MED8, MED14, MED15, MED16, MED25, and MED33A/B are also required for ACC-triggered expression of PDF1.2. Furthermore, we investigated the involvement of MED14, MED15, and MED16 in plant defense signaling crosstalk and found that MED14, MED15, and MED16 are required for SA- and ET-mediated suppression of MeJA-induced VSP1 expression. This result suggests that MED14, MED15, and MED16 not only relay defense signaling from the SA and JA/ET defense pathways to the RNAPII transcription machinery, but also fine-tune defense signaling crosstalk. Finally, we show that MED33A/B contributes to the necrotrophic fungal pathogen Botrytis cinerea-induced expression of the defense genes PDF1.2, HEVEIN-LIKE, and BASIC CHITINASE and is required for full-scale basal resistance to B. cinerea, demonstrating a positive role for MED33 in plant immunity against necrotrophic fungal pathogens.
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Affiliation(s)
- Chenggang Wang
- Department of Microbiology and Cell Science, University of Florida, GainesvilleFL, USA
| | - Xuezhu Du
- College of Life Science, Hubei UniversityWuhan, China
| | - Zhonglin Mou
- Department of Microbiology and Cell Science, University of Florida, GainesvilleFL, USA
- *Correspondence: Zhonglin Mou,
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The Mediator Kinase Module Restrains Epidermal Growth Factor Receptor Signaling and Represses Vulval Cell Fate Specification in Caenorhabditis elegans. Genetics 2015; 202:583-99. [PMID: 26715664 DOI: 10.1534/genetics.115.180265] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 12/18/2015] [Indexed: 12/27/2022] Open
Abstract
Cell signaling pathways that control proliferation and determine cell fates are tightly regulated to prevent developmental anomalies and cancer. Transcription factors and coregulators are important effectors of signaling pathway output, as they regulate downstream gene programs. In Caenorhabditis elegans, several subunits of the Mediator transcriptional coregulator complex promote or inhibit vulva development, but pertinent mechanisms are poorly defined. Here, we show that Mediator's dissociable cyclin dependent kinase 8 (CDK8) module (CKM), consisting of cdk-8, cic-1/Cyclin C, mdt-12/dpy-22, and mdt-13/let-19, is required to inhibit ectopic vulval cell fates downstream of the epidermal growth factor receptor (EGFR)-Ras-extracellular signal-regulated kinase (ERK) pathway. cdk-8 inhibits ectopic vulva formation by acting downstream of mpk-1/ERK, cell autonomously in vulval cells, and in a kinase-dependent manner. We also provide evidence that the CKM acts as a corepressor for the Ets-family transcription factor LIN-1, as cdk-8 promotes transcriptional repression by LIN-1. In addition, we find that CKM mutation alters Mediator subunit requirements in vulva development: the mdt-23/sur-2 subunit, which is required for vulva development in wild-type worms, is dispensable for ectopic vulva formation in CKM mutants, which instead display hallmarks of unrestrained Mediator tail module activity. We propose a model whereby the CKM controls EGFR-Ras-ERK transcriptional output by corepressing LIN-1 and by fine tuning Mediator specificity, thus balancing transcriptional repression vs. activation in a critical developmental signaling pathway. Collectively, these data offer an explanation for CKM repression of EGFR signaling output and ectopic vulva formation and provide the first evidence of Mediator CKM-tail module subunit crosstalk in animals.
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28
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Wang C, Yao J, Du X, Zhang Y, Sun Y, Rollins JA, Mou Z. The Arabidopsis Mediator Complex Subunit16 Is a Key Component of Basal Resistance against the Necrotrophic Fungal Pathogen Sclerotinia sclerotiorum. PLANT PHYSIOLOGY 2015; 169:856-72. [PMID: 26143252 PMCID: PMC4577384 DOI: 10.1104/pp.15.00351] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 07/01/2015] [Indexed: 05/19/2023]
Abstract
Although Sclerotinia sclerotiorum is a devastating necrotrophic fungal plant pathogen in agriculture, the virulence mechanisms utilized by S. sclerotiorum and the host defense mechanisms against this pathogen have not been fully understood. Here, we report that the Arabidopsis (Arabidopsis thaliana) Mediator complex subunit MED16 is a key component of basal resistance against S. sclerotiorum. Mutants of MED16 are markedly more susceptible to S. sclerotiorum than mutants of 13 other Mediator subunits, and med16 has a much stronger effect on S. sclerotiorum-induced transcriptome changes compared with med8, a mutation not altering susceptibility to S. sclerotiorum. Interestingly, med16 is also more susceptible to S. sclerotiorum than coronatine-insensitive1-1 (coi1-1), which is the most susceptible mutant reported so far. Although the jasmonic acid (JA)/ethylene (ET) defense pathway marker gene PLANT DEFENSIN1.2 (PDF1.2) cannot be induced in either med16 or coi1-1, basal transcript levels of PDF1.2 in med16 are significantly lower than in coi1-1. Furthermore, ET-induced suppression of JA-activated wound responses is compromised in med16, suggesting a role for MED16 in JA-ET cross talk. Additionally, MED16 is required for the recruitment of RNA polymerase II to PDF1.2 and OCTADECANOID-RESPONSIVE ARABIDOPSIS ETHYLENE/ETHYLENE-RESPONSIVE FACTOR59 (ORA59), two target genes of both JA/ET-mediated and the transcription factor WRKY33-activated defense pathways. Finally, MED16 is physically associated with WRKY33 in yeast and in planta, and WRKY33-activated transcription of PDF1.2 and ORA59 as well as resistance to S. sclerotiorum depends on MED16. Taken together, these results indicate that MED16 regulates resistance to S. sclerotiorum by governing both JA/ET-mediated and WRKY33-activated defense signaling in Arabidopsis.
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Affiliation(s)
- Chenggang Wang
- Department of Microbiology and Cell Science (C.W., Z.M.) and Department of Plant Pathology (J.A.R.), University of Florida, Gainesville, Florida 32611;Department of Microbiology and Immunology, University of Buffalo, Buffalo, New York 14203 (J.Y., Y.S.);College of Life Science, Hubei University, Wuhan 430062, China (X.D.); andInterdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, Florida 32601 (Y.Z.)
| | - Jin Yao
- Department of Microbiology and Cell Science (C.W., Z.M.) and Department of Plant Pathology (J.A.R.), University of Florida, Gainesville, Florida 32611;Department of Microbiology and Immunology, University of Buffalo, Buffalo, New York 14203 (J.Y., Y.S.);College of Life Science, Hubei University, Wuhan 430062, China (X.D.); andInterdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, Florida 32601 (Y.Z.)
| | - Xuezhu Du
- Department of Microbiology and Cell Science (C.W., Z.M.) and Department of Plant Pathology (J.A.R.), University of Florida, Gainesville, Florida 32611;Department of Microbiology and Immunology, University of Buffalo, Buffalo, New York 14203 (J.Y., Y.S.);College of Life Science, Hubei University, Wuhan 430062, China (X.D.); andInterdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, Florida 32601 (Y.Z.)
| | - Yanping Zhang
- Department of Microbiology and Cell Science (C.W., Z.M.) and Department of Plant Pathology (J.A.R.), University of Florida, Gainesville, Florida 32611;Department of Microbiology and Immunology, University of Buffalo, Buffalo, New York 14203 (J.Y., Y.S.);College of Life Science, Hubei University, Wuhan 430062, China (X.D.); andInterdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, Florida 32601 (Y.Z.)
| | - Yijun Sun
- Department of Microbiology and Cell Science (C.W., Z.M.) and Department of Plant Pathology (J.A.R.), University of Florida, Gainesville, Florida 32611;Department of Microbiology and Immunology, University of Buffalo, Buffalo, New York 14203 (J.Y., Y.S.);College of Life Science, Hubei University, Wuhan 430062, China (X.D.); andInterdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, Florida 32601 (Y.Z.)
| | - Jeffrey A Rollins
- Department of Microbiology and Cell Science (C.W., Z.M.) and Department of Plant Pathology (J.A.R.), University of Florida, Gainesville, Florida 32611;Department of Microbiology and Immunology, University of Buffalo, Buffalo, New York 14203 (J.Y., Y.S.);College of Life Science, Hubei University, Wuhan 430062, China (X.D.); andInterdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, Florida 32601 (Y.Z.)
| | - Zhonglin Mou
- Department of Microbiology and Cell Science (C.W., Z.M.) and Department of Plant Pathology (J.A.R.), University of Florida, Gainesville, Florida 32611;Department of Microbiology and Immunology, University of Buffalo, Buffalo, New York 14203 (J.Y., Y.S.);College of Life Science, Hubei University, Wuhan 430062, China (X.D.); andInterdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, Florida 32601 (Y.Z.)
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Yao X, Tang Z, Fu X, Yin J, Liang Y, Li C, Li H, Tian Q, Roeder RG, Wang G. The Mediator subunit MED23 couples H2B mono-ubiquitination to transcriptional control and cell fate determination. EMBO J 2015; 34:2885-902. [PMID: 26330467 DOI: 10.15252/embj.201591279] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 08/10/2015] [Indexed: 01/18/2023] Open
Abstract
The Mediator complex orchestrates multiple transcription factors with the Pol II apparatus for precise transcriptional control. However, its interplay with the surrounding chromatin remains poorly understood. Here, we analyze differential histone modifications between WT and MED23(-/-) (KO) cells and identify H2B mono-ubiquitination at lysine 120 (H2Bub) as a MED23-dependent histone modification. Using tandem affinity purification and mass spectrometry, we find that MED23 associates with the RNF20/40 complex, the enzyme for H2Bub, and show that this association is critical for the recruitment of RNF20/40 to chromatin. In a cell-free system, Mediator directly and substantially increases H2Bub on recombinant chromatin through its cooperation with RNF20/40 and the PAF complex. Integrative genome-wide analyses show that MED23 depletion specifically reduces H2Bub on a subset of MED23-controlled genes. Importantly, MED23-coupled H2Bub levels are oppositely regulated during myogenesis and lung carcinogenesis. In sum, these results establish a mechanistic link between the Mediator complex and a critical chromatin modification in coordinating transcription with cell growth and differentiation.
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Affiliation(s)
- Xiao Yao
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China
| | - Zhanyun Tang
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Xing Fu
- Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China
| | - Jingwen Yin
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China
| | - Yan Liang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China
| | - Chonghui Li
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China
| | - Huayun Li
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China
| | - Qing Tian
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China
| | - Robert G Roeder
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Gang Wang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China
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Landrieu I, Verger A, Baert JL, Rucktooa P, Cantrelle FX, Dewitte F, Ferreira E, Lens Z, Villeret V, Monté D. Characterization of ERM transactivation domain binding to the ACID/PTOV domain of the Mediator subunit MED25. Nucleic Acids Res 2015; 43:7110-21. [PMID: 26130716 PMCID: PMC4538835 DOI: 10.1093/nar/gkv650] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 05/28/2015] [Indexed: 01/12/2023] Open
Abstract
The N-terminal acidic transactivation domain (TAD) of ERM/ETV5 (ERM38–68), a PEA3 group member of Ets-related transcription factors, directly interacts with the ACID/PTOV domain of the Mediator complex subunit MED25. Molecular details of this interaction were investigated using nuclear magnetic resonance (NMR) spectroscopy. The TAD is disordered in solution but has a propensity to adopt local transient secondary structure. We show that it folds upon binding to MED25 and that the resulting ERM–MED25 complex displays characteristics of a fuzzy complex. Mutational analysis further reveals that two aromatic residues in the ERM TAD (F47 and W57) are involved in the binding to MED25 and participate in the ability of ERM TAD to activate transcription. Mutation of a key residue Q451 in the VP16 H1 binding pocket of MED25 affects the binding of ERM. Furthermore, competition experiments show that ERM and VP16 H1 share a common binding interface on MED25. NMR data confirms the occupancy of this binding pocket by ERM TAD. Based on these experimental data, a structural model of a functional interaction is proposed. This study provides mechanistic insights into the Mediator–transactivator interactions.
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Affiliation(s)
- Isabelle Landrieu
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - Alexis Verger
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - Jean-Luc Baert
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - Prakash Rucktooa
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - François-Xavier Cantrelle
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - Frédérique Dewitte
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - Elisabeth Ferreira
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - Zoé Lens
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - Vincent Villeret
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
| | - Didier Monté
- CNRS UMR 8576, Université de Lille, Parc CNRS de la Haute Borne, 50 avenue de Halley, B.P. 70478, 59658 Villeneuve d'Ascq Cedex, France
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31
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Lee YJ, Han ME, Baek SJ, Kim SY, Oh SO. MED30 Regulates the Proliferation and Motility of Gastric Cancer Cells. PLoS One 2015; 10:e0130826. [PMID: 26110885 PMCID: PMC4482445 DOI: 10.1371/journal.pone.0130826] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 05/26/2015] [Indexed: 11/19/2022] Open
Abstract
MED30 is an essential member of the mediator complex that forms a hub between transcriptional activators and RNA polymerase II. However, the expressions and roles of MED30 have been poorly characterized in cancer. In this study, we examined the functional roles of MED30 during gastric cancer progression. It was found that MED30 was overexpressed in gastric cancer tissues and cell lines. Moreover, MED30 overexpression increased the proliferation, migration, and invasion of gastric cancer cells, whereas MED30 knockdown inhibited these effects. Furthermore the knockdown significantly inhibited tumorigenicity in SCID mice. MED30 also promoted the expressions of genes related to epithelial-mesenchymal transition and induced a fibroblast-like morphology. This study shows MED30 has pathophysiological roles in the proliferation, migration, and invasion of gastric cancer cells and suggests that MED30 should be viewed as a potent therapeutic target for malignant gastric carcinoma.
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Affiliation(s)
- Yong Joo Lee
- Department of Anatomy, School of Medicine, Pusan National University, Busan, Republic of Korea
| | - Myoung-Eun Han
- Department of Anatomy, School of Medicine, Pusan National University, Busan, Republic of Korea
- Medical Research Center for Ischemic Tissue Regeneration, Pusan National University, Busan, Republic of Korea
| | - Su-Jin Baek
- Medical Genomics Research Center, KRIBB, Daejeon, Republic of Korea
| | - Seon-Young Kim
- Medical Genomics Research Center, KRIBB, Daejeon, Republic of Korea
| | - Sae-Ock Oh
- Department of Anatomy, School of Medicine, Pusan National University, Busan, Republic of Korea
- * E-mail:
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Trehan A, Brady JM, Maduro V, Bone W, Huang Y, Golas GA, Kane M, Lee PR, Thurm A, Gropman AL, Paul SM, Vezina G, Markello TC, Gahl WA, Boerkoel CF, Tifft CJ. MED23-associated intellectual disability in a non-consanguineous family. Am J Med Genet A 2015; 167:1374-80. [PMID: 25845469 PMCID: PMC5671761 DOI: 10.1002/ajmg.a.37047] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 02/18/2015] [Indexed: 11/10/2022]
Abstract
Intellectual disability (ID) is a heterogeneous condition arising from a variety of environmental and genetic factors. Among these causes are defects in transcriptional regulators. Herein, we report on two brothers in a nonconsanguineous family with novel compound heterozygous, disease-segregating mutations (NM_015979.3: [3656A > G];[4006C > T], NP_057063.2: [H1219R];[R1336X]) in MED23. This gene encodes a subunit of the Mediator complex that modulates the expression of RNA polymerase II-dependent genes. These brothers, who had profound ID, spasticity, congenital heart disease, brain abnormalities, and atypical electroencephalography, represent the first case of MED23-associated ID in a non-consanguineous family. They also expand upon the clinical features previously reported for mutations in this gene.
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Affiliation(s)
- Aditi Trehan
- Office of the Clinical Director, NHGRI/NIH, Bethesda, Maryland, USA
- NIH Undiagnosed Diseases Program, NIH Office of Rare Diseases Research and NHGRI, Bethesda, Maryland, USA
| | - Jacqueline M. Brady
- Office of the Clinical Director, NHGRI/NIH, Bethesda, Maryland, USA
- NIH Undiagnosed Diseases Program, NIH Office of Rare Diseases Research and NHGRI, Bethesda, Maryland, USA
| | - Valerie Maduro
- Office of the Clinical Director, NHGRI/NIH, Bethesda, Maryland, USA
- NIH Undiagnosed Diseases Program, NIH Office of Rare Diseases Research and NHGRI, Bethesda, Maryland, USA
| | - William Bone
- Office of the Clinical Director, NHGRI/NIH, Bethesda, Maryland, USA
- NIH Undiagnosed Diseases Program, NIH Office of Rare Diseases Research and NHGRI, Bethesda, Maryland, USA
| | - Yan Huang
- Office of the Clinical Director, NHGRI/NIH, Bethesda, Maryland, USA
- NIH Undiagnosed Diseases Program, NIH Office of Rare Diseases Research and NHGRI, Bethesda, Maryland, USA
| | - Gretchen A. Golas
- Office of the Clinical Director, NHGRI/NIH, Bethesda, Maryland, USA
- NIH Undiagnosed Diseases Program, NIH Office of Rare Diseases Research and NHGRI, Bethesda, Maryland, USA
| | - Megan Kane
- NIH Undiagnosed Diseases Program, NIH Office of Rare Diseases Research and NHGRI, Bethesda, Maryland, USA
| | - Paul R. Lee
- National Institute of Neurological Disorder and Stroke, NIH, Bethesda, Maryland, USA
| | - Audrey Thurm
- Pediatrics and Developmental Neuroscience, NIMH/NIH, Bethesda, Maryland, USA
| | - Andrea L. Gropman
- Office of the Clinical Director, NHGRI/NIH, Bethesda, Maryland, USA
- George Washington University School of Medicine and Health Sciences and Children’s National Medical Center, Washington D.C., USA
| | - Scott M. Paul
- Rehabilitation Medicine Department, Clinical Center, NIH, Bethesda, Maryland, USA
| | - Gilbert Vezina
- George Washington University School of Medicine and Health Sciences and Children’s National Medical Center, Washington D.C., USA
| | - Thomas C. Markello
- NIH Undiagnosed Diseases Program, NIH Office of Rare Diseases Research and NHGRI, Bethesda, Maryland, USA
| | - William A. Gahl
- Office of the Clinical Director, NHGRI/NIH, Bethesda, Maryland, USA
- NIH Undiagnosed Diseases Program, NIH Office of Rare Diseases Research and NHGRI, Bethesda, Maryland, USA
| | - Cornelius F. Boerkoel
- NIH Undiagnosed Diseases Program, NIH Office of Rare Diseases Research and NHGRI, Bethesda, Maryland, USA
| | - Cynthia J. Tifft
- Office of the Clinical Director, NHGRI/NIH, Bethesda, Maryland, USA
- NIH Undiagnosed Diseases Program, NIH Office of Rare Diseases Research and NHGRI, Bethesda, Maryland, USA
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Biochemical and redox characterization of the mediator complex and its associated transcription factor GeBPL, a GLABROUS1 enhancer binding protein. Biochem J 2015; 468:385-400. [PMID: 25877331 DOI: 10.1042/bj20150132] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/16/2015] [Indexed: 12/23/2022]
Abstract
The eukaryotic mediator integrates regulatory signals from promoter-bound transcription factors (TFs) and transmits them to RNA polymerase II (Pol II) machinery. Although redox signalling is important in adjusting plant metabolism and development, nothing is known about a possible redox regulation of mediator. In the present study, using pull-down and yeast two-hybrid assays, we demonstrate the association of mediator (MED) subunits MED10a, MED28 and MED32 with the GLABROUS1 (GL1) enhancer-binding protein-like (GeBPL), a plant-specific TF that binds a promoter containing cryptochrome 1 response element 2 (CryR2) element. All the corresponding recombinant proteins form various types of covalent oligomers linked by intermolecular disulfide bonds that are reduced in vitro by the thioredoxin (TRX) and/or glutathione/glutaredoxin (GRX) systems. The presence of recombinant MED10a, MED28 and MED32 subunits or changes of its redox state affect the DNA-binding capacity of GeBPL suggesting that redox-driven conformational changes might modulate its activity. Overall, these results advance our understanding of how redox signalling affects transcription and identify mediator as a novel actor in redox signalling pathways, relaying or integrating redox changes in combination with specific TFs as GeBPL.
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Retroviral cyclin controls cyclin-dependent kinase 8-mediated transcription elongation and reinitiation. J Virol 2015; 89:5450-61. [PMID: 25741012 DOI: 10.1128/jvi.00464-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 02/24/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Walleye dermal sarcoma virus (WDSV) infection is associated with the seasonal development and regression of walleye dermal sarcoma. Previous work showed that the retroviral cyclin (RV-cyclin), encoded by WDSV, has separable cyclin box and transcription activation domains. It binds to cyclin-dependent kinase 8 (CDK8) and enhances its kinase activity. CDK8 is evolutionarily conserved and is frequently overexpressed in human cancers. It is normally activated by cyclin C and is required for transcription elongation of the serum response genes (immediate early genes [IEGs]) FOS, EGR1, and cJUN. The IEGs drive cell proliferation, and their expression is brief and highly regulated. Here we show that constitutive expression of RV-cyclin in the HCT116 colon cancer cell line significantly increases the level of IEG expression in response to serum stimulation. Quantitative reverse transcription-PCR (RT-PCR) and nuclear run-on assays provide evidence that RV-cyclin does not alter the initiation of IEG transcription but does enhance the overall rate of transcription elongation and maintains transcription reinitiation. RV-cyclin does not increase activating phosphorylation events in the mitogen-activated protein kinase pathway and does not inhibit decay of IEG mRNAs. At the EGR1 gene locus, RV-cyclin increases and maintains RNA polymerase II (Pol II) occupancy after serum stimulation, in conjunction with increased and extended EGR1 gene expression. The RV-cyclin increases CDK8 occupancy at the EGR1 gene locus before and after serum stimulation. Both of RV-cyclin's functional domains, i.e., the cyclin box and the activation domain, are necessary for the overall enhancement of IEG expression. RV-cyclin presents a novel and ancient mechanism of retrovirus-induced oncogenesis. IMPORTANCE The data reported here are important to both virology and cancer biology. The novel mechanism pinpoints CDK8 in the development of walleye dermal sarcoma and sheds light on CDK8's role in many human cancers. CDK8 controls expression from highly regulated genes, including the interferon-stimulated genes. Its function is likely the target of many viral interferon-resistance mechanisms. CDK8 also controls cellular responses to metabolic stimuli, stress, and hypoxia, in addition to the serum response. The retroviral cyclin (RV-cyclin) represents a highly selected probe of CDK8 function. RV-cyclin does not control CDK8 specificity but instead enhances CDK8's effects on regulated genes, an important distinction for its use to delineate natural CDK8 targets. The outcomes of this research are applicable to investigations of normal and abnormal CDK8 functions. The mechanisms defined here will contribute directly to the dermal sarcoma model in fish and clarify an important path for oncogenesis and innate resistance to viruses.
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Allen BL, Taatjes DJ. The Mediator complex: a central integrator of transcription. Nat Rev Mol Cell Biol 2015; 16:155-66. [PMID: 25693131 DOI: 10.1038/nrm3951] [Citation(s) in RCA: 594] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The RNA polymerase II (Pol II) enzyme transcribes all protein-coding and most non-coding RNA genes and is globally regulated by Mediator - a large, conformationally flexible protein complex with a variable subunit composition (for example, a four-subunit cyclin-dependent kinase 8 module can reversibly associate with it). These biochemical characteristics are fundamentally important for Mediator's ability to control various processes that are important for transcription, including the organization of chromatin architecture and the regulation of Pol II pre-initiation, initiation, re-initiation, pausing and elongation. Although Mediator exists in all eukaryotes, a variety of Mediator functions seem to be specific to metazoans, which is indicative of more diverse regulatory requirements.
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Affiliation(s)
- Benjamin L Allen
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80303, USA
| | - Dylan J Taatjes
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80303, USA
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Abstract
Skeletal and cardiac muscles play key roles in the regulation of systemic energy homeostasis and display remarkable plasticity in their metabolic responses to caloric availability and physical activity. In this Perspective we discuss recent studies highlighting transcriptional mechanisms that govern systemic metabolism by striated muscles. We focus on the participation of the Mediator complex in this process, and suggest that tissue-specific regulation of Mediator subunits impacts metabolic homeostasis.
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Affiliation(s)
- Kedryn K Baskin
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
| | - Benjamin R Winders
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA; Cardiology Division, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
| | - Eric N Olson
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA; Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA.
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Winberg J, Berggren H, Malm T, Johansson S, Johansson Ramgren J, Nilsson B, Liedén A, Nordenskjöld A, Gustavsson P, Nordgren A. No evidence for mosaic pathogenic copy number variations in cardiac tissue from patients with congenital heart malformations. Eur J Med Genet 2015; 58:129-33. [PMID: 25652018 DOI: 10.1016/j.ejmg.2015.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 01/10/2015] [Indexed: 11/28/2022]
Abstract
The aim of this study was to investigate if pathogenic copy number variations (CNVs) are present in mosaic form in patients with congenital heart malformations. We have collected cardiac tissue and blood samples from 23 patients with congenital heart malformations that underwent cardiac surgery and screened for mosaic gene dose alterations restricted to cardiac tissue using array comparative genomic hybridization (array CGH). We did not find evidence of CNVs in mosaic form after array CGH analysis. Pathogenic CNVs that were present in both cardiac tissue and blood were detected in 2/23 patients (9%), and in addition we found several constitutional CNVs of unclear clinical significance. This is the first study investigating mosaicism for CNVs in heart tissue compared to peripheral blood and the results do not indicate that pathogenic mosaic copy number changes are common in patients with heart malformations. Importantly, in line with previous studies, our results show that constitutional pathogenic CNVs are important factors contributing to congenital heart malformations.
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Affiliation(s)
- Johanna Winberg
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.
| | - Håkan Berggren
- Pediatric Cardiac Surgery Unit, Queen Silvia Children's Hospital, Gothenburg, Sweden
| | - Torsten Malm
- Pediatric Cardiac Surgery Unit, Children's Hospital, University Hospital, Lund, Sweden
| | - Sune Johansson
- Pediatric Cardiac Surgery Unit, Children's Hospital, University Hospital, Lund, Sweden
| | | | - Boris Nilsson
- Pediatric Cardiac Surgery Unit, Queen Silvia Children's Hospital, Gothenburg, Sweden
| | - Agne Liedén
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Agneta Nordenskjöld
- Department of Woman and Child Health and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden; Pediatric Surgery, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden
| | - Peter Gustavsson
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Ann Nordgren
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
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Zhu W, Yao X, Liang Y, Liang D, Song L, Jing N, Li J, Wang G. Mediator Med23 deficiency enhances neural differentiation of murine embryonic stem cells through modulating BMP signaling. Development 2015; 142:465-76. [PMID: 25564654 DOI: 10.1242/dev.112946] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Unraveling the mechanisms underlying early neural differentiation of embryonic stem cells (ESCs) is crucial to developing cell-based therapies of neurodegenerative diseases. Neural fate acquisition is proposed to be controlled by a 'default' mechanism, for which the molecular regulation is not well understood. In this study, we investigated the functional roles of Mediator Med23 in pluripotency and lineage commitment of murine ESCs. Unexpectedly, we found that, despite the largely unchanged pluripotency and self-renewal of ESCs, Med23 depletion rendered the cells prone to neural differentiation in different differentiation assays. Knockdown of two other Mediator subunits, Med1 and Med15, did not alter the neural differentiation of ESCs. Med15 knockdown selectively inhibited endoderm differentiation, suggesting the specificity of cell fate control by distinctive Mediator subunits. Gene profiling revealed that Med23 depletion attenuated BMP signaling in ESCs. Mechanistically, MED23 modulated Bmp4 expression by controlling the activity of ETS1, which is involved in Bmp4 promoter-enhancer communication. Interestingly, med23 knockdown in zebrafish embryos also enhanced neural development at early embryogenesis, which could be reversed by co-injection of bmp4 mRNA. Taken together, our study reveals an intrinsic, restrictive role of MED23 in early neural development, thus providing new molecular insights for neural fate determination.
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Affiliation(s)
- Wanqu Zhu
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiao Yao
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yan Liang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Dan Liang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Lu Song
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Naihe Jing
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jinsong Li
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Gang Wang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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A functional portrait of Med7 and the mediator complex in Candida albicans. PLoS Genet 2014; 10:e1004770. [PMID: 25375174 PMCID: PMC4222720 DOI: 10.1371/journal.pgen.1004770] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 09/22/2014] [Indexed: 11/19/2022] Open
Abstract
Mediator is a multi-subunit protein complex that regulates gene expression in eukaryotes by integrating physiological and developmental signals and transmitting them to the general RNA polymerase II machinery. We examined, in the fungal pathogen Candida albicans, a set of conditional alleles of genes encoding Mediator subunits of the head, middle, and tail modules that were found to be essential in the related ascomycete Saccharomyces cerevisiae. Intriguingly, while the Med4, 8, 10, 11, 14, 17, 21 and 22 subunits were essential in both fungi, the structurally highly conserved Med7 subunit was apparently non-essential in C. albicans. While loss of CaMed7 did not lead to loss of viability under normal growth conditions, it dramatically influenced the pathogen's ability to grow in different carbon sources, to form hyphae and biofilms, and to colonize the gastrointestinal tracts of mice. We used epitope tagging and location profiling of the Med7 subunit to examine the distribution of the DNA sites bound by Mediator during growth in either the yeast or the hyphal form, two distinct morphologies characterized by different transcription profiles. We observed a core set of 200 genes bound by Med7 under both conditions; this core set is expanded moderately during yeast growth, but is expanded considerably during hyphal growth, supporting the idea that Mediator binding correlates with changes in transcriptional activity and that this binding is condition specific. Med7 bound not only in the promoter regions of active genes but also within coding regions and at the 3′ ends of genes. By combining genome-wide location profiling, expression analyses and phenotyping, we have identified different Med7p-influenced regulons including genes related to glycolysis and the Filamentous Growth Regulator family. In the absence of Med7, the ribosomal regulon is de-repressed, suggesting Med7 is involved in central aspects of growth control. In this study, we have investigated Mediator function in the human fungal pathogen C. albicans. An initial screening of conditionally regulated Mediator subunits showed that the Med7 of C. albicans was not essential, in contrast to the situation noted for S. cerevisiae. While loss of CaMed7 did not lead to loss of viability under normal growth conditions, it dramatically influenced the pathogen's ability to grow in different carbon sources, to form hyphae and biofilms, and to colonize the gastrointestinal tracts of mice. We used location profiling to determine Mediator binding under yeast and hyphal morphologies characterized by different transcription profiles. We observed a core set of specific and common genes bound by Med7 under both conditions; this specific core set is expanded considerably during hyphal growth, supporting the idea that Mediator binding correlates with changes in transcriptional activity and that this binding is condition specific. Med7 bound not only in the promoter regions of active genes but also of inactive genes and within coding regions and at the 3′ ends of genes. By combining genome-wide location profiling, expression analyses and phenotyping, we have identified different Med7 regulons including genes related to glycolysis and the Filamentous Growth Regulator family.
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Kasper LH, Fukuyama T, Brindle PK. T-cells null for the MED23 subunit of mediator express decreased levels of KLF2 and inefficiently populate the peripheral lymphoid organs. PLoS One 2014; 9:e102076. [PMID: 25054639 PMCID: PMC4108324 DOI: 10.1371/journal.pone.0102076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 06/13/2014] [Indexed: 01/23/2023] Open
Abstract
MED23, a subunit of the Mediator coactivator complex, is important for the expression of a subset of MAPK/ERK pathway-responsive genes, the constituents of which vary between cell types for reasons that are not completely clear. MAPK/ERK pathway-dependent processes are essential for T-cell development and function, but whether MED23 has a role in this context is unknown. We generated Med23 conditional knockout mice and induced Med23 deletion in early T-cell development using the lineage specific Lck-Cre transgene. While the total cell number and distribution of cell populations in the thymuses of Med23flox/flox;Lck-Cre mice were essentially normal, MED23 null T-cells failed to efficiently populate the peripheral lymphoid organs. MED23 null thymocytes displayed decreased expression of the MAPK/ERK-responsive genes Egr1, Egr2, as well as of the membrane glycoprotein Cd52 (CAMPATH-1). MED23 null CD4 single-positive thymocytes also showed decreased expression of KLF2 (LKLF), a T-cell master regulatory transcription factor. Indeed, similarities between the phenotypes of mice lacking MED23 or KLF2 in T-cells suggest that KLF2 deficiency in MED23 null T-cells is one of their key defects. Mechanistic experiments using MED23 null MEFs further suggest that MED23 is required for full activity of the MAPK-responsive transcription factor MEF2, which has previously been shown to mediate Klf2 expression. In summary, our data indicate that MED23 has critical roles in enabling T-cells to populate the peripheral lymphoid organs, possibly by potentiating MEF2-dependent expression of the T-cell transcription factor KLF2.
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Affiliation(s)
- Lawryn H. Kasper
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
- * E-mail: (LHK); (PKB)
| | - Tomofusa Fukuyama
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Paul K. Brindle
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
- * E-mail: (LHK); (PKB)
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Esnault C, Stewart A, Gualdrini F, East P, Horswell S, Matthews N, Treisman R. Rho-actin signaling to the MRTF coactivators dominates the immediate transcriptional response to serum in fibroblasts. Genes Dev 2014; 28:943-58. [PMID: 24732378 PMCID: PMC4018493 DOI: 10.1101/gad.239327.114] [Citation(s) in RCA: 252] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 03/20/2014] [Indexed: 01/14/2023]
Abstract
The transcription factor SRF (serum response factor) recruits two families of coactivators, the MRTFs (myocardin-related transcription factors) and the TCFs (ternary complex factors), to couple gene transcription to growth factor signaling. Here we investigated the role of the SRF network in the immediate transcriptional response of fibroblasts to serum stimulation. SRF recruited its cofactors in a gene-specific manner, and virtually all MRTF binding was directed by SRF. Much of SRF DNA binding was serum-inducible, reflecting a requirement for MRTF-SRF complex formation in nucleosome displacement. We identified 960 serum-responsive SRF target genes, which were mostly MRTF-controlled, as assessed by MRTF chromatin immunoprecipitation (ChIP) combined with deep sequencing (ChIP-seq) and/or sensitivity to MRTF-linked signals. MRTF activation facilitates RNA polymerase II (Pol II) recruitment or promoter escape according to gene context. MRTF targets encode regulators of the cytoskeleton, transcription, and cell growth, underpinning the role of SRF in cytoskeletal dynamics and mechanosensing. Finally, we show that specific activation of either MRTFs or TCFs can reset the circadian clock.
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Affiliation(s)
| | | | | | - Phil East
- Bioinformatics and Biostatistics Group
| | | | - Nik Matthews
- Advanced Sequencing Facility, Cancer Research UK London Research Institute, London WC2A 3LY, United Kingdom
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Yin JW, Wang G. The Mediator complex: a master coordinator of transcription and cell lineage development. Development 2014; 141:977-87. [PMID: 24550107 DOI: 10.1242/dev.098392] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mediator is a multiprotein complex that is required for gene transcription by RNA polymerase II. Multiple subunits of the complex show specificity in relaying information from signals and transcription factors to the RNA polymerase II machinery, thus enabling control of the expression of specific genes. Recent studies have also provided novel mechanistic insights into the roles of Mediator in epigenetic regulation, transcriptional elongation, termination, mRNA processing, noncoding RNA activation and super enhancer formation. Based on these specific roles in gene regulation, Mediator has emerged as a master coordinator of development and cell lineage determination. Here, we describe the most recent advances in understanding the mechanisms of Mediator function, with an emphasis on its role during development and disease.
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Affiliation(s)
- Jing-wen Yin
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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Schiano C, Casamassimi A, Rienzo M, de Nigris F, Sommese L, Napoli C. Involvement of Mediator complex in malignancy. Biochim Biophys Acta Rev Cancer 2013; 1845:66-83. [PMID: 24342527 DOI: 10.1016/j.bbcan.2013.12.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 11/28/2013] [Accepted: 12/09/2013] [Indexed: 12/22/2022]
Abstract
Mediator complex (MED) is an evolutionarily conserved multiprotein, fundamental for growth and survival of all cells. In eukaryotes, the mRNA transcription is dependent on RNA polymerase II that is associated to various molecules like general transcription factors, MED subunits and chromatin regulators. To date, transcriptional machinery dysfunction has been shown to elicit broad effects on cell proliferation, development, differentiation, and pathologic disease induction, including cancer. Indeed, in malignant cells, the improper activation of specific genes is usually ascribed to aberrant transcription machinery. Here, we focus our attention on the correlation of MED subunits with carcinogenesis. To date, many subunits are mutated or display altered expression in human cancers. Particularly, the role of MED1, MED28, MED12, CDK8 and Cyclin C in cancer is well documented, although several studies have recently reported a possible association of other subunits with malignancy. Definitely, a major comprehension of the involvement of the whole complex in cancer may lead to the identification of MED subunits as novel diagnostic/prognostic tumour markers to be used in combination with imaging technique in clinical oncology, and to develop novel anti-cancer targets for molecular-targeted therapy.
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Affiliation(s)
- Concetta Schiano
- Institute of Diagnostic and Nuclear Development (SDN), IRCCS, Via E. Gianturco 113, 80143 Naples, Italy
| | - Amelia Casamassimi
- Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Via L. De Crecchio 7, 80138 Naples, Italy.
| | - Monica Rienzo
- Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Via L. De Crecchio 7, 80138 Naples, Italy
| | - Filomena de Nigris
- Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Via L. De Crecchio 7, 80138 Naples, Italy
| | - Linda Sommese
- U.O.C. Immunohematology, Transfusion Medicine and Transplant Immunology [SIMT], Regional Reference Laboratory of Transplant Immunology [LIT], Azienda Universitaria Policlinico (AOU), 1st School of Medicine, Second University of Naples, Piazza Miraglia 2, 80138 Naples, Italy
| | - Claudio Napoli
- Institute of Diagnostic and Nuclear Development (SDN), IRCCS, Via E. Gianturco 113, 80143 Naples, Italy; Department of Biochemistry, Biophysics and General Pathology, Second University of Naples, Via L. De Crecchio 7, 80138 Naples, Italy; U.O.C. Immunohematology, Transfusion Medicine and Transplant Immunology [SIMT], Regional Reference Laboratory of Transplant Immunology [LIT], Azienda Universitaria Policlinico (AOU), 1st School of Medicine, Second University of Naples, Piazza Miraglia 2, 80138 Naples, Italy
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Abstract
The Mediator complex is a multi-subunit assembly that appears to be required for regulating expression of most RNA polymerase II (pol II) transcripts, which include protein-coding and most non-coding RNA genes. Mediator and pol II function within the pre-initiation complex (PIC), which consists of Mediator, pol II, TFIIA, TFIIB, TFIID, TFIIE, TFIIF and TFIIH and is approximately 4.0 MDa in size. Mediator serves as a central scaffold within the PIC and helps regulate pol II activity in ways that remain poorly understood. Mediator is also generally targeted by sequence-specific, DNA-binding transcription factors (TFs) that work to control gene expression programs in response to developmental or environmental cues. At a basic level, Mediator functions by relaying signals from TFs directly to the pol II enzyme, thereby facilitating TF-dependent regulation of gene expression. Thus, Mediator is essential for converting biological inputs (communicated by TFs) to physiological responses (via changes in gene expression). In this review, we summarize an expansive body of research on the Mediator complex, with an emphasis on yeast and mammalian complexes. We focus on the basics that underlie Mediator function, such as its structure and subunit composition, and describe its broad regulatory influence on gene expression, ranging from chromatin architecture to transcription initiation and elongation, to mRNA processing. We also describe factors that influence Mediator structure and activity, including TFs, non-coding RNAs and the CDK8 module.
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Affiliation(s)
- Zachary C Poss
- Department of Chemistry and Biochemistry, University of Colorado , Boulder, CO , USA
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Lee SK, Chen X, Huang L, Stargell LA. The head module of Mediator directs activation of preloaded RNAPII in vivo. Nucleic Acids Res 2013; 41:10124-34. [PMID: 24005039 PMCID: PMC3905900 DOI: 10.1093/nar/gkt796] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The successful synthesis of a transcript by RNA polymerase II (RNAPII) is a multistage process with distinct rate-limiting steps that can vary depending on the particular gene. A growing number of genes in a variety of organisms are regulated at steps after the recruitment of RNAPII. The best-characterized Saccharomyces cerevisiae gene regulated in this manner is CYC1. This gene has high occupancy of RNAPII under non-inducing conditions, defining it as a poised gene. Here, we find that subunits of the head module of Mediator, Med18 and Med20, and Med19 are required for activation of transcription at the CYC1 promoter in response to environmental cues. These subunits of Mediator are required at the preloaded promoter for normal levels of recruitment and activity of the general transcription factor TFIIH. Strikingly, these Mediator components are dispensable for activation by the same activator at a different gene, which lacks a preloaded polymerase in the promoter region. Based on these results and other studies, we speculate that Mediator plays an essential role in triggering an inactive polymerase at CYC1 into a productively elongating form.
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Affiliation(s)
- Sarah K Lee
- Department of Biochemistry and Molecular Biology, Colorado State University, CO 80523, USA
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Zhang X, Yao J, Zhang Y, Sun Y, Mou Z. The Arabidopsis Mediator complex subunits MED14/SWP and MED16/SFR6/IEN1 differentially regulate defense gene expression in plant immune responses. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 75:484-97. [PMID: 23607369 DOI: 10.1111/tpj.12216] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 04/17/2013] [Accepted: 04/19/2013] [Indexed: 05/20/2023]
Abstract
Pathogen infection in plants triggers large-scale transcriptional changes, both locally and systemically. Emerging evidence suggests that the Arabidopsis Mediator complex plays a crucial role in these transcriptional changes. Mediator is highly conserved in eukaryotes, and its core comprises more than 20 subunits organized into three modules named head, middle and tail. The head and middle modules interact with general transcription factors and RNA polymerase II, whereas the tail module associates with activators, and signals through the head and middle modules to the basal transcription machinery. In Arabidopsis, three tail module subunits, MED14, MED15 and MED16, have been identified. Both MED15 and MED16 have been implicated in plant immunity, but the role of MED14 has not been established. Here, we report the characterization of an Arabidopsis T-DNA insertion mutant of the MED14 gene. Similarly to the med15 and/or med16 mutations, the med14 mutation significantly suppresses salicylic acid-induced defense responses, alters transcriptional changes induced by the avirulent bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000/avrRpt2, and renders plants susceptible to both Pst DC3000/avrRpt2 and Pst DC3000. The med14 mutation also completely compromises biological induction of systemic acquired resistance (SAR), indicating that the tail module as a whole is essential for SAR. Interestingly, unlike the med16 mutation, which differentially affects expression of several SAR positive and negative regulators, med14 inhibits induction of a large group of defense genes, including both SAR positive and negative regulators, suggesting that individual subunits of the Mediator tail module employ distinct mechanisms to regulate plant immune responses.
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Affiliation(s)
- Xudong Zhang
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL 32611, USA
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Abstract
The human Mediator complex is a central integrator for transcription and represents a primary interface that allows DNA-binding transcription factors to communicate their regulatory signals to the RNA polymerase II enzyme. Because Mediator is dynamic both in terms of subunit composition and structure, it presents challenges as a target for small molecule probes. Moreover, little high-resolution structural information exists for Mediator. Its global requirement for transcription, as well as its distinct, transcription factor specific interaction surfaces, however, suggest that development of probes that bind specific Mediator subunits might enable gene- and pathway-specific modulation of transcription. Here we provide a brief overview of the Mediator complex, highlighting biological and structural features that make it an attractive target for molecular probes. We then outline several chemical strategies that might be effective for targeting the complex.
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Affiliation(s)
| | - Dylan J Taatjes
- Dept. of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80303 USA
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Barford D, Takagi Y, Schultz P, Berger I. Baculovirus expression: tackling the complexity challenge. Curr Opin Struct Biol 2013; 23:357-64. [PMID: 23628287 PMCID: PMC7125881 DOI: 10.1016/j.sbi.2013.03.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 03/18/2013] [Accepted: 03/29/2013] [Indexed: 10/26/2022]
Abstract
Most essential functions in eukaryotic cells are catalyzed by complex molecular machines built of many subunits. To fully understand their biological function in health and disease, it is imperative to study these machines in their entirety. The provision of many essential multiprotein complexes of higher eukaryotes including humans, can be a considerable challenge, as low abundance and heterogeneity often rule out their extraction from native source material. The baculovirus expression vector system (BEVS), specifically tailored for multiprotein complex production, has proven itself to be uniquely suited for overcoming this impeding bottleneck. Here we highlight recent major achievements in multiprotein complex structure research that were catalyzed by this versatile recombinant complex expression tool.
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Affiliation(s)
- David Barford
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, UK
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Bancerek J, Poss ZC, Steinparzer I, Sedlyarov V, Pfaffenwimmer T, Mikulic I, Dölken L, Strobl B, Müller M, Taatjes DJ, Kovarik P. CDK8 kinase phosphorylates transcription factor STAT1 to selectively regulate the interferon response. Immunity 2013; 38:250-62. [PMID: 23352233 PMCID: PMC3580287 DOI: 10.1016/j.immuni.2012.10.017] [Citation(s) in RCA: 197] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2012] [Accepted: 10/24/2012] [Indexed: 11/25/2022]
Abstract
Gene regulation by cytokine-activated transcription factors of the signal transducer and activator of transcription (STAT) family requires serine phosphorylation within the transactivation domain (TAD). STAT1 and STAT3 TAD phosphorylation occurs upon promoter binding by an unknown kinase. Here, we show that the cyclin-dependent kinase 8 (CDK8) module of the Mediator complex phosphorylated regulatory sites within the TADs of STAT1, STAT3, and STAT5, including S727 within the STAT1 TAD in the interferon (IFN) signaling pathway. We also observed a CDK8 requirement for IFN-γ-inducible antiviral responses. Microarray analyses revealed that CDK8-mediated STAT1 phosphorylation positively or negatively regulated over 40% of IFN-γ-responsive genes, and RNA polymerase II occupancy correlated with gene expression changes. This divergent regulation occurred despite similar CDK8 occupancy at both S727 phosphorylation-dependent and -independent genes. These data identify CDK8 as a key regulator of STAT1 and antiviral responses and suggest a general role for CDK8 in STAT-mediated transcription. As such, CDK8 represents a promising target for therapeutic manipulation of cytokine responses.
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Affiliation(s)
- Joanna Bancerek
- Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, A-1030 Vienna, Austria
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Affiliation(s)
- Arnold J Berk
- Department of Microbiology, Immunology and Molecular Genetics, Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA.
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