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Maji S, Waseem M, Sharma MK, Singh M, Singh A, Dwivedi N, Thakur P, Cooper DG, Bisht NC, Fassler JS, Subbarao N, Khurana JP, Bhavesh NS, Thakur JK. MediatorWeb: a protein-protein interaction network database for the RNA polymerase II Mediator complex. FEBS J 2024. [PMID: 38975839 DOI: 10.1111/febs.17225] [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: 06/08/2023] [Revised: 04/24/2024] [Accepted: 06/28/2024] [Indexed: 07/09/2024]
Abstract
The protein-protein interaction (PPI) network of the Mediator complex is very tightly regulated and depends on different developmental and environmental cues. Here, we present an interactive platform for comparative analysis of the Mediator subunits from humans, baker's yeast Saccharomyces cerevisiae, and model plant Arabidopsis thaliana in a user-friendly web-interface database called MediatorWeb. MediatorWeb provides an interface to visualize and analyze the PPI network of Mediator subunits. The database facilitates downloading the untargeted and unweighted network of Mediator complex, its submodules, and individual Mediator subunits to better visualize the importance of individual Mediator subunits or their submodules. Further, MediatorWeb offers network visualization of the Mediator complex and interacting proteins that are functionally annotated. This feature provides clues to understand functions of Mediator subunits in different processes. In an additional tab, MediatorWeb provides quick access to secondary and tertiary structures, as well as residue-level contact information for Mediator subunits in each of the three model organisms. Another useful feature of MediatorWeb is detection of interologs based on orthologous analyses, which can provide clues to understand the functions of Mediator complex in less explored kingdoms. Thus, MediatorWeb and its features can help the user to understand the role of Mediator complex and its subunits in the transcription regulation of gene expression.
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Grants
- BT/PR40146/BTIS/137/4/2020 Department of Biotechnology, Ministry of Science and Technology, India
- BT/PR40169/BTIS/137/71/2023 Department of Biotechnology, Ministry of Science and Technology, India
- BT/HRD/MK-YRFP/50/27/2021 Department of Biotechnology, Ministry of Science and Technology, India
- BT/HRD/MK-YRFP/50/26/2021 Department of Biotechnology, Ministry of Science and Technology, India
- SERB, Government of India
- ICMR
- Council of Scientific and Industrial Research, India
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Affiliation(s)
- Sourobh Maji
- Plant Transcription Regulation, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
- Transcription Regulation, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Mohd Waseem
- National Institute of Plant Genome Research, New Delhi, India
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | | | - Maninder Singh
- National Institute of Plant Genome Research, New Delhi, India
| | - Anamika Singh
- Plant Transcription Regulation, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Nidhi Dwivedi
- National Institute of Plant Genome Research, New Delhi, India
| | - Pallabi Thakur
- National Institute of Plant Genome Research, New Delhi, India
| | - David G Cooper
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, IN, USA
| | - Naveen C Bisht
- National Institute of Plant Genome Research, New Delhi, India
| | | | - Naidu Subbarao
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Jitendra P Khurana
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | - Neel Sarovar Bhavesh
- Transcription Regulation, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Jitendra Kumar Thakur
- Plant Transcription Regulation, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- National Institute of Plant Genome Research, New Delhi, India
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2
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Yang JH, Hansen AS. Enhancer selectivity in space and time: from enhancer-promoter interactions to promoter activation. Nat Rev Mol Cell Biol 2024; 25:574-591. [PMID: 38413840 DOI: 10.1038/s41580-024-00710-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2024] [Indexed: 02/29/2024]
Abstract
The primary regulators of metazoan gene expression are enhancers, originally functionally defined as DNA sequences that can activate transcription at promoters in an orientation-independent and distance-independent manner. Despite being crucial for gene regulation in animals, what mechanisms underlie enhancer selectivity for promoters, and more fundamentally, how enhancers interact with promoters and activate transcription, remain poorly understood. In this Review, we first discuss current models of enhancer-promoter interactions in space and time and how enhancers affect transcription activation. Next, we discuss different mechanisms that mediate enhancer selectivity, including repression, biochemical compatibility and regulation of 3D genome structure. Through 3D polymer simulations, we illustrate how the ability of 3D genome folding mechanisms to mediate enhancer selectivity strongly varies for different enhancer-promoter interaction mechanisms. Finally, we discuss how recent technical advances may provide new insights into mechanisms of enhancer-promoter interactions and how technical biases in methods such as Hi-C and Micro-C and imaging techniques may affect their interpretation.
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Affiliation(s)
- Jin H Yang
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Gene Regulation Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research, Cambridge, MA, USA
| | - Anders S Hansen
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Gene Regulation Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Koch Institute for Integrative Cancer Research, Cambridge, MA, USA.
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3
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Freytes SN, Gobbini ML, Cerdán PD. The Plant Mediator Complex in the Initiation of Transcription by RNA Polymerase II. ANNUAL REVIEW OF PLANT BIOLOGY 2024; 75:211-237. [PMID: 38277699 DOI: 10.1146/annurev-arplant-070623-114005] [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: 01/28/2024]
Abstract
Thirty years have passed since the discovery of the Mediator complex in yeast. We are witnessing breakthroughs and advances that have led to high-resolution structural models of yeast and mammalian Mediators in the preinitiation complex, showing how it is assembled and how it positions the RNA polymerase II and its C-terminal domain (CTD) to facilitate the CTD phosphorylation that initiates transcription. This information may be also used to guide future plant research on the mechanisms of Mediator transcriptional control. Here, we review what we know about the subunit composition and structure of plant Mediators, the roles of the individual subunits and the genetic analyses that pioneered Mediator research, and how transcription factors recruit Mediators to regulatory regions adjoining promoters. What emerges from the research is a Mediator that regulates transcription activity and recruits hormonal signaling modules and histone-modifying activities to set up an off or on transcriptional state that recruits general transcription factors for preinitiation complex assembly.
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Affiliation(s)
| | | | - Pablo D Cerdán
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina; , ,
- Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina
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4
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Abdel-Fattah WR, Carlsson M, Hu GZ, Singh A, Vergara A, Aslam R, Ronne H, Björklund S. Growth-regulated co-occupancy of Mediator and Lsm3 at intronic ribosomal protein genes. Nucleic Acids Res 2024; 52:6220-6233. [PMID: 38613396 PMCID: PMC11194063 DOI: 10.1093/nar/gkae266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 03/22/2024] [Accepted: 04/01/2024] [Indexed: 04/14/2024] Open
Abstract
Mediator is a well-known transcriptional co-regulator and serves as an adaptor between gene-specific regulatory proteins and RNA polymerase II. Studies on the chromatin-bound form of Mediator revealed interactions with additional protein complexes involved in various transcription-related processes, such as the Lsm2-8 complex that is part of the spliceosomal U6 small nuclear ribonucleoprotein complex. Here, we employ Chromatin Immunoprecipitation sequencing (ChIP-seq) of chromatin associated with the Lsm3 protein and the Med1 or Med15 Mediator subunits. We identify 86 genes co-occupied by both Lsm3 and Mediator, of which 73 were intron-containing ribosomal protein genes. In logarithmically growing cells, Mediator primarily binds to their promoter regions but also shows a second, less pronounced occupancy at their 3'-exons. During the late exponential phase, we observe a near-complete transition of Mediator from these promoters to a position in their 3'-ends, overlapping the Lsm3 binding sites ∼250 bp downstream of their last intron-exon boundaries. Using an unbiased RNA sequencing approach, we show that transition of Mediator from promoters to the last exon of these genes correlates to reduction of both their messenger RNA levels and splicing ratios, indicating that the Mediator and Lsm complexes cooperate to control growth-regulated expression of intron-containing ribosomal protein genes at the levels of transcription and splicing.
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Affiliation(s)
- Wael R Abdel-Fattah
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Mattias Carlsson
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Box 7026, SE-750 07 Uppsala, Sweden
| | - Guo-Zhen Hu
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Box 7026, SE-750 07 Uppsala, Sweden
| | - Ajeet Singh
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Alexander Vergara
- Department of Plant Physiology, Umeå University, SE-901 87 Umeå, Sweden
| | - Rameen Aslam
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Hans Ronne
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Box 7026, SE-750 07 Uppsala, Sweden
| | - Stefan Björklund
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
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5
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Kolonay DW, Sattler KM, Strawser C, Rafael-Fortney J, Mihaylova MM, Miller KE, Lepper C, Baskin KK. Temporal regulation of the Mediator complex during muscle proliferation, differentiation, regeneration, aging, and disease. Front Cell Dev Biol 2024; 12:1331563. [PMID: 38690566 PMCID: PMC11058648 DOI: 10.3389/fcell.2024.1331563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 03/26/2024] [Indexed: 05/02/2024] Open
Abstract
Genesis of skeletal muscle relies on the differentiation and fusion of mono-nucleated muscle progenitor cells into the multi-nucleated muscle fiber syncytium. The temporally-controlled cellular and morphogenetic changes underlying this process are initiated by a series of highly coordinated transcription programs. At the core, the myogenic differentiation cascade is driven by muscle-specific transcription factors, i.e., the Myogenic Regulatory Factors (MRFs). Despite extensive knowledge on the function of individual MRFs, very little is known about how they are coordinated. Ultimately, highly specific coordination of these transcription programs is critical for their masterfully timed transitions, which in turn facilitates the intricate generation of skeletal muscle fibers from a naïve pool of progenitor cells. The Mediator complex links basal transcriptional machinery and transcription factors to regulate transcription and could be the integral component that coordinates transcription factor function during muscle differentiation, growth, and maturation. In this study, we systematically deciphered the changes in Mediator complex subunit expression in skeletal muscle development, regeneration, aging, and disease. We incorporated our in vitro and in vivo experimental results with analysis of publicly available RNA-seq and single nuclei RNA-seq datasets and uncovered the regulation of Mediator subunits in different physiological and temporal contexts. Our experimental results revealed that Mediator subunit expression during myogenesis is highly dynamic. We also discovered unique temporal patterns of Mediator expression in muscle stem cells after injury and during the early regeneration period, suggesting that Mediator subunits may have unique contributions to directing muscle stem cell fate. Although we observed few changes in Mediator subunit expression in aging muscles compared to younger muscles, we uncovered extensive heterogeneity of Mediator subunit expression in dystrophic muscle nuclei, characteristic of chronic muscle degeneration and regeneration cycles. Taken together, our study provides a glimpse of the complex regulation of Mediator subunit expression in the skeletal muscle cell lineage and serves as a springboard for mechanistic studies into the function of individual Mediator subunits in skeletal muscle.
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Affiliation(s)
- Dominic W. Kolonay
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Kristina M. Sattler
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Corinne Strawser
- Department of Pediatrics, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Institute for Genomic Medicine, Nationwide Children’s Hospital, Columbus, OH, United States
| | - Jill Rafael-Fortney
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Maria M. Mihaylova
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH, United States
| | - Katherine E. Miller
- Department of Pediatrics, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Institute for Genomic Medicine, Nationwide Children’s Hospital, Columbus, OH, United States
| | - Christoph Lepper
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Kedryn K. Baskin
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
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Kinyamu HK, Bennett BD, Ward JM, Archer TK. Proteasome Inhibition Reprograms Chromatin Landscape in Breast Cancer. CANCER RESEARCH COMMUNICATIONS 2024; 4:1082-1099. [PMID: 38625038 PMCID: PMC11019832 DOI: 10.1158/2767-9764.crc-23-0476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 02/26/2024] [Accepted: 03/22/2024] [Indexed: 04/17/2024]
Abstract
The 26S proteasome is the major protein degradation machinery in cells. Cancer cells use the proteasome to modulate gene expression networks that promote tumor growth. Proteasome inhibitors have emerged as effective cancer therapeutics, but how they work mechanistically remains unclear. Here, using integrative genomic analysis, we discovered unexpected reprogramming of the chromatin landscape and RNA polymerase II (RNAPII) transcription initiation in breast cancer cells treated with the proteasome inhibitor MG132. The cells acquired dynamic changes in chromatin accessibility at specific genomic loci termed differentially open chromatin regions (DOCR). DOCRs with decreased accessibility were promoter proximal and exhibited unique chromatin architecture associated with divergent RNAPII transcription. Conversely, DOCRs with increased accessibility were primarily distal to transcription start sites and enriched in oncogenic superenhancers predominantly accessible in non-basal breast tumor subtypes. These findings describe the mechanisms by which the proteasome modulates the expression of gene networks intrinsic to breast cancer biology. SIGNIFICANCE Our study provides a strong basis for understanding the mechanisms by which proteasome inhibitors exert anticancer effects. We find open chromatin regions that change during proteasome inhibition, are typically accessible in non-basal breast cancers.
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Affiliation(s)
- H. Karimi Kinyamu
- Chromatin and Gene Expression Section, National Institute of Environmental Health Sciences, Durham, North Carolina
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Durham, North Carolina
- National Institute of Environmental Health Sciences, Durham, North Carolina
| | - Brian D. Bennett
- National Institute of Environmental Health Sciences, Durham, North Carolina
- Integrative Bioinformatics Group, National Institute of Environmental Health Sciences, Durham, North Carolina
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, Durham, North Carolina
| | - James M. Ward
- National Institute of Environmental Health Sciences, Durham, North Carolina
- Integrative Bioinformatics Group, National Institute of Environmental Health Sciences, Durham, North Carolina
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, Durham, North Carolina
| | - Trevor K. Archer
- Chromatin and Gene Expression Section, National Institute of Environmental Health Sciences, Durham, North Carolina
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Durham, North Carolina
- National Institute of Environmental Health Sciences, Durham, North Carolina
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7
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Blomberg J, Tasselius V, Vergara A, Karamat F, Imran QM, Strand Å, Rosvall M, Björklund S. Pseudomonas syringae infectivity correlates to altered transcript and metabolite levels of Arabidopsis mediator mutants. Sci Rep 2024; 14:6771. [PMID: 38514763 PMCID: PMC10958028 DOI: 10.1038/s41598-024-57192-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 03/15/2024] [Indexed: 03/23/2024] Open
Abstract
Rapid metabolic responses to pathogens are essential for plant survival and depend on numerous transcription factors. Mediator is the major transcriptional co-regulator for integration and transmission of signals from transcriptional regulators to RNA polymerase II. Using four Arabidopsis Mediator mutants, med16, med18, med25 and cdk8, we studied how differences in regulation of their transcript and metabolite levels correlate to their responses to Pseudomonas syringae infection. We found that med16 and cdk8 were susceptible, while med25 showed increased resistance. Glucosinolate, phytoalexin and carbohydrate levels were reduced already before infection in med16 and cdk8, but increased in med25, which also displayed increased benzenoids levels. Early after infection, wild type plants showed reduced glucosinolate and nucleoside levels, but increases in amino acids, benzenoids, oxylipins and the phytoalexin camalexin. The Mediator mutants showed altered levels of these metabolites and in regulation of genes encoding key enzymes for their metabolism. At later stage, mutants displayed defective levels of specific amino acids, carbohydrates, lipids and jasmonates which correlated to their infection response phenotypes. Our results reveal that MED16, MED25 and CDK8 are required for a proper, coordinated transcriptional response of genes which encode enzymes involved in important metabolic pathways for Arabidopsis responses to Pseudomonas syringae infections.
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Affiliation(s)
- Jeanette Blomberg
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87, Umeå, Sweden
| | - Viktor Tasselius
- Department of Physics, Umeå University, 901 87, Umeå, Sweden
- Biostatistics, School of Public Health and Community Medicine, Gothenburg University, P.O. Box 463, 405 30, Gothenburg, Sweden
| | | | - Fazeelat Karamat
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87, Umeå, Sweden
| | - Qari Muhammad Imran
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87, Umeå, Sweden
| | - Åsa Strand
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, 901 87, Umeå, Sweden
| | - Martin Rosvall
- Department of Physics, Umeå University, 901 87, Umeå, Sweden
| | - Stefan Björklund
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87, Umeå, Sweden.
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Isozumi N, Sugie K, Mori E. [Biological phase separation in neuromuscular diseases]. Rinsho Shinkeigaku 2023; 63:799-805. [PMID: 37989290 DOI: 10.5692/clinicalneurol.cn-001877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
Biological phase separation refers to the liquid-liquid phase separation of biomolecules such as proteins in cells. Phase separation is driven by low-complexity domains of phase-separating proteins and strictly controlled by regulatory factors. Phase separation has also been found to be disrupted by genetic abnormalities. Abnormal aggregates of causative proteins accumulate in many neuromuscular diseases. In recent years, it has become clear that phase separating proteins are associated with neuromuscular diseases, and that abnormalities in the regulation of phase separation leads to the formation of aggregates. Gains in our knowledge of biological phase separation is gradually elucidating the pathogenesis of neuromuscular diseases.
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Affiliation(s)
| | - Kazuma Sugie
- Department of Neurology, Nara Medical University
| | - Eiichiro Mori
- Department of Future Basic Medicine, Nara Medical University
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Zamanian MY, Golmohammadi M, Nili-Ahmadabadi A, Alameri AA, Al-Hassan M, Alshahrani SH, Hasan MS, Ramírez-Coronel AA, Qasim QA, Heidari M, Verma A. Targeting autophagy with tamoxifen in breast cancer: From molecular mechanisms to targeted therapy. Fundam Clin Pharmacol 2023; 37:1092-1108. [PMID: 37402635 DOI: 10.1111/fcp.12936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/24/2023] [Accepted: 06/13/2023] [Indexed: 07/06/2023]
Abstract
BACKGROUND Tamoxifen (TAM) is often recommended as a first-line treatment for estrogen receptor-positive breast cancer (BC). However, TAM resistance continues to be a medical challenge for BC with hormone receptor positivity. The function of macro-autophagy and autophagy has recently been identified to be altered in BC, which suggests a potential mechanism for TAM resistance. Autophagy is a cellular stress-induced response to preserve cellular homeostasis. Also, therapy-induced autophagy, which is typically cytoprotective and activated in tumor cells, could sometimes be non-protective, cytostatic, or cytotoxic depending on how it is regulated. OBJECTIVE This review explored the literature on the connections between hormonal therapies and autophagy. We investigated how autophagy could develop drug resistance in BC cells. METHODS Scopus, Science Direct, PubMed, and Google Scholar were used to search articles for this study. RESULTS The results demonstrated that protein kinases such as pAMPK, BAX, and p-p70S6K could be a sign of autophagy in developing TAM resistance. According to the study's findings, autophagy plays an important role in BC patients' TAM resistance. CONCLUSION Therefore, by overcoming endocrine resistance in estrogen receptor-positive breast tumors, autophagy inhibition may improve the therapeutic efficacy of TAM.
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Affiliation(s)
- Mohammad Yasin Zamanian
- Department of Physiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
- Department of Pharmacology and Toxicology, School of Pharmacy, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Maryam Golmohammadi
- School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir Nili-Ahmadabadi
- Department of Pharmacology and Toxicology, School of Pharmacy, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Ameer A Alameri
- Department of Chemistry, College of Science, University of Babylon, Babylon, Iraq
| | | | | | - Mohammed Sami Hasan
- Department of Anesthesia Techniques, Al-Mustaqbal University College, Babylon, Iraq
| | - Andrés Alexis Ramírez-Coronel
- Azogues Campus Nursing Career, Health and Behavior Research group (HBR), Psychometry and Ethology Laboratory, Catholic University of Cuenca, Cuenca, Ecuador
- University of Palermo, Buenos Aires, Argentina
- Research Group in Educational Statistics, National University of Education, Azogues, Ecuador
- Epidemiology and Biostatistics Research Group, CES University, Medellín, Colombia
| | | | - Mahsa Heidari
- Department of Biochemistry, Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran
| | - Amita Verma
- Bioorganic and Medicinal Chemistry Research Laboratory, Department of Pharmaceutical Sciences, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagari, India
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Bi W, Bao K, Zhou X, Deng Y, Li X, Zhang J, Lan X, Zhao J, Lu D, Xu Y, Cen Y, Cao R, Xu M, Zhong W, Zhu L. PSMC5 regulates microglial polarization and activation in LPS-induced cognitive deficits and motor impairments by interacting with TLR4. J Neuroinflammation 2023; 20:277. [PMID: 38001534 PMCID: PMC10668523 DOI: 10.1186/s12974-023-02904-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 09/23/2023] [Indexed: 11/26/2023] Open
Abstract
Luteolin is a flavonoid found in high concentrations in celery and green pepper, and acts as a neuroprotectant. PSMC5 (proteasome 26S subunit, ATPase 5) protein levels were reduced after luteolin stimulation in activated microglia. We aimed to determine whether regulating PSMC5 expression could inhibit neuroinflammation, and investigate the underlying mechanisms.BV2 microglia were transfected with siRNA PSMC5 before the addition of LPS (lipopolysaccharide, 1.0 µg/ml) for 24 h in serum free DMEM. A mouse model of LPS-induced cognitive and motor impairment was established to evaluate the neuroprotective effects of shRNA PSMC5. Intracerebroventricular administration of shRNA PSMC5 was commenced 7 days prior to i.p. injection of LPS (750 μg/kg). Treatments and behavioral experiments were performed once daily for 7 consecutive days. Behavioral tests and pathological/biochemical assays were performed to evaluate LPS-induced hippocampal damage. Molecular dynamics simulation was used to confirm the interaction between PSMC5 and TLR4 (Toll-like receptor 4) in LPS-stimulated BV2 microglia. SiRNA PSMC5 inhibited BV2 microglial activation, and suppressed the release of inflammatory factors (IL-1β, COX-2, PGE2, TNF-α, and iNOS) upon after LPS stimulation in BV2 microglia. LPS increased IκB-α and p65 phosphorylation, which was attenuated by siRNA PSMC5. Behavioral tests and pathological/biochemical assays showed that shRNA PSMC5 attenuated LPS-induced cognitive and motor impairments, and restored synaptic ultrastructure and protein levels in mice. ShRNA PSMC5 reduced pro-inflammatory cytokine (TNF-α, IL-1β, PGE2, and NO) levels in the serum and brain, and relevant protein factors (iNOS and COX-2) in the brain. Furthermore, shRNA PSMC5 upregulated the anti-inflammatory mediators interleukin IL-4 and IL-10 in the serum and brain, and promoted a pro-inflammation-to-anti-inflammation phenotype shift in microglial polarization. Mechanistically, shRNA PSMC5 significantly alleviated LPS-induced TLR4 expression. The polarization of LPS-induced microglial pro-inflammation phenotype was abolished by TLR4 inhibitor and in the TLR-4-/- mouse, as in shRNA PSMC5 treatment. PSMC5 interacted with TLR4 via the amino sites Glu284, Met139, Leu127, and Phe283. PSMC5 site mutations attenuated neuroinflammation and reduced pro-inflammatory factors by reducing TLR4-related effects, thereby reducing TLR4-mediated MyD88 (myeloid differentiation factor 88)-dependent activation of NF-κB. PSMC5 could be an important therapeutic target for treatment of neurodegenerative diseases involving neuroinflammation-associated cognitive deficits and motor impairments induced by microglial activation.
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Affiliation(s)
- Wei Bi
- Department of Neurology, The First Affiliated Hospital of Jinan University, No. 613, West Huangpu Avenue, Guangzhou, 510630, China
- Clinical Neuoscience Institute, The First Affiliated Hospital of Jinan University, No. 613, West Huangpu Avenue, Guangzhou, 510630, China
| | - Keyao Bao
- Department of Pathophysiology, School of Medicine, Jinan University, No. 601, West Huangpu Avenue, Guangzhou, 510632, China
| | - Xinqi Zhou
- Department of Pathophysiology, School of Medicine, Jinan University, No. 601, West Huangpu Avenue, Guangzhou, 510632, China
| | - Yihui Deng
- Central Laboratory of the First Affiliated Hospital of Jinan University, No. 613, West Huangpu Avenue, Guangzhou, 510630, China
| | - Xiaoting Li
- Department of Neurology, The First Affiliated Hospital of Jinan University, No. 613, West Huangpu Avenue, Guangzhou, 510630, China
| | - Jiawei Zhang
- Department of Pathophysiology, School of Medicine, Jinan University, No. 601, West Huangpu Avenue, Guangzhou, 510632, China
| | - Xin Lan
- Department of Pathophysiology, School of Medicine, Jinan University, No. 601, West Huangpu Avenue, Guangzhou, 510632, China
| | - Jiayi Zhao
- Department of Pathophysiology, School of Medicine, Jinan University, No. 601, West Huangpu Avenue, Guangzhou, 510632, China
| | - Daxiang Lu
- Department of Pathophysiology, School of Medicine, Jinan University, No. 601, West Huangpu Avenue, Guangzhou, 510632, China
| | - Yezi Xu
- Department of Neurology, The First Affiliated Hospital of Jinan University, No. 613, West Huangpu Avenue, Guangzhou, 510630, China
| | - Yanmei Cen
- Department of Neurology, The First Affiliated Hospital of Jinan University, No. 613, West Huangpu Avenue, Guangzhou, 510630, China
| | - Rui Cao
- Department of Neurology, The First Affiliated Hospital of Jinan University, No. 613, West Huangpu Avenue, Guangzhou, 510630, China
| | - Mengyang Xu
- Department of Biology, Jinan University, No. 601, West Huangpu Avenue, Guangzhou, 510632, China
| | - Wenbin Zhong
- Department of Biology, Jinan University, No. 601, West Huangpu Avenue, Guangzhou, 510632, China.
| | - Lihong Zhu
- Department of Pathophysiology, School of Medicine, Jinan University, No. 601, West Huangpu Avenue, Guangzhou, 510632, China.
- Guangzhou Key Laboratory for Germ-free Animals and Microbiota Application, No. 601, West Huangpu Avenue, Guangzhou, 510632, China.
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11
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Kinyamu HK, Bennett BD, Ward JM, Archer T. Proteasome inhibition reprograms chromatin landscape in breast cancer. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.13.562284. [PMID: 37904968 PMCID: PMC10614768 DOI: 10.1101/2023.10.13.562284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
The 26S proteasome is the major protein degradation machinery in cells. Cancer cells use the proteasome to modulate gene expression networks that promote tumor growth. Proteasome inhibitors have emerged as effective cancer therapeutics, but how they work mechanistically remains unclear. Here, using integrative genomic analysis, we discovered unexpected reprogramming of the chromatin landscape and RNAPII transcription initiation in breast cancer cells treated with the proteasome inhibitor MG132. The cells acquired dynamic changes in chromatin accessibility at specific genomic loci termed Differentially Open Chromatin Regions (DOCRs). DOCRs with decreased accessibility were promoter proximal and exhibited unique chromatin architecture associated with divergent RNAPII transcription. Conversely, DOCRs with increased accessibility were primarily distal to transcription start sites and enriched in oncogenic super enhancers predominantly accessible in non-basal breast tumor subtypes. These findings describe the mechanisms by which the proteasome modulates the expression of gene networks intrinsic to breast cancer biology. Highlights Proteasome inhibition uncovers de novo Differential Open Chromatin Regions (DOCRs) in breast cancer cells. Proteasome inhibitor sensitive promoters exhibit a distinctive chromatin architecture with discrete transcription initiation patterns.Proteasome inhibition reprograms accessibility of super enhancers.Proteasome inhibitor sensitive super enhancers distinguish basal from non-basal breast cancer subtypes.
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12
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Moreno RY, Juetten KJ, Panina SB, Butalewicz JP, Floyd BM, Venkat Ramani MK, Marcotte EM, Brodbelt JS, Zhang YJ. Distinctive interactomes of RNA polymerase II phosphorylation during different stages of transcription. iScience 2023; 26:107581. [PMID: 37664589 PMCID: PMC10470302 DOI: 10.1016/j.isci.2023.107581] [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: 05/11/2023] [Revised: 06/28/2023] [Accepted: 08/04/2023] [Indexed: 09/05/2023] Open
Abstract
During eukaryotic transcription, RNA polymerase II undergoes dynamic post-translational modifications on the C-terminal domain (CTD) of the largest subunit, generating an information-rich PTM landscape that transcriptional regulators bind. The phosphorylation of Ser5 and Ser2 of CTD heptad occurs spatiotemporally with the transcriptional stages, recruiting different transcriptional regulators to Pol II. To delineate the protein interactomes at different transcriptional stages, we reconstructed phosphorylation patterns of the CTD at Ser5 and Ser2 in vitro. Our results showed that distinct protein interactomes are recruited to RNA polymerase II at different stages of transcription by the phosphorylation of Ser2 and Ser5 of the CTD heptads. In particular, we characterized calcium homeostasis endoplasmic reticulum protein (CHERP) as a regulator bound by phospho-Ser2 heptad. Pol II association with CHERP recruits an accessory splicing complex whose loss results in broad changes in alternative splicing events. Our results shed light on the PTM-coded recruitment process that coordinates transcription.
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Affiliation(s)
| | - Kyle J. Juetten
- Department of Chemistry, University of Texas, Austin, TX, USA
| | - Svetlana B. Panina
- Department of Molecular Biosciences, University of Texas, Austin, TX, USA
| | | | - Brendan M. Floyd
- Department of Molecular Biosciences, University of Texas, Austin, TX, USA
| | | | - Edward M. Marcotte
- Department of Molecular Biosciences, University of Texas, Austin, TX, USA
| | | | - Y. Jessie Zhang
- Department of Molecular Biosciences, University of Texas, Austin, TX, USA
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13
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Nguyen MC, Wang D, Klein BJ, Chen Y, Kutateladze TG. Differences and similarities in recognition of co-factors by Taf14. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2023; 1866:194961. [PMID: 37482120 DOI: 10.1016/j.bbagrm.2023.194961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 07/13/2023] [Accepted: 07/17/2023] [Indexed: 07/25/2023]
Abstract
Taf14 is a subunit of multiple fundamental complexes implicated in transcriptional regulation and DNA damage repair in yeast cells. Here, we investigate the association of Taf14 with the consensus sequence present in other subunits of these complexes and describe the mechanistic features that affect this association. We demonstrate that the precise molecular mechanisms and biological outcomes underlying the Taf14 interactions depend on the accessibility of binding interfaces, the ability to recognize other ligands, and a degree of sensitivity to temperature and chemical and osmotic stresses. Our findings aid in a better understanding of how the distribution of Taf14 among the complexes is mediated.
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Affiliation(s)
- Minh Chau Nguyen
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Duo Wang
- State Key Laboratory of Molecular Biology, National Center for Protein Science Shanghai, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Brianna J Klein
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Yong Chen
- State Key Laboratory of Molecular Biology, National Center for Protein Science Shanghai, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China.
| | - Tatiana G Kutateladze
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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14
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Rengachari S, Schilbach S, Cramer P. Mediator structure and function in transcription initiation. Biol Chem 2023; 404:829-837. [PMID: 37078249 DOI: 10.1515/hsz-2023-0158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 04/06/2023] [Indexed: 04/21/2023]
Abstract
Recent advances in cryo-electron microscopy have led to multiple structures of Mediator in complex with the RNA polymerase II (Pol II) transcription initiation machinery. As a result we now hold in hands near-complete structures of both yeast and human Mediator complexes and have a better understanding of their interactions with the Pol II pre-initiation complex (PIC). Herein, we provide a summary of recent achievements and discuss their implications for future studies of Mediator and its role in gene regulation.
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Affiliation(s)
- Srinivasan Rengachari
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany
| | - Sandra Schilbach
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany
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15
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Wu Q, Tong C, Chen Z, Huang S, Zhao X, Hong H, Li J, Feng M, Wang H, Xu M, Yan Y, Cui H, Shen D, Ai G, Xu Y, Li J, Zhang H, Huang C, Zhang Z, Dong S, Wang X, Zhu M, Dinesh-Kumar SP, Tao X. NLRs derepress MED10b- and MED7-mediated repression of jasmonate-dependent transcription to activate immunity. Proc Natl Acad Sci U S A 2023; 120:e2302226120. [PMID: 37399403 PMCID: PMC10334756 DOI: 10.1073/pnas.2302226120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 05/23/2023] [Indexed: 07/05/2023] Open
Abstract
Plant intracellular nucleotide-binding domain, leucine-rich repeat-containing receptors (NLRs) activate a robust immune response upon detection of pathogen effectors. How NLRs induce downstream immune defense genes remains poorly understood. The Mediator complex plays a central role in transducing signals from gene-specific transcription factors to the transcription machinery for gene transcription/activation. In this study, we demonstrate that MED10b and MED7 of the Mediator complex mediate jasmonate-dependent transcription repression, and coiled-coil NLRs (CNLs) in Solanaceae modulate MED10b/MED7 to activate immunity. Using the tomato CNL Sw-5b, which confers resistance to tospovirus, as a model, we found that the CC domain of Sw-5b directly interacts with MED10b. Knockout/down of MED10b and other subunits including MED7 of the middle module of Mediator activates plant defense against tospovirus. MED10b was found to directly interact with MED7, and MED7 directly interacts with JAZ proteins, which function as transcriptional repressors of jasmonic acid (JA) signaling. MED10b-MED7-JAZ together can strongly repress the expression of JA-responsive genes. The activated Sw-5b CC interferes with the interaction between MED10b and MED7, leading to the activation of JA-dependent defense signaling against tospovirus. Furthermore, we found that CC domains of various other CNLs including helper NLR NRCs from Solanaceae modulate MED10b/MED7 to activate defense against different pathogens. Together, our findings reveal that MED10b/MED7 serve as a previously unknown repressor of jasmonate-dependent transcription repression and are modulated by diverse CNLs in Solanaceae to activate the JA-specific defense pathways.
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Affiliation(s)
- Qian Wu
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
| | - Cong Tong
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
| | - Zhengqiang Chen
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
| | - Shen Huang
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
| | - Xiaohui Zhao
- Salinity Agriculture Research Laboratory, Jiangsu Coastal Area Institute of Agricultural Sciences, Yancheng224002, P. R. China
| | - Hao Hong
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
| | - Jia Li
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
| | - Mingfeng Feng
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
| | - Huiyuan Wang
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
- Institute of Biotechnology, Zhejiang University, Hangzhou310058, P. R. China
| | - Min Xu
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
| | - Yuling Yan
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
| | - Hongmin Cui
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
| | - Danyu Shen
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
| | - Gan Ai
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
| | - Yi Xu
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
| | - Junming Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing100081, P. R. China
| | - Hui Zhang
- Institute of Horticulture Science, Shanghai Academy of Agricultural Sciences, Shanghai201403, P. R. China
| | - Changjun Huang
- Yunnan Academy of Tobacco Agricultural Sciences, Key Laboratory of Tobacco Biotechnological Breeding, National Tobacco Genetic Engineering Research Center, Kunming650021, P. R. China
| | - Zhongkai Zhang
- Yunnan Provincial Key Laboratory of Agri-Biotechnology, Institute of Biotechnology and Genetic Resources, Yunnan Academy of Agricultural Sciences, Kunming, Yunnan650223, P. R. China
| | - Suomeng Dong
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
| | - Xuan Wang
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
| | - Min Zhu
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
| | - Savithramma P. Dinesh-Kumar
- Department of Plant Biology and The Genome Center College of Biological Sciences, University of California, Davis, CA95616
| | - Xiaorong Tao
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing210095, P. R. China
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16
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Pal S, Biswas D. Promoter-proximal regulation of gene transcription: Key factors involved and emerging role of general transcription factors in assisting productive elongation. Gene 2023:147571. [PMID: 37331491 DOI: 10.1016/j.gene.2023.147571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/02/2023] [Accepted: 06/13/2023] [Indexed: 06/20/2023]
Abstract
The pausing of RNA polymerase II (Pol II) at the promoter-proximal sites is a key rate-limiting step in gene expression. Cells have dedicated a specific set of proteins that sequentially establish pause and then release the Pol II from promoter-proximal sites. A well-controlled pausing and subsequent release of Pol II is crucial for thefine tuning of expression of genes including signal-responsive and developmentally-regulated ones. The release of paused Pol II broadly involves its transition from initiation to elongation. In this review article, we will discuss the phenomenon of Pol II pausing, the underlying mechanism, and also the role of different known factors, with an emphasis on general transcription factors, involved in this overall regulation. We will further discuss some recent findings suggesting a possible role (underexplored) of initiation factors in assisting the transition of transcriptionally-engaged paused Pol II into productive elongation.
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Affiliation(s)
- Sujay Pal
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata - 32, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Debabrata Biswas
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata - 32, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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17
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Shapulatov U, van Zanten M, van Hoogdalem M, Meisenburg M, van Hall A, Kappers I, Fasano C, Facella P, Loh CC, Perrella G, van der Krol A. The Mediator complex subunit MED25 interacts with HDA9 and PIF4 to regulate thermomorphogenesis. PLANT PHYSIOLOGY 2023; 192:582-600. [PMID: 36537119 PMCID: PMC10152658 DOI: 10.1093/plphys/kiac581] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 10/27/2022] [Accepted: 11/01/2022] [Indexed: 05/03/2023]
Abstract
Thermomorphogenesis is, among other traits, characterized by enhanced hypocotyl elongation due to the induction of auxin biosynthesis genes like YUCCA8 by transcription factors, most notably PHYTOCHROME INTERACTING FACTOR 4 (PIF4). Efficient binding of PIF4 to the YUCCA8 locus under warmth depends on HISTONE DEACETYLASE 9 (HDA9) activity, which mediates histone H2A.Z depletion at the YUCCA8 locus. However, HDA9 lacks intrinsic DNA-binding capacity, and how HDA9 is recruited to YUCCA8, and possibly other PIF4-target sites, is currently not well understood. The Mediator complex functions as a bridge between transcription factors bound to specific promoter sequences and the basal transcription machinery containing RNA polymerase II. Mutants of Mediator component Mediator25 (MED25) exhibit reduced hypocotyl elongation and reduced expression of YUCCA8 at 27°C. In line with a proposed role for MED25 in thermomorphogenesis in Arabidopsis (Arabidopsis thaliana), we demonstrated an enhanced association of MED25 to the YUCCA8 locus under warmth and interaction of MED25 with both PIF4 and HDA9. Genetic analysis confirmed that MED25 and HDA9 operate in the same pathway. Intriguingly, we also showed that MED25 destabilizes HDA9 protein. Based on our findings, we propose that MED25 recruits HDA9 to the YUCCA8 locus by binding to both PIF4 and HDA9.
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Affiliation(s)
- Umidjon Shapulatov
- Laboratory of Plant Physiology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
- Temasek Life Science Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore
| | - Martijn van Zanten
- Plant Stress Resilience, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Mark van Hoogdalem
- Laboratory of Plant Physiology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Mara Meisenburg
- Laboratory of Plant Physiology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Alexander van Hall
- Laboratory of Plant Physiology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Iris Kappers
- Laboratory of Plant Physiology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Carlo Fasano
- Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Trisaia Research Centre, S.S. Ionica, km 419.5, 75026 Rotondella (Matera), Italy
| | - Paolo Facella
- Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Trisaia Research Centre, S.S. Ionica, km 419.5, 75026 Rotondella (Matera), Italy
| | - Chi Cheng Loh
- Temasek Life Science Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore
| | - Giorgio Perrella
- Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Trisaia Research Centre, S.S. Ionica, km 419.5, 75026 Rotondella (Matera), Italy
| | - Alexander van der Krol
- Laboratory of Plant Physiology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
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18
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Schofield JA, Hahn S. Broad compatibility between yeast UAS elements and core promoters and identification of promoter elements that determine cofactor specificity. Cell Rep 2023; 42:112387. [PMID: 37058407 PMCID: PMC10567116 DOI: 10.1016/j.celrep.2023.112387] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 01/30/2023] [Accepted: 03/28/2023] [Indexed: 04/15/2023] Open
Abstract
Three classes of yeast protein-coding genes are distinguished by their dependence on the transcription cofactors TFIID, SAGA, and Mediator (MED) Tail, but whether this dependence is determined by the core promoter, upstream activating sequences (UASs), or other gene features is unclear. Also unclear is whether UASs can broadly activate transcription from the different promoter classes. Here, we measure transcription and cofactor specificity for thousands of UAS-core promoter combinations and find that most UASs broadly activate promoters regardless of regulatory class, while few display strong promoter specificity. However, matching UASs and promoters from the same gene class is generally important for optimal expression. We find that sensitivity to rapid depletion of MED Tail or SAGA is dependent on the identity of both UAS and core promoter, while dependence on TFIID localizes to only the promoter. Finally, our results suggest the role of TATA and TATA-like promoter sequences in MED Tail function.
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Affiliation(s)
- Jeremy A Schofield
- Basic Sciences Division, Fred Hutchinson Cancer Center, 1100 Fairview Avenue N, Seattle, WA 98105, USA
| | - Steven Hahn
- Basic Sciences Division, Fred Hutchinson Cancer Center, 1100 Fairview Avenue N, Seattle, WA 98105, USA.
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19
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Gorbea Colón JJ, Palao L, Chen SF, Kim HJ, Snyder L, Chang YW, Tsai KL, Murakami K. Structural basis of a transcription pre-initiation complex on a divergent promoter. Mol Cell 2023; 83:574-588.e11. [PMID: 36731470 PMCID: PMC10162435 DOI: 10.1016/j.molcel.2023.01.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 11/28/2022] [Accepted: 01/06/2023] [Indexed: 02/04/2023]
Abstract
Most eukaryotic promoter regions are divergently transcribed. As the RNA polymerase II pre-initiation complex (PIC) is intrinsically asymmetric and responsible for transcription in a single direction, it is unknown how divergent transcription arises. Here, the Saccharomyces cerevisiae Mediator complexed with a PIC (Med-PIC) was assembled on a divergent promoter and analyzed by cryoelectron microscopy. The structure reveals two distinct Med-PICs forming a dimer through the Mediator tail module, induced by a homodimeric activator protein localized near the dimerization interface. The tail dimer is associated with ∼80-bp upstream DNA, such that two flanking core promoter regions are positioned and oriented in a suitable form for PIC assembly in opposite directions. Also, cryoelectron tomography visualized the progress of the PIC assembly on the two core promoter regions, providing direct evidence for the role of the Med-PIC dimer in divergent transcription.
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Affiliation(s)
- Jose J Gorbea Colón
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Leon Palao
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shin-Fu Chen
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Hee Jong Kim
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Laura Snyder
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yi-Wei Chang
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Kuang-Lei Tsai
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
| | - Kenji Murakami
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Penn Center for Genome Integrity, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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20
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Lambert É, Puwakdandawa K, Tao YF, Robert F. From structure to molecular condensates: emerging mechanisms for Mediator function. FEBS J 2023; 290:286-309. [PMID: 34698446 DOI: 10.1111/febs.16250] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/15/2021] [Accepted: 10/25/2021] [Indexed: 02/05/2023]
Abstract
Mediator is a large modular protein assembly whose function as a coactivator of transcription is conserved in all eukaryotes. The Mediator complex can integrate and relay signals from gene-specific activators bound at enhancers to activate the general transcription machinery located at promoters. It has thus been described as a bridge between these elements during initiation of transcription. Here, we review recent studies on Mediator relating to its structure, gene specificity and general requirement, roles in chromatin architecture as well as novel concepts involving phase separation and transcriptional bursting. We revisit the mechanism of action of Mediator and ultimately put forward models for its mode of action in gene activation.
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Affiliation(s)
- Élie Lambert
- Institut de recherches cliniques de Montréal, Canada
| | | | - Yi Fei Tao
- Institut de recherches cliniques de Montréal, Canada
| | - François Robert
- Institut de recherches cliniques de Montréal, Canada.,Département de Médecine, Faculté de Médecine, Université de Montréal, Canada
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21
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Warfield L, Donczew R, Mahendrawada L, Hahn S. Yeast Mediator facilitates transcription initiation at most promoters via a Tail-independent mechanism. Mol Cell 2022; 82:4033-4048.e7. [PMID: 36208626 PMCID: PMC9637718 DOI: 10.1016/j.molcel.2022.09.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 05/12/2022] [Accepted: 09/13/2022] [Indexed: 11/06/2022]
Abstract
Mediator (MED) is a conserved factor with important roles in basal and activated transcription. Here, we investigate the genome-wide roles of yeast MED by rapid depletion of its activator-binding domain (Tail) and monitoring changes in nascent transcription. Rapid Tail depletion surprisingly reduces transcription from only a small subset of genes. At most of these Tail-dependent genes, in unperturbed conditions, MED is detected at both the UASs and promoters. In contrast, at most Tail-independent genes, we find MED primarily at promoters but not at the UASs. These results suggest that MED Tail and activator-mediated MED recruitment regulates only a small subset of genes. Furthermore, we define three classes of genes that differ in PIC assembly pathways and the requirements for MED Tail, SAGA, TFIID, and BET factors Bdf1/2. Our combined results have broad implications for the roles of MED, other coactivators, and mechanisms of transcriptional regulation at different gene classes.
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Affiliation(s)
- Linda Warfield
- Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Mailstop A1-162, Seattle, WA 98109, USA
| | - Rafal Donczew
- Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Mailstop A1-162, Seattle, WA 98109, USA
| | - Lakshmi Mahendrawada
- Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Mailstop A1-162, Seattle, WA 98109, USA
| | - Steven Hahn
- Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Mailstop A1-162, Seattle, WA 98109, USA.
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22
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Richter WF, Nayak S, Iwasa J, Taatjes DJ. The Mediator complex as a master regulator of transcription by RNA polymerase II. Nat Rev Mol Cell Biol 2022; 23:732-749. [PMID: 35725906 PMCID: PMC9207880 DOI: 10.1038/s41580-022-00498-3] [Citation(s) in RCA: 77] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2022] [Indexed: 02/08/2023]
Abstract
The Mediator complex, which in humans is 1.4 MDa in size and includes 26 subunits, controls many aspects of RNA polymerase II (Pol II) function. Apart from its size, a defining feature of Mediator is its intrinsic disorder and conformational flexibility, which contributes to its ability to undergo phase separation and to interact with a myriad of regulatory factors. In this Review, we discuss Mediator structure and function, with emphasis on recent cryogenic electron microscopy data of the 4.0-MDa transcription preinitiation complex. We further discuss how Mediator and sequence-specific DNA-binding transcription factors enable enhancer-dependent regulation of Pol II function at distal gene promoters, through the formation of molecular condensates (or transcription hubs) and chromatin loops. Mediator regulation of Pol II reinitiation is also discussed, in the context of transcription bursting. We propose a working model for Mediator function that combines experimental results and theoretical considerations related to enhancer-promoter interactions, which reconciles contradictory data regarding whether enhancer-promoter communication is direct or indirect. We conclude with a discussion of Mediator's potential as a therapeutic target and of future research directions.
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Affiliation(s)
- William F Richter
- Department of Biochemistry, University of Colorado, Boulder, CO, USA
| | - Shraddha Nayak
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Janet Iwasa
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Dylan J Taatjes
- Department of Biochemistry, University of Colorado, Boulder, CO, USA.
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23
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Shrestha HK, Fichman Y, Engle NL, Tschaplinski TJ, Mittler R, Dixon RA, Hettich RL, Barros J, Abraham PE. Multi-omic characterization of bifunctional peroxidase 4-coumarate 3-hydroxylase knockdown in Brachypodium distachyon provides insights into lignin modification-associated pleiotropic effects. FRONTIERS IN PLANT SCIENCE 2022; 13:908649. [PMID: 36247563 PMCID: PMC9554711 DOI: 10.3389/fpls.2022.908649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 09/09/2022] [Indexed: 06/16/2023]
Abstract
A bifunctional peroxidase enzyme, 4-coumarate 3-hydroxylase (C3H/APX), provides a parallel route to the shikimate shunt pathway for the conversion of 4-coumarate to caffeate in the early steps of lignin biosynthesis. Knockdown of C3H/APX (C3H/APX-KD) expression has been shown to reduce the lignin content in Brachypodium distachyon. However, like many other lignin-modified plants, C3H/APX-KDs show unpredictable pleiotropic phenotypes, including stunted growth, delayed senescence, and reduced seed yield. A system-wide level understanding of altered biological processes in lignin-modified plants can help pinpoint the lignin-modification associated growth defects to benefit future studies aiming to negate the yield penalty. Here, a multi-omic approach was used to characterize molecular changes resulting from C3H/APX-KD associated lignin modification and negative growth phenotype in Brachypodium distachyon. Our findings demonstrate that C3H/APX knockdown in Brachypodium stems substantially alters the abundance of enzymes implicated in the phenylpropanoid biosynthetic pathway and disrupt cellular redox homeostasis. Moreover, it elicits plant defense responses associated with intracellular kinases and phytohormone-based signaling to facilitate growth-defense trade-offs. A deeper understanding along with potential targets to mitigate the pleiotropic phenotypes identified in this study could aid to increase the economic feasibility of lignocellulosic biofuel production.
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Affiliation(s)
- Him K. Shrestha
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Genome Science and Technology, University of Tennessee-Knoxville, Knoxville, TN, United States
| | - Yosef Fichman
- Division of Plant Sciences and Interdisciplinary Plant Group, University of Missouri, Columbia, MO, United States
| | - Nancy L. Engle
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | | | - Ron Mittler
- Division of Plant Sciences and Interdisciplinary Plant Group, University of Missouri, Columbia, MO, United States
| | - Richard A. Dixon
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Robert L. Hettich
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Jaime Barros
- Division of Plant Sciences and Interdisciplinary Plant Group, University of Missouri, Columbia, MO, United States
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Paul E. Abraham
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
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24
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MED16 Promotes Tumour Progression and Tamoxifen Sensitivity by Modulating Autophagy through the mTOR Signalling Pathway in ER-Positive Breast Cancer. Life (Basel) 2022; 12:life12101461. [PMID: 36294896 PMCID: PMC9604881 DOI: 10.3390/life12101461] [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: 08/11/2022] [Revised: 09/11/2022] [Accepted: 09/16/2022] [Indexed: 12/02/2022] Open
Abstract
Recent studies have shown that the mediator complex (MED) plays a vital role in tumorigenesis and development, but the role of MED16 (mediator complex subunit 16) in breast cancer (BC) is not clear. Increasing evidence has shown that the mTOR pathway is important for tumour progression and therapy. In this study, we demonstrated that the mTOR signalling pathway is regulated by the expression level of MED16 in ER+ breast cancer. With the analysis of bioinformatics data and clinical specimens, we revealed an elevated expression of MED16 in luminal subtype tumours. We found that MED16 knockdown significantly inhibited cell proliferation and promoted G1 phase cell cycle arrest in ER+ BC cell lines. Downregulation of MED16 markedly reduced the sensitivity of ER+ BC cells to tamoxifen and increased the stemness and autophagy of ER+ BC cells. Bioinformatic analysis of similar genes to MED16 were mainly enriched in autophagy, endocrine therapy and mTOR signalling pathways, and the inhibition of mTOR-mediated autophagy restored sensitivity to tamoxifen by MED16 downregulation in ER+ BC cells. These results suggest an important role of MED16 in the regulation of tamoxifen sensitivity in ER+ BC cells, crosstalk between the mTOR signalling pathway-induced autophagy, and together, with the exploration of tamoxifen resistance, may indicate a new therapy option for endocrine therapy-resistant patients.
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25
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Agrawal R, Sharma M, Dwivedi N, Maji S, Thakur P, Junaid A, Fajkus J, Laxmi A, Thakur JK. MEDIATOR SUBUNIT17 integrates jasmonate and auxin signaling pathways to regulate thermomorphogenesis. PLANT PHYSIOLOGY 2022; 189:2259-2280. [PMID: 35567489 PMCID: PMC9342970 DOI: 10.1093/plphys/kiac220] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 04/20/2022] [Indexed: 05/16/2023]
Abstract
Plant adjustment to environmental changes involves complex crosstalk between extrinsic and intrinsic cues. In the past two decades, extensive research has elucidated the key roles of PHYTOCHROME-INTERACTING FACTOR4 (PIF4) and the phytohormone auxin in thermomorphogenesis. In this study, we identified a previously unexplored role of jasmonate (JA) signaling components, the Mediator complex, and their integration with auxin signaling during thermomorphogenesis in Arabidopsis (Arabidopsis thaliana). Warm temperature induces expression of JA signaling genes including MYC2, but, surprisingly, this transcriptional activation is not JA dependent. Warm temperature also promotes accumulation of the JA signaling receptor CORONATINE INSENSITIVE1 (COI1) and degradation of the JA signaling repressor JASMONATE-ZIM-DOMAIN PROTEIN9, which probably leads to de-repression of MYC2, enabling it to contribute to the expression of MEDIATOR SUBUNIT17 (MED17). In response to warm temperature, MED17 occupies the promoters of thermosensory genes including PIF4, YUCCA8 (YUC8), INDOLE-3-ACETIC ACID INDUCIBLE19 (IAA19), and IAA29. Moreover, MED17 facilitates enrichment of H3K4me3 on the promoters of PIF4, YUC8, IAA19, and IAA29 genes. Interestingly, both occupancy of MED17 and enrichment of H3K4me3 on these thermomorphogenesis-related promoters are dependent on PIF4 (or PIFs). Altered accumulation of COI1 under warm temperature in the med17 mutant suggests the possibility of a feedback mechanism. Overall, this study reveals the role of the Mediator complex as an integrator of JA and auxin signaling pathways during thermomorphogenesis.
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Affiliation(s)
- Rekha Agrawal
- Plant Mediator Lab, National Institute of Plant Genome Research, New Delhi 110067, India
| | - Mohan Sharma
- Signalling Lab, National Institute of Plant Genome Research, New Delhi 110067, India
| | - Nidhi Dwivedi
- Plant Mediator Lab, National Institute of Plant Genome Research, New Delhi 110067, India
| | - Sourobh Maji
- Plant Mediator Lab, National Institute of Plant Genome Research, New Delhi 110067, India
| | - Pallabi Thakur
- Plant Mediator Lab, National Institute of Plant Genome Research, New Delhi 110067, India
| | - Alim Junaid
- Plant Mediator Lab, National Institute of Plant Genome Research, New Delhi 110067, India
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Ashverya Laxmi
- Signalling Lab, National Institute of Plant Genome Research, New Delhi 110067, India
| | - Jitendra K Thakur
- Plant Mediator Lab, National Institute of Plant Genome Research, New Delhi 110067, India
- Plant Transcription Regulation Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
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26
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Respiratory Syncytial virus NS1 protein targets the transactivator binding domain of MED25. J Mol Biol 2022; 434:167763. [PMID: 35907573 DOI: 10.1016/j.jmb.2022.167763] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 06/28/2022] [Accepted: 07/21/2022] [Indexed: 11/20/2022]
Abstract
Human RSV is the leading cause of infantile bronchiolitis in the world and one of the major causes of childhood deaths in resource-poor settings. It is a major unmet target for vaccines and anti-viral drugs. Respiratory syncytial virus has evolved a unique strategy to evade host immune response by coding for two non-structural proteins NS1 and NS2. Recently it was shown that in infected cells, nuclear NS1 could be involved in transcription regulation of host genes linked to innate immune response, via interactions with chromatin and the Mediator complex. Here we identified the MED25 Mediator subunit as an NS1 interactor in a yeast two-hybrid screen. We demonstrate that NS1 directly interacts with MED25 in vitro and in cellula, and that this interaction involves the MED25 transactivator binding ACID domain on the one hand, and the C-terminal α3 helix of NS1, with an additional contribution of the globular domain of NS1, on the other hand. By NMR we show that the NS1 α3 sequence primarily binds to the MED25 ACID H2 face, similarly to the α-helical transactivation domains (TADs) of transcription regulators such as Herpex simplex VP16 and ATF6α, a master regulator of ER stress response activated upon viral infection. Moreover, we found out that the NS1 could compete with ATF6α TAD for binding to MED25. These findings point to a mechanism of NS1 interfering with innate immune response by impairing recruitment by cellular TADs of the Mediator via MED25 and hence transcription of specific genes by RNA polymerase II.
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27
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Mattingly M, Seidel C, Muñoz S, Hao Y, Zhang Y, Wen Z, Florens L, Uhlmann F, Gerton JL. Mediator recruits the cohesin loader Scc2 to RNA Pol II-transcribed genes and promotes sister chromatid cohesion. Curr Biol 2022; 32:2884-2896.e6. [PMID: 35654035 PMCID: PMC9286023 DOI: 10.1016/j.cub.2022.05.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 04/07/2022] [Accepted: 05/09/2022] [Indexed: 11/25/2022]
Abstract
The ring-like cohesin complex plays an essential role in chromosome segregation, organization, and double-strand break repair through its ability to bring two DNA double helices together. Scc2 (NIPBL in humans) together with Scc4 functions as the loader of cohesin onto chromosomes. Chromatin adapters such as the RSC complex facilitate the localization of the Scc2-Scc4 cohesin loader. Here, we identify a broad range of Scc2-chromatin protein interactions that are evolutionarily conserved and reveal a role for one complex, Mediator, in the recruitment of the cohesin loader. We identified budding yeast Med14, a subunit of the Mediator complex, as a high copy suppressor of poor growth in Scc2 mutant strains. Physical and genetic interactions between Scc2 and Mediator are functionally substantiated in direct recruitment and cohesion assays. Depletion of Med14 results in defective sister chromatid cohesion and the decreased binding of Scc2 at RNA Pol II-transcribed genes. Previous work has suggested that Mediator, Nipbl, and cohesin connect enhancers and promoters of active mammalian genes. Our studies suggest an evolutionarily conserved fundamental role for Mediator in the direct recruitment of Scc2 to RNA Pol II-transcribed genes.
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Affiliation(s)
- Mark Mattingly
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Chris Seidel
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Sofía Muñoz
- Chromosome Segregation Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Yan Hao
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Ying Zhang
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Zhihui Wen
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Laurence Florens
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Jennifer L Gerton
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA; Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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28
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Morse RH. Function and dynamics of the Mediator complex: novel insights and new frontiers. Transcription 2022; 13:39-52. [PMID: 35708525 PMCID: PMC9467533 DOI: 10.1080/21541264.2022.2085502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The Mediator complex was discovered in the early 1990s as a biochemically fractionated factor from yeast extracts that was necessary for activator-stimulated transcriptional activation to be observed in in vitro transcription assays. The structure of this large, multi-protein complex is now understood in great detail, and novel genetic approaches have provided rich insights into its dynamics during transcriptional activation and the mechanism by which it facilitates activated transcription. Here I review recent findings and unanswered questions regarding Mediator dynamics, the roles of individual subunits, and differences between its function in yeast and metazoan cells.
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Affiliation(s)
- Randall H Morse
- Wadsworth Center, New York State Department of Health, Albany, NY, United States.,Department of Biomedical Sciences, University at Albany School of Public Health, Albany, NY, United States
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29
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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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30
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Role of the Mediator Complex and MicroRNAs in Breast Cancer Etiology. Genes (Basel) 2022; 13:genes13020234. [PMID: 35205279 PMCID: PMC8871970 DOI: 10.3390/genes13020234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/17/2022] [Accepted: 01/19/2022] [Indexed: 12/16/2022] Open
Abstract
Transcriptional coactivators play a key role in RNA polymerase II transcription and gene regulation. One of the most important transcriptional coactivators is the Mediator (MED) complex, which is an evolutionary conserved large multiprotein complex. MED transduces the signal between DNA-bound transcriptional activators (gene-specific transcription factors) to the RNA polymerase II transcription machinery to activate transcription. It is known that MED plays an essential role in ER-mediated gene expression mainly through the MED1 subunit, since estrogen receptor (ER) can interact with MED1 by specific protein–protein interactions; therefore, MED1 plays a fundamental role in ER-positive breast cancer (BC) etiology. Additionally, other MED subunits also play a role in BC etiology. On the other hand, microRNAs (miRNAs) are a family of small non-coding RNAs, which can regulate gene expression at the post-transcriptional level by binding in a sequence-specific fashion at the 3′ UTR of the messenger RNA. The miRNAs are also important factors that influence oncogenic signaling in BC by acting as both tumor suppressors and oncogenes. Moreover, miRNAs are involved in endocrine therapy resistance of BC, specifically to tamoxifen, a drug that is used to target ER signaling. In metazoans, very little is known about the transcriptional regulation of miRNA by the MED complex and less about the transcriptional regulation of miRNAs involved in BC initiation and progression. Recently, it has been shown that MED1 is able to regulate the transcription of the ER-dependent miR-191/425 cluster promoting BC cell proliferation and migration. In this review, we will discuss the role of MED1 transcriptional coactivator in the etiology of BC and in endocrine therapy-resistance of BC and also the contribution of other MED subunits to BC development, progression and metastasis. Lastly, we identified miRNAs that potentially can regulate the expression of MED subunits.
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31
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Tan W, Peng S, Li Z, Zhang R, Xiao Y, Chen X, Zhu J, Li B, Lv X. Identification of Therapeutic Targets and Prognostic Biomarkers among Genes from the Mediator Complex Family in the Hepatocellular Carcinoma Tumour-Immune Microenvironment. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2022; 2022:2021613. [PMID: 35069777 PMCID: PMC8776440 DOI: 10.1155/2022/2021613] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/30/2021] [Accepted: 12/07/2021] [Indexed: 12/21/2022]
Abstract
BACKGROUND Hepatocellular carcinoma (HCC) is predominant among all types of primary liver cancers characterised by high morbidity and mortality. Genes in the mediator complex (MED) family are engaged in the tumour-immune microenvironment and function as regulatory hubs mediating carcinogenesis and progression across diverse cancer types. Whereas research studies have been conducted to examine the mechanisms in several cancers, studies that systematically focused on the therapeutic and prognostic values of MED in patients with HCC are limited. METHODS The online databases ONCOMINE, GEPIA, UALCAN, GeneMANIA, cBioPortal, OmicStudio, STING, Metascape, and TIMER were used in this study. RESULTS The transcriptional levels of all members of the MED family in HCC presented an aberrant high expression pattern. Significant correlations were found between the MED1, MED6, MED8, MED10, MED12, MED15, MED17, MED19, MED20, MED21, MED22, MED23, MED24, MED25, MED26, and MED27 expression levels and the pathological stage in the patients with HCC. The patients with high expression levels of MED6, MED8, MED10, MED17, MED19, MED20, MED21, MED22, MED24, and MED25 were significantly associated with poor prognosis. Functional enrichment analysis revealed that the members of the MED family were mainly enriched in the nucleobase-containing compound catabolic process, regulation of chromosome organisation, and transcriptional regulation by TP53. Significant correlations were found between the MED6, MED8, MED10, MED17, MED19, MED20, MED21, MED22, MED24, and MED25 expression levels and all types of immune cells (B cells, CD8+ T cells, CD4+ T cells, macrophages, neutrophils, and dendritic cells). B cells and MED8 were independent predictors of overall survival. We found significant correlations between the somatic copy number alterations of the MED6, MED8, MED10, MED20, MED21, MED22, MED24, and MED25 molecules and the abundance of immune infiltrates. CONCLUSIONS Our study delineated a thorough landscape to investigate the therapeutic and prognostic potentials of the MED family for HCC cases, which yielded promising results for the development of immunotherapeutic drugs and construction of a prognostic stratification model.
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Affiliation(s)
- Wei Tan
- Department of Hepatobiliary and Pancreatic Surgery, Lishui Central Hospital, Fifth Affiliated Hospital of Wenzhou Medical College, Lishui City, Zhejiang Province 323000, China
| | - Shuai Peng
- Department of Radiology, The First Affiliated Hospital of Guangxi Medical University, Nanning City, Guangxi Zhuang Autonomous Region 530021, China
| | - Zhuokai Li
- Department of Hepatobiliary and Pancreatic Surgery, Lishui Central Hospital, Fifth Affiliated Hospital of Wenzhou Medical College, Lishui City, Zhejiang Province 323000, China
| | - Ruiqian Zhang
- Department of Hepatobiliary and Pancreatic Surgery, Lishui Central Hospital, Fifth Affiliated Hospital of Wenzhou Medical College, Lishui City, Zhejiang Province 323000, China
| | - Yangrui Xiao
- Department of Radiology, Lishui Central Hospital, Fifth Affiliated Hospital of Wenzhou Medical College, Lishui City, Zhejiang Province 323000, China
| | - Xiao Chen
- Department of Radiology, Lishui Central Hospital, Fifth Affiliated Hospital of Wenzhou Medical College, Lishui City, Zhejiang Province 323000, China
| | - Jinde Zhu
- Department of Hepatobiliary and Pancreatic Surgery, Lishui Central Hospital, Fifth Affiliated Hospital of Wenzhou Medical College, Lishui City, Zhejiang Province 323000, China
| | - Bingrong Li
- Department of Radiology, Lishui Central Hospital, Fifth Affiliated Hospital of Wenzhou Medical College, Lishui City, Zhejiang Province 323000, China
| | - Xinliang Lv
- Department of Hepatobiliary and Pancreatic Surgery, Lishui Central Hospital, Fifth Affiliated Hospital of Wenzhou Medical College, Lishui City, Zhejiang Province 323000, China
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32
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Stellato M, Santini D, Cursano MC, Foderaro S, Tonini G, Procopio G. Bone metastases from urothelial carcinoma. The dark side of the moon. J Bone Oncol 2021; 31:100405. [PMID: 34934613 DOI: 10.1016/j.jbo.2021.100405] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 11/01/2021] [Accepted: 11/24/2021] [Indexed: 10/19/2022] Open
Abstract
Bone metastases are common in genitourinary cancers, but they are underreported and not well researched. Synchronous bone metastases occur in 1.39-5.5% of bladder cancer patients, while 30-40% of cases are metachronous. Bone morphogenetic proteins (BMPs) play a key role in regulating proliferation, migration and invasion of tumor cells in bone microenvironment of bone metastases from metastatic urothelial carcinoma (mUC). Bone metastases represent a poor prognostic factor due to high morbidity and mortality correlated to skeletal-related events (SREs). The incidence rate of SREs in bladder, renal pelvis, and ureteral cancer varies from 39 to 68%. Radiotherapy is the most frequent treatment for SREs. The early use of bone targeted therapies (BTT), zoledronic acid and denosumab, improves SREs incidence and morbidity and it seems to improve overall survival (OS). To date, several new agents (immunotherapy and targeted drugs) demonstrated efficacy in mUC. However, subgroup analysis for bone metastases is often not available, due to difficulties in analysing bone samples, non-RECIST lesions and delay in systemic treatment due to SREs that limit the enrolment of bone mUC patients in clinical trials. Larger solid tumor studies that included UC patients are the main source of data for the management of mUC patients with bone metastases. For these patients, multidisciplinary approach should be preferred, involving orthopaedics, radiotherapists and rehabilitation to improve outcome and quality of life. New prospective trials should characterize clinical and molecular features of patients with bone metastases and the impact of new drugs on this poor prognostic metastatic site.
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Affiliation(s)
- Marco Stellato
- Department of Medical Oncology, Campus Bio-Medico University of Rome, Rome, Italy.,Meet-URO: Italian Network For Research In Urologic-Oncology, Italy
| | - Daniele Santini
- Department of Medical Oncology, Campus Bio-Medico University of Rome, Rome, Italy.,Meet-URO: Italian Network For Research In Urologic-Oncology, Italy
| | - Maria Concetta Cursano
- Department of Medical Oncology, Campus Bio-Medico University of Rome, Rome, Italy.,Meet-URO: Italian Network For Research In Urologic-Oncology, Italy
| | - Simone Foderaro
- Department of Medical Oncology, Campus Bio-Medico University of Rome, Rome, Italy.,Meet-URO: Italian Network For Research In Urologic-Oncology, Italy
| | - Giuseppe Tonini
- Department of Medical Oncology, Campus Bio-Medico University of Rome, Rome, Italy.,Meet-URO: Italian Network For Research In Urologic-Oncology, Italy
| | - Giuseppe Procopio
- Medical Oncology Department, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.,Meet-URO: Italian Network For Research In Urologic-Oncology, Italy
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33
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Dixit G, Prabhu A. The pleiotropic peroxisome proliferator activated receptors: Regulation and therapeutics. Exp Mol Pathol 2021; 124:104723. [PMID: 34822814 DOI: 10.1016/j.yexmp.2021.104723] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/02/2021] [Accepted: 11/15/2021] [Indexed: 02/07/2023]
Abstract
The Peroxisome proliferator-activated receptors (PPARs) are key regulators of metabolic events in our body. Owing to their implication in maintenance of homeostasis, both PPAR agonists and antagonists assume therapeutic significance. Understanding the molecular mechanisms of each of the PPAR isotypes in the healthy body and during disease is crucial to exploiting their full therapeutic potential. This article is an attempt to present a rational analysis of the multifaceted therapeutic effects and underlying mechanisms of isotype-specific PPAR agonists, dual PPAR agonists, pan PPAR agonists as well as PPAR antagonists. A holistic understanding of the mechanistic dimensions of these key metabolic regulators will guide future efforts to identify novel molecules in the realm of metabolic, inflammatory and immunotherapeutic diseases.
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Affiliation(s)
- Gargi Dixit
- Department of Pharmaceutical Chemistry & Quality Assurance, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, Mumbai, India
| | - Arati Prabhu
- Department of Pharmaceutical Chemistry & Quality Assurance, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, Mumbai, India.
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34
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Zhang L, Song Y, Liu K, Gong F. The tomato Mediator subunit MED8 positively regulates plant response to Botrytis cinerea. JOURNAL OF PLANT PHYSIOLOGY 2021; 266:153533. [PMID: 34601339 DOI: 10.1016/j.jplph.2021.153533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 09/21/2021] [Accepted: 09/21/2021] [Indexed: 06/13/2023]
Abstract
The Mediator complex acts as a bridge between specific transcription factors and the RNA polymerase II transcriptional machinery and plays a central role in plant immunity. Biological induction of plant resistance against pathogens requires endogenous hormone jasmonic acid (JA) and involves profound transcriptional changes controlled by the key transcription factor MYC2. Arabidopsis thaliana Mediator subunit 25 (AtMED25) regulates JA-dependent defense response through interacting with MYC2. Here, we report that the tomato (Solanum lycopersicum, Sl) Mediator subunit 8 (SlMED8) is another essential component in JA-dependent defense response. The transcript levels of SlMED8 could not be affected by treatment with MeJA, SA, ABA, and mechanical wounding. Yeast two-hybrid assays showed that SlMED8 could interact with itself, SlMYC2, and SlMED25, respectively. In addition, ectopic overexpression of SlMED8 complemented the late flowering and pathogen hypersensitivity phenotypes of Arabidopsis med8 mutant. Overexpression of SlMED8 rendered transgenic plants higher tolerance to necrotrophic pathogen Botrytis cinerea. Meanwhile, SlMED8 antisense plants displayed compromised resistance to Botrytis cinerea. Consistent with this, differential expression levels of several JA-responsive genes were detected within the transgenic plants. Overall, our results identified an important control point in the regulation of the JA signaling pathway within the transcriptional machinery.
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Affiliation(s)
- Lili Zhang
- Shanghai Key Lab of Protected Horticultural Technology; Horticultural Research Institute, Shanghai Academy of Agricultural Sciences, 2901 Beidi Rd, Shanghai, 201106, PR China.
| | - Yunpeng Song
- Shanghai Key Lab of Protected Horticultural Technology; Horticultural Research Institute, Shanghai Academy of Agricultural Sciences, 2901 Beidi Rd, Shanghai, 201106, PR China.
| | - Kaige Liu
- Shanghai Key Lab of Protected Horticultural Technology; Horticultural Research Institute, Shanghai Academy of Agricultural Sciences, 2901 Beidi Rd, Shanghai, 201106, PR China.
| | - Fanrong Gong
- Shanghai Key Lab of Protected Horticultural Technology; Horticultural Research Institute, Shanghai Academy of Agricultural Sciences, 2901 Beidi Rd, Shanghai, 201106, PR China.
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35
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Petrenko N, Struhl K. Comparison of transcriptional initiation by RNA polymerase II across eukaryotic species. eLife 2021; 10:e67964. [PMID: 34515029 PMCID: PMC8463073 DOI: 10.7554/elife.67964] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 09/10/2021] [Indexed: 01/17/2023] Open
Abstract
The preinitiation complex (PIC) for transcriptional initiation by RNA polymerase (Pol) II is composed of general transcription factors that are highly conserved. However, analysis of ChIP-seq datasets reveals kinetic and compositional differences in the transcriptional initiation process among eukaryotic species. In yeast, Mediator associates strongly with activator proteins bound to enhancers, but it transiently associates with promoters in a form that lacks the kinase module. In contrast, in human, mouse, and fly cells, Mediator with its kinase module stably associates with promoters, but not with activator-binding sites. This suggests that yeast and metazoans differ in the nature of the dynamic bridge of Mediator between activators and Pol II and the composition of a stable inactive PIC-like entity. As in yeast, occupancies of TATA-binding protein (TBP) and TBP-associated factors (Tafs) at mammalian promoters are not strictly correlated. This suggests that within PICs, TFIID is not a monolithic entity, and multiple forms of TBP affect initiation at different classes of genes. TFIID in flies, but not yeast and mammals, interacts strongly at regions downstream of the initiation site, consistent with the importance of downstream promoter elements in that species. Lastly, Taf7 and the mammalian-specific Med26 subunit of Mediator also interact near the Pol II pause region downstream of the PIC, but only in subsets of genes and often not together. Species-specific differences in PIC structure and function are likely to affect how activators and repressors affect transcriptional activity.
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Affiliation(s)
- Natalia Petrenko
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical SchoolBostonUnited States
| | - Kevin Struhl
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical SchoolBostonUnited States
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36
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Cevher MA. Reconstitution of Pol II (G) responsive form of the human Mediator complex. Turk J Biol 2021; 45:253-261. [PMID: 34377050 PMCID: PMC8313941 DOI: 10.3906/biy-2009-12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 04/16/2021] [Indexed: 01/15/2023] Open
Abstract
RNA polymerase II (Pol II) is a 12 subunit protein complex from yeast to human that is required for gene expression. Gdown1 containing Pol II [Pol II (G)] is a special form of Pol II that is catalytically inactive and heavily depends on the 30-subunit Mediator complex for its activator and basal dependent function in vitro. Here we report for the first time, the identification and the generation of a 15-subunit human Mediator complex via the novel multibac baculovirus expression system that is fully responsive to Pol II (G). Our results show complete recovery of Pol II (G) dependent transcription both with full 30-subunit Mediator and also with 15-subunit recombinant Mediator that we synthesized. Moreover, we also show that the recombinant Mediator interacts with Pol II (G) as well. These results enlighten us towards understanding how a certain population of Pol II that is involved in selected gene regulation is activated by Mediator complex.
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Affiliation(s)
- Murat Alper Cevher
- Department of Molecular Biology and Genetics, Faculty of Science, Bilkent University, Ankara Turkey.,Visiting Assistant Professor, Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York USA
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37
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Tang M, Pei G, Su D, Wang C, Feng X, Srivastava M, Chen Z, Zhao Z, Chen J. Genome-wide CRISPR screens reveal cyclin C as synthetic survival target of BRCA2. Nucleic Acids Res 2021; 49:7476-7491. [PMID: 34197614 PMCID: PMC8287926 DOI: 10.1093/nar/gkab540] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/04/2021] [Accepted: 06/23/2021] [Indexed: 01/15/2023] Open
Abstract
Poly (ADP-ribose) polymerase inhibitor (PARPi)-based therapies initially reduce tumor burden but eventually lead to acquired resistance in cancer patients with BRCA1 or BRCA2 mutation. To understand the potential PARPi resistance mechanisms, we performed whole-genome CRISPR screens to discover genetic alterations that change the gene essentiality in cells with inducible depletion of BRCA2. We identified that several RNA Polymerase II transcription Mediator complex components, especially Cyclin C (CCNC) as synthetic survival targets upon BRCA2 loss. Total mRNA sequencing demonstrated that loss of CCNC could activate the transforming growth factor (TGF)-beta signaling pathway and extracellular matrix (ECM)-receptor interaction pathway, however the inhibition of these pathways could not reverse cell survival in BRCA2 depleted CCNC-knockout cells, indicating that the activation of these pathways is not required for the resistance. Moreover, we showed that the improved survival is not due to restoration of homologous recombination repair although decreased DNA damage signaling was observed. Interestingly, loss of CCNC could restore replication fork stability in BRCA2 deficient cells, which may contribute to PARPi resistance. Taken together, our data reveal CCNC as a critical genetic determinant upon BRCA2 loss of function, which may help the development of novel therapeutic strategies that overcome PARPi resistance.
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Affiliation(s)
- Mengfan Tang
- Department of Experimental Radiation Oncology, Unit 1052, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Guangsheng Pei
- Center for Precision Health, School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Dan Su
- Department of Experimental Radiation Oncology, Unit 1052, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Chao Wang
- Department of Experimental Radiation Oncology, Unit 1052, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xu Feng
- Department of Experimental Radiation Oncology, Unit 1052, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Mrinal Srivastava
- Department of Experimental Radiation Oncology, Unit 1052, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Zhen Chen
- Department of Experimental Radiation Oncology, Unit 1052, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Zhongming Zhao
- Center for Precision Health, School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA.,Human Genetics Center, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Junjie Chen
- Department of Experimental Radiation Oncology, Unit 1052, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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38
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Baek I, Friedman LJ, Gelles J, Buratowski S. Single-molecule studies reveal branched pathways for activator-dependent assembly of RNA polymerase II pre-initiation complexes. Mol Cell 2021; 81:3576-3588.e6. [PMID: 34384542 DOI: 10.1016/j.molcel.2021.07.025] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 07/08/2021] [Accepted: 07/21/2021] [Indexed: 01/24/2023]
Abstract
RNA polymerase II (RNA Pol II) transcription reconstituted from purified factors suggests pre-initiation complexes (PICs) can assemble by sequential incorporation of factors at the TATA box. However, these basal transcription reactions are generally independent of activators and co-activators. To study PIC assembly under more realistic conditions, we used single-molecule microscopy to visualize factor dynamics during activator-dependent reactions in nuclear extracts. Surprisingly, RNA Pol II, TFIIF, and TFIIE can pre-assemble on enhancer-bound activators before loading into PICs, and multiple RNA Pol II complexes can bind simultaneously to create a localized cluster. Unlike TFIIF and TFIIE, TFIIH binding is singular and dependent on the basal promoter. Activator-tethered factors exhibit dwell times on the order of seconds. In contrast, PICs can persist on the order of minutes in the absence of nucleotide triphosphates, although TFIIE remains unexpectedly dynamic even after TFIIH incorporation. Our kinetic measurements lead to a new branched model for activator-dependent PIC assembly.
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Affiliation(s)
- Inwha Baek
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Larry J Friedman
- Department of Biochemistry, Brandeis University, Waltham, MA 02454, USA
| | - Jeff Gelles
- Department of Biochemistry, Brandeis University, Waltham, MA 02454, USA.
| | - Stephen Buratowski
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
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39
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Sun F, Sun T, Kronenberg M, Tan X, Huang C, Carey MF. The Pol II preinitiation complex (PIC) influences Mediator binding but not promoter-enhancer looping. Genes Dev 2021; 35:1175-1189. [PMID: 34301767 PMCID: PMC8336890 DOI: 10.1101/gad.348471.121] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 06/24/2021] [Indexed: 02/05/2023]
Abstract
Knowledge of how Mediator and TFIID cross-talk contributes to promoter-enhancer (P-E) communication is important for elucidating the mechanism of enhancer function. We conducted an shRNA knockdown screen in murine embryonic stem cells to identify the functional overlap between Mediator and TFIID subunits on gene expression. Auxin-inducible degrons were constructed for TAF12 and MED4, the subunits eliciting the greatest overlap. Degradation of TAF12 led to a dramatic genome-wide decrease in gene expression accompanied by destruction of TFIID, loss of Pol II preinitiation complex (PIC) at promoters, and significantly decreased Mediator binding to promoters and enhancers. Interestingly, loss of the PIC elicited only a mild effect on P-E looping by promoter capture Hi-C (PCHi-C). Degradation of MED4 had a minor effect on Mediator integrity but led to a consistent twofold loss in gene expression, decreased binding of Pol II to Mediator, and decreased recruitment of Pol II to the promoters, but had no effect on the other PIC components. PCHi-C revealed no consistent effect of MED4 degradation on P-E looping. Collectively, our data show that TAF12 and MED4 contribute mechanistically in different ways to P-E communication but neither factor appears to directly control P-E looping, thereby dissociating P-E communication from physical looping.
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Affiliation(s)
- Fei Sun
- Department of Biological Chemistry, David Geffen School of Medicine at University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Terrence Sun
- Department of Biological Chemistry, David Geffen School of Medicine at University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Michael Kronenberg
- Department of Biological Chemistry, David Geffen School of Medicine at University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Xianglong Tan
- Department of Biological Chemistry, David Geffen School of Medicine at University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Chengyang Huang
- Center for Neurobiology, Shantou University Medical College, Shantou 515041, China
| | - Michael F Carey
- Department of Biological Chemistry, David Geffen School of Medicine at University of California at Los Angeles, Los Angeles, California 90095, USA
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40
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González-Jiménez A, Campos A, Navarro F, Clemente-Blanco A, Calvo O. Regulation of Eukaryotic RNAPs Activities by Phosphorylation. Front Mol Biosci 2021; 8:681865. [PMID: 34250017 PMCID: PMC8268151 DOI: 10.3389/fmolb.2021.681865] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 06/07/2021] [Indexed: 01/11/2023] Open
Abstract
Evolutionarily conserved kinases and phosphatases regulate RNA polymerase II (RNAPII) transcript synthesis by modifying the phosphorylation status of the carboxyl-terminal domain (CTD) of Rpb1, the largest subunit of RNAPII. Proper levels of Rpb1-CTD phosphorylation are required for RNA co-transcriptional processing and to coordinate transcription with other nuclear processes, such as chromatin remodeling and histone modification. Whether other RNAPII subunits are phosphorylated and influences their role in gene expression is still an unanswered question. Much less is known about RNAPI and RNAPIII phosphorylation, whose subunits do not contain functional CTDs. However, diverse studies have reported that several RNAPI and RNAPIII subunits are susceptible to phosphorylation. Some of these phosphorylation sites are distributed within subunits common to all three RNAPs whereas others are only shared between RNAPI and RNAPIII. This suggests that the activities of all RNAPs might be finely modulated by phosphorylation events and raises the idea of a tight coordination between the three RNAPs. Supporting this view, the transcription by all RNAPs is regulated by signaling pathways that sense different environmental cues to adapt a global RNA transcriptional response. This review focuses on how the phosphorylation of RNAPs might regulate their function and we comment on the regulation by phosphorylation of some key transcription factors in the case of RNAPI and RNAPIII. Finally, we discuss the existence of possible common mechanisms that could coordinate their activities.
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Affiliation(s)
- Araceli González-Jiménez
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Universidad de Salamanca, Salamanca, Spain
| | - Adrián Campos
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Universidad de Salamanca, Salamanca, Spain
| | - Francisco Navarro
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Jaén, Spain.,Centro de Estudios Avanzados en Aceite de Oliva y Olivar, Universidad de Jaén, Jaén, Spain
| | - Andrés Clemente-Blanco
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Universidad de Salamanca, Salamanca, Spain
| | - Olga Calvo
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Universidad de Salamanca, Salamanca, Spain
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41
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Leydon AR, Wang W, Gala HP, Gilmour S, Juarez-Solis S, Zahler ML, Zemke JE, Zheng N, Nemhauser JL. Repression by the Arabidopsis TOPLESS corepressor requires association with the core mediator complex. eLife 2021; 10:66739. [PMID: 34075876 PMCID: PMC8203292 DOI: 10.7554/elife.66739] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 05/31/2021] [Indexed: 02/06/2023] Open
Abstract
The plant corepressor TOPLESS (TPL) is recruited to a large number of loci that are selectively induced in response to developmental or environmental cues, yet the mechanisms by which it inhibits expression in the absence of these stimuli are poorly understood. Previously, we had used the N-terminus of Arabidopsis thaliana TPL to enable repression of a synthetic auxin response circuit in Saccharomyces cerevisiae (yeast). Here, we leveraged the yeast system to interrogate the relationship between TPL structure and function, specifically scanning for repression domains. We identified a potent repression domain in Helix 8 located within the CRA domain, which directly interacted with the Mediator middle module subunits Med21 and Med10. Interactions between TPL and Mediator were required to fully repress transcription in both yeast and plants. In contrast, we found that multimer formation, a conserved feature of many corepressors, had minimal influence on the repression strength of TPL.
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Affiliation(s)
| | - Wei Wang
- Department of Pharmacology, Seattle, United States
| | - Hardik P Gala
- Department of Biology, University of Washington, Seattle, United States
| | - Sabrina Gilmour
- Department of Biology, University of Washington, Seattle, United States
| | | | - Mollye L Zahler
- Department of Biology, University of Washington, Seattle, United States
| | - Joseph E Zemke
- Department of Biology, University of Washington, Seattle, United States
| | - Ning Zheng
- Department of Pharmacology, Seattle, United States.,Howard Hughes Medical Institute, University of Washington, Seattle, United States
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42
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Youn DY, Xiaoli AM, Zong H, Okada J, Liu L, Pessin J, Pessin JE, Yang F. The Mediator complex kinase module is necessary for fructose regulation of liver glycogen levels through induction of glucose-6-phosphatase catalytic subunit (G6pc). Mol Metab 2021; 48:101227. [PMID: 33812059 PMCID: PMC8099662 DOI: 10.1016/j.molmet.2021.101227] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/23/2021] [Accepted: 03/26/2021] [Indexed: 11/30/2022] Open
Abstract
OBJECTIVE Liver glycogen levels are dynamic and highly regulated by nutrient availability as the levels decrease during fasting and are restored during the feeding cycle. However, feeding in the presence of fructose in water suppresses glycogen accumulation in the liver by upregulating the expression of the glucose-6-phosphatase catalytic subunit (G6pc) gene, although the exact mechanism is unknown. We generated liver-specific knockout MED13 mice that lacked the transcriptional Mediator complex kinase module to examine its effect on the transcriptional activation of inducible target gene expression, such as the ChREBP- and FOXO1-dependent control of the G6pc gene promoter. METHODS The relative changes in liver expression of lipogenic and gluconeogenic genes as well as glycogen levels were examined in response to feeding standard low-fat laboratory chow supplemented with water or water containing sucrose or fructose in control (Med13fl/fl) and liver-specific MED13 knockout (MED13-LKO) mice. RESULTS Although MED13 deficiency had no significant effect on constitutive gene expression, all the dietary inducible gene transcripts were significantly reduced despite the unchanged insulin sensitivity in the MED13-LKO mice compared to that in the control mice. G6pc gene transcription displayed the most significant difference between the Med13 fl/fl and MED13-LKO mice, particularly when fed fructose. Following fasting that depleted liver glycogen, feeding induced the restoration of glycogen levels except in the presence of fructose. MED13 deficiency rescued the glycogen accumulation defect in the presence of fructose. This resulted from the suppression of G6pc expression and thus G6PC enzymatic activity. Among two transcriptional factors that regulate G6pc gene expression, FOXO1 binding to the G6pc promoter was not affected, whereas ChREBP binding was dramatically reduced in MED13-LKO hepatocytes. In addition, there was a marked suppression of FOXO1 and ChREBP-β transcriptional activities in MED13-LKO hepatocytes. CONCLUSIONS Taken together, our data suggest that the kinase module of the Mediator complex is necessary for the transcriptional activation of metabolic genes such as G6pc and has an important role in regulating glycogen levels in the liver through altering transcription factor binding and activity at the G6pc promoter.
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Affiliation(s)
- Dou Yeon Youn
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Alus M Xiaoli
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Haihong Zong
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Junichi Okada
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Li Liu
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Jacob Pessin
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Jeffrey E Pessin
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
| | - Fajun Yang
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
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43
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Vodnala M, Choi EB, Fong YW. Low complexity domains, condensates, and stem cell pluripotency. World J Stem Cells 2021; 13:416-438. [PMID: 34136073 PMCID: PMC8176841 DOI: 10.4252/wjsc.v13.i5.416] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 04/20/2021] [Accepted: 04/28/2021] [Indexed: 02/06/2023] Open
Abstract
Biological reactions require self-assembly of factors in the complex cellular milieu. Recent evidence indicates that intrinsically disordered, low-complexity sequence domains (LCDs) found in regulatory factors mediate diverse cellular processes from gene expression to DNA repair to signal transduction, by enriching specific biomolecules in membraneless compartments or hubs that may undergo liquid-liquid phase separation (LLPS). In this review, we discuss how embryonic stem cells take advantage of LCD-driven interactions to promote cell-specific transcription, DNA damage response, and DNA repair. We propose that LCD-mediated interactions play key roles in stem cell maintenance and safeguarding genome integrity.
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Affiliation(s)
- Munender Vodnala
- Department of Medicine, Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, United States
| | - Eun-Bee Choi
- Department of Medicine, Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, United States
| | - Yick W Fong
- Department of Medicine, Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, United States
- Harvard Stem Cell Institute, Cambridge, MA 02138, United States.
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44
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Chen X, Yin X, Li J, Wu Z, Qi Y, Wang X, Liu W, Xu Y. Structures of the human Mediator and Mediator-bound preinitiation complex. Science 2021; 372:science.abg0635. [DOI: 10.1126/science.abg0635] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 03/15/2021] [Accepted: 04/27/2021] [Indexed: 12/18/2022]
Abstract
The 1.3-megadalton transcription factor IID (TFIID) is required for preinitiation complex (PIC) assembly and RNA polymerase II (Pol II)–mediated transcription initiation on almost all genes. The 26-subunit Mediator stimulates transcription and cyclin-dependent kinase 7 (CDK7)–mediated phosphorylation of the Pol II C-terminal domain (CTD). We determined the structures of human Mediator in the Tail module–extended (at near-atomic resolution) and Tail-bent conformations and structures of TFIID-based PIC-Mediator (76 polypeptides, ~4.1 megadaltons) in four distinct conformations. PIC-Mediator assembly induces concerted reorganization (Head-tilting and Middle-down) of Mediator and creates a Head-Middle sandwich, which stabilizes two CTD segments and brings CTD to CDK7 for phosphorylation; this suggests a CTD-gating mechanism favorable for phosphorylation. The TFIID-based PIC architecture modulates Mediator organization and TFIIH stabilization, underscoring the importance of TFIID in orchestrating PIC-Mediator assembly.
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Affiliation(s)
- Xizi Chen
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Xiaotong Yin
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Jiabei Li
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Zihan Wu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Yilun Qi
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Xinxin Wang
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Weida Liu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Yanhui Xu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
- International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, China, Department of Systems Biology for Medicine, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China
- Human Phenome Institute, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200433, China
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45
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Enhancer rewiring in tumors: an opportunity for therapeutic intervention. Oncogene 2021; 40:3475-3491. [PMID: 33934105 DOI: 10.1038/s41388-021-01793-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/30/2021] [Accepted: 04/12/2021] [Indexed: 02/06/2023]
Abstract
Enhancers are cis-regulatory sequences that fine-tune expression of their target genes in a spatiotemporal manner. They are recognized by sequence-specific transcription factors, which in turn recruit transcriptional coactivators that facilitate transcription by promoting assembly and activation of the basal transcriptional machinery. Their functional importance is underscored by the fact that they are often the target of genetic and nongenetic events in human disease that disrupt their sequence, interactome, activation potential, and/or chromatin environment. Dysregulation of transcription and addiction to transcriptional effectors that interact with and modulate enhancer activity are common features of cancer cells and are amenable to therapeutic intervention. Here, we discuss the current knowledge on enhancer biology, the broad spectrum of mechanisms that lead to their malfunction in tumor cells, and recent progress in developing drugs that efficaciously target their dependencies.
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46
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Structure of the human Mediator–RNA polymerase II pre-initiation complex. Nature 2021; 594:129-133. [DOI: 10.1038/s41586-021-03555-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/14/2021] [Indexed: 12/25/2022]
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47
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van Eeuwen T, Li T, Kim HJ, Gorbea Colón JJ, Parker MI, Dunbrack RL, Garcia BA, Tsai KL, Murakami K. Structure of TFIIK for phosphorylation of CTD of RNA polymerase II. SCIENCE ADVANCES 2021; 7:eabd4420. [PMID: 33827808 PMCID: PMC8026125 DOI: 10.1126/sciadv.abd4420] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 02/05/2021] [Indexed: 06/12/2023]
Abstract
During transcription initiation, the general transcription factor TFIIH marks RNA polymerase II by phosphorylating Ser5 of the carboxyl-terminal domain (CTD) of Rpb1, which is followed by extensive modifications coupled to transcription elongation, mRNA processing, and histone dynamics. We have determined a 3.5-Å resolution cryo-electron microscopy (cryo-EM) structure of the TFIIH kinase module (TFIIK in yeast), which is composed of Kin28, Ccl1, and Tfb3, yeast homologs of CDK7, cyclin H, and MAT1, respectively. The carboxyl-terminal region of Tfb3 was lying at the edge of catalytic cleft of Kin28, where a conserved Tfb3 helix served to stabilize the activation loop in its active conformation. By combining the structure of TFIIK with the previous cryo-EM structure of the preinitiation complex, we extend the previously proposed model of the CTD path to the active site of TFIIK.
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Affiliation(s)
- Trevor van Eeuwen
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tao Li
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Hee Jong Kim
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Epigenetics Institute, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jose J Gorbea Colón
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mitchell I Parker
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
- Molecular and Cell Biology and Genetics Program, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - Roland L Dunbrack
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Benjamin A Garcia
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Epigenetics Institute, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kuang-Lei Tsai
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
| | - Kenji Murakami
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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48
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Chen X, Qi Y, Wu Z, Wang X, Li J, Zhao D, Hou H, Li Y, Yu Z, Liu W, Wang M, Ren Y, Li Z, Yang H, Xu Y. Structural insights into preinitiation complex assembly on core promoters. Science 2021; 372:science.aba8490. [PMID: 33795473 DOI: 10.1126/science.aba8490] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 02/01/2021] [Accepted: 03/25/2021] [Indexed: 12/24/2022]
Abstract
Transcription factor IID (TFIID) recognizes core promoters and supports preinitiation complex (PIC) assembly for RNA polymerase II (Pol II)-mediated eukaryotic transcription. We determined the structures of human TFIID-based PIC in three stepwise assembly states and revealed two-track PIC assembly: stepwise promoter deposition to Pol II and extensive modular reorganization on track I (on TATA-TFIID-binding element promoters) versus direct promoter deposition on track II (on TATA-only and TATA-less promoters). The two tracks converge at an ~50-subunit holo PIC in identical conformation, whereby TFIID stabilizes PIC organization and supports loading of cyclin-dependent kinase (CDK)-activating kinase (CAK) onto Pol II and CAK-mediated phosphorylation of the Pol II carboxyl-terminal domain. Unexpectedly, TBP of TFIID similarly bends TATA box and TATA-less promoters in PIC. Our study provides structural visualization of stepwise PIC assembly on highly diversified promoters.
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Affiliation(s)
- Xizi Chen
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Yilun Qi
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Zihan Wu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Xinxin Wang
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Jiabei Li
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Dan Zhao
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Haifeng Hou
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Yan Li
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Zishuo Yu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Weida Liu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Mo Wang
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Yulei Ren
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Ze Li
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Huirong Yang
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Yanhui Xu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China. .,The International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, China, Department of Systems Biology for Medicine, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China.,Human Phenome Institute, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200433, China
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49
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Huang C, Xu R, Liégeois S, Chen D, Li Z, Ferrandon D. Differential Requirements for Mediator Complex Subunits in Drosophila melanogaster Host Defense Against Fungal and Bacterial Pathogens. Front Immunol 2021; 11:478958. [PMID: 33746938 PMCID: PMC7977287 DOI: 10.3389/fimmu.2020.478958] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 12/29/2020] [Indexed: 01/08/2023] Open
Abstract
The humoral immune response to bacterial or fungal infections in Drosophila relies largely on a transcriptional response mediated by the Toll and Immune deficiency NF-κB pathways. Antimicrobial peptides are potent effectors of these pathways and allow the organism to attack invading pathogens. Dorsal-related Immune Factor (DIF), a transcription factor regulated by the Toll pathway, is required in the host defense against fungal and some Gram-positive bacterial infections. The Mediator complex is involved in the initiation of transcription of most RNA polymerase B (PolB)-dependent genes by forming a functional bridge between transcription factors bound to enhancer regions and the gene promoter region and then recruiting the PolB pre-initiation complex. Mediator is formed by several modules that each comprises several subunits. The Med17 subunit of the head module of Mediator has been shown to be required for the expression of Drosomycin, which encodes a potent antifungal peptide, by binding to DIF. Thus, Mediator is expected to mediate the host defense against pathogens controlled by the Toll pathway-dependent innate immune response. Here, we first focus on the Med31 subunit of the middle module of Mediator and find that it is required in host defense against Aspergillus fumigatus, Enterococcus faecalis, and injected but not topically-applied Metarhizium robertsii. Thus, host defense against M. robertsii requires Dif but not necessarily Med31 in the two distinct infection models. The induction of some Toll-pathway-dependent genes is decreased after a challenge of Med31 RNAi-silenced flies with either A. fumigatus or E. faecalis, while these flies exhibit normal phagocytosis and melanization. We have further tested most Mediator subunits using RNAi by monitoring their survival after challenges to several other microbial infections known to be fought off through DIF. We report that the host defense against specific pathogens involves a distinct set of Mediator subunits with only one subunit for C. glabrata or Erwinia carotovora carotovora, at least one for M. robertsii or a somewhat extended repertoire for A. fumigatus (at least eight subunits) and E. faecalis (eight subunits), with two subunits, Med6 and Med11 being required only against A. fumigatus. Med31 but not Med17 is required in fighting off injected M. robertsii conidia. Thus, the involvement of Mediator in Drosophila innate immunity is more complex than expected.
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Affiliation(s)
- Chuqin Huang
- Sino-French Hoffman Institute, Guangzhou Medical University, Guangzhou, China
| | - Rui Xu
- Sino-French Hoffman Institute, Guangzhou Medical University, Guangzhou, China
- Université de Strasbourg, UPR 9022 du CNRS, Strasbourg, France
| | - Samuel Liégeois
- Sino-French Hoffman Institute, Guangzhou Medical University, Guangzhou, China
- Université de Strasbourg, UPR 9022 du CNRS, Strasbourg, France
| | - Di Chen
- Sino-French Hoffman Institute, Guangzhou Medical University, Guangzhou, China
| | - Zi Li
- Sino-French Hoffman Institute, Guangzhou Medical University, Guangzhou, China
| | - Dominique Ferrandon
- Sino-French Hoffman Institute, Guangzhou Medical University, Guangzhou, China
- Université de Strasbourg, UPR 9022 du CNRS, Strasbourg, France
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50
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Zhao H, Young N, Kalchschmidt J, Lieberman J, El Khattabi L, Casellas R, Asturias FJ. Structure of mammalian Mediator complex reveals Tail module architecture and interaction with a conserved core. Nat Commun 2021; 12:1355. [PMID: 33649303 PMCID: PMC7921410 DOI: 10.1038/s41467-021-21601-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Accepted: 02/01/2021] [Indexed: 01/04/2023] Open
Abstract
The Mediator complex plays an essential and multi-faceted role in regulation of RNA polymerase II transcription in all eukaryotes. Structural analysis of yeast Mediator has provided an understanding of the conserved core of the complex and its interaction with RNA polymerase II but failed to reveal the structure of the Tail module that contains most subunits targeted by activators and repressors. Here we present a molecular model of mammalian (Mus musculus) Mediator, derived from a 4.0 Å resolution cryo-EM map of the complex. The mammalian Mediator structure reveals that the previously unresolved Tail module, which includes a number of metazoan specific subunits, interacts extensively with core Mediator and has the potential to influence its conformation and interactions.
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Affiliation(s)
- Haiyan Zhao
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical School, Aurora, CO, USA
| | - Natalie Young
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical School, Aurora, CO, USA
| | | | | | - Laila El Khattabi
- Institut Cochin Laboratoire de Cytogénétique Constitutionnelle Pré et Post Natale, Paris, France
| | - Rafael Casellas
- Lymphocyte Nuclear Biology, NIAMS, NIH, Bethesda, MD, USA.,Center for Cancer Research, NCI, NIH, Bethesda, MD, USA
| | - Francisco J Asturias
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical School, Aurora, CO, USA.
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