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Saleh MM, Hundley HA, Zentner GE. Involvement of the SAGA and TFIID coactivator complexes in transcriptional dysregulation caused by the separation of core and tail Mediator modules. G3 (BETHESDA, MD.) 2022; 12:jkac290. [PMID: 36331351 PMCID: PMC9713439 DOI: 10.1093/g3journal/jkac290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 09/28/2022] [Indexed: 02/17/2024]
Abstract
Regulation of RNA polymerase II transcription requires the concerted efforts of several multisubunit coactivator complexes, which interact with the RNA polymerase II preinitiation complex to stimulate transcription. We previously showed that separation of the Mediator core from Mediator's tail module results in modest overactivation of genes annotated as highly dependent on TFIID for expression. However, it is unclear if other coactivators are involved in this phenomenon. Here, we show that the overactivation of certain genes by Mediator core/tail separation is blunted by disruption of the Spt-Ada-Gcn5-Acetyl transferase complex through the removal of its structural Spt20 subunit, though this downregulation does not appear to completely depend on reduced Spt-Ada-Gcn5-Acetyl transferase association with the genome. Consistent with the enrichment of TFIID-dependent genes among genes overactivated by Mediator core/tail separation, depletion of the essential TFIID subunit Taf13 suppressed the overactivation of these genes when Med16 was simultaneously removed. As with Spt-Ada-Gcn5-Acetyl transferase, this effect did not appear to be fully dependent on the reduced genomic association of TFIID. Given that the observed changes in gene expression could not be clearly linked to alterations in Spt-Ada-Gcn5-Acetyl transferase or TFIID occupancy, our data may suggest that the Mediator core/tail connection is important for the modulation of Spt-Ada-Gcn5-Acetyl transferase and/or TFIID conformation and/or function at target genes.
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Affiliation(s)
- Moustafa M Saleh
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Heather A Hundley
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Gabriel E Zentner
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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2
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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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3
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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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4
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Whole-genome methods to define DNA and histone accessibility and long-range interactions in chromatin. Biochem Soc Trans 2022; 50:199-212. [PMID: 35166326 PMCID: PMC9847230 DOI: 10.1042/bst20210959] [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: 11/02/2021] [Revised: 12/30/2021] [Accepted: 01/24/2022] [Indexed: 02/08/2023]
Abstract
Defining the genome-wide chromatin landscape has been a goal of experimentalists for decades. Here we review highlights of these efforts, from seminal experiments showing discontinuities in chromatin structure related to gene activation to extensions of these methods elucidating general features of chromatin related to gene states by exploiting deep sequencing methods. We also review chromatin conformational capture methods to identify patterns in long-range interactions between genomic loci.
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Fischer V, Plassard D, Ye T, Reina-San-Martin B, Stierle M, Tora L, Devys D. The related coactivator complexes SAGA and ATAC control embryonic stem cell self-renewal through acetyltransferase-independent mechanisms. Cell Rep 2021; 36:109598. [PMID: 34433046 PMCID: PMC8430043 DOI: 10.1016/j.celrep.2021.109598] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 06/17/2021] [Accepted: 08/03/2021] [Indexed: 01/10/2023] Open
Abstract
SAGA (Spt-Ada-Gcn5 acetyltransferase) and ATAC (Ada-two-A-containing) are two related coactivator complexes, sharing the same histone acetyltransferase (HAT) subunit. The HAT activities of SAGA and ATAC are required for metazoan development, but the role of these complexes in RNA polymerase II transcription is less understood. To determine whether SAGA and ATAC have redundant or specific functions, we compare the effects of HAT inactivation in each complex with that of inactivation of either SAGA or ATAC core subunits in mouse embryonic stem cells (ESCs). We show that core subunits of SAGA or ATAC are required for complex assembly and mouse ESC growth and self-renewal. Surprisingly, depletion of HAT module subunits causes a global decrease in histone H3K9 acetylation, but does not result in significant phenotypic or transcriptional defects. Thus, our results indicate that SAGA and ATAC are differentially required for self-renewal of mouse ESCs by regulating transcription through different pathways in a HAT-independent manner.
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Affiliation(s)
- Veronique Fischer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch Cedex, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch Cedex, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch Cedex, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Damien Plassard
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch Cedex, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch Cedex, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch Cedex, France; Université de Strasbourg, 67000 Strasbourg, France; Plateforme GenomEast, infrastructure France Génomique, Illkirch, France
| | - Tao Ye
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch Cedex, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch Cedex, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch Cedex, France; Université de Strasbourg, 67000 Strasbourg, France; Plateforme GenomEast, infrastructure France Génomique, Illkirch, France
| | - Bernardo Reina-San-Martin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch Cedex, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch Cedex, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch Cedex, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Matthieu Stierle
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch Cedex, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch Cedex, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch Cedex, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Laszlo Tora
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch Cedex, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch Cedex, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch Cedex, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Didier Devys
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch Cedex, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch Cedex, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch Cedex, France; Université de Strasbourg, 67000 Strasbourg, France.
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Connection of core and tail Mediator modules restrains transcription from TFIID-dependent promoters. PLoS Genet 2021; 17:e1009529. [PMID: 34383744 PMCID: PMC8384189 DOI: 10.1371/journal.pgen.1009529] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 08/24/2021] [Accepted: 07/30/2021] [Indexed: 11/19/2022] Open
Abstract
The Mediator coactivator complex is divided into four modules: head, middle, tail, and kinase. Deletion of the architectural subunit Med16 separates core Mediator (cMed), comprising the head, middle, and scaffold (Med14), from the tail. However, the direct global effects of tail/cMed disconnection are unclear. We find that rapid depletion of Med16 downregulates genes that require the SAGA complex for full expression, consistent with their reported tail dependence, but also moderately overactivates TFIID-dependent genes in a manner partly dependent on the separated tail, which remains associated with upstream activating sequences. Suppression of TBP dynamics via removal of the Mot1 ATPase partially restores normal transcriptional activity to Med16-depleted cells, suggesting that cMed/tail separation results in an imbalance in the levels of PIC formation at SAGA-requiring and TFIID-dependent genes. We propose that the preferential regulation of SAGA-requiring genes by tailed Mediator helps maintain a proper balance of transcription between these genes and those more dependent on TFIID. Composed of over two dozen subunits, the Mediator complex plays several roles in RNA polymerase II (RNAPII) transcription in eukaryotes. In yeast, deletion of Med16, which splits Mediator into two stable subcomplexes, both increases and decreases transcript levels, suggesting that Med16 might play a repressive role. However, the direct effects of Med16 removal on RNAPII transcription have not been assessed, owing to the use of deletion mutants and measurement of steady-state RNA levels in prior studies. Here, using a combination of inducible protein depletion and analysis of nascent RNA, we find that Med16 removal 1) downregulates a small group of genes reported to be highly dependent on the SAGA complex and 2) upregulates a larger set of genes reported to be more dependent on the TFIID complex in a manner dependent on another component of Mediator. We find that artificially altering the balance of transcription pre-initiation complex (PIC) formation toward SAGA-requiring promoters and away from TFIID-dependent promoters partially restores normal transcription, indicating a contribution of altered PIC formation to the transcriptional alterations observed with Med16 loss. Taken together, our results indicate that the structural integrity of Mediator is important for maintaining balanced transcription between different gene classes.
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Tourigny JP, Schumacher K, Saleh MM, Devys D, Zentner GE. Architectural Mediator subunits are differentially essential for global transcription in Saccharomyces cerevisiae. Genetics 2021; 217:iyaa042. [PMID: 33789343 PMCID: PMC8045717 DOI: 10.1093/genetics/iyaa042] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 12/16/2020] [Indexed: 12/18/2022] Open
Abstract
Mediator is a modular coactivator complex involved in the transcription of the majority of RNA polymerase II-regulated genes. However, the degrees to which individual core subunits of Mediator contribute to its activity have been unclear. Here, we investigate the contribution of two essential architectural subunits of Mediator to transcription in Saccharomyces cerevisiae. We show that acute depletion of the main complex scaffold Med14 or the head module nucleator Med17 is lethal and results in global transcriptional downregulation, though Med17 removal has a markedly greater negative effect. Consistent with this, Med17 depletion impairs preinitiation complex (PIC) assembly to a greater extent than Med14 removal. Co-depletion of Med14 and Med17 reduced transcription and TFIIB promoter occupancy similarly to Med17 ablation alone, indicating that the contributions of Med14 and Med17 to Mediator function are not additive. We propose that, while the structural integrity of complete Mediator and the head module are both important for PIC assembly and transcription, the head module plays a greater role in this process and is thus the key functional module of Mediator in this regard.
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Affiliation(s)
- Jason P Tourigny
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Kenny Schumacher
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France
- UMR7104, Centre National de la Recherche Scientifique, 67404 Illkirch, France
- U964, Institut National de la Santé et de la Recherche Médicale, 67404 Illkirch, France
- Université de Strasbourg, 67404 Illkirch, France
| | - Moustafa M Saleh
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Didier Devys
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France
- UMR7104, Centre National de la Recherche Scientifique, 67404 Illkirch, France
- U964, Institut National de la Santé et de la Recherche Médicale, 67404 Illkirch, France
- Université de Strasbourg, 67404 Illkirch, France
| | - Gabriel E Zentner
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
- Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN 46202, USA
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Abstract
To persist in their dynamic human host environments, fungal pathogens must sense and adapt by modulating their gene expression to fulfill their cellular needs. Understanding transcriptional regulation on a global scale would uncover cellular processes linked to persistence and virulence mechanisms that could be targeted for antifungal therapeutics. Infections associated with the yeast Candida albicans, a highly prevalent fungal pathogen, and the multiresistant related species Candida auris are becoming a serious public health threat. To define the set of a gene regulated by a transcriptional regulator in C. albicans, chromatin immunoprecipitation (ChIP)-based techniques, including ChIP with microarray technology (ChIP-chip) or ChIP-DNA sequencing (ChIP-seq), have been widely used. Here, we describe a new set of PCR-based micrococcal nuclease (MNase)-tagging plasmids for C. albicans and other Candida spp. to determine the genome-wide location of any transcriptional regulator of interest using chromatin endogenous cleavage (ChEC) coupled to high-throughput sequencing (ChEC-seq). The ChEC procedure does not require protein-DNA cross-linking or sonication, thus avoiding artifacts related to epitope masking or the hyper-ChIPable euchromatic phenomenon. In a proof-of-concept application of ChEC-seq, we provided a high-resolution binding map of the SWI/SNF chromatin remodeling complex, a master regulator of fungal fitness in C. albicans, in addition to the transcription factor Nsi1 that is an ortholog of the DNA-binding protein Reb1 for which genome-wide occupancy was previously established in Saccharomyces cerevisiae The ChEC-seq procedure described here will allow a high-resolution genomic location definition which will enable a better understanding of transcriptional regulatory circuits that govern fungal fitness and drug resistance in these medically important fungi.IMPORTANCE Systemic fungal infections caused by Candida albicans and the "superbug" Candida auris are becoming a serious public health threat. The ability of these yeasts to cause disease is linked to their faculty to modulate the expression of genes that mediate their escape from the immune surveillance and their persistence in the different unfavorable niches within the host. Comprehensive knowledge on gene expression control of fungal fitness is consequently an interesting framework for the identification of essential infection processes that could be hindered by chemicals as potential therapeutics. Here, we expanded the use of ChEC-seq, a technique that was initially developed in the yeast model Saccharomyces cerevisiae to identify genes that are modulated by a transcriptional regulator, in pathogenic yeasts from the genus Candida This robust technique will allow a better characterization of key gene expression regulators and their contribution to virulence and antifungal resistance in these pathogenic yeasts.
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