1
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Dhillon N, Kamakaka RT. Transcriptional silencing in Saccharomyces cerevisiae: known unknowns. Epigenetics Chromatin 2024; 17:28. [PMID: 39272151 PMCID: PMC11401328 DOI: 10.1186/s13072-024-00553-7] [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: 07/02/2024] [Accepted: 09/02/2024] [Indexed: 09/15/2024] Open
Abstract
Transcriptional silencing in Saccharomyces cerevisiae is a persistent and highly stable form of gene repression. It involves DNA silencers and repressor proteins that bind nucleosomes. The silenced state is influenced by numerous factors including the concentration of repressors, nature of activators, architecture of regulatory elements, modifying enzymes and the dynamics of chromatin.Silencers function to increase the residence time of repressor Sir proteins at silenced domains while clustering of silenced domains enables increased concentrations of repressors and helps facilitate long-range interactions. The presence of an accessible NDR at the regulatory regions of silenced genes, the cycling of chromatin configurations at regulatory sites, the mobility of Sir proteins, and the non-uniform distribution of the Sir proteins across the silenced domain, all result in silenced chromatin that only stably silences weak promoters and enhancers via changes in transcription burst duration and frequency.These data collectively suggest that silencing is probabilistic and the robustness of silencing is achieved through sub-optimization of many different nodes of action such that a stable expression state is generated and maintained even though individual constituents are in constant flux.
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Affiliation(s)
- Namrita Dhillon
- Department of Biomolecular Engineering, University of California, 1156 High Street, Santa Cruz, CA, 95064, USA
| | - Rohinton T Kamakaka
- Department of MCD Biology, University of California, 1156 High Street, Santa Cruz, CA, 95064, USA.
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2
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Flury V, Groth A. Safeguarding the epigenome through the cell cycle: a multitasking game. Curr Opin Genet Dev 2024; 85:102161. [PMID: 38447236 DOI: 10.1016/j.gde.2024.102161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 01/29/2024] [Indexed: 03/08/2024]
Abstract
Sustaining cell identity and function across cell division is germane to human development, healthspan, and cancer avoidance. This relies significantly on propagation of chromatin organization between cell generations, as chromatin presents a barrier to cell fate and cell state conversions. Inheritance of chromatin states across the many cell divisions required for development and tissue homeostasis represents a major challenge, especially because chromatin is disrupted to allow passage of the DNA replication fork to synthesize the two daughter strands. This process also leads to a twofold dilution of epigenetic information in histones, which needs to be accurately restored for faithful propagation of chromatin states across cell divisions. Recent research has identified distinct multilayered mechanisms acting to propagate epigenetic information to daughter strands. Here, we summarize key principles of how epigenetic information in parental histones is transferred across DNA replication and how new histones robustly acquire the same information postreplication, representing a core component of epigenetic cell memory.
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Affiliation(s)
- Valentin Flury
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Centre, University of Copenhagen, 2200 Copenhagen, Denmark. https://twitter.com/@ValeFlury
| | - Anja Groth
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Centre, University of Copenhagen, 2200 Copenhagen, Denmark; Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen, Denmark.
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3
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Meeussen JVW, Lenstra TL. Time will tell: comparing timescales to gain insight into transcriptional bursting. Trends Genet 2024; 40:160-174. [PMID: 38216391 PMCID: PMC10860890 DOI: 10.1016/j.tig.2023.11.003] [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: 09/13/2023] [Revised: 11/27/2023] [Accepted: 11/27/2023] [Indexed: 01/14/2024]
Abstract
Recent imaging studies have captured the dynamics of regulatory events of transcription inside living cells. These events include transcription factor (TF) DNA binding, chromatin remodeling and modification, enhancer-promoter (E-P) proximity, cluster formation, and preinitiation complex (PIC) assembly. Together, these molecular events culminate in stochastic bursts of RNA synthesis, but their kinetic relationship remains largely unclear. In this review, we compare the timescales of upstream regulatory steps (input) with the kinetics of transcriptional bursting (output) to generate mechanistic models of transcription dynamics in single cells. We highlight open questions and potential technical advances to guide future endeavors toward a quantitative and kinetic understanding of transcription regulation.
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Affiliation(s)
- Joseph V W Meeussen
- Division of Gene Regulation, The Netherlands Cancer Institute, Oncode Institute, Amsterdam 1066CX, The Netherlands
| | - Tineke L Lenstra
- Division of Gene Regulation, The Netherlands Cancer Institute, Oncode Institute, Amsterdam 1066CX, The Netherlands.
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4
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Pratx L, Wendering P, Kappel C, Nikoloski Z, Bäurle I. Histone retention preserves epigenetic marks during heat stress-induced transcriptional memory in plants. EMBO J 2023; 42:e113595. [PMID: 37937667 PMCID: PMC10711655 DOI: 10.15252/embj.2023113595] [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: 01/24/2023] [Revised: 10/19/2023] [Accepted: 10/19/2023] [Indexed: 11/09/2023] Open
Abstract
Plants often experience recurrent stressful events, for example, during heat waves. They can be primed by heat stress (HS) to improve the survival of more severe heat stress conditions. At certain genes, sustained expression is induced for several days beyond the initial heat stress. This transcriptional memory is associated with hyper-methylation of histone H3 lysine 4 (H3K4me3), but it is unclear how this is maintained for extended periods. Here, we determined histone turnover by measuring the chromatin association of HS-induced histone H3.3. Genome-wide histone turnover was not homogenous; in particular, H3.3 was retained longer at heat stress memory genes compared to HS-induced non-memory genes during the memory phase. While low nucleosome turnover retained H3K4 methylation, methylation loss did not affect turnover, suggesting that low nucleosome turnover sustains H3K4 methylation, but not vice versa. Together, our results unveil the modulation of histone turnover as a mechanism to retain environmentally mediated epigenetic modifications.
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Affiliation(s)
- Loris Pratx
- Plant Epigenetics, Institute for Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
| | - Philipp Wendering
- Bioinformatics, Institute for Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
- Systems Biology and Mathematical Modeling GroupMax Planck Institute of Molecular Plant PhysiologyPotsdamGermany
| | - Christian Kappel
- Genetics, Institute for Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
| | - Zoran Nikoloski
- Bioinformatics, Institute for Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
- Systems Biology and Mathematical Modeling GroupMax Planck Institute of Molecular Plant PhysiologyPotsdamGermany
| | - Isabel Bäurle
- Plant Epigenetics, Institute for Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
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5
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Robert F, Jeronimo C. Transcription-coupled nucleosome assembly. Trends Biochem Sci 2023; 48:978-992. [PMID: 37657993 DOI: 10.1016/j.tibs.2023.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 07/21/2023] [Accepted: 08/04/2023] [Indexed: 09/03/2023]
Abstract
Eukaryotic transcription occurs on chromatin, where RNA polymerase II encounters nucleosomes during elongation. These nucleosomes must unravel for the DNA to enter the active site. However, in most transcribed genes, nucleosomes remain intact due to transcription-coupled chromatin assembly mechanisms. These mechanisms primarily involve the local reassembly of displaced nucleosomes to prevent (epi)genomic instability and the emergence of cryptic transcription. As a fail-safe mechanism, cells can assemble nucleosomes de novo, particularly in highly transcribed genes, but this may result in the loss of epigenetic information. This review examines transcription-coupled chromatin assembly, with an emphasis on studies in yeast and recent structural studies. These studies shed light on how elongation factors and histone chaperones coordinate to enable nucleosome recycling during transcription.
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Affiliation(s)
- François Robert
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada; Département de Médecine, Faculté de Médecine, Université de Montréal, 2900 Boul. Édouard-Montpetit, Montréal, QC H3T 1J4, Canada; Faculty of Medicine, Division of Experimental Medicine, McGill University, Montréal, QC H3A 1A3, Canada.
| | - Célia Jeronimo
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada
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6
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Lupo O, Kumar DK, Livne R, Chappleboim M, Levy I, Barkai N. The architecture of binding cooperativity between densely bound transcription factors. Cell Syst 2023; 14:732-745.e5. [PMID: 37527656 DOI: 10.1016/j.cels.2023.06.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 05/23/2023] [Accepted: 06/27/2023] [Indexed: 08/03/2023]
Abstract
The binding of transcription factors (TFs) along genomes is restricted to a subset of sites containing their preferred motifs. TF-binding specificity is often attributed to the co-binding of interacting TFs; however, apart from specific examples, this model remains untested. Here, we define dependencies among budding yeast TFs that localize to overlapping promoters by profiling the genome-wide consequences of co-depleting multiple TFs. We describe unidirectional interactions, revealing Msn2 as a central factor allowing TF binding at its target promoters. By contrast, no case of mutual cooperation was observed. Particularly, Msn2 retained binding at its preferred promoters upon co-depletion of fourteen similarly bound TFs. Overall, the consequences of TF co-depletions were moderate, limited to a subset of promoters, and failed to explain the role of regions outside the DNA-binding domain in directing TF-binding preferences. Our results call for re-evaluating the role of cooperative interactions in directing TF-binding preferences.
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Affiliation(s)
- Offir Lupo
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Divya Krishna Kumar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Rotem Livne
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Michal Chappleboim
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Idan Levy
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Naama Barkai
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel.
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7
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Jonas F, Vidavski M, Benuck E, Barkai N, Yaakov G. Nucleosome retention by histone chaperones and remodelers occludes pervasive DNA-protein binding. Nucleic Acids Res 2023; 51:8496-8513. [PMID: 37493599 PMCID: PMC10484674 DOI: 10.1093/nar/gkad615] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 06/07/2023] [Accepted: 07/11/2023] [Indexed: 07/27/2023] Open
Abstract
DNA packaging within chromatin depends on histone chaperones and remodelers that form and position nucleosomes. Cells express multiple such chromatin regulators with overlapping in-vitro activities. Defining specific in-vivo activities requires monitoring histone dynamics during regulator depletion, which has been technically challenging. We have recently generated histone-exchange sensors in Saccharomyces cerevisiae, which we now use to define the contributions of 15 regulators to histone dynamics genome-wide. While replication-independent exchange in unperturbed cells maps to promoters, regulator depletions primarily affected gene bodies. Depletion of Spt6, Spt16 or Chd1 sharply increased nucleosome replacement sequentially at the beginning, middle or end of highly expressed gene bodies. They further triggered re-localization of chaperones to affected gene body regions, which compensated for nucleosome loss during transcription complex passage, but concurred with extensive TF binding in gene bodies. We provide a unified quantitative screen highlighting regulator roles in retaining nucleosome binding during transcription and preserving genomic packaging.
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Affiliation(s)
- Felix Jonas
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Matan Vidavski
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Eli Benuck
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Naama Barkai
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Gilad Yaakov
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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8
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Dunjić M, Jonas F, Yaakov G, More R, Mayshar Y, Rais Y, Orenbuch AH, Cheng S, Barkai N, Stelzer Y. Histone exchange sensors reveal variant specific dynamics in mouse embryonic stem cells. Nat Commun 2023; 14:3791. [PMID: 37365167 DOI: 10.1038/s41467-023-39477-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 06/15/2023] [Indexed: 06/28/2023] Open
Abstract
Eviction of histones from nucleosomes and their exchange with newly synthesized or alternative variants is a central epigenetic determinant. Here, we define the genome-wide occupancy and exchange pattern of canonical and non-canonical histone variants in mouse embryonic stem cells by genetically encoded exchange sensors. While exchange of all measured variants scales with transcription, we describe variant-specific associations with transcription elongation and Polycomb binding. We found considerable exchange of H3.1 and H2B variants in heterochromatin and repeat elements, contrasting the occupancy and little exchange of H3.3 in these regions. This unexpected association between H3.3 occupancy and exchange of canonical variants is also evident in active promoters and enhancers, and further validated by reduced H3.1 dynamics following depletion of H3.3-specific chaperone, HIRA. Finally, analyzing transgenic mice harboring H3.1 or H3.3 sensors demonstrates the vast potential of this system for studying histone exchange and its impact on gene expression regulation in vivo.
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Affiliation(s)
- Marko Dunjić
- Department of Molecular Cell Biology, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Felix Jonas
- Department of Molecular Genetics, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Gilad Yaakov
- Department of Molecular Genetics, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Roye More
- Department of Molecular Cell Biology, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Yoav Mayshar
- Department of Molecular Cell Biology, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Yoach Rais
- Department of Molecular Cell Biology, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | | | - Saifeng Cheng
- Department of Molecular Cell Biology, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Naama Barkai
- Department of Molecular Genetics, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Yonatan Stelzer
- Department of Molecular Cell Biology, Weizmann Institute of Science, 7610001, Rehovot, Israel.
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9
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Narita T, Higashijima Y, Kilic S, Liebner T, Walter J, Choudhary C. Acetylation of histone H2B marks active enhancers and predicts CBP/p300 target genes. Nat Genet 2023; 55:679-692. [PMID: 37024579 PMCID: PMC10101849 DOI: 10.1038/s41588-023-01348-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 02/23/2023] [Indexed: 04/08/2023]
Abstract
Chromatin features are widely used for genome-scale mapping of enhancers. However, discriminating active enhancers from other cis-regulatory elements, predicting enhancer strength and identifying their target genes is challenging. Here we establish histone H2B N-terminus multisite lysine acetylation (H2BNTac) as a signature of active enhancers. H2BNTac prominently marks candidate active enhancers and a subset of promoters and discriminates them from ubiquitously active promoters. Two mechanisms underlie the distinct H2BNTac specificity: (1) unlike H3K27ac, H2BNTac is specifically catalyzed by CBP/p300; (2) H2A-H2B, but not H3-H4, are rapidly exchanged through transcription-induced nucleosome remodeling. H2BNTac-positive candidate enhancers show a high validation rate in orthogonal enhancer activity assays and a vast majority of endogenously active enhancers are marked by H2BNTac and H3K27ac. Notably, H2BNTac intensity predicts enhancer strength and outperforms current state-of-the-art models in predicting CBP/p300 target genes. These findings have broad implications for generating fine-grained enhancer maps and modeling CBP/p300-dependent gene regulation.
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Affiliation(s)
- Takeo Narita
- Department of Proteomics, The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Yoshiki Higashijima
- Department of Proteomics, The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sinan Kilic
- Department of Proteomics, The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tim Liebner
- Department of Proteomics, The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jonas Walter
- Department of Proteomics, The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Chunaram Choudhary
- Department of Proteomics, The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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10
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Flury V, Reverón-Gómez N, Alcaraz N, Stewart-Morgan KR, Wenger A, Klose RJ, Groth A. Recycling of modified H2A-H2B provides short-term memory of chromatin states. Cell 2023; 186:1050-1065.e19. [PMID: 36750094 PMCID: PMC9994263 DOI: 10.1016/j.cell.2023.01.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 11/11/2022] [Accepted: 01/06/2023] [Indexed: 02/08/2023]
Abstract
Chromatin landscapes are disrupted during DNA replication and must be restored faithfully to maintain genome regulation and cell identity. The histone H3-H4 modification landscape is restored by parental histone recycling and modification of new histones. How DNA replication impacts on histone H2A-H2B is currently unknown. Here, we measure H2A-H2B modifications and H2A.Z during DNA replication and across the cell cycle using quantitative genomics. We show that H2AK119ub1, H2BK120ub1, and H2A.Z are recycled accurately during DNA replication. Modified H2A-H2B are segregated symmetrically to daughter strands via POLA1 on the lagging strand, but independent of H3-H4 recycling. Post-replication, H2A-H2B modification and variant landscapes are quickly restored, and H2AK119ub1 guides accurate restoration of H3K27me3. This work reveals epigenetic transmission of parental H2A-H2B during DNA replication and identifies cross talk between H3-H4 and H2A-H2B modifications in epigenome propagation. We propose that rapid short-term memory of recycled H2A-H2B modifications facilitates restoration of stable H3-H4 chromatin states.
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Affiliation(s)
- Valentin Flury
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Centre, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Nazaret Reverón-Gómez
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Centre, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Nicolas Alcaraz
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Centre, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Kathleen R Stewart-Morgan
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Centre, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Alice Wenger
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Centre, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Robert J Klose
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Anja Groth
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, 2200 Copenhagen, Denmark; Biotech Research and Innovation Centre, University of Copenhagen, 2200 Copenhagen, Denmark.
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11
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Chen JJ, Stermer D, Tanny JC. Decoding histone ubiquitylation. Front Cell Dev Biol 2022; 10:968398. [PMID: 36105353 PMCID: PMC9464978 DOI: 10.3389/fcell.2022.968398] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 08/09/2022] [Indexed: 11/13/2022] Open
Abstract
Histone ubiquitylation is a critical part of both active and repressed transcriptional states, and lies at the heart of DNA damage repair signaling. The histone residues targeted for ubiquitylation are often highly conserved through evolution, and extensive functional studies of the enzymes that catalyze the ubiquitylation and de-ubiquitylation of histones have revealed key roles linked to cell growth and division, development, and disease in model systems ranging from yeast to human cells. Nonetheless, the downstream consequences of these modifications have only recently begun to be appreciated on a molecular level. Here we review the structure and function of proteins that act as effectors or “readers” of histone ubiquitylation. We highlight lessons learned about how ubiquitin recognition lends specificity and function to intermolecular interactions in the context of transcription and DNA repair, as well as what this might mean for how we think about histone modifications more broadly.
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12
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Molenaar TM, van Leeuwen F. SETD2: from chromatin modifier to multipronged regulator of the genome and beyond. Cell Mol Life Sci 2022; 79:346. [PMID: 35661267 PMCID: PMC9167812 DOI: 10.1007/s00018-022-04352-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/09/2022] [Accepted: 05/05/2022] [Indexed: 12/13/2022]
Abstract
Histone modifying enzymes play critical roles in many key cellular processes and are appealing proteins for targeting by small molecules in disease. However, while the functions of histone modifying enzymes are often linked to epigenetic regulation of the genome, an emerging theme is that these enzymes often also act by non-catalytic and/or non-epigenetic mechanisms. SETD2 (Set2 in yeast) is best known for associating with the transcription machinery and methylating histone H3 on lysine 36 (H3K36) during transcription. This well-characterized molecular function of SETD2 plays a role in fine-tuning transcription, maintaining chromatin integrity, and mRNA processing. Here we give an overview of the various molecular functions and mechanisms of regulation of H3K36 methylation by Set2/SETD2. These fundamental insights are important to understand SETD2’s role in disease, most notably in cancer in which SETD2 is frequently inactivated. SETD2 also methylates non-histone substrates such as α-tubulin which may promote genome stability and contribute to the tumor-suppressor function of SETD2. Thus, to understand its role in disease, it is important to understand and dissect the multiple roles of SETD2 within the cell. In this review we discuss how histone methylation by Set2/SETD2 has led the way in connecting histone modifications in active regions of the genome to chromatin functions and how SETD2 is leading the way to showing that we also have to look beyond histones to truly understand the physiological role of an ‘epigenetic’ writer enzyme in normal cells and in disease.
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13
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Evrin C, Serra‐Cardona A, Duan S, Mukherjee PP, Zhang Z, Labib KPM. Spt5 histone binding activity preserves chromatin during transcription by RNA polymerase II. EMBO J 2022; 41:e109783. [PMID: 35102600 PMCID: PMC8886531 DOI: 10.15252/embj.2021109783] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 12/22/2021] [Accepted: 01/06/2022] [Indexed: 12/30/2022] Open
Abstract
Nucleosomes are disrupted transiently during eukaryotic transcription, yet the displaced histones must be retained and redeposited onto DNA, to preserve nucleosome density and associated histone modifications. Here, we show that the essential Spt5 processivity factor of RNA polymerase II (Pol II) plays a direct role in this process in budding yeast. Functional orthologues of eukaryotic Spt5 are present in archaea and bacteria, reflecting its universal role in RNA polymerase processivity. However, eukaryotic Spt5 is unique in having an acidic amino terminal tail (Spt5N) that is sandwiched between the downstream nucleosome and the upstream DNA that emerges from Pol II. We show that Spt5N contains a histone-binding motif that is required for viability in yeast cells and prevents loss of nucleosomal histones within actively transcribed regions. These findings indicate that eukaryotic Spt5 combines two essential activities, which together couple processive transcription to the efficient capture and re-deposition of nucleosomal histones.
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Affiliation(s)
- Cecile Evrin
- The MRC Protein Phosphorylation and Ubiquitylation UnitSchool of Life SciencesUniversity of DundeeDundeeUK
| | - Albert Serra‐Cardona
- Institute for Cancer GeneticsDepartment of Pediatrics and Department of Genetics and DevelopmentColumbia University Irving Medical CenterNew YorkNYUSA
| | - Shoufu Duan
- Institute for Cancer GeneticsDepartment of Pediatrics and Department of Genetics and DevelopmentColumbia University Irving Medical CenterNew YorkNYUSA
| | - Progya P Mukherjee
- The MRC Protein Phosphorylation and Ubiquitylation UnitSchool of Life SciencesUniversity of DundeeDundeeUK
| | - Zhiguo Zhang
- Institute for Cancer GeneticsDepartment of Pediatrics and Department of Genetics and DevelopmentColumbia University Irving Medical CenterNew YorkNYUSA
| | - Karim P M Labib
- The MRC Protein Phosphorylation and Ubiquitylation UnitSchool of Life SciencesUniversity of DundeeDundeeUK
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