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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Movilla Miangolarra A, Saxton DS, Yan Z, Rine J, Howard M. Two-way feedback between chromatin compaction and histone modification state explains Saccharomyces cerevisiae heterochromatin bistability. Proc Natl Acad Sci U S A 2024; 121:e2403316121. [PMID: 38593082 PMCID: PMC11032488 DOI: 10.1073/pnas.2403316121] [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: 02/21/2024] [Accepted: 03/02/2024] [Indexed: 04/11/2024] Open
Abstract
Compact chromatin is closely linked with gene silencing in part by sterically masking access to promoters, inhibiting transcription factor binding and preventing polymerase from efficiently transcribing a gene. However, a broader hypothesis suggests that chromatin compaction can be both a cause and a consequence of the locus histone modification state, with a tight bidirectional interaction underpinning bistable transcriptional states. To rigorously test this hypothesis, we developed a mathematical model for the dynamics of the HMR locus in Saccharomyces cerevisiae, that incorporates activating histone modifications, silencing proteins, and a dynamic, acetylation-dependent, three-dimensional locus size. Chromatin compaction enhances silencer protein binding, which in turn feeds back to remove activating histone modifications, leading to further compaction. The bistable output of the model was in good agreement with prior quantitative data, including switching rates from expressed to silent states (and vice versa), and protein binding/histone modification levels within the locus. We then tested the model by predicting changes in switching rates as the genetic length of the locus was increased, which were then experimentally verified. Such bidirectional feedback between chromatin compaction and the histone modification state may be a widespread and important regulatory mechanism given the hallmarks of many heterochromatic regions: physical chromatin compaction and dimerizing (or multivalent) silencing proteins.
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Affiliation(s)
| | - Daniel S. Saxton
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
| | - Zhi Yan
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
| | - Jasper Rine
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
| | - Martin Howard
- Department of Computational and Systems Biology, John Innes Centre, NorwichNR4 7UH, United Kingdom
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3
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Yuan AH, Moazed D. Minimal requirements for the epigenetic inheritance of engineered silent chromatin domains. Proc Natl Acad Sci U S A 2024; 121:e2318455121. [PMID: 38198529 PMCID: PMC10801849 DOI: 10.1073/pnas.2318455121] [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: 10/22/2023] [Accepted: 12/06/2023] [Indexed: 01/12/2024] Open
Abstract
Mechanisms enabling genetically identical cells to differentially regulate gene expression are complex and central to organismal development and evolution. While gene silencing pathways involving DNA sequence-specific recruitment of histone-modifying enzymes are prevalent in nature, examples of sequence-independent heritable gene silencing are scarce. Studies of the fission yeast Schizosaccharomyces pombe indicate that sequence-independent propagation of heterochromatin can occur but requires numerous multisubunit protein complexes and their diverse activities. Such complexity has so far precluded a coherent articulation of the minimal requirements for heritable gene silencing by conventional in vitro reconstitution approaches. Here, we take an unconventional approach to defining these requirements by engineering sequence-independent silent chromatin inheritance in budding yeast Saccharomyces cerevisiae cells. The mechanism conferring memory upon these cells is remarkably simple and requires only two proteins, one that recognizes histone H3 lysine 9 methylation (H3K9me) and catalyzes the deacetylation of histone H4 lysine 16 (H4K16), and another that recognizes deacetylated H4K16 and catalyzes H3K9me. Together, these bilingual "read-write" proteins form an interdependent positive feedback loop that is sufficient for the transmission of DNA sequence-independent silent information over multiple generations.
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Affiliation(s)
- Andy H. Yuan
- HHMI, Harvard Medical School, Boston, MA02115
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA02115
| | - Danesh Moazed
- HHMI, Harvard Medical School, Boston, MA02115
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA02115
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4
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Hamali B, Amine AAA, Al-Sady B. Regulation of the heterochromatin spreading reaction by trans-acting factors. Open Biol 2023; 13:230271. [PMID: 37935357 PMCID: PMC10645111 DOI: 10.1098/rsob.230271] [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: 08/10/2023] [Accepted: 10/03/2023] [Indexed: 11/09/2023] Open
Abstract
Heterochromatin is a gene-repressive protein-nucleic acid ultrastructure that is initially nucleated by DNA sequences. However, following nucleation, heterochromatin can then propagate along the chromatin template in a sequence-independent manner in a reaction termed spreading. At the heart of this process are enzymes that deposit chemical information on chromatin, which attracts the factors that execute chromatin compaction and transcriptional or co/post-transcriptional gene silencing. Given that these enzymes deposit guiding chemical information on chromatin they are commonly termed 'writers'. While the processes of nucleation and central actions of writers have been extensively studied and reviewed, less is understood about how the spreading process is regulated. We discuss how the chromatin substrate is prepared for heterochromatic spreading, and how trans-acting factors beyond writer enzymes regulate it. We examine mechanisms by which trans-acting factors in Suv39, PRC2, SETDB1 and SIR writer systems regulate spreading of the respective heterochromatic marks across chromatin. While these systems are in some cases evolutionarily and mechanistically quite distant, common mechanisms emerge which these trans-acting factors exploit to tune the spreading reaction.
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Affiliation(s)
- Bulut Hamali
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143, USA
- The G. W. Hooper Foundation, San Francisco, CA 94143, USA
- College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Ahmed A A Amine
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143, USA
- The G. W. Hooper Foundation, San Francisco, CA 94143, USA
| | - Bassem Al-Sady
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143, USA
- The G. W. Hooper Foundation, San Francisco, CA 94143, USA
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5
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Miangolarra AM, Saxton DS, Yan Z, Rine J, Howard M. Two-way feedback between chromatin compaction and histone modification state explains S. cerevisiae heterochromatin bistability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.12.552948. [PMID: 37645983 PMCID: PMC10461966 DOI: 10.1101/2023.08.12.552948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Compact chromatin is closely linked with gene silencing in part by sterically masking access to promoters, inhibiting transcription factor binding and preventing polymerase from efficiently transcribing a gene. Here, we propose a broader view: chromatin compaction can be both a cause and a consequence of the histone modification state, and this tight bidirectional interaction can underpin bistable transcriptional states. To test this theory, we developed a mathematical model for the dynamics of the HMR locus in S. cerevisiae, that incorporates activating histone modifications, silencing proteins and a dynamic, acetylation-dependent, three-dimensional locus size. Chromatin compaction enhances silencer protein binding, which in turn feeds back to remove activating histone modifications, leading to further compaction. The bistable output of the model was in good agreement with prior quantitative data, including switching rates from expressed to silent states, and vice versa, and protein binding levels within the locus. We then tested the model by predicting changes in switching rates as the genetic length of the locus was increased, which were then experimentally verified. This bidirectional feedback between chromatin compaction and the histone modification state may be an important regulatory mechanism at many loci.
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Affiliation(s)
- Ander Movilla Miangolarra
- Dept. of Computational and Systems Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Daniel S Saxton
- Dept. of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Zhi Yan
- Dept. of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Jasper Rine
- Dept. of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Martin Howard
- Dept. of Computational and Systems Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
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6
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Sheu YJ, Kawaguchi RK, Gillis J, Stillman B. Prevalent and dynamic binding of the cell cycle checkpoint kinase Rad53 to gene promoters. eLife 2022; 11:e84320. [PMID: 36520028 PMCID: PMC9797190 DOI: 10.7554/elife.84320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022] Open
Abstract
Replication of the genome must be coordinated with gene transcription and cellular metabolism, especially following replication stress in the presence of limiting deoxyribonucleotides. The Saccharomyces cerevisiae Rad53 (CHEK2 in mammals) checkpoint kinase plays a major role in cellular responses to DNA replication stress. Cell cycle regulated, genome-wide binding of Rad53 to chromatin was examined. Under replication stress, the kinase bound to sites of active DNA replication initiation and fork progression, but unexpectedly to the promoters of about 20% of genes encoding proteins involved in multiple cellular functions. Rad53 promoter binding correlated with changes in expression of a subset of genes. Rad53 promoter binding to certain genes was influenced by sequence-specific transcription factors and less by checkpoint signaling. However, in checkpoint mutants, untimely activation of late-replicating origins reduces the transcription of nearby genes, with concomitant localization of Rad53 to their gene bodies. We suggest that the Rad53 checkpoint kinase coordinates genome-wide replication and transcription under replication stress conditions.
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Affiliation(s)
- Yi-Jun Sheu
- Cold Spring Harbor LaboratoryCold Spring HarborUnited States
| | | | - Jesse Gillis
- Cold Spring Harbor LaboratoryCold Spring HarborUnited States
| | - Bruce Stillman
- Cold Spring Harbor LaboratoryCold Spring HarborUnited States
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7
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Saxton DS, Rine J. Distinct silencer states generate epigenetic states of heterochromatin. Mol Cell 2022; 82:3566-3579.e5. [PMID: 36041432 DOI: 10.1016/j.molcel.2022.08.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 06/23/2022] [Accepted: 07/30/2022] [Indexed: 11/26/2022]
Abstract
Heterochromatic loci can exhibit different transcriptional states in genetically identical cells. A popular model posits that the inheritance of modified histones is sufficient for inheritance of the silenced state. However, silencing inheritance requires silencers and therefore cannot be driven by the inheritance of modified histones alone. To address these observations, we determined the chromatin architectures produced by strong and weak silencers in Saccharomyces. Strong silencers recruited Sir proteins and silenced the locus in all cells. Strikingly, weakening these silencers reduced Sir protein recruitment and stably silenced the locus in some cells; however, this silenced state could probabilistically convert to an expressed state that lacked Sir protein recruitment. Additionally, changes in the constellation of silencer-bound proteins or the concentration of a structural Sir protein modulated the probability that a locus exhibited the silenced or expressed state. These findings argued that distinct silencer states generate epigenetic states and regulate their dynamics.
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Affiliation(s)
- Daniel S Saxton
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Jasper Rine
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
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8
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Ngubo M, Reid JL, Patterton H. Distinct structural groups of histone H3 and H4 residues have divergent effects on chronological lifespan in Saccharomyces cerevisiae. PLoS One 2022; 17:e0268760. [PMID: 35622816 PMCID: PMC9140238 DOI: 10.1371/journal.pone.0268760] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 05/06/2022] [Indexed: 11/19/2022] Open
Abstract
We have performed a comprehensive analysis of the involvement of histone H3 and H4 residues in the regulation of chronological lifespan in yeast and identify four structural groups in the nucleosome that influence lifespan. We also identify residues where substitution with an epigenetic mimic extends lifespan, providing evidence that a simple epigenetic switch, without possible additional background modifications, causes longevity. Residues where substitution result in the most pronounced lifespan extension are all on the exposed face of the nucleosome, with the exception of H3E50, which is present on the lateral surface, between two DNA gyres. Other residues that have a more modest effect on lifespan extension are concentrated at the extremities of the H3-H4 dimer, suggesting a role in stabilizing the dimer in its nucleosome frame. Residues that reduce lifespan are buried in the histone handshake motif, suggesting that these mutations destabilize the octamer structure. All residues exposed on the nucleosome disk face and that cause lifespan extension are known to interact with Sir3. We find that substitution of H4K16 and H4H18 cause Sir3 to redistribute from telomeres and silent mating loci to secondary positions, often enriched for Rap1, Abf1 or Reb1 binding sites, whereas H3E50 does not. The redistribution of Sir3 in the genome can be reproduced by an equilibrium model based on primary and secondary binding sites with different affinities for Sir3. The redistributed Sir3 cause transcriptional repression at most of the new loci, including of genes where null mutants were previously shown to extend chronological lifespan. The transcriptomic profiles of H4K16 and H4H18 mutant strains are very similar, and compatible with a DNA replication stress response. This is distinct from the transcriptomic profile of H3E50, which matches strong induction of oxidative phosphorylation. We propose that the different groups of residues are involved in binding to heterochromatin proteins, in destabilizing the association of the nucleosome DNA, disrupting binding of the H3-H4 dimer in the nucleosome, or disrupting the structural stability of the octamer, each category impacting on chronological lifespan by a different mechanism.
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Affiliation(s)
- Mzwanele Ngubo
- Centre for Bioinformatics and Computational Biology, Stellenbosch University, Stellenbosch, South Africa
| | - Jessica Laura Reid
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
| | - Hugh–George Patterton
- Centre for Bioinformatics and Computational Biology, Stellenbosch University, Stellenbosch, South Africa
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
- * E-mail:
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9
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Brothers M, Rine J. Distinguishing between recruitment and spread of silent chromatin structures in Saccharomyces cerevisiae. eLife 2022; 11:75653. [PMID: 35073254 PMCID: PMC8830885 DOI: 10.7554/elife.75653] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 01/21/2022] [Indexed: 11/13/2022] Open
Abstract
The formation of heterochromatin at HML, HMR, and telomeres in Saccharomyces cerevisiae involves two main steps: Recruitment of Sir proteins to silencers and their spread throughout the silenced domain. We developed a method to study these two processes at single base-pair resolution. Using a fusion protein between the heterochromatin protein Sir3 and the non-site-specific bacterial adenine methyltransferase M.EcoGII, we mapped sites of Sir3-chromatin interactions genome-wide using long-read Nanopore sequencing to detect adenines methylated by the fusion protein and by ChIP-seq to map the distribution of Sir3-M.EcoGII. A silencing-deficient mutant of Sir3 lacking its Bromo-Adjacent Homology (BAH) domain, sir3-bah∆, was still recruited to HML, HMR, and telomeres. However, in the absence of the BAH domain, it was unable to spread away from those recruitment sites. Overexpression of Sir3 did not lead to further spreading at HML, HMR, and most telomeres. A few exceptional telomeres, like 6R, exhibited a small amount of Sir3 spreading, suggesting that boundaries at telomeres responded variably to Sir3 overexpression. Finally, by using a temperature-sensitive allele of SIR3 fused to M.ECOGII, we tracked the positions first methylated after induction and found that repression of genes at HML and HMR began before Sir3 occupied the entire locus.
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Affiliation(s)
- Molly Brothers
- Department of Molecular and Cell Biology, University of California, Berkeley
| | - Jasper Rine
- Department of Molecular and Cell Biology, University of California, Berkeley
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10
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Bordelet H, Costa R, Brocas C, Dépagne J, Veaute X, Busso D, Batté A, Guérois R, Marcand S, Dubrana K. Sir3 heterochromatin protein promotes non-homologous end joining by direct inhibition of Sae2. EMBO J 2022; 41:e108813. [PMID: 34817085 PMCID: PMC8724767 DOI: 10.15252/embj.2021108813] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 11/02/2021] [Accepted: 11/04/2021] [Indexed: 01/07/2023] Open
Abstract
Heterochromatin is a conserved feature of eukaryotic chromosomes, with central roles in gene expression regulation and maintenance of genome stability. How heterochromatin proteins regulate DNA repair remains poorly described. In the yeast Saccharomyces cerevisiae, the silent information regulator (SIR) complex assembles heterochromatin-like chromatin at sub-telomeric chromosomal regions. SIR-mediated repressive chromatin limits DNA double-strand break (DSB) resection, thus protecting damaged chromosome ends during homologous recombination (HR). As resection initiation represents the crossroads between repair by non-homologous end joining (NHEJ) or HR, we asked whether SIR-mediated heterochromatin regulates NHEJ. We show that SIRs promote NHEJ through two pathways, one depending on repressive chromatin assembly, and the other relying on Sir3 in a manner that is independent of its heterochromatin-promoting function. Via physical interaction with the Sae2 protein, Sir3 impairs Sae2-dependent functions of the MRX (Mre11-Rad50-Xrs2) complex, thereby limiting Mre11-mediated resection, delaying MRX removal from DSB ends, and promoting NHEJ.
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Affiliation(s)
- Hélène Bordelet
- Université de Paris and Université Paris‐Saclay, INSERM, iRCM/IBFJ CEA, UMR Stabilité Génétique Cellules Souches et RadiationsFontenay‐aux‐RosesFrance
- Régulation spatiale des génomes, Institut Pasteur, CNRS UMR3525ParisFrance
| | - Rafaël Costa
- Université de Paris and Université Paris‐Saclay, INSERM, iRCM/IBFJ CEA, UMR Stabilité Génétique Cellules Souches et RadiationsFontenay‐aux‐RosesFrance
| | - Clémentine Brocas
- Université de Paris and Université Paris‐Saclay, INSERM, iRCM/IBFJ CEA, UMR Stabilité Génétique Cellules Souches et RadiationsFontenay‐aux‐RosesFrance
| | - Jordane Dépagne
- CIGEx platform. Université de Paris and Université Paris‐Saclay, INSERM, iRCM/IBFJ CEA, UMR Stabilité Génétique Cellules Souches et RadiationsFontenay‐aux‐RosesFrance
| | - Xavier Veaute
- CIGEx platform. Université de Paris and Université Paris‐Saclay, INSERM, iRCM/IBFJ CEA, UMR Stabilité Génétique Cellules Souches et RadiationsFontenay‐aux‐RosesFrance
| | - Didier Busso
- CIGEx platform. Université de Paris and Université Paris‐Saclay, INSERM, iRCM/IBFJ CEA, UMR Stabilité Génétique Cellules Souches et RadiationsFontenay‐aux‐RosesFrance
| | - Amandine Batté
- Université de Paris and Université Paris‐Saclay, INSERM, iRCM/IBFJ CEA, UMR Stabilité Génétique Cellules Souches et RadiationsFontenay‐aux‐RosesFrance
- Center for Integrative GenomicsBâtiment GénopodeUniversity of LausanneLausanneSwitzerland
| | - Raphaël Guérois
- Institute for Integrative Biology of the Cell (I2BC)CEA, CNRS, Université Paris‐Sud, Université Paris‐SaclayGif‐sur‐YvetteFrance
| | - Stéphane Marcand
- Université de Paris and Université Paris‐Saclay, INSERM, iRCM/IBFJ CEA, UMR Stabilité Génétique Cellules Souches et RadiationsFontenay‐aux‐RosesFrance
| | - Karine Dubrana
- Université de Paris and Université Paris‐Saclay, INSERM, iRCM/IBFJ CEA, UMR Stabilité Génétique Cellules Souches et RadiationsFontenay‐aux‐RosesFrance
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11
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Valencia-Sánchez MI, De Ioannes P, Wang M, Truong DM, Lee R, Armache JP, Boeke JD, Armache KJ. Regulation of the Dot1 histone H3K79 methyltransferase by histone H4K16 acetylation. Science 2021; 371:371/6527/eabc6663. [PMID: 33479126 DOI: 10.1126/science.abc6663] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 10/27/2020] [Indexed: 12/30/2022]
Abstract
Dot1 (disruptor of telomeric silencing-1), the histone H3 lysine 79 (H3K79) methyltransferase, is conserved throughout evolution, and its deregulation is found in human leukemias. Here, we provide evidence that acetylation of histone H4 allosterically stimulates yeast Dot1 in a manner distinct from but coordinating with histone H2B ubiquitination (H2BUb). We further demonstrate that this stimulatory effect is specific to acetylation of lysine 16 (H4K16ac), a modification central to chromatin structure. We provide a mechanism of this histone cross-talk and show that H4K16ac and H2BUb play crucial roles in H3K79 di- and trimethylation in vitro and in vivo. These data reveal mechanisms that control H3K79 methylation and demonstrate how H4K16ac, H3K79me, and H2BUb function together to regulate gene transcription and gene silencing to ensure optimal maintenance and propagation of an epigenetic state.
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Affiliation(s)
- Marco Igor Valencia-Sánchez
- Skirball Institute of Biomolecular Medicine, Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Pablo De Ioannes
- Skirball Institute of Biomolecular Medicine, Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Miao Wang
- Skirball Institute of Biomolecular Medicine, Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - David M Truong
- Institute for Systems Genetics, Department of Biochemistry and Molecular Pharmacology, New York University Langone Health, New York, NY 10016, USA
| | - Rachel Lee
- Skirball Institute of Biomolecular Medicine, Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Jean-Paul Armache
- Department of Biochemistry and Molecular Biology, The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Jef D Boeke
- Institute for Systems Genetics, Department of Biochemistry and Molecular Pharmacology, New York University Langone Health, New York, NY 10016, USA
| | - Karim-Jean Armache
- Skirball Institute of Biomolecular Medicine, Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA.
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12
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Ruault M, Scolari VF, Lazar-Stefanita L, Hocher A, Loïodice I, Koszul R, Taddei A. Sir3 mediates long-range chromosome interactions in budding yeast. Genome Res 2021; 31:411-425. [PMID: 33579753 PMCID: PMC7919453 DOI: 10.1101/gr.267872.120] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 12/30/2020] [Indexed: 11/24/2022]
Abstract
Physical contacts between distant loci contribute to regulate genome function. However, the molecular mechanisms responsible for settling and maintaining such interactions remain poorly understood. Here, we investigate the well-conserved interactions between heterochromatin loci. In budding yeast, the 32 telomeres cluster in 3–5 foci in exponentially growing cells. This clustering is functionally linked to the formation of heterochromatin in subtelomeric regions through the recruitment of the silencing SIR complex composed of Sir2/3/4. Combining microscopy and Hi-C on strains expressing different alleles of SIR3, we show that the binding of Sir3 directly promotes long-range contacts between distant regions, including the rDNA, telomeres, and internal Sir3-bound sites. Furthermore, we unveil a new property of Sir3 in promoting rDNA compaction. Finally, using a synthetic approach, we demonstrate that Sir3 can bond loci belonging to different chromosomes together, when targeted to these loci, independently of its interaction with its known partners (Rap1, Sir4), Sir2 activity, or chromosome context. Altogether, these data suggest that Sir3 acts as a molecular bridge that stabilizes long-range interactions.
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Affiliation(s)
- Myriam Ruault
- Institut Curie, PSL University, Sorbonne Université, CNRS, Nuclear Dynamics, 75005 Paris, France
| | - Vittore F Scolari
- Institut Curie, PSL University, Sorbonne Université, CNRS, Nuclear Dynamics, 75005 Paris, France.,Institut Pasteur, Unité Régulation Spatiale des Génomes, CNRS, UMR 3525, C3BI USR 3756, F-75015 Paris, France
| | - Luciana Lazar-Stefanita
- Institut Pasteur, Unité Régulation Spatiale des Génomes, CNRS, UMR 3525, C3BI USR 3756, F-75015 Paris, France.,Sorbonne Université, collège Doctoral, F-75005 Paris, France
| | - Antoine Hocher
- Institut Curie, PSL University, Sorbonne Université, CNRS, Nuclear Dynamics, 75005 Paris, France
| | - Isabelle Loïodice
- Institut Curie, PSL University, Sorbonne Université, CNRS, Nuclear Dynamics, 75005 Paris, France
| | - Romain Koszul
- Institut Pasteur, Unité Régulation Spatiale des Génomes, CNRS, UMR 3525, C3BI USR 3756, F-75015 Paris, France.,Cogitamus Laboratory, F-75005 Paris, France
| | - Angela Taddei
- Institut Curie, PSL University, Sorbonne Université, CNRS, Nuclear Dynamics, 75005 Paris, France.,Cogitamus Laboratory, F-75005 Paris, France
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13
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Nucleosome Positioning Regulates the Establishment, Stability, and Inheritance of Heterochromatin in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 2020; 117:27493-27501. [PMID: 33077593 DOI: 10.1073/pnas.2004111117] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Heterochromatic domains are complex structures composed of nucleosome arrays that are bound by silencing factors. This composition raises the possibility that certain configurations of nucleosome arrays facilitate heterochromatic silencing. We tested this possibility in Saccharomyces cerevisiae by systematically altering the distance between heterochromatic nucleosome-depleted regions (NDRs), which is predicted to affect local nucleosome positioning by limiting how nucleosomes can be packed between NDRs. Consistent with this prediction, serial deletions that altered the distance between heterochromatic NDRs revealed a striking oscillatory relationship between inter-NDR distance and defects in nucleosome positioning. Furthermore, conditions that caused poor nucleosome positioning also led to defects in both heterochromatin stability and the ability of cells to generate and inherit epigenetic transcriptional states. These findings strongly suggest that nucleosome positioning can contribute to formation and maintenance of functional heterochromatin and point to previously unappreciated roles of NDR positioning within heterochromatic domains.
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14
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Hu Y, Tareen A, Sheu YJ, Ireland WT, Speck C, Li H, Joshua-Tor L, Kinney JB, Stillman B. Evolution of DNA replication origin specification and gene silencing mechanisms. Nat Commun 2020; 11:5175. [PMID: 33056978 PMCID: PMC7560902 DOI: 10.1038/s41467-020-18964-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/22/2020] [Indexed: 02/08/2023] Open
Abstract
DNA replication in eukaryotic cells initiates from replication origins that bind the Origin Recognition Complex (ORC). Origin establishment requires well-defined DNA sequence motifs in Saccharomyces cerevisiae and some other budding yeasts, but most eukaryotes lack sequence-specific origins. A 3.9 Å structure of S. cerevisiae ORC-Cdc6-Cdt1-Mcm2-7 (OCCM) bound to origin DNA revealed that a loop within Orc2 inserts into a DNA minor groove and an α-helix within Orc4 inserts into a DNA major groove. Using a massively parallel origin selection assay coupled with a custom mutual-information-based modeling approach, and a separate analysis of whole-genome replication profiling, here we show that the Orc4 α-helix contributes to the DNA sequence-specificity of origins in S. cerevisiae and Orc4 α-helix mutations change genome-wide origin firing patterns. The DNA sequence specificity of replication origins, mediated by the Orc4 α-helix, has co-evolved with the gain of ORC-Sir4-mediated gene silencing and the loss of RNA interference.
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Affiliation(s)
- Y Hu
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY, 11724, USA
- Program in Molecular and Cell Biology, Stony Brook University, Stony Brook, NY, 11794, USA
| | - A Tareen
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY, 11724, USA
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Y-J Sheu
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY, 11724, USA
| | - W T Ireland
- Department of Physics, California Institute of Technology, Pasadena, CA, 91125, USA
| | - C Speck
- DNA Replication Group, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, W12 0NN, London, UK
| | - H Li
- Structural Biology Program, Van Andel Institute, Grand Rapids, MI, 49503, USA
| | - L Joshua-Tor
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY, 11724, USA
- W. M. Keck Structural Biology Laboratory, Howard Hughes Medical Institute, Cold Spring Harbor, NY, 11724, USA
| | - J B Kinney
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY, 11724, USA
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - B Stillman
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY, 11724, USA.
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15
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Wang SH, Lee SP, Tung SY, Tsai SP, Tsai HC, Shen HH, Hong JY, Su KC, Chen FJ, Liu BH, Wu YY, Hsiao SP, Tsai MS, Liou GG. Stabilization of Sir3 interactions by an epigenetic metabolic small molecule, O-acetyl-ADP-ribose, on yeast SIR-nucleosome silent heterochromatin. Arch Biochem Biophys 2019; 671:167-174. [PMID: 31295433 DOI: 10.1016/j.abb.2019.07.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/04/2019] [Accepted: 07/05/2019] [Indexed: 11/24/2022]
Abstract
In Saccharomyces cerevisiae, Sir proteins mediate heterochromatin epigenetic gene silencing. The assembly of silent heterochromatin requires histone deacetylation by Sir2, conformational change of SIR complexes, and followed by spreading of SIR complexes along the chromatin fiber to form extended silent heterochromatin domains. Sir2 couples histone deacetylation and NAD hydrolysis to generate an epigenetic metabolic small molecule, O-acetyl-ADP-ribose (AAR). Here, we demonstrate that AAR physically associates with Sir3 and that polySir3-AAR formation has a specific and essential role in the assembly of silent SIR-nucleosome pre-heterochromatin filaments. Furthermore, we show that AAR is capable of stabilizing binding of the Sir3 BAH domain to the Sir3 carboxyl-terminal region. Our data suggests that for the assembly of SIR-nucleosome pre-heterochromatin filament, the structural rearrangement of SIR-nucleosome is important and result in creating more stable interactions of Sir3, such as the inter-molecule Sir3-Sir3 interaction, and the Sir3-nucleosome interaction within the filaments. In conclusion, our results reveal the importance of AAR, indicating that it not only affects the conformational rearrangement of SIR complexes but also might function as a critical fine-tuning modulatory component of yeast silent SIR-nucleosome pre-heterochromatin by stabilizing the intermolecular interaction between Sir3 N- and C-terminal regions.
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Affiliation(s)
- Sue-Hong Wang
- Department of Biomedical Sciences, Chung Shan Medical University & Department of Medical Research, Chung Shan Medical University Hospital, Taichung, 402, Taiwan, ROC
| | - Sue-Ping Lee
- Institute of Molecular Biology, Academia Sinica, Taipei, 115, Taiwan, ROC
| | - Shu-Yun Tung
- Institute of Molecular Biology, Academia Sinica, Taipei, 115, Taiwan, ROC
| | - Shu-Ping Tsai
- Institute of Molecular Biology, Academia Sinica, Taipei, 115, Taiwan, ROC
| | - Hsieh-Chin Tsai
- Institute of Molecular and Genomic Medicine, National Health Research Institute, Miaoli, 350, Taiwan, ROC
| | - Hsiao-Hsuian Shen
- Institute of Molecular and Genomic Medicine, National Health Research Institute, Miaoli, 350, Taiwan, ROC
| | - Jia-Yang Hong
- Institute of Molecular and Genomic Medicine, National Health Research Institute, Miaoli, 350, Taiwan, ROC
| | - Kuan-Chung Su
- Institute of Molecular and Genomic Medicine, National Health Research Institute, Miaoli, 350, Taiwan, ROC
| | - Feng-Jung Chen
- Institute of Molecular and Genomic Medicine, National Health Research Institute, Miaoli, 350, Taiwan, ROC
| | - Bang-Hung Liu
- Institute of Molecular and Genomic Medicine, National Health Research Institute, Miaoli, 350, Taiwan, ROC
| | - Yu-Yi Wu
- Institute of Molecular and Genomic Medicine, National Health Research Institute, Miaoli, 350, Taiwan, ROC
| | - Sheng-Pin Hsiao
- Institute of Molecular and Genomic Medicine, National Health Research Institute, Miaoli, 350, Taiwan, ROC
| | - Ming-Shiun Tsai
- Department of Food Science and Biotechnology, Da-Yeh University, Changhua, 515, Taiwan, ROC
| | - Gunn-Guang Liou
- Institute of Molecular Biology, Academia Sinica, Taipei, 115, Taiwan, ROC; Institute of Molecular and Genomic Medicine, National Health Research Institute, Miaoli, 350, Taiwan, ROC; Department of Food Science and Biotechnology, Da-Yeh University, Changhua, 515, Taiwan, ROC; Institute of Biological Chemistry, Academia Sinica, Taipei, 115, Taiwan, ROC; Guang EM Laboratory, New Taipei, 242, Taiwan, ROC.
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16
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Faure G, Jézéquel K, Roisné-Hamelin F, Bitard-Feildel T, Lamiable A, Marcand S, Callebaut I. Discovery and Evolution of New Domains in Yeast Heterochromatin Factor Sir4 and Its Partner Esc1. Genome Biol Evol 2019; 11:572-585. [PMID: 30668669 PMCID: PMC6394760 DOI: 10.1093/gbe/evz010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/20/2019] [Indexed: 12/22/2022] Open
Abstract
Sir4 is a core component of heterochromatin found in yeasts of the Saccharomycetaceae family, whose general hallmark is to harbor a three-loci mating-type system with two silent loci. However, a large part of the Sir4 amino acid sequences has remained unexplored, belonging to the dark proteome. Here, we analyzed the phylogenetic profile of yet undescribed foldable regions present in Sir4 as well as in Esc1, an Sir4-interacting perinuclear anchoring protein. Within Sir4, we identified a new conserved motif (TOC) adjacent to the N-terminal KU-binding motif. We also found that the Esc1-interacting region of Sir4 is a Dbf4-related H-BRCT domain, only present in species possessing the HO endonuclease and in Kluveryomyces lactis. In addition, we found new motifs within Esc1 including a motif (Esc1-F) that is unique to species where Sir4 possesses an H-BRCT domain. Mutagenesis of conserved amino acids of the Sir4 H-BRCT domain, known to play a critical role in the Dbf4 function, shows that the function of this domain is separable from the essential role of Sir4 in transcriptional silencing and the protection from HO-induced cutting in Saccharomyces cerevisiae. In the more distant methylotrophic clade of yeasts, which often harbor a two-loci mating-type system with one silent locus, we also found a yet undescribed H-BRCT domain in a distinct protein, the ISWI2 chromatin-remodeling factor subunit Itc1. This study provides new insights on yeast heterochromatin evolution and emphasizes the interest of using sensitive methods of sequence analysis for identifying hitherto ignored functional regions within the dark proteome.
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Affiliation(s)
- Guilhem Faure
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, Paris, France.,National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD
| | - Kévin Jézéquel
- Institut de Biologie François Jacob, IRCM/SIGRR/LTR, INSERM U1274, Université Paris-Saclay, CEA Paris-Saclay, Paris, France.,National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD
| | - Florian Roisné-Hamelin
- Institut de Biologie François Jacob, IRCM/SIGRR/LTR, INSERM U1274, Université Paris-Saclay, CEA Paris-Saclay, Paris, France.,National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD
| | - Tristan Bitard-Feildel
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, Paris, France
| | - Alexis Lamiable
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, Paris, France
| | - Stéphane Marcand
- Institut de Biologie François Jacob, IRCM/SIGRR/LTR, INSERM U1274, Université Paris-Saclay, CEA Paris-Saclay, Paris, France.,Sorbonne Université, UMR CNRS 7238, IBPS, Laboratoire de Biologie Computationnelle et Quantitative (LCQB), Paris, France
| | - Isabelle Callebaut
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, Paris, France.,Sorbonne Université, UMR CNRS 7238, IBPS, Laboratoire de Biologie Computationnelle et Quantitative (LCQB), Paris, France
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17
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Swygert SG, Senapati S, Bolukbasi MF, Wolfe SA, Lindsay S, Peterson CL. SIR proteins create compact heterochromatin fibers. Proc Natl Acad Sci U S A 2018; 115:12447-12452. [PMID: 30455303 PMCID: PMC6298083 DOI: 10.1073/pnas.1810647115] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Heterochromatin is a silenced chromatin region essential for maintaining genomic stability and driving developmental processes. The complicated structure and dynamics of heterochromatin have rendered it difficult to characterize. In budding yeast, heterochromatin assembly requires the SIR proteins-Sir3, believed to be the primary structural component of SIR heterochromatin, and the Sir2-4 complex, responsible for the targeted recruitment of SIR proteins and the deacetylation of lysine 16 of histone H4. Previously, we found that Sir3 binds but does not compact nucleosomal arrays. Here we reconstitute chromatin fibers with the complete complement of SIR proteins and use sedimentation velocity, molecular modeling, and atomic force microscopy to characterize the stoichiometry and conformation of SIR chromatin fibers. In contrast to fibers with Sir3 alone, our results demonstrate that SIR arrays are highly compact. Strikingly, the condensed structure of SIR heterochromatin fibers requires both the integrity of H4K16 and an interaction between Sir3 and Sir4. We propose a model in which a dimer of Sir3 bridges and stabilizes two adjacent nucleosomes, while a Sir2-4 heterotetramer interacts with Sir3 associated with a nucleosomal trimer, driving fiber compaction.
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Affiliation(s)
- Sarah G Swygert
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Subhadip Senapati
- Center for Single Molecule Biophysics, Biodesign Institute, Arizona State University, Tempe, AZ 85287
| | - Mehmet F Bolukbasi
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Scot A Wolfe
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Stuart Lindsay
- Center for Single Molecule Biophysics, Biodesign Institute, Arizona State University, Tempe, AZ 85287
| | - Craig L Peterson
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605;
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18
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Hocher A, Ruault M, Kaferle P, Descrimes M, Garnier M, Morillon A, Taddei A. Expanding heterochromatin reveals discrete subtelomeric domains delimited by chromatin landscape transitions. Genome Res 2018; 28:1867-1881. [PMID: 30355601 PMCID: PMC6280759 DOI: 10.1101/gr.236554.118] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 10/20/2018] [Indexed: 01/20/2023]
Abstract
The eukaryotic genome is divided into chromosomal domains of heterochromatin and euchromatin. Transcriptionally silent heterochromatin is found at subtelomeric regions, leading to the telomeric position effect (TPE) in yeast, fly, and human. Heterochromatin generally initiates and spreads from defined loci, and diverse mechanisms prevent the ectopic spread of heterochromatin into euchromatin. Here, we overexpressed the silencing factor Sir3 at varying levels in yeast and found that Sir3 spreads into extended silent domains (ESDs), eventually reaching saturation at subtelomeres. We observed the spread of Sir3 into subtelomeric domains associated with specific histone marks in wild-type cells, and stopping at zones of histone mark transitions including H3K79 trimethylation levels. Our study shows that the conserved H3K79 methyltransferase Dot1 is essential in restricting Sir3 spread beyond ESDs, thus ensuring viability upon overexpression of Sir3. Last, our analyses of published data demonstrate how ESDs unveil uncharacterized discrete domains isolating structural and functional subtelomeric features from the rest of the genome. Our work offers a new approach on how to separate subtelomeres from the core chromosome.
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Affiliation(s)
- Antoine Hocher
- Institut Curie, PSL Research University, CNRS, UMR3664, F-75005 Paris, France.,Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR3664, F-75005 Paris, France
| | - Myriam Ruault
- Institut Curie, PSL Research University, CNRS, UMR3664, F-75005 Paris, France.,Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR3664, F-75005 Paris, France
| | - Petra Kaferle
- Institut Curie, PSL Research University, CNRS, UMR3664, F-75005 Paris, France.,Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR3664, F-75005 Paris, France
| | - Marc Descrimes
- Institut Curie, PSL Research University, CNRS, UMR3664, F-75005 Paris, France.,Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR3664, F-75005 Paris, France
| | - Mickaël Garnier
- Institut Curie, PSL Research University, CNRS, UMR3664, F-75005 Paris, France.,Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR3664, F-75005 Paris, France
| | - Antonin Morillon
- Institut Curie, PSL Research University, CNRS, UMR3664, F-75005 Paris, France.,Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR3664, F-75005 Paris, France
| | - Angela Taddei
- Institut Curie, PSL Research University, CNRS, UMR3664, F-75005 Paris, France.,Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR3664, F-75005 Paris, France
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19
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Chromatin Loop Formation Induced by a Subtelomeric Protosilencer Represses EPA Genes in Candida glabrata. Genetics 2018; 210:113-128. [PMID: 30002080 DOI: 10.1534/genetics.118.301202] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 07/09/2018] [Indexed: 01/05/2023] Open
Abstract
Adherence, an important virulence factor, is mediated by the EPA (Epithelial Adhesin) genes in the opportunistic pathogen Candida glabrata Expression of adhesin-encoding genes requires tight regulation to respond to harsh environmental conditions within the host. The majority of EPA genes are localized in subtelomeric regions regulated by subtelomeric silencing, which depends mainly on Rap1 and the Sir proteins. In vitro adhesion to epithelial cells is primarily mediated by Epa1. EPA1 forms a cluster with EPA2 and EPA3 in the right telomere of chromosome E (E-R). This telomere contains a cis-acting regulatory element, the protosilencer Sil2126 between EPA3 and the telomere. Interestingly, Sil2126 is only active in the context of its native telomere. Replacement of the intergenic regions between EPA genes in E-R revealed that cis-acting elements between EPA2 and EPA3 are required for Sil2126 activity when placed 32 kb away from the telomere (Sil@-32kb). Sil2126 contains several putative binding sites for Rap1 and Abf1, and its activity depends on these proteins. Indeed, Sil2126 binds Rap1 and Abf1 at its native position and also when inserted at -32 kb, a silencing-free environment in the parental strain. In addition, we found that Sil@-32kb and Sil2126 at its native position can physically interact with the intergenic regions between EPA1-EPA2 and EPA2-EPA3 respectively, by chromosome conformation capture assays. We speculate that Rap1 and Abf1 bound to Sil2126 can recruit the Silent Information Regulator complex, and together mediate silencing in this region, probably through the formation of a chromatin loop.
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20
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Leiva-Peláez O, Gutiérrez-Escobedo G, López-Fuentes E, Cruz-Mora J, De Las Peñas A, Castaño I. Molecular characterization of the silencing complex SIR in Candida glabrata hyperadherent clinical isolates. Fungal Genet Biol 2018; 118:21-31. [PMID: 29857197 DOI: 10.1016/j.fgb.2018.05.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 05/16/2018] [Accepted: 05/28/2018] [Indexed: 11/30/2022]
Abstract
An important virulence factor for the fungal pathogen Candida glabrata is the ability to adhere to the host cells, which is mediated by the expression of adhesins. Epa1 is responsible for ∼95% of the in vitro adherence to epithelial cells and is the founding member of the Epa family of adhesins. The majority of EPA genes are localized close to different telomeres, which causes transcriptional repression due to subtelomeric silencing. In C. glabrata there are three Sir proteins (Sir2, Sir3 and Sir4) that are essential for subtelomeric silencing. Among a collection of 79 clinical isolates, some display a hyperadherent phenotype to epithelial cells compared to our standard laboratory strain, BG14. These isolates also express several subtelomeric EPA genes simultaneously. We cloned the SIR2, SIR3 and SIR4 genes from the hyperadherent isolates and from the BG14 and the sequenced strain CBS138 in a replicative vector to complement null mutants in each of these genes in the BG14 background. All the SIR2 and SIR4 alleles tested from selected hyper-adherent isolates were functional and efficient to silence a URA3 reporter gene inserted in a subtelomeric region. The SIR3 alleles from these isolates were also functional, except the allele from isolate MC2 (sir3-MC2), which was not functional to silence the reporter and did not complement the hyperadherent phenotype of the BG14 sir3Δ. Consistently, sir3-MC2 allele is recessive to the SIR3 allele from BG14. Sir3 and Sir4 alleles from the hyperadherent isolates contain several polymorphisms and two of them are present in all the hyperadherent isolates analyzed. Instead, the Sir3 and Sir4 alleles from the BG14 and another non-adherent isolate do not display these polymorphisms and are identical to each other. The particular combination of polymorphisms in sir3-MC2 and in SIR4-MC2 could explain in part the hyperadherent phenotype displayed by this isolate.
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Affiliation(s)
- Osney Leiva-Peláez
- IPICYT, Instituto Potosino de Investigación Científica y Tecnológica, División de Biología Molecular, Camino a la Presa San José #2055, Col. Lomas 4a, San Luis Potosí 78216, Mexico
| | - Guadalupe Gutiérrez-Escobedo
- IPICYT, Instituto Potosino de Investigación Científica y Tecnológica, División de Biología Molecular, Camino a la Presa San José #2055, Col. Lomas 4a, San Luis Potosí 78216, Mexico
| | - Eunice López-Fuentes
- IPICYT, Instituto Potosino de Investigación Científica y Tecnológica, División de Biología Molecular, Camino a la Presa San José #2055, Col. Lomas 4a, San Luis Potosí 78216, Mexico
| | - José Cruz-Mora
- IPICYT, Instituto Potosino de Investigación Científica y Tecnológica, División de Biología Molecular, Camino a la Presa San José #2055, Col. Lomas 4a, San Luis Potosí 78216, Mexico
| | - Alejandro De Las Peñas
- IPICYT, Instituto Potosino de Investigación Científica y Tecnológica, División de Biología Molecular, Camino a la Presa San José #2055, Col. Lomas 4a, San Luis Potosí 78216, Mexico
| | - Irene Castaño
- IPICYT, Instituto Potosino de Investigación Científica y Tecnológica, División de Biología Molecular, Camino a la Presa San José #2055, Col. Lomas 4a, San Luis Potosí 78216, Mexico.
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21
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Zukowski A, Johnson AM. The interplay of histone H2B ubiquitination with budding and fission yeast heterochromatin. Curr Genet 2018; 64:799-806. [PMID: 29464330 DOI: 10.1007/s00294-018-0812-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 02/13/2018] [Accepted: 02/14/2018] [Indexed: 12/12/2022]
Abstract
Mono-ubiquitinated histone H2B (H2B-Ub) is important for chromatin regulation of transcription, chromatin assembly, and also influences heterochromatin. In this review, we discuss the effects of H2B-Ub from nucleosome to higher-order chromatin structure. We then assess what is currently known of the role of H2B-Ub in heterochromatic silencing in budding and fission yeasts (S. cerevisiae and S. pombe), which have distinct silencing mechanisms. In budding yeast, the SIR complex initiates heterochromatin assembly with the aid of a H2B-Ub deubiquitinase, Ubp10. In fission yeast, the RNAi-dependent pathway initiates heterochromatin in the context of low H2B-Ub. We examine how the different silencing machineries overcome the challenge of H2B-Ub chromatin and highlight the importance of using these microorganisms to further our understanding of H2B-Ub in heterochromatic silencing pathways.
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Affiliation(s)
- Alexis Zukowski
- Department of Biochemistry and Molecular Genetics, University of Colorado, Denver - School of Medicine, 12801 E. 17th Ave., Aurora, CO, 80045, USA
| | - Aaron M Johnson
- Department of Biochemistry and Molecular Genetics, University of Colorado, Denver - School of Medicine, 12801 E. 17th Ave., Aurora, CO, 80045, USA.
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22
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Zukowski A, Al-Afaleq NO, Duncan ED, Yao T, Johnson AM. Recruitment and allosteric stimulation of a histone-deubiquitinating enzyme during heterochromatin assembly. J Biol Chem 2017; 293:2498-2509. [PMID: 29288197 DOI: 10.1074/jbc.ra117.000498] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 12/22/2017] [Indexed: 02/02/2023] Open
Abstract
Heterochromatin formation in budding yeast is regulated by the silent information regulator (SIR) complex. The SIR complex comprises the NAD-dependent deacetylase Sir2, the scaffolding protein Sir4, and the nucleosome-binding protein Sir3. Transcriptionally active regions present a challenge to SIR complex-mediated de novo heterochromatic silencing due to the presence of antagonistic histone post-translational modifications, including acetylation and methylation. Methylation of histone H3K4 and H3K79 is dependent on monoubiquitination of histone H2B (H2B-Ub). The SIR complex cannot erase H2B-Ub or histone methylation on its own. The deubiquitinase (DUB) Ubp10 is thought to promote heterochromatic silencing by maintaining low H2B-Ub at sub-telomeres. Here, we biochemically characterized the interactions between Ubp10 and the SIR complex machinery. We demonstrate that a direct interaction between Ubp10 and the Sir2/4 sub-complex facilitates Ubp10 recruitment to chromatin via a co-assembly mechanism. Using hydrolyzable H2B-Ub analogs, we show that Ubp10 activity is lower on nucleosomes compared with H2B-Ub in solution. We find that Sir2/4 stimulates Ubp10 DUB activity on nucleosomes, likely through a combination of targeting and allosteric regulation. This coupling mechanism between the silencing machinery and its DUB partner allows erasure of active PTMs and the de novo transition of a transcriptionally active DNA region to a silent chromatin state.
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Affiliation(s)
- Alexis Zukowski
- From the Department of Biochemistry and Molecular Genetics and.,Molecular Biology Program, University of Colorado, Denver-Anschutz Medical Campus, Aurora, Colorado 80045 and
| | - Nouf Omar Al-Afaleq
- the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Emily D Duncan
- From the Department of Biochemistry and Molecular Genetics and.,Molecular Biology Program, University of Colorado, Denver-Anschutz Medical Campus, Aurora, Colorado 80045 and
| | - Tingting Yao
- the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Aaron M Johnson
- From the Department of Biochemistry and Molecular Genetics and .,Molecular Biology Program, University of Colorado, Denver-Anschutz Medical Campus, Aurora, Colorado 80045 and
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23
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Mulla WA, Seidel CW, Zhu J, Tsai HJ, Smith SE, Singh P, Bradford WD, McCroskey S, Nelliat AR, Conkright J, Peak A, Malanowski KE, Perera AG, Li R. Aneuploidy as a cause of impaired chromatin silencing and mating-type specification in budding yeast. eLife 2017; 6:27991. [PMID: 28841138 PMCID: PMC5779231 DOI: 10.7554/elife.27991] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 08/24/2017] [Indexed: 01/12/2023] Open
Abstract
Aneuploidy and epigenetic alterations have long been associated with carcinogenesis, but it was unknown whether aneuploidy could disrupt the epigenetic states required for cellular differentiation. In this study, we found that ~3% of random aneuploid karyotypes in yeast disrupt the stable inheritance of silenced chromatin during cell proliferation. Karyotype analysis revealed that this phenotype was significantly correlated with gains of chromosomes III and X. Chromosome X disomy alone was sufficient to disrupt chromatin silencing and yeast mating-type identity as indicated by a lack of growth response to pheromone. The silencing defect was not limited to cryptic mating type loci and was associated with broad changes in histone modifications and chromatin localization of Sir2 histone deacetylase. The chromatin-silencing defect of disome X can be partially recapitulated by an extra copy of several genes on chromosome X. These results suggest that aneuploidy can directly cause epigenetic instability and disrupt cellular differentiation.
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Affiliation(s)
- Wahid A Mulla
- Department of Cell Biology, Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Medicine, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Chris W Seidel
- Stowers Institute for Medical Research, Missouri, United States
| | - Jin Zhu
- Department of Cell Biology, Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Hung-Ji Tsai
- Department of Cell Biology, Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Sarah E Smith
- Stowers Institute for Medical Research, Missouri, United States
| | - Pushpendra Singh
- Department of Cell Biology, Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, United States
| | | | - Scott McCroskey
- Stowers Institute for Medical Research, Missouri, United States
| | - Anjali R Nelliat
- Department of Cell Biology, Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, United States
| | | | - Allison Peak
- Stowers Institute for Medical Research, Missouri, United States
| | | | - Anoja G Perera
- Stowers Institute for Medical Research, Missouri, United States
| | - Rong Li
- Department of Cell Biology, Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, United States
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