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Wu K, Dhillon N, Bajor A, Abrahamsson S, Kamakaka RT. Yeast heterochromatin stably silences only weak regulatory elements by altering burst duration. Cell Rep 2024; 43:113983. [PMID: 38517895 PMCID: PMC11141299 DOI: 10.1016/j.celrep.2024.113983] [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: 08/24/2023] [Revised: 12/25/2023] [Accepted: 03/06/2024] [Indexed: 03/24/2024] Open
Abstract
Transcriptional silencing in Saccharomyces cerevisiae involves the generation of a chromatin state that stably represses transcription. Using multiple reporter assays, a diverse set of upstream activating sequence enhancers and core promoters were investigated for their susceptibility to silencing. We show that heterochromatin stably silences only weak and stress-induced regulatory elements but is unable to stably repress housekeeping gene regulatory elements, and the partial repression of these elements did not result in bistable expression states. Permutation analysis of enhancers and promoters indicates that both elements are targets of repression. Chromatin remodelers help specific regulatory elements to resist repression, most probably by altering nucleosome mobility and changing transcription burst duration. The strong enhancers/promoters can be repressed if silencer-bound Sir1 is increased. Together, our data suggest that the heterochromatic locus has been optimized to stably silence the weak mating-type gene regulatory elements but not strong housekeeping gene regulatory sequences.
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Affiliation(s)
- Kenneth Wu
- Department of MCD Biology, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Namrita Dhillon
- Department of MCD Biology, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Antone Bajor
- Electrical Engineering Department, Baskin School of Engineering, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Sara Abrahamsson
- Electrical Engineering Department, Baskin School of Engineering, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Rohinton T Kamakaka
- Department of MCD Biology, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA.
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2
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Kim JM, Carcamo CC, Jazani S, Xie Z, Feng XA, Yamadi M, Poyton M, Holland KL, Grimm JB, Lavis LD, Ha T, Wu C. Dynamic 1D search and processive nucleosome translocations by RSC and ISW2 chromatin remodelers. eLife 2024; 12:RP91433. [PMID: 38497611 PMCID: PMC10948146 DOI: 10.7554/elife.91433] [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] [Indexed: 03/19/2024] Open
Abstract
Eukaryotic gene expression is linked to chromatin structure and nucleosome positioning by ATP-dependent chromatin remodelers that establish and maintain nucleosome-depleted regions (NDRs) near transcription start sites. Conserved yeast RSC and ISW2 remodelers exert antagonistic effects on nucleosomes flanking NDRs, but the temporal dynamics of remodeler search, engagement, and directional nucleosome mobilization for promoter accessibility are unknown. Using optical tweezers and two-color single-particle imaging, we investigated the Brownian diffusion of RSC and ISW2 on free DNA and sparse nucleosome arrays. RSC and ISW2 rapidly scan DNA by one-dimensional hopping and sliding, respectively, with dynamic collisions between remodelers followed by recoil or apparent co-diffusion. Static nucleosomes block remodeler diffusion resulting in remodeler recoil or sequestration. Remarkably, both RSC and ISW2 use ATP hydrolysis to translocate mono-nucleosomes processively at ~30 bp/s on extended linear DNA under tension. Processivity and opposing push-pull directionalities of nucleosome translocation shown by RSC and ISW2 shape the distinctive landscape of promoter chromatin.
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Affiliation(s)
- Jee Min Kim
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Claudia C Carcamo
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Sina Jazani
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Zepei Xie
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Xinyu A Feng
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Maryam Yamadi
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Matthew Poyton
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Katie L Holland
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Jonathan B Grimm
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Luke D Lavis
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of MedicineBaltimoreUnited States
- Howard Hughes Medical InstituteBostonUnited States
| | - Carl Wu
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
- Department of Molecular Biology and Genetics, Johns Hopkins School of MedicineBaltimoreUnited States
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3
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Kim JM, Carcamo CC, Jazani S, Xie Z, Feng XA, Yamadi M, Poyton M, Holland KL, Grimm JB, Lavis LD, Ha T, Wu C. Dynamic 1D Search and Processive Nucleosome Translocations by RSC and ISW2 Chromatin Remodelers. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.06.13.544671. [PMID: 38293098 PMCID: PMC10827135 DOI: 10.1101/2023.06.13.544671] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Eukaryotic gene expression is linked to chromatin structure and nucleosome positioning by ATP-dependent chromatin remodelers that establish and maintain nucleosome-depleted regions (NDRs) near transcription start-sites. Conserved yeast RSC and ISW2 remodelers exert antagonistic effects on nucleosomes flanking NDRs, but the temporal dynamics of remodeler search, engagement and directional nucleosome mobilization for promoter accessibility are unknown. Using optical tweezers and 2-color single-particle imaging, we investigated the Brownian diffusion of RSC and ISW2 on free DNA and sparse nucleosome arrays. RSC and ISW2 rapidly scan DNA by one-dimensional hopping and sliding respectively, with dynamic collisions between remodelers followed by recoil or apparent co-diffusion. Static nucleosomes block remodeler diffusion resulting in remodeler recoil or sequestration. Remarkably, both RSC and ISW2 use ATP hydrolysis to translocate mono-nucleosomes processively at ~30 bp/sec on extended linear DNA under tension. Processivity and opposing push-pull directionalities of nucleosome translocation shown by RSC and ISW2 shape the distinctive landscape of promoter chromatin.
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Affiliation(s)
- Jee Min Kim
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Claudia C. Carcamo
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sina Jazani
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Zepei Xie
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Xinyu A. Feng
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Maryam Yamadi
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Matthew Poyton
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Katie L. Holland
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Jonathan B. Grimm
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Luke D. Lavis
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Howard Hughes Medical Institute, Boston, Massachusetts, USA
| | - Carl Wu
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Molecular Biology and Genetics, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA
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4
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Wu K, Dhillon N, Bajor A, Abrahamson S, Kamakaka RT. Yeast Heterochromatin Only Stably Silences Weak Regulatory Elements by Altering Burst Duration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.05.561072. [PMID: 37873261 PMCID: PMC10592971 DOI: 10.1101/2023.10.05.561072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
The interplay between nucleosomes and transcription factors leads to programs of gene expression. Transcriptional silencing involves the generation of a chromatin state that represses transcription and is faithfully propagated through DNA replication and cell division. Using multiple reporter assays, including directly visualizing transcription in single cells, we investigated a diverse set of UAS enhancers and core promoters for their susceptibility to heterochromatic gene silencing. These results show that heterochromatin only stably silences weak and stress induced regulatory elements but is unable to stably repress housekeeping gene regulatory elements and the partial repression did not result in bistable expression states. Permutation analysis of different UAS enhancers and core promoters indicate that both elements function together to determine the susceptibility of regulatory sequences to repression. Specific histone modifiers and chromatin remodellers function in an enhancer specific manner to aid these elements to resist repression suggesting that Sir proteins likely function in part by reducing nucleosome mobility. We also show that the strong housekeeping regulatory elements can be repressed if silencer bound Sir1 is increased, suggesting that Sir1 is a limiting component in silencing. Together, our data suggest that the heterochromatic locus has been optimized to stably silence the weak mating type gene regulatory elements but not strong housekeeping gene regulatory sequences which could help explain why these genes are often found at the boundaries of silenced domains.
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Affiliation(s)
- Kenneth Wu
- Department of MCD Biology, 1156 High Street, University of California, Santa Cruz, CA 95064 USA
| | - Namrita Dhillon
- Department of MCD Biology, 1156 High Street, University of California, Santa Cruz, CA 95064 USA
| | - Antone Bajor
- Electrical Engineering Department, Baskin School of Engineering, 1156 High Street, University of California, Santa Cruz, CA 95064 USA
| | - Sara Abrahamson
- Electrical Engineering Department, Baskin School of Engineering, 1156 High Street, University of California, Santa Cruz, CA 95064 USA
| | - Rohinton T. Kamakaka
- Department of MCD Biology, 1156 High Street, University of California, Santa Cruz, CA 95064 USA
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5
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Harris A, Ünal E. The transcriptional regulator Ume6 is a major driver of early gene expression during gametogenesis. Genetics 2023; 225:iyad123. [PMID: 37431893 PMCID: PMC10550318 DOI: 10.1093/genetics/iyad123] [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: 04/07/2023] [Revised: 06/07/2023] [Accepted: 06/23/2023] [Indexed: 07/12/2023] Open
Abstract
The process of gametogenesis is orchestrated by a dynamic gene expression program, where a vital subset constitutes the early meiotic genes. In budding yeast, the transcription factor Ume6 represses early meiotic gene expression during mitotic growth. However, during the transition from mitotic to meiotic cell fate, early meiotic genes are activated in response to the transcriptional regulator Ime1 through its interaction with Ume6. While it is known that binding of Ime1 to Ume6 promotes early meiotic gene expression, the mechanism of early meiotic gene activation remains elusive. Two competing models have been proposed whereby Ime1 either forms an activator complex with Ume6 or promotes Ume6 degradation. Here, we resolve this controversy. First, we identify the set of genes that are directly regulated by Ume6, including UME6 itself. While Ume6 protein levels increase in response to Ime1, Ume6 degradation occurs much later in meiosis. Importantly, we found that depletion of Ume6 shortly before meiotic entry is detrimental to early meiotic gene activation and gamete formation, whereas tethering of Ume6 to a heterologous activation domain is sufficient to trigger early meiotic gene expression and produce viable gametes in the absence of Ime1. We conclude that Ime1 and Ume6 form an activator complex. While Ume6 is indispensable for early meiotic gene expression, Ime1 primarily serves as a transactivator for Ume6.
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Affiliation(s)
- Anthony Harris
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Elçin Ünal
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
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Zhu C, Iwase M, Li Z, Wang F, Quinet A, Vindigni A, Shao J. Profilin-1 regulates DNA replication forks in a context-dependent fashion by interacting with SNF2H and BOD1L. Nat Commun 2022; 13:6531. [PMID: 36319634 PMCID: PMC9626489 DOI: 10.1038/s41467-022-34310-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 10/21/2022] [Indexed: 12/04/2022] Open
Abstract
DNA replication forks are tightly controlled by a large protein network consisting of well-known core regulators and many accessory factors which remain functionally undefined. In this study, we report previously unknown nuclear functions of the actin-binding factor profilin-1 (PFN1) in DNA replication, which occur in a context-dependent fashion and require its binding to poly-L-proline (PLP)-containing proteins instead of actin. In unperturbed cells, PFN1 increases DNA replication initiation and accelerates fork progression by binding and stimulating the PLP-containing nucleosome remodeler SNF2H. Under replication stress, PFN1/SNF2H increases fork stalling and functionally collaborates with fork reversal enzymes to enable the over-resection of unprotected forks. In addition, PFN1 binds and functionally attenuates the PLP-containing fork protector BODL1 to increase the resection of a subset of stressed forks. Accordingly, raising nuclear PFN1 level decreases genome stability and cell survival during replication stress. Thus, PFN1 is a multi-functional regulator of DNA replication with exploitable anticancer potential.
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Affiliation(s)
- Cuige Zhu
- Divison of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Mari Iwase
- Divison of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Ziqian Li
- Divison of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Department of Microbial and Biochemical Pharmacy, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Faliang Wang
- Divison of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Annabel Quinet
- Divison of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- UMR Genetic Stability Stem Cells and Radiation, University of Paris and University of Paris-Saclay, INSERM, iRCM/IBFJ CEA, Fontenay-aux-Roses, France
| | - Alessandro Vindigni
- Divison of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Jieya Shao
- Divison of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA.
- Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO, 63110, USA.
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Hendy O, Serebreni L, Bergauer K, Muerdter F, Huber L, Nemčko F, Stark A. Developmental and housekeeping transcriptional programs in Drosophila require distinct chromatin remodelers. Mol Cell 2022; 82:3598-3612.e7. [PMID: 36113480 PMCID: PMC7614073 DOI: 10.1016/j.molcel.2022.08.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 04/13/2022] [Accepted: 08/17/2022] [Indexed: 01/21/2023]
Abstract
Gene transcription is a highly regulated process in all animals. In Drosophila, two major transcriptional programs, housekeeping and developmental, have promoters with distinct regulatory compatibilities and nucleosome organization. However, it remains unclear how the differences in chromatin structure relate to the distinct regulatory properties and which chromatin remodelers are required for these programs. Using rapid degradation of core remodeler subunits in Drosophila melanogaster S2 cells, we demonstrate that developmental gene transcription requires SWI/SNF-type complexes, primarily to maintain distal enhancer accessibility. In contrast, wild-type-level housekeeping gene transcription requires the Iswi and Ino80 remodelers to maintain nucleosome positioning and phasing at promoters. These differential remodeler dependencies relate to different DNA-sequence-intrinsic nucleosome affinities, which favor a default ON state for housekeeping but a default OFF state for developmental gene transcription. Overall, our results demonstrate how different transcription-regulatory strategies are implemented by DNA sequence, chromatin structure, and remodeler activity.
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Affiliation(s)
- Oliver Hendy
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna, Medical University of Vienna, 1030 Vienna, Austria
| | - Leonid Serebreni
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna, Medical University of Vienna, 1030 Vienna, Austria
| | - Katharina Bergauer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Felix Muerdter
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Lukas Huber
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Filip Nemčko
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna, Medical University of Vienna, 1030 Vienna, Austria
| | - Alexander Stark
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria; Medical University of Vienna, Vienna BioCenter (VBC), Vienna 1030, Austria.
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8
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Partitioned usage of chromatin remodelers by nucleosome-displacing factors. Cell Rep 2022; 40:111250. [PMID: 36001970 PMCID: PMC9422437 DOI: 10.1016/j.celrep.2022.111250] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/29/2022] [Accepted: 08/01/2022] [Indexed: 11/22/2022] Open
Abstract
Nucleosome-displacing-factors (NDFs) in yeast, similar to pioneer factors in higher eukaryotes, can open closed chromatin and generate nucleosome-depleted regions (NDRs). NDRs in yeast are also affected by ATP-dependent chromatin remodelers (CRs). However, how NDFs and CRs coordinate in nucleosome invasion and NDR formation is still unclear. Here, we design a high-throughput method to systematically study the interplay between NDFs and CRs. By combining an integrated synthetic oligonucleotide library with DNA methyltransferase-based, single-molecule nucleosome mapping, we measure the impact of CRs on NDRs generated by individual NDFs. We find that CRs are dispensable for nucleosome invasion by NDFs, and they function downstream of NDF binding to modulate the NDR length. A few CRs show high specificity toward certain NDFs; however, in most cases, CRs are recruited in a factor-nonspecific and NDR length-dependent manner. Overall, our study provides a framework to investigate how NDFs and CRs cooperate to regulate chromatin opening. Chromatin accessibility in yeast is regulated by nucleosome-displacing-factors (NDFs) and chromatin remodelers (CRs). Chen et al. show that NDFs first invade into nucleosomes and then recruit CRs to modulate the NDR length. NDF-specific and NDR length-dependent recruitment of CRs allow partitioned usage of CRs by NDFs.
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Wiles ET, Mumford CC, McNaught KJ, Tanizawa H, Selker EU. The ACF chromatin-remodeling complex is essential for Polycomb repression. eLife 2022; 11:e77595. [PMID: 35257662 PMCID: PMC9038196 DOI: 10.7554/elife.77595] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 03/03/2022] [Indexed: 11/13/2022] Open
Abstract
Establishing and maintaining appropriate gene repression is critical for the health and development of multicellular organisms. Histone H3 lysine 27 (H3K27) methylation is a chromatin modification associated with repressed facultative heterochromatin, but the mechanism of this repression remains unclear. We used a forward genetic approach to identify genes involved in transcriptional silencing of H3K27-methylated chromatin in the filamentous fungus Neurospora crassa. We found that the N. crassa homologs of ISWI (NCU03875) and ACF1 (NCU00164) are required for repression of a subset of H3K27-methylated genes and that they form an ACF chromatin-remodeling complex. This ACF complex interacts with chromatin throughout the genome, yet association with facultative heterochromatin is specifically promoted by the H3K27 methyltransferase, SET-7. H3K27-methylated genes that are upregulated when iswi or acf1 are deleted show a downstream shift of the +1 nucleosome, suggesting that proper nucleosome positioning is critical for repression of facultative heterochromatin. Our findings support a direct role of the ACF complex in Polycomb repression.
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Affiliation(s)
- Elizabeth T Wiles
- Institute of Molecular Biology, University of OregonEugeneUnited States
| | - Colleen C Mumford
- Institute of Molecular Biology, University of OregonEugeneUnited States
| | - Kevin J McNaught
- Institute of Molecular Biology, University of OregonEugeneUnited States
| | - Hideki Tanizawa
- Institute of Molecular Biology, University of OregonEugeneUnited States
| | - Eric U Selker
- Institute of Molecular Biology, University of OregonEugeneUnited States
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