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Lorch Y, Kornberg RD, Maier-Davis B. Role of the histone tails in histone octamer transfer. Nucleic Acids Res 2023; 51:3671-3678. [PMID: 36772826 PMCID: PMC10164550 DOI: 10.1093/nar/gkad079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/17/2023] [Accepted: 01/25/2023] [Indexed: 02/12/2023] Open
Abstract
The exceptionally high positive charge of the histones, concentrated in the N- and C-terminal tails, is believed to contribute to the stability of the nucleosome by neutralizing the negative charge of the nucleosomal DNA. We find, on the contrary, that the high positive charge contributes to instability, performing an essential function in chromatin remodeling. We show that the tails are required for removal of the histone octamer by the RSC chromatin remodeling complex, and this function is not due to direct RSC-tail interaction. We also show that the tails are required for histone octamer transfer from nucleosomes to DNA, and this activity of the tails is a consequence of their positive charge. Thus, the histone tails, intrinsically disordered protein regions, perform a critical role in chromatin structure and transcription, unrelated to their well-known role in regulation through posttranscriptional modification.
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Affiliation(s)
- Yahli Lorch
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Roger D Kornberg
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Barbara Maier-Davis
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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Structure of SWI/SNF chromatin remodeller RSC bound to a nucleosome. Nature 2020; 579:448-451. [PMID: 32188943 PMCID: PMC7093204 DOI: 10.1038/s41586-020-2088-0] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 01/08/2020] [Indexed: 12/25/2022]
Abstract
Chromatin remodelling complexes of the SWI/SNF family function in the formation of nucleosome-depleted, transcriptionally active promoter regions (NDRs)1,2. The essential Saccharomyces cerevisiae SWI/SNF complex RSC3 contains 16 subunits, including the ATP-dependent DNA translocase Sth14,5. RSC removes nucleosomes from promoter regions6,7 and positions the specialized +1 and –1 nucleosomes that flank NDRs8,9. Here, we present the cryo-EM structure of RSC in complex with a nucleosome substrate. The structure reveals that RSC forms five protein modules and suggests key features of the remodelling mechanism. The body module serves as a scaffold for the four flexible modules that we call DNA-interacting, ATPase, arm and ARP modules. The DNA-interacting module binds extra-nucleosomal DNA and is involved in the recognition of promoter DNA elements8,10,11 that influence RSC functionality12. The ATPase and arm modules sandwich the nucleosome disc with their ‘SnAC’ and ‘finger’ elements, respectively. The translocase motor of the ATPase module engages with the edge of the nucleosome at superhelical location +2. The mobile ARP module may modulate translocase-nucleosome interactions to regulate RSC activity5. The RSC-nucleosome structure provides a basis for understanding NDR formation and the structure and function of human SWI/SNF complexes that are frequently mutated in cancer13.
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Cakiroglu A, Clapier CR, Ehrensberger AH, Darbo E, Cairns BR, Luscombe NM, Svejstrup JQ. Genome-wide reconstitution of chromatin transactions reveals that RSC preferentially disrupts H2AZ-containing nucleosomes. Genome Res 2019; 29:988-998. [PMID: 31097474 PMCID: PMC6581049 DOI: 10.1101/gr.243139.118] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 05/08/2019] [Indexed: 12/03/2022]
Abstract
Chromatin transactions are typically studied in vivo, or in vitro using artificial chromatin lacking the epigenetic complexity of the natural material. Attempting to bridge the gap between these approaches, we established a system for isolating the yeast genome as a library of mononucleosomes harboring the natural epigenetic signature, suitable for biochemical manipulation. Combined with deep sequencing, this library was used to investigate the stability of individual nucleosomes and, as proof of principle, the nucleosome preference of the chromatin remodeling complex, RSC. This approach uncovered a distinct preference of RSC for nucleosomes derived from regions with a high density of histone variant H2AZ, and this preference is indeed markedly diminished using nucleosomes from cells lacking H2AZ. The preference for H2AZ remodeling/nucleosome ejection can also be reconstituted with recombinant nucleosome arrays. Together, our data indicate that, despite being separated from their genomic context, individual nucleosomes can retain their original identity as promoter- or transcription start site (TSS)-nucleosomes. Besides shedding new light on substrate preference of the chromatin remodeler RSC, the simple experimental system outlined here should be generally applicable to the study of chromatin transactions.
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Affiliation(s)
- Aylin Cakiroglu
- Bioinformatics and Computational Biology Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Cedric R Clapier
- Department of Oncological Sciences, Huntsman Cancer Institute, and Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA
| | - Andreas H Ehrensberger
- Bioinformatics and Computational Biology Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Elodie Darbo
- Bioinformatics and Computational Biology Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Bradley R Cairns
- Department of Oncological Sciences, Huntsman Cancer Institute, and Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA
| | - Nicholas M Luscombe
- Bioinformatics and Computational Biology Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
- UCL Genetics Institute, Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
| | - Jesper Q Svejstrup
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
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Lorch Y, Maier-Davis B, Kornberg RD. Histone Acetylation Inhibits RSC and Stabilizes the +1 Nucleosome. Mol Cell 2018; 72:594-600.e2. [PMID: 30401433 PMCID: PMC6290470 DOI: 10.1016/j.molcel.2018.09.030] [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] [Received: 03/12/2018] [Revised: 08/09/2018] [Accepted: 09/20/2018] [Indexed: 12/12/2022]
Abstract
The +1 nucleosome of yeast genes, within which reside transcription start sites, is characterized by histone acetylation, by the displacement of an H2A-H2B dimer, and by a persistent association with the RSC chromatin-remodeling complex. Here we demonstrate the interrelationship of these characteristics and the conversion of a nucleosome to the +1 state in vitro. Contrary to expectation, acetylation performs an inhibitory role, preventing the removal of a nucleosome by RSC. Inhibition is due to both enhanced RSC-histone interaction and diminished histone-chaperone interaction. Acetylation does not prevent all RSC activity, because stably bound RSC removes an H2A-H2B dimer on a timescale of seconds in an irreversible manner.
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Affiliation(s)
- Yahli Lorch
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Barbara Maier-Davis
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Roger D Kornberg
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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Abstract
Chromatin isolated from the chromosomal locus of the PHO5 gene of yeast in a transcriptionally repressed state was transcribed with 12 pure proteins (80 polypeptides): RNA polymerase II, six general transcription factors, TFIIS, the Pho4 gene activator protein, and the SAGA, SWI/SNF, and Mediator complexes. Contrary to expectation, a nucleosome occluding the TATA box and transcription start sites did not impede transcription but rather, enhanced it: the level of chromatin transcription was at least sevenfold greater than that of naked DNA, and chromatin gave patterns of transcription start sites closely similar to those occurring in vivo, whereas naked DNA gave many aberrant transcripts. Both histone acetylation and trimethylation of H3K4 (H3K4me3) were important for chromatin transcription. The nucleosome, long known to serve as a general gene repressor, thus also performs an important positive role in transcription.
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Lorch Y, Maier-Davis B, Kornberg RD. Role of DNA sequence in chromatin remodeling and the formation of nucleosome-free regions. Genes Dev 2015; 28:2492-7. [PMID: 25403179 PMCID: PMC4233242 DOI: 10.1101/gad.250704.114] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
AT-rich DNA is concentrated in the nucleosome-free regions (NFRs) associated with transcription start sites of most genes. Lorch et al. find that the AT-rich sequences present in many NFRs have little effect on the stability of nucleosomes. These sequences instead facilitate the removal of nucleosomes by the RSC chromatin remodeling complex. RSC activity is stimulated by AT-rich sequences in nucleosomes and inhibited by competition with AT-rich DNA. AT-rich DNA is concentrated in the nucleosome-free regions (NFRs) associated with transcription start sites of most genes. We tested the hypothesis that AT-rich DNA engenders NFR formation by virtue of its rigidity and consequent exclusion of nucleosomes. We found that the AT-rich sequences present in many NFRs have little effect on the stability of nucleosomes. Rather, these sequences facilitate the removal of nucleosomes by the RSC chromatin remodeling complex. RSC activity is stimulated by AT-rich sequences in nucleosomes and inhibited by competition with AT-rich DNA. RSC may remove NFR nucleosomes without effect on adjacent ORF nucleosomes. Our findings suggest that many NFRs are formed and maintained by an active mechanism involving the ATP-dependent removal of nucleosomes rather than a passive mechanism due to the intrinsic instability of nucleosomes on AT-rich DNA sequences.
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Affiliation(s)
- Yahli Lorch
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Barbara Maier-Davis
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Roger D Kornberg
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305, USA
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Duan MR, Smerdon MJ. Histone H3 lysine 14 (H3K14) acetylation facilitates DNA repair in a positioned nucleosome by stabilizing the binding of the chromatin Remodeler RSC (Remodels Structure of Chromatin). J Biol Chem 2014; 289:8353-63. [PMID: 24515106 DOI: 10.1074/jbc.m113.540732] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Histone H3 acetylation is induced by UV damage in yeast and may play an important role in regulating the repair of UV photolesions in nucleosome-loaded genomic loci. However, it remains elusive how H3 acetylation facilitates repair. We generated a strongly positioned nucleosome containing homogeneously acetylated H3 at Lys-14 (H3K14ac) and investigated possible mechanisms by which H3K14 acetylation modulates repair. We show that H3K14ac does not alter nucleosome unfolding dynamics or enhance the repair of UV-induced cyclobutane pyrimidine dimers by UV photolyase. Importantly, however, nucleosomes with H3K14ac have a higher affinity for purified chromatin remodeling complex RSC (Remodels the Structure of Chromatin) and show greater cyclobutane pyrimidine dimer repair compared with unacetylated nucleosomes. Our study indicates that, by anchoring RSC, H3K14 acetylation plays an important role in the unfolding of strongly positioned nucleosomes during repair of UV damage.
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Affiliation(s)
- Ming-Rui Duan
- From Biochemistry and Biophysics, School of Molecular Biosciences, Washington State University, Pullman, Washington 99164-7520
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Abstract
Results from biochemical and structural studies of the RSC chromatin-remodeling complex prompt a proposal for the remodeling mechanism: RSC binding to the nucleosome releases the DNA from the histone surface and initiates DNA translocation (through one or a small number of DNA base pairs); ATP binding completes translocation, and ATP hydrolysis resets the system. Binding energy thus plays a central role in the remodeling process. RSC may disrupt histone-DNA contacts by affecting histone octamer conformation and through extensive interaction with the DNA. Bulging of the DNA from the octamer surface is possible, and twisting is unavoidable, but neither is the basis of remodeling.
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Abstract
Short DNA fragments containing single, uniquely positioned nucleosome cores have been extensively employed as simple model experimental systems for analysis of many intranuclear processes, including binding of proteins to nucleosomes, transcription, DNA repair and ATP-dependent chromatin remodeling. In many cases such simple model templates faithfully recapitulate numerous important aspects of these processes. Here we describe several recently developed procedures for obtaining and analysis of mononucleosomes that are uniquely positioned on 150-600 bp DNA fragments.
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Lorch Y, Maier-Davis B, Kornberg RD. Chromatin remodeling by nucleosome disassembly in vitro. Proc Natl Acad Sci U S A 2006; 103:3090-3. [PMID: 16492771 PMCID: PMC1413907 DOI: 10.1073/pnas.0511050103] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The RSC chromatin-remodeling complex completely disassembles a nucleosome in the presence of the histone chaperone Nap1 and ATP. Disassembly occurs in a stepwise manner, with the removal of H2A/H2B dimers, followed by the rest of the histones and the release of naked DNA. RSC and related chromatin-remodeling complexes may be responsible for the removal of promoter nucleosomes during transcriptional activation in vivo.
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Affiliation(s)
- Yahli Lorch
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126
| | - Barbara Maier-Davis
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126
| | - Roger D. Kornberg
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126
- *To whom correspondence should be addressed. E-mail:
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Lorch Y, Davis B, Kornberg RD. Chromatin remodeling by DNA bending, not twisting. Proc Natl Acad Sci U S A 2005; 102:1329-32. [PMID: 15677336 PMCID: PMC546017 DOI: 10.1073/pnas.0409413102] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Single-stranded regions (gaps) in nucleosomal DNA interfere with action of the RSC chromatin-remodeling complex, monitored by exposure of restriction endonuclease cutting sites. Single-strand breaks (nicks) in the DNA, by contrast, have no effect. Gaps on one side of the cutting site are inhibitory, but gaps on the other side are not. A gap >100 bp from the cutting site is as effective as a gap <20 bp from the site. These findings suggest a remodeling process involving bending, but not twisting, of the DNA and further point to the propagation of a bent region (loop or bulge) from one end of the nucleosome to the other.
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Affiliation(s)
- Yahli Lorch
- Department of Structural Biology, School of Medicine, Stanford University, Stanford, CA 94305, USA
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