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Zaret K. Learning from chromatin reconstitution: Pioneer factors enabling nucleosome remodelers. Mol Cell 2024; 84:1817. [PMID: 38604174 DOI: 10.1016/j.molcel.2024.03.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 03/08/2024] [Accepted: 03/19/2024] [Indexed: 04/13/2024]
Affiliation(s)
- Ken Zaret
- Institute for Regenerative Medicine, Epigenetics Institute, and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-5157, USA.
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2
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Ahmad K, Brahma S, Henikoff S. Response to "Learning from chromatin reconstitution: Pioneering factors enabling nucleosome remodelers". Mol Cell 2024; 84:1818. [PMID: 38604173 DOI: 10.1016/j.molcel.2024.03.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/11/2024] [Accepted: 03/19/2024] [Indexed: 04/13/2024]
Affiliation(s)
- Kami Ahmad
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Sandipan Brahma
- University of Nebraska Medical Center, Department of Genetics, Cell Biology & Anatomy, Omaha, NE, USA
| | - Steven Henikoff
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA.
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3
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Frederick MA, Williamson KE, Fernandez Garcia M, Ferretti MB, McCarthy RL, Donahue G, Luzete Monteiro E, Takenaka N, Reynaga J, Kadoch C, Zaret KS. A pioneer factor locally opens compacted chromatin to enable targeted ATP-dependent nucleosome remodeling. Nat Struct Mol Biol 2023; 30:31-37. [PMID: 36536103 PMCID: PMC10004348 DOI: 10.1038/s41594-022-00886-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 11/03/2022] [Indexed: 12/24/2022]
Abstract
To determine how different pioneer transcription factors form a targeted, accessible nucleosome within compacted chromatin and collaborate with an ATP-dependent chromatin remodeler, we generated nucleosome arrays in vitro with a central nucleosome containing binding sites for the hematopoietic E-Twenty Six (ETS) factor PU.1 and Basic Leucine Zipper (bZIP) factors C/EBPα and C/EBPβ. Our long-read sequencing reveals that each factor can expose a targeted nucleosome on linker histone-compacted arrays, but with different nuclease sensitivity patterns. The DNA binding domain of PU.1 binds mononucleosomes, but requires an additional intrinsically disordered domain to bind and open compacted chromatin. The canonical mammalian SWI/SNF (cBAF) remodeler was unable to act upon two forms of locally open chromatin unless cBAF was enabled by a separate transactivation domain of PU.1. cBAF potentiates the PU.1 DNA binding domain to weakly open chromatin in the absence of the PU.1 disordered domain. Our findings reveal a hierarchy by which chromatin is opened and show that pioneer factors can provide specificity for action by nucleosome remodelers.
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Affiliation(s)
- Megan A Frederick
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kaylyn E Williamson
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
| | - Meilin Fernandez Garcia
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Max B Ferretti
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ryan L McCarthy
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Greg Donahue
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Edgar Luzete Monteiro
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
| | - Naomi Takenaka
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Janice Reynaga
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Cigall Kadoch
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
| | - Kenneth S Zaret
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Department Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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4
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Amigo R, Farkas C, Gidi C, Hepp MI, Cartes N, Tarifeño E, Workman JL, Gutiérrez JL. The linker histone Hho1 modulates the activity of ATP-dependent chromatin remodeling complexes. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2022; 1865:194781. [PMID: 34963628 DOI: 10.1016/j.bbagrm.2021.194781] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 11/30/2021] [Accepted: 12/12/2021] [Indexed: 02/07/2023]
Abstract
Diverse factors play roles in chromatin dynamics, including linker proteins. Among them are high mobility group (HMG) box family proteins and linker histones. In the yeast Saccharomyces cerevisiae, Hmo1 has been identified as an HMG-box protein. This protein displays properties that are in agreement with this allocation. However, a number of studies have postulated that Hmo1 functions as a linker histone in yeast. On the other hand, when discovered, the Hho1 protein was identified as a linker histone. While multiple studies support this classification, some findings point to characteristics of Hho1 that are dissimilar to those commonly assigned to linker histones. In order to better understand the roles played by Hmo1 and Hho1 in chromatin dynamics and transcriptional regulation, we performed several analyses directly comparing these two proteins. Our analyses of genome-wide binding profiles support the belonging of Hmo1 to the HMGB family and Hho1 to the linker histones family. Interestingly, by performing protein-protein interaction analyses we found that both Hmo1 and Hho1 display physical interaction with the ATP-dependent chromatin remodeling complexes RSC, ISW1a and SWI/SNF. Moreover, by carrying out nucleosome remodeling assays, we found that both proteins stimulate the activity of the ISW1a complex. However, in the case of RSC, Hmo1 and Hho1 displayed differential properties, with Hho1 mainly showing an inhibitory effect. Our results are in agreement with the opposite roles played by RSC and ISW1a in chromatin dynamics and transcriptional regulation, and expand the view for the roles played by Hho1 and linker histones.
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Affiliation(s)
- Roberto Amigo
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, Concepción 4070043, Chile
| | - Carlos Farkas
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, Concepción 4070043, Chile
| | - Cristian Gidi
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, Concepción 4070043, Chile
| | - Matias I Hepp
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, Concepción 4070043, Chile
| | - Natalia Cartes
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, Concepción 4070043, Chile
| | - Estefanía Tarifeño
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, Concepción 4070043, Chile
| | - Jerry L Workman
- Stowers Institute for Medical Research, 1000 E 50(th) Street, Kansas City, MO 64110, USA
| | - José L Gutiérrez
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, Concepción 4070043, Chile.
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5
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Abstract
Pioneer transcription factors have the intrinsic biochemical ability to scan partial DNA sequence motifs that are exposed on the surface of a nucleosome and thus access silent genes that are inaccessible to other transcription factors. Pioneer factors subsequently enable other transcription factors, nucleosome remodeling complexes, and histone modifiers to engage chromatin, thereby initiating the formation of an activating or repressive regulatory sequence. Thus, pioneer factors endow the competence for fate changes in embryonic development, are essential for cellular reprogramming, and rewire gene networks in cancer cells. Recent studies with reconstituted nucleosomes in vitro and chromatin binding in vivo reveal that pioneer factors can directly perturb nucleosome structure and chromatin accessibility in different ways. This review focuses on our current understanding of the mechanisms by which pioneer factors initiate gene network changes and will ultimately contribute to our ability to control cell fates at will.
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Affiliation(s)
- Kenneth S Zaret
- Institute for Regenerative Medicine, Epigenetics Institute, Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-5157, USA;
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6
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Gene network transitions in embryos depend upon interactions between a pioneer transcription factor and core histones. Nat Genet 2020; 52:418-427. [PMID: 32203463 PMCID: PMC7901023 DOI: 10.1038/s41588-020-0591-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 02/14/2020] [Indexed: 12/17/2022]
Abstract
Gene network transitions in embryos and other fate-changing contexts involve combinations of transcription factors. A subset of fate-changing transcription factors act as pioneers; they scan and target nucleosomal DNA and initiate cooperative events that can open the local chromatin. But a gap has remained in understanding how molecular interactions with the nucleosome contribute to the chromatin-opening phenomenon. Here we identified a short alpha-helical region, conserved among FOXA pioneer factors, that interacts with core histones and contributes to chromatin opening in vitro. The same domain is involved in chromatin opening in early mouse embryos for normal development. Thus, local opening of chromatin by interactions between pioneer factors and core histones promotes genetic programming.
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7
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Glaich O, Leader Y, Lev Maor G, Ast G. Histone H1.5 binds over splice sites in chromatin and regulates alternative splicing. Nucleic Acids Res 2019; 47:6145-6159. [PMID: 31076740 PMCID: PMC6614845 DOI: 10.1093/nar/gkz338] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 04/17/2019] [Accepted: 04/27/2019] [Indexed: 12/11/2022] Open
Abstract
Chromatin organization and epigenetic markers influence splicing, though the magnitudes of these effects and the mechanisms are largely unknown. Here, we demonstrate that linker histone H1.5 influences mRNA splicing. We observed that linker histone H1.5 binds DNA over splice sites of short exons in human lung fibroblasts (IMR90 cells). We found that association of H1.5 with these splice sites correlated with the level of inclusion of alternatively spliced exons. Exons marked by H1.5 had more RNA polymerase II (RNAP II) stalling near the 3' splice site than did exons not associated with H1.5. In cells depleted of H1.5, we showed that the inclusion of five exons evaluated decreased and that RNAP II levels over these exons were also reduced. Our findings indicate that H1.5 is involved in regulation of splice site selection and alternative splicing, a function not previously demonstrated for linker histones.
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Affiliation(s)
- Ohad Glaich
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Yodfat Leader
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Galit Lev Maor
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Gil Ast
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel
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8
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Mishra LN, Hayes JJ. A nucleosome-free region locally abrogates histone H1-dependent restriction of linker DNA accessibility in chromatin. J Biol Chem 2018; 293:19191-19200. [PMID: 30373774 DOI: 10.1074/jbc.ra118.005721] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/16/2018] [Indexed: 12/20/2022] Open
Abstract
Eukaryotic genomes are packaged into linker-oligonucleosome assemblies, providing compaction of genomic DNA and contributing to gene regulation and genome integrity. To define minimal requirements for initial steps in the transition of compact, closed chromatin to a transcriptionally active, open state, we developed a model in vitro system containing a single, unique, "target" nucleosome in the center of a 25-nucleosome array and evaluated the accessibility of the linker DNA adjacent to this target nucleosome. We found that condensation of H1-lacking chromatin results in ∼60-fold reduction in linker DNA accessibility and that mimics of acetylation within all four core histone tail domains of the target nucleosome synergize to increase accessibility ∼3-fold. Notably, stoichiometric binding of histone H1 caused >2 orders of magnitude reduction in accessibility that was marginally diminished by histone acetylation mimics. Remarkably, a nucleosome-free region (NFR) in place of the target nucleosome completely abrogated H1-dependent restriction of linker accessibility in the immediate vicinity of the NFR. Our results suggest that linker DNA is as inaccessible as DNA within the nucleosome core in fully condensed, H1-containing chromatin. They further imply that an unrecognized function of NFRs in gene promoter regions is to locally abrogate the severe restriction of linker DNA accessibility imposed by H1s.
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Affiliation(s)
- Laxmi Narayan Mishra
- From the Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642
| | - Jeffrey J Hayes
- From the Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642
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9
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Menoni H, Di Mascio P, Cadet J, Dimitrov S, Angelov D. Chromatin associated mechanisms in base excision repair - nucleosome remodeling and DNA transcription, two key players. Free Radic Biol Med 2017; 107:159-169. [PMID: 28011149 DOI: 10.1016/j.freeradbiomed.2016.12.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/13/2016] [Accepted: 12/19/2016] [Indexed: 12/30/2022]
Abstract
Genomic DNA is prone to a large number of insults by a myriad of endogenous and exogenous agents. The base excision repair (BER) is the major mechanism used by cells for the removal of various DNA lesions spontaneously or environmentally induced and the maintenance of genome integrity. The presence of persistent DNA damage is not compatible with life, since abrogation of BER leads to early embryonic lethality in mice. There are several lines of evidences showing existence of a link between deficient BER, cancer proneness and ageing, thus illustrating the importance of this DNA repair pathway in human health. Although the enzymology of BER mechanisms has been largely elucidated using chemically defined DNA damage substrates and purified proteins, the complex interplay of BER with another vital process like transcription or when DNA is in its natural state (i.e. wrapped in nucleosome and assembled in chromatin fiber is largely unexplored. Cells use chromatin remodeling factors to overcome the general repression associated with the nucleosomal organization. It is broadly accepted that energy-dependent nucleosome remodeling factors disrupt histones-DNA interactions at the expense of ATP hydrolysis to favor transcription as well as DNA repair. Importantly, unlike transcription, BER is not part of a regulated developmental process but represents a maintenance system that should be efficient anytime and anywhere in the genome. In this review we will discuss how BER can deal with chromatin organization to maintain genetic information. Emphasis will be placed on the following challenging question: how BER is initiated within chromatin?
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Affiliation(s)
- Hervé Menoni
- Laboratoire de Biologie et Modélisation de la Cellule (LBMC) CNRS/ENSL/UCBL UMR 5239 and Institut NeuroMyoGène - INMG CNRS/UCBL UMR 5310, Université de Lyon, Ecole Normale Supérieure de Lyon, 69007 Lyon, France; Université de Grenoble Alpes/INSERM U1209/CNRS UMR 5309, 38042 Grenoble Cedex 9, France.
| | - Paolo Di Mascio
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05508-000 São Paulo, SP, Brazil
| | - Jean Cadet
- Département de Médecine Nucléaire et de Radiobiologie, Université de Sherbrooke, Sherbrooke, Québec, Canada J1H 5N4
| | - Stefan Dimitrov
- Université de Grenoble Alpes/INSERM U1209/CNRS UMR 5309, 38042 Grenoble Cedex 9, France
| | - Dimitar Angelov
- Laboratoire de Biologie et Modélisation de la Cellule (LBMC) CNRS/ENSL/UCBL UMR 5239 and Institut NeuroMyoGène - INMG CNRS/UCBL UMR 5310, Université de Lyon, Ecole Normale Supérieure de Lyon, 69007 Lyon, France.
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10
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BPTF is required for c-MYC transcriptional activity and in vivo tumorigenesis. Nat Commun 2016; 7:10153. [PMID: 26729287 PMCID: PMC4728380 DOI: 10.1038/ncomms10153] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 11/06/2015] [Indexed: 01/06/2023] Open
Abstract
c-MYC oncogene is deregulated in most human tumours. Histone marks associated with transcriptionally active genes define high-affinity c-MYC targets. The mechanisms involved in their recognition by c-MYC are unknown. Here we report that c-MYC interacts with BPTF, a core subunit of the NURF chromatin-remodelling complex. BPTF is required for the activation of the full c-MYC transcriptional programme in fibroblasts. BPTF knockdown leads to decreased c-MYC recruitment to DNA and changes in chromatin accessibility. In Bptf-null MEFs, BPTF is necessary for c-MYC-driven proliferation, G1–S progression and replication stress, but not for c-MYC-driven apoptosis. Bioinformatics analyses unveil that BPTF levels correlate positively with c-MYC-driven transcriptional signatures. In vivo, Bptf inactivation in pre-neoplastic pancreatic acinar cells significantly delays tumour development and extends survival. Our findings uncover BPTF as a crucial c-MYC co-factor required for its biological activity and suggest that the BPTF-c-MYC axis is a potential therapeutic target in cancer. c-MYC genomic distribution is dictated by the epigenetic context but the mechanisms are unknown. Here, the authors show that c-MYC requires the chromatin reader BPTF to activate its transcriptional program and promote tumour development in vivo, suggesting that BPTF is a potential target for cancer therapy.
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11
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Functional interplay between histone H1 and HMG proteins in chromatin. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2015; 1859:462-7. [PMID: 26455954 DOI: 10.1016/j.bbagrm.2015.10.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 10/02/2015] [Accepted: 10/05/2015] [Indexed: 11/22/2022]
Abstract
The dynamic interaction of nucleosome binding proteins with their chromatin targets is an important element in regulating the structure and function of chromatin. Histone H1 variants and High Mobility Group (HMG) proteins are ubiquitously expressed in all vertebrate cells, bind dynamically to chromatin, and are known to affect chromatin condensation and the ability of regulatory factors to access their genomic binding sites. Here, we review the studies that focus on the interactions between H1 and HMGs and highlight the functional consequences of the interplay between these architectural chromatin binding proteins. H1 and HMG proteins are mobile molecules that bind to nucleosomes as members of a dynamic protein network. All HMGs compete with H1 for chromatin binding sites, in a dose dependent fashion, but each HMG family has specific effects on the interaction of H1 with chromatin. The interplay between H1 and HMGs affects chromatin organization and plays a role in epigenetic regulation.
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12
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Flanagan TW, Brown DT. Molecular dynamics of histone H1. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2015; 1859:468-75. [PMID: 26454113 DOI: 10.1016/j.bbagrm.2015.10.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 09/17/2015] [Accepted: 10/05/2015] [Indexed: 12/28/2022]
Abstract
The H1 or linker histones bind dynamically to chromatin in living cells via a process that involves transient association with the nucleosome near the DNA entry/exit site followed by dissociation, translocation to a new location, and rebinding. The mean residency time of H1 on any given nucleosome is about a minute, which is much shorter than that of most core histones but considerably longer than that of most other chromatin-binding proteins, including transcription factors. Here we review recent advances in understanding the kinetic pathway of H1 binding and how it relates to linker histone structure and function. We also describe potential mechanisms by which the dynamic binding of H1 might contribute directly to the regulation of gene expression and discuss several situations for which there is experimental evidence to support these mechanisms. Finally, we review the evidence for the participation of linker histone chaperones in mediating H1 exchange.
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Affiliation(s)
- Thomas W Flanagan
- Department of Biochemistry, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA
| | - David T Brown
- Department of Biochemistry, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
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13
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Georgieva M, Staneva D, Uzunova K, Efremov T, Balashev K, Harata M, Miloshev G. The linker histone in Saccharomyces cerevisiae interacts with actin-related protein 4 and both regulate chromatin structure and cellular morphology. Int J Biochem Cell Biol 2015; 59:182-92. [DOI: 10.1016/j.biocel.2014.12.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 12/15/2014] [Indexed: 11/28/2022]
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14
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Medrzycki M, Zhang Y, Zhang W, Cao K, Pan C, Lailler N, McDonald JF, Bouhassira EE, Fan Y. Histone h1.3 suppresses h19 noncoding RNA expression and cell growth of ovarian cancer cells. Cancer Res 2014; 74:6463-73. [PMID: 25205099 DOI: 10.1158/0008-5472.can-13-2922] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Ovarian cancer is a deadly gynecologic malignancy for which novel biomarkers and therapeutic targets are imperative for improving survival. Previous studies have suggested the expression pattern of linker histone variants as potential biomarkers for ovarian cancer. To investigate the role of histone H1 in ovarian cancer cells, we characterize individual H1 variants and overexpress one of the major somatic H1 variants, H1.3, in the OVCAR-3 epithelial ovarian cancer cell line. We find that overexpression of H1.3 decreases the growth rate and colony formation of OVCAR-3 cells. We identify histone H1.3 as a specific repressor for the noncoding oncogene H19. Overexpression of H1.3 suppresses H19 expression, and knockdown of H1.3 increases its expression in multiple ovarian epithelial cancer cell lines. Furthermore, we demonstrate that histone H1.3 overexpression leads to increased occupancy of H1.3 at the H19 regulator region encompassing the imprinting control region (ICR), concomitant with increased DNA methylation and reduced occupancy of the insulator protein CTCF at the ICR. Finally, we demonstrate that H1.3 overexpression and H19 knockdown synergistically decrease the growth rate of ovarian cancer cells. Our findings suggest that H1.3 dramatically inhibits H19 expression, which contributes to the suppression of epithelial ovarian carcinogenesis.
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Affiliation(s)
- Magdalena Medrzycki
- School of Biology, Georgia Institute of Technology, Atlanta, Georgia. The Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia
| | - Yunzhe Zhang
- School of Biology, Georgia Institute of Technology, Atlanta, Georgia. The Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia
| | - Weijia Zhang
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York
| | - Kaixiang Cao
- School of Biology, Georgia Institute of Technology, Atlanta, Georgia. The Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia
| | - Chenyi Pan
- School of Biology, Georgia Institute of Technology, Atlanta, Georgia. The Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia
| | | | - John F McDonald
- School of Biology, Georgia Institute of Technology, Atlanta, Georgia. The Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia
| | - Eric E Bouhassira
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York
| | - Yuhong Fan
- School of Biology, Georgia Institute of Technology, Atlanta, Georgia. The Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia.
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15
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Cannan WJ, Tsang BP, Wallace SS, Pederson DS. Nucleosomes suppress the formation of double-strand DNA breaks during attempted base excision repair of clustered oxidative damages. J Biol Chem 2014; 289:19881-93. [PMID: 24891506 DOI: 10.1074/jbc.m114.571588] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Exposure to ionizing radiation can produce multiple, clustered oxidative lesions in DNA. The near simultaneous excision of nearby lesions in opposing DNA strands by the base excision repair (BER) enzymes can produce double-strand DNA breaks (DSBs). This attempted BER accounts for many of the potentially lethal or mutagenic DSBs that occur in vivo. To assess the impact of nucleosomes on the frequency and pattern of BER-dependent DSB formation, we incubated nucleosomes containing oxidative damages in opposing DNA strands with selected DNA glycosylases and human apurinic/apyrimidinic endonuclease 1. Overall, nucleosomes substantially suppressed DSB formation. However, the degree of suppression varied as a function of (i) the lesion type and DNA glycosylase tested, (ii) local sequence context and the stagger between opposing strand lesions, (iii) the helical orientation of oxidative lesions relative to the underlying histone octamer, and (iv) the distance between the lesion cluster and the nucleosome edge. In some instances the binding of a BER factor to one nucleosomal lesion appeared to facilitate binding to the opposing strand lesion. DSB formation did not invariably lead to nucleosome dissolution, and in some cases, free DNA ends resulting from DSB formation remained associated with the histone octamer. These observations explain how specific structural and dynamic properties of nucleosomes contribute to the suppression of BER-generated DSBs. These studies also suggest that most BER-generated DSBs will occur in linker DNA and in genomic regions associated with elevated rates of nucleosome turnover or remodeling.
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Affiliation(s)
- Wendy J Cannan
- From the Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405
| | - Betty P Tsang
- From the Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405
| | - Susan S Wallace
- From the Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405
| | - David S Pederson
- From the Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405
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16
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Kadota S, Nagata K. Silencing of IFN-stimulated gene transcription is regulated by histone H1 and its chaperone TAF-I. Nucleic Acids Res 2014; 42:7642-53. [PMID: 24878923 PMCID: PMC4081089 DOI: 10.1093/nar/gku485] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Chromatin structure and its alteration play critical roles in the regulation of transcription. However, the transcriptional silencing mechanism with regard to the chromatin structure at an unstimulated state of the interferon (IFN)-stimulated gene (ISG) remains unclear. Here we investigated the role of template activating factor-I (TAF-I, also known as SET) in ISG transcription. Knockdown (KD) of TAF-I increased ISG transcript and simultaneously reduced the histone H1 level on the ISG promoters during the early stages of transcription after IFN stimulation from the unstimulated state. The transcription factor levels on the ISG promoters were increased in TAF-I KD cells only during the early stages of transcription. Furthermore, histone H1 KD also increased ISG transcript. TAF-I and histone H1 double KD did not show the additive effect in ISG transcription, suggesting that TAF-I and histone H1 may act on the same regulatory pathway to control ISG transcription. In addition, TAF-I KD and histone H1 KD affected the chromatin structure near the ISG promoters. On the basis of these findings, we propose that TAF-I and its target histone H1 are key regulators of the chromatin structure at the ISG promoter to maintain the silent state of ISG transcription.
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Affiliation(s)
- Shinichi Kadota
- Department of Infection Biology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
| | - Kyosuke Nagata
- Department of Infection Biology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
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17
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Harshman SW, Young NL, Parthun MR, Freitas MA. H1 histones: current perspectives and challenges. Nucleic Acids Res 2013; 41:9593-609. [PMID: 23945933 PMCID: PMC3834806 DOI: 10.1093/nar/gkt700] [Citation(s) in RCA: 168] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
H1 and related linker histones are important both for maintenance of higher-order chromatin structure and for the regulation of gene expression. The biology of the linker histones is complex, as they are evolutionarily variable, exist in multiple isoforms and undergo a large variety of posttranslational modifications in their long, unstructured, NH2- and COOH-terminal tails. We review recent progress in understanding the structure, genetics and posttranslational modifications of linker histones, with an emphasis on the dynamic interactions of these proteins with DNA and transcriptional regulators. We also discuss various experimental challenges to the study of H1 and related proteins, including limitations of immunological reagents and practical difficulties in the analysis of posttranslational modifications by mass spectrometry.
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Affiliation(s)
- Sean W Harshman
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, Ohio, USA, College of Medicine and Arthur G. James Comprehensive Cancer Center, Columbus, Ohio, USA, National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, USA and Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio, USA
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18
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Menoni H, Shukla MS, Gerson V, Dimitrov S, Angelov D. Base excision repair of 8-oxoG in dinucleosomes. Nucleic Acids Res 2011; 40:692-700. [PMID: 21930508 PMCID: PMC3258150 DOI: 10.1093/nar/gkr761] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
In this work we have studied the effect of chromatin structure on the base excision repair (BER) efficiency of 8-oxoG. As a model system we have used precisely positioned dinucleosomes assembled with linker histone H1. A single 8-oxoG was inserted either in the linker or the core particle DNA within the dinucleosomal template. We found that in the absence of histone H1 the glycosylase OGG1 removed 8-oxoG from the linker DNA and cleaved DNA with identical efficiency as in the naked DNA. In contrast, the presence of histone H1 resulted in close to 10-fold decrease in the efficiency of 8-oxoG initiation of repair in linker DNA independently of linker DNA length. The repair of 8-oxoG in nucleosomal DNA was very highly impeded in both absence and presence of histone H1. Chaperone-induced uptake of H1 restored the efficiency of the glycosylase induced removal of 8-oxoG from linker DNA, but not from the nucleosomal DNA. We show, however, that removal of histone H1 and nucleosome remodelling are both necessary and sufficient for an efficient removal of 8-oxoG in nucleosomal DNA. Finally, a model for BER of 8-oxoG in chromatin templates is suggested.
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Affiliation(s)
- Hervé Menoni
- Université de Lyon, Laboratoire de Biologie Moléculaire de la Cellule, CNRS-UMR 5239, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon cedex 07, France
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19
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Chrysanthou-Piterou M, Havaki S, Alevizos V, Papadimitriou GN, Issidorides MR. Chromatin ultrastructural abnormalities in leukocytes, as peripheral markers of bipolar patients. Ultrastruct Pathol 2010; 33:197-208. [PMID: 19895292 DOI: 10.3109/01913120903288579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
This study investigated the ultrastructural conformation changes of the chromatin in blood leukocytes of bipolar patients, versus normal controls, by using the phosphotungstic acid-hematoxylin (PTAH) block-staining method, modified for electron microscopy, and the immunohistochemical localization of the histone H1, by the immunogold method. These two methods are basically complementary. If histone H1 immunolabeling is used, it shows that the immunogold labeling on chromatin is different in the three phases of the illness, i.e., high in normothymia and low in depression as well as in mania. However, in this particular tissue fixation (4% paraformaldehyde-1% glutaraldehyde in 0,1 M phosphate buffer), the heterochromatin in the nuclei remains identical in the three phases of the illness. On the other hand, the PTAH method shows exactly the area of electron-lucent condensed chromatin, separate from the area of electron-dense, decondensed, chromatin. The present data confirmed that both the clinical state of depression as well as that of mania display activated lymphocytes and neutrophils with their characteristic relaxed de-condensed chromatin. On the contrary, the state of normothymia shows a reversion to the condensed state of the chromatin, as it is observed in the leukocytes of the normal controls. The ultrastructural conformations of the chromatin, revealed by the PTAH method, in combination with the histone H1 immunogold labeling, applied in blood leukocytes, supports the use of these two methods, as screening methods of choice in investigating blood biological markers in mental illness.
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20
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Histone H1 subtypes differentially modulate chromatin condensation without preventing ATP-dependent remodeling by SWI/SNF or NURF. PLoS One 2009; 4:e0007243. [PMID: 19794910 PMCID: PMC2748705 DOI: 10.1371/journal.pone.0007243] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Accepted: 09/07/2009] [Indexed: 12/16/2022] Open
Abstract
Although ubiquitously present in chromatin, the function of the linker histone subtypes is partly unknown and contradictory studies on their properties have been published. To explore whether the various H1 subtypes have a differential role in the organization and dynamics of chromatin we have incorporated all of the somatic human H1 subtypes into minichromosomes and compared their influence on nucleosome spacing, chromatin compaction and ATP-dependent remodeling. H1 subtypes exhibit different affinities for chromatin and different abilities to promote chromatin condensation, as studied with the Atomic Force Microscope. According to this criterion, H1 subtypes can be classified as weak condensers (H1.1 and H1.2), intermediate condensers (H1.3) and strong condensers (H1.0, H1.4, H1.5 and H1x). The variable C-terminal domain is required for nucleosome spacing by H1.4 and is likely responsible for the chromatin condensation properties of the various subtypes, as shown using chimeras between H1.4 and H1.2. In contrast to previous reports with isolated nucleosomes or linear nucleosomal arrays, linker histones at a ratio of one per nucleosome do not preclude remodeling of minichromosomes by yeast SWI/SNF or Drosophila NURF. We hypothesize that the linker histone subtypes are differential organizers of chromatin, rather than general repressors.
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21
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Abstract
The packaging of chromosomal DNA by nucleosomes condenses and organizes the genome, but occludes many regulatory DNA elements. However, this constraint also allows nucleosomes and other chromatin components to actively participate in the regulation of transcription, chromosome segregation, DNA replication, and DNA repair. To enable dynamic access to packaged DNA and to tailor nucleosome composition in chromosomal regions, cells have evolved a set of specialized chromatin remodeling complexes (remodelers). Remodelers use the energy of ATP hydrolysis to move, destabilize, eject, or restructure nucleosomes. Here, we address many aspects of remodeler biology: their targeting, mechanism, regulation, shared and unique properties, and specialization for particular biological processes. We also address roles for remodelers in development, cancer, and human syndromes.
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Affiliation(s)
- Cedric R Clapier
- Howard Hughes Medical Institute, Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, UT 84112, USA.
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22
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Rattner BP, Yusufzai T, Kadonaga JT. HMGN proteins act in opposition to ATP-dependent chromatin remodeling factors to restrict nucleosome mobility. Mol Cell 2009; 34:620-6. [PMID: 19524541 DOI: 10.1016/j.molcel.2009.04.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 04/03/2009] [Accepted: 04/10/2009] [Indexed: 12/20/2022]
Abstract
The high-mobility group N (HMGN) proteins are abundant nonhistone chromosomal proteins that bind specifically to nucleosomes at two high-affinity sites. Here we report that purified recombinant human HMGN1 (HMG14) and HMGN2 (HMG17) potently repress ATP-dependent chromatin remodeling by four different molecular motor proteins. In contrast, mutant HMGN proteins with double Ser-to-Glu mutations in their nucleosome-binding domains are unable to inhibit chromatin remodeling. The HMGN-mediated repression of chromatin remodeling is reversible and dynamic. With the ACF chromatin remodeling factor, HMGN2 does not directly inhibit the ATPase activity but rather appears to reduce the affinity of the factor to chromatin. These findings suggest that HMGN proteins serve as a counterbalance to the action of the many ATP-dependent chromatin remodeling activities in the nucleus.
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Affiliation(s)
- Barbara P Rattner
- Section of Molecular Biology, University of California, San Diego, La Jolla, CA 92093-0347, USA
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23
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Raghuram N, Carrero G, Th’ng J, Hendzel MJ. Molecular dynamics of histone H1This paper is one of a selection of papers published in this Special Issue, entitled CSBMCB’s 51st Annual Meeting – Epigenetics and Chromatin Dynamics, and has undergone the Journal’s usual peer review process. Biochem Cell Biol 2009; 87:189-206. [DOI: 10.1139/o08-127] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The histone H1 family of nucleoproteins represents an important class of structural and architectural proteins that are responsible for maintaining and stabilizing higher-order chromatin structure. Essential for mammalian cell viability, they are responsible for gene-specific regulation of transcription and other DNA-dependent processes. In this review, we focus on the wealth of information gathered on the molecular kinetics of histone H1 molecules using novel imaging techniques, such as fluorescence recovery after photobleaching. These experiments have shed light on the effects of H1 phosphorylation and core histone acetylation in influencing chromatin structure and dynamics. We also delineate important concepts surrounding the C-terminal domain of H1, such as the intrinsic disorder hypothesis, and how it affects H1 function. Finally, we address the biochemical mechanisms behind low-affinity H1 binding.
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Affiliation(s)
- Nikhil Raghuram
- Department of Oncology, University of Alberta, University Avenue NW, Edmonton, AB T6G 1Z2, Canada
- Mathematics, Center for Science, Athabasca University, Edmonton, AB T5J 3S8, Canada
- Regional Cancer Centre, Medical Science Division, Northern Ontario School of Medicine, Thunder Bay Regional Health Sciences Centre, Thunder Bay, ON P7B 6V4, Canada
| | - Gustavo Carrero
- Department of Oncology, University of Alberta, University Avenue NW, Edmonton, AB T6G 1Z2, Canada
- Mathematics, Center for Science, Athabasca University, Edmonton, AB T5J 3S8, Canada
- Regional Cancer Centre, Medical Science Division, Northern Ontario School of Medicine, Thunder Bay Regional Health Sciences Centre, Thunder Bay, ON P7B 6V4, Canada
| | - John Th’ng
- Department of Oncology, University of Alberta, University Avenue NW, Edmonton, AB T6G 1Z2, Canada
- Mathematics, Center for Science, Athabasca University, Edmonton, AB T5J 3S8, Canada
- Regional Cancer Centre, Medical Science Division, Northern Ontario School of Medicine, Thunder Bay Regional Health Sciences Centre, Thunder Bay, ON P7B 6V4, Canada
| | - Michael J. Hendzel
- Department of Oncology, University of Alberta, University Avenue NW, Edmonton, AB T6G 1Z2, Canada
- Mathematics, Center for Science, Athabasca University, Edmonton, AB T5J 3S8, Canada
- Regional Cancer Centre, Medical Science Division, Northern Ontario School of Medicine, Thunder Bay Regional Health Sciences Centre, Thunder Bay, ON P7B 6V4, Canada
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24
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Takeshima H, Suetake I, Tajima S. Mouse Dnmt3a Preferentially Methylates Linker DNA and Is Inhibited by Histone H1. J Mol Biol 2008; 383:810-21. [DOI: 10.1016/j.jmb.2008.03.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Revised: 02/06/2008] [Accepted: 03/02/2008] [Indexed: 11/24/2022]
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25
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Abstract
Chromatin serves to package, protect and organize the complex eukaryotic genomes to assure their stable inheritance over many cell generations. At the same time, chromatin must be dynamic to allow continued use of DNA during a cell's lifetime. One important principle that endows chromatin with flexibility involves ATP-dependent 'remodeling' factors, which alter DNA-histone interactions to form, disrupt or move nucleosomes. Remodeling is well documented at the nucleosomal level, but little is known about the action of remodeling factors in a more physiological chromatin environment. Recent findings suggest that some remodeling machines can reorganize even folded chromatin fibers containing the linker histone H1, extending the potential scope of remodeling reactions to the bulk of euchromatin.
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Affiliation(s)
- Verena K Maier
- Adolf-Butenandt Institut, Abt. Molekularbiologie, and Münchner Zentrum für Integrierte Proteinforschung, Ludwig-Maximilian-Universität München, Schillerstrasse 44, D-80336 München, Germany
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26
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Deterding LJ, Bunger MK, Banks GC, Tomer KB, Archer TK. Global changes in and characterization of specific sites of phosphorylation in mouse and human histone H1 Isoforms upon CDK inhibitor treatment using mass spectrometry. J Proteome Res 2008; 7:2368-79. [PMID: 18416567 DOI: 10.1021/pr700790a] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Global changes in the phosphorylation state of human H1 isoforms isolated from UL3 cells have been investigated using mass spectrometry. Relative changes in H1 phosphorylation between untreated cells and cells treated with dexamethasone or various CDK inhibitors were determined. The specific cyclin-dependent kinase consensus sites of phosphorylation on the histone H1 isoforms that show changes in phosphorylation were also investigated. Three sites of phosphorylation on histone H1.4 isoforms have been identified.
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Affiliation(s)
- Leesa J Deterding
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, DHHS, P.O. Box 12233, RTP, North Carolina 27709, USA.
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27
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Belova GI, Postnikov YV, Furusawa T, Birger Y, Bustin M. Chromosomal protein HMGN1 enhances the heat shock-induced remodeling of Hsp70 chromatin. J Biol Chem 2008; 283:8080-8. [PMID: 18218636 DOI: 10.1074/jbc.m709782200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The nucleosome-binding protein HMGN1 affects the structure and function of chromatin; however, its role in regulating specific gene expression in living cells is not fully understood. Here we use embryonic fibroblasts from Hmgn1(+/+) and Hmgn1(-/-) mice to examine the effect of HMGN1 on the heat shock-induced transcriptional activation of Hsp70, a well characterized gene known to undergo a rapid chromatin re-structuring during transcriptional activation. We find that loss of HMGN1 decreases the levels of Hsp70 transcripts at the early stages of heat shock. HMGN1 enhances the rate of heat shockinduced changes in the Hsp70 chromatin but does not affect the chromatin structure before induction, an indication that it does not predispose the gene to rapid activation. Heat shock elevates the levels of H3K14 acetylation in the Hsp70 chromatin of wild type cells more efficiently than in the chromatin of Hmgn1(-/-) cells, whereas treatment with histone deacetylase inhibitors abrogates the effects of HMGN1 on the heat shock response. We suggest that HMGN1 enhances the rate of heat shock-induced H3K14 acetylation in the Hsp70 promoter, thereby enhancing the rate of chromatin remodeling and the subsequent transcription during the early rounds of Hsp70 activation when the gene is still associated with histones in a nucleosomal conformation.
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Affiliation(s)
- Galina I Belova
- Protein Section, Laboratory of Metabolism, NCI, NIH, Bethesda, MD 20892, USA
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28
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Maier VK, Chioda M, Rhodes D, Becker PB. ACF catalyses chromatosome movements in chromatin fibres. EMBO J 2007; 27:817-26. [PMID: 17962805 DOI: 10.1038/sj.emboj.7601902] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2007] [Accepted: 10/04/2007] [Indexed: 12/18/2022] Open
Abstract
Nucleosome-remodelling factors containing the ATPase ISWI, such as ACF, render DNA in chromatin accessible by promoting the sliding of histone octamers. Although the ATP-dependent repositioning of mononucleosomes is readily observable in vitro, it is unclear to which extent nucleosomes can be moved in physiological chromatin, where neighbouring nucleosomes, linker histones and the folding of the nucleosomal array restrict mobility. We assembled arrays consisting of 12 nucleosomes or 12 chromatosomes (nucleosomes plus linker histone) from defined components and subjected them to remodelling by ACF or the ATPase CHD1. Both factors increased the access to DNA in nucleosome arrays. ACF, but not CHD1, catalysed profound movements of nucleosomes throughout the array, suggesting different remodelling mechanisms. Linker histones inhibited remodelling by CHD1. Surprisingly, ACF catalysed significant repositioning of entire chromatosomes in chromatin containing saturating levels of linker histone H1. H1 inhibited the ATP-dependent generation of DNA accessibility by only about 50%. This first demonstration of catalysed chromatosome movements suggests that the bulk of interphase euchromatin may be rendered dynamic by dedicated nucleosome-remodelling factors.
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Affiliation(s)
- Verena K Maier
- Molekularbiologie, Adolf-Butenandt Institut, Ludwig Maximilian Universität, Munich, Germany
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29
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Downs JA, Nussenzweig MC, Nussenzweig A. Chromatin dynamics and the preservation of genetic information. Nature 2007; 447:951-8. [PMID: 17581578 DOI: 10.1038/nature05980] [Citation(s) in RCA: 229] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The integrity of the genome is frequently challenged by double-strand breaks in the DNA. Defects in the cellular response to double-strand breaks are a major cause of cancer and other age-related pathologies; therefore, much effort has been directed at understanding the enzymatic mechanisms involved in recognizing, signalling and repairing double-strand breaks. Recent work indicates that chromatin - the fibres into which DNA is packaged with a proteinaceous structural polymer - has an important role in initiating, propagating and terminating this cellular response to DNA damage.
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Affiliation(s)
- Jessica A Downs
- MRC Genome Damage and Stability Centre, University of Sussex, Brighton BN1 9RQ, UK.
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30
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Gutiérrez J, Paredes R, Cruzat F, Hill DA, van Wijnen AJ, Lian JB, Stein GS, Stein JL, Imbalzano AN, Montecino M. Chromatin Remodeling by SWI/SNF Results in Nucleosome Mobilization to Preferential Positions in the Rat Osteocalcin Gene Promoter. J Biol Chem 2007; 282:9445-9457. [PMID: 17272279 DOI: 10.1074/jbc.m609847200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Changes in local chromatin structure accompany transcriptional activation of eukaryotic genes. In vivo these changes in chromatin organization can be catalyzed by ATP-dependent chromatin-remodeling complexes, such as SWI/SNF. These complexes alter the tight wrapping of DNA in the nucleosomes and can facilitate the mobilization of the histone octamer to adjacent DNA segments, leaving promoter regulatory elements exposed for transcription factor binding. To gain understanding of how the activity of SWI/SNF complexes may be modulated by the different DNA sequences within a natural promoter, we have reconstituted nucleosomes containing promoter segments of the transcriptionally active cell type-specific osteocalcin (OC) gene and determined how they affect the directional movements of the nucleosomes. Our results indicate that SWI/SNF complexes induce octamer sliding to preferential positions in the OC promoter, leading to a nucleosomal organization that resembles that described in intact cells expressing the OC gene. Our studies demonstrate that the position of the histone octamer is primarily determined by sequences within the OC promoter that include or exclude nucleosomes. We propose that these sequences are critical components of the regulatory mechanisms that mediate expression of this tissue-specific gene.
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Affiliation(s)
- José Gutiérrez
- Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Biologicas, Universidad de Concepcion, Barrio Universitario s/n, Casilla 160-C, Concepcion 4079100, Chile
| | - Roberto Paredes
- Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Biologicas, Universidad de Concepcion, Barrio Universitario s/n, Casilla 160-C, Concepcion 4079100, Chile
| | - Fernando Cruzat
- Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Biologicas, Universidad de Concepcion, Barrio Universitario s/n, Casilla 160-C, Concepcion 4079100, Chile
| | - David A Hill
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Andre J van Wijnen
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Jane B Lian
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Gary S Stein
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Janet L Stein
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Anthony N Imbalzano
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Martin Montecino
- Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Biologicas, Universidad de Concepcion, Barrio Universitario s/n, Casilla 160-C, Concepcion 4079100, Chile.
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31
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Yang Z, Zheng C, Hayes JJ. The Core Histone Tail Domains Contribute to Sequence-dependent Nucleosome Positioning. J Biol Chem 2007; 282:7930-8. [PMID: 17234628 DOI: 10.1074/jbc.m610584200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The precise positioning of nucleosomes plays a critical role in the regulation of gene expression by modulating the DNA binding activity of trans-acting factors. However, molecular determinants responsible for positioning are not well understood. We examined whether the removal of the core histone tail domains from nucleosomes reconstituted with specific DNA fragments led to alteration of translational positions. Remarkably, we find that removal of tail domains from a nucleosome assembled on a DNA fragment containing a Xenopus borealis somatic-type 5S RNA gene results in repositioning of nucleosomes along the DNA, including two related major translational positions that move about 20 bp further upstream with respect to the 5S gene. In a nucleosome reconstituted with a DNA fragment containing the promoter of a Drosophila alcohol dehydrogenase gene, several translational positions shifted by about 10 bp along the DNA upon tail removal. However, the positions of nucleosomes assembled with a DNA fragment known to have one of the highest binding affinities for core histone proteins in the mouse genome were not altered by removal of core histone tail domains. Our data support the notion that the basic tail domains bind to nucleosomal DNA and influence the selection of the translational position of nucleosomes and that once tails are removed movement between translational positions occurs in a facile manner on some sequences. However, the effect of the N-terminal tails on the positioning and movement of a nucleosome appears to be dependent on the DNA sequence such that the contribution of the tails can be masked by very high affinity DNA sequences. Our results suggest a mechanism whereby sequence-dependent nucleosome positioning can be specifically altered by regulated changes in histone tail-DNA interactions in chromatin.
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Affiliation(s)
- Zungyoon Yang
- Department of Biochemistry and Biophysics, University of Rochester, Rochester, New York 14642, USA
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32
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Hogan C, Varga-Weisz P. The regulation of ATP-dependent nucleosome remodelling factors. Mutat Res 2007; 618:41-51. [PMID: 17306842 DOI: 10.1016/j.mrfmmm.2006.07.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Accepted: 07/18/2006] [Indexed: 11/17/2022]
Abstract
The plasticity of chromatin is governed by multi-subunit protein complexes that enzymatically regulate chromosomal structure and activity. Such complexes include ATP-dependent chromatin remodelling factors that are involved in many fundamental processes such as transcription, DNA repair, replication and chromosome structure maintenance. Because ATP-dependent chromatin remodelling factors play important roles, it is not surprising to find that their functions are regulated in a plethora of ways, including post-translational modifications of their subunits and subunit composition changes. The activity of these enzymes is modulated by many factors, including linker histones, histone variants, histone chaperones, non-histone chromatin constituents such as HMG-proteins and secondary messengers, such as inositolpolyphosphates. Additionally, specific histone modifications and interaction with site-specific transcriptional regulators direct the targeting of these activities. Understanding the network of mechanisms that control ATP-dependent chromatin remodelling will constitute an important challenge towards our understanding of chromatin dynamics.
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33
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Song X, Gorovsky MA. Unphosphorylated H1 is enriched in a specific region of the promoter when CDC2 is down-regulated during starvation. Mol Cell Biol 2006; 27:1925-33. [PMID: 17194754 PMCID: PMC1820472 DOI: 10.1128/mcb.01619-06] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Tetrahymena thermophila macronuclear histone H1 is phosphorylated by a cdc2 kinase, and H1 phosphorylation regulates CDC2 expression by a positive feedback mechanism. In starved wild-type cells, decreased expression of the CDC2 gene is correlated with a global reduction in the phosphorylation of H1 and reduced phosphorylation of H1 in the region upstream of the CDC2 gene. To determine whether the reduced H1 phosphorylation upstream of the CDC2 gene is merely a reflection of global dephosphorylation or is due to specific targeting of dephosphorylation of H1 to the CDC2 promoter during starvation, the CDC2 promoter was mapped, and the distributions of phosphorylated and unphosphorylated H1 across the CDC2 gene were determined using chromatin immunoprecipitation. Unphosphorylated H1 is specifically enriched in a region of the CDC2 promoter when the gene's expression is reduced during starvation but not when CDC2 is highly active in growing cells. The region of unphosphorylated H1 coincides with a region that is essential for CDC2 expression. These studies are the first in vivo demonstration that the phosphorylation of H1 is being regulated at a fine level and that unphosphorylated H1 can be specifically targeted to a promoter, where it likely regulates transcription in a gene-specific manner.
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Affiliation(s)
- Xiaoyuan Song
- Department of Biology, University of Rochester, Rochester, NY 14627, USA.
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34
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Abstract
It is now widely recognized that the packaging of genomic DNA together with core histones, linker histones, and other functional proteins into chromatin profoundly influences nuclear processes such as transcription, replication, repair and recombination. How chromatin structure modulates the expression and maintenance of knowledge encoded in eukaryotic genomes, and how these processes take place within the context of a highly complex and compacted genomic chromatin environment remains a major unresolved question in biology. Here we review recent advances in our understanding of how nucleosome and chromatin structure may have to adapt to promote these vital functions.
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Affiliation(s)
- Karolin Luger
- Howard Hughes Medical Institute and Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, 80523-1870, USA.
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35
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Hartlepp KF, Fernández-Tornero C, Eberharter A, Grüne T, Müller CW, Becker PB. The histone fold subunits of Drosophila CHRAC facilitate nucleosome sliding through dynamic DNA interactions. Mol Cell Biol 2005; 25:9886-96. [PMID: 16260604 PMCID: PMC1280263 DOI: 10.1128/mcb.25.22.9886-9896.2005] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The chromatin accessibility complex (CHRAC) is an abundant, evolutionarily conserved nucleosome remodeling machinery able to catalyze histone octamer sliding on DNA. CHRAC differs from the related ACF complex by the presence of two subunits with molecular masses of 14 and 16 kDa, whose structure and function were not known. We determined the structure of Drosophila melanogaster CHRAC14-CHRAC16 by X-ray crystallography at 2.4-angstroms resolution and found that they dimerize via a variant histone fold in a typical handshake structure. In further analogy to histones, CHRAC14-16 contain unstructured N- and C-terminal tail domains that protrude from the handshake structure. A dimer of CHRAC14-16 can associate with the N terminus of ACF1, thereby completing CHRAC. Low-affinity interactions of CHRAC14-16 with DNA significantly improve the efficiency of nucleosome mobilization by limiting amounts of ACF. Deletion of the negatively charged C terminus of CHRAC16 enhances DNA binding 25-fold but leads to inhibition of nucleosome sliding, in striking analogy to the effect of the DNA chaperone HMGB1 on nucleosome sliding. The presence of a surface compatible with DNA interaction and the geometry of an H2A-H2B heterodimer may provide a transient acceptor site for DNA dislocated from the histone surface and therefore facilitate the nucleosome remodeling process.
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Affiliation(s)
- Klaus F Hartlepp
- European Molecular Biology Laboratory, Grenoble Outstation, France
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36
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Qian C, Zhang Q, Li S, Zeng L, Walsh MJ, Zhou MM. Structure and chromosomal DNA binding of the SWIRM domain. Nat Struct Mol Biol 2005; 12:1078-85. [PMID: 16299514 DOI: 10.1038/nsmb1022] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2005] [Accepted: 09/19/2005] [Indexed: 01/19/2023]
Abstract
The evolutionarily conserved Swi3p, Rsc8p and Moira (SWIRM) domain is found in many chromosomal proteins involved in chromatin modifications or remodeling. Here we report the three-dimensional solution structure of the SWIRM domain from the human transcriptional adaptor ADA2alpha. The structure reveals a five-helix bundle consisting of two helix-turn-helix motifs connected by a central long helix, reminiscent of the histone fold. Using structural and biochemical analyses, we showed that the SWIRM domains of human ADA2alpha and SMARC2 bind to double-stranded and nucleosomal DNA, and we identified amino acid residues required for this function. We demonstrated that the ADA2alpha SWIRM domain is colocalized with lysine-acetylated histone H3 in the cell nucleus and that it potentiates the ACF remodeling activity by enhancing accessibility of nucleosomal linker DNA bound to histone H1. These data suggest a functional role of the SWIRM domain in chromatin remodeling.
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Affiliation(s)
- Chengmin Qian
- Structural Biology Program, Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York University, One Gustave L. Levy Place, New York, New York 10029, USA
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37
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Hill DA, Peterson CL, Imbalzano AN. Effects of HMGN1 on chromatin structure and SWI/SNF-mediated chromatin remodeling. J Biol Chem 2005; 280:41777-83. [PMID: 16253989 DOI: 10.1074/jbc.m509637200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The dynamic modulation of chromatin structure is determined by many factors, including enzymes that modify the core histone proteins, enzymes that remodel the structure of chromatin, and factors that bind to genomic DNA to affect its structure. Previous work indicates that the nucleosome binding family of high mobility group proteins (HMGN) facilitates the formation of a chromatin structure that is more conducive for transcription. SWI/SNF complexes are ATP-dependent chromatin remodeling enzymes that alter nucleosome structure to facilitate the binding of various regulatory proteins to chromatin. Here we examine the structural consequences of reconstituting chromatin with HMGN1 and the resulting effects on hSWI/SNF function. We demonstrate that HMGN1 decreases the sedimentation velocity of nucleosomal arrays in low ionic strength buffers but has little effect on the structure of more highly folded arrays. We further demonstrate that HMGN1 does not affect SWI/SNF-dependent chromatin remodeling on either mononucleosomes or nucleosomal arrays, indicating that SWI/SNF functions independently of HMGN1.
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Affiliation(s)
- David A Hill
- Department of Cell Biology at the University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA.
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38
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Becker PB. The chromatin accessibility complex: chromatin dynamics through nucleosome sliding. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2005; 69:281-7. [PMID: 16117660 DOI: 10.1101/sqb.2004.69.281] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- P B Becker
- Adolf-Butenandt-Institut, Molekularbiologie, Ludwig-Maximilians-Universität, 80336 München, Germany
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39
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Hill DA, Chiosea S, Jamaluddin S, Roy K, Fischer AH, Boyd DD, Nickerson JA, Imbalzano AN. Inducible changes in cell size and attachment area due to expression of a mutant SWI/SNF chromatin remodeling enzyme. J Cell Sci 2005; 117:5847-54. [PMID: 15537831 DOI: 10.1242/jcs.01502] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The SWI/SNF enzymes belong to a family of ATP-dependent chromatin remodeling enzymes that have been functionally implicated in gene regulation, development, differentiation and oncogenesis. BRG1, the catalytic core subunit of some of the SWI/SNF enzymes, can interact with known tumor suppressor proteins and can act as a tumor suppressor itself. We report that cells that inducibly express ATPase-deficient versions of BRG1 increase in cell volume, area of attachment and nuclear size upon expression of the mutant BRG1 protein. Examination of focal adhesions reveals qualitative changes in paxillin distribution but no difference in the actin cytoskeletal structure. Increases in cell size and shape correlate with over-expression of two integrins and the urokinase-type plasminogen activator receptor (uPAR), which is also involved in cell adhesion and is often over-expressed in metastatic cancer cells. These findings demonstrate that gene expression pathways affected by chromatin remodeling enzymes can regulate the physical dimensions of mammalian cell morphology.
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Affiliation(s)
- David A Hill
- Department of Cell Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA
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40
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Martic G, Karetsou Z, Kefala K, Politou AS, Clapier CR, Straub T, Papamarcaki T. Parathymosin affects the binding of linker histone H1 to nucleosomes and remodels chromatin structure. J Biol Chem 2005; 280:16143-50. [PMID: 15716277 DOI: 10.1074/jbc.m410175200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Linker histone H1 is the major factor that stabilizes higher order chromatin structure and modulates the action of chromatin-remodeling enzymes. We have previously shown that parathymosin, an acidic, nuclear protein binds to histone H1 in vitro and in vivo. Confocal laser scanning microscopy reveals a nuclear punctuate staining of the endogenous protein in interphase cells, which is excluded from dense heterochromatic regions. Using an in vitro chromatin reconstitution system under physiological conditions, we show here that parathymosin (ParaT) inhibits the binding of H1 to chromatin in a dose-dependent manner. Consistent with these findings, H1-containing chromatin assembled in the presence of ParaT has reduced nucleosome spacing. These observations suggest that interaction of the two proteins might result in a conformational change of H1. Fluorescence spectroscopy and circular dichroism-based measurements on mixtures of H1 and ParaT confirm this hypothesis. Human sperm nuclei challenged with ParaT become highly decondensed, whereas overexpression of green fluorescent protein- or FLAG-tagged protein in HeLa cells induces global chromatin decondensation and increases the accessibility of chromatin to micrococcal nuclease digestion. Our data suggest a role of parathymosin in the remodeling of higher order chromatin structure through modulation of H1 interaction with nucleosomes and point to its involvement in chromatin-dependent functions.
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Affiliation(s)
- Goran Martic
- Laboratory of Biological Chemistry, Medical School, University of Ioannina, 45110 Ioannina, Greece
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41
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Karetsou Z, Martic G, Tavoulari S, Christoforidis S, Wilm M, Gruss C, Papamarcaki T. Prothymosin alpha associates with the oncoprotein SET and is involved in chromatin decondensation. FEBS Lett 2005; 577:496-500. [PMID: 15556635 DOI: 10.1016/j.febslet.2004.09.091] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2004] [Accepted: 09/23/2004] [Indexed: 11/26/2022]
Abstract
Prothymosin alpha (ProTalpha) is a histone H1-binding protein that interacts with the transcription coactivator CREB-binding protein and potentiates transcription. Based on coimmunoprecipitation and mammalian two-hybrid assays, we show here that ProTalpha forms a complex with the oncoprotein SET. ProTalpha efficiently decondenses human sperm chromatin, while overexpression of GFP-ProTalpha in mammalian cells results in global chromatin decondensation. These results indicate that decondensation of compacted chromatin fibers is an important step in the mechanism of ProTalpha function.
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Affiliation(s)
- Zoe Karetsou
- Laboratory of Biological Chemistry, Medical School, University of Ioannina, 451 10 Ioannina, Greece
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42
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Flaus A, Owen-Hughes T. Mechanisms for ATP-dependent chromatin remodelling: farewell to the tuna-can octamer? Curr Opin Genet Dev 2004; 14:165-73. [PMID: 15196463 DOI: 10.1016/j.gde.2004.01.007] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
ATP-dependent chromatin remodelling enzymes act to alter chromatin structure during gene regulation. Studies of the ATPase motors that drive these enzymes support the notion that they function as ATP-dependent DNA translocases with limited processivity. The action of these enzymes on nucleosomes results in the alteration of nucleosome positioning and structure. Recent studies have shown that ATP-dependent chromatin remodelling can also either remove or exchange histone dimers between nucleosomes. This provides a new means by which the incorporation of histone variants can be directed. Additional observations support roles for ATP-dependent remodelling enzymes throughout the transcription cycle.
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Affiliation(s)
- Andrew Flaus
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
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43
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Abstract
Linker histones have long been known to facilitate chromatin condensation in vitro. For many years, this activity led to speculation that these proteins function as global repressors of transcription. However, work from numerous systems has demonstrated that this is not the case, and that linker histones appear to affect only the transcription of a small subset of genes, and, in fact, act to activate as well as repress transcription. Furthermore, there is evidence that suggests that linker histones are not required for mitotic condensation. In this review, we focus on studies of biological functions of linker histones primarily performed in unicellular eukaryotes. We highlight recent developments pointing towards linker histone involvement in DNA repair and ageing, which raise the possibility that the biological functions of linker histones are more varied than previously imagined.
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Affiliation(s)
- Anne C Harvey
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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44
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Kiefer HLB, Hanley TM, Marcello JE, Karthik AG, Viglianti GA. Retinoic acid inhibition of chromatin remodeling at the human immunodeficiency virus type 1 promoter. Uncoupling of histone acetylation and chromatin remodeling. J Biol Chem 2004; 279:43604-13. [PMID: 15299018 DOI: 10.1074/jbc.m408069200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
All-trans retinoic acid (RA) represses HIV-1 transcription and replication in cultured monocytic cells and in primary monocyte-derived macrophages. Here we examine the role of histone acetylation and chromatin remodeling in RA-mediated repression. RA pretreatment of latently infected U1 promonocytes inhibits HIV-1 expression in response to the histone deacetylase (HDAC) inhibitor, trichostatin A (TSA). TSA is thought to activate HIV-1 transcription by inducing histone hyperacetylation within a regulatory nucleosome, nuc-1, positioned immediately downstream from the transcription start site. Acetylation of nuc-1 is thought to be a critical step in activation that precedes nuc-1 remodeling and, subsequently, transcriptional initiation. Here we demonstrate that TSA treatment induces H3 and H4 hyperacetylation and nuc-1 remodeling. Although RA pretreatment inhibits nuc-1 remodeling and HIV-1 transcription, it has no effect on histone acetylation. This suggests that acetylation and remodeling are not obligatorily coupled. We also show that growth of U1 cells in retinoid-deficient medium induces nuc-1 remodeling and HIV-1 expression but does not induce histone hyperacetylation. These findings suggest that remodeling, not histone hyperacetylation, is the limiting step in transcriptional activation in these cells. Together, these data suggest that RA signaling maintains the chromatin structure of the HIV-1 promoter in a transcriptionally non-permissive state that may contribute to the establishment of latency in monocyte/macrophages.
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Affiliation(s)
- Heather L B Kiefer
- Department of Microbiology, Boston University School of Medicine, Massachusetts 02118, USA
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45
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Catez F, Yang H, Tracey KJ, Reeves R, Misteli T, Bustin M. Network of dynamic interactions between histone H1 and high-mobility-group proteins in chromatin. Mol Cell Biol 2004; 24:4321-8. [PMID: 15121851 PMCID: PMC400478 DOI: 10.1128/mcb.24.10.4321-4328.2004] [Citation(s) in RCA: 211] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Histone H1 and the high-mobility group (HMG) proteins are chromatin binding proteins that regulate gene expression by modulating the compactness of the chromatin fiber and affecting the ability of regulatory factors to access their nucleosomal targets. Histone H1 stabilizes the higher-order chromatin structure and decreases nucleosomal access, while the HMG proteins decrease the compactness of the chromatin fiber and enhance the accessibility of chromatin targets to regulatory factors. Here we show that in living cells, each of the three families of HMG proteins weakens the binding of H1 to nucleosomes by dynamically competing for chromatin binding sites. The HMG families weaken H1 binding synergistically and do not compete among each other, suggesting that they affect distinct H1 binding sites. We suggest that a network of dynamic and competitive interactions involving HMG proteins and H1, and perhaps other structural proteins, constantly modulates nucleosome accessibility and the local structure of the chromatin fiber.
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Affiliation(s)
- Frédéric Catez
- National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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46
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Kinyamu HK, Archer TK. Modifying chromatin to permit steroid hormone receptor-dependent transcription. ACTA ACUST UNITED AC 2004; 1677:30-45. [PMID: 15020043 DOI: 10.1016/j.bbaexp.2003.09.015] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2003] [Revised: 09/24/2003] [Accepted: 09/24/2003] [Indexed: 02/07/2023]
Abstract
Lipophilic hormones, including steroids, exert their physiological effects through binding to high-affinity superfamily of steroid hormone receptor (SR) proteins that function as ligand-dependent DNA binding transcription factors. To date, SR proteins are among a few transcription factors shown to directly interact with higher order chromatin structures to regulate gene expression. To perturb chromatin, SRs employ enzymatic multicomplexes that can either remodel or modify chromatin. Here we examine the current state of knowledge concerning multicomplex chromatin remodeling/modification machines and SR-dependent transcription. We will focus on the role of these protein-protein and chromatin-protein interactions in vivo with the MMTV promoter as a primary model. In addition, we discuss emerging evidence implicating chaperone proteins and proteasome degradation machinery in SR-mediated gene regulation within chromatin.
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Affiliation(s)
- H Karimi Kinyamu
- Chromatin and Gene Expression Section, Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, 111 Alexander Drive, PO Box 12233 (MD E4-06), Research Triangle Park, NC 27709, USA
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47
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Bonaldi T, Längst G, Strohner R, Becker PB, Bianchi ME. The DNA chaperone HMGB1 facilitates ACF/CHRAC-dependent nucleosome sliding. EMBO J 2004. [PMID: 12486007 DOI: 10.1093/embo/cdf692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Nucleosome remodelling complexes CHRAC and ACF contribute to chromatin dynamics by converting chemical energy into sliding of histone octamers on DNA. Their shared ATPase subunit ISWI binds DNA at the sites of entry into the nucleosome. A prevalent model assumes that DNA distortions catalysed by ISWI are converted into relocation of DNA relative to a histone octamer. HMGB1, one of the most abundant nuclear non-histone proteins, binds with preference to distorted DNA. We have now found that transient interaction of HMGB1 with nucleosomal linker DNA overlapping ISWI-binding sites enhances the ability of ACF to bind nucleosomal DNA and accelerates the sliding activity of limiting concentrations of remodelling factor. By contrast, an HMGB1 mutant with increased binding affinity was inhibitory. These observations are consistent with a role for HMGB1 as a DNA chaperone facilitating the rate-limiting DNA distortion during nucleosome remodelling.
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Affiliation(s)
- Tiziana Bonaldi
- Adolf-Butenandt Institut, Molekularbiologie, Schillerstrasse 44, D-80336 München, Germany
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48
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Ragab A, Travers A. HMG-D and histone H1 alter the local accessibility of nucleosomal DNA. Nucleic Acids Res 2004; 31:7083-9. [PMID: 14654683 PMCID: PMC291865 DOI: 10.1093/nar/gkg923] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
There is evidence that HMGB proteins facilitate, while linker histones inhibit chromatin remodelling, respectively. We have examined the effects of HMG-D and histone H1/H5 on accessibility of nucleosomal DNA. Using the 601.2 nucleosome positioning sequence designed by Widom and colleagues we assembled nucleosomes in vitro and probed DNA accessibility with restriction enzymes in the presence or absence of HMG-D and histone H1/H5. For HMG-D our results show increased digestion at two spatially adjacent sites, the dyad and one terminus of nucleosomal DNA. Elsewhere varying degrees of protection from digestion were observed. The C-terminal acidic tail of HMG-D is essential for this pattern of accessibility. Neither the HMG domain by itself nor in combination with the adjacent basic region is sufficient. Histone H1/H5 binding produces two sites of increased digestion on opposite faces of the nucleosome and decreased digestion at all other sites. Our results provide the first evidence of local changes in the accessibility of nucleosomal DNA upon separate interaction with two linker binding proteins.
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Affiliation(s)
- Anan Ragab
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
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49
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Ausió J, Abbott D. The role of histone variability in chromatin stability and folding. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/s0167-7306(03)39010-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2023]
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50
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Abstract
The study of chromatin and how this dynamic structure modulates events in the eukaryotic nucleus has become an increasingly important topic in biomedical research. A large number of enzymes have been discovered that are responsible for modifying and altering chromatin structure, either globally or specifically at particular gene promoters or regions of the chromosome. This chapter provides an introduction to the structure of chromatin and then describes how special classes of enzymes modulate chromatin structure to allow access to DNA.
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Affiliation(s)
- Corey L Smith
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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