1
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Gao E, Brown JAR, Jung S, Howe LJ. A fluorescent assay for cryptic transcription in Saccharomyces cerevisiae reveals novel insights into factors that stabilize chromatin structure on newly replicated DNA. Genetics 2024; 226:iyae016. [PMID: 38407959 PMCID: PMC10990430 DOI: 10.1093/genetics/iyae016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 01/12/2024] [Indexed: 02/27/2024] Open
Abstract
The disruption of chromatin structure can result in transcription initiation from cryptic promoters within gene bodies. While the passage of RNA polymerase II is a well-characterized chromatin-disrupting force, numerous factors, including histone chaperones, normally stabilize chromatin on transcribed genes, thereby repressing cryptic transcription. DNA replication, which employs a partially overlapping set of histone chaperones, is also inherently disruptive to chromatin, but a role for DNA replication in cryptic transcription has never been examined. In this study, we tested the hypothesis that, in the absence of chromatin-stabilizing factors, DNA replication can promote cryptic transcription in Saccharomyces cerevisiae. Using a novel fluorescent reporter assay, we show that multiple factors, including Asf1, CAF-1, Rtt106, Spt6, and FACT, block transcription from a cryptic promoter, but are entirely or partially dispensable in G1-arrested cells, suggesting a requirement for DNA replication in chromatin disruption. Collectively, these results demonstrate that transcription fidelity is dependent on numerous factors that function to assemble chromatin on nascent DNA.
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Affiliation(s)
- Ellia Gao
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Joshua A R Brown
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Stephanie Jung
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - LeAnn J Howe
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
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2
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Robert F, Jeronimo C. Transcription-coupled nucleosome assembly. Trends Biochem Sci 2023; 48:978-992. [PMID: 37657993 DOI: 10.1016/j.tibs.2023.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 07/21/2023] [Accepted: 08/04/2023] [Indexed: 09/03/2023]
Abstract
Eukaryotic transcription occurs on chromatin, where RNA polymerase II encounters nucleosomes during elongation. These nucleosomes must unravel for the DNA to enter the active site. However, in most transcribed genes, nucleosomes remain intact due to transcription-coupled chromatin assembly mechanisms. These mechanisms primarily involve the local reassembly of displaced nucleosomes to prevent (epi)genomic instability and the emergence of cryptic transcription. As a fail-safe mechanism, cells can assemble nucleosomes de novo, particularly in highly transcribed genes, but this may result in the loss of epigenetic information. This review examines transcription-coupled chromatin assembly, with an emphasis on studies in yeast and recent structural studies. These studies shed light on how elongation factors and histone chaperones coordinate to enable nucleosome recycling during transcription.
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Affiliation(s)
- François Robert
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada; Département de Médecine, Faculté de Médecine, Université de Montréal, 2900 Boul. Édouard-Montpetit, Montréal, QC H3T 1J4, Canada; Faculty of Medicine, Division of Experimental Medicine, McGill University, Montréal, QC H3A 1A3, Canada.
| | - Célia Jeronimo
- Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada
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3
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Ma M, Zhang X, Zheng Y, Lu S, Pan X, Mao X, Pan H, Chung HL, Wang H, Guo H, Bellen HJ. The fly homolog of SUPT16H, a gene associated with neurodevelopmental disorders, is required in a cell-autonomous fashion for cell survival. Hum Mol Genet 2023; 32:984-997. [PMID: 36255738 PMCID: PMC9991001 DOI: 10.1093/hmg/ddac259] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 09/22/2022] [Accepted: 10/14/2022] [Indexed: 11/14/2022] Open
Abstract
SUPT16H encodes the large subunit of the FAcilitate Chromatin Transcription (FACT) complex, which functions as a nucleosome organizer during transcription. We identified two individuals from unrelated families carrying de novo missense variants in SUPT16H. The probands exhibit global developmental delay, intellectual disability, epilepsy, facial dysmorphism and brain structural abnormalities. We used Drosophila to characterize two variants: p.T171I and p.G808R. Loss of the fly ortholog, dre4, causes lethality at an early developmental stage. RNAi-mediated knockdown of dre4 in either glia or neurons causes severely reduced eclosion and longevity. Tissue-specific knockdown of dre4 in the eye or wing leads to the loss of these tissues, whereas overexpression of SUPT16H has no dominant effect. Moreover, expression of the reference SUPT16H significantly rescues the loss-of-function phenotypes in the nervous system as well as wing and eye. In contrast, expression of SUPT16H p.T171I or p.G808R rescues the phenotypes poorly, indicating that the variants are partial loss-of-function alleles. While previous studies argued that the developmental arrest caused by loss of dre4 is due to impaired ecdysone production in the prothoracic gland, our data show that dre4 is required for proper cell growth and survival in multiple tissues in a cell-autonomous manner. Altogether, our data indicate that the de novo loss-of-function variants in SUPT16H are indeed associated with developmental and neurological defects observed in the probands.
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Affiliation(s)
- Mengqi Ma
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Xi Zhang
- National Health Commission Key Laboratory of Birth Defects Research, Prevention and Treatment, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan 410008, China
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Yiming Zheng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Shenzhao Lu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Xueyang Pan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Xiao Mao
- National Health Commission Key Laboratory of Birth Defects Research, Prevention and Treatment, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan 410008, China
- Department of Medical Genetics, Maternal and Child Health Hospital of Hunan Province, Changsha, Hunan 410008, China
| | - Hongling Pan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Hyung-lok Chung
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Hua Wang
- National Health Commission Key Laboratory of Birth Defects Research, Prevention and Treatment, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan 410008, China
- Department of Medical Genetics, Hunan Children’s Hospital, Changsha, Hunan 410007, China
| | - Hong Guo
- Department of Medical Genetics, Army Medical University, Chongqing 400038, China
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
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4
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Jeong E, Martina JA, Contreras PS, Lee J, Puertollano R. The FACT complex facilitates expression of lysosomal and antioxidant genes through binding to TFEB and TFE3. Autophagy 2022; 18:2333-2349. [PMID: 35230915 PMCID: PMC9542721 DOI: 10.1080/15548627.2022.2029671] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
TFEB (transcription factor EB) and TFE3 (transcription factor binding to IGHM enhancer 3) orchestrate the cellular response to a variety of stressors, including nutrient deprivation, oxidative stress and pathogens. Here we describe a novel interaction of TFEB and TFE3 with the FAcilitates Chromatin Transcription (FACT) complex, a heterodimeric histone chaperone consisting of SSRP1 and SUPT16H that mediates nucleosome disassembly and assembly, thus facilitating transcription. Extracellular stimuli, such as nutrient deprivation or oxidative stress, induce nuclear translocation and activation of TFEB and TFE3, which then associate with the FACT complex to regulate stress-induced gene transcription. Depletion of FACT does not affect TFEB activation, stability, or binding to the promoter of target genes. In contrast, reduction of FACT levels by siRNA or treatment with the FACT inhibitor curaxin, severely impairs induction of numerous antioxidant and lysosomal genes, revealing a crucial role of FACT as a regulator of cellular homeostasis. Furthermore, upregulation of antioxidant genes induced by TFEB over-expression is significantly reduced by curaxin, consistent with a role of FACT as a TFEB transcriptional activator. Together, our data show that chromatin remodeling at the promoter of stress-responsive genes by FACT is important for efficient expression of TFEB and TFE3 targets, thus providing a link between environmental changes, chromatin modifications and transcriptional regulation.Abbreviations: ADNP2, ADNP homeobox 2; ATP6V0D1, ATPase H+ transporting V0 subunit d1; ATP6V1A, ATPase H+ transporting V1 subunit A; ATP6V1C1, ATPase H+ transporting V1 subunit C1; CSNK2/CK2, casein kinase 2; CLCN7, chloride voltage-gated channel 7; CTSD, cathepsin D; CTSZ, cathepsin Z; EBSS, earle's balanced salt solution; FACT complex, facilitates chromatin transcription complex; FOXO3, forkhead box O3; HEXA, hexosaminidase subunit alpha; HIF1A, hypoxia inducible factor 1 subunit alpha; HMOX1, heme oxygenase 1; LAMP1, lysosomal associated membrane protein 1; MAFF, MAF bZIP transcription factor F; MAFG, MAF bZIP transcription factor G; MCOLN1, mucolipin TRP cation channel 1; MTORC1, mechanistic target of rapamycin kinase complex 1; NaAsO2, sodium arsenite; POLR2, RNA polymerase II; PPARGC1A, PPARG coactivator 1 alpha; PYROXD1, pyridine nucleotide-disulfide oxidoreductase domain 1; RRAGC, Ras related GTP binding C; SEC13, SEC13 homolog, nuclear pore and COPII coat complex component; SLC38A9, solute carrier family 38 member 9; SSRP1, structure specific recognition protein 1; SUPT16H, SPT16 homolog, facilitates chromatin remodeling subunit; TFEB, transcription factor EB; TFE3, transcription factor binding to IGHM enhancer 3; TXNRD1, thioredoxin reductase 1; UVRAG, UV radiation resistance associated; WDR59, WD repeat domain 59.
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Affiliation(s)
- Eutteum Jeong
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - José A. Martina
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Pablo S. Contreras
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Juhyung Lee
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Rosa Puertollano
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA,CONTACT Rosa Puertollano Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
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5
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Jeronimo C, Robert F. The histone chaperone FACT: a guardian of chromatin structure integrity. Transcription 2022; 13:16-38. [PMID: 35485711 PMCID: PMC9467567 DOI: 10.1080/21541264.2022.2069995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The identification of FACT as a histone chaperone enabling transcription through chromatin in vitro has strongly shaped how its roles are envisioned. However, FACT has been implicated in essentially all aspects of chromatin biology, from transcription to DNA replication, DNA repair, and chromosome segregation. In this review, we focus on recent literature describing the role and mechanisms of FACT during transcription. We highlight the prime importance of FACT in preserving chromatin integrity during transcription and challenge its role as an elongation factor. We also review evidence for FACT's role as a cell-type/gene-specificregulator of gene expression and briefly summarize current efforts at using FACT inhibition as an anti-cancerstrategy.
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Affiliation(s)
- Célia Jeronimo
- Institut de recherches cliniques de Montréal, Montréal, Québec, Canada
| | - François Robert
- Institut de recherches cliniques de Montréal, Montréal, Québec, Canada.,Département de Médecine, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada.,Faculty of Medicine, Division of Experimental Medicine, McGill University, Montréal, Québec, Canada
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6
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Safaric B, Chacin E, Scherr MJ, Rajappa L, Gebhardt C, Kurat CF, Cordes T, Duderstadt KE. The fork protection complex recruits FACT to reorganize nucleosomes during replication. Nucleic Acids Res 2022; 50:1317-1334. [PMID: 35061899 PMCID: PMC8860610 DOI: 10.1093/nar/gkac005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/21/2021] [Accepted: 01/05/2022] [Indexed: 01/14/2023] Open
Abstract
Chromosome replication depends on efficient removal of nucleosomes by accessory factors to ensure rapid access to genomic information. Here, we show this process requires recruitment of the nucleosome reorganization activity of the histone chaperone FACT. Using single-molecule FRET, we demonstrate that reorganization of nucleosomal DNA by FACT requires coordinated engagement by the middle and C-terminal domains of Spt16 and Pob3 but does not require the N-terminus of Spt16. Using structure-guided pulldowns, we demonstrate instead that the N-terminal region is critical for recruitment by the fork protection complex subunit Tof1. Using in vitro chromatin replication assays, we confirm the importance of these interactions for robust replication. Our findings support a mechanism in which nucleosomes are removed through the coordinated engagement of multiple FACT domains positioned at the replication fork by the fork protection complex.
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Affiliation(s)
- Barbara Safaric
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Erika Chacin
- Biomedical Center (BMC), Division of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Planegg, Germany
| | - Matthias J Scherr
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Lional Rajappa
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Christian Gebhardt
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152 Planegg-Martinsried, Germany
| | - Christoph F Kurat
- Biomedical Center (BMC), Division of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Planegg, Germany
| | - Thorben Cordes
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152 Planegg-Martinsried, Germany
| | - Karl E Duderstadt
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.,Physics Department, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
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7
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Leng H, Liu S, Lei Y, Tang Y, Gu S, Hu J, Chen S, Feng J, Li Q. FACT interacts with Set3 HDAC and fine-tunes GAL1 transcription in response to environmental stimulation. Nucleic Acids Res 2021; 49:5502-5519. [PMID: 33963860 PMCID: PMC8191775 DOI: 10.1093/nar/gkab312] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/13/2021] [Accepted: 04/20/2021] [Indexed: 01/22/2023] Open
Abstract
The histone chaperone facilitates chromatin transactions (FACT) functions in various DNA transactions. How FACT performs these multiple functions remains largely unknown. Here, we found, for the first time, that the N-terminal domain of its Spt16 subunit interacts with the Set3 histone deacetylase complex (Set3C) and that FACT and Set3C function in the same pathway to regulate gene expression in some settings. We observed that Spt16-G132D mutant proteins show defects in binding to Set3C but not other reported FACT interactors. At the permissive temperature, induction of the GAL1 and GAL10 genes is reduced in both spt16-G132D and set3Δ cells, whereas transient upregulation of GAL10 noncoding RNA (ncRNA), which is transcribed from the 3′ end of the GAL10 gene, is elevated. Mutations that inhibit GAL10 ncRNA transcription reverse the GAL1 and GAL10 induction defects in spt16-G132D and set3Δ mutant cells. Mechanistically, set3Δ and FACT (spt16-G132D) mutants show reduced histone acetylation and increased nucleosome occupancy at the GAL1 promoter under inducing conditions and inhibition of GAL10 ncRNA transcription also partially reverses these chromatin changes. These results indicate that FACT interacts with Set3C, which in turn prevents uncontrolled GAL10 ncRNA expression and fine-tunes the expression of GAL genes upon a change in carbon source.
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Affiliation(s)
- He Leng
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Shaofeng Liu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Yang Lei
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Yuantao Tang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Shijia Gu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Jiazhi Hu
- The MOE Key Laboratory of Cell Proliferation and Differentiation, Genome Editing Research Center, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - She Chen
- National Institute of Biological Sciences, Beijing 102206, China
| | - Jianxun Feng
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Qing Li
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
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8
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Shukla A, Bhalla P, Potdar PK, Jampala P, Bhargava P. Transcription-dependent enrichment of the yeast FACT complex influences nucleosome dynamics on the RNA polymerase III-transcribed genes. RNA (NEW YORK, N.Y.) 2020; 27:rna.077974.120. [PMID: 33277439 PMCID: PMC7901838 DOI: 10.1261/rna.077974.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 11/30/2020] [Indexed: 05/04/2023]
Abstract
The FACT (FAcilitates Chromatin Transactions) complex influences transcription initiation and enables passage of RNA polymerase (pol) II through gene body nucleosomes during elongation. In the budding yeast, ~280 non-coding RNA genes highly transcribed in vivo by pol III are found in the nucleosome-free regions bordered by positioned nucleosomes. The downstream nucleosome dynamics was found to regulate transcription via controlling the gene terminator accessibility and hence, terminator-dependent pol III recycling. As opposed to the enrichment at the 5'-ends of pol II-transcribed genes, our genome-wide mapping found transcription-dependent enrichment of the FACT subunit Spt16 near the 3'-end of all pol III-transcribed genes. Spt16 physically associates with the pol III transcription complex and shows gene-specific occupancy levels on the individual genes. On the non-tRNA pol III-transcribed genes, Spt16 facilitates transcription by reducing the nucleosome occupany on the gene body. On the tRNA genes, it maintains the position of the nucleosome at the 3' gene-end and affects transcription in gene-specific manner. Under nutritional stress, Spt16 enrichment is abolished in the gene downstream region of all pol III-transcribed genes and reciprocally changed on the induced or repressed pol II-transcribed ESR genes. Under the heat and replicative stress, its occupancy on the pol III-transcribed genes increases significantly. Our results show that Spt16 elicits a differential, gene-specific and stress-responsive dynamics, which provides a novel stress-sensor mechanism of regulating transcription against external stress. By primarily influencing the nucleosomal organization, FACT links the downstream nucleosome dynamics to transcription and environmental stress on the pol III-transcribed genes.
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9
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Formosa T, Winston F. The role of FACT in managing chromatin: disruption, assembly, or repair? Nucleic Acids Res 2020; 48:11929-11941. [PMID: 33104782 PMCID: PMC7708052 DOI: 10.1093/nar/gkaa912] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/01/2020] [Accepted: 10/05/2020] [Indexed: 12/20/2022] Open
Abstract
FACT (FAcilitates Chromatin Transcription) has long been considered to be a transcription elongation factor whose ability to destabilize nucleosomes promotes RNAPII progression on chromatin templates. However, this is just one function of this histone chaperone, as FACT also functions in DNA replication. While broadly conserved among eukaryotes and essential for viability in many organisms, dependence on FACT varies widely, with some differentiated cells proliferating normally in its absence. It is therefore unclear what the core functions of FACT are, whether they differ in different circumstances, and what makes FACT essential in some situations but not others. Here, we review recent advances and propose a unifying model for FACT activity. By analogy to DNA repair, we propose that the ability of FACT to both destabilize and assemble nucleosomes allows it to monitor and restore nucleosome integrity as part of a system of chromatin repair, in which disruptions in the packaging of DNA are sensed and returned to their normal state. The requirement for FACT then depends on the level of chromatin disruption occurring in the cell, and the cell's ability to tolerate packaging defects. The role of FACT in transcription would then be just one facet of a broader system for maintaining chromatin integrity.
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Affiliation(s)
- Tim Formosa
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Fred Winston
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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10
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Histone chaperone FACT is essential to overcome replication stress in mammalian cells. Oncogene 2020; 39:5124-5137. [PMID: 32533099 PMCID: PMC7343669 DOI: 10.1038/s41388-020-1346-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 05/11/2020] [Accepted: 06/01/2020] [Indexed: 12/15/2022]
Abstract
The histone chaperone FACT is upregulated during mammary tumorigenesis and necessary for the viability and growth of breast tumor cells. We established that only proliferating tumor cells are sensitive to FACT knockdown, suggesting that FACT functions during DNA replication in tumor cells but not in normal cells. We hypothesized that the basal level of replication stress defines the FACT dependence of cells. Using genetic and chemical tools, we demonstrated that FACT is needed to overcome replication stress. In the absence of FACT during replication stress, the MCM2-7 helicase dissociates from chromatin, resulting in the absence of ssDNA accumulation, RPA binding, and activation of the ATR/CHK1 checkpoint response. Without this response, stalled replication forks are not stabilized, and new origin firing cannot be prevented, leading to the accumulation of DNA damage and cell death. Thus, we propose a novel role for FACT as a factor preventing helicase dissociation from chromatin during replication stress.
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11
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Chang HW, Nizovtseva EV, Razin SV, Formosa T, Gurova KV, Studitsky VM. Histone Chaperone FACT and Curaxins: Effects on Genome Structure and Function. ACTA ACUST UNITED AC 2019; 5. [PMID: 31853507 DOI: 10.20517/2394-4722.2019.31] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The histone chaperone FACT plays important roles in essentially every chromatin-associated process and is an important indirect target of the curaxin class of anti-cancer drugs. Curaxins are aromatiс compounds that intercalate into DNA and can trap FACT in bulk chromatin, thus interfering with its distribution and its functions in cancer cells. Recent studies have provided mechanistic insight into how FACT and curaxins cooperate to promote unfolding of nucleosomes and chromatin fibers, resulting in genome-wide disruption of contact chromatin domain boundaries, perturbation of higher order chromatin organization, and global disregulation of gene expression. Here, we discuss the implications of these insights for cancer biology.
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Affiliation(s)
- Han-Wen Chang
- Cancer Epigenetics Program, Fox Chase Cancer Center, 333 Cottman Ave., Philadelphia, PA 19422, USA
| | - Ekaterina V Nizovtseva
- Cancer Epigenetics Program, Fox Chase Cancer Center, 333 Cottman Ave., Philadelphia, PA 19422, USA
| | - Sergey V Razin
- Institute of Gene Biology RAS, 34/5 Vavilov Str., 119334 Moscow, Russia.,Biology Faculty, Lomonosov Moscow State University, 1 Leninskie Gory, 119992 Moscow, Russia
| | - Tim Formosa
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84132, USA
| | - Katerina V Gurova
- Department of Cell Stress Biology, Roswell Park Cancer Institute, Elm and Carlton St, Buffalo, NY14263, USA
| | - Vasily M Studitsky
- Cancer Epigenetics Program, Fox Chase Cancer Center, 333 Cottman Ave., Philadelphia, PA 19422, USA.,Biology Faculty, Lomonosov Moscow State University, 1 Leninskie Gory, 119992 Moscow, Russia
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12
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Gurova K, Chang HW, Valieva ME, Sandlesh P, Studitsky VM. Structure and function of the histone chaperone FACT - Resolving FACTual issues. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2018; 1861:S1874-9399(18)30159-7. [PMID: 30055319 PMCID: PMC6349528 DOI: 10.1016/j.bbagrm.2018.07.008] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/17/2018] [Accepted: 07/19/2018] [Indexed: 12/12/2022]
Abstract
FAcilitates Chromatin Transcription (FACT) has been considered essential for transcription through chromatin mostly based on cell-free experiments. However, FACT inactivation in cells does not cause a significant reduction in transcription. Moreover, not all mammalian cells require FACT for viability. Here we synthesize information from different organisms to reveal the core function(s) of FACT and propose a model that reconciles the cell-free and cell-based observations. We describe FACT structure and nucleosomal interactions, and their roles in FACT-dependent transcription, replication and repair. The variable requirements for FACT among different tumor and non-tumor cells suggest that various FACT-dependent processes have significantly different levels of relative importance in different eukaryotic cells. We propose that the stability of chromatin, which might vary among different cell types, dictates these diverse requirements for FACT to support cell viability. Since tumor cells are among the most sensitive to FACT inhibition, this vulnerability could be exploited for cancer treatment.
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Affiliation(s)
- Katerina Gurova
- Department of Cell Stress Biology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA.
| | - Han-Wen Chang
- Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Maria E Valieva
- Biology Faculty, Lomonosov Moscow State University, Moscow, Russia
| | - Poorva Sandlesh
- Department of Cell Stress Biology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA
| | - Vasily M Studitsky
- Fox Chase Cancer Center, Philadelphia, PA 19111, USA; Biology Faculty, Lomonosov Moscow State University, Moscow, Russia.
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13
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H3K4 Methylation Dependent and Independent Chromatin Regulation by JHD2 and SET1 in Budding Yeast. G3-GENES GENOMES GENETICS 2018; 8:1829-1839. [PMID: 29599176 PMCID: PMC5940172 DOI: 10.1534/g3.118.200151] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Set1 and Jhd2 regulate the methylation state of histone H3 lysine-4 (H3K4me) through their opposing methyltransferase and demethylase activities in the budding yeast Saccharomyces cerevisiae. H3K4me associates with actively transcribed genes and, like both SET1 and JHD2 themselves, is known to regulate gene expression diversely. It remains unclear, however, if Set1 and Jhd2 act solely through H3K4me. Relevantly, Set1 methylates lysine residues in the kinetochore protein Dam1 while genetic studies of the S. pombe SET1 ortholog suggest the existence of non-H3K4 Set1 targets relevant to gene regulation. We interrogated genetic interactions of JHD2 and SET1 with essential genes involved in varied aspects of the transcription cycle. Our findings implicate JHD2 in genetic inhibition of the histone chaperone complexes Spt16-Pob3 (FACT) and Spt6-Spn1. This targeted screen also revealed that JHD2 inhibits the Nrd1-Nab3-Sen1 (NNS) transcription termination complex. We find that while Jhd2’s impact on these transcription regulatory complexes likely acts via H3K4me, Set1 governs the roles of FACT and NNS through opposing H3K4-dependent and -independent functions. We also identify diametrically opposing consequences for mutation of H3K4 to alanine or arginine, illuminating that caution must be taken in interpreting histone mutation studies. Unlike FACT and NNS, detailed genetic studies suggest an H3K4me-centric mode of Spt6-Spn1 regulation by JHD2 and SET1. Chromatin immunoprecipitation and transcript quantification experiments show that Jhd2 opposes the positioning of a Spt6-deposited nucleosome near the transcription start site of SER3, a Spt6-Spn1 regulated gene, leading to hyper-induction of SER3. In addition to confirming and extending an emerging role for Jhd2 in the control of nucleosome occupancy near transcription start sites, our findings suggest some of the chromatin regulatory functions of Set1 are independent of H3K4 methylation.
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14
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Guo Y, Wang Z, Guan X, Hu Z, Zhang Z, Zheng J, Lu Y. Proteomic analysis of Potentilla fruticosa L. leaves by iTRAQ reveals responses to heat stress. PLoS One 2017; 12:e0182917. [PMID: 28829780 PMCID: PMC5568749 DOI: 10.1371/journal.pone.0182917] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 07/26/2017] [Indexed: 11/19/2022] Open
Abstract
High temperature is an important environmental factor that affects plant growth and crop yield. Potentilla fruticosa L. has a developed root system and characteristics of resistance to several stresses (e.g., high temperature, cold, drought) that are shared by native shrubs in the north and west of China. To investigate thermotolerance mechanisms in P. fruticosa, 3-year-old plants were subjected to a high temperature of 42°C for 1, 2, and 3 days respectively before analysis. Then, we studied changes in cell ultrastructure using electron microscopy and investigated physiological changes in the leaves of P. fruticosa. Additionally, we used isobaric tags for relative and absolute quantification (iTRAQ) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to study proteomic changes in P. fruticosa leaves after 3 d of 42°C heat stress. we found that the cell membrane and structure of chloroplasts, especially the thylakoids in P. fruticosa leaves, was destroyed by a high temperature stress, which might affect the photosynthesis in this species. We identified 35 up-regulated and 23 down-regulated proteins after the heat treatment. Gene Ontology (GO) analysis indicated that these 58 differentially abundant proteins were involved mainly in protein synthesis, protein folding and degradation, abiotic stress defense, photosynthesis, RNA process, signal transduction, and other functions. The 58 proteins fell into different categories based on their subcellular localization mainly in the chloroplast envelope, cytoplasm, nucleus, cytosol, chloroplast, mitochondrion and cell membrane. Five proteins were selected for analysis at the mRNA level; this analysis showed that gene transcription levels were not completely consistent with protein abundance. These results provide valuable information for Potentilla thermotolerance breeding.
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Affiliation(s)
- Yingtian Guo
- College of Landscape Architecture, Beijing University of Agriculture, Beijing, China
| | - Zhi Wang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Xuelian Guan
- College of Landscape Architecture, Beijing University of Agriculture, Beijing, China
| | - Zenghui Hu
- College of Landscape Architecture, Beijing University of Agriculture, Beijing, China
| | - Ze Zhang
- College of Landscape Architecture, Beijing University of Agriculture, Beijing, China
| | - Jian Zheng
- College of Landscape Architecture, Beijing University of Agriculture, Beijing, China
- Beijing Collaborative Innovation Center for Eco-Environmental Improvement with Forestry and Fruit Trees, Beijing, China
| | - Yizeng Lu
- Shandong Forest Germplasm Resources Center, Jinan City, Shandong Province, China
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15
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Are VN, Ghosh B, Kumar A, Gadre R, Makde RD. Crystal structure and dynamics of Spt16N-domain of FACT complex from Cicer arietinum. Int J Biol Macromol 2016; 88:36-43. [PMID: 26995613 DOI: 10.1016/j.ijbiomac.2016.03.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 02/24/2016] [Accepted: 03/15/2016] [Indexed: 11/18/2022]
Abstract
The facilitates chromatin transcription (FACT) complex, a heterodimer of SSRP1 and Spt16 proteins, is an essential histone chaperone that transiently reorganizes nucleosomes during transcription, replication and repair. N-terminal domain of Spt16 subunit (Spt16N) is strictly conserved in all the known Spt16 orthologs. Genetic studies in yeast have revealed a partially redundant role of Spt16N for the FACT functionality. Here, we report the crystal structure of Spt16N from a plant origin (Spt16Nca, Cicer arietinum) and its comparisons with the known Spt16N structures from yeasts and human. The inter-domain angle in Spt16Nca is significantly different from that of the yeast and human Spt16N structures. Normal mode analysis and classical molecular dynamics simulations reveal inter-domain movement in Spt16Nca and later also shows conformational flexibility of the critical loops. Spt16Nca binds to histone H3/H4 complex, similar to its orthologs from yeast and human origins. Further, conservation of electrostatic surface potentials in Spt16N structures from evolutionary distinct domains of eukaryotes (plant, human and fungi) have provided the potential sites on Spt16N for histone interactions. The structural comparisons with M24 peptidases show that the hydrophobic pocket shielded by a flexible loop of C-terminal domain of Spt16N that may be functionally important.
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Affiliation(s)
- Venkat N Are
- High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai, India; School of Biochemistry, Devi Ahilya University, Indore, India
| | - Biplab Ghosh
- High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Ashwani Kumar
- High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Rekha Gadre
- School of Biochemistry, Devi Ahilya University, Indore, India
| | - Ravindra D Makde
- High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai, India.
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16
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Marcianò G, Huang DT. Structure of the human histone chaperone FACT Spt16 N-terminal domain. Acta Crystallogr F Struct Biol Commun 2016; 72:121-8. [PMID: 26841762 PMCID: PMC4741192 DOI: 10.1107/s2053230x15024565] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 12/21/2015] [Indexed: 11/16/2022] Open
Abstract
The histone chaperone FACT plays an important role in facilitating nucleosome assembly and disassembly during transcription. FACT is a heterodimeric complex consisting of Spt16 and SSRP1. The N-terminal domain of Spt16 resembles an inactive aminopeptidase. How this domain contributes to the histone chaperone activity of FACT remains elusive. Here, the crystal structure of the N-terminal domain (NTD) of human Spt16 is reported at a resolution of 1.84 Å. The structure adopts an aminopeptidase-like fold similar to those of the Saccharomyces cerevisiae and Schizosaccharomyces pombe Spt16 NTDs. Isothermal titration calorimetry analyses show that human Spt16 NTD binds histones H3/H4 with low-micromolar affinity, suggesting that Spt16 NTD may contribute to histone binding in the FACT complex. Surface-residue conservation and electrostatic analysis reveal a conserved acidic patch that may be involved in histone binding.
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Affiliation(s)
- G. Marcianò
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, Scotland
| | - D. T. Huang
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, Scotland
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17
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Hoffmann C, Neumann H. In Vivo Mapping of FACT-Histone Interactions Identifies a Role of Pob3 C-terminus in H2A-H2B Binding. ACS Chem Biol 2015; 10:2753-63. [PMID: 26414936 DOI: 10.1021/acschembio.5b00493] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Histone chaperones assist nucleosomal rearrangements to facilitate the passage of DNA and RNA polymerases through chromatin. The FACT (facilitates chromatin transcription) complex is a conserved histone chaperone involved in transcription, replication, and repair. The complex consists of two major subunits, Spt16 and SSRP1/Pob3 in mammals and yeast, which engage histones and DNA by multiple contacts. However, the precise mechanism of FACT function is largely unclear. Here, we used the genetically installed UV-activatable cross-linker amino acid p-benzoylphenylalanine (pBPA) to map the interaction network of FACT in living yeast. Unexpectedly, we found the acidic C-terminus of Pob3 forming cross-links to histone H2A and H2B most efficiently. This observation was independent of the performed cross-linking chemistry since similar histone cross-links were obtained using p-azidophenylalanine (pAzF). Further analyses identified a C-terminal nuclear localization sequence in Pob3. Its interaction with Importin-α interfered with H2A-H2B binding, which suggests a possible regulatory role in FACT recruitment to chromatin. Deletion of acidic residues from the Pob3 C-terminus creates a hydroxyurea-sensitive phenotype in budding yeast, suggesting a potential role for this domain in DNA replication.
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Affiliation(s)
- Christian Hoffmann
- Free Floater (Junior) Research
Group “Applied Synthetic Biology”, Georg-August University Göttingen, Institute
for Microbiology and Genetics, Justus-von-Liebig
Weg 11, 37077 Göttingen, Germany
| | - Heinz Neumann
- Free Floater (Junior) Research
Group “Applied Synthetic Biology”, Georg-August University Göttingen, Institute
for Microbiology and Genetics, Justus-von-Liebig
Weg 11, 37077 Göttingen, Germany
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18
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Deyter GMR, Biggins S. The FACT complex interacts with the E3 ubiquitin ligase Psh1 to prevent ectopic localization of CENP-A. Genes Dev 2014; 28:1815-26. [PMID: 25128498 PMCID: PMC4197964 DOI: 10.1101/gad.243113.114] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Centromere identity and its epigenetic maintenance require the incorporation of the histone H3 variant CENP-A at centromeres. CENP-A mislocalization may disrupt chromatin-based processes and chromosome segregation. Here, Deyter and Biggins identify a role for the conserved chromatin-modifying complex FACT in preventing CENP-ACse4 mislocalization to euchromatin by mediating its proteolysis. The budding yeast Spt16 subunit of the FACT complex binds to Psh1, an E3 ubiquitin ligase that targets CENP-ACse4 for degradation. A Psh1 mutant that cannot associate with FACT has a reduced interaction with CENP-ACse4 in vivo. Centromere identity and its epigenetic maintenance require the incorporation of a histone H3 variant called CENP-A at centromeres. CENP-A mislocalization to ectopic sites may disrupt chromatin-based processes and chromosome segregation, so it is important to uncover the mechanisms by which this variant is exclusively localized to centromeres. Here, we identify a role for the conserved chromatin-modifying complex FACT (facilitates chromatin transcription/transactions) in preventing budding yeast CENP-ACse4 mislocalization to euchromatin by mediating its proteolysis. The Spt16 subunit of the FACT complex binds to Psh1 (Pob3/Spt16/histone), an E3 ubiquitin ligase that targets CENP-ACse4 for degradation. The interaction between Psh1 and Spt16 is critical for both CENP-ACse4 ubiquitylation and its exclusion from euchromatin. We found that Psh1 cannot efficiently ubiquitylate CENP-ACse4 nucleosomes in vitro, suggesting that additional factors must facilitate CENP-ACse4 removal from chromatin in vivo. Consistent with this, a Psh1 mutant that cannot associate with FACT has a reduced interaction with CENP-ACse4 in vivo. Together, our data identify a previously unknown mechanism to maintain centromere identity and genomic stability through the FACT-mediated degradation of ectopically localized CENP-ACse4.
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Affiliation(s)
- Gary M R Deyter
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | - Sue Biggins
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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19
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Unexpected function of the glucanosyltransferase Gas1 in the DNA damage response linked to histone H3 acetyltransferases in Saccharomyces cerevisiae. Genetics 2014; 196:1029-39. [PMID: 24532730 DOI: 10.1534/genetics.113.158824] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Chromatin organization and structure are crucial for transcriptional regulation, DNA replication, and damage repair. Although initially characterized in remodeling cell wall glucans, the β-1,3-glucanosyltransferase Gas1 was recently discovered to regulate transcriptional silencing in a manner separable from its activity at the cell wall. However, the function of Gas1 in modulating chromatin remains largely unexplored. Our genetic characterization revealed that GAS1 had critical interactions with genes encoding the histone H3 lysine acetyltransferases Gcn5 and Sas3. Specifically, whereas the gas1 gcn5 double mutant was synthetically lethal, deletion of both GAS1 and SAS3 restored silencing in Saccharomyces cerevisiae. The loss of GAS1 also led to broad DNA damage sensitivity with reduced Rad53 phosphorylation and defective cell cycle checkpoint activation following exposure to select genotoxins. Deletion of SAS3 in the gas1 background restored both Rad53 phosphorylation and checkpoint activation following exposure to genotoxins that trigger the DNA replication checkpoint. Our analysis thus uncovers previously unsuspected functions for both Gas1 and Sas3 in DNA damage response and cell cycle regulation.
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20
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Kemble DJ, Whitby FG, Robinson H, McCullough LL, Formosa T, Hill CP. Structure of the Spt16 middle domain reveals functional features of the histone chaperone FACT. J Biol Chem 2013; 288:10188-94. [PMID: 23417676 DOI: 10.1074/jbc.c113.451369] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The histone chaperone FACT is an essential and abundant heterodimer found in all eukaryotes. Here we report a crystal structure of the middle domain of the large subunit of FACT (Spt16-M) to reveal a double pleckstrin homology architecture. This structure was found previously in the Pob3-M domain of the small subunit of FACT and in the related histone chaperone Rtt106, although Spt16-M is distinguished from these structures by the presence of an extended α-helix and a C-terminal addition. Consistent with our finding that the double pleckstrin homology structure is common to these three histone chaperones and reports that Pob3 and Rtt106 double pleckstrin homology domains bind histones H3-H4, we also find that Spt16-M binds H3-H4 with low micromolar affinity. Our structure provides a framework for interpreting a large body of genetic data regarding the physiological functions of FACT, including the identification of potential interaction surfaces for binding histones or other proteins.
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Affiliation(s)
- David J Kemble
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112-5650, USA
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21
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Hainer SJ, Charsar BA, Cohen SB, Martens JA. Identification of Mutant Versions of the Spt16 Histone Chaperone That Are Defective for Transcription-Coupled Nucleosome Occupancy in Saccharomyces cerevisiae. G3 (BETHESDA, MD.) 2012; 2:555-67. [PMID: 22670226 PMCID: PMC3362939 DOI: 10.1534/g3.112.002451] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 03/04/2012] [Indexed: 12/12/2022]
Abstract
The highly conserved FACT (Facilitates Chromatin Transactions) complex performs essential functions in eukaryotic cells through the reorganization of nucleosomes. During transcription, FACT reorganizes nucleosomes to allow passage of RNA Polymerase II and then assists in restoring these nucleosomes after RNA Polymerase II has passed. We have previously shown, consistent with this function, that Spt16 facilitates repression of the Saccharomyces cerevisiae SER3 gene by maintaining nucleosome occupancy over the promoter of this gene as a consequence of intergenic transcription of SRG1 noncoding DNA. In this study, we report the results of a genetic screen to identify mutations in SPT16 that derepress SER3. Twenty-five spt16 mutant alleles were found to derepress SER3 without causing significant reductions in either SRG1 RNA levels or Spt16 protein levels. Additional phenotypic assays indicate that these mutants have general transcription defects related to altered chromatin structure. Our analyses of a subset of these spt16 mutants reveal defects in SRG1 transcription-coupled nucleosome occupancy over the SER3 promoter. We provide evidence that these mutants broadly impair transcription-coupled nucleosome occupancy at highly transcribed genes but not at lowly transcribed genes. Finally, we show that one consequence shared by these mutations is the reduced binding of mutant Spt16 proteins across SRG1 and other highly transcribed genes. Taken together, our results highlight an important role for Spt16 in orchestrating transcription-coupled nucleosome assembly at highly transcribed regions of the genome, possibly by facilitating the association of Spt16 during this process.
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Affiliation(s)
- Sarah J. Hainer
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Brittany A. Charsar
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Shayna B. Cohen
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Joseph A. Martens
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
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22
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Winkler DD, Muthurajan UM, Hieb AR, Luger K. Histone chaperone FACT coordinates nucleosome interaction through multiple synergistic binding events. J Biol Chem 2011; 286:41883-41892. [PMID: 21969370 PMCID: PMC3308894 DOI: 10.1074/jbc.m111.301465] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 09/28/2011] [Indexed: 12/21/2022] Open
Abstract
In eukaryotic cells, DNA maintenance requires ordered disassembly and re-assembly of chromatin templates. These processes are highly regulated and require extrinsic factors such as chromatin remodelers and histone chaperones. The histone chaperone FACT (facilitates chromatin transcription) is a large heterodimeric complex with roles in transcription, replication, and repair. FACT promotes and subsequently restricts access to DNA as a result of dynamic nucleosome reorganization. However, until now, there lacked a truly quantitative assessment of the critical contacts mediating FACT function. Here, we demonstrate that FACT binds histones, DNA, and intact nucleosomes at nanomolar concentrations. We also determine roles for the histone tails in free histone and nucleosome binding by FACT. Furthermore, we propose that the conserved acidic C-terminal domain of the FACT subunit Spt16 actively displaces nucleosomal DNA to provide access to the histone octamer. Experiments with tri-nucleosome arrays indicate a possible mode for FACT binding within chromatin. Together, the data reveal that specific FACT subunits synchronize interactions with various target sites on individual nucleosomes to generate a high affinity binding event and promote reorganization.
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Affiliation(s)
- Duane D Winkler
- Howard Hughes Medical Institute and the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870
| | - Uma M Muthurajan
- Howard Hughes Medical Institute and the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870
| | - Aaron R Hieb
- Howard Hughes Medical Institute and the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870
| | - Karolin Luger
- Howard Hughes Medical Institute and the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870.
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23
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Duina AA. Histone Chaperones Spt6 and FACT: Similarities and Differences in Modes of Action at Transcribed Genes. GENETICS RESEARCH INTERNATIONAL 2011; 2011:625210. [PMID: 22567361 PMCID: PMC3335715 DOI: 10.4061/2011/625210] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 08/16/2011] [Indexed: 01/08/2023]
Abstract
The process of gene transcription requires the participation of a large number of factors that collectively promote the accurate and efficient expression of an organism's genetic information. In eukaryotic cells, a subset of these factors can control the chromatin environments across the regulatory and transcribed units of genes to modulate the transcription process and to ensure that the underlying genetic information is utilized properly. This article focuses on two such factors-the highly conserved histone chaperones Spt6 and FACT-that play critical roles in managing chromatin during the gene transcription process. These factors have related but distinct functions during transcription and several recent studies have provided exciting new insights into their mechanisms of action at transcribed genes. A discussion of their respective roles in regulating gene transcription, including their shared and unique contributions to this process, is presented.
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Affiliation(s)
- Andrea A Duina
- Biology Department, Hendrix College, 1600 Washington Avenue, Conway, AR 72032, USA
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24
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Stevens JR, O'Donnell AF, Perry TE, Benjamin JJR, Barnes CA, Johnston GC, Singer RA. FACT, the Bur kinase pathway, and the histone co-repressor HirC have overlapping nucleosome-related roles in yeast transcription elongation. PLoS One 2011; 6:e25644. [PMID: 22022426 PMCID: PMC3192111 DOI: 10.1371/journal.pone.0025644] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 09/06/2011] [Indexed: 02/03/2023] Open
Abstract
Gene transcription is constrained by the nucleosomal nature of chromosomal DNA. This nucleosomal barrier is modulated by FACT, a conserved histone-binding heterodimer. FACT mediates transcription-linked nucleosome disassembly and also nucleosome reassembly in the wake of the RNA polymerase II transcription complex, and in this way maintains the repression of ‘cryptic’ promoters found within some genes. Here we focus on a novel mutant version of the yeast FACT subunit Spt16 that supplies essential Spt16 activities but impairs transcription-linked nucleosome reassembly in dominant fashion. This Spt16 mutant protein also has genetic effects that are recessive, which we used to show that certain Spt16 activities collaborate with histone acetylation and the activities of a Bur-kinase/Spt4–Spt5/Paf1C pathway that facilitate transcription elongation. These collaborating activities were opposed by the actions of Rpd3S, a histone deacetylase that restores a repressive chromatin environment in a transcription-linked manner. Spt16 activity paralleling that of HirC, a co-repressor of histone gene expression, was also found to be opposed by Rpd3S. Our findings suggest that Spt16, the Bur/Spt4–Spt5/Paf1C pathway, and normal histone abundance and/or stoichiometry, in mutually cooperative fashion, facilitate nucleosome disassembly during transcription elongation. The recessive nature of these effects of the mutant Spt16 protein on transcription-linked nucleosome disassembly, contrasted to its dominant negative effect on transcription-linked nucleosome reassembly, indicate that mutant FACT harbouring the mutant Spt16 protein competes poorly with normal FACT at the stage of transcription-linked nucleosome disassembly, but effectively with normal FACT for transcription-linked nucleosome reassembly. This functional difference is consistent with the idea that FACT association with the transcription elongation complex depends on nucleosome disassembly, and that the same FACT molecule that associates with an elongation complex through nucleosome disassembly is retained for reassembly of the same nucleosome.
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Affiliation(s)
- Jennifer R. Stevens
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Allyson F. O'Donnell
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Troy E. Perry
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jeremy J. R. Benjamin
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Christine A. Barnes
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Gerald C. Johnston
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Richard A. Singer
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
- * E-mail:
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25
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Formosa T. The role of FACT in making and breaking nucleosomes. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1819:247-55. [PMID: 21807128 DOI: 10.1016/j.bbagrm.2011.07.009] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 07/15/2011] [Accepted: 07/16/2011] [Indexed: 12/22/2022]
Abstract
FACT is a roughly 180kDa heterodimeric protein complex important for managing the properties of chromatin in eukaryotic cells. Chromatin is a repressive barrier that plays an important role in protecting genomic DNA and regulating access to it. This barrier must be temporarily removed during transcription, replication, and repair, but it also must be rapidly restored to the original state afterwards. Further, the properties of chromatin are dynamic and must be adjusted as conditions dictate. FACT was identified as a factor that destabilizes nucleosomes in vitro, but it has now also been implicated as a central factor in the deposition of histones to form nucleosomes, as an exchange factor that swaps the histones within existing nucleosomes for variant forms, and as a tether that prevents histones from being displaced by the passage of RNA polymerases during transcription. FACT therefore plays central roles in building, maintaining, adjusting, and overcoming the chromatin barrier. This review summarizes recent results that have begun to reveal how FACT can promote what appear to be contradictory goals, using a simple set of binding activities to both enhance and diminish the stability of nucleosomes. This article is part of a Special Issue entitled: Histone chaperones and Chromatin assembly.
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26
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Abe T, Sugimura K, Hosono Y, Takami Y, Akita M, Yoshimura A, Tada S, Nakayama T, Murofushi H, Okumura K, Takeda S, Horikoshi M, Seki M, Enomoto T. The histone chaperone facilitates chromatin transcription (FACT) protein maintains normal replication fork rates. J Biol Chem 2011; 286:30504-30512. [PMID: 21757688 DOI: 10.1074/jbc.m111.264721] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ordered nucleosome disassembly and reassembly are required for eukaryotic DNA replication. The facilitates chromatin transcription (FACT) complex, a histone chaperone comprising Spt16 and SSRP1, is involved in DNA replication as well as transcription. FACT associates with the MCM helicase, which is involved in DNA replication initiation and elongation. Although the FACT-MCM complex is reported to regulate DNA replication initiation, its functional role in DNA replication elongation remains elusive. To elucidate the functional role of FACT in replication fork progression during DNA elongation in the cells, we generated and analyzed conditional SSRP1 gene knock-out chicken (Gallus gallus) DT40 cells. SSRP1-depleted cells ceased to grow and exhibited a delay in S-phase cell cycle progression, although SSRP1 depletion did not affect the level of chromatin-bound DNA polymerase α or nucleosome reassembly on daughter strands. The tracking length of newly synthesized DNA, but not origin firing, was reduced in SSRP1-depleted cells, suggesting that the S-phase cell cycle delay is mainly due to the inhibition of replication fork progression rather than to defects in the initiation of DNA replication in these cells. We discuss the mechanisms of how FACT promotes replication fork progression in the cells.
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Affiliation(s)
- Takuya Abe
- Molecular Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, Tohoku University, Miyagi 980-8578
| | - Kazuto Sugimura
- Department of Life Science, Graduate School of Bioresources, Mie University, Mie 514-8507; Department of Biochemistry and Proteomics, Graduate School of Medicine, Mie University, Mie 514-8507
| | - Yoshifumi Hosono
- Molecular Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, Tohoku University, Miyagi 980-8578
| | - Yasunari Takami
- Department of Medical Sciences, Section of Biochemistry and Molecular Biology, Miyazaki Medical College, University of Miyazaki, Miyazaki 889-1692
| | - Motomu Akita
- Molecular Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, Tohoku University, Miyagi 980-8578
| | - Akari Yoshimura
- Molecular Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, Tohoku University, Miyagi 980-8578; Research Institute of Pharmaceutical Sciences, Faculty of Pharmacy, Musashino University, Tokyo 202-8585
| | - Shusuke Tada
- Molecular Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, Tohoku University, Miyagi 980-8578
| | - Tatsuo Nakayama
- Department of Medical Sciences, Section of Biochemistry and Molecular Biology, Miyazaki Medical College, University of Miyazaki, Miyazaki 889-1692
| | - Hiromu Murofushi
- Department of Applied Molecular Biosciences, Graduate School of Medicine, Yamaguchi University, Yamaguchi 753-8512
| | - Katsuzumi Okumura
- Department of Life Science, Graduate School of Bioresources, Mie University, Mie 514-8507
| | - Shunichi Takeda
- Department of Radiation Genetics, Faculty of Medicine, Kyoto University, Koyoto 606-8501
| | - Masami Horikoshi
- Laboratory of Developmental Biology, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo 111-0032, Japan.
| | - Masayuki Seki
- Molecular Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, Tohoku University, Miyagi 980-8578.
| | - Takemi Enomoto
- Molecular Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, Tohoku University, Miyagi 980-8578; Research Institute of Pharmaceutical Sciences, Faculty of Pharmacy, Musashino University, Tokyo 202-8585.
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27
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Myers CN, Berner GB, Holthoff JH, Martinez-Fonts K, Harper JA, Alford S, Taylor MN, Duina AA. Mutant versions of the S. cerevisiae transcription elongation factor Spt16 define regions of Spt16 that functionally interact with histone H3. PLoS One 2011; 6:e20847. [PMID: 21673966 PMCID: PMC3108975 DOI: 10.1371/journal.pone.0020847] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 05/09/2011] [Indexed: 11/18/2022] Open
Abstract
In eukaryotic cells, the highly conserved FACT (FAcilitates Chromatin Transcription) complex plays important roles in several chromatin-based processes including transcription initiation and elongation. During transcription elongation, the FACT complex interacts directly with nucleosomes to facilitate histone removal upon RNA polymerase II (Pol II) passage and assists in the reconstitution of nucleosomes following Pol II passage. Although the contribution of the FACT complex to the process of transcription elongation has been well established, the mechanisms that govern interactions between FACT and chromatin still remain to be fully elucidated. Using the budding yeast Saccharomyces cerevisiae as a model system, we provide evidence that the middle domain of the FACT subunit Spt16 – the Spt16-M domain – is involved in functional interactions with histone H3. Our results show that the Spt16-M domain plays a role in the prevention of cryptic intragenic transcription during transcription elongation and also suggest that the Spt16-M domain has a function in regulating dissociation of Spt16 from chromatin at the end of the transcription process. We also provide evidence for a role for the extreme carboxy terminus of Spt16 in functional interactions with histone H3. Taken together, our studies point to previously undescribed roles for the Spt16 M-domain and extreme carboxy terminus in regulating interactions between Spt16 and chromatin during the process of transcription elongation.
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Affiliation(s)
- Catherine N. Myers
- Biology Department, Hendrix College, Conway, Arkansas, United States of America
| | - Gary B. Berner
- Biology Department, Hendrix College, Conway, Arkansas, United States of America
| | - Joseph H. Holthoff
- Biology Department, Hendrix College, Conway, Arkansas, United States of America
| | | | - Jennifer A. Harper
- Biology Department, Hendrix College, Conway, Arkansas, United States of America
| | - Sarah Alford
- Biology Department, Hendrix College, Conway, Arkansas, United States of America
| | - Megan N. Taylor
- Biology Department, Hendrix College, Conway, Arkansas, United States of America
| | - Andrea A. Duina
- Biology Department, Hendrix College, Conway, Arkansas, United States of America
- * E-mail:
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28
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Insight into the mechanism of nucleosome reorganization from histone mutants that suppress defects in the FACT histone chaperone. Genetics 2011; 188:835-46. [PMID: 21625001 DOI: 10.1534/genetics.111.128769] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
FACT (FAcilitates Chromatin Transcription/Transactions) plays a central role in transcription and replication in eukaryotes by both establishing and overcoming the repressive properties of chromatin. FACT promotes these opposing goals by interconverting nucleosomes between the canonical form and a more open reorganized form. In the forward direction, reorganization destabilizes nucleosomes, while the reverse reaction promotes nucleosome assembly. Nucleosome destabilization involves disrupting contacts among histone H2A-H2B dimers, (H3-H4)(2) tetramers, and DNA. Here we show that mutations that weaken the dimer:tetramer interface in nucleosomes suppress defects caused by FACT deficiency in vivo in the yeast Saccharomyces cerevisiae. Mutating the gene that encodes the Spt16 subunit of FACT causes phenotypes associated with defects in transcription and replication, and we identify histone mutants that selectively suppress those associated with replication. Analysis of purified components suggests that the defective version of FACT is unable to maintain the reorganized nucleosome state efficiently, whereas nucleosomes with mutant histones are reorganized more easily than normal. The genetic suppression observed when the FACT defect is combined with the histone defect therefore reveals the importance of the dynamic reorganization of contacts within nucleosomes to the function of FACT in vivo, especially to FACT's apparent role in promoting progression of DNA replication complexes. We also show that an H2B mutation causes different phenotypes, depending on which of the two similar genes that encode this protein are altered, revealing unexpected functional differences between these duplicated genes and calling into question the practice of examining the effects of histone mutants by expressing them from a single plasmid-borne allele.
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29
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Winkler DD, Luger K. The histone chaperone FACT: structural insights and mechanisms for nucleosome reorganization. J Biol Chem 2011; 286:18369-74. [PMID: 21454601 DOI: 10.1074/jbc.r110.180778] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Changes in chromatin architecture induced by epigenetic mechanisms are essential for normal cellular processes such as gene expression, DNA repair, and cellular division. Compact chromatin presents a barrier to these processes and is highly regulated by epigenetic markers binding to components of the nucleosome. Histone modifications directly influence chromatin dynamics and facilitate recruitment of additional factors such as chromatin remodelers and histone chaperones. One member of this last class of factors, FACT (facilitates chromatin transcription), is categorized as a histone chaperone critical for nucleosome reorganization during replication, transcription, and DNA repair. Significant discoveries regarding the role of histone chaperones and specifically FACT have come over the past dozen years from a number of independent laboratories. Here, we review the structural and biophysical basis for FACT-mediated nucleosome reorganization and discuss up-to-date models for FACT function.
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Affiliation(s)
- Duane D Winkler
- Department of Biochemistry and Molecular Biology and the Howard Hughes Medical Institute, Colorado State University, Fort Collins, Colorado 80523-1870, USA
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30
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Kundu LR, Seki M, Watanabe N, Murofushi H, Furukohri A, Waga S, Score AJ, Blow JJ, Horikoshi M, Enomoto T, Tada S. Biphasic chromatin binding of histone chaperone FACT during eukaryotic chromatin DNA replication. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:1129-36. [PMID: 21232560 DOI: 10.1016/j.bbamcr.2011.01.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 12/13/2010] [Accepted: 01/03/2011] [Indexed: 11/17/2022]
Abstract
The facilitates chromatin transcription (FACT) complex affects nuclear DNA transactions in a chromatin context. Though the involvement of FACT in eukaryotic DNA replication has been revealed, a clear understanding of its biochemical behavior during DNA replication still remains elusive. Here, we analyzed the chromatin-binding dynamics of FACT using Xenopus egg extract cell-free system. We found that FACT has at least two distinct chromatin-binding phases: (1) a rapid chromatin-binding phase at the onset of DNA replication that did not involve origin licensing and (2) a second phase of chromatin binding that initiated after origin licensing. Intriguingly, early-binding FACT dissociated from chromatin when DNA replication was blocked by the addition of Cdc6 in the licensed state before origin firing. Cdc6-induced removal of FACT was blocked by the inhibition of origin licensing with geminin, but not by suppressing the activity of DNA polymerases, CDK, or Cdc7. Furthermore, chromatin transfer experiments revealed that impairing the later binding of FACT severely compromises DNA replication activity. Taken together, we propose that even though FACT has rapid chromatin-binding activity, the binding pattern of FACT on chromatin changes after origin licensing, which may contribute to the establishment of its functional link to the DNA replication machinery.
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Affiliation(s)
- Lena R Kundu
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
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31
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Morillo-Huesca M, Maya D, Muñoz-Centeno MC, Singh RK, Oreal V, Reddy GU, Liang D, Géli V, Gunjan A, Chávez S. FACT prevents the accumulation of free histones evicted from transcribed chromatin and a subsequent cell cycle delay in G1. PLoS Genet 2010; 6:e1000964. [PMID: 20502685 PMCID: PMC2873916 DOI: 10.1371/journal.pgen.1000964] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Accepted: 04/20/2010] [Indexed: 11/18/2022] Open
Abstract
The FACT complex participates in chromatin assembly and disassembly during transcription elongation. The yeast mutants affected in the SPT16 gene, which encodes one of the FACT subunits, alter the expression of G1 cyclins and exhibit defects in the G1/S transition. Here we show that the dysfunction of chromatin reassembly factors, like FACT or Spt6, down-regulates the expression of the gene encoding the cyclin that modulates the G1 length (CLN3) in START by specifically triggering the repression of its promoter. The G1 delay undergone by spt16 mutants is not mediated by the DNA–damage checkpoint, although the mutation of RAD53, which is otherwise involved in histone degradation, enhances the cell-cycle defects of spt16-197. We reveal how FACT dysfunction triggers an accumulation of free histones evicted from transcribed chromatin. This accumulation is enhanced in a rad53 background and leads to a delay in G1. Consistently, we show that the overexpression of histones in wild-type cells down-regulates CLN3 in START and causes a delay in G1. Our work shows that chromatin reassembly factors are essential players in controlling the free histones potentially released from transcribed chromatin and describes a new cell cycle phenomenon that allows cells to respond to excess histones before starting DNA replication. Lengthy genomic DNA is packed in a highly organized nucleoprotein structure called chromatin, whose basic subunit is the nucleosome which is formed by DNA wrapped around an octamer of proteins called histones. Nucleosomes need to be disassembled to allow DNA transcription by RNA polymerases. An essential factor for the disassembly/reassembly process during DNA transcription is the FACT complex. We investigated a phenotype of yeast FACT mutants, a delay in a specific step of the cell cycle division process immediately prior to starting DNA replication. The dysfunction caused by the FACT mutation causes a downregulation of a gene, CLN3, which controls the length of that specific step of the cell cycle. FACT dysfunction also increases the level of the free histones released from chromatin during transcription, and the phenotype of the Spt16 mutant is enhanced by a second mutation affecting a protein that regulates DNA repair and excess histone degradation. Moreover, we show that the overexpression of histones causes a cell cycle delay before DNA replication in wild-type cells. Our results point out a so-far unknown connection between chromatin dynamics and the regulation of the cell cycle.
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Affiliation(s)
| | - Douglas Maya
- Departamento de Genética, Universidad de Sevilla, Seville, Spain
| | | | - Rakesh Kumar Singh
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida, United States of America
| | - Vincent Oreal
- Laboratoire d'Instabilité Génétique et Cancérogenèse, Institut de Biologie Struturale et Microbiologie, Centre National de la Recherche Scientifique, Marseille, France
| | - Gajjalaiahvari Ugander Reddy
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida, United States of America
| | - Dun Liang
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida, United States of America
| | - Vincent Géli
- Laboratoire d'Instabilité Génétique et Cancérogenèse, Institut de Biologie Struturale et Microbiologie, Centre National de la Recherche Scientifique, Marseille, France
| | - Akash Gunjan
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida, United States of America
| | - Sebastián Chávez
- Departamento de Genética, Universidad de Sevilla, Seville, Spain
- * E-mail: (SC); (MCM-C)
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32
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The histone shuffle: histone chaperones in an energetic dance. Trends Biochem Sci 2010; 35:476-89. [PMID: 20444609 DOI: 10.1016/j.tibs.2010.04.001] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2010] [Revised: 03/30/2010] [Accepted: 04/05/2010] [Indexed: 11/22/2022]
Abstract
Our genetic information is tightly packaged into a rather ingenious nucleoprotein complex called chromatin in a manner that enables it to be rapidly accessed during genomic processes. Formation of the nucleosome, which is the fundamental unit of chromatin, occurs via a stepwise process that is reversed to enable the disassembly of nucleosomes. Histone chaperone proteins have prominent roles in facilitating these processes as well as in replacing old histones with new canonical histones or histone variants during the process of histone exchange. Recent structural, biophysical and biochemical studies have begun to shed light on the molecular mechanisms whereby histone chaperones promote chromatin assembly, disassembly and histone exchange to facilitate DNA replication, repair and transcription.
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33
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O'Donnell AF, Stevens JR, Kepkay R, Barnes CA, Johnston GC, Singer RA. New mutant versions of yeast FACT subunit Spt16 affect cell integrity. Mol Genet Genomics 2009; 282:487-502. [PMID: 19727824 DOI: 10.1007/s00438-009-0480-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Accepted: 08/20/2009] [Indexed: 11/28/2022]
Abstract
Transcription by RNA polymerase II is impeded by the nucleosomal organization of DNA; these negative effects are modulated at several stages of nucleosomal DNA transcription by FACT, a heterodimeric transcription factor. At promoters, FACT facilitates the binding of TATA-binding factor, while during transcription elongation FACT mediates the necessary destabilization of nucleosomes and subsequent restoration of nucleosome structure in the wake of the transcription elongation complex. Altered FACT activity can impair the fidelity of transcription initiation and affect transcription patterns. Using reporter genes we have identified new mutant versions of the Spt16 subunit of yeast FACT with dominant negative effects on the fidelity of transcription initiation. Two of these spt16 mutant alleles also affect cell integrity. Cells relying on these spt16 mutant alleles display sorbitol-remediated temperature sensitivity, altered sensitivity to detergent, and abnormal morphologies, and are further inhibited by the ssd1-d mutation. The overexpression of components of protein kinase C (Pkc1) signaling diminishes this spt16 ssd1-d temperature sensitivity, whereas gene deletions eliminating components of Pkc1 signaling further impair these spt16 mutant cells. Thus, the FACT subunit Spt16 and Pkc1 signaling have an overlapping essential function, with an unexpected role for FACT in the maintenance of cell integrity.
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Affiliation(s)
- Allyson F O'Donnell
- Department of Biochemistry and Molecular Biology, Dalhousie University, Sir Charles Tupper Medical Building, 5850 College Street, Halifax, NS, B3H 1X5, Canada
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34
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Hanover JA, Love DC, Prinz WA. Calmodulin-driven nuclear entry: trigger for sex determination and terminal differentiation. J Biol Chem 2009; 284:12593-7. [PMID: 19126540 DOI: 10.1074/jbc.r800076200] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We originally proposed that Ca(2+)-calmodulin mediates a novel nuclear entry pathway distinct from the canonic Ran-dependent pathway (Sweitzer, T. D., and Hanover, J. A. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 14574-14579). Although seemingly redundant, Ca(2+)-calmodulin-driven nuclear entry is now known to facilitate nuclear delivery of architectural transcription factors to chromatin. Intriguingly, defects in calmodulin-driven nuclear import of the transcription factors SRY and SOX9 in Sertoli cells lead to human sex reversal diseases with altered male gonad development. Calmodulin-triggered nuclear entry is an evolutionarily ancient feature of eukaryotes observed from yeast to man. Ca(2+)-calmodulin-triggered nuclear entry of key architectural transcription factors is a potentially key epigenetic regulator of terminal differentiation in response to cell signaling.
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Affiliation(s)
- John A Hanover
- Laboratory of Cell Biochemistry and Biology, NIDDK, NIH, Bethesda, MD 20892, USA.
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35
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Abstract
FACT is an essential component of the machinery used by eukaryotic cells both to establish and to overcome the nucleosomal barrier to DNA accessibility, and it does so without hydrolyzing ATP. FACT is a transcription elongation factor, but this review stresses additional roles in DNA replication and initiation of transcription. The widely-held model that FACT functions by displacing an H2A-H2B dimer from a nucleosome is examined, and an alternative proposal is presented in which dimer loss can occur but is a secondary effect of a primary structural change induced by FACT binding which we have called "nucleosome reorganization." The structures of two domains of FACT have been determined and they reveal multiple potential interaction sites. Roles for these binding sites in FACT function and regulation are discussed.
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Affiliation(s)
- Tim Formosa
- University of Utah School of Medicine, Department of Biochemistry, 15 N Medical Drive East RM 4100, Salt Lake City, UT 84112-5650, USA.
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36
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Abstract
The FACT complex is a conserved cofactor for RNA polymerase II elongation through nucleosomes. FACT bears histone chaperone activity and contributes to chromatin integrity. However, the molecular mechanisms behind FACT function remain elusive. Here we report biochemical, structural, and mutational analyses that identify the peptidase homology domain of the Schizosaccharomyces pombe FACT large subunit Spt16 (Spt16-N) as a binding module for histones H3 and H4. The 2.1-A crystal structure of Spt16-N reveals an aminopeptidase P fold whose enzymatic activity has been lost. Instead, the highly conserved fold directly binds histones H3-H4 through a tight interaction with their globular core domains, as well as with their N-terminal tails. Mutations within a conserved surface pocket in Spt16-N or posttranslational modification of the histone H4 tail reduce interaction in vitro, whereas the globular domains of H3-H4 and the H3 tail bind distinct Spt16-N surfaces. Our analysis suggests that the N-terminal domain of Spt16 may add to the known H2A-H2B chaperone activity of FACT by including a H3-H4 tail and H3-H4 core binding function mediated by the N terminus of Spt16. We suggest that these interactions may aid FACT-mediated nucleosome reorganization events.
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37
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A role for Chd1 and Set2 in negatively regulating DNA replication in Saccharomyces cerevisiae. Genetics 2008; 178:649-59. [PMID: 18245327 DOI: 10.1534/genetics.107.084202] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Chromatin-modifying factors regulate both transcription and DNA replication. The yFACT chromatin-reorganizing complex is involved in both processes, and the sensitivity of some yFACT mutants to the replication inhibitor hydroxyurea (HU) is one indication of a replication role. This HU sensitivity can be suppressed by disruptions of the SET2 or CHD1 genes, encoding a histone H3(K36) methyltransferase and a chromatin remodeling factor, respectively. The additive effect of set2 and chd1 mutations in suppressing the HU sensitivity of yFACT mutants suggests that these two factors function in separate pathways. The HU suppression is not an indirect effect of altered regulation of ribonucleotide reductase induced by HU. set2 and chd1 mutations also suppress the HU sensitivity of mutations in other genes involved in DNA replication, including CDC2, CTF4, ORC2, and MEC1. Additionally, a chd1 mutation can suppress the lethality normally caused by disruption of either MEC1 or RAD53 DNA damage checkpoint genes, as well as the lethality seen when a mec1 sml1 mutant is exposed to low levels of HU. The pob3 defect in S-phase progression is suppressed by set2 or chd1 mutations, suggesting that Set2 and Chd1 have specific roles in negatively regulating DNA replication.
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38
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VanDemark AP, Xin H, McCullough L, Rawlins R, Bentley S, Heroux A, Stillman DJ, Hill CP, Formosa T. Structural and functional analysis of the Spt16p N-terminal domain reveals overlapping roles of yFACT subunits. J Biol Chem 2007; 283:5058-68. [PMID: 18089575 DOI: 10.1074/jbc.m708682200] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
yFACT (heterodimers of Saccharomyces cerevisiae Spt16-Pob3 combined with Nhp6) binds to and alters the properties of nucleosomes. The essential function of yFACT is not disrupted by deletion of the N-terminal domain (NTD) of Spt16 or by mutation of the middle domain of Pob3, but either alteration makes yeast cells sensitive to DNA replication stress. We have determined the structure of the Spt16 NTD and find evidence for a conserved potential peptide-binding site. Pob3-M also contains a putative binding site, and we show that these two sites perform an overlapping essential function. We find that yFACT can bind the N-terminal tails of some histones and that this interaction is important for yFACT-nucleosome binding. However, neither the Spt16 NTD nor a key residue in the putative Pob3-M-binding site was required for interactions with histone N termini or for yFACT-mediated nucleosome reorganization in vitro. Instead, both potential binding sites interact functionally with the C-terminal docking domain of the histone H2A. yFACT therefore appears to make multiple contacts with different sites within nucleosomes, and these interactions are partially redundant with one another. The docking domain of H2A is identified as an important participant in maintaining stability during yFACT-mediated nucleosome reorganization, suggesting new models for the mechanism of this activity.
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Affiliation(s)
- Andrew P VanDemark
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA
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39
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Duina AA, Rufiange A, Bracey J, Hall J, Nourani A, Winston F. Evidence that the localization of the elongation factor Spt16 across transcribed genes is dependent upon histone H3 integrity in Saccharomyces cerevisiae. Genetics 2007; 177:101-12. [PMID: 17603125 PMCID: PMC2013732 DOI: 10.1534/genetics.106.067140] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A previous study of histone H3 in Saccharomyces cerevisiae identified a mutant with a single amino acid change, leucine 61 to tryptophan, that confers several transcriptional defects. We now present several lines of evidence that this H3 mutant, H3-L61W, is impaired at the level of transcription elongation, likely by altered interactions with the conserved factor Spt16, a subunit of the transcription elongation complex yFACT. First, a selection for suppressors of the H3-L61W cold-sensitive phenotype has identified novel mutations in the gene encoding Spt16. These genetic interactions are allele specific, suggesting a direct interaction between H3 and Spt16. Second, similar to several other elongation and chromatin mutants, including spt16 mutants, an H3-L61W mutant allows transcription from a cryptic promoter within the FLO8 coding region. Finally, chromatin-immunoprecipitation experiments show that in an H3-L61W mutant there is a dramatically altered profile of Spt16 association over transcribed regions, with reduced levels over 5'-coding regions and elevated levels over the 3' regions. Taken together, these and other results provide strong evidence that the integrity of histone H3 is crucial for ensuring proper distribution of Spt16 across transcribed genes and suggest a model for the mechanism by which Spt16 normally dissociates from DNA following transcription.
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Affiliation(s)
- Andrea A Duina
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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40
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VanDemark AP, Blanksma M, Ferris E, Heroux A, Hill CP, Formosa T. The structure of the yFACT Pob3-M domain, its interaction with the DNA replication factor RPA, and a potential role in nucleosome deposition. Mol Cell 2006; 22:363-74. [PMID: 16678108 DOI: 10.1016/j.molcel.2006.03.025] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2005] [Revised: 01/10/2006] [Accepted: 03/21/2006] [Indexed: 11/30/2022]
Abstract
We report the crystal structure of the middle domain of the Pob3 subunit (Pob3-M) of S. cerevisiae FACT (yFACT, facilitates chromatin transcription), which unexpectedly adopts an unusual double pleckstrin homology (PH) architecture. A mutation within a conserved surface cluster in this domain causes a defect in DNA replication that is suppressed by mutation of replication protein A (RPA). The nucleosome reorganizer yFACT therefore interacts in a physiologically important way with the central single-strand DNA (ssDNA) binding factor RPA to promote a step in DNA replication. Purified yFACT and RPA display a weak direct physical interaction, although the genetic suppression is not explained by simple changes in affinity between the purified proteins. Further genetic analysis suggests that coordinated function by yFACT and RPA is important during nucleosome deposition. These results support the model that the FACT family has an essential role in constructing nucleosomes during DNA replication, and suggest that RPA contributes to this process.
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Affiliation(s)
- Andrew P VanDemark
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, 84132, USA
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41
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Neves-Costa A, Varga-Weisz P. The roles of chromatin remodelling factors in replication. Results Probl Cell Differ 2006; 41:91-107. [PMID: 16909892 DOI: 10.1007/400_007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Dynamic changes of chromatin structure control DNA-dependent events, including DNA replication. Along with DNA, chromatin organization must be replicated to maintain genetic and epigenetic information through cell generations. Chromatin remodelling is important for several steps in replication: determination and activation of origins of replication, replication machinery progression, chromatin assembly and DNA repair. Histone chaperones such as the FACT complex assist DNA replication within chromatin, probably by facilitating both nucleosome disassembly and reassembly. ATP-dependent nucleosome remodelling enzymes of the SWI/SNF family, in particular imitation switch (ISWI)-containing complexes, have been linked to DNA and chromatin replication. They are targeted to replication sites to facilitate DNA replication and subsequent chromatin assembly.
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Current awareness on yeast. Yeast 2005; 22:503-10. [PMID: 15918233 DOI: 10.1002/yea.1162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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