1
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Xiong Y, Wang T, Wang W, Zhang Y, Zhang F, Yuan J, Qin F, Wang X. Plasma proteome analysis implicates novel proteins as potential therapeutic targets for chronic kidney disease: A proteome-wide association study. Heliyon 2024; 10:e31704. [PMID: 38828357 PMCID: PMC11140797 DOI: 10.1016/j.heliyon.2024.e31704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 05/13/2024] [Accepted: 05/21/2024] [Indexed: 06/05/2024] Open
Abstract
Chronic kidney disease (CKD) is prevalent globally with limited therapeutic drugs available. To systemically identify novel proteins involved in the pathogenesis of CKD and possible therapeutic targets, we integrated human plasma proteomes with the genome-wide association studies (GWASs) of CKD, estimated glomerular filtration rate (eGFR) and blood urea nitrogen (BUN) to perform proteome-wide association study (PWAS), Mendelian Randomization and Bayesian colocalization analyses. The single-cell RNA sequencing data of healthy human and mouse kidneys were analyzed to explore the cell-type specificity of identified genes. Functional enrichment analysis was conducted to investigate the involved signaling pathways. The PWAS identified 22 plasma proteins significantly associated with CKD. Of them, the significant associations of three proteins (INHBC, LMAN2, and SNUPN) were replicated in the GWASs of eGFR, and BUN. Mendelian Randomization analyses showed that INHBC and SNUPN were causally associated with CKD, eGFR, and BUN. The Bayesian colocalization analysis identified shared causal variants for INHBC in CKD, eGFR, and BUN (all PP4 > 0.75). The single-cell RNA sequencing revealed that the INHBC gene was sparsely scattered within the kidney cells. This proteomic study revealed that INHBC, LMAN2, and SNUPN may be involved in the pathogenesis of CKD, which represent novel therapeutic targets and warrant further exploration in future research.
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Affiliation(s)
- Yang Xiong
- Department of Urology and Andrology Laboratory, West China Hospital, Sichuan University, Sichuan, 610041, China
| | - Tianhong Wang
- Department of Anesthesiology, West China Hospital, Sichuan University, Sichuan, 610041, China
| | - Wei Wang
- Department of Urology and Andrology Laboratory, West China Hospital, Sichuan University, Sichuan, 610041, China
| | - Yangchang Zhang
- Department of Public Health, Capital Medical University, Beijing, 100000, China
| | - Fuxun Zhang
- Department of Urology, Tangdu Hospital, The Air Force Medical University, Xi'an, Shaanxi, 710000, China
| | - Jiuhong Yuan
- Department of Urology and Andrology Laboratory, West China Hospital, Sichuan University, Sichuan, 610041, China
| | - Feng Qin
- Department of Urology and Andrology Laboratory, West China Hospital, Sichuan University, Sichuan, 610041, China
| | - Xianding Wang
- Department of Urology and Andrology Laboratory, West China Hospital, Sichuan University, Sichuan, 610041, China
- Kidney Transplant Center, Transplant Center, West China Hospital, Sichuan University, Sichuan, 610041, China
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2
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Tonsager AJ, Zukowski A, Radebaugh CA, Weirich A, Stargell LA, Ramachandran S. THE HISTONE CHAPERONE SPN1 PRESERVES SUBNUCLEOSOMAL STRUCTURES AT PROMOTERS AND NUCLEOSOME POSITIONING IN OPEN READING FRAMES. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.14.585010. [PMID: 38559248 PMCID: PMC10979989 DOI: 10.1101/2024.03.14.585010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Spn1 is a multifunctional histone chaperone essential for life in eukaryotes. While previous work has elucidated regions of the protein important for its many interactions, it is unknown how these domains contribute to the maintenance of chromatin structure. Here, we employ digestion by micrococcal nuclease followed by single-stranded library preparation and sequencing (MNase-SSP) to characterize chromatin structure in yeast expressing wild-type or mutants of Spn1. We mapped nucleosome and subnucleosomal protections genome-wide, and surprisingly, we observed a genome-wide loss of subnucleosomal protection over nucleosome-depleted regions (NDRs) in the Spn1-K192N-containing strain, indicating critical functions of Spn1 in maintaining normal chromatin architecture in promoter regions. Additionally, alterations in nucleosome and hexasome positioning were observed in markedly different mutant Spn1 strains, demonstrating that multiple functions of Spn1 are required to maintain proper chromatin structure in open reading frames, particularly at higher expressed and longer genes. Taken together, our results reveal a previously unknown role of Spn1 in the maintenance of NDR architecture and deepen our understanding of Spn1-dependent chromatin maintenance over transcribed regions.
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Affiliation(s)
- Andrew J. Tonsager
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523-1870, USA
| | | | - Catherine A. Radebaugh
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523-1870, USA
| | | | - Laurie A. Stargell
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523-1870, USA
| | - Srinivas Ramachandran
- Department of Biochemistry and Molecular Genetics
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO, U80045, USA
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3
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Sekine SI, Ehara H, Kujirai T, Kurumizaka H. Structural perspectives on transcription in chromatin. Trends Cell Biol 2024; 34:211-224. [PMID: 37596139 DOI: 10.1016/j.tcb.2023.07.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 07/17/2023] [Accepted: 07/24/2023] [Indexed: 08/20/2023]
Abstract
In eukaryotes, all genetic processes take place in the cell nucleus, where DNA is packaged as chromatin in 'beads-on-a-string' nucleosome arrays. RNA polymerase II (RNAPII) transcribes protein-coding and many non-coding genes in this chromatin environment. RNAPII elongates RNA while passing through multiple nucleosomes and maintaining the integrity of the chromatin structure. Recent structural studies have shed light on the detailed mechanisms of this process, including how transcribing RNAPII progresses through a nucleosome and reassembles it afterwards, and how transcription elongation factors, chromatin remodelers, and histone chaperones participate in these processes. Other studies have also illuminated the crucial role of nucleosomes in preinitiation complex assembly and transcription initiation. In this review we outline these advances and discuss future perspectives.
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Affiliation(s)
- Shun-Ichi Sekine
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.
| | - Haruhiko Ehara
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Tomoya Kujirai
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan; Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Hitoshi Kurumizaka
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan; Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
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4
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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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5
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López-Rivera F, Chuang J, Spatt D, Gopalakrishnan R, Winston F. Suppressor mutations that make the essential transcription factor Spn1/Iws1 dispensable in Saccharomyces cerevisiae. Genetics 2022; 222:iyac125. [PMID: 35977387 PMCID: PMC9526074 DOI: 10.1093/genetics/iyac125] [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: 06/27/2022] [Accepted: 08/11/2022] [Indexed: 11/12/2022] Open
Abstract
Spn1/Iws1 is an essential eukaryotic transcription elongation factor that is conserved from yeast to humans as an integral member of the RNA polymerase II elongation complex. Several studies have shown that Spn1 functions as a histone chaperone to control transcription, RNA splicing, genome stability, and histone modifications. However, the precise role of Spn1 is not understood, and there is little understanding of why it is essential for viability. To address these issues, we have isolated 8 suppressor mutations that bypass the essential requirement for Spn1 in Saccharomyces cerevisiae. Unexpectedly, the suppressors identify several functionally distinct complexes and activities, including the histone chaperone FACT, the histone methyltransferase Set2, the Rpd3S histone deacetylase complex, the histone acetyltransferase Rtt109, the nucleosome remodeler Chd1, and a member of the SAGA coactivator complex, Sgf73. The identification of these distinct groups suggests that there are multiple ways in which Spn1 bypass can occur, including changes in histone acetylation and alterations in other histone chaperones. Thus, Spn1 may function to overcome repressive chromatin by multiple mechanisms during transcription. Our results suggest that bypassing a subset of these functions allows viability in the absence of Spn1.
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Affiliation(s)
| | - James Chuang
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Dan Spatt
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | | | - Fred Winston
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
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6
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Ehara H, Kujirai T, Shirouzu M, Kurumizaka H, Sekine SI. Structural basis of nucleosome disassembly and reassembly by RNAPII elongation complex with FACT. Science 2022; 377:eabp9466. [PMID: 35981082 DOI: 10.1126/science.abp9466] [Citation(s) in RCA: 54] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
During gene transcription, RNA polymerase II (RNAPII) traverses nucleosomes in chromatin, but its mechanism has remained elusive. Using cryo-electron microscopy, we obtained structures of the RNAPII elongation complex (EC) passing through a nucleosome, in the presence of transcription elongation factors Spt6, Spn1, Elf1, Spt4/5, and Paf1C and the histone chaperone FACT. The structures show snapshots of EC progression on DNA, mediating downstream nucleosome disassembly followed by its reassembly upstream of the EC, facilitated by FACT. FACT dynamically adapts to successively occurring subnucleosome intermediates, forming an interface with the EC. Spt6, Spt4/5, and Paf1C form a "cradle" at the EC DNA-exit site, and support the upstream nucleosome reassembly. These structures explain the mechanism by which the EC traverses nucleosomes while maintaining the chromatin structure and epigenetic information.
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Affiliation(s)
- Haruhiko Ehara
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Tomoya Kujirai
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama 230-0045, Japan.,Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Mikako Shirouzu
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Hitoshi Kurumizaka
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama 230-0045, Japan.,Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Shun-Ichi Sekine
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama 230-0045, Japan
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7
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Li S, Edwards G, Radebaugh CA, Luger K, A Stargell L. Spn1 and its dynamic interactions with Spt6, histones and nucleosomes. J Mol Biol 2022; 434:167630. [PMID: 35595162 DOI: 10.1016/j.jmb.2022.167630] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/06/2022] [Accepted: 05/10/2022] [Indexed: 11/25/2022]
Abstract
Histone chaperones facilitate the assembly and disassembly of nucleosomes and regulate DNA accessibility for critical cellular processes. Spn1 is an essential, highly conserved histone chaperone that functions in transcription initiation and elongation in a chromatin context. Here we demonstrate that Spn1 binds H3-H4 with low nanomolar affinity, residues 85-99 within the acidic N-terminal region of Spn1 are required for H3-H4 binding, and Spn1 binding to H3-H4 dimers does not impede (H3-H4)2 tetramer formation. Previous work has shown the central region of Spn1 (residues 141-305) is important for interaction with Spt6, another conserved and essential histone chaperone. We show that the C-terminal region of Spn1 also contributes to Spt6 binding and is critical for Spn1 binding to nucleosomes. We also show Spt6 preferentially binds H3-H4 tetramers and Spt6 competes with nucleosomes for Spn1 binding. Combined with previous results, this indicates the Spn1-Spt6 complex does not bind nucleosomes. In contrast to nucleosome binding, we found that the Spn1-Spt6 complex can bind H3-H4 dimers and tetramers and H2A-H2B to form ternary complexes. These important results provide new information about the functions of Spn1, Spt6, and the Spn1-Spt6 complex, two essential and highly conserved histone chaperones.
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Affiliation(s)
- Sha Li
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523-1870, USA; Department of Biochemistry, University of Colorado, Boulder, CO, 80309, USA
| | - Garrett Edwards
- Department of Biochemistry, University of Colorado, Boulder, CO, 80309, USA
| | - Catherine A Radebaugh
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523-1870, USA
| | - Karolin Luger
- Department of Biochemistry, University of Colorado, Boulder, CO, 80309, USA; Howard Hughes Medical Institute, University of Colorado, Boulder, CO, 80309, USA
| | - Laurie A Stargell
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523-1870, USA
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8
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Edwards GB, Muthurajan UM, Bowerman S, Luger K. Analytical Ultracentrifugation (AUC): An Overview of the Application of Fluorescence and Absorbance AUC to the Study of Biological Macromolecules. ACTA ACUST UNITED AC 2021; 133:e131. [PMID: 33351266 PMCID: PMC7781197 DOI: 10.1002/cpmb.131] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The biochemical and biophysical investigation of proteins, nucleic acids, and the assemblies that they form yields essential information to understand complex systems. Analytical ultracentrifugation (AUC) represents a broadly applicable and information‐rich method for investigating macromolecular characteristics such as size, shape, stoichiometry, and binding properties, all in the true solution‐state environment that is lacking in most orthogonal methods. Despite this, AUC remains underutilized relative to its capabilities and potential in the fields of biochemistry and molecular biology. Although there has been a rapid development of computing power and AUC analysis tools in this millennium, fewer advancements have occurred in development of new applications of the technique, leaving these powerful instruments underappreciated and underused in many research institutes. With AUC previously limited to absorbance and Rayleigh interference optics, the addition of fluorescence detection systems has greatly enhanced the applicability of AUC to macromolecular systems that are traditionally difficult to characterize. This overview provides a resource for novices, highlighting the potential of AUC and encouraging its use in their research, as well as for current users, who may benefit from our experience. We discuss the strengths of fluorescence‐detected AUC and demonstrate the power of even simple AUC experiments to answer practical and fundamental questions about biophysical properties of macromolecular assemblies. We address the development and utility of AUC, explore experimental design considerations, present case studies investigating properties of biological macromolecules that are of common interest to researchers, and review popular analysis approaches. © 2020 The Authors.
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Affiliation(s)
- Garrett B Edwards
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado
| | - Uma M Muthurajan
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado
| | - Samuel Bowerman
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado.,Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado
| | - Karolin Luger
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado.,Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado
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9
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Viktorovskaya O, Chuang J, Jain D, Reim NI, López-Rivera F, Murawska M, Spatt D, Churchman LS, Park PJ, Winston F. Essential histone chaperones collaborate to regulate transcription and chromatin integrity. Genes Dev 2021; 35:698-712. [PMID: 33888559 PMCID: PMC8091981 DOI: 10.1101/gad.348431.121] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 03/30/2021] [Indexed: 12/15/2022]
Abstract
Histone chaperones are critical for controlling chromatin integrity during transcription, DNA replication, and DNA repair. Three conserved and essential chaperones, Spt6, Spn1/Iws1, and FACT, associate with elongating RNA polymerase II and interact with each other physically and/or functionally; however, there is little understanding of their individual functions or their relationships with each other. In this study, we selected for suppressors of a temperature-sensitive spt6 mutation that disrupts the Spt6-Spn1 physical interaction and that also causes both transcription and chromatin defects. This selection identified novel mutations in FACT. Surprisingly, suppression by FACT did not restore the Spt6-Spn1 interaction, based on coimmunoprecipitation, ChIP, and mass spectrometry experiments. Furthermore, suppression by FACT bypassed the complete loss of Spn1. Interestingly, the FACT suppressor mutations cluster along the FACT-nucleosome interface, suggesting that they alter FACT-nucleosome interactions. In agreement with this observation, we showed that the spt6 mutation that disrupts the Spt6-Spn1 interaction caused an elevated level of FACT association with chromatin, while the FACT suppressors reduced the level of FACT-chromatin association, thereby restoring a normal Spt6-FACT balance on chromatin. Taken together, these studies reveal previously unknown regulation between histone chaperones that is critical for their essential in vivo functions.
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Affiliation(s)
- Olga Viktorovskaya
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - James Chuang
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Dhawal Jain
- Department of Biomedical Informatics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Natalia I Reim
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Francheska López-Rivera
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Magdalena Murawska
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Dan Spatt
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - L Stirling Churchman
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Peter J Park
- Department of Biomedical Informatics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Fred Winston
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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10
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Reim NI, Chuang J, Jain D, Alver BH, Park PJ, Winston F. The conserved elongation factor Spn1 is required for normal transcription, histone modifications, and splicing in Saccharomyces cerevisiae. Nucleic Acids Res 2020; 48:10241-10258. [PMID: 32941642 PMCID: PMC7544207 DOI: 10.1093/nar/gkaa745] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/20/2020] [Accepted: 08/27/2020] [Indexed: 12/22/2022] Open
Abstract
Spn1/Iws1 is a conserved protein involved in transcription and chromatin dynamics, yet its general in vivo requirement for these functions is unknown. Using a Spn1 depletion system in Saccharomyces cerevisiae, we demonstrate that Spn1 broadly influences several aspects of gene expression on a genome-wide scale. We show that Spn1 is globally required for normal mRNA levels and for normal splicing of ribosomal protein transcripts. Furthermore, Spn1 maintains the localization of H3K36 and H3K4 methylation across the genome and is required for normal histone levels at highly expressed genes. Finally, we show that the association of Spn1 with the transcription machinery is strongly dependent on its binding partner, Spt6, while the association of Spt6 and Set2 with transcribed regions is partially dependent on Spn1. Taken together, our results show that Spn1 affects multiple aspects of gene expression and provide additional evidence that it functions as a histone chaperone in vivo.
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Affiliation(s)
- Natalia I Reim
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - James Chuang
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Dhawal Jain
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA 02115, USA
| | - Burak H Alver
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA 02115, USA
| | - Peter J Park
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA 02115, USA
| | - Fred Winston
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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11
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Dronamraju R, Kerschner JL, Peck SA, Hepperla AJ, Adams AT, Hughes KD, Aslam S, Yoblinski AR, Davis IJ, Mosley AL, Strahl BD. Casein Kinase II Phosphorylation of Spt6 Enforces Transcriptional Fidelity by Maintaining Spn1-Spt6 Interaction. Cell Rep 2019; 25:3476-3489.e5. [PMID: 30566871 PMCID: PMC6347388 DOI: 10.1016/j.celrep.2018.11.089] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 10/22/2018] [Accepted: 11/21/2018] [Indexed: 02/07/2023] Open
Abstract
Spt6 is a histone chaperone that associates with RNA polymerase II and deposits nucleosomes in the wake of transcription. Although Spt6 has an essential function in nucleosome deposition, it is not known whether this function is influenced by post-translational modification. Here, we report that casein kinase II (CKII) phosphorylation of Spt6 is required for nucleosome occupancy at the 5′ ends of genes to prevent aberrant antisense transcription and enforce transcriptional directionality. Mechanistically, we show that CKII phosphorylation of Spt6 promotes the interaction of Spt6 with Spn1, a binding partner required for chromatin reassembly and full recruitment of Spt6 to genes. Our study defines a function for CKII phosphorylation in transcription and highlights the importance of post-translational modification in histone chaperone function. Dronamraju et al. show that the N terminus of Spt6 is phosphorylated by casein kinase II, which is required for proper Spt6-Spn1 interaction. CKII phosphorylation of Spt6 is pivotal to maintain nucleosome occupancy at the 5′ ends of genes, suppression of antisense transcription from the 5′ ends, and resistance to genotoxic agents.
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Affiliation(s)
- Raghuvar Dronamraju
- Department of Biochemistry & Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Jenny L Kerschner
- Department of Biochemistry & Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Sarah A Peck
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Austin J Hepperla
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Alexander T Adams
- Department of Biochemistry & Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Katlyn D Hughes
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Sadia Aslam
- Department of Biochemistry & Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Andrew R Yoblinski
- Department of Biochemistry & Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Ian J Davis
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA; Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Genetics, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA; Department of Pediatrics, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Amber L Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Brian D Strahl
- Department of Biochemistry & Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA.
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12
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Burriss KH, Mosley AL. Methods review: Mass spectrometry analysis of RNAPII complexes. Methods 2019; 159-160:105-114. [PMID: 30902665 DOI: 10.1016/j.ymeth.2019.03.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/04/2019] [Accepted: 03/17/2019] [Indexed: 12/20/2022] Open
Abstract
RNA Polymerase II (RNAPII) is responsible for transcribing multiple RNA species throughout eukaryotes. A variety of protein-protein interactions occur throughout the transcription cycle for coordinated regulation of transcription initiation, elongation, and/or termination. Taking a proteomics approach to study RNAPII transcription thereby offers a comprehensive view of both RNAPII biology and the variety of proteins that regulate the process itself. This review will focus on how mass spectrometry (MS) methods have expanded understanding of RNAPII and its transcription-regulatory interaction partners. The application of affinity purification mass spectrometry has led to the discovery of a number of novel groups of proteins that regulate an array of RNAPII biology ranging from nuclear import to regulation of phosphorylation state. Additionally, a number of methods have been developed using mass spectrometry to measure protein subunit stoichiometry within and across protein complexes and to perform various types of architectural analysis using structural proteomics approaches. The key methods that we will focus on related to RNAPII mass spectrometry analyses include: affinity purification mass spectrometry, protein post-translational modification analysis, crosslinking mass spectrometry, and native mass spectrometry.
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Affiliation(s)
- Katlyn Hughes Burriss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46402, United States
| | - Amber L Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46402, United States; Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46402, United States.
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Farnung L, Vos SM, Cramer P. Structure of transcribing RNA polymerase II-nucleosome complex. Nat Commun 2018; 9:5432. [PMID: 30575770 PMCID: PMC6303367 DOI: 10.1038/s41467-018-07870-y] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 12/05/2018] [Indexed: 01/08/2023] Open
Abstract
Transcription of eukaryotic protein-coding genes requires passage of RNA polymerase II (Pol II) through nucleosomes, but it is unclear how this is achieved. Here we report the cryo-EM structure of transcribing Saccharomyces cerevisiae Pol II engaged with a downstream nucleosome core particle at an overall resolution of 4.4 Å. Pol II and the nucleosome are observed in a defined relative orientation that is not predicted. Pol II contacts both sides of the nucleosome dyad using its clamp head and lobe domains. Structural comparisons reveal that the elongation factors TFIIS, DSIF, NELF, SPT6, and PAF1 complex can be accommodated on the Pol II surface in the presence of the oriented nucleosome. Our results provide a starting point for analysing the mechanisms of chromatin transcription. Eukaryotic transcription requires passage of RNA polymerase II (Pol II) through chromatin, which is impaired by nucleosomes. Here the authors report the cryo-EM structure of transcribing Pol II engaged with a downstream nucleosome core particle at an overall resolution of 4.4 Å, providing insights into the mechanism of chromatin transcription.
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Affiliation(s)
- Lucas Farnung
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077, Göttingen, Germany
| | - Seychelle M Vos
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077, Göttingen, Germany
| | - Patrick Cramer
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077, Göttingen, Germany.
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Genome Instability Is Promoted by the Chromatin-Binding Protein Spn1 in Saccharomyces cerevisiae. Genetics 2018; 210:1227-1237. [PMID: 30301740 DOI: 10.1534/genetics.118.301600] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 10/02/2018] [Indexed: 02/06/2023] Open
Abstract
Cells expend a large amount of energy to maintain their DNA sequence. DNA repair pathways, cell cycle checkpoint activation, proofreading polymerases, and chromatin structure are ways in which the cell minimizes changes to the genome. During replication, the DNA-damage tolerance pathway allows the replication forks to bypass damage on the template strand. This avoids prolonged replication fork stalling, which can contribute to genome instability. The DNA-damage tolerance pathway includes two subpathways: translesion synthesis and template switch. Post-translational modification of PCNA and the histone tails, cell cycle phase, and local DNA structure have all been shown to influence subpathway choice. Chromatin architecture contributes to maintaining genome stability by providing physical protection of the DNA and by regulating DNA-processing pathways. As such, chromatin-binding factors have been implicated in maintaining genome stability. Using Saccharomyces cerevisiae, we examined the role of Spn1 (Suppresses postrecruitment gene number 1), a chromatin-binding and transcription elongation factor, in DNA-damage tolerance. Expression of a mutant allele of SPN1 results in increased resistance to the DNA-damaging agent methyl methanesulfonate, lower spontaneous and damage-induced mutation rates, along with increased chronological life span. We attribute these effects to an increased usage of the template switch branch of the DNA-damage tolerance pathway in the spn1 strain. This provides evidence for a role of wild-type Spn1 in promoting genome instability, as well as having ties to overcoming replication stress and contributing to chronological aging.
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