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Kamata K, Ayano T, Oki M. Spt3 and Spt8 Are Involved in the Formation of a Silencing Boundary by Interacting with TATA-Binding Protein. Biomolecules 2023; 13:biom13040619. [PMID: 37189367 DOI: 10.3390/biom13040619] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/28/2023] [Accepted: 03/28/2023] [Indexed: 03/31/2023] Open
Abstract
In Saccharomyces cerevisiae, a heterochromatin-like chromatin structure called the silencing region is present at the telomere as a complex of Sir2, Sir3, and Sir4. Although spreading of the silencing region is blocked by histone acetylase-mediated boundary formation, the details of the factors and mechanisms involved in the spread and formation of the boundary at each telomere are unknown. Here, we show that Spt3 and Spt8 block the spread of the silencing regions. Spt3 and Spt8 are members of the Spt-Ada-Gcn5-acetyltransferase (SAGA) complex, which has histone acetyltransferase activity. We performed microarray analysis of the transcriptome of spt3Δ and spt8Δ strains and RT-qPCR analysis of the transcript levels of genes from the subtelomeric region in mutants in which the interaction of Spt3 with TATA-binding protein (TBP) is altered. The results not only indicated that both Spt3 and Spt8 are involved in TBP-mediated boundary formation on the right arm of chromosome III, but also that boundary formation in this region is DNA sequence independent. Although both Spt3 and Spt8 interact with TBP, Spt3 had a greater effect on genome-wide transcription. Mutant analysis showed that the interaction between Spt3 and TBP plays an important role in the boundary formation.
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2
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Sun G, Wang C, Wang S, Sun H, Zeng K, Zou R, Lin L, Liu W, Sun N, Song H, Liu W, Zhou T, Jin F, Shan Z, Zhao Y. An H3K4me3 reader, BAP18 as an adaptor of COMPASS-like core subunits co-activates ERα action and associates with the sensitivity of antiestrogen in breast cancer. Nucleic Acids Res 2020; 48:10768-10784. [PMID: 32986841 PMCID: PMC7641737 DOI: 10.1093/nar/gkaa787] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 08/19/2020] [Accepted: 09/10/2020] [Indexed: 12/18/2022] Open
Abstract
Estrogen receptor alpha (ERα) signaling pathway is essential for ERα-positive breast cancer progression and endocrine therapy resistance. Bromodomain PHD Finger Transcription Factor (BPTF) associated protein of 18kDa (BAP18) has been recognized as a crucial H3K4me3 reader. However, the whole genomic occupation of BAP18 and its biological function in breast cancer is still elusive. Here, we found that higher expression of BAP18 in ERα-positive breast cancer is positively correlated with poor prognosis. ChIP-seq analysis further demonstrated that the half estrogen response elements (EREs) and the CCCTC binding factor (CTCF) binding sites are the significant enrichment sites found in estrogen-induced BAP18 binding sites. Also, we provide the evidence to demonstrate that BAP18 as a novel co-activator of ERα is required for the recruitment of COMPASS-like core subunits to the cis-regulatory element of ERα target genes in breast cancer cells. BAP18 is recruited to the promoter regions of estrogen-induced genes, accompanied with the enrichment of the lysine 4-trimethylated histone H3 tail (H3K4me3) in the presence of E2. Furthermore, BAP18 promotes cell growth and associates the sensitivity of antiestrogen in ERα-positive breast cancer. Our data suggest that BAP18 facilitates the association between ERα and COMPASS-like core subunits, which might be an essential epigenetic therapeutic target for breast cancer.
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Affiliation(s)
- Ge Sun
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Sciences, China Medical University, Shenyang City 110122, Liaoning Province, China
| | - Chunyu Wang
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Sciences, China Medical University, Shenyang City 110122, Liaoning Province, China
| | - Shengli Wang
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Sciences, China Medical University, Shenyang City 110122, Liaoning Province, China
| | - Hongmiao Sun
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Sciences, China Medical University, Shenyang City 110122, Liaoning Province, China
| | - Kai Zeng
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Sciences, China Medical University, Shenyang City 110122, Liaoning Province, China
| | - Renlong Zou
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Sciences, China Medical University, Shenyang City 110122, Liaoning Province, China
| | - Lin Lin
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Sciences, China Medical University, Shenyang City 110122, Liaoning Province, China
| | - Wei Liu
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Sciences, China Medical University, Shenyang City 110122, Liaoning Province, China
| | - Ning Sun
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Sciences, China Medical University, Shenyang City 110122, Liaoning Province, China
| | - Huijuan Song
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Sciences, China Medical University, Shenyang City 110122, Liaoning Province, China
| | - Wensu Liu
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Sciences, China Medical University, Shenyang City 110122, Liaoning Province, China
| | - Tingting Zhou
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Sciences, China Medical University, Shenyang City 110122, Liaoning Province, China
| | - Feng Jin
- Department of Breast Surgery, the First Affiliated Hospital of China Medical University, Shenyang City 110001, Liaoning Province, China
| | - Zhongyan Shan
- Department of Endocrinology and Metabolism, Institute of Endocrinology, The First Affiliated Hospital of China Medical University, ShenyangCity110001, Liaoning Province, China
| | - Yue Zhao
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Sciences, China Medical University, Shenyang City 110122, Liaoning Province, China.,Department of Endocrinology and Metabolism, Institute of Endocrinology, The First Affiliated Hospital of China Medical University, ShenyangCity110001, Liaoning Province, China
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3
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Bao K, Shan CM, Moresco J, Yates J, Jia S. Anti-silencing factor Epe1 associates with SAGA to regulate transcription within heterochromatin. Genes Dev 2018; 33:116-126. [PMID: 30573453 PMCID: PMC6317313 DOI: 10.1101/gad.318030.118] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 10/19/2018] [Indexed: 12/11/2022]
Abstract
In this study, Bao et al. investigated how transcription is regulated within heterochromatin in fission yeast. They show that overexpressed Epe1 associates with SAGA and recruits SAGA to heterochromatin regions (which leads to an increase in histone acetylation, transcription of repeats, and the disruption of heterochromatin) and that Epe1 recruits SAGA to regulate transcription within heterochromatin when expressed at normal levels. Heterochromatin is a highly condensed form of chromatin that silences gene transcription. Although high levels of transcriptional activities disrupt heterochromatin, transcription of repetitive DNA elements and subsequent processing of the transcripts by the RNAi machinery are required for heterochromatin assembly. In fission yeast, a JmjC domain protein, Epe1, promotes transcription of DNA repeats to facilitate heterochromatin formation, but overexpression of Epe1 leads to heterochromatin defects. However, the molecular function of Epe1 is not well understood. By screening the fission yeast deletion library, we found that heterochromatin defects associated with Epe1 overexpression are alleviated by mutations of the SAGA histone acetyltransferase complex. Overexpressed Epe1 associates with SAGA and recruits SAGA to heterochromatin regions, which leads to increased histone acetylation, transcription of repeats, and the disruption of heterochromatin. At its normal expression levels, Epe1 also associates with SAGA, albeit weakly. Such interaction regulates histone acetylation levels at heterochromatin and promotes transcription of repeats for heterochromatin assembly. Our results also suggest that increases of certain chromatin protein levels, which frequently occur in cancer cells, might strengthen relatively weak interactions to affect the epigenetic landscape.
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Affiliation(s)
- Kehan Bao
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Chun-Min Shan
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - James Moresco
- Department of Molecular Medicine and Neurobiology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - John Yates
- Department of Molecular Medicine and Neurobiology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Songtao Jia
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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4
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Arras SDM, Ormerod KL, Erpf PE, Espinosa MI, Carpenter AC, Blundell RD, Stowasser SR, Schulz BL, Tanurdzic M, Fraser JA. Convergent microevolution of Cryptococcus neoformans hypervirulence in the laboratory and the clinic. Sci Rep 2017; 7:17918. [PMID: 29263343 PMCID: PMC5738413 DOI: 10.1038/s41598-017-18106-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/05/2017] [Indexed: 12/30/2022] Open
Abstract
Reference strains are a key component of laboratory research, providing a common background allowing for comparisons across a community of researchers. However, laboratory passage of these strains has been shown to lead to reduced fitness and the attenuation of virulence in some species. In this study we show the opposite in the fungal pathogen Cryptococcus neoformans, with analysis of a collection of type strain H99 subcultures revealing that the most commonly used laboratory subcultures belong to a mutant lineage of the type strain that is hypervirulent. The pleiotropic mutant phenotypes in this H99L (for “Laboratory”) lineage are the result of a deletion in the gene encoding the SAGA Associated Factor Sgf29, a mutation that is also present in the widely-used H99L-derived KN99a/α congenic pair. At a molecular level, loss of this gene results in a reduction in histone H3K9 acetylation. Remarkably, analysis of clinical isolates identified loss of function SGF29 mutations in C. neoformans strains infecting two of fourteen patients, demonstrating not only the first example of hypervirulence in clinical C. neoformans samples, but also parallels between in vitro and in vivo microevolution for hypervirulence in this important pathogen.
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Affiliation(s)
- Samantha D M Arras
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Kate L Ormerod
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Paige E Erpf
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Monica I Espinosa
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Alex C Carpenter
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Ross D Blundell
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Samantha R Stowasser
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Benjamin L Schulz
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Milos Tanurdzic
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - James A Fraser
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia. .,School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia.
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5
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Tatsumi K, Sakashita G, Nariai Y, Okazaki K, Kato H, Obayashi E, Yoshida H, Sugiyama K, Park SY, Sekine J, Urano T. G196 epitope tag system: a novel monoclonal antibody, G196, recognizes the small, soluble peptide DLVPR with high affinity. Sci Rep 2017; 7:43480. [PMID: 28266535 PMCID: PMC5339894 DOI: 10.1038/srep43480] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/24/2017] [Indexed: 11/09/2022] Open
Abstract
The recognition specificity of monoclonal antibodies (mAbs) has made mAbs among the most frequently used tools in both basic science research and in clinical diagnosis and therapies. Precise determination of the epitope allows the development of epitope tag systems to be used with recombinant proteins for various purposes. Here we describe a new family of tag derived from the epitope recognized by a highly specific mAb G196. The minimal epitope was identified as the five amino acid sequence Asp-Leu-Val-Pro-Arg. Permutation analysis was used to characterize the binding requirements of mAb G196, and the variable regions of the mAb G196 were identified and structurally analyzed by X-ray crystallography. Isothermal titration calorimetry revealed the high affinity (Kd = 1.25 nM) of the mAb G196/G196-epitope peptide interaction, and G196-tag was used to detect several recombinant cytosolic and nuclear proteins in human and yeast cells. mAb G196 is valuable for developing a new peptide tagging system for cell biology and biochemistry research.
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Affiliation(s)
- Kasumi Tatsumi
- Department of Biochemistry, Shimane University School of Medicine, Izumo 693-8501, Japan.,Department of Oral and Maxillofacial Surgery Shimane University School of Medicine, Izumo 693-8501, Japan
| | - Gyosuke Sakashita
- Department of Biochemistry, Shimane University School of Medicine, Izumo 693-8501, Japan
| | - Yuko Nariai
- Department of Biochemistry, Shimane University School of Medicine, Izumo 693-8501, Japan
| | - Kosuke Okazaki
- Department of Biochemistry, Shimane University School of Medicine, Izumo 693-8501, Japan
| | - Hiroaki Kato
- Department of Biochemistry, Shimane University School of Medicine, Izumo 693-8501, Japan
| | - Eiji Obayashi
- Department of Biochemistry, Shimane University School of Medicine, Izumo 693-8501, Japan
| | - Hisashi Yoshida
- Drug Design Group, Kanagawa Academy of Science and Technology, Kawasaki, Kanagawa, 213-0012, Japan
| | - Kanako Sugiyama
- Drug Design Group, Kanagawa Academy of Science and Technology, Kawasaki, Kanagawa, 213-0012, Japan
| | - Sam-Yong Park
- Drug Design Group, Kanagawa Academy of Science and Technology, Kawasaki, Kanagawa, 213-0012, Japan.,Protein Design Laboratory, Graduate School of Medical Life Science, Yokohama City University, Tsurumi, Yokohama 230-0045, Japan
| | - Joji Sekine
- Department of Oral and Maxillofacial Surgery Shimane University School of Medicine, Izumo 693-8501, Japan
| | - Takeshi Urano
- Department of Biochemistry, Shimane University School of Medicine, Izumo 693-8501, Japan
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6
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Mitsumori R, Shinmyozu K, Nakayama JI, Uchida H, Oki M. Gic1 is a novel heterochromatin boundary protein in vivo. Genes Genet Syst 2016; 91:151-159. [PMID: 27301280 DOI: 10.1266/ggs.15-00070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In Saccharomyces cerevisiae, HMR/HML, telomeres and ribosomal DNA are heterochromatin-like regions in which gene transcription is prevented by the silent information regulator (Sir) complex. The Sir complex (Sir2, Sir3 and Sir4) can spread through chromatin from the silencer. Boundaries prevent Sir complex spreading, and we previously identified 55 boundary genes among all ~6,000 yeast genes. These boundary proteins can be distinguished into two types: those that activate transcription to prevent spreading of silencing, and those that prevent gene silencing by forming a boundary. We selected 44 transcription-independent boundary proteins from the 55 boundary genes by performing a one-hybrid assay and focused on GIC1 (GTPase interaction component 1). Gic1 is an effector of Cdc42, which belongs to the Rho family of small GTPases, and has not been reported to function in heterochromatin boundaries in vivo. We detected a novel boundary-forming activity of Gic1 at HMR-left and telomeric regions by conducting a chromatin immunoprecipitation assay with an anti-Sir3 antibody. We also found that Gic1 bound weakly to histones in two-hybrid analysis. Moreover, we performed domain analysis to identify domain(s) of Gic1 that are important for its boundary activity, and identified two minimum domains, which are located outside its Cdc42-binding domain.
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Affiliation(s)
- Risa Mitsumori
- Department of Applied Chemistry & Biotechnology, Graduate School of Engineering, University of Fukui
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7
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Kamata K, Shinmyozu K, Nakayama JI, Hatashita M, Uchida H, Oki M. Four domains of Ada1 form a heterochromatin boundary through different mechanisms. Genes Cells 2016; 21:1125-1136. [PMID: 27647735 DOI: 10.1111/gtc.12421] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 08/14/2016] [Indexed: 01/21/2023]
Abstract
In eukaryotic cells, there are two chromatin states, silenced and active, and the formation of a so-called boundary plays a critical role in demarcating these regions; however, the mechanisms underlying boundary formation are not well understood. In this study, we focused on S. cerevisiae ADA1, a gene previously shown to encode a protein with a robust boundary function. Ada1 is a component of the histone modification complex Spt-Ada-Gcn5-acetyltransferase (SAGA) and the SAGA-like (SLIK) complex, and it helps to maintain the integrity of these complexes. Domain analysis showed that four relatively small regions of Ada1 (Region I; 66-75 aa, II; 232-282 aa, III; 416-436 aa and IV; 476-488 aa) have a boundary function. Among these, Region II could form an intact SAGA complex, whereas the other regions could not. Investigation of cellular factors that interact with these small regions identified a number of proteasome-associated proteins. Interestingly, the boundary functions of Region II and Region III were affected by depletion of Ump1, a maturation and assembly factor of the 20S proteasome. These results suggest that the boundary function of Ada1 is functionally linked to proteasome processes and that the four relatively small regions in ADA1 form a boundary via different mechanisms.
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Affiliation(s)
- Kazuma Kamata
- Department of Applied Chemistry Biotechnology, Graduate School of Engineering, University of Fukui, Bunkyo, Fukui, Japan.,Research Fellow of the Japan Society for the Promotion of Science, Tokyo, Japan
| | - Kaori Shinmyozu
- Proteomics Support Unit, RIKEN Center for Developmental Biology, Kobe, Japan
| | - Jun-Ichi Nakayama
- Graduate School of Natural Sciences, Nagoya City University, Nagoya, Japan
| | - Masanori Hatashita
- Research and Development Department, Wakasa Wan Energy Research Center, Tsuruga, Japan
| | - Hiroyuki Uchida
- Department of Applied Chemistry Biotechnology, Graduate School of Engineering, University of Fukui, Bunkyo, Fukui, Japan
| | - Masaya Oki
- Department of Applied Chemistry Biotechnology, Graduate School of Engineering, University of Fukui, Bunkyo, Fukui, Japan. .,Life Science Innovation Center, University of Fukui, Bunkyo, Fukui, Japan. .,PRESTO, Japan Science and Technology Agency (JST), Honcho Kawaguchi, Saitama, Japan.
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Mitsumori R, Ohashi T, Kugou K, Ichino A, Taniguchi K, Ohta K, Uchida H, Oki M. Analysis of novel Sir3 binding regions in Saccharomyces cerevisiae. J Biochem 2016; 160:11-7. [PMID: 26957548 DOI: 10.1093/jb/mvw021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Accepted: 12/27/2015] [Indexed: 01/25/2023] Open
Abstract
In Saccharomyces cerevisiae, the HMR, HML, telomere and rDNA regions are silenced. Silencing at the rDNA region requires Sir2, and silencing at the HMR, HML and telomere regions requires binding of a protein complex, consisting of Sir2, Sir3 and Sir4, that mediates repression of gene expression. Here, several novel Sir3 binding domains, termed CN domains (Chromosomal Novel Sir3 binding region), were identified using chromatin immunoprecipitation (ChIP) on chip analysis of S. cerevisiae chromosomes. Furthermore, analysis of G1-arrested cells demonstrated that Sir3 binding was elevated in G1-arrested cells compared with logarithmically growing asynchronous cells, and that Sir3 binding varied with the cell cycle. In addition to 14 CN regions identified from analysis of logarithmically growing asynchronous cells (CN1-14), 11 CN regions were identified from G1-arrested cells (CN15-25). Gene expression at some CN regions did not differ between WT and sir3Δ strains. Sir3 at conventional heterochromatic regions is thought to be recruited to chromosomes by Sir2 and Sir4; however, in this study, Sir3 binding occurred at some CN regions even in sir2Δ and sir4Δ backgrounds. Taken together, our results suggest that Sir3 exhibits novel binding parameters and gene regulatory functions at the CN binding domains.
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Affiliation(s)
- Risa Mitsumori
- Department of Applied Chemistry & Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
| | - Tomoe Ohashi
- Department of Applied Chemistry & Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
| | - Kazuto Kugou
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan; Department of Frontier Research, Kazusa DNA Research Institute, Kisarazu, Chiba 292-0818, Japan
| | - Ayako Ichino
- Department of Applied Chemistry & Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
| | - Kei Taniguchi
- Department of Applied Chemistry & Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
| | - Kunihiro Ohta
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
| | - Hiroyuki Uchida
- Department of Applied Chemistry & Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
| | - Masaya Oki
- Department of Applied Chemistry & Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan; Research and Education Program for Life Science, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan and PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
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9
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Sgf73, a subunit of SAGA complex, is required for the assembly of RITS complex in fission yeast. Sci Rep 2015; 5:14707. [PMID: 26443059 PMCID: PMC4595766 DOI: 10.1038/srep14707] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 09/07/2015] [Indexed: 02/04/2023] Open
Abstract
RNA interference (RNAi) is a widespread gene-silencing mechanism and is required for heterochromatin assembly in a variety of organisms. The RNA-induced transcriptional silencing complex (RITS), composed of Ago1, Tas3 and Chp1, is a key component of RNAi machinery in fission yeast that connects short interference RNA (siRNA) and heterochromatin formation. However, the process by which RITS is assembled is not well understood. Here, we identified Sgf73, a subunit of the SAGA co-transcriptional complex, is required for pericentromeric heterochromatin silencing and the generation of siRNA. This novel role of Sgf73 is independent of enzymatic activities or structural integrity of SAGA. Instead, Sgf73 is physically associated with Ago1 and Chp1. The interactions among the subunits of the RITS, including those between Tas3 and Chp1, between Chp1 and Ago1, between Ago1 and Tas3, were all impaired by the deletion of sgf73+. Consistently, the recruitment of Ago1 and Chp1 to the pericentromeric region was abolished in sgf73Δ cells. Our study unveils a moonlighting function of a SAGA subunit. It suggests Sgf73 is a novel factor that promotes assembly of RITS and RNAi-mediated heterochromatin formation.
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