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Hisanaga T, Romani F, Wu S, Kowar T, Wu Y, Lintermann R, Fridrich A, Cho CH, Chaumier T, Jamge B, Montgomery SA, Axelsson E, Akimcheva S, Dierschke T, Bowman JL, Fujiwara T, Hirooka S, Miyagishima SY, Dolan L, Tirichine L, Schubert D, Berger F. The Polycomb repressive complex 2 deposits H3K27me3 and represses transposable elements in a broad range of eukaryotes. Curr Biol 2023; 33:4367-4380.e9. [PMID: 37738971 DOI: 10.1016/j.cub.2023.08.073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 06/19/2023] [Accepted: 08/24/2023] [Indexed: 09/24/2023]
Abstract
The mobility of transposable elements (TEs) contributes to evolution of genomes. Their uncontrolled activity causes genomic instability; therefore, expression of TEs is silenced by host genomes. TEs are marked with DNA and H3K9 methylation, which are associated with silencing in flowering plants, animals, and fungi. However, in distantly related groups of eukaryotes, TEs are marked by H3K27me3 deposited by the Polycomb repressive complex 2 (PRC2), an epigenetic mark associated with gene silencing in flowering plants and animals. The direct silencing of TEs by PRC2 has so far only been shown in one species of ciliates. To test if PRC2 silences TEs in a broader range of eukaryotes, we generated mutants with reduced PRC2 activity and analyzed the role of PRC2 in extant species along the lineage of Archaeplastida and in the diatom P. tricornutum. In this diatom and the red alga C. merolae, a greater proportion of TEs than genes were repressed by PRC2, whereas a greater proportion of genes than TEs were repressed by PRC2 in bryophytes. In flowering plants, TEs contained potential cis-elements recognized by transcription factors and associated with neighbor genes as transcriptional units repressed by PRC2. Thus, silencing of TEs by PRC2 is observed not only in Archaeplastida but also in diatoms and ciliates, suggesting that PRC2 deposited H3K27me3 to silence TEs in the last common ancestor of eukaryotes. We hypothesize that during the evolution of Archaeplastida, TE fragments marked with H3K27me3 were selected to shape transcriptional regulation, controlling networks of genes regulated by PRC2.
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Affiliation(s)
- Tetsuya Hisanaga
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Facundo Romani
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
| | - Shuangyang Wu
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Teresa Kowar
- Epigenetics of Plants, Institute of Biology, Freie Universität Berlin, 14195 Berlin, Germany
| | - Yue Wu
- Nantes Université, CNRS, US2B, UMR 6286, 44000 Nantes, France
| | - Ruth Lintermann
- Epigenetics of Plants, Institute of Biology, Freie Universität Berlin, 14195 Berlin, Germany
| | - Arie Fridrich
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Chung Hyun Cho
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria; Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, South Korea
| | | | - Bhagyshree Jamge
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Sean A Montgomery
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Elin Axelsson
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Svetlana Akimcheva
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Tom Dierschke
- School of Biological Sciences, Monash University, Melbourne, VIC 3800, Australia
| | - John L Bowman
- School of Biological Sciences, Monash University, Melbourne, VIC 3800, Australia; ARC Centre of Excellence for Plant Success in Nature and Agriculture, Monash University, Clayton, Melbourne, VIC 3800, Australia
| | - Takayuki Fujiwara
- Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan; Department of Genetics, Graduate University for Advanced Studies, SOKENDAI, Mishima, Shizuoka 411-8540, Japan
| | - Shunsuke Hirooka
- Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan; Department of Genetics, Graduate University for Advanced Studies, SOKENDAI, Mishima, Shizuoka 411-8540, Japan
| | - Shin-Ya Miyagishima
- Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan; Department of Genetics, Graduate University for Advanced Studies, SOKENDAI, Mishima, Shizuoka 411-8540, Japan
| | - Liam Dolan
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Leila Tirichine
- Nantes Université, CNRS, US2B, UMR 6286, 44000 Nantes, France
| | - Daniel Schubert
- Epigenetics of Plants, Institute of Biology, Freie Universität Berlin, 14195 Berlin, Germany.
| | - Frédéric Berger
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria.
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Jamge B, Lorković ZJ, Axelsson E, Osakabe A, Shukla V, Yelagandula R, Akimcheva S, Kuehn AL, Berger F. Histone variants shape chromatin states in Arabidopsis. eLife 2023; 12:RP87714. [PMID: 37467143 PMCID: PMC10393023 DOI: 10.7554/elife.87714] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023] Open
Abstract
How different intrinsic sequence variations and regulatory modifications of histones combine in nucleosomes remain unclear. To test the importance of histone variants in the organization of chromatin we investigated how histone variants and histone modifications assemble in the Arabidopsis thaliana genome. We showed that a limited number of chromatin states divide euchromatin and heterochromatin into several subdomains. We found that histone variants are as significant as histone modifications in determining the composition of chromatin states. Particularly strong associations were observed between H2A variants and specific combinations of histone modifications. To study the role of H2A variants in organizing chromatin states we determined the role of the chromatin remodeler DECREASED IN DNA METHYLATION (DDM1) in the organization of chromatin states. We showed that the loss of DDM1 prevented the exchange of the histone variant H2A.Z to H2A.W in constitutive heterochromatin, resulting in significant effects on the definition and distribution of chromatin states in and outside of constitutive heterochromatin. We thus propose that dynamic exchanges of histone variants control the organization of histone modifications into chromatin states, acting as molecular landmarks.
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Affiliation(s)
- Bhagyshree Jamge
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenterViennaAustria
- Vienna BioCenterViennaAustria
| | - Zdravko J Lorković
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenterViennaAustria
| | - Elin Axelsson
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenterViennaAustria
| | - Akihisa Osakabe
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenterViennaAustria
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-kuTokyoJapan
- PRESTO, Japan Science and Technology Agency, HonchoKawaguchiJapan
| | - Vikas Shukla
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenterViennaAustria
- Vienna BioCenterViennaAustria
| | - Ramesh Yelagandula
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenterViennaAustria
- Institute of Molecular Biotechnology, IMBA, Dr. Bohr-Gasse 3ViennaAustria
| | - Svetlana Akimcheva
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenterViennaAustria
| | - Annika Luisa Kuehn
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenterViennaAustria
| | - Frédéric Berger
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenterViennaAustria
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Abstract
Our knowledge of the chromatin landscape and its regulation was originally discovered using yeast and a limited number of animals models. A wealth of studies in model plants now strongly demonstrates the conservation of certain features while illuminating the diversification of others. Here we summarize recent advances that describe specific features of chromatin organization of transcriptional units and specific regulation of heterochromatin in flowering plants. We highlight the importance of transcriptional regulation in plant chromatin organization and the need to investigate a more diverse range of species to understand the chromatin landscape in eukaryotes.
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Affiliation(s)
- Bhagyshree Jamge
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr Gasse 3, 1030 Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, A-1030, Vienna, Austria
| | - Frédéric Berger
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr Gasse 3, 1030 Vienna, Austria.
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Naish M, Alonge M, Wlodzimierz P, Tock AJ, Abramson BW, Schmücker A, Mandáková T, Jamge B, Lambing C, Kuo P, Yelina N, Hartwick N, Colt K, Smith LM, Ton J, Kakutani T, Martienssen RA, Schneeberger K, Lysak MA, Berger F, Bousios A, Michael TP, Schatz MC, Henderson IR. The genetic and epigenetic landscape of the Arabidopsis centromeres. Science 2021; 374:eabi7489. [PMID: 34762468 PMCID: PMC10164409 DOI: 10.1126/science.abi7489] [Citation(s) in RCA: 140] [Impact Index Per Article: 46.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Centromeres attach chromosomes to spindle microtubules during cell division and, despite this conserved role, show paradoxically rapid evolution and are typified by complex repeats. We used long-read sequencing to generate the Col-CEN Arabidopsis thaliana genome assembly that resolves all five centromeres. The centromeres consist of megabase-scale tandemly repeated satellite arrays, which support CENTROMERE SPECIFIC HISTONE H3 (CENH3) occupancy and are densely DNA methylated, with satellite variants private to each chromosome. CENH3 preferentially occupies satellites that show the least amount of divergence and occur in higher-order repeats. The centromeres are invaded by ATHILA retrotransposons, which disrupt genetic and epigenetic organization. Centromeric crossover recombination is suppressed, yet low levels of meiotic DNA double-strand breaks occur that are regulated by DNA methylation. We propose that Arabidopsis centromeres are evolving through cycles of satellite homogenization and retrotransposon-driven diversification.
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Affiliation(s)
- Matthew Naish
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Michael Alonge
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA
| | - Piotr Wlodzimierz
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Andrew J. Tock
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Bradley W. Abramson
- The Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Anna Schmücker
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Terezie Mandáková
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, Brno 625 00, Czech Republic
| | - Bhagyshree Jamge
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Christophe Lambing
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Pallas Kuo
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Natasha Yelina
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
| | - Nolan Hartwick
- The Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Kelly Colt
- The Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Lisa M. Smith
- School of Biosciences and Institute for Sustainable Food, University of Sheffield, Sheffield S10 2TN, UK
| | - Jurriaan Ton
- School of Biosciences and Institute for Sustainable Food, University of Sheffield, Sheffield S10 2TN, UK
| | - Tetsuji Kakutani
- Department of Biological Sciences, University of Tokyo, Tokyo, Japan
| | - Robert A. Martienssen
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Korbinian Schneeberger
- Faculty of Biology, LMU Munich, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Martin A. Lysak
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, Brno 625 00, Czech Republic
| | - Frédéric Berger
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | | | - Todd P. Michael
- The Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Michael C. Schatz
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA
| | - Ian R. Henderson
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge CB2 3EA, UK
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Osakabe A, Jamge B, Axelsson E, Montgomery SA, Akimcheva S, Kuehn AL, Pisupati R, Lorković ZJ, Yelagandula R, Kakutani T, Berger F. The chromatin remodeler DDM1 prevents transposon mobility through deposition of histone variant H2A.W. Nat Cell Biol 2021; 23:391-400. [PMID: 33833428 DOI: 10.1038/s41556-021-00658-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 03/01/2021] [Indexed: 12/16/2022]
Abstract
Mobile transposable elements (TEs) not only participate in genome evolution but also threaten genome integrity. In healthy cells, TEs that encode all of the components that are necessary for their mobility are specifically silenced, yet the precise mechanism remains unknown. Here, we characterize the mechanism used by a conserved class of chromatin remodelers that prevent TE mobility. In the Arabidopsis chromatin remodeler DECREASE IN DNA METHYLATION 1 (DDM1), we identify two conserved binding domains for the histone variant H2A.W, which marks plant heterochromatin. DDM1 is necessary and sufficient for the deposition of H2A.W onto potentially mobile TEs, yet does not act on TE fragments or host protein-coding genes. DDM1-mediated H2A.W deposition changes the properties of chromatin, resulting in the silencing of TEs and, therefore, prevents their mobility. This distinct mechanism provides insights into the interplay between TEs and their host in the contexts of evolution and disease, and potentiates innovative strategies for targeted gene silencing.
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Affiliation(s)
- Akihisa Osakabe
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Bhagyshree Jamge
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Elin Axelsson
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Sean A Montgomery
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Svetlana Akimcheva
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Annika Luisa Kuehn
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
- Department of Chromatin Regulation, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Rahul Pisupati
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Zdravko J Lorković
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Ramesh Yelagandula
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
- Institute of Molecular Biotechnology of the Austrian Academy of Science (IMBA), Vienna BioCenter (VBC), Vienna, Austria
| | - Tetsuji Kakutani
- National Institute of Genetics, Mishima, Japan
- Department of Genetics, School of Life science, The Graduate University of Advanced Studies (SOKENDAI), Mishima, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Frédéric Berger
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria.
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Wollmann H, Stroud H, Yelagandula R, Tarutani Y, Jiang D, Jing L, Jamge B, Takeuchi H, Holec S, Nie X, Kakutani T, Jacobsen SE, Berger F. The histone H3 variant H3.3 regulates gene body DNA methylation in Arabidopsis thaliana. Genome Biol 2017; 18:94. [PMID: 28521766 PMCID: PMC5437678 DOI: 10.1186/s13059-017-1221-3] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 04/25/2017] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Gene bodies of vertebrates and flowering plants are occupied by the histone variant H3.3 and DNA methylation. The origin and significance of these profiles remain largely unknown. DNA methylation and H3.3 enrichment profiles over gene bodies are correlated and both have a similar dependence on gene transcription levels. This suggests a mechanistic link between H3.3 and gene body methylation. RESULTS We engineered an H3.3 knockdown in Arabidopsis thaliana and observed transcription reduction that predominantly affects genes responsive to environmental cues. When H3.3 levels are reduced, gene bodies show a loss of DNA methylation correlated with transcription levels. To study the origin of changes in DNA methylation profiles when H3.3 levels are reduced, we examined genome-wide distributions of several histone H3 marks, H2A.Z, and linker histone H1. We report that in the absence of H3.3, H1 distribution increases in gene bodies in a transcription-dependent manner. CONCLUSIONS We propose that H3.3 prevents recruitment of H1, inhibiting H1's promotion of chromatin folding that restricts access to DNA methyltransferases responsible for gene body methylation. Thus, gene body methylation is likely shaped by H3.3 dynamics in conjunction with transcriptional activity.
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Affiliation(s)
- Heike Wollmann
- Temasek Lifesciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore
- Present address: Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore, 138673, Singapore
| | - Hume Stroud
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, CA, 90095, USA
- Howard Hughes Medical Institute, University of California, Los Angeles, CA, 90095, USA
| | - Ramesh Yelagandula
- Gregor Mendel Institute, Vienna Biocenter VBC, Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Yoshiaki Tarutani
- Department of Integrated Genetics, National Institute of Genetics, Shizuoka, 411-8540, Japan
- Department of Genetics, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Shizuoka, 411-8540, Japan
| | - Danhua Jiang
- Gregor Mendel Institute, Vienna Biocenter VBC, Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Li Jing
- Gregor Mendel Institute, Vienna Biocenter VBC, Dr. Bohr-Gasse 3, 1030, Vienna, Austria
- College of Life Science and Technology, Huazhong Agricultural University, No.1, Shizishan Street, Hongshan District Wuhan, Hubei, 430070, China
| | - Bhagyshree Jamge
- Gregor Mendel Institute, Vienna Biocenter VBC, Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Hidenori Takeuchi
- Gregor Mendel Institute, Vienna Biocenter VBC, Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Sarah Holec
- Temasek Lifesciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore
| | - Xin Nie
- Temasek Lifesciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore
| | - Tetsuji Kakutani
- Department of Integrated Genetics, National Institute of Genetics, Shizuoka, 411-8540, Japan
- Department of Genetics, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Shizuoka, 411-8540, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Steven E Jacobsen
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, CA, 90095, USA.
- Howard Hughes Medical Institute, University of California, Los Angeles, CA, 90095, USA.
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA, 90095, USA.
| | - Frédéric Berger
- Gregor Mendel Institute, Vienna Biocenter VBC, Dr. Bohr-Gasse 3, 1030, Vienna, Austria.
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