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Nakao M, Sato Y, Aizawa A, Kimura H. Mode of SUV420H2 heterochromatin localization through multiple HP1 binding motifs in the heterochromatic targeting module. Genes Cells 2024. [PMID: 38403935 DOI: 10.1111/gtc.13109] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 02/07/2024] [Accepted: 02/08/2024] [Indexed: 02/27/2024]
Abstract
Constitutive heterochromatin is transcriptionally repressed and densely packed chromatin, typically harboring histone H3 Lys9 trimethylation (H3K9me3) and heterochromatin protein 1 (HP1). SUV420H2, a histone H4 Lys20 methyltransferase, is recruited to heterochromatin by binding to HP1 through its Heterochromatic Targeting Module (HTM). Here, we have identified three HP1 binding motifs within the HTM. Both the full-length HTM and its N-terminal region (HTM-N), which contains the first and second motifs, stabilized HP1 on heterochromatin. The intervening region between the first and second HP1 binding motifs in HTM-N was also crucial for HP1 binding. In contrast, the C-terminal region of HTM (HTM-C), containing the third motif, destabilized HP1 on chromatin. An HTM V374D mutant, featuring a Val374 to Asp substitution in the second HP1 binding motif, localizes to heterochromatin without affecting HP1 stability. These data suggest that the second HP1 binding motif in the SUV420H2 HTM is critical for locking HP1 on H3K9me3-enriched heterochromatin. HTM V374D, tagged with a fluorescent protein, can serve as a live-cell probe to visualize HP1-bound heterochromatin.
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Affiliation(s)
- Masaru Nakao
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Yuko Sato
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Arisa Aizawa
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Hiroshi Kimura
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
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2
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Yuan AH, Moazed D. Minimal requirements for the epigenetic inheritance of engineered silent chromatin domains. Proc Natl Acad Sci U S A 2024; 121:e2318455121. [PMID: 38198529 PMCID: PMC10801849 DOI: 10.1073/pnas.2318455121] [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: 10/22/2023] [Accepted: 12/06/2023] [Indexed: 01/12/2024] Open
Abstract
Mechanisms enabling genetically identical cells to differentially regulate gene expression are complex and central to organismal development and evolution. While gene silencing pathways involving DNA sequence-specific recruitment of histone-modifying enzymes are prevalent in nature, examples of sequence-independent heritable gene silencing are scarce. Studies of the fission yeast Schizosaccharomyces pombe indicate that sequence-independent propagation of heterochromatin can occur but requires numerous multisubunit protein complexes and their diverse activities. Such complexity has so far precluded a coherent articulation of the minimal requirements for heritable gene silencing by conventional in vitro reconstitution approaches. Here, we take an unconventional approach to defining these requirements by engineering sequence-independent silent chromatin inheritance in budding yeast Saccharomyces cerevisiae cells. The mechanism conferring memory upon these cells is remarkably simple and requires only two proteins, one that recognizes histone H3 lysine 9 methylation (H3K9me) and catalyzes the deacetylation of histone H4 lysine 16 (H4K16), and another that recognizes deacetylated H4K16 and catalyzes H3K9me. Together, these bilingual "read-write" proteins form an interdependent positive feedback loop that is sufficient for the transmission of DNA sequence-independent silent information over multiple generations.
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Affiliation(s)
- Andy H. Yuan
- HHMI, Harvard Medical School, Boston, MA02115
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA02115
| | - Danesh Moazed
- HHMI, Harvard Medical School, Boston, MA02115
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA02115
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3
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Abstract
The eukaryotic nucleus displays a variety of membraneless compartments with distinct biomolecular composition and specific cellular activities. Emerging evidence indicates that protein-based liquid-liquid phase separation (LLPS) plays an essential role in the formation and dynamic regulation of heterochromatin compartmentalization. This feature is especially conspicuous at the pericentric heterochromatin domains. In this review, we will describe our understanding of heterochromatin organization and LLPS. In addition, we will highlight the increasing importance of multivalent weak homo- and heteromolecular interactions in LLPS-mediated heterochromatin compartmentalization in the complex environment inside living cells.
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Affiliation(s)
- Hui Zhang
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Weihua Qin
- Human Biology and Bioimaging, Faculty of Biology, Ludwig Maximilians University Munich, Planegg-Martinsried, Germany
| | - Hector Romero
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Heinrich Leonhardt
- Human Biology and Bioimaging, Faculty of Biology, Ludwig Maximilians University Munich, Planegg-Martinsried, Germany
| | - M. Cristina Cardoso
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, Darmstadt, Germany,CONTACT M. Cristina Cardoso Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, Schnittspahnstr. 10, 64287Darmstadt, Germany
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Xu K, Li J, Li WX. Simulation of STAT and HP1 interaction by molecular docking. Cell Signal 2023; 112:110925. [PMID: 37839545 DOI: 10.1016/j.cellsig.2023.110925] [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: 07/27/2023] [Revised: 10/06/2023] [Accepted: 10/11/2023] [Indexed: 10/17/2023]
Abstract
Heterochromatin Protein 1 (HP1) is a major component of heterochromatin. Multiple proteins have been shown to interact with HP1 with the HP1-binding motif PxVxL/I, thereby affecting heterochromatin stability. The HP1-interacting proteins include the signal transducer and activator of transcription (STAT) protein, which can be regulated by phosphorylation on a tyrosine around amino acid 700 in the carboxyl terminus. Previous research has shown that unphosphorylated STAT (uSTAT) binds to HP1 via a PxVxI HP1-binding motif and maintains the stability of heterochromatin, while phosphorylated STAT (pSTAT) dissociates from HP1, resulting in heterochromatin disruption. To understand the theoretical basis of the biochemical observations, we employed computational modeling to investigate STAT-HP1 binding configurations and the effect of STAT phosphorylation on their interaction. Using STAT3 and HP1α protein structures for molecular docking and thermodynamic calculations, our computations predict that uSTAT homodimers have a higher affinity for HP1 and a lower affinity for DNA than pSTAT homodimers, and that phosphorylation induces a conformational change in STAT, shifting its binding preference from HP1 to DNA. The results of our modeling studies support the idea that phosphorylation drives STAT from HP1-binding to DNA-binding, suggesting a potential role for uSTAT in both maintaining and initiating heterochromatin formation.
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Affiliation(s)
- Kangxin Xu
- Department of Medicine, University of California San Diego, USA
| | - Jinghong Li
- Department of Medicine, University of California San Diego, USA
| | - Willis X Li
- Department of Medicine, University of California San Diego, USA.
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5
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Abstract
The eukaryotic genome is organized in three dimensions within the nucleus. Transcriptionally active chromatin is spatially separated from silent heterochromatin, a large fraction of which is located at the nuclear periphery. However, the mechanisms by which chromatin is localized at the nuclear periphery remain poorly understood. Here we demonstrate that Proline Rich 14 (PRR14) protein organizes H3K9me3-modified heterochromatin at the nuclear lamina. We show that PRR14 dynamically associates with both the nuclear lamina and heterochromatin, and is able to reorganize heterochromatin in the nucleus of interphase cells independent of mitosis. We characterize two functional HP1-binding sites within PRR14 that contribute to its association with heterochromatin. We also demonstrate that PPR14 forms an anchoring surface for heterochromatin at the nuclear lamina where it interacts dynamically with HP1-associated chromatin. Our study proposes a model of dynamic heterochromatin organization at the nuclear lamina via the PRR14 tethering protein.
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Affiliation(s)
- Anna A. Kiseleva
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yu-Chia Cheng
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Cheryl L. Smith
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Richard A. Katz
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA
| | - Andrey Poleshko
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA,CONTACT Andrey Poleshko Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, SCTR 09-188, 3400 Civic Center Blvd. Philadelphia, PA19104
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Kiseleva AA, Poleshko A. The secret life of chromatin tethers. FEBS Lett 2023; 597:2782-2790. [PMID: 37339933 PMCID: PMC10730768 DOI: 10.1002/1873-3468.14685] [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: 05/10/2023] [Revised: 06/05/2023] [Accepted: 06/12/2023] [Indexed: 06/22/2023]
Abstract
The nuclear envelope plays an essential role in organizing the genome inside of the nucleus. The inner nuclear membrane is coated with a meshwork of filamentous lamin proteins that provide a surface to organize a variety of cellular processes. A subset of nuclear lamina- and membrane-associated proteins functions as anchors to hold transcriptionally silent heterochromatin at the nuclear periphery. While most chromatin tethers are integral membrane proteins, a limited number are lamina-bound. One example is the mammalian proline-rich 14 (PRR14) protein. PRR14 is a recently characterized protein with unique function that is different from other known chromatin tethers. Here, we review our current understanding of PRR14 structure and function in organizing heterochromatin at the nuclear periphery.
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Affiliation(s)
- Anna A. Kiseleva
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Andrey Poleshko
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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7
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Stylianakis E, Chan JPK, Law PP, Jiang Y, Khadayate S, Karimi MM, Festenstein R, Vannier JB. Mouse HP1γ regulates TRF1 expression and telomere stability. Life Sci 2023; 331:122030. [PMID: 37598977 DOI: 10.1016/j.lfs.2023.122030] [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: 11/29/2022] [Revised: 08/16/2023] [Accepted: 08/17/2023] [Indexed: 08/22/2023]
Abstract
AIMS Telomeric repeat-containing RNAs are long non-coding RNAs generated from the telomeres. TERRAs are essential for the establishment of heterochromatin marks at telomeres, which serve for the binding of members of the heterochromatin protein 1 (HP1) protein family of epigenetic modifiers involved with chromatin compaction and gene silencing. While HP1γ is enriched on gene bodies of actively transcribed human and mouse genes, it is unclear if its transcriptional role is important for HP1γ function in telomere cohesion and telomere maintenance. We aimed to study the effect of mouse HP1γ on the transcription of telomere factors and molecules that can affect telomere maintenance. MAIN METHODS We investigated the telomere function of HP1γ by using HP1γ deficient mouse embryonic fibroblasts (MEFs). We used gene expression analysis of HP1γ deficient MEFs and validated the molecular and mechanistic consequences of HP1γ loss by telomere FISH, immunofluorescence, RT-qPCR and DNA-RNA immunoprecipitation (DRIP). KEY FINDINGS Loss of HP1γ in primary MEFs led to a downregulation of various telomere and telomere-accessory transcripts, including the shelterin protein TRF1. Its downregulation is associated with increased telomere replication stress and DNA damage (γH2AX), effects more profound in females. We suggest that the source for the impaired telomere maintenance is a consequence of increased telomeric DNA-RNA hybrids and TERRAs arising at and from mouse chromosomes 18 and X. SIGNIFICANCE Our results suggest an important transcriptional control by mouse HP1γ of various telomere factors including TRF1 protein and TERRAs that has profound consequences on telomere stability, with a potential sexually dimorphic nature.
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Affiliation(s)
- Emmanouil Stylianakis
- Telomere Replication & Stability group, Medical Research Council London Institute of Medical Sciences, London, United Kingdom; Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom; Gene Control Mechanisms and Disease Group, Faculty of Medicine, Department of Brain Sciences, Imperial College London, London, United Kingdom
| | - Jackson Ping Kei Chan
- Gene Control Mechanisms and Disease Group, Faculty of Medicine, Department of Brain Sciences, Imperial College London, London, United Kingdom
| | - Pui Pik Law
- Gene Control Mechanisms and Disease Group, Faculty of Medicine, Department of Brain Sciences, Imperial College London, London, United Kingdom
| | - Yi Jiang
- Gene Control Mechanisms and Disease Group, Faculty of Medicine, Department of Brain Sciences, Imperial College London, London, United Kingdom
| | - Sanjay Khadayate
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Mohammad Mahdi Karimi
- Comprehensive Cancer Centre, School of Cancer & Pharmaceutical Sciences, Faculty of Life Sciences & Medicine, King's College London, London, United Kingdom
| | - Richard Festenstein
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom; Gene Control Mechanisms and Disease Group, Faculty of Medicine, Department of Brain Sciences, Imperial College London, London, United Kingdom
| | - Jean-Baptiste Vannier
- Telomere Replication & Stability group, Medical Research Council London Institute of Medical Sciences, London, United Kingdom; Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom.
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Rahayu AF, Hayashi A, Yoshimura Y, Nakagawa R, Arita K, Nakayama JI. Cooperative DNA-binding activities of Chp2 are critical for its function in heterochromatin assembly. J Biochem 2023; 174:371-382. [PMID: 37400983 DOI: 10.1093/jb/mvad050] [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: 06/13/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 07/05/2023] Open
Abstract
Heterochromatin protein 1 (HP1) is an evolutionarily conserved protein that plays a critical role in heterochromatin assembly. HP1 proteins share a basic structure consisting of an N-terminal chromodomain (CD) and a C-terminal chromoshadow domain (CSD) linked by a disordered hinge region. The CD recognizes histone H3 lysine 9 methylation, a hallmark of heterochromatin, while the CSD forms a dimer to recruit other chromosomal proteins. HP1 proteins have been shown to bind DNA or RNA primarily through the hinge region. However, how DNA or RNA binding contributes to their function remains elusive. Here, we focus on Chp2, one of the two HP1 proteins in fission yeast, and investigate how Chp2's DNA-binding ability contributes to its function. Similar to other HP1 proteins, the Chp2 hinge exhibits clear DNA-binding activity. Interestingly, the Chp2 CSD also shows robust DNA-binding activity. Mutational analysis revealed that basic residues in the Chp2 hinge and at the N-terminus of the CSD are essential for DNA binding, and the combined amino acid substitutions of these residues alter Chp2 stability, impair Chp2 heterochromatin localization and lead to a silencing defect. These results demonstrate that the cooperative DNA-binding activities of Chp2 play an important role in heterochromatin assembly in fission yeast.
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Affiliation(s)
- Anisa Fitri Rahayu
- Division of Chromatin Regulation, National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
- Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies, SOKENDAI, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
| | - Aki Hayashi
- Division of Chromatin Regulation, National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
| | - Yuriko Yoshimura
- Division of Chromatin Regulation, National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
| | - Reiko Nakagawa
- Laboratory for Cell-Free Protein Synthesis, RIKEN Center for Biosystems Dynamics Research, 6-7-1 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Kyohei Arita
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29, Suehiro-cho, Tsurumi-ku, Kanagawa 230-0045, Japan
| | - Jun-Ichi Nakayama
- Division of Chromatin Regulation, National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
- Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies, SOKENDAI, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
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9
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Dong L, Liao H, Zhao L, Wang J, Wang C, Wang B, Sun Y, Xu L, Xia Y, Ling S, Lou X, Qin J. A functional crosstalk between the H3K9 methylation writers and their reader HP1 in safeguarding embryonic stem cell identity. Stem Cell Reports 2023; 18:1775-1792. [PMID: 37703822 PMCID: PMC10545489 DOI: 10.1016/j.stemcr.2023.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 08/07/2023] [Accepted: 08/07/2023] [Indexed: 09/15/2023] Open
Abstract
Histone H3 lysine 9 (H3K9) methylation, as a hallmark of heterochromatin, has a central role in cell lineage and fate determination. Although evidence of a cooperation between H3K9 methylation writers and their readers has started to emerge, their actual interplay remains elusive. Here, we show that loss of H3K9 methylation readers, the Hp1 family, causes reduced expression of H3K9 methyltransferases, and that this subsequently leads to the exit of embryonic stem cells (ESCs) from pluripotency and a reciprocal gain of lineage-specific characteristics. Importantly, the phenotypes of Hp1-null ESCs can be rescued by ectopic expression of Setdb1, Nanog, and Oct4. Furthermore, Setdb1 ablation results in loss of ESC identity, which is accompanied by a reduction in the expression of Hp1 genes. Together, our data support a model in which the safeguarding of ESC identity involves the cooperation between the H3K9 methylation writers and their readers.
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Affiliation(s)
- Lixia Dong
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Medical School of Nanjing University, Nanjing, China
| | - Huaqi Liao
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Medical School of Nanjing University, Nanjing, China
| | - Linchun Zhao
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Medical School of Nanjing University, Nanjing, China
| | - Jingnan Wang
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Medical School of Nanjing University, Nanjing, China
| | - Congcong Wang
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Medical School of Nanjing University, Nanjing, China
| | - Bowen Wang
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Medical School of Nanjing University, Nanjing, China
| | - Yanqi Sun
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Medical School of Nanjing University, Nanjing, China
| | - Lijun Xu
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Medical School of Nanjing University, Nanjing, China
| | - Yin Xia
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Shizhang Ling
- The Translational Research Institute for Neurological Disorders, Department of Neurosurgery, The First Affiliated Hospital (Yijishan Hospital) of Wannan Medical College, Wannan Medical College, Wuhu, China.
| | - Xin Lou
- Research Institute of Intelligent Computing, Zhejiang Lab, Hangzhou 311100, China.
| | - Jinzhong Qin
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Medical School of Nanjing University, Nanjing, China; Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing 210093, China.
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10
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Zhou C, Wu M, Liu G, Zhou L. HP1 induces ferroptosis of renal tubular epithelial cells through NRF2 pathway in diabetic nephropathy. Open Life Sci 2023; 18:20220678. [PMID: 37589000 PMCID: PMC10426721 DOI: 10.1515/biol-2022-0678] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/14/2023] [Accepted: 07/18/2023] [Indexed: 08/18/2023] Open
Abstract
The aim of this study was to investigate the role of ferroptosis in diabetic nephropathy (DN) and the mechanism of its regulatory genes. HK-2 cells were cultured with high glucose and mice were intraperitoneally injected with streptozotocin to establish DN models. GSE111154 was analyzed to identify the abnormal expression of genes associated with DN. Cell injury was evaluated through CCK-8 assay and 4',6-diamidino-2-phenylindole/phenylindole double staining. The levels of iron, glutathione, malondialdehyde, urinary albumin, and urinary creatinine were determined by ELISA. Furthermore, western blot and RT-qPCR were used to detect protein and mRNA levels, respectively. Our data showed that heterochromatin protein 1 is an abnormally elevated gene related to DN and is further elevated by ferroptosis activators. Inhibition of HP1 significantly inhibited ferroptosis but promoted cell viability. In addition, nuclear factor erythroid2-related factor2 (NRF2) was decreased in DN cell model, but increased under the action of ferroptosis activators. NRF2 silencing reversed the protective effects of HP1 inhibition on HK-2 cells. Additionally, HP1 silencing also alleviated kidney damage in DN mice. Collectively, these findings suggest that inhibiting HP1 inhibits ferroptosis via NRF2 pathway, thereby protecting renal tubular epithelial cells from damage.
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Affiliation(s)
- Chuanqiang Zhou
- Department of Nephrology, The First People’s Hospital of Longquanyi District, Chengdu & West China Longquan Hospital, Sichuan University, No. 669, Donglang Road, Longquanyi District, Chengdu, Sichuan Province 610100, China
| | - Min Wu
- Department of Nephrology, The First People’s Hospital of Longquanyi District, Chengdu & West China Longquan Hospital, Sichuan University, No. 669, Donglang Road, Longquanyi District, Chengdu, Sichuan Province 610100, China
| | - Gaolun Liu
- Department of Nephrology, The First People’s Hospital of Longquanyi District, Chengdu & West China Longquan Hospital, Sichuan University, No. 669, Donglang Road, Longquanyi District, Chengdu, Sichuan Province 610100, China
| | - Li Zhou
- Department of Nephrology, West China Hospital, Sichuan University, Chengdu, Sichuan Province 610100, China
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Dupont C, Chahar D, Trullo A, Gostan T, Surcis C, Grimaud C, Fisher D, Feil R, Llères D. Evidence for low nanocompaction of heterochromatin in living embryonic stem cells. EMBO J 2023:e110286. [PMID: 37082862 DOI: 10.15252/embj.2021110286] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/22/2023] [Accepted: 03/29/2023] [Indexed: 04/22/2023] Open
Abstract
Despite advances in the identification of chromatin regulators and genome interactions, the principles of higher-order chromatin structure have remained elusive. Here, we applied FLIM-FRET microscopy to analyse, in living cells, the spatial organisation of nanometre range proximity between nucleosomes, which we called "nanocompaction." Both in naive embryonic stem cells (ESCs) and in ESC-derived epiblast-like cells (EpiLCs), we find that, contrary to expectations, constitutive heterochromatin is much less compacted than bulk chromatin. The opposite was observed in fixed cells. HP1α knockdown increased nanocompaction in living ESCs, but this was overridden by loss of HP1β, indicating the existence of a dynamic HP1-dependent low compaction state in pluripotent cells. Depletion of H4K20me2/3 abrogated nanocompaction, while increased H4K20me3 levels accompanied the nuclear reorganisation during EpiLCs induction. Finally, the knockout of the nuclear cellular-proliferation marker Ki-67 strongly reduced both interphase and mitotic heterochromatin nanocompaction in ESCs. Our data indicate that, contrary to prevailing models, heterochromatin is not highly compacted at the nanoscale but resides in a dynamic low nanocompaction state that depends on H4K20me2/3, the balance between HP1 isoforms, and Ki-67.
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Affiliation(s)
- Claire Dupont
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, Montpellier, France
| | - Dhanvantri Chahar
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, Montpellier, France
| | - Antonio Trullo
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, Montpellier, France
| | - Thierry Gostan
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, Montpellier, France
| | - Caroline Surcis
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, Montpellier, France
| | - Charlotte Grimaud
- Institute of Human Genetics (IGH), CNRS, University of Montpellier, Montpellier, France
| | - Daniel Fisher
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, Montpellier, France
| | - Robert Feil
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, Montpellier, France
| | - David Llères
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, University of Montpellier, Montpellier, France
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12
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Wistner SC, MacDonald IA, Stanley KA, Hathaway NA. Characterization of Hepatoma-Derived Growth Factor-Related Protein 2 Interactions with Heterochromatin. Cells 2023; 12:325. [PMID: 36672260 PMCID: PMC9856275 DOI: 10.3390/cells12020325] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/06/2023] [Accepted: 01/09/2023] [Indexed: 01/18/2023] Open
Abstract
The expression of genetic information is tightly controlled by chromatin regulatory proteins, including those in the heterochromatin gene repression family. Many of these regulatory proteins work together on the chromatin substrate to precisely regulate gene expression during mammalian development, giving rise to many different tissues in higher organisms from a fixed genomic template. Here we identify and characterize the interactions of two related heterochromatin regulatory proteins, heterochromatin protein 1 alpha (HP1α) and M-phase phosphoprotein 8 (MPP8), with hepatoma-derived growth factor-related protein 2 (HRP2). We find in biochemical experiments that HRP2 copurifies and co-sediments with heterochromatin-associated proteins, including HP1α and MPP8. Using the Chromatin in vivo Assay in multiple cell types, we demonstrate that HP1α-mediated gene repression dynamics are altered by the presence of HRP2. Furthermore, the knockout of HRP2 in MDA-MB-231 cells results in significant changes to chromatin structure and stability, which alter gene expression patterns. Here, we detail a mechanism by which HRP2 contributes to epigenetic transcriptional regulation through engagement with heterochromatin-associated proteins to stabilize the chromatin landscape and influence gene expression.
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Affiliation(s)
- Sarah C. Wistner
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ian A. MacDonald
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Karly A. Stanley
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Nathaniel A. Hathaway
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- UNC Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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13
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Mansisidor AR, Risca VI. Chromatin accessibility: methods, mechanisms, and biological insights. Nucleus 2022; 13:236-276. [PMID: 36404679 PMCID: PMC9683059 DOI: 10.1080/19491034.2022.2143106] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [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: 08/31/2022] [Revised: 10/23/2022] [Accepted: 10/30/2022] [Indexed: 11/22/2022] Open
Abstract
Access to DNA is a prerequisite to the execution of essential cellular processes that include transcription, replication, chromosomal segregation, and DNA repair. How the proteins that regulate these processes function in the context of chromatin and its dynamic architectures is an intensive field of study. Over the past decade, genome-wide assays and new imaging approaches have enabled a greater understanding of how access to the genome is regulated by nucleosomes and associated proteins. Additional mechanisms that may control DNA accessibility in vivo include chromatin compaction and phase separation - processes that are beginning to be understood. Here, we review the ongoing development of accessibility measurements, we summarize the different molecular and structural mechanisms that shape the accessibility landscape, and we detail the many important biological functions that are linked to chromatin accessibility.
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Affiliation(s)
- Andrés R. Mansisidor
- Laboratory of Genome Architecture and Dynamics, The Rockefeller University, New York, NY
| | - Viviana I. Risca
- Laboratory of Genome Architecture and Dynamics, The Rockefeller University, New York, NY
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14
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Czerwinska P, Mackiewicz AA. Mining Transcriptomic Data to Uncover the Association between CBX Family Members and Cancer Stemness. Int J Mol Sci 2022; 23. [PMID: 36361869 DOI: 10.3390/ijms232113083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 10/24/2022] [Accepted: 10/25/2022] [Indexed: 12/31/2022] Open
Abstract
Genetic and epigenetic changes might facilitate the acquisition of stem cell-like phenotypes of tumors, resulting in worse patients outcome. Although the role of chromobox (CBX) domain proteins, a family of epigenetic factors that recognize specific histone marks, in the pathogenesis of several tumor types is well documented, little is known about their association with cancer stemness. Here, we have characterized the relationship between the CBX family members' expression and cancer stemness in liver, lung, pancreatic, and uterine tumors using publicly available TCGA and GEO databases and harnessing several bioinformatic tools (i.e., Oncomine, GEPIA2, TISIDB, GSCA, UALCAN, R2 platform, Enrichr, GSEA). We demonstrated that significant upregulation of CBX3 and downregulation of CBX7 are consistently associated with enriched cancer stem-cell-like phenotype across distinct tumor types. High CBX3 expression is observed in higher-grade tumors that exhibit stem cell-like traits, and CBX3-associated gene expression profiles are robustly enriched with stemness markers and targets for c-Myc transcription factor regardless of the tumor type. Similar to high-stemness tumors, CBX3-overexpressing cancers manifest a higher mutation load. On the other hand, higher-grade tumors are characterized by the significant downregulation of CBX7, and CBX7-associated gene expression profiles are significantly depleted with stem cell markers. In contrast to high-stemness tumors, cancer with CBX7 upregulation exhibit a lower mutation burden. Our results clearly demonstrate yet unrecognized association of high CBX3 and low CBX7 expression with cancer stem cell-like phenotype of solid tumors.
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15
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Singh PB, Newman AG. HP1-Driven Micro-Phase Separation of Heterochromatin-Like Domains/Complexes. Epigenet Insights 2022; 15:25168657221109766. [PMID: 35813402 PMCID: PMC9260563 DOI: 10.1177/25168657221109766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 06/08/2022] [Indexed: 11/18/2022] Open
Affiliation(s)
- Prim B Singh
- Department of Medicine, Nazarbayev University School of Medicine, Nur-Sultan, Kazakhstan
| | - Andrew G Newman
- Institute of Cell and Neurobiology, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
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16
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Maeda R, Tachibana M. HP1 maintains protein stability of H3K9 methyltransferases and demethylases. EMBO Rep 2022; 23:e53581. [PMID: 35166421 PMCID: PMC8982598 DOI: 10.15252/embr.202153581] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 01/20/2022] [Accepted: 01/24/2022] [Indexed: 11/09/2022] Open
Abstract
Di- or tri-methylated H3K9 (H3K9me2/3) is an epigenetic mark of heterochromatin. Heterochromatin protein 1 (HP1) specifically recognizes H3K9me2/3, contributing to transcriptional suppression and spread of H3K9me2/3. Here, we demonstrate another role of HP1 in heterochromatin organization: regulation of protein stability of H3K9 methyltransferases (H3K9 MTs) and demethylases (H3K9 DMs). We show that HP1 interaction-defective mutants of H3K9 MTs, Suv39h1 and Setdb1, undergo protein degradation. We further establish mouse embryonic stem cell lines lacking all three HP1 paralogs. In the HP1-deficient cells, Suv39h1, Suv39h2, Setdb1, and G9a/GLP complex decrease at the protein level, and the enzymes are released from chromatin. HP1 mutants that cannot recognize H3K9me2/3 or form dimers cannot stabilize these enzymes, indicating that the tethering of H3K9 MTs to chromatin is critical for their protein stability. We show that HP1 also stabilizes H3K9 DMs, Jmjd1a and Jmjd1b. Our study indicates that mammalian HP1 forms a heterochromatin hub that governs protein stability of H3K9 MTs and H3K9 DMs.
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Affiliation(s)
- Ryo Maeda
- Graduate School of Frontier BiosciencesOsaka UniversityOsakaJapan,Institute of Advanced Medical SciencesTokushima UniversityTokushimaJapan
| | - Makoto Tachibana
- Graduate School of Frontier BiosciencesOsaka UniversityOsakaJapan,Institute of Advanced Medical SciencesTokushima UniversityTokushimaJapan
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17
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Jeon YH, Kim GW, Kim SY, Yi SA, Yoo J, Kim JY, Lee SW, Kwon SH. Heterochromatin Protein 1: A Multiplayer in Cancer Progression. Cancers (Basel) 2022; 14:cancers14030763. [PMID: 35159030 PMCID: PMC8833910 DOI: 10.3390/cancers14030763] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 01/28/2022] [Accepted: 01/29/2022] [Indexed: 11/16/2022] Open
Abstract
Dysregulation of epigenetic mechanisms as well as genomic mutations contribute to the initiation and progression of cancer. In addition to histone code writers, including histone lysine methyltransferase (KMT), and histone code erasers, including histone lysine demethylase (KDM), histone code reader proteins such as HP1 are associated with abnormal chromatin regulation in human diseases. Heterochromatin protein 1 (HP1) recognizes histone H3 lysine 9 methylation and broadly affects chromatin biology, such as heterochromatin formation and maintenance, transcriptional regulation, DNA repair, chromatin remodeling, and chromosomal segregation. Molecular functions of HP1 proteins have been extensively studied, although their exact roles in diseases require further study. Here, we comprehensively review the studies that have revealed the altered expression of HP1 and its functions in tumorigenesis. In particular, the distinctive effects of each HP1 subtype, namely HP1α, HP1β, and HP1γ, have been thoroughly explored in various cancer types. We also highlight how HP1 can serve as a potential biomarker for cancer prognosis and therapeutic target for cancer patients.
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Affiliation(s)
- Yu Hyun Jeon
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon 21983, Korea; (Y.H.J.); (G.W.K.); (S.Y.K.); (J.Y.); (J.Y.K.); (S.W.L.)
| | - Go Woon Kim
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon 21983, Korea; (Y.H.J.); (G.W.K.); (S.Y.K.); (J.Y.); (J.Y.K.); (S.W.L.)
| | - So Yeon Kim
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon 21983, Korea; (Y.H.J.); (G.W.K.); (S.Y.K.); (J.Y.); (J.Y.K.); (S.W.L.)
| | - Sang Ah Yi
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Korea;
| | - Jung Yoo
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon 21983, Korea; (Y.H.J.); (G.W.K.); (S.Y.K.); (J.Y.); (J.Y.K.); (S.W.L.)
| | - Ji Yoon Kim
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon 21983, Korea; (Y.H.J.); (G.W.K.); (S.Y.K.); (J.Y.); (J.Y.K.); (S.W.L.)
| | - Sang Wu Lee
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon 21983, Korea; (Y.H.J.); (G.W.K.); (S.Y.K.); (J.Y.); (J.Y.K.); (S.W.L.)
| | - So Hee Kwon
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon 21983, Korea; (Y.H.J.); (G.W.K.); (S.Y.K.); (J.Y.); (J.Y.K.); (S.W.L.)
- Correspondence: ; Tel.: +82-32-749-4513
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18
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Heath J, Cheyou ES, Findlay S, Luo VM, Carpio EP, Lee J, Djerir B, Chen X, Morin T, Lebeau B, Karam M, Bagci H, Grapton D, Ursini‐Siegel J, Côté J, Witcher M, Richard S, Maréchal A, Orthwein A. POGZ promotes homology-directed DNA repair in an HP1-dependent manner. EMBO Rep 2022; 23:e51041. [PMID: 34758190 PMCID: PMC8728601 DOI: 10.15252/embr.202051041] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 10/08/2021] [Accepted: 10/20/2021] [Indexed: 01/07/2023] Open
Abstract
The heterochromatin protein HP1 plays a central role in the maintenance of genome stability but little is known about how HP1 is controlled. Here, we show that the zinc finger protein POGZ promotes the presence of HP1 at DNA double-strand breaks (DSBs) in human cells. POGZ depletion delays the resolution of DSBs and sensitizes cells to different DNA-damaging agents, including cisplatin and talazoparib. Mechanistically, POGZ promotes homology-directed DNA repair by retaining the BRCA1/BARD1 complex at DSBs in an HP1-dependent manner. In vivo CRISPR inactivation of Pogz is embryonically lethal. Pogz haploinsufficiency (Pogz+ /delta) results in developmental delay, impaired intellectual abilities, hyperactive behaviour and a compromised humoral immune response in mice, recapitulating the main clinical features of the White Sutton syndrome (WHSUS). Pogz+ /delta mice are further radiosensitive and accumulate DSBs in diverse tissues, including the spleen and brain. Altogether, our findings identify POGZ as an important player in homology-directed DNA repair both in vitro and in vivo.
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Affiliation(s)
- John Heath
- Lady Davis Institute for Medical Research, Segal Cancer CentreJewish General HospitalMontrealQCCanada,Division of Experimental MedicineMcGill UniversityMontrealQCCanada
| | - Estelle Simo Cheyou
- Lady Davis Institute for Medical Research, Segal Cancer CentreJewish General HospitalMontrealQCCanada,Gerald Bronfman Department of OncologyMcGill UniversityMontrealQCCanada
| | - Steven Findlay
- Lady Davis Institute for Medical Research, Segal Cancer CentreJewish General HospitalMontrealQCCanada,Division of Experimental MedicineMcGill UniversityMontrealQCCanada
| | - Vincent M Luo
- Lady Davis Institute for Medical Research, Segal Cancer CentreJewish General HospitalMontrealQCCanada,Department of Microbiology and ImmunologyMcGill UniversityMontrealQCCanada
| | - Edgar Pinedo Carpio
- Lady Davis Institute for Medical Research, Segal Cancer CentreJewish General HospitalMontrealQCCanada,Division of Experimental MedicineMcGill UniversityMontrealQCCanada
| | - Jeesan Lee
- Lady Davis Institute for Medical Research, Segal Cancer CentreJewish General HospitalMontrealQCCanada
| | - Billel Djerir
- Department of BiologyUniversité de SherbrookeSherbrookeQCCanada
| | - Xiaoru Chen
- Lady Davis Institute for Medical Research, Segal Cancer CentreJewish General HospitalMontrealQCCanada
| | - Théo Morin
- Department of BiologyUniversité de SherbrookeSherbrookeQCCanada
| | - Benjamin Lebeau
- Lady Davis Institute for Medical Research, Segal Cancer CentreJewish General HospitalMontrealQCCanada,Division of Experimental MedicineMcGill UniversityMontrealQCCanada
| | - Martin Karam
- Lady Davis Institute for Medical Research, Segal Cancer CentreJewish General HospitalMontrealQCCanada,Division of Experimental MedicineMcGill UniversityMontrealQCCanada
| | - Halil Bagci
- Institut de Recherches Cliniques de Montréal (IRCM)MontrealQCCanada,Département of Anatomy and Cell BiologyMcGill UniversityMontrealQCCanada,Present address:
Institute of BiochemistryETH ZürichZürichSwitzerland
| | - Damien Grapton
- Lady Davis Institute for Medical Research, Segal Cancer CentreJewish General HospitalMontrealQCCanada
| | - Josie Ursini‐Siegel
- Lady Davis Institute for Medical Research, Segal Cancer CentreJewish General HospitalMontrealQCCanada,Division of Experimental MedicineMcGill UniversityMontrealQCCanada,Gerald Bronfman Department of OncologyMcGill UniversityMontrealQCCanada
| | - Jean‐Francois Côté
- Institut de Recherches Cliniques de Montréal (IRCM)MontrealQCCanada,Département of Anatomy and Cell BiologyMcGill UniversityMontrealQCCanada,Département de Biochimie et Médecine MoléculaireUniversité de MontréalMontrealQCCanada,Département de Médecine (Programmes de Biologie Moléculaire)Université de MontréalMontrealQCCanada
| | - Michael Witcher
- Lady Davis Institute for Medical Research, Segal Cancer CentreJewish General HospitalMontrealQCCanada,Division of Experimental MedicineMcGill UniversityMontrealQCCanada
| | - Stéphane Richard
- Lady Davis Institute for Medical Research, Segal Cancer CentreJewish General HospitalMontrealQCCanada,Gerald Bronfman Department of OncologyMcGill UniversityMontrealQCCanada
| | | | - Alexandre Orthwein
- Lady Davis Institute for Medical Research, Segal Cancer CentreJewish General HospitalMontrealQCCanada,Division of Experimental MedicineMcGill UniversityMontrealQCCanada,Gerald Bronfman Department of OncologyMcGill UniversityMontrealQCCanada,Department of Microbiology and ImmunologyMcGill UniversityMontrealQCCanada
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19
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Ilyin AA, Stolyarenko AD, Zenkin N, Klenov MS. Complex Genetic Interactions between Piwi and HP1a in the Repression of Transposable Elements and Tissue-Specific Genes in the Ovarian Germline. Int J Mol Sci 2021; 22:13430. [PMID: 34948223 DOI: 10.3390/ijms222413430] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/03/2021] [Accepted: 12/10/2021] [Indexed: 11/16/2022] Open
Abstract
Insertions of transposable elements (TEs) in eukaryotic genomes are usually associated with repressive chromatin, which spreads to neighbouring genomic sequences. In ovaries of Drosophila melanogaster, the Piwi-piRNA pathway plays a key role in the transcriptional silencing of TEs considered to be exerted mostly through the establishment of H3K9me3 histone marks recruiting Heterochromatin Protein 1a (HP1a). Here, using RNA-seq, we investigated the expression of TEs and the adjacent genomic regions upon Piwi and HP1a germline knockdowns sharing a similar genetic background. We found that the depletion of Piwi and HP1a led to the derepression of only partially overlapping TE sets. Several TEs were silenced predominantly by HP1a, whereas the upregulation of some other TEs was more pronounced upon Piwi knockdown and, surprisingly, was diminished upon a Piwi/HP1a double-knockdown. We revealed that HP1a loss influenced the expression of thousands of protein-coding genes mostly not adjacent to TE insertions and, in particular, downregulated a putative transcriptional factor required for TE activation. Nevertheless, our results indicate that Piwi and HP1a cooperatively exert repressive effects on the transcription of euchromatic loci flanking the insertions of some Piwi-regulated TEs. We suggest that this mechanism controls the silencing of a small set of TE-adjacent tissue-specific genes, preventing their inappropriate expression in ovaries.
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20
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Gao Y, Han M, Shang S, Wang H, Qi LS. Interrogation of the dynamic properties of higher-order heterochromatin using CRISPR-dCas9. Mol Cell 2021; 81:4287-4299.e5. [PMID: 34428454 PMCID: PMC8541924 DOI: 10.1016/j.molcel.2021.07.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [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: 06/09/2020] [Revised: 05/27/2021] [Accepted: 07/28/2021] [Indexed: 12/12/2022]
Abstract
Eukaryotic chromosomes feature large regions of compact, repressed heterochromatin hallmarked by Heterochromatin Protein 1 (HP1). HP1 proteins play multi-faceted roles in shaping heterochromatin, and in cells, HP1 tethering to individual gene promoters leads to epigenetic modifications and silencing. However, emergent properties of HP1 at supranucleosomal scales remain difficult to study in cells because of a lack of appropriate tools. Here, we develop CRISPR-engineered chromatin organization (EChO), combining live-cell CRISPR imaging with inducible large-scale recruitment of chromatin proteins to native genomic targets. We demonstrate that human HP1α tiled across kilobase-scale genomic DNA form novel contacts with natural heterochromatin, integrates two distantly targeted regions, and reversibly changes chromatin from a diffuse to compact state. The compact state exhibits delayed disassembly kinetics and represses transcription across over 600 kb. These findings support a polymer model of HP1α-mediated chromatin regulation and highlight the utility of CRISPR-EChO in studying supranucleosomal chromatin organization in living cells.
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Affiliation(s)
- Yuchen Gao
- Cancer Biology Program, Stanford University, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Mengting Han
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Stephen Shang
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Haifeng Wang
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Lei S Qi
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA; ChEM-H, Stanford University, Stanford, CA 94305, USA.
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21
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Zykova T, Maltseva M, Goncharov F, Boldyreva L, Pokholkova G, Kolesnikova T, Zhimulev I. The Organization of Pericentromeric Heterochromatin in Polytene Chromosome 3 of the Drosophilamelanogaster Line with the Rif11; SuURES Su(var)3-906 Mutations Suppressing Underreplication. Cells 2021; 10:2809. [PMID: 34831030 DOI: 10.3390/cells10112809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/11/2021] [Accepted: 10/14/2021] [Indexed: 11/17/2022] Open
Abstract
Although heterochromatin makes up 40% of the Drosophila melanogaster genome, its organization remains little explored, especially in polytene chromosomes, as it is virtually not represented in them due to underreplication. Two all-new approaches were used in this work: (i) with the use of a newly synthesized Drosophila line that carries three mutations, Rif11, SuURES and Su(var)3-906, suppressing the underreplication of heterochromatic regions, we obtained their fullest representation in polytene chromosomes and described their structure; (ii) 20 DNA fragments with known positions on the physical map as well as molecular genetic features of the genome (gene density, histone marks, heterochromatin proteins, origin recognition complex proteins, replication timing sites and satellite DNAs) were mapped in the newly polytenized heterochromatin using FISH and bioinformatics data. The borders of the heterochromatic regions and variations in their positions on arm 3L have been determined for the first time. The newly polytenized heterochromatic material exhibits two main types of morphology: a banding pattern (locations of genes and short satellites) and reticular chromatin (locations of large blocks of satellite DNA). The locations of the banding and reticular polytene heterochromatin was determined on the physical map.
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22
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Napoletano F, Ferrari Bravo G, Voto IAP, Santin A, Celora L, Campaner E, Dezi C, Bertossi A, Valentino E, Santorsola M, Rustighi A, Fajner V, Maspero E, Ansaloni F, Cancila V, Valenti CF, Santo M, Artimagnella OB, Finaurini S, Gioia U, Polo S, Sanges R, Tripodo C, Mallamaci A, Gustincich S, d'Adda di Fagagna F, Mantovani F, Specchia V, Del Sal G. The prolyl-isomerase PIN1 is essential for nuclear Lamin-B structure and function and protects heterochromatin under mechanical stress. Cell Rep 2021; 36:109694. [PMID: 34525372 DOI: 10.1016/j.celrep.2021.109694] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 06/29/2021] [Accepted: 08/19/2021] [Indexed: 01/24/2023] Open
Abstract
Chromatin organization plays a crucial role in tissue homeostasis. Heterochromatin relaxation and consequent unscheduled mobilization of transposable elements (TEs) are emerging as key contributors of aging and aging-related pathologies, including Alzheimer's disease (AD) and cancer. However, the mechanisms governing heterochromatin maintenance or its relaxation in pathological conditions remain poorly understood. Here we show that PIN1, the only phosphorylation-specific cis/trans prolyl isomerase, whose loss is associated with premature aging and AD, is essential to preserve heterochromatin. We demonstrate that this PIN1 function is conserved from Drosophila to humans and prevents TE mobilization-dependent neurodegeneration and cognitive defects. Mechanistically, PIN1 maintains nuclear type-B Lamin structure and anchoring function for heterochromatin protein 1α (HP1α). This mechanism prevents nuclear envelope alterations and heterochromatin relaxation under mechanical stress, which is a key contributor to aging-related pathologies.
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Affiliation(s)
- Francesco Napoletano
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy; Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy.
| | - Gloria Ferrari Bravo
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy; Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy
| | - Ilaria Anna Pia Voto
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy
| | - Aurora Santin
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy
| | - Lucia Celora
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy
| | - Elena Campaner
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy; Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy
| | - Clara Dezi
- Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy
| | - Arianna Bertossi
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy; Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy
| | - Elena Valentino
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy
| | - Mariangela Santorsola
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy; Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy
| | - Alessandra Rustighi
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy; Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy
| | | | - Elena Maspero
- FIRC Institute of Molecular Oncology (IFOM), 20139 Milan, Italy
| | - Federico Ansaloni
- Area of Neuroscience, International School for Advanced Studies (SISSA), 34146 Trieste, Italy
| | - Valeria Cancila
- Tumor Immunology Unit, Department of Health Science, Human Pathology Section, School of Medicine, University of Palermo, 90133 Palermo, Italy
| | - Cesare Fabio Valenti
- Tumor Immunology Unit, Department of Health Science, Human Pathology Section, School of Medicine, University of Palermo, 90133 Palermo, Italy
| | - Manuela Santo
- Area of Neuroscience, International School for Advanced Studies (SISSA), 34146 Trieste, Italy
| | | | - Sara Finaurini
- Area of Neuroscience, International School for Advanced Studies (SISSA), 34146 Trieste, Italy
| | - Ubaldo Gioia
- FIRC Institute of Molecular Oncology (IFOM), 20139 Milan, Italy
| | - Simona Polo
- FIRC Institute of Molecular Oncology (IFOM), 20139 Milan, Italy
| | - Remo Sanges
- Area of Neuroscience, International School for Advanced Studies (SISSA), 34146 Trieste, Italy
| | - Claudio Tripodo
- FIRC Institute of Molecular Oncology (IFOM), 20139 Milan, Italy; Tumor Immunology Unit, Department of Health Science, Human Pathology Section, School of Medicine, University of Palermo, 90133 Palermo, Italy
| | - Antonello Mallamaci
- Area of Neuroscience, International School for Advanced Studies (SISSA), 34146 Trieste, Italy
| | - Stefano Gustincich
- Area of Neuroscience, International School for Advanced Studies (SISSA), 34146 Trieste, Italy; Central RNA Laboratory, Italian Institute of Technology, 16163 Genova, Italy
| | - Fabrizio d'Adda di Fagagna
- FIRC Institute of Molecular Oncology (IFOM), 20139 Milan, Italy; Institute of Molecular Genetics, National Research Institute (CNR), Pavia, Italy
| | - Fiamma Mantovani
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy; Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy
| | - Valeria Specchia
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), University of Salento, 73100 Lecce, Italy
| | - Giannino Del Sal
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy; Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy; FIRC Institute of Molecular Oncology (IFOM), 20139 Milan, Italy.
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Takahata S, Chida S, Ohnuma A, Ando M, Asanuma T, Murakami Y. Two secured FACT recruitment mechanisms are essential for heterochromatin maintenance. Cell Rep 2021; 36:109540. [PMID: 34407404 DOI: 10.1016/j.celrep.2021.109540] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 04/01/2021] [Accepted: 07/26/2021] [Indexed: 11/18/2022] Open
Abstract
FACT (facilitate chromatin transcription) is involved in heterochromatic silencing, but its mechanisms and function remain unclear. We reveal that the Spt16 recruitment mechanism operates in two distinct ways in heterochromatin. First, Pob3 mediates Spt16 recruitment onto the heterochromatin through its Spt16 dimerization and tandem PH domains. Without Pob3, Spt16 recruitment is partially reduced, exhibiting a silencing defect and impaired H2A/H2B organization. Second, heterochromatin protein 1 (HP1)/Swi6 mediates Spt16 recruitment onto the heterochromatin by physical interaction of the Swi6 chromo-shadow domain (CSD) and Spt16 peptidase-like domains. Several CSD mutants are tested for Spt16 binding activity, and the charged loop connecting β1 and β2 is critical for Spt16 binding and heterochromatic silencing. Loss of these pathways causes a severe defect in H3K9 methylation and HP1/Swi6 localization in the pericentromeric region, exhibiting transcriptional silencing defects and disordered heterochromatin. Our findings suggest that FACT and HP1/Swi6 work intimately to regulate heterochromatin organization.
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Affiliation(s)
- Shinya Takahata
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan.
| | - Saori Chida
- Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Aoi Ohnuma
- Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Motoyoshi Ando
- Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Takahiro Asanuma
- Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Yota Murakami
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
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24
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Rachez C, Legendre R, Costallat M, Varet H, Yi J, Kornobis E, Muchardt C. HP1γ binding pre-mRNA intronic repeats modulates RNA splicing decisions. EMBO Rep 2021; 22:e52320. [PMID: 34312949 DOI: 10.15252/embr.202052320] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 06/17/2021] [Accepted: 06/22/2021] [Indexed: 12/30/2022] Open
Abstract
HP1 proteins are best known as markers of heterochromatin and gene silencing. Yet, they are also RNA-binding proteins and the HP1γ/CBX3 family member is present on transcribed genes together with RNA polymerase II, where it regulates co-transcriptional processes such as alternative splicing. To gain insight in the role of the RNA-binding activity of HP1γ in transcriptionally active chromatin, we have captured and analysed RNAs associated with this protein. We find that HP1γ is specifically targeted to hexameric RNA motifs and coincidentally transposable elements of the SINE family. As these elements are abundant in introns, while essentially absent from exons, the HP1γ RNA association tethers unspliced pre-mRNA to chromatin via the intronic regions and limits the usage of intronic cryptic splice sites. Thus, our data unveil novel determinants in the relationship between chromatin and co-transcriptional splicing.
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Affiliation(s)
- Christophe Rachez
- Institut de Biologie Paris-Seine, Sorbonne Université, Paris, France.,CNRS UMR 8256, Biological Adaptation and Aging, Paris, France.,Epigenetic Regulation Unit, Institut Pasteur, CNRS UMR 3738, Paris, France
| | - Rachel Legendre
- Bioinformatics and Biostatistics Hub, Department of Computational Biology, Institut Pasteur, USR 3756 CNRS, Paris, France.,Biomics Technological Platform, Center for Technological Resources and Research, Institut Pasteur, Paris, France
| | - Mickaël Costallat
- Institut de Biologie Paris-Seine, Sorbonne Université, Paris, France.,CNRS UMR 8256, Biological Adaptation and Aging, Paris, France.,Epigenetic Regulation Unit, Institut Pasteur, CNRS UMR 3738, Paris, France
| | - Hugo Varet
- Bioinformatics and Biostatistics Hub, Department of Computational Biology, Institut Pasteur, USR 3756 CNRS, Paris, France.,Biomics Technological Platform, Center for Technological Resources and Research, Institut Pasteur, Paris, France
| | - Jia Yi
- Epigenetic Regulation Unit, Institut Pasteur, CNRS UMR 3738, Paris, France.,Sorbonne Université, Ecole Doctorale Complexité du Vivant (ED515), Paris, France
| | - Etienne Kornobis
- Epigenetic Regulation Unit, Institut Pasteur, CNRS UMR 3738, Paris, France
| | - Christian Muchardt
- Institut de Biologie Paris-Seine, Sorbonne Université, Paris, France.,CNRS UMR 8256, Biological Adaptation and Aging, Paris, France.,Epigenetic Regulation Unit, Institut Pasteur, CNRS UMR 3738, Paris, France
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25
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Ramirez Moreno M, Stempor PA, Bulgakova NA. Interactions and Feedbacks in E-Cadherin Transcriptional Regulation. Front Cell Dev Biol 2021; 9:701175. [PMID: 34262912 PMCID: PMC8273600 DOI: 10.3389/fcell.2021.701175] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 06/04/2021] [Indexed: 01/07/2023] Open
Abstract
Epithelial tissues rely on the adhesion between participating cells to retain their integrity. The transmembrane protein E-cadherin is the major protein that mediates homophilic adhesion between neighbouring cells and is, therefore, one of the critical components for epithelial integrity. E-cadherin downregulation has been described extensively as a prerequisite for epithelial-to-mesenchymal transition and is a hallmark in many types of cancer. Due to this clinical importance, research has been mostly focused on understanding the mechanisms leading to transcriptional repression of this adhesion molecule. However, in recent years it has become apparent that re-expression of E-cadherin is a major step in the progression of many cancers during metastasis. Here, we review the currently known molecular mechanisms of E-cadherin transcriptional activation and inhibition and highlight complex interactions between individual mechanisms. We then propose an additional mechanism, whereby the competition between adhesion complexes and heterochromatin protein-1 for binding to STAT92E fine-tunes the levels of E-cadherin expression in Drosophila but also regulates other genes promoting epithelial robustness. We base our hypothesis on both existing literature and our experimental evidence and suggest that such feedback between the cell surface and the nucleus presents a powerful paradigm for epithelial resilience.
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Affiliation(s)
- Miguel Ramirez Moreno
- Department of Biomedical Science and Bateson Centre, The University of Sheffield, Sheffield, England
| | | | - Natalia A Bulgakova
- Department of Biomedical Science and Bateson Centre, The University of Sheffield, Sheffield, England
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26
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Suetake I, Nakazawa S, Sato K, Mutoh R, Mishima Y, Kawakami T, Takei T, Watanabe M, Sakai N, Fujiwara T, Takui T, Miyata M, Shinohara A, Hojo H, Arata T. Structural dynamics of the chromo-shadow domain and chromodomain of HP1 bound to histone H3K9 methylated peptide, as measured by site-directed spin-labeling EPR spectroscopy. Biochem Biophys Res Commun 2021; 567:42-48. [PMID: 34139556 DOI: 10.1016/j.bbrc.2021.06.010] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 06/03/2021] [Indexed: 10/21/2022]
Abstract
The structural dynamics of the chromo-shadow domain (CSD) and chromodomain (CD) of human HP1 proteins essential for heterochromatin formation were investigated at the nanosecond and nanometer scales by site-directed spin labeling electron paramagnetic resonance and pulsed double resonance spectroscopy. Distance measurements showed that the spin-labeled CSD of human HP1α and HP1γ tightly dimerizes. Unlike CD-CD interaction observed in fission yeast HP1 in an inactivated state (Canzio et al., 2013), the two CDs of HP1α and HP1γ were spatially separated from each other, dynamically mobile, and ready for a Brownian search for H3K9-tri-methyl(me3) on histones. Complex formation of the CD with H3K9me3 slowed dynamics of the domain due to a decreased diffusion constant. CSD mobility was significantly (∼1.3-fold) lower in full-length HP1α than in HP1γ, suggesting that the immobilized conformation of human HP1α shows an auto-inactivated state. Differential properties of HP1α and HP1γ to form the inactive conformation could be relevant to its physiological role in the heterochromatin formation in a cell.
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Affiliation(s)
- Isao Suetake
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan; Center for Twin Research, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan; Department of Nutritional Sciences, Graduate School of Nutritional Sciences, Nakamura Gakuen University, Fukuoka, 814-0198, Japan.
| | - Shigeaki Nakazawa
- Department of Chemistry and Molecular Materials Sciences, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Kazunobu Sato
- Department of Chemistry and Molecular Materials Sciences, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Risa Mutoh
- Department of Applied Physics, Faculty of Science, Fukuoka University, Fukuoka, 814-0180, Japan
| | - Yuichi Mishima
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
| | - Toru Kawakami
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
| | - Toshiki Takei
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
| | - Mikio Watanabe
- Center for Twin Research, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
| | - Norio Sakai
- Center for Twin Research, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
| | | | - Takeji Takui
- Department of Chemistry and Molecular Materials Sciences, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Makoto Miyata
- Department of Biology, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Akira Shinohara
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
| | - Hironobu Hojo
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
| | - Toshiaki Arata
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan; Department of Biology, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan.
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27
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Bui HTN, Passecker A, Brancucci NMB, Voss TS. Investigation of Heterochromatin Protein 1 Function in the Malaria Parasite Plasmodium falciparum Using a Conditional Domain Deletion and Swapping Approach. mSphere 2021; 6:e01220-20. [PMID: 33536327 DOI: 10.1128/mSphere.01220-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Malaria is caused by unicellular Plasmodium species parasites that repeatedly invade and replicate inside red blood cells. Some blood-stage parasites exit the cell cycle and differentiate into gametocytes that are essential for malaria transmission via the mosquito vector. The human malaria parasite Plasmodium falciparum encodes a single ortholog of heterochromatin protein 1 (PfHP1) that plays a crucial role in the epigenetic regulation of various survival-related processes. PfHP1 is essential for parasite proliferation and the heritable silencing of genes linked to antigenic variation, host cell invasion, and sexual conversion. Here, we employed CRISPR/Cas9-mediated genome editing combined with the DiCre/loxP system to investigate how the PfHP1 chromodomain (CD), hinge domain, and chromoshadow domain (CSD) contribute to overall PfHP1 function. We show that the 76 C-terminal residues are responsible for targeting PfHP1 to the nucleus. Furthermore, we reveal that each of the three functional domains of PfHP1 are required for heterochromatin formation, gene silencing, and mitotic parasite proliferation. Finally, we discovered that the hinge domain and CSD of HP1 are functionally conserved between P. falciparum and P. berghei, a related malaria parasite infecting rodents. In summary, our study provides new insights into PfHP1 function and offers a tool for further studies on epigenetic regulation and life cycle decision in malaria parasites. IMPORTANCE Malaria is caused by unicellular Plasmodium species parasites that repeatedly invade and replicate inside red blood cells. Some blood-stage parasites exit the cell cycle and differentiate into gametocytes that are essential for malaria transmission via the mosquito vector. Epigenetic control mechanisms allow the parasites to alter the expression of surface antigens and to balance the switch between parasite multiplication and gametocyte production. These processes are crucial to establish chronic infection and optimize parasite transmission. Here, we performed a mutational analysis of heterochromatin protein 1 (HP1) in P. falciparum. We demonstrate that all three domains of this protein are indispensable for the proper function of HP1 in parasite multiplication, heterochromatin formation, and gene silencing. Moreover, expression of chimeric proteins revealed the functional conservation of HP1 proteins between different Plasmodium species. These results provide new insight into the function and evolution of HP1 as an essential epigenetic regulator of parasite survival.
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Fesquet D, Llères D, Grimaud C, Viganò C, Méchali F, Boulon S, Coux O, Bonne-Andrea C, Baldin V. The 20S proteasome activator PA28γ controls the compaction of chromatin. J Cell Sci 2021; 134:134/3/jcs257717. [PMID: 33526472 DOI: 10.1242/jcs.257717] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 12/03/2020] [Indexed: 12/16/2022] Open
Abstract
PA28γ (also known as PSME3), a nuclear activator of the 20S proteasome, is involved in the degradation of several proteins regulating cell growth and proliferation and in the dynamics of various nuclear bodies, but its precise cellular functions remain unclear. Here, using a quantitative FLIM-FRET based microscopy assay monitoring close proximity between nucleosomes in living human cells, we show that PA28γ controls chromatin compaction. We find that its depletion induces a decompaction of pericentromeric heterochromatin, which is similar to what is observed upon the knockdown of HP1β (also known as CBX1), a key factor of the heterochromatin structure. We show that PA28γ is present at HP1β-containing repetitive DNA sequences abundant in heterochromatin and, importantly, that HP1β on its own is unable to drive chromatin compaction without the presence of PA28γ. At the molecular level, we show that this novel function of PA28γ is independent of its stable interaction with the 20S proteasome, and most likely depends on its ability to maintain appropriate levels of H3K9me3 and H4K20me3, histone modifications that are involved in heterochromatin formation. Overall, our results implicate PA28γ as a key factor involved in the regulation of the higher order structure of chromatin.
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Affiliation(s)
- Didier Fesquet
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, 34293 Montpellier, France
| | - David Llères
- Institut de Génétique Moléculaire de Montpellier (IGMM), Université de Montpellier, CNRS, 34293 Montpellier, France
| | - Charlotte Grimaud
- Institut de Recherche en Cancérologie de Montpellier (IRCM), INSERM U1194, Institut Régional du Cancer (ICM), Université de Montpellier, CNRS Route de Mende, 34293 Montpellier, France
| | - Cristina Viganò
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, 34293 Montpellier, France
| | - Francisca Méchali
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, 34293 Montpellier, France
| | - Séverine Boulon
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, 34293 Montpellier, France
| | - Olivier Coux
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, 34293 Montpellier, France
| | - Catherine Bonne-Andrea
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, 34293 Montpellier, France
| | - Véronique Baldin
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, 34293 Montpellier, France
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29
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Lobbia VR, Trueba Sanchez MC, van Ingen H. Beyond the Nucleosome: Nucleosome-Protein Interactions and Higher Order Chromatin Structure. J Mol Biol 2021; 433:166827. [PMID: 33460684 DOI: 10.1016/j.jmb.2021.166827] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 12/20/2022]
Abstract
The regulation of chromatin biology ultimately depends on the manipulation of its smallest subunit, the nucleosome. The proteins that bind and operate on the nucleosome do so, while their substrate is part of a polymer embedded in the dense nuclear environment. Their molecular interactions must in some way be tuned to deal with this complexity. Due to the rapid increase in the number of high-resolution structures of nucleosome-protein complexes and the increasing understanding of the cellular chromatin structure, it is starting to become clearer how chromatin factors operate in this complex environment. In this review, we analyze the current literature on the interplay between nucleosome-protein interactions and higher-order chromatin structure. We examine in what way nucleosomes-protein interactions can affect and can be affected by chromatin organization at the oligonucleosomal level. In addition, we review the characteristics of nucleosome-protein interactions that can cause phase separation of chromatin. Throughout, we hope to illustrate the exciting challenges in characterizing nucleosome-protein interactions beyond the nucleosome.
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Affiliation(s)
- Vincenzo R Lobbia
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Maria Cristina Trueba Sanchez
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
| | - Hugo van Ingen
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands.
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30
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Mivelaz M, Fierz B. Observing protein interaction dynamics to chemically defined chromatin fibers by colocalization single-molecule fluorescence microscopy. Methods 2020; 184:112-124. [PMID: 32004546 DOI: 10.1016/j.ymeth.2020.01.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 01/15/2020] [Accepted: 01/26/2020] [Indexed: 02/04/2023] Open
Abstract
In eukaryotic cells, the genome is packaged into chromatin and exists in different states, ranging from open euchromatic regions to highly condensed heterochromatic regions. Chromatin states are highly dynamic and are organized by an interplay of histone post-translational modifications and effector proteins, both of which are central in the regulation of gene expression. For this, chromatin effector proteins must first search the nucleus for their targets, before binding and performing their role. A key question is how chromatin effector proteins search, interact with and alter the different chromatin environments. Here we present a modular fluorescence based in vitro workflow to directly observe dynamic interactions of effector proteins with defined chromatin fibres, replicating different chromatin states. We discuss the design and creation of chromatin assemblies, the synthesis of modified histones, the fabrication of microchannels and the approach to data acquisition and analysis. All of this with the aim to better understand the complex in vivo relationship between chromatin structure and gene expression.
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Affiliation(s)
- Maxime Mivelaz
- École Polytechnique Fédérale de Lausanne, SB ISIC LCBM, Station 6, CH-1015 Lausanne, Switzerland
| | - Beat Fierz
- École Polytechnique Fédérale de Lausanne, SB ISIC LCBM, Station 6, CH-1015 Lausanne, Switzerland.
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31
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Pokorná P, Krepl M, Šponer J. Residues flanking the ARK me3T/S motif allow binding of diverse targets to the HP1 chromodomain: Insights from molecular dynamics simulations. Biochim Biophys Acta Gen Subj 2020; 1865:129771. [PMID: 33153976 DOI: 10.1016/j.bbagen.2020.129771] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/15/2020] [Accepted: 10/20/2020] [Indexed: 11/28/2022]
Abstract
BACKGROUND The chromodomain (CD) of HP1 proteins is an established H3K9me3 reader that also binds H1, EHMT2 and H3K23 lysine-methylated targets. Structural experiments have provided atomistic pictures of its recognition of the conserved ARKme3S/T motif, but structural dynamics' contribution to the recognition may have been masked by ensemble averaging. METHODS We acquired ~350 μs of explicit solvent molecular dynamics (MD) simulations of the CD domain interacting with several peptides using the latest AMBER force fields. RESULTS The simulations reproduced the experimentally observed static binding patterns well but also revealed visible structural dynamics at the interfaces. While the buried K0me3 and A-2 target residues are tightly bound, several flanking sidechains sample diverse sites on the CD surface. Different amino acid positions of the targets can substitute for each other by forming mutually replaceable interactions with CD, thereby explaining the lack of strict requirement for cationic H3 target residues at the -3 position. The Q-4 residue of H3 targets further stabilizes the binding. The recognition pattern of the H3K23 ATKme3A motif, for which no structure is available, is predicted. CONCLUSIONS The CD reads a longer target segment than previously thought, ranging from positions -7 to +3. The CD anionic clamp can be neutralized not only by the -3 and -1 residues, but also by -7, -6, -5 and +3 residues. GENERAL SIGNIFICANCE Structural dynamics, not immediately apparent from the structural data, contribute to molecular recognition between the HP1 CD domain and its targets. Mutual replaceability of target residues increases target sequence flexibility.
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Affiliation(s)
- Pavlína Pokorná
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
| | - Miroslav Krepl
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.
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32
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Mancini M, Papon L, Mangé A, Cammas F, Fabbrizio E. HP1s modulate the S-Adenosyl Methionine synthesis pathway in liver cancer cells. Biochem J 2020; 477:1033-47. [PMID: 32091571 DOI: 10.1042/BCJ20190621] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 02/20/2020] [Accepted: 02/24/2020] [Indexed: 12/24/2022]
Abstract
Hepatocellular carcinoma (HCC) is the most frequent primary liver cancer in adults. Among the altered pathways leading to HCC, an increasing role is attributed to abnormal epigenetic regulation. Members of the Heterochromatin Protein (HP1) 1 family are key players in chromatin organisation, acting as docking sites for chromatin modifiers. Here, we inactivated HP1α in HepG2 human liver carcinoma cells and showed that HP1α participated in cell proliferation. HP1α-depleted cells have a global decrease in DNA methylation and consequently a perturbed chromatin organisation, as exemplified by the reactivation of transcription at centromeric and pericentromeric regions, eventhough the protein levels of chromatin writers depositing methylation marks, such as EZH2, SETDB1, SUV39H1, G9A and DNMT3A remained unaltered. This decrease was attributed mainly to a low S-Adenosyl Methionine (SAM) level, a cofactor involved in methylation processes. Furthermore, we showed that this decrease was due to a modification in the Methionine adenosyl transferase 2A RNA (MAT2A) level, which modifies the ratio of MAT1A/MAT2A, two enzymes that generate SAM. Importantly, HP1α reintroduction into HP1α-depleted cells restored the MAT2A protein to its initial level. Finally, we demonstrated that this transcriptional deregulation of MAT2A in HP1α-depleted cells relied on a lack of recruitment of HP1β and HP1γ to MAT2A promoter where an improper non-CpG methylation site was promoted in the vicinity of the transcription start site where HP1β and HP1γ bound. Altogether, these results highlight an unanticipated link between HP1 and the SAM synthesis pathway, and emphasise emerging functions of HP1s as sensors of some aspects of liver cell metabolism.
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33
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Otake K, Ohzeki JI, Shono N, Kugou K, Okazaki K, Nagase T, Yamakawa H, Kouprina N, Larionov V, Kimura H, Earnshaw WC, Masumoto H. CENP-B creates alternative epigenetic chromatin states permissive for CENP-A or heterochromatin assembly. J Cell Sci 2020; 133:jcs243303. [PMID: 32661090 PMCID: PMC7438015 DOI: 10.1242/jcs.243303] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 06/29/2020] [Indexed: 01/03/2023] Open
Abstract
CENP-B binds to CENP-B boxes on centromeric satellite DNAs (known as alphoid DNA in humans). CENP-B maintains kinetochore function through interactions with CENP-A nucleosomes and CENP-C. CENP-B binding to transfected alphoid DNA can induce de novo CENP-A assembly, functional centromere and kinetochore formation, and subsequent human artificial chromosome (HAC) formation. Furthermore, CENP-B also facilitates H3K9 (histone H3 lysine 9) trimethylation on alphoid DNA, mediated by Suv39h1, at ectopic alphoid DNA integration sites. Excessive heterochromatin invasion into centromere chromatin suppresses CENP-A assembly. It is unclear how CENP-B controls such different chromatin states. Here, we show that the CENP-B acidic domain recruits histone chaperones and many chromatin modifiers, including the H3K36 methylase ASH1L, as well as the heterochromatin components Suv39h1 and HP1 (HP1α, β and γ, also known as CBX5, CBX1 and CBX3, respectively). ASH1L facilitates the formation of open chromatin competent for CENP-A assembly on alphoid DNA. These results indicate that CENP-B is a nexus for histone modifiers that alternatively promote or suppress CENP-A assembly by mutually exclusive mechanisms. Besides the DNA-binding domain, the CENP-B acidic domain also facilitates CENP-A assembly de novo on transfected alphoid DNA. CENP-B therefore balances CENP-A assembly and heterochromatin formation on satellite DNA.
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Affiliation(s)
- Koichiro Otake
- Laboratory of Chromosome Engineering, Department of Frontier Research and Development, Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu 292-0818, Japan
| | - Jun-Ichirou Ohzeki
- Laboratory of Chromosome Engineering, Department of Frontier Research and Development, Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu 292-0818, Japan
| | - Nobuaki Shono
- Laboratory of Chromosome Engineering, Department of Frontier Research and Development, Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu 292-0818, Japan
| | - Kazuto Kugou
- Laboratory of Chromosome Engineering, Department of Frontier Research and Development, Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu 292-0818, Japan
| | - Koei Okazaki
- Laboratory of Chromosome Engineering, Department of Frontier Research and Development, Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu 292-0818, Japan
| | - Takahiro Nagase
- Public Relations and Research Promotion Group, Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu 292-0818, Japan
| | - Hisashi Yamakawa
- Clinical Analysis Team, Department of Omics Research and Development, Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu 292-0818, Japan
| | - Natalay Kouprina
- Genome Structure and Function Group, Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Vladimir Larionov
- Genome Structure and Function Group, Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hiroshi Kimura
- Cell Biology Unit, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - William C Earnshaw
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Hiroshi Masumoto
- Laboratory of Chromosome Engineering, Department of Frontier Research and Development, Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu 292-0818, Japan
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Singh PB, Belyakin SN, Laktionov PP. Biology and Physics of Heterochromatin- Like Domains/Complexes. Cells 2020; 9:E1881. [PMID: 32796726 DOI: 10.3390/cells9081881] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/29/2020] [Accepted: 08/04/2020] [Indexed: 11/17/2022] Open
Abstract
The hallmarks of constitutive heterochromatin, HP1 and H3K9me2/3, assemble heterochromatin-like domains/complexes outside canonical constitutively heterochromatic territories where they regulate chromatin template-dependent processes. Domains are more than 100 kb in size; complexes less than 100 kb. They are present in the genomes of organisms ranging from fission yeast to human, with an expansion in size and number in mammals. Some of the likely functions of domains/complexes include silencing of the donor mating type region in fission yeast, preservation of DNA methylation at imprinted germline differentially methylated regions (gDMRs) and regulation of the phylotypic progression during vertebrate development. Far cis- and trans-contacts between micro-phase separated domains/complexes in mammalian nuclei contribute to the emergence of epigenetic compartmental domains (ECDs) detected in Hi-C maps. A thermodynamic description of micro-phase separation of heterochromatin-like domains/complexes may require a gestalt shift away from the monomer as the “unit of incompatibility” that determines the sign and magnitude of the Flory–Huggins parameter, χ. Instead, a more dynamic structure, the oligo-nucleosomal “clutch”, consisting of between 2 and 10 nucleosomes is both the long sought-after secondary structure of chromatin and its unit of incompatibility. Based on this assumption we present a simple theoretical framework that enables an estimation of χ for domains/complexes flanked by euchromatin and thereby an indication of their tendency to phase separate. The degree of phase separation is specified by χN, where N is the number of “clutches” in a domain/complex. Our approach could provide an additional tool for understanding the biophysics of the 3D genome.
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Sales-Gil R, Vagnarelli P. How HP1 Post-Translational Modifications Regulate Heterochromatin Formation and Maintenance. Cells 2020; 9:E1460. [PMID: 32545538 DOI: 10.3390/cells9061460] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 12/12/2022] Open
Abstract
Heterochromatin Protein 1 (HP1) is a highly conserved protein that has been used as a classic marker for heterochromatin. HP1 binds to di- and tri-methylated histone H3K9 and regulates heterochromatin formation, functions and structure. Besides the well-established phosphorylation of histone H3 Ser10 that has been shown to modulate HP1 binding to chromatin, several studies have recently highlighted the importance of HP1 post-translational modifications and additional epigenetic features for the modulation of HP1-chromatin binding ability and heterochromatin formation. In this review, we summarize the recent literature of HP1 post-translational modifications that have contributed to understand how heterochromatin is formed, regulated and maintained.
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Fioriniello S, Marano D, Fiorillo F, D'Esposito M, Della Ragione F. Epigenetic Factors That Control Pericentric Heterochromatin Organization in Mammals. Genes (Basel) 2020; 11:E595. [PMID: 32481609 DOI: 10.3390/genes11060595] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/17/2020] [Accepted: 05/25/2020] [Indexed: 12/11/2022] Open
Abstract
Pericentric heterochromatin (PCH) is a particular form of constitutive heterochromatin that is localized to both sides of centromeres and that forms silent compartments enriched in repressive marks. These genomic regions contain species-specific repetitive satellite DNA that differs in terms of nucleotide sequences and repeat lengths. In spite of this sequence diversity, PCH is involved in many biological phenomena that are conserved among species, including centromere function, the preservation of genome integrity, the suppression of spurious recombination during meiosis, and the organization of genomic silent compartments in the nucleus. PCH organization and maintenance of its repressive state is tightly regulated by a plethora of factors, including enzymes (e.g., DNA methyltransferases, histone deacetylases, and histone methyltransferases), DNA and histone methylation binding factors (e.g., MECP2 and HP1), chromatin remodeling proteins (e.g., ATRX and DAXX), and non-coding RNAs. This evidence helps us to understand how PCH organization is crucial for genome integrity. It then follows that alterations to the molecular signature of PCH might contribute to the onset of many genetic pathologies and to cancer progression. Here, we describe the most recent updates on the molecular mechanisms known to underlie PCH organization and function.
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Komarov PA, Sokolova O, Akulenko N, Brasset E, Jensen S, Kalmykova A. Epigenetic Requirements for Triggering Heterochromatinization and Piwi-Interacting RNA Production from Transgenes in the Drosophila Germline. Cells 2020; 9:E922. [PMID: 32290057 DOI: 10.3390/cells9040922] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 04/05/2020] [Accepted: 04/07/2020] [Indexed: 12/26/2022] Open
Abstract
Transgenes containing a fragment of the I retrotransposon represent a powerful model of piRNA cluster de novo formation in the Drosophila germline. We revealed that the same transgenes located at different genomic loci form piRNA clusters with various capacity of small RNA production. Transgenic piRNA clusters are not established in piRNA pathway mutants. However, in the wild-type context, the endogenous ancestral I-related piRNAs heterochromatinize and convert the I-containing transgenes into piRNA-producing loci. Here, we address how the quantitative level of piRNAs influences the heterochromatinization and piRNA production. We show that a minimal amount of maternal piRNAs from ancestral I-elements is sufficient to form the transgenic piRNA clusters. Supplemental piRNAs stemming from active I-element copies do not stimulate additional chromatin changes or piRNA production from transgenes. Therefore, chromatin changes and piRNA production are initiated by a minimum threshold level of complementary piRNAs, suggesting a selective advantage of prompt cell response to the lowest level of piRNAs. It is noteworthy that the weak piRNA clusters do not transform into strong ones after being targeted by abundant I-specific piRNAs, indicating the importance of the genomic context for piRNA cluster establishment. Analysis of ovarian transcription profiles suggests that regions facilitating convergent transcription favor the formation of transgenic piRNA clusters.
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Abstract
Active and inactive chromatin are spatially separated in the nucleus. In Hi-C data, this is reflected by the formation of compartments, whose interactions form a characteristic checkerboard pattern in chromatin interaction maps. Only recently have the mechanisms that drive this separation come into view. Here, we discuss new insights into these mechanisms and possible functions in genome regulation. Compartmentalization can be understood as a microphase-segregated block co-polymer. Microphase separation can be facilitated by chromatin factors that associate with compartment domains, and that can engage in liquid-liquid phase separation to form subnuclear bodies, as well as by acting as bridging factors between polymer sections. We then discuss how a spatially segregated state of the genome can contribute to gene regulation, and highlight experimental challenges for testing these structure-function relationships.
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Affiliation(s)
- Erica M Hildebrand
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Job Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
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Di Mauro G, Carbonell A, Escudero-Ferruz P, Azorín F. The zinc-finger proteins WOC and ROW play distinct functions within the HP1c transcription complex. Biochim Biophys Acta Gene Regul Mech 2020; 1863:194492. [PMID: 32006714 DOI: 10.1016/j.bbagrm.2020.194492] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 01/28/2020] [Accepted: 01/29/2020] [Indexed: 11/20/2022]
Abstract
In Drosophila, the Heterochromatin Protein 1c (HP1c) forms a transcriptional complex with the zinc-finger proteins WOC and ROW, and the extraproteasomal ubiquitin receptor Dsk2. This complex localizes at promoters of active genes and it is required for transcription. The functions played by the different components of the HP1c complex are not fully understood. In this study we show that WOC and ROW are required for chromatin binding of both Dsk2 and HP1c. However, while impairing chromatin binding strongly destabilizes HP1c, it does not affect Dsk2 stability. We also show that WOC, but not ROW, is required for nuclear localization of Dsk2. Moreover, WOC and Dsk2 co-immunoprecitate upon ROW depletion. These results suggest that WOC and Dsk2 interact to form a subcomplex that mediates nuclear translocation of Dsk2. We also show that ROW mediates chromatin binding of the WOC/Dsk2 subcomplex, as well as of HP1c. Altogether these observations favor a model by which the interaction with WOC recruits Dsk2 to the HP1c complex that, in its turn, binds chromatin in a ROW-dependent manner.
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Affiliation(s)
- Gianmarco Di Mauro
- Institute of Molecular Biology of Barcelona, CSIC, Baldiri Reixac, 10-12, 08028 Barcelona, Spain; Institute for Research in Biomedicine, IRB Barcelona, The Barcelona Institute for Science and Technology, Baldiri Reixac, 10-12, 08028 Barcelona, Spain
| | - Albert Carbonell
- Institute of Molecular Biology of Barcelona, CSIC, Baldiri Reixac, 10-12, 08028 Barcelona, Spain; Institute for Research in Biomedicine, IRB Barcelona, The Barcelona Institute for Science and Technology, Baldiri Reixac, 10-12, 08028 Barcelona, Spain
| | - Paula Escudero-Ferruz
- Institute of Molecular Biology of Barcelona, CSIC, Baldiri Reixac, 10-12, 08028 Barcelona, Spain; Institute for Research in Biomedicine, IRB Barcelona, The Barcelona Institute for Science and Technology, Baldiri Reixac, 10-12, 08028 Barcelona, Spain
| | - Fernando Azorín
- Institute of Molecular Biology of Barcelona, CSIC, Baldiri Reixac, 10-12, 08028 Barcelona, Spain; Institute for Research in Biomedicine, IRB Barcelona, The Barcelona Institute for Science and Technology, Baldiri Reixac, 10-12, 08028 Barcelona, Spain.
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40
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Iglesias N, Paulo JA, Tatarakis A, Wang X, Edwards AL, Bhanu NV, Garcia BA, Haas W, Gygi SP, Moazed D. Native Chromatin Proteomics Reveals a Role for Specific Nucleoporins in Heterochromatin Organization and Maintenance. Mol Cell 2020; 77:51-66.e8. [PMID: 31784357 DOI: 10.1016/j.molcel.2019.10.018] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 08/19/2019] [Accepted: 10/11/2019] [Indexed: 12/31/2022]
Abstract
Spatially and functionally distinct domains of heterochromatin and euchromatin play important roles in the maintenance of chromosome stability and regulation of gene expression, but a comprehensive knowledge of their composition is lacking. Here, we develop a strategy for the isolation of native Schizosaccharomyces pombe heterochromatin and euchromatin fragments and analyze their composition by using quantitative mass spectrometry. The shared and euchromatin-specific proteomes contain proteins involved in DNA and chromatin metabolism and in transcription, respectively. The heterochromatin-specific proteome includes all proteins with known roles in heterochromatin formation and, in addition, is enriched for subsets of nucleoporins and inner nuclear membrane (INM) proteins, which associate with different chromatin domains. While the INM proteins are required for the integrity of the nucleolus, containing ribosomal DNA repeats, the nucleoporins are required for aggregation of heterochromatic foci and epigenetic inheritance. The results provide a comprehensive picture of heterochromatin-associated proteins and suggest a role for specific nucleoporins in heterochromatin function.
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Marano D, Fioriniello S, Fiorillo F, Gibbons RJ, D'Esposito M, Della Ragione F. ATRX Contributes to MeCP2-Mediated Pericentric Heterochromatin Organization during Neural Differentiation. Int J Mol Sci 2019; 20:E5371. [PMID: 31671722 PMCID: PMC6862095 DOI: 10.3390/ijms20215371] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [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: 10/15/2019] [Accepted: 10/24/2019] [Indexed: 11/16/2022] Open
Abstract
Methyl-CpG binding protein 2 (MeCP2) is a multi-function factor involved in locus-specific transcriptional modulation and the regulation of genome architecture, e.g., pericentric heterochromatin (PCH) organization. MECP2 mutations are responsible for Rett syndrome (RTT), a devastating postnatal neurodevelopmental disorder, the pathogenetic mechanisms of which are still unknown. MeCP2, together with Alpha-thalassemia/mental retardation syndrome X-linked protein (ATRX), accumulates at chromocenters, which are repressive PCH domains. As with MECP2, mutations in ATRX cause ATR-X syndrome which is associated with severe intellectual disability. We exploited two murine embryonic stem cell lines, in which the expression of MeCP2 or ATRX is abolished. Through immunostaining, chromatin immunoprecipitation and western blot, we show that MeCP2 and ATRX are reciprocally dependent both for their expression and targeting to chromocenters. Moreover, ATRX plays a role in the accumulation of members of the heterochromatin protein 1 (HP1) family at PCH and, as MeCP2, modulates their expression. Furthermore, ATRX and HP1 targeting to chromocenters depends on an RNA component. 3D-DNA fluorescence in situ hybridization (FISH) highlighted, for the first time, a contribution of ATRX in MeCP2-mediated chromocenter clustering during neural differentiation. Overall, we provide a detailed dissection of the functional interplay between MeCP2 and ATRX in higher-order PCH organization in neurons. Our findings suggest molecular defects common to RTT and ATR-X syndrome, including an alteration in PCH.
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Affiliation(s)
- Domenico Marano
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', National Research Council (CNR), 80131 Naples, Italy.
| | - Salvatore Fioriniello
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', National Research Council (CNR), 80131 Naples, Italy.
| | - Francesca Fiorillo
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', National Research Council (CNR), 80131 Naples, Italy.
| | - Richard J Gibbons
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK.
| | - Maurizio D'Esposito
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', National Research Council (CNR), 80131 Naples, Italy.
| | - Floriana Della Ragione
- Institute of Genetics and Biophysics 'A. Buzzati-Traverso', National Research Council (CNR), 80131 Naples, Italy.
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Abstract
Origin recognition complex (ORC), a heteromeric six-subunit complex, is the central component of the eukaryotic pre-replication complex. Recent data from yeast, frogs, flies and mammals present compelling evidence that ORC and its individual subunits have nonreplicative functions as well. The majority of these functions, such as heterochromatin formation, chromosome condensation, and segregation are dependent on ORC-DNA interactions. Furthermore, ORC is involved in the control of cell division via its participation in centrosome duplication and cytokinesis. Recent findings have also demonstrated a direct interaction between ORC and mRNPs and highlighted an essential role of ORC in mRNA nuclear export. Along with the growth of evolutionary complexity of organisms, ORC complex functions become more elaborate and new functions of the ORC sub-complexes and individual subunits have emerged.
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Affiliation(s)
- Varvara V Popova
- a Department of Transcription Regulation and Chromatin Dynamics , Institute of Gene Biology, Russian Academy of Sciences , Moscow , Russia
| | - Alexander V Brechalov
- a Department of Transcription Regulation and Chromatin Dynamics , Institute of Gene Biology, Russian Academy of Sciences , Moscow , Russia
| | - Sofia G Georgieva
- a Department of Transcription Regulation and Chromatin Dynamics , Institute of Gene Biology, Russian Academy of Sciences , Moscow , Russia
| | - Daria V Kopytova
- a Department of Transcription Regulation and Chromatin Dynamics , Institute of Gene Biology, Russian Academy of Sciences , Moscow , Russia
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Wang L, Gao Y, Zheng X, Liu C, Dong S, Li R, Zhang G, Wei Y, Qu H, Li Y, Allis CD, Li G, Li H, Li P. Histone Modifications Regulate Chromatin Compartmentalization by Contributing to a Phase Separation Mechanism. Mol Cell 2019; 76:646-659.e6. [PMID: 31543422 DOI: 10.1016/j.molcel.2019.08.019] [Citation(s) in RCA: 194] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 07/08/2019] [Accepted: 08/20/2019] [Indexed: 02/02/2023]
Abstract
Eukaryotic chromosomes contain compartments of various functions, which are marked by and enriched with specific histone modifications. However, the molecular mechanisms by which these histone marks function in chromosome compartmentalization are poorly understood. Constitutive heterochromatin is a largely silent chromosome compartment characterized in part by H3K9me2 and 3. Here, we show that heterochromatin protein 1 (HP1), an H3K9me2 and 3 "reader," interacts with SUV39H1, an H3K9me2 and 3 "writer," and with TRIM28, an abundant HP1 scaffolding protein, to form complexes with increased multivalent engagement of H3K9me2 and 3-modified chromatin. H3K9me2 and 3-marked nucleosomal arrays and associated complexes undergo phase separation to form macromolecule-enriched liquid droplets. The droplets are reminiscent of heterochromatin as they are highly dense chromatin-containing structures that are resistant to DNase and exclude the general transcription factor TFIIB. Our data suggest a general mechanism by which histone marks regulate chromosome compartmentalization by promoting phase separation.
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Affiliation(s)
- Liang Wang
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yifei Gao
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiangdong Zheng
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China; Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Cuifang Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Shuangshuang Dong
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ru Li
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Guanwei Zhang
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yixuan Wei
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hongyuan Qu
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China; Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Yuhan Li
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - C David Allis
- Laboratory of Chromatin Biology and Epigenetics, Rockefeller University, New York, NY 10065, USA
| | - Guohong Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Haitao Li
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China; Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing 100084, China.
| | - Pilong Li
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China; Laboratory of Chromatin Biology and Epigenetics, Rockefeller University, New York, NY 10065, USA.
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Legartová S, Lochmanová G, Zdráhal Z, Kozubek S, Šponer J, Krepl M, Pokorná P, Bártová E. DNA Damage Changes Distribution Pattern and Levels of HP1 Protein Isoforms in the Nucleolus and Increases Phosphorylation of HP1β-Ser88. Cells 2019; 8:E1097. [PMID: 31533340 DOI: 10.3390/cells8091097] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/10/2019] [Accepted: 09/10/2019] [Indexed: 12/28/2022] Open
Abstract
The family of heterochromatin protein 1 (HP1) isoforms is essential for chromatin packaging, regulation of gene expression, and repair of damaged DNA. Here we document that γ-radiation reduced the number of HP1α-positive foci, but not HP1β and HP1γ foci, located in the vicinity of the fibrillarin-positive region of the nucleolus. The additional analysis confirmed that γ-radiation has the ability to significantly decrease the level of HP1α in rDNA promoter and rDNA encoding 28S rRNA. By mass spectrometry, we showed that treatment by γ-rays enhanced the HP1β serine 88 phosphorylation (S88ph), but other analyzed modifications of HP1β, including S161ph/Y163ph, S171ph, and S174ph, were not changed in cells exposed to γ-rays or treated by the HDAC inhibitor (HDACi). Interestingly, a combination of HDACi and γ-radiation increased the level of HP1α and HP1γ. The level of HP1β remained identical before and after the HDACi/γ-rays treatment, but HDACi strengthened HP1β interaction with the KRAB-associated protein 1 (KAP1) protein. Conversely, HP1γ did not interact with KAP1, although approximately 40% of HP1γ foci co-localized with accumulated KAP1. Especially HP1γ foci at the periphery of nucleoli were mostly absent of KAP1. Together, DNA damage changed the morphology, levels, and interaction properties of HP1 isoforms. Also, γ-irradiation-induced hyperphosphorylation of the HP1β protein; thus, HP1β-S88ph could be considered as an important marker of DNA damage.
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Okamoto K, Tanaka Y, Ogasawara S, Obuse C, Nakayama JI, Yano H, Tsuneoka M. KDM2A-dependent reduction of rRNA transcription on glucose starvation requires HP1 in cells, including triple-negative breast cancer cells. Oncotarget 2019; 10:4743-4760. [PMID: 31413816 PMCID: PMC6677663 DOI: 10.18632/oncotarget.27092] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 06/29/2019] [Indexed: 12/24/2022] Open
Abstract
Triple-negative breast cancer (TNBC) is very aggressive and lacks specific therapeutic targets. Ribosome RNAs (rRNAs) are central components of ribosomes and transcribed in nucleoli, and the level of rRNA transcription greatly affects ribosome production and cell proliferation. We have reported that an epigenetic protein, KDM2A, exists in nucleoli and reduces rRNA transcription on glucose starvation. However, the molecular mechanism is still unclear. The purpose of this study is to examine the KDM2A-dependent regulation mechanism of rRNA transcription. In this study, we turned our attention to the nucleolar accumulation of KDM2A. We found that KDM2A had multiple regions for its nucleolar localization, and one of the regions was directly bound by heterochromatin protein 1γ (HP1γ) using valine 801 in the LxVxL motif of KDM2A. A knockdown of HP1γ or a point mutation of valine 801 in KDM2A decreased the nucleolar accumulation of KDM2A, and suppressed the reduction of rRNA transcription on glucose starvation. These results uncovered a novel function of HP1γ: the regulation of rRNA transcription, and suggested that HP1γ stimulates the nucleolar accumulation of KDM2A to support the KDM2A-dependent regulation of rRNA transcription. HP1γ was expressed in cancer cells in all breast carcinoma tissues examined, including TNBC tissues. A knockdown of HP1γ in a TNBC cell line, MDA-MB-231 cells, reduced the nucleolar accumulation of KDM2A, and suppressed the reductions of rRNA transcription and cell proliferation on glucose starvation. These results suggest that the KDM2A-dependent regulation of rRNA transcription requires HP1γ, and thus may be applicable to the treatment of TNBC.
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Affiliation(s)
- Kengo Okamoto
- Laboratory of Molecular and Cellular Biology, Faculty of Pharmacy, Takasaki University of Health and Welfare, Takasaki, Japan
| | - Yuji Tanaka
- Laboratory of Molecular and Cellular Biology, Faculty of Pharmacy, Takasaki University of Health and Welfare, Takasaki, Japan
| | - Sachiko Ogasawara
- Department of Pathology, Kurume University School of Medicine, Kurume, Japan
| | - Chikashi Obuse
- Department of Biological Sciences, Graduate School of Science, Osaka University, Osaka Japan
| | - Jun-Ichi Nakayama
- Division of Chromatin Regulation, National Institute for Basic Biology, Okazaki, Japan
| | - Hirohisa Yano
- Department of Pathology, Kurume University School of Medicine, Kurume, Japan
| | - Makoto Tsuneoka
- Laboratory of Molecular and Cellular Biology, Faculty of Pharmacy, Takasaki University of Health and Welfare, Takasaki, Japan
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MacDonald IA, Butler KV, Herring LE, Clinkscales SE, Yelagandula R, Stecher K, Bell O, Graves LM, Jin J, Hathaway NA. Pathway-Based High-Throughput Chemical Screen Identifies Compounds That Decouple Heterochromatin Transformations. SLAS Discov 2019; 24:802-816. [PMID: 31145866 DOI: 10.1177/2472555219849838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Heterochromatin protein 1 (HP1) facilitates the formation of repressive heterochromatin domains by recruiting histone lysine methyltransferase enzymes to chromatin, resulting in increased levels of histone H3K9me3. To identify chemical inhibitors of the HP1-heterochromatin gene repression pathway, we combined a cell-based assay that utilized chemical-mediated recruitment of HP1 to an endogenous active gene with high-throughput flow cytometry. Here we characterized small molecule inhibitors that block HP1-mediated heterochromatin formation. Our lead compounds demonstrated dose-dependent inhibition of HP1-stimulated gene repression and were validated in an orthogonal cell-based system. One lead inhibitor was improved by a change in stereochemistry, resulting in compound 2, which was further used to decouple the inverse relationship between H3K9 and H3K4 methylation states. We identified molecular components that bound compound 2, either directly or indirectly, by chemical affinity purification with a biotin-tagged derivative, followed by quantitative proteomic techniques. In summary, our pathway-based chemical screening approach resulted in the discovery of new inhibitors of HP1-mediated heterochromatin formation while identifying exciting new molecular interactions in the pathway to explore in the future. This modular platform can be expanded to test a wide range of chromatin modification pathways yielding inhibitors that are cell permeable and function in a physiologically relevant setting.
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Affiliation(s)
- Ian A MacDonald
- 1 The Eshelman School of Pharmacy, Division of Chemical Biology and Medicinal Chemistry, Center for Integrative Chemical Biology and Drug Discovery, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Kyle V Butler
- 2 Mount Sinai Center for Therapeutics Discovery, Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Laura E Herring
- 3 Department of Pharmacology, UNC Michael Hooker Proteomics Core Facility, University of North Carolina, Chapel Hill, NC, USA
| | - Sarah E Clinkscales
- 1 The Eshelman School of Pharmacy, Division of Chemical Biology and Medicinal Chemistry, Center for Integrative Chemical Biology and Drug Discovery, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ramesh Yelagandula
- 4 Institute of Molecular Biotechnology of the Austrian Academy of Science (IMBA), Vienna Biocenter (VBC), Vienna, Austria
| | - Karin Stecher
- 4 Institute of Molecular Biotechnology of the Austrian Academy of Science (IMBA), Vienna Biocenter (VBC), Vienna, Austria
| | - Oliver Bell
- 4 Institute of Molecular Biotechnology of the Austrian Academy of Science (IMBA), Vienna Biocenter (VBC), Vienna, Austria.,5 Department of Biochemistry and Molecular Medicine, University of Southern California, Norris Comprehensive Cancer Center, Los Angeles, CA, USA
| | - Lee M Graves
- 3 Department of Pharmacology, UNC Michael Hooker Proteomics Core Facility, University of North Carolina, Chapel Hill, NC, USA
| | - Jian Jin
- 2 Mount Sinai Center for Therapeutics Discovery, Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Nathaniel A Hathaway
- 1 The Eshelman School of Pharmacy, Division of Chemical Biology and Medicinal Chemistry, Center for Integrative Chemical Biology and Drug Discovery, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Loza-Coll MA, Petrossian CC, Boyle ML, Jones DL. Heterochromatin Protein 1 ( HP1) inhibits stem cell proliferation induced by ectopic activation of the Jak/STAT pathway in the Drosophila testis. Exp Cell Res 2019; 377:1-9. [PMID: 30817931 DOI: 10.1016/j.yexcr.2019.02.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [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: 12/29/2018] [Revised: 02/22/2019] [Accepted: 02/24/2019] [Indexed: 11/18/2022]
Abstract
Stem cells can divide asymmetrically with respect to cell fate, producing a copy of themselves (self-renewal), while giving rise to progeny that will differentiate along a specific lineage. Mechanisms that bias the balance towards self-renewal or extend the proliferative capacity of the differentiating progeny can result in tissue overgrowth and, eventually, the formation of tumors. Recent work has explored the role of heterochromatin and heterochromatin-associated proteins in the regulation of stem cell behavior under homeostatic conditions, but less is known about their possible roles in potentiating or suppressing stem cell overproliferation. Here we used ectopic activation of the Jak/STAT pathway in germline and somatic stem cells of the D. melanogaster testis as an in vivo model to probe the function of Heterochromatin Protein 1 (HP1) in stem cell overproliferation. Forced expression of HP1 in either early germ or somatic cells suppressed the overgrowth of testes in response to ectopic Jak/STAT activation. Interestingly, HP1 expression led to distinct phenotypes, depending on whether it was overexpressed in somatic or germ cells, possibly reflecting different cell-autonomous and non-autonomous effects in each cell type. Our results provide a new framework for further in vivo studies aimed at understanding the interactions between heterochromatin and uncontrolled stem cell proliferation, as well as the complex cross-regulatory interactions between the somatic and germline lineages in the Drosophila testis.
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Affiliation(s)
| | | | | | - D Leanne Jones
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, 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
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Abstract
The nuclear lamina (NL) is a meshwork of lamins and lamin-associated proteins adjoining the inner side of the nuclear envelope. In early embryonic cells, the NL mainly suppresses background transcription, whereas, in differentiated cell types, its disruption affects gene expression more severely. Normally, the NL serves as a backbone for multiple chromatin anchoring sites, thus shaping the spatial organization of chromosomes in the interphase nucleus. However, upon cell senescence, aging, or in some types of terminally differentiated cells and lamin-associated diseases, the loss of NL-chromatin tethering causes drastic alterations in chromosome architecture. Here, we provide an overview of the recent advances in the field of NL-chromatin interactions, focusing on their impact on chromatin positioning, compaction, repression, and spatial organization.
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Affiliation(s)
- Yuri Y. Shevelyov
- Department of Molecular Genetics of Cell, Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia;
| | - Sergey V. Ulianov
- Division of the Regulation of Transcription and Chromatin Dynamics, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia;
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Yang F, Quan Z, Huang H, He M, Liu X, Cai T, Xi R. Ovaries absent links dLsd1 to HP1a for local H3K4 demethylation required for heterochromatic gene silencing. eLife 2019; 8:40806. [PMID: 30648969 PMCID: PMC6335052 DOI: 10.7554/elife.40806] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 12/20/2018] [Indexed: 12/30/2022] Open
Abstract
Heterochromatin Protein 1 (HP1) is a conserved chromosomal protein in eukaryotic cells that has a major role in directing heterochromatin formation, a process that requires co-transcriptional gene silencing mediated by small RNAs and their associated argonaute proteins. Heterochromatin formation requires erasing the active epigenetic mark, such as H3K4me2, but the molecular link between HP1 and H3K4 demethylation remains unclear. In a fertility screen in female Drosophila, we identified ovaries absent (ova), which functions in the stem cell niche, downstream of Piwi, to support germline stem cell differentiation. Moreover, ova acts as a suppressor of position effect variegation, and is required for silencing telomeric transposons in the germline. Biochemically, Ova acts to link the H3K4 demethylase dLsd1 to HP1a for local histone modifications. Therefore, our study provides a molecular connection between HP1a and local H3K4 demethylation during HP1a-mediated gene silencing that is required for ovary development, transposon silencing, and heterochromatin formation. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter). The complete set of genetic material within a cell is known as a genome. The genomes of human and other animal cells have regions of active genes interspersed with ‘dark’ regions known as heterochromatin, which contain genes and other types of genetic material that have been inactivated. Heterochromatin commonly contains sections of genetic material known as transposons. When a transposon is active it is able to move around the genome, therefore, inactivating (or ‘silencing’) transposons helps to maintain the integrity of the genetic material in a cell. It is particularly important to silence transposons in the stem cells that produce sperm and egg cells – known as germline stem cells – to ensure genetic information is faithfully passed on to the next generation. A protein called HP1a plays a major role in directing where heterochromatin forms in the genome. This process requires an enzyme called dLsd1 to remove a small tag from the genetic material but it is not clear how HP1a regulates the activity of dLsd1. To address this question, Yang et al. studied how egg cells form in fruit flies, which are often used as models of animal biology in experiments. The team screened a population of fruit flies that carried mutations in many different genes to identify genes that affect the fertility of female flies. This revealed a gene named as ovaries absent (or ova for short) is required for egg cells to form. In germline stem cells ova silences transposons and in the surrounding tissue it represses a specific signal that usually maintains stem cells to allow the stem cells to divide to make egg cells. Further experiments using biochemical techniques found that the protein encoded by ova acts as a bridge to bring HP1a and dLsd1 together to silence genes in heterochromatin. The next step would be to identify the functional counterpart of the ova gene in mammals, including humans, which may help to discover causes of infertility and develop new fertility treatment.
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Affiliation(s)
- Fu Yang
- National Institute of Biological Sciences, Beijing, China
| | - Zhenghui Quan
- National Institute of Biological Sciences, Beijing, China
| | - Huanwei Huang
- National Institute of Biological Sciences, Beijing, China
| | - Minghui He
- National Institute of Biological Sciences, Beijing, China
| | - Xicheng Liu
- National Institute of Biological Sciences, Beijing, China
| | - Tao Cai
- National Institute of Biological Sciences, Beijing, China
| | - Rongwen Xi
- National Institute of Biological Sciences, Beijing, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
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50
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Pindyurin AV, Ilyin AA, Ivankin AV, Tselebrovsky MV, Nenasheva VV, Mikhaleva EA, Pagie L, van Steensel B, Shevelyov YY. The large fraction of heterochromatin in Drosophila neurons is bound by both B-type lamin and HP1a. Epigenetics Chromatin 2018; 11:65. [PMID: 30384843 PMCID: PMC6211408 DOI: 10.1186/s13072-018-0235-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 10/26/2018] [Indexed: 12/22/2022] Open
Abstract
Background In most mammalian cell lines, chromatin located at the nuclear periphery is represented by condensed heterochromatin, as evidenced by microscopy observations and DamID mapping of lamina-associated domains (LADs) enriched in dimethylated Lys9 of histone H3 (H3K9me2). However, in Kc167 cell culture, the only Drosophilla cell type where LADs have previously been mapped, they are neither H3K9me2-enriched nor overlapped with the domains of heterochromatin protein 1a (HP1a). Results Here, using cell type-specific DamID we mapped genome-wide LADs, HP1a and Polycomb (Pc) domains from the central brain, Repo-positive glia, Elav-positive neurons and the fat body of Drosophila third instar larvae. Strikingly, contrary to Kc167 cells of embryonic origin, in neurons and, to a lesser extent, in glia and the fat body, HP1a domains appear to overlap strongly with LADs in both the chromosome arms and pericentromeric regions. Accordingly, centromeres reside closer to the nuclear lamina in neurons than in Kc167 cells. As expected, active gene promoters are mostly not present in LADs, HP1a and Pc domains. These domains are occupied by silent or weakly expressed genes with genes residing in the HP1a-bound LADs expressed at the lowest level. Conclusions In various differentiated Drosophila cell types, we discovered the existence of peripheral heterochromatin, similar to that observed in mammals. Our findings support the model that peripheral heterochromatin matures enhancing the repression of unwanted genes as cells terminally differentiate. Electronic supplementary material The online version of this article (10.1186/s13072-018-0235-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alexey V Pindyurin
- Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX, Amsterdam, The Netherlands. .,Department of Regulation of Genetic Processes, Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia, 630090. .,Laboratory of Structural, Functional and Comparative Genomics, Novosibirsk State University, Novosibirsk, Russia, 630090.
| | - Artem A Ilyin
- Department of Molecular Genetics of Cell, Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia, 123182
| | - Anton V Ivankin
- Department of Regulation of Genetic Processes, Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia, 630090
| | - Mikhail V Tselebrovsky
- Department of Molecular Genetics of Cell, Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia, 123182.,QC Biochemistry Lab, Yaroslavl Pharmaceutical Complex for Production of Finished Dosage Forms, R-Pharm Group, Yaroslavl, Russia, 150061
| | - Valentina V Nenasheva
- Department of Viral and Cellular Molecular Genetics, Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia, 123182
| | - Elena A Mikhaleva
- Department of Molecular Genetics of Cell, Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia, 123182
| | - Ludo Pagie
- Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX, Amsterdam, The Netherlands
| | - Bas van Steensel
- Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX, Amsterdam, The Netherlands.,Department of Cell Biology, Erasmus University Medical Center, 3015 GE, Rotterdam, The Netherlands
| | - Yuri Y Shevelyov
- Department of Molecular Genetics of Cell, Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia, 123182.
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