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Shi Q, Song G, Song L, Wang Y, Ma J, Zhang L, Yuan E. Unravelling the function of prdm16 in human tumours: A comparative analysis of haematologic and solid tumours. Biomed Pharmacother 2024; 178:117281. [PMID: 39137651 DOI: 10.1016/j.biopha.2024.117281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 08/03/2024] [Accepted: 08/07/2024] [Indexed: 08/15/2024] Open
Abstract
Extensive research has shown that PR domain 16 (PRDM16) plays a critical role in adipose tissue metabolism, including processes such as browning and thermogenesis of adipocytes, beigeing of adipocytes, and adipogenic differentiation of myoblasts. These functions have been associated with diseases such as obesity and diabetes. Additionally, PRDM16 has been correlated with various other conditions, including migraines, heterochromatin abnormalities, metabolic syndrome, cardiomyopathy, sarcopenia, nonsyndromic cleft lip, and essential hypertension, among others. However, there is currently no systematic or comprehensive conclusion regarding the mechanism of PRDM16 in human tumours, including haematologic and solid tumours. The aim of this review is to provide an overview of the research progress on PRDM16 in haematologic and solid tumours by incorporating recent literature findings. Furthermore, we explore the prospects of PRDM16 in the precise diagnosis and treatment of human haematologic and solid tumours.
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Affiliation(s)
- Qianqian Shi
- Department of Laboratory Medicine, the Third Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China; Zhengzhou Key Laboratory for In Vitro Diagnosis of Hypertensive Disorders of Pregnancy, Zhengzhou, Henan 450052, China; Tianjian Laboratory of Advanced Biomedical Sciences, Institute of Advanced Biomedical Sciences, Zhengzhou University, Zhengzhou, Henan 450000, China.
| | - Guangyong Song
- Department of Laboratory Medicine, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Liying Song
- Department of Laboratory Medicine, the Third Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China; Zhengzhou Key Laboratory for In Vitro Diagnosis of Hypertensive Disorders of Pregnancy, Zhengzhou, Henan 450052, China
| | - Yu Wang
- Department of Laboratory Medicine, the Third Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China; Zhengzhou Key Laboratory for In Vitro Diagnosis of Hypertensive Disorders of Pregnancy, Zhengzhou, Henan 450052, China
| | - Jun Ma
- Department of Laboratory Medicine, the Third Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China; Zhengzhou Key Laboratory for In Vitro Diagnosis of Hypertensive Disorders of Pregnancy, Zhengzhou, Henan 450052, China
| | - Linlin Zhang
- Department of Laboratory Medicine, the Third Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China; Zhengzhou Key Laboratory for In Vitro Diagnosis of Hypertensive Disorders of Pregnancy, Zhengzhou, Henan 450052, China; Tianjian Laboratory of Advanced Biomedical Sciences, Institute of Advanced Biomedical Sciences, Zhengzhou University, Zhengzhou, Henan 450000, China.
| | - Enwu Yuan
- Department of Laboratory Medicine, the Third Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China; Zhengzhou Key Laboratory for In Vitro Diagnosis of Hypertensive Disorders of Pregnancy, Zhengzhou, Henan 450052, China; Tianjian Laboratory of Advanced Biomedical Sciences, Institute of Advanced Biomedical Sciences, Zhengzhou University, Zhengzhou, Henan 450000, China.
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2
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Stutzman AV, Hill CA, Armstrong RL, Gohil R, Duronio RJ, Dowen JM, McKay DJ. Heterochromatic 3D genome organization is directed by HP1a- and H3K9-dependent and independent mechanisms. Mol Cell 2024; 84:2017-2035.e6. [PMID: 38795706 PMCID: PMC11185254 DOI: 10.1016/j.molcel.2024.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 03/07/2024] [Accepted: 05/02/2024] [Indexed: 05/28/2024]
Abstract
Whether and how histone post-translational modifications and the proteins that bind them drive 3D genome organization remains unanswered. Here, we evaluate the contribution of H3K9-methylated constitutive heterochromatin to 3D genome organization in Drosophila tissues. We find that the predominant organizational feature of wild-type tissues is the segregation of euchromatic chromosome arms from heterochromatic pericentromeres. Reciprocal perturbation of HP1a⋅H3K9me binding, using a point mutation in the HP1a chromodomain or replacement of the replication-dependent histone H3 with H3K9R mutant histones, revealed that HP1a binding to methylated H3K9 in constitutive heterochromatin is required to limit contact frequency between pericentromeres and chromosome arms and regulate the distance between arm and pericentromeric regions. Surprisingly, the self-association of pericentromeric regions is largely preserved despite the loss of H3K9 methylation and HP1a occupancy. Thus, the HP1a⋅H3K9 interaction contributes to but does not solely drive the segregation of euchromatin and heterochromatin inside the nucleus.
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Affiliation(s)
- Alexis V Stutzman
- Curriculum in Genetics & Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Christina A Hill
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Robin L Armstrong
- Curriculum in Genetics & Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Riya Gohil
- Curriculum in Genetics & Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Robert J Duronio
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA.
| | - Jill M Dowen
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Biochemistry & Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA.
| | - Daniel J McKay
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA.
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3
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Koryakov DE. Diversity and functional specialization of H3K9-specific histone methyltransferases. Bioessays 2024; 46:e2300163. [PMID: 38058121 DOI: 10.1002/bies.202300163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/16/2023] [Accepted: 11/20/2023] [Indexed: 12/08/2023]
Abstract
Histone modifications play a critical role in the control over activities of the eukaryotic genome; among these chemical alterations, the methylation of lysine K9 in histone H3 (H3K9) is one of the most extensively studied. The number of enzymes capable of methylating H3K9 varies greatly across different organisms: in fission yeast, only one such methyltransferase is present, whereas in mammals, 10 are known. If there are several such enzymes, each of them must have some specific function, and they can interact with one another. Thus arises a complex system of interchangeability, "division of labor," and contacts with each other and with diverse proteins. Histone methyltransferases specialize in the number of methyl groups that they attach and have different intracellular localizations as well as different distributions on chromosomes. Each also shows distinct binding to different types of sequences and has a specific set of nonhistone substrates.
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Affiliation(s)
- Dmitry E Koryakov
- Lab of Molecular Cytogenetics, Institute of Molecular and Cellular Biology, Novosibirsk, Russia
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4
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Romanov SE, Shloma VV, Maksimov DA, Koryakov DE. SetDB1 and Su(var)3-9 are essential for late stages of larval development of Drosophila melanogaster. Chromosome Res 2023; 31:35. [PMID: 38099968 DOI: 10.1007/s10577-023-09743-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 10/25/2023] [Accepted: 11/02/2023] [Indexed: 12/18/2023]
Abstract
Methylation of H3K9 histone residue is a marker of gene silencing in eukaryotes. Three enzymes responsible for adding this modification - G9a, SetDB1/Egg, and Su(var)3-9 - are known in Drosophila. To understand how simultaneous mutations of SetDB1 and Su(var)3-9 may affect the fly development, appropriate combinations were obtained. Double mutants egg; Su(var)3-9 displayed pronounced embryonic lethality, slower larval growth and died before or during metamorphosis. Analysis of transcription in larval salivary glands and wing imaginal disks indicated that the effect of double mutation is tissue-specific. In salivary gland chromosomes, affected genes display low H3K9me2 enrichment and are rarely bound by SetDB1 or Su(var)3-9. We suppose that each of these enzymes directly or indirectly controls its own set of gene targets in different organs, and double mutation results in an imbalanced developmental program. This also indicates that SetDB1 and Su(var)3-9 may affect transcription via H3K9-independent mechanisms. Unexpectedly, in double and triple mutants, amount of di- and tri-methylated H3K9 is drastically reduced, but not completely absent. We hypothesize that this residual methylation implies the existence of additional H3K9-specific methyltransferase in Drosophila.
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Affiliation(s)
- Stanislav E Romanov
- Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, 630090, Russia
| | - Viktor V Shloma
- Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, 630090, Russia
| | - Daniil A Maksimov
- Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, 630090, Russia
| | - Dmitry E Koryakov
- Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, 630090, Russia.
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5
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Shi Y, Qi W. Histone Modifications in NAFLD: Mechanisms and Potential Therapy. Int J Mol Sci 2023; 24:14653. [PMID: 37834101 PMCID: PMC10572202 DOI: 10.3390/ijms241914653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/03/2023] [Accepted: 09/09/2023] [Indexed: 10/15/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a progressive condition that encompasses a spectrum of liver disorders, beginning with the simple steatosis, progressing to nonalcoholic steatohepatitis (NASH), and possibly leading to more severe diseases, including liver cirrhosis and hepatocellular carcinoma (HCC). In recent years, the prevalence of NAFLD has increased due to a shift towards energy-dense dietary patterns and a sedentary lifestyle. NAFLD is also strongly associated with metabolic disorders such as obesity and hyperlipidemia. The progression of NAFLD could be influenced by a variety of factors, such as diet, genetic factors, and even epigenetic factors. In contrast to genetic factors, epigenetic factors, including histone modifications, exhibit dynamic and reversible features. Therefore, the epigenetic regulation of the initiation and progression of NAFLD is one of the directions under intensive investigation in terms of pathogenic mechanisms and possible therapeutic interventions. This review aims to discuss the possible mechanisms and the crucial role of histone modifications in the framework of epigenetic regulation in NAFLD, which may provide potential therapeutic targets and a scientific basis for the treatment of NAFLD.
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Affiliation(s)
- Yulei Shi
- Gene Editing Center, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Wei Qi
- Gene Editing Center, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
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6
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Boldyreva LV, Andreyeva EN, Pindyurin AV. Position Effect Variegation: Role of the Local Chromatin Context in Gene Expression Regulation. Mol Biol 2022. [DOI: 10.1134/s0026893322030049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Jiang N, Yang M, Han Y, Zhao H, Sun L. PRDM16 Regulating Adipocyte Transformation and Thermogenesis: A Promising Therapeutic Target for Obesity and Diabetes. Front Pharmacol 2022; 13:870250. [PMID: 35462933 PMCID: PMC9024053 DOI: 10.3389/fphar.2022.870250] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 03/11/2022] [Indexed: 11/13/2022] Open
Abstract
Given that obesity and diabetes have been major public health concerns and that disease morbidities have been rising continuously, effective treatment for these diseases is urgently needed. Because adipose tissue metabolism is involved in the progression of obesity and diabetes, it might be efficient to target adipocyte metabolic pathways. Positive regulatory domain zinc finger region protein 16 (PRDM16), a transcription factor that is highly expressed in adipocytes, plays a key role in adipose tissue metabolism, such as the browning and thermogenesis of adipocytes, the beigeing of adipocytes, the adipogenic differentiation of myoblasts, and the conversion of visceral adipocytes to subcutaneous adipocytes. Furthermore, clinical and basic studies have shown that the expression of PRDM16 is associated with obesity and diabetes and that PRDM16 signaling participates in the treatment of the two diseases. For example, metformin promotes thermogenesis and alleviates obesity by activating the AMPK/αKG/PRDM16 signaling pathway; rosiglitazone alleviates obesity under the synergistic effect of PRDM16; resveratrol plays an antiobesity role by inducing the expression of PRDM16; liraglupeptide improves insulin resistance by inducing the expression of PRDM16; and mulberry leaves play an anti-inflammatory and antidiabetes role by activating the expression of brown fat cell marker genes (including PRDM16). In this review, we summarize the evidence of PRDM16 involvement in the progression of obesity and diabetes and that PRDM16 may be a promising therapy for obesity and diabetes.
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Fefelova EA, Pleshakova IM, Mikhaleva EA, Pirogov SA, Poltorachenko V, Abramov Y, Romashin D, Shatskikh A, Blokh R, Gvozdev V, Klenov M. Impaired function of rDNA transcription initiation machinery leads to derepression of ribosomal genes with insertions of R2 retrotransposon. Nucleic Acids Res 2022; 50:867-884. [PMID: 35037046 PMCID: PMC8789037 DOI: 10.1093/nar/gkab1276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 11/21/2021] [Accepted: 12/14/2021] [Indexed: 12/14/2022] Open
Abstract
Eukaryotic genomes harbor hundreds of rRNA genes, many of which are transcriptionally silent. However, little is known about selective regulation of individual rDNA units. In Drosophila melanogaster, some rDNA repeats contain insertions of the R2 retrotransposon, which is capable to be transcribed only as part of pre-rRNA molecules. rDNA units with R2 insertions are usually inactivated, although R2 expression may be beneficial in cells with decreased rDNA copy number. Here we found that R2-inserted rDNA units are enriched with HP1a and H3K9me3 repressive mark, whereas disruption of the heterochromatin components slightly affects their silencing in ovarian germ cells. Surprisingly, we observed a dramatic upregulation of R2-inserted rRNA genes in ovaries lacking Udd (Under-developed) or other subunits (TAF1b and TAF1c-like) of the SL1-like complex, which is homologues to mammalian Selective factor 1 (SL1) involved in rDNA transcription initiation. Derepression of rRNA genes with R2 insertions was accompanied by a reduction of H3K9me3 and HP1a enrichment. We suggest that the impairment of the SL1-like complex affects a mechanism of selective activation of intact rDNA units which competes with heterochromatin formation. We also propose that R2 derepression may serve as an adaptive response to compromised rRNA synthesis.
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Affiliation(s)
- Elena A Fefelova
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena 91125, USA
| | - Irina M Pleshakova
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
- Laboratory for Neurobiology of Memory, P.K. Anokhin Institute of Normal Physiology, Moscow 125315, Russia
| | - Elena A Mikhaleva
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
| | - Sergei A Pirogov
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
| | - Valentin A Poltorachenko
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
| | - Yuri A Abramov
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
| | - Daniil D Romashin
- Laboratory of Precision Biosystems, V. N. Orekhovich Institute of Biomedical Chemistry, 10 Pogodinskaya St., Moscow 119121, Russia
| | - Aleksei S Shatskikh
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
| | - Roman S Blokh
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
- Department of Functional Genomics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilova Street, Moscow 119334, Russia
| | - Vladimir A Gvozdev
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
| | - Mikhail S Klenov
- Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», Moscow 123182, Russia
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Torres-Campana D, Horard B, Denaud S, Benoit G, Loppin B, Orsi GA. Three classes of epigenomic regulators converge to hyperactivate the essential maternal gene deadhead within a heterochromatin mini-domain. PLoS Genet 2022; 18:e1009615. [PMID: 34982772 PMCID: PMC8759638 DOI: 10.1371/journal.pgen.1009615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 01/14/2022] [Accepted: 12/10/2021] [Indexed: 11/24/2022] Open
Abstract
The formation of a diploid zygote is a highly complex cellular process that is entirely controlled by maternal gene products stored in the egg cytoplasm. This highly specialized transcriptional program is tightly controlled at the chromatin level in the female germline. As an extreme case in point, the massive and specific ovarian expression of the essential thioredoxin Deadhead (DHD) is critically regulated in Drosophila by the histone demethylase Lid and its partner, the histone deacetylase complex Sin3A/Rpd3, via yet unknown mechanisms. Here, we identified Snr1 and Mod(mdg4) as essential for dhd expression and investigated how these epigenomic effectors act with Lid and Sin3A to hyperactivate dhd. Using Cut&Run chromatin profiling with a dedicated data analysis procedure, we found that dhd is intriguingly embedded in an H3K27me3/H3K9me3-enriched mini-domain flanked by DNA regulatory elements, including a dhd promoter-proximal element essential for its expression. Surprisingly, Lid, Sin3a, Snr1 and Mod(mdg4) impact H3K27me3 and this regulatory element in distinct manners. However, we show that these effectors activate dhd independently of H3K27me3/H3K9me3, and that dhd remains silent in the absence of these marks. Together, our study demonstrates an atypical and critical role for chromatin regulators Lid, Sin3A, Snr1 and Mod(mdg4) to trigger tissue-specific hyperactivation within a unique heterochromatin mini-domain. Multicellular development depends on a tight control of gene expression in each cell type. This relies on the coordinated activities of nuclear proteins that interact with DNA or its histone scaffold to promote or restrict gene transcription. For example, we previously showed that the histone modifying enzymes Lid and Sin3A/Rpd3 are required in Drosophila ovaries for the massive expression of deadhead (dhd), a gene encoding for a thioredoxin that is essential for fertility. In this paper, we have further identified two additional dhd regulators, Snr1 and Mod(mdg4) and dissected the mechanism behind hyperactivation of this gene. Using the epigenomic profiling method Cut&Run with a dedicated data analysis approach, we unexpectedly found that dhd is embedded in an unusual chromatin mini-domain featuring repressive histone modifications H3K27me3 and H3K9me3 and flanked by two regulatory elements. However, we further showed that Lid, Sin3A, Snr1 and Mod(mdg4) behave like obligatory activators of dhd independently of this mini-domain. Our study unveils how multiple broad-acting epigenomic effectors operate in non-canonical manners to ensure a critical and specialized gene activation event. These findings challenge our knowledge on these regulatory mechanisms and their roles in development and pathology.
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Affiliation(s)
- Daniela Torres-Campana
- Laboratoire de Biologie et Modélisation de la Cellule, CNRS UMR5239, École Normale Supérieure de Lyon, University of Lyon, Lyon, France
| | - Béatrice Horard
- Laboratoire de Biologie et Modélisation de la Cellule, CNRS UMR5239, École Normale Supérieure de Lyon, University of Lyon, Lyon, France
| | - Sandrine Denaud
- Institute of Human Genetics, UMR 9002, CNRS, Université de Montpellier, Montpellier, France
| | - Gérard Benoit
- Laboratoire de Biologie et Modélisation de la Cellule, CNRS UMR5239, École Normale Supérieure de Lyon, University of Lyon, Lyon, France
| | - Benjamin Loppin
- Laboratoire de Biologie et Modélisation de la Cellule, CNRS UMR5239, École Normale Supérieure de Lyon, University of Lyon, Lyon, France
- * E-mail: (BL); (GAO)
| | - Guillermo A. Orsi
- Laboratoire de Biologie et Modélisation de la Cellule, CNRS UMR5239, École Normale Supérieure de Lyon, University of Lyon, Lyon, France
- * E-mail: (BL); (GAO)
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10
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Gibert JM, Peronnet F. The Paramount Role of Drosophila melanogaster in the Study of Epigenetics: From Simple Phenotypes to Molecular Dissection and Higher-Order Genome Organization. INSECTS 2021; 12:884. [PMID: 34680653 PMCID: PMC8537509 DOI: 10.3390/insects12100884] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 09/24/2021] [Accepted: 09/26/2021] [Indexed: 01/06/2023]
Abstract
Drosophila melanogaster has played a paramount role in epigenetics, the study of changes in gene function inherited through mitosis or meiosis that are not due to changes in the DNA sequence. By analyzing simple phenotypes, such as the bristle position or cuticle pigmentation, as read-outs of regulatory processes, the identification of mutated genes led to the discovery of major chromatin regulators. These are often conserved in distantly related organisms such as vertebrates or even plants. Many of them deposit, recognize, or erase post-translational modifications on histones (histone marks). Others are members of chromatin remodeling complexes that move, eject, or exchange nucleosomes. We review the role of D. melanogaster research in three epigenetic fields: Heterochromatin formation and maintenance, the repression of transposable elements by piRNAs, and the regulation of gene expression by the antagonistic Polycomb and Trithorax complexes. We then describe how genetic tools available in D. melanogaster allowed to examine the role of histone marks and show that some histone marks are dispensable for gene regulation, whereas others play essential roles. Next, we describe how D. melanogaster has been particularly important in defining chromatin types, higher-order chromatin structures, and their dynamic changes during development. Lastly, we discuss the role of epigenetics in a changing environment.
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Affiliation(s)
- Jean-Michel Gibert
- Centre National de la Recherche Scientifique (CNRS), Laboratoire de Biologie du Développement (LBD), Institut de Biologie Paris Seine (IBPS), Sorbonne Université, 75005 Paris, France
| | - Frédérique Peronnet
- Centre National de la Recherche Scientifique (CNRS), Laboratoire de Biologie du Développement (LBD), Institut de Biologie Paris Seine (IBPS), Sorbonne Université, 75005 Paris, France
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11
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The Sound of Silence: How Silenced Chromatin Orchestrates the Repair of Double-Strand Breaks. Genes (Basel) 2021; 12:genes12091415. [PMID: 34573397 PMCID: PMC8467445 DOI: 10.3390/genes12091415] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/07/2021] [Accepted: 09/13/2021] [Indexed: 12/29/2022] Open
Abstract
The eukaryotic nucleus is continuously being exposed to endogenous and exogenous sources that cause DNA breaks, whose faithful repair requires the activity of dedicated nuclear machineries. DNA is packaged into a variety of chromatin domains, each characterized by specific molecular properties that regulate gene expression and help maintain nuclear structure. These different chromatin environments each demand a tailored response to DNA damage. Silenced chromatin domains in particular present a major challenge to the cell’s DNA repair machinery due to their specific biophysical properties and distinct, often repetitive, DNA content. To this end, we here discuss the interplay between silenced chromatin domains and DNA damage repair, specifically double-strand breaks, and how these processes help maintain genome stability.
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12
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Mechanistic insights into KDM4A driven genomic instability. Biochem Soc Trans 2021; 49:93-105. [PMID: 33492339 PMCID: PMC7925003 DOI: 10.1042/bst20191219] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 12/11/2020] [Accepted: 12/15/2020] [Indexed: 12/19/2022]
Abstract
Alterations in global epigenetic signatures on chromatin are well established to contribute to tumor initiation and progression. Chromatin methylation status modulates several key cellular processes that maintain the integrity of the genome. KDM4A, a demethylase that belongs to the Fe-II dependent dioxygenase family that uses α-ketoglutarate and molecular oxygen as cofactors, is overexpressed in several cancers and is associated with an overall poor prognosis. KDM4A demethylates lysine 9 (H3K9me2/3) and lysine 36 (H3K36me3) methyl marks on histone H3. Given the complexity that exists with these marks on chromatin and their effects on transcription and proliferation, it naturally follows that demethylation serves an equally important role in these cellular processes. In this review, we highlight the role of KDM4A in transcriptional modulation, either dependent or independent of its enzymatic activity, arising from the amplification of this demethylase in cancer. KDM4A modulates re-replication of distinct genomic loci, activates cell cycle inducers, and represses proteins involved in checkpoint control giving rise to proliferative damage, mitotic disturbances and chromosomal breaks, ultimately resulting in genomic instability. In parallel, emerging evidence of non-nuclear substrates of epigenetic modulators emphasize the need to investigate the role of KDM4A in regulating non-nuclear substrates and evaluate their contribution to genomic instability in this context. The existence of promising KDM-specific inhibitors makes these demethylases an attractive target for therapeutic intervention in cancers.
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13
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Meyer-Nava S, Nieto-Caballero VE, Zurita M, Valadez-Graham V. Insights into HP1a-Chromatin Interactions. Cells 2020; 9:E1866. [PMID: 32784937 PMCID: PMC7465937 DOI: 10.3390/cells9081866] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/18/2020] [Accepted: 07/21/2020] [Indexed: 12/17/2022] Open
Abstract
Understanding the packaging of DNA into chromatin has become a crucial aspect in the study of gene regulatory mechanisms. Heterochromatin establishment and maintenance dynamics have emerged as some of the main features involved in genome stability, cellular development, and diseases. The most extensively studied heterochromatin protein is HP1a. This protein has two main domains, namely the chromoshadow and the chromodomain, separated by a hinge region. Over the years, several works have taken on the task of identifying HP1a partners using different strategies. In this review, we focus on describing these interactions and the possible complexes and subcomplexes associated with this critical protein. Characterization of these complexes will help us to clearly understand the implications of the interactions of HP1a in heterochromatin maintenance, heterochromatin dynamics, and heterochromatin's direct relationship to gene regulation and chromatin organization.
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Affiliation(s)
| | | | | | - Viviana Valadez-Graham
- Instituto de Biotecnología, Departamento de Genética del Desarrollo y Fisiología Molecular, Universidad Nacional Autónoma de México, Cuernavaca Morelos 62210, Mexico; (S.M.-N.); (V.E.N.-C.); (M.Z.)
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14
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Meyer-Nava S, Torres A, Zurita M, Valadez-Graham V. Molecular effects of dADD1 misexpression in chromatin organization and transcription. BMC Mol Cell Biol 2020; 21:17. [PMID: 32293240 PMCID: PMC7092677 DOI: 10.1186/s12860-020-00257-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 03/04/2020] [Indexed: 12/14/2022] Open
Abstract
Background dADD1 and dXNP proteins are the orthologs in Drosophila melanogaster of the ADD and SNF2 domains, respectively, of the ATRX vertebrate’s chromatin remodeler, they suppress position effect variegation phenotypes and participate in heterochromatin maintenance. Results We performed a search in human cancer databases and found that ATRX protein levels were elevated in more than 4.4% of the samples analyzed. Using the Drosophila model, we addressed the effects of over and under-expression of dADD1 proteins in polytene cells. Elevated levels of dADD1 in fly tissues caused different phenotypes, such as chromocenter disruption and loss of banding pattern at the chromosome arms. Analyses of the heterochromatin maintenance protein HP1a, the dXNP ATPase and the histone post-translational modification H3K9me3 revealed changes in their chromatin localization accompanied by mild transcriptional defects of genes embedded in heterochromatic regions. Furthermore, the expression of heterochromatin embedded genes in null dadd1 organisms is lower than in the wild-type conditions. Conclusion These data indicate that dADD1 overexpression induces chromatin changes, probably affecting the stoichiometry of HP1a containing complexes that lead to transcriptional and architectural changes. Our results place dADD1 proteins as important players in the maintenance of chromatin architecture and heterochromatic gene expression.
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Affiliation(s)
- Silvia Meyer-Nava
- Instituto de Biotecnología. Universidad Nacional Autónoma de México, Campus Morelos, Av. Universidad 2001, C.P, 62210, Cuernavaca, Morelos, Mexico
| | - Amada Torres
- Instituto de Biotecnología. Universidad Nacional Autónoma de México, Campus Morelos, Av. Universidad 2001, C.P, 62210, Cuernavaca, Morelos, Mexico
| | - Mario Zurita
- Instituto de Biotecnología. Universidad Nacional Autónoma de México, Campus Morelos, Av. Universidad 2001, C.P, 62210, Cuernavaca, Morelos, Mexico
| | - Viviana Valadez-Graham
- Instituto de Biotecnología. Universidad Nacional Autónoma de México, Campus Morelos, Av. Universidad 2001, C.P, 62210, Cuernavaca, Morelos, Mexico.
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15
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Ninova M, Chen YCA, Godneeva B, Rogers AK, Luo Y, Fejes Tóth K, Aravin AA. Su(var)2-10 and the SUMO Pathway Link piRNA-Guided Target Recognition to Chromatin Silencing. Mol Cell 2019; 77:556-570.e6. [PMID: 31901446 DOI: 10.1016/j.molcel.2019.11.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 06/11/2019] [Accepted: 11/08/2019] [Indexed: 01/14/2023]
Abstract
Regulation of transcription is the main mechanism responsible for precise control of gene expression. Whereas the majority of transcriptional regulation is mediated by DNA-binding transcription factors that bind to regulatory gene regions, an elegant alternative strategy employs small RNA guides, Piwi-interacting RNAs (piRNAs) to identify targets of transcriptional repression. Here, we show that in Drosophila the small ubiquitin-like protein SUMO and the SUMO E3 ligase Su(var)2-10 are required for piRNA-guided deposition of repressive chromatin marks and transcriptional silencing of piRNA targets. Su(var)2-10 links the piRNA-guided target recognition complex to the silencing effector by binding the piRNA/Piwi complex and inducing SUMO-dependent recruitment of the SetDB1/Wde histone methyltransferase effector. We propose that in Drosophila, the nuclear piRNA pathway has co-opted a conserved mechanism of SUMO-dependent recruitment of the SetDB1/Wde chromatin modifier to confer repression of genomic parasites.
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Affiliation(s)
- Maria Ninova
- California Institute of Technology, Division of Biology and Biological Engineering, 147-75, Pasadena, CA 91125, USA
| | - Yung-Chia Ariel Chen
- California Institute of Technology, Division of Biology and Biological Engineering, 147-75, Pasadena, CA 91125, USA
| | - Baira Godneeva
- California Institute of Technology, Division of Biology and Biological Engineering, 147-75, Pasadena, CA 91125, USA; Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Alicia K Rogers
- California Institute of Technology, Division of Biology and Biological Engineering, 147-75, Pasadena, CA 91125, USA
| | - Yicheng Luo
- California Institute of Technology, Division of Biology and Biological Engineering, 147-75, Pasadena, CA 91125, USA
| | - Katalin Fejes Tóth
- California Institute of Technology, Division of Biology and Biological Engineering, 147-75, Pasadena, CA 91125, USA.
| | - Alexei A Aravin
- California Institute of Technology, Division of Biology and Biological Engineering, 147-75, Pasadena, CA 91125, USA.
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16
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Meisel RP, Delclos PJ, Wexler JR. The X chromosome of the German cockroach, Blattella germanica, is homologous to a fly X chromosome despite 400 million years divergence. BMC Biol 2019; 17:100. [PMID: 31806031 PMCID: PMC6894488 DOI: 10.1186/s12915-019-0721-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 11/11/2019] [Indexed: 12/30/2022] Open
Abstract
Background Sex chromosome evolution is a dynamic process that can proceed at varying rates across lineages. For example, different chromosomes can be sex-linked between closely related species, whereas other sex chromosomes have been conserved for > 100 million years. Cases of long-term sex chromosome conservation could be informative of factors that constrain sex chromosome evolution. Cytological similarities between the X chromosomes of the German cockroach (Blattella germanica) and most flies suggest that they may be homologous—possibly representing an extreme case of long-term conservation. Results To test the hypothesis that the cockroach and fly X chromosomes are homologous, we analyzed whole-genome sequence data from cockroaches. We found evidence in both sequencing coverage and heterozygosity that a significant excess of the same genes are on both the cockroach and fly X chromosomes. We also present evidence that the candidate X-linked cockroach genes may be dosage compensated in hemizygous males. Consistent with this hypothesis, three regulators of transcription and chromatin on the fly X chromosome are conserved in the cockroach genome. Conclusions Our results support our hypothesis that the German cockroach shares the same X chromosome as most flies. This may represent the convergent evolution of the X chromosome in the lineages leading to cockroaches and flies. Alternatively, the common ancestor of most insects may have had an X chromosome that resembled the extant cockroach and fly X. Cockroaches and flies diverged ∼ 400 million years ago, which would be the longest documented conservation of a sex chromosome. Cockroaches and flies have different mechanisms of sex determination, raising the possibility that the X chromosome was conserved despite the evolution of the sex determination pathway.
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Affiliation(s)
- Richard P Meisel
- Department of Biology and Biochemistry, University of Houston, 3455 Cullen Blvd., Houston, 77204, TX, USA.
| | - Pablo J Delclos
- Department of Biology and Biochemistry, University of Houston, 3455 Cullen Blvd., Houston, 77204, TX, USA
| | - Judith R Wexler
- Department of Ecology and Evolution, University of California, Davis, One Shields Ave, Davis, 95616, CA, USA.,Department of Entomology, University of Maryland, 4112 Plant Sciences Building, College Park, 20742, MD, USA
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17
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Wang SH, Elgin SCR. The impact of genetic background and cell lineage on the level and pattern of gene expression in position effect variegation. Epigenetics Chromatin 2019; 12:70. [PMID: 31722719 PMCID: PMC6852933 DOI: 10.1186/s13072-019-0314-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Accepted: 10/28/2019] [Indexed: 01/17/2023] Open
Abstract
Background Chromatin-based transcriptional silencing is often described as a stochastic process, largely because of the mosaic expression observed in position effect variegation (PEV), where a euchromatic reporter gene is silenced in some cells as a consequence of juxtaposition with heterochromatin. High levels of variation in PEV phenotypes are commonly observed in reporter stocks. To ascertain whether background mutations are the major contributors to this variation, we asked how much of the variation is determined by genetic variants segregating in the population, examining both the level and pattern of expression using the fruit fly, Drosophila melanogaster, as the model. Results Using selective breeding of a fourth chromosome PEV reporter line, 39C-12, we isolated two inbred lines exhibiting contrasting degrees of variegation (A1: low expression, D1: high expression). Within each inbred population, remarkable similarity is observed in the degree of variegation: 90% of the variation between the two inbred lines in the degree of silencing can be explained by genotype. Further analyses suggest that this result reflects the combined effect of multiple independent trans-acting loci. While the initial observations are based on a PEV phenotype scored in the fly eye (hsp70-white reporter), similar degrees of silencing were observed using a beta-gal reporter scored across the whole fly. Further, the pattern of variegation becomes almost identical within each inbred line; significant pigment enrichment in the same quadrant of the eye was found for both A1 and D1 lines despite different degrees of expression. Conclusions The results indicate that background genetic variants play the major role in determining the variable degrees of PEV commonly observed in laboratory stocks. Interestingly, not only does the degree of variegation become consistent in inbred lines, the patterns of variegation also appear similar. Combining these observations with the spreading model for local heterochromatin formation, we propose an augmented stochastic model to describe PEV in which the genetic background drives the overall level of silencing, working with the cell lineage-specific regulatory environment to determine the on/off probability at the reporter locus in each cell. This model acknowledges cell type-specific events in the context of broader genetic impacts on heterochromatin formation.
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Affiliation(s)
- Sidney H Wang
- Center for Human Genetics, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX, USA.
| | - Sarah C R Elgin
- Department of Biology, Washington University, St Louis, MO, 63130, USA.
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18
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Benner L, Castro EA, Whitworth C, Venken KJT, Yang H, Fang J, Oliver B, Cook KR, Lerit DA. Drosophila Heterochromatin Stabilization Requires the Zinc-Finger Protein Small Ovary. Genetics 2019; 213:877-895. [PMID: 31558581 PMCID: PMC6827387 DOI: 10.1534/genetics.119.302590] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 09/21/2019] [Indexed: 02/04/2023] Open
Abstract
Heterochromatin-mediated repression is essential for controlling the expression of transposons and for coordinated cell type-specific gene regulation. The small ovary (sov) locus was identified in a screen for female-sterile mutations in Drosophila melanogaster, and mutants show dramatic ovarian morphogenesis defects. We show that the null sov phenotype is lethal and map the locus to the uncharacterized gene CG14438, which encodes a nuclear zinc-finger protein that colocalizes with the essential Heterochromatin Protein 1 (HP1a). We demonstrate Sov functions to repress inappropriate gene expression in the ovary, silence transposons, and suppress position-effect variegation in the eye, suggesting a central role in heterochromatin stabilization.
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Affiliation(s)
- Leif Benner
- Section of Developmental Genomics, Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218
| | - Elias A Castro
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Cale Whitworth
- Section of Developmental Genomics, Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Koen J T Venken
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology
- McNair Medical Institute at the Robert and Janice McNair Foundation
- Dan L. Duncan Cancer Center, Center for Drug Discovery
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Haiwang Yang
- Section of Developmental Genomics, Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Junnan Fang
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Brian Oliver
- Section of Developmental Genomics, Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Kevin R Cook
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Dorothy A Lerit
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322
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19
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Ninova M, Fejes Tóth K, Aravin AA. The control of gene expression and cell identity by H3K9 trimethylation. Development 2019; 146:dev181180. [PMID: 31540910 PMCID: PMC6803365 DOI: 10.1242/dev.181180] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Histone 3 lysine 9 trimethylation (H3K9me3) is a conserved histone modification that is best known for its role in constitutive heterochromatin formation and the repression of repetitive DNA elements. More recently, it has become evident that H3K9me3 is also deposited at certain loci in a tissue-specific manner and plays important roles in regulating cell identity. Notably, H3K9me3 can repress genes encoding silencing factors, pointing to a fundamental principle of repressive chromatin auto-regulation. Interestingly, recent studies have shown that H3K9me3 deposition requires protein SUMOylation in different contexts, suggesting that the SUMO pathway functions as an important module in gene silencing and heterochromatin formation. In this Review, we discuss the role of H3K9me3 in gene regulation in various systems and the molecular mechanisms that guide the silencing machinery to target loci.
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Affiliation(s)
- Maria Ninova
- California Institute of Technology, Division of Biology and Biological Engineering, 147-75, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Katalin Fejes Tóth
- California Institute of Technology, Division of Biology and Biological Engineering, 147-75, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Alexei A Aravin
- California Institute of Technology, Division of Biology and Biological Engineering, 147-75, 1200 East California Boulevard, Pasadena, CA 91125, USA
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20
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Sidorenko DS, Sidorenko IA, Zykova TY, Goncharov FP, Larsson J, Zhimulev IF. Molecular and genetic organization of bands and interbands in the dot chromosome of Drosophila melanogaster. Chromosoma 2019; 128:97-117. [PMID: 31041520 PMCID: PMC6536484 DOI: 10.1007/s00412-019-00703-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 01/09/2019] [Accepted: 04/02/2019] [Indexed: 12/24/2022]
Abstract
The fourth chromosome smallest in the genome of Drosophila melanogaster differs from other chromosomes in many ways. It has high repeat density in conditions of a large number of active genes. Gray bands represent a significant part of this polytene chromosome. Specific proteins including HP1a, POF, and dSETDB1 establish the epigenetic state of this unique chromatin domain. In order to compare maps of localization of genes, bands, and chromatin types of the fourth chromosome, we performed FISH analysis of 38 probes chosen according to the model of four chromatin types. It allowed clarifying the dot chromosome cytological map consisting of 16 loose gray bands, 11 dense black bands, and 26 interbands. We described the relation between chromatin states and bands. Open aquamarine chromatin mostly corresponds to interbands and it contains 5'UTRs of housekeeping genes. Their coding parts are embedded in gray bands substantially composed of lazurite chromatin of intermediate compaction. Polygenic black bands contain most of dense ruby chromatin, and also some malachite and lazurite. Having an accurate map of the fourth chromosome bands and its correspondence to physical map, we found that DNase I hypersensitivity sites, ORC2 protein, and P-elements are mainly located in open aquamarine chromatin, while element 1360, characteristic of the fourth chromosome, occupies band chromatin types. POF and HP1a proteins providing special organization of this chromosome are mostly located in aquamarine and lazurite chromatin. In general, band organization of the fourth chromosome shares the features of the whole Drosophila genome.
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Affiliation(s)
- Darya S Sidorenko
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences, Lavrentiev Ave. 8/2, Novosibirsk, Russia, 630090
| | - Ivan A Sidorenko
- Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Tatyana Yu Zykova
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences, Lavrentiev Ave. 8/2, Novosibirsk, Russia, 630090
| | - Fedor P Goncharov
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences, Lavrentiev Ave. 8/2, Novosibirsk, Russia, 630090
| | - Jan Larsson
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Igor F Zhimulev
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences, Lavrentiev Ave. 8/2, Novosibirsk, Russia, 630090. .,Laboratory of structural, functional and comparative genomics of the Novosibirsk State University, Novosibirsk, Russia.
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21
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Seller CA, Cho CY, O'Farrell PH. Rapid embryonic cell cycles defer the establishment of heterochromatin by Eggless/SetDB1 in Drosophila. Genes Dev 2019; 33:403-417. [PMID: 30808658 PMCID: PMC6446540 DOI: 10.1101/gad.321646.118] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 01/14/2019] [Indexed: 12/15/2022]
Abstract
Acquisition of chromatin modifications during embryogenesis distinguishes different regions of an initially naïve genome. In many organisms, repetitive DNA is packaged into constitutive heterochromatin that is marked by di/trimethylation of histone H3K9 and the associated protein HP1a. These modifications enforce the unique epigenetic properties of heterochromatin. However, in the early Drosophila melanogaster embryo, the heterochromatin lacks these modifications, which appear only later, when rapid embryonic cell cycles slow down at the midblastula transition (MBT). Here we focus on the initial steps restoring heterochromatic modifications in the embryo. We describe the JabbaTrap, a technique for inactivating maternally provided proteins in embryos. Using the JabbaTrap, we reveal a major requirement for the methyltransferase Eggless/SetDB1 in the establishment of heterochromatin. In contrast, other methyltransferases contribute minimally. Live imaging reveals that endogenous Eggless gradually accumulates on chromatin in interphase but then dissociates in mitosis, and its accumulation must restart in the next cell cycle. Cell cycle slowing as the embryo approaches the MBT permits increasing accumulation and action of Eggless at its targets. Experimental manipulation of interphase duration shows that cell cycle speed regulates Eggless. We propose that developmental slowing of the cell cycle times embryonic heterochromatin formation.
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Affiliation(s)
- Charles A Seller
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94143, USA
| | - Chun-Yi Cho
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94143, USA
| | - Patrick H O'Farrell
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94143, USA
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22
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Masuko K, Fuse N, Komaba K, Katsuyama T, Nakajima R, Furuhashi H, Kurata S. winged eye Induces Transdetermination of Drosophila Imaginal Disc by Acting in Concert with a Histone Methyltransferase, Su(var)3-9. Cell Rep 2019; 22:206-217. [PMID: 29298422 DOI: 10.1016/j.celrep.2017.11.105] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 07/12/2017] [Accepted: 11/29/2017] [Indexed: 12/23/2022] Open
Abstract
Drosophila imaginal disc cells exhibit a remarkable ability to convert cell fates in response to various perturbations, a phenomenon called transdetermination (TD). We previously identified winged eye (wge) as a factor that induces eye-to-wing TD upon overexpression in eye imaginal discs, but the molecular mechanisms underlying TD have remained largely unclear. Here, we found that wge induces various histone modifications and enhances the methylation of Lys9 on histone H3 (H3K9), a feature of heterochromatin. A histone methyltransferase, Su(var)3-9, is required for wge-mediated H3K9 methylation and eye-to-wing TD. Su(var)3-9 is also required for classical wound-induced TD but not for normal development, suggesting its involvement in several types of imaginal disc TDs. Transcriptome analysis revealed that wge represses eye identity genes independently of Su(var)3-9 and activates TD-related genes by acting together with Su(var)3-9. These findings provide new insights into diverse types of chromatin regulation at progressive steps of cell-fate conversions.
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Affiliation(s)
- Keita Masuko
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Naoyuki Fuse
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Kanae Komaba
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Tomonori Katsuyama
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Rumi Nakajima
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Hirofumi Furuhashi
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Shoichiro Kurata
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan.
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23
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The Drosophila Dot Chromosome: Where Genes Flourish Amidst Repeats. Genetics 2019; 210:757-772. [PMID: 30401762 PMCID: PMC6218221 DOI: 10.1534/genetics.118.301146] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 08/17/2018] [Indexed: 11/18/2022] Open
Abstract
The F element of the Drosophila karyotype (the fourth chromosome in Drosophila melanogaster) is often referred to as the "dot chromosome" because of its appearance in a metaphase chromosome spread. This chromosome is distinct from other Drosophila autosomes in possessing both a high level of repetitious sequences (in particular, remnants of transposable elements) and a gene density similar to that found in the other chromosome arms, ∼80 genes distributed throughout its 1.3-Mb "long arm." The dot chromosome is notorious for its lack of recombination and is often neglected as a consequence. This and other features suggest that the F element is packaged as heterochromatin throughout. F element genes have distinct characteristics (e.g, low codon bias, and larger size due both to larger introns and an increased number of exons), but exhibit expression levels comparable to genes found in euchromatin. Mapping experiments show the presence of appropriate chromatin modifications for the formation of DNaseI hypersensitive sites and transcript initiation at the 5' ends of active genes, but, in most cases, high levels of heterochromatin proteins are observed over the body of these genes. These various features raise many interesting questions about the relationships of chromatin structures with gene and chromosome function. The apparent evolution of the F element as an autosome from an ancestral sex chromosome also raises intriguing questions. The findings argue that the F element is a unique chromosome that occupies its own space in the nucleus. Further study of the F element should provide new insights into chromosome structure and function.
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24
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Lee SK, Xue Y, Shen W, Zhang Y, Joo Y, Ahmad M, Chinen M, Ding Y, Ku WL, De S, Lehrmann E, Becker KG, Lei EP, Zhao K, Zou S, Sharov A, Wang W. Topoisomerase 3β interacts with RNAi machinery to promote heterochromatin formation and transcriptional silencing in Drosophila. Nat Commun 2018; 9:4946. [PMID: 30470739 PMCID: PMC6251927 DOI: 10.1038/s41467-018-07101-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 10/04/2018] [Indexed: 12/31/2022] Open
Abstract
Topoisomerases solve topological problems during DNA metabolism, but whether they participate in RNA metabolism remains unclear. Top3β represents a family of topoisomerases carrying activities for both DNA and RNA. Here we show that in Drosophila, Top3β interacts biochemically and genetically with the RNAi-induced silencing complex (RISC) containing AGO2, p68 RNA helicase, and FMRP. Top3β and RISC mutants are similarly defective in heterochromatin formation and transcriptional silencing by position-effect variegation assay. Moreover, both Top3β and AGO2 mutants exhibit reduced levels of heterochromatin protein HP1 in heterochromatin. Furthermore, expression of several genes and transposable elements in heterochromatin is increased in the Top3β mutant. Notably, Top3β mutants defective in either RNA binding or catalytic activity are deficient in promoting HP1 recruitment and silencing of transposable elements. Our data suggest that Top3β may act as an RNA topoisomerase in siRNA-guided heterochromatin formation and transcriptional silencing. Topoisomerases solve topological problems during DNA metabolism, but their role in RNA metabolism remains unclear. Here the authors provide evidence that in Drosophila, Topoisomerase 3β interacts biochemically and genetically with the RNAi-induced silencing complex (RISC) to promote heterochromatin formation and transcriptional silencing.
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Affiliation(s)
- Seung Kyu Lee
- Lab of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Yutong Xue
- Lab of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Weiping Shen
- Lab of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Yongqing Zhang
- Lab of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Yuyoung Joo
- Lab of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Muzammil Ahmad
- Lab of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Madoka Chinen
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive Kidney Diseases, Bethesda, MD, 20892, USA
| | - Yi Ding
- System Biology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Wai Lim Ku
- System Biology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Supriyo De
- Lab of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Elin Lehrmann
- Lab of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Kevin G Becker
- Lab of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Elissa P Lei
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive Kidney Diseases, Bethesda, MD, 20892, USA
| | - Keji Zhao
- System Biology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Sige Zou
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Alexei Sharov
- Lab of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Weidong Wang
- Lab of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA.
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The H3K9 methyltransferase SETDB1 maintains female identity in Drosophila germ cells. Nat Commun 2018; 9:4155. [PMID: 30297796 PMCID: PMC6175928 DOI: 10.1038/s41467-018-06697-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 09/19/2018] [Indexed: 12/17/2022] Open
Abstract
The preservation of germ cell sexual identity is essential for gametogenesis. Here we show that H3K9me3-mediated gene silencing is integral to female fate maintenance in Drosophila germ cells. Germ cell specific loss of the H3K9me3 pathway members, the H3K9 methyltransferase SETDB1, WDE, and HP1a, leads to ectopic expression of genes, many of which are normally expressed in testis. SETDB1 controls the accumulation of H3K9me3 over a subset of these genes without spreading into neighboring loci. At phf7, a regulator of male germ cell sexual fate, the H3K9me3 peak falls over the silenced testis-specific transcription start site. Furthermore, H3K9me3 recruitment to phf7 and repression of testis-specific transcription is dependent on the female sex determination gene Sxl. Thus, female identity is secured by an H3K9me3 epigenetic pathway in which Sxl is the upstream female-specific regulator, SETDB1 is the required chromatin writer, and phf7 is one of the critical SETDB1 target genes. Epigenetic regulation is critical for the maintenance of germ cell identity. Here the authors show that H3K9me3-mediated gene silencing is critical for repression of testis-specific transcription in Drosophila female germ cells, indicating H3K9me3 maintains female germ cell sexual identity.
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Song W, Zsindely N, Faragó A, Marsh JL, Bodai L. Systematic genetic interaction studies identify histone demethylase Utx as potential target for ameliorating Huntington's disease. Hum Mol Genet 2018; 27:649-666. [PMID: 29281014 PMCID: PMC5886221 DOI: 10.1093/hmg/ddx432] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 12/12/2017] [Accepted: 12/15/2017] [Indexed: 01/29/2023] Open
Abstract
Huntington's disease (HD) is a dominantly inherited neurodegenerative disease caused by alterations in the huntingtin gene (htt). Transcriptional dysregulation is an early event in HD progression. Protein acetylation and methylation particularly on histones regulates chromatin structure thereby preventing or facilitating transcription. Although protein acetylation has been found to affect HD symptoms, little is known about the potential role of protein methylation in HD pathology. In recent years, a series of proteins have been described that are responsible for methylating and demethylating histones as well as other proteins. We carried out systematic genetic interaction studies testing lysine and arginine methylases and demethylases in a Drosophila melanogaster HD model. We found that modulating methylation enzymes that typically affect histone positions H3K4, H3K36 or H3K79 had varying effects on HD pathology while modulating ones that typically affect constitutive heterochromatin marks at H3K9 and H4K20 generally had limited impact on HD pathology. In contrast, modulating enzymes acting on the facultative heterochromatin mark at H3K27 had specific effects on HD pathology, with reduction of the demethylase Utx rescuing HTT-induced pathology while reducing Polycomb Repressive Complex2 core methylase components led to more aggressive pathology. Further exploration of the mechanism underlying the methylation-specific interactions suggest that these lysine and arginine methylases and demethylases are likely exerting their influence through non-histone targets. These results highlight a novel therapeutic approach for HD in the form of Utx inhibition.
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Affiliation(s)
- Wan Song
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA 92697, USA
| | - Nóra Zsindely
- Department of Biochemistry and Molecular Biology, University of Szeged, 6726 Szeged, Hungary
| | - Anikó Faragó
- Department of Biochemistry and Molecular Biology, University of Szeged, 6726 Szeged, Hungary
- Doctoral School in Biology, Faculty of Science and Informatics, University of Szeged, 6726 Szeged, Hungary
| | - J Lawrence Marsh
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA 92697, USA
| | - László Bodai
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA 92697, USA
- Department of Biochemistry and Molecular Biology, University of Szeged, 6726 Szeged, Hungary
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Maksimov DA, Laktionov PP, Posukh OV, Belyakin SN, Koryakov DE. Genome-wide analysis of SU(VAR)3-9 distribution in chromosomes of Drosophila melanogaster. Chromosoma 2017; 127:85-102. [DOI: 10.1007/s00412-017-0647-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 09/18/2017] [Accepted: 09/19/2017] [Indexed: 02/07/2023]
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Hyun K, Jeon J, Park K, Kim J. Writing, erasing and reading histone lysine methylations. Exp Mol Med 2017; 49:e324. [PMID: 28450737 PMCID: PMC6130214 DOI: 10.1038/emm.2017.11] [Citation(s) in RCA: 694] [Impact Index Per Article: 99.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 12/20/2016] [Indexed: 02/08/2023] Open
Abstract
Histone modifications are key epigenetic regulatory features that have important roles in many cellular events. Lysine methylations mark various sites on the tail and globular domains of histones and their levels are precisely balanced by the action of methyltransferases ('writers') and demethylases ('erasers'). In addition, distinct effector proteins ('readers') recognize specific methyl-lysines in a manner that depends on the neighboring amino-acid sequence and methylation state. Misregulation of histone lysine methylation has been implicated in several cancers and developmental defects. Therefore, histone lysine methylation has been considered a potential therapeutic target, and clinical trials of several inhibitors of this process have shown promising results. A more detailed understanding of histone lysine methylation is necessary for elucidating complex biological processes and, ultimately, for developing and improving disease treatments. This review summarizes enzymes responsible for histone lysine methylation and demethylation and how histone lysine methylation contributes to various biological processes.
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Affiliation(s)
- Kwangbeom Hyun
- Laboratory of Eukaryotic Transcription, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Jongcheol Jeon
- Laboratory of Eukaryotic Transcription, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Kihyun Park
- Laboratory of Eukaryotic Transcription, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Jaehoon Kim
- Laboratory of Eukaryotic Transcription, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
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Penke TJR, McKay DJ, Strahl BD, Matera AG, Duronio RJ. Direct interrogation of the role of H3K9 in metazoan heterochromatin function. Genes Dev 2016; 30:1866-80. [PMID: 27566777 PMCID: PMC5024684 DOI: 10.1101/gad.286278.116] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 08/05/2016] [Indexed: 11/24/2022]
Abstract
A defining feature of heterochromatin is methylation of Lys9 of histone H3 (H3K9me), a binding site for heterochromatin protein 1 (HP1). Penke et al. generated and analyzed H3K9R mutant flies, separating the functions of H3K9 and nonhistone substrates of H3K9 methyltransferases. A defining feature of heterochromatin is methylation of Lys9 of histone H3 (H3K9me), a binding site for heterochromatin protein 1 (HP1). Although H3K9 methyltransferases and HP1 are necessary for proper heterochromatin structure, the specific contribution of H3K9 to heterochromatin function and animal development is unknown. Using our recently developed platform to engineer histone genes in Drosophila, we generated H3K9R mutant flies, separating the functions of H3K9 and nonhistone substrates of H3K9 methyltransferases. Nucleosome occupancy and HP1a binding at pericentromeric heterochromatin are markedly decreased in H3K9R mutants. Despite these changes in chromosome architecture, a small percentage of H3K9R mutants complete development. Consistent with this result, expression of most protein-coding genes, including those within heterochromatin, is similar between H3K9R and controls. In contrast, H3K9R mutants exhibit increased open chromatin and transcription from piRNA clusters and transposons, resulting in transposon mobilization. Hence, transposon silencing is a major developmental function of H3K9.
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Affiliation(s)
- Taylor J R Penke
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Daniel J McKay
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA; Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA; Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA; Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Brian D Strahl
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA; Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA; Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - A Gregory Matera
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA; Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA; Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA; Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA; Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Robert J Duronio
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA; Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA; Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA; Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA; Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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Abstract
Trans-inactivation is the repression of genes on a normal chromosome under the influence of a rearranged homologous chromosome demonstrating the position effect variegation (PEV). This phenomenon was studied in detail on the example of brownDominant allele causing the repression of wild-type brown gene on the opposite chromosome. We have investigated another trans-inactivation-inducing chromosome rearrangement, In(2)A4 inversion. In both cases, brownDominant and In(2)A4, the repression seems to be the result of dragging of the euchromatic region of the normal chromosome into the heterochromatic environment. It was found that cis-inactivation (classical PEV) and trans-inactivation show different patterns of distribution along the chromosome and respond differently to PEV modifying genes. It appears that the causative mechanism of trans-inactivation is de novo heterochromatin assembly on euchromatic sequences dragged into the heterochromatic nuclear compartment. Trans-inactivation turns out to be the result of a combination of heterochromatin-induced position effect and the somatic interphase chromosome pairing that is widespread in Diptera.
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Affiliation(s)
- Aleksei S Shatskikh
- a Department of Molecular Genetics of the Cell , Institute of Molecular Genetics, Russian Academy of Science , Moscow , Russia
| | - Yuriy A Abramov
- a Department of Molecular Genetics of the Cell , Institute of Molecular Genetics, Russian Academy of Science , Moscow , Russia
| | - Sergey A Lavrov
- a Department of Molecular Genetics of the Cell , Institute of Molecular Genetics, Russian Academy of Science , Moscow , Russia
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Heterochromatin-Associated Proteins HP1a and Piwi Collaborate to Maintain the Association of Achiasmate Homologs in Drosophila Oocytes. Genetics 2016; 203:173-89. [PMID: 26984058 DOI: 10.1534/genetics.115.186460] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 03/11/2016] [Indexed: 12/21/2022] Open
Abstract
Accurate segregation of homologous chromosomes during meiosis depends on their ability to remain physically connected throughout prophase I. For homologs that achieve a crossover, sister chromatid cohesion distal to the chiasma keeps them attached until anaphase I. However, in Drosophila melanogaster wild-type oocytes, chromosome 4 never recombines, and the X chromosome fails to cross over in 6-10% of oocytes. Proper segregation of these achiasmate homologs relies on their pericentric heterochromatin-mediated association, but the mechanism(s) underlying this attachment remains poorly understood. Using an inducible RNA interference (RNAi) strategy combined with fluorescence in situ hybridization (FISH) to monitor centromere proximal association of the achiasmate FM7a/X homolog pair, we asked whether specific heterochromatin-associated proteins are required for the association and proper segregation of achiasmate homologs in Drosophila oocytes. When we knock down HP1a, H3K9 methytransferases, or the HP1a binding partner Piwi during mid-prophase, we observe significant disruption of pericentric heterochromatin-mediated association of FM7a/X homologs. Furthermore, for both HP1a and Piwi knockdown oocytes, transgenic coexpression of the corresponding wild-type protein is able to rescue RNAi-induced defects, but expression of a mutant protein with a single amino acid change that disrupts the HP1a-Piwi interaction is unable to do so. We show that Piwi is stably bound to numerous sites along the meiotic chromosomes, including centromere proximal regions. In addition, reduction of HP1a or Piwi during meiotic prophase induces a significant increase in FM7a/X segregation errors. We present a speculative model outlining how HP1a and Piwi could collaborate to keep achiasmate chromosomes associated in a homology-dependent manner.
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Ozawa N, Furuhashi H, Masuko K, Numao E, Makino T, Yano T, Kurata S. Organ identity specification factor WGE localizes to the histone locus body and regulates histone expression to ensure genomic stability in Drosophila. Genes Cells 2016; 21:442-56. [PMID: 27145109 DOI: 10.1111/gtc.12354] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 01/28/2016] [Indexed: 12/19/2022]
Abstract
Over-expression of Winged-Eye (WGE) in the Drosophila eye imaginal disc induces an eye-to-wing transformation. Endogenous WGE is required for organ development, and wge-deficient mutants exhibit growth arrest at the larval stage, suggesting that WGE is critical for normal growth. The function of WGE, however, remains unclear. Here, we analyzed the subcellular localization of WGE to gain insight into its endogenous function. Immunostaining showed that WGE localized to specific nuclear foci called the histone locus body (HLB), an evolutionarily conserved nuclear body required for S phase-specific histone mRNA production. Histone mRNA levels and protein levels in cytosolic fractions were aberrantly up-regulated in wge mutant larva, suggesting a role for WGE in regulating histone gene expression. Genetic analyses showed that wge suppresses position-effect variegation, and that WGE and a HLB component Mute appears to be synergistically involved in heterochromatin formation. Further supporting a role in chromatin regulation, wge-deficient mutants showed derepression of retrotransposons and increased γH2Av signals, a DNA damage marker. These findings suggest that WGE is a component of HLB in Drosophila with a role in heterochromatin formation and transposon silencing. We propose that WGE at HLB contributes to genomic stability and development by regulating heterochromatin structure via histone gene regulation.
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Affiliation(s)
- Nao Ozawa
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
| | - Hirofumi Furuhashi
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
| | - Keita Masuko
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
| | - Eriko Numao
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
| | - Takashi Makino
- Graduate School of Life Sciences, Tohoku University, Sendai, 980-8578, Japan
| | - Tamaki Yano
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
| | - Shoichiro Kurata
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan
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Timms RT, Tchasovnikarova IA, Lehner PJ. Position-effect variegation revisited: HUSHing up heterochromatin in human cells. Bioessays 2016; 38:333-43. [DOI: 10.1002/bies.201500184] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Richard T. Timms
- Department of Medicine, Cambridge Institute for Medical Research; Addenbrooke's Hospital; Cambridge UK
| | - Iva A. Tchasovnikarova
- Department of Medicine, Cambridge Institute for Medical Research; Addenbrooke's Hospital; Cambridge UK
| | - Paul J. Lehner
- Department of Medicine, Cambridge Institute for Medical Research; Addenbrooke's Hospital; Cambridge UK
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Sienski G, Batki J, Senti KA, Dönertas D, Tirian L, Meixner K, Brennecke J. Silencio/CG9754 connects the Piwi-piRNA complex to the cellular heterochromatin machinery. Genes Dev 2015; 29:2258-71. [PMID: 26494711 PMCID: PMC4647559 DOI: 10.1101/gad.271908.115] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 10/05/2015] [Indexed: 11/24/2022]
Abstract
In this study, Sienski et al. characterize CG9754/Silencio as an essential piRNA pathway factor that is required for Piwi's nuclear function in guiding the transcriptional silencing of transposons. These results provide novel insight into the transcriptional silencing process downstream from Piwi and the regulation of piRNA-guided heterochromatin formation. The repression of transposable elements in eukaryotes often involves their transcriptional silencing via targeted chromatin modifications. In animal gonads, nuclear Argonaute proteins of the PIWI clade complexed with small guide RNAs (piRNAs) serve as sequence specificity determinants in this process. How binding of nuclear PIWI–piRNA complexes to nascent transcripts orchestrates heterochromatin formation and transcriptional silencing is unknown. Here, we characterize CG9754/Silencio as an essential piRNA pathway factor that is required for Piwi-mediated transcriptional silencing in Drosophila. Ectopic targeting of Silencio to RNA or DNA is sufficient to elicit silencing independently of Piwi and known piRNA pathway factors. Instead, Silencio requires the H3K9 methyltransferase Eggless/SetDB1 for its silencing ability. In agreement with this, SetDB1, but not Su(var)3-9, is required for Piwi-mediated transcriptional silencing genome-wide. Due to its interaction with the target-engaged Piwi–piRNA complex, we suggest that Silencio acts as linker between the sequence specificity factor Piwi and the cellular heterochromatin machinery.
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Affiliation(s)
- Grzegorz Sienski
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Julia Batki
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Kirsten-André Senti
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Derya Dönertas
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Laszlo Tirian
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Katharina Meixner
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Julius Brennecke
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), 1030 Vienna, Austria
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35
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Alagoz M, Katsuki Y, Ogiwara H, Ogi T, Shibata A, Kakarougkas A, Jeggo P. SETDB1, HP1 and SUV39 promote repositioning of 53BP1 to extend resection during homologous recombination in G2 cells. Nucleic Acids Res 2015. [PMID: 26206670 PMCID: PMC4652757 DOI: 10.1093/nar/gkv722] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recent studies have shown that homologous recombination (HR) requires chromatin repression as well as relaxation at DNA double strand breaks (DSBs). HP1 and SUV39H1/2 are repressive factors essential for HR. Here, we identify SETDB1 as an additional compacting factor promoting HR. Depletion of HP1, SUV39, SETDB1 or BRCA1 confer identical phenotypes. The repressive factors, like BRCA1, are dispensable for the initiation of resection but promote the extension step causing diminished RPA or RAD51 foci and HR in irradiated G2 cells. Depletion of the compacting factors does not inhibit BRCA1 recruitment but at 8 h post IR, BRCA1 foci are smaller and aberrantly positioned compared to control cells. BRCA1 promotes 53BP1 repositioning to the periphery of enlarged foci and formation of a devoid core with BRCA1 becoming enlarged and localized internally to 53BP1. Depletion of the compacting factors precludes these changes at irradiation-induced foci. Thus, the repressive factors are required for BRCA1 function in promoting the repositioning of 53BP1 during HR. Additionally, depletion of these repressive factors in undamaged cells causes diminished sister chromatid association at centromeric sequences. We propose a model for how these findings may be functionally linked.
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Affiliation(s)
- Meryem Alagoz
- University of Sussex Genome Damage and Stability Centre, East Sussex, BN19RQ, UK
| | - Yoko Katsuki
- University of Sussex Genome Damage and Stability Centre, East Sussex, BN19RQ, UK
| | - Hideaki Ogiwara
- Division of Genome Biology, National Cancer Centre Japan Research Institute, Tokyo, 104-0045, Japan
| | - Tomoo Ogi
- Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, 852-8523, Japan
| | - Atsushi Shibata
- University of Sussex Genome Damage and Stability Centre, East Sussex, BN19RQ, UK
| | - Andreas Kakarougkas
- University of Sussex Genome Damage and Stability Centre, East Sussex, BN19RQ, UK Department of Biology, School of Sciences and Engineering, The American University in Cairo, New Cairo, 11835, Egypt
| | - Penny Jeggo
- University of Sussex Genome Damage and Stability Centre, East Sussex, BN19RQ, UK
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Mozzetta C, Pontis J, Ait-Si-Ali S. Functional Crosstalk Between Lysine Methyltransferases on Histone Substrates: The Case of G9A/GLP and Polycomb Repressive Complex 2. Antioxid Redox Signal 2015; 22:1365-81. [PMID: 25365549 PMCID: PMC4432786 DOI: 10.1089/ars.2014.6116] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
SIGNIFICANCE Methylation of histone H3 on lysine 9 and 27 (H3K9 and H3K27) are two epigenetic modifications that have been linked to several crucial biological processes, among which are transcriptional silencing and cell differentiation. RECENT ADVANCES Deposition of these marks is catalyzed by H3K9 lysine methyltransferases (KMTs) and polycomb repressive complex 2, respectively. Increasing evidence is emerging in favor of a functional crosstalk between these two major KMT families. CRITICAL ISSUES Here, we review the current knowledge on the mechanisms of action and function of these enzymes, with particular emphasis on their interplay in the regulation of chromatin states and biological processes. We outline their crucial roles played in tissue homeostasis, by controlling the fate of embryonic and tissue-specific stem cells, highlighting how their deregulation is often linked to the emergence of a number of malignancies and neurological disorders. FUTURE DIRECTIONS Histone methyltransferases are starting to be tested as drug targets. A new generation of highly selective chemical inhibitors is starting to emerge. These hold great promise for a rapid translation of targeting epigenetic drugs into clinical practice for a number of aggressive cancers and neurological disorders.
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Affiliation(s)
- Chiara Mozzetta
- Laboratoire Epigénétique et Destin Cellulaire, UMR7216, Centre National de la Recherche Scientifique CNRS, Université Paris Diderot , Sorbonne Paris Cité, Paris, France
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Merkling SH, Bronkhorst AW, Kramer JM, Overheul GJ, Schenck A, Van Rij RP. The epigenetic regulator G9a mediates tolerance to RNA virus infection in Drosophila. PLoS Pathog 2015; 11:e1004692. [PMID: 25880195 PMCID: PMC4399909 DOI: 10.1371/journal.ppat.1004692] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 01/21/2015] [Indexed: 01/01/2023] Open
Abstract
Little is known about the tolerance mechanisms that reduce the negative effects of microbial infection on host fitness. Here, we demonstrate that the histone H3 lysine 9 methyltransferase G9a regulates tolerance to virus infection by shaping the response of the evolutionary conserved Jak-Stat pathway in Drosophila. G9a-deficient mutants are more sensitive to RNA virus infection and succumb faster to infection than wild-type controls, which was associated with strongly increased Jak-Stat dependent responses, but not with major differences in viral load. Genetic experiments indicate that hyperactivated Jak-Stat responses are associated with early lethality in virus-infected flies. Our results identify an essential epigenetic mechanism underlying tolerance to virus infection. Multicellular organisms deploy various strategies to fight microbial infections. Invading pathogens may be eradicated directly by antimicrobial effectors of the immune system. Another strategy consists of increasing the tolerance of the host to infection, for example, by limiting the adverse effects of the immune response. The molecular mechanisms underlying this novel concept remain largely uncharacterized. Here, we demonstrate that the epigenetic regulator G9a mediates tolerance to virus infection in Drosophila. We found that G9a-deficient flies succumb faster than control flies to infection with RNA viruses, but that the viral burden did not significantly differ. Unexpectedly, mutant flies express higher levels of genes that are regulated by the Jak-Stat signaling pathway, which in other studies was found to be important for antiviral defense. Exploiting the genetic toolbox in Drosophila, we demonstrate that Jak-Stat hyperactivation induces early mortality after virus infection. Precise control of immune pathways is essential to ensure efficient immunity, while preventing damage due to excessive immune responses. Our results indicate that G9a, an epigenetic modifier, dampens Jak-Stat responses to prevent immunopathology. Therefore, we propose epigenetic regulation of immunity as a new paradigm for disease tolerance.
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Affiliation(s)
- Sarah H. Merkling
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Alfred W. Bronkhorst
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jamie M. Kramer
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Gijs J. Overheul
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Annette Schenck
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ronald P. Van Rij
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
- * E-mail:
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38
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Cryderman DE, Vitalini MW, Wallrath LL. Heterochromatin protein 1a is required for an open chromatin structure. Transcription 2014; 2:95-99. [PMID: 21468237 DOI: 10.4161/trns.2.2.14687] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 12/30/2010] [Accepted: 12/31/2010] [Indexed: 01/03/2023] Open
Abstract
The Drosophila melanogaster fourth chromosome contains interspersed domains of active and repressive chromatin. We investigated a stock harboring a silenced transgene inserted into Dyrk3 and near Caps-two expressed genes on chromosome four. In an HP1a-deficient background, transgene expression was activated while, paradoxically, expression of Dyrk3 and Caps was reduced. We found that the promoters of Dyrk3 and Caps contained DNase I hypersensitive sites but also possessed methylated histone H3 and HP1a, marks of repressive chromatin. In HP1a-deficient flies, the Dyrk3 and Caps promoters displayed diminished accessibility to nuclease digestion, revealing a surprising role for HP1a in opening chromatin.
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Alekseyenko AA, Gorchakov AA, Zee BM, Fuchs SM, Kharchenko PV, Kuroda MI. Heterochromatin-associated interactions of Drosophila HP1a with dADD1, HIPP1, and repetitive RNAs. Genes Dev 2014; 28:1445-60. [PMID: 24990964 PMCID: PMC4083088 DOI: 10.1101/gad.241950.114] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Heterochromatin protein 1 (HP1a) plays conserved roles in gene silencing and heterochromatin and is also implicated in transcription, DNA replication, and repair. Using BioTAP-XL mass spectrometry and sequencing across multiple life stages of Drosophila, Alekseyenko et al. identify HP1a chromatin-associated protein and RNA interactions. They discover 13 novel candidates among the top interactions. Furthermore, HP1a selectively associates with a broad set of RNAs transcribed from repetitive regions. The validation of several novel HP1a protein interactors reveals new HP1a links to chromatin organization and function. Heterochromatin protein 1 (HP1a) has conserved roles in gene silencing and heterochromatin and is also implicated in transcription, DNA replication, and repair. Here we identify chromatin-associated protein and RNA interactions of HP1a by BioTAP-XL mass spectrometry and sequencing from Drosophila S2 cells, embryos, larvae, and adults. Our results reveal an extensive list of known and novel HP1a-interacting proteins, of which we selected three for validation. A strong novel interactor, dADD1 (Drosophila ADD1) (CG8290), is highly enriched in heterochromatin, harbors an ADD domain similar to human ATRX, displays selective binding to H3K9me2 and H3K9me3, and is a classic genetic suppressor of position-effect variegation. Unexpectedly, a second hit, HIPP1 (HP1 and insulator partner protein-1) (CG3680), is strongly connected to CP190-related complexes localized at putative insulator sequences throughout the genome in addition to its colocalization with HP1a in heterochromatin. A third interactor, the histone methyltransferase MES-4, is also enriched in heterochromatin. In addition to these protein–protein interactions, we found that HP1a selectively associated with a broad set of RNAs transcribed from repetitive regions. We propose that this rich network of previously undiscovered interactions will define how HP1a complexes perform their diverse functions in cells and developing organisms.
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Affiliation(s)
- Artyom A Alekseyenko
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Andrey A Gorchakov
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA; Institute of Molecular and Cellular Biology, Novosibirsk 630090, Russia
| | - Barry M Zee
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Stephen M Fuchs
- Department of Biology, Tufts University, Medford, Massachusetts 02155, USA
| | - Peter V Kharchenko
- Center for Biomedical Informatics, Harvard Medical School, Boston, Massachusetts 02115, USA; Hematology/Oncology Program, Children's Hospital, Boston, Massachusetts 02115, USA
| | - Mitzi I Kuroda
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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Molla-Herman A, Matias NR, Huynh JR. Chromatin modifications regulate germ cell development and transgenerational information relay. CURRENT OPINION IN INSECT SCIENCE 2014; 1:10-18. [PMID: 32846502 DOI: 10.1016/j.cois.2014.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 04/23/2014] [Accepted: 04/23/2014] [Indexed: 06/11/2023]
Abstract
Germ cells transmit genetic, cytoplasmic and epigenetic information to the next generation. Recent reports describe the importance of chromatin modifiers and small RNAs for germ cells development in Drosophila. We also review exciting progress in our understanding of piRNAs functions, which demonstrate that this class of small RNAs is both an adaptive and inheritable epigenetic memory.
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Affiliation(s)
- Anahi Molla-Herman
- Department of Genetics and Developmental Biology, Institut Curie, Paris, France; CNRS UMR3215, Inserm U934, F-75248 Paris, France
| | - Neuza R Matias
- Department of Genetics and Developmental Biology, Institut Curie, Paris, France; CNRS UMR3215, Inserm U934, F-75248 Paris, France
| | - Jean-René Huynh
- Department of Genetics and Developmental Biology, Institut Curie, Paris, France; CNRS UMR3215, Inserm U934, F-75248 Paris, France.
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41
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Sentmanat M, Wang SH, Elgin SCR. Targeting heterochromatin formation to transposable elements in Drosophila: potential roles of the piRNA system. BIOCHEMISTRY (MOSCOW) 2014; 78:562-71. [PMID: 23980883 DOI: 10.1134/s0006297913060023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Successful heterochromatin formation is critical for genome stability in eukaryotes, both to maintain structures needed for mitosis and meiosis and to silence potentially harmful transposable elements. Conversely, inappropriate heterochromatin assembly can lead to inappropriate silencing and other deleterious effects. Hence targeting heterochromatin assembly to appropriate regions of the genome is of utmost importance. Here we focus on heterochromatin assembly in Drosophila melanogaster, the model organism in which variegation, or cell-to-cell variable gene expression resulting from heterochromatin formation, was first described. In particular, we review the potential role of transposable elements as genetic determinants of the chromatin state and examine how small RNA pathways may participate in the process of targeted heterochromatin formation.
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Affiliation(s)
- M Sentmanat
- Department of Biology, Washington University, St. Louis, MO 63130-4899, USA
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42
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Eissenberg JC, Elgin SCR. HP1a: a structural chromosomal protein regulating transcription. Trends Genet 2014; 30:103-10. [PMID: 24555990 DOI: 10.1016/j.tig.2014.01.002] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 01/17/2014] [Accepted: 01/17/2014] [Indexed: 01/16/2023]
Abstract
Heterochromatin protein 1 (HP1a in Drosophila) is a conserved eukaryotic chromosomal protein that is prominently associated with pericentric heterochromatin and mediates the concomitant gene silencing. Mechanistic studies implicate HP1 family proteins as 'hub proteins,' able to interact with a variety of chromosomal proteins through the chromo-shadow domain (CSD), as well as to recognize key histone modification sites [primarily histone H3 di/trimethyl Lys9 (H3K9me2/3)] through the chromodomain (CD). Consequently, HP1 has many important roles in chromatin architecture and impacts both gene expression and gene silencing, utilizing a variety of mechanisms. Clearly, HP1 function is altered by context, and potentially by post-translational modifications (PTMs). Here, we report on recent ideas as to how this versatile protein accomplishes its diverse functions.
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Affiliation(s)
- Joel C Eissenberg
- Edward A. Doisy Department of Biochemistry & Molecular Biology, Saint Louis University School of Medicine, Doisy Research Center, 1100 South Grand Boulevard, St Louis, MO 63104, USA
| | - Sarah C R Elgin
- Department of Biology, Washington University in St. Louis, Campus Box 1037, One Brookings Drive, St Louis, MO 63130-4899, USA.
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Clough E, Tedeschi T, Hazelrigg T. Epigenetic regulation of oogenesis and germ stem cell maintenance by the Drosophila histone methyltransferase Eggless/dSetDB1. Dev Biol 2014; 388:181-91. [PMID: 24485852 DOI: 10.1016/j.ydbio.2014.01.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Revised: 01/10/2014] [Accepted: 01/17/2014] [Indexed: 11/16/2022]
Abstract
The Drosophila melanogaster histone lysine methyltransferase (HKMT) Eggless (Egg/dSETDB1) catalyzes methylation of Histone H3 lysine 9 (H3K9), a signature of repressive heterochromatin. Our previous studies showed that H3K9 methylation by Egg is required for oogenesis. Here we analyze a set of EMS-induced mutations in the egg gene, identify the molecular lesions of these mutations, and compare the effects on oogenesis of both strong loss-of-function and weak hypomorphic alleles. These studies show that H3K9 methylation by Egg is required for multiple stages of oogenesis. Mosaic expression experiments show that the egg gene is not required intrinsically in the germ cells for their early differentiation, but is required in the germ cells for their survival past stage 5 of oogenesis. egg is also required in germ stem cells for their maintenance, since egg- germ stem cells initially survive but are not maintained as females age. Mosaic analysis also reveals that the early egg chamber budding defects in egg- ovaries are due to an intrinsic requirement for egg in follicle stem cells and their descendents, and that egg plays a non-autonomous role in somatic cells in the germarium to influence the differentiation of early germ cells.
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Affiliation(s)
- Emily Clough
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Thomas Tedeschi
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Tulle Hazelrigg
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
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Wang SH, Nan R, Accardo MC, Sentmanat M, Dimitri P, Elgin SCR. A distinct type of heterochromatin at the telomeric region of the Drosophila melanogaster Y chromosome. PLoS One 2014; 9:e86451. [PMID: 24475122 PMCID: PMC3901700 DOI: 10.1371/journal.pone.0086451] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 12/16/2013] [Indexed: 11/24/2022] Open
Abstract
Heterochromatin assembly and its associated phenotype, position effect variegation (PEV), provide an informative system to study chromatin structure and genome packaging. In the fruit fly Drosophila melanogaster, the Y chromosome is entirely heterochromatic in all cell types except the male germline; as such, Y chromosome dosage is a potent modifier of PEV. However, neither Y heterochromatin composition, nor its assembly, has been carefully studied. Here, we report the mapping and characterization of eight reporter lines that show male-specific PEV. In all eight cases, the reporter insertion sites lie in the telomeric transposon array (HeT-A and TART-B2 homologous repeats) of the Y chromosome short arm (Ys). Investigations of the impact on the PEV phenotype of mutations in known heterochromatin proteins (i.e., modifiers of PEV) show that this Ys telomeric region is a unique heterochromatin domain: it displays sensitivity to mutations in HP1a, EGG and SU(VAR)3-9, but no sensitivity to Su(z)2 mutations. It appears that the endo-siRNA pathway plays a major targeting role for this domain. Interestingly, an ectopic copy of 1360 is sufficient to induce a piRNA targeting mechanism to further enhance silencing of a reporter cytologically localized to the Ys telomere. These results demonstrate the diversity of heterochromatin domains, and the corresponding variation in potential targeting mechanisms.
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Affiliation(s)
- Sidney H. Wang
- Department of Biology, Washington University, St. Louis, Missouri, United States of America
| | - Ruth Nan
- Department of Biology, Washington University, St. Louis, Missouri, United States of America
| | - Maria C. Accardo
- Dipartimento di Biologia e Biotecnologie “Charles Darwin” and Istituto Pasteur Fondazione Cenci-Bolognetti, Sapienza Università di Roma, Roma, Italy
| | - Monica Sentmanat
- Department of Biology, Washington University, St. Louis, Missouri, United States of America
| | - Patrizio Dimitri
- Dipartimento di Biologia e Biotecnologie “Charles Darwin” and Istituto Pasteur Fondazione Cenci-Bolognetti, Sapienza Università di Roma, Roma, Italy
| | - Sarah C. R. Elgin
- Department of Biology, Washington University, St. Louis, Missouri, United States of America
- * E-mail:
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Herz HM, Garruss A, Shilatifard A. SET for life: biochemical activities and biological functions of SET domain-containing proteins. Trends Biochem Sci 2013; 38:621-39. [PMID: 24148750 DOI: 10.1016/j.tibs.2013.09.004] [Citation(s) in RCA: 219] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Revised: 09/06/2013] [Accepted: 09/12/2013] [Indexed: 01/23/2023]
Affiliation(s)
- Hans-Martin Herz
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
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Gu T, Elgin SCR. Maternal depletion of Piwi, a component of the RNAi system, impacts heterochromatin formation in Drosophila. PLoS Genet 2013; 9:e1003780. [PMID: 24068954 PMCID: PMC3777992 DOI: 10.1371/journal.pgen.1003780] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 07/25/2013] [Indexed: 02/05/2023] Open
Abstract
A persistent question in epigenetics is how heterochromatin is targeted for assembly at specific domains, and how that chromatin state is faithfully transmitted. Stable heterochromatin is necessary to silence transposable elements (TEs) and maintain genome integrity. Both the RNAi system and heterochromatin components HP1 (Swi6) and H3K9me2/3 are required for initial establishment of heterochromatin structures in S. pombe. Here we utilize both loss of function alleles and the newly developed Drosophila melanogaster transgenic shRNA lines to deplete proteins of interest at specific development stages to dissect their roles in heterochromatin assembly in early zygotes and in maintenance of the silencing chromatin state during development. Using reporters subject to Position Effect Variegation (PEV), we find that depletion of key proteins in the early embryo can lead to loss of silencing assayed at adult stages. The piRNA component Piwi is required in the early embryo for reporter silencing in non-gonadal somatic cells, but knock-down during larval stages has no impact. This implies that Piwi is involved in targeting HP1a when heterochromatin is established at the late blastoderm stage and possibly also during embryogenesis, but that the silent chromatin state created is transmitted through cell division independent of the piRNA system. In contrast, heterochromatin structural protein HP1a is required for both initial heterochromatin assembly and the following mitotic inheritance. HP1a profiles in piwi mutant animals confirm that Piwi depletion leads to decreased HP1a levels in pericentric heterochromatin, particularly in TEs. The results suggest that the major role of the piRNA system in assembly of heterochromatin in non-gonadal somatic cells occurs in the early embryo during heterochromatin formation, and further demonstrate that failure of heterochromatin formation in the early embryo impacts the phenotype of the adult.
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Affiliation(s)
- Tingting Gu
- Department of Biology, Washington University, Saint Louis, Missouri, United States of America
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47
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Elgin SCR, Reuter G. Position-effect variegation, heterochromatin formation, and gene silencing in Drosophila. Cold Spring Harb Perspect Biol 2013; 5:a017780. [PMID: 23906716 DOI: 10.1101/cshperspect.a017780] [Citation(s) in RCA: 319] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Position-effect variegation (PEV) results when a gene normally in euchromatin is juxtaposed with heterochromatin by rearrangement or transposition. When heterochromatin packaging spreads across the heterochromatin/euchromatin border, it causes transcriptional silencing in a stochastic pattern. PEV is intensely studied in Drosophila using the white gene. Screens for dominant mutations that suppress or enhance white variegation have identified many conserved epigenetic factors, including the histone H3 lysine 9 methyltransferase SU(VAR)3-9. Heterochromatin protein HP1a binds H3K9me2/3 and interacts with SU(VAR)3-9, creating a core memory system. Genetic, molecular, and biochemical analysis of PEV in Drosophila has contributed many key findings concerning establishment and maintenance of heterochromatin with concomitant gene silencing.
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Affiliation(s)
- Sarah C R Elgin
- Department of Biology, Washington University, St. Louis, Missouri 63130, USA.
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48
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Lundberg LE, Stenberg P, Larsson J. HP1a, Su(var)3-9, SETDB1 and POF stimulate or repress gene expression depending on genomic position, gene length and expression pattern in Drosophila melanogaster. Nucleic Acids Res 2013; 41:4481-94. [PMID: 23476027 PMCID: PMC3632140 DOI: 10.1093/nar/gkt158] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Heterochromatin protein 1a (HP1a) is a chromatin-associated protein important for the formation and maintenance of heterochromatin. In Drosophila, the two histone methyltransferases SETDB1 and Su(var)3-9 mediate H3K9 methylation marks that initiates the establishment and spreading of HP1a-enriched chromatin. Although HP1a is generally regarded as a factor that represses gene transcription, several reports have linked HP1a binding to active genes, and in some cases, it has been shown to stimulate transcriptional activity. To clarify the function of HP1a in transcription regulation and its association with Su(var)3-9, SETDB1 and the chromosome 4-specific protein POF, we conducted genome-wide expression studies and combined the results with available binding data in Drosophila melanogaster. The results suggest that HP1a, SETDB1 and Su(var)3-9 repress genes on chromosome 4, where non-ubiquitously expressed genes are preferentially targeted, and stimulate genes in pericentromeric regions. Further, we showed that on chromosome 4, Su(var)3-9, SETDB1 and HP1a target the same genes. In addition, we found that transposons are repressed by HP1a and Su(var)3-9 and that the binding level and expression effects of HP1a are affected by gene length. Our results indicate that genes have adapted to be properly expressed in their local chromatin environment.
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Affiliation(s)
- Lina E Lundberg
- Department of Molecular Biology, Umeå University, SE-90187 Umeå, Sweden
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50
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Figueiredo MLA, Philip P, Stenberg P, Larsson J. HP1a recruitment to promoters is independent of H3K9 methylation in Drosophila melanogaster. PLoS Genet 2012; 8:e1003061. [PMID: 23166515 PMCID: PMC3499360 DOI: 10.1371/journal.pgen.1003061] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 09/19/2012] [Indexed: 11/19/2022] Open
Abstract
Heterochromatin protein 1 (HP1) proteins, recognized readers of the heterochromatin mark methylation of histone H3 lysine 9 (H3K9me), are important regulators of heterochromatin-mediated gene silencing and chromosome structure. In Drosophila melanogaster three histone lysine methyl transferases (HKMTs) are associated with the methylation of H3K9: Su(var)3-9, Setdb1, and G9a. To probe the dependence of HP1a binding on H3K9me, its dependence on these three HKMTs, and the division of labor between the HKMTs, we have examined correlations between HP1a binding and H3K9me patterns in wild type and null mutants of these HKMTs. We show here that Su(var)3-9 controls H3K9me-dependent binding of HP1a in pericentromeric regions, while Setdb1 controls it in cytological region 2L:31 and (together with POF) in chromosome 4. HP1a binds to the promoters and within bodies of active genes in these three regions. More importantly, however, HP1a binding at promoters of active genes is independent of H3K9me and POF. Rather, it is associated with heterochromatin protein 2 (HP2) and open chromatin. Our results support a hypothesis in which HP1a nucleates with high affinity independently of H3K9me in promoters of active genes and then spreads via H3K9 methylation and transient looping contacts with those H3K9me target sites. HP1 is a key protein in heterochromatin and epigenetic silencing, a phenomenon involving chromatin condensation. It is generally accepted that HP1 forms a dimer that links two adjacent nucleosomes through interactions with histone 3 methylated at lysine 9 (H3K9me). Since HP1 also interacts with the histone lysine methyltransferases (HKMTs) generating this modification, histone H3 becomes methylated and HP1 spreading is propagated. Here, we show that HP1a in Drosophila binds to promoters of active genes on chromosome 4 and pericentromeric regions. In contrast to current dogma, this binding is independent of H3K9me. In the presence of the HKMTs and H3K9me, HP1a is also enriched within the bodies of the bound genes. These findings shed new light on the role of HP1a and the epigenetic nature of this chromatin mark. We propose that HP1a interacts independently of H3K9me with the nucleosome with high affinity, probably via the H3 histone-fold. This interaction is followed by a more transient interaction between HP1a and H3K9me, which results in spreading of the HP1a enrichment into gene bodies. Overall, the presented results and hypothesized model provide an explanation for this epigenetic mark and possibly more general insights into the relationships between chromo-domain proteins and methylated histones.
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Affiliation(s)
| | - Philge Philip
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Computational Life Science Cluster (CLiC), Umeå University, Umeå, Sweden
| | - Per Stenberg
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Computational Life Science Cluster (CLiC), Umeå University, Umeå, Sweden
| | - Jan Larsson
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- * E-mail:
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