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Xiang G, He X, Giardine BM, Isaac KJ, Taylor DJ, McCoy RC, Jansen C, Keller CA, Wixom AQ, Cockburn A, Miller A, Qi Q, He Y, Li Y, Lichtenberg J, Heuston EF, Anderson SM, Luan J, Vermunt MW, Yue F, Sauria MEG, Schatz MC, Taylor J, Gottgens B, Hughes JR, Higgs DR, Weiss MJ, Cheng Y, Blobel GA, Bodine DM, Zhang Y, Li Q, Mahony S, Hardison RC. Interspecies regulatory landscapes and elements revealed by novel joint systematic integration of human and mouse blood cell epigenomes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.04.02.535219. [PMID: 37066352 PMCID: PMC10103973 DOI: 10.1101/2023.04.02.535219] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Knowledge of locations and activities of cis-regulatory elements (CREs) is needed to decipher basic mechanisms of gene regulation and to understand the impact of genetic variants on complex traits. Previous studies identified candidate CREs (cCREs) using epigenetic features in one species, making comparisons difficult between species. In contrast, we conducted an interspecies study defining epigenetic states and identifying cCREs in blood cell types to generate regulatory maps that are comparable between species, using integrative modeling of eight epigenetic features jointly in human and mouse in our Validated Systematic Integration (VISION) Project. The resulting catalogs of cCREs are useful resources for further studies of gene regulation in blood cells, indicated by high overlap with known functional elements and strong enrichment for human genetic variants associated with blood cell phenotypes. The contribution of each epigenetic state in cCREs to gene regulation, inferred from a multivariate regression, was used to estimate epigenetic state Regulatory Potential (esRP) scores for each cCRE in each cell type, which were used to categorize dynamic changes in cCREs. Groups of cCREs displaying similar patterns of regulatory activity in human and mouse cell types, obtained by joint clustering on esRP scores, harbored distinctive transcription factor binding motifs that were similar between species. An interspecies comparison of cCREs revealed both conserved and species-specific patterns of epigenetic evolution. Finally, we showed that comparisons of the epigenetic landscape between species can reveal elements with similar roles in regulation, even in the absence of genomic sequence alignment.
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2
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Shi TH, Sugishita H, Gotoh Y. Crosstalk within and beyond the Polycomb repressive system. J Cell Biol 2024; 223:e202311021. [PMID: 38506728 PMCID: PMC10955045 DOI: 10.1083/jcb.202311021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 03/21/2024] Open
Abstract
The development of multicellular organisms depends on spatiotemporally controlled differentiation of numerous cell types and their maintenance. To generate such diversity based on the invariant genetic information stored in DNA, epigenetic mechanisms, which are heritable changes in gene function that do not involve alterations to the underlying DNA sequence, are required to establish and maintain unique gene expression programs. Polycomb repressive complexes represent a paradigm of epigenetic regulation of developmentally regulated genes, and the roles of these complexes as well as the epigenetic marks they deposit, namely H3K27me3 and H2AK119ub, have been extensively studied. However, an emerging theme from recent studies is that not only the autonomous functions of the Polycomb repressive system, but also crosstalks of Polycomb with other epigenetic modifications, are important for gene regulation. In this review, we summarize how these crosstalk mechanisms have improved our understanding of Polycomb biology and how such knowledge could help with the design of cancer treatments that target the dysregulated epigenome.
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Affiliation(s)
- Tianyi Hideyuki Shi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Hiroki Sugishita
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
- International Research Center for Neurointelligence, The University of Tokyo, Tokyo, Japan
| | - Yukiko Gotoh
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
- International Research Center for Neurointelligence, The University of Tokyo, Tokyo, Japan
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3
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Brown JL, Zhang L, Rocha PP, Kassis JA, Sun MA. Polycomb protein binding and looping in the ON transcriptional state. SCIENCE ADVANCES 2024; 10:eadn1837. [PMID: 38657072 PMCID: PMC11042752 DOI: 10.1126/sciadv.adn1837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 03/22/2024] [Indexed: 04/26/2024]
Abstract
Polycomb group (PcG) proteins mediate epigenetic silencing of important developmental genes by modifying histones and compacting chromatin through two major protein complexes, PRC1 and PRC2. These complexes are recruited to DNA by CpG islands (CGIs) in mammals and Polycomb response elements (PREs) in Drosophila. When PcG target genes are turned OFF, PcG proteins bind to PREs or CGIs, and PREs serve as anchors that loop together and stabilize gene silencing. Here, we address which PcG proteins bind to PREs and whether PREs mediate looping when their targets are in the ON transcriptional state. While the binding of most PcG proteins decreases at PREs in the ON state, one PRC1 component, Ph, remains bound. Further, PREs can loop to each other and with presumptive enhancers in the ON state and, like CGIs, may act as tethering elements between promoters and enhancers. Overall, our data suggest that PREs are important looping elements for developmental loci in both the ON and OFF states.
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Affiliation(s)
- J. Lesley Brown
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Liangliang Zhang
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Pedro P. Rocha
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
- National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Judith A. Kassis
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ming-an Sun
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonosis, Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, China
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4
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Lundkvist MJ, Lizana L, Schwartz YB. Forecasting histone methylation by Polycomb complexes with minute-scale precision. SCIENCE ADVANCES 2023; 9:eadj8198. [PMID: 38134278 PMCID: PMC10745708 DOI: 10.1126/sciadv.adj8198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 11/22/2023] [Indexed: 12/24/2023]
Abstract
Animals use the Polycomb system to epigenetically repress developmental genes. The repression requires trimethylation of lysine 27 of histone H3 (H3K27me3) by Polycomb Repressive Complex 2 (PRC2), but the dynamics of this process is poorly understood. To bridge the gap, we developed a computational model that forecasts H3K27 methylation in Drosophila with high temporal resolution and spatial accuracy of contemporary experimental techniques. Using this model, we show that pools of methylated H3K27 in dividing cells are defined by the effective concentration of PRC2 and the replication frequency. We find that the allosteric stimulation by preexisting H3K27me3 makes PRC2 better in methylating developmental genes as opposed to indiscriminate methylation throughout the genome. Applied to Drosophila development, our model argues that, in this organism, the intergenerationally inherited H3K27me3 does not "survive" rapid cycles of embryonic chromatin replication and is unlikely to transmit the memory of epigenetic repression to the offspring. Our model is adaptable to other organisms, including mice and humans.
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Affiliation(s)
| | - Ludvig Lizana
- Integrated Science Lab, Department of Physics, Umeå University, Umeå, Sweden
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5
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Barrasa JI, Kahn TG, Lundkvist MJ, Schwartz YB. DNA elements tether canonical Polycomb Repressive Complex 1 to human genes. Nucleic Acids Res 2023; 51:11613-11633. [PMID: 37855680 PMCID: PMC10681801 DOI: 10.1093/nar/gkad889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 09/25/2023] [Accepted: 10/11/2023] [Indexed: 10/20/2023] Open
Abstract
Development of multicellular animals requires epigenetic repression by Polycomb group proteins. The latter assemble in multi-subunit complexes, of which two kinds, Polycomb Repressive Complex 1 (PRC1) and Polycomb Repressive Complex 2 (PRC2), act together to repress key developmental genes. How PRC1 and PRC2 recognize specific genes remains an open question. Here we report the identification of several hundreds of DNA elements that tether canonical PRC1 to human developmental genes. We use the term tether to describe a process leading to a prominent presence of canonical PRC1 at certain genomic sites, although the complex is unlikely to interact with DNA directly. Detailed analysis indicates that sequence features associated with PRC1 tethering differ from those that favour PRC2 binding. Throughout the genome, the two kinds of sequence features mix in different proportions to yield a gamut of DNA elements that range from those tethering predominantly PRC1 or PRC2 to ones capable of tethering both complexes. The emerging picture is similar to the paradigmatic targeting of Polycomb complexes by Polycomb Response Elements (PREs) of Drosophila but providing for greater plasticity.
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Affiliation(s)
- Juan I Barrasa
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden
| | - Tatyana G Kahn
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden
| | - Moa J Lundkvist
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden
| | - Yuri B Schwartz
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden
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6
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Godneeva B, Fejes Tóth K, Quan B, Chou TF, Aravin AA. Impact of Germline Depletion of Bonus on Chromatin State in Drosophila Ovaries. Cells 2023; 12:2629. [PMID: 37998364 PMCID: PMC10670193 DOI: 10.3390/cells12222629] [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: 10/18/2023] [Revised: 11/07/2023] [Accepted: 11/13/2023] [Indexed: 11/25/2023] Open
Abstract
Gene expression is controlled via complex regulatory mechanisms involving transcription factors, chromatin modifications, and chromatin regulatory factors. Histone modifications, such as H3K27me3, H3K9ac, and H3K27ac, play an important role in controlling chromatin accessibility and transcriptional output. In vertebrates, the Transcriptional Intermediary Factor 1 (TIF1) family of proteins play essential roles in transcription, cell differentiation, DNA repair, and mitosis. Our study focused on Bonus, the sole member of the TIF1 family in Drosophila, to investigate its role in organizing epigenetic modifications. Our findings demonstrated that depleting Bonus in ovaries leads to a mild reduction in the H3K27me3 level over transposon regions and alters the distribution of active H3K9ac marks on specific protein-coding genes. Additionally, through mass spectrometry analysis, we identified novel interacting partners of Bonus in ovaries, such as PolQ, providing a comprehensive understanding of the associated molecular pathways. Furthermore, our research revealed Bonus's interactions with the Polycomb Repressive Complex 2 and its co-purification with select histone acetyltransferases, shedding light on the underlying mechanisms behind these changes in chromatin modifications.
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Affiliation(s)
- Baira Godneeva
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Katalin Fejes Tóth
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Baiyi Quan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Proteome Exploration Laboratory, Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Tsui-Fen Chou
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Proteome Exploration Laboratory, Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Alexei A. Aravin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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Cheng Y, Chan F, Kassis JA. The activity of engrailed imaginal disc enhancers is modulated epigenetically by chromatin and autoregulation. PLoS Genet 2023; 19:e1010826. [PMID: 37967127 PMCID: PMC10686433 DOI: 10.1371/journal.pgen.1010826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 11/29/2023] [Accepted: 10/31/2023] [Indexed: 11/17/2023] Open
Abstract
engrailed (en) encodes a homeodomain transcription factor crucial for the proper development of Drosophila embryos and adults. Like many developmental transcription factors, en expression is regulated by many enhancers, some of overlapping function, that drive expression in spatially and temporally restricted patterns. The en embryonic enhancers are located in discrete DNA fragments that can function correctly in small reporter transgenes. In contrast, the en imaginal disc enhancers (IDEs) do not function correctly in small reporter transgenes. En is expressed in the posterior compartment of wing imaginal discs; in contrast, small IDE-reporter transgenes are expressed mainly in the anterior compartment. We found that En binds to the IDEs and suggest that it may directly repress IDE function and modulate En expression levels. We identified two en IDEs, O and S. Deletion of either of these IDEs from a 79kb HA-en rescue transgene (HAen79) caused a loss-of-function en phenotype when the HAen79 transgene was the sole source of En. In contrast, flies with a deletion of the same IDEs from an endogenous en gene had no phenotype, suggesting a resiliency not seen in the HAen79 rescue transgene. Inserting a gypsy insulator in HAen79 between en regulatory DNA and flanking sequences strengthened the activity of HAen79, giving better function in both the ON and OFF transcriptional states. Altogether our data suggest that the en IDEs stimulate expression in the entire imaginal disc, and that the ON/OFF state is set by epigenetic memory set by the embryonic enhancers. This epigenetic regulation is similar to that of the Ultrabithorax IDEs and we suggest that the activity of late-acting enhancers in other genes may be similarly regulated.
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Affiliation(s)
- Yuzhong Cheng
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Fountane Chan
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Judith A. Kassis
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
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8
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Brown HE, Weasner BP, Weasner BM, Kumar JP. Polycomb safeguards imaginal disc specification through control of the Vestigial-Scalloped complex. Development 2023; 150:dev201872. [PMID: 37702007 PMCID: PMC10560572 DOI: 10.1242/dev.201872] [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: 04/18/2023] [Accepted: 09/04/2023] [Indexed: 09/14/2023]
Abstract
A fundamental goal of developmental biology is to understand how cell and tissue fates are specified. The imaginal discs of Drosophila are excellent model systems for addressing this paradigm as their fate can be redirected when discs regenerate after injury or when key selector genes are misregulated. Here, we show that when Polycomb expression is reduced, the wing selector gene vestigial is ectopically activated. This leads to the inappropriate formation of the Vestigial-Scalloped complex, which forces the eye to transform into a wing. We further demonstrate that disrupting this complex does not simply block wing formation or restore eye development. Instead, immunohistochemistry and high-throughput genomic analysis show that the eye-antennal disc unexpectedly undergoes hyperplastic growth with multiple domains being organized into other imaginal discs and tissues. These findings provide insight into the complex developmental landscape that tissues must navigate before adopting their final fate.
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Affiliation(s)
- Haley E. Brown
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | | | - Bonnie M. Weasner
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Justin P. Kumar
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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9
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Son W, Chung KW. Targeted recombination of homologous chromosomes using CRISPR-Cas9. FEBS Open Bio 2023; 13:1658-1666. [PMID: 37462508 PMCID: PMC10476559 DOI: 10.1002/2211-5463.13676] [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: 03/07/2023] [Revised: 06/22/2023] [Accepted: 07/17/2023] [Indexed: 07/28/2023] Open
Abstract
CRISPR mutagenesis is an efficient way to disrupt specific target genes in many model organisms. We previously devised a targeted CRISPR recombination method to generate intragenic recombinants of alleles in Drosophila. Here, we assessed the applicability of CRISPR targeting-induced recombination to different genetic loci. We compared the ectopic recombination rates in the male germline by CRISPR targeting at two neighboring genetic loci within the genomic region that consists of the repressed chromatin domain of the Lobe gene, and the transcriptionally active domain of PRAS40. Targeting around the transcription initiation of PRAS40 resulted in higher recombination rates of homologous chromosomes than targeting at the Lobe intron. Based on the efficient homologous recombination by CRISPR targeting observed around transcriptionally active loci, we further investigated targeted recombination between P-elements that are inserted at different genomic locations. Male recombination by CRISPR targeting of P-elements located proximally and distally to the ebony gene produced recombinants deficient for the intervening region of ebony transcription. Taken together, we suggest that targeted homologous recombination by CRISPR targeting may have specific genetic applications, such as generation of allelic combinations or chromosomal variations.
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Affiliation(s)
- Wonseok Son
- Department of Biological Sciences and BK21 Team for Field‐oriented BioCore Human Resources DevelopmentKongju National UniversityGongjuSouth Korea
| | - Ki Wha Chung
- Department of Biological Sciences and BK21 Team for Field‐oriented BioCore Human Resources DevelopmentKongju National UniversityGongjuSouth Korea
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10
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Lizana L, Nahali N, Schwartz YB. Polycomb proteins translate histone methylation to chromatin folding. J Biol Chem 2023; 299:105080. [PMID: 37499944 PMCID: PMC10470199 DOI: 10.1016/j.jbc.2023.105080] [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: 12/13/2022] [Revised: 07/18/2023] [Accepted: 07/21/2023] [Indexed: 07/29/2023] Open
Abstract
Epigenetic repression often involves covalent histone modifications. Yet, how the presence of a histone mark translates into changes in chromatin structure that ultimately benefits the repression is largely unclear. Polycomb group proteins comprise a family of evolutionarily conserved epigenetic repressors. They act as multi-subunit complexes one of which tri-methylates histone H3 at Lysine 27 (H3K27). Here we describe a novel Monte Carlo-Molecular Dynamics simulation framework, which we employed to discover that stochastic interaction of Polycomb Repressive Complex 1 (PRC1) with tri-methylated H3K27 is sufficient to fold the methylated chromatin. Unexpectedly, such chromatin folding leads to spatial clustering of the DNA elements bound by PRC1. Our results provide further insight into mechanisms of epigenetic repression and the process of chromatin folding in response to histone methylation.
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Affiliation(s)
- Ludvig Lizana
- Department of Physics, Integrated Science Lab, Umeå University, Umeå, Sweden.
| | - Negar Nahali
- Department of Physics, Integrated Science Lab, Umeå University, Umeå, Sweden; Department of Informatics, Centre for Bioinformatics, University of Oslo, Oslo, Norway
| | - Yuri B Schwartz
- Department of Molecular Biology, Umeå University, Umeå, Sweden.
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11
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Erokhin M, Mogila V, Lomaev D, Chetverina D. Polycomb Recruiters Inside and Outside of the Repressed Domains. Int J Mol Sci 2023; 24:11394. [PMID: 37511153 PMCID: PMC10379775 DOI: 10.3390/ijms241411394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/24/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
The establishment and stable inheritance of individual patterns of gene expression in different cell types are required for the development of multicellular organisms. The important epigenetic regulators are the Polycomb group (PcG) and Trithorax group (TrxG) proteins, which control the silenced and active states of genes, respectively. In Drosophila, the PcG/TrxG group proteins are recruited to the DNA regulatory sequences termed the Polycomb response elements (PREs). The PREs are composed of the binding sites for different DNA-binding proteins, the so-called PcG recruiters. Currently, the role of the PcG recruiters in the targeting of the PcG proteins to PREs is well documented. However, there are examples where the PcG recruiters are also implicated in the active transcription and in the TrxG function. In addition, there is increasing evidence that the genome-wide PcG recruiters interact with the chromatin outside of the PREs and overlap with the proteins of differing regulatory classes. Recent studies of the interactomes of the PcG recruiters significantly expanded our understanding that they have numerous interactors besides the PcG proteins and that their functions extend beyond the regulation of the PRE repressive activity. Here, we summarize current data about the functions of the PcG recruiters.
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Affiliation(s)
- Maksim Erokhin
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Vladic Mogila
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Dmitry Lomaev
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Darya Chetverina
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
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12
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Erokhin M, Brown JL, Lomaev D, Vorobyeva NE, Zhang L, Fab L, Mazina M, Kulakovskiy I, Ziganshin R, Schedl P, Georgiev P, Sun MA, Kassis J, Chetverina D. Crol contributes to PRE-mediated repression and Polycomb group proteins recruitment in Drosophila. Nucleic Acids Res 2023; 51:6087-6100. [PMID: 37140047 PMCID: PMC10325914 DOI: 10.1093/nar/gkad336] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 04/20/2023] [Indexed: 05/05/2023] Open
Abstract
The Polycomb group (PcG) proteins are fundamental epigenetic regulators that control the repressive state of target genes in multicellular organisms. One of the open questions is defining the mechanisms of PcG recruitment to chromatin. In Drosophila, the crucial role in PcG recruitment is thought to belong to DNA-binding proteins associated with Polycomb response elements (PREs). However, current data suggests that not all PRE-binding factors have been identified. Here, we report the identification of the transcription factor Crooked legs (Crol) as a novel PcG recruiter. Crol is a C2H2-type Zinc Finger protein that directly binds to poly(G)-rich DNA sequences. Mutation of Crol binding sites as well as crol CRISPR/Cas9 knockout diminish the repressive activity of PREs in transgenes. Like other PRE-DNA binding proteins, Crol co-localizes with PcG proteins inside and outside of H3K27me3 domains. Crol knockout impairs the recruitment of the PRC1 subunit Polyhomeotic and the PRE-binding protein Combgap at a subset of sites. The decreased binding of PcG proteins is accompanied by dysregulated transcription of target genes. Overall, our study identified Crol as a new important player in PcG recruitment and epigenetic regulation.
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Affiliation(s)
- Maksim Erokhin
- Group of Chromatin Biology, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - J Lesley Brown
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Dmitry Lomaev
- Group of Epigenetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Nadezhda E Vorobyeva
- Group of transcriptional complexes dynamics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Liangliang Zhang
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Lika V Fab
- Group of Chromatin Biology, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Marina Yu Mazina
- Group of hormone-dependent transcription regulation, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Ivan V Kulakovskiy
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow119991, Russia
| | - Rustam H Ziganshin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - Paul Schedl
- Department of Molecular Biology Princeton University, Princeton, NJ 08544, USA
| | - Pavel Georgiev
- Department of Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Ming-an Sun
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Judith A Kassis
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Darya Chetverina
- Group of Epigenetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
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13
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Cheng Y, Chan F, Kassis JA. The activity of engrailed imaginal disc enhancers is modulated epigenetically by chromatin and autoregulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.15.545191. [PMID: 37502849 PMCID: PMC10370174 DOI: 10.1101/2023.06.15.545191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
engrailed (en) encodes a homeodomain transcription factor crucial for the proper development of Drosophila embryos and adults. Like many developmental transcription factors, en expression is regulated by many enhancers, some of overlapping function, that drive expression in spatially and temporally restricted patterns. The en embryonic enhancers are located in discrete DNA fragments that can function correctly in small reporter transgenes. In contrast, the en imaginal disc enhancers (IDEs) do not function correctly in small reporter transgenes. En is expressed in the posterior compartment of wing imaginal disks; small IDE-reporter transgenes are expressed in the anterior compartment, the opposite of what is expected. Our data show that the En protein binds to en IDEs, and we suggest that En directly represses IDE function. We identified two en IDEs, 'O' and 'S'. Deletion of either of these IDEs from a 79kb HA-en rescue transgene (HAen79) caused a loss-of-function en phenotype when the HAen79 transgene was the sole source of En. In contrast, flies with a deletion of the same IDEs from the endogenous en gene had no phenotype, suggesting a resiliency not seen in the HAen79 rescue transgene. Inserting a gypsy insulator in HAen79 between en regulatory DNA and flanking sequences strengthened the activity of HAen79, giving better function in both the ON and OFF transcriptional states. Altogether our data show that the en IDEs stimulate expression in the entire imaginal disc, and that the ON/OFF state is set by epigenetic regulators. Further, the endogenous locus imparts a stability to en function not seen even in a large transgene, reflecting the importance of both positive and negative epigenetic influences that act over relatively large distances in chromatin.
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Affiliation(s)
- Yuzhong Cheng
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Fountane Chan
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Judith A Kassis
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
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14
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Brown HE, Weasner BP, Weasner BM, Kumar JP. Polycomb safeguards imaginal disc specification through control of the Vestigial-Scalloped complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.11.536444. [PMID: 37090526 PMCID: PMC10120697 DOI: 10.1101/2023.04.11.536444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
A fundamental goal of developmental biology is to understand how cell and tissue fates are specified. The imaginal discs of Drosophila are excellent model systems for addressing this paradigm as their fate can be redirected when discs regenerate after injury or when key selector genes are mis-regulated. Here, we show that when Polycomb expression is reduced, the wing selector gene vestigial is ectopically activated. This leads to the inappropriate formation of the Vestigial-Scalloped complex which forces the eye to transform into a wing. We further demonstrate that disrupting this complex does not simply block wing formation or restore eye development. Instead, immunohistochemistry and high throughput genomic analysis show that the eye-antennal disc unexpectedly undergoes hyperplastic growth with multiple domains being organized into other imaginal discs and tissues. These findings provide insight into the complex developmental landscape that tissues must navigate before adopting their final fate. Summary Statement Here we describe a novel mechanism by which Pc promotes an eye fate during normal development and how the eye is reprogrammed into a wing in its absence.
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Affiliation(s)
- Haley E. Brown
- Department of Biology, Indiana University, Bloomington, IN 47405 USA
| | | | - Bonnie M. Weasner
- Department of Biology, Indiana University, Bloomington, IN 47405 USA
| | - Justin P. Kumar
- Department of Biology, Indiana University, Bloomington, IN 47405 USA
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15
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Glancy E, Wang C, Tuck E, Healy E, Amato S, Neikes HK, Mariani A, Mucha M, Vermeulen M, Pasini D, Bracken AP. PRC2.1- and PRC2.2-specific accessory proteins drive recruitment of different forms of canonical PRC1. Mol Cell 2023; 83:1393-1411.e7. [PMID: 37030288 PMCID: PMC10168607 DOI: 10.1016/j.molcel.2023.03.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 01/19/2023] [Accepted: 03/16/2023] [Indexed: 04/10/2023]
Abstract
Polycomb repressive complex 2 (PRC2) mediates H3K27me3 deposition, which is thought to recruit canonical PRC1 (cPRC1) via chromodomain-containing CBX proteins to promote stable repression of developmental genes. PRC2 forms two major subcomplexes, PRC2.1 and PRC2.2, but their specific roles remain unclear. Through genetic knockout (KO) and replacement of PRC2 subcomplex-specific subunits in naïve and primed pluripotent cells, we uncover distinct roles for PRC2.1 and PRC2.2 in mediating the recruitment of different forms of cPRC1. PRC2.1 catalyzes the majority of H3K27me3 at Polycomb target genes and is sufficient to promote recruitment of CBX2/4-cPRC1 but not CBX7-cPRC1. Conversely, while PRC2.2 is poor at catalyzing H3K27me3, we find that its accessory protein JARID2 is essential for recruitment of CBX7-cPRC1 and the consequent 3D chromatin interactions at Polycomb target genes. We therefore define distinct contributions of PRC2.1- and PRC2.2-specific accessory proteins to Polycomb-mediated repression and uncover a new mechanism for cPRC1 recruitment.
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Affiliation(s)
- Eleanor Glancy
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Cheng Wang
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Ellen Tuck
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Evan Healy
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Simona Amato
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139 Milan, Italy
| | - Hannah K Neikes
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Oncode Institute, Radboud University Nijmegen, 6525 GA Nijmegen, the Netherlands
| | - Andrea Mariani
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139 Milan, Italy
| | - Marlena Mucha
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Michiel Vermeulen
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Oncode Institute, Radboud University Nijmegen, 6525 GA Nijmegen, the Netherlands; The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Diego Pasini
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Via Adamello 16, 20139 Milan, Italy; Department of Health Sciences, University of Milan, Via A. di Rudini 8, 20142 Milan, Italy
| | - Adrian P Bracken
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland.
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16
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The Drosophila Fab-7 boundary modulates Abd-B gene activity by guiding an inversion of collinear chromatin organization and alternate promoter use. Cell Rep 2023; 42:111967. [PMID: 36640345 DOI: 10.1016/j.celrep.2022.111967] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 10/09/2022] [Accepted: 12/20/2022] [Indexed: 01/06/2023] Open
Abstract
Hox genes encode transcription factors that specify segmental identities along the anteroposterior body axis. These genes are organized in clusters, where their order corresponds to their activity along the body axis, a feature known as collinearity. In Drosophila, the BX-C cluster contains the three most posterior Hox genes, where their collinear activation incorporates progressive changes in histone modifications, chromatin architecture, and use of boundary elements and cis-regulatory regions. To dissect functional hierarchies, we compare chromatin organization in cell lines and larvae, with a focus on the Abd-B gene. Our work establishes the importance of the Fab-7 boundary for insulation between 3D domains carrying different histone modifications. Interestingly, we detect a non-canonical inversion of collinear chromatin dynamics at Abd-B, with the domain of active histone modifications progressively decreasing in size. This dynamic chromatin organization differentially activates the alternative promoters of the Abd-B gene, thereby expanding the possibilities for fine-tuning of transcriptional output.
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17
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Hanot M, Raby L, Völkel P, Le Bourhis X, Angrand PO. The Contribution of the Zebrafish Model to the Understanding of Polycomb Repression in Vertebrates. Int J Mol Sci 2023; 24:ijms24032322. [PMID: 36768643 PMCID: PMC9916924 DOI: 10.3390/ijms24032322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/20/2023] [Accepted: 01/21/2023] [Indexed: 01/26/2023] Open
Abstract
Polycomb group (PcG) proteins are highly conserved proteins assembled into two major types of complexes, PRC1 and PRC2, involved in the epigenetic silencing of a wide range of gene expression programs regulating cell fate and tissue development. The crucial role of PRC1 and PRC2 in the fundamental cellular processes and their involvement in human pathologies such as cancer attracted intense attention over the last few decades. Here, we review recent advancements regarding PRC1 and PRC2 function using the zebrafish model. We point out that the unique characteristics of the zebrafish model provide an exceptional opportunity to increase our knowledge of the role of the PRC1 and PRC2 complexes in tissue development, in the maintenance of organ integrity and in pathology.
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Affiliation(s)
- Mariette Hanot
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France
| | - Ludivine Raby
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France
| | - Pamela Völkel
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France
| | - Xuefen Le Bourhis
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France
| | - Pierre-Olivier Angrand
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277-CANTHER-Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France
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18
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Roles of Polycomb Complexes in the Reconstruction of 3D Genome Architecture during Preimplantation Embryonic Development. Genes (Basel) 2022; 13:genes13122382. [PMID: 36553649 PMCID: PMC9778514 DOI: 10.3390/genes13122382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 11/29/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
The appropriate deployment of developmental programs depends on complex genetic information encoded by genomic DNA sequences and their positioning and contacts in the three-dimensional (3D) space within the nucleus. Current studies using novel techniques including, but not limited to, Hi-C, ChIA-PET, and Hi-ChIP reveal that regulatory elements (Res), such as enhancers and promoters, may participate in the precise regulation of expression of tissue-specific genes important for both embryogenesis and organogenesis by recruiting Polycomb Group (PcG) complexes. PcG complexes usually poise the transcription of developmental genes by forming Polycomb bodies to compact poised enhancers and promoters marked by H3K27me3 in the 3D space. Additionally, recent studies have also uncovered their roles in transcriptional activation. To better understand the full complexities in the mechanisms of how PcG complexes regulate transcription and long-range 3D contacts of enhancers and promoters during developmental programs, we outline novel insights regarding PcG-associated dramatic changes in the 3D chromatin conformation in developmental programs of early embryos and naïve-ground-state transitions of pluripotent embryonic stem cells (ESCs), and highlight the distinct roles of unique and common subunits of canonical and non-canonical PcG complexes in shaping genome architectures and transcriptional programs.
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19
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Kim JJ, Kingston RE. Context-specific Polycomb mechanisms in development. Nat Rev Genet 2022; 23:680-695. [PMID: 35681061 PMCID: PMC9933872 DOI: 10.1038/s41576-022-00499-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2022] [Indexed: 12/11/2022]
Abstract
Polycomb group (PcG) proteins are crucial chromatin regulators that maintain repression of lineage-inappropriate genes and are therefore required for stable cell fate. Recent advances show that PcG proteins form distinct multi-protein complexes in various cellular environments, such as in early development, adult tissue maintenance and cancer. This surprising compositional diversity provides the basis for mechanistic diversity. Understanding this complexity deepens and refines the principles of PcG complex recruitment, target-gene repression and inheritance of memory. We review how the core molecular mechanism of Polycomb complexes operates in diverse developmental settings and propose that context-dependent changes in composition and mechanism are essential for proper epigenetic regulation in development.
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Affiliation(s)
- Jongmin J. Kim
- Department of Molecular Biology and MGH Research Institute, Massachusetts General Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Robert E. Kingston
- Department of Molecular Biology and MGH Research Institute, Massachusetts General Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA.,
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20
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Feijão T, Marques B, Silva RD, Carvalho C, Sobral D, Matos R, Tan T, Pereira A, Morais-de-Sá E, Maiato H, DeLuca SZ, Martinho RG. Polycomb group (PcG) proteins prevent the assembly of abnormal synaptonemal complex structures during meiosis. Proc Natl Acad Sci U S A 2022; 119:e2204701119. [PMID: 36215502 PMCID: PMC9586294 DOI: 10.1073/pnas.2204701119] [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: 03/16/2022] [Accepted: 07/18/2022] [Indexed: 11/18/2022] Open
Abstract
The synaptonemal complex (SC) is a proteinaceous scaffold that is assembled between paired homologous chromosomes during the onset of meiosis. Timely expression of SC coding genes is essential for SC assembly and successful meiosis. However, SC components have an intrinsic tendency to self-organize into abnormal repetitive structures, which are not assembled between the paired homologs and whose formation is potentially deleterious for meiosis and gametogenesis. This creates an interesting conundrum, where SC genes need to be robustly expressed during meiosis, but their expression must be carefully regulated to prevent the formation of anomalous SC structures. In this manuscript, we show that the Polycomb group protein Sfmbt, the Drosophila ortholog of human MBTD1 and L3MBTL2, is required to avoid excessive expression of SC genes during prophase I. Although SC assembly is normal after Sfmbt depletion, SC disassembly is abnormal with the formation of multiple synaptonemal complexes (polycomplexes) within the oocyte. Overexpression of the SC gene corona and depletion of other Polycomb group proteins are similarly associated with polycomplex formation during SC disassembly. These polycomplexes are highly dynamic and have a well-defined periodic structure. Further confirming the importance of Sfmbt, germ line depletion of this protein is associated with significant metaphase I defects and a reduction in female fertility. Since transcription of SC genes mostly occurs during early prophase I, our results suggest a role of Sfmbt and other Polycomb group proteins in downregulating the expression of these and other early prophase I genes during later stages of meiosis.
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Affiliation(s)
- Tália Feijão
- Algarve Biomedical Center Research Institute, Universidade do Algarve, 8005-139 Faro, Portugal
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, 4200-135 Portugal
- Department of Medical Sciences and Institute for Biomedicine, Universidade de Aveiro, 3810-193 Aveiro, Portugal
| | - Bruno Marques
- Algarve Biomedical Center Research Institute, Universidade do Algarve, 8005-139 Faro, Portugal
| | - Rui D. Silva
- Algarve Biomedical Center Research Institute, Universidade do Algarve, 8005-139 Faro, Portugal
- Faculty of Medicine and Biomedical Sciences, Universidade do Algarve, 8005-139 Faro, Portugal
| | - Célia Carvalho
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Daniel Sobral
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal
- Applied Molecular Biosciences Unit (UCIBIO), Department of Life Sciences, School of Science and Technology, NOVA University Lisbon, Caparica, 2819-516 Portugal
| | - Ricardo Matos
- Algarve Biomedical Center Research Institute, Universidade do Algarve, 8005-139 Faro, Portugal
| | - Tian Tan
- Department of Biology, Brandeis University, Waltham, MA 02453
| | - António Pereira
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, 4200-135 Portugal
| | - Eurico Morais-de-Sá
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, 4200-135 Portugal
| | - Hélder Maiato
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, 4200-135 Portugal
| | | | - Rui Gonçalo Martinho
- Algarve Biomedical Center Research Institute, Universidade do Algarve, 8005-139 Faro, Portugal
- Department of Medical Sciences and Institute for Biomedicine, Universidade de Aveiro, 3810-193 Aveiro, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
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21
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Bonnet J, Boichenko I, Kalb R, Le Jeune M, Maltseva S, Pieropan M, Finkl K, Fierz B, Müller J. PR-DUB preserves Polycomb repression by preventing excessive accumulation of H2Aub1, an antagonist of chromatin compaction. Genes Dev 2022; 36:1046-1061. [PMID: 36357125 PMCID: PMC9744231 DOI: 10.1101/gad.350014.122] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 10/18/2022] [Indexed: 11/12/2022]
Abstract
The Polycomb repressive complexes PRC1, PRC2, and PR-DUB repress target genes by modifying their chromatin. In Drosophila, PRC1 compacts chromatin and monoubiquitinates histone H2A at lysine 118 (H2Aub1), whereas PR-DUB is a major H2Aub1 deubiquitinase, but how H2Aub1 levels must be balanced for Polycomb repression remains unclear. We show that in early embryos, H2Aub1 is enriched at Polycomb target genes, where it facilitates H3K27me3 deposition by PRC2 to mark genes for repression. During subsequent stages of development, H2Aub1 becomes depleted from these genes and is no longer enriched when Polycomb maintains them repressed. Accordingly, Polycomb targets remain repressed in H2Aub1-deficient animals. In PR-DUB catalytic mutants, high levels of H2Aub1 accumulate at Polycomb target genes, and Polycomb repression breaks down. These high H2Aub1 levels do not diminish Polycomb protein complex binding or H3K27 trimethylation but increase DNA accessibility. We show that H2Aub1 interferes with nucleosome stacking and chromatin fiber folding in vitro. Consistent with this, Polycomb repression defects in PR-DUB mutants are exacerbated by reducing PRC1 chromatin compaction activity, but Polycomb repression is restored if PRC1 E3 ligase activity is removed. PR-DUB therefore acts as a rheostat that removes excessive H2Aub1 that, although deposited by PRC1, antagonizes PRC1-mediated chromatin compaction.
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Affiliation(s)
- Jacques Bonnet
- Laboratory of Chromatin Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Iulia Boichenko
- Laboratory of Biophysical Chemistry of Macromolecules, Institute of Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Reinhard Kalb
- Laboratory of Chromatin Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Mathilde Le Jeune
- Laboratory of Biophysical Chemistry of Macromolecules, Institute of Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Svetlana Maltseva
- Laboratory of Chromatin Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Mattia Pieropan
- Laboratory of Chromatin Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Katja Finkl
- Laboratory of Chromatin Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Beat Fierz
- Laboratory of Biophysical Chemistry of Macromolecules, Institute of Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Jürg Müller
- Laboratory of Chromatin Biology, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
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22
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Bondhus L, Wei A, Arboleda VA. DMRscaler: a scale-aware method to identify regions of differential DNA methylation spanning basepair to multi-megabase features. BMC Bioinformatics 2022; 23:364. [PMID: 36064314 PMCID: PMC9447346 DOI: 10.1186/s12859-022-04899-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 08/22/2022] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Pathogenic mutations in genes that control chromatin function have been implicated in rare genetic syndromes. These chromatin modifiers exhibit extraordinary diversity in the scale of the epigenetic changes they affect, from single basepair modifications by DNMT1 to whole genome structural changes by PRM1/2. Patterns of DNA methylation are related to a diverse set of epigenetic features across this full range of epigenetic scale, making DNA methylation valuable for mapping regions of general epigenetic dysregulation. However, existing methods are unable to accurately identify regions of differential methylation across this full range of epigenetic scale directly from DNA methylation data. RESULTS To address this, we developed DMRscaler, a novel method that uses an iterative windowing procedure to capture regions of differential DNA methylation (DMRs) ranging in size from single basepairs to whole chromosomes. We benchmarked DMRscaler against several DMR callers in simulated and natural data comparing XX and XY peripheral blood samples. DMRscaler was the only method that accurately called DMRs ranging in size from 100 bp to 1 Mb (pearson's r = 0.94) and up to 152 Mb on the X-chromosome. We then analyzed methylation data from rare-disease cohorts that harbor chromatin modifier gene mutations in NSD1, EZH2, and KAT6A where DMRscaler identified novel DMRs spanning gene clusters involved in development. CONCLUSION Taken together, our results show DMRscaler is uniquely able to capture the size of DMR features across the full range of epigenetic scale and identify novel, co-regulated regions that drive epigenetic dysregulation in human disease.
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Affiliation(s)
- Leroy Bondhus
- grid.19006.3e0000 0000 9632 6718Department of Human Genetics, David Geffen School of Medicine, UCLA, 615 Charles E. Young Drive South, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Computational Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095 USA
| | - Angela Wei
- grid.19006.3e0000 0000 9632 6718Department of Human Genetics, David Geffen School of Medicine, UCLA, 615 Charles E. Young Drive South, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Bioinformatics Interdepartmental PhD Program, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Computational Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095 USA
| | - Valerie A. Arboleda
- grid.19006.3e0000 0000 9632 6718Department of Human Genetics, David Geffen School of Medicine, UCLA, 615 Charles E. Young Drive South, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Bioinformatics Interdepartmental PhD Program, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Computational Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Molecular Biology Institute, UCLA, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, CA 90095 USA
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23
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Schüller A, Studt-Reinhold L, Strauss J. How to Completely Squeeze a Fungus-Advanced Genome Mining Tools for Novel Bioactive Substances. Pharmaceutics 2022; 14:1837. [PMID: 36145585 PMCID: PMC9505985 DOI: 10.3390/pharmaceutics14091837] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/23/2022] [Accepted: 08/29/2022] [Indexed: 11/17/2022] Open
Abstract
Fungal species have the capability of producing an overwhelming diversity of bioactive substances that can have beneficial but also detrimental effects on human health. These so-called secondary metabolites naturally serve as antimicrobial "weapon systems", signaling molecules or developmental effectors for fungi and hence are produced only under very specific environmental conditions or stages in their life cycle. However, as these complex conditions are difficult or even impossible to mimic in laboratory settings, only a small fraction of the true chemical diversity of fungi is known so far. This also implies that a large space for potentially new pharmaceuticals remains unexplored. We here present an overview on current developments in advanced methods that can be used to explore this chemical space. We focus on genetic and genomic methods, how to detect genes that harbor the blueprints for the production of these compounds (i.e., biosynthetic gene clusters, BGCs), and ways to activate these silent chromosomal regions. We provide an in-depth view of the chromatin-level regulation of BGCs and of the potential to use the CRISPR/Cas technology as an activation tool.
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Affiliation(s)
| | | | - Joseph Strauss
- Institute of Microbial Genetics, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences Vienna, A-3430 Tulln/Donau, Austria
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24
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De Novo Polycomb Recruitment and Repressive Domain Formation. EPIGENOMES 2022; 6:epigenomes6030025. [PMID: 35997371 PMCID: PMC9397058 DOI: 10.3390/epigenomes6030025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/15/2022] [Accepted: 08/18/2022] [Indexed: 11/29/2022] Open
Abstract
Every cell of an organism shares the same genome; even so, each cellular lineage owns a different transcriptome and proteome. The Polycomb group proteins (PcG) are essential regulators of gene repression patterning during development and homeostasis. However, it is unknown how the repressive complexes, PRC1 and PRC2, identify their targets and elicit new Polycomb domains during cell differentiation. Classical recruitment models consider the pre-existence of repressive histone marks; still, de novo target binding overcomes the absence of both H3K27me3 and H2AK119ub. The CpG islands (CGIs), non-core proteins, and RNA molecules are involved in Polycomb recruitment. Nonetheless, it is unclear how de novo targets are identified depending on the physiological context and developmental stage and which are the leading players stabilizing Polycomb complexes at domain nucleation sites. Here, we examine the features of de novo sites and the accessory elements bridging its recruitment and discuss the first steps of Polycomb domain formation and transcriptional regulation, comprehended by the experimental reconstruction of the repressive domains through time-resolved genomic analyses in mammals.
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25
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Voortman L, Anderson C, Urban E, Yuan L, Tran S, Neuhaus-Follini A, Derrick J, Gregor T, Johnston RJ. Temporally dynamic antagonism between transcription and chromatin compaction controls stochastic photoreceptor specification in flies. Dev Cell 2022; 57:1817-1832.e5. [PMID: 35835116 PMCID: PMC9378680 DOI: 10.1016/j.devcel.2022.06.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 05/09/2022] [Accepted: 06/20/2022] [Indexed: 01/12/2023]
Abstract
Stochastic mechanisms diversify cell fates during development. How cells randomly choose between two or more fates remains poorly understood. In the Drosophila eye, the random mosaic of two R7 photoreceptor subtypes is determined by expression of the transcription factor Spineless (Ss). We investigated how cis-regulatory elements and trans factors regulate nascent transcriptional activity and chromatin compaction at the ss gene locus during R7 development. The ss locus is in a compact state in undifferentiated cells. An early enhancer drives transcription in all R7 precursors, and the locus opens. In differentiating cells, transcription ceases and the ss locus stochastically remains open or compacts. In SsON R7s, ss is open and competent for activation by a late enhancer, whereas in SsOFF R7s, ss is compact, and repression prevents expression. Our results suggest that a temporally dynamic antagonism, in which transcription drives large-scale decompaction and then compaction represses transcription, controls stochastic fate specification.
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Affiliation(s)
- Lukas Voortman
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Caitlin Anderson
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Elizabeth Urban
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Luorongxin Yuan
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Sang Tran
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | | | - Josh Derrick
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Thomas Gregor
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA; Joseph Henry Laboratories of Physics, the Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Developmental and Stem Cell Biology, UMR3738, Institut Pasteur, 75015 Paris, France
| | - Robert J Johnston
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA.
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26
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Chetverina D, Vorobyeva NE, Mazina MY, Fab LV, Lomaev D, Golovnina A, Mogila V, Georgiev P, Ziganshin RH, Erokhin M. Comparative interactome analysis of the PRE DNA-binding factors: purification of the Combgap-, Zeste-, Psq-, and Adf1-associated proteins. Cell Mol Life Sci 2022; 79:353. [PMID: 35676368 PMCID: PMC11072172 DOI: 10.1007/s00018-022-04383-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 04/14/2022] [Accepted: 05/08/2022] [Indexed: 01/08/2023]
Abstract
The Polycomb group (PcG) and Trithorax group (TrxG) proteins are key epigenetic regulators controlling the silenced and active states of genes in multicellular organisms, respectively. In Drosophila, PcG/TrxG proteins are recruited to the chromatin via binding to specific DNA sequences termed polycomb response elements (PREs). While precise mechanisms of the PcG/TrxG protein recruitment remain unknown, the important role is suggested to belong to sequence-specific DNA-binding factors. At the same time, it was demonstrated that the PRE DNA-binding proteins are not exclusively localized to PREs but can bind other DNA regulatory elements, including enhancers, promoters, and boundaries. To gain an insight into the PRE DNA-binding protein regulatory network, here, using ChIP-seq and immuno-affinity purification coupled to the high-throughput mass spectrometry, we searched for differences in abundance of the Combgap, Zeste, Psq, and Adf1 PRE DNA-binding proteins. While there were no conspicuous differences in co-localization of these proteins with other functional transcription factors, we show that Combgap and Zeste are more tightly associated with the Polycomb repressive complex 1 (PRC1), while Psq interacts strongly with the TrxG proteins, including the BAP SWI/SNF complex. The Adf1 interactome contained Mediator subunits as the top interactors. In addition, Combgap efficiently interacted with AGO2, NELF, and TFIID. Combgap, Psq, and Adf1 have architectural proteins in their networks. We further investigated the existence of direct interactions between different PRE DNA-binding proteins and demonstrated that Combgap-Adf1, Psq-Dsp1, and Pho-Spps can interact in the yeast two-hybrid assay. Overall, our data suggest that Combgap, Psq, Zeste, and Adf1 are associated with the protein complexes implicated in different regulatory activities and indicate their potential multifunctional role in the regulation of transcription.
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Affiliation(s)
- Darya Chetverina
- Group of Epigenetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow, 119334, Russia.
| | - Nadezhda E Vorobyeva
- Group of Dynamics of Transcriptional Complexes, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Marina Yu Mazina
- Group of Hormone-Dependent Transcriptional Regulation, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Lika V Fab
- Group of Chromatin Biology, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow, 119334, Russia
| | - Dmitry Lomaev
- Group of Epigenetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow, 119334, Russia
| | - Alexandra Golovnina
- Group of Epigenetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow, 119334, Russia
| | - Vladic Mogila
- Department of Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow, 119334, Russia
| | - Pavel Georgiev
- Department of Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow, 119334, Russia
| | - Rustam H Ziganshin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Maksim Erokhin
- Group of Chromatin Biology, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow, 119334, Russia.
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27
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Bi CL, Cheng Q, Yan LY, Wu HY, Wang Q, Wang P, Cheng L, Wang R, Yang L, Li J, Tie F, Xie H, Fang M. A prominent gene activation role for C-terminal binding protein in mediating PcG/trxG proteins through Hox gene regulation. Development 2022; 149:275613. [DOI: 10.1242/dev.200153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 04/28/2022] [Indexed: 11/20/2022]
Abstract
ABSTRACT
The evolutionarily conserved C-terminal binding protein (CtBP) has been well characterized as a transcriptional co-repressor. Herein, we report a previously unreported function for CtBP, showing that lowering CtBP dosage genetically suppresses Polycomb group (PcG) loss-of-function phenotypes while enhancing that of trithorax group (trxG) in Drosophila, suggesting that the role of CtBP in gene activation is more pronounced in fly development than previously thought. In fly cells, we show that CtBP is required for the derepression of the most direct PcG target genes, which are highly enriched by homeobox transcription factors, including Hox genes. Using ChIP and co-IP assays, we demonstrate that CtBP is directly required for the molecular switch between H3K27me3 and H3K27ac in the derepressed Hox loci. In addition, CtBP physically interacts with many proteins, such as UTX, CBP, Fs(1)h and RNA Pol II, that have activation roles, potentially assisting in their recruitment to promoters and Polycomb response elements that control Hox gene expression. Therefore, we reveal a prominent activation function for CtBP that confers a major role for the epigenetic program of fly segmentation and development.
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Affiliation(s)
- Cai-Li Bi
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases, Southeast University 1 , Nanjing 210096 , China
- Institute of Translational Medicine 2 , , , Yangzhou 225001 , China
- Medical College 2 , , , Yangzhou 225001 , China
- Yangzhou University 2 , , , Yangzhou 225001 , China
| | - Qian Cheng
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases, Southeast University 1 , Nanjing 210096 , China
| | - Ling-Yue Yan
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases, Southeast University 1 , Nanjing 210096 , China
| | - Hong-Yan Wu
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases, Southeast University 1 , Nanjing 210096 , China
| | - Qiang Wang
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases, Southeast University 1 , Nanjing 210096 , China
| | - Ping Wang
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases, Southeast University 1 , Nanjing 210096 , China
| | - Lin Cheng
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases, Southeast University 1 , Nanjing 210096 , China
| | - Rui Wang
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases, Southeast University 1 , Nanjing 210096 , China
| | - Lin Yang
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases, Southeast University 1 , Nanjing 210096 , China
| | - Jian Li
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases, Southeast University 1 , Nanjing 210096 , China
| | - Feng Tie
- Case Western Reserve University 3 Department of Genetics and Genome Sciences , , Cleveland, OH 44106, USA
| | - Hao Xie
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases, Southeast University 1 , Nanjing 210096 , China
| | - Ming Fang
- School of Life Science and Technology, MOE Key Laboratory of Developmental Genes and Human Diseases, Southeast University 1 , Nanjing 210096 , China
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28
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Godwin J, Farrona S. The Importance of Networking: Plant Polycomb Repressive Complex 2 and Its Interactors. EPIGENOMES 2022; 6:epigenomes6010008. [PMID: 35323212 PMCID: PMC8948837 DOI: 10.3390/epigenomes6010008] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 12/13/2022] Open
Abstract
Polycomb Repressive Complex 2 (PRC2) is arguably the best-known plant complex of the Polycomb Group (PcG) pathway, formed by a group of proteins that epigenetically represses gene expression. PRC2-mediated deposition of H3K27me3 has amply been studied in Arabidopsis and, more recently, data from other plant model species has also been published, allowing for an increasing knowledge of PRC2 activities and target genes. How PRC2 molecular functions are regulated and how PRC2 is recruited to discrete chromatin regions are questions that have brought more attention in recent years. A mechanism to modulate PRC2-mediated activity is through its interaction with other protein partners or accessory proteins. Current evidence for PRC2 interactors has demonstrated the complexity of its protein network and how far we are from fully understanding the impact of these interactions on the activities of PRC2 core subunits and on the formation of new PRC2 versions. This review presents a list of PRC2 interactors, emphasizing their mechanistic action upon PRC2 functions and their effects on transcriptional regulation.
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29
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Hafer TL, Patra S, Tagami D, Kohwi M. Enhancer of trithorax/polycomb, Corto, regulates timing of hunchback gene relocation and competence in Drosophila neuroblasts. Neural Dev 2022; 17:3. [PMID: 35177098 PMCID: PMC8855600 DOI: 10.1186/s13064-022-00159-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 01/27/2022] [Indexed: 12/27/2022] Open
Abstract
Background Neural progenitors produce diverse cells in a stereotyped birth order, but can specify each cell type for only a limited duration. In the Drosophila embryo, neuroblasts (neural progenitors) specify multiple, distinct neurons by sequentially expressing a series of temporal identity transcription factors with each division. Hunchback (Hb), the first of the series, specifies early-born neuronal identity. Neuroblast competence to generate early-born neurons is terminated when the hb gene relocates to the neuroblast nuclear lamina, rendering it refractory to activation in descendent neurons. Mechanisms and trans-acting factors underlying this process are poorly understood. Here we identify Corto, an enhancer of Trithorax/Polycomb (ETP) protein, as a new regulator of neuroblast competence. Methods We used the GAL4/UAS system to drive persistent misexpression of Hb in neuroblast 7–1 (NB7-1), a model lineage for which the early competence window has been well characterized, to examine the role of Corto in neuroblast competence. We used immuno-DNA Fluorescence in situ hybridization (DNA FISH) in whole embryos to track the position of the hb gene locus specifically in neuroblasts across developmental time, comparing corto mutants to control embryos. Finally, we used immunostaining in whole embryos to examine Corto’s role in repression of Hb and a known target gene, Abdominal B (Abd-B). Results We found that in corto mutants, the hb gene relocation to the neuroblast nuclear lamina is delayed and the early competence window is extended. The delay in gene relocation occurs after hb transcription is already terminated in the neuroblast and is not due to prolonged transcriptional activity. Further, we find that Corto genetically interacts with Posterior Sex Combs (Psc), a core subunit of polycomb group complex 1 (PRC1), to terminate early competence. Loss of Corto does not result in derepression of Hb or its Hox target, Abd-B, specifically in neuroblasts. Conclusions These results show that in neuroblasts, Corto genetically interacts with PRC1 to regulate timing of nuclear architecture reorganization and support the model that distinct mechanisms of silencing are implemented in a step-wise fashion during development to regulate cell fate gene expression in neuronal progeny. Supplementary Information The online version contains supplementary material available at 10.1186/s13064-022-00159-3.
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Affiliation(s)
- Terry L Hafer
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY, 10027, USA.,Present Address: Molecular and Cellular Biology Program, University of Washington, Seattle, WA, 98195, USA
| | - Sofiya Patra
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY, 10027, USA
| | - Daiki Tagami
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY, 10027, USA
| | - Minoree Kohwi
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY, 10027, USA. .,Kavli Institute for Brain Science, Columbia University, New York, NY, 10027, USA.
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30
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Vijayanathan M, Trejo-Arellano MG, Mozgová I. Polycomb Repressive Complex 2 in Eukaryotes-An Evolutionary Perspective. EPIGENOMES 2022; 6:3. [PMID: 35076495 PMCID: PMC8788455 DOI: 10.3390/epigenomes6010003] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 01/12/2022] [Accepted: 01/12/2022] [Indexed: 12/23/2022] Open
Abstract
Polycomb repressive complex 2 (PRC2) represents a group of evolutionarily conserved multi-subunit complexes that repress gene transcription by introducing trimethylation of lysine 27 on histone 3 (H3K27me3). PRC2 activity is of key importance for cell identity specification and developmental phase transitions in animals and plants. The composition, biochemistry, and developmental function of PRC2 in animal and flowering plant model species are relatively well described. Recent evidence demonstrates the presence of PRC2 complexes in various eukaryotic supergroups, suggesting conservation of the complex and its function. Here, we provide an overview of the current understanding of PRC2-mediated repression in different representatives of eukaryotic supergroups with a focus on the green lineage. By comparison of PRC2 in different eukaryotes, we highlight the possible common and diverged features suggesting evolutionary implications and outline emerging questions and directions for future research of polycomb repression and its evolution.
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Affiliation(s)
- Mallika Vijayanathan
- Biology Centre, Institute of Plant Molecular Biology, Czech Academy of Sciences, 370 05 Ceske Budejovice, Czech Republic; (M.V.); (M.G.T.-A.)
| | - María Guadalupe Trejo-Arellano
- Biology Centre, Institute of Plant Molecular Biology, Czech Academy of Sciences, 370 05 Ceske Budejovice, Czech Republic; (M.V.); (M.G.T.-A.)
| | - Iva Mozgová
- Biology Centre, Institute of Plant Molecular Biology, Czech Academy of Sciences, 370 05 Ceske Budejovice, Czech Republic; (M.V.); (M.G.T.-A.)
- Faculty of Science, University of South Bohemia, 370 05 Ceske Budejovice, Czech Republic
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31
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Blackledge NP, Klose RJ. The molecular principles of gene regulation by Polycomb repressive complexes. Nat Rev Mol Cell Biol 2021; 22:815-833. [PMID: 34400841 PMCID: PMC7612013 DOI: 10.1038/s41580-021-00398-y] [Citation(s) in RCA: 170] [Impact Index Per Article: 56.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2021] [Indexed: 12/12/2022]
Abstract
Precise control of gene expression is fundamental to cell function and development. Although ultimately gene expression relies on DNA-binding transcription factors to guide the activity of the transcription machinery to genes, it has also become clear that chromatin and histone post-translational modification have fundamental roles in gene regulation. Polycomb repressive complexes represent a paradigm of chromatin-based gene regulation in animals. The Polycomb repressive system comprises two central protein complexes, Polycomb repressive complex 1 (PRC1) and PRC2, which are essential for normal gene regulation and development. Our early understanding of Polycomb function relied on studies in simple model organisms, but more recently it has become apparent that this system has expanded and diverged in mammals. Detailed studies are now uncovering the molecular mechanisms that enable mammalian PRC1 and PRC2 to identify their target sites in the genome, communicate through feedback mechanisms to create Polycomb chromatin domains and control transcription to regulate gene expression. In this Review, we discuss and contextualize the emerging principles that define how this fascinating chromatin-based system regulates gene expression in mammals.
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Affiliation(s)
| | - Robert J Klose
- Department of Biochemistry, University of Oxford, Oxford, UK.
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32
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Han S, Basting PJ, Dias GB, Luhur A, Zelhof AC, Bergman CM. Transposable element profiles reveal cell line identity and loss of heterozygosity in Drosophila cell culture. Genetics 2021; 219:6321957. [PMID: 34849875 PMCID: PMC8633141 DOI: 10.1093/genetics/iyab113] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 07/01/2021] [Indexed: 11/28/2022] Open
Abstract
Cell culture systems allow key insights into biological mechanisms yet suffer from irreproducible outcomes in part because of cross-contamination or mislabeling of cell lines. Cell line misidentification can be mitigated by the use of genotyping protocols, which have been developed for human cell lines but are lacking for many important model species. Here, we leverage the classical observation that transposable elements (TEs) proliferate in cultured Drosophila cells to demonstrate that genome-wide TE insertion profiles can reveal the identity and provenance of Drosophila cell lines. We identify multiple cases where TE profiles clarify the origin of Drosophila cell lines (Sg4, mbn2, and OSS_E) relative to published reports, and also provide evidence that insertions from only a subset of long-terminal repeat retrotransposon families are necessary to mark Drosophila cell line identity. We also develop a new bioinformatics approach to detect TE insertions and estimate intra-sample allele frequencies in legacy whole-genome sequencing data (called ngs_te_mapper2), which revealed loss of heterozygosity as a mechanism shaping the unique TE profiles that identify Drosophila cell lines. Our work contributes to the general understanding of the forces impacting metazoan genomes as they evolve in cell culture and paves the way for high-throughput protocols that use TE insertions to authenticate cell lines in Drosophila and other organisms.
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Affiliation(s)
- Shunhua Han
- Department of Genetics and Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
| | - Preston J Basting
- Department of Genetics and Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
| | - Guilherme B Dias
- Department of Genetics and Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA.,Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Arthur Luhur
- Drosophila Genomics Resource Center, Indiana University, Bloomington, IN 47405, USA.,Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Andrew C Zelhof
- Drosophila Genomics Resource Center, Indiana University, Bloomington, IN 47405, USA.,Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Casey M Bergman
- Department of Genetics and Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA.,Department of Genetics, University of Georgia, Athens, GA 30602, USA
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33
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Lucas T, Hafer TL, Zhang HG, Molotkova N, Kohwi M. Discrete cis-acting element regulates developmentally timed gene-lamina relocation and neural progenitor competence in vivo. Dev Cell 2021; 56:2649-2663.e6. [PMID: 34529940 PMCID: PMC8629127 DOI: 10.1016/j.devcel.2021.08.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 06/24/2021] [Accepted: 08/20/2021] [Indexed: 01/21/2023]
Abstract
The nuclear lamina is typically associated with transcriptional silencing, and peripheral relocation of genes highly correlates with repression. However, the DNA sequences and proteins regulating gene-lamina interactions are largely unknown. Exploiting the developmentally timed hunchback gene movement to the lamina in Drosophila neuroblasts, we identified a 250 bp intronic element (IE) both necessary and sufficient for relocation. The IE can target a reporter transgene to the lamina and silence it. Endogenously, however, hunchback is already repressed prior to relocation. Instead, IE-mediated relocation confers a heritably silenced gene state refractory to activation in descendent neurons, which terminates neuroblast competence to specify early-born identity. Surprisingly, we found that the Polycomb group chromatin factors bind the IE and are required for lamina relocation, revealing a nuclear architectural role distinct from their well-known function in transcriptional repression. Together, our results uncover in vivo mechanisms underlying neuroblast competence and lamina association in heritable gene silencing. In Drosophila neuroblasts, relocation of the hunchback gene locus to the nuclear lamina confers heritable silencing in daughter neurons. Lucas et al. identify a genomic element necessary and sufficient for hunchback gene movement in vivo. Polycomb proteins target this element for lamina relocation, thereby regulating competence, but not hunchback expression.
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Affiliation(s)
- Tanguy Lucas
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY 10027, USA
| | - Terry L Hafer
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY 10027, USA
| | - Harrison G Zhang
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY 10027, USA
| | - Natalia Molotkova
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY 10027, USA
| | - Minoree Kohwi
- Department of Neuroscience, Mortimer B. Zuckerman Institute Mind Brain Behavior, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA.
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Zoroddu S, Marchesi I, Bagella L. PRC2: an epigenetic multiprotein complex with a key role in the development of rhabdomyosarcoma carcinogenesis. Clin Epigenetics 2021; 13:156. [PMID: 34372908 PMCID: PMC8351429 DOI: 10.1186/s13148-021-01147-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/02/2021] [Indexed: 02/02/2023] Open
Abstract
Skeletal muscle formation represents a complex of highly organized and specialized systems that are still not fully understood. Epigenetic systems underline embryonic development, maintenance of stemness, and progression of differentiation. Polycomb group proteins play the role of gene silencing of stemness markers that regulate muscle differentiation. Enhancer of Zeste EZH2 is the catalytic subunit of the complex that is able to trimethylate lysine 27 of histone H3 and induce silencing of the involved genes. In embryonal Rhabdomyosarcoma and several other tumors, EZH2 is often deregulated and, in some cases, is associated with tumor malignancy. This review explores the molecular processes underlying the failure of muscle differentiation with a focus on the PRC2 complex. These considerations could open new studies aimed at the development of new cutting-edge therapeutic strategies in the onset of Rhabdomyosarcoma.
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Affiliation(s)
- Stefano Zoroddu
- Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/b, 07100, Sassari, Italy
| | - Irene Marchesi
- Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/b, 07100, Sassari, Italy
- Kitos Biotech Srls, Tramariglio, Alghero, SS, Italy
| | - Luigi Bagella
- Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/b, 07100, Sassari, Italy.
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, USA.
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35
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Shen Q, Lin Y, Li Y, Wang G. Dynamics of H3K27me3 Modification on Plant Adaptation to Environmental Cues. PLANTS 2021; 10:plants10061165. [PMID: 34201297 PMCID: PMC8228231 DOI: 10.3390/plants10061165] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/30/2021] [Accepted: 06/01/2021] [Indexed: 12/13/2022]
Abstract
Given their sessile nature, plants have evolved sophisticated regulatory networks to confer developmental plasticity for adaptation to fluctuating environments. Epigenetic codes, like tri-methylation of histone H3 on Lys27 (H3K27me3), are evidenced to account for this evolutionary benefit. Polycomb repressive complex 2 (PRC2) and PRC1 implement and maintain the H3K27me3-mediated gene repression in most eukaryotic cells. Plants take advantage of this epigenetic machinery to reprogram gene expression in development and environmental adaption. Recent studies have uncovered a number of new players involved in the establishment, erasure, and regulation of H3K27me3 mark in plants, particularly highlighting new roles in plants’ responses to environmental cues. Here, we review current knowledge on PRC2-H3K27me3 dynamics occurring during plant growth and development, including its writers, erasers, and readers, as well as targeting mechanisms, and summarize the emerging roles of H3K27me3 mark in plant adaptation to environmental stresses.
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36
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Fujioka M, Nezdyur A, Jaynes JB. An insulator blocks access to enhancers by an illegitimate promoter, preventing repression by transcriptional interference. PLoS Genet 2021; 17:e1009536. [PMID: 33901190 PMCID: PMC8102011 DOI: 10.1371/journal.pgen.1009536] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 05/06/2021] [Accepted: 04/06/2021] [Indexed: 01/09/2023] Open
Abstract
Several distinct activities and functions have been described for chromatin insulators, which separate genes along chromosomes into functional units. Here, we describe a novel mechanism of functional separation whereby an insulator prevents gene repression. When the homie insulator is deleted from the end of a Drosophila even skipped (eve) locus, a flanking P-element promoter is activated in a partial eve pattern, causing expression driven by enhancers in the 3’ region to be repressed. The mechanism involves transcriptional read-through from the flanking promoter. This conclusion is based on the following. Read-through driven by a heterologous enhancer is sufficient to repress, even when homie is in place. Furthermore, when the flanking promoter is turned around, repression is minimal. Transcriptional read-through that does not produce anti-sense RNA can still repress expression, ruling out RNAi as the mechanism in this case. Thus, transcriptional interference, caused by enhancer capture and read-through when the insulator is removed, represses eve promoter-driven expression. We also show that enhancer-promoter specificity and processivity of transcription can have decisive effects on the consequences of insulator removal. First, a core heat shock 70 promoter that is not activated well by eve enhancers did not cause read-through sufficient to repress the eve promoter. Second, these transcripts are less processive than those initiated at the P-promoter, measured by how far they extend through the eve locus, and so are less disruptive. These results highlight the importance of considering transcriptional read-through when assessing the effects of insulators on gene expression. Several distinct activities and functions have been described for chromatin insulators, which are regulatory DNA elements that separate genes along chromosomes into functional units. Here, we describe how insulators can prevent repression of one gene by preventing inappropriate transcription of another gene, without blocking read-through of transcription per se. When the insulator homie is deleted from the end of a transgenic eve locus, a flanking transposable element promoter is activated by eve enhancers, causing repression of the eve promoter. The mechanism involves transcriptional read-through from the flanking promoter, which disrupts normal eve enhancer-promoter activities. When the flanking promoter is turned around, repression of eve is minimal. Thus, transcriptional interference, caused by enhancer capture and read-through when the insulator is removed, represses the eve promoter. These results show a novel role for transcriptional read-through in the effects of insulators on gene expression.
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Affiliation(s)
- Miki Fujioka
- Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Anastasiya Nezdyur
- Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - James B. Jaynes
- Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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37
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The Role of Polycomb Group Protein BMI1 in DNA Repair and Genomic Stability. Int J Mol Sci 2021; 22:ijms22062976. [PMID: 33804165 PMCID: PMC7998361 DOI: 10.3390/ijms22062976] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 03/09/2021] [Indexed: 12/31/2022] Open
Abstract
The polycomb group (PcG) proteins are a class of transcriptional repressors that mediate gene silencing through histone post-translational modifications. They are involved in the maintenance of stem cell self-renewal and proliferation, processes that are often dysregulated in cancer. Apart from their canonical functions in epigenetic gene silencing, several studies have uncovered a function for PcG proteins in DNA damage signaling and repair. In particular, members of the poly-comb group complexes (PRC) 1 and 2 have been shown to recruit to sites of DNA damage and mediate DNA double-strand break repair. Here, we review current understanding of the PRCs and their roles in cancer development. We then focus on the PRC1 member BMI1, discussing the current state of knowledge of its role in DNA repair and genome integrity, and outline how it can be targeted pharmacologically.
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Pyziak K, Sroka-Porada A, Rzymski T, Dulak J, Łoboda A. Potential of enhancer of zeste homolog 2 inhibitors for the treatment of SWI/SNF mutant cancers and tumor microenvironment modulation. Drug Dev Res 2021; 82:730-753. [PMID: 33565092 DOI: 10.1002/ddr.21796] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/13/2021] [Accepted: 01/18/2021] [Indexed: 12/17/2022]
Abstract
Enhancer of zeste homolog 2 (EZH2), a catalytic component of polycomb repressive complex 2 (PRC2), is commonly overexpressed or mutated in many cancer types, both of hematological and solid nature. Till now, plenty of EZH2 small molecule inhibitors have been developed and some of them have already been tested in clinical trials. Most of these inhibitors, however, are effective only in limited cases in the context of EZH2 gain-of-function mutated tumors such as lymphomas. Other cancer types with aberrant EZH2 expression and function require alternative approaches for successful treatment. One possibility is to exploit synthetic lethal strategy, which is based on the phenomenon that concurrent loss of two genes is detrimental but the deletion of either of them leaves cell viable. In the context of EZH2/PRC2, the most promising synthetic lethal target seems to be SWItch/Sucrose Non-Fermentable chromatin remodeling complex (SWI/SNF), which is known to counteract PRC2 functions. SWI/SNF is heavily involved in carcinogenesis and its subunits have been found mutated in approximately 20% of tumors of different kinds. In the current review, we summarize the existing knowledge of synthetic lethal relationships between EZH2/PRC2 and components of the SWI/SNF complex and discuss in detail the potential application of existing EZH2 inhibitors in cancer patients harboring mutations in SWI/SNF proteins. We also highlight recent discoveries of EZH2 involvement in tumor microenvironment regulation and consequences for future therapies. Although clinical studies are limited, the fundamental research might help to understand which patients are most likely to benefit from therapies using EZH2 inhibitors.
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Affiliation(s)
- Karolina Pyziak
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland.,Biology R&D, Ryvu Therapeutics S.A., Kraków, Poland
| | | | | | - Józef Dulak
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Agnieszka Łoboda
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
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Liu L, Hyeon C. Revisiting the organization of Polycomb-repressed domains: 3D chromatin models from Hi-C compared with super-resolution imaging. Nucleic Acids Res 2021; 48:11486-11494. [PMID: 33095877 PMCID: PMC7672452 DOI: 10.1093/nar/gkaa932] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 09/22/2020] [Accepted: 10/06/2020] [Indexed: 01/07/2023] Open
Abstract
The accessibility of target gene, a factor critical for gene regulation, is controlled by epigenetic fine-tuning of chromatin organization. While there are multiple experimental techniques to study change of chromatin architecture with its epigenetic state, measurements from them are not always complementary. A qualitative discrepancy is noted between recent super-resolution imaging studies, particularly on Polycomb-group protein repressed domains in Drosophila cell. One of the studies shows that Polycomb-repressed domains are more compact than inactive domains and are segregated from neighboring active domains, whereas Hi-C and chromatin accessibility assay as well as the other super-resolution imaging studies paint a different picture. To examine this issue in detail, we analyzed Hi-C libraries of Drosophila chromosomes as well as distance constraints from one of the imaging studies, and modeled different epigenetic domains by employing a polymer-based approach. According to our chromosome models, both Polycomb-repressed and inactive domains are featured with a similar degree of intra-domain packaging and significant intermixing with adjacent active domains. The epigenetic domains explicitly visualized by our polymer model call for extra attention to the discrepancy of the super-resolution imaging with other measurements, although its precise physicochemical origin still remains to be elucidated.
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Affiliation(s)
- Lei Liu
- Department of Physics, Zhejiang Sci-Tech University, Hangzhou 310018, People's Republic of China
| | - Changbong Hyeon
- Korea Institute for Advanced Study, Seoul 02455, Republic of Korea
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Farcas AM, Nagarajan S, Cosulich S, Carroll JS. Genome-Wide Estrogen Receptor Activity in Breast Cancer. Endocrinology 2021; 162:bqaa224. [PMID: 33284960 PMCID: PMC7787425 DOI: 10.1210/endocr/bqaa224] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Indexed: 12/13/2022]
Abstract
The largest subtype of breast cancer is characterized by the expression and activity of the estrogen receptor alpha (ERalpha/ER). Although several effective therapies have significantly improved survival, the adaptability of cancer cells means that patients frequently stop responding or develop resistance to endocrine treatment. ER does not function in isolation and multiple associating factors have been reported to play a role in regulating the estrogen-driven transcriptional program. This review focuses on the dynamic interplay between some of these factors which co-occupy ER-bound regulatory elements, their contribution to estrogen signaling, and their possible therapeutic applications. Furthermore, the review illustrates how some ER association partners can influence and reprogram the genomic distribution of the estrogen receptor. As this dynamic ER activity enables cancer cell adaptability and impacts the clinical outcome, defining how this plasticity is determined is fundamental to our understanding of the mechanisms of disease progression.
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Affiliation(s)
- Anca M Farcas
- Bioscience, Oncology R&D, AstraZeneca, Cambridge, UK
- CRUK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Sankari Nagarajan
- CRUK Cambridge Institute, University of Cambridge, Cambridge, UK
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | | | - Jason S Carroll
- CRUK Cambridge Institute, University of Cambridge, Cambridge, UK
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Drosophila Hox genes induce melanized pseudo-tumors when misexpressed in hemocytes. Sci Rep 2021; 11:1838. [PMID: 33469139 PMCID: PMC7815749 DOI: 10.1038/s41598-021-81472-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Accepted: 01/07/2021] [Indexed: 12/17/2022] Open
Abstract
Hox genes are early determinants of cell identity along the anterior–posterior body axis across bilaterians. Several late non-homeotic functions of Hox genes have emerged in a variety of processes involved in organogenesis in several organisms, including mammals. Several studies have reported the misexpression of Hox genes in a variety of malignancies including acute myeloid leukemia. The Hox genes Dfd, Ubx, abd-A and Abd-B were overexpressed via the UAS-Gal4 system using Cg-Gal4, Lsp2-Gal4, He-Gal4 and HmlD3-Gal4 as specific drivers. Genetic interaction was tested by bringing overexpression lines in heterozygous mutant backgrounds of Polycomb and trithorax group factors. Larvae were visually scored for melanized bodies. Circulating hemocytes were quantified and tested for differentiation. Pupal lethality was assessed. Expression of Dfd, Ubx and abd-A, but not Abd-B in the hematopoietic compartment of Drosophila led to the appearance of circulating melanized bodies, an increase in cell number, cell-autonomous proliferation, and differentiation of hemocytes. Pupal lethality and melanized pseudo-tumors were suppressed in Psc1 and esc2 backgrounds while polycomb group member mutations Pc1 and Su(z)123 and trithorax group member mutation TrlR85 enhanced the phenotype. Dfd, Ubx and abd-A are leukemogenic. Mutations in Polycomb and trithorax group members modulate the leukemogenic phenotype. Our RNAseq of Cg-Gal4 > UAS-abd-A hemocytes may contain genes important to Hox gene induced leukemias.
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Abstract
The Genetics Society of America's (GSA's) Edward Novitski Prize recognizes a single experimental accomplishment or a body of work in which an exceptional level of creativity, and intellectual ingenuity, has been used to design and execute scientific experiments to solve a difficult problem in genetics. The 2020 recipient is Welcome W. Bender of Harvard Medical School, recognizing his creativity and ingenuity in revealing the molecular nature and regulation of the bithorax gene complex.
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Broad genic repression domains signify enhanced silencing of oncogenes. Nat Commun 2020; 11:5560. [PMID: 33144558 PMCID: PMC7641226 DOI: 10.1038/s41467-020-18913-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 09/18/2020] [Indexed: 01/01/2023] Open
Abstract
Cancers result from a set of genetic and epigenetic alterations. Most known oncogenes were identified by gain-of-function mutations in cancer, yet little is known about their epigenetic features. Through integrative analysis of 11,596 epigenomic profiles and mutations from >8200 tumor-normal pairs, we discover broad genic repression domains (BGRD) on chromatin as an epigenetic signature for oncogenes. A BGRD is a widespread enrichment domain of the repressive histone modification H3K27me3 and is further enriched with multiple other repressive marks including H3K9me3, H3K9me2, and H3K27me2. Further, BGRD displays widespread enrichment of repressed cis-regulatory elements. Shortening of BGRDs is linked to derepression of transcription. BGRDs at oncogenes tend to be conserved across normal cell types. Putative tumor-promoting genes and lncRNAs defined using BGRDs are experimentally verified as required for cancer phenotypes. Therefore, BGRDs play key roles in epigenetic regulation of cancer and provide a direction for mutation-independent discovery of oncogenes. Epigenetically altered genes can have a key role in cancer pathobiology but epigenetic signatures that distinguish oncogenes are not yet known. Here, the authors identify broad genic repression domains, defined by widespread H3K27me3 modification, as an epigenetic signature to provide mutation-independent information for discovery of potential oncogenes.
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Nucleosome Positioning Regulates the Establishment, Stability, and Inheritance of Heterochromatin in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 2020; 117:27493-27501. [PMID: 33077593 DOI: 10.1073/pnas.2004111117] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Heterochromatic domains are complex structures composed of nucleosome arrays that are bound by silencing factors. This composition raises the possibility that certain configurations of nucleosome arrays facilitate heterochromatic silencing. We tested this possibility in Saccharomyces cerevisiae by systematically altering the distance between heterochromatic nucleosome-depleted regions (NDRs), which is predicted to affect local nucleosome positioning by limiting how nucleosomes can be packed between NDRs. Consistent with this prediction, serial deletions that altered the distance between heterochromatic NDRs revealed a striking oscillatory relationship between inter-NDR distance and defects in nucleosome positioning. Furthermore, conditions that caused poor nucleosome positioning also led to defects in both heterochromatin stability and the ability of cells to generate and inherit epigenetic transcriptional states. These findings strongly suggest that nucleosome positioning can contribute to formation and maintenance of functional heterochromatin and point to previously unappreciated roles of NDR positioning within heterochromatic domains.
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Martin CJ, Moorehead RA. Polycomb repressor complex 2 function in breast cancer (Review). Int J Oncol 2020; 57:1085-1094. [PMID: 33491744 PMCID: PMC7549536 DOI: 10.3892/ijo.2020.5122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 09/07/2020] [Indexed: 11/24/2022] Open
Abstract
Epigenetic modifications are important contributors to the regulation of genes within the chromatin. The polycomb repressive complex 2 (PRC2) is a multi‑subunit protein complex that is involved in silencing gene expression through the trimethylation of lysine 27 at histone 3 (H3K27me3). The dysregulation of this modification has been associated with tumorigenicity through the increased repression of tumour suppressor genes via condensing DNA to reduce access to the transcription start site (TSS) within tumor suppressor gene promoters. In the present review, the core proteins of PRC2, as well as key accessory proteins, will be described. In addition, mechanisms controlling the recruitment of the PRC2 complex to H3K27 will be outlined. Finally, literature identifying the role of PRC2 in breast cancer proliferation, apoptosis and migration, including the potential roles of long non‑coding RNAs and the miR‑200 family will be summarized as will the potential use of the PRC2 complex as a therapeutic target.
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Affiliation(s)
- Courtney J. Martin
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON N1G2W1, Canada
| | - Roger A. Moorehead
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON N1G2W1, Canada
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Chetverina DA, Lomaev DV, Erokhin MM. Polycomb and Trithorax Group Proteins: The Long Road from Mutations in Drosophila to Use in Medicine. Acta Naturae 2020; 12:66-85. [PMID: 33456979 PMCID: PMC7800605 DOI: 10.32607/actanaturae.11090] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/30/2020] [Indexed: 12/12/2022] Open
Abstract
Polycomb group (PcG) and Trithorax group (TrxG) proteins are evolutionarily conserved factors responsible for the repression and activation of the transcription of multiple genes in Drosophila and mammals. Disruption of the PcG/TrxG expression is associated with many pathological conditions, including cancer, which makes them suitable targets for diagnosis and therapy in medicine. In this review, we focus on the major PcG and TrxG complexes, the mechanisms of PcG/TrxG action, and their recruitment to chromatin. We discuss the alterations associated with the dysfunction of a number of factors of these groups in oncology and the current strategies used to develop drugs based on small-molecule inhibitors.
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Affiliation(s)
- D. A. Chetverina
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334 Russia
| | - D. V. Lomaev
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334 Russia
| | - M. M. Erokhin
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334 Russia
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Son W, Choi KW. The Classic Lobe Eye Phenotype of Drosophila Is Caused by Transposon Insertion-Induced Misexpression of a Zinc-Finger Transcription Factor. Genetics 2020; 216:117-134. [PMID: 32641295 PMCID: PMC7463288 DOI: 10.1534/genetics.120.303486] [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: 08/02/2019] [Accepted: 07/06/2020] [Indexed: 11/18/2022] Open
Abstract
Drosophila Lobe (L) alleles were first discovered ∼100 years ago as spontaneous dominant mutants with characteristic developmental eye defects. However, the molecular basis for L dominant eye phenotypes has not been clearly understood. A previous work reported identification of CG10109/PRAS40 as the L gene, but subsequent analyses suggested that PRAS40 may not be related to L Here, we revisited the L gene to clarify this discrepancy and understand the basis for the dominance of L mutations. Genetic analysis localized the L gene to Oaz, which encodes a homolog of the vertebrate zinc finger protein 423 (Zfp423) family transcriptional regulators. We demonstrate that RNAi knockdown of Oaz almost completely restores all L dominant alleles tested. Lrev6-3 , a revertant allele of the L2 dominant eye phenotype, has an inframe deletion in the Oaz coding sequence. Molecular analysis of L dominant mutants identified allele-specific insertions of natural transposons (roo[ ]L1 , hopper[ ]L5 , and roo[ ]Lr ) or alterations of a preexisting transposon (L2 -specific mutations in roo[ ]Mohr) in the Oaz region. In addition, we generated additional L2 -reversion alleles by CRISPR targeting at Oaz These new loss-of-function Oaz mutations suppress the dominant L eye phenotype. Oaz protein is not expressed in wild-type eye disc but is expressed ectopically in L2/+ mutant eye disc. We induced male recombination between Oaz-GAL4 insertions and the L2 mutation through homologous recombination. By using the L2 -recombined GAL4 reporters, we show that Oaz-GAL4 is expressed ectopically in L2 eye imaginal disc. Taken together, our data suggest that neomorphic L eye phenotypes are likely due to misregulation of Oaz by spontaneous transposon insertions.
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Affiliation(s)
- Wonseok Son
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Kwang-Wook Choi
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
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48
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Das P, Bhadra MP. Histone deacetylase (Rpd3) regulates Drosophila early brain development via regulation of Tailless. Open Biol 2020; 10:200029. [PMID: 32873153 PMCID: PMC7536075 DOI: 10.1098/rsob.200029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 07/29/2020] [Indexed: 11/29/2022] Open
Abstract
Tailless is a committed transcriptional repressor and principal regulator of the brain and eye development in Drosophila. Rpd3, the histone deacetylase, is an established repressor that interacts with co-repressors like Sin3a, Prospero, Brakeless and Atrophin. This study aims at deciphering the role of Rpd3 in embryonic segmentation and larval brain development in Drosophila. It delineates the mechanism of Tailless regulation by Rpd3, along with its interacting partners. There was a significant reduction in Tailless in Rpd3 heteroallelic mutant embryos, substantiating that Rpd3 is indispensable for the normal Tailless expression. The expression of the primary readout, Tailless was correlative to the expression of the neural cell adhesion molecule homologue, Fascilin2 (Fas2). Rpd3 also aids in the proper development of the mushroom body. Both Tailless and Fas2 expression are reported to be antagonistic to the epidermal growth factor receptor (EGFR) expression. The decrease in Tailless and Fas2 expression highlights that EGFR is upregulated in the larval mutants, hindering brain development. This study outlines the axis comprising Rpd3, dEGFR, Tailless and Fas2, which interact to fine-tune the early segmentation and larval brain development. Therefore, Rpd3 along with Tailless has immense significance in early embryogenesis and development of the larval brain.
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Affiliation(s)
- Paromita Das
- Applied Biology Division, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500 007, India
- Academy of Scientific and Innovative Research (AcSIR) Training and Development Complex, CSIR Campus, CSIR Road, Taramani, Chennai 600 113, India
| | - Manika Pal Bhadra
- Applied Biology Division, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500 007, India
- Academy of Scientific and Innovative Research (AcSIR) Training and Development Complex, CSIR Campus, CSIR Road, Taramani, Chennai 600 113, India
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Rivera RM. Consequences of assisted reproductive techniques on the embryonic epigenome in cattle. Reprod Fertil Dev 2020; 32:65-81. [PMID: 32188559 DOI: 10.1071/rd19276] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Procedures used in assisted reproduction have been under constant scrutiny since their inception with the goal of improving the number and quality of embryos produced. However, invitro production of embryos is not without complications because many fertilised oocytes fail to become blastocysts, and even those that do often differ in the genetic output compared with their invivo counterparts. Thus only a portion of those transferred complete normal fetal development. An unwanted consequence of bovine assisted reproductive technology (ART) is the induction of a syndrome characterised by fetal overgrowth and placental abnormalities, namely large offspring syndrome; a condition associated with inappropriate control of the epigenome. Epigenetics is the study of chromatin and its effects on genetic output. Establishment and maintenance of epigenetic marks during gametogenesis and embryogenesis is imperative for the maintenance of cell identity and function. ARTs are implemented during times of vast epigenetic reprogramming; as a result, many studies have identified ART-induced deviations in epigenetic regulation in mammalian gametes and embryos. This review describes the various layers of epigenetic regulation and discusses findings pertaining to the effects of ART on the epigenome of bovine gametes and the preimplantation embryo.
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Affiliation(s)
- Rocío Melissa Rivera
- Division of Animal Science University of Missouri, Columbia, Missouri 65211, USA.
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Giner-Laguarda N, Vidal M. Functions of Polycomb Proteins on Active Targets. EPIGENOMES 2020; 4:17. [PMID: 34968290 PMCID: PMC8594714 DOI: 10.3390/epigenomes4030017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 08/12/2020] [Accepted: 08/13/2020] [Indexed: 12/15/2022] Open
Abstract
Chromatin regulators of the Polycomb group of genes are well-known by their activities as transcriptional repressors. Characteristically, their presence at genomic sites occurs with specific histone modifications and sometimes high-order chromatin structures correlated with silencing of genes involved in cell differentiation. However, evidence gathered in recent years, on flies and mammals, shows that in addition to these sites, Polycomb products bind to a large number of active regulatory regions. Occupied sites include promoters and also intergenic regions, containing enhancers and super-enhancers. Contrasting with occupancies at repressed targets, characteristic histone modifications are low or undetectable. Functions on active targets are dual, restraining gene expression at some targets while promoting activity at others. Our aim here is to summarize the evidence available and discuss the convenience of broadening the scope of research to include Polycomb functions on active targets.
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Affiliation(s)
| | - Miguel Vidal
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, Ramiro de Maeztu 9, 28040 Madrid, Spain;
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