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Vorobyeva NE, Krasnov AN, Erokhin M, Chetverina D, Mazina M. Su(Hw) interacts with Combgap to establish long-range chromatin contacts. Epigenetics Chromatin 2024; 17:17. [PMID: 38773468 PMCID: PMC11106861 DOI: 10.1186/s13072-024-00541-x] [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: 01/29/2024] [Accepted: 05/16/2024] [Indexed: 05/23/2024] Open
Abstract
BACKGROUND Insulator-binding proteins (IBPs) play a critical role in genome architecture by forming and maintaining contact domains. While the involvement of several IBPs in organising chromatin architecture in Drosophila has been described, the specific contribution of the Suppressor of Hairy wings (Su(Hw)) insulator-binding protein to genome topology remains unclear. RESULTS In this study, we provide evidence for the existence of long-range interactions between chromatin bound Su(Hw) and Combgap, which was first characterised as Polycomb response elements binding protein. Loss of Su(Hw) binding to chromatin results in the disappearance of Su(Hw)-Combgap long-range interactions and in a decrease in spatial self-interactions among a subset of Su(Hw)-bound genome sites. Our findings suggest that Su(Hw)-Combgap long-range interactions are associated with active chromatin rather than Polycomb-directed repression. Furthermore, we observe that the majority of transcription start sites that are down-regulated upon loss of Su(Hw) binding to chromatin are located within 2 kb of Combgap peaks and exhibit Su(Hw)-dependent changes in Combgap and transcriptional regulators' binding. CONCLUSIONS This study demonstrates that Su(Hw) insulator binding protein can form long-range interactions with Combgap, Polycomb response elements binding protein, and that these interactions are associated with active chromatin factors rather than with Polycomb dependent repression.
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Affiliation(s)
- Nadezhda E Vorobyeva
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Alexey N Krasnov
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Maksim Erokhin
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Darya Chetverina
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Marina Mazina
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
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2
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Sokolov V, Kyrchanova O, Klimenko N, Fedotova A, Ibragimov A, Maksimenko O, Georgiev P. New Drosophila promoter-associated architectural protein Mzfp1 interacts with CP190 and is required for housekeeping gene expression and insulator activity. Nucleic Acids Res 2024:gkae393. [PMID: 38769058 DOI: 10.1093/nar/gkae393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 04/20/2024] [Accepted: 05/10/2024] [Indexed: 05/22/2024] Open
Abstract
In Drosophila, a group of zinc finger architectural proteins recruits the CP190 protein to the chromatin, an interaction that is essential for the functional activity of promoters and insulators. In this study, we describe a new architectural C2H2 protein called Madf and Zinc-Finger Protein 1 (Mzfp1) that interacts with CP190. Mzfp1 has an unusual structure that includes six C2H2 domains organized in a C-terminal cluster and two tandem MADF domains. Mzfp1 predominantly binds to housekeeping gene promoters located in both euchromatin and heterochromatin genome regions. In vivo mutagenesis studies showed that Mzfp1 is an essential protein, and both MADF domains and the CP190 interaction region are required for its functional activity. The C2H2 cluster is sufficient for the specific binding of Mzfp1 to regulatory elements, while the second MADF domain is required for Mzfp1 recruitment to heterochromatin. Mzfp1 binds to the proximal part of the Fub boundary that separates regulatory domains of the Ubx and abd-A genes in the Bithorax complex. Mzfp1 participates in Fub functions in cooperation with the architectural proteins Pita and Su(Hw). Thus, Mzfp1 is a new architectural C2H2 protein involved in the organization of active promoters and insulators in Drosophila.
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Affiliation(s)
- Vladimir Sokolov
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Olga Kyrchanova
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Natalia Klimenko
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Anna Fedotova
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Airat Ibragimov
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Oksana Maksimenko
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
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3
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Melnikova L, Molodina V, Georgiev P, Golovnin A. Development of a New Model System to Study Long-Distance Interactions Supported by Architectural Proteins. Int J Mol Sci 2024; 25:4617. [PMID: 38731837 PMCID: PMC11083095 DOI: 10.3390/ijms25094617] [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: 03/19/2024] [Revised: 04/20/2024] [Accepted: 04/21/2024] [Indexed: 05/13/2024] Open
Abstract
Chromatin architecture is critical for the temporal and tissue-specific activation of genes that determine eukaryotic development. The functional interaction between enhancers and promoters is controlled by insulators and tethering elements that support specific long-distance interactions. However, the mechanisms of the formation and maintenance of long-range interactions between genome regulatory elements remain poorly understood, primarily due to the lack of convenient model systems. Drosophila became the first model organism in which architectural proteins that determine the activity of insulators were described. In Drosophila, one of the best-studied DNA-binding architectural proteins, Su(Hw), forms a complex with Mod(mdg4)-67.2 and CP190 proteins. Using a combination of CRISPR/Cas9 genome editing and attP-dependent integration technologies, we created a model system in which the promoters and enhancers of two reporter genes are separated by 28 kb. In this case, enhancers effectively stimulate reporter gene promoters in cis and trans only in the presence of artificial Su(Hw) binding sites (SBS), in both constructs. The expression of the mutant Su(Hw) protein, which cannot interact with CP190, and the mutation inactivating Mod(mdg4)-67.2, lead to the complete loss or significant weakening of enhancer-promoter interactions, respectively. The results indicate that the new model system effectively identifies the role of individual subunits of architectural protein complexes in forming and maintaining specific long-distance interactions in the D. melanogaster model.
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Affiliation(s)
- Larisa Melnikova
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia;
| | - Varvara Molodina
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia;
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia;
| | - Anton Golovnin
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia;
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4
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Zhimulev I, Vatolina T, Levitsky V, Tsukanov A. Developmental and Housekeeping Genes: Two Types of Genetic Organization in the Drosophila Genome. Int J Mol Sci 2024; 25:4068. [PMID: 38612878 PMCID: PMC11012173 DOI: 10.3390/ijms25074068] [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: 12/29/2023] [Revised: 04/01/2024] [Accepted: 04/02/2024] [Indexed: 04/14/2024] Open
Abstract
We developed a procedure for locating genes on Drosophila melanogaster polytene chromosomes and described three types of chromosome structures (gray bands, black bands, and interbands), which differed markedly in morphological and genetic properties. This was reached through the use of our original methods of molecular and genetic analysis, electron microscopy, and bioinformatics data processing. Analysis of the genome-wide distribution of these properties led us to a bioinformatics model of the Drosophila genome organization, in which the genome was divided into two groups of genes. One was constituted by 65, in which the genome was divided into two groups, 62 genes that are expressed in most cell types during life cycle and perform basic cellular functions (the so-called "housekeeping genes"). The other one was made up of 3162 genes that are expressed only at particular stages of development ("developmental genes"). These two groups of genes are so different that we may state that the genome has two types of genetic organization. Different are the timings of their expression, chromatin packaging levels, the composition of activating and deactivating proteins, the sizes of these genes, the lengths of their introns, the organization of the promoter regions of the genes, the locations of origin recognition complexes (ORCs), and DNA replication timings.
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Affiliation(s)
- Igor Zhimulev
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Science, 630090 Novosibirsk, Russia;
| | - Tatyana Vatolina
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Science, 630090 Novosibirsk, Russia;
| | - Victor Levitsky
- Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Science, 630090 Novosibirsk, Russia; (V.L.); (A.T.)
| | - Anton Tsukanov
- Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Science, 630090 Novosibirsk, Russia; (V.L.); (A.T.)
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5
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Golovnin A, Melnikova L, Babosha V, Pokholkova GV, Slovohotov I, Umnova A, Maksimenko O, Zhimulev IF, Georgiev P. The N-Terminal Part of Drosophila CP190 Is a Platform for Interaction with Multiple Architectural Proteins. Int J Mol Sci 2023; 24:15917. [PMID: 37958900 PMCID: PMC10648081 DOI: 10.3390/ijms242115917] [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: 10/04/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/15/2023] Open
Abstract
CP190 is a co-factor in many Drosophila architectural proteins, being involved in the formation of active promoters and insulators. CP190 contains the N-terminal BTB/POZ (Broad-Complex, Tramtrack and Bric a brac/POxvirus and Zinc finger) domain and adjacent conserved regions involved in protein interactions. Here, we examined the functional roles of these domains of CP190 in vivo. The best-characterized architectural proteins with insulator functions, Pita, Su(Hw), and dCTCF, interacted predominantly with the BTB domain of CP190. Due to the difficulty of mutating the BTB domain, we obtained a transgenic line expressing a chimeric CP190 with the BTB domain of the human protein Kaiso. Another group of architectural proteins, M1BP, Opbp, and ZIPIC, interacted with one or both of the highly conserved regions in the N-terminal part of CP190. Transgenic lines of D. melanogaster expressing CP190 mutants with a deletion of each of these domains were obtained. The results showed that these mutant proteins only partially compensated for the functions of CP190, weakly binding to selective chromatin sites. Further analysis confirmed the essential role of these domains in recruitment to regulatory regions associated with architectural proteins. We also found that the N-terminal of CP190 was sufficient for recruiting Z4 and Chromator proteins and successfully achieving chromatin opening. Taken together, our results and the results of previous studies showed that the N-terminal region of CP190 is a platform for simultaneous interaction with various DNA-binding architectural proteins and transcription complexes.
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Affiliation(s)
- Anton Golovnin
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Larisa Melnikova
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Valentin Babosha
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Galina V. Pokholkova
- Laboratory of Molecular Cytogenetics, Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Science, Novosibirsk 630090, Russia (I.F.Z.)
| | - Ivan Slovohotov
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Anastasia Umnova
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Oksana Maksimenko
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
| | - Igor F. Zhimulev
- Laboratory of Molecular Cytogenetics, Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Science, Novosibirsk 630090, Russia (I.F.Z.)
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov Street, Moscow 119334, Russia
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6
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Messina O, Raynal F, Gurgo J, Fiche JB, Pancaldi V, Nollmann M. 3D chromatin interactions involving Drosophila insulators are infrequent but preferential and arise before TADs and transcription. Nat Commun 2023; 14:6678. [PMID: 37865700 PMCID: PMC10590426 DOI: 10.1038/s41467-023-42485-y] [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: 12/07/2022] [Accepted: 10/12/2023] [Indexed: 10/23/2023] Open
Abstract
In mammals, insulators contribute to the regulation of loop extrusion to organize chromatin into topologically associating domains. In Drosophila the role of insulators in 3D genome organization is, however, under current debate. Here, we addressed this question by combining bioinformatics analysis and multiplexed chromatin imaging. We describe a class of Drosophila insulators enriched at regions forming preferential chromatin interactions genome-wide. Notably, most of these 3D interactions do not involve TAD borders. Multiplexed imaging shows that these interactions occur infrequently, and only rarely involve multiple genomic regions coalescing together in space in single cells. Finally, we show that non-border preferential 3D interactions enriched in this class of insulators are present before TADs and transcription during Drosophila development. Our results are inconsistent with insulators forming stable hubs in single cells, and instead suggest that they fine-tune existing 3D chromatin interactions, providing an additional regulatory layer for transcriptional regulation.
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Affiliation(s)
- Olivier Messina
- Centre de Biologie Structurale, Univ Montpellier, CNRS UMR 5048, INSERM U1054, 34090, Montpellier, France
| | - Flavien Raynal
- CRCT, Université de Toulouse, Inserm, CNRS, Université Toulouse III-Paul Sabatier, Centre de Recherches en Cancérologie de Toulouse, Toulouse, France
| | - Julian Gurgo
- Centre de Biologie Structurale, Univ Montpellier, CNRS UMR 5048, INSERM U1054, 34090, Montpellier, France
| | - Jean-Bernard Fiche
- Centre de Biologie Structurale, Univ Montpellier, CNRS UMR 5048, INSERM U1054, 34090, Montpellier, France
| | - Vera Pancaldi
- CRCT, Université de Toulouse, Inserm, CNRS, Université Toulouse III-Paul Sabatier, Centre de Recherches en Cancérologie de Toulouse, Toulouse, France.
- Barcelona Supercomputing Center, Barcelona, Spain.
| | - Marcelo Nollmann
- Centre de Biologie Structurale, Univ Montpellier, CNRS UMR 5048, INSERM U1054, 34090, Montpellier, France.
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7
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Cavalheiro GR, Girardot C, Viales RR, Pollex T, Cao TBN, Lacour P, Feng S, Rabinowitz A, Furlong EEM. CTCF, BEAF-32, and CP190 are not required for the establishment of TADs in early Drosophila embryos but have locus-specific roles. SCIENCE ADVANCES 2023; 9:eade1085. [PMID: 36735786 PMCID: PMC9897672 DOI: 10.1126/sciadv.ade1085] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 01/03/2023] [Indexed: 05/31/2023]
Abstract
The boundaries of topologically associating domains (TADs) are delimited by insulators and/or active promoters; however, how they are initially established during embryogenesis remains unclear. Here, we examined this during the first hours of Drosophila embryogenesis. DNA-FISH confirms that intra-TAD pairwise proximity is established during zygotic genome activation (ZGA) but with extensive cell-to-cell heterogeneity. Most newly formed boundaries are occupied by combinations of CTCF, BEAF-32, and/or CP190. Depleting each insulator individually from chromatin revealed that TADs can still establish, although with lower insulation, with a subset of boundaries (~10%) being more dependent on specific insulators. Some weakened boundaries have aberrant gene expression due to unconstrained enhancer activity. However, the majority of misexpressed genes have no obvious direct relationship to changes in domain-boundary insulation. Deletion of an active promoter (thereby blocking transcription) at one boundary had a greater impact than deleting the insulator-bound region itself. This suggests that cross-talk between insulators and active promoters and/or transcription might reinforce domain boundary insulation during embryogenesis.
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Affiliation(s)
- Gabriel R. Cavalheiro
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, D-69117 Heidelberg, Baden-Württemberg, Germany
- Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences, Baden-Württemberg, Germany
| | - Charles Girardot
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, D-69117 Heidelberg, Baden-Württemberg, Germany
| | - Rebecca R. Viales
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, D-69117 Heidelberg, Baden-Württemberg, Germany
| | - Tim Pollex
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, D-69117 Heidelberg, Baden-Württemberg, Germany
| | - T. B. Ngoc Cao
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, D-69117 Heidelberg, Baden-Württemberg, Germany
| | - Perrine Lacour
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, D-69117 Heidelberg, Baden-Württemberg, Germany
- École Normale Supérieure, 45 rue d’Ulm, 75005 Paris, France
| | - Songjie Feng
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, D-69117 Heidelberg, Baden-Württemberg, Germany
| | - Adam Rabinowitz
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, D-69117 Heidelberg, Baden-Württemberg, Germany
| | - Eileen E. M. Furlong
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, D-69117 Heidelberg, Baden-Württemberg, Germany
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8
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Kahn TG, Savitsky M, Kuong C, Jacquier C, Cavalli G, Chang JM, Schwartz YB. Topological screen identifies hundreds of Cp190- and CTCF-dependent Drosophila chromatin insulator elements. SCIENCE ADVANCES 2023; 9:eade0090. [PMID: 36735780 PMCID: PMC9897668 DOI: 10.1126/sciadv.ade0090] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 01/03/2023] [Indexed: 06/18/2023]
Abstract
Drosophila insulators were the first DNA elements found to regulate gene expression by delimiting chromatin contacts. We still do not know how many of them exist and what impact they have on the Drosophila genome folding. Contrary to vertebrates, there is no evidence that fly insulators block cohesin-mediated chromatin loop extrusion. Therefore, their mechanism of action remains uncertain. To bridge these gaps, we mapped chromatin contacts in Drosophila cells lacking the key insulator proteins CTCF and Cp190. With this approach, we found hundreds of insulator elements. Their study indicates that Drosophila insulators play a minor role in the overall genome folding but affect chromatin contacts locally at many loci. Our observations argue that Cp190 promotes cobinding of other insulator proteins and that the model, where Drosophila insulators block chromatin contacts by forming loops, needs revision. Our insulator catalog provides an important resource to study mechanisms of genome folding.
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Affiliation(s)
- Tatyana G. Kahn
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | | | - Chikuan Kuong
- Department of Computer Science, National Chengchi University, Taipei City, Taiwan
| | | | - Giacomo Cavalli
- Institute of Human Genetics, UMR9002 CNRS, Montpellier, France
| | - Jia-Ming Chang
- Department of Computer Science, National Chengchi University, Taipei City, Taiwan
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9
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Soujanya M, Bihani A, Hajirnis N, Pathak RU, Mishra RK. Nuclear architecture and the structural basis of mitotic memory. CHROMOSOME RESEARCH : AN INTERNATIONAL JOURNAL ON THE MOLECULAR, SUPRAMOLECULAR AND EVOLUTIONARY ASPECTS OF CHROMOSOME BIOLOGY 2023; 31:8. [PMID: 36725757 DOI: 10.1007/s10577-023-09714-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/13/2022] [Accepted: 12/19/2022] [Indexed: 02/03/2023]
Abstract
The nucleus is a complex organelle that hosts the genome and is essential for vital processes like DNA replication, DNA repair, transcription, and splicing. The genome is non-randomly organized in the three-dimensional space of the nucleus. This functional sub-compartmentalization was thought to be organized on the framework of nuclear matrix (NuMat), a non-chromatin scaffold that functions as a substratum for various molecular processes of the nucleus. More recently, nuclear bodies or membrane-less subcompartments of the nucleus are thought to arise due to phase separation of chromatin, RNA, and proteins. The nuclear architecture is an amalgamation of the relative organization of chromatin, epigenetic landscape, the nuclear bodies, and the nucleoskeleton in the three-dimensional space of the nucleus. During mitosis, the nucleus undergoes drastic changes in morphology to the degree that it ceases to exist as such; various nuclear components, including the envelope that defines the nucleus, disintegrate, and the chromatin acquires mitosis-specific epigenetic marks and condenses to form chromosome. Upon mitotic exit, chromosomes are decondensed, re-establish hierarchical genome organization, and regain epigenetic and transcriptional status similar to that of the mother cell. How this mitotic memory is inherited during cell division remains a puzzle. NuMat components that are a part of the mitotic chromosome in the form of mitotic chromosome scaffold (MiCS) could potentially be the seeds that guide the relative re-establishment of the epigenome, chromosome territories, and the nuclear bodies. Here, we synthesize the advances towards understanding cellular memory of nuclear architecture across mitosis and propose a hypothesis that a subset of NuMat proteome essential for nucleation of various nuclear bodies are retained in MiCS to serve as seeds of mitotic memory, thus ensuring the daughter cells re-establish the complex status of nuclear architecture similar to that of the mother cells, thereby maintaining the pre-mitotic transcriptional status.
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Affiliation(s)
- Mamilla Soujanya
- CSIR - Centre for Cellular & Molecular Biology, Hyderabad, India
- AcSIR - Academy of Scientific and Innovative Research, Ghaziabad, India
| | - Ashish Bihani
- CSIR - Centre for Cellular & Molecular Biology, Hyderabad, India
| | - Nikhil Hajirnis
- CSIR - Centre for Cellular & Molecular Biology, Hyderabad, India
- Department of Anatomy and Neurobiology, University of Maryland, Baltimore, USA
| | - Rashmi U Pathak
- CSIR - Centre for Cellular & Molecular Biology, Hyderabad, India
| | - Rakesh K Mishra
- CSIR - Centre for Cellular & Molecular Biology, Hyderabad, India.
- AcSIR - Academy of Scientific and Innovative Research, Ghaziabad, India.
- TIGS - Tata Institute for Genetics and Society, Bangalore, India.
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10
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Mechanisms of Interaction between Enhancers and Promoters in Three Drosophila Model Systems. Int J Mol Sci 2023; 24:ijms24032855. [PMID: 36769179 PMCID: PMC9917889 DOI: 10.3390/ijms24032855] [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: 12/29/2022] [Revised: 01/26/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
In higher eukaryotes, the regulation of developmental gene expression is determined by enhancers, which are often located at a large distance from the promoters they regulate. Therefore, the architecture of chromosomes and the mechanisms that determine the functional interaction between enhancers and promoters are of decisive importance in the development of organisms. Mammals and the model animal Drosophila have homologous key architectural proteins and similar mechanisms in the organization of chromosome architecture. This review describes the current progress in understanding the mechanisms of the formation and regulation of long-range interactions between enhancers and promoters at three well-studied key regulatory loci in Drosophila.
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11
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Kyrchanova OV, Bylino OV, Georgiev PG. Mechanisms of enhancer-promoter communication and chromosomal architecture in mammals and Drosophila. Front Genet 2022; 13:1081088. [PMID: 36531247 PMCID: PMC9751008 DOI: 10.3389/fgene.2022.1081088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 11/18/2022] [Indexed: 12/03/2022] Open
Abstract
The spatial organization of chromosomes is involved in regulating the majority of intranuclear processes in higher eukaryotes, including gene expression. Drosophila was used as a model to discover many transcription factors whose homologs play a key role in regulation of gene expression in mammals. According to modern views, a cohesin complex mostly determines the architecture of mammalian chromosomes by forming chromatin loops on anchors created by the CTCF DNA-binding architectural protein. The role of the cohesin complex in chromosome architecture is poorly understood in Drosophila, and CTCF is merely one of many Drosophila architectural proteins with a proven potential to organize specific long-range interactions between regulatory elements in the genome. The review compares the mechanisms responsible for long-range interactions and chromosome architecture between mammals and Drosophila.
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12
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Herman N, Kadener S, Shifman S. The chromatin factor ROW cooperates with BEAF-32 in regulating long-range inducible genes. EMBO Rep 2022; 23:e54720. [PMID: 36245419 PMCID: PMC9724677 DOI: 10.15252/embr.202254720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 09/19/2022] [Accepted: 09/29/2022] [Indexed: 11/07/2022] Open
Abstract
Insulator proteins located at the boundaries of topological associated domains (TAD) are involved in higher-order chromatin organization and transcription regulation. However, it is still not clear how long-range contacts contribute to transcriptional regulation. Here, we show that relative-of-WOC (ROW) is essential for the long-range transcription regulation mediated by the boundary element-associated factor of 32kD (BEAF-32). We find that ROW physically interacts with heterochromatin proteins (HP1b and HP1c) and the insulator protein (BEAF-32). These proteins interact at TAD boundaries where ROW, through its AT-hook motifs, binds AT-rich sequences flanked by BEAF-32-binding sites and motifs. Knockdown of row downregulates genes that are long-range targets of BEAF-32 and bound indirectly by ROW (without binding motif). Analyses of high-throughput chromosome conformation capture (Hi-C) data reveal long-range interactions between promoters of housekeeping genes bound directly by ROW and promoters of developmental genes bound indirectly by ROW. Thus, our results show cooperation between BEAF-32 and the ROW complex, including HP1 proteins, to regulate the transcription of developmental and inducible genes through long-range interactions.
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Affiliation(s)
- Neta Herman
- Department of Genetics, The Institute of Life SciencesThe Hebrew University of JerusalemJerusalemIsrael
| | | | - Sagiv Shifman
- Department of Genetics, The Institute of Life SciencesThe Hebrew University of JerusalemJerusalemIsrael
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13
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A Tremendous Reorganization Journey for the 3D Chromatin Structure from Gametes to Embryos. Genes (Basel) 2022; 13:genes13101864. [PMID: 36292750 PMCID: PMC9602195 DOI: 10.3390/genes13101864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 10/02/2022] [Accepted: 10/12/2022] [Indexed: 11/04/2022] Open
Abstract
The 3D chromatin structure within the nucleus is important for gene expression regulation and correct developmental programs. Recently, the rapid development of low-input chromatin conformation capture technologies has made it possible to study 3D chromatin structures in gametes, zygotes and early embryos in a variety of species, including flies, vertebrates and mammals. There are distinct 3D chromatin structures within the male and female gametes. Following the fertilization of male and female gametes, fertilized eggs undergo drastic epigenetic reprogramming at multi levels, including the 3D chromatin structure, to convert the terminally differentiated gamete state into the totipotent state, which can give rise to an individual. However, to what extent the 3D chromatin structure reorganization is evolutionarily conserved and what the underlying mechanisms are for the tremendous reorganization in early embryos remain elusive. Here, we review the latest findings on the 3D chromatin structure reorganization during embryogenesis, and discuss the convergent and divergent reprogramming patterns and key molecular mechanisms for the 3D chromatin structure reorganization from gametes to embryos in different species. These findings shed light on how the 3D chromatin structure reorganization contribute to embryo development in different species. The findings also indicate the role of the 3D chromatin structure on the acquisition of totipotent developmental potential.
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14
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Nollmann M, Bennabi I, Götz M, Gregor T. The Impact of Space and Time on the Functional Output of the Genome. Cold Spring Harb Perspect Biol 2022; 14:a040378. [PMID: 34230036 PMCID: PMC8733053 DOI: 10.1101/cshperspect.a040378] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Over the past two decades, it has become clear that the multiscale spatial and temporal organization of the genome has important implications for nuclear function. This review centers on insights gained from recent advances in light microscopy on our understanding of transcription. We discuss spatial and temporal aspects that shape nuclear order and their consequences on regulatory components, focusing on genomic scales most relevant to function. The emerging picture is that spatiotemporal constraints increase the complexity in transcriptional regulation, highlighting new challenges, such as uncertainty about how information travels from molecular factors through the genome and space to generate a functional output.
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Affiliation(s)
- Marcelo Nollmann
- Centre de Biologie Structurale, CNRS UMR5048, INSERM U1054, Univ Montpellier, 34090 Montpellier, France
| | - Isma Bennabi
- Department of Stem Cell and Developmental Biology, CNRS UMR3738, Institut Pasteur, 75015 Paris, France
| | - Markus Götz
- Centre de Biologie Structurale, CNRS UMR5048, INSERM U1054, Univ Montpellier, 34090 Montpellier, France
| | - Thomas Gregor
- Department of Stem Cell and Developmental Biology, CNRS UMR3738, Institut Pasteur, 75015 Paris, France
- Joseph Henry Laboratory of Physics & Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA
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15
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Kaushal A, Dorier J, Wang B, Mohana G, Taschner M, Cousin P, Waridel P, Iseli C, Semenova A, Restrepo S, Guex N, Aiden EL, Gambetta MC. Essential role of Cp190 in physical and regulatory boundary formation. SCIENCE ADVANCES 2022; 8:eabl8834. [PMID: 35559678 PMCID: PMC9106302 DOI: 10.1126/sciadv.abl8834] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 04/01/2022] [Indexed: 05/31/2023]
Abstract
Boundaries in animal genomes delimit contact domains with enhanced internal contact frequencies and have debated functions in limiting regulatory cross-talk between domains and guiding enhancers to target promoters. Most mammalian boundaries form by stalling of chromosomal loop-extruding cohesin by CTCF, but most Drosophila boundaries form CTCF independently. However, how CTCF-independent boundaries form and function remains largely unexplored. Here, we assess genome folding and developmental gene expression in fly embryos lacking the ubiquitous boundary-associated factor Cp190. We find that sequence-specific DNA binding proteins such as CTCF and Su(Hw) directly interact with and recruit Cp190 to form most promoter-distal boundaries. Cp190 is essential for early development and prevents regulatory cross-talk between specific gene loci that pattern the embryo. Cp190 was, in contrast, dispensable for long-range enhancer-promoter communication at tested loci. Cp190 is thus currently the major player in fly boundary formation and function, revealing that diverse mechanisms evolved to partition genomes into independent regulatory domains.
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Affiliation(s)
- Anjali Kaushal
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Julien Dorier
- Bioinformatics Competence Center, University of Lausanne, 1015 Lausanne, Switzerland
| | - Bihan Wang
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Giriram Mohana
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Michael Taschner
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Pascal Cousin
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Patrice Waridel
- Protein Analysis Facility, University of Lausanne, 1015 Lausanne, Switzerland
| | - Christian Iseli
- Bioinformatics Competence Center, University of Lausanne, 1015 Lausanne, Switzerland
| | - Anastasiia Semenova
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Simon Restrepo
- arcoris bio AG, Lüssirainstrasse 52, 6300 Zug, Switzerland
| | - Nicolas Guex
- Bioinformatics Competence Center, University of Lausanne, 1015 Lausanne, Switzerland
| | - Erez Lieberman Aiden
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
- National Institute of Genetics, 1111 Yaya, Mishima, Shizuoka 411-8540, Japan
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA 6009, Australia
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech, Pudong 20120, China
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16
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Chathoth KT, Mikheeva LA, Crevel G, Wolfe JC, Hunter I, Beckett-Doyle S, Cotterill S, Dai H, Harrison A, Zabet NR. The role of insulators and transcription in 3D chromatin organization of flies. Genome Res 2022; 32:682-698. [PMID: 35354608 PMCID: PMC8997359 DOI: 10.1101/gr.275809.121] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 02/17/2022] [Indexed: 11/25/2022]
Abstract
The DNA in many organisms, including humans, is shown to be organized in topologically associating domains (TADs). In Drosophila, several architectural proteins are enriched at TAD borders, but it is still unclear whether these proteins play a functional role in the formation and maintenance of TADs. Here, we show that depletion of BEAF-32, Cp190, Chro, and Dref leads to changes in TAD organization and chromatin loops. Their depletion predominantly affects TAD borders located in regions moderately enriched in repressive modifications and depleted in active ones, whereas TAD borders located in euchromatin are resilient to these knockdowns. Furthermore, transcriptomic data has revealed hundreds of genes displaying differential expression in these knockdowns and showed that the majority of differentially expressed genes are located within reorganized TADs. Our work identifies a novel and functional role for architectural proteins at TAD borders in Drosophila and a link between TAD reorganization and subsequent changes in gene expression.
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Affiliation(s)
- Keerthi T Chathoth
- School of Life Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Liudmila A Mikheeva
- School of Life Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom.,Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, United Kingdom.,Department of Mathematical Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Gilles Crevel
- Department Basic Medical Sciences, St. Georges University London, London SW17 0RE, United Kingdom
| | - Jareth C Wolfe
- School of Life Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom.,Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, United Kingdom.,School of Computer Science and Electronic Engineering, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Ioni Hunter
- School of Life Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Saskia Beckett-Doyle
- School of Life Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Sue Cotterill
- Department Basic Medical Sciences, St. Georges University London, London SW17 0RE, United Kingdom
| | - Hongsheng Dai
- Department of Mathematical Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Andrew Harrison
- Department of Mathematical Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Nicolae Radu Zabet
- School of Life Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom.,Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, United Kingdom
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17
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Zinshteyn D, Barbash DA. Stonewall prevents expression of ectopic genes in the ovary and accumulates at insulator elements in D. melanogaster. PLoS Genet 2022; 18:e1010110. [PMID: 35324887 PMCID: PMC8982855 DOI: 10.1371/journal.pgen.1010110] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 04/05/2022] [Accepted: 02/18/2022] [Indexed: 11/29/2022] Open
Abstract
Germline stem cells (GSCs) are the progenitor cells of the germline for the lifetime of an animal. In Drosophila, these cells reside in a cellular niche that is required for both their maintenance (self-renewal) and differentiation (asymmetric division resulting in a daughter cell that differs from the GSC). The stem cell—daughter cell transition is tightly regulated by a number of processes, including an array of proteins required for genome stability. The germline stem-cell maintenance factor Stonewall (Stwl) associates with heterochromatin, but its molecular function is poorly understood. We performed RNA-Seq on stwl mutant ovaries and found significant derepression of many transposon families but not heterochromatic genes. We also discovered inappropriate expression of multiple classes of genes. Most prominent are testis-enriched genes, including the male germline sex-determination switch Phf7, the differentiation factor bgcn, and a large testis-specific gene cluster on chromosome 2, all of which are upregulated or ectopically expressed in stwl mutant ovaries. Surprisingly, we also found that RNAi knockdown of stwl in somatic S2 cells results in ectopic expression of these testis genes. Using parallel ChIP-Seq and RNA-Seq experiments in S2 cells, we discovered that Stwl localizes upstream of transcription start sites and at heterochromatic sequences including repetitive sequences associated with telomeres. Stwl is also enriched at bgcn, suggesting that it directly regulates this essential differentiation factor. Finally, we identify Stwl binding motifs that are shared with known insulator binding proteins. We propose that Stwl affects gene regulation, including repression of male transcripts in the female germline, by binding insulators and establishing chromatin boundaries. Stem cells are defined by their ability to divide asymmetrically, resulting in a differentiated cell and a stem cell daughter. In fruit flies, sperm and egg production begins with germline stem cells (GSCs). The ability of a GSC to differentiate or self-renew is tightly regulated by a myriad of factors. Some of these are transcription factors, which are responsible for activating or suppressing other genes to promote one state in favor of another. Stonewall is an ovarian nuclear protein required for GSC self-renewal, whose molecular function is poorly understood. Here we show that Stonewall is responsible for preventing the activation of “male” molecular programming in the fruit fly ovary. When Stonewall is absent from the ovary, egg production is terminated and testis-specific genes become highly expressed, including the male transcript of Phf7, which induces male sexual identity in female germ cells. We also show that Stonewall is likely localizing to genomic insulators, which are regions of the genome that shield genes from nearby regulators. Our findings suggest that Stonewall helps to organize the genome in ovarian germ cells and prevent expression of male genes.
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Affiliation(s)
- Daniel Zinshteyn
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Daniel A. Barbash
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
- * E-mail:
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18
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Galouzis CC, Furlong EEM. Regulating specificity in enhancer-promoter communication. Curr Opin Cell Biol 2022; 75:102065. [PMID: 35240372 DOI: 10.1016/j.ceb.2022.01.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/23/2022] [Accepted: 01/25/2022] [Indexed: 12/14/2022]
Abstract
Enhancers are cis-regulatory elements that can activate transcription remotely to regulate a specific pattern of a gene's expression. Genes typically have many enhancers that are often intermingled in the loci of other genes. To regulate expression, enhancers must therefore activate their correct promoter while ignoring others that may be in closer linear proximity. In this review, we discuss mechanisms by which enhancers engage with promoters, including recent findings on the role of cohesin and the Mediator complex, and how this specificity in enhancer-promoter communication is encoded. Genetic dissection of model loci, in addition to more recent findings using genome-wide approaches, highlight the core promoter sequence, its accessibility, cofactor-promoter preference, in addition to the surrounding genomic context, as key components.
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Affiliation(s)
| | - Eileen E M Furlong
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, D-69117, Heidelberg, Germany.
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19
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Wu H, Zhang P, Ai Z, Wei L, Zhang H, Yang F, Cui L. StackTADB: a stacking-based ensemble learning model for predicting the boundaries of topologically associating domains (TADs) accurately in fruit flies. Brief Bioinform 2022; 23:6531900. [PMID: 35181793 DOI: 10.1093/bib/bbac023] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/29/2021] [Accepted: 01/17/2022] [Indexed: 11/13/2022] Open
Abstract
Chromosome is composed of many distinct chromatin domains, referred to variably as topological domains or topologically associating domains (TADs). The domains are stable across different cell types and highly conserved across species, thus these chromatin domains have been considered as the basic units of chromosome folding and regarded as an important secondary structure in chromosome organization. However, the identification of TAD boundaries is still a great challenge due to the high cost and low resolution of Hi-C data or experiments. In this study, we propose a novel ensemble learning framework, termed as StackTADB, for predicting the boundaries of TADs. StackTADB integrates four base classifiers including Random Forest, Logistic Regression, K-NearestNeighbor and Support Vector Machine. From the analysis of a series of examinations on the data set in the previous study, it is concluded that StackTADB has optimal performance in six metrics, AUC, Accuracy, MCC, Precision, Recall and F1 score, and it is superior to the existing methods. In addition, the comparison of the performance of multiple features shows that Kmers-based features play an essential role in predicting TADs boundaries of fruit flies, and we also apply the SHapley Additive exPlanations (SHAP) framework to interpret the predictions of StackTADB to identify the reason why Kmers-based features are vital. The experimental results show that the subsequences matching the BEAF-32 motif play a crucial role in predicting the boundaries of TADs. The source code is freely available at https://github.com/HaoWuLab-Bioinformatics/StackTADB and the webserver of StackTADB is freely available at http://hwtad.sdu.edu.cn:8002/StackTADB.
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Affiliation(s)
- Hao Wu
- College of Information Engineering, Northwest A&F University, Yangling, 712100, Shaanxi, China.,School of Software, Shandong University, Jinan, 250101, Shandong, China
| | - Pengyu Zhang
- College of Information Engineering, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Zhaoheng Ai
- College of Information Engineering, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Leyi Wei
- School of Software, Shandong University, Jinan, 250101, Shandong, China
| | - Hongming Zhang
- College of Information Engineering, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Fan Yang
- Department of Biostatistics, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, 250100, Shandong, China.,Institute for Medical Dataology, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, 250100, Shandong, China
| | - Lizhen Cui
- School of Software, Shandong University, Jinan, 250101, Shandong, China
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20
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Mechanisms of CP190 Interaction with Architectural Proteins in Drosophila Melanogaster. Int J Mol Sci 2021; 22:ijms222212400. [PMID: 34830280 PMCID: PMC8618245 DOI: 10.3390/ijms222212400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/12/2021] [Accepted: 11/15/2021] [Indexed: 01/08/2023] Open
Abstract
Most of the known Drosophila architectural proteins interact with an important cofactor, CP190, that contains three domains (BTB, M, and D) that are involved in protein–protein interactions. The highly conserved N-terminal CP190 BTB domain forms a stable homodimer that interacts with unstructured regions in the three best-characterized architectural proteins: dCTCF, Su(Hw), and Pita. Here, we identified two new CP190 partners, CG4730 and CG31365, that interact with the BTB domain. The CP190 BTB resembles the previously characterized human BCL6 BTB domain, which uses its hydrophobic groove to specifically associate with unstructured regions of several transcriptional repressors. Using GST pull-down and yeast two-hybrid assays, we demonstrated that mutations in the hydrophobic groove strongly affect the affinity of CP190 BTB for the architectural proteins. In the yeast two-hybrid assay, we found that architectural proteins use various mechanisms to improve the efficiency of interaction with CP190. Pita and Su(Hw) have two unstructured regions that appear to simultaneously interact with hydrophobic grooves in the BTB dimer. In dCTCF and CG31365, two adjacent regions interact simultaneously with the hydrophobic groove of the BTB and the M domain of CP190. Finally, CG4730 interacts with the BTB, M, and D domains of CP190 simultaneously. These results suggest that architectural proteins use different mechanisms to increase the efficiency of interaction with CP190.
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21
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Wolfe JC, Mikheeva LA, Hagras H, Zabet NR. An explainable artificial intelligence approach for decoding the enhancer histone modifications code and identification of novel enhancers in Drosophila. Genome Biol 2021; 22:308. [PMID: 34749786 PMCID: PMC8574042 DOI: 10.1186/s13059-021-02532-7] [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: 10/30/2020] [Accepted: 10/29/2021] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Enhancers are non-coding regions of the genome that control the activity of target genes. Recent efforts to identify active enhancers experimentally and in silico have proven effective. While these tools can predict the locations of enhancers with a high degree of accuracy, the mechanisms underpinning the activity of enhancers are often unclear. RESULTS Using machine learning (ML) and a rule-based explainable artificial intelligence (XAI) model, we demonstrate that we can predict the location of known enhancers in Drosophila with a high degree of accuracy. Most importantly, we use the rules of the XAI model to provide insight into the underlying combinatorial histone modifications code of enhancers. In addition, we identified a large set of putative enhancers that display the same epigenetic signature as enhancers identified experimentally. These putative enhancers are enriched in nascent transcription, divergent transcription and have 3D contacts with promoters of transcribed genes. However, they display only intermediary enrichment of mediator and cohesin complexes compared to previously characterised active enhancers. We also found that 10-15% of the predicted enhancers display similar characteristics to super enhancers observed in other species. CONCLUSIONS Here, we applied an explainable AI model to predict enhancers with high accuracy. Most importantly, we identified that different combinations of epigenetic marks characterise different groups of enhancers. Finally, we discovered a large set of putative enhancers which display similar characteristics with previously characterised active enhancers.
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Affiliation(s)
- Jareth C Wolfe
- School of Life Sciences, University of Essex, Colchester, CO4 3SQ, UK
- School of Computer Science and Electronic Engineering, University of Essex, Colchester, CO4 3SQ, UK
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, E1 2AT, London, UK
| | - Liudmila A Mikheeva
- School of Life Sciences, University of Essex, Colchester, CO4 3SQ, UK
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, E1 2AT, London, UK
- Department of Mathematical Sciences, University of Essex, Colchester, CO4 3SQ, UK
| | - Hani Hagras
- School of Computer Science and Electronic Engineering, University of Essex, Colchester, CO4 3SQ, UK.
| | - Nicolae Radu Zabet
- School of Life Sciences, University of Essex, Colchester, CO4 3SQ, UK.
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, E1 2AT, London, UK.
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22
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BACH1, the master regulator of oxidative stress, has a dual effect on CFTR expression. Biochem J 2021; 478:3741-3756. [PMID: 34605540 PMCID: PMC8589331 DOI: 10.1042/bcj20210252] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 02/07/2023]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) gene lies within a topologically associated domain (TAD) in which multiple cis-regulatory elements (CREs) and transcription factors (TFs) regulate its cell-specific expression. The CREs are recruited to the gene promoter by a looping mechanism that depends upon both architectural proteins and specific TFs. An siRNA screen to identify TFs coordinating CFTR expression in airway epithelial cells suggested an activating role for BTB domain and CNC homolog 1 (BACH1). BACH1 is a ubiquitous master regulator of the cellular response to oxidative stress. Here, we show that BACH1 may have a dual effect on CFTR expression by direct occupancy of CREs at physiological oxygen (∼8%), while indirectly modulating expression under conditions of oxidative stress. Hence BACH1, can activate or repress the same gene, to fine tune expression in response to environmental cues such as cell stress. Furthermore, our 4C-seq data suggest that BACH1 can also directly regulate CFTR gene expression by modulating locus architecture through occupancy at known enhancers and structural elements, and depletion of BACH1 alters the higher order chromatin structure.
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23
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Verma S, Pathak RU, Mishra RK. Genomic organization of the autonomous regulatory domain of eyeless locus in Drosophila melanogaster. G3-GENES GENOMES GENETICS 2021; 11:6375946. [PMID: 34570231 PMCID: PMC8664461 DOI: 10.1093/g3journal/jkab338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 09/09/2021] [Indexed: 11/29/2022]
Abstract
In Drosophila, expression of eyeless (ey) gene is restricted to the developing eyes and central nervous system. However, the flanking genes, myoglianin (myo), and bent (bt) have different temporal and spatial expression patterns as compared to the ey. How distinct regulation of ey is maintained is mostly unknown. Earlier, we have identified a boundary element intervening myo and ey genes (ME boundary) that prevents the crosstalk between the cis-regulatory elements of myo and ey genes. In the present study, we further searched for the cis-elements that define the domain of ey and maintain its expression pattern. We identify another boundary element between ey and bt, the EB boundary. The EB boundary separates the regulatory landscapes of ey and bt genes. The two boundaries, ME and EB, show a long-range interaction as well as interact with the nuclear architecture. This suggests functional autonomy of the ey locus and its insulation from differentially regulated flanking regions. We also identify a new Polycomb Response Element, the ey-PRE, within the ey domain. The expression state of the ey gene, once established during early development is likely to be maintained with the help of ey-PRE. Our study proposes a general regulatory mechanism by which a gene can be maintained in a functionally independent chromatin domain in gene-rich euchromatin.
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Affiliation(s)
- Shreekant Verma
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
| | - Rashmi U Pathak
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
| | - Rakesh K Mishra
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
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24
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Kyrchanova O, Klimenko N, Postika N, Bonchuk A, Zolotarev N, Maksimenko O, Georgiev P. Drosophila architectural protein CTCF is not essential for fly survival and is able to function independently of CP190. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2021; 1864:194733. [PMID: 34311130 DOI: 10.1016/j.bbagrm.2021.194733] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/15/2021] [Accepted: 07/15/2021] [Indexed: 12/20/2022]
Abstract
CTCF is the most likely ancestor of proteins that contain large clusters of C2H2 zinc finger domains (C2H2) and is conserved among most bilateral organisms. In mammals, CTCF functions as the main architectural protein involved in the organization of topology-associated domains (TADs). In vertebrates and Drosophila, CTCF is involved in the regulation of homeotic genes. Previously, it was found that null mutations in the dCTCF gene died as pharate adults, which failed to eclose from their pupal case, or shortly after hatching of adults. Here, we obtained several new null dCTCF mutations and found that the complete inactivation of dCTCF appears is limited mainly to phenotypic manifestations of the Abd-B gene and fertility of adult flies. Many modifiers that are not associated with an independent phenotypic manifestation can significantly enhance the expressivity of the null dCTCF mutations, indicating that other architectural proteins are able to functionally compensate for dCTCF inactivation in Drosophila. We also mapped the 715-735 aa region of dCTCF as being essential for the interaction with the BTB (Broad-Complex, Tramtrack, and Bric a brac) and microtubule-targeting (M) domains of the CP190 protein, which binds to many architectural proteins. However, the mutational analysis showed that the interaction with CP190 was not important for the functional activity of dCTCF in vivo.
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Affiliation(s)
- Olga Kyrchanova
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia; Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Natalia Klimenko
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Nikolay Postika
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Artem Bonchuk
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia; Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Nikolay Zolotarev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Oksana Maksimenko
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia.
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25
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Peterson SC, Samuelson KB, Hanlon SL. Multi-Scale Organization of the Drosophila melanogaster Genome. Genes (Basel) 2021; 12:817. [PMID: 34071789 PMCID: PMC8228293 DOI: 10.3390/genes12060817] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/21/2021] [Accepted: 05/26/2021] [Indexed: 12/16/2022] Open
Abstract
Interphase chromatin, despite its appearance, is a highly organized framework of loops and bends. Chromosomes are folded into topologically associating domains, or TADs, and each chromosome and its homolog occupy a distinct territory within the nucleus. In Drosophila, genome organization is exceptional because homologous chromosome pairing is in both germline and somatic tissues, which promote interhomolog interactions such as transvection that can affect gene expression in trans. In this review, we focus on what is known about genome organization in Drosophila and discuss it from TADs to territory. We start by examining intrachromosomal organization at the sub-chromosome level into TADs, followed by a comprehensive analysis of the known proteins that play a key role in TAD formation and boundary establishment. We then zoom out to examine interhomolog interactions such as pairing and transvection that are abundant in Drosophila but rare in other model systems. Finally, we discuss chromosome territories that form within the nucleus, resulting in a complete picture of the multi-scale organization of the Drosophila genome.
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Affiliation(s)
| | | | - Stacey L. Hanlon
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA; (S.C.P.); (K.B.S.)
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26
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Sabirov M, Kyrchanova O, Pokholkova GV, Bonchuk A, Klimenko N, Belova E, Zhimulev IF, Maksimenko O, Georgiev P. Mechanism and functional role of the interaction between CP190 and the architectural protein Pita in Drosophila melanogaster. Epigenetics Chromatin 2021; 14:16. [PMID: 33752739 PMCID: PMC7983404 DOI: 10.1186/s13072-021-00391-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 03/08/2021] [Indexed: 12/16/2022] Open
Abstract
Background Pita is required for Drosophila development and binds specifically to a long motif in active promoters and insulators. Pita belongs to the Drosophila family of zinc-finger architectural proteins, which also includes Su(Hw) and the conserved among higher eukaryotes CTCF. The architectural proteins maintain the active state of regulatory elements and the long-distance interactions between them. In particular, Pita is involved in the formation of several boundaries between regulatory domains that controlled the expression of three hox genes in the Bithorax complex (BX-C). The CP190 protein is recruited to chromatin through interaction with the architectural proteins. Results Using in vitro pull-down analysis, we precisely mapped two unstructured regions of Pita that interact with the BTB domain of CP190. Then we constructed transgenic lines expressing the Pita protein of the wild-type and mutant variants lacking CP190-interacting regions. We have demonstrated that CP190-interacting region of the Pita can maintain nucleosome-free open chromatin and is critical for Pita-mediated enhancer blocking activity in BX-C. At the same time, interaction with CP190 is not required for the in vivo function of the mutant Pita protein, which binds to the same regions of the genome as the wild-type protein. Unexpectedly, we found that CP190 was still associated with the most of genome regions bound by the mutant Pita protein, which suggested that other architectural proteins were continuing to recruit CP190 to these regions. Conclusions The results directly demonstrate role of CP190 in insulation and support a model in which the regulatory elements are composed of combinations of binding sites that interact with several architectural proteins with similar functions. Supplementary Information The online version contains supplementary material available at 10.1186/s13072-021-00391-x.
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Affiliation(s)
- Marat Sabirov
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 3 4/5 Vavilov St., Moscow, 119334, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334, Russia
| | - Olga Kyrchanova
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 3 4/5 Vavilov St., Moscow, 119334, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334, Russia
| | - Galina V Pokholkova
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences (IMCB RAS), Novosibirsk, Russia
| | - Artem Bonchuk
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 3 4/5 Vavilov St., Moscow, 119334, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334, Russia
| | - Natalia Klimenko
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334, Russia
| | - Elena Belova
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 3 4/5 Vavilov St., Moscow, 119334, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334, Russia
| | - Igor F Zhimulev
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences (IMCB RAS), Novosibirsk, Russia
| | - Oksana Maksimenko
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow, 119334, Russia.
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 3 4/5 Vavilov St., Moscow, 119334, Russia.
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27
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Kyrchanova O, Georgiev P. Mechanisms of Enhancer-Promoter Interactions in Higher Eukaryotes. Int J Mol Sci 2021; 22:ijms22020671. [PMID: 33445415 PMCID: PMC7828040 DOI: 10.3390/ijms22020671] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 12/28/2020] [Accepted: 01/09/2021] [Indexed: 12/13/2022] Open
Abstract
In higher eukaryotes, enhancers determine the activation of developmental gene transcription in specific cell types and stages of embryogenesis. Enhancers transform the signals produced by various transcription factors within a given cell, activating the transcription of the targeted genes. Often, developmental genes can be associated with dozens of enhancers, some of which are located at large distances from the promoters that they regulate. Currently, the mechanisms underlying specific distance interactions between enhancers and promoters remain poorly understood. This review briefly describes the properties of enhancers and discusses the mechanisms of distance interactions and potential proteins involved in this process.
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28
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Sun Q, Perez-Rathke A, Czajkowsky DM, Shao Z, Liang J. High-resolution single-cell 3D-models of chromatin ensembles during Drosophila embryogenesis. Nat Commun 2021; 12:205. [PMID: 33420075 PMCID: PMC7794469 DOI: 10.1038/s41467-020-20490-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/02/2020] [Indexed: 01/29/2023] Open
Abstract
Single-cell chromatin studies provide insights into how chromatin structure relates to functions of individual cells. However, balancing high-resolution and genome wide-coverage remains challenging. We describe a computational method for the reconstruction of large 3D-ensembles of single-cell (sc) chromatin conformations from population Hi-C that we apply to study embryogenesis in Drosophila. With minimal assumptions of physical properties and without adjustable parameters, our method generates large ensembles of chromatin conformations via deep-sampling. Our method identifies specific interactions, which constitute 5-6% of Hi-C frequencies, but surprisingly are sufficient to drive chromatin folding, giving rise to the observed Hi-C patterns. Modeled sc-chromatins quantify chromatin heterogeneity, revealing significant changes during embryogenesis. Furthermore, >50% of modeled sc-chromatin maintain topologically associating domains (TADs) in early embryos, when no population TADs are perceptible. Domain boundaries become fixated during development, with strong preference at binding-sites of insulator-complexes upon the midblastula transition. Overall, high-resolution 3D-ensembles of sc-chromatin conformations enable further in-depth interpretation of population Hi-C, improving understanding of the structure-function relationship of genome organization.
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Affiliation(s)
- Qiu Sun
- Shanghai Center for System Biomedicine, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Alan Perez-Rathke
- Department of Bioengineering, University of Illinois at Chicago, SEO, MC-063, Chicago, IL, 60607-7052, USA
| | - Daniel M Czajkowsky
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Zhifeng Shao
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Jie Liang
- Department of Bioengineering, University of Illinois at Chicago, SEO, MC-063, Chicago, IL, 60607-7052, USA.
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29
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Martin PC, Zabet NR. Dissecting the binding mechanisms of transcription factors to DNA using a statistical thermodynamics framework. Comput Struct Biotechnol J 2020; 18:3590-3605. [PMID: 33304457 PMCID: PMC7708957 DOI: 10.1016/j.csbj.2020.11.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 01/22/2023] Open
Abstract
Transcription Factors (TFs) bind to DNA and control activity of target genes. Here, we present ChIPanalyser, a user-friendly, versatile and powerful R/Bioconductor package predicting and modelling the binding of TFs to DNA. ChIPanalyser performs similarly to state-of-the-art tools, but is an explainable model and provides biological insights into binding mechanisms of TFs. We focused on investigating the binding mechanisms of three TFs that are known architectural proteins CTCF, BEAF-32 and su(Hw) in three Drosophila cell lines (BG3, Kc167 and S2). While CTCF preferentially binds only to a subset of high affinity sites located mainly in open chromatin, BEAF-32 binds to most of its high affinity binding sites available in open chromatin. In contrast, su(Hw) binds to both open chromatin and also partially closed chromatin. Most importantly, differences in TF binding profiles between cell lines for these TFs are mainly driven by differences in DNA accessibility and not by differences in TF concentrations between cell lines. Finally, we investigated binding of Hox TFs in Drosophila and found that Ubx binds only in open chromatin, while Abd-B and Dfd are capable to bind in both open and partially closed chromatin. Overall, our results show that TFs display different binding mechanisms and that our model is able to recapitulate their specific binding behaviour.
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Affiliation(s)
- Patrick C.N. Martin
- School of Life Sciences, University of Essex, Colchester CO4 3SQ, UK
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Nicolae Radu Zabet
- School of Life Sciences, University of Essex, Colchester CO4 3SQ, UK
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK
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30
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Magaña-Acosta M, Valadez-Graham V. Chromatin Remodelers in the 3D Nuclear Compartment. Front Genet 2020; 11:600615. [PMID: 33329746 PMCID: PMC7673392 DOI: 10.3389/fgene.2020.600615] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 10/07/2020] [Indexed: 12/15/2022] Open
Abstract
Chromatin remodeling complexes (CRCs) use ATP hydrolysis to maintain correct expression profiles, chromatin stability, and inherited epigenetic states. More than 20 CRCs have been described to date, which encompass four large families defined by their ATPase subunits. These complexes and their subunits are conserved from yeast to humans through evolution. Their activities depend on their catalytic subunits which through ATP hydrolysis provide the energy necessary to fulfill cellular functions such as gene transcription, DNA repair, and transposon silencing. These activities take place at the first levels of chromatin compaction, and CRCs have been recognized as essential elements of chromatin dynamics. Recent studies have demonstrated an important role for these complexes in the maintenance of higher order chromatin structure. In this review, we present an overview of the organization of the genome within the cell nucleus, the different levels of chromatin compaction, and importance of the architectural proteins, and discuss the role of CRCs and how their functions contribute to the dynamics of the 3D genome organization.
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Affiliation(s)
- Mauro Magaña-Acosta
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Viviana Valadez-Graham
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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31
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Melnikova LS, Georgiev PG, Golovnin AK. The Functions and Mechanisms of Action of Insulators in the Genomes of Higher Eukaryotes. Acta Naturae 2020; 12:15-33. [PMID: 33456975 PMCID: PMC7800606 DOI: 10.32607/actanaturae.11144] [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: 08/07/2020] [Accepted: 10/12/2020] [Indexed: 12/22/2022] Open
Abstract
The mechanisms underlying long-range interactions between chromatin regions and the principles of chromosomal architecture formation are currently under extensive scrutiny. A special class of regulatory elements known as insulators is believed to be involved in the regulation of specific long-range interactions between enhancers and promoters. This review focuses on the insulators of Drosophila and mammals, and it also briefly characterizes the proteins responsible for their functional activity. It was initially believed that the main properties of insulators are blocking of enhancers and the formation of independent transcription domains. We present experimental data proving that the chromatin loops formed by insulators play only an auxiliary role in enhancer blocking. The review also discusses the mechanisms involved in the formation of topologically associating domains and their role in the formation of the chromosomal architecture and regulation of gene transcription.
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Affiliation(s)
- L. S. Melnikova
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334 Russia
| | - P. G. Georgiev
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334 Russia
| | - A. K. Golovnin
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334 Russia
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32
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Fresán U, Rodríguez-Sánchez MA, Reina O, Corces VG, Espinàs ML. Haspin kinase modulates nuclear architecture and Polycomb-dependent gene silencing. PLoS Genet 2020; 16:e1008962. [PMID: 32750047 PMCID: PMC7428214 DOI: 10.1371/journal.pgen.1008962] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 08/14/2020] [Accepted: 06/29/2020] [Indexed: 12/14/2022] Open
Abstract
Haspin, a highly conserved kinase in eukaryotes, has been shown to be responsible for phosphorylation of histone H3 at threonine 3 (H3T3ph) during mitosis, in mammals and yeast. Here we report that haspin is the kinase that phosphorylates H3T3 in Drosophila melanogaster and it is involved in sister chromatid cohesion during mitosis. Our data reveal that haspin also phosphorylates H3T3 in interphase. H3T3ph localizes in broad silenced domains at heterochromatin and lamin-enriched euchromatic regions. Loss of haspin compromises insulator activity in enhancer-blocking assays and triggers a decrease in nuclear size that is accompanied by changes in nuclear envelope morphology. We show that haspin is a suppressor of position-effect variegation involved in heterochromatin organization. Our results also demonstrate that haspin is necessary for pairing-sensitive silencing and it is required for robust Polycomb-dependent homeotic gene silencing. Haspin associates with the cohesin complex in interphase, mediates Pds5 binding to chromatin and cooperates with Pds5-cohesin to modify Polycomb-dependent homeotic transformations. Therefore, this study uncovers an unanticipated role for haspin kinase in genome organization of interphase cells and demonstrates that haspin is required for homeotic gene regulation.
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Affiliation(s)
- Ujué Fresán
- Institut de Biologia Molecular de Barcelona, IBMB-CSIC, Barcelona, Spain
- Institute for Research in Biomedicine IRB, Barcelona, Spain
| | | | - Oscar Reina
- Bioinformatics and Biostatistics Unit, Institute for Research in Biomedicine IRB, Barcelona, Spain
| | - Victor G. Corces
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - M. Lluisa Espinàs
- Institut de Biologia Molecular de Barcelona, IBMB-CSIC, Barcelona, Spain
- Institute for Research in Biomedicine IRB, Barcelona, Spain
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33
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Dong Y, Avva SVSP, Maharjan M, Jacobi J, Hart CM. Promoter-Proximal Chromatin Domain Insulator Protein BEAF Mediates Local and Long-Range Communication with a Transcription Factor and Directly Activates a Housekeeping Promoter in Drosophila. Genetics 2020; 215:89-101. [PMID: 32179582 PMCID: PMC7198264 DOI: 10.1534/genetics.120.303144] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 03/12/2020] [Indexed: 12/23/2022] Open
Abstract
BEAF (Boundary Element-Associated Factor) was originally identified as a Drosophila melanogaster chromatin domain insulator-binding protein, suggesting a role in gene regulation through chromatin organization and dynamics. Genome-wide mapping found that BEAF usually binds near transcription start sites, often of housekeeping genes, suggesting a role in promoter function. This would be a nontraditional role for an insulator-binding protein. To gain insight into molecular mechanisms of BEAF function, we identified interacting proteins using yeast two-hybrid assays. Here, we focus on the transcription factor Serendipity δ (Sry-δ). Interactions were confirmed in pull-down experiments using bacterially expressed proteins, by bimolecular fluorescence complementation, and in a genetic assay in transgenic flies. Sry-δ interacted with promoter-proximal BEAF both when bound to DNA adjacent to BEAF or > 2-kb upstream to activate a reporter gene in transient transfection experiments. The interaction between BEAF and Sry-δ was detected using both a minimal developmental promoter (y) and a housekeeping promoter (RpS12), while BEAF alone strongly activated the housekeeping promoter. These two functions for BEAF implicate it in playing a direct role in gene regulation at hundreds of BEAF-associated promoters.
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Affiliation(s)
- Yuankai Dong
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803
| | - S V Satya Prakash Avva
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Mukesh Maharjan
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Janice Jacobi
- Hayward Genetics Center, Tulane University, New Orleans, Louisiana 70112
| | - Craig M Hart
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803
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34
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Melnikova LS, Kostyuchenko MV, Georgiev PG, Golovnin AK. The Chriz Protein Promotes the Recruitment of the Z4 Protein to the STAT-Dependent Promoters. DOKL BIOCHEM BIOPHYS 2020; 490:29-33. [PMID: 32342309 DOI: 10.1134/s1607672920010111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 10/16/2019] [Accepted: 10/16/2019] [Indexed: 11/23/2022]
Abstract
Proteins Z4/putzig and Chriz/Chromator are involved in the chromatin organization on the promoters of the majority of Drosophila genes. It was shown that the Chriz protein region from aa 273 to 503 is required for the interaction with the Z4 protein. Deletion of this sequence leads to derepression of a number of STAT-dependent genes and development of melanotic tumors in flies. The results of this study suggest that the Chriz protein promotes the recruitment of the Z4 protein to chromatin.
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Affiliation(s)
- L S Melnikova
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.
| | - M V Kostyuchenko
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - P G Georgiev
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - A K Golovnin
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
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35
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In situ dissection of domain boundaries affect genome topology and gene transcription in Drosophila. Nat Commun 2020; 11:894. [PMID: 32060283 PMCID: PMC7021724 DOI: 10.1038/s41467-020-14651-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 01/23/2020] [Indexed: 02/06/2023] Open
Abstract
Chromosomes are organized into high-frequency chromatin interaction domains called topologically associating domains (TADs), which are separated from each other by domain boundaries. The molecular mechanisms responsible for TAD formation are not yet fully understood. In Drosophila, it has been proposed that transcription is fundamental for TAD organization while the participation of genetic sequences bound by architectural proteins (APs) remains controversial. Here, we investigate the contribution of domain boundaries to TAD organization and the regulation of gene expression at the Notch gene locus in Drosophila. We find that deletion of domain boundaries results in TAD fusion and long-range topological defects that are accompanied by loss of APs and RNA Pol II chromatin binding as well as defects in transcription. Together, our results provide compelling evidence of the contribution of discrete genetic sequences bound by APs and RNA Pol II in the partition of the genome into TADs and in the regulation of gene expression in Drosophila. In Drosophila, transcription is thought to be required for TAD formation, while the role of architectural proteins remains controversial. Here, the authors find that deletion of domain boundaries at the fly Notch locus results in TAD fusion and long-range topological defects, loss of architectural protein and RNA Pol II chromatin binding, and transcription defects.
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36
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Melnikova L, Molodina V, Erokhin M, Georgiev P, Golovnin A. HIPP1 stabilizes the interaction between CP190 and Su(Hw) in the Drosophila insulator complex. Sci Rep 2019; 9:19102. [PMID: 31836797 PMCID: PMC6911044 DOI: 10.1038/s41598-019-55617-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 11/29/2019] [Indexed: 12/14/2022] Open
Abstract
Suppressor of Hairy-wing [Su(Hw)] is one of the best characterized architectural proteins in Drosophila and recruits the CP190 and Mod(mdg4)-67.2 proteins to chromatin, where they form a well-known insulator complex. Recently, HP1 and insulator partner protein 1 (HIPP1), a homolog of the human co-repressor Chromodomain Y-Like (CDYL), was identified as a new partner for Su(Hw). Here, we performed a detailed analysis of the domains involved in the HIPP1 interactions with Su(Hw)-dependent complexes. HIPP1 was found to directly interact with the Su(Hw) C-terminal region (aa 720–892) and with CP190, but not with Mod(mdg4)-67.2. We have generated Hipp1 null mutants (HippΔ1) and found that the loss of Hipp1 does not affect the enhancer-blocking or repression activities of the Su(Hw)-dependent complex. However, the simultaneous inactivation of both HIPP1 and Mod(mdg4)-67.2 proteins resulted in reduced CP190 binding with Su(Hw) sites and significantly altered gypsy insulator activity. Taken together, these results suggested that the HIPP1 protein stabilized the interaction between CP190 and the Su(Hw)-dependent complex.
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Affiliation(s)
- Larisa Melnikova
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334, Moscow, Russia
| | - Varvara Molodina
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334, Moscow, Russia
| | - Maksim Erokhin
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334, Moscow, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334, Moscow, Russia
| | - Anton Golovnin
- Department of Drosophila Molecular Genetics, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334, Moscow, Russia.
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37
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Volkova EI, Andreyenkova NG, Andreyenkov OV, Sidorenko DS, Zhimulev IF, Demakov SA. Structural and Functional Dissection of the 5' Region of the Notch Gene in Drosophila melanogaster. Genes (Basel) 2019; 10:E1037. [PMID: 31842424 PMCID: PMC6947440 DOI: 10.3390/genes10121037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 12/06/2019] [Accepted: 12/10/2019] [Indexed: 12/16/2022] Open
Abstract
Notch is a key factor of a signaling cascade which regulates cell differentiation in all multicellular organisms. Numerous investigations have been directed mainly at studying the mechanism of Notch protein action; however, very little is known about the regulation of activity of the gene itself. Here, we provide the results of targeted 5'-end editing of the Drosophila Notch gene in its native environment and genetic and cytological effects of these changes. Using the Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR associated protein 9 (CRISPR/Cas9) system in combination with homologous recombination, we obtained a founder fly stock in which a 4-kb fragment, including the 5' nontranscribed region, the first exon, and a part of the first intron of Notch, was replaced by an attachment Phage (attP) site. Then, fly lines carrying a set of six deletions within the 5'untranscribed region of the gene were obtained by ΦC31-mediated integration of transgenic constructs. Part of these deletions does not affect gene activity, but their combinations with transgenic construct in the first intron of the gene cause defects in the Notch target tissues. At the polytene chromosome level we defined a DNA segment (~250 bp) in the Notch5'-nontranscribed region which when deleted leads to disappearance of the 3C6/C7 interband and elimination of CTC-Factor (CTCF) and Chromator (CHRIZ) insulator proteins in this region.
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Affiliation(s)
- Elena I. Volkova
- Department of the Structure and Function of Chromosomes, Laboratory of Chromosome Engineering, Institute of Molecular and Cellular Biology SB RAS, 630090 Novosibirsk, Russia; (E.I.V.); (N.G.A.); (O.V.A.); (D.S.S.); (I.F.Z.)
| | - Natalya G. Andreyenkova
- Department of the Structure and Function of Chromosomes, Laboratory of Chromosome Engineering, Institute of Molecular and Cellular Biology SB RAS, 630090 Novosibirsk, Russia; (E.I.V.); (N.G.A.); (O.V.A.); (D.S.S.); (I.F.Z.)
| | - Oleg V. Andreyenkov
- Department of the Structure and Function of Chromosomes, Laboratory of Chromosome Engineering, Institute of Molecular and Cellular Biology SB RAS, 630090 Novosibirsk, Russia; (E.I.V.); (N.G.A.); (O.V.A.); (D.S.S.); (I.F.Z.)
| | - Darya S. Sidorenko
- Department of the Structure and Function of Chromosomes, Laboratory of Chromosome Engineering, Institute of Molecular and Cellular Biology SB RAS, 630090 Novosibirsk, Russia; (E.I.V.); (N.G.A.); (O.V.A.); (D.S.S.); (I.F.Z.)
| | - Igor F. Zhimulev
- Department of the Structure and Function of Chromosomes, Laboratory of Chromosome Engineering, Institute of Molecular and Cellular Biology SB RAS, 630090 Novosibirsk, Russia; (E.I.V.); (N.G.A.); (O.V.A.); (D.S.S.); (I.F.Z.)
- Structural, Functional and Comparative Genomics Laboratory, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Sergey A. Demakov
- Department of the Structure and Function of Chromosomes, Laboratory of Chromosome Engineering, Institute of Molecular and Cellular Biology SB RAS, 630090 Novosibirsk, Russia; (E.I.V.); (N.G.A.); (O.V.A.); (D.S.S.); (I.F.Z.)
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Global chromatin conformation differences in the Drosophila dosage compensated chromosome X. Nat Commun 2019; 10:5355. [PMID: 31767860 PMCID: PMC6877619 DOI: 10.1038/s41467-019-13350-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 11/01/2019] [Indexed: 01/08/2023] Open
Abstract
In Drosophila melanogaster the single male chromosome X undergoes an average twofold transcriptional upregulation for balancing the transcriptional output between sexes. Previous literature hypothesised that a global change in chromosome structure may accompany this process. However, recent studies based on Hi-C failed to detect these differences. Here we show that global conformational differences are specifically present in the male chromosome X and detectable using Hi-C data on sex-sorted embryos, as well as male and female cell lines, by leveraging custom data analysis solutions. We find the male chromosome X has more mid-/long-range interactions. We also identify differences at structural domain boundaries containing BEAF-32 in conjunction with CP190 or Chromator. Weakening of these domain boundaries in male chromosome X co-localizes with the binding of the dosage compensation complex and its co-factor CLAMP, reported to enhance chromatin accessibility. Together, our data strongly indicate that chromosome X dosage compensation affects global chromosome structure. In Drosophila, dosage compensation involves a twofold transcriptional upregulation of the single male chromosome X. Here the authors show that global conformational differences are specifically present in the male X chromosome and detectable using Hi-C data, indicating that dosage compensation affects global chromosome structure.
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Matthews NE, White R. Chromatin Architecture in the Fly: Living without CTCF/Cohesin Loop Extrusion?: Alternating Chromatin States Provide a Basis for Domain Architecture in Drosophila. Bioessays 2019; 41:e1900048. [PMID: 31264253 DOI: 10.1002/bies.201900048] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/08/2019] [Indexed: 12/15/2022]
Abstract
The organization of the genome into topologically associated domains (TADs) appears to be a fundamental process occurring across a wide range of eukaryote organisms, and it likely plays an important role in providing an architectural foundation for gene regulation. Initial studies emphasized the remarkable parallels between TAD organization in organisms as diverse as Drosophila and mammals. However, whereas CCCTC-binding factor (CTCF)/cohesin loop extrusion is emerging as a key mechanism for the formation of mammalian topological domains, the genome organization in Drosophila appears to depend primarily on the partitioning of chromatin state domains. Recent work suggesting a fundamental conserved role of chromatin state in building domain architecture is discussed and insights into genome organization from recent studies in Drosophila are considered.
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Affiliation(s)
- Nicholas E Matthews
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3DY, UK
| | - Rob White
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3DY, UK
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40
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Mourad R, Cuvier O. TAD-free analysis of architectural proteins and insulators. Nucleic Acids Res 2019; 46:e27. [PMID: 29272504 PMCID: PMC5861416 DOI: 10.1093/nar/gkx1246] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 12/05/2017] [Indexed: 11/20/2022] Open
Abstract
The three-dimensional (3D) organization of the genome is intimately related to numerous key biological functions including gene expression and DNA replication regulations. The mechanisms by which molecular drivers functionally organize the 3D genome, such as topologically associating domains (TADs), remain to be explored. Current approaches consist in assessing the enrichments or influences of proteins at TAD borders. Here, we propose a TAD-free model to directly estimate the blocking effects of architectural proteins, insulators and DNA motifs on long-range contacts, making the model intuitive and biologically meaningful. In addition, the model allows analyzing the whole Hi-C information content (2D information) instead of only focusing on TAD borders (1D information). The model outperforms multiple logistic regression at TAD borders in terms of parameter estimation accuracy and is validated by enhancer-blocking assays. In Drosophila, the results support the insulating role of simple sequence repeats and suggest that the blocking effects depend on the number of repeats. Motif analysis uncovered the roles of the transcriptional factors pannier and tramtrack in blocking long-range contacts. In human, the results suggest that the blocking effects of the well-known architectural proteins CTCF, cohesin and ZNF143 depend on the distance between loci, where each protein may participate at different scales of the 3D chromatin organization.
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Affiliation(s)
- Raphaël Mourad
- LBME, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Olivier Cuvier
- LBME, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse, France
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41
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Zykova TY, Levitsky VG, Zhimulev IF. Architecture of Promoters of House-Keeping Genes in Polytene Chromosome Interbands of Drosophila melanogaster. DOKL BIOCHEM BIOPHYS 2019; 485:95-100. [PMID: 31201623 DOI: 10.1134/s1607672919020029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Indexed: 12/22/2022]
Abstract
This is the first study to investigate the molecular-genetic organization of polytene chromosome interbands located on both molecular and cytological maps of Drosophila genome. The majority of the studied interbands contained one gene with a single transcription initiation site; the remaining interbands contained one gene with several alternative promoters, two or more unidirectional genes, and "head-to-head" arranged genes. In addition, intricately arranged interbands containing three or more genes in both unidirectional and bidirectional orientation were found. Insulator proteins, ORC, P-insertions, DNase I hypersensitive sites, and other open chromatin structures were situated in the promoter region of the genes located in the interbands. This area is critical for the formation of the interband, an open chromatin region in which gene transcription and replication are combined.
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Affiliation(s)
- T Yu Zykova
- Institute of Molecular and Cellular Biology, Siberian Branch, Russian Academy of Sciences, 630090, Novosibirsk, Russia.
| | - V G Levitsky
- Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, 630090, Novosibirsk, Russia.,Novosibirsk State University, 630090, Novosibirsk, Russia
| | - I F Zhimulev
- Institute of Molecular and Cellular Biology, Siberian Branch, Russian Academy of Sciences, 630090, Novosibirsk, Russia.,Novosibirsk State University, 630090, Novosibirsk, Russia
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42
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Piwko P, Vitsaki I, Livadaras I, Delidakis C. The Role of Insulators in Transgene Transvection in Drosophila. Genetics 2019; 212:489-508. [PMID: 30948430 PMCID: PMC6553826 DOI: 10.1534/genetics.119.302165] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 04/02/2019] [Indexed: 12/19/2022] Open
Abstract
Transvection is the phenomenon where a transcriptional enhancer activates a promoter located on the homologous chromosome. It has been amply documented in Drosophila where homologs are closely paired in most, if not all, somatic nuclei, but it has been known to rarely occur in mammals as well. We have taken advantage of site-directed transgenesis to insert reporter constructs into the same genetic locus in Drosophila and have evaluated their ability to engage in transvection by testing many heterozygous combinations. We find that transvection requires the presence of an insulator element on both homologs. Homotypic trans-interactions between four different insulators can support transvection: the gypsy insulator (GI), Wari, Fab-8 and 1A2; GI and Fab-8 are more effective than Wari or 1A2 We show that, in the presence of insulators, transvection displays the characteristics that have been previously described: it requires homolog pairing, but can happen at any of several loci in the genome; a solitary enhancer confronted with an enhancerless reporter is sufficient to drive transcription; it is weaker than the action of the same enhancer-promoter pair in cis, and it is further suppressed by cis-promoter competition. Though necessary, the presence of homotypic insulators is not sufficient for transvection; their position, number and orientation matters. A single GI adjacent to both enhancer and promoter is the optimal configuration. The identity of enhancers and promoters in the vicinity of a trans-interacting insulator pair is also important, indicative of complex insulator-enhancer-promoter interactions.
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Affiliation(s)
- Pawel Piwko
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion 70013, Crete, Greece
- Department of Biology, University of Crete, Heraklion 70013, Crete, Greece
| | - Ilektra Vitsaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion 70013, Crete, Greece
- Department of Biology, University of Crete, Heraklion 70013, Crete, Greece
| | - Ioannis Livadaras
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion 70013, Crete, Greece
| | - Christos Delidakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Heraklion 70013, Crete, Greece
- Department of Biology, University of Crete, Heraklion 70013, Crete, Greece
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Sidorenko DS, Zykova TY, Khoroshko VA, Pokholkova GV, Demakov SA, Larsson J, Belyaeva ES, Zhimulev IF. Polytene chromosomes reflect functional organization of the Drosophila genome. Vavilovskii Zhurnal Genet Selektsii 2019. [DOI: 10.18699/vj19.474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Polytene chromosomes of Drosophila melanogaster are a convenient model for studying interphase chromosomes of eukaryotes. They are giant in size in comparison with diploid cell chromosomes and have a pattern of cross stripes resulting from the ordered chromatid arrangement. Each region of polytene chromosomes has a unique banding pattern. Using the model of four chromatin types that reveals domains of varying compaction degrees, we were able to correlate the physical and cytological maps of some polytene chromosome regions and to show the main properties of genetic and molecular organization of bands and interbands, that we describe in this review. On the molecular map of the genome, the interbands correspond to decompacted aquamarine chromatin and 5’ ends of ubiquitously active genes. Gray bands contain lazurite and malachite chromatin, intermediate in the level of compaction, and, mainly, coding parts of genes. Dense black transcriptionally inactive bands are enriched in ruby chromatin. Localization of several dozens of interbands on the genome molecular map allowed us to study in detail their architecture according to the data of whole genome projects. The distribution of proteins and regulatory elements of the genome in the promoter regions of genes localized in the interbands shows that these parts of interbands are probably responsible for the formation of open chromatin that is visualized in polytene chromosomes as interbands. Thus, the permanent genetic activity of interbands and gray bands and the inactivity of genes in black bands are the basis of the universal banding pattern in the chromosomes of all Drosophila tissues. The smallest fourth chromosome of Drosophila with an atypical protein composition of chromatin is a special case. Using the model of four chromatin states and fluorescent in situ hybridization, its cytological map was refined and the genomic coordinates of all bands and interbands were determined. It was shown that, in spite of the peculiarities of this chromosome, its band organization in general corresponds to the rest of the genome. Extremely long genes of different Drosophila chromosomes do not fit the common scheme, since they can occupy a series of alternating bands and interbands (up to nine chromosomal structures) formed by parts of these genes.
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Affiliation(s)
| | | | | | | | | | - J. Larsson
- Department of Molecular Biology, Umea University
| | | | - I. F. Zhimulev
- Institute of Molecular and Cellular Biology, SB RAS; 3 Laboratory of Structural, Functional and Comparative Genomics of the Novosibirsk State University
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44
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Schwartz (Berkaeva) MB, Pankova TE, Demakov SA. ADF1 and BEAF-32 chromatin proteins affect nucleosome positioning and DNA decompaction in 61C7/C8 interband region of Drosophila melanogaster polytene chromosomes. Vavilovskii Zhurnal Genet Selektsii 2019. [DOI: 10.18699/vj19.475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The formation of interphase chromosomes is a multi-level process in which DNA is compacted several thousandfold by association with histones and non-histone proteins. The first step of compaction includes the formation of nucleosomes – the basic repeating units of chromatin. Further packaging occurs due to DNA binding to histone H1 and non-histone proteins involved in enhancer-promoter and insulator interactions. Under these conditions, the genome retains its functionality due to the dynamic and uneven DNA compaction along the chromatin fiber. Since the DNA compaction level affects the transcription activity of a certain genomic region, it is important to understand the interplay between the factors acting at different levels of the packaging process. Drosophila polytene chromosomes are an excellent model system for studying the molecular mechanisms that determine DNA compaction degree. The unevenness of DNA packaging along the chromatin fiber is easily observed along these chromosomes due to their large size and specific banding pattern. The purpose of this study was to figure out the role of two non-histone regulatory proteins, ADF1 and BEAF-32, in the DNA packaging process from nucleosome positioning to the establishment of the final chromosome structure. We studied the impact of mutations that affect ADF1 and BEAF-32 binding sites on the formation of 61C7/C8 interband – one of the decompacted regions of Drosophila polytene chromosomes. We show that such mutations led to the collapse of an interband, which was accompanied with increased nucleosome stability. We also find that ADF1 and BEAF-32 binding sites are essential for the rescue of lethality caused by the null allele of bantam microRNA gene located in the region 61C7/C8.
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45
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The same domain of Su(Hw) is required for enhancer blocking and direct promoter repression. Sci Rep 2019; 9:5314. [PMID: 30926937 PMCID: PMC6441048 DOI: 10.1038/s41598-019-41761-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 03/14/2019] [Indexed: 12/22/2022] Open
Abstract
Suppressor of Hairy-wing [Su(Hw)] is a DNA-binding architectural protein that participates in the organization of insulators and repression of promoters in Drosophila. This protein contains acidic regions at both ends and a central cluster of 12 zinc finger domains, some of which are involved in the specific recognition of the binding site. One of the well-described in vivo function of Su(Hw) is the repression of transcription of neuronal genes in oocytes. Here, we have found that the same Su(Hw) C-terminal region (aa 720–892) is required for insulation as well as for promoter repression. The best characterized partners of Su(Hw), CP190 and Mod(mdg4)-67.2, are not involved in the repression of neuronal genes. Taken together, these results suggest that an unknown protein or protein complex binds to the C-terminal region of Su(Hw) and is responsible for the direct repression activity of Su(Hw).
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46
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Chathoth KT, Zabet NR. Chromatin architecture reorganization during neuronal cell differentiation in Drosophila genome. Genome Res 2019; 29:613-625. [PMID: 30709849 PMCID: PMC6442379 DOI: 10.1101/gr.246710.118] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 01/23/2019] [Indexed: 12/14/2022]
Abstract
The organization of the genome into topologically associating domains (TADs) was shown to have a regulatory role in development and cellular function, but the mechanism involved in TAD establishment is still unclear. Here, we present the first high-resolution contact map of Drosophila neuronal cells (BG3) and identify different classes of TADs by comparing this to genome organization in embryonic cells (Kc167). We find that only some TADs are conserved in both cell lines, whereas the rest are cell-type–specific. This is supported by a change in the enrichment of architectural proteins at TAD borders, with BEAF-32 present in embryonic cells and CTCF in neuronal cells. Furthermore, we observe strong divergent transcription, together with RNA Polymerase II occupancy and an increase in DNA accessibility at the TAD borders. TAD borders that are specific to neuronal cells are enriched in enhancers controlled by neuronal-specific transcription factors. Our results suggest that TADs are dynamic across developmental stages and reflect the interplay between insulators, transcriptional states, and enhancer activities.
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Affiliation(s)
- Keerthi T Chathoth
- School of Biological Sciences, University of Essex, Colchester, CO4 3SQ, United Kingdom
| | - Nicolae Radu Zabet
- School of Biological Sciences, University of Essex, Colchester, CO4 3SQ, United Kingdom
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47
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Fedotova A, Clendinen C, Bonchuk A, Mogila V, Aoki T, Georgiev P, Schedl P. Functional dissection of the developmentally restricted BEN domain chromatin boundary factor Insensitive. Epigenetics Chromatin 2019; 12:2. [PMID: 30602385 PMCID: PMC6317261 DOI: 10.1186/s13072-018-0249-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 12/19/2018] [Indexed: 02/06/2023] Open
Abstract
Background Boundaries in the Drosophila bithorax complex delimit autonomous regulatory domains that activate the parasegment (PS)-specific expression of homeotic genes. The Fab-7 boundary separates the iab-6 and iab-7 regulatory domains that control Abd-B expression in PS11 and PS12. This boundary is composed of multiple functionally redundant elements and has two key activities: it blocks crosstalk between iab-6 and iab-7 and facilitates boundary bypass. Results Here, we have used a structure–function approach to elucidate the biochemical properties and the in vivo activities of a conserved BEN domain protein, Insensitive, that is associated with Fab-7. Our biochemical studies indicate that in addition to the C-terminal BEN DNA-binding domain, Insv has two domains that mediate multimerization: one is a coiled-coil domain in the N-terminus, and the other is next to the BEN domain. These multimerization domains enable Insv to bind simultaneously to two canonical 8-bp recognition motifs, as well as to a ~ 100-bp non-canonical recognition sequence. They also mediate the assembly of higher-order multimers in the presence of DNA. Transgenic proteins lacking the N-terminal coiled-coil domain are compromised for boundary function in vivo. We also show that Insv interacts directly with CP190, a protein previously implicated in the boundary functions of several DNA-binding proteins, including Su(Hw) and dCTCF. While CP190 interaction is required for Insv binding to a subset of sites on polytene chromosomes, it has only a minor role in the boundary activity of Insv in the context of Fab-7. Conclusions The subdivision of eukaryotic chromosomes into discrete topological domains depends upon the pairing of boundary elements. In flies, pairing interactions are specific and typically orientation dependent. They occur in cis between neighboring heterologous boundaries, and in trans between homologous boundaries. One potential mechanism for ensuring pairing-interaction specificity is the use of sequence-specific DNA-binding proteins that can bind simultaneously with two or more recognition sequences. Our studies indicate that Insv can assemble into a multivalent DNA-binding complex and that the N-terminal Insv multimerization domain is critical for boundary function. Electronic supplementary material The online version of this article (10.1186/s13072-018-0249-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anna Fedotova
- Department of Genetics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Chaevia Clendinen
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Artem Bonchuk
- Department of Genetics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Vladic Mogila
- Department of Genetics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Tsutomu Aoki
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Pavel Georgiev
- Department of Genetics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.
| | - Paul Schedl
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
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48
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Harding K, White K. Drosophila as a Model for Developmental Biology: Stem Cell-Fate Decisions in the Developing Nervous System. J Dev Biol 2018; 6:E25. [PMID: 30347666 PMCID: PMC6315890 DOI: 10.3390/jdb6040025] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 10/16/2018] [Accepted: 10/17/2018] [Indexed: 12/25/2022] Open
Abstract
Stem cells face a diversity of choices throughout their lives. At specific times, they may decide to initiate cell division, terminal differentiation, or apoptosis, or they may enter a quiescent non-proliferative state. Neural stem cells in the Drosophila central nervous system do all of these, at stereotypical times and anatomical positions during development. Distinct populations of neural stem cells offer a unique system to investigate the regulation of a particular stem cell behavior, while comparisons between populations can lead us to a broader understanding of stem cell identity. Drosophila is a well-described and genetically tractable model for studying fundamental stem cell behavior and the mechanisms that underlie cell-fate decisions. This review will focus on recent advances in our understanding of the factors that contribute to distinct stem cell-fate decisions within the context of the Drosophila nervous system.
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Affiliation(s)
- Katherine Harding
- Massachusetts General Hospital Cutaneous Biology Research Center, Harvard Medical School, Boston, MA 02129, USA
| | - Kristin White
- Massachusetts General Hospital Cutaneous Biology Research Center, Harvard Medical School, Boston, MA 02129, USA.
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49
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Laktionov PP, Maksimov DA, Romanov SE, Antoshina PA, Posukh OV, White-Cooper H, Koryakov DE, Belyakin SN. Genome-wide analysis of gene regulation mechanisms during Drosophila spermatogenesis. Epigenetics Chromatin 2018; 11:14. [PMID: 29609617 PMCID: PMC5879934 DOI: 10.1186/s13072-018-0183-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 03/22/2018] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND During Drosophila spermatogenesis, testis-specific meiotic arrest complex (tMAC) and testis-specific TBP-associated factors (tTAF) contribute to activation of hundreds of genes required for meiosis and spermiogenesis. Intriguingly, tMAC is paralogous to the broadly expressed complex Myb-MuvB (MMB)/dREAM and Mip40 protein is shared by both complexes. tMAC acts as a gene activator in spermatocytes, while MMB/dREAM was shown to repress gene activity in many cell types. RESULTS Our study addresses the intricate interplay between tMAC, tTAF, and MMB/dREAM during spermatogenesis. We used cell type-specific DamID to build the DNA-binding profiles of Cookie monster (tMAC), Cannonball (tTAF), and Mip40 (MMB/dREAM and tMAC) proteins in male germline cells. Incorporating the whole transcriptome analysis, we characterized the regulatory effects of these proteins and identified their gene targets. This analysis revealed that tTAFs complex is involved in activation of achi, vis, and topi meiosis arrest genes, implying that tTAFs may indirectly contribute to the regulation of Achi, Vis, and Topi targets. To understand the relationship between tMAC and MMB/dREAM, we performed Mip40 DamID in tTAF- and tMAC-deficient mutants demonstrating meiosis arrest phenotype. DamID profiles of Mip40 were highly dynamic across the stages of spermatogenesis and demonstrated a strong dependence on tMAC in spermatocytes. Integrative analysis of our data indicated that MMB/dREAM represses genes that are not expressed in spermatogenesis, whereas tMAC recruits Mip40 for subsequent gene activation in spermatocytes. CONCLUSIONS Discovered interdependencies allow to formulate a renewed model for tMAC and tTAFs action in Drosophila spermatogenesis demonstrating how tissue-specific genes are regulated.
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Affiliation(s)
- Petr P Laktionov
- Institute of Molecular and Cellular Biology SB RAS, 8/2 Lavrentyev Ave, Novosibirsk, Russia, 630090
| | - Daniil A Maksimov
- Institute of Molecular and Cellular Biology SB RAS, 8/2 Lavrentyev Ave, Novosibirsk, Russia, 630090
| | - Stanislav E Romanov
- Institute of Molecular and Cellular Biology SB RAS, 8/2 Lavrentyev Ave, Novosibirsk, Russia, 630090
| | - Polina A Antoshina
- Institute of Molecular and Cellular Biology SB RAS, 8/2 Lavrentyev Ave, Novosibirsk, Russia, 630090
| | - Olga V Posukh
- Institute of Molecular and Cellular Biology SB RAS, 8/2 Lavrentyev Ave, Novosibirsk, Russia, 630090
| | | | - Dmitry E Koryakov
- Institute of Molecular and Cellular Biology SB RAS, 8/2 Lavrentyev Ave, Novosibirsk, Russia, 630090.,Novosibirsk State University, Novosibirsk, Russia, 630090
| | - Stepan N Belyakin
- Institute of Molecular and Cellular Biology SB RAS, 8/2 Lavrentyev Ave, Novosibirsk, Russia, 630090. .,Novosibirsk State University, Novosibirsk, Russia, 630090.
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50
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Pokholkova GV, Demakov SA, Andreenkov OV, Andreenkova NG, Volkova EI, Belyaeva ES, Zhimulev IF. Tethering of CHROMATOR and dCTCF proteins results in decompaction of condensed bands in the Drosophila melanogaster polytene chromosomes but does not affect their transcription and replication timing. PLoS One 2018; 13:e0192634. [PMID: 29608600 PMCID: PMC5880345 DOI: 10.1371/journal.pone.0192634] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 01/26/2018] [Indexed: 01/20/2023] Open
Abstract
Instulator proteins are central to domain organization and gene regulation in the genome. We used ectopic tethering of CHROMATOR (CHRIZ/CHRO) and dCTCF to pre-defined regions of the genome to dissect the influence of these proteins on local chromatin organization, to analyze their interaction with other key chromatin proteins and to evaluate the effects on transcription and replication. Specifically, using UAS-GAL4DBD system, CHRO and dCTCF were artificially recruited into highly compacted polytene chromosome bands that share the features of silent chromatin type known as intercalary heterochromatin (IH). This led to local chromatin decondensation, formation of novel DHSes and recruitment of several "open chromatin" proteins. CHRO tethering resulted in the recruitment of CP190 and Z4 (PZG), whereas dCTCF tethering attracted CHRO, CP190, and Z4. Importantly, formation of a local stretch of open chromatin did not result in the reactivation of silent marker genes yellow and mini-white immediately adjacent to the targeting region (UAS), nor did RNA polII become recruited into this chromatin. The decompacted region retained late replicated, similarly to the wild-type untargeted region.
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Affiliation(s)
- Galina V. Pokholkova
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences (IMCB RAS), Novosibirsk, Russia
| | - Sergei A. Demakov
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences (IMCB RAS), Novosibirsk, Russia
- Novosibirsk State University (NSU), Novosibirsk, Russia
| | - Oleg V. Andreenkov
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences (IMCB RAS), Novosibirsk, Russia
| | - Natalia G. Andreenkova
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences (IMCB RAS), Novosibirsk, Russia
| | - Elena I. Volkova
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences (IMCB RAS), Novosibirsk, Russia
| | - Elena S. Belyaeva
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences (IMCB RAS), Novosibirsk, Russia
| | - Igor F. Zhimulev
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences (IMCB RAS), Novosibirsk, Russia
- Novosibirsk State University (NSU), Novosibirsk, Russia
- * E-mail:
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