1
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Crain AT, Butler MB, Hill CA, Huynh M, McGinty RK, Duronio RJ. Drosophila melanogaster Set8 and L(3)mbt function in gene expression independently of histone H4 lysine 20 methylation. Genes Dev 2024; 38:455-472. [PMID: 38866557 PMCID: PMC11216177 DOI: 10.1101/gad.351698.124] [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: 03/12/2024] [Accepted: 05/29/2024] [Indexed: 06/14/2024]
Abstract
Monomethylation of lysine 20 of histone H4 (H4K20me1) is catalyzed by Set8 and thought to play important roles in many aspects of genome function that are mediated by H4K20me binding proteins. We interrogated this model in a developing animal by comparing in parallel the transcriptomes of Set8 null , H4 K20R/A , and l(3)mbt mutant Drosophila melanogaster We found that the gene expression profiles of H4 K20A and H4 K20R larvae are markedly different than Set8 null larvae despite similar reductions in H4K20me1. Set8 null mutant cells have a severely disrupted transcriptome and fail to proliferate in vivo, but these phenotypes are not recapitulated by mutation of H4 K20 , indicating that the developmental defects of Set8 null animals are largely due to H4K20me1-independent effects on gene expression. Furthermore, the H4K20me1 binding protein L(3)mbt is recruited to the transcription start sites of most genes independently of H4K20me even though genes bound by L(3)mbt have high levels of H4K20me1. Moreover, both Set8 and L(3)mbt bind to purified H4K20R nucleosomes in vitro. We conclude that gene expression changes in Set8 null and H4 K20 mutants cannot be explained by loss of H4K20me1 or L(3)mbt binding to chromatin and therefore that H4K20me1 does not play a large role in gene expression.
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Affiliation(s)
- Aaron T Crain
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina 27599 USA
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, North Carolina 27599 USA
| | - Megan B Butler
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599 USA
| | - Christina A Hill
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, North Carolina 27599 USA
| | - Mai Huynh
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599 USA
- Division of Chemical Biology and Medicinal Chemistry, Center for Integrative Chemical Biology and Drug Discovery, University of North Carolina Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599 USA
| | - Robert K McGinty
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599 USA
- Division of Chemical Biology and Medicinal Chemistry, Center for Integrative Chemical Biology and Drug Discovery, University of North Carolina Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599 USA
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599 USA
| | - Robert J Duronio
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina 27599 USA;
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, North Carolina 27599 USA
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599 USA
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599 USA
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599 USA
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2
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Crain AT, Butler MB, Hill CA, Huynh M, McGinty RK, Duronio RJ. Drosophila melanogaster Set8 and L(3)mbt function in gene expression independently of histone H4 lysine 20 methylation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.12.584710. [PMID: 38559189 PMCID: PMC10980064 DOI: 10.1101/2024.03.12.584710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Mono-methylation of Lysine 20 of histone H4 (H4K20me1) is catalyzed by Set8 and thought to play important roles in many aspects of genome function that are mediated by H4K20me-binding proteins. We interrogated this model in a developing animal by comparing in parallel the transcriptomes of Set8 null , H4 K20R/A , and l(3)mbt mutant Drosophila melanogaster . We found that the gene expression profiles of H4 K20A and H4 K20R larvae are markedly different than Set8 null larvae despite similar reductions in H4K20me1. Set8 null mutant cells have a severely disrupted transcriptome and fail to proliferate in vivo , but these phenotypes are not recapitulated by mutation of H4 K20 indicating that the developmental defects of Set8 null animals are largely due to H4K20me1-independent effects on gene expression. Further, the H4K20me1 binding protein L(3)mbt is recruited to the transcription start sites of most genes independently of H4K20me even though genes bound by L(3)mbt have high levels of H4K20me1. Moreover, both Set8 and L(3)mbt bind to purified H4K20R nucleosomes in vitro. We conclude that gene expression changes in Set8 null and H4 K20 mutants cannot be explained by loss of H4K20me1 or L(3)mbt binding to chromatin, and therefore that H4K20me1 does not play a large role in gene expression.
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3
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Hoareau M, Rincheval-Arnold A, Gaumer S, Guénal I. DREAM a little dREAM of DRM: Model organisms and conservation of DREAM-like complexes: Model organisms uncover the mechanisms of DREAM-mediated transcription regulation. Bioessays 2024; 46:e2300125. [PMID: 38059789 DOI: 10.1002/bies.202300125] [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: 07/07/2023] [Revised: 11/23/2023] [Accepted: 11/24/2023] [Indexed: 12/08/2023]
Abstract
DREAM complexes are transcriptional regulators that control the expression of hundreds to thousands of target genes involved in the cell cycle, quiescence, differentiation, and apoptosis. These complexes contain many subunits that can vary according to the considered target genes. Depending on their composition and the nature of the partners they recruit, DREAM complexes control gene expression through diverse mechanisms, including chromatin remodeling, transcription cofactor and factor recruitment at various genomic binding sites. This complexity is particularly high in mammals. Since the discovery of the first dREAM complex (drosophila Rb, E2F, and Myb) in Drosophila melanogaster, model organisms such as Caenorhabditis elegans, and plants allowed a deeper understanding of the processes regulated by DREAM-like complexes. Here, we review the conservation of these complexes. We discuss the contribution of model organisms to the study of DREAM-mediated transcriptional regulatory mechanisms and their relevance in characterizing novel activities of DREAM complexes.
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Affiliation(s)
- Marion Hoareau
- Université Paris-Saclay, UVSQ, LGBC, Versailles, France
- Université PSL, EPHE, Paris, France
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4
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Egger B. Neural Stem Cells and Brain Tumour Models in Drosophila. Neurogenetics 2023. [DOI: 10.1007/978-3-031-07793-7_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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5
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Yamamoto‐Matsuda H, Miyoshi K, Moritoh M, Yoshitane H, Fukada Y, Saito K, Yamanaka S, Siomi MC. Lint‐O
cooperates with L(3)mbt in target gene suppression to maintain homeostasis in fly ovary and brain. EMBO Rep 2022; 23:e53813. [PMID: 35993198 PMCID: PMC9535798 DOI: 10.15252/embr.202153813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 08/08/2022] [Accepted: 08/09/2022] [Indexed: 11/23/2022] Open
Abstract
Loss‐of‐function mutations in Drosophila lethal(3)malignant brain tumor [l(3)mbt] cause ectopic expression of germline genes and brain tumors. Loss of L(3)mbt function in ovarian somatic cells (OSCs) aberrantly activates germ‐specific piRNA amplification and leads to infertility. However, the underlying mechanism remains unclear. Here, ChIP‐seq for L(3)mbt in cultured OSCs and RNA‐seq before and after L(3)mbt depletion shows that L(3)mbt genomic binding is not necessarily linked to gene regulation and that L(3)mbt controls piRNA pathway genes in multiple ways. Lack of known L(3)mbt co‐repressors, such as Lint‐1, has little effect on the levels of piRNA amplifiers. Identification of L(3)mbt interactors in OSCs and subsequent analysis reveals CG2662 as a novel co‐regulator of L(3)mbt, termed “L(3)mbt interactor in OSCs” (Lint‐O). Most of the L(3)mbt‐bound piRNA amplifier genes are also bound by Lint‐O in a similar fashion. Loss of Lint‐O impacts the levels of piRNA amplifiers, similar to the lack of L(3)mbt. The lint‐O‐deficient flies exhibit female sterility and tumorous brains. Thus, L(3)mbt and its novel co‐suppressor Lint‐O cooperate in suppressing target genes to maintain homeostasis in the ovary and brain.
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Affiliation(s)
- Hitomi Yamamoto‐Matsuda
- Department of Biological Sciences, Graduate School of Science The University of Tokyo Tokyo Japan
| | - Keita Miyoshi
- Department of Chromosome Science National Institute of Genetics, Research Organization of Information and Systems Shizuoka Japan
- Department of Genetics School of Life Science, SOKENDAI Shizuoka Japan
| | - Mai Moritoh
- Department of Biological Sciences, Graduate School of Science The University of Tokyo Tokyo Japan
| | - Hikari Yoshitane
- Department of Biological Sciences, Graduate School of Science The University of Tokyo Tokyo Japan
| | - Yoshitaka Fukada
- Department of Biological Sciences, Graduate School of Science The University of Tokyo Tokyo Japan
| | - Kuniaki Saito
- Department of Chromosome Science National Institute of Genetics, Research Organization of Information and Systems Shizuoka Japan
- Department of Genetics School of Life Science, SOKENDAI Shizuoka Japan
| | - Soichiro Yamanaka
- Department of Biological Sciences, Graduate School of Science The University of Tokyo Tokyo Japan
| | - Mikiko C Siomi
- Department of Biological Sciences, Graduate School of Science The University of Tokyo Tokyo Japan
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6
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Oxidative Stress Is Associated with Overgrowth in Drosophila l(3)mbt Mutant Imaginal Discs. Cells 2022; 11:cells11162542. [PMID: 36010619 PMCID: PMC9406541 DOI: 10.3390/cells11162542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/04/2022] [Accepted: 08/13/2022] [Indexed: 11/17/2022] Open
Abstract
The loss-of-function conditions for an l(3)malignant brain tumour (l(3)mbt) in larvae reared at 29 °C results in malignant brain tumours and hyperplastic imaginal discs. Unlike the former that have been extensively characterised, little is known about the latter. Here we report the results of a study of the hyperplastic l(3)mbt mutant wing imaginal discs. We identify the l(3)mbt wing disc tumour transcriptome and find it to include genes involved in reactive oxygen species (ROS) metabolism. Furthermore, we show the presence of oxidative stress in l(3)mbt hyperplastic discs, even in apoptosis-blocked conditions, but not in l(3)mbt brain tumours. We also find that chemically blocking oxidative stress in l(3)mbt wing discs reduces the incidence of wing disc overgrowths. Our results reveal the involvement of oxidative stress in l(3)mbt wing discs hyperplastic growth.
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7
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Abstract
Notch signalling is a well-conserved signalling pathway that regulates cell fate through cell-cell communication. A typical feature of Notch signalling is ‘lateral inhibition’, whereby two neighbouring cells of equivalent state of differentiation acquire different cell fates. Recently, mathematical and computational approaches have addressed the Notch dynamics in Drosophila neural development. Typical examples of lateral inhibition are observed in the specification of neural stem cells in the embryo and sensory organ precursors in the thorax. In eye disc development, Notch signalling cooperates with other signalling pathways to define the evenly spaced positioning of the photoreceptor cells. The interplay between Notch and epidermal growth factor receptor signalling regulates the timing of neural stem cell differentiation in the optic lobe. In this review, we summarize the theoretical studies that have been conducted to elucidate the Notch dynamics in these systems and discuss the advantages of combining mathematical models with biological experiments.
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Affiliation(s)
- Tetsuo Yasugi
- Mathematical Neuroscience Unit, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Makoto Sato
- Mathematical Neuroscience Unit, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Ishikawa, Japan.,Laboratory of Developmental Neurobiology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan
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8
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Abstract
AbstractIn the developing Drosophila CNS, two pools of neural stem cells, the symmetrically dividing progenitors in the neuroepithelium (NE) and the asymmetrically dividing neuroblasts (NBs) generate the majority of the neurons that make up the adult central nervous system (CNS). The generation of a correct sized brain depends on maintaining the fine balance between neural stem cell self-renewal and differentiation, which are regulated by cell-intrinsic and cell-extrinsic cues. In this review, we will discuss our current understanding of how self-renewal and differentiation are regulated in the two neural stem cell pools, and the consequences of the deregulation of these processes.
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Affiliation(s)
- Francesca Froldi
- Peter MacCallum Cancer Centre, East Melbourne, Victoria, 3002, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Victoria, 3010, Australia
| | - Milán Szuperák
- Peter MacCallum Cancer Centre, East Melbourne, Victoria, 3002, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Victoria, 3010, Australia
| | - Louise Y. Cheng
- Peter MacCallum Cancer Centre, East Melbourne, Victoria, 3002, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Victoria, 3010, Australia
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9
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Magadi SS, Voutyraki C, Anagnostopoulos G, Zacharioudaki E, Poutakidou IK, Efraimoglou C, Stapountzi M, Theodorou V, Nikolaou C, Koumbanakis KA, Fullard JF, Delidakis C. Dissecting Hes-centred transcriptional networks in neural stem cell maintenance and tumorigenesis in Drosophila. Development 2020; 147:147/22/dev191544. [PMID: 33229432 DOI: 10.1242/dev.191544] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 10/05/2020] [Indexed: 01/26/2023]
Abstract
Neural stem cells divide during embryogenesis and juvenile life to generate the entire complement of neurons and glia in the nervous system of vertebrates and invertebrates. Studies of the mechanisms controlling the fine balance between neural stem cells and more differentiated progenitors have shown that, in every asymmetric cell division, progenitors send a Delta-Notch signal to their sibling stem cells. Here, we show that excessive activation of Notch or overexpression of its direct targets of the Hes family causes stem-cell hyperplasias in the Drosophila larval central nervous system, which can progress to malignant tumours after allografting to adult hosts. We combined transcriptomic data from these hyperplasias with chromatin occupancy data for Dpn, a Hes transcription factor, to identify genes regulated by Hes factors in this process. We show that the Notch/Hes axis represses a cohort of transcription factor genes. These are excluded from the stem cells and promote early differentiation steps, most likely by preventing the reversion of immature progenitors to a stem-cell fate. We describe the impact of two of these 'anti-stemness' factors, Zfh1 and Gcm, on Notch/Hes-triggered tumorigenesis.
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Affiliation(s)
- Srivathsa S Magadi
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece.,Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
| | - Chrysanthi Voutyraki
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece.,Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
| | - Gerasimos Anagnostopoulos
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece.,Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
| | - Evanthia Zacharioudaki
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece
| | - Ioanna K Poutakidou
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece.,Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
| | - Christina Efraimoglou
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece.,Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
| | - Margarita Stapountzi
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece
| | - Vasiliki Theodorou
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece
| | - Christoforos Nikolaou
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece.,Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
| | - Konstantinos A Koumbanakis
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece.,Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
| | - John F Fullard
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece
| | - Christos Delidakis
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece .,Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
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10
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A continuation method for spatially discretized models with nonlocal interactions conserving size and shape of cells and lattices. J Math Biol 2020; 81:981-1028. [PMID: 32959067 PMCID: PMC7560951 DOI: 10.1007/s00285-020-01534-6] [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: 01/10/2020] [Revised: 07/15/2020] [Indexed: 11/18/2022]
Abstract
In this paper, we introduce a continuation method for the spatially discretized models, while conserving the size and shape of the cells and lattices. This proposed method is realized using the shift operators and nonlocal operators of convolution types. Through this method and using the shift operator, the nonlinear spatially discretized model on the uniform and nonuniform lattices can be systematically converted into a spatially continuous model; this renders both models point-wisely equivalent. Moreover, by the convolution with suitable kernels, we mollify the shift operator and approximate the spatially discretized models using the nonlocal evolution equations, rendering suitable for the application in both experimental and mathematical analyses. We also demonstrate that this approximation is supported by the singular limit analysis, and that the information of the lattice and cells is expressed in the shift and nonlocal operators. The continuous models designed using our method can successfully replicate the patterns corresponding to those of the original spatially discretized models obtained from the numerical simulations. Furthermore, from the observations of the isotropy of the Delta–Notch signaling system in a developing real fly brain, we propose a radially symmetric kernel for averaging the cell shape using our continuation method. We also apply our method for cell division and proliferation to spatially discretized models of the differentiation wave and describe the discrete models on the sphere surface. Finally, we demonstrate an application of our method in the linear stability analysis of the planar cell polarity model.
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11
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Kozako T, Itoh Y, Honda SI, Suzuki T. Epigenetic Control Using Small Molecules in Cancer. ACTA ACUST UNITED AC 2020. [DOI: 10.1007/978-3-030-32857-3_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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12
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Mačinković I, Theofel I, Hundertmark T, Kovač K, Awe S, Lenz J, Forné I, Lamp B, Nist A, Imhof A, Stiewe T, Renkawitz-Pohl R, Rathke C, Brehm A. Distinct CoREST complexes act in a cell-type-specific manner. Nucleic Acids Res 2019; 47:11649-11666. [PMID: 31701127 PMCID: PMC7145674 DOI: 10.1093/nar/gkz1050] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 10/16/2019] [Accepted: 10/23/2019] [Indexed: 01/10/2023] Open
Abstract
CoREST has been identified as a subunit of several protein complexes that generate transcriptionally repressive chromatin structures during development. However, a comprehensive analysis of the CoREST interactome has not been carried out. We use proteomic approaches to define the interactomes of two dCoREST isoforms, dCoREST-L and dCoREST-M, in Drosophila. We identify three distinct histone deacetylase complexes built around a common dCoREST/dRPD3 core: A dLSD1/dCoREST complex, the LINT complex and a dG9a/dCoREST complex. The latter two complexes can incorporate both dCoREST isoforms. By contrast, the dLSD1/dCoREST complex exclusively assembles with the dCoREST-L isoform. Genome-wide studies show that the three dCoREST complexes associate with chromatin predominantly at promoters. Transcriptome analyses in S2 cells and testes reveal that different cell lineages utilize distinct dCoREST complexes to maintain cell-type-specific gene expression programmes: In macrophage-like S2 cells, LINT represses germ line-related genes whereas other dCoREST complexes are largely dispensable. By contrast, in testes, the dLSD1/dCoREST complex prevents transcription of germ line-inappropriate genes and is essential for spermatogenesis and fertility, whereas depletion of other dCoREST complexes has no effect. Our study uncovers three distinct dCoREST complexes that function in a lineage-restricted fashion to repress specific sets of genes thereby maintaining cell-type-specific gene expression programmes.
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Affiliation(s)
- Igor Mačinković
- Institute of Molecular Biology and Tumor Research, Biomedical Research Center, Philipps-University, Hans-Meerwein-Strasse 2, 35043, Marburg, Germany
| | - Ina Theofel
- Department of Biology, Philipps-University, Karl-von-Frisch-Strasse 8, 35043, Marburg, Germany
| | - Tim Hundertmark
- Department of Biology, Philipps-University, Karl-von-Frisch-Strasse 8, 35043, Marburg, Germany
| | - Kristina Kovač
- Institute of Molecular Biology and Tumor Research, Biomedical Research Center, Philipps-University, Hans-Meerwein-Strasse 2, 35043, Marburg, Germany
| | - Stephan Awe
- Institute of Molecular Biology and Tumor Research, Biomedical Research Center, Philipps-University, Hans-Meerwein-Strasse 2, 35043, Marburg, Germany
| | - Jonathan Lenz
- Institute of Molecular Biology and Tumor Research, Biomedical Research Center, Philipps-University, Hans-Meerwein-Strasse 2, 35043, Marburg, Germany
| | - Ignasi Forné
- Protein Analysis Unit, BioMedical Center, Faculty of Medicine, Ludwig-Maximilians-University Munich, Großhadernerstrasse 9, 82152 Martinsried, Germany
| | - Boris Lamp
- Genomics Core Facility, Institute of Molecular Oncology, Philipps-University, Hans-Meerwein-Strasse 3, 35043 Marburg, Germany
| | - Andrea Nist
- Genomics Core Facility, Institute of Molecular Oncology, Philipps-University, Hans-Meerwein-Strasse 3, 35043 Marburg, Germany
| | - Axel Imhof
- Protein Analysis Unit, BioMedical Center, Faculty of Medicine, Ludwig-Maximilians-University Munich, Großhadernerstrasse 9, 82152 Martinsried, Germany
| | - Thorsten Stiewe
- Genomics Core Facility, Institute of Molecular Oncology, Philipps-University, Hans-Meerwein-Strasse 3, 35043 Marburg, Germany
| | - Renate Renkawitz-Pohl
- Department of Biology, Philipps-University, Karl-von-Frisch-Strasse 8, 35043, Marburg, Germany
| | - Christina Rathke
- Department of Biology, Philipps-University, Karl-von-Frisch-Strasse 8, 35043, Marburg, Germany
| | - Alexander Brehm
- Institute of Molecular Biology and Tumor Research, Biomedical Research Center, Philipps-University, Hans-Meerwein-Strasse 2, 35043, Marburg, Germany
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13
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Molnar C, Heinen JP, Reina J, Llamazares S, Palumbo E, Breschi A, Gay M, Villarreal L, Vilaseca M, Pollarolo G, Gonzalez C. The histone code reader PHD finger protein 7 controls sex-linked disparities in gene expression and malignancy in Drosophila. SCIENCE ADVANCES 2019; 5:eaaw7965. [PMID: 31453329 PMCID: PMC6693905 DOI: 10.1126/sciadv.aaw7965] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 07/11/2019] [Indexed: 05/03/2023]
Abstract
The notable male predominance across many human cancer types remains unexplained. Here, we show that Drosophila l(3)mbt brain tumors are more invasive and develop as malignant neoplasms more often in males than in females. By quantitative proteomics, we have identified a signature of proteins that are differentially expressed between male and female tumor samples. Prominent among them is the conserved chromatin reader PHD finger protein 7 (Phf7). We show that Phf7 depletion reduces sex-dependent differences in gene expression and suppresses the enhanced malignant traits of male tumors. Our results identify potential regulators of sex-linked tumor dimorphism and show that these genes may serve as targets to suppress sex-linked malignant traits.
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Affiliation(s)
- Cristina Molnar
- IRB Barcelona, BIST, Carrer de Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Jan Peter Heinen
- IRB Barcelona, BIST, Carrer de Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Jose Reina
- IRB Barcelona, BIST, Carrer de Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Salud Llamazares
- IRB Barcelona, BIST, Carrer de Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Emilio Palumbo
- CRG, BIST, Carrer del Dr. Aiguader, 88, 08003 Barcelona, Spain
- UPF, Plaça de la Mercè, 10, 08002 Barcelona, Spain
- IMIM, Carrer del Dr. Aiguader, 88, 08003 Barcelona, Spain
| | | | - Marina Gay
- IRB Barcelona, BIST, Carrer de Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Laura Villarreal
- IRB Barcelona, BIST, Carrer de Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Marta Vilaseca
- IRB Barcelona, BIST, Carrer de Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Giulia Pollarolo
- IRB Barcelona, BIST, Carrer de Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Cayetano Gonzalez
- IRB Barcelona, BIST, Carrer de Baldiri Reixac, 10, 08028 Barcelona, Spain
- ICREA, Passeig Lluís Companys, 08010 Barcelona, Spain
- Corresponding author.
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14
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Hakes AE, Brand AH. Neural stem cell dynamics: the development of brain tumours. Curr Opin Cell Biol 2019; 60:131-138. [PMID: 31330360 DOI: 10.1016/j.ceb.2019.06.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 06/07/2019] [Accepted: 06/11/2019] [Indexed: 02/08/2023]
Abstract
Determining the premalignant lesions that develop into malignant tumours remains a daunting task. Brain tumours are frequently characterised by a block in differentiation, implying that normal developmental pathways become hijacked during tumourigenesis. However, the heterogeneity of stem cells and their progenitors in the brain suggests there are many potential routes to tumour initiation. Studies in Drosophila melanogaster have enhanced our understanding of the tumourigenic potential of distinct cell types in the brain. Here we review recent studies that have improved our knowledge of neural stem cell behaviour during development and in brain tumour models.
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Affiliation(s)
- Anna E Hakes
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Andrea H Brand
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK.
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15
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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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16
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Hakes AE, Otsuki L, Brand AH. A newly discovered neural stem cell population is generated by the optic lobe neuroepithelium during embryogenesis in Drosophila melanogaster. Development 2018; 145:145/18/dev166207. [PMID: 30254066 PMCID: PMC6176933 DOI: 10.1242/dev.166207] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 08/24/2018] [Indexed: 12/21/2022]
Abstract
Neural stem cells must balance symmetric and asymmetric cell divisions to generate a functioning brain of the correct size. In both the developing Drosophila visual system and mammalian cerebral cortex, symmetrically dividing neuroepithelial cells transform gradually into asymmetrically dividing progenitors that generate neurons and glia. As a result, it has been widely accepted that stem cells in these tissues switch from a symmetric, expansive phase of cell divisions to a later neurogenic phase of cell divisions. In the Drosophila optic lobe, this switch is thought to occur during larval development. However, we have found that neuroepithelial cells start to produce neuroblasts during embryonic development, demonstrating a much earlier role for neuroblasts in the developing visual system. These neuroblasts undergo neurogenic divisions, enter quiescence and are retained post-embryonically, together with neuroepithelial cells. Later in development, neuroepithelial cells undergo further cell divisions before transforming into larval neuroblasts. Our results demonstrate that the optic lobe neuroepithelium gives rise to neurons and glia over 60 h earlier than was thought previously. Highlighted Article: Two types of neural stem cell, with distinct proliferation modes, act side by side to generate the Drosophila optic lobe, challenging current dogma that they act sequentially.
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Affiliation(s)
- Anna E Hakes
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Leo Otsuki
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Andrea H Brand
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
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17
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Rossi F, Molnar C, Hashiyama K, Heinen JP, Pampalona J, Llamazares S, Reina J, Hashiyama T, Rai M, Pollarolo G, Fernández-Hernández I, Gonzalez C. An in vivo genetic screen in Drosophila identifies the orthologue of human cancer/testis gene SPO11 among a network of targets to inhibit lethal(3)malignant brain tumour growth. Open Biol 2018; 7:rsob.170156. [PMID: 28855394 PMCID: PMC5577452 DOI: 10.1098/rsob.170156] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2017] [Accepted: 07/27/2017] [Indexed: 12/31/2022] Open
Abstract
Using transgenic RNAi technology, we have screened over 4000 genes to identify targets to inhibit malignant growth caused by the loss of function of lethal(3)malignant brain tumour in Drosophila in vivo. We have identified 131 targets, which belong to a wide range of gene ontologies. Most of these target genes are not significantly overexpressed in mbt tumours hence showing that, rather counterintuitively, tumour-linked overexpression is not a good predictor of functional requirement. Moreover, we have found that most of the genes upregulated in mbt tumours remain overexpressed in tumour-suppressed double-mutant conditions, hence revealing that most of the tumour transcriptome signature is not necessarily correlated with malignant growth. One of the identified target genes is meiotic W68 (mei-W68), the Drosophila orthologue of the human cancer/testis gene Sporulation-specific protein 11 (SPO11), the enzyme that catalyses the formation of meiotic double-strand breaks. We show that Drosophila mei-W68/SPO11 drives oncogenesis by causing DNA damage in a somatic tissue, hence providing the first instance in which a SPO11 orthologue is unequivocally shown to have a pro-tumoural role. Altogether, the results from this screen point to the possibility of investigating the function of human cancer relevant genes in a tractable experimental model organism like Drosophila.
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Affiliation(s)
- Fabrizio Rossi
- Cell Division Group, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Cristina Molnar
- Cell Division Group, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Kazuya Hashiyama
- Cell Division Group, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Jan P Heinen
- Cell Division Group, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Judit Pampalona
- Cell Division Group, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Salud Llamazares
- Cell Division Group, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - José Reina
- Cell Division Group, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Tomomi Hashiyama
- Cell Division Group, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Madhulika Rai
- Cell Division Group, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Giulia Pollarolo
- Cell Division Group, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Ismael Fernández-Hernández
- Cell Division Group, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Cayetano Gonzalez
- Cell Division Group, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain .,Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys, 08010 Barcelona, Spain
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18
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Coux RX, Teixeira FK, Lehmann R. L(3)mbt and the LINT complex safeguard cellular identity in the Drosophila ovary. Development 2018; 145:dev.160721. [PMID: 29511022 PMCID: PMC5963868 DOI: 10.1242/dev.160721] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 02/19/2018] [Indexed: 01/10/2023]
Abstract
Maintenance of cellular identity is essential for tissue development and homeostasis. At the molecular level, cell identity is determined by the coordinated activation and repression of defined sets of genes. The tumor suppressor L(3)mbt has been shown to secure cellular identity in Drosophila larval brains by repressing germline-specific genes. Here, we interrogate the temporal and spatial requirements for L(3)mbt in the Drosophila ovary, and show that it safeguards the integrity of both somatic and germline tissues. l(3)mbt mutant ovaries exhibit multiple developmental defects, which we find to be largely caused by the inappropriate expression of a single gene, nanos, a key regulator of germline fate, in the somatic ovarian cells. In the female germline, we find that L(3)mbt represses testis-specific and neuronal genes. At the molecular level, we show that L(3)mbt function in the ovary is mediated through its co-factor Lint-1 but independently of the dREAM complex. Together, our work uncovers a more complex role for L(3)mbt than previously understood and demonstrates that L(3)mbt secures tissue identity by preventing the simultaneous expression of original identity markers and tissue-specific misexpression signatures. Highlighted Article: Characterization of the developmental defects of l(3)mbt mutant ovaries shows that L(3)mbt regulates tissue-specific gene signatures to secure the identity of somatic ovarian and germline tissues.
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Affiliation(s)
- Rémi-Xavier Coux
- Howard Hughes Medical Institute (HHMI) and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
| | - Felipe Karam Teixeira
- Howard Hughes Medical Institute (HHMI) and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA.,Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK
| | - Ruth Lehmann
- Howard Hughes Medical Institute (HHMI) and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
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19
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Rossi F, Attolini CSO, Mosquera JL, Gonzalez C. Drosophila Larval Brain Neoplasms Present Tumour-Type Dependent Genome Instability. G3 (BETHESDA, MD.) 2018; 8:1205-1214. [PMID: 29467187 PMCID: PMC5873911 DOI: 10.1534/g3.117.300489] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 02/01/2018] [Indexed: 12/30/2022]
Abstract
Single nucleotide polymorphisms (SNPs) and copy number variants (CNVs) are found at different rates in human cancer. To determine if these genetic lesions appear in Drosophila tumors we have sequenced the genomes of 17 malignant neoplasms caused by mutations in l(3)mbt, brat, aurA, or lgl We have found CNVs and SNPs in all the tumors. Tumor-linked CNVs range between 11 and 80 per sample, affecting between 92 and 1546 coding sequences. CNVs are in average less frequent in l(3)mbt than in brat lines. Nearly half of the CNVs fall within the 10 to 100Kb range, all tumor samples contain CNVs larger that 100 Kb and some have CNVs larger than 1Mb. The rates of tumor-linked SNPs change more than 20-fold depending on the tumor type: at late time points brat, l(3)mbt, and aurA and lgl lines present median values of SNPs/Mb of exome of 0.16, 0.48, and 3.6, respectively. Higher SNP rates are mostly accounted for by C > A transversions, which likely reflect enhanced oxidative stress conditions in the affected tumors. Both CNVs and SNPs turn over rapidly. We found no evidence for selection of a gene signature affected by CNVs or SNPs in the cohort. Altogether, our results show that the rates of CNVs and SNPs, as well as the distribution of CNV sizes in this cohort of Drosophila tumors are well within the range of those reported for human cancer. Genome instability is therefore inherent to Drosophila malignant neoplastic growth at a variable extent that is tumor type dependent.
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Affiliation(s)
- Fabrizio Rossi
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Camille Stephan-Otto Attolini
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Jose Luis Mosquera
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
| | - Cayetano Gonzalez
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, 08028 Barcelona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain
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20
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Xu T, Park SS, Giaimo BD, Hall D, Ferrante F, Ho DM, Hori K, Anhezini L, Ertl I, Bartkuhn M, Zhang H, Milon E, Ha K, Conlon KP, Kuick R, Govindarajoo B, Zhang Y, Sun Y, Dou Y, Basrur V, Elenitoba-Johnson KS, Nesvizhskii AI, Ceron J, Lee CY, Borggrefe T, Kovall RA, Rual JF. RBPJ/CBF1 interacts with L3MBTL3/MBT1 to promote repression of Notch signaling via histone demethylase KDM1A/LSD1. EMBO J 2017; 36:3232-3249. [PMID: 29030483 PMCID: PMC5666606 DOI: 10.15252/embj.201796525] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 08/31/2017] [Accepted: 09/12/2017] [Indexed: 12/21/2022] Open
Abstract
Notch signaling is an evolutionarily conserved signal transduction pathway that is essential for metazoan development. Upon ligand binding, the Notch intracellular domain (NOTCH ICD) translocates into the nucleus and forms a complex with the transcription factor RBPJ (also known as CBF1 or CSL) to activate expression of Notch target genes. In the absence of a Notch signal, RBPJ acts as a transcriptional repressor. Using a proteomic approach, we identified L3MBTL3 (also known as MBT1) as a novel RBPJ interactor. L3MBTL3 competes with NOTCH ICD for binding to RBPJ. In the absence of NOTCH ICD, RBPJ recruits L3MBTL3 and the histone demethylase KDM1A (also known as LSD1) to the enhancers of Notch target genes, leading to H3K4me2 demethylation and to transcriptional repression. Importantly, in vivo analyses of the homologs of RBPJ and L3MBTL3 in Drosophila melanogaster and Caenorhabditis elegans demonstrate that the functional link between RBPJ and L3MBTL3 is evolutionarily conserved, thus identifying L3MBTL3 as a universal modulator of Notch signaling in metazoans.
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Affiliation(s)
- Tao Xu
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Sung-Soo Park
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - Daniel Hall
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | | | - Diana M Ho
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Kazuya Hori
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Lucas Anhezini
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Iris Ertl
- Cancer and Human Molecular Genetics, Bellvitge Biomedical Research Institute, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Marek Bartkuhn
- Institute for Genetics, University of Giessen, Giessen, Germany
| | - Honglai Zhang
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Eléna Milon
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Kimberly Ha
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Kevin P Conlon
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Rork Kuick
- Center for Cancer Biostatistics, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Brandon Govindarajoo
- Department of Computational Medicine & Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Yang Zhang
- Department of Computational Medicine & Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Yuqing Sun
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Yali Dou
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Venkatesha Basrur
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - Alexey I Nesvizhskii
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA.,Department of Computational Medicine & Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Julian Ceron
- Cancer and Human Molecular Genetics, Bellvitge Biomedical Research Institute, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Cheng-Yu Lee
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Tilman Borggrefe
- Institute of Biochemistry, University of Giessen, Giessen, Germany
| | - Rhett A Kovall
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Jean-François Rual
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
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21
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Paglia S, Sollazzo M, Di Giacomo S, de Biase D, Pession A, Grifoni D. Failure of the PTEN/aPKC/Lgl Axis Primes Formation of Adult Brain Tumours in Drosophila. BIOMED RESEARCH INTERNATIONAL 2017; 2017:2690187. [PMID: 29445734 PMCID: PMC5763105 DOI: 10.1155/2017/2690187] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 11/02/2017] [Accepted: 11/08/2017] [Indexed: 02/05/2023]
Abstract
Different regions in the mammalian adult brain contain immature precursors, reinforcing the concept that brain cancers, such as glioblastoma multiforme (GBM), may originate from cells endowed with stem-like properties. Alterations of the tumour suppressor gene PTEN are very common in primary GBMs. Very recently, PTEN loss was shown to undermine a specific molecular axis, whose failure is associated with the maintenance of the GBM stem cells in mammals. This axis is composed of PTEN, aPKC, and the polarity determinant Lethal giant larvae (Lgl): PTEN loss promotes aPKC activation through the PI3K pathway, which in turn leads to Lgl inhibition, ultimately preventing stem cell differentiation. To find the neural precursors responding to perturbations of this molecular axis, we targeted different neurogenic regions of the Drosophila brain. Here we show that PTEN mutation impacts aPKC and Lgl protein levels also in Drosophila. Moreover, we demonstrate that PI3K activation is not sufficient to trigger tumourigenesis, while aPKC promotes hyperplastic growth of the neuroepithelium and a noticeable expansion of the type II neuroblasts. Finally, we show that these neuroblasts form invasive tumours that persist and keep growing in the adult, leading the affected animals to untimely death, thus displaying frankly malignant behaviours.
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Affiliation(s)
- Simona Paglia
- Department of “Pharmacy and Biotechnology”, University of Bologna, Via Selmi 3, 40126 Bologna, Italy
| | - Manuela Sollazzo
- Department of “Pharmacy and Biotechnology”, University of Bologna, Via Selmi 3, 40126 Bologna, Italy
| | - Simone Di Giacomo
- Department of “Pharmacy and Biotechnology”, University of Bologna, Via Selmi 3, 40126 Bologna, Italy
| | - Dario de Biase
- Department of “Pharmacy and Biotechnology”, University of Bologna, Via Selmi 3, 40126 Bologna, Italy
| | - Annalisa Pession
- Department of “Pharmacy and Biotechnology”, University of Bologna, Via Selmi 3, 40126 Bologna, Italy
| | - Daniela Grifoni
- Department of “Pharmacy and Biotechnology”, University of Bologna, Via Selmi 3, 40126 Bologna, Italy
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22
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Fagegaltier D, Falciatori I, Czech B, Castel S, Perrimon N, Simcox A, Hannon GJ. Oncogenic transformation of Drosophila somatic cells induces a functional piRNA pathway. Genes Dev 2016; 30:1623-35. [PMID: 27474441 PMCID: PMC4973292 DOI: 10.1101/gad.284927.116] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/07/2016] [Indexed: 12/21/2022]
Abstract
Germline genes often become re-expressed in soma-derived human cancers as "cancer/testis antigens" (CTAs), and piRNA (PIWI-interacting RNA) pathway proteins are found among CTAs. However, whether and how the piRNA pathway contributes to oncogenesis in human neoplasms remain poorly understood. We found that oncogenic Ras combined with loss of the Hippo tumor suppressor pathway reactivates a primary piRNA pathway in Drosophila somatic cells coincident with oncogenic transformation. In these cells, Piwi becomes loaded with piRNAs derived from annotated generative loci, which are normally restricted to either the germline or the somatic follicle cells. Negating the pathway leads to increases in the expression of a wide variety of transposons and also altered expression of some protein-coding genes. This correlates with a reduction in the proliferation of the transformed cells in culture, suggesting that, at least in this context, the piRNA pathway may play a functional role in cancer.
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Affiliation(s)
- Delphine Fagegaltier
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Ilaria Falciatori
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge CB2 0RE, United Kingdom
| | - Benjamin Czech
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge CB2 0RE, United Kingdom
| | | | - Norbert Perrimon
- Howard Hughes Medical Institute, Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Amanda Simcox
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Gregory J Hannon
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA; Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge CB2 0RE, United Kingdom; The New York Genome Center, New York, New York 10011, USA
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23
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The Hippo signalling pathway maintains quiescence in Drosophila neural stem cells. Nat Commun 2016; 7:10510. [PMID: 26821647 PMCID: PMC4740179 DOI: 10.1038/ncomms10510] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 12/22/2015] [Indexed: 12/19/2022] Open
Abstract
Stem cells control their mitotic activity to decide whether to proliferate or to stay in quiescence. Drosophila neural stem cells (NSCs) are quiescent at early larval stages, when they are reactivated in response to metabolic changes. Here we report that cell-contact inhibition of growth through the canonical Hippo signalling pathway maintains NSC quiescence. Loss of the core kinases hippo or warts leads to premature nuclear localization of the transcriptional co-activator Yorkie and initiation of growth and proliferation in NSCs. Yorkie is necessary and sufficient for NSC reactivation, growth and proliferation. The Hippo pathway activity is modulated via inter-cellular transmembrane proteins Crumbs and Echinoid that are both expressed in a nutrient-dependent way in niche glial cells and NSCs. Loss of crumbs or echinoid in the niche only is sufficient to reactivate NSCs. Finally, we provide evidence that the Hippo pathway activity discriminates quiescent from non-quiescent NSCs in the Drosophila nervous system. Drosophila neural stem cells (NSCs) are quiescent at early larval stages but how this is regulated is unclear. Here, Ding et al. show that quiescence of NSCs is mediated by cell-contact inhibition via the Hippo pathway transmembrane proteins Crumbs and Echinoid, which in turn are regulated by nutrient levels.
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24
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Yasugi T, Nishimura T. Temporal regulation of the generation of neuronal diversity in Drosophila. Dev Growth Differ 2015; 58:73-87. [PMID: 26690868 DOI: 10.1111/dgd.12245] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/10/2015] [Accepted: 10/10/2015] [Indexed: 12/18/2022]
Abstract
For the construction of complex neural networks, the generation of neurons and glia must be tightly regulated both spatially and temporally. One of the major issues in neural development is the generation of a large variety of neurons and glia over time from a relatively small number of neural stem cells. In Drosophila, neural stem cells, called neuroblasts (NBs), have been used as a useful model system to uncover the molecular and cellular machinery involved in the establishment of neural diversity. NBs divide asymmetrically and produce another self-renewing progenitor cell and a differentiating cell. NBs are subdivided into several types based on their location in the central nervous system. Each type of NB has specific features related to the timing of cell generation, cell cycle progression, temporal patterning for neuronal specification, and termination mechanism. In this review, we focus on the molecular mechanisms that regulate the proliferation of NBs and generate a large variety of neuronal and glia subtypes during development.
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Affiliation(s)
- Tetsuo Yasugi
- Laboratory for Growth Control Signaling, RIKEN Center for Developmental Biology (CDB), 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Takashi Nishimura
- Laboratory for Growth Control Signaling, RIKEN Center for Developmental Biology (CDB), 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
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25
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Gailite I, Aerne BL, Tapon N. Differential control of Yorkie activity by LKB1/AMPK and the Hippo/Warts cascade in the central nervous system. Proc Natl Acad Sci U S A 2015; 112:E5169-78. [PMID: 26324895 PMCID: PMC4577147 DOI: 10.1073/pnas.1505512112] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The Hippo (Hpo) pathway is a highly conserved tumor suppressor network that restricts developmental tissue growth and regulates stem cell proliferation and differentiation. At the heart of the Hpo pathway is the progrowth transcriptional coactivator Yorkie [Yki-Yes-activated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) in mammals]. Yki activity is restricted through phosphorylation by the Hpo/Warts core kinase cascade, but increasing evidence indicates that core kinase-independent modes of regulation also play an important role. Here, we examine Yki regulation in the Drosophila larval central nervous system and uncover a Hpo/Warts-independent function for the tumor suppressor kinase liver kinase B1 (LKB1) and its downstream effector, the energy sensor AMP-activated protein kinase (AMPK), in repressing Yki activity in the central brain/ventral nerve cord. Although the Hpo/Warts core cascade restrains Yki in the optic lobe, it is dispensable for Yki target gene repression in the late larval central brain/ventral nerve cord. Thus, we demonstrate a dramatically different wiring of Hpo signaling in neighboring cell populations of distinct developmental origins in the central nervous system.
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Affiliation(s)
- Ieva Gailite
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, Lincoln's Inn Fields Laboratory, London WC2A 3LY, United Kingdom
| | - Birgit L Aerne
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, Lincoln's Inn Fields Laboratory, London WC2A 3LY, United Kingdom
| | - Nicolas Tapon
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, Lincoln's Inn Fields Laboratory, London WC2A 3LY, United Kingdom
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26
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Kang H, McElroy KA, Jung YL, Alekseyenko AA, Zee BM, Park PJ, Kuroda MI. Sex comb on midleg (Scm) is a functional link between PcG-repressive complexes in Drosophila. Genes Dev 2015; 29:1136-50. [PMID: 26063573 PMCID: PMC4470282 DOI: 10.1101/gad.260562.115] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In this study, Kang et al. investigate how PcG complexes form repressive chromatin domains. The findings show that Scm, a transcriptional repressor, is an important regulator of PRC1, PRC2, and transcriptional silencing and suggest that Scm coordinates PcG complexes and polymerizes, resulting in PcG silencing. The Polycomb group (PcG) proteins are key regulators of development in Drosophila and are strongly implicated in human health and disease. How PcG complexes form repressive chromatin domains remains unclear. Using cross-linked affinity purifications of BioTAP-Polycomb (Pc) or BioTAP-Enhancer of zeste [E(z)], we captured all PcG-repressive complex 1 (PRC1) or PRC2 core components and Sex comb on midleg (Scm) as the only protein strongly enriched with both complexes. Although previously not linked to PRC2, we confirmed direct binding of Scm and PRC2 using recombinant protein expression and colocalization of Scm with PRC1, PRC2, and H3K27me3 in embryos and cultured cells using ChIP-seq (chromatin immunoprecipitation [ChIP] combined with deep sequencing). Furthermore, we found that RNAi knockdown of Scm and overexpression of the dominant-negative Scm-SAM (sterile α motif) domain both affected the binding pattern of E(z) on polytene chromosomes. Aberrant localization of the Scm-SAM domain in long contiguous regions on polytene chromosomes revealed its independent ability to spread on chromatin, consistent with its previously described ability to oligomerize in vitro. Pull-downs of BioTAP-Scm captured PRC1 and PRC2 and additional repressive complexes, including PhoRC, LINT, and CtBP. We propose that Scm is a key mediator connecting PRC1, PRC2, and transcriptional silencing. Combined with previous structural and genetic analyses, our results strongly suggest that Scm coordinates PcG complexes and polymerizes to produce broad domains of PcG silencing.
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Affiliation(s)
- Hyuckjoon Kang
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Kyle A McElroy
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Youngsook Lucy Jung
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Center for Biomedical Informatics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Artyom A Alekseyenko
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Barry M Zee
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Peter J Park
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Center for Biomedical Informatics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Mitzi I Kuroda
- Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA;
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27
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EAG2 potassium channel with evolutionarily conserved function as a brain tumor target. Nat Neurosci 2015; 18:1236-46. [PMID: 26258683 DOI: 10.1038/nn.4088] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 07/15/2015] [Indexed: 12/15/2022]
Abstract
Over 20% of the drugs for treating human diseases target ion channels, but no cancer drug approved by the US Food and Drug Administration (FDA) is intended to target an ion channel. We found that the EAG2 (Ether-a-go-go 2) potassium channel has an evolutionarily conserved function for promoting brain tumor growth and metastasis, delineate downstream pathways, and uncover a mechanism for different potassium channels to functionally cooperate and regulate mitotic cell volume and tumor progression. EAG2 potassium channel was enriched at the trailing edge of migrating medulloblastoma (MB) cells to regulate local cell volume dynamics, thereby facilitating cell motility. We identified the FDA-approved antipsychotic drug thioridazine as an EAG2 channel blocker that reduces xenografted MB growth and metastasis, and present a case report of repurposing thioridazine for treating a human patient. Our findings illustrate the potential of targeting ion channels in cancer treatment.
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Meier K, Brehm A. Chromatin regulation: how complex does it get? Epigenetics 2014; 9:1485-95. [PMID: 25482055 PMCID: PMC4622878 DOI: 10.4161/15592294.2014.971580] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 08/18/2014] [Accepted: 09/29/2014] [Indexed: 12/16/2022] Open
Abstract
Gene transcription is tightly regulated at different levels to ensure that the transcriptome of the cell is appropriate for developmental stage and cell type. The chromatin state in which a gene is embedded determines its expression level to a large extent. Activation or repression of transcription is typically accomplished by the recruitment of chromatin-associated multisubunit protein complexes that combine several molecular tools, such as histone-binding and chromatin-modifying activities. Recent biochemical purifications of such complexes have revealed a substantial diversity. On the one hand, complexes that were thought to be unique have been revealed to be part of large complex families. On the other hand, protein subunits that were thought to only exist in separate complexes have been shown to coexist in novel assemblies. In this review we discuss our current knowledge of repressor complexes that contain MBT domain proteins and/or the CoREST co-repressor and use them as a paradigm to illustrate the unexpected heterogeneity and tool sharing of chromatin regulating protein complexes. These recent insights also challenge the ways we define and think about protein complexes in general.
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Key Words
- ATP, adenosine triphosphate
- BAP, brahma associated protein
- BHC80, BRAF-histone deacetylase complex 80
- BRG1, brahma Related Gene 1
- CHD, chromo domain helicase DNA binding
- CoREST
- CoREST REST, corepressor
- DNA, deoxyribonucleic acid
- DNMT, DNA methyltransferase
- DP-1, dimerization partner 1
- E2F, E2 transcription Factor
- ELM2, EGL-27 and MTA1 homology 2
- ES cell, embryonic stem cells
- H, histone
- HDAC, histone deacetylas
- HMTase, histone methylase
- HP1, heterochromatin protein 1
- K, lysine
- L3MBTL, lethal 3 malignant brain tumor-like
- LINT, l(3)mbt interacting
- LSD1, lysine-specific demethylase 1
- Lint-1, l(3)mbt interacting 1
- MBT protein
- MBT, malignant brain tumor
- MBTS, malignant brain tumor signature
- NPA1, nucleosome assembly protein
- NRSF, neural-restrictive silencing factor
- NuRD, nucleosome remodeling and deacetylase
- PBAP, polybromo-associated BAP
- PHD, plant homeo domain
- PRC1, polycomb repressive complex 1
- PRE, polycomb responsive element
- Pc, polycomb
- PcG, polycomb group
- Ph, polyhomeotic
- Pho, pleiohomeotic
- PhoRC, Pho repressive complex
- Psc, posterior sex combs
- RB, retinoblastoma
- REST, repressor element 1 silencing transcription factor
- RNA, ribonucleic acid
- Rpd3, reduced potassium dependency 3
- SANT, SWI/ADA2/N-CoR/TFIIIB
- SCML, sex combs on midleg-like
- SLC, SFMBT1, LSD1, CoREST
- SWH, Salvador-Warts-Hippo
- SWI/SNF, switching defective/sucrose non-fermenting
- Sce, sex combs extra
- Scm, sex combs on midleg
- Sfmbt, Scm-related gene containing 4 mbt domains
- TSS, transcription start site
- YY1, ying-yang 1
- ZNF, zinc finger
- complex family
- dL(3)mbt, Drosophila Lethal 3 malignant brain tumor
- hBRM, human Brahma
- l(3)mbt, lethal 3 malignant brain tumor
- protein complex
- transcriptional regulation
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Affiliation(s)
- Karin Meier
- Institut für Molekularbiologie und Tumorforschung; Philipps-Universität Marburg; Marburg, Germany
- Instituto de Fisiología Celular; Departamento de Genética Molecular; Universidad Nacional Autónoma de México; México City, México
| | - Alexander Brehm
- Institut für Molekularbiologie und Tumorforschung; Philipps-Universität Marburg; Marburg, Germany
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Schoborg T, Labrador M. Expanding the roles of chromatin insulators in nuclear architecture, chromatin organization and genome function. Cell Mol Life Sci 2014; 71:4089-113. [PMID: 25012699 PMCID: PMC11113341 DOI: 10.1007/s00018-014-1672-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 05/31/2014] [Accepted: 06/23/2014] [Indexed: 01/08/2023]
Abstract
Of the numerous classes of elements involved in modulating eukaryotic chromosome structure and function, chromatin insulators arguably remain the most poorly understood in their contribution to these processes in vivo. Indeed, our view of chromatin insulators has evolved dramatically since their chromatin boundary and enhancer blocking properties were elucidated roughly a quarter of a century ago as a result of recent genome-wide, high-throughput methods better suited to probing the role of these elements in their native genomic contexts. The overall theme that has emerged from these studies is that chromatin insulators function as general facilitators of higher-order chromatin loop structures that exert both physical and functional constraints on the genome. In this review, we summarize the result of recent work that supports this idea as well as a number of other studies linking these elements to a diverse array of nuclear processes, suggesting that chromatin insulators exert master control over genome organization and behavior.
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Affiliation(s)
- Todd Schoborg
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, M407 Walters Life Sciences, 1414 Cumberland Avenue, Knoxville, TN 37996 USA
- Present Address: Laboratory of Molecular Machines and Tissue Architecture, Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, 50 South Dr Rm 2122, Bethesda, MD 20892 USA
| | - Mariano Labrador
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, M407 Walters Life Sciences, 1414 Cumberland Avenue, Knoxville, TN 37996 USA
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Chromatin reader L(3)mbt requires the Myb-MuvB/DREAM transcriptional regulatory complex for chromosomal recruitment. Proc Natl Acad Sci U S A 2014; 111:E4234-43. [PMID: 25249635 DOI: 10.1073/pnas.1416321111] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Lethal malignant brain tumors (lmbt) result from the loss of the conserved transcriptional repressor l(3)mbt, in Drosophila melanogaster. Similar mutations in the human homolog L3MBTL1 correlate with some cancers. The protein's C-terminal MBT repeats bind mono and dimethylated histones in vitro, which could influence recruitment of L3MBTL1 to its target sites. The L(3)mbt chromatin targeting mechanism, however, is controversial and several studies suggest insufficiency or a minor role for histone methylation in determining the site specificity for recruitment. We report that L(3)mbt colocalizes with core members of the Myb-MuvB/DREAM (MMB/DREAM) transcriptional regulatory complex genome-wide, and that L(3)mbt-mediated repression requires this complex in salivary glands and larval brains. Loss of l(3)mbt or of MMB components through mutation cause similar spurious expression of genes, including the transposon regulatory gene piwi, in terminally differentiated cells. The DNA-binding MMB core component Mip120 (Lin54) is required for L(3)mbt recruitment to chromosomes, whereas Mip130 (Lin9) (an MMB core protein) and E2f2 (an MMB transcriptional repressor) are not, but are essential for repression. Cytolocalization experiments suggest the presence of site-specific differential composition of MMB in polytene chromosomes where some loci were bound by a Myb-containing or alternatively, an E2f2 and L(3)mbt form of the complex.
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31
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Drosophila neuroblasts as a new model for the study of stem cell self-renewal and tumour formation. Biosci Rep 2014; 34:BSR20140008. [PMID: 24965943 PMCID: PMC4114065 DOI: 10.1042/bsr20140008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Drosophila larval brain stem cells (neuroblasts) have emerged as an important model for the study of stem cell asymmetric division and the mechanisms underlying the transformation of neural stem cells into tumour-forming cancer stem cells. Each Drosophila neuroblast divides asymmetrically to produce a larger daughter cell that retains neuroblast identity, and a smaller daughter cell that is committed to undergo differentiation. Neuroblast self-renewal and differentiation are tightly controlled by a set of intrinsic factors that regulate ACD (asymmetric cell division). Any disruption of these two processes may deleteriously affect the delicate balance between neuroblast self-renewal and progenitor cell fate specification and differentiation, causing neuroblast overgrowth and ultimately lead to tumour formation in the fly. In this review, we discuss the mechanisms underlying Drosophila neural stem cell self-renewal and differentiation. Furthermore, we highlight emerging evidence in support of the notion that defects in ACD in mammalian systems, which may play significant roles in the series of pathogenic events leading to the development of brain cancers.
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32
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Korenjak M, Kwon E, Morris RT, Anderssen E, Amzallag A, Ramaswamy S, Dyson NJ. dREAM co-operates with insulator-binding proteins and regulates expression at divergently paired genes. Nucleic Acids Res 2014; 42:8939-53. [PMID: 25053843 PMCID: PMC4132727 DOI: 10.1093/nar/gku609] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
dREAM complexes represent the predominant form of E2F/RBF repressor complexes in Drosophila. dREAM associates with thousands of sites in the fly genome but its mechanism of action is unknown. To understand the genomic context in which dREAM acts we examined the distribution and localization of Drosophila E2F and dREAM proteins. Here we report a striking and unexpected overlap between dE2F2/dREAM sites and binding sites for the insulator-binding proteins CP190 and Beaf-32. Genetic assays show that these components functionally co-operate and chromatin immunoprecipitation experiments on mutant animals demonstrate that dE2F2 is important for association of CP190 with chromatin. dE2F2/dREAM binding sites are enriched at divergently transcribed genes, and the majority of genes upregulated by dE2F2 depletion represent the repressed half of a differentially expressed, divergently transcribed pair of genes. Analysis of mutant animals confirms that dREAM and CP190 are similarly required for transcriptional integrity at these gene pairs and suggest that dREAM functions in concert with CP190 to establish boundaries between repressed/activated genes. Consistent with the idea that dREAM co-operates with insulator-binding proteins, genomic regions bound by dREAM possess enhancer-blocking activity that depends on multiple dREAM components. These findings suggest that dREAM functions in the organization of transcriptional domains.
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Affiliation(s)
- Michael Korenjak
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA 02129, USA
| | - Eunjeong Kwon
- Massachusetts General Hospital, Cutaneous Biology Research Center, Charlestown, MA 02129, USA
| | - Robert T Morris
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA 02129, USA
| | - Endre Anderssen
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA 02129, USA
| | - Arnaud Amzallag
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA 02129, USA
| | - Sridhar Ramaswamy
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA 02129, USA
| | - Nicholas J Dyson
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA 02129, USA
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33
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Van Bortle K, Nichols MH, Li L, Ong CT, Takenaka N, Qin ZS, Corces VG. Insulator function and topological domain border strength scale with architectural protein occupancy. Genome Biol 2014; 15:R82. [PMID: 24981874 PMCID: PMC4226948 DOI: 10.1186/gb-2014-15-5-r82] [Citation(s) in RCA: 208] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 06/30/2014] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Chromosome conformation capture studies suggest that eukaryotic genomes are organized into structures called topologically associating domains. The borders of these domains are highly enriched for architectural proteins with characterized roles in insulator function. However, a majority of architectural protein binding sites localize within topological domains, suggesting sites associated with domain borders represent a functionally different subclass of these regulatory elements. How topologically associating domains are established and what differentiates border-associated from non-border architectural protein binding sites remain unanswered questions. RESULTS By mapping the genome-wide target sites for several Drosophila architectural proteins, including previously uncharacterized profiles for TFIIIC and SMC-containing condensin complexes, we uncover an extensive pattern of colocalization in which architectural proteins establish dense clusters at the borders of topological domains. Reporter-based enhancer-blocking insulator activity as well as endogenous domain border strength scale with the occupancy level of architectural protein binding sites, suggesting co-binding by architectural proteins underlies the functional potential of these loci. Analyses in mouse and human stem cells suggest that clustering of architectural proteins is a general feature of genome organization, and conserved architectural protein binding sites may underlie the tissue-invariant nature of topologically associating domains observed in mammals. CONCLUSIONS We identify a spectrum of architectural protein occupancy that scales with the topological structure of chromosomes and the regulatory potential of these elements. Whereas high occupancy architectural protein binding sites associate with robust partitioning of topologically associating domains and robust insulator function, low occupancy sites appear reserved for gene-specific regulation within topological domains.
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Affiliation(s)
- Kevin Van Bortle
- Department of Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Michael H Nichols
- Department of Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Li Li
- Department of Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
- Department of Biostatistics and Bioinformatics, Emory University, Atlanta, GA 30322, USA
| | - Chin-Tong Ong
- Department of Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Naomi Takenaka
- Department of Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Zhaohui S Qin
- Department of Biostatistics and Bioinformatics, Emory University, Atlanta, GA 30322, USA
| | - Victor G Corces
- Department of Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
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34
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Eroglu E, Burkard TR, Jiang Y, Saini N, Homem CCF, Reichert H, Knoblich JA. SWI/SNF complex prevents lineage reversion and induces temporal patterning in neural stem cells. Cell 2014; 156:1259-1273. [PMID: 24630726 DOI: 10.1016/j.cell.2014.01.053] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 11/11/2013] [Accepted: 01/16/2014] [Indexed: 12/22/2022]
Abstract
Members of the SWI/SNF chromatin-remodeling complex are among the most frequently mutated genes in human cancer, but how they suppress tumorigenesis is currently unclear. Here, we use Drosophila neuroblasts to demonstrate that the SWI/SNF component Osa (ARID1) prevents tumorigenesis by ensuring correct lineage progression in stem cell lineages. We show that Osa induces a transcriptional program in the transit-amplifying population that initiates temporal patterning, limits self-renewal, and prevents dedifferentiation. We identify the Prdm protein Hamlet as a key component of this program. Hamlet is directly induced by Osa and regulates the progression of progenitors through distinct transcriptional states to limit the number of transit-amplifying divisions. Our data provide a mechanistic explanation for the widespread tumor suppressor activity of SWI/SNF. Because the Hamlet homologs Evi1 and Prdm16 are frequently mutated in cancer, this mechanism could well be conserved in human stem cell lineages. PAPERCLIP:
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Affiliation(s)
- Elif Eroglu
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Thomas R Burkard
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Yanrui Jiang
- Biozentrum, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Nidhi Saini
- Biozentrum, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Catarina C F Homem
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Heinrich Reichert
- Biozentrum, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Juergen A Knoblich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohr-Gasse 3, 1030 Vienna, Austria.
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35
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Matzat LH, Lei EP. Surviving an identity crisis: a revised view of chromatin insulators in the genomics era. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1839:203-14. [PMID: 24189492 DOI: 10.1016/j.bbagrm.2013.10.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Accepted: 10/10/2013] [Indexed: 10/26/2022]
Abstract
The control of complex, developmentally regulated loci and partitioning of the genome into active and silent domains is in part accomplished through the activity of DNA-protein complexes termed chromatin insulators. Together, the multiple, well-studied classes of insulators in Drosophila melanogaster appear to be generally functionally conserved. In this review, we discuss recent genomic-scale experiments and attempt to reconcile these newer findings in the context of previously defined insulator characteristics based on classical genetic analyses and transgenic approaches. Finally, we discuss the emerging understanding of mechanisms of chromatin insulator regulation. This article is part of a Special Issue entitled: Chromatin and epigenetic regulation of animal development.
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Affiliation(s)
- Leah H Matzat
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Elissa P Lei
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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36
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The microcephaly protein Asp regulates neuroepithelium morphogenesis by controlling the spatial distribution of myosin II. Nat Cell Biol 2013; 15:1294-306. [PMID: 24142104 DOI: 10.1038/ncb2858] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 09/09/2013] [Indexed: 12/16/2022]
Abstract
Mutations in ASPM are the most frequent cause of microcephaly, a disorder characterized by reduced brain size at birth. ASPM is recognized as a major regulator of brain size, yet its role during neural development remains poorly understood. Moreover, the role of ASPM proteins in invertebrate brain morphogenesis has never been investigated. Here, we characterized the function of the Drosophila ASPM orthologue, Asp, and found that asp mutants present severe defects in brain size and neuroepithelium morphogenesis. We show that size reduction depends on the mitotic function of Asp, whereas regulation of tissue shape depends on an uncharacterized function. Asp interacts with myosin II regulating its polarized distribution along the apico-basal axis. In the absence of Asp, mislocalization of myosin II results in interkinetic nuclear migration and tissue architecture defects. We propose that Asp regulates neuroepithelium morphogenesis through myosin-II-mediated structural and mechanical processes to maintain force balance and tissue cohesiveness.
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37
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Morante J, Vallejo DM, Desplan C, Dominguez M. Conserved miR-8/miR-200 defines a glial niche that controls neuroepithelial expansion and neuroblast transition. Dev Cell 2013; 27:174-187. [PMID: 24139822 DOI: 10.1016/j.devcel.2013.09.018] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 07/22/2013] [Accepted: 09/19/2013] [Indexed: 12/12/2022]
Abstract
Neuroepithelial cell proliferation must be carefully balanced with the transition to neuroblast (neural stem cell) to control neurogenesis. Here, we show that loss of the Drosophila microRNA mir-8 (the homolog of vertebrate miR-200 family) results in both excess proliferation and ectopic neuroblast transition. Unexpectedly, mir-8 is expressed in a subpopulation of optic-lobe-associated cortex glia that extend processes that ensheath the neuroepithelium, suggesting that glia cells communicate with the neuroepithelium. We provide evidence that miR-8-positive glia express Spitz, a transforming growth factor α (TGF-α)-like ligand that triggers epidermal growth factor receptor (EGFR) activation to promote neuroepithelial proliferation and neuroblast formation. Further, our experiments suggest that miR-8 ensures both a correct glial architecture and the spatiotemporal control of Spitz protein synthesis via direct binding to Spitz 3' UTR. Together, these results establish glial-derived cues as key regulatory elements in the control of neuroepithelial cell proliferation and the neuroblast transition.
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Affiliation(s)
- Javier Morante
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas y Universidad Miguel Hernández, Av Santiago Ramón y Cajal s/n, 03550 San Juan de Alicante, Spain.
| | - Diana M Vallejo
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas y Universidad Miguel Hernández, Av Santiago Ramón y Cajal s/n, 03550 San Juan de Alicante, Spain
| | - Claude Desplan
- Center for Developmental Genetics, Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
| | - Maria Dominguez
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas y Universidad Miguel Hernández, Av Santiago Ramón y Cajal s/n, 03550 San Juan de Alicante, Spain
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38
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Iovino N, Ciabrelli F, Cavalli G. PRC2 controls Drosophila oocyte cell fate by repressing cell cycle genes. Dev Cell 2013; 26:431-9. [PMID: 23932903 DOI: 10.1016/j.devcel.2013.06.021] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 06/03/2013] [Accepted: 06/19/2013] [Indexed: 01/08/2023]
Abstract
The oocyte is a unique cell type that undergoes extensive chromosome changes on its way to fertilization, but the chromatin determinants of its fate are unknown. Here, we show that Polycomb group (PcG) proteins of the Polycomb repressive complex 2 (PRC2) determine the fate of the oocyte in Drosophila. Mutation of the enzymatic PRC2 subunit Enhancer of zeste (E(z)) in the germline abolishes spatial and temporal control of the cell cycle and induces sterility via transdetermination of the oocyte into a nurse-like cell. This fate switch depends on loss of silencing of two PRC2 target genes, Cyclin E and the cyclin-dependent kinase inhibitor dacapo. By contrast, the PRC1 component Polycomb (Pc) plays no role in this process. Our results demonstrate that PRC2 plays an exquisite role in the determination of the oocyte fate by preventing its switching into an endoreplicative program.
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Affiliation(s)
- Nicola Iovino
- Institut de Génétique Humaine, CNRS, 141 rue de la Cardonille, Montpellier 34396, France
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39
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Soshnev AA, Baxley RM, Manak JR, Tan K, Geyer PK. The insulator protein Suppressor of Hairy-wing is an essential transcriptional repressor in the Drosophila ovary. Development 2013; 140:3613-23. [PMID: 23884443 DOI: 10.1242/dev.094953] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Suppressor of Hairy-wing [Su(Hw)] is a DNA-binding factor required for gypsy insulator function and female germline development in Drosophila. The insulator function of the gypsy retrotransposon depends on Su(Hw) binding to clustered Su(Hw) binding sites (SBSs) and recruitment of the insulator proteins Centrosomal Protein 190 kD (CP190) and Modifier of mdg4 67.2 kD (Mod67.2). By contrast, the Su(Hw) germline function involves binding to non-clustered SBSs and does not require CP190 or Mod67.2. Here, we identify Su(Hw) target genes, using genome-wide analyses in the ovary to uncover genes with an ovary-bound SBS that are misregulated upon Su(Hw) loss. Most Su(Hw) target genes demonstrate enriched expression in the wild-type CNS. Loss of Su(Hw) leads to increased expression of these CNS-enriched target genes in the ovary and other tissues, suggesting that Su(Hw) is a repressor of neural genes in non-neural tissues. Among the Su(Hw) target genes is RNA-binding protein 9 (Rbp9), a member of the ELAV/Hu gene family. Su(Hw) regulation of Rbp9 appears to be insulator independent, as Rbp9 expression is unchanged in a genetic background that compromises the functions of the CP190 and Mod67.2 insulator proteins, even though both localize to Rbp9 SBSs. Rbp9 misregulation is central to su(Hw)(-/-) sterility, as Rbp9(+/-), su(Hw)(-/-) females are fertile. Eggs produced by Rbp9(+/-), su(Hw)(-/-) females show patterning defects, revealing a somatic requirement for Su(Hw) in the ovary. Our studies demonstrate that Su(Hw) is a versatile transcriptional regulatory protein with an essential developmental function involving transcriptional repression.
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Affiliation(s)
- Alexey A Soshnev
- Interdisciplinary Graduate Program in Molecular and Cellular Biology, University of Iowa, Iowa City, IA 52242, USA
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Lim SJ, Boyle PJ, Chinen M, Dale RK, Lei EP. Genome-wide localization of exosome components to active promoters and chromatin insulators in Drosophila. Nucleic Acids Res 2013; 41:2963-80. [PMID: 23358822 PMCID: PMC3597698 DOI: 10.1093/nar/gkt037] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Chromatin insulators are functionally conserved DNA-protein complexes situated throughout the genome that organize independent transcriptional domains. Previous work implicated RNA as an important cofactor in chromatin insulator activity, although the precise mechanisms are not yet understood. Here we identify the exosome, the highly conserved major cellular 3' to 5' RNA degradation machinery, as a physical interactor of CP190-dependent chromatin insulator complexes in Drosophila. Genome-wide profiling of exosome by ChIP-seq in two different embryonic cell lines reveals extensive and specific overlap with the CP190, BEAF-32 and CTCF insulator proteins. Colocalization occurs mainly at promoters but also boundary elements such as Mcp, Fab-8, scs and scs', which overlaps with a promoter. Surprisingly, exosome associates primarily with promoters but not gene bodies of active genes, arguing against simple cotranscriptional recruitment to RNA substrates. Similar to insulator proteins, exosome is also significantly enriched at divergently transcribed promoters. Directed ChIP of exosome in cell lines depleted of insulator proteins shows that CTCF is required specifically for exosome association at Mcp and Fab-8 but not other sites, suggesting that alternate mechanisms must also contribute to exosome chromatin recruitment. Taken together, our results reveal a novel positive relationship between exosome and chromatin insulators throughout the genome.
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Affiliation(s)
- Su Jun Lim
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA
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Kahlert UD, Nikkhah G, Maciaczyk J. Epithelial-to-mesenchymal(-like) transition as a relevant molecular event in malignant gliomas. Cancer Lett 2012; 331:131-8. [PMID: 23268331 DOI: 10.1016/j.canlet.2012.12.010] [Citation(s) in RCA: 179] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 12/10/2012] [Accepted: 12/16/2012] [Indexed: 12/12/2022]
Abstract
Tumor dissemination and metastatic behavior account for the vast majority of cancer associated mortality. Epithelial tumors achieve this progressive state via epithelial-to-mesenchymal transition (EMT); however, the importance of this process in the neuroepithelial context is currently very controversially discussed. The review describes the current research status concerning EMT-like changes in malignant gliomas including the role of TWIST1, ZEB1/ZEB2 and SNAIl1/SNAIl2 as inducers for cell-invasiveness in GBMs. Furthermore, WNT/β-catenin signaling with its key-component FRIZZLED4 activating an EMT-like program in malignant gliomas and its relationship to the stem-like phenotype as well as discoveries on micro-RNA-level regulating the EMT-like process are discussed.
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Affiliation(s)
- U D Kahlert
- Department of General Neurosurgery, Section of Stereotactic Neurosurgery, University Medical Center Freiburg, Germany
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Matzat LH, Dale RK, Moshkovich N, Lei EP. Tissue-specific regulation of chromatin insulator function. PLoS Genet 2012; 8:e1003069. [PMID: 23209434 PMCID: PMC3510032 DOI: 10.1371/journal.pgen.1003069] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 09/20/2012] [Indexed: 11/18/2022] Open
Abstract
Chromatin insulators organize the genome into distinct transcriptional domains and contribute to cell type–specific chromatin organization. However, factors regulating tissue-specific insulator function have not yet been discovered. Here we identify the RNA recognition motif-containing protein Shep as a direct interactor of two individual components of the gypsy insulator complex in Drosophila. Mutation of shep improves gypsy-dependent enhancer blocking, indicating a role as a negative regulator of insulator activity. Unlike ubiquitously expressed core gypsy insulator proteins, Shep is highly expressed in the central nervous system (CNS) with lower expression in other tissues. We developed a novel, quantitative tissue-specific barrier assay to demonstrate that Shep functions as a negative regulator of insulator activity in the CNS but not in muscle tissue. Additionally, mutation of shep alters insulator complex nuclear localization in the CNS but has no effect in other tissues. Consistent with negative regulatory activity, ChIP–seq analysis of Shep in a CNS-derived cell line indicates substantial genome-wide colocalization with a single gypsy insulator component but limited overlap with intact insulator complexes. Taken together, these data reveal a novel, tissue-specific mode of regulation of a chromatin insulator. Mounting evidence in human, mouse, and Drosophila demonstrates a role for the DNA–protein complexes known as chromatin insulators in orchestrating three-dimensional genome organization. Several genes that are only expressed in specific cell types display distinct chromatin configurations correlated with expression status. Recent evidence shows that chromatin insulators play a role in defining tissue-specific chromatin conformation; however, tissue-specific factors that may modulate insulator activity remain unknown. Here we identify a putative RNA–binding protein, Shep, which is expressed most highly in the CNS and interacts directly with insulator complexes. We developed a novel quantitative, tissue-specific insulator assay and found that Shep negatively regulates insulator activity in the CNS. We also find that mutation of shep alters insulator complex nuclear localization in the brain but not other tissues. Finally, we mapped Shep and gypsy insulator protein localization throughout the genome and found that Shep colocalizes with one individual insulator protein but less often than expected with an intact insulator complex. These data suggest that Shep negatively influences insulator activity in a tissue-specific manner.
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Affiliation(s)
- Leah H. Matzat
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ryan K. Dale
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Nellie Moshkovich
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Graduate Program in Molecular and Cell Biology, University of Maryland, College Park, Maryland, United States of America
| | - Elissa P. Lei
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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43
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Bayarmagnai B, Nicolay BN, Islam ABMMK, Lopez-Bigas N, Frolov MV. Drosophila GAGA factor is required for full activation of the dE2f1-Yki/Sd transcriptional program. Cell Cycle 2012; 11:4191-202. [PMID: 23070566 DOI: 10.4161/cc.22486] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The Hippo signaling pathway regulates organ size by controlling the activity of the transcriptional co-activator Yorkie (Yki). Yki is recruited to its target genes by DNA-binding proteins such as Scalloped (Sd). In addition, transcription factor dE2f1, of the Retinoblastoma (Rb) pathway, cooperates with Yki/Sd to synergistically activate a set of common cell cycle target genes. However, little is known about other factors that ensure the proper transcriptional output of Hippo signaling. In this report we identified the chromatin protein GAGA factor (GAF), which is encoded by the Trithorax-like (Trl) gene, as a novel and critical partner in transcriptional regulation by Yki/Sd and dE2f1. We show that GAF is required for the full activation of target genes by dE2f1 and Yki/Sd; while ablation of GAF compromises both normal and inappropriate cell proliferation driven by Yki and dE2f1 in multiple tissues. The importance of GAF is further supported by strong genetic interactions between GAF and the Rb and Hippo pathways. Additionally, we show that GAF directly interacts with RBF, a Drosophila pRB homolog, and partially co-localizes with RBF on polytene chromosomes. Collectively, our data provide a novel connection between a chromatin-binding protein and a transcriptional program governed by the Hippo and Rb pathways.
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Affiliation(s)
- Battuya Bayarmagnai
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA
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Abstract
Germline stem cells are key to genome transmission to future generations. Over recent years, there have been numerous insights into the regulatory mechanisms that govern both germ cell specification and the maintenance of the germline in adults. Complex regulatory interactions with both the niche and the environment modulate germline stem cell function. This perspective highlights some examples of this regulation to illustrate the diversity and complexity of the mechanisms involved.
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Affiliation(s)
- Ruth Lehmann
- Howard Hughes Medical Institute; Skirball Institute, The Helen L. and Martin S. Kimmel Center for Stem Cell Biology, Department of Cell Biology, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA.
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Sakaguchi A, Joyce E, Aoki T, Schedl P, Steward R. The histone H4 lysine 20 monomethyl mark, set by PR-Set7 and stabilized by L(3)mbt, is necessary for proper interphase chromatin organization. PLoS One 2012; 7:e45321. [PMID: 23024815 PMCID: PMC3443217 DOI: 10.1371/journal.pone.0045321] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 08/21/2012] [Indexed: 11/28/2022] Open
Abstract
Drosophila PR-Set7 or SET8 is a histone methyltransferase that specifically monomethylates histone H4 lysine 20 (H4K20). L(3)MBT has been identified as a reader of methylated H4K20. It contains several conserved domains including three MBT repeats binding mono- and dimethylated H4K20 peptides. We find that the depletion of PR-Set7 blocks de novo H4K20me1 resulting in the immediate activation of the DNA damage checkpoint, an increase in the size of interphase nuclei, and drastic reduction of cell viability. L(3)mbt on the other hand stabilizes the monomethyl mark, as L(3)mbt-depleted S2 cells show a reduction of more than 60% of bulk monomethylated H4K20 (H4K20me1) while viability is barely affected. Ploidy and basic chromatin structure show only small changes in PR-Set7-depleted cells, but higher order interphase chromatin organization is significantly affected presumably resulting in the activation of the DNA damage checkpoint. In the absence of any other known functions of PR-Set7, the setting of the de novo monomethyl mark appears essential for cell viability in the presence or absence of the DNA damage checkpoint, but once newly assembled chromatin is established the monomethyl mark, protected by L(3)mbt, is dispensable.
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Affiliation(s)
- Ayako Sakaguchi
- Waksman Institute, Cancer Institute of New Jersey, Rutgers University, Piscataway, New Jersey, United States of America
| | - Eric Joyce
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Tsutomu Aoki
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Paul Schedl
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Ruth Steward
- Waksman Institute, Cancer Institute of New Jersey, Rutgers University, Piscataway, New Jersey, United States of America
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey, United States of America
- * E-mail:
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Nady N, Krichevsky L, Zhong N, Duan S, Tempel W, Amaya MF, Ravichandran M, Arrowsmith CH. Histone recognition by human malignant brain tumor domains. J Mol Biol 2012; 423:702-18. [PMID: 22954662 DOI: 10.1016/j.jmb.2012.08.022] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 08/27/2012] [Accepted: 08/27/2012] [Indexed: 10/27/2022]
Abstract
Histone methylation has emerged as an important covalent modification involved in a variety of biological processes, especially regulation of transcription and chromatin dynamics. Lysine methylation is found in three distinct states (monomethylation, dimethylation and trimethylation), which are recognized by specific protein domains. The malignant brain tumor (MBT) domain is one such module found in several chromatin regulatory complexes including Polycomb repressive complex 1. Here, we present a comprehensive characterization of the human MBT family with emphasis on histone binding specificity. SPOT-blot peptide arrays were used to screen for the methyllysine-containing histone peptides that bind to MBT domains found in nine human proteins. Selected interactions were quantified using fluorescence polarization assays. We show that all MBT proteins recognize only monomethyllysine and/or dimethyllysine marks and provide evidence that some MBT domains recognize a defined consensus sequence while others bind in a promiscuous, non-sequence-specific manner. Furthermore, using structure-based mutants, we identify a triad of residues in the methyllysine binding pocket that imparts discrimination between monomethyllysine and dimethyllysine. This study represents a comprehensive analysis of MBT substrate specificity, establishing a foundation for the rational design of selective MBT domain inhibitors that may enable elucidation of their role in human biology and disease.
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Affiliation(s)
- Nataliya Nady
- Ontario Cancer Institute, Campbell Family Cancer Research Institute and Department of Medical Biophysics, University of Toronto, 101 College Street, Toronto, ON, Canada M5G 1L7
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Chen KF, Crowther DC. Functional genomics in Drosophila models of human disease. Brief Funct Genomics 2012; 11:405-15. [PMID: 22914042 DOI: 10.1093/bfgp/els038] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
It is occasionally observed that common sporadic diseases have rare familial counterparts in which mutations at a single locus result in a similar disorder exhibiting simple Mendelian inheritance. Such an observation is often sufficient justification for the creation of a disease model in the fly. Whether the system is based on the over-expression of a toxic variant of a human protein or requires the loss of function of an orthologous fly gene, the consequent phenotypes can be used to understand pathogenesis through the discovery of genetic modifiers. Such genetic screening can be completed rapidly in the fly and in this review we outline how libraries of mutants are generated and how consequent changes in disease-related phenotypes are assessed. The bioinformatic approaches to processing the copious amounts of data so generated are also presented. The next phase of fly modelling will tackle the challenges of complex diseases in which many genes are associated with risk in the human. There is growing interest in the use of interactomics and epigenetics to provide proteome- and genome-scale descriptions of the regulatory dysfunction that results in disease.
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Affiliation(s)
- Ko-Fan Chen
- Department of Genetics, University of Cambridge, Cambridge, UK
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48
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Abstract
Long-range interactions between transcription regulatory elements play an important role in gene activation, epigenetic silencing, and chromatin organization. Transcriptional activation or repression of developmentally regulated genes is often accomplished through tissue-specific chromatin architecture and dynamic localization between active transcription factories and repressive Polycomb bodies. However, the mechanisms underlying the structural organization of chromatin and the coordination of physical interactions are not fully understood. Insulators and Polycomb group proteins form highly conserved multiprotein complexes that mediate functional long-range interactions and have proposed roles in nuclear organization. In this review, we explore recent findings that have broadened our understanding of the function of these proteins and provide an integrative model for the roles of insulators in nuclear organization.
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Affiliation(s)
- Kevin Van Bortle
- Department of Biology, Emory University, Atlanta, Georgia 30322, USA
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The BEAF insulator regulates genes involved in cell polarity and neoplastic growth. Dev Biol 2012; 369:124-32. [PMID: 22743648 DOI: 10.1016/j.ydbio.2012.06.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 06/01/2012] [Accepted: 06/20/2012] [Indexed: 01/05/2023]
Abstract
Boundary Element Associated Factor-32 (BEAF-32) is an insulator protein predominantly found near gene promoters and thought to play a role in gene expression. We find that mutations in BEAF-32 are lethal, show loss of epithelial morphology in imaginal discs and cause neoplastic growth defects. To investigate the molecular mechanisms underlying this phenotype, we carried out a genome-wide analysis of BEAF-32 localization in wing imaginal disc cells. Mutation of BEAF-32 results in miss-regulation of 3850 genes by at least 1.5-fold, 794 of which are bound by this protein in wing imaginal cells. Up-regulated genes encode proteins involved in cell polarity, cell proliferation and cell differentiation. Among the down-regulated genes are those encoding components of the wingless pathway, which is required for cell differentiation. Miss-regulation of these genes explains the unregulated cell growth and neoplastic phenotypes observed in imaginal tissues of BEAF-32 mutants.
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Van Bortle K, Ramos E, Takenaka N, Yang J, Wahi JE, Corces VG. Drosophila CTCF tandemly aligns with other insulator proteins at the borders of H3K27me3 domains. Genome Res 2012; 22:2176-87. [PMID: 22722341 PMCID: PMC3483547 DOI: 10.1101/gr.136788.111] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Several multiprotein DNA complexes capable of insulator activity have been identified in Drosophila melanogaster, yet only CTCF, a highly conserved zinc finger protein, and the transcription factor TFIIIC have been shown to function in mammals. CTCF is involved in diverse nuclear activities, and recent studies suggest that the proteins with which it associates and the DNA sequences that it targets may underlie these various roles. Here we show that the Drosophila homolog of CTCF (dCTCF) aligns in the genome with other Drosophila insulator proteins such as Suppressor of Hairy wing [SU(HW)] and Boundary Element Associated Factor of 32 kDa (BEAF-32) at the borders of H3K27me3 domains, which are also enriched for associated insulator proteins and additional cofactors. RNAi depletion of dCTCF and combinatorial knockdown of gene expression for other Drosophila insulator proteins leads to a reduction in H3K27me3 levels within repressed domains, suggesting that insulators are important for the maintenance of appropriate repressive chromatin structure in Polycomb (Pc) domains. These results shed new insights into the roles of insulators in chromatin domain organization and support recent models suggesting that insulators underlie interactions important for Pc-mediated repression. We reveal an important relationship between dCTCF and other Drosophila insulator proteins and speculate that vertebrate CTCF may also align with other nuclear proteins to accomplish similar functions.
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