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Kashiwagi K, Yoshida J, Kimura H, Shinjo K, Kondo Y, Horie K. Mutation of the SWI/SNF complex component Smarce1 decreases nucleosome stability in embryonic stem cells and impairs differentiation. J Cell Sci 2024; 137:jcs260467. [PMID: 38357971 DOI: 10.1242/jcs.260467] [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: 07/28/2022] [Accepted: 02/07/2024] [Indexed: 02/16/2024] Open
Abstract
The SWI/SNF chromatin remodeling complex consists of more than ten component proteins that form a large protein complex of >1 MDa. The catalytic proteins Smarca4 or Smarca2 work in concert with the component proteins to form a chromatin platform suitable for transcriptional regulation. However, the mechanism by which each component protein works synergistically with the catalytic proteins remains largely unknown. Here, we report on the function of Smarce1, a component of the SWI/SNF complex, through the phenotypic analysis of homozygous mutant embryonic stem cells (ESCs). Disruption of Smarce1 induced the dissociation of other complex components from the SWI/SNF complex. Histone binding to DNA was loosened in homozygous mutant ESCs, indicating that disruption of Smarce1 decreased nucleosome stability. Sucrose gradient sedimentation analysis suggested that there was an ectopic genomic distribution of the SWI/SNF complex upon disruption of Smarce1, accounting for the misregulation of chromatin conformations. Unstable nucleosomes remained during ESC differentiation, impairing the heterochromatin formation that is characteristic of the differentiation process. These results suggest that Smarce1 guides the SWI/SNF complex to the appropriate genomic regions to generate chromatin structures adequate for transcriptional regulation.
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Affiliation(s)
- Katsunobu Kashiwagi
- Department of Physiology II, Nara Medical University, Kashihara, Nara 634-8521, Japan
- Division of Cancer Biology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Junko Yoshida
- Department of Physiology II, Nara Medical University, Kashihara, Nara 634-8521, Japan
| | - Hiroshi Kimura
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8503, Japan
| | - Keiko Shinjo
- Division of Cancer Biology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Yutaka Kondo
- Division of Cancer Biology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Kyoji Horie
- Department of Physiology II, Nara Medical University, Kashihara, Nara 634-8521, Japan
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2
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Hernández-García J, Diego-Martin B, Kuo PH, Jami-Alahmadi Y, Vashisht AA, Wohlschlegel J, Jacobsen SE, Blázquez MA, Gallego-Bartolomé J. Comprehensive identification of SWI/SNF complex subunits underpins deep eukaryotic ancestry and reveals new plant components. Commun Biol 2022; 5:549. [PMID: 35668117 PMCID: PMC9170682 DOI: 10.1038/s42003-022-03490-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 05/16/2022] [Indexed: 01/19/2023] Open
Abstract
Over millions of years, eukaryotes evolved from unicellular to multicellular organisms with increasingly complex genomes and sophisticated gene expression networks. Consequently, chromatin regulators evolved to support this increased complexity. The ATP-dependent chromatin remodelers of the SWI/SNF family are multiprotein complexes that modulate nucleosome positioning and appear under different configurations, which perform distinct functions. While the composition, architecture, and activity of these subclasses are well understood in a limited number of fungal and animal model organisms, the lack of comprehensive information in other eukaryotic organisms precludes the identification of a reliable evolutionary model of SWI/SNF complexes. Here, we performed a systematic analysis using 36 species from animal, fungal, and plant lineages to assess the conservation of known SWI/SNF subunits across eukaryotes. We identified evolutionary relationships that allowed us to propose the composition of a hypothetical ancestral SWI/SNF complex in the last eukaryotic common ancestor. This last common ancestor appears to have undergone several rounds of lineage-specific subunit gains and losses, shaping the current conformation of the known subclasses in animals and fungi. In addition, our results unravel a plant SWI/SNF complex, reminiscent of the animal BAF subclass, which incorporates a set of plant-specific subunits of still unknown function.
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Affiliation(s)
- Jorge Hernández-García
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-Universitat Politècnica de València, Valencia, 46022, Spain
- Laboratory of Biochemistry, Wageningen University & Research, 6703 WE, Stippeneng 4, Wageningen, The Netherlands
| | - Borja Diego-Martin
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-Universitat Politècnica de València, Valencia, 46022, Spain
| | - Peggy Hsuanyu Kuo
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, 90095, CA, USA
| | - Yasaman Jami-Alahmadi
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, 90095, CA, USA
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, 90095, CA, USA
| | - Ajay A Vashisht
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, 90095, CA, USA
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, 90095, CA, USA
| | - James Wohlschlegel
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, 90095, CA, USA
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, 90095, CA, USA
| | - Steven E Jacobsen
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, 90095, CA, USA
- Eli & Edythe Broad Center of Regenerative Medicine & Stem Cell Research, University of California at Los Angeles, Los Angeles, 90095, CA, USA
- Howard Hughes Medical Institute, University of California at Los Angeles, Los Angeles, 90095, CA, USA
| | - Miguel A Blázquez
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-Universitat Politècnica de València, Valencia, 46022, Spain
| | - Javier Gallego-Bartolomé
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-Universitat Politècnica de València, Valencia, 46022, Spain.
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Ingham VA, Elg S, Nagi SC, Dondelinger F. Capturing the transcription factor interactome in response to sub-lethal insecticide exposure. CURRENT RESEARCH IN INSECT SCIENCE 2021; 1:None. [PMID: 34977825 PMCID: PMC8702396 DOI: 10.1016/j.cris.2021.100018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 06/15/2021] [Accepted: 07/21/2021] [Indexed: 12/02/2022]
Abstract
The increasing levels of pesticide resistance in agricultural pests and disease vectors represents a threat to both food security and global health. As insecticide resistance intensity strengthens and spreads, the likelihood of a pest encountering a sub-lethal dose of pesticide dramatically increases. Here, we apply dynamic Bayesian networks to a transcriptome time-course generated using sub-lethal pyrethroid exposure on a highly resistant Anopheles coluzzii population. The model accounts for circadian rhythm and ageing effects allowing high confidence identification of transcription factors with key roles in pesticide response. The associations generated by this model show high concordance with lab-based validation and identifies 44 transcription factors putatively regulating insecticide-responsive transcripts. We identify six key regulators, with each displaying differing enrichment terms, demonstrating the complexity of pesticide response. The considerable overlap of resistance mechanisms in agricultural pests and disease vectors strongly suggests that these findings are relevant in a wide variety of pest species.
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Innis SM, Cabot B. GBAF, a small BAF sub-complex with big implications: a systematic review. Epigenetics Chromatin 2020; 13:48. [PMID: 33143733 PMCID: PMC7607862 DOI: 10.1186/s13072-020-00370-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 10/23/2020] [Indexed: 12/01/2022] Open
Abstract
ATP-dependent chromatin remodeling by histone-modifying enzymes and chromatin remodeling complexes is crucial for maintaining chromatin organization and facilitating gene transcription. In the SWI/SNF family of ATP-dependent chromatin remodelers, distinct complexes such as BAF, PBAF, GBAF, esBAF and npBAF/nBAF are of particular interest regarding their implications in cellular differentiation and development, as well as in various diseases. The recently identified BAF subcomplex GBAF is no exception to this, and information is emerging linking this complex and its components to crucial events in mammalian development. Furthermore, given the essential nature of many of its subunits in maintaining effective chromatin remodeling function, it comes as no surprise that aberrant expression of GBAF complex components is associated with disease development, including neurodevelopmental disorders and numerous malignancies. It becomes clear that building upon our knowledge of GBAF and BAF complex function will be essential for advancements in both mammalian reproductive applications and the development of more effective therapeutic interventions and strategies. Here, we review the roles of the SWI/SNF chromatin remodeling subcomplex GBAF and its subunits in mammalian development and disease.
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Affiliation(s)
- Sarah M Innis
- Department of Animal Sciences, Purdue University, West Lafayette, IN, USA
| | - Birgit Cabot
- Department of Animal Sciences, Purdue University, West Lafayette, IN, USA.
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5
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Alfert A, Moreno N, Kerl K. The BAF complex in development and disease. Epigenetics Chromatin 2019; 12:19. [PMID: 30898143 PMCID: PMC6427853 DOI: 10.1186/s13072-019-0264-y] [Citation(s) in RCA: 150] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/13/2019] [Indexed: 01/16/2023] Open
Abstract
The ATP-dependent chromatin remodelling complex BAF (= mammalian SWI/SNF complex) is crucial for the regulation of gene expression and differentiation. In the course of evolution from yeast to mammals, the BAF complex evolved an immense complexity with a high number of subunits encoded by gene families. In this way, tissue-specific BAF function and regulation of development begin with the combinatorial assembly of distinct BAF complexes such as esBAF, npBAF and nBAF. Furthermore, whole-genome sequencing reveals the tremendous role BAF complex mutations have in both neurodevelopmental disorders and human malignancies. Therefore, gaining a more elaborate insight into how BAF complex assembly influences its function and which role distinct subunits play, will hopefully give rise to a better understanding of disease pathogenesis and ultimately to new treatments for many human diseases.
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Affiliation(s)
- Amelie Alfert
- Department of Paediatric Haematology and Oncology, University Children’s Hospital Muenster, Domagkstraße 24, 48149 Muenster, Germany
| | - Natalia Moreno
- Department of Paediatric Haematology and Oncology, University Children’s Hospital Muenster, Domagkstraße 24, 48149 Muenster, Germany
| | - Kornelius Kerl
- Department of Paediatric Haematology and Oncology, University Children’s Hospital Muenster, Domagkstraße 24, 48149 Muenster, Germany
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7
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Endler L, Gibert J, Nolte V, Schlötterer C. Pleiotropic effects of regulatory variation in tan result in correlation of two pigmentation traits in Drosophila melanogaster. Mol Ecol 2018; 27:3207-3218. [PMID: 29957826 PMCID: PMC6120501 DOI: 10.1111/mec.14781] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 05/24/2018] [Accepted: 06/25/2018] [Indexed: 01/10/2023]
Abstract
Traits with a common genetic basis frequently display correlated phenotypic responses to selection or environmental conditions. In Drosophila melanogaster, pigmentation of the abdomen and a trident-shaped region on the thorax are genetically correlated. Here, we used a pooled replicated genomewide association approach (Pool-GWAS) to identify the genetic basis of variation in thoracic trident pigmentation in two Drosophila melanogaster populations. We confirmed the previously reported large effect of ebony and the association of the cosmopolitan inversion In(3R)Payne. For the first time, we identified tan as another major locus contributing to variation in trident pigmentation. Intriguingly, the regulatory variants of tan that were most strongly associated with female abdominal pigmentation also showed a strong association with trident pigmentation. We validated this common genetic basis in transgenic assays and found qualitatively similar effects on trident and abdominal pigmentation. Further work is required to determine whether this genetic correlation is favoured by natural selection or reflects a neutral by-product of a shared regulatory architecture.
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Affiliation(s)
- Lukas Endler
- Institute of PopulationsgenetikVetmeduni WienWienAustria
| | - Jean‐Michel Gibert
- CNRSBiologie du Développement Paris Seine‐Institut de Biologie Paris Seine (LBD‐IBPS)Sorbonne UniversitéParisFrance
| | - Viola Nolte
- Institute of PopulationsgenetikVetmeduni WienWienAustria
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8
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Morimoto M, Choi K, Boerkoel CF, Cho KS. Chromatin changes in SMARCAL1 deficiency: A hypothesis for the gene expression alterations of Schimke immuno-osseous dysplasia. Nucleus 2017; 7:560-571. [PMID: 27813696 DOI: 10.1080/19491034.2016.1255835] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mutations in SMARCAL1, which encodes a DNA annealing helicase with roles in DNA replication fork restart, DNA repair, and gene expression modulation, cause Schimke immuno-osseous dysplasia (SIOD), an autosomal recessive disease characterized by skeletal dysplasia, renal disease, T-cell immunodeficiency, and arteriosclerosis. The clinical features of SIOD arise from pathological changes in gene expression; however, the underlying mechanism for these gene expression alterations remains unclear. We hypothesized that changes of the epigenome alter gene expression in SIOD. To test this, we performed a genetic screen for interaction between Marcal1, the Drosophila melanogaster ortholog of SMARCAL1, and the genes of the trithorax group (trxG) and Polycomb group (PcG), which encode epigenetic regulators. SMARCAL1 and Marcal1 genetically interacted with trxG and PcG members. A homozygous null mutation of Marcal1 suppressed the wing-to-haltere transformation, ectopic Ultrabithorax (Ubx) expression, and ectopic Ubx minigene expression caused by PcG deficiency. The suppression of ectopic Ubx expression correlated with reduced chromatin accessibility of the Ubx promoter. To our knowledge, this is the first in vivo evidence for deficiency of a SMARCAL1 ortholog altering the chromatin structure of a gene.
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Affiliation(s)
- Marie Morimoto
- a Department of Medical Genetics , University of British Columbia , Vancouver , BC , Canada
| | - Kunho Choi
- a Department of Medical Genetics , University of British Columbia , Vancouver , BC , Canada
| | - Cornelius F Boerkoel
- a Department of Medical Genetics , University of British Columbia , Vancouver , BC , Canada
| | - Kyoung Sang Cho
- b Department of Biological Sciences , Konkuk University , Seoul , Republic of Korea
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9
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Silva APG, Ryan DP, Galanty Y, Low JKK, Vandevenne M, Jackson SP, Mackay JP. The N-terminal Region of Chromodomain Helicase DNA-binding Protein 4 (CHD4) Is Essential for Activity and Contains a High Mobility Group (HMG) Box-like-domain That Can Bind Poly(ADP-ribose). J Biol Chem 2016; 291:924-38. [PMID: 26565020 PMCID: PMC4705410 DOI: 10.1074/jbc.m115.683227] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 11/09/2015] [Indexed: 01/11/2023] Open
Abstract
Chromodomain Helicase DNA-binding protein 4 (CHD4) is a chromatin-remodeling enzyme that has been reported to regulate DNA-damage responses through its N-terminal region in a poly(ADP-ribose) polymerase-dependent manner. We have identified and determined the structure of a stable domain (CHD4-N) in this N-terminal region. The-fold consists of a four-α-helix bundle with structural similarity to the high mobility group box, a domain that is well known as a DNA binding module. We show that the CHD4-N domain binds with higher affinity to poly(ADP-ribose) than to DNA. We also show that the N-terminal region of CHD4, although not CHD4-N alone, is essential for full nucleosome remodeling activity and is important for localizing CHD4 to sites of DNA damage. Overall, these data build on our understanding of how CHD4-NuRD acts to regulate gene expression and participates in the DNA-damage response.
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Affiliation(s)
- Ana P G Silva
- From the School of Molecular Bioscience, The University of Sydney, New South Wales 2006, Australia,
| | - Daniel P Ryan
- Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory 2601, and
| | - Yaron Galanty
- The Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, United Kingdom
| | - Jason K K Low
- From the School of Molecular Bioscience, The University of Sydney, New South Wales 2006, Australia
| | - Marylene Vandevenne
- From the School of Molecular Bioscience, The University of Sydney, New South Wales 2006, Australia
| | - Stephen P Jackson
- The Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, United Kingdom
| | - Joel P Mackay
- From the School of Molecular Bioscience, The University of Sydney, New South Wales 2006, Australia,
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10
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Kadoch C, Crabtree GR. Mammalian SWI/SNF chromatin remodeling complexes and cancer: Mechanistic insights gained from human genomics. SCIENCE ADVANCES 2015; 1:e1500447. [PMID: 26601204 PMCID: PMC4640607 DOI: 10.1126/sciadv.1500447] [Citation(s) in RCA: 578] [Impact Index Per Article: 64.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 04/26/2015] [Indexed: 05/25/2023]
Abstract
Over the past 4 years, nearly 100 exome sequencing studies have revealed the high frequency of mutations in the genes encoding the subunits of ATP-dependent chromatin remodelers in human cancer. Most of these mutations are within the genes encoding subunits of the BAF (Brg/Brahma-associated factors) or mSWI/SNF complex, which is one of two dozen predicted ATP-dependent chromatin remodeling complexes in mammals. Considering BAF complexes as a single entity, the 15 subunits encoded by 29 genes are mutated in >20% of human cancer, across a broad range of tumor types. These observations demonstrate that there is little redundancy in the oncogenic function of BAF complexes with the other remodeling complexes, underscoring their unique roles. Several important conclusions emerge from these genomic data: specific subunits appear to be mutated in specific cancers, highlighting tissue-specific protective roles; mutations can function as tumor suppressors or oncogenes; mutations can be homozygous or, more commonly, heterozygous, implying their dosage-sensitive roles in an unknown yet fundamental process used to suppress the genesis of cancer. These new human genetic findings paired with biochemical studies are challenging old ideas on how chromatin remodeling complexes function, generating new hypotheses with respect to their normal and oncogenic mechanisms and highlighting potential avenues for therapeutic intervention in human cancer.
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Affiliation(s)
- Cigall Kadoch
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02215, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Gerald R. Crabtree
- Howard Hughes Medical Institute, Departments of Pathology and Developmental Biology, Stanford University, Stanford, CA 94305, USA
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11
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Fischer B, Sandmann T, Horn T, Billmann M, Chaudhary V, Huber W, Boutros M. A map of directional genetic interactions in a metazoan cell. eLife 2015; 4. [PMID: 25748138 PMCID: PMC4384530 DOI: 10.7554/elife.05464] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 02/28/2015] [Indexed: 12/12/2022] Open
Abstract
Gene–gene interactions shape complex phenotypes and modify the effects of mutations during development and disease. The effects of statistical gene–gene interactions on phenotypes have been used to assign genes to functional modules. However, directional, epistatic interactions, which reflect regulatory relationships between genes, have been challenging to map at large-scale. Here, we used combinatorial RNA interference and automated single-cell phenotyping to generate a large genetic interaction map for 21 phenotypic features of Drosophila cells. We devised a method that combines genetic interactions on multiple phenotypes to reveal directional relationships. This network reconstructed the sequence of protein activities in mitosis. Moreover, it revealed that the Ras pathway interacts with the SWI/SNF chromatin-remodelling complex, an interaction that we show is conserved in human cancer cells. Our study presents a powerful approach for reconstructing directional regulatory networks and provides a resource for the interpretation of functional consequences of genetic alterations. DOI:http://dx.doi.org/10.7554/eLife.05464.001 Genes encode instructions that control our physical characteristics, known as traits. Although some traits are controlled by the activity of a single gene, most traits are influenced by the activities of multiple genes. The genes that influence a particular trait may work independently of each other. However, it is also possible for the genes to interact so that one gene may mask or amplify the effect of another gene. Although gene interactions were first described almost 100 years ago, it has been difficult to identify them and work out the direction of these interactions (i.e., does gene A affect gene B, or vice versa?). Fischer, Sandmann et al. have now studied the interactions between the genes involved in 21 different traits of fruit fly cells. A technique called RNA interference was used to lower the expression of the genes in different combinations, which made it possible to analyze any changes in the traits that occurred when particular genes were not working properly. Fischer, Sandmann et al. took hundreds of thousands images of the cells and analyzed the changes in cell shape, cell size, cell division and other traits. Next, they developed a method to infer the directions of the interactions between individual pairs of genes from the data and then made a map of the genetic interactions for the traits. This map was able to reconstruct the known order of activity of genes during cell division and other cell processes. Furthermore, it revealed previously unknown interactions between genes. For example, genes involved in the Ras signaling pathway—which promotes cell growth and is frequently mutated in human tumors—interacted with genes that encode a group of proteins called the SWI/SNF complex. This complex alters how DNA is packaged in cells to control the expression of genes, and these gene interactions may play an important role in the control of cell growth by Ras signaling. The approach developed by Fischer, Sandmann et al. can shed light on the interactions between genes that produce complex traits of cells. In future, this approach might be helpful to find out which genetic differences between individuals alter the effectiveness of drug treatments, and the impact of using combinations of drugs to treat diseases. DOI:http://dx.doi.org/10.7554/eLife.05464.002
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Affiliation(s)
- Bernd Fischer
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Thomas Sandmann
- Division of Signaling and Functional Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Thomas Horn
- Division of Signaling and Functional Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Maximilian Billmann
- Division of Signaling and Functional Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Varun Chaudhary
- Division of Signaling and Functional Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Wolfgang Huber
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Michael Boutros
- Division of Signaling and Functional Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
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12
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Hepp MI, Alarcon V, Dutta A, Workman JL, Gutiérrez JL. Nucleosome remodeling by the SWI/SNF complex is enhanced by yeast high mobility group box (HMGB) proteins. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1839:764-72. [PMID: 24972368 DOI: 10.1016/j.bbagrm.2014.06.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 06/16/2014] [Accepted: 06/18/2014] [Indexed: 12/01/2022]
Abstract
The regulation of gene expression at the level of transcription involves the concerted action of several proteins and protein complexes committed to dynamically alter the surrounding chromatin environment of a gene being activated or repressed. ATP-dependent chromatin remodeling complexes are key factors in chromatin remodeling, and the SWI/SNF complex is the founding member. While many studies have linked the action of these complexes to specific transcriptional regulation of a large number of genes and much is known about their catalytic activity, less is known about the nuclear elements that can enhance or modulate their activity. A number of studies have found that certain High Mobility Group (HMG) proteins are able to stimulate ATP-dependent chromatin remodeling activity, but their influence on the different biochemical outcomes of this activity is still unknown. In this work we studied the influence of the yeast Nhp6A, Nhp6B and Hmo1 proteins (HMGB family members) on different biochemical outcomes of yeast SWI/SNF remodeling activity. We found that all these HMG proteins stimulate the sliding activity of ySWI/SNF, while transient exposure of nucleosomal DNA and octamer transfer catalyzed by this complex are only stimulated by Hmo1. Consistently, only Hmo1 stimulates SWI/SNF binding to the nucleosome. Additionally, the sliding activity of another chromatin remodeling complex, ISW1a, is only stimulated by Hmo1. Further analyses show that these differential stimulatory effects of Hmo1 are dependent on the presence of its C-terminal tail, which contains a stretch of acidic and basic residues.
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Affiliation(s)
- Matias I Hepp
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, Concepción 4070043, Chile
| | - Valentina Alarcon
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, Concepción 4070043, Chile
| | - Arnob Dutta
- Stowers Institute for Medical Research, 1000 E 50th Street, Kansas City 64110, MO, USA
| | - Jerry L Workman
- Stowers Institute for Medical Research, 1000 E 50th Street, Kansas City 64110, MO, USA
| | - José L Gutiérrez
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, Concepción 4070043, Chile.
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13
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Caenorhabditis elegans SWI/SNF subunits control sequential developmental stages in the somatic gonad. G3-GENES GENOMES GENETICS 2014; 4:471-83. [PMID: 24402584 PMCID: PMC3962486 DOI: 10.1534/g3.113.009852] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The Caenorhabditis elegans somatic gonadal precursors (SGPs) are multipotent progenitors that give rise to all somatic tissues of the adult reproductive system. The hunchback and Ikaros-like gene ehn-3 is expressed specifically in SGPs and is required for their development into differentiated tissues of the somatic gonad. To find novel genes involved in SGP development, we used a weak allele of ehn-3 as the basis for a reverse genetic screen. Feeding RNAi was used to screen ∼2400 clones consisting of transcription factors, signaling components, and chromatin factors. The screen identified five members of the C. elegans SWI/SNF chromatin remodeling complex as genetic enhancers of ehn-3. We characterized alleles of 10 SWI/SNF genes and found that SWI/SNF subunits are required for viability and gonadogenesis. Two conserved SWI/SNF complexes, PBAF and BAF, are defined by their unique array of accessory subunits around a common enzymatic core that includes a catalytic Swi2/Snf2-type ATPase. Tissue-specific RNAi experiments suggest that C. elegans PBAF and BAF complexes control different processes during somatic gonadal development: PBRM-1, a signature subunit of PBAF, is important for normal SGP development, whereas LET-526, the distinguishing subunit of BAF, is required for development of a differentiated cell type, the distal tip cell (DTC). We found that the SWSN-4 ATPase subunit is required for SGP and DTC development. Finally, we provide evidence that C. elegans PBAF subunits and hnd-1/dHand are important for the cell fate decision between SGPs and their differentiated sisters, the head mesodermal cells.
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14
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Rogers WA, Grover S, Stringer SJ, Parks J, Rebeiz M, Williams TM. A survey of the trans-regulatory landscape for Drosophila melanogaster abdominal pigmentation. Dev Biol 2014; 385:417-32. [DOI: 10.1016/j.ydbio.2013.11.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 10/07/2013] [Accepted: 11/05/2013] [Indexed: 10/26/2022]
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Chaiyachati BH, Kaundal RK, Zhao J, Wu J, Flavell R, Chi T. LoxP-FRT Trap (LOFT): a simple and flexible system for conventional and reversible gene targeting. BMC Biol 2012. [PMID: 23198860 PMCID: PMC3529186 DOI: 10.1186/1741-7007-10-96] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Background Conditional gene knockout (cKO) mediated by the Cre/LoxP system is indispensable for exploring gene functions in mice. However, a major limitation of this method is that gene KO is not reversible. A number of methods have been developed to overcome this, but each method has its own limitations. Results We describe a simple method we have named LOFT [LoxP-flippase (FLP) recognition target (FRT) Trap], which is capable of reversible cKO and free of the limitations associated with existing techniques. This method involves two alleles of a target gene: a standard floxed allele, and a multi-functional allele bearing an FRT-flanked gene-trap cassette, which inactivates the target gene while reporting its expression with green fluorescent protein (GFP); the trapped allele is thus a null and GFP reporter by default, but is convertible into a wild-type allele. The floxed and trapped alleles can typically be generated using a single construct bearing a gene-trap cassette doubly flanked by LoxP and FRT sites, and can be used independently to achieve conditional and constitutive gene KO, respectively. More importantly, in mice bearing both alleles and also expressing the Cre and FLP recombinases, sequential function of the two enzymes should lead to deletion of the target gene, followed by restoration of its expression, thus achieving reversible cKO. LOFT should be generally applicable to mouse genes, including the growing numbers of genes already floxed; in the latter case, only the trapped alleles need to be generated to confer reversibility to the pre-existing cKO models. LOFT has other applications, including the creation and reversal of hypomorphic mutations. In this study we proved the principle of LOFT in the context of T-cell development, at a hypomorphic allele of Baf57/Smarce1 encoding a subunit of the chromatin-remodeling Brg/Brahma-associated factor (BAF) complex. Interestingly, the FLP used in the current work caused efficient reversal in peripheral T cells but not thymocytes, which is advantageous for studying developmental epigenetic programming of T-cell functions, a fundamental issue in immunology. Conclusions LOFT combines well-established basic genetic methods into a simple and reliable method for reversible gene targeting, with the flexibility of achieving traditional constitutive and conditional KO.
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Affiliation(s)
- Barbara H Chaiyachati
- Department of Immunobiology, Yale University Medical School, 300 Cedar Street, New Haven, CT 06520, USA
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16
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Düring L, Thorsen M, Petersen DSN, Køster B, Jensen TH, Holmberg S. MRN1 implicates chromatin remodeling complexes and architectural factors in mRNA maturation. PLoS One 2012; 7:e44373. [PMID: 23028530 PMCID: PMC3445587 DOI: 10.1371/journal.pone.0044373] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 08/06/2012] [Indexed: 11/18/2022] Open
Abstract
A functional relationship between chromatin structure and mRNA processing events has been suggested, however, so far only a few involved factors have been characterized. Here we show that rsc nhp6ΔΔ mutants, deficient for the function of the chromatin remodeling factor RSC and the chromatin architectural proteins Nhp6A/Nhp6B, accumulate intron-containing pre-mRNA at the restrictive temperature. In addition, we demonstrate that rsc8-ts16 nhp6ΔΔ cells contain low levels of U6 snRNA and U4/U6 di-snRNA that is further exacerbated after two hours growth at the restrictive temperature. This change in U6 snRNA and U4/U6 di-snRNA levels in rsc8-ts16 nhp6ΔΔ cells is indicative of splicing deficient conditions. We identify MRN1 (multi-copy suppressor of rsc nhp6ΔΔ) as a growth suppressor of rsc nhp6ΔΔ synthetic sickness. Mrn1 is an RNA binding protein that localizes both to the nucleus and cytoplasm. Genetic interactions are observed between 2 µm-MRN1 and the splicing deficient mutants snt309Δ, prp3, prp4, and prp22, and additional genetic analyses link MRN1, SNT309, NHP6A/B, SWI/SNF, and RSC supporting the notion of a role of chromatin structure in mRNA processing.
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Affiliation(s)
- Louis Düring
- Department of Biology, Copenhagen BioCenter, University of Copenhagen, Copenhagen, Denmark
| | - Michael Thorsen
- Department of Biology, Copenhagen BioCenter, University of Copenhagen, Copenhagen, Denmark
| | | | - Brian Køster
- Department of Biology, Copenhagen BioCenter, University of Copenhagen, Copenhagen, Denmark
| | - Torben Heick Jensen
- Centre for mRNP Biogenesis and Metabolism, Department of Molecular Biology, Aarhus University, Aarhus, Denmark
| | - Steen Holmberg
- Department of Biology, Copenhagen BioCenter, University of Copenhagen, Copenhagen, Denmark
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17
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Blanco E, Ruiz-Romero M, Beltran S, Bosch M, Punset A, Serras F, Corominas M. Gene expression following induction of regeneration in Drosophila wing imaginal discs. Expression profile of regenerating wing discs. BMC DEVELOPMENTAL BIOLOGY 2010; 10:94. [PMID: 20813047 PMCID: PMC2939566 DOI: 10.1186/1471-213x-10-94] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Accepted: 09/02/2010] [Indexed: 12/15/2022]
Abstract
BACKGROUND Regeneration is the ability of an organism to rebuild a body part that has been damaged or amputated, and can be studied at the molecular level using model organisms. Drosophila imaginal discs, which are the larval primordia of adult cuticular structures, are capable of undergoing regenerative growth after transplantation and in vivo culture into the adult abdomen. RESULTS Using expression profile analyses, we studied the regenerative behaviour of wing discs at 0, 24 and 72 hours after fragmentation and implantation into adult females. Based on expression level, we generated a catalogue of genes with putative role in wing disc regeneration, identifying four classes: 1) genes with differential expression within the first 24 hours; 2) genes with differential expression between 24 and 72 hours; 3) genes that changed significantly in expression levels between the two time periods; 4) genes with a sustained increase or decrease in their expression levels throughout regeneration. Among these genes, we identified members of the JNK and Notch signalling pathways and chromatin regulators. Through computational analysis, we recognized putative binding sites for transcription factors downstream of these pathways that are conserved in multiple Drosophilids, indicating a potential relationship between members of the different gene classes. Experimental data from genetic mutants provide evidence of a requirement of selected genes in wing disc regeneration. CONCLUSIONS We have been able to distinguish various classes of genes involved in early and late steps of the regeneration process. Our data suggests the integration of signalling pathways in the promoters of regulated genes.
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Affiliation(s)
- Enrique Blanco
- Departament de Genètica, and Institut de Biomedicina de la Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Catalonia, Spain
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18
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Lamiable O, Rabhi M, Peronnet F, Locker D, Decoville M. Rm62, a DEAD-box RNA helicase, complexes with DSP1 in Drosophila embryos. Genesis 2010; 48:244-53. [PMID: 20196121 DOI: 10.1002/dvg.20609] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Two main classes of proteins, Polycomb group (PcG) and Trithorax group (TrxG), play a key role in the regulation of homeotic genes. These proteins act in multimeric complexes to remodel chromatin. A third class of proteins named Enhancers of Trithorax and Polycomb (ETP) modulates the activity of TrxG and PcG, but their role remains largely unknown. We previously identified an HMGB-like protein, DSP1 (Dorsal Switch Protein 1), which was classified as an ETP. Preliminary studies have revealed that DSP1 is involved in multimeric complexes. Here we identify a DEAD-box RNA helicase, Rm62, as partner of DSP1 in a 250-kDa complex. Coimmunoprecipitation assays performed on embryo extracts indicate that DSP1 and Rm62 are associated in 3- to 12-h embryos. Furthermore, DSP1 and Rm62 colocalize on polytene chromosomes. Consistent with these results, a mutation in Rm62 enhances a null mutation of dsp1 and also mutations of trxG or PcG, suggesting that Rm62 has characteristics of an ETP. We show here for the first time that an RNA helicase is involved in the maintenance of homeotic genes.
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Affiliation(s)
- O Lamiable
- Centre de Biophysique Moléculaire, CNRS UPR 4301, conventionnée avec l'Université d'Orléans, Orléans, France
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19
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Malik S, Bhaumik SR. Mixed lineage leukemia: histone H3 lysine 4 methyltransferases from yeast to human. FEBS J 2010; 277:1805-21. [PMID: 20236312 DOI: 10.1111/j.1742-4658.2010.07607.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The fourth lysine of histone H3 is post-translationally modified by a methyl group via the action of histone methyltransferase, and such a covalent modification is associated with transcriptionally active and/or repressed chromatin states. Thus, histone H3 lysine 4 methylation has a crucial role in maintaining normal cellular functions. In fact, misregulation of this covalent modification has been implicated in various types of cancer and other diseases. Therefore, a large number of studies over recent years have been directed towards histone H3 lysine 4 methylation and the enzymes involved in this covalent modification in eukaryotes ranging from yeast to human. These studies revealed a set of histone H3 lysine 4 methyltransferases with important cellular functions in different eukaryotes, as discussed here.
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Affiliation(s)
- Shivani Malik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
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20
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Kazantseva A, Sepp M, Kazantseva J, Sadam H, Pruunsild P, Timmusk T, Neuman T, Palm K. N-terminally truncated BAF57 isoforms contribute to the diversity of SWI/SNF complexes in neurons. J Neurochem 2009; 109:807-18. [DOI: 10.1111/j.1471-4159.2009.06005.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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21
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Induction of TLR4-target genes entails calcium/calmodulin-dependent regulation of chromatin remodeling. Proc Natl Acad Sci U S A 2009; 106:1169-74. [PMID: 19164553 DOI: 10.1073/pnas.0811274106] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Upon toll-like receptor 4 (TLR4) signaling in macrophages, the mammalian Swi/Snf-like BAF chromatin remodeling complex is recruited to many TLR4 target genes where it remodels their chromatin to promote transcription. Here, we show that, surprisingly, recruitment is not sufficient for chromatin remodeling; a second event, dependent on calcium/calmodulin (CaM), is additionally required. Calcium/CaM directly binds the HMG domain of the BAF57 subunit within the BAF complex. Calcium/CaM antagonists, including a CaM-binding peptide derived from BAF57, abolish BAF-dependent remodeling and gene expression without compromising BAF recruitment. BAF57 RNAi and BAF57 dominant negative mutants defective in CaM binding similarly impair the induction of BAF target genes. Our data implicate calcium/CaM in TLR4 signaling, and reveal a previously undescribed, recruitment-independent mode of regulation of the BAF complex that is probably achieved through a direct CaM-BAF interaction.
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22
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Carré C, Ciurciu A, Komonyi O, Jacquier C, Fagegaltier D, Pidoux J, Tricoire H, Tora L, Boros IM, Antoniewski C. The Drosophila NURF remodelling and the ATAC histone acetylase complexes functionally interact and are required for global chromosome organization. EMBO Rep 2007; 9:187-92. [PMID: 18084186 DOI: 10.1038/sj.embor.7401141] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Revised: 11/13/2007] [Accepted: 11/16/2007] [Indexed: 11/09/2022] Open
Abstract
Drosophila Gcn5 is the catalytic subunit of the SAGA and ATAC histone acetylase complexes. Here, we show that mutations in Gcn5 and the ATAC component Ada2a induce a decondensation of the male X chromosome, similar to that induced by mutations in the Iswi and Nurf301 subunits of the NURF nucleosome remodelling complex. Genetic studies as well as transcript profiling analysis indicate that ATAC and NURF regulate overlapping sets of target genes during development. In addition, we find that Ada2a chromosome binding and histone H4-Lys12 acetylation are compromised in Iswi and Nurf301 mutants. Our results strongly suggest that NURF is required for ATAC to access the chromatin and to regulate global chromosome organization.
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Affiliation(s)
- Clément Carré
- Department of Developmental Biology/CNRS URA 2578, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France
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23
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Hogan C, Varga-Weisz P. The regulation of ATP-dependent nucleosome remodelling factors. Mutat Res 2007; 618:41-51. [PMID: 17306842 DOI: 10.1016/j.mrfmmm.2006.07.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Accepted: 07/18/2006] [Indexed: 11/17/2022]
Abstract
The plasticity of chromatin is governed by multi-subunit protein complexes that enzymatically regulate chromosomal structure and activity. Such complexes include ATP-dependent chromatin remodelling factors that are involved in many fundamental processes such as transcription, DNA repair, replication and chromosome structure maintenance. Because ATP-dependent chromatin remodelling factors play important roles, it is not surprising to find that their functions are regulated in a plethora of ways, including post-translational modifications of their subunits and subunit composition changes. The activity of these enzymes is modulated by many factors, including linker histones, histone variants, histone chaperones, non-histone chromatin constituents such as HMG-proteins and secondary messengers, such as inositolpolyphosphates. Additionally, specific histone modifications and interaction with site-specific transcriptional regulators direct the targeting of these activities. Understanding the network of mechanisms that control ATP-dependent chromatin remodelling will constitute an important challenge towards our understanding of chromatin dynamics.
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Zraly CB, Middleton FA, Dingwall AK. Hormone-response Genes Are Direct in Vivo Regulatory Targets of Brahma (SWI/SNF) Complex Function. J Biol Chem 2006; 281:35305-15. [PMID: 16990270 DOI: 10.1074/jbc.m607806200] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Metazoan SWI/SNF chromatin remodeling complexes exhibit ATP-dependent activation and repression of target genes. The Drosophila Brahma (SWI/SNF) complex subunits BRM and SNR1 are highly conserved with direct counterparts in yeast (SWI2/SNF2 and SNF5) and mammals (BRG1/hBRM and INI1/hSNF5). BRM encodes the catalytic ATPase required for chromatin remodeling and SNR1 is a regulatory subunit. Importantly, SNR1 mediates ATP-independent repression functions of the complex in cooperation with histone deacetylases and direct contacts with gene-specific repressors. SNR1 and INI1, as components of their respective SWI/SNF complexes, are important for developmental growth control and patterning, with direct function as a tumor suppressor. To identify direct regulatory targets of the Brm complex, we performed oligonucleotide-based transcriptome microarray analyses using RNA isolated from mutant fly strains harboring dominant-negative alleles of snr1 and brm. Steady-state RNA isolated from early pupae was examined, as this developmental stage critically requires Brm complex function. We found the hormone-responsive Ecdysone-induced genes (Eig) were strongly misregulated and that the Brm complex is directly associated with the promoter regions of these genes in vivo. Our results reveal that the Brm complex assists in coordinating hormone-dependent transcription regulation of the Eig genes.
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Affiliation(s)
- Claudia B Zraly
- Cardinal Bernardin Cancer Center, Oncology Institute and Department of Pathology, Loyola University of Chicago, Maywood, Illinois 60153, USA
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25
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Salvaing J, Decoville M, Mouchel-Vielh E, Bussière M, Daulny A, Boldyreva L, Zhimulev I, Locker D, Peronnet F. Corto and DSP1 interact and bind to a maintenance element of the Scr Hox gene: understanding the role of Enhancers of trithorax and Polycomb. BMC Biol 2006; 4:9. [PMID: 16613610 PMCID: PMC1459216 DOI: 10.1186/1741-7007-4-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2006] [Accepted: 04/14/2006] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Polycomb-group genes (PcG) encode proteins that maintain homeotic (Hox) gene repression throughout development. Conversely, trithorax-group (trxG) genes encode positive factors required for maintenance of long term Hox gene activation. Both kinds of factors bind chromatin regions called maintenance elements (ME). Our previous work has shown that corto, which codes for a chromodomain protein, and dsp1, which codes for an HMGB protein, belong to a class of genes called the Enhancers of trithorax and Polycomb (ETP) that interact with both PcG and trxG. Moreover, dsp1 interacts with the Hox gene Scr, the DSP1 protein is present on a Scr ME in S2 cells but not in embryos. To understand better the role of ETP, we addressed genetic and molecular interactions between corto and dsp1. RESULTS We show that Corto and DSP1 proteins co-localize at 91 sites on polytene chromosomes and co-immunoprecipitate in embryos. They interact directly through the DSP1 HMG-boxes and the amino-part of Corto, which contains a chromodomain. In order to search for a common target, we performed a genetic interaction analysis. We observed that corto mutants suppressed dsp11 sex comb phenotypes and enhanced AntpScx phenotypes, suggesting that corto and dsp1 are simultaneously involved in the regulation of Scr. Using chromatin immunoprecipitation of the Scr ME, we found that Corto was present on this ME both in Drosophila S2 cells and in embryos, whereas DSP1 was present only in S2 cells. CONCLUSION Our results reveal that the proteins Corto and DSP1 are differently recruited to a Scr ME depending on whether the ME is active, as seen in S2 cells, or inactive, as in most embryonic cells. The presence of a given combination of ETPs on an ME would control the recruitment of either PcG or TrxG complexes, propagating the silenced or active state.
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Affiliation(s)
- Juliette Salvaing
- UMR 7622, CNRS, Université Pierre et Marie Curie, 9, quai Saint-Bernard, 75252 PARIS cedex 05, France
- University Maastricht, PO Box 616, 6200 MD Maastricht, The Netherlands
| | - Martine Decoville
- UPR 4301, CNRS, Centre de Biophysique Moléculaire Rue Charles Sadron, 45071 Orléans cedex 2, France
| | - Emmanuèle Mouchel-Vielh
- UMR 7622, CNRS, Université Pierre et Marie Curie, 9, quai Saint-Bernard, 75252 PARIS cedex 05, France
| | - Marianne Bussière
- UMR 7622, CNRS, Université Pierre et Marie Curie, 9, quai Saint-Bernard, 75252 PARIS cedex 05, France
| | - Anne Daulny
- UPR 4301, CNRS, Centre de Biophysique Moléculaire Rue Charles Sadron, 45071 Orléans cedex 2, France
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Mc Clintock Building, 11723 NY, USA
| | - Lidiya Boldyreva
- Institute of Cytology and Genetics, Siberian Division of Russian Academy of Sciences, Acad. Lavrentiev Avenue, 10, 630090 Novosibirsk, Russia
| | - Igor Zhimulev
- Institute of Cytology and Genetics, Siberian Division of Russian Academy of Sciences, Acad. Lavrentiev Avenue, 10, 630090 Novosibirsk, Russia
| | - Daniel Locker
- UPR 4301, CNRS, Centre de Biophysique Moléculaire Rue Charles Sadron, 45071 Orléans cedex 2, France
| | - Frédérique Peronnet
- UMR 7622, CNRS, Université Pierre et Marie Curie, 9, quai Saint-Bernard, 75252 PARIS cedex 05, France
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26
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Chen J, Archer TK. Regulating SWI/SNF subunit levels via protein-protein interactions and proteasomal degradation: BAF155 and BAF170 limit expression of BAF57. Mol Cell Biol 2005; 25:9016-27. [PMID: 16199878 PMCID: PMC1265786 DOI: 10.1128/mcb.25.20.9016-9027.2005] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The mammalian SWI/SNF chromatin remodeling complex, whose function is of critical importance in transcriptional regulation, contains approximately 10 protein components. The expression levels of the core SWI/SNF subunits, including BRG1/Brm, BAF155, BAF170, BAF60, hSNF/Ini1, and BAF57, are stoichiometric, with few to no unbound molecules in the cell. Here we report that exogenous expression of the wild type or certain deletion mutants of BAF57, a key subunit that mediates the interaction between the remodeling complex and transcription factors, results in diminished expression of endogenous BAF57. This down-regulation process is mediated by an increase in proteasome-dependent degradation of the BAF57 protein. Furthermore, the protein levels of BAF155/170 dictate the maximum cellular amount of BAF57. We mapped the domains responsible for the interaction between BAF57 and BAF155 and demonstrated that protein-protein interactions between them play an important role in this regulatory process. These findings provide insights into the physiological mechanisms responsible for maintaining the proper stoichiometric levels of the protein components comprising multimeric enzyme complexes.
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Affiliation(s)
- Jianguang Chen
- Chromatin and Gene Expression Section, Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
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27
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Ragab A, Thompson EC, Travers AA. High mobility group proteins HMGD and HMGZ interact genetically with the Brahma chromatin remodeling complex in Drosophila. Genetics 2005; 172:1069-78. [PMID: 16299391 PMCID: PMC1456206 DOI: 10.1534/genetics.105.049957] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many pleiotropic roles have been ascribed to small abundant HMG-Box (HMGB) proteins in higher eukaryotes but their precise function has remained enigmatic. To investigate their function genetically we have generated a defined deficiency uncovering the functionally redundant genes encoding HMGD and HMGZ, the Drosophila counterparts of HMGB1-3 in mammals. The resulting mutant is a strong hypomorphic allele of HmgD/Z. Surprisingly this allele is viable and exhibits only minor morphological defects even when homozygous. However, this allele interacts strongly with mutants of the Brahma chromatin remodeling complex, while no interaction was observed with mutant alleles of other remodeling complexes. We also observe genetic interactions between the HmgD/Z deficiency and some, but not all, known Brahma targets. These include the homeotic genes Sex combs reduced and Antennapedia, as well as the gene encoding the cell-signaling protein Rhomboid. In contrast to more general structural roles previously suggested for these proteins, we infer that a major function of the abundant HMGB proteins in Drosophila is to participate in Brahma-dependent chromatin remodeling at a specific subset of Brahma-dependent promoters.
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Affiliation(s)
- Anan Ragab
- MRC Laboratory of Molecular Biology, Cambridge CB2 2QH, United Kingdom.
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28
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Armstrong JA, Sperling AS, Deuring R, Manning L, Moseley SL, Papoulas O, Piatek CI, Doe CQ, Tamkun JW. Genetic screens for enhancers of brahma reveal functional interactions between the BRM chromatin-remodeling complex and the delta-notch signal transduction pathway in Drosophila. Genetics 2005; 170:1761-74. [PMID: 15944353 PMCID: PMC1449748 DOI: 10.1534/genetics.105.041327] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The Drosophila trithorax group gene brahma (brm) encodes the ATPase subunit of a 2-MDa chromatin-remodeling complex. brm was identified in a screen for transcriptional activators of homeotic genes and subsequently shown to play a global role in transcription by RNA polymerase II. To gain insight into the targeting, function, and regulation of the BRM complex, we screened for mutations that genetically interact with a dominant-negative allele of brm (brm(K804R)). We first screened for dominant mutations that are lethal in combination with a brm(K804R) transgene under control of the brm promoter. In a distinct but related screen, we identified dominant mutations that modify eye defects resulting from expression of brm(K804R) in the eye-antennal imaginal disc. Mutations in three classes of genes were identified in our screens: genes encoding subunits of the BRM complex (brm, moira, and osa), other proteins directly involved in transcription (zerknullt and RpII140), and signaling molecules (Delta and vein). Expression of brm(K804R) in the adult sense organ precursor lineage causes phenotypes similar to those resulting from impaired Delta-Notch signaling. Our results suggest that signaling pathways may regulate the transcription of target genes by regulating the activity of the BRM complex.
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Affiliation(s)
- Jennifer A Armstrong
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California 95064, USA
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29
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Zraly CB, Marenda DR, Dingwall AK. SNR1 (INI1/SNF5) mediates important cell growth functions of the Drosophila Brahma (SWI/SNF) chromatin remodeling complex. Genetics 2005; 168:199-214. [PMID: 15454538 PMCID: PMC1448117 DOI: 10.1534/genetics.104.029439] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
SNR1 is an essential subunit of the Drosophila Brahma (Brm) ATP-dependent chromatin remodeling complex, with counterparts in yeast (SNF5) and mammals (INI1). Increased cell growth and wing patterning defects are associated with a conditional snr1 mutant, while loss of INI1 function is directly linked with aggressive cancers, suggesting important roles in development and growth control. The Brm complex is known to function during G1 phase, where it appears to assist in restricting entry into S phase. In Drosophila, the activity of DmcycE/CDK2 is rate limiting for entry into S phase and we previously found that the Brm complex can suppress a reduced growth phenotype associated with a hypomorphic DmcycE mutant. Our results reveal that SNR1 helps mediate associations between the Brm complex and DmcycE/CDK2 both in vitro and in vivo. Further, disrupting snr1 function suppressed DmcycEJP phenotypes, and increased cell growth defects associated with the conditional snr1E1 mutant were suppressed by reducing DmcycE levels. While the snr1E1-dependent increased cell growth did not appear to be directly associated with altered expression of G1 or G2 cyclins, transcription of the G2-M regulator string/cdc25 was reduced. Thus, in addition to important functions of the Brm complex in G1-S control, the complex also appears to be important for transcription of genes required for cell cycle progression.
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Affiliation(s)
- Claudia B Zraly
- Oncology Institute, Cardinal Bernardin Cancer Center, Stritch School of Medicine, Loyola University of Chicago, Maywood, Illinois 60153, USA
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30
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Srinivasan S, Armstrong JA, Deuring R, Dahlsveen IK, McNeill H, Tamkun JW. The Drosophila trithorax group protein Kismet facilitates an early step in transcriptional elongation by RNA Polymerase II. Development 2005; 132:1623-35. [PMID: 15728673 DOI: 10.1242/dev.01713] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The Drosophila trithorax group gene kismet (kis) was identified in a screen for extragenic suppressors of Polycomb (Pc) and subsequently shown to play important roles in both segmentation and the determination of body segment identities. One of the two major proteins encoded by kis (KIS-L) is related to members of the SWI2/SNF2 and CHD families of ATP-dependent chromatin-remodeling factors. To clarify the role of KIS-L in gene expression, we examined its distribution on larval salivary gland polytene chromosomes. KIS-L is associated with virtually all sites of transcriptionally active chromatin in a pattern that largely overlaps that of RNA Polymerase II (Pol II). The levels of elongating Pol II and the elongation factors SPT6 and CHD1 are dramatically reduced on polytene chromosomes from kis mutant larvae. By contrast, the loss of KIS-L function does not affect the binding of PC to chromatin or the recruitment of Pol II to promoters. These data suggest that KIS-L facilitates an early step in transcriptional elongation by Pol II.
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Affiliation(s)
- Shrividhya Srinivasan
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
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31
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Mohrmann L, Verrijzer CP. Composition and functional specificity of SWI2/SNF2 class chromatin remodeling complexes. ACTA ACUST UNITED AC 2004; 1681:59-73. [PMID: 15627498 DOI: 10.1016/j.bbaexp.2004.10.005] [Citation(s) in RCA: 243] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2004] [Revised: 10/21/2004] [Accepted: 10/22/2004] [Indexed: 01/31/2023]
Abstract
By regulating the structure of chromatin, ATP-dependent chromatin remodeling complexes (remodelers) perform critical functions in the maintenance, transmission and expression of the eukaryotic genome. Although all known chromatin-remodeling complexes contain an ATPase as a central motor subunit, a number of distinct classes have been recognized. Recent studies have emphasized a more extensive functional diversification among closely related chromatin remodeling complexes than previously anticipated. Here, we discuss recent insights in the functional differences between two evolutionary conserved subclasses of SWI/SNF-related chromatin remodeling factors. One subfamily comprises yeast SWI/SNF, fly BAP and mammalian BAF, whereas the other subfamily includes yeast RSC, fly PBAP and mammalian PBAF. We review the subunit composition, conserved protein modules and biological functions of each of these subclasses of SWI/SNF remodelers. In particular, we will focus on the roles of specific subunits in developmental gene control and human diseases. Recent findings suggest that functional diversification among SWI/SNF complexes allows the eukaryotic cell to fine-tune and integrate the execution of diverse biological programs involving the expression, maintenance and duplication of its genome.
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Affiliation(s)
- Lisette Mohrmann
- Gene Regulation Laboratory, Centre for Biomedical Genetics and Department of Molecular and Cell Biology, Leiden University Medical Centre, PO Box 9503, 2300 RA Leiden, The Netherlands
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32
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Längst G, Becker PB. Nucleosome remodeling: one mechanism, many phenomena? ACTA ACUST UNITED AC 2004; 1677:58-63. [PMID: 15020046 DOI: 10.1016/j.bbaexp.2003.10.011] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2003] [Accepted: 10/14/2003] [Indexed: 11/18/2022]
Abstract
The term 'nucleosome remodeling' subsumes a large number of energy-dependent alterations of canonical nucleosome structure, catalyzed by dedicated ATPases in large multiprotein complexes. The importance of these factors for gene regulation and other processes with chromatin substrate have emerged from genetic studies. Mechanistic analyses of nucleosome remodeling by different enzymes provided a diverse, almost confusing phenomenology of ATP-dependent derangement of nucleosomes in vitro, suggesting that different remodeling machines follow different strategies to disrupt histone-DNA interactions. This review explores the alternative possibility that the rich phenomenology of nucleosome remodeling may be brought about by variations of one basic remodeling reaction.
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Affiliation(s)
- Gernot Längst
- Adolf-Butenandt-Institut, Molekularbiologie, Ludwig-Maximilians-University Munchen, Schillerstrasse 44, D-80336 Munich, Germany
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33
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Wilsker D, Patsialou A, Zumbrun SD, Kim S, Chen Y, Dallas PB, Moran E. The DNA-binding properties of the ARID-containing subunits of yeast and mammalian SWI/SNF complexes. Nucleic Acids Res 2004; 32:1345-53. [PMID: 14982958 PMCID: PMC390273 DOI: 10.1093/nar/gkh277] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
SWI/SNF complexes are ATP-dependent chromatin remodeling complexes that are highly conserved from yeast to human. From yeast to human the complexes contain a subunit with an ARID (A-T-rich interaction domain) DNA-binding domain. In yeast this subunit is SWI1 and in human there are two closely related alternative subunits, p270 and ARID1B. We describe here a comparison of the DNA-binding properties of the yeast and human SWI/SNF ARID-containing subunits. We have determined that SWI1 is an unusual member of the ARID family in both its ARID sequence and in the fact that its DNA-binding affinity is weaker than that of other ARID family members, including its human counterparts, p270 and ARID1B. Sequence analysis and substitution mutagenesis reveals that the weak DNA-binding affinity of the SWI1 ARID is an intrinsic feature of its sequence, arising from specific variations in the major groove interaction site. In addition, this work confirms the finding that p270 binds DNA without regard to sequence specificity, excluding the possibility that the intrinsic role of the ARID is to recruit SWI/SNF complexes to specific promoter sequences. These results emphasize that care must be taken when comparing yeast and higher eukaryotic SWI/SNF complexes in terms of DNA-binding mechanisms.
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Affiliation(s)
- Deborah Wilsker
- Fels Institute for Cancer Research, Temple University School of Medicine, Philadelphia, PA, USA
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34
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Bonaldi T, Längst G, Strohner R, Becker PB, Bianchi ME. The DNA chaperone HMGB1 facilitates ACF/CHRAC-dependent nucleosome sliding. EMBO J 2004. [PMID: 12486007 DOI: 10.1093/embo/cdf692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Nucleosome remodelling complexes CHRAC and ACF contribute to chromatin dynamics by converting chemical energy into sliding of histone octamers on DNA. Their shared ATPase subunit ISWI binds DNA at the sites of entry into the nucleosome. A prevalent model assumes that DNA distortions catalysed by ISWI are converted into relocation of DNA relative to a histone octamer. HMGB1, one of the most abundant nuclear non-histone proteins, binds with preference to distorted DNA. We have now found that transient interaction of HMGB1 with nucleosomal linker DNA overlapping ISWI-binding sites enhances the ability of ACF to bind nucleosomal DNA and accelerates the sliding activity of limiting concentrations of remodelling factor. By contrast, an HMGB1 mutant with increased binding affinity was inhibitory. These observations are consistent with a role for HMGB1 as a DNA chaperone facilitating the rate-limiting DNA distortion during nucleosome remodelling.
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Affiliation(s)
- Tiziana Bonaldi
- Adolf-Butenandt Institut, Molekularbiologie, Schillerstrasse 44, D-80336 München, Germany
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35
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Ragab A, Travers A. HMG-D and histone H1 alter the local accessibility of nucleosomal DNA. Nucleic Acids Res 2004; 31:7083-9. [PMID: 14654683 PMCID: PMC291865 DOI: 10.1093/nar/gkg923] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
There is evidence that HMGB proteins facilitate, while linker histones inhibit chromatin remodelling, respectively. We have examined the effects of HMG-D and histone H1/H5 on accessibility of nucleosomal DNA. Using the 601.2 nucleosome positioning sequence designed by Widom and colleagues we assembled nucleosomes in vitro and probed DNA accessibility with restriction enzymes in the presence or absence of HMG-D and histone H1/H5. For HMG-D our results show increased digestion at two spatially adjacent sites, the dyad and one terminus of nucleosomal DNA. Elsewhere varying degrees of protection from digestion were observed. The C-terminal acidic tail of HMG-D is essential for this pattern of accessibility. Neither the HMG domain by itself nor in combination with the adjacent basic region is sufficient. Histone H1/H5 binding produces two sites of increased digestion on opposite faces of the nucleosome and decreased digestion at all other sites. Our results provide the first evidence of local changes in the accessibility of nucleosomal DNA upon separate interaction with two linker binding proteins.
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Affiliation(s)
- Anan Ragab
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
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36
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Chromosomal HMG-box proteins. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/s0167-7306(03)39005-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
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37
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Szerlong H, Saha A, Cairns BR. The nuclear actin-related proteins Arp7 and Arp9: a dimeric module that cooperates with architectural proteins for chromatin remodeling. EMBO J 2003; 22:3175-87. [PMID: 12805231 PMCID: PMC162148 DOI: 10.1093/emboj/cdg296] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2002] [Revised: 04/28/2003] [Accepted: 04/28/2003] [Indexed: 11/12/2022] Open
Abstract
Nuclear actin-related proteins (ARPs) are essential components of chromatin remodeling and modifying complexes, but their functions and relationship to actin remain elusive. The yeast SWI/SNF and RSC complexes contain Arp7 and Arp9, and are shown to form a stable heterodimer with the properties of a functional module. Arp7 and Arp9 rely on their actin-related regions for heterodimerization, and their unique C-termini cooperate for assembly into RSC. We suggest that regulated ARP-ARP (and possibly ARP-beta-actin) heterodimerization might be a conserved feature of chromatin complexes. A RSC complex lacking Arp7/9 was isolated that displays robust nucleosome remodeling activity, suggesting a separate essential role for ARPs in the regulation of chromatin structure. A screen for suppressors of arp mutations yielded the DNA bending architectural transcription factor Nhp6, which interacts with RSC complex physically and functionally and shows facilitated binding to nucleosomes by RSC. We propose that Arp7/9 dimers function with DNA bending proteins to facilitate proper chromatin architecture and complex- complex interactions.
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Affiliation(s)
- Heather Szerlong
- Howard Hughes Medical Institute, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
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38
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Abstract
Members of the Swi/Snf family of chromatin-remodeling complexes play critical roles in transcriptional control. Recent studies have made significant advances in our understanding of the fundamental aspects of Swi/Snf complexes, including the roles of specific subunits, the repression of transcription, and the mechanism of remodeling. In addition, new findings also indicate an important role for the Swi/Snf-related complex, RSC, in controlling gene expression.
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Affiliation(s)
- Joseph A Martens
- Department of Genetics, Harvard Medical School, 200 Longwood Avenue, Boston, Massachusetts 02115, USA
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39
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Travers AA. Priming the nucleosome: a role for HMGB proteins? EMBO Rep 2003; 4:131-6. [PMID: 12612600 PMCID: PMC1315838 DOI: 10.1038/sj.embor.embor741] [Citation(s) in RCA: 159] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2002] [Accepted: 12/20/2002] [Indexed: 11/09/2022] Open
Abstract
The high-mobility-group B (HMGB) chromosomal proteins are characterized by the HMG box, a DNA-binding domain that both introduces a tight bend into DNA and binds preferentially to a variety of distorted DNA structures. The HMGB proteins seem to act primarily as architectural facilitators in the manipulation of nucleoprotein complexes; for example, in the assembly of complexes involved in recombination and transcription. Recent genetic and biochemical evidence suggests that these proteins can facilitate nucleosome remodelling. One mechanism by which HMGB proteins could prime the nucleosome for migration is to loosen the wrapped DNA and so enhance accessibility to chromatin-remodelling complexes and possibly also to transcription factors. By constraining a tight loop of untwisted DNA at the edge of a nucleosome, an HMGB protein could induce movements in the contacts between certain core histones that would result in an overall change in nucleosome structure.
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Affiliation(s)
- Andrew A Travers
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
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40
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Corona DF, Armstrong JA, Tamkun JW. Genetic and Cytological Analysis of Drosophila Chromatin-Remodeling Factors. Methods Enzymol 2003; 377:70-85. [PMID: 14979019 DOI: 10.1016/s0076-6879(03)77004-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Davide F Corona
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, California 95064, USA
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41
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Marenda DR, Zraly CB, Feng Y, Egan S, Dingwall AK. The Drosophila SNR1 (SNF5/INI1) subunit directs essential developmental functions of the Brahma chromatin remodeling complex. Mol Cell Biol 2003; 23:289-305. [PMID: 12482982 PMCID: PMC140686 DOI: 10.1128/mcb.23.1.289-305.2003] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Drosophila melanogaster Brahma (Brm) complex, a counterpart of the Saccharomyces cerevisiae SWI/SNF ATP-dependent chromatin remodeling complex, is important for proper development by maintaining specific gene expression patterns. The SNR1 subunit is strongly conserved with yeast SNF5 and mammalian INI1 and is required for full activity of the Brm complex. We identified a temperature-sensitive allele of snr1 caused by a single amino acid substitution in the conserved repeat 2 region, implicated in a variety of protein-protein interactions. Genetic analyses of snr1(E1) reveal that it functions as an antimorph and that snr1 has critical roles in tissue patterning and growth control. Temperature shifts show that snr1 is continuously required, with essential functions in embryogenesis, pupal stages, and adults. Allele-specific genetic interactions between snr1(E1) and mutations in genes encoding other members of the Brm complex suggest that snr1(E1) mutant phenotypes result from reduced Brm complex function. Consistent with this view, SNR1(E1) is stably associated with other components of the Brm complex at the restrictive temperature. SNR1 can establish direct contacts through the conserved repeat 2 region with the SET domain of the homeotic regulator Trithorax (TRX), and SNR1(E1) is partially defective for functional TRX association. As truncating mutations of INI1 are strongly correlated with aggressive cancers, our results support the view that SNR1, and specifically the repeat 2 region, has a critical role in mediating cell growth control functions of the metazoan SWI/SNF complexes.
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Affiliation(s)
- Daniel R Marenda
- Department of Biology, Syracuse University, New York 13244-1270, USA
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42
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Bonaldi T, Längst G, Strohner R, Becker PB, Bianchi ME. The DNA chaperone HMGB1 facilitates ACF/CHRAC-dependent nucleosome sliding. EMBO J 2002; 21:6865-73. [PMID: 12486007 PMCID: PMC139112 DOI: 10.1093/emboj/cdf692] [Citation(s) in RCA: 204] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2002] [Revised: 10/11/2002] [Accepted: 11/05/2002] [Indexed: 11/14/2022] Open
Abstract
Nucleosome remodelling complexes CHRAC and ACF contribute to chromatin dynamics by converting chemical energy into sliding of histone octamers on DNA. Their shared ATPase subunit ISWI binds DNA at the sites of entry into the nucleosome. A prevalent model assumes that DNA distortions catalysed by ISWI are converted into relocation of DNA relative to a histone octamer. HMGB1, one of the most abundant nuclear non-histone proteins, binds with preference to distorted DNA. We have now found that transient interaction of HMGB1 with nucleosomal linker DNA overlapping ISWI-binding sites enhances the ability of ACF to bind nucleosomal DNA and accelerates the sliding activity of limiting concentrations of remodelling factor. By contrast, an HMGB1 mutant with increased binding affinity was inhibitory. These observations are consistent with a role for HMGB1 as a DNA chaperone facilitating the rate-limiting DNA distortion during nucleosome remodelling.
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Affiliation(s)
- Tiziana Bonaldi
- Adolf-Butenandt Institut, Molekularbiologie, Schillerstrasse 44, D-80336 München, Germany,
DIBIT, San Raffaele Scientific Institute and Università Vita Salute San Raffaele, Via Olgettina 58, 4, I-20132 Milano, Italy Corresponding author e-mail: T.Bonaldi and G.Längst contributed equally to this work
| | | | | | - Peter B. Becker
- Adolf-Butenandt Institut, Molekularbiologie, Schillerstrasse 44, D-80336 München, Germany,
DIBIT, San Raffaele Scientific Institute and Università Vita Salute San Raffaele, Via Olgettina 58, 4, I-20132 Milano, Italy Corresponding author e-mail: T.Bonaldi and G.Längst contributed equally to this work
| | - Marco E. Bianchi
- Adolf-Butenandt Institut, Molekularbiologie, Schillerstrasse 44, D-80336 München, Germany,
DIBIT, San Raffaele Scientific Institute and Università Vita Salute San Raffaele, Via Olgettina 58, 4, I-20132 Milano, Italy Corresponding author e-mail: T.Bonaldi and G.Längst contributed equally to this work
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43
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Abstract
It has been a long-standing challenge to decipher the principles that enable cells to both organize their genomes into compact chromatin and ensure that the genetic information remains accessible to regulatory factors and enzymes within the confines of the nucleus. The discovery of nucleosome remodeling activities that utilize the energy of ATP to render nucleosomal DNA accessible has been a great leap forward. In vitro, these enzymes weaken the tight wrapping of DNA around the histone octamers, thereby facilitating the sliding of histone octamers to neighboring DNA segments, their displacement to unlinked DNA, and the accumulation of patches of accessible DNA on the surface of nucleosomes. It is presumed that the collective action of these enzymes endows chromatin with dynamic properties that govern all nuclear functions dealing with chromatin as a substrate. The diverse set of ATPases that qualify as the molecular motors of the nucleosome remodeling process have a common history and are part of a superfamily. The physiological context of their remodeling action builds on the association with a wide range of other proteins to form distinct complexes for nucleosome remodeling. This review summarizes the recent progress in our understanding of the mechanisms underlying the nucleosome remodeling reaction, the targeting of remodeling machines to selected sites in chromatin, and their integration into complex regulatory schemes.
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Affiliation(s)
- Peter B Becker
- Adolf-Butenandt-Institut, Molekularbiologie, 80336 Munich, Germany.
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44
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Moshkin YM, Armstrong JA, Maeda RK, Tamkun JW, Verrijzer P, Kennison JA, Karch F. Histone chaperone ASF1 cooperates with the Brahma chromatin-remodelling machinery. Genes Dev 2002; 16:2621-6. [PMID: 12381660 PMCID: PMC187460 DOI: 10.1101/gad.231202] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
De novo chromatin assembly into regularly spaced nucleosomal arrays is essential for eukaryotic genome maintenance and inheritance. The Anti-Silencing Function 1 protein (ASF1) has been shown to be a histone chaperone, participating in DNA-replication-coupled nucleosome assembly. We show that mutations in the Drosophila asf1 gene derepress silencing at heterochromatin and that the ASF1 protein has a cell cycle-specific nuclear and cytoplasmic localization. Furthermore, using both genetic and biochemical methods, we demonstrate that ASF1 interacts with the Brahma (SWI/SNF) chromatin-remodelling complex. These findings suggest that ASF1 plays a crucial role in both chromatin assembly and SWI/SNF-mediated chromatin remodelling.
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Affiliation(s)
- Yuri M Moshkin
- Department of Zoology and Animal Biology, University of Geneva, 1211 Geneva 4, Switzerland
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45
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Armstrong JA, Papoulas O, Daubresse G, Sperling AS, Lis JT, Scott MP, Tamkun JW. The Drosophila BRM complex facilitates global transcription by RNA polymerase II. EMBO J 2002; 21:5245-54. [PMID: 12356740 PMCID: PMC129039 DOI: 10.1093/emboj/cdf517] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Drosophila brahma (brm) encodes the ATPase subunit of a 2 MDa complex that is related to yeast SWI/SNF and other chromatin-remodeling complexes. BRM was identified as a transcriptional activator of Hox genes required for the specification of body segment identities. To clarify the role of the BRM complex in the transcription of other genes, we examined its distribution on larval salivary gland polytene chromosomes. The BRM complex is associated with nearly all transcriptionally active chromatin in a pattern that is generally non-overlapping with that of Polycomb, a repressor of Hox gene transcription. Reduction of BRM function dramatically reduces the association of RNA polymerase II with salivary gland chromosomes. A few genes, such as induced heat shock loci, are not associated with the BRM complex; transcription of these genes is not compromised by loss of BRM function. The distribution of the BRM complex thus correlates with a dependence on BRM for gene activity. These data suggest that the chromatin remodeling activity of the BRM complex plays a general role in facilitating transcription by RNA polymerase II.
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Affiliation(s)
| | | | - Gary Daubresse
- Department of Molecular, Cell, and Developmental Biology, University of California-Santa Cruz, Santa Cruz, CA 95064,
Departments of Developmental Biology and Genetics, Howard Hughes Medical Institute, Beckman Center, Stanford University School of Medicine, Stanford, CA 94305 and Department of Molecular Biology and Genetics, Biotechnology Building, Cornell University, Ithaca, NY 14853, USA Corresponding author e-mail:
| | | | - John T. Lis
- Department of Molecular, Cell, and Developmental Biology, University of California-Santa Cruz, Santa Cruz, CA 95064,
Departments of Developmental Biology and Genetics, Howard Hughes Medical Institute, Beckman Center, Stanford University School of Medicine, Stanford, CA 94305 and Department of Molecular Biology and Genetics, Biotechnology Building, Cornell University, Ithaca, NY 14853, USA Corresponding author e-mail:
| | - Matthew P. Scott
- Department of Molecular, Cell, and Developmental Biology, University of California-Santa Cruz, Santa Cruz, CA 95064,
Departments of Developmental Biology and Genetics, Howard Hughes Medical Institute, Beckman Center, Stanford University School of Medicine, Stanford, CA 94305 and Department of Molecular Biology and Genetics, Biotechnology Building, Cornell University, Ithaca, NY 14853, USA Corresponding author e-mail:
| | - John W. Tamkun
- Department of Molecular, Cell, and Developmental Biology, University of California-Santa Cruz, Santa Cruz, CA 95064,
Departments of Developmental Biology and Genetics, Howard Hughes Medical Institute, Beckman Center, Stanford University School of Medicine, Stanford, CA 94305 and Department of Molecular Biology and Genetics, Biotechnology Building, Cornell University, Ithaca, NY 14853, USA Corresponding author e-mail:
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46
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Belandia B, Orford RL, Hurst HC, Parker MG. Targeting of SWI/SNF chromatin remodelling complexes to estrogen-responsive genes. EMBO J 2002; 21:4094-103. [PMID: 12145209 PMCID: PMC126156 DOI: 10.1093/emboj/cdf412] [Citation(s) in RCA: 182] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2002] [Revised: 06/13/2002] [Accepted: 06/13/2002] [Indexed: 11/13/2022] Open
Abstract
SWI/SNF complexes are ATP-dependent chromatin remodelling enzymes that have been implicated in the regulation of gene expression in yeast and higher eukaryotes. BRG1, a catalytic subunit in the mammalian SWI/SNF complex, is required for transcriptional activation by the estrogen receptor, but the mechanisms by which the complex is recruited to estrogen target genes are unknown. Here, we have identified an interaction between the estrogen receptor and BAF57, a subunit present only in mammalian SWI/SNF complexes, which is stimulated by estrogen and requires both a functional hormone-binding domain and the DNA-binding region of the receptor. We also found an additional interaction between the p160 family of coactivators and BAF57 and demonstrate that the ability of p160 coactivators to potentiate transcription by the estrogen receptor is dependent on BAF57 in transfected cells. Moreover, chromatin immunoprecipitation assays demonstrated that BAF57 is recruited to the estrogen-responsive promoter, pS2, in a ligand-dependent manner. These results suggest that one of the mechanisms for recruiting SWI/SNF complexes to estrogen target genes is by means of BAF57.
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MESH Headings
- Amino Acid Substitution
- Animals
- Binding Sites
- COS Cells
- Carcinoma/pathology
- Chlorocebus aethiops
- Chromosomal Proteins, Non-Histone/chemistry
- Chromosomal Proteins, Non-Histone/genetics
- Chromosomal Proteins, Non-Histone/physiology
- DNA Helicases
- Estradiol/analogs & derivatives
- Estradiol/pharmacology
- Estrogen Antagonists/pharmacology
- Estrogen Receptor alpha
- Fulvestrant
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/physiology
- HeLa Cells
- Histone Acetyltransferases
- Humans
- Macromolecular Substances
- Mice
- Nuclear Proteins/deficiency
- Nuclear Proteins/genetics
- Nuclear Proteins/physiology
- Nuclear Receptor Coactivator 1
- Nuclear Receptor Coactivator 2
- Nuclear Receptor Coactivator 3
- Promoter Regions, Genetic
- Protein Binding
- Protein Interaction Mapping
- Protein Structure, Tertiary
- Receptors, Estrogen/chemistry
- Receptors, Estrogen/genetics
- Receptors, Estrogen/physiology
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/physiology
- Saccharomyces cerevisiae
- Transcription Factors/chemistry
- Transcription Factors/deficiency
- Transcription Factors/genetics
- Transcription Factors/physiology
- Transcription, Genetic/drug effects
- Transcription, Genetic/physiology
- Transfection
- Tumor Cells, Cultured/drug effects
- Two-Hybrid System Techniques
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Affiliation(s)
| | - Rob L. Orford
- Institute of Reproductive and Developmental Biology, Imperial College Faculty of Medicine, Du Cane Road and
Cancer Research UK Molecular Oncology Unit, Hammersmith Hospital, London W12 0NN, UK Corresponding author e-mail:
| | - Helen C. Hurst
- Institute of Reproductive and Developmental Biology, Imperial College Faculty of Medicine, Du Cane Road and
Cancer Research UK Molecular Oncology Unit, Hammersmith Hospital, London W12 0NN, UK Corresponding author e-mail:
| | - Malcolm G. Parker
- Institute of Reproductive and Developmental Biology, Imperial College Faculty of Medicine, Du Cane Road and
Cancer Research UK Molecular Oncology Unit, Hammersmith Hospital, London W12 0NN, UK Corresponding author e-mail:
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47
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Domingos PM, Obukhanych TV, Altmann CR, Hemmati-Brivanlou A. Cloning and developmental expression of Baf57 in Xenopus laevis. Mech Dev 2002; 116:177-81. [PMID: 12128220 DOI: 10.1016/s0925-4773(02)00129-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Mammalian and Drosophila homologues of Baf57 have been previously isolated as being a subunit of SWI/SNF-like chromatin remodeling complexes. Here, we report the cloning and developmental expression of Xenopus Baf57. We isolated XBaf57 by using an expression cloning approach to identify novel modulators of Xenopus Smad7. XBaf57 co-operates with XSmad7 by increasing the expression of neural markers in ectodermal explants. XBaf57 is expressed in the ectoderm and pre-involuting mesoderm during gastrula stages and in the central nervous system during neurula and tailbud stages. These results raise the possibility that XBaf57 (or XBaf57-containing chromatin remodelling complexes) may be involved in the process of neural induction during Xenopus embryonic development.
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Affiliation(s)
- Pedro M Domingos
- Laboratory of Molecular Embryology, The Rockefeller University, 1230 York Avenue, New York, NY 10021-6399, USA
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Simon JA, Tamkun JW. Programming off and on states in chromatin: mechanisms of Polycomb and trithorax group complexes. Curr Opin Genet Dev 2002; 12:210-8. [PMID: 11893495 DOI: 10.1016/s0959-437x(02)00288-5] [Citation(s) in RCA: 282] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Polycomb and trithorax group proteins are evolutionarily conserved chromatin components that maintain stable states of gene expression. Recent studies have identified and characterized several multiprotein complexes containing these transcriptional regulators. Advances in understanding molecular activities of these complexes in vitro, and functional domains present in their subunits, suggest that they control transcription through multistep mechanisms that involve nucleosome modification, chromatin remodeling, and interaction with general transcription factors.
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Affiliation(s)
- Jeffrey A Simon
- Department of Genetics, Cell Biology and Development, University of Minnesota, 321 Church St., Minneapolis, Minnesota 55455, USA.
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Corona DFV, Clapier CR, Becker PB, Tamkun JW. Modulation of ISWI function by site-specific histone acetylation. EMBO Rep 2002; 3:242-7. [PMID: 11882543 PMCID: PMC1084020 DOI: 10.1093/embo-reports/kvf056] [Citation(s) in RCA: 189] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Mutations in Drosophila ISWI, a member of the SWI2/SNF2 family of chromatin remodeling ATPases, alter the global architecture of the male X chromosome. The transcription of genes on this chromosome is increased 2-fold relative to females due to dosage compensation, a process involving the acetylation of histone H4 at lysine 16 (H4K16). Here we show that blocking H4K16 acetylation suppresses the X chromosome defects resulting from loss of ISWI function in males. In contrast, the forced acetylation of H4K16 in ISWI mutant females causes X chromosome defects indistinguishable from those seen in ISWI mutant males. Increased expression of MOF, the histone acetyltransferase that acetylates H4K16, strongly enhances phenotypes resulting from the partial loss of ISWI function. Peptide competition assays revealed that H4K16 acetylation reduces the ability of ISWI to interact productively with its substrate. These findings suggest that H4K16 acetylation directly counteracts chromatin compaction mediated by the ISWI ATPase.
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Affiliation(s)
- Davide F V Corona
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
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Abstract
Members of the HMGA (a.k.a. HMGI/Y) family of 'high mobility group' (HMG) proteins participate in a wide variety of nuclear processes ranging from chromosome and chromatin mechanics to acting as architectural transcription factors that regulate the expression of numerous genes in vivo. As a consequence, they function in the cell as highly connected 'nodes' of protein-DNA and protein-protein interactions that influence a diverse array of normal biological processes including growth, proliferation, differentiation and death. The HMGA proteins, likewise, participate in pathological processes by, for example, acting as regulators of viral gene transcription and by serving as host-supplied proteins that facilitate retroviral integration. HMGA genes are bona fide proto-oncogenes that promote tumor progression and metastasis when overexpressed in cells. High constitutive HMGA protein levels are among the most consistent feature observed in all types of cancers with increasing concentrations being correlated with increasing malignancy. The intrinsic attributes that endow the HMGA proteins with these remarkable abilities are a combination of structural, biochemical and biological characteristics that are unique to these proteins. HMGA proteins have little, if any, secondary structure while free in solution but undergo disordered-to-ordered structural transitions when bound to substrates such as DNA or other proteins. Each protein contains three copies of a conserved DNA-binding peptide motif called the 'AT-hook' that preferentially binds to the minor groove of stretches of AT-rich sequence. In vivo HMGA proteins specifically interact with a large number of other proteins, most of which are transcription factors. They are also subject to many types of in vivo biochemical modifications that markedly influence their ability to interact with DNA substrates, other proteins and chromatin. And, most importantly, both the transcription of HMGA genes and the biochemical modifications of HMGA proteins are direct downstream targets of numerous signal transduction pathways making them exquisitely responsive to various environmental influences. This review covers recent advances that have contributed to our understanding of how this constellation of structural and biological features allows the HMGA proteins to serve as central 'hubs' of nuclear function.
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Affiliation(s)
- R Reeves
- Department of Biochemistry and Biophysics, School of Molecular Biosciences, Washington State University, Pullman, WA 99164-4660, USA.
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