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  • 11
    Publication Date: 2010-05-04
    Description: Polycomb group (PcG) proteins are transcriptional repressors that control processes ranging from the maintenance of cell fate decisions and stem cell pluripotency in animals to the control of flowering time in plants. In Drosophila, genetic studies identified more than 15 different PcG proteins that are required to repress homeotic (HOX) and other developmental regulator genes in cells where they must stay inactive. Biochemical analyses established that these PcG proteins exist in distinct multiprotein complexes that bind to and modify chromatin of target genes. Among those, Polycomb repressive complex 1 (PRC1) and the related dRing-associated factors (dRAF) complex contain an E3 ligase activity for monoubiquitination of histone H2A (refs 1-4). Here we show that the uncharacterized Drosophila PcG gene calypso encodes the ubiquitin carboxy-terminal hydrolase BAP1. Biochemically purified Calypso exists in a complex with the PcG protein ASX, and this complex, named Polycomb repressive deubiquitinase (PR-DUB), is bound at PcG target genes in Drosophila. Reconstituted recombinant Drosophila and human PR-DUB complexes remove monoubiquitin from H2A but not from H2B in nucleosomes. Drosophila mutants lacking PR-DUB show a strong increase in the levels of monoubiquitinated H2A. A mutation that disrupts the catalytic activity of Calypso, or absence of the ASX subunit abolishes H2A deubiquitination in vitro and HOX gene repression in vivo. Polycomb gene silencing may thus entail a dynamic balance between H2A ubiquitination by PRC1 and dRAF, and H2A deubiquitination by PR-DUB.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3182123/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3182123/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Scheuermann, Johanna C -- de Ayala Alonso, Andres Gaytan -- Oktaba, Katarzyna -- Ly-Hartig, Nga -- McGinty, Robert K -- Fraterman, Sven -- Wilm, Matthias -- Muir, Tom W -- Muller, Jurg -- R01 GM086868/GM/NIGMS NIH HHS/ -- R01 GM086868-13/GM/NIGMS NIH HHS/ -- RC2 CA148354/CA/NCI NIH HHS/ -- RC2 CA148354-02/CA/NCI NIH HHS/ -- RC2CA148354/CA/NCI NIH HHS/ -- England -- Nature. 2010 May 13;465(7295):243-7. doi: 10.1038/nature08966. Epub 2010 May 2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20436459" target="_blank"〉PubMed〈/a〉
    Keywords: Alleles ; Animals ; Biocatalysis ; Drosophila Proteins/genetics/*metabolism ; Drosophila melanogaster/embryology/*enzymology/genetics/metabolism ; Gene Silencing ; Genes, Homeobox/genetics ; Genes, Insect/genetics ; Genetic Complementation Test ; Histones/*metabolism ; Humans ; Multiprotein Complexes/chemistry/isolation & purification/*metabolism ; Nucleosomes/chemistry/metabolism ; Polycomb Repressive Complex 1 ; Repressor Proteins/genetics/isolation & purification/*metabolism ; Ubiquitin/metabolism ; Ubiquitin Thiolesterase/chemistry/genetics/*metabolism ; Ubiquitination/*physiology
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    Electronic ISSN: 1476-4687
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  • 12
    Publication Date: 2010-01-19
    Description: Influenza A virus, being responsible for seasonal epidemics and reoccurring pandemics, represents a worldwide threat to public health. High mutation rates facilitate the generation of viral escape mutants, rendering vaccines and drugs directed against virus-encoded targets potentially ineffective. In contrast, targeting host cell determinants temporarily dispensable for the host but crucial for virus replication could prevent viral escape. Here we report the discovery of 287 human host cell genes influencing influenza A virus replication in a genome-wide RNA interference (RNAi) screen. Using an independent assay we confirmed 168 hits (59%) inhibiting either the endemic H1N1 (119 hits) or the current pandemic swine-origin (121 hits) influenza A virus strains, with an overlap of 60%. Notably, a subset of these common hits was also essential for replication of a highly pathogenic avian H5N1 strain. In-depth analyses of several factors provided insights into their infection stage relevance. Notably, SON DNA binding protein (SON) was found to be important for normal trafficking of influenza virions to late endosomes early in infection. We also show that a small molecule inhibitor of CDC-like kinase 1 (CLK1) reduces influenza virus replication by more than two orders of magnitude, an effect connected with impaired splicing of the viral M2 messenger RNA. Furthermore, influenza-virus-infected p27(-/-) (cyclin-dependent kinase inhibitor 1B; Cdkn1b) mice accumulated significantly lower viral titres in the lung, providing in vivo evidence for the importance of this gene. Thus, our results highlight the potency of genome-wide RNAi screening for the dissection of virus-host interactions and the identification of drug targets for a broad range of influenza viruses.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Karlas, Alexander -- Machuy, Nikolaus -- Shin, Yujin -- Pleissner, Klaus-Peter -- Artarini, Anita -- Heuer, Dagmar -- Becker, Daniel -- Khalil, Hany -- Ogilvie, Lesley A -- Hess, Simone -- Maurer, Andre P -- Muller, Elke -- Wolff, Thorsten -- Rudel, Thomas -- Meyer, Thomas F -- England -- Nature. 2010 Feb 11;463(7282):818-22. doi: 10.1038/nature08760. Epub 2010 Jan 17.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Molecular Biology Department, Max Planck Institute for Infection Biology, Chariteplatz 1, 10117 Berlin, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20081832" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Factors/genetics/metabolism ; Cell Line ; Cells, Cultured ; Chick Embryo ; Cyclin-Dependent Kinase Inhibitor p27/deficiency/genetics/metabolism ; Epithelial Cells/virology ; Genome, Human/genetics ; *Host-Pathogen Interactions/genetics/physiology ; Humans ; Influenza A Virus, H1N1 Subtype/classification/*growth & development ; Influenza, Human/*genetics/*virology ; Lung/cytology ; Mice ; Mice, Inbred C57BL ; Protein-Serine-Threonine Kinases/genetics ; Protein-Tyrosine Kinases/genetics ; *RNA Interference ; Virus Replication/*physiology
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 13
    Publication Date: 2010-09-25
    Description: Plasmodium falciparum is the most prevalent and lethal of the malaria parasites infecting humans, yet the origin and evolutionary history of this important pathogen remain controversial. Here we develop a single-genome amplification strategy to identify and characterize Plasmodium spp. DNA sequences in faecal samples from wild-living apes. Among nearly 3,000 specimens collected from field sites throughout central Africa, we found Plasmodium infection in chimpanzees (Pan troglodytes) and western gorillas (Gorilla gorilla), but not in eastern gorillas (Gorilla beringei) or bonobos (Pan paniscus). Ape plasmodial infections were highly prevalent, widely distributed and almost always made up of mixed parasite species. Analysis of more than 1,100 mitochondrial, apicoplast and nuclear gene sequences from chimpanzees and gorillas revealed that 99% grouped within one of six host-specific lineages representing distinct Plasmodium species within the subgenus Laverania. One of these from western gorillas comprised parasites that were nearly identical to P. falciparum. In phylogenetic analyses of full-length mitochondrial sequences, human P. falciparum formed a monophyletic lineage within the gorilla parasite radiation. These findings indicate that P. falciparum is of gorilla origin and not of chimpanzee, bonobo or ancient human origin.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2997044/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2997044/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Liu, Weimin -- Li, Yingying -- Learn, Gerald H -- Rudicell, Rebecca S -- Robertson, Joel D -- Keele, Brandon F -- Ndjango, Jean-Bosco N -- Sanz, Crickette M -- Morgan, David B -- Locatelli, Sabrina -- Gonder, Mary K -- Kranzusch, Philip J -- Walsh, Peter D -- Delaporte, Eric -- Mpoudi-Ngole, Eitel -- Georgiev, Alexander V -- Muller, Martin N -- Shaw, George M -- Peeters, Martine -- Sharp, Paul M -- Rayner, Julian C -- Hahn, Beatrice H -- P30 AI 7767/AI/NIAID NIH HHS/ -- P30 AI027767/AI/NIAID NIH HHS/ -- P30 AI027767-21A1/AI/NIAID NIH HHS/ -- R01 AI058715/AI/NIAID NIH HHS/ -- R01 AI058715-06A1/AI/NIAID NIH HHS/ -- R01 AI058715-07/AI/NIAID NIH HHS/ -- R01 AI50529/AI/NIAID NIH HHS/ -- R01 I58715/PHS HHS/ -- R03 AI074778/AI/NIAID NIH HHS/ -- R03 AI074778-02/AI/NIAID NIH HHS/ -- R37 AI050529/AI/NIAID NIH HHS/ -- R37 AI050529-07/AI/NIAID NIH HHS/ -- R37 AI050529-08/AI/NIAID NIH HHS/ -- T32 AI007245/AI/NIAID NIH HHS/ -- T32 AI007245-26/AI/NIAID NIH HHS/ -- T32 GM008111/GM/NIGMS NIH HHS/ -- T32 GM008111-13/GM/NIGMS NIH HHS/ -- U19 AI 067854/AI/NIAID NIH HHS/ -- U19 AI067854/AI/NIAID NIH HHS/ -- U19 AI067854-06/AI/NIAID NIH HHS/ -- Howard Hughes Medical Institute/ -- Wellcome Trust/United Kingdom -- England -- Nature. 2010 Sep 23;467(7314):420-5. doi: 10.1038/nature09442.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20864995" target="_blank"〉PubMed〈/a〉
    Keywords: Africa/epidemiology ; Animals ; Animals, Wild/classification/parasitology ; Ape Diseases/epidemiology/*parasitology/transmission ; DNA, Mitochondrial/analysis/genetics ; Evolution, Molecular ; Feces/parasitology ; Genes, Mitochondrial/genetics ; Genetic Variation/genetics ; Genome, Protozoan/genetics ; Gorilla gorilla/classification/*parasitology ; Humans ; Malaria, Falciparum/epidemiology/*parasitology/transmission/*veterinary ; Molecular Sequence Data ; Pan paniscus/parasitology ; Pan troglodytes/parasitology ; Phylogeny ; Plasmodium/classification/genetics/isolation & purification ; Plasmodium falciparum/genetics/*isolation & purification ; Prevalence ; Zoonoses/parasitology/transmission
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    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 14
    Publication Date: 2010-10-29
    Description: Biodiversity is rapidly declining, and this may negatively affect ecosystem processes, including economically important ecosystem services. Previous studies have shown that biodiversity has positive effects on organisms and processes across trophic levels. However, only a few studies have so far incorporated an explicit food-web perspective. In an eight-year biodiversity experiment, we studied an unprecedented range of above- and below-ground organisms and multitrophic interactions. A multitrophic data set originating from a single long-term experiment allows mechanistic insights that would not be gained from meta-analysis of different experiments. Here we show that plant diversity effects dampen with increasing trophic level and degree of omnivory. This was true both for abundance and species richness of organisms. Furthermore, we present comprehensive above-ground/below-ground biodiversity food webs. Both above ground and below ground, herbivores responded more strongly to changes in plant diversity than did carnivores or omnivores. Density and richness of carnivorous taxa was independent of vegetation structure. Below-ground responses to plant diversity were consistently weaker than above-ground responses. Responses to increasing plant diversity were generally positive, but were negative for biological invasion, pathogen infestation and hyperparasitism. Our results suggest that plant diversity has strong bottom-up effects on multitrophic interaction networks, with particularly strong effects on lower trophic levels. Effects on higher trophic levels are indirectly mediated through bottom-up trophic cascades.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Scherber, Christoph -- Eisenhauer, Nico -- Weisser, Wolfgang W -- Schmid, Bernhard -- Voigt, Winfried -- Fischer, Markus -- Schulze, Ernst-Detlef -- Roscher, Christiane -- Weigelt, Alexandra -- Allan, Eric -- Bessler, Holger -- Bonkowski, Michael -- Buchmann, Nina -- Buscot, Francois -- Clement, Lars W -- Ebeling, Anne -- Engels, Christof -- Halle, Stefan -- Kertscher, Ilona -- Klein, Alexandra-Maria -- Koller, Robert -- Konig, Stephan -- Kowalski, Esther -- Kummer, Volker -- Kuu, Annely -- Lange, Markus -- Lauterbach, Dirk -- Middelhoff, Cornelius -- Migunova, Varvara D -- Milcu, Alexandru -- Muller, Ramona -- Partsch, Stephan -- Petermann, Jana S -- Renker, Carsten -- Rottstock, Tanja -- Sabais, Alexander -- Scheu, Stefan -- Schumacher, Jens -- Temperton, Vicky M -- Tscharntke, Teja -- England -- Nature. 2010 Nov 25;468(7323):553-6. doi: 10.1038/nature09492. Epub 2010 Oct 27.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Georg-August-University Gottingen, Department of Crop Sciences, Agroecology, Grisebachstrasse 6, 37077 Gottingen, Germany. christoph.scherber@agr.uni-goettingen.de〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20981010" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biodiversity ; *Models, Biological ; *Plant Physiological Phenomena ; Population Density
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    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 15
    Publication Date: 2010-11-12
    Description: The central amygdala (CEA), a nucleus predominantly composed of GABAergic inhibitory neurons, is essential for fear conditioning. How the acquisition and expression of conditioned fear are encoded within CEA inhibitory circuits is not understood. Using in vivo electrophysiological, optogenetic and pharmacological approaches in mice, we show that neuronal activity in the lateral subdivision of the central amygdala (CEl) is required for fear acquisition, whereas conditioned fear responses are driven by output neurons in the medial subdivision (CEm). Functional circuit analysis revealed that inhibitory CEA microcircuits are highly organized and that cell-type-specific plasticity of phasic and tonic activity in the CEl to CEm pathway may gate fear expression and regulate fear generalization. Our results define the functional architecture of CEA microcircuits and their role in the acquisition and regulation of conditioned fear behaviour.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ciocchi, Stephane -- Herry, Cyril -- Grenier, Francois -- Wolff, Steffen B E -- Letzkus, Johannes J -- Vlachos, Ioannis -- Ehrlich, Ingrid -- Sprengel, Rolf -- Deisseroth, Karl -- Stadler, Michael B -- Muller, Christian -- Luthi, Andreas -- England -- Nature. 2010 Nov 11;468(7321):277-82. doi: 10.1038/nature09559.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21068837" target="_blank"〉PubMed〈/a〉
    Keywords: Action Potentials ; Amygdala/anatomy & histology/cytology/*physiology ; Animals ; Conditioning, Classical/*physiology ; Fear/*physiology ; Freezing Reaction, Cataleptic ; Male ; Mice ; Mice, Inbred C57BL ; Neural Inhibition/*physiology ; Neural Pathways/cytology/*physiology ; Neuronal Plasticity/physiology ; Neurons/physiology ; gamma-Aminobutyric Acid/metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 16
    Publication Date: 2008-08-30
    Description: Stem cells are defined as self-renewing cell populations that can differentiate into multiple distinct cell types. However, hundreds of different human cell lines from embryonic, fetal and adult sources have been called stem cells, even though they range from pluripotent cells-typified by embryonic stem cells, which are capable of virtually unlimited proliferation and differentiation-to adult stem cell lines, which can generate a far more limited repertoire of differentiated cell types. The rapid increase in reports of new sources of stem cells and their anticipated value to regenerative medicine has highlighted the need for a general, reproducible method for classification of these cells. We report here the creation and analysis of a database of global gene expression profiles (which we call the 'stem cell matrix') that enables the classification of cultured human stem cells in the context of a wide variety of pluripotent, multipotent and differentiated cell types. Using an unsupervised clustering method to categorize a collection of approximately 150 cell samples, we discovered that pluripotent stem cell lines group together, whereas other cell types, including brain-derived neural stem cell lines, are very diverse. Using further bioinformatic analysis we uncovered a protein-protein network (PluriNet) that is shared by the pluripotent cells (embryonic stem cells, embryonal carcinomas and induced pluripotent cells). Analysis of published data showed that the PluriNet seems to be a common characteristic of pluripotent cells, including mouse embryonic stem and induced pluripotent cells and human oocytes. Our results offer a new strategy for classifying stem cells and support the idea that pluripotency and self-renewal are under tight control by specific molecular networks.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2637443/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2637443/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Muller, Franz-Josef -- Laurent, Louise C -- Kostka, Dennis -- Ulitsky, Igor -- Williams, Roy -- Lu, Christina -- Park, In-Hyun -- Rao, Mahendra S -- Shamir, Ron -- Schwartz, Philip H -- Schmidt, Nils O -- Loring, Jeanne F -- K12 5K12HD000849-20/HD/NICHD NIH HHS/ -- P20 GM075059/GM/NIGMS NIH HHS/ -- P20 GM075059-01/GM/NIGMS NIH HHS/ -- England -- Nature. 2008 Sep 18;455(7211):401-5. doi: 10.1038/nature07213. Epub 2008 Aug 24.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Regenerative Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA. fj.mueller@zip-kiel.de〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18724358" target="_blank"〉PubMed〈/a〉
    Keywords: Algorithms ; Animals ; Artificial Intelligence ; Cell Differentiation ; Cell Line ; Computational Biology ; Databases, Factual ; Embryonic Stem Cells/classification/metabolism ; *Gene Expression Profiling ; Humans ; Mice ; Multipotent Stem Cells/classification/metabolism ; Oligonucleotide Array Sequence Analysis ; Oocytes/classification/metabolism ; Phenotype ; Pluripotent Stem Cells/classification/metabolism ; Protein Binding ; Stem Cells/*classification/*metabolism
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    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 17
    Publication Date: 2008-07-11
    Description: Switching between exploratory and defensive behaviour is fundamental to survival of many animals, but how this transition is achieved by specific neuronal circuits is not known. Here, using the converse behavioural states of fear extinction and its context-dependent renewal as a model in mice, we show that bi-directional transitions between states of high and low fear are triggered by a rapid switch in the balance of activity between two distinct populations of basal amygdala neurons. These two populations are integrated into discrete neuronal circuits differentially connected with the hippocampus and the medial prefrontal cortex. Targeted and reversible neuronal inactivation of the basal amygdala prevents behavioural changes without affecting memory or expression of behaviour. Our findings indicate that switching between distinct behavioural states can be triggered by selective activation of specific neuronal circuits integrating sensory and contextual information. These observations provide a new framework for understanding context-dependent changes of fear behaviour.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Herry, Cyril -- Ciocchi, Stephane -- Senn, Verena -- Demmou, Lynda -- Muller, Christian -- Luthi, Andreas -- England -- Nature. 2008 Jul 31;454(7204):600-6. doi: 10.1038/nature07166. Epub 2008 Jul 9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland. cyril.herry@fmi.ch〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18615015" target="_blank"〉PubMed〈/a〉
    Keywords: Amygdala/cytology/physiology ; Animals ; Conditioning (Psychology) ; Extinction, Psychological ; Fear/*physiology ; Freezing Reaction, Cataleptic/drug effects/physiology ; Male ; Mice ; Mice, Inbred C57BL ; Models, Animal ; Muscimol/pharmacology ; Neural Pathways ; Neurons/classification/*physiology
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  • 18
    Publication Date: 2009-10-02
    Description: A key step in many chromatin-related processes is the recognition of histone post-translational modifications by effector modules such as bromodomains and chromo-like domains of the Royal family. Whereas effector-mediated recognition of single post-translational modifications is well characterized, how the cell achieves combinatorial readout of histones bearing multiple modifications is poorly understood. One mechanism involves multivalent binding by linked effector modules. For example, the tandem bromodomains of human TATA-binding protein-associated factor-1 (TAF1) bind better to a diacetylated histone H4 tail than to monoacetylated tails, a cooperative effect attributed to each bromodomain engaging one acetyl-lysine mark. Here we report a distinct mechanism of combinatorial readout for the mouse TAF1 homologue Brdt, a testis-specific member of the BET protein family. Brdt associates with hyperacetylated histone H4 (ref. 7) and is implicated in the marked chromatin remodelling that follows histone hyperacetylation during spermiogenesis, the stage of spermatogenesis in which post-meiotic germ cells mature into fully differentiated sperm. Notably, we find that a single bromodomain (BD1) of Brdt is responsible for selectively recognizing histone H4 tails bearing two or more acetylation marks. The crystal structure of BD1 bound to a diacetylated H4 tail shows how two acetyl-lysine residues cooperate to interact with one binding pocket. Structure-based mutagenesis that reduces the selectivity of BD1 towards diacetylated tails destabilizes the association of Brdt with acetylated chromatin in vivo. Structural analysis suggests that other chromatin-associated proteins may be capable of a similar mode of ligand recognition, including yeast Bdf1, human TAF1 and human CBP/p300 (also known as CREBBP and EP300, respectively). Our findings describe a new mechanism for the combinatorial readout of histone modifications in which a single effector module engages two marks on a histone tail as a composite binding epitope.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Moriniere, Jeanne -- Rousseaux, Sophie -- Steuerwald, Ulrich -- Soler-Lopez, Montserrat -- Curtet, Sandrine -- Vitte, Anne-Laure -- Govin, Jerome -- Gaucher, Jonathan -- Sadoul, Karin -- Hart, Darren J -- Krijgsveld, Jeroen -- Khochbin, Saadi -- Muller, Christoph W -- Petosa, Carlo -- England -- Nature. 2009 Oct 1;461(7264):664-8. doi: 10.1038/nature08397.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉European Molecular Biology Laboratory, Grenoble Outstation, 6 rue Jules Horowitz, BP 181, 38042 Grenoble Cedex 9, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19794495" target="_blank"〉PubMed〈/a〉
    Keywords: Acetylation ; Allosteric Regulation ; Animals ; Binding Sites ; COS Cells ; Cercopithecus aethiops ; Chromatin/chemistry/metabolism ; Crystallography, X-Ray ; Histones/*chemistry/*metabolism ; Lysine/metabolism ; Mice ; Models, Molecular ; Nuclear Proteins/*chemistry/genetics/*metabolism ; Protein Binding ; Protein Conformation ; Protein Structure, Tertiary ; Substrate Specificity
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  • 19
    Publication Date: 2010-03-17
    Description: Demethylation at distinct lysine residues in histone H3 by lysine-specific demethylase 1 (LSD1) causes either gene repression or activation. As a component of co-repressor complexes, LSD1 contributes to target gene repression by removing mono- and dimethyl marks from lysine 4 of histone H3 (H3K4). In contrast, during androgen receptor (AR)-activated gene expression, LSD1 removes mono- and dimethyl marks from lysine 9 of histone H3 (H3K9). Yet, the mechanisms that control this dual specificity of demethylation are unknown. Here we show that phosphorylation of histone H3 at threonine 6 (H3T6) by protein kinase C beta I (PKCbeta(I), also known as PRKCbeta) is the key event that prevents LSD1 from demethylating H3K4 during AR-dependent gene activation. In vitro, histone H3 peptides methylated at lysine 4 and phosphorylated at threonine 6 are no longer LSD1 substrates. In vivo, PKCbeta(I) co-localizes with AR and LSD1 on target gene promoters and phosphorylates H3T6 after androgen-induced gene expression. RNA interference (RNAi)-mediated knockdown of PKCbeta(I) abrogates H3T6 phosphorylation, enhances demethylation at H3K4, and inhibits AR-dependent transcription. Activation of PKCbeta(I) requires androgen-dependent recruitment of the gatekeeper kinase protein kinase C (PKC)-related kinase 1 (PRK1). Notably, increased levels of PKCbeta(I) and phosphorylated H3T6 (H3T6ph) positively correlate with high Gleason scores of prostate carcinomas, and inhibition of PKCbeta(I) blocks AR-induced tumour cell proliferation in vitro and cancer progression of tumour xenografts in vivo. Together, our data establish that androgen-dependent kinase signalling leads to the writing of the new chromatin mark H3T6ph, which in consequence prevents removal of active methyl marks from H3K4 during AR-stimulated gene expression.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Metzger, Eric -- Imhof, Axel -- Patel, Dharmeshkumar -- Kahl, Philip -- Hoffmeyer, Katrin -- Friedrichs, Nicolaus -- Muller, Judith M -- Greschik, Holger -- Kirfel, Jutta -- Ji, Sujuan -- Kunowska, Natalia -- Beisenherz-Huss, Christian -- Gunther, Thomas -- Buettner, Reinhard -- Schule, Roland -- England -- Nature. 2010 Apr 1;464(7289):792-6. doi: 10.1038/nature08839. Epub 2010 Mar 14.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Urologische Klinik/Frauenklinik und Zentrale Klinische Forschung, Klinikum der Universitat Freiburg, Breisacherstrasse 66, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20228790" target="_blank"〉PubMed〈/a〉
    Keywords: Androgens/metabolism/pharmacology ; Animals ; Cell Division/drug effects ; Cell Line, Tumor ; Chromatin/metabolism ; Gene Expression Regulation/drug effects ; Gene Knockdown Techniques ; Histone Demethylases/antagonists & inhibitors/*metabolism ; Histones/*chemistry/*metabolism ; Humans ; Lysine/chemistry/metabolism ; Male ; Methylation/drug effects ; Mice ; Mice, Nude ; Mice, SCID ; Phosphorylation/drug effects ; Phosphothreonine/metabolism ; Promoter Regions, Genetic/genetics ; Prostatic Neoplasms/enzymology/metabolism/pathology ; Protein Kinase C/antagonists & inhibitors/deficiency/genetics/*metabolism ; Protein Kinase C beta ; Signal Transduction/drug effects ; Xenograft Model Antitumor Assays
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 20
    Publication Date: 2014-12-04
    Description: Filamentous actin (F-actin) is the major protein of muscle thin filaments, and actin microfilaments are the main component of the eukaryotic cytoskeleton. Mutations in different actin isoforms lead to early-onset autosomal dominant non-syndromic hearing loss, familial thoracic aortic aneurysms and dissections, and multiple variations of myopathies. In striated muscle fibres, the binding of myosin motors to actin filaments is mainly regulated by tropomyosin and troponin. Tropomyosin also binds to F-actin in smooth muscle and in non-muscle cells and stabilizes and regulates the filaments there in the absence of troponin. Although crystal structures for monomeric actin (G-actin) are available, a high-resolution structure of F-actin is still missing, hampering our understanding of how disease-causing mutations affect the function of thin muscle filaments and microfilaments. Here we report the three-dimensional structure of F-actin at a resolution of 3.7 A in complex with tropomyosin at a resolution of 6.5 A, determined by electron cryomicroscopy. The structure reveals that the D-loop is ordered and acts as a central region for hydrophobic and electrostatic interactions that stabilize the F-actin filament. We clearly identify map density corresponding to ADP and Mg(2+) and explain the possible effect of prominent disease-causing mutants. A comparison of F-actin with G-actin reveals the conformational changes during filament formation and identifies the D-loop as their key mediator. We also confirm that negatively charged tropomyosin interacts with a positively charged groove on F-actin. Comparison of the position of tropomyosin in F-actin-tropomyosin with its position in our previously determined F-actin-tropomyosin-myosin structure reveals a myosin-induced transition of tropomyosin. Our results allow us to understand the role of individual mutations in the genesis of actin- and tropomyosin-related diseases and will serve as a strong foundation for the targeted development of drugs.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4477711/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4477711/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉von der Ecken, Julian -- Muller, Mirco -- Lehman, William -- Manstein, Dietmar J -- Penczek, Pawel A -- Raunser, Stefan -- R01 60635/PHS HHS/ -- R01 GM060635/GM/NIGMS NIH HHS/ -- R37HL036153/HL/NHLBI NIH HHS/ -- U54 094598/PHS HHS/ -- U54 GM094598/GM/NIGMS NIH HHS/ -- England -- Nature. 2015 Mar 5;519(7541):114-7. doi: 10.1038/nature14033. Epub 2014 Dec 1.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany. ; Institute for Biophysical Chemistry, Hannover Medical School, 30625 Hannover, Germany. ; Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts 02118, USA. ; Department of Biochemistry and Molecular Biology, The University of Texas, Houston Medical School, Houston, Texas 77030, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25470062" target="_blank"〉PubMed〈/a〉
    Keywords: Actins/*chemistry/genetics/*metabolism ; Adenosine Diphosphate/metabolism ; Animals ; Cryoelectron Microscopy ; Magnesium/metabolism ; Mice ; Models, Molecular ; Mutation/genetics ; Protein Conformation ; Rabbits ; Static Electricity ; Tropomyosin/*chemistry/genetics/*metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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