Suchergebnisse

GAGA is a nuclear protein encoded by the Trithorax-like gene in Drosophila that is expressed in at least two isoforms generated by alternative splicing. By means of its specific interaction with DNA, GAGA has been involved in several nuclear transactions including regulation of gene expression. Here we have studied the GAGA519 isoform as a transcription factor. In vitro, the transactivation domain has been assigned to the 93 C- terminal residues that correspond to a glutamine-rich domain (Q-domain). It presents an internal modular structure and acts independently of the rest of the protein. In vivo, in Drosophila SL2 cells, Q-domain can transactivate reporter genes either in the form of GAGA or Gal4BD-Q fusions, whereas a GAGA mutant deleted of the Q-domain cannot. Our results give support to the notion that GAGA can function as a transcription activating factor. ; This work was supported by Spanish Dirección General de Enzeñanza Superior Grant PB96-0812, European Union Grant FMRX-CT97-0109, and Comissió Interdepartamental de Recerca i InnovacióTecnològica (CIRIT) of the Generalitat de Catalunya Grant SGR97-55. This work was carried out in the context of the Centre de Referència en Biotecnologia of the CIRIT of the Generalitat de Catalunya ; Peer Reviewed

Mouse has been extensively used as a model organism in many studies to characterize biological pathways and drug effects and to mimic human diseases. Similar DNA sequences between both species facilitate these types of experiments. However, much less is known about the mouse epigenome, particularly for DNA methylation. Progress in delivering mouse DNA methylomes has been slow due to the currently available time-consuming and expensive methodologies. Following the great acceptance of the human DNA methylation microarrays, we have herein validated a newly developed DNA methylation microarray (Infinium Mouse Methylation BeadChip) that interrogates 280,754 unique CpG sites within the mouse genome. The CpGs included in the platform cover CpG Islands, shores, shelves and open sea sequences, and loci surrounding transcription start sites and gene bodies. From a functional standpoint, mouse ENCODE representative DNase hypersensitivity sites (rDHSs) and candidate cis-Regulatory Elements (cCREs) are also included. Herein, we show that the profiled mouse DNA methylation microarray provides reliable values among technical replicates; matched results from fresh frozen versus formalin-fixed samples; detects hemimethylated X-chromosome and imprinted CpG sites; and is able to determine CpG methylation changes in mouse cell lines treated with a DNA demethylating agent or upon genetic disruption of a DNA methyltransferase. Most important, using unsupervised hierarchical clustering and t-SNE approaches, the platform is able to classify all types of normal mouse tissues and organs. These data underscore the great features of the assessed microarray to obtain comprehensive DNA methylation profiles of the mouse genome. ; We thank the CERCA Programme/Generalitat de Catalunya for institutional support. This work was supported by the Health Department PERIS-project no. SLT/002/16/00374 and AGAUR-project no. 2017SGR1080 of the Catalan Government (Generalitat de Catalunya); Ministerio de Ciencia e Innovación (MCI), Agencia Estatal de Investigación (AEI), and European Regional Development Fund (ERDF) project no. RTI2018-094049-B-I00 and PID2020-117284RB-I00; the Cellex Foundation; Marie Sklodowska-Curie Fellowship no. 895979 from the European Commission (BNV); and 'la Caixa' Banking Foundation (LCF/PR/GN18/51140001). ; Peer Reviewed ; Postprint (published version)

Sirtuin 2 (SIRT2) is a member of a family of NAD+ -dependent histone deacetylases (HDAC) that play diverse roles in cellular metabolism and especially for aging process. SIRT2 is located in the nucleus, cytoplasm, and mitochondria, is highly expressed in the central nervous system (CNS), and has been reported to regulate a variety of processes including oxidative stress, genome integrity, and myelination. However, little is known about the role of SIRT2 in the nervous system specifically during aging. Here, we show that middle-aged, 13-month-old mice lacking SIRT2 exhibit locomotor dysfunction due to axonal degeneration, which was not present in young SIRT2 mice. In addition, these Sirt2-/- mice exhibit mitochondrial depletion resulting in energy failure, and redox dyshomeostasis. Our results provide a novel link between SIRT2 and physiological aging impacting the axonal compartment of the central nervous system, while supporting a major role for SIRT2 in orchestrating its metabolic regulation. This underscores the value of SIRT2 as a therapeutic target in the most prevalent neurodegenerative diseases that undergo with axonal degeneration associated with redox and energetic dyshomeostasis. ; This study was supported by grants from the Spanish Institute for Health Carlos III and 'Fondo Europeo de Desarrollo Regional (FEDER), Union Europea, una manera de hacer Europa' [FIS PI11/01043, FIS PI14/00410], the Autonomous Government of Catalonia [SGR 2014SGR1430] to A.P., The Spanish Institute for Health Carlos III and 'Fondo Europeo de Desarrollo Regional (FEDER), Union Europea, una manera de hacer Europa' [Miguel Servet program CP11/00080, CPII16/00016, FIS PI15/00857] to S.F. and the Center for Biomedical Research on Rare Diseases (CIBERER) to M.R., and the Spanish Institute for Health Carlos III and FEDER funds from European Union ('A way to build Europe') [FIS grants PI14/01115, PI13/00584, and PI14/00328], Foundation La Marató de TV3 [345/C/2014], and the Autonomous Government of Catalonia [2014SGR168] to M.J., M.P.O., and R.P. The studies conducted at the Chromatin Biology Laboratory were supported by the Spanish Ministry of Economy and Competitiveness‐MINECO [SAF2011‐25860, SAF2014‐55964R] to A.V.

Sirtuin 2 (SIRT2) is a member of a family of NAD+-dependent histone deacetylases (HDAC) that play diverse roles in cellular metabolism and especially for aging process. SIRT2 is located in the nucleus, cytoplasm, and mitochondria, is highly expressed in the central nervous system (CNS), and has been reported to regulate a variety of processes including oxidative stress, genome integrity, and myelination. However, little is known about the role of SIRT2 in the nervous system specifically during aging. Here, we show that middle-aged, 13-month-old mice lacking SIRT2 exhibit locomotor dysfunction due to axonal degeneration, which was not present in young SIRT2 mice. In addition, these Sirt2−/− mice exhibit mitochondrial depletion resulting in energy failure, and redox dyshomeostasis. Our results provide a novel link between SIRT2 and physiological aging impacting the axonal compartment of the central nervous system, while supporting a major role for SIRT2 in orchestrating its metabolic regulation. This underscores the value of SIRT2 as a therapeutic target in the most prevalent neurodegenerative diseases that undergo with axonal degeneration associated with redox and energetic dyshomeostasis. ; This study was supported by grants from the Spanish Institute for Health Carlos III and 'Fondo Europeo de Desarrollo Regional (FEDER), Union Europea, una manera de hacer Europa' [FIS PI11/01043, FIS PI14/00410], the Autonomous Government of Catalonia [SGR 2014SGR1430] to A.P., The Spanish Institute for Health Carlos III and 'Fondo Europeo de Desarrollo Regional (FEDER), Union Europea, una manera de hacer Europa' [Miguel Servet program CP11/00080, CPII16/00016, FIS PI15/ 00857] to S.F. and the Center for Biomedical Research on Rare Diseases (CIBERER) to M.R., and the Spanish Institute for Health Carlos III and FEDER funds from European Union ('A way to build Europe') [FIS grants PI14/01115, PI13/00584, and PI14/00328], Foundation La Marató de TV3 [345/C/2014], and the Autonomous Government of Catalonia [2014SGR168] to M.J., M.P.O., and R.P. The studies conducted at the Chromatin Biology Laboratory were supported by the Spanish Ministry of Economy and Competitiveness-MINECO [SAF2011-25860, SAF2014-55964R] to A.V.

HP1 is a structural component of heterochromatin. Mammalian HP1 isoforms HP1α, HP1β, and HP1γ play different roles in genome stability, but their precise role in heterochromatin structure is unclear. Analysis of Hp1α-/-, Hp1β-/-, and Hp1γ-/- MEFs show that HP1 proteins have both redundant and unique functions within pericentric heterochromatin (PCH) and also act globally throughout the genome. HP1α confines H4K20me3 and H3K27me3 to regions within PCH, while its absence results in a global hyper-compaction of chromatin associated with a specific pattern of mitotic defects. In contrast, HP1β is functionally associated with Suv4-20h2 and H4K20me3, and its loss induces global chromatin decompaction and an abnormal enrichment of CTCF in PCH and other genomic regions. Our work provides insight into the roles of HP1 proteins in heterochromatin structure and genome stability. ; This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) (SAF2011-25860 and SAF2014-55964R to A.V.) and cofunded by FEDER funds/European Regional Development Fund (ERDF)-a way to build Europe, the Catalan Government Agency AGAUR (2009SGR-914 and 2014SGR-400 to A.V.), HGINJ (to L.S.), Deutsche Forschungsgemeinschaft (SFB1064 to G.S.), and the Canadian Institutes of Health Research (CIHR) (MOP-97878 to J.A.).

Sirtuins are key players of metabolic stress response. Originally described as deacetylases, some sirtuins also exhibit poorly understood mono-adenosine 5'-diphosphate (ADP)-ribosyltransferase (mADPRT) activity. We report that the deacetylase SirT7 is a dual sirtuin, as it also features auto-mADPRT activity. SirT7 mADPRT occurs at a previously undefined active site, and its abrogation alters SirT7 chromatin distribution. We identify an epigenetic pathway by which ADP-ribosyl-SirT7 is recognized by the ADP-ribose reader mH2A1.1 under glucose starvation, inducing SirT7 relocalization to intergenic regions. SirT7 promotes mH2A1 enrichment in a subset of nearby genes, many of them involved in second messenger signaling, resulting in their specific up- or down-regulation. The expression profile of these genes under calorie restriction is consistently abrogated in SirT7-deficient mice, resulting in impaired activation of autophagy. Our work provides a novel perspective on sirtuin duality and suggests a role for SirT7/mH2A1.1 axis in glucose homeostasis and aging. ; This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) (SAF2011-25860, SAF2014-55964R, and SAF2017-88975R to A.V.; SAF2016-77830R to M.O.; and CTQ2016-80364-P to E.S.) and cofunded by FEDER funds/European Regional Development Fund (ERDF)–A Way to Build Europe, the Catalan government agency AGAUR (2014-SGR400 and 2017-SGR148 to A.V. and 2017-SGR595 to E.S.), a grant from Rutgers Human Genetics Institute of New Jersey (J.T. and L.S.), the German Center for Cardiovascular Research (DZHK), and the Deutsche Forschungsgemeinschaft (DFG SFB TRR81 A02 and SFB 1213 TP B02 to A.I. and T.B.).

Sirtuins are NAD+-dependent deacetylases that facilitate cellular stress response. They include SirT6, which protects genome stability and regulates metabolic homeostasis through gene silencing, and whose loss induces an accelerated aging phenotype directly linked to hyperactivation of the NF-κB pathway. Here we show that SirT6 binds to the H3K9me3-specific histone methyltransferase Suv39h1 and induces monoubiquitination of conserved cysteines in the PRE-SET domain of Suv39h1. Following activation of NF-κB signaling Suv39h1 is released from the IκBα locus, subsequently repressing the NF-κB pathway. We propose that SirT6 attenuates the NF-κB pathway through IκBα upregulation via cysteine monoubiquitination and chromatin eviction of Suv39h1. We suggest a mechanism based on SirT6-mediated enhancement of a negative feedback loop that restricts the NF-κB pathway. ; This work was supported by the Fundació La Marató de TV3 (20133810 to A.V.), the Spanish Ministry of Economy and competitiveness-MINECO (SAF2011-25860, SAF2014-55964R to A.V.) confunded by FEDER funds/European Regional Development Fund (ERDF)-a way to Build Europe, and the Catalan government agency AGAUR (2009-SGR-914 to A.V.) The IDIBELL Proteomics Unit belongs to ProteoRed, PRB2-ISCIII, and is supported by grant PT13/0001/0033 and Cellex Foundation. S.B.B. is the recipient of a 13FIS037 fellowship.

Altres ajuts: Fundación Científica de la AECC (to R.G.U.); Fundación Ramón Areces (to M.F.F); FICYT (to E.G.T., M.G.G., A.C.); Asturias Regional Government [GRUPIN14-052 to M.F.F.]; Gobierno del Principado de Asturias, PCTI-Plan de Ciencia, Tecnología e Innovación co-funding Fondos FEDER (grant number IDI/2018/146 to M.F.F. and IDI/2018/144 to C.L.); Asociación Española Contra el Cáncer [AECC-CI-2015]; P.M. acknowledges financial support from The Obra Social La Caixa-Fundaciò Josep Carreras. P.M. an investigator from the Spanish Cell Therapy cooperative network (TERCEL). The IUOPA is supported by the Obra Social Liberbank-Cajastur, Spain. ; Histone H4 acetylation at Lysine 16 (H4K16ac) is a key epigenetic mark involved in gene regulation, DNA repair and chromatin remodeling, and though it is known to be essential for embryonic development, its role during adult life is still poorly understood. Here we show that this lysine is massively hyperacetylated in peripheral neutrophils. Genome-wide mapping of H4K16ac in terminally differentiated blood cells, along with functional experiments, supported a role for this histone post-translational modification in the regulation of cell differentiation and apoptosis in the hematopoietic system. Furthermore, in neutrophils, H4K16ac was enriched at specific DNA repeats. These DNA regions presented an accessible chromatin conformation and were associated with the cleavage sites that generate the 50 kb DNA fragments during the first stages of programmed cell death. Our results thus suggest that H4K16ac plays a dual role in myeloid cells as it not only regulates differentiation and apoptosis, but it also exhibits a non-canonical structural role in poising chromatin for cleavage at an early stage of neutrophil cell death.

Histone H4 acetylation at Lysine 16 (H4K16ac) is a key epigenetic mark involved in gene regulation, DNA repair and chromatin remodeling, and though it is known to be essential for embryonic development, its role during adult life is still poorly understood. Here we show that this lysine is massively hyperacetylated in peripheral neutrophils. Genome-wide mapping of H4K16ac in terminally differentiated blood cells, along with functional experiments, supported a role for this histone post-translational modification in the regulation of cell differentiation and apoptosis in the hematopoietic system. Furthermore, in neutrophils, H4K16ac was enriched at specific DNA repeats. These DNA regions presented an accessible chromatin conformation and were associated with the cleavage sites that generate the 50 kb DNA fragments during the first stages of programmed cell death. Our results thus suggest that H4K16ac plays a dual role in myeloid cells as it not only regulates differentiation and apoptosis, but it also exhibits a non-canonical structural role in poising chromatin for cleavage at an early stage of neutrophil cell death. ; Plan Nacional de I+D+I co-funding FEDER [PI15/00892 and PI18/01527 to M.F.F. and A.F.F.; PI16/01318 and PI14/01244 to C.L.]; ISCIII-Subdireccion General de Evaluacion y Fomento de la Investigacion, and Plan Nacional de I+D+I 2008–2011/FEDER [CP11/00131 to A.F.F.]; IUOPA (to G.F.B. and M.I.S.); Fundacion Cientifica de la AECC (to R.G.U.); Ministry of Economy and Competitiveness Juan de la Cierva postdoctoral fellowships [FJCI-2015-26965 to J.R.T., IJCI-2015- 23316 to V.L.]; Fundacion Ramon Areces (to M.F.F); FICYT (to E.G.T., M.G.G., A.C.); Asturias Regional Government [GRUPIN14-052 to M.F.F.]; Gobierno del Principado de Asturias, PCTI-Plan de Ciencia, Tecnologia e Innovacion co-funding Fondos FEDER (grant number IDI/2018/146 to M.F.F. and IDI/2018/144 to C.L.); Deutsche Forschungsgemeinschaft (DFG) [SFB960 to A.V.G., R.D.]; European Research Council [CoG-2014-646903]; Spanish Ministry of Economy and Competitiveness [SAF-SAF2013-43065 to P.M.]; Asociacion Española Contra el Cancer [AECC-CI-2015]; FERO Foundation, and the ISCIII [PI14-01191 to C.B.]; P.M. acknowledges financial support from The Obra Social La Caixa Fundacio Josep Carreras and The Generalitat de Catalunya (SGR330). P.M. an investigator from the Spanish Cell Therapy cooperative network (TERCEL). The IUOPA is supported by the Obra Social Liberbank-Cajastur, Spain. Funding for open access charge: Plan Nacional de I+D+I co-funding FEDER [PI18/01527].