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active DNA demethylation

Federica Parodi, Roberta Carosio, Marco Ragusa, Cinzia Di Pietro, Marco Maugeri, Davide Barbagallo, Fabio Sallustio, Giorgio Allemanni, Maria Pia Pistillo, Ida Casciano, Alessandra Forlani, Francesco P Schena, Michele Purrello, Massimo Romani, Barbara Banelli
In neuroblastoma, the epigenetic landscape is more profoundly altered in aggressive compared to lower grade tumors and the concomitant hypermethylation of many genes, defined as "methylator phenotype", has been associated with poor outcome. DNA methylation can interfere with gene expression acting at distance through the methylation or demethylation of the regulatory regions of miRNAs. The multiplicity of miRNA targets may result in the simultaneous alteration of many biological pathways like cell proliferation, apoptosis, migration and differentiation...
October 14, 2016: Biochimica et Biophysica Acta
Xin Li, Yun Liu, Tal Salz, Kasper D Hansen, Andrew P Feinberg
DNA methylation at the 5-postion of cytosine (5mC) is an epigenetic modification that regulates gene expression and cellular plasticity in development and disease. The ten-eleven translocation (TET) gene family oxidizes 5mC to 5-hydroxymethylcytosine (5hmC), providing an active mechanism for DNA demethylation, and may also provide its own regulatory function. Here we applied oxidative bisulfite sequencing to generate whole-genome DNA methylation and hydroxymethylation maps at single-base resolution in paired human liver and lung normal and cancer...
October 13, 2016: Genome Research
Nathalie Dehne, Bernhard Brüne
Hypoxia, by activating transcription factors induces transcription of some genes but it also reduces mRNA synthesis by mechanisms that are poorly defined. Activation of human macrophages with interleukin (IL)-4 showed that up-regulation of some IL-4 target genes was reduced when macrophages were incubated at 1% oxygen. Hypoxia impaired induction of chemokine (CC motif) ligand 18 (CCL18), although IL-4-induced DNA binding of the transcription factor STAT6 remained intact. In contrast, induction of serine peptidase inhibitor, Kunitz type (SPINT)2, another IL-4/STAT6 target gene, was not affected by hypoxia...
October 11, 2016: Biochimica et Biophysica Acta
Jianing Zhong, Xianfeng Li, Wanshi Cai, Yan Wang, Shanshan Dong, Jie Yang, Jian'an Zhang, Nana Wu, Yuanyuan Li, Fengbiao Mao, Cheng Zeng, Jinyu Wu, Xingzhi Xu, Zhong Sheng Sun
The Ten Eleven Translocation 1 (TET1) protein is a DNA demethylase that regulates gene expression through altering statue of DNA methylation. However, recent studies have demonstrated that TET1 could modulate transcriptional expression independent of its DNA demethylation activity; yet, the detailed mechanisms underlying TET1's role in such transcriptional regulation remain not well understood. Here, we uncovered that Tet1 formed a chromatin complex with histone acetyltransferase Mof and scaffold protein Sin3a in mouse embryonic stem cells by integrative genomic analysis using publicly available ChIP-seq data sets and a series of in vitro biochemical studies in human cell lines...
October 12, 2016: Nucleic Acids Research
Moshe Szyf
5'-hydroxymethylcytosine (5hmC) is a variant of the common covalent epigenetic modification of DNA 5'-methylcytosine (5mC). Although the presence of this modified base in mammalian DNA has been recognized for several decades, it has recently gained center stage as a suspected intermediate in enzymatic active demethylation of 5mC. The role of 5hmC remains elusive in spite of a large body of studies. It is proposed that 5hmC is a variant of the 5mC epigenetic signal and is involved in epigenetic regulation of gene function...
October 13, 2016: Epigenomics
Ferdinand von Meyenn, Rebecca V Berrens, Simon Andrews, Fátima Santos, Amanda J Collier, Felix Krueger, Rodrigo Osorno, Wendy Dean, Peter J Rugg-Gunn, Wolf Reik
Primordial germ cell (PGC) development is characterized by global epigenetic remodeling, which resets genomic potential and establishes an epigenetic ground state. Here we recapitulate PGC specification in vitro from naive embryonic stem cells and characterize the early events of epigenetic reprogramming during the formation of the human and mouse germline. Following rapid de novo DNA methylation during priming to epiblast-like cells, methylation is globally erased in PGC-like cells. Repressive chromatin marks (H3K9me2/3) and transposable elements are enriched at demethylation-resistant regions, while active chromatin marks (H3K4me3 or H3K27ac) are more prominent at regions that demethylate faster...
October 10, 2016: Developmental Cell
B C Medeiros, A T Fathi, C D DiNardo, D A Pollyea, S M Chan, R Swords
Alterations to genes involved in cellular metabolism and epigenetic regulation are implicated in the pathogenesis of myeloid malignancies. Recurring mutations in isocitrate dehydrogenase (IDH) genes are detected in approximately 20% of adult patients with acute myeloid leukemia (AML) and 5% of adults with myelodysplastic syndromes (MDS). IDH proteins are homodimeric enzymes involved in diverse cellular processes, including adaptation to hypoxia, histone demethylation, and DNA modification. The IDH2 protein is localized in the mitochondria and is a critical component of the tricarboxylic acid (TCA, also called the 'citric acid' or Krebs) cycle...
October 10, 2016: Leukemia: Official Journal of the Leukemia Society of America, Leukemia Research Fund, U.K
Miho M Suzuki, Tomoko Mori, Noriyuki Satoh
The initiation of embryonic gene expression in ascidian embryos appears to be tightly regulated by the number of DNA replication cycles. DNA methylation is thought to contribute to the clock mechanism that counts the rounds of DNA replication. We used mass spectrometry and whole genome bisulfite sequencing to characterize DNA methylation changes that occur in early developmental stages of the ascidian, Ciona intestinalis. We found that global DNA methylation in early Ciona development was static, and a base-wise comparison between the genomes of consecutive developmental stages found no DNA demethylation that was related to zygotic gene activation...
October 5, 2016: Genomics
Hesbon Z Amenya, Chiharu Tohyama, Seiichiroh Ohsako
The aryl hydrocarbon receptor (Ahr) is a highly conserved nuclear receptor that plays an important role in the manifestation of toxicity induced by polycyclic aromatic hydrocarbons. As a xenobiotic sensor, Ahr is involved in chemical biotransformation through activation of drug metabolizing enzymes. The activated Ahr cooperates with coactivator complexes to induce epigenetic modifications at target genes. Thus, it is conceivable that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a potent Ahr ligand, may elicit robust epigenetic changes in vivo at the Ahr target gene cytochrome P450 1a1 (Cyp1a1)...
October 7, 2016: Scientific Reports
Megan Breski, Debasis Dey, Sara Obringer, Babu Sudhamalla, Kabirul Islam
Oxidative C-H hydroxylation of methyl groups, followed by their removal from DNA, RNA or histones, is an epigenetic process critical to transcriptional reprogramming and cell fate determination. This reaction is catalyzed by Fe(II)-dependent dioxygenases using the essential metabolite 2-ketoglutarate (2KG) as a cofactor. Given that the human genome encodes for more than 60 2KG-dependent dioxygenases, assigning their individual functions remains a significant challenge. Here we describe a protein-ligand interface engineering approach to break the biochemical degeneracy of these enzymes...
October 6, 2016: Journal of the American Chemical Society
Wei Zhang, Dongjie Han, Pin Wan, Pan Pan, Yanhua Cao, Yingle Liu, Kailang Wu, Jianguo Wu
DNA demethylation plays an essential role in the reactivation of Epstein-Barr virus (EBV) from latency infection. However, it is unclear how epigenetic modification is initiated in responding to stimuli. Here, we demonstrate that ERK/c-Jun signaling is involved in DNA demethylation of EBV immediate early (IE) gene Zta in response to 12-O-Tetradecanoylphorbol-13-acetate (TPA) stimulation. Remarkably, Ser73 phosphorylation of c-Jun facilitates Zta promoter demethylation and EBV reactivation, whereas knockdown of c-Jun attenuates Zta demethylation and viral reactivation...
October 6, 2016: Scientific Reports
Hisato Kobayashi, Tasuku Koike, Akihiko Sakashita, Keisuke Tanaka, Soichiro Kumamoto, Tomohiro Kono
Whole-genome shotgun bisulfite sequencing (WG-SBS) is currently the most powerful tool available for understanding genomewide cytosine methylation with single-base resolution; however, the high sequencing cost limits its widespread application, particularly for mammalian genomes. We mapped high- to low-coverage SBS short reads of mouse and human female developing germ cells to consensus sequences of repetitive elements that were multiplied in the respective host genome. This mapping strategy effectively identified active and evolutionarily young retrotransposon subfamilies and centromeric satellite repeats that were resistant to DNA demethylation during the investigated progressive stages of germ cell development...
October 3, 2016: Genes to Cells: Devoted to Molecular & Cellular Mechanisms
Seiichiro Kizaki, Tingting Zou, Yue Li, Yong-Woon Han, Yuki Suzuki, Yoshie Harada, Hiroshi Sugiyama
Tet (ten-eleven translocation) family proteins oxidize 5-methylcytosine (mC) to 5-hydroxymethylcytosine (hmC), 5-formylcytosine (fC), and 5-carboxycytosine (caC), and are suggested to be involved in the active DNA demethylation pathway. In this study, we reconstituted positioned mononucleosomes using CpG-methylated 382 bp DNA containing the Widom 601 sequence and recombinant histone octamer, and subjected the nucleosome to treatment with Tet1 protein. The sites of oxidized methylcytosine were identified by bisulfite sequencing...
September 30, 2016: Chemistry: a European Journal
Hiroshi Mihara, Nobuhiro Suzuki, Jibran Sualeh Muhammad, Sohachi Nanjo, Takayuki Ando, Haruka Fujinami, Shinya Kajiura, Ayumu Hosokawa, Toshiro Sugiyama
BACKGROUND: Helicobacter pylori (HP) infection induces methylation silencing of specific genes in gastric epithelium. Various stimuli activate the nonselective cation channel TRPV4, which is expressed in gastric epithelium where it detects mechanical stimuli and promotes ATP release. As CpG islands in TRPV4 are methylated in HP-infected gastric epithelium, we evaluated HP infection-dependent changes in TRPV4 expression in gastric epithelium. MATERIALS AND METHODS: Human gastric biopsy samples, a human gastric cancer cell line (AGS), and a normal gastric epithelial cell line (GES-1) were used to detect TRPV4 mRNA and protein expression by RT-PCR and Western blotting, respectively...
September 30, 2016: Helicobacter
Luis G Rabaneda, Noelia Geribaldi-Doldán, Maribel Murillo-Carretero, Manuel Carrasco, José M Martínez-Salas, Cristina Verástegui, Carmen Castro
Hyperhomocysteinemia reduces neurogenesis in the adult mouse brain. Homocysteine (Hcy) inhibits postnatal neural progenitor cell (NPC) proliferation by specifically impairing the fibroblast growth factor receptor (FGFR)-Erk1/2-cyclin E signaling pathway. We demonstrate herein that the inhibition of FGFR-dependent NPC proliferation induced by Hcy is mediated by its capacity to alter the cellular methylation potential. Our results show that this alteration modified the expression pattern and activity of Sprouty2 (Spry2), a negative regulator of the above mentioned pathway...
September 26, 2016: Biochimica et Biophysica Acta
Xiao Huang, Guiqing Kong, Yan Li, Weiwei Zhu, Haixiao Xu, Xiaohua Zhang, Jiankui Li, Lipeng Wang, Zhongwen Zhang, Yaru Wu, Xiangyong Liu, Xiaozhi Wang
Decitabine (5-aza-2'-deoxycytidine, DAC) and 5-azacitidine (Aza), an inhibitor of DNA methyltransferases, possess a wide range of anti-metabolic and anti-cancer activities. This study examined the effects of DAC and Aza on inflammatory and oxidative injuries, as well as on glycocalyx and MAPK signaling pathways, in a LPS-stimulated ARDS mouse model. Results of ELISA revealed that DAC and Aza significantly inhibited the production of TNF-α and IL-1β and prevented LPS-induced elevation of myeloperoxidase and malondialdehyde levels in serum...
September 26, 2016: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Andrew D King, Kevin Huang, Liudmilla Rubbi, Shuo Liu, Cun-Yu Wang, Yinsheng Wang, Matteo Pellegrini, Guoping Fan
DNA methylation is one of a number of modes of epigenetic gene regulation. Here, we profile the DNA methylome, transcriptome, and global occupancy of histone modifications (H3K4me1, H3K4me3, H3K27me3, and H3K27ac) in a series of mouse embryonic stem cells (mESCs) with varying DNA methylation levels to study the effects of DNA methylation on deposition of histone modifications. We find that genome-wide DNA demethylation alters occupancy of histone modifications at both promoters and enhancers. This is reversed upon remethylation by Dnmt expression...
September 27, 2016: Cell Reports
Mélanie A Eckersley-Maslin, Valentine Svensson, Christel Krueger, Thomas M Stubbs, Pascal Giehr, Felix Krueger, Ricardo J Miragaia, Charalampos Kyriakopoulos, Rebecca V Berrens, Inês Milagre, Jörn Walter, Sarah A Teichmann, Wolf Reik
Mouse embryonic stem cells are dynamic and heterogeneous. For example, rare cells cycle through a state characterized by decondensed chromatin and expression of transcripts, including the Zscan4 cluster and MERVL endogenous retrovirus, which are usually restricted to preimplantation embryos. Here, we further characterize the dynamics and consequences of this transient cell state. Single-cell transcriptomics identified the earliest upregulated transcripts as cells enter the MERVL/Zscan4 state. The MERVL/Zscan4 transcriptional network was also upregulated during induced pluripotent stem cell reprogramming...
September 27, 2016: Cell Reports
Matteo Perino, Gert Jan C Veenstra
Chromatin structure is intimately connected with gene expression and cell identity. Here we review recent advances in the field and discuss how establishment of cell identity during development is accompanied by large-scale remodeling of the epigenetic landscape and how this remodeling drives and supports lineage specification and maintenance. We discuss maternal control of the early embryonic epigenetic landscape, selective usage of enhancer clusters via 3D chromatin contacts leading to activation of transcription factor networks, and conserved regulation of developmental pathways by specific DNA demethylation of key regulatory regions...
September 26, 2016: Developmental Cell
X Shawn Liu, Hao Wu, Xiong Ji, Yonatan Stelzer, Xuebing Wu, Szymon Czauderna, Jian Shu, Daniel Dadon, Richard A Young, Rudolf Jaenisch
Mammalian DNA methylation is a critical epigenetic mechanism orchestrating gene expression networks in many biological processes. However, investigation of the functions of specific methylation events remains challenging. Here, we demonstrate that fusion of Tet1 or Dnmt3a with a catalytically inactive Cas9 (dCas9) enables targeted DNA methylation editing. Targeting of the dCas9-Tet1 or -Dnmt3a fusion protein to methylated or unmethylated promoter sequences caused activation or silencing, respectively, of an endogenous reporter...
September 22, 2016: Cell
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