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Wadhwa N, Kapoor S, Kapoor M. Arabidopsis T-DNA mutants affected in TRDMT1/DNMT2 show differential protein synthesis and compromised stress tolerance. FEBS J 2024; 291:92-113. [PMID: 37584564 DOI: 10.1111/febs.16935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 07/18/2023] [Accepted: 08/14/2023] [Indexed: 08/17/2023]
Abstract
TRDMT1/DNMT2 belongs to the conserved family of nucleic acid methyltransferases. Unlike the animal systems, studies on TRDMT1/DNMT2 in land plants have been limited. We show that TRDMT1/DNMT2 is strongly conserved in the green lineage. Studies in mosses have previously shown that TRDMT1/DNMT2 plays a crucial role in modulating molecular networks involved in stress perception and signalling and in transcription/stability of specific tRNAs under stress. To gain deeper insight into its biological roles in a flowering plant, we examined more closely the previously reported Arabidopsis SALK_136635C line deficient in TRDMT1/DNMT2 function [Goll MG et al. (2006) Science 311, 395-398]. RNAs derived from Arabidopsis Dnmt2-deficient plants lacked m5 C38 in tRNAAsp . In this study, by transient expression assays we show that Arabidopsis TRDMT1/DNMT2 is distributed in the nucleus, cytoplasm and RNA-processing bodies, suggesting a role for TRDMT1/DNMT2 in RNA metabolic processes possibly by shuttling between cellular compartments. Bright-field and high-resolution SEM and qPCR analysis reveal roles of TRDMT1/DNMT2 in proper growth and developmental progression. Quantitative proteome analysis by LC-MS/MS coupled with qPCR shows AtTRDMT1/AtDNMT2 function to be crucial for protein synthesis and cellular homeostasis via housekeeping roles and proteins with poly-Asp stretches and RNA pol II activity on selected genes are affected in attrdmt1/atdnmt2. This shift in metabolic pathways primes the mutant plants to become increasingly sensitive to oxidative and osmotic stress. Taken together, our study sheds light on the mechanistic role of TRDMT1/DNMT2 in a flowering plant.
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Affiliation(s)
- Nikita Wadhwa
- University School of Biotechnology, Guru Gobind Singh Indraprastha University, New Delhi, India
| | - Sanjay Kapoor
- University School of Biotechnology, Guru Gobind Singh Indraprastha University, New Delhi, India
- Interdisciplinary Centre for Plant Genomics and Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | - Meenu Kapoor
- University School of Biotechnology, Guru Gobind Singh Indraprastha University, New Delhi, India
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2
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Mascarenhas Dos Santos AC, Julian AT, Liang P, Juárez O, Pombert JF. Telomere-to-Telomere genome assemblies of human-infecting Encephalitozoon species. BMC Genomics 2023; 24:237. [PMID: 37142951 PMCID: PMC10158259 DOI: 10.1186/s12864-023-09331-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 04/25/2023] [Indexed: 05/06/2023] Open
Abstract
BACKGROUND Microsporidia are diverse spore forming, fungal-related obligate intracellular pathogens infecting a wide range of hosts. This diversity is reflected at the genome level with sizes varying by an order of magnitude, ranging from less than 3 Mb in Encephalitozoon species (the smallest known in eukaryotes) to more than 50 Mb in Edhazardia spp. As a paradigm of genome reduction in eukaryotes, the small Encephalitozoon genomes have attracted much attention with investigations revealing gene dense, repeat- and intron-poor genomes characterized by a thorough pruning of molecular functions no longer relevant to their obligate intracellular lifestyle. However, because no Encephalitozoon genome has been sequenced from telomere-to-telomere and since no methylation data is available for these species, our understanding of their overall genetic and epigenetic architectures is incomplete. METHODS In this study, we sequenced the complete genomes from telomere-to-telomere of three human-infecting Encephalitozoon spp. -E. intestinalis ATCC 50506, E. hellem ATCC 50604 and E. cuniculi ATCC 50602- using short and long read platforms and leveraged the data generated as part of the sequencing process to investigate the presence of epigenetic markers in these genomes. We also used a mixture of sequence- and structure-based computational approaches, including protein structure prediction, to help identify which Encephalitozoon proteins are involved in telomere maintenance, epigenetic regulation, and heterochromatin formation. RESULTS The Encephalitozoon chromosomes were found capped by TTAGG 5-mer telomeric repeats followed by telomere associated repeat elements (TAREs) flanking hypermethylated ribosomal RNA (rRNA) gene loci featuring 5-methylcytosines (5mC) and 5-hemimethylcytosines (5hmC), themselves followed by lesser methylated subtelomeres and hypomethylated chromosome cores. Strong nucleotide biases were identified between the telomeres/subtelomeres and chromosome cores with significant changes in GC/AT, GT/AC and GA/CT contents. The presence of several genes coding for proteins essential to telomere maintenance, epigenetic regulation, and heterochromatin formation was further confirmed in the Encephalitozoon genomes. CONCLUSION Altogether, our results strongly support the subtelomeres as sites of heterochromatin formation in Encephalitozoon genomes and further suggest that these species might shutdown their energy-consuming ribosomal machinery while dormant as spores by silencing of the rRNA genes using both 5mC/5hmC methylation and facultative heterochromatin formation at these loci.
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Affiliation(s)
| | | | - Pingdong Liang
- Department of Biology, Illinois Institute of Technology, Chicago, IL, USA
| | - Oscar Juárez
- Department of Biology, Illinois Institute of Technology, Chicago, IL, USA
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3
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Zimmermann RA, Fischer TR, Schwickert M, Nidoieva Z, Schirmeister T, Kersten C. Chemical Space Virtual Screening against Hard-to-Drug RNA Methyltransferases DNMT2 and NSUN6. Int J Mol Sci 2023; 24:ijms24076109. [PMID: 37047081 PMCID: PMC10094593 DOI: 10.3390/ijms24076109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 02/20/2023] [Accepted: 03/22/2023] [Indexed: 04/14/2023] Open
Abstract
Targeting RNA methyltransferases with small molecules as inhibitors or tool compounds is an emerging field of interest in epitranscriptomics and medicinal chemistry. For two challenging RNA methyltransferases that introduce the 5-methylcytosine (m5C) modification in different tRNAs, namely DNMT2 and NSUN6, an ultra-large commercially available chemical space was virtually screened by physicochemical property filtering, molecular docking, and clustering to identify new ligands for those enzymes. Novel chemotypes binding to DNMT2 and NSUN6 with affinities down to KD,app = 37 µM and KD,app = 12 µM, respectively, were identified using a microscale thermophoresis (MST) binding assay. These compounds represent the first molecules with a distinct structure from the cofactor SAM and have the potential to be developed into activity-based probes for these enzymes. Additionally, the challenges and strategies of chemical space docking screens with special emphasis on library focusing and diversification are discussed.
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Affiliation(s)
- Robert A Zimmermann
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University, Staudingerweg 5, 55128 Mainz, Germany
| | - Tim R Fischer
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University, Staudingerweg 5, 55128 Mainz, Germany
| | - Marvin Schwickert
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University, Staudingerweg 5, 55128 Mainz, Germany
| | - Zarina Nidoieva
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University, Staudingerweg 5, 55128 Mainz, Germany
| | - Tanja Schirmeister
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University, Staudingerweg 5, 55128 Mainz, Germany
| | - Christian Kersten
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University, Staudingerweg 5, 55128 Mainz, Germany
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4
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Wagner A, Schosserer M. The epitranscriptome in ageing and stress resistance: A systematic review. Ageing Res Rev 2022; 81:101700. [PMID: 35908668 DOI: 10.1016/j.arr.2022.101700] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/15/2022] [Accepted: 07/25/2022] [Indexed: 01/31/2023]
Abstract
Modifications of RNA, collectively called the "epitranscriptome", might provide novel biomarkers and innovative targets for interventions in geroscience but are just beginning to be studied in the context of ageing and stress resistance. RNA modifications modulate gene expression by affecting translation initiation and speed, miRNA binding, RNA stability, and RNA degradation. Nonetheless, the precise underlying molecular mechanisms and physiological consequences of most alterations of the epitranscriptome are still only poorly understood. We here systematically review different types of modifications of rRNA, tRNA and mRNA, the methodology to analyze them, current challenges in the field, and human disease associations. Furthermore, we compiled evidence for a connection between individual enzymes, which install RNA modifications, and lifespan in yeast, worm and fly. We also included resistance to different stressors and competitive fitness as search criteria for genes potentially relevant to ageing. Promising candidates identified by this approach include RCM1/NSUN5, RRP8, and F33A8.4/ZCCHC4 that introduce base methylations in rRNA, the methyltransferases DNMT2 and TRM9/ALKBH8, as well as factors involved in the thiolation or A to I editing in tRNA, and finally the m6A machinery for mRNA.
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Affiliation(s)
- Anja Wagner
- Institute of Molecular Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Markus Schosserer
- Institute of Molecular Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria; Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria; Austrian Cluster for Tissue Regeneration, Vienna, Austria.
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5
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Jiang W, Tan XY, Li JM, Yu P, Dong M. DNA Methylation: A Target in Neuropathic Pain. Front Med (Lausanne) 2022; 9:879902. [PMID: 35872752 PMCID: PMC9301322 DOI: 10.3389/fmed.2022.879902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 06/06/2022] [Indexed: 11/13/2022] Open
Abstract
Neuropathic pain (NP), caused by an injury or a disease affecting the somatosensory nervous system of the central and peripheral nervous systems, has become a global health concern. Recent studies have demonstrated that epigenetic mechanisms are among those that underlie NP; thus, elucidating the molecular mechanism of DNA methylation is crucial to discovering new therapeutic methods for NP. In this review, we first briefly discuss DNA methylation, demethylation, and the associated key enzymes, such as methylases and demethylases. We then discuss the relationship between NP and DNA methylation, focusing on DNA methyltransferases including methyl-CpG-binding domain (MBD) family proteins and ten-eleven translocation (TET) enzymes. Based on experimental results of neuralgia in animal models, the mechanism of DNA methylation-related neuralgia is summarized, and useful targets for early drug intervention in NP are discussed.
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Affiliation(s)
- Wei Jiang
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Xuan-Yu Tan
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China
| | - Jia-Ming Li
- Department of Emergency, The First Hospital of Jilin University, Changchun, China
| | - Peng Yu
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, China
- *Correspondence: Peng Yu
| | - Ming Dong
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
- Ming Dong
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6
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Huang ZX, Li J, Xiong QP, Li H, Wang ED, Liu RJ. Position 34 of tRNA is a discriminative element for m5C38 modification by human DNMT2. Nucleic Acids Res 2021; 49:13045-13061. [PMID: 34871455 PMCID: PMC8682788 DOI: 10.1093/nar/gkab1148] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 10/05/2021] [Accepted: 11/03/2021] [Indexed: 12/05/2022] Open
Abstract
Dnmt2, a member of the DNA methyltransferase superfamily, catalyzes the formation of 5-methylcytosine at position 38 in the anticodon loop of tRNAs. Dnmt2 regulates many cellular biological processes, especially the production of tRNA-derived fragments and intergenerational transmission of paternal metabolic disorders to offspring. Moreover, Dnmt2 is closely related to human cancers. The tRNA substrates of mammalian Dnmt2s are mainly detected using bisulfite sequencing; however, we lack supporting biochemical data concerning their substrate specificity or recognition mechanism. Here, we deciphered the tRNA substrates of human DNMT2 (hDNMT2) as tRNAAsp(GUC), tRNAGly(GCC) and tRNAVal(AAC). Intriguingly, for tRNAAsp(GUC) and tRNAGly(GCC), G34 is the discriminator element; whereas for tRNAVal(AAC), the inosine modification at position 34 (I34), which is formed by the ADAT2/3 complex, is the prerequisite for hDNMT2 recognition. We showed that the C32U33(G/I)34N35 (C/U)36A37C38 motif in the anticodon loop, U11:A24 in the D stem, and the correct size of the variable loop are required for Dnmt2 recognition of substrate tRNAs. Furthermore, mammalian Dnmt2s possess a conserved tRNA recognition mechanism.
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MESH Headings
- 5-Methylcytosine/metabolism
- Adenosine Deaminase/genetics
- Adenosine Deaminase/metabolism
- Animals
- Anticodon/genetics
- Anticodon/metabolism
- Base Sequence
- DNA (Cytosine-5-)-Methyltransferases/chemistry
- DNA (Cytosine-5-)-Methyltransferases/genetics
- DNA (Cytosine-5-)-Methyltransferases/metabolism
- HEK293 Cells
- HeLa Cells
- Humans
- Inosine/metabolism
- Mice
- Models, Molecular
- NIH 3T3 Cells
- Nucleic Acid Conformation
- Protein Binding
- RNA, Transfer/chemistry
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- RNA, Transfer, Asp/chemistry
- RNA, Transfer, Asp/genetics
- RNA, Transfer, Asp/metabolism
- RNA, Transfer, Gly/chemistry
- RNA, Transfer, Gly/genetics
- RNA, Transfer, Gly/metabolism
- RNA, Transfer, Val/chemistry
- RNA, Transfer, Val/genetics
- RNA, Transfer, Val/metabolism
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- Substrate Specificity
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Affiliation(s)
- Zhi-Xuan Huang
- State Key Laboratory of Molecular Biology, Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100039, China
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Hua Xia Road, Shanghai 201210, China
| | - Jing Li
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Hua Xia Road, Shanghai 201210, China
| | - Qing-Ping Xiong
- State Key Laboratory of Molecular Biology, Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100039, China
| | - Hao Li
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Hua Xia Road, Shanghai 201210, China
| | - En-Duo Wang
- State Key Laboratory of Molecular Biology, Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100039, China
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Hua Xia Road, Shanghai 201210, China
| | - Ru-Juan Liu
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Hua Xia Road, Shanghai 201210, China
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7
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Abstract
Long noncoding RNAs exceeding a length of 200 nucleotides play an important role in ensuring cell functions and proper organism development by interacting with cellular compounds such as miRNA, mRNA, DNA and proteins. However, there is an additional level of lncRNA regulation, called lncRNA epigenetics, in gene expression control. In this review, we describe the most common modified nucleosides found in lncRNA, 6-methyladenosine, 5-methylcytidine, pseudouridine and inosine. The biosynthetic pathways of these nucleosides modified by the writer, eraser and reader enzymes are important to understanding these processes. The characteristics of the individual methylases, pseudouridine synthases and adenine-inosine editing enzymes and the methods of lncRNA epigenetics for the detection of modified nucleosides, as well as the advantages and disadvantages of these methods, are discussed in detail. The final sections are devoted to the role of modifications in the most abundant lncRNAs and their functions in pathogenic processes.
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Affiliation(s)
| | - Jan Wrzesinski
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland;
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8
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Nai YS, Huang YC, Yen MR, Chen PY. Diversity of Fungal DNA Methyltransferases and Their Association With DNA Methylation Patterns. Front Microbiol 2021; 11:616922. [PMID: 33552027 PMCID: PMC7862722 DOI: 10.3389/fmicb.2020.616922] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/28/2020] [Indexed: 11/24/2022] Open
Abstract
DNA methyltransferases (DNMTs) are a group of proteins that catalyze DNA methylation by transferring a methyl group to DNA. The genetic variation in DNMTs results in differential DNA methylation patterns associated with various biological processes. In fungal species, DNMTs and their DNA methylation profiles were found to be very diverse and have gained many research interests. We reviewed fungal DNMTs in terms of their biological functions, protein domain structures, and their associated epigenetic regulations compared to those known in plant and animal systems. In addition, we summarized recent reports on potential RNA-directed DNA methylation (RdDM) related to DNMT5 in fungi. We surveyed up to 40 fungal species with published genome-wide DNA methylation profiles (methylomes) and presented the associations between the specific patterns of fungal DNA methylation and their DNMTs based on a phylogenetic tree of protein domain structures. For example, the main DNMTs in Basidiomycota, DNMT1 with RFD domain + DNMT5, contributing to CG methylation preference, were distinct from RID + Dim-2 in Ascomycota, resulting in a non-CG methylation preference. Lastly, we revealed that the dynamic methylation involved in fungal life stage changes was particularly low in mycelium and DNA methylation was preferentially located in transposable elements (TEs). This review comprehensively discussed fungal DNMTs and methylomes and their connection with fungal development and taxonomy to present the diverse usages of DNA methylation in fungal genomes.
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Affiliation(s)
- Yu-Shin Nai
- Department of Entomology, National Chung Hsing University, Taichung, Taiwan.,Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Yu-Chun Huang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.,Bioinformatics Program, Taiwan International Graduate Program, National Taiwan University, Taipei, Taiwan.,Bioinformatics Program, Institute of Information Science, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan
| | - Ming-Ren Yen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Pao-Yang Chen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
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Cuypers B, Dumetz F, Meysman P, Laukens K, De Muylder G, Dujardin JC, Domagalska MA. The Absence of C-5 DNA Methylation in Leishmania donovani Allows DNA Enrichment from Complex Samples. Microorganisms 2020; 8:E1252. [PMID: 32824654 DOI: 10.3390/microorganisms8081252] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 08/12/2020] [Accepted: 08/12/2020] [Indexed: 11/21/2022] Open
Abstract
Cytosine C5 methylation is an important epigenetic control mechanism in a wide array of eukaryotic organisms and generally carried out by proteins of the C-5 DNA methyltransferase family (DNMTs). In several protozoans, the status of this mechanism remains elusive, such as in Leishmania, the causative agent of the disease leishmaniasis in humans and a wide array of vertebrate animals. In this work, we showed that the Leishmania donovani genome contains a C-5 DNA methyltransferase (DNMT) from the DNMT6 subfamily, whose function is still unclear, and verified its expression at the RNA level. We created viable overexpressor and knock-out lines of this enzyme and characterized their genome-wide methylation patterns using whole-genome bisulfite sequencing, together with promastigote and amastigote control lines. Interestingly, despite the DNMT6 presence, we found that methylation levels were equal to or lower than 0.0003% at CpG sites, 0.0005% at CHG sites, and 0.0126% at CHH sites at the genomic scale. As none of the methylated sites were retained after manual verification, we conclude that there is no evidence for DNA methylation in this species. We demonstrated that this difference in DNA methylation between the parasite (no detectable DNA methylation) and the vertebrate host (DNA methylation) allowed enrichment of parasite vs. host DNA using methyl-CpG-binding domain columns, readily available in commercial kits. As such, we depleted methylated DNA from mixes of Leishmania promastigote and amastigote DNA with human DNA, resulting in average Leishmania:human enrichments from 62× up to 263×. These results open a promising avenue for unmethylated DNA enrichment as a pre-enrichment step before sequencing Leishmania clinical samples.
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10
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du Preez PH, Breeds K, Burger NFV, Swiegers HW, Truter JC, Botha AM. DNA Methylation and Demethylation Are Regulated by Functional DNA Methyltransferases and DnTET Enzymes in Diuraphis noxia. Front Genet 2020; 11:452. [PMID: 32655611 PMCID: PMC7324797 DOI: 10.3389/fgene.2020.00452] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/14/2020] [Indexed: 12/31/2022] Open
Abstract
Aphids are economically important insect pests of crops worldwide. Despite resistant varieties being available, resistance is continuously challenged and eventually broken down, posing a threat to food security. In the current study, the epigenome of two related Russian wheat aphid (Diuraphis noxia, Kurdjumov) biotypes (i.e., SA1 and SAM) that differ in virulence was investigated to elucidate its role in virulence in this species. Whole genome bisulfite sequencing covered a total of 6,846,597,083 cytosine bases for SA1 and 7,397,965,699 cytosine bases for SAM, respectively, of which a total of 70,861,462 bases (SA1) and 74, 073,939 bases (SAM) were methylated, representing 1.126 ± 0.321% (SA1) and 1.105 ± 0.295% (SAM) methylation in their genomes. The sequence reads were analyzed for contexts of DNA methylation and the results revealed that RWA has methylation in all contexts (CpG, CHG and CHH), with the majority of methylation within the CpG context (± 5.19%), while the other contexts show much lower levels of methylation (CHG - ± 0.27%; CHH - ± 0.34%). The top strand was slightly (0.02%) more methylated than the bottom strand. Of the 35,493 genes that mapped, we also analyzed the contexts of methylation of each of these and found that the CpG methylation was much higher in genic regions than in intergenic regions. The CHG and CHH levels did not differ between genic and intergenic regions. The exonic regions of genes were more methylated (±0.56%) than the intronic regions. We also measured the 5mC and 5hmC levels between the aphid biotypes, and found little difference in 5mC levels between the biotypes, but much higher levels of 5hmC in the virulent SAM. RWA had two homologs of each of the DNA methyltransferases 1 (DNMT1a and DNMT1b) and DNMT3s (DNMT3a and DNMT3b), but only a single DNMT2, with only the expression of DNMT3 that differed significantly between the two RWA biotypes. RWA has a single ortholog of Ten eleven translocase (DnTET) in the genome. Feeding studies show that the more virulent RWA biotype SAM upregulate DnDNMT3 and DnTET in response to wheat expressing antibiosis and antixenosis.
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Affiliation(s)
| | | | | | | | | | - Anna-Maria Botha
- Department of Genetics, Stellenbosch University, Stellenbosch, South Africa
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11
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Claudio-Piedras F, Recio-Tótoro B, Condé R, Hernández-Tablas JM, Hurtado-Sil G, Lanz-Mendoza H. DNA Methylation in Anopheles albimanus Modulates the Midgut Immune Response Against Plasmodium berghei. Front Immunol 2020; 10:3025. [PMID: 31993053 PMCID: PMC6970940 DOI: 10.3389/fimmu.2019.03025] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 12/10/2019] [Indexed: 12/11/2022] Open
Abstract
Epigenetic mechanisms such as DNA methylation and histone post-translational modifications are fundamental for the phenotypic plasticity of insects during their interaction with the environment. In response to environmental cues, the methylation pattern in DNA is dynamically remodeled to achieve an epigenetic control of gene expression. DNA methylation is the focus of study in insects for its evolutionarily conserved character; however, there is scant knowledge about the epigenetic regulation in vector mosquitoes, especially during their infection by parasites. The aim of the present study was to evaluate the participation of DNA methylation in the immune response of Anopheles albimanus to a Plasmodium infection. For this, we first investigated the presence of a fully functional DNA methylation system in A. albimanus by assessing its potential role in larval development. Subsequently, we evaluated the transcriptional response to Plasmodium berghei of two mosquito phenotypes with different degrees of susceptibility to the parasite, in a scenario where their global DNA methylation had been pharmacologically inhibited. Our study revealed that A. albimanus has a functional DNA methylation system that is essential to larval viability, and that is also responsive to feeding and parasite challenges. The pharmacological erasure of the methylome with azacytidine or decitabine abolished the divergent responses of both mosquito phenotypes, leading to a transcriptionally similar response upon parasite challenge. This response was more specific, and the infection load in both phenotypes was lowered. Our findings suggest that DNA methylation may constitute a key factor in vector competence, and a promising target for preventing malaria transmission.
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Affiliation(s)
| | | | | | | | | | - Humberto Lanz-Mendoza
- Centro de Investigaciones Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Mexico
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12
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Abstract
Asthma is a complex trait, often associated with atopy. The genetic contribution has been evidenced by familial occurrence. Genome-wide association studies allowed for associating numerous genes with asthma, as well as identifying new loci that have a minor contribution to its phenotype. Considering the role of environmental exposure on asthma development, an increasing amount of literature has been published on epigenetic modifications associated with this pathology and especially on DNA methylation, in an attempt to better understand its missing heritability. These studies have been conducted in different tissues, but mainly in blood or its peripheral mononuclear cells. However, there is growing evidence that epigenetic changes that occur in one cell type cannot be directly translated into another one. In this review, we compare alterations in DNA methylation from different cells of the immune system and of the respiratory tract. The cell types in which data are obtained influences the global status of alteration of DNA methylation in asthmatic individuals compared to control (an increased or a decreased DNA methylation). Given that several genes were cell-type-specific, there is a great need for comparative studies on DNA methylation from different cells, but from the same individuals in order to better understand the role of epigenetics in asthma pathophysiology.
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Affiliation(s)
- Andrée-Anne Hudon Thibeault
- Département des sciences fondamentales, Université du Québec à Chicoutimi (UQAC), Saguenay, G7H 2B1 QC, Canada;
- Centre intersectoriel en santé durable (CISD), Université du Québec à Chicoutimi (UQAC), Saguenay, G7H 2B1 QC, Canada
- Quebec Respiratory Health Network, Quebec, G1V 4G5 QC, Canada
| | - Catherine Laprise
- Département des sciences fondamentales, Université du Québec à Chicoutimi (UQAC), Saguenay, G7H 2B1 QC, Canada;
- Centre intersectoriel en santé durable (CISD), Université du Québec à Chicoutimi (UQAC), Saguenay, G7H 2B1 QC, Canada
- Quebec Respiratory Health Network, Quebec, G1V 4G5 QC, Canada
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13
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Xue S, Xu H, Sun Z, Shen H, Chen S, Ouyang J, Zhou Q, Hu X, Cui H. Depletion of TRDMT1 affects 5-methylcytosine modification of mRNA and inhibits HEK293 cell proliferation and migration. Biochem Biophys Res Commun 2019; 520:60-66. [PMID: 31570165 DOI: 10.1016/j.bbrc.2019.09.098] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 09/22/2019] [Indexed: 12/29/2022]
Abstract
Human TRDMT1 is a transfer RNA (tRNA) methyltransferase for cytosine-5 methylation and has been suggested to be involved in the regulation of numerous developmental processes. However, little is known about the molecular mechanisms or their biological significance. In this study, we investigated the effects of CRISPR-based TRDMT1 knockdown on phenotypes, mRNA m5C modifications and gene expression changes in HEK293 cells. We found that knockdown of TRDMT1 significantly inhibited cell proliferation and migration but had no effect on clonogenic potential. The inhibitory effects could be attenuated by re-expression of TRDMT1 in HEK293 cells. RNA sequencing (RNA-Seq) and RNA bisulfite sequencing (RNA-BisSeq) were performed in TRDMT1 knockdown and wild-type HEK293 cells. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses indicated that the differentially expressed genes were associated with the cell cycle, RNA transport, and RNA degradation and were enriched in cancer and Notch signaling pathways. We also found that TRDMT1 knockdown could change mRNA methylation levels. For the first time, these findings clarify the role of TRDMT1 in regulating mRNA methylation and inhibiting the proliferation and migration of HEK293 cells. These results provide new insights into a new function of TRDMT1 and elucidate the molecular mechanisms of aberrant RNA m5C during tumorigenesis.
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Affiliation(s)
- Songlei Xue
- Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agricultural & Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Hui Xu
- Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, China
| | - Zhen Sun
- Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, China
| | - Hui Shen
- Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, China
| | - Shihao Chen
- Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, China
| | - Juan Ouyang
- Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, China
| | - Qiqi Zhou
- Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, China
| | - Xuming Hu
- Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agricultural & Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Hengmi Cui
- Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China; Institute of Comparative Medicine, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agricultural & Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China.
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14
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Guo X, Xie Q, Li B, Su H. Molecular characterization and transcription analysis of DNA methyltransferase genes in tomato (Solanum lycopersicum). Genet Mol Biol 2019; 43:e20180295. [PMID: 31429858 PMCID: PMC7197986 DOI: 10.1590/1678-4685-gmb-2018-0295] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 03/08/2019] [Indexed: 11/22/2022] Open
Abstract
DNA methylation plays an important role in plant growth and development, gene expression regulation, and maintenance of genome stability. However, only little information regarding stress-related DNA methyltransferases (MTases) genes is available in tomato. Here, we report the analysis of nine tomato MTases, which were categorized into four known subfamilies. Structural analysis suggested their DNA methylase domains are highly conserved, whereas the N-terminals are divergent. Tissue-specific analysis of these MTase genes revealed that SlCMT2, SlCMT3, and SlDRM5 were expressed higher in young leaves, while SlMET1, SlCMT4, SlDRM7, and SlDRM8 were highly expressed in immature green fruit, and their expression declined continuously with further fruit development. In contrast, SlMETL was highly expressed in ripening fruit and displayed an up-regulated tendency during fruit development. In addition, the expression of SlMET1 in the ripening of mutant rin and Nr tomatoes is significantly higher compared to wild-type tomato, suggesting that SlMET1 was negatively regulated by the ethylene signal and ripening regulator MADS-RIN. Furthermore, expression analysis under abiotic stresses revealed that these MTase genes were stress-responsive and may function diversely in different stress conditions. Overall, our results provide valuable information for exploring the regulation of tomato fruit ripening and response to abiotic stress through DNA methylation.
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Affiliation(s)
- Xuhu Guo
- Shanxi Datong University, School of Life Sciences, Datong, China.,Shanxi Datong University, Applied Biotechnology Institute, Datong, China
| | - Qian Xie
- Shanxi Datong University, School of Life Sciences, Datong, China.,Shanxi Datong University, Applied Biotechnology Institute, Datong, China
| | - Baoyuan Li
- Shanxi Datong University, School of Life Sciences, Datong, China.,Shanxi Datong University, Applied Biotechnology Institute, Datong, China
| | - Huanzhen Su
- Shanxi Datong University, School of Life Sciences, Datong, China
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15
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Alvarez-Ponce D, Torres-Sánchez M, Feyertag F, Kulkarni A, Nappi T. Molecular evolution of DNMT1 in vertebrates: Duplications in marsupials followed by positive selection. PLoS One 2018; 13:e0195162. [PMID: 29621315 PMCID: PMC5886458 DOI: 10.1371/journal.pone.0195162] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 03/16/2018] [Indexed: 01/01/2023] Open
Abstract
DNA methylation is mediated by a conserved family of DNA methyltransferases (Dnmts). The human genome encodes three active Dnmts (Dnmt1, Dnmt3a and Dnmt3b), the tRNA methyltransferase Dnmt2, and the regulatory protein Dnmt3L. Despite their high degree of conservation among different species, genes encoding Dnmts have been duplicated and/or lost in multiple lineages throughout evolution, indicating that the DNA methylation machinery has some potential to undergo evolutionary change. However, little is known about the extent to which this machinery, or the methylome, varies among vertebrates. Here, we study the molecular evolution of Dnmt1, the enzyme responsible for maintenance of DNA methylation patterns after replication, in 79 vertebrate species. Our analyses show that all studied species exhibit a single copy of the DNMT1 gene, with the exception of tilapia and marsupials (tammar wallaby, koala, Tasmanian devil and opossum), each of which displays two apparently functional DNMT1 copies. Our phylogenetic analyses indicate that DNMT1 duplicated before the radiation of major marsupial groups (i.e., at least ~75 million years ago), thus giving rise to two DNMT1 copies in marsupials (copy 1 and copy 2). In the opossum lineage, copy 2 was lost, and copy 1 recently duplicated again, generating three DNMT1 copies: two putatively functional genes (copy 1a and 1b) and one pseudogene (copy 1ψ). Both marsupial copies (DNMT1 copies 1 and 2) are under purifying selection, and copy 2 exhibits elevated rates of evolution and signatures of positive selection, suggesting a scenario of neofunctionalization. This gene duplication might have resulted in modifications in marsupial methylomes and their dynamics.
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Affiliation(s)
- David Alvarez-Ponce
- Department of Biology, University of Nevada, Reno, Nevada, United States of America
- * E-mail:
| | - María Torres-Sánchez
- Department of Biology, University of Nevada, Reno, Nevada, United States of America
- Department of Biodiversity, Ecology and Evolution, Complutense University of Madrid, Madrid, Spain
| | - Felix Feyertag
- Department of Biology, University of Nevada, Reno, Nevada, United States of America
| | - Asmita Kulkarni
- Department of Biology, University of Nevada, Reno, Nevada, United States of America
| | - Taylen Nappi
- Department of Biology, University of Nevada, Reno, Nevada, United States of America
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16
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Abstract
The DNA methyltransferase (DNMT) family comprises a conserved set of DNA-modifying enzymes that have a central role in epigenetic gene regulation. Recent studies have shown that the functions of the canonical DNMT enzymes - DNMT1, DNMT3A and DNMT3B - go beyond their traditional roles of establishing and maintaining DNA methylation patterns. This Review analyses how molecular interactions and changes in gene copy numbers modulate the activity of DNMTs in diverse gene regulatory functions, including transcriptional silencing, transcriptional activation and post-transcriptional regulation by DNMT2-dependent tRNA methylation. This mechanistic diversity enables the DNMT family to function as a versatile toolkit for epigenetic regulation.
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Affiliation(s)
- Frank Lyko
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
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17
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Vieira GC, Vieira GF, Sinigaglia M, da Silva Valente VL. Linking epigenetic function to electrostatics: The DNMT2 structural model example. PLoS One 2017; 12:e0178643. [PMID: 28575027 PMCID: PMC5456315 DOI: 10.1371/journal.pone.0178643] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 05/16/2017] [Indexed: 11/25/2022] Open
Abstract
The amino acid sequence of DNMT2 is very similar to the catalytic domains of bacterial and eukaryotic proteins. However, there is great variability in the region of recognition of the target sequence. While bacterial DNMT2 acts as a DNA methyltransferase, previous studies have indicated low DNA methylation activity in eukaryotic DNMT2, with preference by tRNA methylation. Drosophilids are known as DNMT2-only species and the DNA methylation phenomenon is a not elucidated case yet, as well as the ontogenetic and physiologic importance of DNMT2 for this species group. In addition, more recently study showed that methylation in the genome in Drosophila melanogaster is independent in relation to DNMT2. Despite these findings, Drosophilidae family has more than 4,200 species with great ecological diversity and historical evolution, thus we, therefore, aimed to examine the drosophilids DNMT2 in order to verify its conservation at the physicochemical and structural levels in a functional context. We examined the twenty-six DNMT2 models generated by molecular modelling and five crystallographic structures deposited in the Protein Data Bank (PDB) using different approaches. Our results showed that despite sequence and structural similarity between species close related, we found outstanding differences when they are analyzed in the context of surface distribution of electrostatic properties. The differences found in the electrostatic potentials may be linked with different affinities and processivity of DNMT2 for its different substrates (DNA, RNA or tRNA) and even for interactions with other proteins involved in the epigenetic mechanisms.
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Affiliation(s)
- Gilberto Cavalheiro Vieira
- Programa de Pós Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
- Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
- * E-mail:
| | - Gustavo Fioravanti Vieira
- Programa de Pós Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
- Núcleo de Bioinformática do Laboratório de Imunogenética, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Marialva Sinigaglia
- Programa de Pós Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
- Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
- Instituto do Câncer Infantil, Porto Alegre, RS, Brazil
| | - Vera Lúcia da Silva Valente
- Programa de Pós Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
- Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
- Programa de Pós Graduação em Biologia Animal, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
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18
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Wei H, Jiang S, Chen L, He C, Wu S, Peng H. Characterization of Cytosine Methylation and the DNA Methyltransferases of Toxoplasma gondii. Int J Biol Sci 2017; 13:458-470. [PMID: 28529454 PMCID: PMC5436566 DOI: 10.7150/ijbs.18644] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 01/22/2017] [Indexed: 01/02/2023] Open
Abstract
DNA methylation is a key epigenetic modification which confers phenotypic plasticity and adaptation. Cyst-forming strains of Toxoplasma gondii undergo tachyzoite to bradyzoite conversion after initial acute infection of a host, and the reverse conversion may occur in immune-suppressed hosts. The formation of m5C is catalyzed by DNA methyltransferase (DNMT). We identified two functional DNA methyltransferases, TgDNMTa and TgDNMTb, in T. gondii that may mediate DNA methylation. The recombinant proteins showed intrinsic methyltransferase activity; both have higher transcription levels in bradyzoites than that in tachyzoites. We performed genome-wide analysis of DNA methylation in tachyzoites and bradyzoites. The results showed more methylation sites in bradyzoites than that in tachyzoites. The most significantly enriched GO-terms of genes with DNA methylation were associated with basal cellular processes such as energy metabolism and parasite resistance to host immunity. Tachyzoite proliferation in parasitophorous vacuoles (PV) can be inhibited by the DNA methyltransferase inhibitor 5-azacytidine, a chemical analogue of the nucleotide cytosine that can inactivate DNA methyltransferases. These findings provide the first confirmation of DNA methylation in T. gondii.
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Affiliation(s)
- Haixia Wei
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, and Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, 510515, P.R. China
| | - Shichen Jiang
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, and Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, 510515, P.R. China
| | - Longfei Chen
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, and Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, 510515, P.R. China
| | - Cheng He
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, and Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, 510515, P.R. China
| | - Shuizhen Wu
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, and Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, 510515, P.R. China
| | - Hongjuan Peng
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, and Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, 510515, P.R. China
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19
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Ehrenhofer-Murray AE. Cross-Talk between Dnmt2-Dependent tRNA Methylation and Queuosine Modification. Biomolecules 2017; 7:E14. [PMID: 28208632 DOI: 10.3390/biom7010014] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 02/02/2017] [Accepted: 02/02/2017] [Indexed: 12/22/2022] Open
Abstract
Enzymes of the Dnmt2 family of methyltransferases have yielded a number of unexpected discoveries. The first surprise came more than ten years ago when it was realized that, rather than being DNA methyltransferases, Dnmt2 enzymes actually are transfer RNA (tRNA) methyltransferases for cytosine-5 methylation, foremost C38 (m5C38) of tRNAAsp. The second unanticipated finding was our recent discovery of a nutritional regulation of Dnmt2 in the fission yeast Schizosaccharomyces pombe. Significantly, the presence of the nucleotide queuosine in tRNAAsp strongly stimulates Dnmt2 activity both in vivo and in vitro in S. pombe. Queuine, the respective base, is a hypermodified guanine analog that is synthesized from guanosine-5’-triphosphate (GTP) by bacteria. Interestingly, most eukaryotes have queuosine in their tRNA. However, they cannot synthesize it themselves, but rather salvage it from food or from gut microbes. The queuine obtained from these sources comes from the breakdown of tRNAs, where the queuine ultimately was synthesized by bacteria. Queuine thus has been termed a micronutrient. This review summarizes the current knowledge of Dnmt2 methylation and queuosine modification with respect to translation as well as the organismal consequences of the absence of these modifications. Models for the functional cooperation between these modifications and its wider implications are discussed.
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20
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Abstract
The amino acid sequence of Dnmt2 is very similar to the catalytic domains of bacterial and eukaryotic DNA-(cytosine 5)-methyltransferases, but it efficiently catalyzes tRNA methylation, while its DNA methyltransferase activity is the subject of controversial reports with rates varying between zero and very weak. By using composite nucleic acid molecules as substrates, we surprisingly found that DNA fragments, when presented as covalent DNA-RNA hybrids in the structural context of a tRNA, can be more efficiently methylated than the corresponding natural tRNA substrate. Furthermore, by stepwise development of tRNAAsp, we showed that this natural Dnmt2 substrate could be engineered to employ RNAs that act like guide RNAs in vitro. The 5’-half of tRNAAsp was able to efficiently guide methylation toward a single stranded tRNA fragment as would result from tRNA cleavage by tRNA specific nucleases. In a more artificial setting, a composite system of guide RNAs could ultimately be engineered to enable the enzyme to perform cytidine methylation on single stranded DNA in vitro.
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Affiliation(s)
- Steffen Kaiser
- a Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz , Mainz , Germany
| | - Tomasz P Jurkowski
- b Institute of Biochemistry, Faculty of Chemistry, University Stuttgart , Stuttgart , Germany
| | - Stefanie Kellner
- a Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz , Mainz , Germany
| | - Dirk Schneider
- a Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz , Mainz , Germany
| | - Albert Jeltsch
- b Institute of Biochemistry, Faculty of Chemistry, University Stuttgart , Stuttgart , Germany
| | - Mark Helm
- a Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz , Mainz , Germany
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21
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Dhasarathy A, Roemmich JN, Claycombe KJ. Influence of maternal obesity, diet and exercise on epigenetic regulation of adipocytes. Mol Aspects Med 2016; 54:37-49. [PMID: 27825817 DOI: 10.1016/j.mam.2016.10.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 10/25/2016] [Accepted: 10/25/2016] [Indexed: 12/11/2022]
Affiliation(s)
- Archana Dhasarathy
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
| | - James N Roemmich
- USDA-ARS-PA, Grand Forks Human Nutrition Research Center, 2420 2nd Avenue North, Grand Forks, ND 58203, USA
| | - Kate J Claycombe
- USDA-ARS-PA, Grand Forks Human Nutrition Research Center, 2420 2nd Avenue North, Grand Forks, ND 58203, USA.
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22
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Huang R, Ding Q, Xiang Y, Gu T, Li Y. Comparative Analysis of DNA Methyltransferase Gene Family in Fungi: A Focus on Basidiomycota. Front Plant Sci 2016; 7:1556. [PMID: 27818666 PMCID: PMC5073141 DOI: 10.3389/fpls.2016.01556] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 10/03/2016] [Indexed: 06/06/2023]
Abstract
DNA methylation plays a crucial role in the regulation of gene expression in eukaryotes. Mushrooms belonging to the phylum Basidiomycota are highly valued for both nutritional and pharmaceutical uses. A growing number of studies have demonstrated the significance of DNA methylation in the development of plants and animals. However, our understanding of DNA methylation in mushrooms is limited. In this study, we identified and conducted comprehensive analyses on DNA methyltransferases (DNMtases) in representative species from Basidiomycota and Ascomycota, and obtained new insights into their classification and characterization in fungi. Our results revealed that DNMtases in basidiomycetes can be divided into two classes, the Dnmt1 class and the newly defined Rad8 class. We also demonstrated that the fusion event between the characteristic domains of the DNMtases family and Snf2 family in the Rad8 class is fungi-specific, possibly indicating a functional novelty of Rad8 DNMtases in fungi. Additionally, expression profiles of DNMtases in the edible mushroom Pleurotus ostreatus revealed diverse expression patterns in various organs and developmental stages. For example, DNMtase genes displayed higher expression levels in dikaryons than in monokaryons. Consistent with the expression profiles, we found that dikaryons are more susceptible to the DNA methyltransferase inhibitor 5-azacytidine. Taken together, our findings pinpoint an important role of DNA methylation during the growth of mushrooms and provide a foundation for understanding of DNMtases in basidiomycetes.
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Affiliation(s)
- Ruirui Huang
- State Key Laboratory of Plant Genetics and Germplasm Enhancement and College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Qiangqiang Ding
- State Key Laboratory of Plant Genetics and Germplasm Enhancement and College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Yanan Xiang
- Laboratory of Plant Hormone, College of Life Sciences, Nanjing Agricultural UniversityNanjing, China
| | - Tingting Gu
- State Key Laboratory of Plant Genetics and Germplasm Enhancement and College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Yi Li
- State Key Laboratory of Plant Genetics and Germplasm Enhancement and College of Horticulture, Nanjing Agricultural UniversityNanjing, China
- Department of Plant Science and Landscape Architecture, University of ConnecticutStorrs, CT, USA
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23
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Abstract
RNA, the earliest genetic and catalytic molecule, has a relatively delicate and labile chemical structure, when compared to DNA. It is prone to be damaged by alkali, heat, nucleases, or stress conditions. One mechanism to protect RNA or DNA from damage is through site-specific methylation. Here, we propose that RNA methylation began prior to DNA methylation in the early forms of life evolving on Earth. In this article, the biochemical properties of some RNA methyltransferases (MTases), such as 2′-O-MTases (Rlml/RlmN), spOUT MTases and the NSun2 MTases are dissected for the insight they provide on the transition from an RNA world to our present RNA/DNA/protein world.
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Affiliation(s)
- Ajay K Rana
- Division of Biology, State Forensic Science Laboratory, Ministry of Home Affairs, Government of Jharkhand Ranchi, India
| | - Serge Ankri
- Department of Molecular Microbiology, The Ruth and Bruce Rappaport Faculty of Medicine, Technion Israel Institute of Technology Haifa, Israel
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24
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Jeltsch A, Ehrenhofer-Murray A, Jurkowski TP, Lyko F, Reuter G, Ankri S, Nellen W, Schaefer M, Helm M. Mechanism and biological role of Dnmt2 in Nucleic Acid Methylation. RNA Biol 2016; 14:1108-1123. [PMID: 27232191 PMCID: PMC5699548 DOI: 10.1080/15476286.2016.1191737] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
A group of homologous nucleic acid modification enzymes called Dnmt2, Trdmt1, Pmt1, DnmA, and Ehmet in different model organisms catalyze the transfer of a methyl group from the cofactor S-adenosyl-methionine (SAM) to the carbon-5 of cytosine residues. Originally considered as DNA MTases, these enzymes were shown to be tRNA methyltransferases about a decade ago. Between the presumed involvement in DNA modification-related epigenetics, and the recent foray into the RNA modification field, significant progress has characterized Dnmt2-related research. Here, we review this progress in its diverse facets including molecular evolution, structural biology, biochemistry, chemical biology, cell biology and epigenetics.
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Affiliation(s)
- Albert Jeltsch
- a Institute of Biochemistry , Stuttgart University , Stuttgart , Germany
| | | | - Tomasz P Jurkowski
- a Institute of Biochemistry , Stuttgart University , Stuttgart , Germany
| | - Frank Lyko
- c Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center , Heidelberg , Germany
| | - Gunter Reuter
- d Institute of Biology, Developmental Genetics, Martin Luther University Halle , Halle , Germany
| | - Serge Ankri
- e Department of Molecular Microbiology , The Bruce Rappaport Faculty of Medicine , Technion , Haifa , Israel
| | - Wolfgang Nellen
- f Abteilung für Genetik, Universität Kassel , Kassel , Germany
| | - Matthias Schaefer
- g Medical University of Vienna, Center for Anatomy & Cell Biology , Vienna , Austria
| | - Mark Helm
- h Institut für Pharmazie und Biochemie, Johannes Gutenberg-Universität Mainz , Mainz , Germany
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25
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Delatte B, Wang F, Ngoc LV, Collignon E, Bonvin E, Deplus R, Calonne E, Hassabi B, Putmans P, Awe S, Wetzel C, Kreher J, Soin R, Creppe C, Limbach PA, Gueydan C, Kruys V, Brehm A, Minakhina S, Defrance M, Steward R, Fuks F. RNA biochemistry. Transcriptome-wide distribution and function of RNA hydroxymethylcytosine. Science 2016; 351:282-5. [PMID: 26816380 DOI: 10.1126/science.aac5253] [Citation(s) in RCA: 289] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Hydroxymethylcytosine, well described in DNA, occurs also in RNA. Here, we show that hydroxymethylcytosine preferentially marks polyadenylated RNAs and is deposited by Tet in Drosophila. We map the transcriptome-wide hydroxymethylation landscape, revealing hydroxymethylcytosine in the transcripts of many genes, notably in coding sequences, and identify consensus sites for hydroxymethylation. We found that RNA hydroxymethylation can favor mRNA translation. Tet and hydroxymethylated RNA are found to be most abundant in the Drosophila brain, and Tet-deficient fruitflies suffer impaired brain development, accompanied by decreased RNA hydroxymethylation. This study highlights the distribution, localization, and function of cytosine hydroxymethylation and identifies central roles for this modification in Drosophila.
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Affiliation(s)
- Benjamin Delatte
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB Cancer Research Center (U-CRC), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Fei Wang
- Waksman Institute, Department of Molecular Biology and Biochemistry, Cancer Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Long Vo Ngoc
- Laboratory of Molecular Biology of the Gene, Faculty of Sciences, Université Libre de Bruxelles, Gosselies, Belgium
| | - Evelyne Collignon
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB Cancer Research Center (U-CRC), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Elise Bonvin
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB Cancer Research Center (U-CRC), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Rachel Deplus
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB Cancer Research Center (U-CRC), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Emilie Calonne
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB Cancer Research Center (U-CRC), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Bouchra Hassabi
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB Cancer Research Center (U-CRC), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Pascale Putmans
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB Cancer Research Center (U-CRC), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Stephan Awe
- Institut für Molekularbiologie und Tumorforschung, Philipps-Universität Marburg, Marburg, Germany
| | - Collin Wetzel
- Department of Chemistry, University of Cincinnati, Cincinnati, OH, USA
| | - Judith Kreher
- Institut für Molekularbiologie und Tumorforschung, Philipps-Universität Marburg, Marburg, Germany
| | - Romuald Soin
- Laboratory of Molecular Biology of the Gene, Faculty of Sciences, Université Libre de Bruxelles, Gosselies, Belgium
| | - Catherine Creppe
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB Cancer Research Center (U-CRC), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Patrick A Limbach
- Department of Chemistry, University of Cincinnati, Cincinnati, OH, USA
| | - Cyril Gueydan
- Laboratory of Molecular Biology of the Gene, Faculty of Sciences, Université Libre de Bruxelles, Gosselies, Belgium
| | - Véronique Kruys
- Laboratory of Molecular Biology of the Gene, Faculty of Sciences, Université Libre de Bruxelles, Gosselies, Belgium
| | - Alexander Brehm
- Institut für Molekularbiologie und Tumorforschung, Philipps-Universität Marburg, Marburg, Germany
| | - Svetlana Minakhina
- Waksman Institute, Department of Molecular Biology and Biochemistry, Cancer Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Matthieu Defrance
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB Cancer Research Center (U-CRC), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Ruth Steward
- Waksman Institute, Department of Molecular Biology and Biochemistry, Cancer Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - François Fuks
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB Cancer Research Center (U-CRC), Université Libre de Bruxelles (ULB), Brussels, Belgium.
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Wijenayake S, Storey KB. The role of DNA methylation during anoxia tolerance in a freshwater turtle (Trachemys scripta elegans). J Comp Physiol B 2016; 186:333-42. [PMID: 26843075 DOI: 10.1007/s00360-016-0960-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 01/05/2016] [Accepted: 01/15/2016] [Indexed: 11/24/2022]
Abstract
Oxygen deprivation is a lethal stress that only a few animals can tolerate for extended periods. This study focuses on analyzing the role of DNA methylation in aiding natural anoxia tolerance in a champion vertebrate anaerobe, the red-eared slider turtle (Trachemys scripta elegans). We examined the relative expression and total enzymatic activity of four DNA methyltransferases (DNMT1, DNMT2, DNMT3a and DNMT3b), two methyl-binding domain proteins (MBD1 and MBD2), and relative genomic levels of 5-methylcytosine under control, 5 h anoxic, and 20 h anoxic conditions in liver, heart, and white skeletal muscle (n = 4, p < 0.05). In liver, protein expression of DNMT1, DNMT2, MBD1, and MBD2 rose significantly by two- to fourfold after 5 h anoxic submergence compared to normoxic-control conditions. In heart, 5 h anoxia submergence resulted in a 1.4-fold increase in DNMT3a levels and a significant decrease in MBD1 and MBD2 levels to ~30 % of control values. In white muscle, DNMT3a and DNMT3b increased threefold and MBD1 levels increased by 50 % in response to 5 h anoxia. Total DNMT activity rose by 0.6-2.0-fold in liver and white muscle and likewise global 5mC levels significantly increased in liver and white muscle under 5 and 20 h anoxia. The results demonstrate an overall increase in DNA methylation, DNMT protein expression and enzymatic activity in response to 5 and 20 h anoxia in liver and white muscle indicating a potential downregulation of gene expression via this epigenetic mechanism during oxygen deprivation.
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Affiliation(s)
- Sanoji Wijenayake
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Kenneth B Storey
- Department of Biology, Department of Chemistry, Canada Research Chair in Molecular Physiology, Institute of Biochemistry, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada.
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27
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Abstract
tRNA molecules undergo extensive post-transcriptional processing to generate the mature functional tRNA species that are essential for translation in all organisms. These processing steps include the introduction of numerous specific chemical modifications to nucleotide bases and sugars; among these modifications, methylation reactions are by far the most abundant. The tRNA methyltransferases comprise a diverse enzyme superfamily, including members of multiple structural classes that appear to have arisen independently during evolution. Even among closely related family members, examples of unusual substrate specificity and chemistry have been observed. Here we review recent advances in tRNA methyltransferase mechanism and function with a particular emphasis on discoveries of alternative substrate specificities and chemistry associated with some methyltransferases. Although the molecular function for a specific tRNA methylation may not always be clear, mutations in tRNA methyltransferases have been increasingly associated with human disease. The impact of tRNA methylation on human biology is also discussed.
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Affiliation(s)
- William E Swinehart
- a Center for RNA Biology and Department of Chemistry and Biochemistry ; Ohio State University ; Columbus , OH USA
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28
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Kim BM, Mirbahai L, Mally A, Kevin Chipman J, Rhee JS, Lee JS. Correlation between the DNA methyltransferase (Dnmt) gene family and genome-wide 5-methylcytosine (5mC) in rotifer, copepod, and fish. Genes Genomics 2015. [DOI: 10.1007/s13258-015-0333-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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29
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Shanmugam R, Fierer J, Kaiser S, Helm M, Jurkowski TP, Jeltsch A. Cytosine methylation of tRNA-Asp by DNMT2 has a role in translation of proteins containing poly-Asp sequences. Cell Discov 2015; 1:15010. [PMID: 27462411 PMCID: PMC4860778 DOI: 10.1038/celldisc.2015.10] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 03/26/2015] [Indexed: 01/09/2023] Open
Abstract
The Dnmt2 RNA methyltransferase catalyses the methylation of C38 in the anticodon loop of tRNA-Asp, but the molecular role of this methylation is unknown. Here, we report that mouse aspartyl-tRNA synthetase shows a four to fivefold preference for C38-methylated tRNA-Asp. Consistently, a 30% reduced charging level of tRNA-Asp was observed in Dnmt2 knockout (KO) murine embryonic fibroblast cells. Gene expression analysis with fluorescent reporter proteins fused to an N-terminal poly-Asp sequence showed that protein synthesis of poly-Asp-tagged reporter proteins was reduced in Dnmt2 KO cells as well. The same effect was observed with endogenous proteins containing poly-Asp sequences, indicating that Dnmt2-mediated C38 methylation of tRNA-Asp regulates the translation of proteins containing poly-Asp sequences. Gene ontology searches for proteins containing poly-Asp sequences in the human proteome showed that a significant number of these proteins have roles in transcriptional regulation and gene expression. Hence, the Dnmt2-mediated methylation of tRNA-Asp exhibits a post-transcriptional regulatory role by controlling the synthesis of a group of target proteins containing poly-Asp sequences.
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Affiliation(s)
- Raghuvaran Shanmugam
- Institute of Biochemistry, Stuttgart University, Faculty of Chemistry , Stuttgart, Germany
| | - Jacob Fierer
- MoLife Program, School of Engineering and Science, Jacobs University Bremen , Bremen, Germany
| | - Steffen Kaiser
- Institute of Pharmacy and Biochemistry, Faculty of Chemistry, Pharmaceutical Sciences and Geoscience, Johannes Gutenberg-Universität Mainz , Mainz, Germany
| | - Mark Helm
- Institute of Pharmacy and Biochemistry, Faculty of Chemistry, Pharmaceutical Sciences and Geoscience, Johannes Gutenberg-Universität Mainz , Mainz, Germany
| | - Tomasz P Jurkowski
- Institute of Biochemistry, Stuttgart University, Faculty of Chemistry , Stuttgart, Germany
| | - Albert Jeltsch
- Institute of Biochemistry, Stuttgart University, Faculty of Chemistry , Stuttgart, Germany
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30
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Kim SH, Cho HJ, Sohn WM, Ahn CS, Kong Y, Yang HJ, Bae YA. Egg-specific expression of protein with DNA methyltransferase activity in the biocarcinogenic liver fluke Clonorchis sinensis. Parasitology 2015; 142:1228-38. [PMID: 26036304 DOI: 10.1017/S0031182015000566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Despite recent reports regarding the biology of cytosine methylation in Schistosoma mansoni, the impact of the regulatory machinery remains unclear in diverse platyhelminthes. This ambiguity is reinforced by discoveries of DNA methyltransferase 2 (DNMT2)-only organisms and the substrate specificity of DNMT2 preferential to RNA molecules. Here, we characterized a novel DNA methyltransferase, named CsDNMT2, in a liver fluke Clonorchis sinensis. The protein exhibited structural properties conserved in other members of the DNMT2 family. The native and recombinant CsDNMT2 exhibited considerable enzymatic activity on DNA. The spatiotemporal expression of CsDNMT2 mirrored that of 5-methylcytosine (5 mC), both of which were elevated in the C. sinensis eggs. However, CsDNMT2 and 5 mC were marginally detected in other histological regions of C. sinensis adults including ovaries and seminal receptacle. The methylation site seemed not related to genomic loci occupied by progenies of an active long-terminal-repeat retrotransposon. Taken together, our data strongly suggest that C. sinensis has preserved the functional DNA methylation machinery and that DNMT2 acts as a genuine alternative to DNMT1/DNMT3 to methylate DNA in the DNMT2-only organism. The epigenetic regulation would target functional genes primarily involved in the formation and/or maturation of eggs, rather than retrotransposons.
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31
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Illi B, Ciarapica R, Capogrossi MC. Chromatin methylation and cardiovascular aging. J Mol Cell Cardiol 2015; 83:21-31. [DOI: 10.1016/j.yjmcc.2015.02.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 01/20/2015] [Accepted: 02/12/2015] [Indexed: 12/26/2022]
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32
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Elhardt W, Shanmugam R, Jurkowski TP, Jeltsch A. Somatic cancer mutations in the DNMT2 tRNA methyltransferase alter its catalytic properties. Biochimie 2015; 112:66-72. [PMID: 25747896 DOI: 10.1016/j.biochi.2015.02.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 02/24/2015] [Indexed: 12/22/2022]
Abstract
Methylation of tRNA is an important post-transcriptional modification and aberrations in tRNA modification has been implicated in cancer. The DNMT2 protein methylates C38 of tRNA-Asp and it has a role in cellular physiology and stress response and its expression levels are altered in cancer tissues. Here we studied whether DNMT2 somatic mutations found in cancer tissues affect the activity of the enzyme. We have generated 13 DNMT2 variants and purified the corresponding proteins. All proteins were properly folded as determined by circular dichroism spectroscopy. We tested their RNA methylation activity using in vitro generated tRNA-Asp. One of the mutations (E63K) caused a twofold increase in activity, while two of them led to a strong (over fourfold) decrease in activity (G155S and L257V). Two additional mutant proteins were almost inactive (R371H and G155V). The strong effect of some of the somatic cancer mutations on DNMT2 activity suggests that these mutations have a functional role in tumorigenesis.
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Affiliation(s)
- Winfried Elhardt
- Institute of Biochemistry, Stuttgart University, 70569 Stuttgart, Germany
| | | | - Tomasz P Jurkowski
- Institute of Biochemistry, Stuttgart University, 70569 Stuttgart, Germany.
| | - Albert Jeltsch
- Institute of Biochemistry, Stuttgart University, 70569 Stuttgart, Germany.
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33
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Shanmugam R, Aklujkar M, Schäfer M, Reinhardt R, Nickel O, Reuter G, Lovley DR, Ehrenhofer-Murray A, Nellen W, Ankri S, Helm M, Jurkowski TP, Jeltsch A. The Dnmt2 RNA methyltransferase homolog of Geobacter sulfurreducens specifically methylates tRNA-Glu. Nucleic Acids Res 2014; 42:6487-96. [PMID: 24711368 PMCID: PMC4041430 DOI: 10.1093/nar/gku256] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Dnmt2 enzymes are conserved in eukaryotes, where they methylate C38 of tRNA-Asp with high activity. Here, the activity of one of the very few prokaryotic Dnmt2 homologs from Geobacter species (GsDnmt2) was investigated. GsDnmt2 was observed to methylate tRNA-Asp from flies and mice. Unexpectedly, it had only a weak activity toward its matching Geobacter tRNA-Asp, but methylated Geobacter tRNA-Glu with good activity. In agreement with this result, we show that tRNA-Glu is methylated in Geobacter while the methylation is absent in tRNA-Asp. The activities of Dnmt2 enzymes from Homo sapiens, Drosophila melanogaster, Schizosaccharomyces pombe and Dictyostelium discoideum for methylation of the Geobacter tRNA-Asp and tRNA-Glu were determined showing that all these Dnmt2s preferentially methylate tRNA-Asp. Hence, the GsDnmt2 enzyme has a swapped transfer ribonucleic acid (tRNA) specificity. By comparing the different tRNAs, a characteristic sequence pattern was identified in the variable loop of all preferred tRNA substrates. An exchange of two nucleotides in the variable loop of murine tRNA-Asp converted it to the corresponding variable loop of tRNA-Glu and led to a strong reduction of GsDnmt2 activity. Interestingly, the same loss of activity was observed with human DNMT2, indicating that the variable loop functions as a specificity determinant in tRNA recognition of Dnmt2 enzymes.
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Affiliation(s)
| | - Muktak Aklujkar
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003-9298, USA
| | - Matthias Schäfer
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, 69120 Heidelberg, Germany
| | | | - Olaf Nickel
- Institute of Biology, Developmental Genetics, Martin Luther University Halle, 06120 Halle, Germany
| | - Gunter Reuter
- Institute of Biology, Developmental Genetics, Martin Luther University Halle, 06120 Halle, Germany
| | - Derek R Lovley
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003-9298, USA
| | | | - Wolfgang Nellen
- Department of Genetics, University of Kassel, 34132 Kassel, Germany
| | - Serge Ankri
- Department of Molecular Microbiology, The Bruce Rappaport Faculty of Medicine, Technion, Haifa 31096, Israel
| | - Mark Helm
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Tomasz P Jurkowski
- Institute of Biochemistry, Stuttgart University, 70569 Stuttgart, Germany
| | - Albert Jeltsch
- Institute of Biochemistry, Stuttgart University, 70569 Stuttgart, Germany
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34
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Dunwell TL, McGuffin LJ, Dunwell JM, Pfeifer GP. The mysterious presence of a 5-methylcytosine oxidase in the Drosophila genome: possible explanations. Cell Cycle 2013; 12:3357-65. [PMID: 24091536 DOI: 10.4161/cc.26540] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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35
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Müller S, Windhof IM, Maximov V, Jurkowski T, Jeltsch A, Förstner KU, Sharma CM, Gräf R, Nellen W. Target recognition, RNA methylation activity and transcriptional regulation of the Dictyostelium discoideum Dnmt2-homologue (DnmA). Nucleic Acids Res 2013; 41:8615-27. [PMID: 23877245 PMCID: PMC3794594 DOI: 10.1093/nar/gkt634] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Although the DNA methyltransferase 2 family is highly conserved during evolution and recent reports suggested a dual specificity with stronger activity on transfer RNA (tRNA) than DNA substrates, the biological function is still obscure. We show that the Dictyostelium discoideum Dnmt2-homologue DnmA is an active tRNA methyltransferase that modifies C38 in tRNAAsp(GUC)in vitro and in vivo. By an ultraviolet-crosslinking and immunoprecipitation approach, we identified further DnmA targets. This revealed specific tRNA fragments bound by the enzyme and identified tRNAGlu(CUC/UUC) and tRNAGly(GCC) as new but weaker substrates for both human Dnmt2 and DnmA in vitro but apparently not in vivo. Dnmt2 enzymes form transient covalent complexes with their substrates. The dynamics of complex formation and complex resolution reflect methylation efficiency in vitro. Quantitative PCR analyses revealed alterations in dnmA expression during development, cell cycle and in response to temperature stress. However, dnmA expression only partially correlated with tRNA methylation in vivo. Strikingly, dnmA expression in the laboratory strain AX2 was significantly lower than in the NC4 parent strain. As expression levels and binding of DnmA to a target in vivo are apparently not necessarily accompanied by methylation, we propose an additional biological function of DnmA apart from methylation.
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Affiliation(s)
- Sara Müller
- Department of Genetics, University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany, Institute of Biochemistry, University Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany, Research Center for Infectious Diseases (ZINF), University of Würzburg, Josef-Schneider-Str. 2/Bau D15, 97080 Würzburg and Universität Potsdam, Institut für Biochemie und Biologie, Abt. Zellbiologie, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam - Golm
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36
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Abstract
A growing body of evidence has drawn the attention of the scientific community by indicating the potential vulnerability to environmental changes of epigenetic mechanisms that control gene expression. Being critical components of normal development, the importance of epigenetic mechanisms for normal biology is illustrated by the fact that abnormal epigenetic patterns have increasingly been linked to the aetiology of various diseases including cancer, paediatric syndromes, autoimmune diseases, genetic disorders and even the molecular process of ageing. It is estimated that the degree of vulnerability to changes in epigenetic patterns is high during early embryonic development, a period of life in which epigenetic patterns are established and cell differentiation is intense. Moreover, increasing amounts of relevant data and information reveal that the environment might potentially impact on epigenetic patterns at every period of life. Within this context, in this study we will review the principles of epigenetic vulnerability to environmental changes, the impacts on development, the association with the origin of common diseases and also speculate about the potential of lifestyle changes to modulate epigenetic patterns and contribute to preventing common diseases.
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37
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Sibbritt T, Patel HR, Preiss T. Mapping and significance of the mRNA methylome. Wiley Interdiscip Rev RNA 2013; 4:397-422. [PMID: 23681756 DOI: 10.1002/wrna.1166] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 03/20/2013] [Accepted: 03/22/2013] [Indexed: 12/25/2022]
Abstract
Internal methylation of eukaryotic mRNAs in the form of N6-methyladenosine (m(6)A) and 5-methylcytidine (m(5)C) has long been known to exist, but progress in understanding its role was hampered by difficulties in identifying individual sites. This was recently overcome by high-throughput sequencing-based methods that mapped thousands of sites for both modifications throughout mammalian transcriptomes, with most sites found in mRNAs. The topology of m(6)A in mouse and human revealed both conserved and variable sites as well as plasticity in response to extracellular cues. Within mRNAs, m(5)C and m(6)A sites were relatively depleted in coding sequences and enriched in untranslated regions, suggesting functional interactions with post-transcriptional gene control. Finer distribution analyses and preexisting literature point toward roles in the regulation of mRNA splicing, translation, or decay, through an interplay with RNA-binding proteins and microRNAs. The methyltransferase (MTase) METTL3 'writes' m(6)A marks on mRNA, whereas the demethylase FTO can 'erase' them. The RNA:m(5)C MTases NSUN2 and TRDMT1 have roles in tRNA methylation but they also act on mRNA. Proper functioning of these enzymes is important in development and there are clear links to human disease. For instance, a common variant of FTO is a risk allele for obesity carried by 1 billion people worldwide and mutations cause a lethal syndrome with growth retardation and brain deficits. NSUN2 is linked to cancer and stem cell biology and mutations cause intellectual disability. In this review, we summarize the advances, open questions, and intriguing possibilities in this emerging field that might be called RNA modomics or epitranscriptomics.
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Affiliation(s)
- Tennille Sibbritt
- Genome Biology Department, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
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38
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Raddatz G, Guzzardo PM, Olova N, Fantappié MR, Rampp M, Schaefer M, Reik W, Hannon GJ, Lyko F. Dnmt2-dependent methylomes lack defined DNA methylation patterns. Proc Natl Acad Sci U S A. 2013;110:8627-8631. [PMID: 23641003 DOI: 10.1073/pnas.1306723110] [Citation(s) in RCA: 164] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Several organisms have retained methyltransferase 2 (Dnmt2) as their only candidate DNA methyltransferase gene. However, information about Dnmt2-dependent methylation patterns has been limited to a few isolated loci and the results have been discussed controversially. In addition, recent studies have shown that Dnmt2 functions as a tRNA methyltransferase, which raised the possibility that Dnmt2-only genomes might be unmethylated. We have now used whole-genome bisulfite sequencing to analyze the methylomes of Dnmt2-only organisms at single-base resolution. Our results show that the genomes of Schistosoma mansoni and Drosophila melanogaster lack detectable DNA methylation patterns. Residual unconverted cytosine residues shared many attributes with bisulfite deamination artifacts and were observed at comparable levels in Dnmt2-deficient flies. Furthermore, genetically modified Dnmt2-only mouse embryonic stem cells lost the DNA methylation patterns found in wild-type cells. Our results thus uncover fundamental differences among animal methylomes and suggest that DNA methylation is dispensable for a considerable number of eukaryotic organisms.
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39
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Becker M, Müller S, Nellen W, Jurkowski TP, Jeltsch A, Ehrenhofer-Murray AE. Pmt1, a Dnmt2 homolog in Schizosaccharomyces pombe, mediates tRNA methylation in response to nutrient signaling. Nucleic Acids Res 2012; 40:11648-58. [PMID: 23074192 PMCID: PMC3526270 DOI: 10.1093/nar/gks956] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The fission yeast Schizosaccharomyces pombe carries a cytosine 5-methyltransferase homolog of the Dnmt2 family (termed pombe methyltransferase 1, Pmt1), but contains no detectable DNA methylation. Here, we found that Pmt1, like other Dnmt2 homologs, has in vitro methylation activity on cytosine 38 of tRNAAsp and, to a lesser extent, of tRNAGlu, despite the fact that it contains a non-consensus residue in catalytic motif IV as compared with its homologs. In vivo tRNA methylation also required Pmt1. Unexpectedly, however, its in vivo activity showed a strong dependence on the nutritional status of the cell because Pmt1-dependent tRNA methylation was induced in cells grown in the presence of peptone or with glutamate as a nitrogen source. Furthermore, this induction required the serine/threonine kinase Sck2, but not the kinases Sck1, Pka1 or Tor1 and was independent of glucose signaling. Taken together, this work reveals a novel connection between nutrient signaling and tRNA methylation that thus may link tRNA methylation to processes downstream of nutrient signaling like ribosome biogenesis and translation initiation.
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Affiliation(s)
- Maria Becker
- Zentrum für Medizinische Biotechnologie, Universität Duisburg-Essen, 45117 Essen, Germany
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40
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Malik G, Dangwal M, Kapoor S, Kapoor M. Role of DNA methylation in growth and differentiation inPhyscomitrella patensand characterization of cytosine DNA methyltransferases. FEBS J 2012; 279:4081-94. [DOI: 10.1111/febs.12002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 08/14/2012] [Accepted: 08/30/2012] [Indexed: 12/30/2022]
Affiliation(s)
- Garima Malik
- University School of Biotechnology; Guru Gobind Singh Indraprastha University; New Delhi; India
| | - Meenakshi Dangwal
- University School of Biotechnology; Guru Gobind Singh Indraprastha University; New Delhi; India
| | - Sanjay Kapoor
- Interdisciplinary Centre for Plant Genomics and Department of Plant Molecular Biology; University of Delhi South Campus; New Delhi; India
| | - Meenu Kapoor
- University School of Biotechnology; Guru Gobind Singh Indraprastha University; New Delhi; India
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41
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Rodriguez-Osorio N, Urrego R, Cibelli JB, Eilertsen K, Memili E. Reprogramming mammalian somatic cells. Theriogenology 2012; 78:1869-86. [PMID: 22979962 DOI: 10.1016/j.theriogenology.2012.05.030] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 05/20/2012] [Accepted: 05/31/2012] [Indexed: 01/23/2023]
Abstract
Somatic cell nuclear transfer (SCNT), the technique commonly known as cloning, permits transformation of a somatic cell into an undifferentiated zygote with the potential to develop into a newborn animal (i.e., a clone). In somatic cells, chromatin is programmed to repress most genes and express some, depending on the tissue. It is evident that the enucleated oocyte provides the environment in which embryonic genes in a somatic cell can be expressed. This process is controlled by a series of epigenetic modifications, generally referred to as "nuclear reprogramming," which are thought to involve the removal of reversible epigenetic changes acquired during cell differentiation. A similar process is thought to occur by overexpression of key transcription factors to generate induced pluripotent stem cells (iPSCs), bypassing the need for SCNT. Despite its obvious scientific and medical importance, and the great number of studies addressing the subject, the molecular basis of reprogramming in both reprogramming strategies is largely unknown. The present review focuses on the cellular and molecular events that occur during nuclear reprogramming in the context of SCNT and the various approaches currently being used to improve nuclear reprogramming. A better understanding of the reprogramming mechanism will have a direct impact on the efficiency of current SCNT procedures, as well as iPSC derivation.
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42
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Jurkowski TP, Shanmugam R, Helm M, Jeltsch A. Mapping the tRNA Binding Site on the Surface of Human DNMT2 Methyltransferase. Biochemistry 2012; 51:4438-44. [DOI: 10.1021/bi3002659] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Tomasz P. Jurkowski
- Biochemistry Laboratory, School
of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany, and Institute of Biochemistry,
Faculty of Chemistry, Stuttgart University, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Raghuvaran Shanmugam
- Biochemistry Laboratory, School
of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany, and Institute of Biochemistry,
Faculty of Chemistry, Stuttgart University, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Mark Helm
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg-Universität Mainz, Staudinger
Weg 5, 55128 Mainz, Germany
| | - Albert Jeltsch
- Biochemistry Laboratory, School
of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany, and Institute of Biochemistry,
Faculty of Chemistry, Stuttgart University, Pfaffenwaldring 55, 70569 Stuttgart, Germany
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Albalat R, Martí-Solans J, Cañestro C. DNA methylation in amphioxus: from ancestral functions to new roles in vertebrates. Brief Funct Genomics 2012; 11:142-55. [PMID: 22389042 DOI: 10.1093/bfgp/els009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In vertebrates, DNA methylation is an epigenetic mechanism that modulates gene transcription, and plays crucial roles during development, cell fate maintenance, germ cell pluripotency and inheritable genome imprinting. DNA methylation might also play a role as a genome defense mechanism against the mutational activity derived from transposon mobility. In contrast to the heavily methylated genomes in vertebrates, most genomes in invertebrates are poorly or just moderately methylated, and the function of DNA methylation remains unclear. Here, we review the DNA methylation system in the cephalochordate amphioxus, which belongs to the most basally divergent group of our own phylum, the chordates. First, surveys of the amphioxus genome database reveal the presence of the DNA methylation machinery, DNA methyltransferases and methyl-CpG-binding domain proteins. Second, comparative genomics and analyses of conserved synteny between amphioxus and vertebrates provide robust evidence that the DNA methylation machinery of amphioxus represents the ancestral toolkit of chordates, and that its expansion in vertebrates was originated by the two rounds of whole-genome duplication that occurred in stem vertebrates. Third, in silico analysis of CpGo/e ratios throughout the amphioxus genome suggests a bimodal distribution of DNA methylation, consistent with a mosaic pattern comprising domains of methylated DNA interspersed with domains of unmethylated DNA, similar to the situation described in ascidians, but radically different to the globally methylated vertebrate genomes. Finally, we discuss potential roles of the DNA methylation system in amphioxus in the context of chordate genome evolution and the origin of vertebrates.
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Abstract
Understanding the molecular mechanisms involved in the control of cell differentiation during embryonic development is currently one of the main objectives of developmental biology. This knowledge will provide a basis for the development of new strategies in the field of regenerative medicine, one of the most promising weapons to fight many human diseases. Cell differentiation during embryonic development is controlled primarily by epigenetic factors, that is, mechanisms involved in the regulation of chromatin structure and gene expression. Here we describe the best known epigenetic modifications, and pathways, mainly focused on DNA methylation and histone modifications, and try to depict the state of art in our knowledge about epigenetic regulation of embryonic stem cell maintenance and differentiation.
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Abstract
The Dnmt2 enzymes show strong amino acid sequence similarity with eukaryotic and prokaryotic DNA-(cytosine C5)-methyltransferases. Yet, Dnmt2 enzymes from several species were shown to methylate tRNA-Asp and had been proposed that eukaryotic DNA methyltransferases evolved from a Dnmt2-like tRNA methyltransferase ancestor [Goll et al., 2006, Science, 311, 395-8]. It was the aim of this study to investigate if this hypothesis could be supported by evidence from sequence alignments. We present phylogenetic analyses based on sequence alignments of the methyltransferase catalytic domains of more than 2300 eukaryotic and prokaryotic DNA-(cytosine C5)-methyltransferases and analyzed the distribution of DNA methyltransferases in eukaryotic species. The Dnmt2 homologues were reliably identified by an additional conserved CFT motif next to motif IX. All DNA methyltransferases and Dnmt2 enzymes were clearly separated from other RNA-(cytosine-C5)-methyltransferases. Our sequence alignments and phylogenetic analyses indicate that the last universal eukaryotic ancestor contained at least one member of the Dnmt1, Dnmt2 and Dnmt3 families of enzymes and additional RNA methyltransferases. The similarity of Dnmt2 enzymes with DNA methyltransferases and absence of similarity with RNA methyltransferases combined with their strong RNA methylation activity suggest that the ancestor of Dnmt2 was a DNA methyltransferase and an early Dnmt2 enzyme changed its substrate preference to tRNA. There is no phylogenetic evidence that Dnmt2 was the precursor of eukaryotic Dnmts. Most likely, the eukaryotic Dnmt1 and Dnmt3 families of DNA methyltransferases had an independent origin in the prokaryotic DNA methyltransferase sequence space.
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Affiliation(s)
- Tomasz P. Jurkowski
- School of Engineering and Science, Jacobs University Bremen, Campus Ring Bremen, Germany
| | - Albert Jeltsch
- School of Engineering and Science, Jacobs University Bremen, Campus Ring Bremen, Germany
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Rangel-Salazar R, Wickström-Lindholm M, Aguilar-Salinas CA, Alvarado-Caudillo Y, Døssing KBV, Esteller M, Labourier E, Lund G, Nielsen FC, Rodríguez-Ríos D, Solís-Martínez MO, Wrobel K, Wrobel K, Zaina S. Human native lipoprotein-induced de novo DNA methylation is associated with repression of inflammatory genes in THP-1 macrophages. BMC Genomics 2011; 12:582. [PMID: 22118513 PMCID: PMC3247910 DOI: 10.1186/1471-2164-12-582] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 11/25/2011] [Indexed: 01/31/2023] Open
Abstract
Background We previously showed that a VLDL- and LDL-rich mix of human native lipoproteins induces a set of repressive epigenetic marks, i.e. de novo DNA methylation, histone 4 hypoacetylation and histone 4 lysine 20 (H4K20) hypermethylation in THP-1 macrophages. Here, we: 1) ask what gene expression changes accompany these epigenetic responses; 2) test the involvement of candidate factors mediating the latter. We exploited genome expression arrays to identify target genes for lipoprotein-induced silencing, in addition to RNAi and expression studies to test the involvement of candidate mediating factors. The study was conducted in human THP-1 macrophages. Results Native lipoprotein-induced de novo DNA methylation was associated with a general repression of various critical genes for macrophage function, including pro-inflammatory genes. Lipoproteins showed differential effects on epigenetic marks, as de novo DNA methylation was induced by VLDL and to a lesser extent by LDL, but not by HDL, and VLDL induced H4K20 hypermethylation, while HDL caused H4 deacetylation. The analysis of candidate factors mediating VLDL-induced DNA hypermethylation revealed that this response was: 1) surprisingly, mediated exclusively by the canonical maintenance DNA methyltransferase DNMT1, and 2) independent of the Dicer/micro-RNA pathway. Conclusions Our work provides novel insights into epigenetic gene regulation by native lipoproteins. Furthermore, we provide an example of DNMT1 acting as a de novo DNA methyltransferase independently of canonical de novo enzymes, and show proof of principle that de novo DNA methylation can occur independently of a functional Dicer/micro-RNA pathway in mammals.
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Abstract
Dnmt1, the principal DNA methyltransferase in mammalian cells, is a large and a highly dynamic enzyme with multiple regulatory features that can control DNA methylation in cells. This chapter highlights how insights into Dnmt1 structure and function can advance our understanding of DNA methylation in cells. The allosteric site(s) on Dnmt1 can regulate processes of de novo and maintenance DNA methylation in cells. Remaining open questions include which molecules, by what mechanism, bind at the allosteric site(s) in cells? Different phosphorylation sites on Dnmt1 can change its activity or ability to bind DNA target sites. Thirty-one different molecules are currently known to have physical and/or functional interaction with Dnmt1 in cells. The Dnmt1 structure and enzymatic mechanism offer unique insights into those interactions. The interacting molecules are involved in chromatin organization, DNA repair, cell cycle regulation, and apoptosis and also include RNA polymerase II, some RNA-binding proteins, and some specific Dnmt1-inhibitory RNA molecules. Combined insights from studies of different enzymatic features of Dnmt1 offer novel ideas for development of drug candidates, and can be used in selection of promising drug candidates from more than 15 different compounds that have been identified as possible inhibitors of DNA methylation in cells.
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Affiliation(s)
- Željko M Svedružić
- Medical Biochemistry, PB Rab, Faculty of Medicine, University of Rijeka, Rab, Croatia
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Abstract
Epigenetics is the study of mitotically or meiotically heritable changes in gene function that occur without a change in the DNA sequence. Interestingly, epigenetic changes can be triggered by environmental factors. Environmental exposure to e.g. metals, persistent organic pollutants or endocrine disrupting chemicals has been shown to modulate epigenetic marks, not only in mammalian cells or rodents, but also in environmentally relevant species such as fish or water fleas. The associated changes in gene expression often lead to modifications in the affected organism's phenotype. Epigenetic changes can in some cases be transferred to subsequent generations, even when these generations are no longer exposed to the external factor which induced the epigenetic change, as observed in a study with fungicide exposed rats. The possibility of this phenomenon in other species was demonstrated in water fleas exposed to the epigenetic drug 5-azacytidine. This way, populations can experience the effects of their ancestors' exposure to chemicals, which has implications for environmental risk assessment. More basic research is needed to assess the potential phenotypic and population-level effects of epigenetic modifications in different species and to evaluate the persistence of chemical exposure-induced epigenetic effects in multiple subsequent generations.
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Affiliation(s)
- Michiel B Vandegehuchte
- Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University (UGent), Jozef Plateaustraat 22, 9000 Ghent, Belgium.
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Abstract
Drosophila belongs to the so-called "Dnmt2 only" organisms, and does not contain any of the canonical DNA methyltransferases (Dnmt1 and Dnmt3). Furthermore, no functional homologs of known 5-methylcytosine reader proteins are found. Nevertheless, there is strong evidence for DNA methylation in this organism. It has been suggested that DNA methylation in Drosophila is simply a byproduct of Dnmt2, which is a DNA methyltransferase (Dnmt) according to structure and type of catalysis but functions in vivo as a tRNA methyltransferase. However, concerning the very specific timing of cytosine methylation in Drosophila, their suggested functions in control of retrotransposon silencing and genome stability, and the obvious DNA methylation activity of Dnmt2 enzymes in the protozoans Dictyostelium discoideum and Entamoeba histolytica, we tend to disagree with this notation. Dnmt2 probably serves, and not only in Drosophila, as a methyltransferase of both specific DNA and tRNA targets.
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Affiliation(s)
- Veiko Krauss
- Developmental Genetics, Institute of Biology, Martin Luther University Halle-Wittenberg, Weinbergweg, Halle/S, Germany
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Tovy A, Hofmann B, Helm M, Ankri S. In vitro tRNA methylation assay with the Entamoeba histolytica DNA and tRNA methyltransferase Dnmt2 (Ehmeth) enzyme. J Vis Exp 2010:2390. [PMID: 21048666 DOI: 10.3791/2390] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Protozoan parasites are among the most devastating infectious agents of humans responsible for a variety of diseases including amebiasis, which is one of the three most common causes of death from parasitic disease. The agent of amebiasis is the amoeba parasite Entamoeba histolytica that exists under two stages: the infective cyst found in food or water and the invasive trophozoite living in the intestine. The clinical manifestations of amebiasis range from being asymptomatic to colitis, dysentery or liver abscesses. E. histolytica is one of the rare unicellular parasite with 5-methylcytosine (5mC) in its genome. It contains a single DNA methyltransferase, Ehmeth, that belongs to the Dnmt2 family. A role for Dnmt2 in the control of repetitive elements has been established in E. histolytica, Dictyostelium discoideum and Drosophila. Our recent work has shown that Ehmeth methylates tRNA(Asp), and this finding indicates that this enzyme has a dual DNA/tRNA(Asp) methyltransferase activity. This observation is in agreement with the dual activity that has been reported for D. discoideum and D. melanogaster. The functional significance of the DNA/tRNA specificity of Dnmt2 enzymes is still unknown. To address this question, a method to determine the tRNA methyltransferase activity of Dnmt2 proteins was established. In this video, we describe a straightforward approach to prepare an adequate tRNA substrate for Dnmt2 and a method to measure its tRNA methyltransferase activity.
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Affiliation(s)
- Ayala Tovy
- Faculty of Medicine, Rappaport Institute, Technion - Israel Institute of Technology
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