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Sheng Y, Wang Y, Yang W, Wang XQ, Lu J, Pan B, Nan B, Liu Y, Ye F, Li C, Song J, Dou Y, Gao S, Liu Y. Semiconservative transmission of DNA N 6-adenine methylation in a unicellular eukaryote. Genome Res 2024; 34:740-756. [PMID: 38744529 DOI: 10.1101/gr.277843.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 04/15/2024] [Indexed: 05/16/2024]
Abstract
Although DNA N 6-adenine methylation (6mA) is best known in prokaryotes, its presence in eukaryotes has recently generated great interest. Biochemical and genetic evidence supports that AMT1, an MT-A70 family methyltransferase (MTase), is crucial for 6mA deposition in unicellular eukaryotes. Nonetheless, the 6mA transmission mechanism remains to be elucidated. Taking advantage of single-molecule real-time circular consensus sequencing (SMRT CCS), here we provide definitive evidence for semiconservative transmission of 6mA in Tetrahymena thermophila In wild-type (WT) cells, 6mA occurs at the self-complementary ApT dinucleotide, mostly in full methylation (full-6mApT); after DNA replication, hemi-methylation (hemi-6mApT) is transiently present on the parental strand, opposite to the daughter strand readily labeled by 5-bromo-2'-deoxyuridine (BrdU). In ΔAMT1 cells, 6mA predominantly occurs as hemi-6mApT. Hemi-to-full conversion in WT cells is fast, robust, and processive, whereas de novo methylation in ΔAMT1 cells is slow and sporadic. In Tetrahymena, regularly spaced 6mA clusters coincide with the linker DNA of nucleosomes arrayed in the gene body. Importantly, in vitro methylation of human chromatin by the reconstituted AMT1 complex recapitulates preferential targeting of hemi-6mApT sites in linker DNA, supporting AMT1's intrinsic and autonomous role in maintenance methylation. We conclude that 6mA is transmitted by a semiconservative mechanism: full-6mApT is split by DNA replication into hemi-6mApT, which is restored to full-6mApT by AMT1-dependent maintenance methylation. Our study dissects AMT1-dependent maintenance methylation and AMT1-independent de novo methylation, reveals a 6mA transmission pathway with a striking similarity to 5-methylcytosine (5mC) transmission at the CpG dinucleotide, and establishes 6mA as a bona fide eukaryotic epigenetic mark.
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Affiliation(s)
- Yalan Sheng
- MOE Key Laboratory of Evolution and Marine Biodiversity and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao 266237, China
| | - Yuanyuan Wang
- MOE Key Laboratory of Evolution and Marine Biodiversity and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao 266237, China
| | - Wentao Yang
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
| | - Xue Qing Wang
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
| | - Jiuwei Lu
- Department of Biochemistry, University of California Riverside, Riverside, California 92521, USA
| | - Bo Pan
- MOE Key Laboratory of Evolution and Marine Biodiversity and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao 266237, China
| | - Bei Nan
- MOE Key Laboratory of Evolution and Marine Biodiversity and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao 266237, China
| | - Yongqiang Liu
- MOE Key Laboratory of Evolution and Marine Biodiversity and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao 266237, China
| | - Fei Ye
- MOE Key Laboratory of Evolution and Marine Biodiversity and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao 266237, China
| | - Chun Li
- Division of Biostatistics, Department of Preventive Medicine, University of Southern California, Los Angeles, California 90033, USA
| | - Jikui Song
- Department of Biochemistry, University of California Riverside, Riverside, California 92521, USA
| | - Yali Dou
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
| | - Shan Gao
- MOE Key Laboratory of Evolution and Marine Biodiversity and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China;
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao 266237, China
| | - Yifan Liu
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA;
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Zhang L, Mu Y, Li T, Hu J, Lin H, Zhang L. Molecular basis of an atypical dsDNA 5mC/6mA bifunctional dioxygenase CcTet from Coprinopsis cinerea in catalyzing dsDNA 5mC demethylation. Nucleic Acids Res 2024; 52:3886-3895. [PMID: 38324471 PMCID: PMC11040006 DOI: 10.1093/nar/gkae066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/22/2023] [Accepted: 01/24/2024] [Indexed: 02/09/2024] Open
Abstract
The eukaryotic epigenetic modifications 5-methyldeoxycytosine (5mC) and N6-methyldeoxyadenine (6mA) have indispensable regulatory roles in gene expression and embryonic development. We recently identified an atypical bifunctional dioxygenase CcTet from Coprinopsis cinerea that works on both 5mC and 6mA demethylation. The nonconserved residues Gly331 and Asp337 of CcTet facilitate 6mA accommodation, while D337F unexpectedly abolishes 5mC oxidation activity without interfering 6mA demethylation, indicating a prominent distinct but unclear 5mC oxidation mechanism to the conventional Tet enzymes. Here, we assessed the molecular mechanism of CcTet in catalyzing 5mC oxidation by representing the crystal structure of CcTet-5mC-dsDNA complex. We identified the distinct mechanism by which CcTet recognizes 5mC-dsDNA compared to 6mA-dsDNA substrate. Moreover, Asp337 was found to have a central role in compensating for the loss of a critical 5mC-stablizing H-bond observed in conventional Tet enzymes, and stabilizes 5mC and subsequent intermediates through an H-bond with the N4 atom of the substrates. These findings improve our understanding of Tet enzyme functions in the dsDNA 5mC and 6mA demethylation pathways, and provide useful information for future discovery of small molecular probes targeting Tet enzymes in DNA active demethylation processes.
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Affiliation(s)
- Lin Zhang
- Department of Pharmacology and Chemical Biology, State Key Laboratory of Systems Medicine for Cancer, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yajuan Mu
- Department of Pharmacology and Chemical Biology, State Key Laboratory of Systems Medicine for Cancer, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Tingting Li
- Department of Pharmacology and Chemical Biology, State Key Laboratory of Systems Medicine for Cancer, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jingyan Hu
- Department of Pharmacology and Chemical Biology, State Key Laboratory of Systems Medicine for Cancer, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Houwen Lin
- Research Centre for Marine Drugs, State Key Laboratory of Oncogene and Related Genes, Department of Pharmacy, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
- Institute of Marine Biomedicine, Shenzhen Polytechnic, Shenzhen 518055, China
| | - Liang Zhang
- Department of Pharmacology and Chemical Biology, State Key Laboratory of Systems Medicine for Cancer, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
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3
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Meng WY, Wang ZX, Zhang Y, Hou Y, Xue JH. Epigenetic marks or not? The discovery of novel DNA modifications in eukaryotes. J Biol Chem 2024; 300:106791. [PMID: 38403247 PMCID: PMC11065753 DOI: 10.1016/j.jbc.2024.106791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 01/24/2024] [Accepted: 02/04/2024] [Indexed: 02/27/2024] Open
Abstract
DNA modifications add another layer of complexity to the eukaryotic genome to regulate gene expression, playing critical roles as epigenetic marks. In eukaryotes, the study of DNA epigenetic modifications has been confined to 5mC and its derivatives for decades. However, rapid developing approaches have witnessed the expansion of DNA modification reservoirs during the past several years, including the identification of 6mA, 5gmC, 4mC, and 4acC in diverse organisms. However, whether these DNA modifications function as epigenetic marks requires careful consideration. In this review, we try to present a panorama of all the DNA epigenetic modifications in eukaryotes, emphasizing recent breakthroughs in the identification of novel DNA modifications. The characterization of their roles in transcriptional regulation as potential epigenetic marks is summarized. More importantly, the pathways for generating or eliminating these DNA modifications, as well as the proteins involved are comprehensively dissected. Furthermore, we briefly discuss the potential challenges and perspectives, which should be taken into account while investigating novel DNA modifications.
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Affiliation(s)
- Wei-Ying Meng
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Tongji Hospital affiliated to Tongji University, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Zi-Xin Wang
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Tongji Hospital affiliated to Tongji University, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Yunfang Zhang
- Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Yujun Hou
- Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China.
| | - Jian-Huang Xue
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Tongji Hospital affiliated to Tongji University, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China.
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Jiang T, Zhou Q, Yu KK, Chen SY, Li K. Identification and quantification of N6-methyladenosine by chemical derivatization coupled with 19F NMR spectroscopy. Org Biomol Chem 2024; 22:2566-2573. [PMID: 38465392 DOI: 10.1039/d4ob00169a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
N 6-Methyladenosine (6mA) is a well-known prokaryotic DNA modification that has been shown to play epigenetic roles in eukaryotic DNA. Accurate detection and quantification of 6mA are prerequisites for molecular understanding of the impact of 6mA modification on DNA. However, the existing methods have several problems, such as high false-positive rate, time-consuming and complex operating procedures. Chemical sensors for the selective detection of 6mA modification are rarely reported in the literature. Fluorinated phenylboronic acid combined with 19F NMR analysis is an effective method for determining DNA or RNA modification. In this study, we presented a simple and fast chemical method for labelling the 6th imino group of 6mA using a boric-acid-derived probe. Besides, the trifluoromethyl group of trifluoromethyl phenylboronic acid (2a) could detect 6mA modification through 19F NMR. Combined with this sensor system, 6mA modification could be detected well and quickly in 6 types of deoxynucleoside mixtures and DNA samples. Taken together, the method developed in the current study has potential for specific detection of 6mA in biological samples.
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Affiliation(s)
- Ting Jiang
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
| | - Qian Zhou
- Department of Chemistry, Xihua University, Chengdu 610039, P. R. China
| | - Kang-Kang Yu
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
| | - Shan-Yong Chen
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
| | - Kun Li
- Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
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Liu Y, Niu J, Ye F, Solberg T, Lu B, Wang C, Nowacki M, Gao S. Dynamic DNA N 6-adenine methylation (6mA) governs the encystment process, showcased in the unicellular eukaryote Pseudocohnilembus persalinus. Genome Res 2024; 34:256-271. [PMID: 38471739 PMCID: PMC10984389 DOI: 10.1101/gr.278796.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 02/14/2024] [Indexed: 03/14/2024]
Abstract
The formation of resting cysts commonly found in unicellular eukaryotes is a complex and highly regulated survival strategy against environmental stress that involves drastic physiological and biochemical changes. Although most studies have focused on the morphology and structure of cysts, little is known about the molecular mechanisms that control this process. Recent studies indicate that DNA N 6-adenine methylation (6mA) could be dynamically changing in response to external stimuli; however, its potential role in the regulation of cyst formation remains unknown. We used the ciliate Pseudocohnilembus persalinus, which can be easily induced to form cysts to investigate the dynamic pattern of 6mA in trophonts and cysts. Single-molecule real-time (SMRT) sequencing reveals high levels of 6mA in trophonts that decrease in cysts, along with a conversion of symmetric 6mA to asymmetric 6mA. Further analysis shows that 6mA, a mark of active transcription, is involved in altering the expression of encystment-related genes through changes in 6mA levels and 6mA symmetric-to-asymmetric conversion. Most importantly, we show that reducing 6mA levels by knocking down the DNA 6mA methyltransferase PpAMT1 accelerates cyst formation. Taken together, we characterize the genome-wide 6mA landscape in P. persalinus and provide insights into the role of 6mA in gene regulation under environmental stress in eukaryotes. We propose that 6mA acts as a mark of active transcription to regulate the encystment process along with symmetric-to-asymmetric conversion, providing important information for understanding the molecular response to environmental cues from the perspective of 6mA modification.
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Affiliation(s)
- Yongqiang Liu
- MOE Key Laboratory of Evolution and Marine Biodiversity and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao 266237, China
| | - Junhua Niu
- MOE Key Laboratory of Evolution and Marine Biodiversity and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao 266237, China
| | - Fei Ye
- MOE Key Laboratory of Evolution and Marine Biodiversity and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao 266237, China
| | - Therese Solberg
- Institute of Cell Biology, University of Bern, 3012 Bern, Switzerland
- Department of Molecular Biology, Keio University School of Medicine, 160-8582 Tokyo, Japan
- Human Biology Microbiome Quantum Research Center (WPI-Bio2Q), Keio University, 108-8345 Tokyo, Japan
| | - Borong Lu
- MOE Key Laboratory of Evolution and Marine Biodiversity and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao 266237, China
| | - Chundi Wang
- MOE Key Laboratory of Evolution and Marine Biodiversity and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory of Marine Protozoan Biodiversity and Evolution, Marine College, Shandong University, Weihai 264209, China
| | - Mariusz Nowacki
- Institute of Cell Biology, University of Bern, 3012 Bern, Switzerland
| | - Shan Gao
- MOE Key Laboratory of Evolution and Marine Biodiversity and Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China;
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao 266237, China
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Feng Y, Yu Z, Tang M, Li J, Peng B, Juaiti M, Tang Y, Liang B, Ouyang M, Liu Q, Song J. Transcriptome-Wide N6-Methyladenosine Alternations in Pulmonary Arteries of Monocrotaline-Induced Pulmonary Arterial Hypertension in Rats and Novel Therapeutic Targets. Biomedicines 2024; 12:364. [PMID: 38397966 PMCID: PMC10886831 DOI: 10.3390/biomedicines12020364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/24/2024] [Accepted: 01/29/2024] [Indexed: 02/25/2024] Open
Abstract
N6-methyladenosine (m6A) is a post-transcriptional epigenetic change with transcriptional stability and functionality regulated by specific m6A-modifying enzymes. However, the significance of genes modified by m6A and enzymes specific to m6A regulation in the context of pulmonary arterial hypertension (PAH) remains largely unexplored. MeRIP-seq and RNA-seq were applied to explore variances in m6A and RNA expression within the pulmonary artery tissues of control and monocrotaline-induced PAH rats. Functional enrichments were analyzed using the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. To screen candidate m6A-related genes, the STRING and Metascape databases were used to construct a protein-protein interaction network followed by a real-time PCR validation of their expression. The expression level of an m6A regulator was further investigated using immunohistochemical staining, immunofluorescence, and Western blot techniques. Additionally, proliferation assays were conducted on primary rat pulmonary artery smooth muscle cells (PASMCs). We identified forty-two differentially expressed genes that exhibited either hypermethylated or hypomethylated m6A. These genes are predominantly related to the extracellular matrix structure, MAPK, and PI3K/AKT pathways. A candidate gene, centromere protein F (CENPF), was detected with increased expression in the PAH group. Additionally, we first identified an m6A reader, leucine rich pentatricopeptide repeat containing (LRPPRC), which was downregulated in the PAH rat model. The in vitro downregulation of Lrpprc mediated by siRNA resulted in the enhanced proliferation and elevated expression of Cenpf mRNA in primary rat PASMCs. Our study revealed a modified transcriptome-wide m6A landscape and associated regulatory mechanisms in the pulmonary arteries of PAH rats, potentially offering a novel target for therapeutic strategies in the future.
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Affiliation(s)
- Yilu Feng
- Department of Cardiology, Xiangya Hospital, Central South University, Changsha 410008, China; (Y.F.); (Z.Y.); (B.P.); (M.J.); (Y.T.); (B.L.)
- Research Institute of Blood Lipid and Atherosclerosis, Central South University, Changsha 410011, China; (J.L.); (M.O.)
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Zaixin Yu
- Department of Cardiology, Xiangya Hospital, Central South University, Changsha 410008, China; (Y.F.); (Z.Y.); (B.P.); (M.J.); (Y.T.); (B.L.)
| | - Mi Tang
- Department of Cardiovascular Surgery, The Second Xiangya Hospital, Central South University, Changsha 410011, China;
| | - Jiang Li
- Research Institute of Blood Lipid and Atherosclerosis, Central South University, Changsha 410011, China; (J.L.); (M.O.)
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Baohua Peng
- Department of Cardiology, Xiangya Hospital, Central South University, Changsha 410008, China; (Y.F.); (Z.Y.); (B.P.); (M.J.); (Y.T.); (B.L.)
| | - Mukamengjiang Juaiti
- Department of Cardiology, Xiangya Hospital, Central South University, Changsha 410008, China; (Y.F.); (Z.Y.); (B.P.); (M.J.); (Y.T.); (B.L.)
| | - Yiyang Tang
- Department of Cardiology, Xiangya Hospital, Central South University, Changsha 410008, China; (Y.F.); (Z.Y.); (B.P.); (M.J.); (Y.T.); (B.L.)
| | - Benhui Liang
- Department of Cardiology, Xiangya Hospital, Central South University, Changsha 410008, China; (Y.F.); (Z.Y.); (B.P.); (M.J.); (Y.T.); (B.L.)
| | - Mingqi Ouyang
- Research Institute of Blood Lipid and Atherosclerosis, Central South University, Changsha 410011, China; (J.L.); (M.O.)
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Qingqing Liu
- Department of Respiratory and Critical Care, The Second Xiangya Hospital, Central South University, Changsha 410011, China;
| | - Jie Song
- Research Institute of Blood Lipid and Atherosclerosis, Central South University, Changsha 410011, China; (J.L.); (M.O.)
- Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha 410011, China
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Feng X, Cui X, Zhang LS, Ye C, Wang P, Zhong Y, Wu T, Zheng Z, He C. Sequencing of N 6-methyl-deoxyadenosine at single-base resolution across the mammalian genome. Mol Cell 2024; 84:596-610.e6. [PMID: 38215754 PMCID: PMC10872247 DOI: 10.1016/j.molcel.2023.12.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 07/25/2023] [Accepted: 12/13/2023] [Indexed: 01/14/2024]
Abstract
Although DNA N6-methyl-deoxyadenosine (6mA) is abundant in bacteria and protists, its presence and function in mammalian genomes have been less clear. We present Direct-Read 6mA sequencing (DR-6mA-seq), an antibody-independent method, to measure 6mA at base resolution. DR-6mA-seq employs a unique mutation-based strategy to reveal 6mA sites as misincorporation signatures without any chemical or enzymatic modulation of 6mA. We validated DR-6mA-seq through the successful mapping of the well-characterized G(6mA)TC motif in the E. coli DNA. As expected, when applying DR-6mA-seq to mammalian systems, we found that genomic DNA (gDNA) 6mA abundance is generally low in most mammalian tissues and cells; however, we did observe distinct gDNA 6mA sites in mouse testis and glioblastoma cells. DR-6mA-seq provides an enabling tool to detect 6mA at single-base resolution for a comprehensive understanding of DNA 6mA in eukaryotes.
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Affiliation(s)
- Xinran Feng
- Department of Human Genetics, The University of Chicago, Chicago, IL, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Xiaolong Cui
- Department of Chemistry, Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Li-Sheng Zhang
- Department of Chemistry, Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA; Department of Chemistry, Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Chang Ye
- Department of Chemistry, Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Pingluan Wang
- Department of Chemistry, Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Yuhao Zhong
- Department of Chemistry, Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Tong Wu
- Department of Chemistry, Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Zhong Zheng
- Department of Chemistry, Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Chuan He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA.
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8
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Zhang J, Peng Q, Ma C, Wang J, Xiao C, Li T, Liu X, Zhou L, Xu X, Zhou WZ, Ding W, An NA, Zhang L, Liu Y, Li CY. 6mA-Sniper: Quantifying 6mA sites in eukaryotes at single-nucleotide resolution. SCIENCE ADVANCES 2023; 9:eadh7912. [PMID: 37862411 PMCID: PMC10588941 DOI: 10.1126/sciadv.adh7912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 09/18/2023] [Indexed: 10/22/2023]
Abstract
While N6-methyldeoxyadenine (6mA) modification is a fundamental regulation in prokaryotes, its prevalence and functions in eukaryotes are controversial. Here, we report 6mA-Sniper to quantify 6mA sites in eukaryotes at single-nucleotide resolution, and delineate a 6mA profile in Caenorhabditis elegans with 2034 sites. Twenty-six of 39 events with Mnl I restriction endonuclease sites were verified, demonstrating the feasibility of this method. The levels of 6mA sites pinpointed by 6mA-Sniper are generally increased after Pseudomonas aeruginosa infection, but decreased in strains with the removal of METL-9, the dominant 6mA methyltransferase. The enrichment of these sites on specific motif of [GC]GAG, the selective constrains on them, and their coordinated changes with METL-9 levels thus support an active shaping of the 6mA profile by methyltransferase. Moreover, for regions marked by 6mA sites that emerged after infection, an enrichment of up-regulated genes was detected, possibly mediated through a mutual exclusive cross-talk between 6mA and H3K27me3 modification. We thus highlight 6mA regulation as a previously neglected regulator in eukaryotes.
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Affiliation(s)
- Jie Zhang
- State Key Laboratory of Protein and Plant Gene Research, Laboratory of Bioinformatics and Genomic Medicine, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Qi Peng
- State Key Laboratory of Protein and Plant Gene Research, Laboratory of Bioinformatics and Genomic Medicine, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Chengchuan Ma
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
- Beijing Advanced Innovation Center for Genomics, Beijing 100871, China
| | - Jiaxin Wang
- State Key Laboratory of Protein and Plant Gene Research, Laboratory of Bioinformatics and Genomic Medicine, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Chunfu Xiao
- State Key Laboratory of Protein and Plant Gene Research, Laboratory of Bioinformatics and Genomic Medicine, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Ting Li
- State Key Laboratory of Protein and Plant Gene Research, Laboratory of Bioinformatics and Genomic Medicine, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Xiaoge Liu
- State Key Laboratory of Protein and Plant Gene Research, Laboratory of Bioinformatics and Genomic Medicine, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Liankui Zhou
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Xinwei Xu
- State Key Laboratory of Protein and Plant Gene Research, Laboratory of Bioinformatics and Genomic Medicine, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Wei-Zhen Zhou
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wanqiu Ding
- State Key Laboratory of Protein and Plant Gene Research, Laboratory of Bioinformatics and Genomic Medicine, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
- Bioinformatics Core, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Ni A. An
- State Key Laboratory of Protein and Plant Gene Research, Laboratory of Bioinformatics and Genomic Medicine, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
| | - Li Zhang
- Chinese Institute for Brain Research, Beijing, China
| | - Ying Liu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
- Beijing Advanced Innovation Center for Genomics, Beijing 100871, China
| | - Chuan-Yun Li
- State Key Laboratory of Protein and Plant Gene Research, Laboratory of Bioinformatics and Genomic Medicine, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100871, China
- Chinese Institute for Brain Research, Beijing, China
- Southwest United Graduate School, Kunming 650092, China
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9
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Febrimarsa, Gornik SG, Barreira SN, Salinas‐Saavedra M, Schnitzler CE, Baxevanis AD, Frank U. Randomly incorporated genomic N6-methyldeoxyadenosine delays zygotic transcription initiation in a cnidarian. EMBO J 2023; 42:e112934. [PMID: 37708295 PMCID: PMC10390872 DOI: 10.15252/embj.2022112934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 09/16/2023] Open
Abstract
N6-methyldeoxyadenosine (6mA) is a chemical alteration of DNA, observed across all realms of life. Although the functions of 6mA are well understood in bacteria and protists, its roles in animal genomes have been controversial. We show that 6mA randomly accumulates in early embryos of the cnidarian Hydractinia symbiolongicarpus, with a peak at the 16-cell stage followed by clearance to background levels two cell cycles later, at the 64-cell stage-the embryonic stage at which zygotic genome activation occurs in this animal. Knocking down Alkbh1, a putative initiator of animal 6mA clearance, resulted in higher levels of 6mA at the 64-cell stage and a delay in the initiation of zygotic transcription. Our data are consistent with 6mA originating from recycled nucleotides of degraded m6A-marked maternal RNA postfertilization. Therefore, while 6mA does not function as an epigenetic mark in Hydractinia, its random incorporation into the early embryonic genome inhibits transcription. In turn, Alkbh1 functions as a genomic 6mA "cleaner," facilitating timely zygotic genome activation. Given the random nature of genomic 6mA accumulation and its ability to interfere with gene expression, defects in 6mA clearance may represent a hitherto unknown cause of various pathologies.
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Affiliation(s)
- Febrimarsa
- Centre for Chromosome Biology, School of Biological and Chemical SciencesUniversity of GalwayGalwayRepublic of Ireland
| | - Sebastian G Gornik
- Centre for Chromosome Biology, School of Biological and Chemical SciencesUniversity of GalwayGalwayRepublic of Ireland
- Present address:
Centre for Organismal StudiesHeidelberg UniversityHeidelbergGermany
| | - Sofia N Barreira
- Computational and Statistical Genomics Branch, Division of Intramural ResearchNational Human Genome Research Institute, National Institutes of HealthBethesdaMDUSA
| | - Miguel Salinas‐Saavedra
- Centre for Chromosome Biology, School of Biological and Chemical SciencesUniversity of GalwayGalwayRepublic of Ireland
| | - Christine E Schnitzler
- Whitney Laboratory for Marine BioscienceUniversity of FloridaSt. AugustineFLUSA
- Department of BiologyUniversity of FloridaGainesvilleFLUSA
| | - Andreas D Baxevanis
- Computational and Statistical Genomics Branch, Division of Intramural ResearchNational Human Genome Research Institute, National Institutes of HealthBethesdaMDUSA
| | - Uri Frank
- Centre for Chromosome Biology, School of Biological and Chemical SciencesUniversity of GalwayGalwayRepublic of Ireland
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10
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Zhou J, Horton JR, Kaur G, Chen Q, Li X, Mendoza F, Wu T, Blumenthal RM, Zhang X, Cheng X. Biochemical and structural characterization of the first-discovered metazoan DNA cytosine-N4 methyltransferase from the bdelloid rotifer Adineta vaga. J Biol Chem 2023; 299:105017. [PMID: 37414145 PMCID: PMC10406627 DOI: 10.1016/j.jbc.2023.105017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/27/2023] [Accepted: 06/29/2023] [Indexed: 07/08/2023] Open
Abstract
Much is known about the generation, removal, and roles of 5-methylcytosine (5mC) in eukaryote DNA, and there is a growing body of evidence regarding N6-methyladenine, but very little is known about N4-methylcytosine (4mC) in the DNA of eukaryotes. The gene for the first metazoan DNA methyltransferase generating 4mC (N4CMT) was reported and characterized recently by others, in tiny freshwater invertebrates called bdelloid rotifers. Bdelloid rotifers are ancient, apparently asexual animals, and lack canonical 5mC DNA methyltransferases. Here, we characterize the kinetic properties and structural features of the catalytic domain of the N4CMT protein from the bdelloid rotifer Adineta vaga. We find that N4CMT generates high-level methylation at preferred sites, (a/c)CG(t/c/a), and low-level methylation at disfavored sites, exemplified by ACGG. Like the mammalian de novo 5mC DNA methyltransferase 3A/3B (DNMT3A/3B), N4CMT methylates CpG dinucleotides on both DNA strands, generating hemimethylated intermediates and eventually fully methylated CpG sites, particularly in the context of favored symmetric sites. In addition, like DNMT3A/3B, N4CMT methylates non-CpG sites, mainly CpA/TpG, though at a lower rate. Both N4CMT and DNMT3A/3B even prefer similar CpG-flanking sequences. Structurally, the catalytic domain of N4CMT closely resembles the Caulobacter crescentus cell cycle-regulated DNA methyltransferase. The symmetric methylation of CpG, and similarity to a cell cycle-regulated DNA methyltransferase, together suggest that N4CMT might also carry out DNA synthesis-dependent methylation following DNA replication.
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Affiliation(s)
- Jujun Zhou
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Gundeep Kaur
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Qin Chen
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Xuwen Li
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Fabian Mendoza
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Tao Wu
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA.
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
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11
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Chen S, Lai W, Li Y, Liu Y, Jiang J, Li X, Jiang G, Wang H. Aberrant DNA N 6 -methyladenine incorporation via adenylate kinase 1 is suppressed by ADAL deaminase-dependent 2'-deoxynucleotide pool sanitation. EMBO J 2023; 42:e113684. [PMID: 37366109 PMCID: PMC10390868 DOI: 10.15252/embj.2023113684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 05/30/2023] [Accepted: 06/15/2023] [Indexed: 06/28/2023] Open
Abstract
Intracellular decay of N6 -methyladenine (m6A)-containing RNA potentially induces aberrant N6 -methyl-2'-adenine (6mdA) misincorporation into DNA. Biophysically, misincorporated 6mdA may destabilize the DNA duplex in a manner similar to bona fide methylated 6mdA DNA, thereby affecting DNA replication and transcription. Utilizing heavy stable isotope labeling and ultrasensitive UHPLC-MS/MS assay, we demonstrate that intracellular m6A-RNA decay does not generate free 6mdA species, nor lead to any misincorporated DNA 6mdA in most mammalian cell lines tested, unveiling the existence of a sanitation mechanism that prevents 6mdA misincorporation. Depletion of deaminase ADAL increases the levels of free 6mdA species, concomitant with the presence of DNA-misincorporated 6mdA resulting from intracellular RNA m6A decay, suggesting that ADAL catabolizes 6mdAMP in vivo. Furthermore, we show that the overexpression of adenylate kinase 1 (AK1) promotes 6mdA misincorporation, while AK1 knockdown diminishes 6mdA incorporation, in ADAL-deficient cells. We conclude that ADAL together with other factors (such as MTH1) contributes to 2'-deoxynucleotide pool sanitation in most cells but compromised sanitation (e.g., in NIH3T3 cells) and increased AK1 expression may facilitate aberrant 6mdA incorporation. This sanitation mechanism may provide a framework for the maintenance of the epigenetic 6mdA landscape.
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Affiliation(s)
- Shaokun Chen
- The State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco‐Environmental SciencesChinese Academy of SciencesBeijingChina
- School of Chemical SciencesUniversity of Chinese Academy of SciencesBeijingChina
| | - Weiyi Lai
- The State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco‐Environmental SciencesChinese Academy of SciencesBeijingChina
| | - Yanan Li
- Institute of Environment and Health, Institute for Advanced StudyUCASHangzhouChina
| | - Yan Liu
- The State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco‐Environmental SciencesChinese Academy of SciencesBeijingChina
| | - Jie Jiang
- Shenzhen Center for Disease Control and PreventionShenzhenChina
| | - Xiangjun Li
- School of Chemical SciencesUniversity of Chinese Academy of SciencesBeijingChina
| | - Guibin Jiang
- The State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco‐Environmental SciencesChinese Academy of SciencesBeijingChina
- Institute of Environment and Health, Institute for Advanced StudyUCASHangzhouChina
| | - Hailin Wang
- The State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco‐Environmental SciencesChinese Academy of SciencesBeijingChina
- Institute of Environment and Health, Institute for Advanced StudyUCASHangzhouChina
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12
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Arkhipova IR, Yushenova IA, Rodriguez F. Shaping eukaryotic epigenetic systems by horizontal gene transfer. Bioessays 2023; 45:e2200232. [PMID: 37339822 PMCID: PMC10287040 DOI: 10.1002/bies.202200232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 05/07/2023] [Accepted: 05/08/2023] [Indexed: 06/22/2023]
Abstract
DNA methylation constitutes one of the pillars of epigenetics, relying on covalent bonds for addition and/or removal of chemically distinct marks within the major groove of the double helix. DNA methyltransferases, enzymes which introduce methyl marks, initially evolved in prokaryotes as components of restriction-modification systems protecting host genomes from bacteriophages and other invading foreign DNA. In early eukaryotic evolution, DNA methyltransferases were horizontally transferred from bacteria into eukaryotes several times and independently co-opted into epigenetic regulatory systems, primarily via establishing connections with the chromatin environment. While C5-methylcytosine is the cornerstone of plant and animal epigenetics and has been investigated in much detail, the epigenetic role of other methylated bases is less clear. The recent addition of N4-methylcytosine of bacterial origin as a metazoan DNA modification highlights the prerequisites for foreign gene co-option into the host regulatory networks, and challenges the existing paradigms concerning the origin and evolution of eukaryotic regulatory systems.
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Affiliation(s)
- Irina R Arkhipova
- Marine Biological Laboratory, Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Woods Hole, Massachusetts, USA
| | - Irina A Yushenova
- Marine Biological Laboratory, Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Woods Hole, Massachusetts, USA
| | - Fernando Rodriguez
- Marine Biological Laboratory, Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Woods Hole, Massachusetts, USA
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13
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Kong Y, Mead EA, Fang G. Navigating the pitfalls of mapping DNA and RNA modifications. Nat Rev Genet 2023; 24:363-381. [PMID: 36653550 PMCID: PMC10722219 DOI: 10.1038/s41576-022-00559-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2022] [Indexed: 01/19/2023]
Abstract
Chemical modifications to nucleic acids occur across the kingdoms of life and carry important regulatory information. Reliable high-resolution mapping of these modifications is the foundation of functional and mechanistic studies, and recent methodological advances based on next-generation sequencing and long-read sequencing platforms are critical to achieving this aim. However, mapping technologies may have limitations that sometimes lead to inconsistent results. Some of these limitations are technical in nature and specific to certain types of technology. Here, however, we focus on common (yet not always widely recognized) pitfalls that are shared among frequently used mapping technologies and discuss strategies to help technology developers and users mitigate their effects. Although the emphasis is primarily on DNA modifications, RNA modifications are also discussed.
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Affiliation(s)
- Yimeng Kong
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Edward A Mead
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Gang Fang
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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14
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Pan B, Ye F, Li T, Wei F, Warren A, Wang Y, Gao S. Potential role of N 6-adenine DNA methylation in alternative splicing and endosymbiosis in Paramecium bursaria. iScience 2023; 26:106676. [PMID: 37182097 PMCID: PMC10173741 DOI: 10.1016/j.isci.2023.106676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 12/02/2022] [Accepted: 04/11/2023] [Indexed: 05/16/2023] Open
Abstract
N6-adenine DNA methylation (6mA), a rediscovered epigenetic mark in eukaryotic organisms, diversifies in abundance, distribution, and function across species, necessitating its study in more taxa. Paramecium bursaria is a typical model organism with endosymbiotic algae of the species Chlorella variabilis. This consortium therefore serves as a valuable system to investigate the functional role of 6mA in endosymbiosis, as well as the evolutionary importance of 6mA among eukaryotes. In this study, we report the first genome-wide, base pair-resolution map of 6mA in P. bursaria and identify its methyltransferase PbAMT1. Functionally, 6mA exhibits a bimodal distribution at the 5' end of RNA polymerase II-transcribed genes and possibly participates in transcription by facilitating alternative splicing. Evolutionarily, 6mA co-evolves with gene age and likely serves as a reverse mark of endosymbiosis-related genes. Our results offer new insights for the functional diversification of 6mA in eukaryotes as an important epigenetic mark.
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Affiliation(s)
- Bo Pan
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao 266237, China
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Science, Ocean University of China, Qingdao 266003, China
| | - Fei Ye
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao 266237, China
| | - Tao Li
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao 266237, China
| | - Fan Wei
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao 266237, China
| | - Alan Warren
- Department of Life Sciences, Natural History Museum, London SW7 5BD, UK
| | - Yuanyuan Wang
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao 266237, China
- Corresponding author
| | - Shan Gao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao 266237, China
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Science, Ocean University of China, Qingdao 266003, China
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15
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Debo BM, Mallory BJ, Stergachis AB. Evaluation of N 6-methyldeoxyadenosine antibody-based genomic profiling in eukaryotes. Genome Res 2023; 33:427-434. [PMID: 36788024 PMCID: PMC10078290 DOI: 10.1101/gr.276696.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 02/02/2023] [Indexed: 02/16/2023]
Abstract
Low-level DNA N 6-methyldeoxyadenosine (DNA-m6A) has recently been reported across various eukaryotes. Although anti-m6A antibody-based approaches are commonly used to measure DNA-m6A levels, this approach is known to be confounded by DNA secondary structures, RNA contamination, and bacterial contamination. To evaluate for these confounding features, we introduce an approach for systematically validating the selectivity of antibody-based DNA-m6A methods and use a highly selective anti-DNA-m6A antibody to reexamine patterns of DNA-m6A in C. reinhardtii, A. thaliana, and D. melanogaster Our findings raise caution about the use of antibody-based methods for endogenous m6A quantification and mapping in eukaryotes.
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Affiliation(s)
- Brian M Debo
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Benjamin J Mallory
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
| | - Andrew B Stergachis
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA;
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, Washington 98195-7720, USA
- Brotman Baty Institute for Precision Medicine, Seattle, Washington 98195, USA
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16
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Lu MW, Beh LY, Yerlici VT, Fang W, Kulej K, Garcia BA, Landweber LF. Exploration of the Nuclear Proteomes in the Ciliate Oxytricha trifallax. Microorganisms 2023; 11:microorganisms11020343. [PMID: 36838311 PMCID: PMC9958989 DOI: 10.3390/microorganisms11020343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/17/2023] [Accepted: 01/21/2023] [Indexed: 01/31/2023] Open
Abstract
Nuclear dimorphism is a fundamental feature of ciliated protozoa, which have separate somatic and germline genomes in two distinct organelles within a single cell. The transcriptionally active somatic genome, contained within the physically larger macronucleus, is both structurally and functionally different from the silent germline genome housed in the smaller micronucleus. This difference in genome architecture is particularly exaggerated in Oxytricha trifallax, in which the somatic genome comprises tens of thousands of gene-sized nanochromosomes maintained at a high and variable ploidy, while the germline has a diploid set of megabase-scale chromosomes. To examine the compositional differences between the nuclear structures housing the genomes, we performed a proteomic survey of both types of nuclei and of macronuclear histones using quantitative mass spectrometry. We note distinct differences between the somatic and germline nuclei, with many functional proteins being highly enriched in one of the two nuclei. To validate our conclusions and the efficacy of nuclear separation, we used protein localization through a combination of transformations and immunofluorescence. We also note that the macronuclear histones strikingly display only activating marks, consistent with the conclusion that the macronucleus is the hub of transcription. These observations suggest that the compartmentalization of different genome features into separate structures has been accompanied by a similar specialization of nuclear components that maintain and facilitate the functions of the genomes specific to each nucleus.
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Affiliation(s)
- Michael W. Lu
- Department of Biological Sciences, Columbia University, New York, NY 10025, USA
| | - Leslie Y. Beh
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - V. Talya Yerlici
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Wenwen Fang
- RNA Therapeutics Institute, UMass Chan Medical School, Worcester, MA 01655, USA
| | - Katarzyna Kulej
- Division of Protective Immunity and Division of Cancer Pathobiology, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Benjamin A. Garcia
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Laura F. Landweber
- Department of Biological Sciences, Columbia University, New York, NY 10025, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
- Correspondence:
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17
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Structural insights into DNA N 6-adenine methylation by the MTA1 complex. Cell Discov 2023; 9:8. [PMID: 36658132 PMCID: PMC9852454 DOI: 10.1038/s41421-022-00516-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 12/30/2022] [Indexed: 01/21/2023] Open
Abstract
N6-methyldeoxyadenine (6mA) has recently been reported as a prevalent DNA modification in eukaryotes. The Tetrahymena thermophila MTA1 complex consisting of four subunits, namely MTA1, MTA9, p1, and p2, is the first identified eukaryotic 6mA methyltransferase (MTase) complex. Unlike the prokaryotic 6mA MTases which have been biochemically and structurally characterized, the operation mode of the MTA1 complex remains largely elusive. Here, we report the cryogenic electron microscopy structures of the quaternary MTA1 complex in S-adenosyl methionine (SAM)-bound (2.6 Å) and S-adenosyl homocysteine (SAH)-bound (2.8 Å) states. Using an AI-empowered integrative approach based on AlphaFold prediction and chemical cross-linking mass spectrometry, we further modeled a near-complete structure of the quaternary complex. Coupled with biochemical characterization, we revealed that MTA1 serves as the catalytic core, MTA1, MTA9, and p1 likely accommodate the substrate DNA, and p2 may facilitate the stabilization of MTA1. These results together offer insights into the molecular mechanism underpinning methylation by the MTA1 complex and the potential diversification of MTases for N6-adenine methylation.
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18
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Hsu KW, Lai JCY, Chang JS, Peng PH, Huang CH, Lee DY, Tsai YC, Chung CJ, Chang H, Chang CH, Chen JL, Pang ST, Hao Z, Cui XL, He C, Wu KJ. METTL4-mediated nuclear N6-deoxyadenosine methylation promotes metastasis through activating multiple metastasis-inducing targets. Genome Biol 2022; 23:249. [PMID: 36461076 PMCID: PMC9716733 DOI: 10.1186/s13059-022-02819-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 11/23/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND DNA N6-methyldeoxyadenosine (6mA) is rarely present in mammalian cells and its nuclear role remains elusive. RESULTS Here we show that hypoxia induces nuclear 6mA modification through a DNA methyltransferase, METTL4, in hypoxia-induced epithelial-mesenchymal transition (EMT) and tumor metastasis. Co-expression of METTL4 and 6mA represents a prognosis marker for upper tract urothelial cancer patients. By RNA sequencing and 6mA chromatin immunoprecipitation-exonuclease digestion followed by sequencing, we identify lncRNA RP11-390F4.3 and one novel HIF-1α co-activator, ZMIZ1, that are co-regulated by hypoxia and METTL4. Other genes involved in hypoxia-mediated phenotypes are also regulated by 6mA modification. Quantitative chromatin isolation by RNA purification assay shows the occupancy of lncRNA RP11-390F4.3 on the promoters of multiple EMT regulators, indicating lncRNA-chromatin interaction. Knockdown of lncRNA RP11-390F4.3 abolishes METTL4-mediated tumor metastasis. We demonstrate that ZMIZ1 is an essential co-activator of HIF-1α. CONCLUSIONS We show that hypoxia results in enriched 6mA levels in mammalian tumor cells through METTL4. This METTL4-mediated nuclear 6mA deposition induces tumor metastasis through activating multiple metastasis-inducing genes. METTL4 is characterized as a potential therapeutic target in hypoxic tumors.
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Affiliation(s)
- Kai-Wen Hsu
- Cancer Genome Research Center, Chang Gung Memorial Hospital at Linkou, No. 15, Wenhua 1st Road, Gueishan Dist., Taoyuan, 333 Taiwan ,Research Center for Cancer Biology, Taipei, Taiwan ,grid.254145.30000 0001 0083 6092Institute of Translational Medicine and New Drug Development, China Medical University, Taichung, 404 Taiwan
| | - Joseph Chieh-Yu Lai
- Cancer Genome Research Center, Chang Gung Memorial Hospital at Linkou, No. 15, Wenhua 1st Road, Gueishan Dist., Taoyuan, 333 Taiwan ,grid.254145.30000 0001 0083 6092Institute of Biomedical Sciences, China Medical University, Taichung, 404 Taiwan
| | - Jeng-Shou Chang
- Cancer Genome Research Center, Chang Gung Memorial Hospital at Linkou, No. 15, Wenhua 1st Road, Gueishan Dist., Taoyuan, 333 Taiwan
| | - Pei-Hua Peng
- Cancer Genome Research Center, Chang Gung Memorial Hospital at Linkou, No. 15, Wenhua 1st Road, Gueishan Dist., Taoyuan, 333 Taiwan
| | - Ching-Hui Huang
- Cancer Genome Research Center, Chang Gung Memorial Hospital at Linkou, No. 15, Wenhua 1st Road, Gueishan Dist., Taoyuan, 333 Taiwan
| | - Der-Yen Lee
- grid.254145.30000 0001 0083 6092Institute of Integrated Medicine, China Medical University, Taichung, 404 Taiwan
| | | | - Chi-Jung Chung
- grid.254145.30000 0001 0083 6092Department of Health Risk Management, College of Public Health, China Medical University, Taichung, 404 Taiwan
| | - Han Chang
- grid.411508.90000 0004 0572 9415Department of Pathology, China Medical University Hospital, Taichung, 404 Taiwan
| | - Chao-Hsiang Chang
- grid.411508.90000 0004 0572 9415Department of Urology, China Medical University Hospital, Taichung, 404 Taiwan
| | - Ji-Lin Chen
- grid.278247.c0000 0004 0604 5314Comprehensive Breast Health Center, Taipei Veterans General Hospital, Taipei, 112 Taiwan
| | - See-Tong Pang
- Division of Urology, Department of Surgery, Chang Gung Memorial Hospital at Linkou, Taoyuan, 333 Taiwan
| | - Ziyang Hao
- grid.170205.10000 0004 1936 7822Departments of Chemistry & Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, 929 E. 57th St., Chicago, IL 60637 USA ,grid.24696.3f0000 0004 0369 153XSchool of Pharmaceutical Sciences, Capital Medical University, Beijing, 100069 China
| | - Xiao-Long Cui
- grid.170205.10000 0004 1936 7822Departments of Chemistry & Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, 929 E. 57th St., Chicago, IL 60637 USA
| | - Chuan He
- grid.170205.10000 0004 1936 7822Departments of Chemistry & Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, 929 E. 57th St., Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822Howard Hughes Medical Institute, The University of Chicago, 929 E. 57th St., Chicago, IL 60637 USA
| | - Kou-Juey Wu
- Cancer Genome Research Center, Chang Gung Memorial Hospital at Linkou, No. 15, Wenhua 1st Road, Gueishan Dist., Taoyuan, 333 Taiwan
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19
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Li N, Meng G, Yang C, Li H, Liu L, Wu Y, Liu B. Changes in epigenetic information during the occurrence and development of gastric cancer. Int J Biochem Cell Biol 2022; 153:106315. [DOI: 10.1016/j.biocel.2022.106315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 09/22/2022] [Accepted: 10/18/2022] [Indexed: 11/24/2022]
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Cui YH, Wilkinson E, Peterson J, He YY. ALKBH4 Stabilization Is Required for Arsenic-Induced 6mA DNA Methylation Inhibition, Keratinocyte Malignant Transformation, and Tumorigenicity. WATER 2022; 14:3595. [PMID: 37207134 PMCID: PMC10194016 DOI: 10.3390/w14223595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Inorganic arsenic is one of the well-known human skin carcinogens. However, the molecular mechanism by which arsenic promotes carcinogenesis remains unclear. Previous studies have established that epigenetic changes, including changes in DNA methylation, are among the critical mechanisms that drive carcinogenesis. N6-methyladenine (6mA) methylation on DNA is a widespread epigenetic modification that was initially found on bacterial and phage DNA. Only recently has 6mA been identified in mammalian genomes. However, the function of 6mA in gene expression and cancer development is not well understood. Here, we show that chronic low doses of arsenic induce malignant transformation and tumorigenesis in keratinocytes and lead to the upregulation of ALKBH4 and downregulation of 6mA on DNA. We found that reduced 6mA levels in response to low levels of arsenic were mediated by the upregulation of the 6mA DNA demethylase ALKBH4. Moreover, we found that arsenic increased ALKBH4 protein levels and that ALKBH4 deletion impaired arsenic-induced tumorigenicity in vitro and in mice. Mechanistically, we found that arsenic promoted ALKBH4 protein stability through reduced autophagy. Together, our findings reveal that the DNA 6mA demethylaseALKBH4 promotes arsenic tumorigenicity and establishes ALKBH4 as a promising target for arsenic-induced tumorigenesis.
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Affiliation(s)
- Yan-Hong Cui
- Section of Dermatology, Department of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Emma Wilkinson
- Section of Dermatology, Department of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Jack Peterson
- The College, Biological Science Division, University of Chicago, Chicago, IL 60637, USA
| | - Yu-Ying He
- Section of Dermatology, Department of Medicine, University of Chicago, Chicago, IL 60637, USA
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21
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ENet-6mA: Identification of 6mA Modification Sites in Plant Genomes Using ElasticNet and Neural Networks. Int J Mol Sci 2022; 23:ijms23158314. [PMID: 35955447 PMCID: PMC9369089 DOI: 10.3390/ijms23158314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/22/2022] [Accepted: 07/24/2022] [Indexed: 02/01/2023] Open
Abstract
N6-methyladenine (6mA) has been recognized as a key epigenetic alteration that affects a variety of biological activities. Precise prediction of 6mA modification sites is essential for understanding the logical consistency of biological activity. There are various experimental methods for identifying 6mA modification sites, but in silico prediction has emerged as a potential option due to the very high cost and labor-intensive nature of experimental procedures. Taking this into consideration, developing an efficient and accurate model for identifying N6-methyladenine is one of the top objectives in the field of bioinformatics. Therefore, we have created an in silico model for the classification of 6mA modifications in plant genomes. ENet-6mA uses three encoding methods, including one-hot, nucleotide chemical properties (NCP), and electron–ion interaction potential (EIIP), which are concatenated and fed as input to ElasticNet for feature reduction, and then the optimized features are given directly to the neural network to get classified. We used a benchmark dataset of rice for five-fold cross-validation testing and three other datasets from plant genomes for cross-species testing purposes. The results show that the model can predict the N6-methyladenine sites very well, even cross-species. Additionally, we separated the datasets into different ratios and calculated the performance using the area under the precision–recall curve (AUPRC), achieving 0.81, 0.79, and 0.50 with 1:10 (positive:negative) samples for F. vesca, R. chinensis, and A. thaliana, respectively.
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22
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Lynch M, Schavemaker PE, Licknack TJ, Hao Y, Pezzano A. Evolutionary bioenergetics of ciliates. J Eukaryot Microbiol 2022; 69:e12934. [PMID: 35778890 DOI: 10.1111/jeu.12934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/23/2022] [Accepted: 06/08/2022] [Indexed: 10/17/2022]
Abstract
Understanding why various organisms evolve alternative ways of living requires information on both the fitness advantages of phenotypic modifications and the costs of constructing and operating cellular features. Although the former has been the subject of a myriad of ecological studies, almost no attention has been given to how organisms allocate resources to alternative structures and functions. We address these matters by capitalizing on an array of observations on diverse ciliate species and from the emerging field of evolutionary bioenergetics. A relatively robust and general estimator for the total cost of a cell per cell cycle (in units of ATP equivalents) is provided, and this is then used to understand how the magnitudes of various investments scale with cell size. Among other things, we examine the costs associated with the large macronuclear genomes of ciliates, as well as ribosomes, various internal membranes, osmoregulation, cilia, and swimming activities. Although a number of uncertainties remain, the general approach taken may serve as blueprint for expanding this line of work to additional traits and phylogenetic lineages.
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Affiliation(s)
- Michael Lynch
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ
| | - Paul E Schavemaker
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ
| | - Timothy J Licknack
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ
| | - Yue Hao
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ
| | - Arianna Pezzano
- Ira A. Fulton Schools of Engineering, School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ
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Miao Z, Wang G, Shen H, Wang X, Gabriel DW, Liang W. BcMettl4-Mediated DNA Adenine N6-Methylation Is Critical for Virulence of Botrytis cinerea. Front Microbiol 2022; 13:925868. [PMID: 35847085 PMCID: PMC9279130 DOI: 10.3389/fmicb.2022.925868] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 05/23/2022] [Indexed: 11/13/2022] Open
Abstract
DNA adenine N6-methylation (6mA) plays a critical role in various biological functions, but its occurrence and functions in filamentous plant pathogens are largely unexplored. Botrytis cinerea is an important pathogenic fungus worldwide. A systematic analysis of 6mA in B. cinerea was performed in this study, revealing that 6mA is widely distributed in the genome of this fungus. The 2 kb regions flanking many genes, particularly the upstream promoter regions, were susceptible to methylation. The role of BcMettl4, a 6mA methyltransferase, in the virulence of B. cinerea was investigated. BcMETTL4 disruption and point mutations of its catalytic motif “DPPW” both resulted in significant 6mA reduction in the genomic DNA and in reduced virulence of B. cinerea. RNA-Seq analysis revealed a total of 13 downregulated genes in the disruption mutant ΔBcMettl4 in which methylation occurred at the promoter sites. These were involved in oxidoreduction, secretory pathways, autophagy and carbohydrate metabolism. Two of these genes, BcFDH and BcMFS2, were independently disrupted. Knockout of BcFDH led to reduced sclerotium formation, while disruption of BcMFS2 resulted in dramatically decreased conidium formation and pathogenicity. These observations indicated that 6mA provides potential epigenetic markers in B. cinerea and that BcMettl4 regulates virulence in this important plant pathogen.
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Affiliation(s)
- Zhengang Miao
- College of Plant Health and Medicine, Engineering Research Center for Precision Pest Management for Fruits and Vegetables of Qingdao, Shandong Engineering Research Center for Environment-Friendly Agricultural Pest Management, Shandong Province Key Laboratory of Applied Mycology, Qingdao Agricultural University, Qingdao, China
| | - Guangyuan Wang
- College of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, Qingdao Agricultural University, Qingdao, China
| | - Heng Shen
- College of Plant Health and Medicine, Engineering Research Center for Precision Pest Management for Fruits and Vegetables of Qingdao, Shandong Engineering Research Center for Environment-Friendly Agricultural Pest Management, Shandong Province Key Laboratory of Applied Mycology, Qingdao Agricultural University, Qingdao, China
| | - Xue Wang
- Yantai Agricultural Technology Extension Center, Yantai, China
| | - Dean W. Gabriel
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States
| | - Wenxing Liang
- College of Plant Health and Medicine, Engineering Research Center for Precision Pest Management for Fruits and Vegetables of Qingdao, Shandong Engineering Research Center for Environment-Friendly Agricultural Pest Management, Shandong Province Key Laboratory of Applied Mycology, Qingdao Agricultural University, Qingdao, China
- *Correspondence: Wenxing Liang,
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Li H, Zhang N, Wang Y, Xia S, Zhu Y, Xing C, Tian X, Du Y. DNA N6-Methyladenine Modification in Eukaryotic Genome. Front Genet 2022; 13:914404. [PMID: 35812743 PMCID: PMC9263368 DOI: 10.3389/fgene.2022.914404] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/08/2022] [Indexed: 11/18/2022] Open
Abstract
DNA methylation is treated as an important epigenetic mark in various biological activities. In the past, a large number of articles focused on 5 mC while lacking attention to N6-methyladenine (6 mA). The presence of 6 mA modification was previously discovered only in prokaryotes. Recently, with the development of detection technologies, 6 mA has been found in several eukaryotes, including protozoans, metazoans, plants, and fungi. The importance of 6 mA in prokaryotes and single-celled eukaryotes has been widely accepted. However, due to the incredibly low density of 6 mA and restrictions on detection technologies, the prevalence of 6 mA and its role in biological processes in eukaryotic organisms are highly debated. In this review, we first summarize the advantages and disadvantages of 6 mA detection methods. Then, we conclude existing reports on the prevalence of 6 mA in eukaryotic organisms. Next, we highlight possible methyltransferases, demethylases, and the recognition proteins of 6 mA. In addition, we summarize the functions of 6 mA in eukaryotes. Last but not least, we summarize our point of view and put forward the problems that need further research.
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Affiliation(s)
- Hao Li
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- First School of Clinical Medicine, Anhui Medical University, Hefei, China
- First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Ning Zhang
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- First School of Clinical Medicine, Anhui Medical University, Hefei, China
- First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Yuechen Wang
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- Second School of Clinical Medicine, Anhui Medical University, Hefei, China
| | - Siyuan Xia
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- Second School of Clinical Medicine, Anhui Medical University, Hefei, China
| | - Yating Zhu
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Chen Xing
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Xuefeng Tian
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- First School of Clinical Medicine, Anhui Medical University, Hefei, China
| | - Yinan Du
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- *Correspondence: Yinan Du,
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25
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Jiménez-Ramírez IA, Pijeira-Fernández G, Moreno-Cálix DM, De-la-Peña C. Same modification, different location: the mythical role of N 6-adenine methylation in plant genomes. PLANTA 2022; 256:9. [PMID: 35696004 DOI: 10.1007/s00425-022-03926-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/23/2022] [Indexed: 06/15/2023]
Abstract
The present review summarizes recent advances in the understanding of 6mA in DNA as an emergent epigenetic mark with distinctive characteristics, discusses its importance in plant genomes, and highlights its chemical nature and functions. Adenine methylation is an epigenetic modification present in DNA (6mA) and RNA (m6A) that has a regulatory function in many cellular processes. This modification occurs through a reversible reaction that covalently binds a methyl group, usually at the N6 position of the purine ring. This modification carries biophysical properties that affect the stability of nucleic acids as well as their binding affinity with other molecules. DNA 6mA has been related to genome stability, gene expression, DNA replication, and repair mechanisms. Recent advances have shown that 6mA in plant genomes is related to development and stress response. In this review, we present recent advances in the understanding of 6mA in DNA as an emergent epigenetic mark with distinctive characteristics. We discuss the key elements of this modification, focusing mainly on its importance in plant genomes. Furthermore, we highlight its chemical nature and the regulatory effects that it exerts on gene expression and plant development. Finally, we emphasize the functions of 6mA in photosynthesis, stress, and flowering.
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Affiliation(s)
- Irma A Jiménez-Ramírez
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, Calle 43 No. 130 x 32 y 34. Col. Chuburná de Hidalgo, 97205, Mérida, Yucatán, Mexico
| | - Gema Pijeira-Fernández
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, Calle 43 No. 130 x 32 y 34. Col. Chuburná de Hidalgo, 97205, Mérida, Yucatán, Mexico
| | - Delia M Moreno-Cálix
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, Calle 43 No. 130 x 32 y 34. Col. Chuburná de Hidalgo, 97205, Mérida, Yucatán, Mexico
| | - Clelia De-la-Peña
- Centro de Investigación Científica de Yucatán, Unidad de Biotecnología, Calle 43 No. 130 x 32 y 34. Col. Chuburná de Hidalgo, 97205, Mérida, Yucatán, Mexico.
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26
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Zhang G, Diao S, Song Y, He C, Zhang J. Genome-wide DNA N6-adenine methylation in sea buckthorn (Hippophae rhamnoides L.) fruit development. TREE PHYSIOLOGY 2022; 42:1286-1295. [PMID: 34986489 DOI: 10.1093/treephys/tpab177] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/24/2021] [Indexed: 06/14/2023]
Abstract
As a new epigenetic mark, DNA N6-adenine (6mA) methylation plays an important role in various biological processes and has been reported in many prokaryotic organisms in recent years. However, the distribution patterns and functions of DNA 6mA modification have been poorly studied in non-model crops. In this study, we observed that the methylation ratio of 6mA was about 0.016% in the sea buckthorn (Hippophae rhamnoides L.) genome using mass spectrometry. We first constructed a comprehensive 6mA landscape in sea buckthorn genome using nanopore sequencing at single-base resolution. Distribution analysis suggested that 6mA methylated sites were widely distributed in the sea buckthorn chromosomes, which were similar to those in Arabidopsis and rice. Furthermore, reduced 6mA DNA methylation is associated with different expression of genes related to the fruit-ripening process in sea buckthorn. Our results revealed that 6mA DNA modification could be considered an important epigenomic mark and contributes to the fruit ripening process in plants.
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Affiliation(s)
- Guoyun Zhang
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation, National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, xiangshan street, haidian district, China
| | - Songfeng Diao
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation, National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, xiangshan street, haidian district, China
| | - Yating Song
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation, National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, xiangshan street, haidian district, China
| | - Caiyun He
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation, National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, xiangshan street, haidian district, China
| | - Jianguo Zhang
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation, National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, xiangshan street, haidian district, China
- Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forestry University, longpan street, xuanwu district, China
- Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China
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27
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Chen J, Hu R, Chen Y, Lin X, Xiang W, Chen H, Yao C, Liu L. Structural basis for MTA1c-mediated DNA N6-adenine methylation. Nat Commun 2022; 13:3257. [PMID: 35672411 PMCID: PMC9174199 DOI: 10.1038/s41467-022-31060-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 05/26/2022] [Indexed: 11/09/2022] Open
Abstract
DNA N6-adenine methylation (6 mA) has recently been found to play a crucial role in epigenetic regulation in eukaryotes. MTA1c, a newly discovered 6 mA methyltransferase complex in ciliates, is composed of MTA1, MTA9, p1 and p2 subunits and specifically methylates ApT dinucleotides, yet its mechanism of action remains unknown. Here, we report the structures of Tetrahymena thermophila MTA1 (TthMTA1), Paramecium tetraurelia MTA9 (PteMTA9)-TthMTA1 binary complex, as well as the structures of TthMTA1-p1-p2 and TthMTA1-p2 complexes in apo, S-adenosyl methionine-bound and S-adenosyl homocysteine-bound states. We show that MTA1 is the catalytically active subunit, p1 and p2 are involved in the formation of substrate DNA-binding channel, and MTA9 plays a structural role in the stabilization of substrate binding. We identify that MTA1 is a cofactor-dependent catalytically active subunit, which exhibits stable SAM-binding activity only after assembly with p2. Our structures and corresponding functional studies provide a more detailed mechanistic understanding of 6 mA methylation.
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Affiliation(s)
- Jiyun Chen
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, 361102, Fujian, China
| | - Rong Hu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, 361102, Fujian, China
| | - Ying Chen
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, 361102, Fujian, China
| | - Xiaofeng Lin
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, 361102, Fujian, China
| | - Wenwen Xiang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, 361102, Fujian, China
| | - Hong Chen
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, 361102, Fujian, China
| | - Canglin Yao
- Department of Biological Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Liang Liu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, 361102, Fujian, China.
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28
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A fungal dioxygenase CcTet serves as a eukaryotic 6mA demethylase on duplex DNA. Nat Chem Biol 2022; 18:733-741. [PMID: 35654845 DOI: 10.1038/s41589-022-01041-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 03/31/2022] [Indexed: 12/24/2022]
Abstract
N6-methyladenosine (6mA) is a DNA modification that has recently been found to play regulatory roles during mammalian early embryo development and mitochondrial transcription. We found that a dioxygenase CcTet from the fungus Coprinopsis cinerea is also a dsDNA 6mA demethylase. It oxidizes 6mA to the intermediate N6-hydroxymethyladenosine (6hmA) with robust activity of 6mA-containing duplex DNA (dsDNA) as well as isolated genomics DNA. Structural characterization revealed that CcTet utilizes three flexible loop regions and two key residues-D337 and G331-in the active pocket to preferentially recognize substrates on dsDNA. A CcTet D337F mutant protein retained the catalytic activity on 6mA but lost activity on 5-methylcytosine. Our findings uncovered a 6mA demethylase that works on dsDNA, suggesting potential 6mA demethylation in fungi and elucidating 6mA recognition and the catalytic mechanism of CcTet. The CcTet D337F mutant protein also provides a chemical biology tool for future functional manipulation of DNA 6mA in vivo.
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29
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Li X, Guo S, Cui Y, Zhang Z, Luo X, Angelova MT, Landweber LF, Wang Y, Wu TP. NT-seq: a chemical-based sequencing method for genomic methylome profiling. Genome Biol 2022; 23:122. [PMID: 35637459 PMCID: PMC9150344 DOI: 10.1186/s13059-022-02689-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 05/16/2022] [Indexed: 12/15/2022] Open
Abstract
DNA methylation plays vital roles in both prokaryotes and eukaryotes. There are three forms of DNA methylation in prokaryotes: N6-methyladenine (6mA), N4-methylcytosine (4mC), and 5-methylcytosine (5mC). Although many sequencing methods have been developed to sequence specific types of methylation, few technologies can be used for efficiently mapping multiple types of methylation. Here, we present NT-seq for mapping all three types of methylation simultaneously. NT-seq reliably detects all known methylation motifs in two bacterial genomes and can be used for identifying de novo methylation motifs. NT-seq provides a simple and efficient solution for detecting multiple types of DNA methylation.
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Affiliation(s)
- Xuwen Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Shiyuan Guo
- Genetics, Genomics, and Bioinformatics Graduate Program, University of California Riverside, Riverside, CA, USA
| | - Yan Cui
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Zijian Zhang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Xinlong Luo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Margarita T Angelova
- Departments of Biochemistry and Molecular Biophysics and Biological Sciences, Columbia University, New York, NY, USA
| | - Laura F Landweber
- Departments of Biochemistry and Molecular Biophysics and Biological Sciences, Columbia University, New York, NY, USA
| | - Yinsheng Wang
- Genetics, Genomics, and Bioinformatics Graduate Program, University of California Riverside, Riverside, CA, USA.,Department of Chemistry, University of California Riverside, Riverside, CA, USA
| | - Tao P Wu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA. .,Huffington Center on Aging, Baylor College of Medicine, Houston, TX, USA. .,Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA.
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30
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Sheng Y, Zhou M, You C, Dai X. Dynamics and biological relevance of epigenetic N6-methyladenine DNA modification in eukaryotic cells. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2021.08.109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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31
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Boulias K, Greer EL. Means, mechanisms and consequences of adenine methylation in DNA. Nat Rev Genet 2022; 23:411-428. [PMID: 35256817 PMCID: PMC9354840 DOI: 10.1038/s41576-022-00456-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/31/2022] [Indexed: 12/29/2022]
Abstract
N6-methyl-2'-deoxyadenosine (6mA or m6dA) has been reported in the DNA of prokaryotes and eukaryotes ranging from unicellular protozoa and algae to multicellular plants and mammals. It has been proposed to modulate DNA structure and transcription, transmit information across generations and have a role in disease, among other functions. However, its existence in more recently evolved eukaryotes remains a topic of debate. Recent technological advancements have facilitated the identification and quantification of 6mA even when the modification is exceptionally rare, but each approach has limitations. Critical assessment of existing data, rigorous design of future studies and further development of methods will be required to confirm the presence and biological functions of 6mA in multicellular eukaryotes.
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O’Brown ZK, Greer EL. N6-methyladenine: A Rare and Dynamic DNA Mark. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1389:177-210. [DOI: 10.1007/978-3-031-11454-0_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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33
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Tellgren-Roth C, Couturier M. Detecting DNA Methylations in the Hyperthermoacidophilic Crenarchaeon Sulfolobus acidocaldarius Using SMRT Sequencing. Methods Mol Biol 2022; 2516:39-50. [PMID: 35922620 DOI: 10.1007/978-1-0716-2413-5_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
DNA methylations are one of the most well-known epigenetic modifications along with histone modifications and noncoding RNAs. They are found at specific sites along the DNA in all domains of life, with 5-mC and 6-mA/4-mC being well-characterized in eukaryotes and bacteria respectively, and they have not only been described as contributing to the structure of the double helix itself but also as regulators of DNA-based processes such as replication, transcription, and recombination. Different methods have been developed to accurately identify and/or map methylated motifs to decipher the involvement of DNA methylations in regulatory networks that affect the cellular state.Although DNA methylations have been detected along archaeal genomes, their involvement as regulators of DNA-based processes remains the least known. To highlight the importance of DNA methylations in the control of key cellular mechanisms and their dynamics in archaea cells, we have used single-molecule real-time (SMRT) sequencing. This sequencing technology allows the identification and direct mapping of the methylated motifs along the genome of an organism. In this chapter, we present a step-by-step protocol for detecting DNA methylations in the hyperthermophilic crenarchaeon Sulfolobus acidocaldarius using SMRT sequencing. This protocol can easily be adapted to other prokaryotes.
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Affiliation(s)
- Christian Tellgren-Roth
- Department of Immunology, Genetics and Pathology, National Genomics Infrastructure, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Mohea Couturier
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium.
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Recent Advances on DNA Base Flipping: A General Mechanism for Writing, Reading, and Erasing DNA Modifications. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1389:295-315. [DOI: 10.1007/978-3-031-11454-0_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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35
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DNA Methyltransferases and DNA Damage. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1389:349-361. [DOI: 10.1007/978-3-031-11454-0_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Luyten Y, Hausman DE, Young JC, Doyle L, Higashi K, Ubilla-Rodriguez N, Lambert AR, Arroyo CS, Forsberg K, Morgan R, Stoddard B, Kaiser B. OUP accepted manuscript. Nucleic Acids Res 2022; 50:5171-5190. [PMID: 35511079 PMCID: PMC9122589 DOI: 10.1093/nar/gkac311] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 04/13/2022] [Accepted: 04/19/2022] [Indexed: 11/16/2022] Open
Abstract
Bacteriophage exclusion (‘BREX’) phage restriction systems are found in a wide range of bacteria. Various BREX systems encode unique combinations of proteins that usually include a site-specific methyltransferase; none appear to contain a nuclease. Here we describe the identification and characterization of a Type I BREX system from Acinetobacter and the effect of deleting each BREX ORF on growth, methylation, and restriction. We identified a previously uncharacterized gene in the BREX operon that is dispensable for methylation but involved in restriction. Biochemical and crystallographic analyses of this factor, which we term BrxR (‘BREX Regulator’), demonstrate that it forms a homodimer and specifically binds a DNA target site upstream of its transcription start site. Deletion of the BrxR gene causes cell toxicity, reduces restriction, and significantly increases the expression of BrxC. In contrast, the introduction of a premature stop codon into the BrxR gene, or a point mutation blocking its DNA binding ability, has little effect on restriction, implying that the BrxR coding sequence and BrxR protein play independent functional roles. We speculate that elements within the BrxR coding sequence are involved in cis regulation of anti-phage activity, while the BrxR protein itself plays an additional regulatory role, perhaps during horizontal transfer.
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Affiliation(s)
- Yvette A Luyten
- New England Biolabs, 240 County Road, Ipswich, MA 01938, USA
| | - Deanna E Hausman
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA 98109, USA
| | - Juliana C Young
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA 98109, USA
| | - Lindsey A Doyle
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA 98109, USA
| | - Kerilyn M Higashi
- Department of Biology, Seattle University, 901 12th Avenue, Seattle, WA 98122, USA
| | - Natalia C Ubilla-Rodriguez
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA 98109, USA
| | - Abigail R Lambert
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA 98109, USA
| | - Corina S Arroyo
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA 98109, USA
| | - Kevin J Forsberg
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA 98109, USA
| | | | - Barry L Stoddard
- To whom correspondence should be addressed. Tel: +1 206 667 4031;
| | - Brett K Kaiser
- Correspondence may also be addressed to Brett K. Kaiser. Tel: +1 206 220 8266;
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Feng Y, Neme R, Beh LY, Chen X, Braun J, Lu MW, Landweber LF. Comparative genomics reveals insight into the evolutionary origin of massively scrambled genomes. eLife 2022; 11:82979. [PMID: 36421078 PMCID: PMC9797194 DOI: 10.7554/elife.82979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 11/03/2022] [Indexed: 11/25/2022] Open
Abstract
Ciliates are microbial eukaryotes that undergo extensive programmed genome rearrangement, a natural genome editing process that converts long germline chromosomes into smaller gene-rich somatic chromosomes. Three well-studied ciliates include Oxytricha trifallax, Tetrahymena thermophila, and Paramecium tetraurelia, but only the Oxytricha lineage has a massively scrambled genome, whose assembly during development requires hundreds of thousands of precisely programmed DNA joining events, representing the most complex genome dynamics of any known organism. Here we study the emergence of such complex genomes by examining the origin and evolution of discontinuous and scrambled genes in the Oxytricha lineage. This study compares six genomes from three species, the germline and somatic genomes for Euplotes woodruffi, Tetmemena sp., and the model ciliate O. trifallax. We sequenced, assembled, and annotated the germline and somatic genomes of E. woodruffi, which provides an outgroup, and the germline genome of Tetmemena sp. We find that the germline genome of Tetmemena is as massively scrambled and interrupted as Oxytricha's: 13.6% of its gene loci require programmed translocations and/or inversions, with some genes requiring hundreds of precise gene editing events during development. This study revealed that the earlier diverged spirotrich, E. woodruffi, also has a scrambled genome, but only roughly half as many loci (7.3%) are scrambled. Furthermore, its scrambled genes are less complex, together supporting the position of Euplotes as a possible evolutionary intermediate in this lineage, in the process of accumulating complex evolutionary genome rearrangements, all of which require extensive repair to assemble functional coding regions. Comparative analysis also reveals that scrambled loci are often associated with local duplications, supporting a gradual model for the origin of complex, scrambled genomes via many small events of DNA duplication and decay.
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Affiliation(s)
- Yi Feng
- Departments of Biochemistry and Molecular Biophysics and Biological Sciences, Columbia UniversityNew YorkUnited States
| | - Rafik Neme
- Departments of Biochemistry and Molecular Biophysics and Biological Sciences, Columbia UniversityNew YorkUnited States,Department of Chemistry and Biology, Universidad del NorteBarranquillaColombia
| | - Leslie Y Beh
- Departments of Biochemistry and Molecular Biophysics and Biological Sciences, Columbia UniversityNew YorkUnited States
| | - Xiao Chen
- Pacific BiosciencesMenlo ParkUnited States
| | - Jasper Braun
- Department of Mathematics and Statistics, University of South FloridaTampaUnited States
| | - Michael W Lu
- Departments of Biochemistry and Molecular Biophysics and Biological Sciences, Columbia UniversityNew YorkUnited States
| | - Laura F Landweber
- Departments of Biochemistry and Molecular Biophysics and Biological Sciences, Columbia UniversityNew YorkUnited States
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Li K, Li Z, Wu J, Gong Y, Guo L, Xie J. In Vitro Evaluation of DNA Damage Effect Markers toward Five Nitrogen Mustards Based on Liquid Chromatography-Tandem Mass Spectrometry. Chem Res Toxicol 2021; 35:99-110. [PMID: 34969250 DOI: 10.1021/acs.chemrestox.1c00346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Endogenous DNA lesions frequently occur due to internal effects such as oxidative stress, inflammation, endogenous alkylation, and epigenetic modifications. However, exposure to chemical toxicants from the environment, diet, or drugs can also induce significant endogenous DNA damage. The quantification of endogenous DNA damage effect markers might reflect the actual DNA damage level of chemical toxicants. Herein, we report a liquid chromatography-triple quadrupole tandem mass spectrometry (LC-QqQ MS/MS) method for simultaneous determination of eight representative endogenous DNA damage biomarkers, including five endogenous DNA damage effect markers (oxidative damage, 8-oxo-dG; lipid peroxidation, εdA and N2-Et-dG; inflammation, 5-Cl-dC; and endogenous alkylation, O6-Me-dG), and three epigenetic modifications (5-m-dC, 5-hm-dC, and N6-Me-dA). The method validation was performed, and the linear range was 0.05 pg to 2 ng (on-column), the limit of detection was 0.02 pg (on-column), and the precision, accuracy, matrix effect, and recovery were all between 85 and 115%. We then applied this method to evaluate endogenous DNA damage to human embryonic lung fibroblast cells exposed to five nitrogen mustards [NMs, i.e., HN1, HN2, HN3, chlorambucil (CB), and cyclophosphamide (CTX)], where curcumin exposure was used as a control due to its inability to induce the formation of endogenous DNA adducts. The amounts of eight DNA adducts in the low-, middle-, and high-concentration exposure groups of five NMs were almost all significantly different from those in the blank group (P < 0.05). We obtained a positive correlation between the contents of eight DNA damage biomarkers and the inhibition dose of five NMs, except for N2-Et-dG and 5-Cl-dC. Via further principal component analysis and partial least squares discriminant analysis, we clustered all NMs into three units with different cytotoxicity levels, that is, HN2 and HN1 (highly toxic), HN3 and CB (moderately toxic), and CTX (less toxic). Moreover, for the same concentration of HN1/2/3 exposure groups, as the cytotoxicity increased according to the order of HN3 < HN1 < HN2, the contents of 8-oxo-dG, 5-m-dC, 5-hm-dC, and N6-Me-dA increased, whereas the content of O6-Me-dG decreased. Therefore, the contents of these DNA damage effect markers were somewhat related to the cytotoxicity and concentration of NMs. We hope that this method will provide an alternative evaluation approach for the toxicological effects of NMs and the safety of the medication.
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Affiliation(s)
- Kexin Li
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Haidian District, 100850 Beijing, China
| | - Zehua Li
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Haidian District, 100850 Beijing, China
| | - Jianfeng Wu
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Haidian District, 100850 Beijing, China
| | - Ying Gong
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Haidian District, 100850 Beijing, China
| | - Lei Guo
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Haidian District, 100850 Beijing, China
| | - Jianwei Xie
- State Key Laboratory of Toxicology and Medical Countermeasures, and Laboratory of Toxicant Analysis, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Haidian District, 100850 Beijing, China
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Guo C, Hu Y, Cao X, Wang Y. HILIC-MS/MS for the Determination of Methylated Adenine Nucleosides in Human Urine. Anal Chem 2021; 93:17060-17068. [PMID: 34902250 PMCID: PMC8751233 DOI: 10.1021/acs.analchem.1c03829] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
N6-methyl-2'-deoxyadenosine (m6dA) is a newly discovered DNA epigenetic mark in mammals. N6-methyladenosine (m6A), 2'-O-methyladenosine (Am), N6,2'-O-dimethyladenosine (m6Am), and N6,N6-dimethyladenosine (m62A) are common RNA modifications. Previous studies illustrated the associations between the aberrations of these methylated adenosines in nucleic acids and cancer. Herein, we developed Fe3O4/graphene-based magnetic dispersive solid-phase extraction for the enrichment and hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS/MS) for the measurements of m6dA, m6A, Am, m6Am, and m62A in human urine samples. We found that malic acid could improve the HILIC-based separation of these modified nucleosides and markedly enhance the sensitivity of their MS detection. With this method, we accurately quantified the contents of these modified adenine nucleosides in urine samples collected from gastric and colorectal cancer patients as well as healthy controls. We found that, relative to healthy controls, urinary m6dA and Am levels are significantly lower for gastric and colorectal cancer patients; while gastric cancer patients also exhibited lower levels of urinary m6A, the trend was opposite for colorectal cancer patients. Together, we developed a robust analytical method for simultaneous measurements of five methylated adenine nucleosides in human urine, and our results revealed an association between the levels of urinary methylated adenine nucleosides and the occurrence of gastric as well as colorectal cancers, suggesting the potential applications of these modified nucleosides as biomarkers for the early detection of these cancers.
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Affiliation(s)
- Cheng Guo
- Cancer Institute (Key Laboratory of Cancer Prevention and Intervention, Ministry of Education), The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China
| | - Yiqiu Hu
- Cancer Institute (Key Laboratory of Cancer Prevention and Intervention, Ministry of Education), The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China
| | - Xiaoji Cao
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China
| | - Yinsheng Wang
- Department of Chemistry, University of California, Riverside, California 92521, United States
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40
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DNA Methylation on N6-Adenine Regulates the Hyphal Development during Dimorphism in the Early-Diverging Fungus Mucor lusitanicus. J Fungi (Basel) 2021; 7:jof7090738. [PMID: 34575776 PMCID: PMC8470550 DOI: 10.3390/jof7090738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 09/03/2021] [Accepted: 09/06/2021] [Indexed: 12/14/2022] Open
Abstract
The epigenetic modifications control the pathogenicity of human pathogenic fungi, which have been poorly studied in Mucorales, causative agents of mucormycosis. This order belongs to a group referred to as early-diverging fungi that are characterized by high levels of N6-methyldeoxy adenine (6mA) in their genome with dense 6mA clusters associated with actively expressed genes. AlkB enzymes can act as demethylases of 6mA in DNA, with the most remarkable eukaryotic examples being mammalian ALKBH1 and Caenorhabditis elegans NMAD-1. The Mucor lusitanicus (formerly M. circinelloides f. lusitanicus) genome contains one gene, dmt1, and two genes, dmt2 and dmt3, encoding proteins similar to C. elegans NMAD-1 and ALKBH1, respectively. The function of these three genes was analyzed by the generation of single and double deletion mutants for each gene. Multiple processes were studied in the mutants, but defects were only found in single and double deletion mutants for dmt1. In contrast to the wild-type strain, dmt1 mutants showed an increase in 6mA levels during the dimorphic transition, suggesting that 6mA is associated with dimorphism in M. lusitanicus. Furthermore, the spores of dmt1 mutants challenged with macrophages underwent a reduction in polar growth, suggesting that 6mA also has a role during the spore–macrophage interaction that could be important in the infection process.
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41
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Li X, Zhang Z, Luo X, Schrier J, Yang AD, Wu TP. The exploration of N6-deoxyadenosine methylation in mammalian genomes. Protein Cell 2021; 12:756-768. [PMID: 34405377 PMCID: PMC8464638 DOI: 10.1007/s13238-021-00866-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 07/12/2021] [Indexed: 11/11/2022] Open
Abstract
N6-methyladenine (N6-mA, m6dA, or 6mA), a prevalent DNA modification in prokaryotes, has recently been identified in higher eukaryotes, including mammals. Although 6mA has been well-studied in prokaryotes, the function and regulatory mechanism of 6mA in eukaryotes are still poorly understood. Recent studies indicate that 6mA can serve as an epigenetic mark and play critical roles in various biological processes, from transposable-element suppression to environmental stress response. Here, we review the significant advances in methodology for 6mA detection and major progress in understanding the regulation and function of this non-canonical DNA methylation in eukaryotes, predominantly mammals.
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Affiliation(s)
- Xuwen Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Zijian Zhang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Xinlong Luo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jacob Schrier
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Andrew D Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.,Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Tao P Wu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA. .,Huffington Center on Aging, Baylor College of Medicine, Houston, TX, 77030, USA. .,Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, 77030, USA.
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42
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Faillace MP, Bernabeu RO. Epigenetic Mechanisms Mediate Nicotine-Induced Reward and Behaviour in Zebrafish. Curr Neuropharmacol 2021; 20:510-523. [PMID: 34279203 PMCID: PMC9608226 DOI: 10.2174/1570159x19666210716112351] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 06/03/2021] [Accepted: 07/11/2021] [Indexed: 11/26/2022] Open
Abstract
Nicotine induces long-term changes in the neural activity of the mesocorticolimbic reward pathway structures. The mechanisms involved in this process have not been fully characterized. The hypothesis discussed here proposed that epigenetic regulation participates in the installation of persistent adaptations and long-lasting synaptic plasticity generated by nicotine action on the mesolimbic dopamine neurons of zebrafish. The epigenetic mechanisms induced by nicotine entail histone and DNA chemical modifications, which have been described to lead to changes in gene expression. Among the enzymes that catalyze epigenetic chemical modifications, histone deacetylases (HDACs) remove acetyl groups from histones, thereby facilitating DNA relaxation and making DNA more accessible to gene transcription. DNA methylation, which is dependent on DNA methyltransferase (DNMTs) activity, inhibits gene expression by recruiting several methyl binding proteins that prevent RNA polymerase binding to DNA. In zebrafish, phenylbutyrate (PhB), an HDAC inhibitor, abolishes nicotine rewarding properties together with a series of typical reward-associated behaviors. Furthermore, PhB and nicotine alter long- and short-term object recognition memory in zebrafish, respectively. Regarding DNA methylation effects, a methyl group donor L-methionine (L-met) was found to dramatically reduce nicotine-induced conditioned place preference (CPP) in zebrafish. Simultaneous treatment with DNMT inhibitor 5-aza-2’-deoxycytidine (AZA) was found to reverse the L-met effect on nicotine-induced CPP as well as nicotine reward-specific effects on genetic expression in zebrafish. Therefore, pharmacological interventions that modulate epigenetic regulation of gene expression should be considered as a potential therapeutic method to treat nicotine addiction.
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Affiliation(s)
- Maria Paula Faillace
- Departamento de Fisiología, Facultad de Medicina e Instituto de Fisiología y Biofísica Profesor Bernardo Houssay (IFIBIO-Houssay, CONICET-UBA), Universidad de Buenos Aires (UBA), Ciudad Autónoma de Buenos Aires, Argentina
| | - Ramón O Bernabeu
- Departamento de Fisiología, Facultad de Medicina e Instituto de Fisiología y Biofísica Profesor Bernardo Houssay (IFIBIO-Houssay, CONICET-UBA), Universidad de Buenos Aires (UBA), Ciudad Autónoma de Buenos Aires, Argentina
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Abstract
The field of epigenetics has exploded over the last two decades, revealing an astonishing level of complexity in the way genetic information is stored and accessed in eukaryotes. This expansion of knowledge, which is very much ongoing, has been made possible by the availability of evermore sensitive and precise molecular tools. This review focuses on the increasingly important role that chemistry plays in this burgeoning field. In an effort to make these contributions more accessible to the nonspecialist, we group available chemical approaches into those that allow the covalent structure of the protein and DNA components of chromatin to be manipulated, those that allow the activity of myriad factors that act on chromatin to be controlled, and those that allow the covalent structure and folding of chromatin to be characterized. The application of these tools is illustrated through a series of case studies that highlight how the molecular precision afforded by chemistry is being used to establish causal biochemical relationships at the heart of epigenetic regulation.
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Affiliation(s)
- John D Bagert
- Frick Chemistry Laboratory, Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA; ,
| | - Tom W Muir
- Frick Chemistry Laboratory, Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA; ,
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Case Study of the Response of N 6-Methyladenine DNA Modification to Environmental Stressors in the Unicellular Eukaryote Tetrahymena thermophila. mSphere 2021; 6:e0120820. [PMID: 34047647 PMCID: PMC8265677 DOI: 10.1128/msphere.01208-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Rediscovered as a potential epigenetic mark, N6-methyladenine DNA modification (6mA) was recently reported to be sensitive to environmental stressors in several multicellular eukaryotes. As 6mA distribution and function differ significantly in multicellular and unicellular organisms, whether and how 6mA in unicellular eukaryotes responds to environmental stress remains elusive. Here, we characterized the dynamic changes of 6mA under starvation in the unicellular model organism Tetrahymena thermophila. Single-molecule, real-time (SMRT) sequencing reveals that DNA 6mA levels in starved cells are significantly reduced, especially symmetric 6mA, compared to those in vegetatively growing cells. Despite a global 6mA reduction, the fraction of asymmetric 6mA with a high methylation level was increased, which might be the driving force for stronger nucleosome positioning in starved cells. Starvation affects expression of many metabolism-related genes, the expression level change of which is associated with the amount of 6mA change, thereby linking 6mA with global transcription and starvation adaptation. The reduction of symmetric 6mA and the increase of asymmetric 6mA coincide with the downregulation of AMT1 and upregulation of AMT2 and AMT5, which are supposedly the MT-A70 methyltransferases required for symmetric and asymmetric 6mA, respectively. These results demonstrated that a regulated 6mA response to environmental cues is evolutionarily conserved in eukaryotes. IMPORTANCE Increasing evidence indicated that 6mA could respond to environmental stressors in multicellular eukaryotes. As 6mA distribution and function differ significantly in multicellular and unicellular organisms, whether and how 6mA in unicellular eukaryotes responds to environmental stress remains elusive. In the present work, we characterized the dynamic changes of 6mA under starvation in the unicellular model organism Tetrahymena thermophila. Our results provide insights into how Tetrahymena fine-tunes its 6mA level and composition upon starvation, suggesting that a regulated 6mA response to environmental cues is evolutionarily conserved in eukaryotes.
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Biodiversity-based development and evolution: the emerging research systems in model and non-model organisms. SCIENCE CHINA-LIFE SCIENCES 2021; 64:1236-1280. [PMID: 33893979 DOI: 10.1007/s11427-020-1915-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 03/16/2021] [Indexed: 02/07/2023]
Abstract
Evolutionary developmental biology, or Evo-Devo for short, has become an established field that, broadly speaking, seeks to understand how changes in development drive major transitions and innovation in organismal evolution. It does so via integrating the principles and methods of many subdisciplines of biology. Although we have gained unprecedented knowledge from the studies on model organisms in the past decades, many fundamental and crucially essential processes remain a mystery. Considering the tremendous biodiversity of our planet, the current model organisms seem insufficient for us to understand the evolutionary and physiological processes of life and its adaptation to exterior environments. The currently increasing genomic data and the recently available gene-editing tools make it possible to extend our studies to non-model organisms. In this review, we review the recent work on the regulatory signaling of developmental and regeneration processes, environmental adaptation, and evolutionary mechanisms using both the existing model animals such as zebrafish and Drosophila, and the emerging nonstandard model organisms including amphioxus, ascidian, ciliates, single-celled phytoplankton, and marine nematode. In addition, the challenging questions and new directions in these systems are outlined as well.
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46
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Cheng M, Shu X, Cao J, Gao M, Xiang S, Wang F, Wang Y, Liu J. A Mutation-Based Method for Pinpointing a DNA N 6 -Methyladenine Methyltransferase Modification Site at Single Base Resolution. Chembiochem 2021; 22:1936-1939. [PMID: 33779011 DOI: 10.1002/cbic.202100088] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/26/2021] [Indexed: 01/01/2023]
Abstract
DNA N6 -methyladenine (6mA) has recently received notable attention due to an increased finding of its functional roles in higher eukaryotes. Here we report an enzyme-assisted chemical labeling method to pinpoint the DNA 6mA methyltransferase (MTase) substrate modification site at single base resolution. A designed allyl-substituted MTase cofactor was applied in the catalytic transfer reaction, and the allyl group was installed to the N6 -position of adenine within a specific DNA sequence to form N6 -allyladenine (6aA). The iodination of 6aA allyl group induced the formation of 1, N6 -cyclized adenine which caused mutations during DNA replication by a polymerase. Thus the modification site could be precisely detected by a mutation signal. We synthesized 6aA deoxynucleoside and deoxynucleotide model compounds and a 6aA-containing DNA probe, and screened nine DNA polymerases to define an optimal system capable of detecting the substrate modification site of a DNA 6mA MTase at single-base resolution.
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Affiliation(s)
- Mohan Cheng
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Zheda Road 38, Hangzhou, 310027, China
| | - Xiao Shu
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Zheda Road 38, Hangzhou, 310027, China
| | - Jie Cao
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Zheda Road 38, Hangzhou, 310027, China
| | - Minsong Gao
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Zheda Road 38, Hangzhou, 310027, China
| | - Siying Xiang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Zheda Road 38, Hangzhou, 310027, China
| | - Fengqin Wang
- College of Animal Sciences, Key Laboratory of Animal Nutrition and Feed Sciences, Ministry of Agriculture, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, China
| | - Yizhen Wang
- College of Animal Sciences, Key Laboratory of Animal Nutrition and Feed Sciences, Ministry of Agriculture, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, China
| | - Jianzhao Liu
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Zheda Road 38, Hangzhou, 310027, China
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47
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Miller RV, Neme R, Clay DM, Pathmanathan JS, Lu MW, Yerlici VT, Khurana JS, Landweber LF. Transcribed germline-limited coding sequences in Oxytricha trifallax. G3-GENES GENOMES GENETICS 2021; 11:6192809. [PMID: 33772542 PMCID: PMC8495736 DOI: 10.1093/g3journal/jkab092] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 02/26/2021] [Indexed: 01/13/2023]
Abstract
The germline-soma divide is a fundamental distinction in developmental biology, and different genes are expressed in germline and somatic cells throughout metazoan life cycles. Ciliates, a group of microbial eukaryotes, exhibit germline-somatic nuclear dimorphism within a single cell with two different genomes. The ciliate Oxytricha trifallax undergoes massive RNA-guided DNA elimination and genome rearrangement to produce a new somatic macronucleus (MAC) from a copy of the germline micronucleus (MIC). This process eliminates noncoding DNA sequences that interrupt genes and also deletes hundreds of germline-limited open reading frames (ORFs) that are transcribed during genome rearrangement. Here, we update the set of transcribed germline-limited ORFs (TGLOs) in O. trifallax. We show that TGLOs tend to be expressed during nuclear development and then are absent from the somatic MAC. We also demonstrate that exposure to synthetic RNA can reprogram TGLO retention in the somatic MAC and that TGLO retention leads to transcription outside the normal developmental program. These data suggest that TGLOs represent a group of developmentally regulated protein-coding sequences whose gene expression is terminated by DNA elimination.
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Affiliation(s)
- Richard V Miller
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.,Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Rafik Neme
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Derek M Clay
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.,Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Jananan S Pathmanathan
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Michael W Lu
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.,Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - V Talya Yerlici
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Jaspreet S Khurana
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Laura F Landweber
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.,Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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48
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Nucleosome Positioning and Spacing: From Mechanism to Function. J Mol Biol 2021; 433:166847. [PMID: 33539878 DOI: 10.1016/j.jmb.2021.166847] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 01/16/2021] [Accepted: 01/22/2021] [Indexed: 02/08/2023]
Abstract
Eukaryotes associate their genomes with histone proteins, forming nucleosome particles. Nucleosomes regulate and protect the genetic information. They often assemble into evenly spaced arrays of nucleosomes. These regular nucleosome arrays cover significant portions of the genome, in particular over genes. The presence of these evenly spaced nucleosome arrays is highly conserved throughout the entire eukaryotic domain. Here, we review the mechanisms behind the establishment of this primary structure of chromatin with special emphasis on the biogenesis of evenly spaced nucleosome arrays. We highlight the roles that transcription, nucleosome remodelers, DNA sequence, and histone density play towards the formation of evenly spaced nucleosome arrays and summarize our current understanding of their cellular functions. We end with key unanswered questions that remain to be explored to obtain an in-depth understanding of the biogenesis and function of the nucleosome landscape.
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49
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The Compact Macronuclear Genome of the Ciliate Halteria grandinella: A Transcriptome-Like Genome with 23,000 Nanochromosomes. mBio 2021; 12:mBio.01964-20. [PMID: 33500338 PMCID: PMC7858049 DOI: 10.1128/mbio.01964-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
How to achieve protein diversity by genome and transcriptome processing is essential for organismal complexity and adaptation. The present work identifies that the macronuclear genome of Halteria grandinella, a cosmopolitan unicellular eukaryote, is composed almost entirely of gene-sized nanochromosomes with extremely short nongenic regions. How to achieve protein diversity by genome and transcriptome processing is essential for organismal complexity and adaptation. The present work identifies that the macronuclear genome of Halteria grandinella, a cosmopolitan unicellular eukaryote, is composed almost entirely of gene-sized nanochromosomes with extremely short nongenic regions. This challenges our usual understanding of chromosomal structure and suggests the possibility of novel mechvanisms in transcriptional regulation. Comprehensive analysis of multiple data sets reveals that Halteria transcription dynamics are influenced by: (i) nonuniform nanochromosome copy numbers correlated with gene-expression level; (ii) dynamic alterations at both the DNA and RNA levels, including alternative internal eliminated sequence (IES) deletions during macronucleus formation and large-scale alternative splicing in transcript maturation; and (iii) extremely short 5′ and 3′ untranslated regions (UTRs) and universal TATA box-like motifs in the compact 5′ subtelomeric regions of most chromosomes. This study broadens the view of ciliate biology and the evolution of unicellular eukaryotes, and identifies Halteria as one of the most compact known eukaryotic genomes, indicating that complex cell structure does not require complex gene architecture.
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50
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Hardy A, Matelot M, Touzeau A, Klopp C, Lopez-Roques C, Duharcourt S, Defrance M. DNAModAnnot: a R toolbox for DNA modification filtering and annotation. Bioinformatics 2021; 37:2738-2740. [PMID: 33471071 PMCID: PMC8428616 DOI: 10.1093/bioinformatics/btab032] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 12/17/2020] [Accepted: 01/13/2021] [Indexed: 11/13/2022] Open
Abstract
MOTIVATION Long-read sequencing technologies can be employed to detect and map DNA modifications at the nucleotide resolution on a genome-wide scale. However, published software packages neglect the integration of genomic annotation and comprehensive filtering when analyzing patterns of modified bases detected using Pacific Biosciences (PacBio) or Oxford Nanopore Technologies (ONT) data. Here, we present DNAModAnnot, a R package designed for the global analysis of DNA modification patterns using adapted filtering and visualization tools. RESULTS We tested our package using PacBio sequencing data to analyze patterns of the 6-methyladenine (6 mA) in the ciliate Paramecium tetraurelia, in which high 6 mA amounts were previously reported. We found Paramecium tetraurelia 6 mA genome-wide distribution to be similar to other ciliates. We also performed 5-methylcytosine (5mC) analysis in human lymphoblastoid cells using ONT data and confirmed previously known patterns of 5mC. DNAModAnnot provides a toolbox for the genome-wide analysis of different DNA modifications using PacBio and ONT long-read sequencing data. AVAILABILITY DNAModAnnot is distributed as a R package available via GitHub (https://github.com/AlexisHardy/DNAModAnnot). SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Alexis Hardy
- Université de Paris, CNRS, Institut Jacques Monod, F-75006, Paris, France
| | - Mélody Matelot
- Université de Paris, CNRS, Institut Jacques Monod, F-75006, Paris, France
| | - Amandine Touzeau
- Université de Paris, CNRS, Institut Jacques Monod, F-75006, Paris, France
| | - Christophe Klopp
- Plateforme bioinformatique Genotoul, UR875 Mathématique et Informatique Appliquée de Toulouse, INRA, 31326, Castanet-Tolosan, France
| | | | - Sandra Duharcourt
- Université de Paris, CNRS, Institut Jacques Monod, F-75006, Paris, France
| | - Matthieu Defrance
- Université Libre de Bruxelles, Interuniversity Institute of Bioinformatics in Brussels (IB2), Brussels, 1050, Belgium
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