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Seah BKB, Singh A, Vetter DE, Emmerich C, Peters M, Soltys V, Huettel B, Swart EC. Nuclear dualism without extensive DNA elimination in the ciliate Loxodes magnus. Proc Natl Acad Sci U S A 2024; 121:e2400503121. [PMID: 39298487 DOI: 10.1073/pnas.2400503121] [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: 01/17/2024] [Accepted: 08/08/2024] [Indexed: 09/21/2024] Open
Abstract
Most eukaryotes have one nucleus and nuclear genome per cell. Ciliates have instead evolved distinct nuclei that coexist in each cell: a silent germline vs. transcriptionally active somatic nuclei. In the best-studied model species, both nuclei can divide asexually, but only germline nuclei undergo meiosis and karyogamy during sex. Thereafter, thousands of DNA segments, called internally eliminated sequences (IESs), are excised from copies of the germline genomes to produce the streamlined somatic genome. In Loxodes, however, somatic nuclei cannot divide but instead develop from germline copies even during asexual cell division, which would incur a huge overhead cost if genome editing was required. Here, we purified and sequenced both genomes in Loxodes magnus to see whether their nondividing somatic nuclei are associated with differences in genome architecture. Unlike in other ciliates studied to date, we did not find canonical germline-limited IESs, implying Loxodes does not extensively edit its genomes. Instead, both genomes appear large and equivalent, replete with retrotransposons and repetitive sequences, unlike the compact, gene-rich somatic genomes of other ciliates. Two other hallmarks of nuclear development in ciliates-domesticated DDE-family transposases and editing-associated small RNAs-were also not found. Thus, among the ciliates, Loxodes genomes most resemble those of conventional eukaryotes. Nonetheless, base modifications, histone marks, and nucleosome positioning of vegetative Loxodes nuclei are consistent with functional differentiation between actively transcribed somatic vs. inactive germline nuclei. Given their phylogenetic position, it is likely that editing was present in the ancestral ciliate but secondarily lost in the Loxodes lineage.
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Affiliation(s)
- Brandon K B Seah
- Max Planck Institute for Biology, Tübingen 72076, Germany
- Thünen Institute for Biodiversity, Braunschweig 38116, Germany
| | - Aditi Singh
- Max Planck Institute for Biology, Tübingen 72076, Germany
| | - David E Vetter
- Max Planck Institute for Biology, Tübingen 72076, Germany
- Faculty of Science, Eberhard Karls Universität Tübingen, Tübingen 72076, Germany
| | | | - Moritz Peters
- Max Planck Institute for Biology, Tübingen 72076, Germany
- Friedrich Miescher Laboratory, Tübingen 72076, Germany
| | - Volker Soltys
- Max Planck Institute for Biology, Tübingen 72076, Germany
- Friedrich Miescher Laboratory, Tübingen 72076, Germany
| | - Bruno Huettel
- Max Planck Genome Centre Cologne, Max Planck Institute for Plant Breeding Research, Cologne 50829, Germany
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Liang Z, Chen S, Li Y, Lai W, Wang H. Adenosine Deaminase-Like Gene-Carried Lentivirus Toolkit for Identification of DNA N 6-Methyladenine Origins. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2403376. [PMID: 39023073 PMCID: PMC11425204 DOI: 10.1002/advs.202403376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 06/25/2024] [Indexed: 07/20/2024]
Abstract
Post-replicative DNA N6-methyladenine (pr6mdA) can form via bona fide methylase-catalyzed adenine methylation, playing a pivotal role in embryonic development and other biological processes. Surprisingly, pre-methylated adenine can be erroneously incorporated into DNA as misincorporated N6-methyladenine (i6mdA) via DNA polymerase-mediated replication. Despite pr6mdA and i6mdA sharing identical chemical structures, their biological functions diverge significantly, presenting a substantial challenge in distinguishing between the two. Here, for the first-time, it is exploited that the adenosine deaminase-like (Adal) protein and a corresponding activity-null mutant to construct an Adal lentivirus toolkit. With this newly designed toolkit, both pr6mdA and i6mdA can be identified and quantified simultaneously. The presence of 6mdA in the bone marrow cells of mice is shown, with its levels serving as indicators for growth with age, probably reflecting the cellular stress-caused changes in RNA decay, nucleotide pool sanitation, and transcription. Collectively, a powerful toolkit to advance understanding of both pr6mdA and i6mdA is demonstrated.
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Affiliation(s)
- Ziyu Liang
- The State Key Laboratory of Environmental Chemistry and EcotoxicologyResearch Center for Eco‐Environmental SciencesChinese Academy of SciencesBeijing10085P. R. China
- University of Chinese Academy of SciencesBeijing100049P. R. China
| | - Shaokun Chen
- The State Key Laboratory of Environmental Chemistry and EcotoxicologyResearch Center for Eco‐Environmental SciencesChinese Academy of SciencesBeijing10085P. R. China
| | - Yao Li
- The State Key Laboratory of Environmental Chemistry and EcotoxicologyResearch Center for Eco‐Environmental SciencesChinese Academy of SciencesBeijing10085P. R. China
- University of Chinese Academy of SciencesBeijing100049P. R. China
| | - Weiyi Lai
- The State Key Laboratory of Environmental Chemistry and EcotoxicologyResearch Center for Eco‐Environmental SciencesChinese Academy of SciencesBeijing10085P. R. China
| | - Hailin Wang
- The State Key Laboratory of Environmental Chemistry and EcotoxicologyResearch Center for Eco‐Environmental SciencesChinese Academy of SciencesBeijing10085P. R. China
- University of Chinese Academy of SciencesBeijing100049P. R. China
- School of Environment and HealthJianghan UniversityWuhan430056China
- Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou310024China
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3
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Tian K, Liu C, Cai Y, Zhou C. Role of 6mA in the Regulation of Metabolic Biosynthesis in Sorghum Callus. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:19232-19245. [PMID: 39138187 DOI: 10.1021/acs.jafc.4c03411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
Plant cell culture technology helps to obtain natural plant-derived metabolites. The callus of sorghum, a prominent cereal crop, possesses various metabolites with potential health benefits. However, the epigenetic mechanism regulating metabolic biosynthetic capabilities in sorghum remains unknown. Therefore, we conducted N6-methyladenine (6mA) methylome analysis using transcriptome profiling and metabolome analysis to investigate the role of 6mA alterations in two calluses having different biosynthetic capacities, which were derived from immature sorghum embryos. Our findings indicate that the 6mA upregulation within gene bodies is crucial in transcriptional activity potentially mediated by the DNA demethylase SbALKBH1. Furthermore, 6mA was significantly enriched in genes involved in the biosynthesis of flavonoids and isoflavonoids. This could serve as a novel source of bioactive compounds for human health. Thus, 6mA could play an essential role in flavonoid biosynthesis in the sorghum callus.
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Affiliation(s)
- Kewei Tian
- Key Laboratory of Three Gorges Regional Plant Genetics and Germplasm Enhancement (CTGU)/Biotechnology Research Center, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang 443002, China
| | - Chang Liu
- Key Laboratory of Three Gorges Regional Plant Genetics and Germplasm Enhancement (CTGU)/Biotechnology Research Center, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang 443002, China
| | - Yanjun Cai
- Key Laboratory of Three Gorges Regional Plant Genetics and Germplasm Enhancement (CTGU)/Biotechnology Research Center, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang 443002, China
| | - Chao Zhou
- Key Laboratory of Three Gorges Regional Plant Genetics and Germplasm Enhancement (CTGU)/Biotechnology Research Center, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang 443002, China
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4
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Hahn A, Hung GCC, Ahier A, Dai CY, Kirmes I, Forde BM, Campbell D, Lee RSY, Sucic J, Onraet T, Zuryn S. Misregulation of mitochondrial 6mA promotes the propagation of mutant mtDNA and causes aging in C. elegans. Cell Metab 2024:S1550-4131(24)00291-2. [PMID: 39173633 DOI: 10.1016/j.cmet.2024.07.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 03/21/2024] [Accepted: 07/26/2024] [Indexed: 08/24/2024]
Abstract
In virtually all eukaryotes, the mitochondrial DNA (mtDNA) encodes proteins necessary for oxidative phosphorylation (OXPHOS) and RNAs required for their synthesis. The mechanisms of regulation of mtDNA copy number and expression are not completely understood but crucially ensure the correct stoichiometric assembly of OXPHOS complexes from nuclear- and mtDNA-encoded subunits. Here, we detect adenosine N6-methylation (6mA) on the mtDNA of diverse animal and plant species. This modification is regulated in C. elegans by the DNA methyltransferase DAMT-1 and demethylase ALKB-1. Misregulation of mtDNA 6mA through targeted modulation of these activities inappropriately alters mtDNA copy number and transcript levels, impairing OXPHOS function, elevating oxidative stress, and shortening lifespan. Compounding these defects, mtDNA 6mA hypomethylation promotes the cross-generational propagation of a deleterious mtDNA. Together, these results reveal that mtDNA 6mA is highly conserved among eukaryotes and regulates lifespan by influencing mtDNA copy number, expression, and heritable mutation levels in vivo.
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Affiliation(s)
- Anne Hahn
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Grace Ching Ching Hung
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Arnaud Ahier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Chuan-Yang Dai
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Ina Kirmes
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Brian M Forde
- UQ Centre for Clinical Research, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Daniel Campbell
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Rachel Shin Yie Lee
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Josiah Sucic
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Tessa Onraet
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Steven Zuryn
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
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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 PMCID: PMC11216311 DOI: 10.1101/gr.277843.123] [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: 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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Geens B, Goossens S, Li J, Van de Peer Y, Vanden Broeck J. Untangling the gordian knot: The intertwining interactions between developmental hormone signaling and epigenetic mechanisms in insects. Mol Cell Endocrinol 2024; 585:112178. [PMID: 38342134 DOI: 10.1016/j.mce.2024.112178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/30/2024] [Accepted: 02/04/2024] [Indexed: 02/13/2024]
Abstract
Hormones control developmental and physiological processes, often by regulating the expression of multiple genes simultaneously or sequentially. Crosstalk between hormones and epigenetics is pivotal to dynamically coordinate this process. Hormonal signals can guide the addition and removal of epigenetic marks, steering gene expression. Conversely, DNA methylation, histone modifications and non-coding RNAs can modulate regional chromatin structure and accessibility and regulate the expression of numerous (hormone-related) genes. Here, we provide a review of the interplay between the classical insect hormones, ecdysteroids and juvenile hormones, and epigenetics. We summarize the mode-of-action and roles of these hormones in post-embryonic development, and provide a general overview of epigenetic mechanisms. We then highlight recent advances on the interactions between these hormonal pathways and epigenetics, and their involvement in development. Furthermore, we give an overview of several 'omics techniques employed in the field. Finally, we discuss which questions remain unanswered and possible avenues for future research.
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Affiliation(s)
- Bart Geens
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59 box 2465, B-3000 Leuven, Belgium.
| | - Stijn Goossens
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59 box 2465, B-3000 Leuven, Belgium.
| | - Jia Li
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium; VIB Center for Plant Systems Biology, VIB, Ghent, Belgium.
| | - Yves Van de Peer
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium; VIB Center for Plant Systems Biology, VIB, Ghent, Belgium.
| | - Jozef Vanden Broeck
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59 box 2465, B-3000 Leuven, Belgium.
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Fang S, Wang H, Qiu K, Pang Y, Li C, Liang X. The fungicide pyraclostrobin affects gene expression by altering the DNA methylation pattern in Magnaporthe oryzae. FRONTIERS IN PLANT SCIENCE 2024; 15:1391900. [PMID: 38745924 PMCID: PMC11091397 DOI: 10.3389/fpls.2024.1391900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/17/2024] [Indexed: 05/16/2024]
Abstract
Introduction Rice blast disease caused by Magnaporthe oryzae has long been the main cause of rice (Oryza sativa L.) yield reduction worldwide. The quinone external inhibitor pyraclostrobin is widely used as a fungicide to effectively control the spread of pathogenic fungi, including M. oryzae. However, M. oryzae can develop resistance through multiple levels of mutation, such as target protein cytb mutation G143A/S, leading to a decrease in the effectiveness of the biocide after a period of application. Therefore, uncovering the possible mutational mechanisms from multiple perspectives will further provide feasible targets for drug development. Methods In this work, we determined the gene expression changes in M. oryzae in response to pyraclostrobin stress and their relationship with DNA methylation by transcriptome and methylome. Results The results showed that under pyraclostrobin treatment, endoplasmic reticulum (ER)-associated and ubiquitin-mediated proteolysis were enhanced, suggesting that more aberrant proteins may be generated that need to be cleared. DNA replication and repair processes were inhibited. Glutathione metabolism was enhanced, while lipid metabolism was impaired. The number of alternative splicing events increased. These changes may be related to the elevated methylation levels of cytosine and adenine in gene bodies. Both hypermethylation and hypomethylation of differentially methylated genes (DMGs) mainly occurred in exons and promoters. Some DMGs and differentially expressed genes (DEGs) were annotated to the same pathways by GO and KEGG, including protein processing in the ER, ubiquitin-mediated proteolysis, RNA transport and glutathione metabolism, suggesting that pyraclostrobin may affect gene expression by altering the methylation patterns of cytosine and adenine. Discussion Our results revealed that 5mC and 6mA in the gene body are associated with gene expression and contribute to adversity adaptation in M. oryzae. This enriched the understanding for potential mechanism of quinone inhibitor resistance, which will facilitate the development of feasible strategies for maintaining the high efficacy of this kind of fungicide.
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Affiliation(s)
- Shumei Fang
- Heilongjiang Plant Growth Regulator Engineering Technology Research Center, College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, China
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Hanxin Wang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Kaihua Qiu
- Heilongjiang Plant Growth Regulator Engineering Technology Research Center, College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Yuanyuan Pang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Chen Li
- Heilongjiang Plant Growth Regulator Engineering Technology Research Center, College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Xilong Liang
- Heilongjiang Plant Growth Regulator Engineering Technology Research Center, College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, China
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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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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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10
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Gong Y, Wang Q, Wei L, Liang W, Wang L, Lv N, Du X, Zhang J, Shen C, Xin Y, Sun L, Xu J. Genome-wide adenine N6-methylation map reveals epigenomic regulation of lipid accumulation in Nannochloropsis. PLANT COMMUNICATIONS 2024; 5:100773. [PMID: 38007614 PMCID: PMC10943562 DOI: 10.1016/j.xplc.2023.100773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/09/2023] [Accepted: 11/23/2023] [Indexed: 11/27/2023]
Abstract
Epigenetic marks on histones and DNA, such as DNA methylation at N6-adenine (6mA), play crucial roles in gene expression and genome maintenance, but their deposition and function in microalgae remain largely uncharacterized. Here, we report a genome-wide 6mA map for the model industrial oleaginous microalga Nannochloropsis oceanica produced by single-molecule real-time sequencing. Found in 0.1% of adenines, 6mA sites are mostly enriched at the AGGYV motif, more abundant in transposons and 3' untranslated regions, and associated with active transcription. Moreover, 6mA gradually increases in abundance along the direction of gene transcription and shows special positional enrichment near splicing donor and transcription termination sites. Highly expressed genes tend to show greater 6mA abundance in the gene body than do poorly expressed genes, indicating a positive interaction between 6mA and general transcription factors. Furthermore, knockout of the putative 6mA methylase NO08G00280 by genome editing leads to changes in methylation patterns that are correlated with changes in the expression of molybdenum cofactor, sulfate transporter, glycosyl transferase, and lipase genes that underlie reductions in biomass and oil productivity. By contrast, knockout of the candidate demethylase NO06G02500 results in increased 6mA levels and reduced growth. Unraveling the epigenomic players and their roles in biomass productivity and lipid metabolism lays a foundation for epigenetic engineering of industrial microalgae.
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Affiliation(s)
- Yanhai Gong
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; University of Chinese Academy of Sciences, Beijing 100049, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Qintao Wang
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; University of Chinese Academy of Sciences, Beijing 100049, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Li Wei
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; University of Chinese Academy of Sciences, Beijing 100049, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Wensi Liang
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; University of Chinese Academy of Sciences, Beijing 100049, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Lianhong Wang
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; University of Chinese Academy of Sciences, Beijing 100049, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Nana Lv
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; University of Chinese Academy of Sciences, Beijing 100049, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Xuefeng Du
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; University of Chinese Academy of Sciences, Beijing 100049, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Jiashun Zhang
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; University of Chinese Academy of Sciences, Beijing 100049, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Chen Shen
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; University of Chinese Academy of Sciences, Beijing 100049, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Yi Xin
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; University of Chinese Academy of Sciences, Beijing 100049, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Luyang Sun
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; University of Chinese Academy of Sciences, Beijing 100049, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Jian Xu
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; University of Chinese Academy of Sciences, Beijing 100049, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
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11
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Jia Q, Zhang X, Liu Q, Li J, Wang W, Ma X, Zhu B, Li S, Gong S, Tian J, Yuan M, Zhao Y, Zhou DX. A DNA adenine demethylase impairs PRC2-mediated repression of genes marked by a specific chromatin signature. Genome Biol 2023; 24:198. [PMID: 37649077 PMCID: PMC10469495 DOI: 10.1186/s13059-023-03042-4] [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: 02/16/2023] [Accepted: 08/21/2023] [Indexed: 09/01/2023] Open
Abstract
BACKGROUND The Fe (II)- and α-ketoglutarate-dependent AlkB family dioxygenases are implicated in nucleotide demethylation. AlkB homolog1 (ALKBH1) is shown to demethylate DNA adenine methylation (6mA) preferentially from single-stranded or unpaired DNA, while its demethylase activity and function in the chromatin context are unclear. RESULTS Here, we find that loss-of-function of the rice ALKBH1 gene leads to increased 6mA in the R-loop regions of the genome but has a limited effect on the overall 6mA level. However, in the context of mixed tissues, rather than on individual loci, the ALKBH1 mutation or overexpression mainly affects the expression of genes with a specific combination of chromatin modifications in the body region marked with H3K4me3 and H3K27me3 but depleted of DNA CG methylation. In the similar context of mixed tissues, further analysis reveals that the ALKBH1 protein preferentially binds to genes marked by the chromatin signature and has a function to maintain a high H3K4me3/H3K27me3 ratio by impairing the binding of Polycomb repressive complex 2 (PRC2) to the targets, which is required for both the basal and stress-induced expression of the genes. CONCLUSION Our findings unravel a function of ALKBH1 to control the balance between the antagonistic histone methylations for gene activity and provide insight into the regulatory mechanism of PRC2-mediated H3K27me3 deposition within the gene body region.
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Affiliation(s)
- Qingxiao Jia
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xinran Zhang
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Qian Liu
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Junjie Li
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Wentao Wang
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xuan Ma
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Bo Zhu
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Sheng Li
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Shicheng Gong
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jingjing Tian
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Meng Yuan
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yu Zhao
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Dao-Xiu Zhou
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China.
- Institute of Plant Science Paris-Saclay (IPS2), CNRS, INRAE, University Paris-Saclay, 91405, Orsay, France.
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12
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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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13
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Mao F, Xie H, Shi Y, Jiang S, Wang S, Wu Y. The Global Changes of N6-methyldeoxyadenosine in Response to Low Temperature in Arabidopsis thaliana and Rice. PLANTS (BASEL, SWITZERLAND) 2023; 12:2373. [PMID: 37375998 DOI: 10.3390/plants12122373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 06/12/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023]
Abstract
N6-methyldeoxyadenosine (6mA) is a recently discovered DNA modification involved in regulating plant adaptation to abiotic stresses. However, the mechanisms and changes of 6mA under cold stress in plants are not yet fully understood. Here, we conducted a genome-wide analysis of 6mA and observed that 6mA peaks were predominantly present within the gene body regions under both normal and cold conditions. In addition, the global level of 6mA increased both in Arabidopsis and rice after the cold treatment. The genes that exhibited an up-methylation showed enrichment in various biological processes, whereas there was no significant enrichment observed among the down-methylated genes. The association analysis revealed a positive correlation between the 6mA level and the gene expression level. Joint analysis of the 6mA methylome and transcriptome of Arabidopsis and rice unraveled that fluctuations in 6mA levels caused by cold exposure were not correlated to changes in transcript levels. Furthermore, we discovered that orthologous genes modified by 6mA showed high expression levels; however, only a minor amount of differentially 6mA-methylated orthologous genes were shared between Arabidopsis and rice under low-temperature conditions. In conclusion, our study provides information on the role of 6mA in response to cold stress and reveals its potential for regulating the expression of stress-related genes.
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Affiliation(s)
- Fei Mao
- National Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Bioinformatics Center, Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing 210095, China
| | - Hairong Xie
- National Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Bioinformatics Center, Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing 210095, China
| | - Yucheng Shi
- National Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Bioinformatics Center, Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing 210095, China
| | - Shasha Jiang
- National Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Bioinformatics Center, Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing 210095, China
| | - Shuai Wang
- National Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Bioinformatics Center, Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing 210095, China
| | - Yufeng Wu
- National Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Bioinformatics Center, Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing 210095, China
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14
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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: 13] [Impact Index Per Article: 13.0] [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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15
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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: 4] [Impact Index Per Article: 4.0] [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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16
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Yang M, Leng D, Zeng B, Wang T, Xu Z, Li D. Characteristics and functions of DNA N(6)-methyladenine in embryonic chicken muscle development. Poult Sci 2023; 102:102528. [PMID: 36907131 PMCID: PMC10024188 DOI: 10.1016/j.psj.2023.102528] [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: 11/11/2022] [Revised: 01/18/2023] [Accepted: 01/18/2023] [Indexed: 01/27/2023] Open
Abstract
DNA N(6)-methyladenine (DNA-6mA) is a new epigenetic mark in eukaryotes, the distribution and functions of which in genomic DNA remain unknown. Although recent studies have suggested that 6mA is present in multiple model organisms and is dynamically regulated during development, the genomic features of 6mA in avian species have yet to be elucidated. 6mA immunoprecipitation sequencing approach was used to analysis the distribution and function of 6mA in the muscle genomic DNA during embryonic chicken development. 6mA immunoprecipitation sequencing was combined with transcriptomic sequencing to reveal the role of 6mA in the regulation of gene expression and to explore possible pathways by which 6mA is involved in muscle development. We here provide evidence that 6mA modification exists widely throughout the chicken genome, and show preliminary data regarding genome-wide distribution of this epigenetic mark. Gene expression was shown to be inhibited by 6mA modification in promoter regions. In addition, the promoters of some genes related to development were modified by 6mA, indicating that 6mA may be involved in embryonic chicken development. Furthermore, 6mA may participate in muscle development and immune function by regulating HSPB8 and OASL expression. Our study improves our understanding of the distribution and function of 6mA modification in higher organisms and provide new information about differences between mammals and other vertebrates. These findings demonstrate an epigenetic role for 6mA in gene expression and potential involvement in chicken muscle development. Furthermore, the results suggest a potential epigenetic role for 6mA in avian embryonic development.
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Affiliation(s)
- Maosen Yang
- School of Pharmacy, Chengdu University, Chengdu 610106, China; College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Dong Leng
- School of Pharmacy, Chengdu University, Chengdu 610106, China; College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Bo Zeng
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Tao Wang
- School of Pharmacy, Chengdu University, Chengdu 610106, China; College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Zhongxian Xu
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637002, China
| | - Diyan Li
- School of Pharmacy, Chengdu University, Chengdu 610106, China; College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China.
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17
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DNA Modification Patterns Filtering and Analysis Using DNAModAnnot. Methods Mol Biol 2023; 2624:87-114. [PMID: 36723811 DOI: 10.1007/978-1-0716-2962-8_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Mapping DNA modifications at the base resolution is now possible at the genome level thanks to advances in sequencing technologies. Long-read sequencing data can be used to identify modified base patterns. However, the downstream analysis of Pacific Biosciences (PacBio) or Oxford Nanopore Technologies (ONT) data requires the integration of genomic annotation and comprehensive filtering to prevent the accumulation of artifact signals. We present in this chapter, a linear workflow to fully analyze modified base patterns using the DNA Modification Annotation (DNAModAnnot) package. This workflow includes a thorough filtering based on sequencing quality and false discovery rate estimation and provides tools for a global analysis of DNA modifications. Here, we provide an application example of this workflow with PacBio data and guide the user by explaining expected outputs via a fully integrated Rmarkdown script. This protocol is presented with tips showing how to adapt the provided code for annotating epigenomes of any organism according to the user needs.
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18
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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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20
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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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21
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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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22
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Tang X, Zheng P, Li X, Wu H, Wei DQ, Liu Y, Huang G. Deep6mAPred: A CNN and Bi-LSTM-based deep learning method for predicting DNA N6-methyladenosine sites across plant species. Methods 2022; 204:142-150. [PMID: 35477057 DOI: 10.1016/j.ymeth.2022.04.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/16/2022] [Accepted: 04/20/2022] [Indexed: 12/11/2022] Open
Abstract
DNA N6-methyladenine (6mA) is a key DNA modification, which plays versatile roles in the cellular processes, including regulation of gene expression, DNA repair, and DNA replication. DNA 6mA is closely associated with many diseases in the mammals and with growth as well as development of plants. Precisely detecting DNA 6mA sites is of great importance to exploration of 6mA functions. Although many computational methods have been presented for DNA 6mA prediction, there is still a wide gap in the practical application. We presented a convolution neural network (CNN) and bi-directional long-short term memory (Bi-LSTM)-based deep learning method (Deep6mAPred) for predicting DNA 6mA sites across plant species. The Deep6mAPred stacked the CNNs and the Bi-LSTMs in a paralleling manner instead of a series-connection manner. The Deep6mAPred also employed the attention mechanism for improving the representations of sequences. The Deep6mAPred reached an accuracy of 0.9556 over the independent rice dataset, far outperforming the state-of-the-art methods. The tests across plant species showed that the Deep6mAPred is of a remarkable advantage over the state of the art methods. We developed a user-friendly web application for DNA 6mA prediction, which is freely available at http://106.13.196.152:7001/ for all the scientific researchers. The Deep6mAPred would enrich tools to predict DNA 6mA sites and speed up the exploration of DNA modification.
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Affiliation(s)
- Xingyu Tang
- School of Electrical Engineering, Shaoyang University, Shaoyang, Hunan 422000, China
| | - Peijie Zheng
- School of Electrical Engineering, Shaoyang University, Shaoyang, Hunan 422000, China
| | - Xueyong Li
- School of Electrical Engineering, Shaoyang University, Shaoyang, Hunan 422000, China
| | - Hongyan Wu
- The Joint Engineering Research Center for Health Big Data Intelligent Analysis Technology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Dong-Qing Wei
- The Joint Engineering Research Center for Health Big Data Intelligent Analysis Technology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; State Key Laboratory of Microbial Metabolism, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Yuewu Liu
- College of Information and Intelligence, Hunan Agricultural University, Changsha, Hunan 410081, China
| | - Guohua Huang
- School of Electrical Engineering, Shaoyang University, Shaoyang, Hunan 422000, China.
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23
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Broad domains of histone marks in the highly compact Paramecium macronuclear genome. Genome Res 2022; 32:710-725. [PMID: 35264449 PMCID: PMC8997361 DOI: 10.1101/gr.276126.121] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 03/04/2022] [Indexed: 11/25/2022]
Abstract
The unicellular ciliate Paramecium contains a large vegetative macronucleus with several unusual characteristics, including an extremely high coding density and high polyploidy. As macronculear chromatin is devoid of heterochromatin, our study characterizes the functional epigenomic organization necessary for gene regulation and proper Pol II activity. Histone marks (H3K4me3, H3K9ac, H3K27me3) reveal no narrow peaks but broad domains along gene bodies, whereas intergenic regions are devoid of nucleosomes. Our data implicate H3K4me3 levels inside ORFs to be the main factor associated with gene expression, and H3K27me3 appears in association with H3K4me3 in plastic genes. Silent and lowly expressed genes show low nucleosome occupancy, suggesting that gene inactivation does not involve increased nucleosome occupancy and chromatin condensation. Because of a high occupancy of Pol II along highly expressed ORFs, transcriptional elongation appears to be quite different from that of other species. This is supported by missing heptameric repeats in the C-terminal domain of Pol II and a divergent elongation system. Our data imply that unoccupied DNA is the default state, whereas gene activation requires nucleosome recruitment together with broad domains of H3K4me3. In summary, gene activation and silencing in Paramecium run counter to the current understanding of chromatin biology.
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Tsukiyama S, Hasan MM, Deng HW, Kurata H. BERT6mA: prediction of DNA N6-methyladenine site using deep learning-based approaches. Brief Bioinform 2022; 23:6539171. [PMID: 35225328 PMCID: PMC8921755 DOI: 10.1093/bib/bbac053] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/28/2022] [Accepted: 01/31/2022] [Indexed: 01/29/2023] Open
Abstract
N6-methyladenine (6mA) is associated with important roles in DNA replication, DNA repair, transcription, regulation of gene expression. Several experimental methods were used to identify DNA modifications. However, these experimental methods are costly and time-consuming. To detect the 6mA and complement these shortcomings of experimental methods, we proposed a novel, deep leaning approach called BERT6mA. To compare the BERT6mA with other deep learning approaches, we used the benchmark datasets including 11 species. The BERT6mA presented the highest AUCs in eight species in independent tests. Furthermore, BERT6mA showed higher and comparable performance with the state-of-the-art models while the BERT6mA showed poor performances in a few species with a small sample size. To overcome this issue, pretraining and fine-tuning between two species were applied to the BERT6mA. The pretrained and fine-tuned models on specific species presented higher performances than other models even for the species with a small sample size. In addition to the prediction, we analyzed the attention weights generated by BERT6mA to reveal how the BERT6mA model extracts critical features responsible for the 6mA prediction. To facilitate biological sciences, the BERT6mA online web server and its source codes are freely accessible at https://github.com/kuratahiroyuki/BERT6mA.git, respectively.
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Affiliation(s)
- Sho Tsukiyama
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka 820-8502, Japan
| | - Md Mehedi Hasan
- Tulane Center for Biomedical Informatics and Genomics, Division of Biomedical Informatics and Genomics, John W. Deming Department of Medicine, School of Medicine, Tulane University, New Orleans, LA 70112, USA
| | - Hong-Wen Deng
- Tulane Center for Biomedical Informatics and Genomics, Division of Biomedical Informatics and Genomics, John W. Deming Department of Medicine, School of Medicine, Tulane University, New Orleans, LA 70112, USA
| | - Hiroyuki Kurata
- Corresponding author: Hiroyuki Kurata, Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka 820-8502, Japan. Tel: 81-948-29-7828; E-mail:
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25
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Kong Y, Cao L, Deikus G, Fan Y, Mead EA, Lai W, Zhang Y, Yong R, Sebra R, Wang H, Zhang XS, Fang G. Critical assessment of DNA adenine methylation in eukaryotes using quantitative deconvolution. Science 2022; 375:515-522. [PMID: 35113693 PMCID: PMC9382770 DOI: 10.1126/science.abe7489] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The discovery of N6-methyldeoxyadenine (6mA) across eukaryotes led to a search for additional epigenetic mechanisms. However, some studies have highlighted confounding factors that challenge the prevalence of 6mA in eukaryotes. We developed a metagenomic method to quantitatively deconvolve 6mA events from a genomic DNA sample into species of interest, genomic regions, and sources of contamination. Applying this method, we observed high-resolution 6mA deposition in two protozoa. We found that commensal or soil bacteria explained the vast majority of 6mA in insect and plant samples. We found no evidence of high abundance of 6mA in Drosophila, Arabidopsis, or humans. Plasmids used for genetic manipulation, even those from Dam methyltransferase mutant Escherichia coli, could carry abundant 6mA, confounding the evaluation of candidate 6mA methyltransferases and demethylases. On the basis of this work, we advocate for a reassessment of 6mA in eukaryotes.
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Affiliation(s)
- Yimeng Kong
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai; New York, NY 10029, USA
| | - Lei Cao
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai; New York, NY 10029, USA
| | - Gintaras Deikus
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai; New York, NY 10029, USA
| | - Yu Fan
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai; New York, NY 10029, USA
| | - Edward A. Mead
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai; New York, NY 10029, USA
| | - Weiyi Lai
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences; Beijing 100085, China
| | - Yizhou Zhang
- Department of Neurosurgery and Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York; NY 10029, USA
| | - Raymund Yong
- Department of Neurosurgery and Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York; NY 10029, USA
| | - Robert Sebra
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai; New York, NY 10029, USA
- Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai; New York, NY 10029, USA
- Sema4, a Mount Sinai venture; Stamford, CT, 06902, USA
| | - Hailin Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences; Beijing 100085, China
| | - Xue-Song Zhang
- Center for Advanced Biotechnology and Medicine, Rutgers University; New Brunswick, NJ, 08854, USA
| | - Gang Fang
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai; New York, NY 10029, USA
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26
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Abstract
[Figure: see text].
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Affiliation(s)
- Konstantinos Boulias
- Department of Pediatrics, HMS Initiative for RNA Medicine, Harvard Medical School, Boston, MA, USA
- Division of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Eric Lieberman Greer
- Department of Pediatrics, HMS Initiative for RNA Medicine, Harvard Medical School, Boston, MA, USA
- Division of Newborn Medicine, Boston Children's Hospital, Boston, MA, USA
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27
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Identification and utilization of a mutated 60S ribosomal subunit coding gene as an effective and cost-efficient selection marker for Tetrahymena genetic manipulation. Int J Biol Macromol 2022; 204:1-8. [PMID: 35122796 DOI: 10.1016/j.ijbiomac.2022.01.188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/26/2022] [Accepted: 01/28/2022] [Indexed: 01/05/2023]
Abstract
Since the onset of molecular biology, the ciliate Tetrahymena thermophila has been one of the most convenient single-celled model eukaryotes for genetics, biochemistry, and cell biology. Particularly, thanks to the availability of several different selection markers, it is possible to knock out or knock in genes at multiple genetic loci simultaneously in Tetrahymena, which makes it an excellent model ciliate for tackling complex regulatory mechanisms. Despite these selection markers are efficient for genetic manipulation, the costly drugs used for selection have highlighted the urgent demand for an additional cost-efficient and effective selection marker. Here, we found that a mutated 60S ribosomal subunit component, RPL36A, confers T. thermophila with cycloheximide resistance. On top of that, we developed a cycloheximide cassette and explored suitable transformation and selection conditions. Using the new cassette, we obtained both knockout and knock-in strains successfully at a relatively low cost. This study also provided the first evidence that a cycloheximide resistance gene can be engineered as a selection marker to completely delete a gene from the highly-polyploid somatic nucleus in Tetrahymena.
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28
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Rojas-Rojas FU, Vega-Arreguín JC. Epigenetic insight into regulatory role of chromatin covalent modifications in lifecycle and virulence of Phytophthora. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:445-457. [PMID: 33876568 DOI: 10.1111/1758-2229.12954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 04/12/2021] [Accepted: 04/14/2021] [Indexed: 06/12/2023]
Abstract
The Oomycota phylum includes fungi-like filamentous microorganisms classified as plant pathogens. The most destructive genus within oomycetes is Phytophthora, which causes diseases in plants of economic importance in agriculture, forestry and ornamental. Phytophthora species are widespread worldwide and some of them enable adaptation to different hosts and environmental changes. The development of sexual and asexual reproductive structures and the secretion of proteins to control plant immunity are critical for the adaptative lifestyle. However, molecular mechanisms underlying the adaptation of Phytophthora to different hosts and environmental changes are poorly understood. In the last decade, the role of epigenetics has gained attention, and important evidence has demonstrated the potential role of chromatin covalent modifications, such as DNA methylation and histone acetylation/methylation, in the regulation of gene expression during Phytophthora development and plant infection. Here, we review for the first time the evidence of the potential role of chromatin covalent modifications in the lifecycle of the phytopathogenic genus Phytophthora, including virulence, and host and environment adaptation processes.
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Affiliation(s)
- Fernando Uriel Rojas-Rojas
- Laboratorio de Ciencias AgroGenómicas, Escuela Nacional de Estudios Superiores Unidad León, Universidad Nacional Autónoma de México (ENES - León, UNAM), Blvd. UNAM 2011, León, Guanajuato, 37684, Mexico
- Laboratorio Nacional PlanTECC, Escuela Nacional de Estudios Superiores Unidad León, Universidad Nacional Autónoma de México (ENES - León, UNAM), Blvd. UNAM 2011, León, Guanajuato, 37684, Mexico
| | - Julio C Vega-Arreguín
- Laboratorio de Ciencias AgroGenómicas, Escuela Nacional de Estudios Superiores Unidad León, Universidad Nacional Autónoma de México (ENES - León, UNAM), Blvd. UNAM 2011, León, Guanajuato, 37684, Mexico
- Laboratorio Nacional PlanTECC, Escuela Nacional de Estudios Superiores Unidad León, Universidad Nacional Autónoma de México (ENES - León, UNAM), Blvd. UNAM 2011, León, Guanajuato, 37684, Mexico
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29
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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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New contribution to epigenetic studies: Isolation of micronuclei with high purity and DNA integrity in the model ciliated protist, Tetrahymena thermophila. Eur J Protistol 2021; 80:125804. [PMID: 34062315 DOI: 10.1016/j.ejop.2021.125804] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 03/31/2021] [Accepted: 05/04/2021] [Indexed: 10/24/2022]
Abstract
The ciliated protist Tetrahymena thermophila is a well-known model organism with typical nuclear dimorphism containing a somatic macronucleus (MAC) and a germline micronucleus (MIC). The presence in the same cell compartment of two nuclei with distinctly different structural and functional properties provides an ideal model system to explore mechanisms of genome maintenance. Although methods for the isolation of MIC have been available for many years, cross-contamination and DNA degradation remain unresolved. Here, we describe a reliable and quick method to isolate MIC with high purity and DNA integrity in T. thermophila. Different factors are examined to optimize the MIC purification. The MAC contamination ratio in purified MIC is about 0.19% and DNA integrity of purified MIC is maintained. We also establish a more accurate method to detect the contamination rate of nuclei including microscopic observation and PCR detection. This study will facilitate further epigenetic research in Tetrahymena.
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31
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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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32
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Liu Y, Nan B, Niu J, Kapler GM, Gao S. An Optimized and Versatile Counter-Flow Centrifugal Elutriation Workflow to Obtain Synchronized Eukaryotic Cells. Front Cell Dev Biol 2021; 9:664418. [PMID: 33959616 PMCID: PMC8093812 DOI: 10.3389/fcell.2021.664418] [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: 02/05/2021] [Accepted: 03/23/2021] [Indexed: 11/21/2022] Open
Abstract
Cell synchronization is a powerful tool to understand cell cycle events and its regulatory mechanisms. Counter-flow centrifugal elutriation (CCE) is a more generally desirable method to synchronize cells because it does not significantly alter cell behavior and/or cell cycle progression, however, adjusting specific parameters in a cell type/equipment-dependent manner can be challenging. In this paper, we used the unicellular eukaryotic model organism, Tetrahymena thermophila as a testing system for optimizing CCE workflow. Firstly, flow cytometry conditions were identified that reduced nuclei adhesion and improved the assessment of cell cycle stage. We then systematically examined how to achieve the optimal conditions for three critical factors affecting the outcome of CCE, including loading flow rate, collection flow rate and collection volume. Using our optimized workflow, we obtained a large population of highly synchronous G1-phase Tetrahymena as measured by 5-ethynyl-2'-deoxyuridine (EdU) incorporation into nascent DNA strands, bulk DNA content changes by flow cytometry, and cell cycle progression by light microscopy. This detailed protocol can be easily adapted to synchronize other eukaryotic cells.
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Affiliation(s)
- Yongqiang Liu
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Ministry of Education Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Bei Nan
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Ministry of Education Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Junhua Niu
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Ministry of Education Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Geoffrey M. Kapler
- Department of Molecular and Cellular Medicine, Texas A&M University, College Station, TX, United States
| | - Shan Gao
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Ministry of Education Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
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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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Liu B, Wang H. Detection of N 6-Methyladenine in Eukaryotes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1280:83-95. [PMID: 33791976 DOI: 10.1007/978-3-030-51652-9_6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
DNA N6-methyladenine (6mA) is a chemical modification at the N6-positon of adenine. In the last decades, 6mA had been found in genome from numerous prokaryotic species, but only existed in a few lower eukaryotes. In prokaryotes, 6mA plays an important role in restriction-modification, DNA replication, and DNA mismatch repair. Because of the too low abundance of 6mA, it was long-stalled whether 6mA existed in multicellular eukaryotes and playing any functions, particularly in mammals. In recent years, partially benefitting from the advances in analytical methods, 6mA was found in the genomes from Drosophila melanogaster, Chlamydomonas algae, Caenorhabditis elegans, zebrafish, Xenopus laevis and mouse embryonic stem cells and even in the human genome. The 6mA was dynamic changed in early embryonic development of fly and zebrafish and much more enriched in gene body of transposons in fly, repetitive regions in zebrafish, around the transcription start sites in Chlamydomonas, and widespread distribution in C. elegans, indicating 6mA probably playing different functions in different species. Meanwhile, 6mA methylases and demethylases were found in fly, worm, and Chlamydomonas. In this chapter, we will briefly review the distribution, regulation, and function of 6mA in eukaryotes and focus on the advances of 6mA analysis methods, especially LC-MS/MS, immunoprecipitation, next-generation sequencing, and single-molecule real-time sequencing technology.
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Affiliation(s)
- Baodong Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Hailin Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China. .,University of Chinese Academy of Sciences, Beijing, China.
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35
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The epigenetic roles of DNA N6-Methyladenine (6mA) modification in eukaryotes. Cancer Lett 2020; 494:40-46. [DOI: 10.1016/j.canlet.2020.08.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/11/2020] [Accepted: 08/21/2020] [Indexed: 12/17/2022]
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36
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Bochtler M, Fernandes H. DNA adenine methylation in eukaryotes: Enzymatic mark or a form of DNA damage? Bioessays 2020; 43:e2000243. [PMID: 33244833 DOI: 10.1002/bies.202000243] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/30/2020] [Accepted: 11/02/2020] [Indexed: 12/16/2022]
Abstract
6-methyladenine (6mA) is fairly abundant in nuclear DNA of basal fungi, ciliates and green algae. In these organisms, 6mA is maintained near transcription start sites in ApT context by a parental-strand instruction dependent maintenance methyltransferase and is positively associated with transcription. In animals and plants, 6mA levels are high only in organellar DNA. The 6mA levels in nuclear DNA are very low. They are attributable to nucleotide salvage and the activity of otherwise mitochondrial METTL4, and may be considered as a price that cells pay for adenine methylation in RNA and/or organellar DNA. Cells minimize this price by sanitizing dNTP pools to limit 6mA incorporation, and by converting 6mA that has been incorporated into DNA back to adenine. Hence, 6mA in nuclear DNA should be described as an epigenetic mark only in basal fungi, ciliates and green algae, but not in animals and plants.
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Affiliation(s)
- Matthias Bochtler
- International Institute of Molecular and Cell Biology, Warsaw, Poland.,Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Humberto Fernandes
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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37
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Rzeszutek I, Maurer-Alcalá XX, Nowacki M. Programmed genome rearrangements in ciliates. Cell Mol Life Sci 2020; 77:4615-4629. [PMID: 32462406 PMCID: PMC7599177 DOI: 10.1007/s00018-020-03555-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 05/11/2020] [Accepted: 05/15/2020] [Indexed: 12/14/2022]
Abstract
Ciliates are a highly divergent group of unicellular eukaryotes with separate somatic and germline genomes found in distinct dimorphic nuclei. This characteristic feature is tightly linked to extremely laborious developmentally regulated genome rearrangements in the development of a new somatic genome/nuclei following sex. The transformation from germline to soma genome involves massive DNA elimination mediated by non-coding RNAs, chromosome fragmentation, as well as DNA amplification. In this review, we discuss the similarities and differences in the genome reorganization processes of the model ciliates Paramecium and Tetrahymena (class Oligohymenophorea), and the distantly related Euplotes, Stylonychia, and Oxytricha (class Spirotrichea).
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Affiliation(s)
- Iwona Rzeszutek
- Institute of Biology and Biotechnology, Department of Biotechnology, University of Rzeszow, Pigonia 1, 35-310, Rzeszow, Poland.
| | - Xyrus X Maurer-Alcalá
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012, Bern, Switzerland
| | - Mariusz Nowacki
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012, Bern, Switzerland.
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38
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Wang Y, Sheng Y, Liu Y, Zhang W, Cheng T, Duan L, Pan B, Qiao Y, Liu Y, Gao S. A distinct class of eukaryotic MT-A70 methyltransferases maintain symmetric DNA N6-adenine methylation at the ApT dinucleotides as an epigenetic mark associated with transcription. Nucleic Acids Res 2020; 47:11771-11789. [PMID: 31722409 PMCID: PMC7145601 DOI: 10.1093/nar/gkz1053] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 10/21/2019] [Accepted: 10/24/2019] [Indexed: 12/18/2022] Open
Abstract
Rediscovered as a potential eukaryotic epigenetic mark, DNA N6-adenine methylation (6mA) varies across species in abundance and its relationships with transcription. Here we characterize AMT1—representing a distinct MT-A70 family methyltransferase—in the ciliate Tetrahymena thermophila. AMT1 loss-of-function leads to severe defects in growth and development. Single Molecule, Real-Time (SMRT) sequencing reveals that AMT1 is required for the bulk of 6mA and all symmetric methylation at the ApT dinucleotides. The detection of hemi-methylated ApT sites suggests a semi-conservative mechanism for maintaining symmetric methylation. AMT1 affects expression of many genes; in particular, RAB46, encoding a Rab family GTPase involved in contractile vacuole function, is likely a direct target. The distribution of 6mA resembles H3K4 methylation and H2A.Z, two conserved epigenetic marks associated with RNA polymerase II transcription. Furthermore, strong 6mA and nucleosome positioning in wild-type cells is attenuated in ΔAMT1 cells. Our results support that AMT1-catalyzed 6mA is an integral part of the transcription-associated epigenetic landscape. AMT1 homologues are generally found in protists and basal fungi featuring ApT hyper-methylation associated with transcription, which are missing in animals, plants, and true fungi. This dichotomy of 6mA functions and the underlying molecular mechanisms may have implications in eukaryotic diversification.
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Affiliation(s)
- Yuanyuan Wang
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China.,MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Yalan Sheng
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China.,MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Yongqiang Liu
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China.,MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Wenxin Zhang
- School of Life Science, Anhui Agricultural University, Hefei 230036, China
| | - Ting Cheng
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China.,MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Lili Duan
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China.,MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Bo Pan
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China.,MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Yu Qiao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China.,MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Yifan Liu
- Department of Pathology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Shan Gao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China.,MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
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39
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Adenine DNA methylation, 3D genome organization, and gene expression in the parasite Trichomonas vaginalis. Proc Natl Acad Sci U S A 2020; 117:13033-13043. [PMID: 32461362 DOI: 10.1073/pnas.1917286117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Trichomonas vaginalis is a common sexually transmitted parasite that colonizes the human urogenital tract causing infections that range from asymptomatic to highly inflammatory. Recent works have highlighted the importance of histone modifications in the regulation of transcription and parasite pathogenesis. However, the nature of DNA methylation in the parasite remains unexplored. Using a combination of immunological techniques and ultrahigh-performance liquid chromatography (UHPLC), we analyzed the abundance of DNA methylation in strains with differential pathogenicity demonstrating that N6-methyladenine (6mA), and not 5-methylcytosine (5mC), is the main DNA methylation mark in T. vaginalis Genome-wide distribution of 6mA reveals that this mark is enriched at intergenic regions, with a preference for certain superfamilies of DNA transposable elements. We show that 6mA in T. vaginalis is associated with silencing when present on genes. Interestingly, bioinformatics analysis revealed the presence of transcriptionally active or repressive intervals flanked by 6mA-enriched regions, and results from chromatin conformation capture (3C) experiments suggest these 6mA flanked regions are in close spatial proximity. These associations were disrupted when parasites were treated with the demethylation activator ascorbic acid. This finding revealed a role for 6mA in modulating three-dimensional (3D) chromatin structure and gene expression in this divergent member of the Excavata.
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40
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Lu Y, Zhou DX, Zhao Y. Understanding epigenomics based on the rice model. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2020; 133:1345-1363. [PMID: 31897514 DOI: 10.1007/s00122-019-03518-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 12/18/2019] [Indexed: 05/26/2023]
Abstract
The purpose of this paper provides a comprehensive overview of the recent researches on rice epigenomics, including DNA methylation, histone modifications, noncoding RNAs, and three-dimensional genomics. The challenges and perspectives for future research in rice are discussed. Rice as a model plant for epigenomic studies has much progressed current understanding of epigenetics in plants. Recent results on rice epigenome profiling and three-dimensional chromatin structure studies reveal specific features and implication in gene regulation during rice plant development and adaptation to environmental changes. Results on rice chromatin regulator functions shed light on mechanisms of establishment, recognition, and resetting of epigenomic information in plants. Cloning of several rice epialleles associated with important agronomic traits highlights importance of epigenomic variation in rice plant growth, fitness, and yield. In this review, we summarize and analyze recent advances in rice epigenomics and discuss challenges and directions for future research in the field.
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Affiliation(s)
- Yue Lu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Dao-Xiu Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
- Institute of Plant Science of Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University Paris-Saclay, 91405, Orsay, France
| | - Yu Zhao
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China.
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41
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Li Y, Chen X, Wu K, Pan J, Long H, Yan Y. Characterization of Simple Sequence Repeats (SSRs) in Ciliated Protists Inferred by Comparative Genomics. Microorganisms 2020; 8:microorganisms8050662. [PMID: 32370063 PMCID: PMC7285179 DOI: 10.3390/microorganisms8050662] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 04/24/2020] [Accepted: 04/26/2020] [Indexed: 01/02/2023] Open
Abstract
Simple sequence repeats (SSRs) are prevalent in the genomes of all organisms. They are widely used as genetic markers, and are insertion/deletion mutation hotspots, which directly influence genome evolution. However, little is known about such important genomic components in ciliated protists, a large group of unicellular eukaryotes with extremely long evolutionary history and genome diversity. With recent publications of multiple ciliate genomes, we start to get a chance to explore perfect SSRs with motif size 1-100 bp and at least three motif repeats in nine species of two ciliate classes, Oligohymenophorea and Spirotrichea. We found that homopolymers are the most prevalent SSRs in these A/T-rich species, with AAA (lysine, charged amino acid; also seen as an SSR with one-adenine motif repeated three times) being the codons repeated at the highest frequencies in coding SSR regions, consistent with the widespread alveolin proteins rich in lysine repeats as found in Tetrahymena. Micronuclear SSRs are universally more abundant than the macronuclear ones of the same motif-size, except for the 8-bp-motif SSRs in extensively fragmented chromosomes. Both the abundance and A/T content of SSRs decrease as motif-size increases, while the abundance is positively correlated with the A/T content of the genome. Also, smaller genomes have lower proportions of coding SSRs out of all SSRs in Paramecium species. This genome-wide and cross-species analysis reveals the high diversity of SSRs and reflects the rapid evolution of these simple repetitive elements in ciliate genomes.
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42
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The completed macronuclear genome of a model ciliate Tetrahymena thermophila and its application in genome scrambling and copy number analyses. SCIENCE CHINA-LIFE SCIENCES 2020; 63:1534-1542. [PMID: 32297047 DOI: 10.1007/s11427-020-1689-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 03/26/2020] [Indexed: 01/03/2023]
Abstract
The ciliate Tetrahymena thermophila has been a powerful model system for molecular and cellular biology. However, some investigations have been limited due to the incomplete closure and sequencing of the macronuclear genome assembly, which for many years has been stalled at 1,158 scaffolds, with large sections of unknown sequences (available in Tetrahymena Genome Database, TGD, http://ciliate.org/ ). Here we completed the first chromosome-level Tetrahymena macronuclear genome assembly, with approximately 300× long Single Molecule, Real-Time reads of the wild-type SB210 cells-the reference strain for the initial macronuclear genome sequencing project. All 181 chromosomes were capped with two telomeres and gaps were entirely closed. The completed genome shows significant improvements over the current assembly (TGD 2014) in both chromosome structure and sequence integrity. The majority of previously identified gene models shown in TGD were retained, with the addition of 36 new genes and 883 genes with modified gene models. The new genome and annotation were incorporated into TGD. This new genome allows for pursuit in some underexplored areas that were far more challenging previously; two of them, genome scrambling and chromosomal copy number, were investigated in this study. We expect that the completed macronuclear genome will facilitate many studies in Tetrahymena biology, as well as multiple lines of research in other eukaryotes.
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43
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Shipony Z, Marinov GK, Swaffer MP, Sinnott-Armstrong NA, Skotheim JM, Kundaje A, Greenleaf WJ. Long-range single-molecule mapping of chromatin accessibility in eukaryotes. Nat Methods 2020; 17:319-327. [PMID: 32042188 PMCID: PMC7968351 DOI: 10.1038/s41592-019-0730-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 12/22/2019] [Indexed: 02/06/2023]
Abstract
Mapping open chromatin regions has emerged as a widely used tool for identifying active regulatory elements in eukaryotes. However, existing approaches, limited by reliance on DNA fragmentation and short-read sequencing, cannot provide information about large-scale chromatin states or reveal coordination between the states of distal regulatory elements. We have developed a method for profiling the accessibility of individual chromatin fibers, a single-molecule long-read accessible chromatin mapping sequencing assay (SMAC-seq), enabling the simultaneous, high-resolution, single-molecule assessment of chromatin states at multikilobase length scales. Our strategy is based on combining the preferential methylation of open chromatin regions by DNA methyltransferases with low sequence specificity, in this case EcoGII, an N6-methyladenosine (m6A) methyltransferase, and the ability of nanopore sequencing to directly read DNA modifications. We demonstrate that aggregate SMAC-seq signals match bulk-level accessibility measurements, observe single-molecule nucleosome and transcription factor protection footprints, and quantify the correlation between chromatin states of distal genomic elements.
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Affiliation(s)
- Zohar Shipony
- Department of Genetics, Stanford University, Stanford, CA, USA
| | | | | | | | - Jan M Skotheim
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Anshul Kundaje
- Department of Genetics, Stanford University, Stanford, CA, USA
- Department of Computer Science, Stanford University, Stanford, CA, USA
| | - William J Greenleaf
- Department of Genetics, Stanford University, Stanford, CA, USA.
- Department of Applied Physics, Stanford University, Stanford, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
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44
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Wang Y, Jiang Y, Liu Y, Li Y, Katz LA, Gao F, Yan Y. Comparative Studies on the Polymorphism and Copy Number Variation of mtSSU rDNA in Ciliates (Protista, Ciliophora): Implications for Phylogenetic, Environmental, and Ecological Research. Microorganisms 2020; 8:E316. [PMID: 32106521 PMCID: PMC7142639 DOI: 10.3390/microorganisms8030316] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 01/21/2023] Open
Abstract
While nuclear small subunit ribosomal DNA (nSSU rDNA) is the most commonly-used gene marker in studying phylogeny, ecology, abundance, and biodiversity of microbial eukaryotes, mitochondrial small subunit ribosomal DNA (mtSSU rDNA) provides an alternative. Recently, both copy number variation and sequence variation of nSSU rDNA have been demonstrated for diverse organisms, which can contribute to misinterpretation of microbiome data. Given this, we explore patterns for mtSSU rDNA among 13 selected ciliates (representing five classes), a major component of microbial eukaryotes, estimating copy number and sequence variation and comparing to that of nSSU rDNA. Our study reveals: (1) mtSSU rDNA copy number variation is substantially lower than that for nSSU rDNA; (2) mtSSU rDNA copy number ranges from 1.0 × 104 to 8.1 × 105; (3) a most common sequence of mtSSU rDNA is also found in each cell; (4) the sequence variation of mtSSU rDNA are mainly indels in poly A/T regions, and only half of species have sequence variation, which is fewer than that for nSSU rDNA; and (5) the polymorphisms between haplotypes of mtSSU rDNA would not influence the phylogenetic topology. Together, these data provide more insights into mtSSU rDNA as a powerful marker especially for microbial ecology studies.
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Affiliation(s)
- Yurui Wang
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; (Y.W.); (Y.J.); (Y.L.); (Y.L.); (F.G.)
- Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Yaohan Jiang
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; (Y.W.); (Y.J.); (Y.L.); (Y.L.); (F.G.)
- Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Yongqiang Liu
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; (Y.W.); (Y.J.); (Y.L.); (Y.L.); (F.G.)
- Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Yuan Li
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; (Y.W.); (Y.J.); (Y.L.); (Y.L.); (F.G.)
- Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Laura A. Katz
- Department of Biological Sciences, Smith College, Northampton, MA 01063, USA;
| | - Feng Gao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; (Y.W.); (Y.J.); (Y.L.); (Y.L.); (F.G.)
- Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Ying Yan
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; (Y.W.); (Y.J.); (Y.L.); (Y.L.); (F.G.)
- Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
- Department of Biological Sciences, Smith College, Northampton, MA 01063, USA;
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45
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Gao Y, Gong R, Jiang Y, Pan B, Li Y, Warren A, Jiang J, Gao F. Morphogenetic characters of the model ciliate Euplotes vannus (Ciliophora, Spirotrichea): Notes on cortical pattern formation during conjugational and postconjugational reorganization. Eur J Protistol 2020; 73:125675. [PMID: 32036251 DOI: 10.1016/j.ejop.2020.125675] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 01/12/2020] [Accepted: 01/21/2020] [Indexed: 11/26/2022]
Abstract
Ciliated protists represent a morphologically and genetically distinct group of single-celled eukaryotes which can reproduce asexually and sexually. Morphogenesis occurs in both asexual and sexual modes of reproduction which is of interest for researchers investigating cell differentiation, regeneration, systematics and evolution. However, studies of morphogenesis have concentrated almost entirely on the asexual mode. Here we use protargol staining to investigate the morphogenetic processes during sexual reproduction in the model species Euplotes vannus (Müller). The major events include: (1) two rounds of morphogenesis occur during sexual reproduction, i.e., conjugational and postconjugational reorganization; (2) in both processes the oral primordium is generated de novo in a pouch beneath the cortex; (3) the frontoventral-transverse cirri anlagen are formed de novo and fragment in a 3:3:3:3:2 pattern; (4) the leftmost cirrus and the paroral membrane do not change during conjugational morphogenesis, but reorganize de novo during postconjugational morphogenesis; (5) marginal cirral anlagen are formed de novo in both morphogenetic processes; (6) two or three caudal cirri are formed at the ends of the rightmost two or three old dorsal kineties; (7) the dorsal kineties are retained entirely. These results can serve as reference to investigate the morphogenetic events in the different stages of sexual reproduction.
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Affiliation(s)
- Yunyi Gao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, China
| | - Ruitao Gong
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, China
| | - Yaohan Jiang
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, China
| | - Bo Pan
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
| | - Yuan Li
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
| | - Alan Warren
- Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
| | - Jiamei Jiang
- Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China.
| | - Feng Gao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, China.
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Conjugation in Euplotes raikovi (Protista, Ciliophora): New Insights into Nuclear Events and Macronuclear Development from Micronucleate and Amicronucleate Cells. Microorganisms 2020; 8:microorganisms8020162. [PMID: 31979289 PMCID: PMC7074782 DOI: 10.3390/microorganisms8020162] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/16/2020] [Accepted: 01/20/2020] [Indexed: 01/08/2023] Open
Abstract
Ciliates form a distinct group of single-celled eukaryotes that host two types of nuclei (micro and macronucleus) in the same cytoplasm and have a special sexual process known as conjugation, which involves mitosis, meiosis, fertilization, nuclear differentiation, and development. Due to their high species diversity, ciliates have evolved different patterns of nuclear events during conjugation. In the present study, we investigate these events in detail in the marine species Euplotes raikovi. Our results indicate that: (i) conjugation lasts for about 50 h, the longest stage being the development of the new macronucleus (ca. 36 h); (ii) there are three prezygotic micronuclear divisions (mitosis and meiosis I and II) and two postzygotic synkaryon divisions; and (iii) a fragment of the parental macronucleus fuses with the new developing macronucleus. In addition, we describe for the first time conjugation in amicronucleate E. raikovi cells. When two amicronucleate cells mate, they separate after about 4 h without evident nuclear changes; when one amicronucleate cell mates with a micronucleate cell, the micronucleus undergoes regular prezygotic divisions to form migratory and stationary pronuclei, but the two pronuclei fuse in the same cell. In the amicronucleate cell, the parental macronucleus breaks into fragments, which are then recovered to form a new functional macronucleus. These results add new information on the process of conjugation in both micronucleate and amicronucleate Euplotes cells.
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Comparative Transcriptome Analyses during the Vegetative Cell Cycle in the Mono-Cellular Organism Pseudokeronopsis erythrina (Alveolata, Ciliophora). Microorganisms 2020; 8:microorganisms8010108. [PMID: 31940957 PMCID: PMC7022673 DOI: 10.3390/microorganisms8010108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 01/18/2023] Open
Abstract
Studies focusing on molecular mechanisms of cell cycles have been lagging in unicellular eukaryotes compared to other groups. Ciliates, a group of unicellular eukaryotes, have complex cell division cycles characterized by multiple events. During their vegetative cell cycle, ciliates undergo macronuclear amitosis, micronuclear mitosis, stomatogenesis and somatic cortex morphogenesis, and cytokinesis. Herein, we used the hypotrich ciliate Pseudokeronopsis erythrina, whose morphogenesis has been well studied, to examine molecular mechanisms of ciliate vegetative cell cycles. Single-cell transcriptomes of the growth (G) and cell division (D) stages were compared. The results showed that (i) More than 2051 significantly differentially expressed genes (DEGs) were detected, among which 1545 were up-regulated, while 256 were down-regulated at the D stage. Of these, 11 randomly picked DEGs were validated by reverse transcription quantitative polymerase chain reaction (RT-qPCR); (ii) Enriched DEGs during the D stage of the vegetative cell cycle of P. erythrina were involved in development, cortex modifications, and several organelle-related biological processes, showing correspondence of molecular evidence to morphogenetic changes for the first time; (iii) Several individual components of molecular mechanisms of ciliate vegetative division, the sexual cell cycle and cellular regeneration overlap; and (iv) The P. erythrina cell cycle and division have the same essential components as other eukaryotes, including cyclin-dependent kinases (CDKs), cyclins, and genes closely related to cell proliferation, indicating the conserved nature of this biological process. Further studies are needed focusing on detailed inventory and gene interactions that regulate specific ciliated cell-phase events.
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Liang Z, Riaz A, Chachar S, Ding Y, Du H, Gu X. Epigenetic Modifications of mRNA and DNA in Plants. MOLECULAR PLANT 2020; 13:14-30. [PMID: 31863849 DOI: 10.1016/j.molp.2019.12.007] [Citation(s) in RCA: 115] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/22/2019] [Accepted: 12/05/2019] [Indexed: 05/21/2023]
Abstract
Advances in the detection and mapping of messenger RNA (mRNA) N6-methyladenosine (m6A) and 5-methylcytosine (m5C), and DNA N6-methyldeoxyadenosine (6mA) redefined our understanding of these modifications as additional tiers of epigenetic regulation. In plants, the most prevalent internal mRNA modifications, m6A and m5C, play crucial and dynamic roles in many processes, including embryo development, stem cell fate determination, trichome branching, leaf morphogenesis, floral transition, stress responses, fruit ripening, and root development. The newly identified and widespread epigenetic marker 6mA DNA methylation is associated with gene expression, plant development, and stress responses. Here, we review the latest research progress on mRNA and DNA epigenetic modifications, including the detection, dynamics, distribution, functions, regulatory proteins, and evolution, with a focus on m6A, m5C, and 6mA. We also provide some perspectives on future research of the newly identified and unknown epigenetic modifications of mRNA and DNA in plants.
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Affiliation(s)
- Zhe Liang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Centre for Organismal Studies, Heidelberg University, Heidelberg 69120, Germany
| | - Adeel Riaz
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Sadaruddin Chachar
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yike Ding
- Department of Entomology, University of California Riverside, Riverside, CA 92521, USA
| | - Hai Du
- College of Agronomy and Biotechnology, Southwest University, Chongqing 400715, China
| | - Xiaofeng Gu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
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Basith S, Manavalan B, Shin TH, Lee G. SDM6A: A Web-Based Integrative Machine-Learning Framework for Predicting 6mA Sites in the Rice Genome. MOLECULAR THERAPY. NUCLEIC ACIDS 2019; 18:131-141. [PMID: 31542696 PMCID: PMC6796762 DOI: 10.1016/j.omtn.2019.08.011] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/30/2019] [Accepted: 08/08/2019] [Indexed: 12/19/2022]
Abstract
DNA N6-adenine methylation (6mA) is an epigenetic modification in prokaryotes and eukaryotes. Identifying 6mA sites in rice genome is important in rice epigenetics and breeding, but non-random distribution and biological functions of these sites remain unclear. Several machine-learning tools can identify 6mA sites but show limited prediction accuracy, which limits their usability in epigenetic research. Here, we developed a novel computational predictor, called the Sequence-based DNA N6-methyladenine predictor (SDM6A), which is a two-layer ensemble approach for identifying 6mA sites in the rice genome. Unlike existing methods, which are based on single models with basic features, SDM6A explores various features, and five encoding methods were identified as appropriate for this problem. Subsequently, an optimal feature set was identified from encodings, and corresponding models were developed individually using support vector machine and extremely randomized tree. First, all five single models were integrated via ensemble approach to define the class for each classifier. Second, two classifiers were integrated to generate a final prediction. SDM6A achieved robust performance on cross-validation and independent evaluation, with average accuracy and Matthews correlation coefficient (MCC) of 88.2% and 0.764, respectively. Corresponding metrics were 4.7%-11.0% and 2.3%-5.5% higher than those of existing methods, respectively. A user-friendly, publicly accessible web server (http://thegleelab.org/SDM6A) was implemented to predict novel putative 6mA sites in rice genome.
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Affiliation(s)
- Shaherin Basith
- Department of Physiology, Ajou University School of Medicine, Suwon, Republic of Korea
| | | | - Tae Hwan Shin
- Department of Physiology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Gwang Lee
- Department of Physiology, Ajou University School of Medicine, Suwon, Republic of Korea.
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Saettone A, Ponce M, Nabeel-Shah S, Fillingham J. RACS: rapid analysis of ChIP-Seq data for contig based genomes. BMC Bioinformatics 2019; 20:533. [PMID: 31664892 PMCID: PMC6819487 DOI: 10.1186/s12859-019-3100-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 09/13/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Chromatin immunoprecipitation coupled to next generation sequencing (ChIP-Seq) is a widely-used molecular method to investigate the function of chromatin-related proteins by identifying their associated DNA sequences on a genomic scale. ChIP-Seq generates large quantities of data that is difficult to process and analyze, particularly for organisms with a contig-based sequenced genomes that typically have minimal annotation on their associated set of genes other than their associated coordinates primarily predicted by gene finding programs. Poorly annotated genome sequence makes comprehensive analysis of ChIP-Seq data difficult and as such standardized analysis pipelines are lacking. RESULTS We present a one-stop computational pipeline, "Rapid Analysis of ChIP-Seq data" (RACS), that utilizes traditional High-Performance Computing (HPC) techniques in association with open source tools for processing and analyzing raw ChIP-Seq data. RACS is an open source computational pipeline available from any of the following repositories https://bitbucket.org/mjponce/RACS or https://gitrepos.scinet.utoronto.ca/public/?a=summary&p=RACS . RACS is particularly useful for ChIP-Seq in organisms with contig-based genomes that have poor gene annotation to aid protein function discovery.To test the performance and efficiency of RACS, we analyzed ChIP-Seq data previously published in a model organism Tetrahymena thermophila which has a contig-based genome. We assessed the generality of RACS by analyzing a previously published data set generated using the model organism Oxytricha trifallax, whose genome sequence is also contig-based with poor annotation. CONCLUSIONS The RACS computational pipeline presented in this report is an efficient and reliable tool to analyze genome-wide raw ChIP-Seq data generated in model organisms with poorly annotated contig-based genome sequence. Because RACS segregates the found read accumulations between genic and intergenic regions, it is particularly efficient for rapid downstream analyses of proteins involved in gene expression.
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Affiliation(s)
- Alejandro Saettone
- Department of Chemistry and Biology, Ryerson University, 350 Victoria St, Toronto, M5B 2K3 Canada
| | - Marcelo Ponce
- SciNet High Performance Computing Consortium, University of Toronto, 661 University Ave, Toronto, M5G 1M1 Canada
| | - Syed Nabeel-Shah
- Department of Molecular Genetics, University of Toronto, 1 King’s College Cir, Toronto, M5S 1A8 Canada
| | - Jeffrey Fillingham
- Department of Chemistry and Biology, Ryerson University, 350 Victoria St, Toronto, M5B 2K3 Canada
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