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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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2
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Xie L, Zhang X, Xie J, Xu Y, Li XJ, Lin L. Emerging Roles for DNA 6mA and RNA m6A Methylation in Mammalian Genome. Int J Mol Sci 2023; 24:13897. [PMID: 37762200 PMCID: PMC10531503 DOI: 10.3390/ijms241813897] [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: 08/10/2023] [Revised: 08/25/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
Epigenetic methylation has been shown to play an important role in transcriptional regulation and disease pathogenesis. Recent advancements in detection techniques have identified DNA N6-methyldeoxyadenosine (6mA) and RNA N6-methyladenosine (m6A) as methylation modifications at the sixth position of adenine in DNA and RNA, respectively. While the distributions and functions of 6mA and m6A have been extensively studied in prokaryotes, their roles in the mammalian brain, where they are enriched, are still not fully understood. In this review, we provide a comprehensive summary of the current research progress on 6mA and m6A, as well as their associated writers, erasers, and readers at both DNA and RNA levels. Specifically, we focus on the potential roles of 6mA and m6A in the fundamental biological pathways of the mammalian genome and highlight the significant regulatory functions of 6mA in neurodegenerative diseases.
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Affiliation(s)
| | | | | | | | | | - Li Lin
- Guangdong Key Laboratory of Non-Human Primate Research, Laboratory of CNS Regeneration (Ministry of Education), Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou 510632, China; (L.X.); (X.Z.); (J.X.); (Y.X.); (X.-J.L.)
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3
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Jin D, Li C, Chen X, Byerly A, Stover NA, Zhang T, Shao C, Wang Y. Comparative genome analysis of three euplotid protists provides insights into the evolution of nanochromosomes in unicellular eukaryotic organisms. MARINE LIFE SCIENCE & TECHNOLOGY 2023; 5:300-315. [PMID: 37637252 PMCID: PMC10449743 DOI: 10.1007/s42995-023-00175-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 04/12/2023] [Indexed: 08/29/2023]
Abstract
One of the most diverse clades of ciliated protozoa, the class Spirotrichea, displays a series of unique characters in terms of eukaryotic macronuclear (MAC) genome, including high fragmentation that produces nanochromosomes. However, the genomic diversity and evolution of nanochromosomes and gene families for spirotrich MAC genomes are poorly understood. In this study, we assemble the MAC genome of a representative euplotid (a new model organism in Spirotrichea) species, Euplotes aediculatus. Our results indicate that: (a) the MAC genome includes 35,465 contigs with a total length of 97.3 Mb and a contig N50 of 3.4 kb, and contains 13,145 complete nanochromosomes and 43,194 predicted genes, with the majority of these nanochromosomes containing tiny introns and harboring only one gene; (b) genomic comparisons between E. aediculatus and other reported spirotrichs indicate that average GC content and genome fragmentation levels exhibit interspecific variation, and chromosome breaking sites (CBSs) might be lost during evolution, resulting in the increase of multi-gene nanochromosome; (c) gene families associated with chitin metabolism and FoxO signaling pathway are expanded in E. aediculatus, suggesting their potential roles in environment adaptation and survival strategies of E. aediculatus; and (d) a programmed ribosomal frameshift (PRF) with a conservative motif 5'-AAATAR-3' tends to occur in longer genes with more exons, and PRF genes play an important role in many cellular regulation processes. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-023-00175-0.
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Affiliation(s)
- Didi Jin
- Laboratory of Protozoological Biodiversity and Evolution in Wetland, College of Life Sciences, Shaanxi Normal University, Xi’an, 710119 China
| | - Chao Li
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Xiao Chen
- Laboratory of Marine Protozoan Biodiversity and Evolution, Marine College, Shandong University, Weihai, 264209 China
| | - Adam Byerly
- Department of Computer Science and Information Systems, Bradley University, Peoria, 61625 USA
| | - Naomi A. Stover
- Department of Biology, Bradley University, Peoria, 61625 USA
| | - Tengteng Zhang
- Laboratory of Protozoological Biodiversity and Evolution in Wetland, College of Life Sciences, Shaanxi Normal University, Xi’an, 710119 China
| | - Chen Shao
- Laboratory of Protozoological Biodiversity and Evolution in Wetland, College of Life Sciences, Shaanxi Normal University, Xi’an, 710119 China
| | - Yurui Wang
- Laboratory of Protozoological Biodiversity and Evolution in Wetland, College of Life Sciences, Shaanxi Normal University, Xi’an, 710119 China
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4
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Yang J, Wang Z, Wang C, Tang D, Zang Z, Stover NA, Chen X, Li L. Single-cell transcriptome reveals cell division-regulated hub genes in the unicellular eukaryote Paramecium. Eur J Protistol 2023; 89:125978. [PMID: 37080141 DOI: 10.1016/j.ejop.2023.125978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/20/2023] [Accepted: 04/03/2023] [Indexed: 04/22/2023]
Abstract
The transition from growth to division during the cell cycle encompasses numerous conserved processes such as large-scale DNA replication and protein synthesis. In ciliate cells, asexual cell division is accompanied by additional cellular changes including amitotic nuclear division, extensive ciliogenesis, and trichocyst replication. However, the molecular mechanisms underlying these processes remain elusive. In this study, we present single-cell gene expression profiles of Paramecium cf. multimicronucleatum cells undergoing cell division. Our results reveal that the most up-regulated genes in dividing cells compared to growing cells are associated with 1) cell cycle signaling pathways including transcription, DNA replication, chromosome segregation and protein degradation; 2) microtubule proteins and tubulin glycylases which are essential for ciliogenesis, nuclei separation and structural differentiation signaling; and 3) trichocyst matrix proteins involved in trichocyst synthesis and reproduction. Furthermore, weighted gene co-expression network analysis identified hub genes that may play crucial roles during cell division. Our findings provide insights into cell cycle regulators, microtubules and trichocyst matrix proteins that may exert influence on this process in ciliates.
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Affiliation(s)
- Juan Yang
- Laboratory of Marine Protozoan Biodiversity & Evolution, Marine College, Shandong University, Weihai 264209, China
| | - Zhenyuan Wang
- Laboratory of Marine Protozoan Biodiversity & Evolution, Marine College, Shandong University, Weihai 264209, China
| | - Chundi Wang
- Laboratory of Marine Protozoan Biodiversity & Evolution, Marine College, Shandong University, Weihai 264209, China
| | - Danxu Tang
- Laboratory of Marine Protozoan Biodiversity & Evolution, Marine College, Shandong University, Weihai 264209, China
| | - Zihan Zang
- Laboratory of Marine Protozoan Biodiversity & Evolution, Marine College, Shandong University, Weihai 264209, China
| | - Naomi A Stover
- Department of Biology, Bradley University, Peoria 61625, USA
| | - Xiao Chen
- Laboratory of Marine Protozoan Biodiversity & Evolution, Marine College, Shandong University, Weihai 264209, China; Suzhou Research Institute, Shandong University, Suzhou 215123, China.
| | - Lifang Li
- Laboratory of Marine Protozoan Biodiversity & Evolution, Marine College, Shandong University, Weihai 264209, China.
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5
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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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6
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Wei F, Pan B, Diao J, Wang Y, Sheng Y, Gao S. The micronuclear histone H3 clipping in the unicellular eukaryote Tetrahymena thermophila. MARINE LIFE SCIENCE & TECHNOLOGY 2022; 4:584-594. [PMID: 37078088 PMCID: PMC10077241 DOI: 10.1007/s42995-022-00151-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 10/07/2022] [Indexed: 05/02/2023]
Abstract
Clipping of the histone H3 N-terminal tail has been implicated in multiple fundamental biological processes for a growing list of eukaryotes. H3 clipping, serving as an irreversible process to permanently remove some post-translational modifications (PTMs), may lead to noticeable changes in chromatin dynamics or gene expression. The eukaryotic model organism Tetrahymena thermophila is among the first few eukaryotes that exhibits H3 clipping activity, wherein the first six amino acids of H3 are cleaved off during vegetative growth. Clipping only occurs in the transcriptionally silent micronucleus of the binucleated T. thermophila, thus offering a unique opportunity to reveal the role of H3 clipping in epigenetic regulation. However, the physiological functions of the truncated H3 and its protease(s) for clipping remain elusive. Here, we review the major findings of H3 clipping in T. thermophila and highlight its association with histone modifications and cell cycle regulation. We also summarize the functions and mechanisms of H3 clipping in other eukaryotes, focusing on the high diversity in terms of protease families and cleavage sites. Finally, we predict several protease candidates in T. thermophila and provide insights for future studies. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-022-00151-0.
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Affiliation(s)
- Fan Wei
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 China
| | - Bo Pan
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 China
| | - Jinghan Diao
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 China
| | - Yuanyuan Wang
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 China
| | - Yalan Sheng
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Shan Gao
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 China
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7
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Wang Z, Chi Y, Li T, Song W, Wang Y, Wu T, Zhang G, Liu Y, Ma H, Song W, Al-Rasheid KAS, Warren A, Lu B. Biodiversity of freshwater ciliates (Protista, Ciliophora) in the Lake Weishan Wetland, China: the state of the art. MARINE LIFE SCIENCE & TECHNOLOGY 2022; 4:429-451. [PMID: 37078082 PMCID: PMC10077249 DOI: 10.1007/s42995-022-00154-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 10/20/2022] [Indexed: 05/02/2023]
Abstract
Ciliates are core components of the structure of and function of aquatic microbial food webs. They play an essential role in the energy flow and material circulation within aquatic ecosystems. However, studies on the taxonomy and biodiversity of freshwater ciliates, especially those in wetlands in China are limited. To address this issue, a project to investigate the freshwater ciliates of the Lake Weishan Wetland, Shandong Province, commenced in 2019. Here, we summarize our findings to date on the diversity of ciliates. A total of 187 ciliate species have been found, 94 of which are identified to species-level, 87 to genus-level, and six to family-level. These species show a high morphological diversity and represent five classes, i.e., Heterotrichea, Litostomatea, Prostomatea, Oligohymenophorea, and Spirotrichea. The largest number of species documented are oligohymenophoreans. A comprehensive database of these ciliates, including morphological data, gene sequences, microscope slide specimens and a DNA bank, has been established. In the present study, we provide an annotated checklist of retrieved ciliates as well as information on the sequences of published species. Most of these species are recorded in China for the first time and more than 20% are tentatively identified as new to science. Additionally, an investigation of environmental DNA revealed that the ciliate species diversity in Lake Weishan Wetland is higher than previously supposed. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-022-00154-x.
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Affiliation(s)
- Zhe Wang
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Marine College, Shandong University, Weihai, 264209 China
| | - Yong Chi
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Tao Li
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Wenya Song
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Yunfeng Wang
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Tong Wu
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Gongaote Zhang
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Yujie Liu
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Honggang Ma
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Weibo Song
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Marine College, Shandong University, Weihai, 264209 China
- Laoshan Laboratory, Qingdao, 266237 China
| | | | - Alan Warren
- Department of Life Sciences, Natural History Museum, London, SW7 5BD UK
| | - Borong Lu
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
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8
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Tian M, Cai X, Liu Y, Liucong M, Howard-Till R. A practical reference for studying meiosis in the model ciliate Tetrahymena thermophila. MARINE LIFE SCIENCE & TECHNOLOGY 2022; 4:595-608. [PMID: 37078080 PMCID: PMC10077211 DOI: 10.1007/s42995-022-00149-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 09/28/2022] [Indexed: 05/03/2023]
Abstract
Meiosis is a critical cell division program that produces haploid gametes for sexual reproduction. Abnormalities in meiosis are often causes of infertility and birth defects (e.g., Down syndrome). Most organisms use a highly specialized zipper-like protein complex, the synaptonemal complex (SC), to guide and stabilize pairing of homologous chromosomes in meiosis. Although the SC is critical for meiosis in many eukaryotes, there are organisms that perform meiosis without a functional SC. However, such SC-less meiosis is poorly characterized. To understand the features of SC-less meiosis and its adaptive significance, the ciliated protozoan Tetrahymena was selected as a model. Meiosis research in Tetrahymena has revealed intriguing aspects of the regulatory programs utilized in its SC-less meiosis, yet additional efforts are needed for obtaining an in-depth comprehension of mechanisms that are associated with the absence of SC. Here, aiming at promoting a wider application of Tetrahymena for meiosis research, we introduce basic concepts and core techniques for studying meiosis in Tetrahymena and then suggest future directions for expanding the current Tetrahymena meiosis research toolbox. These methodologies could be adopted for dissecting meiosis in poorly characterized ciliates that might reveal novel features. Such data will hopefully provide insights into the function of the SC and the evolution of meiosis from a unique perspective. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-022-00149-8.
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Affiliation(s)
- Miao Tian
- 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, 266237 China
- Institute of Human Genetics, CNRS, University of Montpellier, 34090 Montpellier, France
| | - Xia Cai
- 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, 266237 China
| | - Yujie 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, 266237 China
| | - Mingmei Liucong
- 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, 266237 China
| | - Rachel Howard-Till
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA USA
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9
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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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10
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Zheng W, Dou H, Li C, Al-Farraj SA, Byerly A, Stover NA, Song W, Chen X, Li L. Comparative Genome Analysis Reveals Cis-Regulatory Elements on Gene-Sized Chromosomes of Ciliated Protists. Front Microbiol 2022; 13:775646. [PMID: 35265055 PMCID: PMC8899921 DOI: 10.3389/fmicb.2022.775646] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 01/10/2022] [Indexed: 11/13/2022] Open
Abstract
Gene-sized chromosomes are a distinct feature of the macronuclear genome in ciliated protists known as spirotrichs. These nanochromosomes are often only several kilobase pairs long and contain a coding region for a single gene. However, the ways in which transcription is regulated on nanochromosomes is still largely unknown. Here, we generated macronuclear genome assemblies for two species of Pseudokeronopsis ciliates to better understand transcription regulation on gene-sized chromosomes. We searched within the short subtelomeric regions for potential cis-regulatory elements and identified distinct AT-rich sequences conserved in both species, at both the 5’ and 3’ end of each gene. We further acquired transcriptomic data for these species, which showed the 5’ cis-regulatory element is associated with active gene expression. Gene family evolution analysis suggests nanochromosomes in spirotrichs may originated approximately 900 million years ago. Together our comparative genomic analyses reveal novel insights into the biological roles of cis-regulatory elements on gene-sized chromosomes.
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Affiliation(s)
- Weibo Zheng
- Laboratory of Marine Protozoan Biodiversity and Evolution, Marine College, Shandong University, Weihai, China.,School of Life Sciences, Ludong University, Yantai, China.,Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Huan Dou
- Laboratory of Marine Protozoan Biodiversity and Evolution, Marine College, Shandong University, Weihai, China
| | - Chao Li
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Saleh A Al-Farraj
- Zoology Department, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Adam Byerly
- Department of Computer Science, Bradley University, Peoria, IL, United States
| | - Naomi A Stover
- Department of Biology, Bradley University, Peoria, IL, United States
| | - Weibo Song
- Laboratory of Marine Protozoan Biodiversity and Evolution, Marine College, Shandong University, Weihai, China.,Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Xiao Chen
- Laboratory of Marine Protozoan Biodiversity and Evolution, Marine College, Shandong University, Weihai, China
| | - Lifang Li
- Laboratory of Marine Protozoan Biodiversity and Evolution, Marine College, Shandong University, Weihai, China
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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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