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Lyu L, Zhang X, Gao Y, Zhang T, Fu J, Stover NA, Gao F. From germline genome to highly fragmented somatic genome: genome-wide DNA rearrangement during the sexual process in ciliated protists. MARINE LIFE SCIENCE & TECHNOLOGY 2024; 6:31-49. [PMID: 38433968 PMCID: PMC10901763 DOI: 10.1007/s42995-023-00213-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 11/27/2023] [Indexed: 03/05/2024]
Abstract
Genomes are incredibly dynamic within diverse eukaryotes and programmed genome rearrangements (PGR) play important roles in generating genomic diversity. However, genomes and chromosomes in metazoans are usually large in size which prevents our understanding of the origin and evolution of PGR. To expand our knowledge of genomic diversity and the evolutionary origin of complex genome rearrangements, we focus on ciliated protists (ciliates). Ciliates are single-celled eukaryotes with highly fragmented somatic chromosomes and massively scrambled germline genomes. PGR in ciliates occurs extensively by removing massive amounts of repetitive and selfish DNA elements found in the silent germline genome during development of the somatic genome. We report the partial germline genomes of two spirotrich ciliate species, namely Strombidium cf. sulcatum and Halteria grandinella, along with the most compact and highly fragmented somatic genome for S. cf. sulcatum. We provide the first insights into the genome rearrangements of these two species and compare these features with those of other ciliates. Our analyses reveal: (1) DNA sequence loss through evolution and during PGR in S. cf. sulcatum has combined to produce the most compact and efficient nanochromosomes observed to date; (2) the compact, transcriptome-like somatic genome in both species results from extensive removal of a relatively large number of shorter germline-specific DNA sequences; (3) long chromosome breakage site motifs are duplicated and retained in the somatic genome, revealing a complex model of chromosome fragmentation in spirotrichs; (4) gene scrambling and alternative processing are found throughout the core spirotrichs, offering unique opportunities to increase genetic diversity and regulation in this group. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-023-00213-x.
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Affiliation(s)
- Liping Lyu
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education), and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Xue Zhang
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education), and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Yunyi Gao
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education), and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Tengteng Zhang
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education), and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Jinyu Fu
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education), and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Naomi A. Stover
- Department of Biology, Bradley University, Peoria, IL 61625 USA
| | - Feng Gao
- Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education), and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laoshan Laboratory, Qingdao, 266237 China
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2
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Su H, Xu J, Li J, Yi Z. Four ciliate-specific expansion events occurred during actin gene family evolution of eukaryotes. Mol Phylogenet Evol 2023; 184:107789. [PMID: 37105243 DOI: 10.1016/j.ympev.2023.107789] [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: 01/20/2023] [Revised: 03/21/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023]
Abstract
Actin gene family is a divergent and ancient eukaryotic cellular cytoskeletal gene family, and participates in many essential cellular processes. Ciliated protists offer us an excellent opportunity to investigate gene family evolution, since their gene families evolved faster in ciliates than in other eukaryotes. Nonetheless, actin gene family is well studied in few model ciliate species but little is known about its evolutionary patterns in ciliates. Here, we analyzed the evolutionary pattern of eukaryotic actin gene family based on genomes/transcriptomes of 36 species covering ten ciliate classes, as well as those of nine non-ciliate eukaryotic species. Results showed: (1) Except for conventional actins and actin-related proteins (Arps) shared by various eukaryotes, at least four ciliate-specific subfamilies occurred during evolution of actin gene family. Expansions of Act2 and ArpC were supposed to have happen in the ciliate common ancestor, while expansions of ActI and ActII may have occurred in the ancestor of Armophorea, Muranotrichea, and Spirotrichea. (2) The number of actin isoforms varied greatly among ciliate species. Environmental adaptability, whole genome duplication (WGD) or segmental duplication events, distinct spatial and temporal patterns of expression might play driving forces for the increasement of isoform numbers. (3) The 'birth and death' model of evolution could explain the evolution of actin gene family in ciliates. And actin genes have been generally under strong negative selection to maintain protein structures and physiological functions. Collectively, we provided meaningful information for understanding the evolution of eukaryotic actin gene family.
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Affiliation(s)
- Hua Su
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Jiahui Xu
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Jia Li
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Zhenzhen Yi
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Science, South China Normal University, Guangzhou 510631, China.
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3
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Dong J, Liu Y, Ma J, Ma H, Stoeck T, Fan X. Ultrastructure of Diophrys appendiculata and new systematic consideration of the euplotid family Uronychiidae (Protista, Ciliophora). MARINE LIFE SCIENCE & TECHNOLOGY 2022; 4:551-568. [PMID: 37078077 PMCID: PMC10077282 DOI: 10.1007/s42995-022-00153-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 10/13/2022] [Indexed: 05/03/2023]
Abstract
The ultrastructure of ciliates carries important cytological, taxonomical, and evolutionary signals for these single-celled eukaryotic organisms. However, little ultrastructural data have been accumulated for most ciliate groups with systematic problems. In the present work, a well-known marine uronychiid, Diophrys appendiculata, was investigated using electron microscopy and a comparison with, and a discussion considering, phylogenetic analyses were made. The new findings primarily show that: (i) this species lacks the typical alveolar plate, bears cortical ampule-like extrusomes, and has microtubular triads in the dorsal pellicle, and thus exhibits some ultrastructural features in common with most of its previously studied congeners; (ii) each adoral membranelle before the level of frontal cirrus II/2 contains three rows of kinetosomes and each membranelle after the level of frontal cirrus II/2 contains four rows, which might be related with morphogenesis and could be considered as a distinctive character of Diophrys; (iii) some structural details of the buccal field, such as the extra-pellicular fibrils, pellicle, pharyngeal disks and microtubular sheet, were documented. In addition, based on the ultrastructural comparison of representatives, we discuss the differentiation between the subfamilies Diophryinae and Uronychiinae. A hypothetical systematic relationship of members in the order Euplotida based on a wide range of data is also provided.
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Affiliation(s)
- Jingyi Dong
- School of Life Sciences, East China Normal University, Shanghai, 200241 China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laoshan Laboratory, Qingdao, 266237 China
| | - Yujie Liu
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Jiyang Ma
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Honggang Ma
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
| | - Thorsten Stoeck
- Ecology Group, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Xinpeng Fan
- School of Life Sciences, East China Normal University, Shanghai, 200241 China
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4
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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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Ye T, Jiang Y, Chen S, Xu Y, Li L, Shin MK, Chen X. The widely reported but poorly studied ciliate family Folliculinidae (Protozoa, Ciliophora, Heterotrichea): a revision with notes on its taxonomy, morphology and phylogenetic relationships. MARINE LIFE SCIENCE & TECHNOLOGY 2022; 4:471-492. [PMID: 37078084 PMCID: PMC10077228 DOI: 10.1007/s42995-022-00152-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 10/17/2022] [Indexed: 05/03/2023]
Abstract
Ciliates of the heterotrich family Folliculinidae are widespread in various habitats and are distinguished by their transparent loricae of various shapes, conspicuous peristomial lobes, and dimorphic life cycles. They usually attach firmly to the surface of substrates, feed on bacteria and microalgae, and play a significant role in energy flow and material cycling in the microbial food web. However, little is known regarding their biodiversity and systematics. In this work, we establish the terminology of the family Folliculinidae and select six crucial features for genus recognition. Based on previous studies, we revise the classification of Folliculinidae, supply improved diagnoses for each of the 33 folliculinid genera, and provide a key to their identification. Moreover, phylogenetic analyses based on small subunit ribosomal DNA (SSU rDNA) sequences revealed that the family is monophyletic and comprises two subclades (subclades I II) which can be identified by the flexibility of their peristomial lobes and the sculpturing of their necks. Furthermore, we investigate the evolutionary relationships of folliculinids using the six chosen generic features. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-022-00152-z.
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Affiliation(s)
- Tingting Ye
- School of Marine Sciences, Ningbo University, Ningbo, 315800 China
- Laboratory of Marine Protozoan Biodiversity and Evolution, Marine College, Shandong University, Weihai, 264209 China
| | - Yaohan Jiang
- Institute of Evolution and Marine Biodiversity, and College of Fisheries, Ocean University of China, Qingdao, 266003 China
| | - Shuchang Chen
- School of Marine Sciences, Ningbo University, Ningbo, 315800 China
| | - Yixiang Xu
- School of Marine Sciences, Ningbo University, Ningbo, 315800 China
| | - Lifang Li
- Laboratory of Marine Protozoan Biodiversity and Evolution, Marine College, Shandong University, Weihai, 264209 China
| | - Mann Kyoon Shin
- Department of Biological Sciences, University of Ulsan, Ulsan, 44610 South Korea
| | - Xiangrui Chen
- School of Marine Sciences, Ningbo University, Ningbo, 315800 China
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6
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Zhang X, Lu X, Chi Y, Jiang Y, Wang C, Al-Farraj SA, Vallesi A, Gao F. Timing and characteristics of nuclear events during conjugation and genomic exclusion in Paramecium multimicronucleatum. MARINE LIFE SCIENCE & TECHNOLOGY 2022; 4:317-328. [PMID: 37073165 PMCID: PMC10077201 DOI: 10.1007/s42995-022-00137-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 06/01/2022] [Indexed: 05/03/2023]
Abstract
Ciliated protists are ideal material for studying the origin and evolution of sex, because of their nuclear dimorphism (containing both germline micronucleus and somatic macronucleus in the same cytoplasm), special sexual processes (conjugation and autogamy), and high diversity of mating-type systems. However, the study of sexual process is limited to only a few species, due to the difficulties in inducing or observing conjugation. In the present study, we investigate the conjugation process in Paramecium multimicronucleatum: (1) of the three prezygotic divisions, all micronuclei undergo the first two divisions (meiosis I, II), while a variable number of nuclei undergo the third division (mitosis); (2) the synkaryon divides three times after fertilization, giving rise to eight products that differentiate into four macronuclear anlagen and four micronuclei; (3) cells restore the vegetative stage after two successive cell fissions during which the macronuclear anlagen are distributed into daughter cells without division, while micronuclei divide mitotically; (4) the parental macronucleus begins to fragment following the first meiotic division and finally degenerates completely; (5) the entire process takes about 110 h, of which about 85 h are required for macronuclear development. In addition, we describe for the first time the process of genomic exclusion occurring between amicronucleate and micronucleate cells of P. multimicronucleatum, during which the micronucleate cell contributes a pronucleus to the amicronucleate cell, resulting in both exconjugants being homozygotes. These results provide new insights into the diversity of sexual processes and lay an important cytological basis for future in-depth studies of mating systems in ciliates.
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Affiliation(s)
- Xue Zhang
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Key Laboratory of Mariculture (OUC), Ministry of Education, Qingdao, 266003 China
| | - Xiaoteng Lu
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen, 518172 China
| | - Yong Chi
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Key Laboratory of Mariculture (OUC), Ministry of Education, Qingdao, 266003 China
| | - Yaohan Jiang
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Key Laboratory of Mariculture (OUC), Ministry of Education, Qingdao, 266003 China
| | - Chundi Wang
- Laboratory of Marine Protozoan Biodiversity and Evolution, Shandong University, Weihai, 264209 China
| | - Saleh A. Al-Farraj
- Zoology Department, College of Science, King Saud University, Riyadh, 11451 Saudi Arabia
| | - Adriana Vallesi
- Laboratory of Eukaryotic Microbiology and Animal Biology, University of Camerino, 62032 Camerino, Italy
| | - Feng Gao
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Key Laboratory of Mariculture (OUC), Ministry of Education, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237 China
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7
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Zhang B, Hou L, Qi H, Hou L, Zhang T, Zhao F, Miao M. An extremely streamlined macronuclear genome in the free-living protozoan Fabrea salina. Mol Biol Evol 2022; 39:6553891. [PMID: 35325184 PMCID: PMC9004412 DOI: 10.1093/molbev/msac062] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Ciliated protists are among the oldest unicellular organisms with a heterotrophic lifestyle and share a common ancestor with Plantae. Unlike any other eukaryotes, there are two distinct nuclei in ciliates with separate germline and somatic cell functions. Here, we assembled a near-complete macronuclear genome of Fabrea salina, which belongs to one of the oldest clades of ciliates. Its extremely minimized genome (18.35 Mb) is the smallest among all free-living heterotrophic eukaryotes and exhibits typical streamlined genomic features, including high gene density, tiny introns, and shrinkage of gene paralogs. Gene families involved in hypersaline stress resistance, DNA replication proteins, and mitochondrial biogenesis are expanded, and the accumulation of phosphatidic acid may play an important role in resistance to high osmotic pressure. We further investigated the morphological and transcriptomic changes in the macronucleus during sexual reproduction and highlighted the potential contribution of macronuclear residuals to this process. We believe that the minimized genome generated in this study provides novel insights into the genome streamlining theory and will be an ideal model to study the evolution of eukaryotic heterotrophs.
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Affiliation(s)
- Bing Zhang
- University of Chinese Academy of Sciences, Beijing 100049, China.,Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing 100101, China
| | - Lina Hou
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongli Qi
- Tianjin Key Laboratory of Aqua-ecology and Aquaculture, Fisheries College, Tianjin Agricultural University, Tianjin 300392, China
| | - Lingling Hou
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tiancheng Zhang
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fangqing Zhao
- University of Chinese Academy of Sciences, Beijing 100049, China.,Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing 100101, China
| | - Miao Miao
- University of Chinese Academy of Sciences, Beijing 100049, China
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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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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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11
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Lian C, Wang Y, Jiang J, Yuan Q, Al-Farraj SA, El-Serehy HA, Song W, Stoeck T, Shao C. Systematic positions and taxonomy of two new ciliates found in China: Euplotes tuffraui sp. nov. and E. shii sp. nov. (Alveolata, Ciliophora, Euplotida). SYST BIODIVERS 2021. [DOI: 10.1080/14772000.2020.1865472] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Chunyu Lian
- Laboratory of Protozoological Biodiversity and Evolution in Wetland, College of Life Sciences, Shaanxi Normal University, Xi’an, 710119, China
- Institute of Evolution & Marine Biodiversity, and College of Fisheries, Ocean University of China, Qingdao, 266003, China
- Department of Ecology, University of Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Yurui Wang
- Laboratory of Protozoological Biodiversity and Evolution in Wetland, College of Life Sciences, Shaanxi Normal University, Xi’an, 710119, China
| | - Jiamei Jiang
- Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Shanghai Ocean University, Shanghai, 201306, China
| | - Qingxiang Yuan
- Institute of Evolution & Marine Biodiversity, and College of Fisheries, Ocean University of China, Qingdao, 266003, China
| | - Saleh A. Al-Farraj
- Zoology Department, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Hamed A. El-Serehy
- Zoology Department, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Weibo Song
- Institute of Evolution & Marine Biodiversity, and College of Fisheries, Ocean University of China, Qingdao, 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China
| | - Thorsten Stoeck
- Department of Ecology, University of Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Chen Shao
- Laboratory of Protozoological Biodiversity and Evolution in Wetland, College of Life Sciences, Shaanxi Normal University, Xi’an, 710119, China
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12
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Tang D, Wang X, Dong J, Li Y, Gao F, Xie H, Zhao C. Morpholino-Mediated Knockdown of Ciliary Genes in Euplotes vannus, a Novel Marine Ciliated Model Organism. Front Microbiol 2020; 11:549781. [PMID: 33193130 PMCID: PMC7604394 DOI: 10.3389/fmicb.2020.549781] [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: 04/09/2020] [Accepted: 09/22/2020] [Indexed: 12/28/2022] Open
Abstract
Cilia are highly conserved organelles present in almost all types of eukaryotic cells, and defects in cilia structure and/or function are related to many human genetic disorders. Single-celled ciliated protists, which possess diverse types of cilia, are remarkable model organisms for studying cilia structures and functions. Euplotes vannus is a representative ciliate with many intriguing features; for example, it possesses extensively fragmented somatic genomes and a high frequency of + 1 programmed ribosomal frameshifting. However, the molecular mechanisms underlying these remarkable traits remain largely unknown, mainly due to the lack of efficient genetic manipulation tools. Here, we describe the first application of a morpholino-based strategy to knockdown gene expression in E. vannus. Through interfering with the function of two ciliary genes, ZMYND10 and C21ORF59, we showed that these two genes are essential for the ciliary motility and proliferation of E. vannus cells. Strikingly, both ZMYND10- and C21ORF59-knockdown cells developed shorter cilia in the ventral cirri, a special type of ciliary tuft, suggesting a novel role for these genes in the regulation of cilia length. Our data provide a new method to explore gene function in E. vannus, which may help us to understand the functions of evolutionarily conserved cilia-related genes as well as other biological processes in this intriguing model.
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Affiliation(s)
- Danxu Tang
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Xiaoyu Wang
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Jingyi Dong
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Yuan Li
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Feng Gao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Haibo Xie
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Chengtian Zhao
- Institute of Evolution & 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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13
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New contributions to the phylogeny of the ciliate class Heterotrichea (Protista, Ciliophora): analyses at family-genus level and new evolutionary hypotheses. SCIENCE CHINA-LIFE SCIENCES 2020; 64:606-620. [PMID: 33068287 DOI: 10.1007/s11427-020-1817-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/06/2020] [Indexed: 01/15/2023]
Abstract
Heterotrichous ciliates play an important role in aquatic ecosystem energy flow processes and many are model organisms for research in cytology, regenerative biology, and toxicology. In the present study, we combine both morphological and molecular data to infer phylogenetic relationships at family-genus level and propose new evolutionary hypotheses for the class Heterotrichea. The main results include: (1) 96 new ribosomal DNA sequences from 36 populations, representing eight families and 13 genera, including three poorly annotated genera, Folliculinopsis, Ampullofolliculina and Linostomella; (2) the earliest-branching families are Spirostomidae in single-gene trees and Peritromidae in the concatenated tree, but the family Peritromidae probably represents the basal lineage based on its possession of many "primitive" morphological characters; (3) some findings in molecular trees are not supported by morphological evidence, such as the family Blepharismidae is one of the most recent branches and the relationship between Fabreidae and Folliculinidae is very close; (4) the systematic positions of Condylostomatidae, Climacostomidae, and Gruberiidae remain uncertain based either on morphological or molecular data; and (5) the monophyly of each genus included in the present study is supported by the molecular phylogenetic trees, except for Blepharisma in the SSU rDNA tree and Folliculina in the ITS1-5.8S-ITS2 tree.
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14
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Ricci F, Luporini P, Alimenti C, Vallesi A. Functional chimeric genes in ciliates: An instructive case from Euplotes raikovi. Gene 2020; 767:145186. [PMID: 32998045 DOI: 10.1016/j.gene.2020.145186] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 09/09/2020] [Accepted: 09/23/2020] [Indexed: 11/29/2022]
Abstract
In ciliates, with every sexual event the transcriptionally active genes of the sub-chromosomic somatic genome that resides in the cell macronucleus are lost. They are de novo assembled starting from 'Macronuclear Destined Sequences' that arise from the fragmentation of transcriptionally silent DNA sequences of the germline chromosomic genome enclosed in the cell micronucleus. The RNA-mediated epigenetic mechanism that drives the assembly of these sequences is subject to errors which result in the formation of chimeric genes. Studying a gene family that in Euplotes raikovi controls the synthesis of protein signal pheromones responsible for a self/not-self recognition mechanism, we identified the chimeric structure of an 851-bp macronuclear gene previously known to specify soluble and membrane-bound pheromone molecules through an intron-splicing mechanism. This chimeric gene, designated mac-er-1*, conserved the native pheromone-gene structure throughout its coding and 3' regions. Instead, its 5' region is completely unrelated to the pheromone gene structure at the level of a 360-bp sequence, which derives from the assembly with a MDS destined to compound a 2417-bp gene encoding a 696-amino acid protein with unknown function. This mac-er-1* gene characterization provides further evidence that ciliates rely on functional chimeric genes that originate in non-programmed phenomena of somatic MDS recombination to increase the species genetic variability independently of gene reshuffling phenomena of the germline genome.
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Affiliation(s)
- Francesca Ricci
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino 62032, Italy
| | - Pierangelo Luporini
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino 62032, Italy
| | - Claudio Alimenti
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino 62032, Italy
| | - Adriana Vallesi
- Laboratory of Eukaryotic Microbiology and Animal Biology, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino 62032, Italy.
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