1
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Huang Y, Lee YCG. Blessing or curse: how the epigenetic resolution of host-transposable element conflicts shapes their evolutionary dynamics. Proc Biol Sci 2024; 291:20232775. [PMID: 38593848 PMCID: PMC11003778 DOI: 10.1098/rspb.2023.2775] [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: 12/08/2023] [Accepted: 03/01/2024] [Indexed: 04/11/2024] Open
Abstract
Transposable elements (TEs) are selfish genetic elements whose antagonistic interactions with hosts represent a common genetic conflict in eukaryotes. To resolve this conflict, hosts have widely adopted epigenetic silencing that deposits repressive marks at TEs. However, this mechanism is imperfect and fails to fully halt TE replication. Furthermore, TE epigenetic silencing can inadvertently spread repressive marks to adjacent functional sequences, a phenomenon considered a 'curse' of this conflict resolution. Here, we used forward simulations to explore how TE epigenetic silencing and its harmful side effects shape the evolutionary dynamics of TEs and their hosts. Our findings reveal that epigenetic silencing allows TEs and their hosts to stably coexist under a wide range of conditions, because the underlying molecular mechanisms give rise to copy-number dependency of the strength of TE silencing. Interestingly, contrary to intuitive expectations that TE epigenetic silencing should evolve to be as strong as possible, we found a selective benefit for modifier alleles that weaken TE silencing under biologically feasible conditions. These results reveal that the dual nature of TE epigenetic silencing, with both positive and negative effects, complicates its evolutionary trajectory and makes it challenging to determine whether TE epigenetic silencing is a 'blessing' or a 'curse'.
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Affiliation(s)
- Yuheng Huang
- Department of Ecology and Evolutionary Biology, University of California, Irvine, USA
| | - Yuh Chwen G. Lee
- Department of Ecology and Evolutionary Biology, University of California, Irvine, USA
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2
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Huang S, Yoshitake K, Kinoshita S, Asakawa S. Transcriptional landscape of small non-coding RNAs reveals diversity of categories and functions in molluscs. RNA Biol 2024; 21:1-13. [PMID: 38693614 PMCID: PMC11067994 DOI: 10.1080/15476286.2024.2348893] [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] [Accepted: 12/07/2022] [Indexed: 05/03/2024] Open
Abstract
Small non-coding RNAs (sncRNAs) are non-coding RNA molecules that play various roles in metazoans. Among the sncRNAs, microRNAs (miRNAs) guide post-translational gene regulation during cellular development, proliferation, apoptosis, and differentiation, while PIWI-interacting RNAs (piRNAs) suppress transposon activity to safeguard the genome from detrimental insertion mutagenesis. While an increasing number of piRNAs are being identified in the soma and germlines of various organisms, they are scarcely reported in molluscs. To unravel the small RNA (sRNA) expression patterns and genomic function in molluscs, we generated a comprehensive sRNA dataset by sRNA sequencing (sRNA-seq) of eight mollusc species. Abundant miRNAs were identified and characterized in all investigated molluscs, and ubiquitous piRNAs were discovered in both somatic and gonadal tissues in six of the investigated molluscs, which are more closely associated with transposon silencing. Tens of piRNA clusters were also identified based on the genomic mapping results, which varied among different tissues and species. Our dataset serves as important reference data for future genomic and genetic studies on sRNAs in these molluscs and related species, especially in elucidating the ancestral state of piRNAs in bilaterians.
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Affiliation(s)
- Songqian Huang
- International Research Center for Marine Biosciences, Ministry of Science and Technology, College of Fisheries and Life Sciences, Shanghai Ocean University, Shanghai, China
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, College of Fisheries and Life Sciences, Shanghai Ocean University, Shanghai, China
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, College of Fisheries and Life Sciences, Shanghai Ocean University, Shanghai, China
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Science, The University of Tokyo, Tokyo, Japan
| | - Kazutoshi Yoshitake
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Science, The University of Tokyo, Tokyo, Japan
| | - Shigeharu Kinoshita
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Science, The University of Tokyo, Tokyo, Japan
| | - Shuichi Asakawa
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Science, The University of Tokyo, Tokyo, Japan
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3
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Wu Z, Yu X, Zhang S, He Y, Guo W. Novel roles of PIWI proteins and PIWI-interacting RNAs in human health and diseases. Cell Commun Signal 2023; 21:343. [PMID: 38031146 PMCID: PMC10685540 DOI: 10.1186/s12964-023-01368-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 10/26/2023] [Indexed: 12/01/2023] Open
Abstract
Non-coding RNA has aroused great research interest recently, they play a wide range of biological functions, such as regulating cell cycle, cell proliferation, and intracellular substance metabolism. Piwi-interacting RNAs (piRNAs) are emerging small non-coding RNAs that are 24-31 nucleotides in length. Previous studies on piRNAs were mainly limited to evaluating the binding to the PIWI protein family to play the biological role. However, recent studies have shed more lights on piRNA functions; aberrant piRNAs play unique roles in many human diseases, including diverse lethal cancers. Therefore, understanding the mechanism of piRNAs expression and the specific functional roles of piRNAs in human diseases is crucial for developing its clinical applications. Presently, research on piRNAs mainly focuses on their cancer-specific functions but lacks investigation of their expressions and epigenetic modifications. This review discusses piRNA's biogenesis and functional roles and the recent progress of functions of piRNA/PIWI protein complexes in human diseases. Video Abstract.
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Affiliation(s)
- Zeyu Wu
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
- Key Laboratory of Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation of Henan Province, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
- Open and Key Laboratory of Hepatobiliary & Pancreatic Surgery and Digestive Organ Transplantation at Henan Universities, Zhengzhou, 450052, China
- Henan Key Laboratory of Digestive Organ Transplantation, Zhengzhou, 450052, China
| | - Xiao Yu
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
- Key Laboratory of Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation of Henan Province, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
- Open and Key Laboratory of Hepatobiliary & Pancreatic Surgery and Digestive Organ Transplantation at Henan Universities, Zhengzhou, 450052, China
- Henan Key Laboratory of Digestive Organ Transplantation, Zhengzhou, 450052, China
| | - Shuijun Zhang
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
- Key Laboratory of Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation of Henan Province, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
- Open and Key Laboratory of Hepatobiliary & Pancreatic Surgery and Digestive Organ Transplantation at Henan Universities, Zhengzhou, 450052, China
- Henan Key Laboratory of Digestive Organ Transplantation, Zhengzhou, 450052, China
| | - Yuting He
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
- Key Laboratory of Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation of Henan Province, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
- Open and Key Laboratory of Hepatobiliary & Pancreatic Surgery and Digestive Organ Transplantation at Henan Universities, Zhengzhou, 450052, China.
- Henan Key Laboratory of Digestive Organ Transplantation, Zhengzhou, 450052, China.
| | - Wenzhi Guo
- Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
- Key Laboratory of Hepatobiliary and Pancreatic Surgery and Digestive Organ Transplantation of Henan Province, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
- Open and Key Laboratory of Hepatobiliary & Pancreatic Surgery and Digestive Organ Transplantation at Henan Universities, Zhengzhou, 450052, China.
- Henan Key Laboratory of Digestive Organ Transplantation, Zhengzhou, 450052, China.
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4
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Liu X, Zhang Y, Pu Y, Ma Y, Jiang L. Whole-genome identification of transposable elements reveals the equine repetitive element insertion polymorphism in Chinese horses. Anim Genet 2023; 54:144-154. [PMID: 36464985 DOI: 10.1111/age.13277] [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: 08/13/2022] [Revised: 10/29/2022] [Accepted: 11/14/2022] [Indexed: 12/12/2022]
Abstract
Transposable elements (TEs) are diverse, abundant, and complicated in genomes. They not only can drive the genome evolution process but can also act as special resources for adaptation. However, little is known about the evolutionary processes that shaped horses. In this work, 126 horse assemblages involved in most horse breeds in China were used to investigate the patterns of TE variation for the first time. By using RepeatMasker and melt software, we found that the horse-specific short interspersed repetitive elements family, equine repetitive elements (ERE1), exhibited polymorphisms in horse genomes. Phylogenetic analysis based on these ERE1 loci (minor allele frequency ≥0.05) revealed three major horse groups, namely, those in northern China, southern China, and Qinghai-Tibetan, which mirrors the result determined by SNPs to some extent. The present ERE1 family emerged ~0.26 to 1.77 Mya ago, with an activity peak at ~0.49 Mya, which matches the early stage of the horse lineage and decreases after the divergence of Equus caballus and Equus ferus przewalskii. To detect the functional ERE1(s) associated with adaptation, locus-specific branch length, genome-wide association study, and absolute allele frequency difference analyses were conducted and resulted in two common protein-coding genes annotated by candidate ERE1s. They were clustered into the vascular smooth muscle contraction (p = 0.01, EDNRA) and apelin signalling pathways (p = 0.02, NRF1). Notably, ERE1 insertion into the EDNRA gene showed a higher association with adaptation among southern China horses and other horses in 15 populations and 451 individuals (p = 4.55 e-8). Our results provide a comprehensive understanding of TE variations to analyse the phylogenetic relationships and traits relevant to adaptive evolution in horses.
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Affiliation(s)
- Xuexue Liu
- National Germplasm Centre of Domestic Animal Resources, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China.,Centre d'Anthropobiologie et de Génomique de Toulouse, Université Paul Sabatier, Toulouse, France
| | - Yanli Zhang
- National Germplasm Centre of Domestic Animal Resources, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China.,CAAS-ILRI Joint Laboratory on Livestock and Forage Genetic Resources, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Yabin Pu
- National Germplasm Centre of Domestic Animal Resources, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China.,CAAS-ILRI Joint Laboratory on Livestock and Forage Genetic Resources, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Yuehui Ma
- National Germplasm Centre of Domestic Animal Resources, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China.,CAAS-ILRI Joint Laboratory on Livestock and Forage Genetic Resources, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Lin Jiang
- National Germplasm Centre of Domestic Animal Resources, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China.,CAAS-ILRI Joint Laboratory on Livestock and Forage Genetic Resources, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
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5
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Wang J, Yuan L, Tang J, Liu J, Sun C, Itgen MW, Chen G, Sessions SK, Zhang G, Mueller RL. Transposable element and host silencing activity in gigantic genomes. Front Cell Dev Biol 2023; 11:1124374. [PMID: 36910142 PMCID: PMC9998948 DOI: 10.3389/fcell.2023.1124374] [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: 12/15/2022] [Accepted: 02/09/2023] [Indexed: 02/26/2023] Open
Abstract
Transposable elements (TEs) and the silencing machinery of their hosts are engaged in a germline arms-race dynamic that shapes TE accumulation and, therefore, genome size. In animal species with extremely large genomes (>10 Gb), TE accumulation has been pushed to the extreme, prompting the question of whether TE silencing also deviates from typical conditions. To address this question, we characterize TE silencing via two pathways-the piRNA pathway and KRAB-ZFP transcriptional repression-in the male and female gonads of Ranodon sibiricus, a salamander species with a ∼21 Gb genome. We quantify 1) genomic TE diversity, 2) TE expression, and 3) small RNA expression and find a significant relationship between the expression of piRNAs and TEs they target for silencing in both ovaries and testes. We also quantified TE silencing pathway gene expression in R. sibiricus and 14 other vertebrates with genome sizes ranging from 1 to 130 Gb and find no association between pathway expression and genome size. Taken together, our results reveal that the gigantic R. sibiricus genome includes at least 19 putatively active TE superfamilies, all of which are targeted by the piRNA pathway in proportion to their expression levels, suggesting comprehensive piRNA-mediated silencing. Testes have higher TE expression than ovaries, suggesting that they may contribute more to the species' high genomic TE load. We posit that apparently conflicting interpretations of TE silencing and genomic gigantism in the literature, as well as the absence of a correlation between TE silencing pathway gene expression and genome size, can be reconciled by considering whether the TE community or the host is currently "on the attack" in the arms race dynamic.
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Affiliation(s)
- Jie Wang
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan, China
| | - Liang Yuan
- School of Life Sciences, Xinjiang Normal University, Urumqi, China
| | - Jiaxing Tang
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan, China.,College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Jiongyu Liu
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan, China
| | - Cheng Sun
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Michael W Itgen
- Department of Biology, Colorado State University, Fort Collins, CO, United States
| | - Guiying Chen
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | | | - Guangpu Zhang
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan, China.,College of Life Sciences, Sichuan Normal University, Chengdu, China
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6
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Vandewege MW, Patt RN, Merriman DK, Ray DA, Hoffmann FG. The PIWI/piRNA response is relaxed in a rodent that lacks mobilizing transposable elements. RNA (NEW YORK, N.Y.) 2022; 28:609-621. [PMID: 35064043 PMCID: PMC8925971 DOI: 10.1261/rna.078862.121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
Transposable elements (TEs) are genomic parasites that can propagate throughout host genomes. Mammalian genomes are typically dominated by LINE retrotransposons and their associated SINEs, and germline mobilization is a challenge to genome integrity. There are defenses against TE proliferation and the PIWI/piRNA defense is among the most well understood. However, the PIWI/piRNA system has been investigated largely in animals with actively mobilizing TEs and it is unclear how the PIWI/piRNA system functions in the absence of mobilizing TEs. The 13-lined ground squirrel provides the opportunity to examine PIWI/piRNA and TE dynamics within the context of minimal, and possibly nonexistent, TE accumulation. To do so, we compared the PIWI/piRNA dynamics in squirrels to observations from the rabbit and mouse. Despite a lack of young insertions in squirrels, TEs were still actively transcribed at higher levels compared to mouse and rabbit. All three Piwi genes were not expressed, prior to P8 in squirrel testis, and there was little TE expression change with the onset of Piwi expression. We also demonstrated there was not a major expression change in the young squirrel LINE families in the transition from juvenile to adult testis in contrast to young mouse and rabbit LINE families. These observations lead us to conclude that PIWI suppression, was weaker for squirrel LINEs and SINEs and did not strongly reduce their transcription. We speculate that, although the PIWI/piRNA system is adaptable to novel TE threats, transcripts from TEs that are no longer threatening receive less attention from PIWI proteins.
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Affiliation(s)
- Michael W Vandewege
- Department of Biology, Eastern New Mexico University, Portales, New Mexico 88130, USA
| | - Roy N Patt
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, Texas 78245-0549, USA
| | - Dana K Merriman
- Department of Biology, University of Wisconsin Oshkosh, Oshkosh, Wisconsin 54901, USA
| | - David A Ray
- Department of Biological Sciences, Texas Tech University, Lubbock, Texas 79409, USA
| | - Federico G Hoffmann
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, Mississippi 39762, USA
- Institute of Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, Mississippi 39762, USA
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7
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Soares SC, Eler ES, E Silva CEF, da Silva MNF, Araújo NP, Svartman M, Feldberg E. LINE-1 and SINE-B1 mapping and genome diversification in Proechimys species (Rodentia: Echimyidae). Life Sci Alliance 2022; 5:5/6/e202101104. [PMID: 35304430 PMCID: PMC8932440 DOI: 10.26508/lsa.202101104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 02/25/2022] [Accepted: 02/28/2022] [Indexed: 11/24/2022] Open
Abstract
This study aimed to understand the impact of LINE-1 and SINE-B1 retroelements on the architecture and karyotypic diversification of five rodent species of the genus Proechimys from different regions of the Amazon. Karyotype comparisons were performed using fluorescent interspecific in situ hybridization. The L1 and B1 retroelements showed a non-random arrangement and a conserved pattern when the genomes of the five species of Proechimys were compared, including the two cytotypes of Proechimys guyannensis The signal homeology among the chromosomes and the degree of similarity among the formed clusters indicate rearrangements such as fusion/fission, and demonstrates that these retroelements can behave as derived characters shared in Proechimys The differentiated distribution and organization of these retroelements in the karyotypes and in the chromosomal fiber, respectively, may represent a strong indication of their role as generating sources of karyotypic diversity in the genus Proechimys and provide insights into the evolutionary relationships between taxa.
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Affiliation(s)
- Simone Cardoso Soares
- Pós-Graduação em Genética, Conservação e Biologia Evolutiva, Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil .,Laboratório de Genética Animal (LGA), Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil.,Universidade do Estado do Amazonas, Manaus, Brazil
| | - Eduardo Schmidt Eler
- Pós-Graduação em Genética, Conservação e Biologia Evolutiva, Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil
| | - Carlos Eduardo Faresin E Silva
- Pós-Graduação em Genética, Conservação e Biologia Evolutiva, Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil.,Laboratório de Genética Animal (LGA), Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil
| | | | - Naiara Pereira Araújo
- Departamento de Genética, Ecologia e Evolução, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.,Instituto Federal de Educação, Ciência e Tecnologia de Rondônia campus Jaru, Jaru, Brazil
| | - Marta Svartman
- Departamento de Genética, Ecologia e Evolução, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Eliana Feldberg
- Pós-Graduação em Genética, Conservação e Biologia Evolutiva, Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil.,Laboratório de Genética Animal (LGA), Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil
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8
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Suda K, Hayashi SR, Tamura K, Takamatsu N, Ito M. Activation of DNA Transposons and Evolution of piRNA Genes Through Interspecific Hybridization in Xenopus Frogs. Front Genet 2022; 13:766424. [PMID: 35173768 PMCID: PMC8841583 DOI: 10.3389/fgene.2022.766424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 01/13/2022] [Indexed: 01/28/2023] Open
Abstract
Interspecific hybridization between two closely related species sometimes resulted in a new species with allotetraploid genomes. Many clawed frog species belonging to the Xenopus genus have diverged from the allotetraploid ancestor created by the hybridization of two closely related species with the predicted L and S genomes. There are species-specific repeated sequences including transposable elements in each genome of organisms that reproduce sexually. To understand what happened on and after the hybridization of the two distinct systems consisting of repeated sequences and their corresponding piRNAs, we isolated small RNAs from ovaries and testes of three Xenopus species consisting of allotetraploid X. laevis and X. borealis and diploid X. tropicalis as controls. After a comprehensive sequencing and selection of piRNAs, comparison of their sequences showed that most piRNA sequences were different between the ovaries and testes in all three species. We compared piRNA and genome sequences and specified gene clusters for piRNA expression in each genome. The synteny and homology analyses showed many distinct piRNA clusters among the three species and even between the two L and/or S subgenomes, indicating that most clusters of the two allotetraploid species changed after hybridization. Moreover, evolutionary analysis showed that DNA transposons including Kolobok superfamily might get activated just after hybridization and then gradually inactivated. These findings suggest that some DNA transposons and their piRNAs might greatly influence allotetraploid genome evolution after hybridization.
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Affiliation(s)
| | | | | | | | - Michihiko Ito
- Department of Bioscience, School of Science, Kitasato University, Sagamihara, Japan
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9
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Ghosh B, Sarkar A, Mondal S, Bhattacharya N, Khatua S, Ghosh Z. piRNAQuest V.2: an updated resource for searching through the piRNAome of multiple species. RNA Biol 2021; 19:12-25. [PMID: 34965192 PMCID: PMC8786328 DOI: 10.1080/15476286.2021.2010960] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
PIWI interacting RNAs (piRNAs) have emerged as important gene regulators in recent times. Since the release of our first version of piRNAQuest in 2014, lots of novel piRNAs have been annotated in different species other than human, mouse and rat. Such new developments in piRNA research have led us to develop an updated database piRNAQuest V.2. It consists of 92,77,689 piRNA entries for 25 new species of different phylum along with human, mouse and rat. Besides providing primary piRNA features which include their genomic location, with further information on piRNAs overlapping with repeat elements, pseudogenes and syntenic regions, etc., the novel features of this version includes (i) density based cluster prediction, (ii) piRNA expression profile across various healthy and disease systems and (iii) piRNA target prediction. The concept of density-based piRNA cluster identification is robust as it does not consider parametric distribution in its model. The piRNA expression profile for 21 disease systems including cancer have been hosted in addition to 32 tissue specific piRNA expression profile for various species. Further, the piRNA target prediction section includes both predicted and curated piRNA targets within eight disease systems and developmental stages of mouse testis. Further, users can visualize the piRNA-target duplex structure and the ping-pong signature pattern for all the ping-pong piRNA partners in different species. Overall, piRNAQuest V.2 is an updated user-friendly database which will serve as a useful resource to survey, search and retrieve information on piRNAs for multiple species. This freely accessible database is available at http://dibresources.jcbose.ac.in/zhumur/pirnaquest2.
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Affiliation(s)
- Byapti Ghosh
- Division of Bioinformatics, Bose Institute, Kolkata, India
| | - Arijita Sarkar
- Division of Bioinformatics, Bose Institute, Kolkata, India.,Present Affiliation: Department of Orthopaedic Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Sudip Mondal
- Department of Computer Science and Engineering, University of Calcutta, Kolkata, India
| | - Namrata Bhattacharya
- Department of Computer Science and Engineering, Indraprastha Institute of Information Technology, Delhi, India
| | - Sunirmal Khatua
- Department of Computer Science and Engineering, University of Calcutta, Kolkata, India
| | - Zhumur Ghosh
- Division of Bioinformatics, Bose Institute, Kolkata, India
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10
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Lin HH, Horie M, Tomonaga K. A comprehensive profiling of innate immune responses in Eptesicus bat cells. Microbiol Immunol 2021; 66:97-112. [PMID: 34842304 DOI: 10.1111/1348-0421.12952] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/11/2021] [Accepted: 11/11/2021] [Indexed: 11/29/2022]
Abstract
Bats (the order Chiroptera), including those of the genus Eptesicus, have been reported to serve as reservoirs of several zoonotic viruses. Notably, bats have been reported to lack obvious symptoms of infection with such viruses and are thought to have unique immune system responses. However, the responses of their innate immune system, the first line of immunity, remain largely unclear. Here, we comprehensively analyzed the expression profiles in two Eptesicus bat cell lines to investigate their innate immune responses. The gene expression profiles after polyinosinic-polycytidylic acid (poly (I:C)) induction were similar between the two bat cell lines, but uniquely upregulated differentially expressed genes were also identified. We also revealed that the upregulated genes of Eptesicus bat cells were distinct from those of human epithelial cells in response to induction. Moreover, the basal expression levels of several immune-related genes were higher in bat cells than in human cells. We also identified unannotated novel transcripts that were upregulated after induction and novel microRNAs expressed in bat cells, some of which were upregulated by poly (I:C) treatment. This is the first report to illustrate the innate immune response in Eptesicus bat cells; therefore, this study provides basic and novel insights into bat innate immunity. Our data represent a valuable resource for future studies into bat immunity and the biology of Eptesicus bats. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Hsien-Hen Lin
- Laboratory of RNA Viruses, Department of Virus Research, Institute for Frontier Life and Medical Sciences (InFRONT), Kyoto University, Kyoto, Japan.,Department of Mammalian Regulatory Network, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Masayuki Horie
- Laboratory of RNA Viruses, Department of Virus Research, Institute for Frontier Life and Medical Sciences (InFRONT), Kyoto University, Kyoto, Japan.,Hakubi Center for Advanced Research, Kyoto University, Kyoto, Japan.,Laboratory of Veterinary Microbiology, Division of Veterinary Sciences, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Izumisano, Osaka, Japan
| | - Keizo Tomonaga
- Laboratory of RNA Viruses, Department of Virus Research, Institute for Frontier Life and Medical Sciences (InFRONT), Kyoto University, Kyoto, Japan.,Department of Mammalian Regulatory Network, Graduate School of Biostudies, Kyoto University, Kyoto, Japan.,Department of Molecular Virology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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11
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Huang S, Yoshitake K, Asakawa S. A Review of Discovery Profiling of PIWI-Interacting RNAs and Their Diverse Functions in Metazoans. Int J Mol Sci 2021; 22:ijms222011166. [PMID: 34681826 PMCID: PMC8538981 DOI: 10.3390/ijms222011166] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/11/2021] [Accepted: 10/14/2021] [Indexed: 12/16/2022] Open
Abstract
PIWI-interacting RNAs (piRNAs) are a class of small non-coding RNAs (sncRNAs) that perform crucial biological functions in metazoans and defend against transposable elements (TEs) in germ lines. Recently, ubiquitously expressed piRNAs were discovered in soma and germ lines using small RNA sequencing (sRNA-seq) in humans and animals, providing new insights into the diverse functions of piRNAs. However, the role of piRNAs has not yet been fully elucidated, and sRNA-seq studies continue to reveal different piRNA activities in the genome. In this review, we summarize a set of simplified processes for piRNA analysis in order to provide a useful guide for researchers to perform piRNA research suitable for their study objectives. These processes can help expand the functional research on piRNAs from previously reported sRNA-seq results in metazoans. Ubiquitously expressed piRNAs have been discovered in the soma and germ lines in Annelida, Cnidaria, Echinodermata, Crustacea, Arthropoda, and Mollusca, but they are limited to germ lines in Chordata. The roles of piRNAs in TE silencing, gene expression regulation, epigenetic regulation, embryonic development, immune response, and associated diseases will continue to be discovered via sRNA-seq.
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Affiliation(s)
- Songqian Huang
- Correspondence: (S.H.); (S.A.); Tel.: +81-3-5841-5296 (S.A.); Fax: +81-3-5841-8166 (S.A.)
| | | | - Shuichi Asakawa
- Correspondence: (S.H.); (S.A.); Tel.: +81-3-5841-5296 (S.A.); Fax: +81-3-5841-8166 (S.A.)
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12
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Pasquesi GIM, Perry BW, Vandewege MW, Ruggiero RP, Schield DR, Castoe TA. Vertebrate Lineages Exhibit Diverse Patterns of Transposable Element Regulation and Expression across Tissues. Genome Biol Evol 2021; 12:506-521. [PMID: 32271917 PMCID: PMC7211425 DOI: 10.1093/gbe/evaa068] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2020] [Indexed: 12/11/2022] Open
Abstract
Transposable elements (TEs) comprise a major fraction of vertebrate genomes, yet little is known about their expression and regulation across tissues, and how this varies across major vertebrate lineages. We present the first comparative analysis integrating TE expression and TE regulatory pathway activity in somatic and gametic tissues for a diverse set of 12 vertebrates. We conduct simultaneous gene and TE expression analyses to characterize patterns of TE expression and TE regulation across vertebrates and examine relationships between these features. We find remarkable variation in the expression of genes involved in TE negative regulation across tissues and species, yet consistently high expression in germline tissues, particularly in testes. Most vertebrates show comparably high levels of TE regulatory pathway activity across gonadal tissues except for mammals, where reduced activity of TE regulatory pathways in ovarian tissues may be the result of lower relative germ cell densities. We also find that all vertebrate lineages examined exhibit remarkably high levels of TE-derived transcripts in somatic and gametic tissues, with recently active TE families showing higher expression in gametic tissues. Although most TE-derived transcripts originate from inactive ancient TE families (and are likely incapable of transposition), such high levels of TE-derived RNA in the cytoplasm may have secondary, unappreciated biological relevance.
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Affiliation(s)
- Giulia I M Pasquesi
- Department of Biology, University of Texas at Arlington.,Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington
| | | | | | - Drew R Schield
- Department of Biology, University of Texas at Arlington.,Department of Ecology and Evolutionary Biology, University of Colorado, Boulder
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington
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13
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Mastora E, Christodoulaki A, Papageorgiou K, Zikopoulos A, Georgiou I. Expression of Retroelements in Mammalian Gametes and Embryos. In Vivo 2021; 35:1921-1927. [PMID: 34182464 DOI: 10.21873/invivo.12458] [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: 04/12/2021] [Revised: 05/18/2021] [Accepted: 05/24/2021] [Indexed: 11/10/2022]
Abstract
Retroelements are genetic mobile elements, expressed during male and female gamete differentiation. Retrotransposons are normally regulated by the methylation machinery, chromatin modifications, non-coding RNAs, and transcription factors, while retrotransposition control is of vital importance in cellular proliferation and differentiation process. Retrotransposition requires a transcription step, by a cellular RNA polymerase, followed by reverse transcription of an RNA intermediate to cDNA and its integration into a new genomic locus. Long interspersed elements (LINEs), human endogenous retroviruses (HERVs), short interspersed elements (SINEs) and SINE-VNTR-Alu elements (SVAs) constitute about half of the human genome, play a crucial role in genome organization, structure and function and interfere with several biological procedures. In this mini review, we discuss recent data regarding retroelement expression (LINE-1, HERVK-10, SVA and VL30) and retrotransposition events in mammalian oocytes and spermatozoa, as well as the importance of their impact on human and mouse preimplantation embryo development.
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Affiliation(s)
- Eirini Mastora
- Laboratory of Medical Genetics, School of Medicine, University of Ioannina and Medical Genetics and Assisted Reproduction Unit, Department of Obstetrics and Gynecology, University Hospital of Ioannina, Ioannina, Greece
| | - Antonia Christodoulaki
- Laboratory of Medical Genetics, School of Medicine, University of Ioannina and Medical Genetics and Assisted Reproduction Unit, Department of Obstetrics and Gynecology, University Hospital of Ioannina, Ioannina, Greece
| | - Kyriaki Papageorgiou
- Department of Biological Applications & Technologies, University of Ioannina and Institute of Molecular Biology and Biotechnology, Division of Biomedical Research, Foundation for Research and Technology, Ioannina, Greece
| | - Athanasios Zikopoulos
- Laboratory of Medical Genetics, School of Medicine, University of Ioannina and Medical Genetics and Assisted Reproduction Unit, Department of Obstetrics and Gynecology, University Hospital of Ioannina, Ioannina, Greece
| | - Ioannis Georgiou
- Laboratory of Medical Genetics, School of Medicine, University of Ioannina and Medical Genetics and Assisted Reproduction Unit, Department of Obstetrics and Gynecology, University Hospital of Ioannina, Ioannina, Greece;
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14
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Palacios-Gimenez OM, Koelman J, Palmada-Flores M, Bradford TM, Jones KK, Cooper SJB, Kawakami T, Suh A. Comparative analysis of morabine grasshopper genomes reveals highly abundant transposable elements and rapidly proliferating satellite DNA repeats. BMC Biol 2020; 18:199. [PMID: 33349252 PMCID: PMC7754599 DOI: 10.1186/s12915-020-00925-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 11/10/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Repetitive DNA sequences, including transposable elements (TEs) and tandemly repeated satellite DNA (satDNAs), collectively called the "repeatome", are found in high proportion in organisms across the Tree of Life. Grasshoppers have large genomes, averaging 9 Gb, that contain a high proportion of repetitive DNA, which has hampered progress in assembling reference genomes. Here we combined linked-read genomics with transcriptomics to assemble, characterize, and compare the structure of repetitive DNA sequences in four chromosomal races of the morabine grasshopper Vandiemenella viatica species complex and determine their contribution to genome evolution. RESULTS We obtained linked-read genome assemblies of 2.73-3.27 Gb from estimated genome sizes of 4.26-5.07 Gb DNA per haploid genome of the four chromosomal races of V. viatica. These constitute the third largest insect genomes assembled so far. Combining complementary annotation tools and manual curation, we found a large diversity of TEs and satDNAs, constituting 66 to 75% per genome assembly. A comparison of sequence divergence within the TE classes revealed massive accumulation of recent TEs in all four races (314-463 Mb per assembly), indicating that their large genome sizes are likely due to similar rates of TE accumulation. Transcriptome sequencing showed more biased TE expression in reproductive tissues than somatic tissues, implying permissive transcription in gametogenesis. Out of 129 satDNA families, 102 satDNA families were shared among the four chromosomal races, which likely represent a diversity of satDNA families in the ancestor of the V. viatica chromosomal races. Notably, 50 of these shared satDNA families underwent differential proliferation since the recent diversification of the V. viatica species complex. CONCLUSION This in-depth annotation of the repeatome in morabine grasshoppers provided new insights into the genome evolution of Orthoptera. Our TEs analysis revealed a massive recent accumulation of TEs equivalent to the size of entire Drosophila genomes, which likely explains the large genome sizes in grasshoppers. Despite an overall high similarity of the TE and satDNA diversity between races, the patterns of TE expression and satDNA proliferation suggest rapid evolution of grasshopper genomes on recent timescales.
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Affiliation(s)
- Octavio M Palacios-Gimenez
- Department of Ecology and Genetics - Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36, Uppsala, Sweden.
- Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36, Uppsala, Sweden.
| | - Julia Koelman
- Department of Ecology and Genetics - Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36, Uppsala, Sweden
| | - Marc Palmada-Flores
- Department of Ecology and Genetics - Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36, Uppsala, Sweden
| | - Tessa M Bradford
- Evolutionary Biology Unit, South Australian Museum, Adelaide, SA, 5000, Australia
- School of Biological Sciences and Australian Centre for Evolutionary Biology and Biodiversity, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Karl K Jones
- Evolutionary Biology Unit, South Australian Museum, Adelaide, SA, 5000, Australia
| | - Steven J B Cooper
- Evolutionary Biology Unit, South Australian Museum, Adelaide, SA, 5000, Australia
- School of Biological Sciences and Australian Centre for Evolutionary Biology and Biodiversity, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Takeshi Kawakami
- Department of Ecology and Genetics - Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36, Uppsala, Sweden.
- Embark Veterinary, Inc., Boston, MA, USA.
| | - Alexander Suh
- Department of Ecology and Genetics - Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36, Uppsala, Sweden.
- Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36, Uppsala, Sweden.
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TU, UK.
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15
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Gemmell NJ, Rutherford K, Prost S, Tollis M, Winter D, Macey JR, Adelson DL, Suh A, Bertozzi T, Grau JH, Organ C, Gardner PP, Muffato M, Patricio M, Billis K, Martin FJ, Flicek P, Petersen B, Kang L, Michalak P, Buckley TR, Wilson M, Cheng Y, Miller H, Schott RK, Jordan MD, Newcomb RD, Arroyo JI, Valenzuela N, Hore TA, Renart J, Peona V, Peart CR, Warmuth VM, Zeng L, Kortschak RD, Raison JM, Zapata VV, Wu Z, Santesmasses D, Mariotti M, Guigó R, Rupp SM, Twort VG, Dussex N, Taylor H, Abe H, Bond DM, Paterson JM, Mulcahy DG, Gonzalez VL, Barbieri CG, DeMeo DP, Pabinger S, Van Stijn T, Clarke S, Ryder O, Edwards SV, Salzberg SL, Anderson L, Nelson N, Stone C. The tuatara genome reveals ancient features of amniote evolution. Nature 2020; 584:403-409. [PMID: 32760000 PMCID: PMC7116210 DOI: 10.1038/s41586-020-2561-9] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 06/26/2020] [Indexed: 12/21/2022]
Abstract
The tuatara (Sphenodon punctatus)-the only living member of the reptilian order Rhynchocephalia (Sphenodontia), once widespread across Gondwana1,2-is an iconic species that is endemic to New Zealand2,3. A key link to the now-extinct stem reptiles (from which dinosaurs, modern reptiles, birds and mammals evolved), the tuatara provides key insights into the ancestral amniotes2,4. Here we analyse the genome of the tuatara, which-at approximately 5 Gb-is among the largest of the vertebrate genomes yet assembled. Our analyses of this genome, along with comparisons with other vertebrate genomes, reinforce the uniqueness of the tuatara. Phylogenetic analyses indicate that the tuatara lineage diverged from that of snakes and lizards around 250 million years ago. This lineage also shows moderate rates of molecular evolution, with instances of punctuated evolution. Our genome sequence analysis identifies expansions of proteins, non-protein-coding RNA families and repeat elements, the latter of which show an amalgam of reptilian and mammalian features. The sequencing of the tuatara genome provides a valuable resource for deep comparative analyses of tetrapods, as well as for tuatara biology and conservation. Our study also provides important insights into both the technical challenges and the cultural obligations that are associated with genome sequencing.
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Affiliation(s)
- Neil J Gemmell
- Department of Anatomy, University of Otago, Dunedin, New Zealand.
| | - Kim Rutherford
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Stefan Prost
- LOEWE-Center for Translational Biodiversity Genomics, Senckenberg Museum, Frankfurt, Germany
- South African National Biodiversity Institute, National Zoological Garden, Pretoria, South Africa
| | - Marc Tollis
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
| | - David Winter
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | | | - David L Adelson
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Alexander Suh
- Department of Ecology and Genetics - Evolutionary Biology, Evolutionary Biology Centre (EBC), Uppsala University, Uppsala, Sweden
- Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre (EBC), Uppsala University, Uppsala, Sweden
| | - Terry Bertozzi
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia
- Evolutionary Biology Unit, South Australian Museum, Adelaide, South Australia, Australia
| | - José H Grau
- Amedes Genetics, Amedes Medizinische Dienstleistungen, Berlin, Germany
- Museum für Naturkunde Berlin, Leibniz-Institut für Evolutions- und Biodiversitätsforschung an der Humboldt-Universität zu Berlin, Berlin, Germany
| | - Chris Organ
- Department of Earth Sciences, Montana State University, Bozeman, MT, USA
| | - Paul P Gardner
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Matthieu Muffato
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, UK
| | - Mateus Patricio
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, UK
| | - Konstantinos Billis
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, UK
| | - Fergal J Martin
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, UK
| | - Paul Flicek
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, UK
| | - Bent Petersen
- Section for Evolutionary Genomics, The GLOBE Institute, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lin Kang
- Edward Via College of Osteopathic Medicine, Blacksburg, VA, USA
| | - Pawel Michalak
- Edward Via College of Osteopathic Medicine, Blacksburg, VA, USA
- Center for One Health Research, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA, USA
- Institute of Evolution, University of Haifa, Haifa, Israel
| | - Thomas R Buckley
- Manaaki Whenua - Landcare Research, Auckland, New Zealand
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Melissa Wilson
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Yuanyuan Cheng
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | | | - Ryan K Schott
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Melissa D Jordan
- The New Zealand Institute for Plant and Food Research, Auckland, New Zealand
| | - Richard D Newcomb
- The New Zealand Institute for Plant and Food Research, Auckland, New Zealand
| | - José Ignacio Arroyo
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nicole Valenzuela
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
| | - Tim A Hore
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Jaime Renart
- Instituto de Investigaciones Biomédicas 'Alberto Sols' CSIC-UAM, Madrid, Spain
| | - Valentina Peona
- Department of Ecology and Genetics - Evolutionary Biology, Evolutionary Biology Centre (EBC), Uppsala University, Uppsala, Sweden
- Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre (EBC), Uppsala University, Uppsala, Sweden
| | - Claire R Peart
- Department of Ecology and Genetics - Evolutionary Biology, Evolutionary Biology Centre (EBC), Uppsala University, Uppsala, Sweden
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilian University of Munich, Planegg-Martinsried, Germany
| | - Vera M Warmuth
- Department of Ecology and Genetics - Evolutionary Biology, Evolutionary Biology Centre (EBC), Uppsala University, Uppsala, Sweden
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilian University of Munich, Planegg-Martinsried, Germany
| | - Lu Zeng
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - R Daniel Kortschak
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Joy M Raison
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | | | - Zhiqiang Wu
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
| | - Didac Santesmasses
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Marco Mariotti
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Roderic Guigó
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Shawn M Rupp
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Victoria G Twort
- Manaaki Whenua - Landcare Research, Auckland, New Zealand
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Nicolas Dussex
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Helen Taylor
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Hideaki Abe
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Donna M Bond
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - James M Paterson
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Daniel G Mulcahy
- Global Genome Initiative, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Vanessa L Gonzalez
- Global Genome Initiative, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | | | | | - Stephan Pabinger
- Austrian Institute of Technology (AIT), Center for Health and Bioresources, Molecular Diagnostics, Vienna, Austria
| | | | - Shannon Clarke
- AgResearch, Invermay Agricultural Centre, Mosgiel, New Zealand
| | - Oliver Ryder
- San Diego Zoo Institute for Conservation Research, Escondido, CA, USA
| | - Scott V Edwards
- Department of Organismic and Evolutionary Biology and the Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA
| | - Steven L Salzberg
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Lindsay Anderson
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Nicola Nelson
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Clive Stone
- Ngatiwai Trust Board, Whangarei, New Zealand
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16
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Kelleher ES, Barbash DA, Blumenstiel JP. Taming the Turmoil Within: New Insights on the Containment of Transposable Elements. Trends Genet 2020; 36:474-489. [PMID: 32473745 DOI: 10.1016/j.tig.2020.04.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 04/15/2020] [Accepted: 04/17/2020] [Indexed: 12/28/2022]
Abstract
Transposable elements (TEs) are mobile genetic parasites that can exponentially increase their genomic abundance through self-propagation. Classic theoretical papers highlighted the importance of two potentially escalating forces that oppose TE spread: regulated transposition and purifying selection. Here, we review new insights into mechanisms of TE regulation and purifying selection, which reveal the remarkable foresight of these theoretical models. We further highlight emergent connections between transcriptional control enacted by small RNAs and the contribution of TE insertions to structural mutation and host-gene regulation. Finally, we call for increased comparative analysis of TE dynamics and fitness effects, as well as host control mechanisms, to reveal how interconnected forces shape the differential prevalence and distribution of TEs across the tree of life.
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17
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C Silva M, Chibucos M, Munro JB, Daugherty S, Coelho MM, C Silva J. Signature of adaptive evolution in olfactory receptor genes in Cory's Shearwater supports molecular basis for smell in procellariiform seabirds. Sci Rep 2020; 10:543. [PMID: 31953474 PMCID: PMC6969042 DOI: 10.1038/s41598-019-56950-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 12/12/2019] [Indexed: 11/17/2022] Open
Abstract
Olfactory receptors (ORs), encoded by the largest vertebrate multigene family, enable the detection of thousands of unique odorants in the environment and consequently play a critical role in species survival. Here, we advance our knowledge of OR gene evolution in procellariiform seabirds, an avian group which relies on the sense of olfaction for critical ecological functions. We built a cosmid library of Cory's Shearwater (Calonectris borealis) genomic DNA, a model species for the study of olfaction-based navigation, and sequence OR gene-positive cosmid clones with a combination of sequencing technologies. We identified 220 OR open reading frames, 20 of which are full length, intact OR genes, and found a large ratio of partial and pseudogenes to intact OR genes (2:1), suggestive of a dynamic mode of evolution. Phylogenetic analyses revealed that while a few genes cluster with those of other sauropsid species in a γ (gamma) clade that predates the divergence of different avian lineages, most genes belong to an avian-specific γ-c clade, within which sequences cluster by species, suggesting frequent duplication and/or gene conversion events. We identified evidence of positive selection on full length γ-c clade genes. These patterns are consistent with a key role of adaptation in the functional diversification of olfactory receptor genes in a bird lineage that relies extensively on olfaction.
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Affiliation(s)
- Mónica C Silva
- cE3c - Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, 1749-016, Lisboa, Portugal.
| | - Marcus Chibucos
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, USA
| | - James B Munro
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, USA
| | - Sean Daugherty
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, USA
| | - M Manuela Coelho
- cE3c - Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, 1749-016, Lisboa, Portugal
| | - Joana C Silva
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, USA
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18
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Roy J, Das B, Jain N, Mallick B. PIWI‐interacting RNA 39980 promotes tumor progression and reduces drug sensitivity in neuroblastoma cells. J Cell Physiol 2019; 235:2286-2299. [DOI: 10.1002/jcp.29136] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 08/23/2019] [Indexed: 02/06/2023]
Affiliation(s)
- Jyoti Roy
- Department of Life Science, RNAi and Functional Genomics Lab National Institute of Technology Rourkela Rourkela Odisha India
| | - Basudeb Das
- Department of Life Science, RNAi and Functional Genomics Lab National Institute of Technology Rourkela Rourkela Odisha India
| | - Neha Jain
- Department of Life Science, RNAi and Functional Genomics Lab National Institute of Technology Rourkela Rourkela Odisha India
| | - Bibekanand Mallick
- Department of Life Science, RNAi and Functional Genomics Lab National Institute of Technology Rourkela Rourkela Odisha India
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19
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Yang L, Jiang H, Wang Y, Lei Y, Chen J, Sun N, Lv W, Wang C, Near TJ, He S. Expansion of vomeronasal receptor genes ( OlfC) in the evolution of fright reaction in Ostariophysan fishes. Commun Biol 2019; 2:235. [PMID: 31263779 PMCID: PMC6588630 DOI: 10.1038/s42003-019-0479-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 05/28/2019] [Indexed: 12/15/2022] Open
Abstract
Ostariophysans are the most diverse group of freshwater fishes and feature a pheromone-elicited fright reaction. However, the genetic basis of fright reaction is unclear. Here, we compared vomeronasal type 2 receptor-like (OlfC) genes from fishes having and lacking fright reaction, to provide insight into evolution of pheromonal olfaction in fishes. We found OlfC genes expanded remarkably in ostariophysans having fright reaction compared with fishes lacking fright reaction. Phylogenetic analysis indicates OlfC subfamily 9 expanded specifically in ostariophysans having fright reaction. Principle component and phylogenetic logistic regression analysis partitioned fishes by ecotype (having or lacking fright reaction) and identified OlfC subfamily 9 as being an important factor for fright reaction. Expression levels of expanded OlfC subfamily genes after fright reaction in zebrafish changed more than did genes that had not expanded. Furthermore, evidence of positive selection was found in the expanded OlfC proteins in ostariophysan fishes having fright reaction. These results provide new insight into the genetic basis of fright reaction in ostariophysan fish and will enable future research into the mechanism of action of OlfC proteins.
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Affiliation(s)
- Liandong Yang
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 People’s Republic of China
| | - Haifeng Jiang
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 People’s Republic of China
- University of Chinese Academy of Sciences, 100049 Beijing, People’s Republic of China
| | - Ying Wang
- School of Life Sciences, Jianghan University, 430056 Wuhan, People’s Republic of China
| | - Yi Lei
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 People’s Republic of China
- University of Chinese Academy of Sciences, 100049 Beijing, People’s Republic of China
| | - Juan Chen
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 People’s Republic of China
- University of Chinese Academy of Sciences, 100049 Beijing, People’s Republic of China
| | - Ning Sun
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 People’s Republic of China
- University of Chinese Academy of Sciences, 100049 Beijing, People’s Republic of China
| | - Wenqi Lv
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 People’s Republic of China
- University of Chinese Academy of Sciences, 100049 Beijing, People’s Republic of China
| | - Cheng Wang
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 People’s Republic of China
- University of Chinese Academy of Sciences, 100049 Beijing, People’s Republic of China
| | - Thomas J. Near
- Department of Ecology and Evolutionary Biology and Peabody Museum of Natural History, Yale University, New Haven, CT 06520 USA
| | - Shunping He
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 People’s Republic of China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, 650223 Kunming, People’s Republic of China
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20
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Russell SJ, Stalker L, LaMarre J. PIWIs, piRNAs and Retrotransposons: Complex battles during reprogramming in gametes and early embryos. Reprod Domest Anim 2018; 52 Suppl 4:28-38. [PMID: 29052331 DOI: 10.1111/rda.13053] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Gamete and embryo development are indispensable processes for successful reproduction. Cells involved in these processes acquire pluripotency, the ability to differentiate into multiple different cell types, through a series of events known as reprogramming that lead to profound changes in histone and DNA methylation. While essential for pluripotency, this epigenetic remodelling removes constraints that normally limit the expression of genomic sequences known as transposable elements (TEs). Unconstrained TE expression can lead to many deleterious consequences including infertility, so organisms have evolved complex and potent mechanistic arsenals to target and suppress TE expression during reprogramming. This review will focus on the control of transposable elements in gametes and embryos, and one important TE suppressing system known as the PIWI pathway. This broadly conserved, small RNA-targeted silencing mechanism appears critical for fertility in many species and may participate in multiple aspects of gene regulation in reproduction and other contexts.
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Affiliation(s)
- S J Russell
- Department of Biomedical Sciences, University of Guelph, Guelph, ON, Canada
| | - L Stalker
- Department of Biomedical Sciences, University of Guelph, Guelph, ON, Canada
| | - J LaMarre
- Department of Biomedical Sciences, University of Guelph, Guelph, ON, Canada
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21
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Platt RN, Vandewege MW, Ray DA. Mammalian transposable elements and their impacts on genome evolution. Chromosome Res 2018; 26:25-43. [PMID: 29392473 PMCID: PMC5857283 DOI: 10.1007/s10577-017-9570-z] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 12/12/2017] [Accepted: 12/28/2017] [Indexed: 12/22/2022]
Abstract
Transposable elements (TEs) are genetic elements with the ability to mobilize and replicate themselves in a genome. Mammalian genomes are dominated by TEs, which can reach copy numbers in the hundreds of thousands. As a result, TEs have had significant impacts on mammalian evolution. Here we summarize the current understanding of TE content in mammal genomes and find that, with a few exceptions, most fall within a predictable range of observations. First, one third to one half of the genome is derived from TEs. Second, most mammalian genomes are dominated by LINE and SINE retrotransposons, more limited LTR retrotransposons, and minimal DNA transposon accumulation. Third, most mammal genome contains at least one family of actively accumulating retrotransposon. Finally, horizontal transfer of TEs among lineages is rare. TE exaptation events are being recognized with increasing frequency. Despite these beneficial aspects of TE content and activity, the majority of TE insertions are neutral or deleterious. To limit the deleterious effects of TE proliferation, the genome has evolved several defense mechanisms that act at the epigenetic, transcriptional, and post-transcriptional levels. The interaction between TEs and these defense mechanisms has led to an evolutionary arms race where TEs are suppressed, evolve to escape suppression, then are suppressed again as the defense mechanisms undergo compensatory change. The result is complex and constantly evolving interactions between TEs and host genomes.
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Affiliation(s)
- Roy N Platt
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA.
| | | | - David A Ray
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
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22
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Singh G, Roy J, Rout P, Mallick B. Genome-wide profiling of the PIWI-interacting RNA-mRNA regulatory networks in epithelial ovarian cancers. PLoS One 2018; 13:e0190485. [PMID: 29320577 PMCID: PMC5761873 DOI: 10.1371/journal.pone.0190485] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 12/17/2017] [Indexed: 12/27/2022] Open
Abstract
PIWI-interacting (piRNAs), ~23–36 nucleotide-long small non-coding RNAs (sncRNAs), earlier believed to be germline-specific, have now been identified in somatic cells, including cancer cells. These sncRNAs impact critical biological processes by fine-tuning gene expression at post-transcriptional and epigenetic levels. The expression of piRNAs in ovarian cancer, the most lethal gynecologic cancer is largely uncharted. In this study, we investigated the expression of PIWILs by qRT-PCR and western blotting and then identified piRNA transcriptomes in tissues of normal ovary and two most prevalent epithelial ovarian cancer subtypes, serous and endometrioid by small RNA sequencing. We detected 219, 256 and 234 piRNAs in normal ovary, endometrioid and serous ovarian cancer samples respectively. We observed piRNAs are encoded from various genomic regions, among which introns harbor the majority of them. Surprisingly, piRNAs originated from different genomic contexts showed the varied level of conservations across vertebrates. The functional analysis of predicted targets of differentially expressed piRNAs revealed these could modulate key processes and pathways involved in ovarian oncogenesis. Our study provides the first comprehensive piRNA landscape in these samples and a useful resource for further functional studies to decipher new mechanistic views of piRNA-mediated gene regulatory networks affecting ovarian oncogenesis. The RNA-seq data is submitted to GEO database (GSE83794).
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Affiliation(s)
- Garima Singh
- RNAi and Functional Genomics Laboratory, Department of Life Science, National Institute of Technology – Rourkela, Odisha, India
| | - Jyoti Roy
- RNAi and Functional Genomics Laboratory, Department of Life Science, National Institute of Technology – Rourkela, Odisha, India
| | - Pratiti Rout
- RNAi and Functional Genomics Laboratory, Department of Life Science, National Institute of Technology – Rourkela, Odisha, India
| | - Bibekanand Mallick
- RNAi and Functional Genomics Laboratory, Department of Life Science, National Institute of Technology – Rourkela, Odisha, India
- * E-mail: ,
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23
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Gainetdinov I, Skvortsova Y, Kondratieva S, Funikov S, Azhikina T. Two modes of targeting transposable elements by piRNA pathway in human testis. RNA (NEW YORK, N.Y.) 2017; 23:1614-1625. [PMID: 28842508 PMCID: PMC5648030 DOI: 10.1261/rna.060939.117] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 08/23/2017] [Indexed: 06/07/2023]
Abstract
PIWI proteins and their partner small RNAs, termed piRNAs, are known to control transposable elements (TEs) in the germline. Here, we provide evidence that in humans this control is exerted in two different modes. On the one hand, production of piRNAs specifically targeting evolutionarily youngest TEs (L1HS, L1PA2-L1PA6, LTR12C, SVA) is present both at prenatal and postnatal stages of spermatogenesis and is performed without involvement of piRNA clusters. On the other hand, at postnatal stages, piRNAs deriving from pachytene clusters target "older" TEs and thus complement cluster-independent piRNA production to achieve relevant targeting of virtually all TEs expressed in postnatal testis. We also find that converging transcription of antisense-oriented genes contributes to the origin of genic postnatal prepachytene clusters. Finally, while a fraction of pachytene piRNAs was previously shown to arise from long intergenic noncoding RNAs (lincRNAs, i.e., pachytene piRNA cluster primary transcripts), we ascertain that these are a specific set of lincRNAs that both possess distinguishing epigenetic features and are expressed exclusively in testis.
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Affiliation(s)
- Ildar Gainetdinov
- Department of Genomics and Postgenomic Technologies, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Yulia Skvortsova
- Department of Genomics and Postgenomic Technologies, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Sofia Kondratieva
- Department of Genomics and Postgenomic Technologies, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Sergey Funikov
- Department of Structural, Functional and Evolutionary Genomics, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Tatyana Azhikina
- Department of Genomics and Postgenomic Technologies, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
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24
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Platt RN, Mangum SF, Ray DA. Pinpointing the vesper bat transposon revolution using the Miniopterus natalensis genome. Mob DNA 2016; 7:12. [PMID: 27489570 PMCID: PMC4971623 DOI: 10.1186/s13100-016-0071-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 07/13/2016] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Around 40 million years ago DNA transposons began accumulating in an ancestor of bats in the family Vespertilionidae. Since that time, Class II transposons have been continuously reinvading and accumulating in vespertilionid genomes at a rate that is unprecedented in mammals. Miniopterus (Miniopteridae), a genus of long-fingered bats that was recently elevated from Vespertilionidae, is the sister taxon to the vespertilionids and is often used as an outgroup when studying transposable elements in vesper bats. Previous wet-lab techniques failed to identify Helitrons, TcMariners, or hAT transposons in Miniopterus. Limitations of those methods and ambiguous results regarding the distribution of piggyBac transposons left some questions as to the distribution of Class II elements in this group. The recent release of the Miniopterus natalensis genome allows for transposable element discovery with a higher degree of precision. RESULTS Here we analyze the transposable element content of M. natalensis to pinpoint with greater accuracy the taxonomic distribution of Class II transposable elements in bats. These efforts demonstrate that, compared to the vespertilionids, Class II TEs are highly mutated and comprise only a small portion of the M. natalensis genome. Despite the limited Class II content, M. natalensis possesses a limited number of lineage-specific, low copy number piggyBacs and shares several TcMariner families with vespertilionid bats. Multiple efforts to identify Helitrons, one of the major TE components of vesper bat genomes, using de novo repeat identification and structural based searches failed. CONCLUSIONS These observations combined with previous results inform our understanding of the events leading to the unique Class II element acquisition that characterizes vespertilionids. While it appears that a small number of TcMariner and piggyBac elements were deposited in the ancestral Miniopterus + vespertilionid genome, these elements are not present in M. natalensis genome at high copy number. Instead, this work indicates that the vesper bats alone experienced the expansion of TEs ranging from Helitrons to piggyBacs to hATs.
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Affiliation(s)
- Roy N Platt
- Department of Biological Sciences, Texas Tech University, Box 43131, Lubbock, TX 79409-3131 USA
| | - Sarah F Mangum
- Department of Biological Sciences, Texas Tech University, Box 43131, Lubbock, TX 79409-3131 USA
| | - David A Ray
- Department of Biological Sciences, Texas Tech University, Box 43131, Lubbock, TX 79409-3131 USA
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