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Abstract
Small RNAs are important regulators of gene expression. They were first identified in Caenorhabditis elegans, but it is now apparent that the main small RNA silencing pathways are functionally conserved across diverse organisms. Availability of genome data for an increasing number of parasitic nematodes has enabled bioinformatic identification of small RNA sequences. Expression of these in different lifecycle stages is revealed by small RNA sequencing and microarray analysis. In this review we describe what is known of the three main small RNA classes in parasitic nematodes – microRNAs (miRNAs), Piwi-interacting RNAs (piRNAs) and small interfering RNAs (siRNAs) – and their proposed functions. miRNAs regulate development in C. elegans and the temporal expression of parasitic nematode miRNAs suggest modulation of target gene levels as parasites develop within the host. miRNAs are also present in extracellular vesicles released by nematodes in vitro, and in plasma from infected hosts, suggesting potential regulation of host gene expression. Roles of piRNAs and siRNAs in suppressing target genes, including transposable elements, are also reviewed. Recent successes in RNAi-mediated gene silencing, and application of small RNA inhibitors and mimics will continue to advance understanding of small RNA functions within the parasite and at the host–parasite interface.
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Matsumoto Y, Piraino S, Miglietta MP. Transcriptome Characterization of Reverse Development in Turritopsis dohrnii (Hydrozoa, Cnidaria). G3 (BETHESDA, MD.) 2019; 9:4127-4138. [PMID: 31619459 PMCID: PMC6893190 DOI: 10.1534/g3.119.400487] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 10/08/2019] [Indexed: 02/08/2023]
Abstract
Medusae of Turritopsis dohrnii undergo reverse development in response to physical damage, adverse environmental conditions, or aging. Senescent, weakened or damaged medusae transform into a cluster of poorly differentiated cells (known as the cyst stage), which metamorphose back into a preceding life cycle stage, the polyp. During the metamorphosis, cell transdifferentiation occurs. The cyst represents the intermediate stage between a reverting medusa and a healthy polyp, during which cell transdifferentiation and tissue reorganization take place. Here we characterize and compare the transcriptomes of the polyp and newborn medusa stages of T. dohrnii with that of the cyst, to identify biological networks potentially involved in the reverse development and transdifferentiation processes. The polyp, medusa and cyst of T. dohrnii were sequenced through Illumina RNA-sequencing and assembled using a de novo approach, resulting in 92,569, 74,639 and 86,373 contigs, respectively. The transcriptomes were annotated and comparative analyses among the stages identified biological networks that were significantly over-and under-expressed in the cyst as compared to the polyp and medusa stages. Biological processes that occur at the cyst stage such as telomerase activity, regulation of transposable elements and DNA repair systems, and suppression of cell signaling pathways, mitotic cell division and cellular differentiation and development may be involved in T. dohrnii's reverse development and transdifferentiation. Our results are the first attempt to understand T. dohrnii's life-cycle reversal at the genetic level, and indicate possible avenues of future research on developmental strategies, cell transdifferentiation, and aging using T. dohrnii as a non-traditional in vivo system.
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Affiliation(s)
- Yui Matsumoto
- Texas A&M University at Galveston, Galveston, TX and
| | - Stefano Piraino
- Università del Salento, Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, 73100 Lecce, Italy
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53
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Yao H, Wang X, Song J, Wang Y, Song Q, Han J. Coxsackievirus B3 infection induces changes in the expression of numerous piRNAs. Arch Virol 2019; 165:105-114. [PMID: 31741095 DOI: 10.1007/s00705-019-04451-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Accepted: 09/26/2019] [Indexed: 01/02/2023]
Abstract
Piwi-interacting RNAs (piRNAs) play pivotal roles in spermatogenesis and are widely distributed among somatic tissues. However, little is known about piRNAs in HeLa cells infected with coxsackievirus B3 (CVB3). In this study, we systematically investigated changes in piRNA expression in HeLa cells infected with CVB3 using high-throughput sequencing technology. piRNA expression profiles in CVB3-infected HeLa cells were examined at 3, 6 and 9 h postinfection (pi). Of the 32,826 piRNAs that were annotated in the NCBI database, 151,571, 89,698 and 76,626 piRNAs were detected in CVB3-infected HeLa cells at 3, 6 and 9 h pi, respectively. Compared with normal cells, 211, 72 and 94 piRNAs were differentially expressed in CVB3-infected HeLa cells at 3, 6 and 9 h pi, respectively. Thirteen piRNAs, including four novel piRNAs, exhibited concurrent changes in CVB3-infected HeLa cells. The changes in the expression of these 13 piRNAs was confirmed in CVB3-infected HeLa cells and 293T cells by stem-loop RT-qPCR at 3, 6 and 9 h pi. The target genes of 13 piRNAs were predicted. The four novel piRNAs were associated with LTR/ERV, LINE/L1 and LTR/ERVK repetitive elements located on different chromosomes. These findings may promote a better understanding of the regulatory mechanism of pathophysiological changes induced by CVB3 infection.
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Affiliation(s)
- Hailan Yao
- Molecular Immunology Laboratory, Capital Institute of Pediatrics, 2 YaBao Rd, Beijing, 100020, China
| | - Xinling Wang
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, 155 Changbai Rd, Beijing, 102206, China
| | - Juan Song
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, 155 Changbai Rd, Beijing, 102206, China
| | - Yanhai Wang
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, 155 Changbai Rd, Beijing, 102206, China
| | - Qinqin Song
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, 155 Changbai Rd, Beijing, 102206, China
| | - Jun Han
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, 155 Changbai Rd, Beijing, 102206, China.
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54
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piRNA-Guided CRISPR-like Immunity in Eukaryotes. Trends Immunol 2019; 40:998-1010. [DOI: 10.1016/j.it.2019.09.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 09/17/2019] [Accepted: 09/17/2019] [Indexed: 02/07/2023]
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55
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Mehta AS, Singh A. Insights into regeneration tool box: An animal model approach. Dev Biol 2019; 453:111-129. [PMID: 30986388 PMCID: PMC6684456 DOI: 10.1016/j.ydbio.2019.04.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/04/2019] [Accepted: 04/09/2019] [Indexed: 12/20/2022]
Abstract
For ages, regeneration has intrigued countless biologists, clinicians, and biomedical engineers. In recent years, significant progress made in identification and characterization of a regeneration tool kit has helped the scientific community to understand the mechanism(s) involved in regeneration across animal kingdom. These mechanistic insights revealed that evolutionarily conserved pathways like Wnt, Notch, Hedgehog, BMP, and JAK/STAT are involved in regeneration. Furthermore, advancement in high throughput screening approaches like transcriptomic analysis followed by proteomic validations have discovered many novel genes, and regeneration specific enhancers that are specific to highly regenerative species like Hydra, Planaria, Newts, and Zebrafish. Since genetic machinery is highly conserved across the animal kingdom, it is possible to engineer these genes and regeneration specific enhancers in species with limited regeneration properties like Drosophila, and mammals. Since these models are highly versatile and genetically tractable, cross-species comparative studies can generate mechanistic insights in regeneration for animals with long gestation periods e.g. Newts. In addition, it will allow extrapolation of regenerative capabilities from highly regenerative species to animals with low regeneration potential, e.g. mammals. In future, these studies, along with advancement in tissue engineering applications, can have strong implications in the field of regenerative medicine and stem cell biology.
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Affiliation(s)
- Abijeet S Mehta
- Department of Biology, University of Dayton, Dayton, OH, 45469, USA
| | - Amit Singh
- Department of Biology, University of Dayton, Dayton, OH, 45469, USA; Premedical Program, University of Dayton, Dayton, OH, 45469, USA; Center for Tissue Regeneration and Engineering at Dayton (TREND), University of Dayton, Dayton, OH, 45469, USA; The Integrative Science and Engineering Center, University of Dayton, Dayton, OH, 45469, USA; Center for Genomic Advocacy (TCGA), Indiana State University, Terre Haute, IN, USA.
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56
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Yap WY, Tan KJSX, Hwang JS. Expansion of Hydra actinoporin-like toxin (HALT) gene family: Expression divergence and functional convergence evolved through gene duplication. Toxicon 2019; 170:10-20. [PMID: 31513812 DOI: 10.1016/j.toxicon.2019.09.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 08/27/2019] [Accepted: 09/03/2019] [Indexed: 11/15/2022]
Abstract
Hydra actinoporin-like toxin 1 (HALT-1) was previously shown to cause cytolysis and haemolysis in a number of human cells and has similar functional properties to the actinoporins equinatoxin and sticholysin. In addition to HALT-1, five other HALTs (HALTs 2, 3, 4, 6 and 7) were also isolated from Hydra magnipapillata and expressed as recombinant proteins in this study. We demonstrated that recombinant HALTs have cytolytic activity on HeLa cells but each exhibited a different range of toxicity. All six recombinant HALTs bound to sulfatide, while rHALT-1 and rHALT-3 bound to two additional sphingolipids, lysophosphatidic acid and sphingosine-1-phosphate as indicated by the protein-lipid overlay assay. When either tryptophan133 or tyrosine129 of HALT-1 was mutated, the mutant protein lost binding to sulfatide, lysophosphatidic acid and sphingosine-1-phosphate. As further verification of HALTs' binding to sulfatide, we performed ELISA for each HALT. To determine the cell-type specific gene expression of seven HALTs in Hydra, we searched for individual HALT expression in the single-cell RNA-seq data set of Single Cell Portal. The results showed that HALT-1, 4 and 7 were expressed in differentiating stenoteles. HALT-1 and HALT-6 were expressed in the female germline during oogenesis. HALT-2 was strongly expressed in the gland and mucous cells in the endoderm. Information on HALT-3 and HALT-5 could not be found in the single-cell data set. Our findings show that subfunctionalisation of gene expression following duplication enabled HALTs to become specialized in various cell types of the interstitial cell lineage.
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Affiliation(s)
- Wei Yuen Yap
- Faculty of Applied Sciences, UCSI University, No. 1, Jalan Menara Gading, UCSI Heights Cheras, 56000, Kuala Lumpur, Malaysia
| | - Katrina Joan Shu Xian Tan
- Faculty of Applied Sciences, UCSI University, No. 1, Jalan Menara Gading, UCSI Heights Cheras, 56000, Kuala Lumpur, Malaysia
| | - Jung Shan Hwang
- Department of Medical Sciences, School of Healthcare and Medical Sciences, Sunway University, No. 5 Jalan Universiti, Bandar Sunway, 47500, Selangor Darul Ehsan, Malaysia.
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57
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Condamine T, Jager M, Leclère L, Blugeon C, Lemoine S, Copley RR, Manuel M. Molecular characterisation of a cellular conveyor belt in Clytia medusae. Dev Biol 2019; 456:212-225. [PMID: 31509769 DOI: 10.1016/j.ydbio.2019.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/29/2019] [Accepted: 09/07/2019] [Indexed: 11/25/2022]
Abstract
The tentacular system of Clytia hemisphaerica medusa (Cnidaria, Hydrozoa) has recently emerged as a promising experimental model to tackle the developmental mechanisms that regulate cell lineage progression in an early-diverging animal phylum. From a population of proximal stem cells, the successive steps of tentacle stinging cell (nematocyte) elaboration, are spatially ordered along a "cellular conveyor belt". Furthermore, the C. hemisphaerica tentacular system exhibits bilateral organisation, with two perpendicular polarity axes (proximo-distal and oral-aboral). We aimed to improve our knowledge of this cellular system by combining RNAseq-based differential gene expression analyses and expression studies of Wnt signalling genes. RNAseq comparisons of gene expression levels were performed (i) between the tentacular system and a control medusa deprived of all tentacles, nematogenic sites and gonads, and (ii) between three samples staggered along the cellular conveyor belt. The behaviour in these differential expression analyses of two reference gene sets (stem cell genes; nematocyte genes), as well as the relative representations of selected gene ontology categories, support the validity of the cellular conveyor belt model. Expression patterns obtained by in situ hybridisation for selected highly differentially expressed genes and for Wnt signalling genes are largely consistent with the results from RNAseq. Wnt signalling genes exhibit complex spatial deployment along both polarity axes of the tentacular system, with the Wnt/β-catenin pathway probably acting along the oral-aboral axis rather than the proximo-distal axis. These findings reinforce the idea that, despite overall radial symmetry, cnidarians have a full potential for elaboration of bilateral structures based on finely orchestrated deployment of an ancient developmental gene toolkit.
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Affiliation(s)
- Thomas Condamine
- Sorbonne Université, MNHN, CNRS, EPHE, Institut de Systématique, Evolution, Biodiversité (ISYEB UMR 7205), Paris, France
| | - Muriel Jager
- Sorbonne Université, MNHN, CNRS, EPHE, Institut de Systématique, Evolution, Biodiversité (ISYEB UMR 7205), Paris, France
| | - Lucas Leclère
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, 181 chemin du Lazaret, 06230, Villefranche-sur-mer, France
| | - Corinne Blugeon
- Genomic Paris Centre, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France
| | - Sophie Lemoine
- Genomic Paris Centre, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France
| | - Richard R Copley
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, 181 chemin du Lazaret, 06230, Villefranche-sur-mer, France
| | - Michaël Manuel
- Sorbonne Université, MNHN, CNRS, EPHE, Institut de Systématique, Evolution, Biodiversité (ISYEB UMR 7205), Paris, France.
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58
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Siebert S, Farrell JA, Cazet JF, Abeykoon Y, Primack AS, Schnitzler CE, Juliano CE. Stem cell differentiation trajectories in Hydra resolved at single-cell resolution. Science 2019; 365:eaav9314. [PMID: 31346039 PMCID: PMC7104783 DOI: 10.1126/science.aav9314] [Citation(s) in RCA: 188] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 06/11/2019] [Indexed: 12/31/2022]
Abstract
The adult Hydra polyp continually renews all of its cells using three separate stem cell populations, but the genetic pathways enabling this homeostatic tissue maintenance are not well understood. We sequenced 24,985 Hydra single-cell transcriptomes and identified the molecular signatures of a broad spectrum of cell states, from stem cells to terminally differentiated cells. We constructed differentiation trajectories for each cell lineage and identified gene modules and putative regulators expressed along these trajectories, thus creating a comprehensive molecular map of all developmental lineages in the adult animal. In addition, we built a gene expression map of the Hydra nervous system. Our work constitutes a resource for addressing questions regarding the evolution of metazoan developmental processes and nervous system function.
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Affiliation(s)
- Stefan Siebert
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA.
| | - Jeffrey A Farrell
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Jack F Cazet
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - Yashodara Abeykoon
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - Abby S Primack
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - Christine E Schnitzler
- Whitney Laboratory for Marine Bioscience and Department of Biology, University of Florida, St. Augustine, FL, USA
| | - Celina E Juliano
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA.
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59
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Ozata DM, Gainetdinov I, Zoch A, O'Carroll D, Zamore PD. PIWI-interacting RNAs: small RNAs with big functions. Nat Rev Genet 2019; 20:89-108. [PMID: 30446728 DOI: 10.1038/s41576-018-0073-3] [Citation(s) in RCA: 666] [Impact Index Per Article: 133.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In animals, PIWI-interacting RNAs (piRNAs) of 21-35 nucleotides in length silence transposable elements, regulate gene expression and fight viral infection. piRNAs guide PIWI proteins to cleave target RNA, promote heterochromatin assembly and methylate DNA. The architecture of the piRNA pathway allows it both to provide adaptive, sequence-based immunity to rapidly evolving viruses and transposons and to regulate conserved host genes. piRNAs silence transposons in the germ line of most animals, whereas somatic piRNA functions have been lost, gained and lost again across evolution. Moreover, most piRNA pathway proteins are deeply conserved, but different animals employ remarkably divergent strategies to produce piRNA precursor transcripts. Here, we discuss how a common piRNA pathway allows animals to recognize diverse targets, ranging from selfish genetic elements to genes essential for gametogenesis.
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Affiliation(s)
- Deniz M Ozata
- RNA Therapeutics Institute and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Ildar Gainetdinov
- RNA Therapeutics Institute and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Ansgar Zoch
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Dónal O'Carroll
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.,Wellcome Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, UK
| | - Phillip D Zamore
- RNA Therapeutics Institute and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA, USA.
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60
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Gebert D, Zischler H, Rosenkranz D. Primate piRNA Cluster Evolution Suggests Limited Relevance of Pseudogenes in piRNA-Mediated Gene Regulation. Genome Biol Evol 2019; 11:1088-1104. [PMID: 30888404 PMCID: PMC6461890 DOI: 10.1093/gbe/evz060] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2019] [Indexed: 12/11/2022] Open
Abstract
PIWI proteins and their guiding Piwi-interacting (pi-) RNAs direct the silencing of target nucleic acids in the animal germline and soma. Although in mammal testes fetal piRNAs are involved in extensive silencing of transposons, pachytene piRNAs have additionally been shown to act in post-transcriptional gene regulation. The bulk of pachytene piRNAs is produced from large genomic loci, named piRNA clusters. Recently, the presence of reversed pseudogenes within piRNA clusters prompted the idea that piRNAs derived from such sequences might direct regulation of their parent genes. Here, we examine primate piRNA clusters and integrated pseudogenes in a comparative approach to gain a deeper understanding about mammalian piRNA cluster evolution and the presumed gene-regulatory role of pseudogene-derived piRNAs. Initially, we provide a broad analysis of the evolutionary relationships of piRNA clusters and their differential activity among six primate species. Subsequently, we show that pseudogenes in reserve orientation relative to piRNA cluster transcription direction generally do not exhibit signs of selection pressure and cause weakly conserved targeting of homologous genes among species, suggesting a lack of functional constraints and thus only a minor significance for gene regulation in most cases. Finally, we report that piRNA-producing loci generally tend to be located in active genomic regions with elevated gene and pseudogene density. Thus, we conclude that the presence of most pseudogenes in piRNA clusters might be regarded as a byproduct of piRNA cluster generation, whereas this does not exclude that some pseudogenes nevertheless play critical roles in individual cases.
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Affiliation(s)
- Daniel Gebert
- Institute of Organismic and Molecular Evolution, Anthropology, Johannes Gutenberg University, Mainz, Germany
| | - Hans Zischler
- Institute of Organismic and Molecular Evolution, Anthropology, Johannes Gutenberg University, Mainz, Germany
| | - David Rosenkranz
- Institute of Organismic and Molecular Evolution, Anthropology, Johannes Gutenberg University, Mainz, Germany
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61
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Transgenesis in Hydra to characterize gene function and visualize cell behavior. Nat Protoc 2019; 14:2069-2090. [DOI: 10.1038/s41596-019-0173-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 04/04/2019] [Indexed: 12/13/2022]
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62
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Huang S, Ichikawa Y, Igarashi Y, Yoshitake K, Kinoshita S, Omori F, Maeyama K, Nagai K, Watabe S, Asakawa S. Piwi-interacting RNA (piRNA) expression patterns in pearl oyster (Pinctada fucata) somatic tissues. Sci Rep 2019; 9:247. [PMID: 30670741 PMCID: PMC6342924 DOI: 10.1038/s41598-018-36726-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 11/19/2018] [Indexed: 12/31/2022] Open
Abstract
Piwi-interacting RNAs (piRNAs) belong to a recently discovered class of small non-coding RNAs whose best-understood function is repressing transposable element activity. Most piRNA studies have been conducted on model organisms and little is known about piRNA expression and function in mollusks. We performed high-throughput sequencing of small RNAs extracted from the mantle, adductor muscle, gill, and ovary tissues of the pearl oyster, Pinctada fucata. RNA species with sequences of approximately 30 nt were widely expressed in all tissues. Uridine at the 5' terminal and protection from β-elimination at the 3' terminal suggested that these were putative piRNAs. A total of 18.0 million putative piRNAs were assigned to 2.8 million unique piRNAs, and 35,848 piRNA clusters were identified. Mapping to the reference genome showed that 25% of the unique piRNAs mapped to multiple tandem loci on the scaffold. Expression patterns of the piRNA clusters were similar within the somatic tissues, but differed significantly between the somatic and gonadal tissues. These findings suggest that in pearl oysters piRNAs have important and novel functions beyond those in the germ line.
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Affiliation(s)
- Songqian Huang
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Yuki Ichikawa
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Yoji Igarashi
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Kazutoshi Yoshitake
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Shigeharu Kinoshita
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Fumito Omori
- Mikimoto Pharmaceutical CO., LTD., Kurose 1425, Ise, Mie, 516-8581, Japan
| | - Kaoru Maeyama
- Mikimoto Pharmaceutical CO., LTD., Kurose 1425, Ise, Mie, 516-8581, Japan
| | - Kiyohito Nagai
- Pearl Research Laboratory, K. MIKIMOTO & CO., LTD., Osaki Hazako 923, Hamajima, Shima, Mie, 517-0403, Japan
| | - Shugo Watabe
- School of Marine Biosciences, Kitasato University, Minami-ku, Sagamihara, Kanagawa, 252-0313, Japan
| | - Shuichi Asakawa
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan.
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63
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Gao CL, Sun R, Li DH, Gong F. PIWI-like protein 1 upregulation promotes gastric cancer invasion and metastasis. Onco Targets Ther 2018; 11:8783-8789. [PMID: 30584336 PMCID: PMC6287512 DOI: 10.2147/ott.s186827] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Background PIWI-like protein 1 (PIWIL1) is an important member of the Argonaute protein family and is closely related to the malignant behaviors of tumor cells. This study aimed to investigate the relationship between PIWIL1 and gastric cancer (GC). Methods We investigated PIWIL1 expression status in GC tissues as well as its association with clinicopathological characteristics and prognosis of GC patients. PIWIL1 siRNA was transfected into a GC cell line to elucidate its impact on malignant biological behavior. Results The results showed that PIWIL1 was upregulated in GC tissues and correlated with tumor differentiation, lymph node status, and TNM stage. The high PIWIL1 expression was an independent predictor for the prognosis of patients with GC. Silencing of PIWIL1 expression in GC cell lines suppressed tumor cell proliferation, migration, and invasion. Conclusion High PIWIL1 expression suggests a poor prognosis for GC patients and PIWIL1 can serve as an important molecular marker for predicting the prognosis of GC patients.
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Affiliation(s)
| | | | - Dong-Hai Li
- Department of Pathology, The First People's Hospital of Lanzhou City, Lanzhou, Gansu, 730050, China
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64
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Czech B, Munafò M, Ciabrelli F, Eastwood EL, Fabry MH, Kneuss E, Hannon GJ. piRNA-Guided Genome Defense: From Biogenesis to Silencing. Annu Rev Genet 2018; 52:131-157. [PMID: 30476449 PMCID: PMC10784713 DOI: 10.1146/annurev-genet-120417-031441] [Citation(s) in RCA: 303] [Impact Index Per Article: 50.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
PIWI-interacting RNAs (piRNAs) and their associated PIWI clade Argonaute proteins constitute the core of the piRNA pathway. In gonadal cells, this conserved pathway is crucial for genome defense, and its main function is to silence transposable elements. This is achieved through posttranscriptional and transcriptional gene silencing. Precursors that give rise to piRNAs require specialized transcription and transport machineries because piRNA biogenesis is a cytoplasmic process. The ping-pong cycle, a posttranscriptional silencing mechanism, combines the cleavage-dependent silencing of transposon RNAs with piRNA production. PIWI proteins also function in the nucleus, where they scan for nascent target transcripts with sequence complementarity, instructing transcriptional silencing and deposition of repressive chromatin marks at transposon loci. Although studies have revealed numerous factors that participate in each branch of the piRNA pathway, the precise molecular roles of these factors often remain unclear. In this review, we summarize our current understanding of the mechanisms involved in piRNA biogenesis and function.
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Affiliation(s)
- Benjamin Czech
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Marzia Munafò
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Filippo Ciabrelli
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Evelyn L Eastwood
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Martin H Fabry
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Emma Kneuss
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Gregory J Hannon
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
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Balaratnam S, West N, Basu S. A piRNA utilizes HILI and HIWI2 mediated pathway to down-regulate ferritin heavy chain 1 mRNA in human somatic cells. Nucleic Acids Res 2018; 46:10635-10648. [PMID: 30102404 PMCID: PMC6237762 DOI: 10.1093/nar/gky728] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 07/27/2018] [Accepted: 07/31/2018] [Indexed: 12/18/2022] Open
Abstract
The piwi interacting RNAs (piRNAs) are small non-coding RNAs that specifically bind to the PIWI proteins, a functional requirement. The piRNAs regulate germline development, transposons control, and gene expression. However, piRNA-mediated post-transcriptional gene regulation in human somatic cells is not well understood. We discovered a human piRNA (piR-FTH1) which has a complementary sequence in the ferritin heavy chain 1 (Fth1) mRNA. We demonstrated that expression of piR-FTH1 and Fth1 are inversely correlated in the tested tumor cell lines. We found that piR-FTH1 negatively regulates the Fth1 expression at post-transcriptional level in triple negative breast cancer (TNBC) cells. Additionally, we confirmed that transfected piR-FTH1 knocks down the Fth1 mRNA via the HIWI2 and HILI mediated mechanism. piR-FTH1 mediated Fth1 repression also increased doxorubicin sensitivity by a remarkable 20-fold in TNBC cells. Since the current piRNA-mediated knockdowns of target mRNA are mostly reported in germ line cells, piRNA-mediated post-transcriptional gene regulation in somatic cells is rather unique in its application and mechanistically uses an alternative pathway to siRNA and miRNA. This work begins to lay the groundwork with a broader impact on treatment of various diseases that are linked to elevated levels of specific mRNAs which have a piRNA target.
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Affiliation(s)
- Sumirtha Balaratnam
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Nicole West
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Soumitra Basu
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
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66
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Calcino AD, Fernandez-Valverde SL, Taft RJ, Degnan BM. Diverse RNA interference strategies in early-branching metazoans. BMC Evol Biol 2018; 18:160. [PMID: 30382896 PMCID: PMC6211395 DOI: 10.1186/s12862-018-1274-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 10/08/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Micro RNAs (miRNAs) and piwi interacting RNAs (piRNAs), along with the more ancient eukaryotic endogenous small interfering RNAs (endo-siRNAs) constitute the principal components of the RNA interference (RNAi) repertoire of most animals. RNAi in non-bilaterians - sponges, ctenophores, placozoans and cnidarians - appears to be more diverse than that of bilaterians, and includes structurally variable miRNAs in sponges, an enormous number of piRNAs in cnidarians and the absence of miRNAs in ctenophores and placozoans. RESULTS Here we identify thousands of endo-siRNAs and piRNAs from the sponge Amphimedon queenslandica, the ctenophore Mnemiopsis leidyi and the cnidarian Nematostella vectensis using a computational approach that clusters mapped small RNA sequences and annotates each cluster based on the read length and relative abundance of the constituent reads. This approach was validated on 11 small RNA libraries in Drosophila melanogaster, demonstrating the successful annotation of RNAi-associated loci with properties consistent with previous reports. In the non-bilaterians we uncover seven new miRNAs from Amphimedon and four from Nematostella as well as sub-populations of candidate cis-natural antisense transcript (cis-NAT) endo-siRNAs. We confirmed the absence of miRNAs in Mnemiopsis but detected an abundance of endo-siRNAs in this ctenophore. Analysis of putative piRNA structure suggests that conserved localised secondary structures in primary transcripts may be important for the production of mature piRNAs in Amphimedon and Nematostella, as is also the case for endo-siRNAs. CONCLUSION Together, these findings suggest that the last common ancestor of extant animals did not have the entrained RNAi system that typifies bilaterians. Instead it appears that bilaterians, cnidarians, ctenophores and sponges express unique repertoires and combinations of miRNAs, piRNAs and endo-siRNAs.
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Affiliation(s)
- Andrew D Calcino
- School of Biological Sciences, University of Queensland, Brisbane, QLD, 4072, Australia.,Present address: Department of Integrative Zoology, University of Vienna, Althanstraße 1, 4A-1090, Vienna, Austria
| | - Selene L Fernandez-Valverde
- School of Biological Sciences, University of Queensland, Brisbane, QLD, 4072, Australia.,Present address: CONACYT, Laboratorio Nacional de Genómica para la Biodiversidad (Langebio). CINVESTAV, Irapuato, Guanajuato, Mexico
| | - Ryan J Taft
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia.,Illumina Inc, San Diego, California, 92122, USA
| | - Bernard M Degnan
- School of Biological Sciences, University of Queensland, Brisbane, QLD, 4072, Australia.
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67
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Urbarova I, Patel H, Forêt S, Karlsen BO, Jørgensen TE, Hall-Spencer JM, Johansen SD. Elucidating the Small Regulatory RNA Repertoire of the Sea Anemone Anemonia viridis Based on Whole Genome and Small RNA Sequencing. Genome Biol Evol 2018; 10:410-426. [PMID: 29385567 PMCID: PMC5793845 DOI: 10.1093/gbe/evy003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2018] [Indexed: 12/16/2022] Open
Abstract
Cnidarians harbor a variety of small regulatory RNAs that include microRNAs (miRNAs) and PIWI-interacting RNAs (piRNAs), but detailed information is limited. Here, we report the identification and expression of novel miRNAs and putative piRNAs, as well as their genomic loci, in the symbiotic sea anemone Anemonia viridis. We generated a draft assembly of the A. viridis genome with putative size of 313 Mb that appeared to be composed of about 36% repeats, including known transposable elements. We detected approximately equal fractions of DNA transposons and retrotransposons. Deep sequencing of small RNA libraries constructed from A. viridis adults sampled at a natural CO2 gradient off Vulcano Island, Italy, identified 70 distinct miRNAs. Eight were homologous to previously reported miRNAs in cnidarians, whereas 62 appeared novel. Nine miRNAs were recognized as differentially expressed along the natural seawater pH gradient. We found a highly abundant and diverse population of piRNAs, with a substantial fraction showing ping–pong signatures. We identified nearly 22% putative piRNAs potentially targeting transposable elements within the A. viridis genome. The A. viridis genome appeared similar in size to that of other hexacorals with a very high divergence of transposable elements resembling that of the sea anemone genus Exaiptasia. The genome encodes and expresses a high number of small regulatory RNAs, which include novel miRNAs and piRNAs. Differentially expressed small RNAs along the seawater pH gradient indicated regulatory gene responses to environmental stressors.
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Affiliation(s)
- Ilona Urbarova
- Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Hardip Patel
- Genomics and Predictive Medicine, Genome Biology Department, John Curtin School of Medical Research, ANU College of Medicine, Biology, and Environment, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Sylvain Forêt
- Evolution, Ecology, and Genetics, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Bård Ove Karlsen
- Research Laboratory, Department of Laboratory Medicine, Nordland Hospital, Bodø, Norway
| | - Tor Erik Jørgensen
- Genomics Group, Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
| | - Jason M Hall-Spencer
- Marine Biology and Ecology Research Centre, University of Plymouth, United Kingdom.,Shimoda Marine Research Centre, University of Tsukuba, Shimoda City, Shizuoka, Japan
| | - Steinar D Johansen
- Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway.,Genomics Group, Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
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68
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Rojas-Ríos P, Simonelig M. piRNAs and PIWI proteins: regulators of gene expression in development and stem cells. Development 2018; 145:145/17/dev161786. [PMID: 30194260 DOI: 10.1242/dev.161786] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PIWI proteins and Piwi-interacting RNAs (piRNAs) have established and conserved roles in repressing transposable elements (TEs) in the germline of animals. However, in several biological contexts, a large proportion of piRNAs are not related to TE sequences and, accordingly, functions for piRNAs and PIWI proteins that are independent of TE regulation have been identified. This aspect of piRNA biology is expanding rapidly. Indeed, recent reports have revealed the role of piRNAs in the regulation of endogenous gene expression programs in germ cells, as well as in somatic tissues, challenging dogma in the piRNA field. In this Review, we focus on recent data addressing the biological and developmental functions of piRNAs, highlighting their roles in embryonic patterning, germ cell specification, stem cell biology, neuronal activity and metabolism.
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Affiliation(s)
- Patricia Rojas-Ríos
- mRNA Regulation and Development, IGH, Univ. Montpellier, CNRS, Montpellier 34396, France
| | - Martine Simonelig
- mRNA Regulation and Development, IGH, Univ. Montpellier, CNRS, Montpellier 34396, France
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69
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Jehn J, Gebert D, Pipilescu F, Stern S, Kiefer JST, Hewel C, Rosenkranz D. PIWI genes and piRNAs are ubiquitously expressed in mollusks and show patterns of lineage-specific adaptation. Commun Biol 2018; 1:137. [PMID: 30272016 PMCID: PMC6128900 DOI: 10.1038/s42003-018-0141-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 08/17/2018] [Indexed: 12/14/2022] Open
Abstract
PIWI proteins and PIWI-interacting RNAs (piRNAs) suppress transposon activity in animals, thus protecting their genomes from detrimental insertion mutagenesis. Here, we reveal that PIWI genes and piRNAs are ubiquitously expressed in mollusks, similar to the situation in arthropods. We describe lineage-specific adaptations of transposon composition in piRNA clusters in the great pond snail and the pacific oyster, likely reflecting differential transposon activity in gastropods and bivalves. We further show that different piRNA clusters with unique transposon composition are dynamically expressed during oyster development. Finally, bioinformatics analyses suggest that different populations of piRNAs presumably bound to different PIWI paralogs participate in homotypic and heterotypic ping-pong amplification loops in a tissue- and sex-specific manner. Together with recent findings from other animal species, our results support the idea that somatic piRNA expression represents the ancestral state in metazoans.
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Affiliation(s)
- Julia Jehn
- Institute of Organismic and Molecular Evolution, Anthropology, Johannes Gutenberg University Mainz, Anselm-Franz-von-Bentzel-Weg 7, 55099, Mainz, Germany
| | - Daniel Gebert
- Institute of Organismic and Molecular Evolution, Anthropology, Johannes Gutenberg University Mainz, Anselm-Franz-von-Bentzel-Weg 7, 55099, Mainz, Germany
| | - Frank Pipilescu
- Institute of Organismic and Molecular Evolution, Anthropology, Johannes Gutenberg University Mainz, Anselm-Franz-von-Bentzel-Weg 7, 55099, Mainz, Germany
| | - Sarah Stern
- Institute of Organismic and Molecular Evolution, Anthropology, Johannes Gutenberg University Mainz, Anselm-Franz-von-Bentzel-Weg 7, 55099, Mainz, Germany
| | - Julian Simon Thilo Kiefer
- Institute of Organismic and Molecular Evolution, Anthropology, Johannes Gutenberg University Mainz, Anselm-Franz-von-Bentzel-Weg 7, 55099, Mainz, Germany
| | - Charlotte Hewel
- Institute of Organismic and Molecular Evolution, Anthropology, Johannes Gutenberg University Mainz, Anselm-Franz-von-Bentzel-Weg 7, 55099, Mainz, Germany
| | - David Rosenkranz
- Institute of Organismic and Molecular Evolution, Anthropology, Johannes Gutenberg University Mainz, Anselm-Franz-von-Bentzel-Weg 7, 55099, Mainz, Germany.
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70
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Sanders SM, Ma Z, Hughes JM, Riscoe BM, Gibson GA, Watson AM, Flici H, Frank U, Schnitzler CE, Baxevanis AD, Nicotra ML. CRISPR/Cas9-mediated gene knockin in the hydroid Hydractinia symbiolongicarpus. BMC Genomics 2018; 19:649. [PMID: 30176818 PMCID: PMC6122657 DOI: 10.1186/s12864-018-5032-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 08/22/2018] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Hydractinia symbiolongicarpus, a colonial cnidarian, is a tractable model system for many cnidarian-specific and general biological questions. Until recently, tests of gene function in Hydractinia have relied on laborious forward genetic approaches, randomly integrated transgenes, or transient knockdown of mRNAs. RESULTS Here, we report the use of CRISPR/Cas9 genome editing to generate targeted genomic insertions in H. symbiolonigcarpus. We used CRISPR/Cas9 to promote homologous recombination of two fluorescent reporters, eGFP and tdTomato, into the Eukaryotic elongation factor 1 alpha (Eef1a) locus. We demonstrate that the transgenes are expressed ubiquitously and are stable over two generations of breeding. We further demonstrate that CRISPR/Cas9 genome editing can be used to mark endogenous proteins with FLAG or StrepII-FLAG affinity tags to enable in vivo and ex vivo protein studies. CONCLUSIONS This is the first account of CRISPR/Cas9 mediated knockins in Hydractinia and the first example of the germline transmission of a CRISPR/Cas9 inserted transgene in a cnidarian. The ability to precisely insert exogenous DNA into the Hydractinia genome will enable sophisticated genetic studies and further development of functional genomics tools in this understudied cnidarian model.
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Affiliation(s)
- Steven M. Sanders
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA USA
- Pittsburgh Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA USA
| | - Zhiwei Ma
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA USA
- Pittsburgh Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA USA
| | - Julia M. Hughes
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA USA
- Pittsburgh Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA USA
| | - Brooke M. Riscoe
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA USA
- Pittsburgh Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA USA
| | - Gregory A. Gibson
- Center for Biological Imaging and Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA USA
| | - Alan M. Watson
- Center for Biological Imaging and Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA USA
| | - Hakima Flici
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Uri Frank
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Christine E. Schnitzler
- Whitney Laboratory for Marine Bioscience, and Department of Biology, University of Florida, St. Augustine, FL USA
| | - Andreas D. Baxevanis
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD USA
| | - Matthew L. Nicotra
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA USA
- Pittsburgh Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA USA
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA USA
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71
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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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72
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Modepalli V, Fridrich A, Agron M, Moran Y. The methyltransferase HEN1 is required in Nematostella vectensis for microRNA and piRNA stability as well as larval metamorphosis. PLoS Genet 2018; 14:e1007590. [PMID: 30118479 PMCID: PMC6114907 DOI: 10.1371/journal.pgen.1007590] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 08/29/2018] [Accepted: 07/25/2018] [Indexed: 11/18/2022] Open
Abstract
Small non-coding RNAs (sRNAs) such as microRNAs (miRNAs), small interfering RNAs (siRNAs) and piwi-interacting RNAs (piRNAs) regulate the levels of endogenous, viral and transposable element RNA in plants (excluding piRNAs) and animals. These pathways are explored mainly in bilaterian animals, such as vertebrates, arthropods and nematodes, where siRNAs and piRNAs, but not miRNAs bind their targets with a perfect match and mediate the cleavage of the target RNA. Methylation of the 3′ ends of piRNAs and siRNAs by the methyltransferase HEN1 protects these sRNAs from degradation. There is a noticeable selection in bilaterian animals against miRNA-mRNA perfect matching, as it leads to the degradation of miRNAs. Cnidarians (sea anemones, corals, hydroids and jellyfish), are separated from bilaterians by more than 600 million years. As opposed to bilaterians, cnidarian miRNAs frequently bind their targets with a nearly perfect match. Knowing that an ortholog of HEN1 is widely expressed in the sea anemone Nematostella vectensis, we tested in this work whether it mediates the stabilization of its sRNAs. We show that the knockdown of HEN1 in Nematostella results in a developmental arrest. Small RNA sequencing revealed that the levels of both miRNAs and piRNAs drop dramatically in the morphant animals. Moreover, knockdown experiments of Nematostella Dicer1 and PIWI2, homologs of major bilaterian biogenesis components of miRNAs and piRNAs, respectively, resulted in developmental arrest similar to HEN1 morphants. Our findings suggest that HEN1 mediated methylation of sRNAs reflects the ancestral state, where miRNAs were also methylated. Thus, we provide the first evidence of a methylation mechanism that stabilizes miRNAs in animals, and highlight the importance of post-transcriptional regulation in non-bilaterian animals. Plants and animals use small RNAs to regulate gene expression, virus silencing and genomic integrity. These functions depend on specific binding of small RNAs to longer RNA targets. The methyltransferase HEN1 plays a crucial role in stabilizing small RNAs upon their binding to perfectly-matching targets. Lack of methylation in case of a perfect match will lead to small RNA degradation. In general, methylation of microRNAs, a class of small RNAs, is part of their biogenesis in plants, but not in bilaterian animals such as vertebrates, worms and insects, where perfectly-matching microRNA targets are rare. In contrast, in Cnidaria (sea anemones, corals and jellyfish), the sister group to Bilateria, microRNAs frequently bind their targets with a nearly perfect match. In this study, we show that in the cnidarian Nematostella vectensis methylation of microRNAs and other small RNAs is consistent and frequent throughout development and that knockdown of the cnidarian HEN1 results in a developmental arrest. Small RNA sequencing of the treated animals, reveals that small RNAs are depleted and shortened. Therefore, our findings suggest that HEN1-mediated methylation of small RNAs was present in the last common ancestor of Cnidaria and Bilateria 600 million years ago and was responsible for microRNA stabilization.
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Affiliation(s)
- Vengamanaidu Modepalli
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- * E-mail: (VM); (YM)
| | - Arie Fridrich
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Maayan Agron
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yehu Moran
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- * E-mail: (VM); (YM)
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73
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Waldron FM, Stone GN, Obbard DJ. Metagenomic sequencing suggests a diversity of RNA interference-like responses to viruses across multicellular eukaryotes. PLoS Genet 2018; 14:e1007533. [PMID: 30059538 PMCID: PMC6085071 DOI: 10.1371/journal.pgen.1007533] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 08/09/2018] [Accepted: 07/04/2018] [Indexed: 11/24/2022] Open
Abstract
RNA interference (RNAi)-related pathways target viruses and transposable element (TE) transcripts in plants, fungi, and ecdysozoans (nematodes and arthropods), giving protection against infection and transmission. In each case, this produces abundant TE and virus-derived 20-30nt small RNAs, which provide a characteristic signature of RNAi-mediated defence. The broad phylogenetic distribution of the Argonaute and Dicer-family genes that mediate these pathways suggests that defensive RNAi is ancient, and probably shared by most animal (metazoan) phyla. Indeed, while vertebrates had been thought an exception, it has recently been argued that mammals also possess an antiviral RNAi pathway, although its immunological relevance is currently uncertain and the viral small RNAs (viRNAs) are not easily detectable. Here we use a metagenomic approach to test for the presence of viRNAs in five species from divergent animal phyla (Porifera, Cnidaria, Echinodermata, Mollusca, and Annelida), and in a brown alga-which represents an independent origin of multicellularity from plants, fungi, and animals. We use metagenomic RNA sequencing to identify around 80 virus-like contigs in these lineages, and small RNA sequencing to identify viRNAs derived from those viruses. We identified 21U small RNAs derived from an RNA virus in the brown alga, reminiscent of plant and fungal viRNAs, despite the deep divergence between these lineages. However, contrary to our expectations, we were unable to identify canonical (i.e. Drosophila- or nematode-like) viRNAs in any of the animals, despite the widespread presence of abundant micro-RNAs, and somatic transposon-derived piwi-interacting RNAs. We did identify a distinctive group of small RNAs derived from RNA viruses in the mollusc. However, unlike ecdysozoan viRNAs, these had a piRNA-like length distribution but lacked key signatures of piRNA biogenesis. We also identified primary piRNAs derived from putatively endogenous copies of DNA viruses in the cnidarian and the echinoderm, and an endogenous RNA virus in the mollusc. The absence of canonical virus-derived small RNAs from our samples may suggest that the majority of animal phyla lack an antiviral RNAi response. Alternatively, these phyla could possess an antiviral RNAi response resembling that reported for vertebrates, with cryptic viRNAs not detectable through simple metagenomic sequencing of wild-type individuals. In either case, our findings show that the antiviral RNAi responses of arthropods and nematodes, which are highly divergent from each other and from that of plants and fungi, are also highly diverged from the most likely ancestral metazoan state.
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Affiliation(s)
- Fergal M. Waldron
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, Edinburgh, United Kingdom
| | - Graham N. Stone
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, Edinburgh, United Kingdom
| | - Darren J. Obbard
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, Edinburgh, United Kingdom
- Centre for Immunity Infection and Evolution, University of Edinburgh, Ashworth Laboratories, Edinburgh, United Kingdom
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74
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Kashima M, Agata K, Shibata N. Searching for non-transposable targets of planarian nuclear PIWI in pluripotent stem cells and differentiated cells. Dev Growth Differ 2018; 60:260-277. [DOI: 10.1111/dgd.12536] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 04/07/2018] [Accepted: 04/09/2018] [Indexed: 12/27/2022]
Affiliation(s)
- Makoto Kashima
- Department of Biophysics; Graduate School of Science; Kyoto University; Kyoto Japan
| | - Kiyokazu Agata
- Department of Biophysics; Graduate School of Science; Kyoto University; Kyoto Japan
| | - Norito Shibata
- Department of Biophysics; Graduate School of Science; Kyoto University; Kyoto Japan
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75
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Lenart P, Novak J, Bienertova-Vasku J. PIWI-piRNA pathway: Setting the pace of aging by reducing DNA damage. Mech Ageing Dev 2018; 173:29-38. [PMID: 29580825 DOI: 10.1016/j.mad.2018.03.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 03/02/2018] [Accepted: 03/22/2018] [Indexed: 10/17/2022]
Abstract
Transposable elements (TEs) are powerful drivers of genome evolutionary dynamics but are principally deleterious to the host organism by compromising the integrity and function of the genome. The transposition of TEs may result in mutations and DNA damage. DNA double-strand breaks (DSBs), which may be caused by the transposition, are one of the processes directly linked to aging. TEs may thus be considered to constitute an internal source of aging and the frequency of transposition may, in turn, be considered to affect the pace of aging. The PIWI-piRNA pathway is a widespread strategy used by most animals to effectively suppress transposition. Interestingly, the PIWI-piRNA pathway is expressed predominantly in the animal germline, a more or less continuous immortal lineage set aside after the first few cell divisions of a developing embryo. Recent findings further imply that the PIWI-piRNA pathway and TE suppression constitute an important mechanism regulating aging. This article discusses the proposed role of the PIWI-piRNA pathway in setting the pace of aging as well as the possible mechanisms underlying this process.
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Affiliation(s)
- Peter Lenart
- Department of Pathological Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, Building A18, 625 00, Brno, Czech Republic; Research Centre for Toxic Compounds in the Environment, Faculty of Science, Masaryk University, Kamenice 5, Building A29, 625 00, Brno, Czech Republic
| | - Jan Novak
- Department of Pathological Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, Building A18, 625 00, Brno, Czech Republic
| | - Julie Bienertova-Vasku
- Department of Pathological Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, Building A18, 625 00, Brno, Czech Republic; Research Centre for Toxic Compounds in the Environment, Faculty of Science, Masaryk University, Kamenice 5, Building A29, 625 00, Brno, Czech Republic.
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76
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Lai AG, Aboobaker AA. EvoRegen in animals: Time to uncover deep conservation or convergence of adult stem cell evolution and regenerative processes. Dev Biol 2018; 433:118-131. [PMID: 29198565 DOI: 10.1016/j.ydbio.2017.10.010] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 10/09/2017] [Accepted: 10/10/2017] [Indexed: 01/08/2023]
Abstract
How do animals regenerate specialised tissues or their entire body after a traumatic injury, how has this ability evolved and what are the genetic and cellular components underpinning this remarkable feat? While some progress has been made in understanding mechanisms, relatively little is known about the evolution of regenerative ability. Which elements of regeneration are due to lineage specific evolutionary novelties or have deeply conserved roots within the Metazoa remains an open question. The renaissance in regeneration research, fuelled by the development of modern functional and comparative genomics, now enable us to gain a detailed understanding of both the mechanisms and evolutionary forces underpinning regeneration in diverse animal phyla. Here we review existing and emerging model systems, with the focus on invertebrates, for studying regeneration. We summarize findings across these taxa that tell us something about the evolution of adult stem cell types that fuel regeneration and the growing evidence that many highly regenerative animals harbor adult stem cells with a gene expression profile that overlaps with germline stem cells. We propose a framework in which regenerative ability broadly evolves through changes in the extent to which stem cells generated through embryogenesis are maintained into the adult life history.
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Affiliation(s)
- Alvina G Lai
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom
| | - A Aziz Aboobaker
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom.
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77
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Roles of Germline Stem Cells and Somatic Multipotent Stem Cells in Hydra Sexual Reproduction. DIVERSITY AND COMMONALITY IN ANIMALS 2018. [DOI: 10.1007/978-4-431-56609-0_7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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78
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Baumgarten S, Cziesielski MJ, Thomas L, Michell CT, Esherick LY, Pringle JR, Aranda M, Voolstra CR. Evidence for miRNA-mediated modulation of the host transcriptome in cnidarian-dinoflagellate symbiosis. Mol Ecol 2017; 27:403-418. [DOI: 10.1111/mec.14452] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 11/19/2017] [Accepted: 11/21/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Sebastian Baumgarten
- Division of Biological and Environmental Science and Engineering; Red Sea Research Center; King Abdullah University of Science and Technology; Thuwal Saudi Arabia
| | - Maha J. Cziesielski
- Division of Biological and Environmental Science and Engineering; Red Sea Research Center; King Abdullah University of Science and Technology; Thuwal Saudi Arabia
| | - Ludivine Thomas
- Bioscience Core Laboratory; King Abdullah University of Science and Technology; Thuwal Saudi Arabia
| | - Craig T. Michell
- Division of Biological and Environmental Science and Engineering; Red Sea Research Center; King Abdullah University of Science and Technology; Thuwal Saudi Arabia
| | - Lisl Y. Esherick
- Department of Genetics; Stanford University School of Medicine; Stanford CA USA
| | - John R. Pringle
- Department of Genetics; Stanford University School of Medicine; Stanford CA USA
| | - Manuel Aranda
- Division of Biological and Environmental Science and Engineering; Red Sea Research Center; King Abdullah University of Science and Technology; Thuwal Saudi Arabia
| | - Christian R. Voolstra
- Division of Biological and Environmental Science and Engineering; Red Sea Research Center; King Abdullah University of Science and Technology; Thuwal Saudi Arabia
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79
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Praher D, Zimmermann B, Genikhovich G, Columbus-Shenkar Y, Modepalli V, Aharoni R, Moran Y, Technau U. Characterization of the piRNA pathway during development of the sea anemone Nematostella vectensis. RNA Biol 2017; 14:1727-1741. [PMID: 28783426 PMCID: PMC5731801 DOI: 10.1080/15476286.2017.1349048] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 06/22/2017] [Accepted: 06/27/2017] [Indexed: 12/11/2022] Open
Abstract
PIWI-interacting RNAs (piRNAs) and associated proteins comprise a conserved pathway for silencing transposons in metazoan germlines. piRNA pathway components are also expressed in multipotent somatic stem cells in various organisms. piRNA functions have been extensively explored in bilaterian model systems, however, comprehensive studies in non-bilaterian phyla remain limited. Here we investigate the piRNA pathway during the development of Nematostella vectensis, a well-established model system belonging to Cnidaria, the sister group to Bilateria. To date, no population of somatic stem cells has been identified in this organism, despite its long life-span and regenerative capacities that require a constant cell-renewal. We show that Nematostella piRNA pathway components are broadly expressed in early developmental stages, while piRNAs themselves show differential expression, suggesting specific developmental roles of distinct piRNA families. In adults, piRNA associated proteins are enriched in the germline but also expressed in somatic cells, indicating putative stem cell properties. Furthermore, we provide experimental evidence that Nematostella piRNAs cleave transposable elements as well as protein-coding genes. Our results demonstrate that somatic expression of piRNA associated proteins as well as the roles of piRNAs in transposon repression and gene regulation are likely ancestral features that evolved before the split between Cnidaria and Bilateria.
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Affiliation(s)
- Daniela Praher
- Department of Molecular Evolution and Development; Centre of Organismal Systems Biology, Faculty of Life Sciences, University of Vienna; Althanstrasse 14, Wien, Austria
| | - Bob Zimmermann
- Department of Molecular Evolution and Development; Centre of Organismal Systems Biology, Faculty of Life Sciences, University of Vienna; Althanstrasse 14, Wien, Austria
| | - Grigory Genikhovich
- Department of Molecular Evolution and Development; Centre of Organismal Systems Biology, Faculty of Life Sciences, University of Vienna; Althanstrasse 14, Wien, Austria
| | - Yaara Columbus-Shenkar
- Department of Ecology, Evolution and Behavior; Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem; Givat Ram, Jerusalem, Israel
| | - Vengamanaidu Modepalli
- Department of Ecology, Evolution and Behavior; Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem; Givat Ram, Jerusalem, Israel
| | - Reuven Aharoni
- Department of Ecology, Evolution and Behavior; Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem; Givat Ram, Jerusalem, Israel
| | - Yehu Moran
- Department of Ecology, Evolution and Behavior; Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem; Givat Ram, Jerusalem, Israel
| | - Ulrich Technau
- Department of Molecular Evolution and Development; Centre of Organismal Systems Biology, Faculty of Life Sciences, University of Vienna; Althanstrasse 14, Wien, Austria
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80
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Holz A, Streit A. Gain and Loss of Small RNA Classes-Characterization of Small RNAs in the Parasitic Nematode Family Strongyloididae. Genome Biol Evol 2017; 9:2826-2843. [PMID: 29036592 PMCID: PMC5737618 DOI: 10.1093/gbe/evx197] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2017] [Indexed: 12/24/2022] Open
Abstract
The nematode family Strongyloididae is of particular interest because it contains important parasites of medical and veterinary relevance. In addition, species of this family can form parasitic and free-living generations and it also occupies an interesting phylogenetic position within the nematodes. Nematodes differ in several ways from other taxa with respect to their small noncoding RNAs. Recent comparative studies revealed that there is also considerable variability within the nematodes. However, no Strongyloididae species or close relative was included in these studies. We characterized the small RNAs of two developmental stages of three different Strongyloididae species and compared them with the well-studied free-living nematodes Caenorhabditis elegans and Pristionchus pacificus. Strongyloididae have conserved and taxon-specific microRNAs, many of which are differentially regulated between the two developmental stages. We identified a novel class of around 27-nucleotide-long RNAs starting with 5'G or A, of which a large fraction have the potential to target transposable elements. These RNAs most likely have triphosphates at their 5' ends and are therefore presumably synthesized by RNA-dependent RNA polymerases. In contrast to C. elegans but similarly to some other nematode taxa, Strongyloididae have no Piwi-interacting RNAs, nor do their genomes encode Argonaute proteins of the Piwi family. Finally, we attempted but failed to detect circulating parasite small RNAs in the blood of hosts.
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Affiliation(s)
- Anja Holz
- Department of Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Adrian Streit
- Department of Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
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81
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Ninova M, Griffiths-Jones S, Ronshaugen M. Abundant expression of somatic transposon-derived piRNAs throughout Tribolium castaneum embryogenesis. Genome Biol 2017; 18:184. [PMID: 28950880 PMCID: PMC5613491 DOI: 10.1186/s13059-017-1304-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 08/18/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Piwi-interacting RNAs (piRNAs) are a class of short (~26-31-nucleotide) non-protein-coding RNAs expressed in the metazoan germline. The piRNA pathway in arthropods is best understood in the ovary of Drosophila melanogaster, where it acts to silence active transposable elements (TEs). Maternal loading of piRNAs in oocytes is further required for the inheritance of piRNA-mediated transposon defence. However, our understanding of the diversity, evolution and function of the piRNA complement beyond drosophilids is limited. The red flour beetle, Tribolium castaneum, is an emerging model organism separated from Drosophila by ~ 350 million years of evolution that displays a number of features ancestral to arthropods, including short germ embryogenesis. Here, we characterize the maternally deposited and zygotically expressed small RNA and mRNA complements throughout T. castaneum embryogenesis. RESULTS We find that beetle oocytes and embryos of all stages are abundant in heterogeneous ~ 28-nucleotide RNAs. These small RNAs originate from discrete genomic loci enriched in TE sequences and display the molecular signatures of transposon-derived piRNAs. In addition to the maternally loaded primary piRNAs, Tribolium embryos produce secondary piRNAs by the cleavage of zygotically activated TE transcripts via the ping-pong mechanism. The two Tribolium piRNA pathway effector proteins, Tc-Piwi/Aub and Tc-Ago3, are also expressed throughout the soma of early embryos. CONCLUSIONS Our results show that the piRNA pathway in Tribolium is not restricted to the germline, but also operates in the embryo and may act to antagonize zygotically activated transposons. Taken together, these data highlight a functional divergence of the piRNA pathway between insects.
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Affiliation(s)
- Maria Ninova
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E California Blvd, Pasadena, CA, 91125, USA
| | - Sam Griffiths-Jones
- Faculty of Biology, Medicine and Health, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.
| | - Matthew Ronshaugen
- Faculty of Biology, Medicine and Health, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.
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82
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Sahu S, Dattani A, Aboobaker AA. Secrets from immortal worms: What can we learn about biological ageing from the planarian model system? Semin Cell Dev Biol 2017; 70:108-121. [PMID: 28818620 DOI: 10.1016/j.semcdb.2017.08.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 08/07/2017] [Accepted: 08/09/2017] [Indexed: 12/12/2022]
Abstract
Understanding how some animals are immortal and avoid the ageing process is important. We currently know very little about how they achieve this. Research with genetic model systems has revealed the existence of conserved genetic pathways and molecular processes that affect longevity. Most of these established model organisms have relatively short lifespans. Here we consider the use of planarians, with an immortal life-history that is able to entirely avoid the ageing process. These animals are capable of profound feats of regeneration fueled by a population of adult stem cells called neoblasts. These cells are capable of indefinite self-renewal that has underpinned the evolution of animals that reproduce only by fission, having disposed of the germline, and must therefore be somatically immortal and avoid the ageing process. How they do this is only now starting to be understood. Here we suggest that the evidence so far supports the hypothesis that the lack of ageing is an emergent property of both being highly regenerative and the evolution of highly effective mechanisms for ensuring genome stability in the neoblast stem cell population. The details of these mechanisms could prove to be very informative in understanding how the causes of ageing can be avoided, slowed or even reversed.
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Affiliation(s)
- Sounak Sahu
- Department of Zoology, South Parks Road, University of Oxford, Oxford OX1 3PS, UK
| | - Anish Dattani
- Department of Zoology, South Parks Road, University of Oxford, Oxford OX1 3PS, UK
| | - A Aziz Aboobaker
- Department of Zoology, South Parks Road, University of Oxford, Oxford OX1 3PS, UK.
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83
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Spina EJ, Guzman E, Zhou H, Kosik KS, Smith WC. A microRNA-mRNA expression network during oral siphon regeneration in Ciona. Development 2017; 144:1787-1797. [PMID: 28432214 DOI: 10.1242/dev.144097] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 04/10/2017] [Indexed: 12/14/2022]
Abstract
Here we present a parallel study of mRNA and microRNA expression during oral siphon (OS) regeneration in Ciona robusta, and the derived network of their interactions. In the process of identifying 248 mRNAs and 15 microRNAs as differentially expressed, we also identified 57 novel microRNAs, several of which are among the most highly differentially expressed. Analysis of functional categories identified enriched transcripts related to stress responses and apoptosis at the wound healing stage, signaling pathways including Wnt and TGFβ during early regrowth, and negative regulation of extracellular proteases in late stage regeneration. Consistent with the expression results, we found that inhibition of TGFβ signaling blocked OS regeneration. A correlation network was subsequently inferred for all predicted microRNA-mRNA target pairs expressed during regeneration. Network-based clustering associated transcripts into 22 non-overlapping groups, the functional analysis of which showed enrichment of stress response, signaling pathway and extracellular protease categories that could be related to specific microRNAs. Predicted targets of the miR-9 cluster suggest a role in regulating differentiation and the proliferative state of neural progenitors through regulation of the cytoskeleton and cell cycle.
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Affiliation(s)
- Elijah J Spina
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Elmer Guzman
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Hongjun Zhou
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Kenneth S Kosik
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - William C Smith
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA .,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
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84
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Song S, Yu H, Li Q. Genome survey and characterization of reproduction-related genes in the Pacific oyster. INVERTEBR REPROD DEV 2017. [DOI: 10.1080/07924259.2017.1287780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Shanshan Song
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao, China
| | - Hong Yu
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao, China
| | - Qi Li
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao, China
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85
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Sivagurunathan S, Palanisamy K, Arunachalam JP, Chidambaram S. Possible role of HIWI2 in modulating tight junction proteins in retinal pigment epithelial cells through Akt signaling pathway. Mol Cell Biochem 2016; 427:145-156. [DOI: 10.1007/s11010-016-2906-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 12/03/2016] [Indexed: 12/22/2022]
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86
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A somatic piRNA pathway in the Drosophila fat body ensures metabolic homeostasis and normal lifespan. Nat Commun 2016; 7:13856. [PMID: 28000665 PMCID: PMC5187580 DOI: 10.1038/ncomms13856] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 11/04/2016] [Indexed: 01/11/2023] Open
Abstract
In gonadal tissues, the Piwi-interacting (piRNA) pathway preserves genomic integrity by employing 23–29 nucleotide (nt) small RNAs complexed with argonaute proteins to suppress parasitic mobile sequences of DNA called transposable elements (TEs). Although recent evidence suggests that the piRNA pathway may be present in select somatic cells outside the gonads, the role of a non-gonadal somatic piRNA pathway is not well characterized. Here we report a functional somatic piRNA pathway in the adult Drosophila fat body including the presence of the piRNA effector protein Piwi and canonical 23–29 nt long TE-mapping piRNAs. The piwi mutants exhibit depletion of fat body piRNAs, increased TE mobilization, increased levels of DNA damage and reduced lipid stores. These mutants are starvation sensitive, immunologically compromised and short-lived, all phenotypes associated with compromised fat body function. These findings demonstrate the presence of a functional non-gonadal somatic piRNA pathway in the adult fat body that affects normal metabolism and overall organismal health.
The Piwi-interacting RNA (piRNA) pathway is known to suppress transposable elements in gonadal tissues. Here the authors provide evidence for a functional piRNA pathway in the somatic cells of the Drosophila fat body with roles in metabolism, immunological function and overall health.
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87
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Rodrigues M, Ostermann T, Kremeser L, Lindner H, Beisel C, Berezikov E, Hobmayer B, Ladurner P. Profiling of adhesive-related genes in the freshwater cnidarian Hydra magnipapillata by transcriptomics and proteomics. BIOFOULING 2016; 32:1115-1129. [PMID: 27661452 PMCID: PMC5080974 DOI: 10.1080/08927014.2016.1233325] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 09/01/2016] [Indexed: 06/06/2023]
Abstract
The differentiated ectodermal basal disc cells of the freshwater cnidarian Hydra secrete proteinaceous glue to temporarily attach themselves to underwater surfaces. Using transcriptome sequencing and a basal disc-specific RNA-seq combined with in situ hybridisation a highly specific set of candidate adhesive genes was identified. A de novo transcriptome assembly of 55,849 transcripts (>200 bp) was generated using paired-end and single reads from Illumina libraries constructed from different polyp conditions. Differential transcriptomics and spatial gene expression analysis by in situ hybridisation allowed the identification of 40 transcripts exclusively expressed in the ectodermal basal disc cells. Comparisons after mass spectrometry analysis of the adhesive secretion showed a total of 21 transcripts to be basal disc specific and eventually secreted through basal disc cells. This is the first study to survey adhesion-related genes in Hydra. The candidate list presented in this study provides a platform for unravelling the molecular mechanism of underwater adhesion of Hydra.
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Affiliation(s)
- Marcelo Rodrigues
- Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Thomas Ostermann
- Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Leopold Kremeser
- Division of Clinical Biochemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Herbert Lindner
- Division of Clinical Biochemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | | | - Eugene Berezikov
- ERIBA, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Bert Hobmayer
- Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Peter Ladurner
- Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
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88
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Neuhof M, Levin M, Rechavi O. Vertically- and horizontally-transmitted memories - the fading boundaries between regeneration and inheritance in planaria. Biol Open 2016; 5:1177-88. [PMID: 27565761 PMCID: PMC5051648 DOI: 10.1242/bio.020149] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The Weismann barrier postulates that genetic information passes only from the germline to the soma and not in reverse, thus providing an obstacle to the inheritance of acquired traits. Certain organisms such as planaria – flatworms that can reproduce through asymmetric fission – avoid the limitations of this barrier, thus blurring the distinction between the processes of inheritance and development. In this paper, we re-evaluate canonical ideas about the interaction between developmental, genetic and evolutionary processes through the lens of planaria. Biased distribution of epigenetic effects in asymmetrically produced parts of a regenerating organism could increase variation and therefore affect the species' evolution. The maintenance and fixing of somatic experiences, encoded via stable biochemical or physiological states, may contribute to evolutionary processes in the absence of classically defined generations. We discuss different mechanisms that could induce asymmetry between the two organisms that eventually develop from the regenerating parts, including one particularly fascinating source – the potential capacity of the brain to produce long-lasting epigenetic changes. Summary: In this hypothesis paper we re-evaluate canonical ideas about the interaction between developmental, genetic and evolutionary processes through the lens of planaria, an invertebrate model organism which challenges fundamental assumptions regarding reproduction.
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Affiliation(s)
- Moran Neuhof
- Department of Neurobiology, Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Michael Levin
- Allen Discovery Center, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155, USA
| | - Oded Rechavi
- Department of Neurobiology, Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel Allen Discovery Center, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155, USA Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
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89
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Siebert S, Juliano CE. Sex, polyps, and medusae: Determination and maintenance of sex in cnidarians. Mol Reprod Dev 2016; 84:105-119. [DOI: 10.1002/mrd.22690] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 08/10/2016] [Indexed: 01/22/2023]
Affiliation(s)
- Stefan Siebert
- Department of Molecular and Cellular Biology; University of California; Davis California
| | - Celina E. Juliano
- Department of Molecular and Cellular Biology; University of California; Davis California
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90
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Gehrke AR, Srivastava M. Neoblasts and the evolution of whole-body regeneration. Curr Opin Genet Dev 2016; 40:131-137. [PMID: 27498025 DOI: 10.1016/j.gde.2016.07.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Revised: 07/02/2016] [Accepted: 07/13/2016] [Indexed: 11/26/2022]
Abstract
The molecular mechanisms underlying whole-body regeneration are best understood in the planarian flatworm Schmidtea mediterranea, where a heterogeneous population of somatic stem cells called neoblasts provides new tissue for regeneration of essentially any missing body part. Studies on Schmidtea have provided a detailed description of neoblasts and their role in regeneration, but comparatively little is known about the evolutionary history of these cells and their underlying developmental programs. Acoels, an understudied group of aquatic worms that are also capable of extensive whole-body regeneration, have arisen as an attractive group to study the evolution of regenerative processes due to their phylogenetically distant position relative to flatworms. Here, we review the phylogenetic distribution of neoblast cells and compare their anatomical locations, transcriptional profiles, and roles during regeneration in flatworms and acoels to understand the evolution of whole-body regeneration. While the general role of neoblasts appears conserved in species separated by 550 million years of evolution, the extrinsic inputs they receive during regeneration can vary, making the distinction between homology and convergence of mechanism unclear. A more detailed understanding of the precise mechanisms behind whole-body regeneration in diverse phyla is necessary to understand the evolutionary history of this powerful process.
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Affiliation(s)
- Andrew R Gehrke
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Mansi Srivastava
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.
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91
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Reitzel AM, Pang K, Martindale MQ. Developmental expression of "germline"- and "sex determination"-related genes in the ctenophore Mnemiopsis leidyi. EvoDevo 2016; 7:17. [PMID: 27489613 PMCID: PMC4971632 DOI: 10.1186/s13227-016-0051-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 07/07/2016] [Indexed: 02/04/2023] Open
Abstract
Background An essential developmental pathway in sexually reproducing animals is the specification of germ cells and the differentiation of mature gametes, sperm and oocytes. The “germline” genes vasa, nanos and piwi are commonly identified in primordial germ cells, suggesting a molecular signature for the germline throughout animals. However, these genes are also expressed in a diverse set of somatic stem cells throughout the animal kingdom leaving open significant questions for whether they are required for germline specification. Similarly, members of the Dmrt gene family are essential components regulating sex determination and differentiation in bilaterian animals, but the functions of these transcription factors, including potential roles in sex determination, in early diverging animals remain unknown. The phylogenetic position of ctenophores and the genome sequence of the lobate Mnemiopsisleidyi motivated us to determine the compliment of these gene families in this species and determine expression patterns during development. Results Our phylogenetic analyses of the vasa, piwi and nanos gene families show that Mnemiopsis has multiple genes in each family with multiple lineage-specific paralogs. Expression domains of Mnemiopsis nanos, vasa and piwi, during embryogenesis from fertilization to the cydippid stage, were diverse, with little overlapping expression and no or little expression in what we think are the germ cells or gametogenic regions. piwi paralogs in Mnemiopsis had distinct expression domains in the ectoderm during development. We observed overlapping expression domains in the apical organ and tentacle apparatus of the cydippid for a subset of “germline genes,” which are areas of high cell proliferation, suggesting that these genes are involved with “stem cell” specification and maintenance. Similarly, the five Dmrt genes show diverse non-overlapping expression domains, with no clear evidence for expression in future gametogenic regions of the adult. We also report on splice variants for two Mnemiopsis Dmrt genes that impact the presence and composition of the DM DNA binding domain for these transcription factors. Conclusion Our results are consistent with a potential role for vasa, piwi and nanos genes in the specification or maintenance of somatic stem cell populations during development in Mnemiopsis. These results are similar to previous results in the tentaculate ctenophore Pleurobrachia, with the exception that these genes were also expressed in gonads and developing gametes of adult Pleurobrachia. These differences suggest that the Mnemiopsis germline is either specified later in development than hypothesized, the germline undergoes extensive migration, or the germline does not express these classic molecular markers. Our results highlight the utility of comparing expression of orthologous genes across multiple species. We provide the first description of Dmrt expression in a ctenophore, which indicates that Dmrt genes are expressed in distinct structures and regions during development but not in future gametogenic regions, the only sex-specific structure for this hermaphroditic species. Electronic supplementary material The online version of this article (doi:10.1186/s13227-016-0051-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adam M Reitzel
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC USA
| | - Kevin Pang
- Sars International Centre for Marine Molecular Biology, Thormøhlensgt. 55, 5008 Bergen, Norway
| | - Mark Q Martindale
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL USA
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92
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Leclère L, Copley RR, Momose T, Houliston E. Hydrozoan insights in animal development and evolution. Curr Opin Genet Dev 2016; 39:157-167. [DOI: 10.1016/j.gde.2016.07.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 06/02/2016] [Accepted: 07/07/2016] [Indexed: 12/21/2022]
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93
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Abstract
The evolution of multicellular animals has been attributed to many kinds of selective advantage; here I suggest that the evolution of somatic cells to feed and protect the germline was central to the appearance of animals. This would have been driven by selection for extreme anisogamy--the evolution of sperm and egg. Evidence is adduced from the germline stem cells of simple animals (defining germline as any cell that normally produces the next generation via the sexual process) and from the control circuitry ubiquitous in animal germlines. With the soma and its elaboration came animal development, as we understand it.
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Affiliation(s)
- Hugh R Woodland
- School of Life Sciences, University of Warwick, Coventry, United Kingdom.
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94
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Abstract
Stem cells are pivotal for development and tissue homeostasis of multicellular animals, and the quest for a gene toolkit associated with the emergence of stem cells in a common ancestor of all metazoans remains a major challenge for evolutionary biology. We reconstructed the conserved gene repertoire of animal stem cells by transcriptomic profiling of totipotent archeocytes in the demosponge Ephydatia fluviatilis and by tracing shared molecular signatures with flatworm and Hydra stem cells. Phylostratigraphy analyses indicated that most of these stem-cell genes predate animal origin, with only few metazoan innovations, notably including several partners of the Piwi machinery known to promote genome stability. The ancestral stem-cell transcriptome is strikingly poor in transcription factors. Instead, it is rich in RNA regulatory actors, including components of the "germ-line multipotency program" and many RNA-binding proteins known as critical regulators of mammalian embryonic stem cells.
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95
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Epigenetics and Shared Molecular Processes in the Regeneration of Complex Structures. Stem Cells Int 2015; 2016:6947395. [PMID: 26681954 PMCID: PMC4670690 DOI: 10.1155/2016/6947395] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 05/30/2015] [Indexed: 12/27/2022] Open
Abstract
The ability to regenerate complex structures is broadly represented in both plant and animal kingdoms. Although regenerative abilities vary significantly amongst metazoans, cumulative studies have identified cellular events that are broadly observed during regenerative events. For example, structural damage is recognized and wound healing initiated upon injury, which is followed by programmed cell death in the vicinity of damaged tissue and a burst in proliferation of progenitor cells. Sustained proliferation and localization of progenitor cells to site of injury give rise to an assembly of differentiating cells known as the regeneration blastema, which fosters the development of new tissue. Finally, preexisting tissue rearranges and integrates with newly differentiated cells to restore proportionality and function. While heterogeneity exists in the basic processes displayed during regenerative events in different species—most notably the cellular source contributing to formation of new tissue—activation of conserved molecular pathways is imperative for proper regulation of cells during regeneration. Perhaps the most fundamental of such molecular processes entails chromatin rearrangements, which prime large changes in gene expression required for differentiation and/or dedifferentiation of progenitor cells. This review provides an overview of known contributions to regenerative processes by noncoding RNAs and chromatin-modifying enzymes involved in epigenetic regulation.
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96
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Chirn GW, Rahman R, Sytnikova YA, Matts JA, Zeng M, Gerlach D, Yu M, Berger B, Naramura M, Kile BT, Lau NC. Conserved piRNA Expression from a Distinct Set of piRNA Cluster Loci in Eutherian Mammals. PLoS Genet 2015; 11:e1005652. [PMID: 26588211 PMCID: PMC4654475 DOI: 10.1371/journal.pgen.1005652] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 10/15/2015] [Indexed: 12/18/2022] Open
Abstract
The Piwi pathway is deeply conserved amongst animals because one of its essential functions is to repress transposons. However, many Piwi-interacting RNAs (piRNAs) do not base-pair to transposons and remain mysterious in their targeting function. The sheer number of piRNA cluster (piC) loci in animal genomes and infrequent piRNA sequence conservation also present challenges in determining which piC loci are most important for development. To address this question, we determined the piRNA expression patterns of piC loci across a wide phylogenetic spectrum of animals, and reveal that most genic and intergenic piC loci evolve rapidly in their capacity to generate piRNAs, regardless of known transposon silencing function. Surprisingly, we also uncovered a distinct set of piC loci with piRNA expression conserved deeply in Eutherian mammals. We name these loci Eutherian-Conserved piRNA cluster (ECpiC) loci. Supporting the hypothesis that conservation of piRNA expression across ~100 million years of Eutherian evolution implies function, we determined that one ECpiC locus generates abundant piRNAs antisense to the STOX1 transcript, a gene clinically associated with preeclampsia. Furthermore, we confirmed reduced piRNAs in existing mouse mutations at ECpiC-Asb1 and -Cbl, which also display spermatogenic defects. The Asb1 mutant testes with strongly reduced Asb1 piRNAs also exhibit up-regulated gene expression profiles. These data indicate ECpiC loci may be specially adapted to support Eutherian reproduction. Animal genomes from flies to humans contain many hundreds of non-coding elements called Piwi-interacting RNAs (piRNAs) cluster loci (piC loci). Some of these elements generate piRNAs that direct the silencing of transposable elements, which are pervasive genetic parasites. However, we lack an understanding of the targeting function for the remaining bulk of piRNAs because their loci are not complementarity to transposable elements. In addition, the field does not know if all piC loci are quickly evolving, or if some piC loci might be deeply conserved in piRNA expression, an indication of its potentially functional importance. Our study confirms the highly rapid evolution in piRNA expression capacity for the majority of piC loci in flies and mammals, with many clade- and species-specific piC loci expression patterns. In spite of this, we also discover a cohort of piC loci that are deeply conserved in piRNA expression from the human to the dog, a significantly broad phylogenetic spectrum of eutherian mammals. However, this conservation in piRNA expression ends at non-eutherian mammals like marsupials and monotremes. Existing mutations in two of these Eutherian-Conserved piC (ECpiC) loci impair mouse reproduction and abrogate piRNA production. Therefore, we suggest these ECpiC loci are conserved for piRNA expression due to their important function in eutherian reproduction and stand out as prime candidates for future genetic studies.
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Affiliation(s)
- Gung-wei Chirn
- Department of Biology and Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, United States of America
| | - Reazur Rahman
- Department of Biology and Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, United States of America
| | - Yuliya A. Sytnikova
- Department of Biology and Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, United States of America
| | - Jessica A. Matts
- Department of Biology and Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, United States of America
| | - Mei Zeng
- Department of Biology and Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, United States of America
| | - Daniel Gerlach
- Research Institute of Molecular Pathology, Vienna Biocenter, Vienna, Austria
| | - Michael Yu
- Mathematics Department and Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Bonnie Berger
- Mathematics Department and Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Mayumi Naramura
- Eppley Institute, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Benjamin T. Kile
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Nelson C. Lau
- Department of Biology and Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, United States of America
- * E-mail:
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97
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Abstract
The Myxozoa comprise over 2,000 species of microscopic obligate parasites that use both invertebrate and vertebrate hosts as part of their life cycle. Although the evolutionary origin of myxozoans has been elusive, a close relationship with cnidarians, a group that includes corals, sea anemones, jellyfish, and hydroids, is supported by some phylogenetic studies and the observation that the distinctive myxozoan structure, the polar capsule, is remarkably similar to the stinging structures (nematocysts) in cnidarians. To gain insight into the extreme evolutionary transition from a free-living cnidarian to a microscopic endoparasite, we analyzed genomic and transcriptomic assemblies from two distantly related myxozoan species, Kudoa iwatai and Myxobolus cerebralis, and compared these to the transcriptome and genome of the less reduced cnidarian parasite, Polypodium hydriforme. A phylogenomic analysis, using for the first time to our knowledge, a taxonomic sampling that represents the breadth of myxozoan diversity, including four newly generated myxozoan assemblies, confirms that myxozoans are cnidarians and are a sister taxon to P. hydriforme. Estimations of genome size reveal that myxozoans have one of the smallest reported animal genomes. Gene enrichment analyses show depletion of expressed genes in categories related to development, cell differentiation, and cell-cell communication. In addition, a search for candidate genes indicates that myxozoans lack key elements of signaling pathways and transcriptional factors important for multicellular development. Our results suggest that the degeneration of the myxozoan body plan from a free-living cnidarian to a microscopic parasitic cnidarian was accompanied by extreme reduction in genome size and gene content.
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98
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Lim RSM, Kai T. A piece of the pi(e): The diverse roles of animal piRNAs and their PIWI partners. Semin Cell Dev Biol 2015; 47-48:17-31. [PMID: 26582251 DOI: 10.1016/j.semcdb.2015.10.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Small non-coding RNAs are indispensable to many biological processes. A class of endogenous small RNAs, termed PIWI-interacting RNAs (piRNAs) because of their association with PIWI proteins, has known roles in safeguarding the genome against inordinate transposon mobilization, embryonic development, and stem cell regulation, among others. This review discusses the biogenesis of animal piRNAs and their diverse functions together with their PIWI protein partners, both in the germline and in somatic cells, and highlights the evolutionarily conserved aspects of these molecular players in animal biology.
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Affiliation(s)
- Robyn S M Lim
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.
| | - Toshie Kai
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.
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99
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SINKOVICS JOSEPHG. The cnidarian origin of the proto-oncogenes NF-κB/STAT and WNT-like oncogenic pathway drives the ctenophores (Review). Int J Oncol 2015; 47:1211-29. [PMID: 26239915 PMCID: PMC4583530 DOI: 10.3892/ijo.2015.3102] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 06/26/2015] [Indexed: 01/09/2023] Open
Abstract
The cell survival pathways of the diploblastic early multicellular eukaryotic hosts contain and operate the molecular machinery resembling those of malignantly transformed individual cells of highly advanced multicellular hosts (including Homo). In the present review, the STAT/NF-κB pathway of the cnidarian Nematostella vectensis is compared with that of human tumors (malignant lymphomas, including Reed-Sternberg cells) pointing out similarities, including possible viral initiation in both cases. In the ctenophore genome and proteome, β-catenin gains intranuclear advantages due to a physiologically weak destructive complex in the cytoplasm, and lack of natural inhibitors (the dickkopfs). Thus, a scenario similar to what tumor cells initiate and achieve is presented through several constitutive loss-of-function type mutations in the destructive complex and in the elimination of inhibitors. Vice versa, malignantly transformed individual cells of advanced multicellular hosts assume pheno-genotypic resemblance to cells of unicellular or early multicellular hosts, and presumably to their ancient predecessors, by returning to the semblance of immortality and to the resumption of the state of high degree of resistance to physicochemical insults. Human leukemogenic and oncogenic pathways are presented for comparisons. The supreme bioengineers RNA/DNA complex encoded both the malignantly transformed immortal cell and the human cerebral cortex. The former generates molecules for the immortality of cellular life in the Universe. The latter invents the inhibitors of the process in order to gain control over it.
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Affiliation(s)
- JOSEPH G. SINKOVICS
- St. Joseph Hospital's Cancer Institute Affiliated with the H.L. Moffitt Comprehensive Cancer Center; Department of Molecular Medicine, The University of South Florida Morsani College of Medicine, Tampa, FL, USA
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100
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Buzgariu W, Al Haddad S, Tomczyk S, Wenger Y, Galliot B. Multi-functionality and plasticity characterize epithelial cells in Hydra. Tissue Barriers 2015; 3:e1068908. [PMID: 26716072 PMCID: PMC4681288 DOI: 10.1080/21688370.2015.1068908] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 06/23/2015] [Accepted: 06/27/2015] [Indexed: 01/09/2023] Open
Abstract
Epithelial sheets, a synapomorphy of all metazoans but porifers, are present as 2 layers in cnidarians, ectoderm and endoderm, joined at their basal side by an extra-cellular matrix named mesoglea. In the Hydra polyp, epithelial cells of the body column are unipotent stem cells that continuously self-renew and concomitantly express their epitheliomuscular features. These multifunctional contractile cells maintain homeostasis by providing a protective physical barrier, by digesting nutrients, by selecting a stable microbiota, and by rapidly closing wounds. In addition, epithelial cells are highly plastic, supporting the adaptation of Hydra to physiological and environmental changes, such as long starvation periods where survival relies on a highly dynamic autophagy flux. Epithelial cells also play key roles in developmental processes as evidenced by the organizer activity they develop to promote budding and regeneration. We propose here an integrative view of the homeostatic and developmental aspects of epithelial plasticity in Hydra.
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Affiliation(s)
- W Buzgariu
- Department of Genetics and Evolution; Institute of Genetics and Genomics in Geneva (IGe3); Faculty of Sciences; University of Geneva; Geneva, Switzerland
| | - S Al Haddad
- Department of Genetics and Evolution; Institute of Genetics and Genomics in Geneva (IGe3); Faculty of Sciences; University of Geneva; Geneva, Switzerland
| | - S Tomczyk
- Department of Genetics and Evolution; Institute of Genetics and Genomics in Geneva (IGe3); Faculty of Sciences; University of Geneva; Geneva, Switzerland
| | - Y Wenger
- Department of Genetics and Evolution; Institute of Genetics and Genomics in Geneva (IGe3); Faculty of Sciences; University of Geneva; Geneva, Switzerland
| | - B Galliot
- Department of Genetics and Evolution; Institute of Genetics and Genomics in Geneva (IGe3); Faculty of Sciences; University of Geneva; Geneva, Switzerland
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