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Skalon EK, Panyushev NV, Podgornaya OI, Smolyaninova AR, Solovyeva AI. Expression of Transposable Elements throughout the Fasciola hepatica Trematode Life Cycle. Noncoding RNA 2024; 10:39. [PMID: 39051373 PMCID: PMC11270206 DOI: 10.3390/ncrna10040039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 06/30/2024] [Accepted: 07/02/2024] [Indexed: 07/27/2024] Open
Abstract
BACKGROUND Transposable elements (TEs) are major components of eukaryotic genomes. The extensive body of evidence suggests that although they were once considered "genomic parasites", transposons and their transcripts perform specific functions, such as regulation of early embryo development. Understanding the role of TEs in such parasites as trematodes is becoming critically important. Fasciola hepatica, a parasite affecting humans and livestock, undergoes a complex life cycle in diverse environments and hosts, and knowledge about its life cycle regulation is scarce so far. METHODS We summarized the data regarding the repetitive elements in F. hepatica and conducted bulk RNA-seq analysis across its life cycle stages. TE expression profiles were analyzed, focusing on differential expression and potential homology with previously described long non-coding RNAs (lncRNAs). RESULTS Differential expression analysis revealed stage-specific TE transcription patterns, notably peaking during egg and metacercariae stages. Some TEs showed homology with known lncRNAs and contained putative transcription factor binding sites. Interestingly, TE transcription levels were highest in eggs and metacercariae compared to adults, suggesting regulatory roles in trematode life cycle transitions. CONCLUSIONS These findings suggest that TEs may play roles in regulating trematode life cycle transitions. Moreover, TE homology with lncRNAs underscores their significance in gene regulation.
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Affiliation(s)
- Elizaveta K. Skalon
- Zoological Institute, Russian Academy of Sciences, 199034 St. Petersburg, Russia;
| | | | - Olga I. Podgornaya
- Institute of Cytology, Russian Academy of Sciences, 194064 St. Petersburg, Russia; (O.I.P.); (A.R.S.)
| | - Anastasia R. Smolyaninova
- Institute of Cytology, Russian Academy of Sciences, 194064 St. Petersburg, Russia; (O.I.P.); (A.R.S.)
| | - Anna I. Solovyeva
- Zoological Institute, Russian Academy of Sciences, 199034 St. Petersburg, Russia;
- Institute of Cytology, Russian Academy of Sciences, 194064 St. Petersburg, Russia; (O.I.P.); (A.R.S.)
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Merchant M, Mata CP, Liu Y, Zhai H, Protasio AV, Modis Y. A bioactive phlebovirus-like envelope protein in a hookworm endogenous virus. SCIENCE ADVANCES 2022; 8:eabj6894. [PMID: 35544562 PMCID: PMC9094657 DOI: 10.1126/sciadv.abj6894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 03/25/2022] [Indexed: 05/02/2023]
Abstract
Endogenous viral elements (EVEs), accounting for 15% of our genome, serve as a genetic reservoir from which new genes can emerge. Nematode EVEs are particularly diverse and informative of virus evolution. We identify Atlas virus-an intact retrovirus-like EVE in the human hookworm Ancylostoma ceylanicum, with an envelope protein genetically related to GN-GC glycoproteins from the family Phenuiviridae. A cryo-EM structure of Atlas GC reveals a class II viral membrane fusion protein fold not previously seen in retroviruses. Atlas GC has the structural hallmarks of an active fusogen. Atlas GC trimers insert into membranes with endosomal lipid compositions and low pH. When expressed on the plasma membrane, Atlas GC has cell-cell fusion activity. With its preserved biological activities, Atlas GC has the potential to acquire a cellular function. Our work reveals structural plasticity in reverse-transcribing RNA viruses.
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Affiliation(s)
- Monique Merchant
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
- Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge CB2 0AW, UK
| | - Carlos P. Mata
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
- Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge CB2 0AW, UK
| | - Yangci Liu
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
- Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge CB2 0AW, UK
| | - Haoming Zhai
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
- Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge CB2 0AW, UK
| | - Anna V. Protasio
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
- Christ’s College, University of Cambridge, St Andrew’s Street, Cambridge, CB2 3BU, UK
| | - Yorgo Modis
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
- Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge CB2 0AW, UK
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3
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Filée J, Farhat S, Higuet D, Teysset L, Marie D, Thomas-Bulle C, Hourdez S, Jollivet D, Bonnivard E. Comparative genomic and transcriptomic analyses of transposable elements in polychaetous annelids highlight LTR retrotransposon diversity and evolution. Mob DNA 2021; 12:24. [PMID: 34715903 PMCID: PMC8556966 DOI: 10.1186/s13100-021-00252-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 10/08/2021] [Indexed: 11/24/2022] Open
Abstract
Background With the expansion of high throughput sequencing, we now have access to a larger number of genome-wide studies analyzing the Transposable elements (TEs) composition in a wide variety of organisms. However, genomic analyses often remain too limited in number and diversity of species investigated to study in depth the dynamics and evolutionary success of the different types of TEs among metazoans. Therefore, we chose to investigate the use of transcriptomes to describe the diversity of TEs in phylogenetically related species by conducting the first comparative analysis of TEs in two groups of polychaetes and evaluate the diversity of TEs that might impact genomic evolution as a result of their mobility. Results We present a detailed analysis of TEs distribution in transcriptomes extracted from 15 polychaetes depending on the number of reads used during assembly, and also compare these results with additional TE scans on associated low-coverage genomes. We then characterized the clades defined by 1021 LTR-retrotransposon families identified in 26 species. Clade richness was highly dependent on the considered superfamily. Copia elements appear rare and are equally distributed in only three clades, GalEa, Hydra and CoMol. Among the eight BEL/Pao clades identified in annelids, two small clades within the Sailor lineage are new for science. We characterized 17 Gypsy clades of which only 4 are new; the C-clade largely dominates with a quarter of the families. Finally, all species also expressed for the majority two distinct transcripts encoding PIWI proteins, known to be involved in control of TEs mobilities. Conclusions This study shows that the use of transcriptomes assembled from 40 million reads was sufficient to access to the diversity and proportion of the transposable elements compared to those obtained by low coverage sequencing. Among LTR-retrotransposons Gypsy elements were unequivocally dominant but results suggest that the number of Gypsy clades, although high, may be more limited than previously thought in metazoans. For BEL/Pao elements, the organization of clades within the Sailor lineage appears more difficult to establish clearly. The Copia elements remain rare and result from the evolutionary consistent success of the same three clades. Supplementary Information The online version contains supplementary material available at 10.1186/s13100-021-00252-0.
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Affiliation(s)
- Jonathan Filée
- Laboratoire Evolution, Genomes, Comportement, Ecologie CNRS, Université Paris-Sud, IRD, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Sarah Farhat
- Marine Animal Disease Laboratory, School of Marine and Atmospheric Sciences, Stony Brook University, 100 Nicolls Road, Stony Brook, NY, 11794-5000, USA
| | - Dominique Higuet
- Institut de Systématique, Evolution, Biodiversité (ISYEB) - Sorbonne Université, Muséum National d'Histoire Naturel, CNRS, EPHE, Université des Antilles, 7 quai Saint Bernard, 75252, Paris Cedex 05, France
| | - Laure Teysset
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Biologie du Développement, UMR7622, "Transgenerational Epigenetics & small RNA Biology", F-75005, Paris, France
| | - Dominique Marie
- Sorbonne Université, CNRS, UMR 7144 AD2M, Station Biologique de Roscoff, Place Georges Teissier, 29688, Roscoff, France
| | - Camille Thomas-Bulle
- Sorbonne Université, CNRS, UMR 7144 AD2M, Station Biologique de Roscoff, Place Georges Teissier, 29688, Roscoff, France
| | - Stephane Hourdez
- UMR8222 LECOB CNRS-Sorbonne Université, Observatoire Océanologique de Banyuls, 1 avenue Pierre Fabre, 66650, Banyuls-sur-Mer, France
| | - Didier Jollivet
- Sorbonne Université, CNRS, UMR 7144 AD2M, Station Biologique de Roscoff, Place Georges Teissier, 29688, Roscoff, France
| | - Eric Bonnivard
- Sorbonne Université, CNRS, UMR 7144 AD2M, Station Biologique de Roscoff, Place Georges Teissier, 29688, Roscoff, France.
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Liu G, Jiang H, Sun W, Zhang J, Chen D, Murchie AIH. The function of twister ribozyme variants in non-LTR retrotransposition in Schistosoma mansoni. Nucleic Acids Res 2021; 49:10573-10588. [PMID: 34551436 PMCID: PMC8501958 DOI: 10.1093/nar/gkab818] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 08/23/2021] [Accepted: 09/08/2021] [Indexed: 12/13/2022] Open
Abstract
The twister ribozyme is widely distributed over numerous organisms and is especially abundant in Schistosoma mansoni, but has no confirmed biological function. Of the 17 non-LTR retrotransposons known in S. mansoni, none have thus far been associated with ribozymes. Here we report the identification of novel twister variant (T-variant) ribozymes and their function in S. mansoni non-LTR retrotransposition. We show that T-variant ribozymes are located at the 5′ end of Perere-3 non-LTR retrotransposons in the S. mansoni genome. T-variant ribozymes were demonstrated to be catalytically active in vitro. In reporter constructs, T-variants were shown to cleave in vivo, and cleavage of T-variants was sufficient for the translation of downstream reporter genes. Our analysis shows that the T-variants and Perere-3 are transcribed together. Target site duplications (TSDs); markers of target-primed reverse transcription (TPRT) and footmarks of retrotransposition, are located adjacent to the T-variant cleavage site and suggest that T-variant cleavage has taken place inS. mansoni. Sequence heterogeneity in the TSDs indicates that Perere-3 retrotransposition is not site-specific. The TSD sequences contribute to the 5′ end of the terminal ribozyme helix (P1 stem). Based on these results we conclude that T-variants have a functional role in Perere-3 retrotransposition.
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Affiliation(s)
- Getong Liu
- Fudan University Pudong Medical Center, and Institutes of Biomedical Sciences, Shanghai Medical College, Key Laboratory of Medical Epigenetics and Metabolism, Fudan University, Shanghai 200032, China.,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Hengyi Jiang
- Fudan University Pudong Medical Center, and Institutes of Biomedical Sciences, Shanghai Medical College, Key Laboratory of Medical Epigenetics and Metabolism, Fudan University, Shanghai 200032, China.,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Wenxia Sun
- Fudan University Pudong Medical Center, and Institutes of Biomedical Sciences, Shanghai Medical College, Key Laboratory of Medical Epigenetics and Metabolism, Fudan University, Shanghai 200032, China.,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Jun Zhang
- Fudan University Pudong Medical Center, and Institutes of Biomedical Sciences, Shanghai Medical College, Key Laboratory of Medical Epigenetics and Metabolism, Fudan University, Shanghai 200032, China.,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Dongrong Chen
- Fudan University Pudong Medical Center, and Institutes of Biomedical Sciences, Shanghai Medical College, Key Laboratory of Medical Epigenetics and Metabolism, Fudan University, Shanghai 200032, China.,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Alastair I H Murchie
- Fudan University Pudong Medical Center, and Institutes of Biomedical Sciences, Shanghai Medical College, Key Laboratory of Medical Epigenetics and Metabolism, Fudan University, Shanghai 200032, China.,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
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Stitz M, Chaparro C, Lu Z, Olzog VJ, Weinberg CE, Blom J, Goesmann A, Grunau C, Grevelding CG. Satellite-Like W-Elements: Repetitive, Transcribed, and Putative Mobile Genetic Factors with Potential Roles for Biology and Evolution of Schistosoma mansoni. Genome Biol Evol 2021; 13:6361599. [PMID: 34469545 PMCID: PMC8490949 DOI: 10.1093/gbe/evab204] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2021] [Indexed: 12/17/2022] Open
Abstract
A large portion of animal and plant genomes consists of noncoding DNA. This part includes tandemly repeated sequences and gained attention because it offers exciting insights into genome biology. We investigated satellite-DNA elements of the platyhelminth Schistosoma mansoni, a parasite with remarkable biological features. Schistosoma mansoni lives in the vasculature of humans causing schistosomiasis, a disease of worldwide importance. Schistosomes are the only trematodes that have evolved separate sexes, and the sexual maturation of the female depends on constant pairing with the male. The schistosome karyotype comprises eight chromosome pairs, males are homogametic (ZZ) and females are heterogametic (ZW). Part of the repetitive DNA of S. mansoni are W-elements (WEs), originally discovered as female-specific satellite DNAs in the heterochromatic block of the W-chromosome. Based on new genome and transcriptome data, we performed a reanalysis of the W-element families (WEFs). Besides a new classification of 19 WEFs, we provide first evidence for stage-, sex-, pairing-, gonad-, and strain-specific/preferential transcription of WEs as well as their mobile nature, deduced from autosomal copies of full-length and partial WEs. Structural analyses suggested roles as sources of noncoding RNA-like hammerhead ribozymes, for which we obtained functional evidence. Finally, the variable WEF occurrence in different schistosome species revealed remarkable divergence. From these results, we propose that WEs potentially exert enduring influence on the biology of S. mansoni. Their variable occurrence in different strains, isolates, and species suggests that schistosome WEs may represent genetic factors taking effect on variability and evolution of the family Schistosomatidae.
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Affiliation(s)
- Maria Stitz
- Institute of Parasitology, BFS, Justus Liebig University Giessen, Giessen, Germany
| | - Cristian Chaparro
- IHPE, CNRS, IFREMER, UPVD, University Montpellier, Perpignan, France
| | - Zhigang Lu
- Institute of Parasitology, BFS, Justus Liebig University Giessen, Giessen, Germany
| | | | | | - Jochen Blom
- Bioinformatics and Systems Biology, Justus Liebig University Giessen, Germany
| | - Alexander Goesmann
- Bioinformatics and Systems Biology, Justus Liebig University Giessen, Germany
| | - Christoph Grunau
- IHPE, CNRS, IFREMER, UPVD, University Montpellier, Perpignan, France
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6
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Solovyeva A, Levakin I, Zorin E, Adonin L, Khotimchenko Y, Podgornaya O. Transposons-Based Clonal Diversity in Trematode Involves Parts of CR1 (LINE) in Eu- and Heterochromatin. Genes (Basel) 2021; 12:1129. [PMID: 34440303 PMCID: PMC8392823 DOI: 10.3390/genes12081129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/22/2021] [Accepted: 07/23/2021] [Indexed: 01/21/2023] Open
Abstract
Trematode parthenitae have long been believed to form clonal populations, but clonal diversity has been discovered in this asexual stage of the lifecycle. Clonal polymorphism in the model species Himasthla elongata has been previously described, but the source of this phenomenon remains unknown. In this work, we traced cercarial clonal diversity using a simplified amplified fragment length polymorphism (SAFLP) method and characterised the nature of fragments in diverse electrophoretic bands. The repetitive elements were identified in both the primary sequence of the H. elongata genome and in the transcriptome data. Long-interspersed nuclear elements (LINEs) and long terminal repeat retrotransposons (LTRs) were found to represent an overwhelming majority of the genome and the transposon transcripts. Most sequenced fragments from SAFLP pattern contained the reverse transcriptase (RT, ORF2) domains of LINEs, and only a few sequences belonged to ORFs of LTRs and ORF1 of LINEs. A fragment corresponding to a CR1-like (LINE) spacer region was discovered and named CR1-renegade (CR1-rng). In addition to RT-containing CR1 transcripts, we found short CR1-rng transcripts in the redia transcriptome and short contigs in the mobilome. Probes against CR1-RT and CR1-rng presented strikingly different pictures in FISH mapping, despite both being fragments of CR1. In silico data and Southern blotting indicated that CR1-rng is not tandemly organised. CR1 involvement in clonal diversity is discussed.
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Affiliation(s)
- Anna Solovyeva
- Institute of Cytology of the Russian Academy of Science, Tikhoretsky Ave 4, 194064 Saint Petersburg, Russia;
- Zoological Institute of the Russian Academy of Sciences, Universitetskaya Nab 1, 199034 Saint Petersburg, Russia;
| | - Ivan Levakin
- Zoological Institute of the Russian Academy of Sciences, Universitetskaya Nab 1, 199034 Saint Petersburg, Russia;
| | - Evgeny Zorin
- All-Russia Research Institute for Agricultural Microbiology, Pushkin 8, 196608 Saint Petersburg, Russia;
| | - Leonid Adonin
- Moscow Institute of Physics and Technology, Institutskiy per 9, 141701 Dolgoprudny, Russia;
| | - Yuri Khotimchenko
- School of Biomedicine, Far Eastern Federal University, Sukhanova St 8, 690091 Vladivostok, Russia;
| | - Olga Podgornaya
- Institute of Cytology of the Russian Academy of Science, Tikhoretsky Ave 4, 194064 Saint Petersburg, Russia;
- Department of Cytology and Histology, Saint Petersburg State University, Universitetskaya Nab 7/9, 199034 Saint Petersburg, Russia
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7
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Philippsen GS. Transposable Elements in the Genome of Human Parasite Schistosoma mansoni: A Review. Trop Med Infect Dis 2021; 6:tropicalmed6030126. [PMID: 34287380 PMCID: PMC8293314 DOI: 10.3390/tropicalmed6030126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 07/01/2021] [Accepted: 07/03/2021] [Indexed: 11/16/2022] Open
Abstract
Transposable elements (TEs) are DNA sequences able to transpose within the host genome and, consequently, influence the dynamics of evolution in the species. Among the possible effects, TEs insertions may alter the expression and coding patterns of genes, leading to genomic innovations. Gene-duplication events, resulting from DNA segmental duplication induced by TEs transposition, constitute another important mechanism that contributes to the plasticity of genomes. This review aims to cover the current knowledge regarding TEs in the genome of the parasite Schistosoma mansoni, an agent of schistosomiasis-a neglected tropical disease affecting at least 250 million people worldwide. In this context, the literature concerning TEs description and TEs impact on the genomic architecture for S. mansoni was revisited, displaying evidence of TEs influence on schistosome speciation-mediated by bursts of transposition-and in gene-duplication events related to schistosome-host coevolution processes, as well several instances of TEs contribution into the coding sequences of genes. These findings indicate the relevant role of TEs in the evolution of the S. mansoni genome.
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8
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Mota EA, de Oliveira VF, Barban do Patrocinio A, Rodrigues V, Guerra-Sá R. Detection of Schistosoma mansoni long non-coding RNAs in the infected C57BL/6 mouse liver. Exp Parasitol 2020; 222:108062. [PMID: 33383024 DOI: 10.1016/j.exppara.2020.108062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 11/09/2020] [Accepted: 12/22/2020] [Indexed: 11/26/2022]
Abstract
Long non-coding RNAs (lncRNAs) perform several types of regulatory functions and have been recently explored in the genus Schistosoma. Although sequencing and bioinformatics approaches have demonstrated the presence of hundreds of lncRNAs and microRNAs (miRNAs) in this genus, information regarding their abundance, characteristics, and potential functions linked to Schistosoma mansoni biology and parasite-host interaction is limited. Our objectives in the present study were to verify whether 15 previously identified S. mansoni lncRNAs are detectable in the host liver. In addition, we assess whether these lncRNAs are present in the S. mansoni infective form and the stages inside the definitive host. The detection of these 15 S. mansoni lncRNAs and a long terminal repeat (LTR) retrotransposon Saci 4 was performed in the eggs, cercariae, and 3.5-h schistosomula. All lncRNAs were found to be expressed in these stages; some of the lncRNAs were found in the livers of the infected C57BL/6 mice. In conclusion, S. mansoni lncRNAs were detected in host livers and quantified. Furthermore, many of the lncRNAs analyzed showed differential expression in the larval stages, indicating that they play a stage-specific regulatory role.
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Affiliation(s)
- Ester Alves Mota
- Biochemistry and Molecular Biology Laboratory, Department of Biological Sciences, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, MG, Brazil
| | - Victor Fernandes de Oliveira
- Biochemistry and Molecular Biology Laboratory, Department of Biological Sciences, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, MG, Brazil
| | - Andressa Barban do Patrocinio
- Department of Biochemistry and Immunology, Faculty of Medicine of Ribeirão Preto, Universidade de São Paulo, Vila Monte Alegre, Ribeirão Preto, SP, Brazil
| | - Vanderlei Rodrigues
- Department of Biochemistry and Immunology, Faculty of Medicine of Ribeirão Preto, Universidade de São Paulo, Vila Monte Alegre, Ribeirão Preto, SP, Brazil
| | - Renata Guerra-Sá
- Biochemistry and Molecular Biology Laboratory, Department of Biological Sciences, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, MG, Brazil.
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McCusker P, Hussain W, McVeigh P, McCammick E, Clarke NG, Robb E, McKay FM, Brophy PM, Timson DJ, Mousley A, Marks NJ, Maule AG. RNA interference dynamics in juvenile Fasciola hepatica are altered during in vitro growth and development. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2020; 14:46-55. [PMID: 32866764 PMCID: PMC7475519 DOI: 10.1016/j.ijpddr.2020.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 08/06/2020] [Accepted: 08/09/2020] [Indexed: 12/17/2022]
Abstract
For over a decade RNA interference (RNAi) has been an important molecular tool for functional genomics studies in parasitic flatworms. Despite this, our understanding of RNAi dynamics in many flatworm parasites, such as the temperate liver fluke (Fasciola hepatica), remains rudimentary. The ability to maintain developing juvenile fluke in vitro provides the opportunity to perform functional studies during development of the key pathogenic life stage. Here, we investigate the RNAi competence of developing juvenile liver fluke. Firstly, all life stages examined possess, and express, core candidate RNAi effectors encouraging the hypothesis that all life stages of F. hepatica are RNAi competent. RNAi effector analyses supported growing evidence that parasitic flatworms have evolved a separate clade of RNAi effectors with unknown function. Secondly, we assessed the impact of growth/development during in vitro culture on RNAi in F. hepatica juveniles and found that during the first week post-excystment liver fluke juveniles exhibit quantitatively lower RNAi mediated transcript knockdown when maintained in growth inducing media. This did not appear to occur in older in vitro juveniles, suggesting that rapidly shifting transcript dynamics over the first week following excystment alters RNAi efficacy after a single 24 h exposure to double stranded (ds)RNA. Finally, RNAi efficiency was found to be improved through use of a repeated dsRNA exposure methodology that has facilitated silencing of genes in a range of tissues, thereby increasing the utility of RNAi as a functional genomics tool in F. hepatica.
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Affiliation(s)
- Paul McCusker
- Microbe and Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, UK.
| | - Wasim Hussain
- Microbe and Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, UK
| | - Paul McVeigh
- Microbe and Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, UK
| | - Erin McCammick
- Microbe and Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, UK
| | - Nathan G Clarke
- Microbe and Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, UK
| | - Emily Robb
- Microbe and Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, UK
| | - Fiona M McKay
- Microbe and Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, UK
| | - Peter M Brophy
- Institute of Biological, Environmental & Rural Sciences, Aberystwyth University, Aberystwyth, UK
| | - David J Timson
- School of Pharmacy & Biomolecular Sciences, University of Brighton, Brighton, UK
| | - Angela Mousley
- Microbe and Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, UK
| | - Nikki J Marks
- Microbe and Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, UK
| | - Aaron G Maule
- Microbe and Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, UK
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10
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Philippsen GS, DeMarco R. Impact of transposable elements in the architecture of genes of the human parasite Schistosoma mansoni. Mol Biochem Parasitol 2018; 228:27-31. [PMID: 30597185 DOI: 10.1016/j.molbiopara.2018.12.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 12/06/2018] [Accepted: 12/27/2018] [Indexed: 01/26/2023]
Abstract
The parasites belonging to the genus Schistosoma are agents of schistosomiasis, a disease estimated as affecting 235 million people in the world. To better understand the structure of Schistosoma mansoni genome, transposable elements (TEs) distribution and impact on gene structures were investigated. Our analyses indicated a differential distribution of TEs throughout the gene structure. Introns located at the 5' end of the genes are less prone to display TEs and introns lacking TEs tend to be shorter. Therefore, this could be one of the factors explaining previous data showing that S. mansoni displays shorter introns near the 5' end of the genes. Identification of six genes harboring TEs in their coding region suggests a positive contribution for the evolution of proteome repertory of S. mansoni. Taken together, our data suggest significant contributions of TEs to the architecture of genes from S. mansoni.
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Affiliation(s)
- Gisele S Philippsen
- Universidade Federal do Paraná, Jandaia do Sul, Dr. Maximiano street, n. 426, Paraná, Brazil.
| | - Ricardo DeMarco
- Departamento de Física e Ciência Interdisciplinar, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil
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Boroni M, Sammeth M, Gava SG, Jorge NAN, Macedo AM, Machado CR, Mourão MM, Franco GR. Landscape of the spliced leader trans-splicing mechanism in Schistosoma mansoni. Sci Rep 2018; 8:3877. [PMID: 29497070 PMCID: PMC5832876 DOI: 10.1038/s41598-018-22093-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 02/12/2018] [Indexed: 11/09/2022] Open
Abstract
Spliced leader dependent trans-splicing (SLTS) has been described as an important RNA regulatory process that occurs in different organisms, including the trematode Schistosoma mansoni. We identified more than seven thousand putative SLTS sites in the parasite, comprising genes with a wide spectrum of functional classes, which underlines the SLTS as a ubiquitous mechanism in the parasite. Also, SLTS gene expression levels span several orders of magnitude, showing that SLTS frequency is not determined by the expression level of the target gene, but by the presence of particular gene features facilitating or hindering the trans-splicing mechanism. Our in-depth investigation of SLTS events demonstrates widespread alternative trans-splicing (ATS) acceptor sites occurring in different regions along the entire gene body, highlighting another important role of SLTS generating alternative RNA isoforms in the parasite, besides the polycistron resolution. Particularly for introns where SLTS directly competes for the same acceptor substrate with cis-splicing, we identified for the first time additional and important features that might determine the type of splicing. Our study substantially extends the current knowledge of RNA processing by SLTS in S. mansoni, and provide basis for future studies on the trans-splicing mechanism in other eukaryotes.
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Affiliation(s)
- Mariana Boroni
- Laboratório de Genética Bioquímica, Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil
- Laboratório de Bioinformática e Biologia Computacional, Coordenação de Pesquisa, Instituto Nacional de Câncer José Alencar Gomes da Silva, Rio de Janeiro, 20231-050, Brazil
| | - Michael Sammeth
- Bioinformatics in Transcriptomics and Functional Genomics (BITFUN), Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-901, Brazil
- Laboratório Nacional de Computação Científica, Petrópolis, 25651-075, Brazil
| | - Sandra Grossi Gava
- Grupo de Helmintologia e Malacologia Médica, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, 30190-009, Brazil
| | - Natasha Andressa Nogueira Jorge
- Laboratório de Bioinformática e Biologia Computacional, Coordenação de Pesquisa, Instituto Nacional de Câncer José Alencar Gomes da Silva, Rio de Janeiro, 20231-050, Brazil
| | - Andréa Mara Macedo
- Laboratório de Genética Bioquímica, Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil
| | - Carlos Renato Machado
- Laboratório de Genética Bioquímica, Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil
| | - Marina Moraes Mourão
- Grupo de Helmintologia e Malacologia Médica, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, 30190-009, Brazil.
| | - Glória Regina Franco
- Laboratório de Genética Bioquímica, Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil.
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Evolutionary characterization of Ty3/gypsy-like LTR retrotransposons in the parasitic cestode Echinococcus granulosus. Parasitology 2016; 143:1691-1702. [PMID: 27571603 DOI: 10.1017/s0031182016001499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Cyclophyllidean cestodes including Echinococcus granulosus have a smaller genome and show characteristics such as loss of the gut, a segmented body plan, and accelerated growth rate in hosts compared with other tissue-invading helminths. In an effort to address the molecular mechanism relevant to genome shrinkage, the evolutionary status of long-terminal-repeat (LTR) retrotransposons, which are known as the most potent genomic modulators, was investigated in the E. granulosus draft genome. A majority of the E. granulosus LTR retrotransposons were classified into a novel characteristic clade, named Saci-2, of the Ty3/gypsy family, while the remaining elements belonged to the CsRn1 clade of identical family. Their nucleotide sequences were heavily corrupted by frequent base substitutions and segmental losses. The ceased mobile activity of the major retrotransposons and the following intrinsic DNA loss in their inactive progenies might have contributed to decrease in genome size. Apart from the degenerate copies, a gag gene originating from a CsRn1-like element exhibited substantial evidences suggesting its domestication including a preserved coding profile and transcriptional activity, the presence of syntenic orthologues in cestodes, and selective pressure acting on the gene. To my knowledge, the endogenized gag gene is reported for the first time in invertebrates, though its biological function remains elusive.
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Anderson L, Amaral MS, Beckedorff F, Silva LF, Dazzani B, Oliveira KC, Almeida GT, Gomes MR, Pires DS, Setubal JC, DeMarco R, Verjovski-Almeida S. Schistosoma mansoni Egg, Adult Male and Female Comparative Gene Expression Analysis and Identification of Novel Genes by RNA-Seq. PLoS Negl Trop Dis 2015; 9:e0004334. [PMID: 26719891 PMCID: PMC4699917 DOI: 10.1371/journal.pntd.0004334] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/06/2015] [Indexed: 12/28/2022] Open
Abstract
Background Schistosomiasis is one of the most prevalent parasitic diseases worldwide and is a public health problem. Schistosoma mansoni is the most widespread species responsible for schistosomiasis in the Americas, Middle East and Africa. Adult female worms (mated to males) release eggs in the hepatic portal vasculature and are the principal cause of morbidity. Comparative separate transcriptomes of female and male adult worms were previously assessed with using microarrays and Serial Analysis of Gene Expression (SAGE), thus limiting the possibility of finding novel genes. Moreover, the egg transcriptome was analyzed only once with limited bacterially cloned cDNA libraries. Methodology/Principal findings To compare the gene expression of S. mansoni eggs, females, and males, we performed RNA-Seq on these three parasite forms using 454/Roche technology and reconstructed the transcriptome using Trinity de novo assembly. The resulting contigs were mapped to the genome and were cross-referenced with predicted Smp genes and H3K4me3 ChIP-Seq public data. For the first time, we obtained separate, unbiased gene expression profiles for S. mansoni eggs and female and male adult worms, identifying enriched biological processes and specific enriched functions for each of the three parasite forms. Transcripts with no match to predicted genes were analyzed for their protein-coding potential and the presence of an encoded conserved protein domain. A set of 232 novel protein-coding genes with putative functions related to reproduction, metabolism, and cell biogenesis was detected, which contributes to the understanding of parasite biology. Conclusions/Significance Large-scale RNA-Seq analysis using de novo assembly associated with genome-wide information for histone marks in the vicinity of gene models constitutes a new approach to transcriptome analysis that has not yet been explored in schistosomes. Importantly, all data have been consolidated into a UCSC Genome Browser search- and download-tool (http://schistosoma.usp.br/). This database provides new ways to explore the schistosome genome and transcriptome and will facilitate molecular research on this important parasite. Schistosomiasis is a public health problem caused by parasites of the genus Schistosoma, of which S. mansoni is the primary causative agent. The parasite has a complex life cycle; their sexual reproductive stage is dependent on female and male adult worms mating inside the mesenteric circulation of the human host, with the female releasing hundreds of eggs daily. This phase of the life cycle is responsible for the development of pathology, which is proportional to the number of eggs accumulating in the liver and intestine of the human host. Genome and transcriptome sequencing of this parasite represent important advances in schistosome research, but there is still a need for integrated analyses to better understand the biology of this parasite. In this study, we describe the first large-scale transcriptomes of eggs, and female and male adult worms, the parasite forms that are mainly responsible for the pathology of schistosomiasis. We were able to cross-reference the gene transcription regions with promoter regions, thus improving the gene annotations. Moreover, we identified the expression of novel protein-coding genes not yet described in the current genome annotation, advancing the biological knowledge regarding this parasite.
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Affiliation(s)
- Letícia Anderson
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Murilo S. Amaral
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
- Instituto Butantan, São Paulo, SP, Brazil
| | - Felipe Beckedorff
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Lucas F. Silva
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Bianca Dazzani
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Katia C. Oliveira
- Núcleo de Enteroparasitas, Centro de Parasitologia e Micologia, Instituto Adolfo Lutz, São Paulo, SP, Brazil
| | - Giulliana T. Almeida
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Monete R. Gomes
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - David S. Pires
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
- Instituto Butantan, São Paulo, SP, Brazil
| | - João C. Setubal
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
- Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Ricardo DeMarco
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil
| | - Sergio Verjovski-Almeida
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
- Instituto Butantan, São Paulo, SP, Brazil
- * E-mail:
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Wilson RA, Li XH, MacDonald S, Neves LX, Vitoriano-Souza J, Leite LCC, Farias LP, James S, Ashton PD, DeMarco R, Castro Borges W. The Schistosome Esophagus Is a 'Hotspot' for Microexon and Lysosomal Hydrolase Gene Expression: Implications for Blood Processing. PLoS Negl Trop Dis 2015; 9:e0004272. [PMID: 26642053 PMCID: PMC4671649 DOI: 10.1371/journal.pntd.0004272] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 11/10/2015] [Indexed: 11/19/2022] Open
Abstract
Background The schistosome esophagus is divided into anterior and posterior compartments, each surrounded by a dense cluster of gland cell bodies, the source of distinct secretory vesicles discharged into the lumen to initiate the processing of ingested blood. Erythrocytes are lysed in the lumen, leucocytes are tethered and killed and platelets are eliminated. We know little about the proteins secreted from the two glands that mediate these biological processes. Methodology/Principal Findings We have used subtractive RNA-Seq to characterise the complement of genes that are differentially expressed in a head preparation, compared to matched tissues from worm tails. The expression site of representative highlighted genes was then validated using whole munt in situ hybridisation (WISH). Mapping of transcript reads to the S. mansoni genome assembly using Cufflinks identified ~90 genes that were differentially expressed >fourfold in the head preparation; ~50 novel transcripts were also identified by de novo assembly using Trinity. The largest subset (27) of secreted proteins was encoded by microexon genes (MEGs), the most intense focus identified to date. Expression of three (MEGs 12, 16, 17) was confirmed in the anterior gland and five (MEGs 8.1, 9, 11, 15 and 22) in the posterior gland. The other major subset comprised nine lysosomal hydrolases (aspartyl proteases, phospholipases and palmitoyl thioesterase), again localised to the glands. Conclusions A proportion of the MEG-encoded secretory proteins can be classified by their primary structure. We have suggested testable hypotheses about how they might function, in conjunction with the lysosomal hydrolases, to mediate the biological processes that occur in the esophagus lumen. Antibodies bind to the esophageal secretions in both permissive and self-curing hosts, suggesting that the proteins represent a novel panel of untested vaccine candidates. A second major task is to identify which of them can serve as immune targets. Schistosomes feed on blood and we have previously shown that its processing begins in the esophagus, which does not act simply as a conduit. It comprises anterior and posterior compartments, each surrounded by glands that secrete proteins into the lumen. Erythrocytes are ruptured as they pass through the compartments and leucocytes are tethered and killed but blood fails to clot. We wanted to identify the proteins secreted from these glands by sequencing the transcriptomes of head and tail preparations to pinpoint those messenger RNAs predominantly or exclusively present only in the heads. We found approximately 50 such proteins, the largest group of 27 being encoded by microexon genes. A second group comprised hydrolytic enzymes that operate at an acid pH. We showed by hybridisation experiments that expression of these genes is indeed localised to either the anterior or the posterior gland. We have suggested that this complex mixture of secreted proteins act together to perform the biological processes that occur in the lumen or, in the case of O-glycosylated membrane proteins, form a protective lining coat. We now want to discover which of them can serve as immune targets in infected animal hosts.
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Affiliation(s)
- R. Alan Wilson
- Centre for Immunology and Infection, Department of Biology, University of York, Heslington, York, United Kingdom
- * E-mail:
| | - Xiao Hong Li
- Centre for Immunology and Infection, Department of Biology, University of York, Heslington, York, United Kingdom
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, People’s Republic of China
| | - Sandy MacDonald
- Genomics and Bioinformatics Laboratory, Department of Biology, University of York, Heslington, York, United Kingdom
| | - Leandro Xavier Neves
- Genomics and Bioinformatics Laboratory, Department of Biology, University of York, Heslington, York, United Kingdom
| | | | | | - Leonardo P. Farias
- Centro de Biotecnologia, Instituto Butantan, São Paulo, Brazil
- Centro de Pesquisa Gonçalo Moniz, Fundação Oswaldo Cruz (FIOCRUZ), Rua Waldemar Falcão, Salvador, Bahia, Brasil
| | - Sally James
- Genomics and Bioinformatics Laboratory, Department of Biology, University of York, Heslington, York, United Kingdom
| | - Peter D. Ashton
- Genomics and Bioinformatics Laboratory, Department of Biology, University of York, Heslington, York, United Kingdom
| | - Ricardo DeMarco
- Instituto de Física de São Carlos, Universidade de São Paulo, Sao Carlos, Brasil
| | - William Castro Borges
- Genomics and Bioinformatics Laboratory, Department of Biology, University of York, Heslington, York, United Kingdom
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15
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Koziol U, Radio S, Smircich P, Zarowiecki M, Fernández C, Brehm K. A Novel Terminal-Repeat Retrotransposon in Miniature (TRIM) Is Massively Expressed in Echinococcus multilocularis Stem Cells. Genome Biol Evol 2015; 7:2136-53. [PMID: 26133390 PMCID: PMC4558846 DOI: 10.1093/gbe/evv126] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2015] [Indexed: 12/14/2022] Open
Abstract
Taeniid cestodes (including the human parasites Echinococcus spp. and Taenia solium) have very few mobile genetic elements (MGEs) in their genome, despite lacking a canonical PIWI pathway. The MGEs of these parasites are virtually unexplored, and nothing is known about their expression and silencing. In this work, we report the discovery of a novel family of small nonautonomous long terminal repeat retrotransposons (also known as terminal-repeat retrotransposons in miniature, TRIMs) which we have named ta-TRIM (taeniid TRIM). ta-TRIMs are only the second family of TRIM elements discovered in animals, and are likely the result of convergent reductive evolution in different taxonomic groups. These elements originated at the base of the taeniid tree and have expanded during taeniid diversification, including after the divergence of closely related species such as Echinococcus multilocularis and Echinococcus granulosus. They are massively expressed in larval stages, from a small proportion of full-length copies and from isolated terminal repeats that show transcriptional read-through into downstream regions, generating novel noncoding RNAs and transcriptional fusions to coding genes. In E. multilocularis, ta-TRIMs are specifically expressed in the germinative cells (the somatic stem cells) during asexual reproduction of metacestode larvae. This would provide a developmental mechanism for insertion of ta-TRIMs into cells that will eventually generate the adult germ line. Future studies of active and inactive ta-TRIM elements could give the first clues on MGE silencing mechanisms in cestodes.
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Affiliation(s)
- Uriel Koziol
- Institute of Hygiene and Microbiology, University of Würzburg, Germany Sección Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Santiago Radio
- Laboratorio de Interacciones Moleculares, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay Departamento de Genética, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Pablo Smircich
- Laboratorio de Interacciones Moleculares, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay Departamento de Genética, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Magdalena Zarowiecki
- Parasite Genomics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Cecilia Fernández
- Cátedra de Inmunología, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Klaus Brehm
- Institute of Hygiene and Microbiology, University of Würzburg, Germany
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Structural and Population Polymorphism of RT-Like Sequences in Avian Schistosomes Trichobilharzia szidati (Platyhelminthes: Digenea: Schistosomatidae). BIOMED RESEARCH INTERNATIONAL 2015; 2015:315312. [PMID: 26114104 PMCID: PMC4465651 DOI: 10.1155/2015/315312] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 03/07/2015] [Indexed: 11/17/2022]
Abstract
Recently we developed the genus-specific markers of the avian schistosomes of the genus Trichobilharzia, the causative agents of human cercarial dermatitis. The 7 novel genome sequences of T. franki, T. regenti, and T. szidati revealed similarity with genome repeat region of African schistosome Schistosoma mansoni. In the present work we analyzed the 37 new T. szidati sequences to study intragenome variability and host specificity for the parasite from three localities of East Europe. DNAs were isolated from cercariae or single sporocysts obtained from 6 lymnaeid snails Lymnaea stagnalis and L. palustris from Belarus and Russia. All sequences formed three diverged groups, one of which consists of the sequences with multiple deletions; other groups involved two paralogous copies with stop codons and frameshift mutations. Strong association between geographical distribution and snail host specificity cannot be established. All studied sequences have homology with the reverse transcriptase domain (RT) of Penelope-like elements (PLE) of S. mansoni and S. japonicum and new members of RT family were identified. We proposed that three diverged groups RT sequences of T. szidati are results of duplication or transposition of PLE during parasite evolution. Implications of the retroelement dynamics in the life history of avian schistosomes are discussed.
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17
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The genomic proliferation of transposable elements in colonizing populations: Schistosoma mansoni in the new world. Genetica 2015; 143:287-98. [PMID: 25681233 DOI: 10.1007/s10709-015-9825-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Accepted: 02/02/2015] [Indexed: 10/24/2022]
Abstract
Transposable elements (TEs) are mobile genes with an inherent ability to move within and among genomes. Theory predicts that TEs proliferate extensively during physiological stress due to the breakdown of TE repression systems. We tested this hypothesis in Schistosoma mansoni, a widespread trematode parasite that causes the human disease schistosomiasis. According to phylogenetic analysis, S. mansoni invaded the new world during the last 500 years. We hypothesized that new world strains of S. mansoni would have more copies of TEs than old world strains due to the physiological stress associated with invasion of the new world. We quantified the copy number of six TEs (Saci-1, Saci-2 and Saci-3, Perere-1, Merlin-sm1, and SmTRC1) in the genome and the transcriptome of old world and new world strains of S. mansoni, using qPCR relative quantification. As predicted, the genomes of new world parasites contain significantly more copies of class I and class II TEs in both laboratory and field strains. However, such differences are not observed in the transcriptome suggesting that either TE silencing mechanisms have reactivated to control the expression of these elements or the presence of inactive truncated copies of TEs.
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18
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Philippsen GS, Wilson RA, DeMarco R. Accelerated evolution of schistosome genes coding for proteins located at the host-parasite interface. Genome Biol Evol 2015; 7:431-43. [PMID: 25567667 PMCID: PMC4350168 DOI: 10.1093/gbe/evu287] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Study of proteins located at the host–parasite interface in schistosomes might provide clues about the mechanisms utilized by the parasite to escape the host immune system attack. Micro-exon gene (MEG) protein products and venom allergen-like (VAL) proteins have been shown to be present in schistosome secretions or associated with glands, which led to the hypothesis that they are important components in the molecular interaction of the parasite with the host. Phylogenetic and structural analysis of genes and their transcripts in these two classes shows that recent species-specific expansion of gene number for these families occurred separately in three different species of schistosomes. Enrichment of transposable elements in MEG and VAL genes in Schistosoma mansoni provides a credible mechanism for preferential expansion of gene numbers for these families. Analysis of the ratio between synonymous and nonsynonymous substitution rates (dN/dS) in the comparison between schistosome orthologs for the two classes of genes reveals significantly higher values when compared with a set of a control genes coding for secreted proteins, and for proteins previously localized in the tegument. Additional analyses of paralog genes indicate that exposure of the protein to the definitive host immune system is a determining factor leading to the higher than usual dN/dS values in those genes. The observation that two genes encoding S. mansoni vaccine candidate proteins, known to be exposed at the parasite surface, also display similar evolutionary dynamics suggests a broad response of the parasite to evolutionary pressure imposed by the definitive host immune system.
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Affiliation(s)
- Gisele S Philippsen
- Departamento de Física e Ciência Interdisciplinar, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil
| | - R Alan Wilson
- Centre for Immunology and Infection, Department of Biology, University of York, United Kingdom
| | - Ricardo DeMarco
- Departamento de Física e Ciência Interdisciplinar, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil
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Mourão MM, Grunau C, LoVerde PT, Jones MK, Oliveira G. Recent advances in Schistosoma genomics. Parasite Immunol 2012; 34:151-62. [PMID: 22145587 DOI: 10.1111/j.1365-3024.2011.01349.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Schistosome research has entered the genomic era with the publications reporting the Schistosoma mansoni and Schistosoma japonicum genomes. Schistosome genomics is motivated by the need for new control tools. However, much can also be learned about the biology of Schistosoma, which is a tractable experimental model. In this article, we review the recent achievements in the field of schistosome research and discuss future perspectives on genomics and how it can be integrated in a usable format, on the genetic mapping and how it has improved the genome assembly and provided new research approaches, on how epigenetics provides interesting insights into the biology of the species and on new functional genomics tools that will contribute to the understanding of the function of genes, many of which are parasite- or taxon specific.
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Affiliation(s)
- M M Mourão
- Genomics and Computational Biology Group, Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz - FIOCRUZ, Belo Horizonte, MG, Brazil
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20
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Lepesant JMJ, Cosseau C, Boissier J, Freitag M, Portela J, Climent D, Perrin C, Zerlotini A, Grunau C. Chromatin structural changes around satellite repeats on the female sex chromosome in Schistosoma mansoni and their possible role in sex chromosome emergence. Genome Biol 2012; 13:R14. [PMID: 22377319 PMCID: PMC3701142 DOI: 10.1186/gb-2012-13-2-r14] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 02/13/2012] [Accepted: 02/29/2012] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND In the leuphotrochozoan parasitic platyhelminth Schistosoma mansoni, male individuals are homogametic (ZZ) whereas females are heterogametic (ZW). To elucidate the mechanisms that led to the emergence of sex chromosomes, we compared the genomic sequence and the chromatin structure of male and female individuals. As for many eukaryotes, the lower estimate for the repeat content is 40%, with an unknown proportion of domesticated repeats. We used massive sequencing to de novo assemble all repeats, and identify unambiguously Z-specific, W-specific and pseudoautosomal regions of the S. mansoni sex chromosomes. RESULTS We show that 70 to 90% of S. mansoni W and Z are pseudoautosomal. No female-specific gene could be identified. Instead, the W-specific region is composed almost entirely of 36 satellite repeat families, of which 33 were previously unknown. Transcription and chromatin status of female-specific repeats are stage-specific: for those repeats that are transcribed, transcription is restricted to the larval stages lacking sexual dimorphism. In contrast, in the sexually dimorphic adult stage of the life cycle, no transcription occurs. In addition, the euchromatic character of histone modifications around the W-specific repeats decreases during the life cycle. Recombination repression occurs in this region even if homologous sequences are present on both the Z and W chromosomes. CONCLUSION Our study provides for the first time evidence for the hypothesis that, at least in organisms with a ZW type of sex chromosomes, repeat-induced chromatin structure changes could indeed be the initial event in sex chromosome emergence.
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Affiliation(s)
- Julie M J Lepesant
- Université de Perpignan Via Domitia, CNRS, UMR 5244 Ecologie et Evolution des Interactions (2EI), 52 Avenue Paul Alduy, 66860 Perpignan Cedex, France.
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21
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Protasio AV, Tsai IJ, Babbage A, Nichol S, Hunt M, Aslett MA, De Silva N, Velarde GS, Anderson TJC, Clark RC, Davidson C, Dillon GP, Holroyd NE, LoVerde PT, Lloyd C, McQuillan J, Oliveira G, Otto TD, Parker-Manuel SJ, Quail MA, Wilson RA, Zerlotini A, Dunne DW, Berriman M. A systematically improved high quality genome and transcriptome of the human blood fluke Schistosoma mansoni. PLoS Negl Trop Dis 2012; 6:e1455. [PMID: 22253936 PMCID: PMC3254664 DOI: 10.1371/journal.pntd.0001455] [Citation(s) in RCA: 320] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 11/13/2011] [Indexed: 12/20/2022] Open
Abstract
Schistosomiasis is one of the most prevalent parasitic diseases, affecting millions of people in developing countries. Amongst the human-infective species, Schistosoma mansoni is also the most commonly used in the laboratory and here we present the systematic improvement of its draft genome. We used Sanger capillary and deep-coverage Illumina sequencing from clonal worms to upgrade the highly fragmented draft 380 Mb genome to one with only 885 scaffolds and more than 81% of the bases organised into chromosomes. We have also used transcriptome sequencing (RNA-seq) from four time points in the parasite's life cycle to refine gene predictions and profile their expression. More than 45% of predicted genes have been extensively modified and the total number has been reduced from 11,807 to 10,852. Using the new version of the genome, we identified trans-splicing events occurring in at least 11% of genes and identified clear cases where it is used to resolve polycistronic transcripts. We have produced a high-resolution map of temporal changes in expression for 9,535 genes, covering an unprecedented dynamic range for this organism. All of these data have been consolidated into a searchable format within the GeneDB (www.genedb.org) and SchistoDB (www.schistodb.net) databases. With further transcriptional profiling and genome sequencing increasingly accessible, the upgraded genome will form a fundamental dataset to underpin further advances in schistosome research. Schistosomiasis is a disease caused by parasitic blood flukes of the genus Schistosoma. Human-infective species are prevalent in developing countries, where they represent a major disease burden as well as an impediment to socioeconomic development. In addition to its clinical relevance, Schistosoma mansoni is the species most widely used for laboratory experimentation. In 2009, the first draft of the S. mansoni and S. japonicum genomes were published. Both genome sequences represented a great step forward for schistosome research, but their highly fragmented nature compromised the quality of potential downstream analyses. In this study, we have substantially improved both the genome and the transcriptome resources for S. mansoni. We collated existing data and added deep DNA sequence data from clonal worms and RNA sequence data from four key time points in the life cycle of the parasite. We were able to identify transcribed regions to single-base resolution and have profiled gene expression from the free-living larvae to the early human parasitic stage. We uncovered extensive use of single transcripts from multiple genes, which the organism subsequently resolves by trans-splicing. All data from this study comprise a major new release of the genome, which is publicly and easily accessible.
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Affiliation(s)
- Anna V Protasio
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, United Kingdom
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Abstract
BACKGROUND Long terminal repeat (LTR) retrotransposons are a widespread kind of transposable element present in eukaryotic genomes. They are a major factor in genome evolution due to their ability to create large scale mutations and genome rearrangements. Compared to other transposable elements, little attention has been paid to elements belonging to the metazoan BEL/Pao subclass of LTR retrotransposons. No comprehensive characterization of these elements is available so far. The aim of this study was to describe all BEL/Pao elements in a set of 62 sequenced metazoan genomes, and to analyze their phylogenetic relationship. RESULTS We identified a total of 7,861 BEL/Pao elements in 53 of our 62 study genomes. We identified BEL/Pao elements in 20 genomes where such elements had not been found so far. Our analysis shows that BEL/Pao elements are the second-most abundant class of LTR retrotransposons in the genomes we study, more abundant than Ty1/Copia elements, and second only to Ty3/Gypsy elements. They occur in multiple phyla, including basal metazoan phyla, suggesting that BEL/Pao elements arose early in animal evolution. We confirm findings from previous studies that BEL/Pao elements do not occur in mammals. The elements we found can be grouped into more than 1725 families, 1623 of which are new, previously unknown families. These families fall into seven superfamilies, only five of which have been characterized so far. One new superfamily is a major subdivision of the Pao superfamily which we propose to call Dan, because it is restricted to the genome of the zebrafish Danio rerio. The other new superfamily comprises 83 elements and is restricted to lower aquatic eumetazoans. We propose to call this superfamily Flow. BEL/Pao elements do not show any signs of recent horizontal gene transfer between distantly related species. CONCLUSIONS In sum, our analysis identifies thousands of new BEL/Pao elements and provides new insights into their distribution, abundance, and evolution.
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Xiang H, Pan G, Zhang R, Xu J, Li T, Li W, Zhou Z, Xiang Z. Natural selection maintains the transcribed LTR retrotransposons in Nosema bombycis. J Genet Genomics 2010; 37:305-14. [PMID: 20513631 DOI: 10.1016/s1673-8527(09)60048-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2010] [Revised: 03/30/2010] [Accepted: 04/20/2010] [Indexed: 11/19/2022]
Abstract
Eight intact LTR retrotransposons (Nbr1-Nbr8) have been previously characterized from the genome of Nosema bombycis, a eukaryotic parasite with a compact and reduced genome. Here we describe six novel transcribed Nbr elements (Nbr9-Nbr14) identified through either cDNA library or RT-PCR. Like previously determined ones, all of them belong to the Ty3/Gypsy superfamily. Retrotransposon diversity and incomplete domains with insertions (Nbr12), deletions (Nbr11) and in-frame stop codons in coding regions (Nbr9) were detected, suggesting that both defective and loss events of LTR retrotransposon have happened in N. bombycis genome. Analysis of selection showed that strong purifying selection acts on all elements except Nbr11. This implies that selective pressure keeps both these Nbrs and their functions in genome. Interestingly, Nbr11 is under positive selection and some positively selected codons were identified, indicating that new functionality might have evolved in the Nbr11 retrotransposon. Unlike other transposable elements, Nbr11 has integrated into a conserved syntenic block and probably resulted in the inversion of both flanking regions. This demonstrates that transposable element is an important factor for the reshuffling and evolution of their host genomes, and may be maintained under natural selection.
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Affiliation(s)
- Heng Xiang
- Institute of Sericulture and Systems Biology, Southwest University, Beibei, Chongqing 400715, China
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DeMarco R, Mathieson W, Manuel SJ, Dillon GP, Curwen RS, Ashton PD, Ivens AC, Berriman M, Verjovski-Almeida S, Wilson RA. Protein variation in blood-dwelling schistosome worms generated by differential splicing of micro-exon gene transcripts. Genome Res 2010; 20:1112-21. [PMID: 20606017 PMCID: PMC2909574 DOI: 10.1101/gr.100099.109] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Accepted: 05/14/2010] [Indexed: 11/24/2022]
Abstract
Schistosoma mansoni is a well-adapted blood-dwelling parasitic helminth, persisting for decades in its human host despite being continually exposed to potential immune attack. Here, we describe in detail micro-exon genes (MEG) in S. mansoni, some present in multiple copies, which represent a novel molecular system for creating protein variation through the alternate splicing of short (< or =36 bp) symmetric exons organized in tandem. Analysis of three closely related copies of one MEG family allowed us to trace several evolutionary events and propose a mechanism for micro-exon generation and diversification. Microarray experiments show that the majority of MEGs are up-regulated in life cycle stages associated with establishment in the mammalian host after skin penetration. Sequencing of RT-PCR products allowed the description of several alternate splice forms of micro-exon genes, highlighting the potential use of these transcripts to generate a complex pool of protein variants. We obtained direct evidence for the existence of such pools by proteomic analysis of secretions from migrating schistosomula and mature eggs. Whole-mount in situ hybridization and immunolocalization showed that MEG transcripts and proteins were restricted to glands or epithelia exposed to the external environment. The ability of schistosomes to produce a complex pool of variant proteins aligns them with the other major groups of blood parasites, but using a completely different mechanism. We believe that our data open a new chapter in the study of immune evasion by schistosomes, and their ability to generate variant proteins could represent a significant obstacle to vaccine development.
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Affiliation(s)
- Ricardo DeMarco
- Department of Biology, University of York, York YO10 5YW, United Kingdom.
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25
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Portela J, Grunau C, Cosseau C, Beltran S, Dantec C, Parrinello H, Boissier J. Whole-genome in-silico subtractive hybridization (WISH)--using massive sequencing for the identification of unique and repetitive sex-specific sequences: the example of Schistosoma mansoni. BMC Genomics 2010; 11:387. [PMID: 20565937 PMCID: PMC3091631 DOI: 10.1186/1471-2164-11-387] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 06/21/2010] [Indexed: 11/10/2022] Open
Abstract
Background Emerging methods of massive sequencing that allow for rapid re-sequencing of entire genomes at comparably low cost are changing the way biological questions are addressed in many domains. Here we propose a novel method to compare two genomes (genome-to-genome comparison). We used this method to identify sex-specific sequences of the human blood fluke Schistosoma mansoni. Results Genomic DNA was extracted from male and female (heterogametic) S. mansoni adults and sequenced with a Genome Analyzer (Illumina). Sequences are available at the NCBI sequence read archive http://www.ncbi.nlm.nih.gov/Traces/sra/ under study accession number SRA012151.6. Sequencing reads were aligned to the genome, and a pseudogenome composed of known repeats. Straightforward comparative bioinformatics analysis was performed to compare male and female schistosome genomes and identify female-specific sequences. We found that the S. mansoni female W chromosome contains only few specific unique sequences (950 Kb i.e. about 0.2% of the genome). The majority of W-specific sequences are repeats (10.5 Mb i.e. about 2.5% of the genome). Arbitrarily selected W-specific sequences were confirmed by PCR. Primers designed for unique and repetitive sequences allowed to reliably identify the sex of both larval and adult stages of the parasite. Conclusion Our genome-to-genome comparison method that we call "whole-genome in-silico subtractive hybridization" (WISH) allows for rapid identification of sequences that are specific for a certain genotype (e.g. the heterogametic sex). It can in principle be used for the detection of any sequence differences between isolates (e.g. strains, pathovars) or even closely related species.
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Affiliation(s)
- Julien Portela
- UMR 5244 CNRS-EPHE-UPVD, Parasitologie Fonctionnelle et Evolutive, CBETM, Université de Perpignan, Perpignan, France
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Thomas MC, Macias F, Alonso C, López MC. The biology and evolution of transposable elements in parasites. Trends Parasitol 2010; 26:350-62. [PMID: 20444649 DOI: 10.1016/j.pt.2010.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 03/30/2010] [Accepted: 04/01/2010] [Indexed: 12/19/2022]
Abstract
Transposable elements (TEs) are dynamic elements that can reshape host genomes by generating rearrangements with the potential to create or disrupt genes, to shuffle existing genes, and to modulate their patterns of expression. In the genomes of parasites that infect mammals several TEs have been identified that probably have been maintained throughout evolution due to their contribution to gene function and regulation of gene expression. This review addresses how TEs are organized, how they colonize the genomes of mammalian parasites, the functional role these elements play in parasite biology, and the interactions between these elements and the parasite genome.
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Affiliation(s)
- M Carmen Thomas
- Departamento de Biología Molecular, Instituto de Parasitología y Biomedicina López Neyra - CSIC, Parque Tecnológico de Ciencias de la Salud, 18100 Granada, Spain
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Parchman TL, Geist KS, Grahnen JA, Benkman CW, Buerkle CA. Transcriptome sequencing in an ecologically important tree species: assembly, annotation, and marker discovery. BMC Genomics 2010; 11:180. [PMID: 20233449 PMCID: PMC2851599 DOI: 10.1186/1471-2164-11-180] [Citation(s) in RCA: 341] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Accepted: 03/16/2010] [Indexed: 01/05/2023] Open
Abstract
Background Massively parallel sequencing of cDNA is now an efficient route for generating enormous sequence collections that represent expressed genes. This approach provides a valuable starting point for characterizing functional genetic variation in non-model organisms, especially where whole genome sequencing efforts are currently cost and time prohibitive. The large and complex genomes of pines (Pinus spp.) have hindered the development of genomic resources, despite the ecological and economical importance of the group. While most genomic studies have focused on a single species (P. taeda), genomic level resources for other pines are insufficiently developed to facilitate ecological genomic research. Lodgepole pine (P. contorta) is an ecologically important foundation species of montane forest ecosystems and exhibits substantial adaptive variation across its range in western North America. Here we describe a sequencing study of expressed genes from P. contorta, including their assembly and annotation, and their potential for molecular marker development to support population and association genetic studies. Results We obtained 586,732 sequencing reads from a 454 GS XLR70 Titanium pyrosequencer (mean length: 306 base pairs). A combination of reference-based and de novo assemblies yielded 63,657 contigs, with 239,793 reads remaining as singletons. Based on sequence similarity with known proteins, these sequences represent approximately 17,000 unique genes, many of which are well covered by contig sequences. This sequence collection also included a surprisingly large number of retrotransposon sequences, suggesting that they are highly transcriptionally active in the tissues we sampled. We located and characterized thousands of simple sequence repeats and single nucleotide polymorphisms as potential molecular markers in our assembled and annotated sequences. High quality PCR primers were designed for a substantial number of the SSR loci, and a large number of these were amplified successfully in initial screening. Conclusions This sequence collection represents a major genomic resource for P. contorta, and the large number of genetic markers characterized should contribute to future research in this and other pines. Our results illustrate the utility of next generation sequencing as a basis for marker development and population genomics in non-model species.
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Affiliation(s)
- Thomas L Parchman
- Department of Botany, University of Wyoming, Laramie, WY 82071, USA.
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28
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Transcriptome sequencing in an ecologically important tree species: assembly, annotation, and marker discovery. BMC Genomics 2010. [PMID: 20233449 DOI: 10.1186/1471‐2164‐11‐180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Massively parallel sequencing of cDNA is now an efficient route for generating enormous sequence collections that represent expressed genes. This approach provides a valuable starting point for characterizing functional genetic variation in non-model organisms, especially where whole genome sequencing efforts are currently cost and time prohibitive. The large and complex genomes of pines (Pinus spp.) have hindered the development of genomic resources, despite the ecological and economical importance of the group. While most genomic studies have focused on a single species (P. taeda), genomic level resources for other pines are insufficiently developed to facilitate ecological genomic research. Lodgepole pine (P. contorta) is an ecologically important foundation species of montane forest ecosystems and exhibits substantial adaptive variation across its range in western North America. Here we describe a sequencing study of expressed genes from P. contorta, including their assembly and annotation, and their potential for molecular marker development to support population and association genetic studies. RESULTS We obtained 586,732 sequencing reads from a 454 GS XLR70 Titanium pyrosequencer (mean length: 306 base pairs). A combination of reference-based and de novo assemblies yielded 63,657 contigs, with 239,793 reads remaining as singletons. Based on sequence similarity with known proteins, these sequences represent approximately 17,000 unique genes, many of which are well covered by contig sequences. This sequence collection also included a surprisingly large number of retrotransposon sequences, suggesting that they are highly transcriptionally active in the tissues we sampled. We located and characterized thousands of simple sequence repeats and single nucleotide polymorphisms as potential molecular markers in our assembled and annotated sequences. High quality PCR primers were designed for a substantial number of the SSR loci, and a large number of these were amplified successfully in initial screening. CONCLUSIONS This sequence collection represents a major genomic resource for P. contorta, and the large number of genetic markers characterized should contribute to future research in this and other pines. Our results illustrate the utility of next generation sequencing as a basis for marker development and population genomics in non-model species.
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Venancio TM, Wilson RA, Verjovski-Almeida S, DeMarco R. Bursts of transposition from non-long terminal repeat retrotransposon families of the RTE clade in Schistosoma mansoni. Int J Parasitol 2009; 40:743-9. [PMID: 20018191 DOI: 10.1016/j.ijpara.2009.11.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Revised: 11/24/2009] [Accepted: 11/25/2009] [Indexed: 11/16/2022]
Abstract
The genus Schistosoma is composed of blood flukes that infect vertebrates, from which three species are major causative agents of human schistosomiasis, a tropical disease that affects more than 200 million people. Current models of the recent evolution of Schistosoma indicate multiple events of migration and speciation from an Asian ancestral species. Transposable elements are important drivers of genome evolution and have been hypothesised to have an important role in speciation. In this work, we describe a comprehensive inventory of Schistosoma mansoni and Schistosoma japonicum retrotransposons, based on their recently published genomic data. We find a considerable difference in retrotransposon representation between the two species (22% and 13%, respectively). A large part of this difference can be attributed to higher representation of two previously described families of S. mansoni retrotransposons (SR2 and Perere-3/SR3), compared with the representation of their closest relative families in S. japonicum. A more detailed analysis suggests that these two S. mansoni families were the subject of recent bursts of transposition that were not paralleled by their S. japonicum counterparts. We hypothesise that these bursts could be a consequence of the evolutionary pressure resulting from migration of Schistosoma from Asia to Africa and their establishment in this new environment, helping both speciation and adaptation.
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Affiliation(s)
- Thiago M Venancio
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 05508-900 São Paulo, SP, Brazil
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Wiens M, Grebenjuk VA, Schröder HC, Müller IM, Müller WEG. Identification and isolation of a retrotransposon from the freshwater sponge Lubomirskia baicalensis: implication in rapid evolution of endemic sponges. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2009; 47:207-234. [PMID: 19198779 DOI: 10.1007/978-3-540-88552-8_9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Transposons are mobile genetic elements that are found in all major branches of life. Similarities to retroviruses concerning genome structure and transposition mechanism suggest a familial relationship. Transposons are important evolutionary drivers that trigger genetic changes such as genomic rearrangement, alteration of gene expression, and gene duplication. And, indeed, now more than ever the effect of transposons on genome evolution represents a dynamic field of research. Since sponges (phylum Porifera) are the phylogenetically oldest still extant metazoan taxon, the study of poriferan mobile elements contributes to the understanding of the generation of phenotypic diversity and speciation at the base of the metazoan tree of life. This work describes the analyses of the first poriferan mobile genetic element so far identified, the long terminal repeats- retrotransposon Baikalum-1 of Lubomirskia baicalensis (Demospongiae; Ceractinomorpha). Baikalum-1 embraces a continuous open reading frame, putatively coding for a polyprotein that consists of nucleo capsid, protease, reverse transcriptase, RNase H, and integrase, all proteins/ enzymes characteristic of retrotransposons. Baikalum-1 was discovered in all freshwater sponge species endemic to Lake Baikal, as well as in cosmopolitan sponge species that inhabit a Lake Baikal-feeding rivulet. However, the same cosmopolitan species sampled from lakes and rivers (Siberian and European) with no direct contact to Lake Baikal did not contain this particular mobile genetic element. Thus, Baikalum-1 is probably the result of an evolutionarily ancient retroviral infection that spread exclusively amongst Baikalian sponge species. In addition, the retro-transposon is found in the vicinity of the silicatein-A1 gene. Silicateins are cathepsin-like proteins that catalyze the synthesis of poriferan siliceous skeletal elements (spicules). In L. baicalensis, the silicatein-A1 gene is flanked by two palindroms, probably remnants of transposons that might be responsible for the emergence of four different silicatein genes, uniquely present in freshwater but not marine sponges. Adaptation of sponges to the freshwater habitat (with its significantly higher silica content compared to the marine milieu) required the ability to evolve rapidly, which could be conferred by high transpositional activity, accompanied by duplication and diversification of the ancestral silicatein gene of marine species.
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Affiliation(s)
- Matthias Wiens
- Abteilung Angewandte Molekularbiologie Universität, Institut für Physiologische Chemie, Duesbergweg 6, Mainz D-55099, Germany
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Oliveira G, Franco G, Verjovski-Almeida S. The Brazilian contribution to the study of the Schistosoma mansoni transcriptome. Acta Trop 2008; 108:179-82. [PMID: 18554565 DOI: 10.1016/j.actatropica.2008.04.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 12/12/2007] [Accepted: 04/28/2008] [Indexed: 10/22/2022]
Abstract
Brazilian scientists have made definitive contributions towards the understanding of the transcriptome of Schistosoma mansoni. The transcriptome, as a collection of expressed genes, was studied with two basic approaches, the sequencing of cloned cDNA ends and the production and sequencing of random fragments of cDNA. The data that was generated covers nearly the entire set of transcribed genes. These data have been important for gene discovery and annotation of gene function, annotation of the genome, construction of microarrays, identification of peptides in the study of the proteome and can be mined for splice variants, polymorphisms such as single nucleotide polymorphisms and microsatellites, for example. This review will describe the advances achieved with the contribution of Brazilian researchers to the understanding of the transcribed regions of the S. mansoni genome.
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Use of genomic DNA as an indirect reference for identifying gender-associated transcripts in morphologically identical, but chromosomally distinct, Schistosoma mansoni cercariae. PLoS Negl Trop Dis 2008; 2:e323. [PMID: 18941520 PMCID: PMC2565838 DOI: 10.1371/journal.pntd.0000323] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Accepted: 09/24/2008] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The use of DNA microarray technology to study global Schistosoma gene expression has led to the rapid identification of novel biological processes, pathways or associations. Implementation of standardized DNA microarray protocols across laboratories would assist maximal interpretation of generated datasets and extend productive application of this technology. METHODOLOGY/PRINCIPAL FINDINGS Utilizing a new Schistosoma mansoni oligonucleotide DNA microarray composed of 37,632 elements, we show that schistosome genomic DNA (gDNA) hybridizes with less variation compared to complex mixed pools of S. mansoni cDNA material (R = 0.993 for gDNA compared to R = 0.956 for cDNA during 'self versus self' hybridizations). Furthermore, these effects are species-specific, with S. japonicum or Mus musculus gDNA failing to bind significantly to S. mansoni oligonucleotide DNA microarrays (e.g R = 0.350 when S. mansoni gDNA is co-hybridized with S. japonicum gDNA). Increased median fluorescent intensities (209.9) were also observed for DNA microarray elements hybridized with S. mansoni gDNA compared to complex mixed pools of S. mansoni cDNA (112.2). Exploiting these valuable characteristics, S. mansoni gDNA was used in two-channel DNA microarray hybridization experiments as a common reference for indirect identification of gender-associated transcripts in cercariae, a schistosome life-stage in which there is no overt sexual dimorphism. This led to the identification of 2,648 gender-associated transcripts. When compared to the 780 gender-associated transcripts identified by hybridization experiments utilizing a two-channel direct method (co-hybridization of male and female cercariae cDNA), indirect methods using gDNA were far superior in identifying greater quantities of differentially expressed transcripts. Interestingly, both methods identified a concordant subset of 188 male-associated and 156 female-associated cercarial transcripts, respectively. Gene ontology classification of these differentially expressed transcripts revealed a greater diversity of categories in male cercariae. Quantitative real-time PCR analysis confirmed the DNA microarray results and supported the reliability of this platform for identifying gender-associated transcripts. CONCLUSIONS/SIGNIFICANCE Schistosome gDNA displays characteristics highly suitable for the comparison of two-channel DNA microarray results obtained from experiments conducted independently across laboratories. The schistosome transcripts identified here demonstrate, for the first time, that gender-associated patterns of expression are already well established in the morphologically identical, but chromosomally distinct, cercariae stage.
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Bae YA, Ahn JS, Kim SH, Rhyu MG, Kong Y, Cho SY. PwRn1, a novel Ty3/gypsy-like retrotransposon of Paragonimus westermani: molecular characters and its differentially preserved mobile potential according to host chromosomal polyploidy. BMC Genomics 2008; 9:482. [PMID: 18851759 PMCID: PMC2582038 DOI: 10.1186/1471-2164-9-482] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Accepted: 10/14/2008] [Indexed: 11/25/2022] Open
Abstract
Background Retrotransposons have been known to involve in the remodeling and evolution of host genome. These reverse transcribing elements, which show a complex evolutionary pathway with diverse intermediate forms, have been comprehensively analyzed from a wide range of host genomes, while the information remains limited to only a few species in the phylum Platyhelminthes. Results A LTR retrotransposon and its homologs with a strong phylogenetic affinity toward CsRn1 of Clonorchis sinensis were isolated from a trematode parasite Paragonimus westermani via a degenerate PCR method and from an insect species Anopheles gambiae by in silico analysis of the whole mosquito genome, respectively. These elements, designated PwRn1 and AgCR-1 – AgCR-14 conserved unique features including a t-RNATrp primer binding site and the unusual CHCC signature of Gag proteins. Their flanking LTRs displayed >97% nucleotide identities and thus, these elements were likely to have expanded recently in the trematode and insect genomes. They evolved heterogeneous expression strategies: a single fused ORF, two separate ORFs with an identical reading frame and two ORFs overlapped by -1 frameshifting. Phylogenetic analyses suggested that the elements with the separate ORFs had evolved from an ancestral form(s) with the overlapped ORFs. The mobile potential of PwRn1 was likely to be maintained differentially in association with the karyotype of host genomes, as was examined by the presence/absence of intergenomic polymorphism and mRNA transcripts. Conclusion Our results on the structural diversity of CsRn1-like elements can provide a molecular tool to dissect a more detailed evolutionary episode of LTR retrotransposons. The PwRn1-associated genomic polymorphism, which is substantial in diploids, will also be informative in addressing genomic diversification following inter-/intra-specific hybridization in P. westermani populations.
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Affiliation(s)
- Young-An Bae
- Department of Molecular Parasitology and Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Gyeonggi-do 440-746, Korea.
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Valentim CLL, Gomes MS, Jeremias WJ, Cunha JC, Oliveira GC, Botelho ACC, Pimenta PFP, Janotti-Passos LK, Guerra-Sá R, Babá EH. Physical localization of the retrotransposons Boudicca and Perere 03 in Schistosoma mansoni. J Parasitol 2008; 94:993-5. [PMID: 18576699 DOI: 10.1645/ge-1167.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Accepted: 12/20/2007] [Indexed: 11/10/2022] Open
Abstract
Schistosoma mansoni is 1 of the causative agents of schistosomiasis, an endemic disease in 76 countries of the world. The study of its genome, estimated to be 270 Mb, is very important to understanding schistosome biology, the mechanisms of drug resistance, and immune evasion. Repetitive elements constitute more than 40% of the S. mansoni genome and may play a role in the parasite evolution. The retrotransposons Boudicca, a long terminal repeat (LTR), and Perere 03, a non-LTR, are present in a high number in the S. mansoni genome and were localized with the use of fluorescence in situ hybridization (FISH) and primed in situ labeling (PRINS). Bacterial artificial chromosomes (BAC) clones containing the retrotransposons Boudicca and Perere 03 were selected by bioinformatic analysis and used as probes in FISH. Using metaphase chromosomes from sporocysts and the FISH and PRINS techniques, we were able to map these retrotransposons. Perere 03 was localized in the euchromatic regions of the short arm of chromosome 2 and Boudicca in the euchromatic regions of the short arm of chromosomes 2 and Z.
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Affiliation(s)
- C L L Valentim
- Departamento de Ciências Biológicas e Núcleo de Pesquisas em Ciências Biológicas (NUPEB) Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil
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Barthélémy RM, Casanova JP, Faure E. Transcriptome Analysis of ESTs from a Chaetognath Reveals a Deep-Branching Clade of Retrovirus-Like Retrotransposons. Open Virol J 2008; 2:44-60. [PMID: 19440464 PMCID: PMC2678813 DOI: 10.2174/1874357900802010044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 04/08/2008] [Accepted: 04/09/2008] [Indexed: 01/04/2023] Open
Abstract
Chaetognaths constitute a small marine phylum exhibiting several characteristic which are highly unusual in animal genomes, including two classes of both rRNA and protein ribosomal genes. As in this phylum presence of retrovirus-like elements has never been documented, analysis of a published expressed sequence tag (EST) collection of the chaetognath Spadella cephaloptera has been made. Twelve sequences representing transcript sections of reverse transcriptase domain of active retrotransposons were isolated from~11,000 ESTs. Five of them are originated from Gypsy retrovirus-like elements, whereas the other are transcripts from a Bel-Pao LTR-retrotransposon, a Penelope-like element and LINE retrotransposons. Moreover, a part of a putative integrase has also been found. Phylogenetic analyses suggest a deep-branching clade of the retrovirus-like elements, which is in agreement with the probably Cambrian origin of the phylum. Moreover, retrotransposons have not been found in telomeric-like transcripts which are probably constituted by both vertebrate and arthropod canonical repeats.
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Affiliation(s)
- Roxane M Barthélémy
- LATP, CNRS-UMR 6632, Evolution biologique et modélisation, case 5, Université de Provence, Place Victor Hugo, 13331 Marseille cedex 3, France
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Abstract
Draft genome sequences for Schistosoma mansoni and Schistosoma japonicum are now available. However, the identity and importance of most schistosome genes have yet to be determined. Recently, progress has been made towards the genetic manipulation and transgenesis of schistosomes. Both loss-of-function and gain-of-function approaches appear to be feasible in schistosomes based on findings described in the past 5 years. This review focuses on reports of schistosome transgenesis, specifically those dealing with the transformation of schistosomes with exogenous mobile genetic elements and/or their endogenous relatives for the genetic manipulation of schistosomes. Transgenesis mediated by mobile genetic elements offers a potentially tractable route to introduce foreign genes to schistosomes, a means to determine the importance of schistosome genes, including those that could be targeted in novel interventions and the potential to undertake large-scale forward genetics by insertional mutagenesis.
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Verjovski-Almeida S, Venancio TM, Oliveira KCP, Almeida GT, DeMarco R. Use of a 44k oligoarray to explore the transcriptome of Schistosoma mansoni adult worms. Exp Parasitol 2007; 117:236-45. [PMID: 17517391 DOI: 10.1016/j.exppara.2007.04.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Revised: 03/28/2007] [Accepted: 04/10/2007] [Indexed: 10/23/2022]
Abstract
Recent advances in the study of Schistosoma mansoni genome and transcriptome have led to a better description of the S. mansoni gene complement. In this work, we report the design and use of a new S. mansoni 60-mer oligonucleotide microarray platform with approximately 44,000 probes, based on all publicly available cDNA sequence data for S. mansoni and Schistosoma japonicum. The large number of probes combined with the extensive sequence annotation available allowed a comprehensive approach, where most of the S. mansoni transcriptome is represented. Hybridization with adult worm RNA pointed to a set of genes transcriptionally active in this stage of the parasite's life cycle. Interestingly, a large proportion (43%) of genes for which transcription was detected in adults is comprised of "no match" genes, i.e. S. mansoni genes with unknown function and no identifiable orthologs in GenBank. Moreover, detection of bi-directional transcription for 7% of the active "no match" genes in adults leads us to hypothesize a widespread production of antisense RNA in S. mansoni, with possible regulatory roles.
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Affiliation(s)
- Sergio Verjovski-Almeida
- Laboratory of Gene Expression in Eukaryotes, Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes, 748, 05508-000 São Paulo, SP, Brazil.
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Wilson RA, Ashton PD, Braschi S, Dillon GP, Berriman M, Ivens A. 'Oming in on schistosomes: prospects and limitations for post-genomics. Trends Parasitol 2006; 23:14-20. [PMID: 17097923 DOI: 10.1016/j.pt.2006.10.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 10/18/2006] [Accepted: 10/24/2006] [Indexed: 11/30/2022]
Abstract
The recent release of version 3 of the Schistosoma mansoni genome assembly has made a wealth of information available to researchers. Here, progress made in schistosome genomics and post-genomics is considered. The current status of knowledge about the genome, transcriptome, proteome, glycome and immunome is summarized and recent publications briefly reviewed. The prospects for advances in understanding schistosome biology are highlighted. Most importantly, the limitations (which are mostly technical) that need to be addressed before the full potential of the genome database(s) can be realized are emphasized.
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Affiliation(s)
- R Alan Wilson
- Department of Biology, University of York, PO Box 373, York YO10 5YW, UK.
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SmTRC1, a novel Schistosoma mansoni DNA transposon, discloses new families of animal and fungi transposons belonging to the CACTA superfamily. BMC Evol Biol 2006; 6:89. [PMID: 17090310 PMCID: PMC1636069 DOI: 10.1186/1471-2148-6-89] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Accepted: 11/07/2006] [Indexed: 11/13/2022] Open
Abstract
Background The CACTA (also called En/Spm) superfamily of DNA-only transposons contain the core sequence CACTA in their Terminal Inverted Repeats (TIRs) and so far have only been described in plants. Large transcriptome and genome sequence data have recently become publicly available for Schistosoma mansoni, a digenetic blood fluke that is a major causative agent of schistosomiasis in humans, and have provided a comprehensive repository for the discovery of novel genes and repetitive elements. Despite the extensive description of retroelements in S. mansoni, just a single DNA-only transposon belonging to the Merlin family has so far been reported in this organism. Results We describe a novel S. mansoni transposon named SmTRC1, for S. mansoni Transposon Related to CACTA 1, an element that shares several characteristics with plant CACTA transposons. Southern blotting indicates approximately 30–300 copies of SmTRC1 in the S. mansoni genome. Using genomic PCR followed by cloning and sequencing, we amplified and characterized a full-length and a truncated copy of this element. RT-PCR using S. mansoni mRNA followed by cloning and sequencing revealed several alternatively spliced transcripts of this transposon, resulting in distinct ORFs coding for different proteins. Interestingly, a survey of complete genomes from animals and fungi revealed several other novel TRC elements, indicating new families of DNA transposons belonging to the CACTA superfamily that have not previously been reported in these kingdoms. The first three bases in the S. mansoni TIR are CCC and they are identical to those in the TIRs of the insects Aedes aegypti and Tribolium castaneum, suggesting that animal TRCs may display a CCC core sequence. Conclusion The DNA-only transposable element SmTRC1 from S. mansoni exhibits various characteristics, such as generation of multiple alternatively-spliced transcripts, the presence of terminal inverted repeats at the extremities of the elements flanked by direct repeats and the presence of a Transposase_21 domain, that suggest a distant relationship to CACTA transposons from Magnoliophyta. Several sequences from other Metazoa and Fungi code for proteins similar to those encoded by SmTRC1, suggesting that such elements have a common ancestry, and indicating inheritance through vertical transmission before separation of the Eumetazoa, Fungi and Plants.
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Larrondo LF, Canessa P, Vicuña R, Stewart P, Vanden Wymelenberg A, Cullen D. Structure and transcriptional impact of divergent repetitive elements inserted within Phanerochaete chrysosporium strain RP-78 genes. Mol Genet Genomics 2006; 277:43-55. [PMID: 17033809 DOI: 10.1007/s00438-006-0167-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Accepted: 09/06/2006] [Indexed: 12/01/2022]
Abstract
We describe the structure, organization, and transcriptional impact of repetitive elements within the lignin-degrading basidiomycete, Phanerochaete chrysosporium. Searches of the P. chrysosporium genome revealed five copies of pce1, a ~1,750-nt non-autonomous, class II element. Alleles encoding a putative glucosyltransferase and a cytochrome P450 harbor pce insertions and produce incomplete transcripts. Class I elements included pcret1, an intact 8.14-kb gypsy-like retrotransposon inserted within a member of the multicopper oxidase gene family. Additionally, we describe a complex insertion of nested transposons within another putative cytochrome P450 gene. The disrupted allele lies within a cluster of >14 genes, all of which encode family 64 cytochrome P450s. Components of the insertion include a disjoint copia-like element, pcret3, the pol domain of a second retroelement, pcret2, and a duplication of an extended ORF of unknown function. As in the case of the pce elements, pcret1 and pcret2/3 insertions are confined to single alleles, transcripts of which are truncated. The corresponding wild-type alleles are apparently unaffected. In aggregate, P. chrysosporium harbors a complex array of repetitive elements, at least five of which directly influence expression of genes within families of structurally related sequences.
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Affiliation(s)
- Luis F Larrondo
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile and Instituto Milenio de Biología Fundamental y Aplicada, Santiago, Chile
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Copeland CS, Lewis FA, Brindley PJ. Identification of the Boudicca and Sinbad retrotransposons in the genome of the human blood fluke Schistosoma haematobium. Mem Inst Oswaldo Cruz 2006; 101:565-71. [PMID: 17072464 DOI: 10.1590/s0074-02762006000500015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Accepted: 06/08/2006] [Indexed: 11/22/2022] Open
Abstract
Schistosomes have a comparatively large genome, estimated for Schistosoma mansoni to be about 270 megabase pairs (haploid genome). Recent findings have shown that mobile genetic elements constitute significant proportions of the genomes of S. mansoni and S. japonicum. Much less information is available on the genome of the third major human schistosome, S. haematobium. In order to investigate the possible evolutionary origins of the S. mansoni long terminal repeat retrotransposons Boudicca and Sinbad, several genomes were searched by Southern blot for the presence of these retrotransposons. These included three species of schistosomes, S. mansoni, S. japonicum, and S. haematobium, and three related platyhelminth genomes, the liver flukes Fasciola hepatica and Fascioloides magna and the planarian, Dugesia dorotocephala. In addition, Homo sapiens and three snail host genomes, Biomphalaria glabrata, Oncomelania hupensis, and Bulinus truncatus, were examined for possible indications of a horizontal origin for these retrotransposons. Southern hybridization analysis indicated that both Boudicca and Sinbad were present in the genome of S. haematobium. Furthermore, low stringency Southern hybridization analyses suggested that a Boudicca-like retrotransposon was present in the genome of B. truncatus, the snail host of S. haematobium.
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Affiliation(s)
- Claudia S Copeland
- United States Department of Agriculture, Associated Research Service, Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, FL, USA.
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Hypsa V. Parasite histories and novel phylogenetic tools: Alternative approaches to inferring parasite evolution from molecular markers. Int J Parasitol 2006; 36:141-55. [PMID: 16387305 DOI: 10.1016/j.ijpara.2005.10.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2005] [Revised: 10/19/2005] [Accepted: 10/28/2005] [Indexed: 10/25/2022]
Abstract
Parasitological research is often contingent on the knowledge of the phylogeny/genealogy of the studied group. Although molecular phylogenetics has proved to be a powerful tool in such investigations, its application in the traditional fashion, based on a tree inference from the primary nucleotide sequences may, in many cases, be insufficient or even improper. These limitations are due to a number of factors, such as a scarcity/ambiguity of phylogenetic information in the sequences, an intricacy of gene relationships at low phylogenetic levels, or a lack of criteria when deciding among several competing coevolutionary scenarios. With respect to the importance of a precise and reliable phylogenetic background in many biological studies, attempts are being made to extend molecular phylogenetics with a variety of new data sources and methodologies. In this review, selected approaches potentially applicable to parasitological research are presented and their advantages as well as drawbacks are discussed. These issues include the usage of idiosyncratic markers (unique features with presumably low probability of homoplasy), such as insertion of mobile elements, gene rearrangements and secondary structure features; the problem of ancestral polymorphism and reticulate relationships at low phylogenetic levels; and the utility of a molecular clock to facilitate discrimination among alternative scenarios in host-parasite coevolution.
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Affiliation(s)
- Václav Hypsa
- Faculty of Biological Sciences, University of South Bohemia, and Institute of Parasitology, Academy of Sciences of the Czech Republic, Branisovská 31, 37005 Ceské Budejovice, Czech Republic.
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Abstract
The present review considered: (a) the factors that conditioned the early transition from non-life to life; (b) genome structure and complexity in prokaryotes, eukaryotes, and organelles; (c) comparative human chromosome genomics; and (d) the Brazilian contribution to some of these studies. Understanding the dialectical conflict between freedom and organization is fundamental to give meaning to the patterns and processes of organic evolution.
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Affiliation(s)
- Francisco M Salzano
- Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Caixa Postal 15053, 91501-970 Porto Alegre, RS, Brazil.
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Laha T, Kewgrai N, Loukas A, Brindley PJ. Characterization of SR3 reveals abundance of non-LTR retrotransposons of the RTE clade in the genome of the human blood fluke, Schistosoma mansoni. BMC Genomics 2005; 6:154. [PMID: 16271150 PMCID: PMC1291365 DOI: 10.1186/1471-2164-6-154] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Accepted: 11/04/2005] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND It is becoming apparent that perhaps as much as half of the genome of the human blood fluke Schistosoma mansoni is constituted of mobile genetic element-related sequences. Non-long terminal repeat (LTR) retrotransposons, related to the LINE elements of mammals, comprise much of this repetitive component of the schistosome genome. Of more than 12 recognized clades of non-LTR retrotransposons, only members of the CR1, RTE, and R2 clades have been reported from the schistosome genome. RESULTS Inspection of the nucleotide sequence of bacterial artificial chromosome number 49_J_14 from chromosome 1 of the genome of Schistosoma mansoni (GenBank AC093105) revealed the likely presence of several RTE-like retrotransposons. Among these, a new non-LTR retrotransposon designated SR3 was identified and is characterized here. Analysis of gene structure and phylogenetic analysis of both the reverse transcriptase and endonuclease domains of the mobile element indicated that SR3 represented a new family of RTE-like non-LTR retrotransposons. Remarkably, two full-length copies of SR3-like elements were present in BAC 49-J-14, and one of 3,211 bp in length appeared to be intact, indicating SR3 to be an active non-LTR retrotransposon. Both were flanked by target site duplications of 10-12 bp. Southern hybridization and bioinformatics analyses indicated the presence of numerous copies (probably >1,000) of SR3 interspersed throughout the genome of S. mansoni. Bioinformatics analyses also revealed SR3 to be transcribed in both larval and adult developmental stages of S. mansoni and to be also present in the genomes of the other major schistosome parasites of humans, Schistosoma haematobium and S. japonicum. CONCLUSION Numerous copies of SR3, a novel non-LTR retrotransposon of the RTE clade are present in the genome of S. mansoni. Non-LTR retrotransposons of the RTE clade including SR3 appear to have been remarkably successful in colonizing, and proliferation within the schistosome genome.
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Affiliation(s)
- Thewarach Laha
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Nonglack Kewgrai
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Alex Loukas
- Division of Infectious Diseases & Immunology, Queensland Institute of Medical Research, Brisbane, Queensland, 4029, Australia
| | - Paul J Brindley
- Department of Tropical Medicine, and Center for Infectious Diseases, Tulane University, Health Sciences Center, New Orleans, Louisiana, 70112, USA
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Inal JM. Complement C2 receptor inhibitor trispanning: from man to schistosome. ACTA ACUST UNITED AC 2005; 27:320-31. [PMID: 16235057 DOI: 10.1007/s00281-005-0009-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2005] [Accepted: 05/20/2005] [Indexed: 01/03/2023]
Abstract
Horizontal gene transfer (HGT), in relation to genetic transfer between hosts and parasites, is a little described mechanism. Since the complement inhibitor CRIT was first discovered in the human Schistosoma parasite (the causative agent of Bilharzia) and in Trypanosoma cruzi (a parasite causing Chagas' disease), it has been found to be distributed amongst various species, ranging from the early teleost cod to rats and humans. In terms of evolutionary distance, as measured in a phylogenetic analysis of these CRIT genes at nucleotide level, the parasitic species are as removed from their human host as is the rat sequence, suggesting HGT. The hypotheses that CRIT in humans and schistosomes is orthologous and that the presence of CRIT in schistosomes occurs as a result of host-to-parasite HGT are presented in the light of empirical data and the growing body of data on mobile genetic elements in human and schistosome genomes. In summary, these data indicate phylogenetic proximity between Schistosoma and human CRIT, identity of function, high nucleotide/amino acid identity and secondary protein structure, as well as identical genomic organization.
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Affiliation(s)
- Jameel M Inal
- Immunonephrology, Department of Research, University Hospital Basel, Basel, Switzerland.
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Pierce RJ, Wu W, Hirai H, Ivens A, Murphy LD, Noël C, Johnston DA, Artiguenave F, Adams M, Cornette J, Viscogliosi E, Capron M, Balavoine G. Evidence for a Dispersed Hox Gene Cluster in the Platyhelminth Parasite Schistosoma mansoni. Mol Biol Evol 2005; 22:2491-503. [PMID: 16120809 DOI: 10.1093/molbev/msi239] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In most bilaterian organisms so far studied, Hox genes are organized in genomic clusters and determine development along the anteroposterior axis. It has been suggested that this clustering, together with spatial and temporal colinearity of gene expression, represents the ancestral condition. However, in organisms with derived modes of embryogenesis and lineage-dependent mechanisms for the determination of cell fate, temporal colinearity of expression can be lost and Hox cluster organization disrupted, as is the case for the ecdysozoans Drosophila melanogaster and Caenorhabditis elegans and the urochordates Ciona intestinalis and Oikopleura dioica. We sought to determine whether a lophotrochozoan, the platyhelminth parasite Schistosoma mansoni, possesses a conserved or disrupted Hox cluster. Using a polymerase chain reaction (PCR)-based strategy, we have cloned and characterized three novel S. mansoni genes encoding orthologues of Drosophila labial (SmHox1), deformed (SmHox4), and abdominal A (SmHox8), as well as the full-length coding sequence of the previously described Smox1, which we identify as an orthologue of fushi tarazu. Quantitative reverse transcriptase-PCR showed that the four genes were expressed at all life-cycle stages but that levels of expression were differentially regulated. Phylogenetic analysis and the conservation of "parapeptide" sequences C-terminal to the homeodomains of SmHox8 and Smox1 support the grouping of platyhelminths within the lophotrochozoan clade. However, Bacterial Artificial Chromosome (BAC) library screening followed by genome walking failed to reconstitute a cluster. The BAC clones containing Hox genes were sequenced, and in no case were other Hox genes found on the same clone. Moreover, the SmHox4 and SmHox8 genes contained single very large introns (>40 kbp) further indicating that the schistosome Hox cluster is highly extended. Localization of the Hox genes to chromosomes using fluorescence in situ hybridization showed that SmHox4 and SmHox8 are on the long arm of chromosome 4, whereas SmHox1 and Smox1 are on chromosome 3. In silico screening of the available genome sequences corroborated results of Southern blotting and BAC library screening that indicate that there are no paralogues of SmHox1, SmHox4, or SmHox8. The schistosome Hox cluster is therefore not duplicated, but is both dispersed and disintegrated in the genome.
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DeMarco R, Machado AA, Bisson-Filho AW, Verjovski-Almeida S. Identification of 18 new transcribed retrotransposons in Schistosoma mansoni. Biochem Biophys Res Commun 2005; 333:230-40. [PMID: 15939396 DOI: 10.1016/j.bbrc.2005.05.080] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2005] [Accepted: 05/13/2005] [Indexed: 11/28/2022]
Abstract
This work describes 18 new transcribed retrotransposons of the blood fluke Schistosoma mansoni. Among them, 9 were LTR, 8 non-LTR, and 1 Penelope-like element (PLE) retrotransposon. Sequences were generated by in silico reconstruction using S. mansoni ESTs and transcripts obtained by rapid amplification of cDNA ends, complemented in some cases by sequencing of genomic clones amplified by PCR. A novel element from the ancient R2/R4/CRE transposon group is described for the first time in S. mansoni. In addition, one non-LTR retrotransposon family displays long (40-450 bp) 3'-UTR with at least six different transcribed sequences among the copies, five LTR retrotransposons have abundantly transcribed incomplete copies lacking the sequence segment coding for the reverse transcriptase domain, and four non-LTR retrotransposons code for DNA-binding PHD domains that may give them a differential targeting. These results allow for a comprehensive description of the transcribed retrotransposon diversity of this complex human parasite.
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Affiliation(s)
- Ricardo DeMarco
- Departamento de Bioquimica, Instituto de Quimica, Universidade de São Paulo, Brazil
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The Sinbad retrotransposon from the genome of the human blood fluke, Schistosoma mansoni, and the distribution of related Pao-like elements. BMC Evol Biol 2005; 5:20. [PMID: 15725362 PMCID: PMC554778 DOI: 10.1186/1471-2148-5-20] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2004] [Accepted: 02/23/2005] [Indexed: 11/17/2022] Open
Abstract
Background Of the major families of long terminal repeat (LTR) retrotransposons, the Pao/BEL family is probably the least well studied. It is becoming apparent that numerous LTR retrotransposons and other mobile genetic elements have colonized the genome of the human blood fluke, Schistosoma mansoni. Results A proviral form of Sinbad, a new LTR retrotransposon, was identified in the genome of S. mansoni. Phylogenetic analysis indicated that Sinbad belongs to one of five discreet subfamilies of Pao/BEL like elements. BLAST searches of whole genomes and EST databases indicated that members of this clade occurred in species of the Insecta, Nematoda, Echinodermata and Chordata, as well as Platyhelminthes, but were absent from all plants, fungi and lower eukaryotes examined. Among the deuterostomes examined, only aquatic species harbored these types of elements. All four species of nematode examined were positive for Sinbad sequences, although among insect and vertebrate genomes, some were positive and some negative. The full length, consensus Sinbad retrotransposon was 6,287 bp long and was flanked at its 5'- and 3'-ends by identical LTRs of 386 bp. Sinbad displayed a triple Cys-His RNA binding motif characteristic of Gag of Pao/BEL-like elements, followed by the enzymatic domains of protease, reverse transcriptase (RT), RNAseH, and integrase, in that order. A phylogenetic tree of deduced RT sequences from 26 elements revealed that Sinbad was most closely related to an unnamed element from the zebrafish Danio rerio and to Saci-1, also from S. mansoni. It was also closely related to Pao from Bombyx mori and to Ninja of Drosophila simulans. Sinbad was only distantly related to the other schistosome LTR retrotransposons Boudicca, Gulliver, Saci-2, Saci-3, and Fugitive, which are gypsy-like. Southern hybridization and bioinformatics analyses indicated that there were about 50 copies of Sinbad in the S. mansoni genome. The presence of ESTs representing transcripts of Sinbad in numerous developmental stages of S. mansoni along with the identical 5'- and 3'-LTR sequences suggests that Sinbad is an active retrotransposon. Conclusion Sinbad is a Pao/BEL type retrotransposon from the genome of S. mansoni. The Pao/BEL group appears to be comprised of at least five discrete subfamilies, which tend to cluster with host species phylogeny. Pao/BEL type elements appear to have colonized only the genomes of the Animalia. The distribution of these elements in the Ecdysozoa, Deuterostomia, and Lophotrochozoa is discontinuous, suggesting horizontal transmission and/or efficient elimination of Pao-like mobile genetic elements from some genomes.
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Semyenova SK, Chrisanfova GG, Filippova EK, Beer SA, Voronin MV, Ryskov AP. Individual and population variation in cercariae of bird schistosomes of the Trichobilharzia ocellata species group as revealed with the polymerase chain reaction. RUSS J GENET+ 2005. [DOI: 10.1007/s11177-005-0053-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Individual and population variation in cercariae of bird schistosomes of the Trichobilharzia ocellata species group as revealed with the polymerase chain reaction. RUSS J GENET+ 2005. [DOI: 10.1007/pl00022104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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