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Yokomori R, Kusakabe TG, Nakai K. Characterization of trans-spliced chimeric RNAs: insights into the mechanism of trans-splicing. NAR Genom Bioinform 2024; 6:lqae067. [PMID: 38846348 PMCID: PMC11155486 DOI: 10.1093/nargab/lqae067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 05/13/2024] [Accepted: 05/23/2024] [Indexed: 06/09/2024] Open
Abstract
Trans-splicing is a post-transcriptional processing event that joins exons from separate RNAs to produce a chimeric RNA. However, the detailed mechanism of trans-splicing remains poorly understood. Here, we characterize trans-spliced genes and provide insights into the mechanism of trans-splicing in the tunicate Ciona. Tunicates are the closest invertebrates to humans, and their genes frequently undergo trans-splicing. Our analysis revealed that, in genes that give rise to both trans-spliced and non-trans-spliced messenger RNAs, trans-splice acceptor sites were preferentially located at the first functional acceptor site, and their paired donor sites were weak in both Ciona and humans. Additionally, we found that Ciona trans-spliced genes had GU- and AU-rich 5' transcribed regions. Our data and findings not only are useful for Ciona research community, but may also aid in a better understanding of the trans-splicing mechanism, potentially advancing the development of gene therapy based on trans-splicing.
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Affiliation(s)
- Rui Yokomori
- Human Genome Center, Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Takehiro G Kusakabe
- Institute for Integrative Neurobiology, Graduate School of Natural Science, Konan University, Kobe 658-8501, Japan
- Department of Biology, Faculty of Science and Engineering, Konan University, Kobe 658-8501, Japan
| | - Kenta Nakai
- Human Genome Center, Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
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2
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Wei J, Zhang W, Jiang A, Peng H, Zhang Q, Li Y, Bi J, Wang L, Liu P, Wang J, Ge Y, Zhang L, Yu H, Li L, Wang S, Leng L, Chen K, Dong B. Temporospatial hierarchy and allele-specific expression of zygotic genome activation revealed by distant interspecific urochordate hybrids. Nat Commun 2024; 15:2395. [PMID: 38493164 PMCID: PMC10944513 DOI: 10.1038/s41467-024-46780-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/06/2024] [Indexed: 03/18/2024] Open
Abstract
Zygotic genome activation (ZGA) is a universal process in early embryogenesis of metazoan, when the quiescent zygotic nucleus initiates global transcription. However, the mechanisms related to massive genome activation and allele-specific expression (ASE) remain not well understood. Here, we develop hybrids from two deeply diverged (120 Mya) ascidian species to symmetrically document the dynamics of ZGA. We identify two coordinated ZGA waves represent early developmental and housekeeping gene reactivation, respectively. Single-cell RNA sequencing reveals that the major expression wave exhibits spatial heterogeneity and significantly correlates with cell fate. Moreover, allele-specific expression occurs in a species- rather than parent-related manner, demonstrating the divergence of cis-regulatory elements between the two species. These findings provide insights into ZGA in chordates.
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Affiliation(s)
- Jiankai Wei
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266237, China
- MoE Key Laboratory of Evolution and Marine Biodiversity, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003, China
| | - Wei Zhang
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - An Jiang
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Hongzhe Peng
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Quanyong Zhang
- State Key Laboratory of Primate Biomedical Research and Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Yuting Li
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Jianqing Bi
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Linting Wang
- National Center of Mathematics and Interdisciplinary Sciences, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, 100190, China
| | - Penghui Liu
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Jing Wang
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Yonghang Ge
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Liya Zhang
- State Key Laboratory of Primate Biomedical Research and Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China
| | - Haiyan Yu
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Lei Li
- National Center of Mathematics and Interdisciplinary Sciences, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, 100190, China
| | - Shi Wang
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266237, China
| | - Liang Leng
- Institute of Herbgenomics, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China.
| | - Kai Chen
- State Key Laboratory of Primate Biomedical Research and Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, Yunnan, 650500, China.
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119 Haibin Rd, Nansha Dist., Guangzhou, 511458, China.
| | - Bo Dong
- Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China.
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266237, China.
- MoE Key Laboratory of Evolution and Marine Biodiversity, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003, China.
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3
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Song B, Li H, Jiang M, Gao Z, Wang S, Gao L, Chen Y, Li W. slORFfinder: a tool to detect open reading frames resulting from trans-splicing of spliced leader sequences. Brief Bioinform 2023; 24:6972299. [PMID: 36611257 PMCID: PMC9851317 DOI: 10.1093/bib/bbac610] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/16/2022] [Accepted: 12/11/2022] [Indexed: 01/09/2023] Open
Abstract
Trans-splicing of a spliced leader (SL) to the 5' ends of mRNAs is used to produce mature mRNAs in several phyla of great importance to human health and the marine ecosystem. One of the consequences of the addition of SL sequences is the change or disruption of the open reading frames (ORFs) in the recipient transcripts. Given that most SL sequences have one or more of the trinucleotide NUG, including AUG in flatworms, trans-splicing of SL sequences can potentially supply a start codon to create new ORFs, which we refer to as slORFs, in the recipient mRNAs. Due to the lack of a tool to precisely detect them, slORFs were usually neglected in previous studies. In this work, we present the tool slORFfinder, which automatically links the SL sequences to the recipient mRNAs at the trans-splicing sites identified from SL-containing reads of RNA-Seq and predicts slORFs according to the distribution of ribosome-protected footprints (RPFs) on the trans-spliced transcripts. By applying this tool to the analyses of nematodes, ascidians and euglena, whose RPFs are publicly available, we find wide existence of slORFs in these taxa. Furthermore, we find that slORFs are generally translated at higher levels than the annotated ORFs in the genomes, suggesting they might have important functions. Overall, this study provides a tool, slORFfinder (https://github.com/songbo446/slORFfinder), to identify slORFs, which can enhance our understanding of ORFs in taxa with SL machinery.
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Affiliation(s)
| | | | - Mengyun Jiang
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China
| | - Zhongtian Gao
- Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China
| | - Suikang Wang
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China
| | - Lei Gao
- Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China
| | - Yunsheng Chen
- Corresponding authors: Yunsheng Chen, Department of Laboratory Medicine, Shenzhen Children's Hospital, Shenzhen 518038, China, E-mail: ; Wujiao Li, Department of Laboratory Medicine, Shenzhen Childrens' Hospital, Shenzhen 518038, China, E-mail:
| | - Wujiao Li
- Corresponding authors: Yunsheng Chen, Department of Laboratory Medicine, Shenzhen Children's Hospital, Shenzhen 518038, China, E-mail: ; Wujiao Li, Department of Laboratory Medicine, Shenzhen Childrens' Hospital, Shenzhen 518038, China, E-mail:
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4
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Alacid E, Irwin NAT, Smilansky V, Milner DS, Kilias ES, Leonard G, Richards TA. A diversified and segregated mRNA spliced-leader system in the parasitic Perkinsozoa. Open Biol 2022; 12:220126. [PMID: 36000319 PMCID: PMC9399869 DOI: 10.1098/rsob.220126] [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] [Indexed: 11/16/2022] Open
Abstract
Spliced-leader trans-splicing (SLTS) has been described in distantly related eukaryotes and acts to mark mRNAs with a short 5′ exon, giving different mRNAs identical 5′ sequence-signatures. The function of these systems is obscure. Perkinsozoa encompasses a diversity of parasitic protists that infect bivalves, toxic-tide dinoflagellates, fish and frog tadpoles. Here, we report considerable sequence variation in the SLTS-system across the Perkinsozoa and find that multiple variant SLTS-systems are encoded in parallel in the ecologically important Perkinsozoa parasite Parvilucifera sinerae. These results demonstrate that the transcriptome of P. sinerae is segregated based on the addition of different spliced-leader (SL) exons. This segregation marks different gene categories, suggesting that SL-segregation relates to functional differentiation of the transcriptome. By contrast, both sets of gene categories are present in the single SL-transcript type sampled from Maranthos, implying that the SL-segregation of the Parvilucifera transcriptome is a recent evolutionary innovation. Furthermore, we show that the SLTS-system marks a subsection of the transcriptome with increased mRNA abundance and includes genes that encode the spliceosome system necessary for SLTS-function. Collectively, these data provide a picture of how the SLTS-systems can vary within a major evolutionary group and identify how additional transcriptional-complexity can be achieved through SL-segregation.
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Affiliation(s)
- Elisabet Alacid
- Department of Zoology, University of Oxford, Oxford, Oxfordshire OX1 3SZ, UK
| | - Nicholas A T Irwin
- Department of Zoology, University of Oxford, Oxford, Oxfordshire OX1 3SZ, UK.,Merton College, University of Oxford, Oxford, Oxfordshire OX1 4JD, UK
| | - Vanessa Smilansky
- Living Systems Institute, University of Exeter, Exeter, Devon EX4 4QD, UK
| | - David S Milner
- Department of Zoology, University of Oxford, Oxford, Oxfordshire OX1 3SZ, UK
| | - Estelle S Kilias
- Department of Zoology, University of Oxford, Oxford, Oxfordshire OX1 3SZ, UK
| | - Guy Leonard
- Department of Zoology, University of Oxford, Oxford, Oxfordshire OX1 3SZ, UK
| | - Thomas A Richards
- Department of Zoology, University of Oxford, Oxford, Oxfordshire OX1 3SZ, UK
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5
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Chen Z, Huang X, Fu R, Zhan A. Neighbours matter: Effects of genomic organization on gene expression plasticity in response to environmental stresses during biological invasions. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2022; 42:100992. [PMID: 35504120 DOI: 10.1016/j.cbd.2022.100992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 04/07/2022] [Accepted: 04/21/2022] [Indexed: 06/14/2023]
Abstract
Gene expression regulation has been widely recognized as an important molecular mechanism underlying phenotypic plasticity in environmental adaptation. However, it remains largely unexplored on the effects of genomic organization on gene expression plasticity under environmental stresses during biological invasions. Here, we use an invasive model ascidian, Ciona robusta, to investigate how genomic organization affects gene expression in response to salinity stresses during range expansions. Our study showed that neighboring genes were co-expressed and approximately 30% of stress responsive genes were physically clustered on chromosomes. Such coordinated expression was substantially affected by the physical distance and orientation of genes. Interestingly, the overall expression correlation of neighboring genes was significantly decreased under high salinity stresses, illustrating that the co-expression regulation could be disrupted by salinity challenges. Furthermore, the clustering of genes was associated with their function constraints and expression patterns - operon genes enriched in gene expression machinery had the highest transcriptional activity and expression stability. Notably, our analyses showed that the tail-to-tail genes, mainly involved in biological functions related to phosphorylation, homeostatic process, and ion transport, exhibited higher intrinsic expression variability and greater response to salinity challenges. Altogether, the results obtained here provide new insights into the effects of gene organization on gene expression plasticity under environmental challenges, hence improving our knowledge on mechanisms of rapid environmental adaptation during biological invasions.
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Affiliation(s)
- Zaohuang Chen
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, China; University of Chinese Academy of Sciences, Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Xuena Huang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, China
| | - Ruiying Fu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, China; University of Chinese Academy of Sciences, Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Aibin Zhan
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, China; University of Chinese Academy of Sciences, Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, Beijing 100049, China.
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6
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Satou Y, Tokuoka M, Oda-Ishii I, Tokuhiro S, Ishida T, Liu B, Iwamura Y. A Manually Curated Gene Model Set for an Ascidian, Ciona robusta (Ciona intestinalis Type A). Zoolog Sci 2022; 39:253-260. [DOI: 10.2108/zs210102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 01/15/2022] [Indexed: 11/17/2022]
Affiliation(s)
- Yutaka Satou
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Miki Tokuoka
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Izumi Oda-Ishii
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Sinichi Tokuhiro
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Tasuku Ishida
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Boqi Liu
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Yuri Iwamura
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
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7
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Ustyantsev KV, Berezikov EV. Computational analysis of spliced leader trans-splicing in the regenerative flatworm Macrostomum lignano reveals its prevalence in conserved and stem cell related genes. Vavilovskii Zhurnal Genet Selektsii 2021; 25:101-107. [PMID: 34901707 PMCID: PMC8629364 DOI: 10.18699/vj21.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 12/03/2020] [Accepted: 12/08/2020] [Indexed: 11/28/2022] Open
Abstract
In eukaryotes, trans-splicing is a process of nuclear pre-mRNA maturation where two different RNA molecules are joined together by the spliceosomal machinery utilizing mechanisms similar to cis-splicing. In diverse taxa of
lower eukaryotes, spliced leader (SL) trans-splicing is the most frequent type of trans-splicing, when the same sequence
derived from short small nuclear RNA molecules, called SL RNAs, is attached to the 5’ ends of different non-processed
pre-mRNAs. One of the functions of SL trans-splicing is processing polycistronic pre-mRNA molecules transcribed from
operons, when several genes are transcribed as one pre-mRNA molecule. However, only a fraction of trans-spliced
genes reside in operons, suggesting that SL trans-splicing must also have some other, less understood functions. Regenerative flatworms are informative model organisms which hold the keys to understand the mechanism of stem
cell regulation and specialization during regeneration and homeostasis. Their ability to regenerate is fueled by the
division and differentiation of the adult somatic stem cell population called neoblasts. Macrostomum lignano is a flatworm model organism where substantial technological advances have been achieved in recent years, including the
development of transgenesis. Although a large fraction of genes in M. lignano were estimated to be SL trans-spliced,
SL trans-splicing was not studied in detail in M. lignano before. Here, we performed the first comprehensive study of
SL trans-splicing in M. lignano. By reanalyzing the existing genome and transcriptome data of M. lignano, we estimate
that 30 % of its genes are SL trans-spliced, 15 % are organized in operons, and almost 40 % are both SL trans-spliced
and in operons. We annotated and characterized the sequence of SL RNA and characterized conserved cis- and SL transsplicing motifs. Finally, we found that a majority of SL trans-spliced genes are evolutionarily conserved and significantly
over-represented in neoblast-specific genes. Our findings suggest an important role of SL trans-splicing in the regulation and maintenance of neoblasts in M. lignano.
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Affiliation(s)
- K V Ustyantsev
- Institute of Cytology and Genetics of Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - E V Berezikov
- Institute of Cytology and Genetics of Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
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Wenzel MA, Müller B, Pettitt J. SLIDR and SLOPPR: flexible identification of spliced leader trans-splicing and prediction of eukaryotic operons from RNA-Seq data. BMC Bioinformatics 2021; 22:140. [PMID: 33752599 PMCID: PMC7986045 DOI: 10.1186/s12859-021-04009-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/08/2021] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Spliced leader (SL) trans-splicing replaces the 5' end of pre-mRNAs with the spliced leader, an exon derived from a specialised non-coding RNA originating from elsewhere in the genome. This process is essential for resolving polycistronic pre-mRNAs produced by eukaryotic operons into monocistronic transcripts. SL trans-splicing and operons may have independently evolved multiple times throughout Eukarya, yet our understanding of these phenomena is limited to only a few well-characterised organisms, most notably C. elegans and trypanosomes. The primary barrier to systematic discovery and characterisation of SL trans-splicing and operons is the lack of computational tools for exploiting the surge of transcriptomic and genomic resources for a wide range of eukaryotes. RESULTS Here we present two novel pipelines that automate the discovery of SLs and the prediction of operons in eukaryotic genomes from RNA-Seq data. SLIDR assembles putative SLs from 5' read tails present after read alignment to a reference genome or transcriptome, which are then verified by interrogating corresponding SL RNA genes for sequence motifs expected in bona fide SL RNA molecules. SLOPPR identifies RNA-Seq reads that contain a given 5' SL sequence, quantifies genome-wide SL trans-splicing events and predicts operons via distinct patterns of SL trans-splicing events across adjacent genes. We tested both pipelines with organisms known to carry out SL trans-splicing and organise their genes into operons, and demonstrate that (1) SLIDR correctly detects expected SLs and often discovers novel SL variants; (2) SLOPPR correctly identifies functionally specialised SLs, correctly predicts known operons and detects plausible novel operons. CONCLUSIONS SLIDR and SLOPPR are flexible tools that will accelerate research into the evolutionary dynamics of SL trans-splicing and operons throughout Eukarya and improve gene discovery and annotation for a wide range of eukaryotic genomes. Both pipelines are implemented in Bash and R and are built upon readily available software commonly installed on most bioinformatics servers. Biological insight can be gleaned even from sparse, low-coverage datasets, implying that an untapped wealth of information can be retrieved from existing RNA-Seq datasets as well as from novel full-isoform sequencing protocols as they become more widely available.
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Affiliation(s)
- Marius A Wenzel
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, UK.
| | - Berndt Müller
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Jonathan Pettitt
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, AB25 2ZD, UK
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9
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Calvelo J, Juan H, Musto H, Koziol U, Iriarte A. SLFinder, a pipeline for the novel identification of splice-leader sequences: a good enough solution for a complex problem. BMC Bioinformatics 2020; 21:293. [PMID: 32640978 PMCID: PMC7346339 DOI: 10.1186/s12859-020-03610-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 06/17/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Spliced Leader trans-splicing is an important mechanism for the maturation of mRNAs in several lineages of eukaryotes, including several groups of parasites of great medical and economic importance. Nevertheless, its study across the tree of life is severely hindered by the problem of identifying the SL sequences that are being trans-spliced. RESULTS In this paper we present SLFinder, a four-step pipeline meant to identify de novo candidate SL sequences making very few assumptions regarding the SL sequence properties. The pipeline takes transcriptomic de novo assemblies and a reference genome as input and allows the user intervention on several points to account for unexpected features of the dataset. The strategy and its implementation were tested on real RNAseq data from species with and without SL Trans-Splicing. CONCLUSIONS SLFinder is capable to identify SL candidates with good precision in a reasonable amount of time. It is especially suitable for species with unknown SL sequences, generating candidate sequences for further refining and experimental validation.
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Affiliation(s)
- Javier Calvelo
- Laboratorio de Biología Computacional, Departamento de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
- Unidad de Genómica Evolutiva, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
- Sección Biología Celular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Hernán Juan
- Laboratorio de Biología Computacional, Departamento de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Héctor Musto
- Unidad de Genómica Evolutiva, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Uriel Koziol
- Sección Biología Celular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Andrés Iriarte
- Laboratorio de Biología Computacional, Departamento de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
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10
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Satou Y, Nakamura R, Yu D, Yoshida R, Hamada M, Fujie M, Hisata K, Takeda H, Satoh N. A Nearly Complete Genome of Ciona intestinalis Type A (C. robusta) Reveals the Contribution of Inversion to Chromosomal Evolution in the Genus Ciona. Genome Biol Evol 2020; 11:3144-3157. [PMID: 31621849 PMCID: PMC6836712 DOI: 10.1093/gbe/evz228] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2019] [Indexed: 02/07/2023] Open
Abstract
Since its initial publication in 2002, the genome of Ciona intestinalis type A (Ciona robusta), the first genome sequence of an invertebrate chordate, has provided a valuable resource for a wide range of biological studies, including developmental biology, evolutionary biology, and neuroscience. The genome assembly was updated in 2008, and it included 68% of the sequence information in 14 pairs of chromosomes. However, a more contiguous genome is required for analyses of higher order genomic structure and of chromosomal evolution. Here, we provide a new genome assembly for an inbred line of this animal, constructed with short and long sequencing reads and Hi-C data. In this latest assembly, over 95% of the 123 Mb of sequence data was included in the chromosomes. Short sequencing reads predicted a genome size of 114-120 Mb; therefore, it is likely that the current assembly contains almost the entire genome, although this estimate of genome size was smaller than previous estimates. Remapping of the Hi-C data onto the new assembly revealed a large inversion in the genome of the inbred line. Moreover, a comparison of this genome assembly with that of Ciona savignyi, a different species in the same genus, revealed many chromosomal inversions between these two Ciona species, suggesting that such inversions have occurred frequently and have contributed to chromosomal evolution of Ciona species. Thus, the present assembly greatly improves an essential resource for genome-wide studies of ascidians.
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Affiliation(s)
- Yutaka Satou
- Department of Zoology, Graduate School of Science, Kyoto University, Japan
| | - Ryohei Nakamura
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Japan
| | - Deli Yu
- Department of Zoology, Graduate School of Science, Kyoto University, Japan
| | - Reiko Yoshida
- Department of Zoology, Graduate School of Science, Kyoto University, Japan
| | - Mayuko Hamada
- Ushimado Marine Institute, Faculty of Science, Okayama University, Setouchi, Japan
| | - Manabu Fujie
- DNA Sequencing Section, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Kanako Hisata
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Hiroyuki Takeda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Japan
| | - Noriyuki Satoh
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
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11
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Fugacium Spliced Leader Genes Identified from Stranded RNA-Seq Datasets. Microorganisms 2019; 7:microorganisms7060171. [PMID: 31212635 PMCID: PMC6616646 DOI: 10.3390/microorganisms7060171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 05/27/2019] [Accepted: 06/05/2019] [Indexed: 01/10/2023] Open
Abstract
Trans-splicing mechanisms have been documented in many lineages that are widely distributed phylogenetically, including dinoflagellates. The spliced leader (SL) sequence itself is conserved in dinoflagellates, although its gene sequences and arrangements have diversified within or across different species. In this study, we present 18 Fugacium kawagutii SL genes identified from stranded RNA-seq reads. These genes typically have a single SL but can contain several partial SLs with lengths ranging from 103 to 292 bp. Unexpectedly, we find the SL gene transcripts contain sequences upstream of the canonical SL, suggesting that generation of mature transcripts will require additional modifications following trans-splicing. We have also identified 13 SL-like genes whose expression levels and length are comparable to Dino-SL genes. Lastly, introns in these genes were identified and a new site for Sm-protein binding was proposed. Overall, this study provides a strategy for fast identification of SL genes and identifies new sequences of F. kawagutii SL genes to supplement our understanding of trans-splicing.
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12
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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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13
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Brozovic M, Dantec C, Dardaillon J, Dauga D, Faure E, Gineste M, Louis A, Naville M, Nitta KR, Piette J, Reeves W, Scornavacca C, Simion P, Vincentelli R, Bellec M, Aicha SB, Fagotto M, Guéroult-Bellone M, Haeussler M, Jacox E, Lowe EK, Mendez M, Roberge A, Stolfi A, Yokomori R, Brown C, Cambillau C, Christiaen L, Delsuc F, Douzery E, Dumollard R, Kusakabe T, Nakai K, Nishida H, Satou Y, Swalla B, Veeman M, Volff JN, Lemaire P. ANISEED 2017: extending the integrated ascidian database to the exploration and evolutionary comparison of genome-scale datasets. Nucleic Acids Res 2018; 46:D718-D725. [PMID: 29149270 PMCID: PMC5753386 DOI: 10.1093/nar/gkx1108] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 10/22/2017] [Accepted: 11/09/2017] [Indexed: 12/14/2022] Open
Abstract
ANISEED (www.aniseed.cnrs.fr) is the main model organism database for tunicates, the sister-group of vertebrates. This release gives access to annotated genomes, gene expression patterns, and anatomical descriptions for nine ascidian species. It provides increased integration with external molecular and taxonomy databases, better support for epigenomics datasets, in particular RNA-seq, ChIP-seq and SELEX-seq, and features novel interactive interfaces for existing and novel datatypes. In particular, the cross-species navigation and comparison is enhanced through a novel taxonomy section describing each represented species and through the implementation of interactive phylogenetic gene trees for 60% of tunicate genes. The gene expression section displays the results of RNA-seq experiments for the three major model species of solitary ascidians. Gene expression is controlled by the binding of transcription factors to cis-regulatory sequences. A high-resolution description of the DNA-binding specificity for 131 Ciona robusta (formerly C. intestinalis type A) transcription factors by SELEX-seq is provided and used to map candidate binding sites across the Ciona robusta and Phallusia mammillata genomes. Finally, use of a WashU Epigenome browser enhances genome navigation, while a Genomicus server was set up to explore microsynteny relationships within tunicates and with vertebrates, Amphioxus, echinoderms and hemichordates.
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Affiliation(s)
| | | | | | - Delphine Dauga
- Bioself Communication; 28 rue de la Bibliothèque, F-13001 Marseille, France
| | - Emmanuel Faure
- Institut de Biologie Computationnelle, Université de Montpellier, Montpellier, France
- Team VORTEX, Institut de Recherche en Informatique de Toulouse, Universities Toulouse I and III, CNRS, INPT, ENSEEIHT; 2 rue Camichel, BP 7122, F-31071 Toulouse Cedex 7, France
| | | | - Alexandra Louis
- DYOGEN, IBENS, Département de Biologie, Ecole Normale Supérieure, CNRS, Inserm, PSL Research University, F-75005, Paris, France
| | - Magali Naville
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, CNRS; 46 allée d’Italie, F-69364 Lyon, France
| | - Kazuhiro R Nitta
- IBDM, Aix-Marseille Université, CNRS, Campus de Luminy, Case 907; 163 Avenue de Luminy, F-13288 Marseille Cedex 9, France
| | - Jacques Piette
- CRBM, Université de Montpellier, CNRS, Montpellier, France
| | - Wendy Reeves
- Division of Biology, Kansas State University, Manhattan, Kansas
| | | | - Paul Simion
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Renaud Vincentelli
- AFMB, Aix-Marseille Université, CNRS, Campus de Luminy, Case 932, 163 Avenue de Luminy, F-13288 Marseille Cedex 9, France
| | | | - Sameh Ben Aicha
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS; Quai de la Darse, F-06234 Villefranche-sur-Mer Cedex, France
| | | | | | - Maximilian Haeussler
- Santa Cruz Genomics Institute, MS CBSE, University of California, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Edwin Jacox
- CRBM, Université de Montpellier, CNRS, Montpellier, France
| | - Elijah K Lowe
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI48824, USA
| | - Mickael Mendez
- IBDM, Aix-Marseille Université, CNRS, Campus de Luminy, Case 907; 163 Avenue de Luminy, F-13288 Marseille Cedex 9, France
| | | | - Alberto Stolfi
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Rui Yokomori
- Human Genome Center, the Institute of Medical Science, the University of Tokyo, 4-6-1 Shirokanedai, Minato, Tokyo 108-8639, Japan
| | - C Titus Brown
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI48824, USA
- Population Health and Reproduction, UC Davis, Davis, CA 95616, USA
| | - Christian Cambillau
- AFMB, Aix-Marseille Université, CNRS, Campus de Luminy, Case 932, 163 Avenue de Luminy, F-13288 Marseille Cedex 9, France
| | - Lionel Christiaen
- New York University, Center for Developmental Genetics, Department of Biology, 1009 Silver Center, 100 Washington Square East, New York City, NY10003, USA
| | - Frédéric Delsuc
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Emmanuel Douzery
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Rémi Dumollard
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS; Quai de la Darse, F-06234 Villefranche-sur-Mer Cedex, France
| | - Takehiro Kusakabe
- Department of Biology, Faculty of Science and Engineering, Konan University, Kobe 658-8501, Japan
| | - Kenta Nakai
- Human Genome Center, the Institute of Medical Science, the University of Tokyo, 4-6-1 Shirokanedai, Minato, Tokyo 108-8639, Japan
| | - Hiroki Nishida
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Yutaka Satou
- Department of Zoology, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Billie Swalla
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI48824, USA
- Friday Harbor Laboratories, 620 University Road, Friday Harbor, WA 98250-9299, USA
| | - Michael Veeman
- Division of Biology, Kansas State University, Manhattan, Kansas
| | - Jean-Nicolas Volff
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, CNRS; 46 allée d’Italie, F-69364 Lyon, France
| | - Patrick Lemaire
- CRBM, Université de Montpellier, CNRS, Montpellier, France
- Institut de Biologie Computationnelle, Université de Montpellier, Montpellier, France
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14
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Zeller RW. Electroporation in Ascidians: History, Theory and Protocols. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018. [PMID: 29542079 DOI: 10.1007/978-981-10-7545-2_5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Embryonic development depends on the orchestration of hundreds of regulatory and structural genes to initiate expression at the proper time, in the correct spatial domain(s), and in the amounts required for cells and tissues to become specified, determined, and ultimately to differentiate into a multicellular embryo. One of the key approaches to studying embryonic development is the generation of transgenic animals in which recombinant DNA molecules are transiently or stably introduced into embryos to alter gene expression, to manipulate gene function or to serve as reporters for specific cell types or subcellular compartments. In some model systems, such as the mouse, well-defined approaches for generating transgenic animals have been developed. In other systems, particularly non-model systems, a key challenge is to find a way of introducing molecules or other reagents into cells that produces large numbers of embryos with a minimal effect on normal development. A variety of methods have been developed, including the use of viral vectors, microinjection, and electroporation. Here, I describe how electroporation was adapted to generate transgenic embryos in the ascidian, a nontraditional invertebrate chordate model that is particularly well-suited for studying gene regulatory activity during development. I present a review of the electroporation process, describe how electroporation was first implemented in the ascidian, and provide a series of protocols describing the electroporation process, as implemented in our laboratory.
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Affiliation(s)
- Robert W Zeller
- Center for Applied and Experimental Genomics, Department of Biology, San Diego State University, San Diego, CA, USA.
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15
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Segade F, Cota C, Famiglietti A, Cha A, Davidson B. Fibronectin contributes to notochord intercalation in the invertebrate chordate, Ciona intestinalis. EvoDevo 2016; 7:21. [PMID: 27583126 PMCID: PMC5006582 DOI: 10.1186/s13227-016-0056-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Accepted: 08/13/2016] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Genomic analysis has upended chordate phylogeny, placing the tunicates as the sister group to the vertebrates. This taxonomic rearrangement raises questions about the emergence of a tunicate/vertebrate ancestor. RESULTS Characterization of developmental genes uniquely shared by tunicates and vertebrates is one promising approach for deciphering developmental shifts underlying acquisition of novel, ancestral traits. The matrix glycoprotein Fibronectin (FN) has long been considered a vertebrate-specific gene, playing a major instructive role in vertebrate embryonic development. However, the recent computational prediction of an orthologous "vertebrate-like" Fn gene in the genome of a tunicate, Ciona savignyi, challenges this viewpoint suggesting that Fn may have arisen in the shared tunicate/vertebrate ancestor. Here we verify the presence of a tunicate Fn ortholog. Transgenic reporter analysis was used to characterize a Ciona Fn enhancer driving expression in the notochord. Targeted knockdown in the notochord lineage indicates that FN is required for proper convergent extension. CONCLUSIONS These findings suggest that acquisition of Fn was associated with altered notochord morphogenesis in the vertebrate/tunicate ancestor.
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Affiliation(s)
- Fernando Segade
- Department of Anatomy and Cell Biology, University of Pennsylvania School of Dental Medicine, Philadelphia, PA 19104 USA
| | - Christina Cota
- Department of Biology, Swarthmore College, 500 College Ave., Swarthmore, PA 19081 USA
| | - Amber Famiglietti
- Section on Biological Chemistry, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892 USA
| | - Anna Cha
- Department of Systems Biology, Harvard Medical School, Boston, MA USA
| | - Brad Davidson
- Department of Biology, Swarthmore College, 500 College Ave., Swarthmore, PA 19081 USA
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16
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Lei Q, Li C, Zuo Z, Huang C, Cheng H, Zhou R. Evolutionary Insights into RNA trans-Splicing in Vertebrates. Genome Biol Evol 2016; 8:562-77. [PMID: 26966239 PMCID: PMC4824033 DOI: 10.1093/gbe/evw025] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pre-RNA splicing is an essential step in generating mature mRNA. RNA trans-splicing combines two separate pre-mRNA molecules to form a chimeric non-co-linear RNA, which may exert a function distinct from its original molecules. Trans-spliced RNAs may encode novel proteins or serve as noncoding or regulatory RNAs. These novel RNAs not only increase the complexity of the proteome but also provide new regulatory mechanisms for gene expression. An increasing amount of evidence indicates that trans-splicing occurs frequently in both physiological and pathological processes. In addition, mRNA reprogramming based on trans-splicing has been successfully applied in RNA-based therapies for human genetic diseases. Nevertheless, clarifying the extent and evolution of trans-splicing in vertebrates and developing detection methods for trans-splicing remain challenging. In this review, we summarize previous research, highlight recent advances in trans-splicing, and discuss possible splicing mechanisms and functions from an evolutionary viewpoint.
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Affiliation(s)
- Quan Lei
- Department of Genetics, College of Life Sciences, Wuhan University, P.R. China
| | - Cong Li
- Department of Genetics, College of Life Sciences, Wuhan University, P.R. China
| | - Zhixiang Zuo
- Department of Genetics, College of Life Sciences, Wuhan University, P.R. China
| | - Chunhua Huang
- Department of Cell Biology, College of Life Sciences, Wuhan University, P.R. China
| | - Hanhua Cheng
- Department of Cell Biology, College of Life Sciences, Wuhan University, P.R. China
| | - Rongjia Zhou
- Department of Genetics, College of Life Sciences, Wuhan University, P.R. China
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17
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Yokomori R, Shimai K, Nishitsuji K, Suzuki Y, Kusakabe TG, Nakai K. Genome-wide identification and characterization of transcription start sites and promoters in the tunicate Ciona intestinalis. Genome Res 2015; 26:140-50. [PMID: 26668163 PMCID: PMC4691747 DOI: 10.1101/gr.184648.114] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Accepted: 10/13/2015] [Indexed: 02/05/2023]
Abstract
The tunicate Ciona intestinalis, an invertebrate chordate, has recently emerged as a powerful model organism for gene regulation analysis. However, few studies have been conducted to identify and characterize its transcription start sites (TSSs) and promoters at the genome-wide level. Here, using TSS-seq, we identified TSSs at the genome-wide scale and characterized promoters in C. intestinalis. Specifically, we identified TSS clusters (TSCs), high-density regions of TSS-seq tags, each of which appears to originate from an identical promoter. TSCs were found not only at known TSSs but also in other regions, suggesting the existence of many unknown transcription units in the genome. We also identified candidate promoters of 79 ribosomal protein (RP) genes, each of which had the major TSS in a polypyrimidine tract and showed a sharp TSS distribution like human RP gene promoters. Ciona RP gene promoters, however, did not appear to have typical TATA boxes, unlike human RP gene promoters. In Ciona non-RP promoters, two pyrimidine-purine dinucleotides, CA and TA, were frequently used as TSSs. Despite the absence of CpG islands, Ciona TATA-less promoters showed low expression specificity like CpG-associated human TATA-less promoters. By using TSS-seq, we also predicted trans-spliced gene TSSs and found that their downstream regions had higher G+T content than those of non-trans-spliced gene TSSs. Furthermore, we identified many putative alternative promoters, some of which were regulated in a tissue-specific manner. Our results provide valuable information about TSSs and promoter characteristics in C. intestinalis and will be helpful in future analysis of transcriptional regulation in chordates.
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Affiliation(s)
- Rui Yokomori
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8568, Japan
| | - Kotaro Shimai
- Institute for Integrative Neurobiology, Graduate School of Natural Science, Konan University, Kobe 658-8501, Japan
| | - Koki Nishitsuji
- Graduate School of Life Science, University of Hyogo, Kamigori, Hyogo 678-1297, Japan
| | - Yutaka Suzuki
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8568, Japan
| | - Takehiro G Kusakabe
- Institute for Integrative Neurobiology, Graduate School of Natural Science, Konan University, Kobe 658-8501, Japan; Department of Biology, Faculty of Science and Engineering, Konan University, Kobe 658-8501, Japan
| | - Kenta Nakai
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8568, Japan; Institute for Integrative Neurobiology, Graduate School of Natural Science, Konan University, Kobe 658-8501, Japan; Human Genome Center, Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
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18
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Gasparini F, Skobo T, Benato F, Gioacchini G, Voskoboynik A, Carnevali O, Manni L, Dalla Valle L. Characterization of Ambra1 in asexual cycle of a non-vertebrate chordate, the colonial tunicate Botryllus schlosseri, and phylogenetic analysis of the protein group in Bilateria. Mol Phylogenet Evol 2015; 95:46-57. [PMID: 26611831 DOI: 10.1016/j.ympev.2015.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 11/02/2015] [Accepted: 11/03/2015] [Indexed: 12/19/2022]
Abstract
Ambra1 is a positive regulator of autophagy, a lysosome-mediated degradative process involved both in physiological and pathological conditions. Nowadays, Ambra1 has been characterized only in mammals and zebrafish. Through bioinformatics searches and targeted cloning, we report the identification of the complete Ambra1 transcript in a non-vertebrate chordate, the tunicate Botryllus schlosseri. Tunicata is the sister group of Vertebrata and the only chordate group possessing species that reproduce also by blastogenesis (asexual reproduction). B. schlosseri Ambra1 deduced amino acid sequence is shorter than vertebrate homologues but still contains the typical WD40 domain. qPCR analyses revealed that the level of B. schlosseri Ambra1 transcription is temporally regulated along the colonial blastogenetic cycle. By means of similarity searches we identified Wdr5 and Katnb1 as proteins evolutionarily associated to Ambra1. Phylogenetic analyses on Bilateria indicate that: (i) Wdr5 is the most related to Ambra1, so that they may derive from an ancestral gene, (ii) Ambra1 forms a group of ancient genes evolved before the radiation of the taxon, (iii) these orthologous Ambra1 share the two conserved WD40/YVTN repeat-like-containing domains, and (iv) they are characterized by ancient duplications of WD40 repeats within the N-terminal domain.
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Affiliation(s)
- Fabio Gasparini
- Department of Biology, University of Padova, Via Ugo Bassi 35131 Padova, Italy.
| | - Tatjana Skobo
- Department of Biology, University of Padova, Via Ugo Bassi 35131 Padova, Italy.
| | - Francesca Benato
- Department of Biology, University of Padova, Via Ugo Bassi 35131 Padova, Italy.
| | - Giorgia Gioacchini
- Department of Life Science and Environment, Marche Polytechnic University, Via Brecce Bianche, 60131 Ancona, Italy.
| | - Ayelet Voskoboynik
- Department of Pathology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, 265 Campus Drive, 3rd Floor, CA 94305, Stanford, United States.
| | - Oliana Carnevali
- Department of Life Science and Environment, Marche Polytechnic University, Via Brecce Bianche, 60131 Ancona, Italy.
| | - Lucia Manni
- Department of Biology, University of Padova, Via Ugo Bassi 35131 Padova, Italy.
| | - Luisa Dalla Valle
- Department of Biology, University of Padova, Via Ugo Bassi 35131 Padova, Italy.
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19
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Dillon LAL, Okrah K, Hughitt VK, Suresh R, Li Y, Fernandes MC, Belew AT, Corrada Bravo H, Mosser DM, El-Sayed NM. Transcriptomic profiling of gene expression and RNA processing during Leishmania major differentiation. Nucleic Acids Res 2015; 43:6799-813. [PMID: 26150419 PMCID: PMC4538839 DOI: 10.1093/nar/gkv656] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 06/15/2015] [Indexed: 02/06/2023] Open
Abstract
Protozoan parasites of the genus Leishmania are the etiological agents of leishmaniasis, a group of diseases with a worldwide incidence of 0.9–1.6 million cases per year. We used RNA-seq to conduct a high-resolution transcriptomic analysis of the global changes in gene expression and RNA processing events that occur as L. major transforms from non-infective procyclic promastigotes to infective metacyclic promastigotes. Careful statistical analysis across multiple biological replicates and the removal of batch effects provided a high quality framework for comprehensively analyzing differential gene expression and transcriptome remodeling in this pathogen as it acquires its infectivity. We also identified precise 5′ and 3′ UTR boundaries for a majority of Leishmania genes and detected widespread alternative trans-splicing and polyadenylation. An investigation of possible correlations between stage-specific preferential trans-splicing or polyadenylation sites and differentially expressed genes revealed a lack of systematic association, establishing that differences in expression levels cannot be attributed to stage-regulated alternative RNA processing. Our findings build on and improve existing expression datasets and provide a substantially more detailed view of L. major biology that will inform the field and potentially provide a stronger basis for drug discovery and vaccine development efforts.
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Affiliation(s)
- Laura A L Dillon
- Department of Cell Biology and Molecular Genetics, 3128 Bioscience Research Building, University of Maryland, College Park, MD 20742, USA Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD 20742, USA
| | - Kwame Okrah
- Department of Mathematics, University of Maryland, College Park, MD 20742, USA
| | - V Keith Hughitt
- Department of Cell Biology and Molecular Genetics, 3128 Bioscience Research Building, University of Maryland, College Park, MD 20742, USA Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD 20742, USA
| | - Rahul Suresh
- Department of Cell Biology and Molecular Genetics, 3128 Bioscience Research Building, University of Maryland, College Park, MD 20742, USA
| | - Yuan Li
- Department of Cell Biology and Molecular Genetics, 3128 Bioscience Research Building, University of Maryland, College Park, MD 20742, USA Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD 20742, USA
| | - Maria Cecilia Fernandes
- Department of Cell Biology and Molecular Genetics, 3128 Bioscience Research Building, University of Maryland, College Park, MD 20742, USA Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD 20742, USA
| | - A Trey Belew
- Department of Cell Biology and Molecular Genetics, 3128 Bioscience Research Building, University of Maryland, College Park, MD 20742, USA Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD 20742, USA
| | - Hector Corrada Bravo
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD 20742, USA Department of Computer Science, University of Maryland, College Park, MD 20742, USA
| | - David M Mosser
- Department of Cell Biology and Molecular Genetics, 3128 Bioscience Research Building, University of Maryland, College Park, MD 20742, USA
| | - Najib M El-Sayed
- Department of Cell Biology and Molecular Genetics, 3128 Bioscience Research Building, University of Maryland, College Park, MD 20742, USA Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD 20742, USA
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Danks G, Thompson EM. Trans-splicing in metazoans: A link to translational control? WORM 2015; 4:e1046030. [PMID: 26430567 DOI: 10.1080/21624054.2015.1046030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 04/23/2015] [Indexed: 02/07/2023]
Abstract
The trans-splicing of a spliced-leader RNA to a subset of mRNAs is a phenomenon that occurs in many species, including Caenorhabditis elegans, and yet the driving force for its evolution in disparate groups of animals remains unclear. Polycistronic mRNA resulting from the transcription of operons is resolved via trans-splicing, but operons comprise only a sub-set of trans-spliced genes. Using the marine chordate, Oikopleura dioica, we recently tested the hypothesis that metazoan operons accelerate recovery from growth arrest. We found no supporting evidence for this in O. dioica. Instead we found a striking relationship between trans-splicing and maternal mRNA in O. dioica, C. elegans and the ascidian, Ciona intestinalis. Furthermore, in O. dioica and C. elegans, we found evidence to suggest a role for mTOR signaling in the translational control of growth-related, trans-spliced maternal mRNAs. We propose that this may be a mechanism for adjusting egg number in response to nutrient levels in these species.
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Affiliation(s)
- Gemma Danks
- Sars International Centre for Marine Molecular Biology; University of Bergen ; Bergen, Norway
| | - Eric M Thompson
- Sars International Centre for Marine Molecular Biology; University of Bergen ; Bergen, Norway ; Department of Biology; University of Bergen ; Bergen, Norway
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21
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Maternal and zygotic transcriptomes in the appendicularian, Oikopleura dioica: novel protein-encoding genes, intra-species sequence variations, and trans-spliced RNA leader. Dev Genes Evol 2015; 225:149-59. [PMID: 26032664 DOI: 10.1007/s00427-015-0502-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Accepted: 05/18/2015] [Indexed: 10/23/2022]
Abstract
RNA sequencing analysis was carried out to characterize egg and larval transcriptomes in the appendicularian, Oikopleura dioica, a planktonic chordate, which is characterized by rapid development and short life cycle of 5 days, using a Japanese population of the organism. De novo transcriptome assembly matched with 16,423 proteins corresponding to 95.4% of the protein-encoding genes deposited in the OikoBase, the genome database of the Norwegian population. Nucleotide and amino acid sequence identities between the Japanese and Norwegian O. dioica were estimated to be around 91.0 and 94.8%, respectively. We discovered 175 novel protein-encoding genes: 144 unigenes were common to both the Japanese and Norwegian populations, whereas 31 unigenes were not found in the OikoBase genome reference. Among the total 12,311 unigenes, approximately 63% were detected in egg-stage RNAs, whereas 99% were detected in larval stage RNAs; 3772 genes were up-regulated, and 1336 genes were down-regulated more than four-fold in the larvae. Gene ontology analyses characterized gene activities in these two developmental stages. We found a messenger RNA (mRNA) 5' trans-spliced leader, which was observed in 40.8% of the total unique transcripts. It showed preferential linkage to adenine at the 5' ends of the downstream exons. Trans-splicing was observed more frequently in egg mRNAs compared with larva-specific mRNAs.
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A pipeline for the systematic identification of non-redundant full-ORF cDNAs for polymorphic and evolutionary divergent genomes: Application to the ascidian Ciona intestinalis. Dev Biol 2015; 404:149-63. [PMID: 26025923 PMCID: PMC4528069 DOI: 10.1016/j.ydbio.2015.05.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 12/17/2022]
Abstract
Genome-wide resources, such as collections of cDNA clones encoding for complete proteins (full-ORF clones), are crucial tools for studying the evolution of gene function and genetic interactions. Non-model organisms, in particular marine organisms, provide a rich source of functional diversity. Marine organism genomes are, however, frequently highly polymorphic and encode proteins that diverge significantly from those of well-annotated model genomes. The construction of full-ORF clone collections from non-model organisms is hindered by the difficulty of predicting accurately the N-terminal ends of proteins, and distinguishing recent paralogs from highly polymorphic alleles. We report a computational strategy that overcomes these difficulties, and allows for accurate gene level clustering of transcript data followed by the automated identification of full-ORFs with correct 5'- and 3'-ends. It is robust to polymorphism, includes paralog calling and does not require evolutionary proximity to well annotated model organisms. We developed this pipeline for the ascidian Ciona intestinalis, a highly polymorphic member of the divergent sister group of the vertebrates, emerging as a powerful model organism to study chordate gene function, Gene Regulatory Networks and molecular mechanisms underlying human pathologies. Using this pipeline we have generated the first full-ORF collection for a highly polymorphic marine invertebrate. It contains 19,163 full-ORF cDNA clones covering 60% of Ciona coding genes, and full-ORF orthologs for approximately half of curated human disease-associated genes.
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Danks GB, Raasholm M, Campsteijn C, Long AM, Manak JR, Lenhard B, Thompson EM. Trans-splicing and operons in metazoans: translational control in maternally regulated development and recovery from growth arrest. Mol Biol Evol 2014; 32:585-99. [PMID: 25525214 DOI: 10.1093/molbev/msu336] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Polycistronic mRNAs transcribed from operons are resolved via the trans-splicing of a spliced-leader (SL) RNA. Trans-splicing also occurs at monocistronic transcripts. The phlyogenetically sporadic appearance of trans-splicing and operons has made the driving force(s) for their evolution in metazoans unclear. Previous work has proposed that germline expression drives operon organization in Caenorhabditis elegans, and a recent hypothesis proposes that operons provide an evolutionary advantage via the conservation of transcriptional machinery during recovery from growth arrested states. Using a modified cap analysis of gene expression protocol we mapped sites of SL trans-splicing genome-wide in the marine chordate Oikopleura dioica. Tiled microarrays revealed the expression dynamics of trans-spliced genes across development and during recovery from growth arrest. Operons did not facilitate recovery from growth arrest in O. dioica. Instead, we found that trans-spliced transcripts were predominantly maternal. We then analyzed data from C. elegans and Ciona intestinalis and found that an enrichment of trans-splicing and operon gene expression in maternal mRNA is shared between all three species, suggesting that this may be a driving force for operon evolution in metazoans. Furthermore, we found that the majority of known terminal oligopyrimidine (TOP) mRNAs are trans-spliced in O. dioica and that the SL contains a TOP-like motif. This suggests that the SL in O. dioica confers nutrient-dependent translational control to trans-spliced mRNAs via the TOR-signaling pathway. We hypothesize that SL-trans-splicing provides an evolutionary advantage in species that depend on translational control for regulating early embryogenesis, growth and oocyte production in response to nutrient levels.
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Affiliation(s)
- Gemma B Danks
- Computational Biology Unit, Uni Computing, Uni Research, Bergen, Norway Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Martina Raasholm
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Coen Campsteijn
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway Department of Biochemistry, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | | | - J Robert Manak
- Department of Biology, University of Iowa Carver Center for Genomics, Department of Biology, University of Iowa Department of Pediatrics, Carver College of Medicine, University of Iowa
| | - Boris Lenhard
- Computational Biology Unit, Uni Computing, Uni Research, Bergen, Norway Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway Department of Molecular Sciences Imperial College London and MRC Clinical Sciences Centre, London, United Kingdom
| | - Eric M Thompson
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway Department of Biology, University of Bergen, Bergen, Norway
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Mourão MDM, Bitar M, Lobo FP, Peconick AP, Grynberg P, Prosdocimi F, Waisberg M, Cerqueira GC, Macedo AM, Machado CR, Yoshino T, Franco GR. A directed approach for the identification of transcripts harbouring the spliced leader sequence and the effect of trans-splicing knockdown in Schistosoma mansoni. Mem Inst Oswaldo Cruz 2014; 108:707-17. [PMID: 24037192 PMCID: PMC3970683 DOI: 10.1590/0074-0276108062013006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 06/13/2013] [Indexed: 11/22/2022] Open
Abstract
Schistosomiasis is a major neglected tropical disease caused by trematodes from the genus Schistosoma. Because schistosomes exhibit a complex life cycle and numerous mechanisms for regulating gene expression, it is believed that spliced leader (SL) trans-splicing could play an important role in the biology of these parasites. The purpose of this study was to investigate the function of trans-splicing in Schistosoma mansoni through analysis of genes that may be regulated by this mechanism and via silencing SL-containing transcripts through RNA interference. Here, we report our analysis of SL transcript-enriched cDNA libraries from different S. mansoni life stages. Our results show that the trans-splicing mechanism is apparently not associated with specific genes, subcellular localisations or life stages. In cross-species comparisons, even though the sets of genes that are subject to SL trans-splicing regulation appear to differ between organisms, several commonly shared orthologues were observed. Knockdown of trans-spliced transcripts in sporocysts resulted in a systemic reduction of the expression levels of all tested trans-spliced transcripts; however, the only phenotypic effect observed was diminished larval size. Further studies involving the findings from this work will provide new insights into the role of trans-splicing in the biology of S. mansoni and other organisms. All Expressed Sequence Tags generated in this study were submitted to dbEST as five different libraries. The accessions for each library and for the individual sequences are as follows: (i) adult worms of mixed sexes (LIBEST_027999: JZ139310 - JZ139779), (ii) female adult worms (LIBEST_028000: JZ139780 - JZ140379), (iii) male adult worms (LIBEST_028001: JZ140380 - JZ141002), (iv) eggs (LIBEST_028002: JZ141003 - JZ141497) and (v) schistosomula (LIBEST_028003: JZ141498 - JZ141974).
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Affiliation(s)
- Marina de Moraes Mourão
- Grupo de Genômica e Biologia Computacional, Centro de Pesquisas René Rachou, Fiocruz, Belo HorizonteMG, Brasil
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Holland LZ. Genomics, evolution and development of amphioxus and tunicates: The Goldilocks principle. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2014; 324:342-52. [DOI: 10.1002/jez.b.22569] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 01/29/2014] [Accepted: 02/27/2014] [Indexed: 11/10/2022]
Affiliation(s)
- Linda Z. Holland
- Marine Biology Research Division; Scripps Institution of Oceanography; University of California San Diego; La Jolla California 92093-0202 USA
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Bitar M, Boroni M, Macedo AM, Machado CR, Franco GR. The spliced leader trans-splicing mechanism in different organisms: molecular details and possible biological roles. Front Genet 2013; 4:199. [PMID: 24130571 PMCID: PMC3795323 DOI: 10.3389/fgene.2013.00199] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Accepted: 09/19/2013] [Indexed: 01/28/2023] Open
Abstract
The spliced leader (SL) is a gene that generates a functional ncRNA that is composed of two regions: an intronic region of unknown function (SLi) and an exonic region (SLe), which is transferred to the 5′ end of independent transcripts yielding mature mRNAs, in a process known as spliced leader trans-splicing (SLTS). The best described function for SLTS is to solve polycistronic transcripts into monocistronic units, specifically in Trypanosomatids. In other metazoans, it is speculated that the SLe addition could lead to increased mRNA stability, differential recruitment of the translational machinery, modification of the 5′ region or a combination of these effects. Although important aspects of this mechanism have been revealed, several features remain to be elucidated. We have analyzed 157 SLe sequences from 148 species from seven phyla and found a high degree of conservation among the sequences of species from the same phylum, although no considerable similarity seems to exist between sequences of species from different phyla. When analyzing case studies, we found evidence that a given SLe will always be related to a given set of transcripts in different species from the same phylum, and therefore, different SLe sequences from the same species would regulate different sets of transcripts. In addition, we have observed distinct transcript categories to be preferential targets for the SLe addition in different phyla. This work sheds light into crucial and controversial aspects of the SLTS mechanism. It represents a comprehensive study concerning various species and different characteristics of this important post-transcriptional regulatory mechanism.
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Affiliation(s)
- Mainá Bitar
- Laboratório de Genética Bioquímica, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Belo Horizonte, Brazil
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Nydam ML, Netuschil N, Sanders E, Langenbacher A, Lewis DD, Taketa DA, Marimuthu A, Gracey AY, De Tomaso AW. The candidate histocompatibility locus of a Basal chordate encodes two highly polymorphic proteins. PLoS One 2013; 8:e65980. [PMID: 23826085 PMCID: PMC3691228 DOI: 10.1371/journal.pone.0065980] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 04/29/2013] [Indexed: 01/11/2023] Open
Abstract
The basal chordate Botryllus schlosseri undergoes a natural transplantation reaction governed by a single, highly polymorphic locus called the fuhc. Our initial characterization of this locus suggested it encoded a single gene alternatively spliced into two transcripts: a 555 amino acid–secreted form containing the first half of the gene, and a full-length, 1008 amino acid transmembrane form, with polymorphisms throughout the ectodomain determining outcome. We have now found that the locus encodes two highly polymorphic genes which are separated by a 227 bp intergenic region: first, the secreted form as previously described, and a second gene encoding a 531 amino acid membrane-bound gene containing three extracellular immunoglobulin domains. While northern blotting revealed only these two mRNAs, both PCR and mRNA-seq detect a single capped and polyadenylated transcript that encodes processed forms of both genes linked by the intergenic region, as well as other transcripts in which exons of the two genes are spliced together. These results might suggest that the two genes are expressed as an operon, during which both genes are co-transcribed and then trans-spliced into two separate messages. This type of transcriptional regulation has been described in tunicates previously; however, the membrane-bound gene does not encode a typical Splice Leader (SL) sequence at the 5′ terminus that usually accompanies trans-splicing. Thus, the presence of stable transcripts encoding both genes may suggest a novel mechanism of regulation, or conversely may be rare but stable transcripts in which the two mRNAs are linked due to a small amount of read-through by RNA polymerase. Both genes are highly polymorphic and co-expressed on tissues involved in histocompatibility. In addition, polymorphisms on both genes correlate with outcome, although we have found a case in which it appears that the secreted form may be major allorecognition determinant.
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Affiliation(s)
- Marie L. Nydam
- Department of MCD Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Nikolai Netuschil
- Department of MCD Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Erin Sanders
- Department of MCD Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Adam Langenbacher
- Department of MCD Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Daniel D. Lewis
- Department of MCD Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Daryl A. Taketa
- Department of MCD Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Arumugapradeep Marimuthu
- Department of MCD Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Andrew Y. Gracey
- Department of Marine Environmental Biology, University of Southern California, Los Angeles, California, United States of America
| | - Anthony W. De Tomaso
- Department of MCD Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
- * E-mail:
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28
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The genomes of four tapeworm species reveal adaptations to parasitism. Nature 2013; 496:57-63. [PMID: 23485966 PMCID: PMC3964345 DOI: 10.1038/nature12031] [Citation(s) in RCA: 511] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 02/21/2013] [Indexed: 01/27/2023]
Abstract
Tapeworms cause debilitating neglected diseases that can be deadly and often require surgery due to ineffective drugs. Here we present the first analysis of tapeworm genome sequences using the human-infective species Echinococcus multilocularis, E. granulosus, Taenia solium and the laboratory model Hymenolepis microstoma as examples. The 115-141 megabase genomes offer insights into the evolution of parasitism. Synteny is maintained with distantly related blood flukes but we find extreme losses of genes and pathways ubiquitous in other animals, including 34 homeobox families and several determinants of stem cell fate. Tapeworms have species-specific expansions of non-canonical heat shock proteins and families of known antigens; specialised detoxification pathways, and metabolism finely tuned to rely on nutrients scavenged from their hosts. We identify new potential drug targets, including those on which existing pharmaceuticals may act. The genomes provide a rich resource to underpin the development of urgently needed treatments and control.
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Parkinson J, Wasmuth JD, Salinas G, Bizarro CV, Sanford C, Berriman M, Ferreira HB, Zaha A, Blaxter ML, Maizels RM, Fernández C. A transcriptomic analysis of Echinococcus granulosus larval stages: implications for parasite biology and host adaptation. PLoS Negl Trop Dis 2012; 6:e1897. [PMID: 23209850 PMCID: PMC3510090 DOI: 10.1371/journal.pntd.0001897] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 09/25/2012] [Indexed: 01/14/2023] Open
Abstract
Background The cestode Echinococcus granulosus - the agent of cystic echinococcosis, a zoonosis affecting humans and domestic animals worldwide - is an excellent model for the study of host-parasite cross-talk that interfaces with two mammalian hosts. To develop the molecular analysis of these interactions, we carried out an EST survey of E. granulosus larval stages. We report the salient features of this study with a focus on genes reflecting physiological adaptations of different parasite stages. Methodology/Principal Findings We generated ∼10,000 ESTs from two sets of full-length enriched libraries (derived from oligo-capped and trans-spliced cDNAs) prepared with three parasite materials: hydatid cyst wall, larval worms (protoscoleces), and pepsin/H+-activated protoscoleces. The ESTs were clustered into 2700 distinct gene products. In the context of the biology of E. granulosus, our analyses reveal: (i) a diverse group of abundant long non-protein coding transcripts showing homology to a middle repetitive element (EgBRep) that could either be active molecular species or represent precursors of small RNAs (like piRNAs); (ii) an up-regulation of fermentative pathways in the tissue of the cyst wall; (iii) highly expressed thiol- and selenol-dependent antioxidant enzyme targets of thioredoxin glutathione reductase, the functional hub of redox metabolism in parasitic flatworms; (iv) candidate apomucins for the external layer of the tissue-dwelling hydatid cyst, a mucin-rich structure that is critical for survival in the intermediate host; (v) a set of tetraspanins, a protein family that appears to have expanded in the cestode lineage; and (vi) a set of platyhelminth-specific gene products that may offer targets for novel pan-platyhelminth drug development. Conclusions/Significance This survey has greatly increased the quality and the quantity of the molecular information on E. granulosus and constitutes a valuable resource for gene prediction on the parasite genome and for further genomic and proteomic analyses focused on cestodes and platyhelminths. Cestodes are a neglected group of platyhelminth parasites, despite causing chronic infections to humans and domestic animals worldwide. We used Echinococcus granulosus as a model to study the molecular basis of the host-parasite cross-talk during cestode infections. For this purpose, we carried out a survey of the genes expressed by parasite larval stages interfacing with definitive and intermediate hosts. Sequencing from several high quality cDNA libraries provided numerous insights into the expression of genes involved in important aspects of E. granulosus biology, e.g. its metabolism (energy production and antioxidant defences) and the synthesis of key parasite structures (notably, the one exposed to humans and livestock intermediate hosts). Our results also uncovered the existence of an intriguing set of abundant repeat-associated non-protein coding transcripts that may participate in the regulation of gene expression in all surveyed stages. The dataset now generated constitutes a valuable resource for gene prediction on the parasite genome and for further genomic and proteomic studies focused on cestodes and platyhelminths. In particular, the detailed characterization of a range of newly discovered genes will contribute to a better understanding of the biology of cestode infections and, therefore, to the development of products allowing their efficient control.
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Affiliation(s)
- John Parkinson
- Program in Molecular Structure and Function, Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - James D. Wasmuth
- Program in Molecular Structure and Function, Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Gustavo Salinas
- Cátedra de Inmunología, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Cristiano V. Bizarro
- Laboratório de Biologia Molecular de Cestódeos and Laboratorio de Genômica Estrutural e Funcional, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Chris Sanford
- Program in Molecular Structure and Function, Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Matthew Berriman
- Parasite Genomics, The Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Henrique B. Ferreira
- Laboratório de Biologia Molecular de Cestódeos and Laboratorio de Genômica Estrutural e Funcional, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Arnaldo Zaha
- Laboratório de Biologia Molecular de Cestódeos and Laboratorio de Genômica Estrutural e Funcional, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Mark L. Blaxter
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Rick M. Maizels
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail: (RMM); (CF)
| | - Cecilia Fernández
- Cátedra de Inmunología, Facultad de Química, Universidad de la República, Montevideo, Uruguay
- * E-mail: (RMM); (CF)
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30
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Abstract
The study of cis-regulatory DNAs that control developmental gene expression is integral to the modeling of comprehensive genomic regulatory networks for embryogenesis. Ascidian embryos provide a unique opportunity for the analysis of cis-regulatory DNAs with cellular resolution in the context of a simple but typical chordate body plan. Here, we review landmark studies that have laid the foundations for the study of transcriptional enhancers, among other cis-regulatory DNAs, and their roles in ascidian development. The studies using ascidians of the Ciona genus have capitalized on a unique electroporation technique that permits the simultaneous transfection of hundreds of fertilized eggs, which develop rapidly and express transgenes with little mosaicism. Current studies using the ascidian embryo benefit from extensively annotated genomic resources to characterize transcript models in silico. The search for functional noncoding sequences can be guided by bioinformatic analyses combining evolutionary conservation, gene coexpression, and combinations of overrepresented short-sequence motifs. The power of the transient transfection assays has allowed thorough dissection of numerous cis-regulatory modules, which provided insights into the functional constraints that shape enhancer architecture and diversification. Future studies will benefit from pioneering stable transgenic lines and the analysis of chromatin states. Whole genome expression, functional and DNA binding data are being integrated into comprehensive genomic regulatory network models of early ascidian cell specification with a single-cell resolution that is unique among chordate model systems.
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31
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Abstract
The tunicates, or urochordates, constitute a large group of marine animals whose recent common ancestry with vertebrates is reflected in the tadpole-like larvae of most tunicates. Their diversity and key phylogenetic position are enhanced, from a research viewpoint, by anatomically simple and transparent embryos, compact rapidly evolving genomes, and the availability of powerful experimental and computational tools with which to study these organisms. Tunicates are thus a powerful system for exploring chordate evolution and how extreme variation in genome sequence and gene regulatory network architecture is compatible with the preservation of an ancestral chordate body plan.
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Affiliation(s)
- Patrick Lemaire
- Institut du Biologie de Développement de Marseille Luminy (IBDML, UMR 6216, CNRS, Université de la Méditerranée), Parc Scientifique de Luminy Case 907, F-13288, Marseille Cedex 9, France
- Centre de Recherches en Biochimie Macromoléculaire (CRBM, UMR5237, CNRS, Universités Montpellier 1 and 2), 1919 route de Mende, F-34293, Montpellier Cedex 05, France
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Khare P, Mortimer SI, Cleto CL, Okamura K, Suzuki Y, Kusakabe T, Nakai K, Meedel TH, Hastings KEM. Cross-validated methods for promoter/transcription start site mapping in SL trans-spliced genes, established using the Ciona intestinalis troponin I gene. Nucleic Acids Res 2011; 39:2638-48. [PMID: 21109525 PMCID: PMC3074122 DOI: 10.1093/nar/gkq1151] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2010] [Revised: 10/22/2010] [Accepted: 10/25/2010] [Indexed: 11/12/2022] Open
Abstract
In conventionally-expressed eukaryotic genes, transcription start sites (TSSs) can be identified by mapping the mature mRNA 5'-terminal sequence onto the genome. However, this approach is not applicable to genes that undergo pre-mRNA 5'-leader trans-splicing (SL trans-splicing) because the original 5'-segment of the primary transcript is replaced by the spliced leader sequence during the trans-splicing reaction and is discarded. Thus TSS mapping for trans-spliced genes requires different approaches. We describe two such approaches and show that they generate precisely agreeing results for an SL trans-spliced gene encoding the muscle protein troponin I in the ascidian tunicate chordate Ciona intestinalis. One method is based on experimental deletion of trans-splice acceptor sites and the other is based on high-throughput mRNA 5'-RACE sequence analysis of natural RNA populations in order to detect minor transcripts containing the pre-mRNA's original 5'-end. Both methods identified a single major troponin I TSS located ∼460 nt upstream of the trans-splice acceptor site. Further experimental analysis identified a functionally important TATA element 31 nt upstream of the start site. The two methods employed have complementary strengths and are broadly applicable to mapping promoters/TSSs for trans-spliced genes in tunicates and in trans-splicing organisms from other phyla.
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Affiliation(s)
- Parul Khare
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Sandra I. Mortimer
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Cynthia L. Cleto
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Kohji Okamura
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Yutaka Suzuki
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Takehiro Kusakabe
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Kenta Nakai
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Thomas H. Meedel
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Kenneth E. M. Hastings
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
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Gasparini F, Shimeld SM. Analysis of a botryllid enriched-full-length cDNA library: insight into the evolution of spliced leader trans-splicing in tunicates. Dev Genes Evol 2011; 220:329-36. [PMID: 21331664 DOI: 10.1007/s00427-011-0351-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 01/24/2011] [Indexed: 01/22/2023]
Abstract
In some animals, mRNA may be modified after transcription by the addition of a 5' spliced leader sequence. This is known as spliced leader (SL) trans-splicing, and is of uncertain function and evolutionary origin. Here, we report the identification of SL trans-splicing in the colonial ascidian Botryllus schlosseri. Combining our own expressed sequence tag (EST) data with additional data from GenBank, we identify the dominant spliced leader sequence and show it to be similar to that of other ascidians and to that of Oikopleura dioica, a basally diverging tunicate. Gene Ontology analysis of B. schlosseri ESTs with and without a 5' spliced leader shows that genes encoding ribosomal proteins tend not to be trans-spliced, a character shared with the ascidian Ciona intestinalis. We also examine individual cases of genes that produce mRNAs that are SL trans-spliced in B. schlosseri but not in C. intestinalis. We conclude that SL trans-splicing evolved early in the tunicate lineage and shows stability over considerable evolutionary time. However, SL trans-splicing may be gained or lost in individual genes.
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Affiliation(s)
- Fabio Gasparini
- Dipartimento di Biologia, Università degli Studi di Padova, Italy.
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Abstract
Trans-splicing is the joining together of portions of two separate pre-mRNA molecules. The two distinct categories of spliceosomal trans-splicing are genic trans-splicing, which joins exons of different pre-mRNA transcripts, and spliced leader (SL) trans-splicing, which involves an exon donated from a specialized SL RNA. Both depend primarily on the same signals and components as cis-splicing. Genic trans-splicing events producing protein-coding mRNAs have been described in a variety of organisms, including Caenorhabditis elegans and Drosophila. In mammalian cells, genic trans-splicing can be associated with cancers and translocations. SL trans-splicing has mainly been studied in nematodes and trypanosomes, but there are now numerous and diverse phyla (including primitive chordates) where this type of trans-splicing has been detected. Such diversity raises questions as to the evolutionary origin of the process. Another intriguing question concerns the function of trans-splicing, as operon resolution can only account for a small proportion of the total amount of SL trans-splicing.
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Affiliation(s)
- Erika L Lasda
- University of Colorado Denver, Department of Biochemistry and Molecular Genetics; University of Colorado Boulder, Department of Molecular, Cellular, and Developmental Biology
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Harrison N, Kalbfleisch A, Connolly B, Pettitt J, Müller B. SL2-like spliced leader RNAs in the basal nematode Prionchulus punctatus: New insight into the evolution of nematode SL2 RNAs. RNA (NEW YORK, N.Y.) 2010; 16:1500-7. [PMID: 20566669 PMCID: PMC2905750 DOI: 10.1261/rna.2155010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Spliced-leader (SL) trans-splicing has been found in all molecularly characterized nematode species to date, and it is likely to be a nematode synapomorphy. Most information regarding SL trans-splicing has come from the study of nematodes from a single monophyletic group, the Rhabditida, all of which employ SL RNAs that are identical to, or variants of, the SL1 RNA first characterized in Caenorhabditis elegans. In contrast, the more distantly related Trichinella spiralis, belonging to the subclass Dorylaimia, utilizes a distinct set of SL RNAs that display considerable sequence diversity. To investigate whether this is true of other members of the Dorylaimia, we have characterized SL RNAs from Prionchulus punctatus. Surprisingly, this revealed the presence of a set of SLs that show clear sequence similarity to the SL2 family of spliced leaders, which have previously only been found within the rhabditine group (which includes C. elegans). Expression of one of the P. punctatus SL RNAs in C. elegans reveals that it can compete specifically with the endogenous C. elegans SL2 spliced leaders, being spliced to the pre-mRNAs derived from downstream genes in operons, but does not compete with the SL1 spliced leaders. This discovery raises the possibility that SL2-like spliced leaders were present in the last common ancestor of the nematode phylum.
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Affiliation(s)
- Neale Harrison
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, Scotland, United Kingdom
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