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Wilson K, Manner C, Miranda E, Berrio A, Wray GA, McClay DR. An RNA interference approach for functional studies in the sea urchin and its use in analysis of Nodal signaling gradients. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.20.599930. [PMID: 38979202 PMCID: PMC11230266 DOI: 10.1101/2024.06.20.599930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Dicer substrate interfering RNAs (DsiRNAs) destroy targeted transcripts using the RNA-Induced Silencing Complex (RISC) through a process called RNA interference (RNAi). This process is ubiquitous among eukaryotes. Here we report the utility of DsiRNA in embryos of the sea urchin Lytechinus variagatus (Lv). Specific knockdowns phenocopy known morpholino and inhibitor knockdowns, and DsiRNA offers a useful alternative to morpholinos. Methods for designing and obtaining specific DsiRNAs that lead to destruction of targeted mRNA are described. DsiRNAs directed against pks1, an enzyme necessary for pigment production, show how successful DsiRNA perturbations are monitored by RNA in situ analysis and by qPCR to determine relative destruction of targeted mRNA. DsiRNA-based knockdowns phenocopy morpholino- and drug-based inhibition of nodal and lefty. Other knockdowns demonstrate that the RISC operates early in development as well as on genes that are first transcribed hours after gastrulation is completed. Thus, DsiRNAs effectively mediate destruction of targeted mRNA in the sea urchin embryo. The approach offers significant advantages over other widely used methods in the urchin in terms of cost, and ease of procurement, and offers sizeable experimental advantages in terms of ease of handling, injection, and knockdown validation.
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Remsburg CM, Konrad KD, Song JL. RNA localization to the mitotic spindle is essential for early development and is regulated by kinesin-1 and dynein. J Cell Sci 2023; 136:jcs260528. [PMID: 36751992 PMCID: PMC10038151 DOI: 10.1242/jcs.260528] [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: 08/17/2022] [Accepted: 01/27/2023] [Indexed: 02/09/2023] Open
Abstract
Mitosis is a fundamental and highly regulated process that acts to faithfully segregate chromosomes into two identical daughter cells. Localization of gene transcripts involved in mitosis to the mitotic spindle might be an evolutionarily conserved mechanism to ensure that mitosis occurs in a timely manner. We identified many RNA transcripts that encode proteins involved in mitosis localized at the mitotic spindles in dividing sea urchin embryos and mammalian cells. Disruption of microtubule polymerization, kinesin-1 or dynein results in lack of spindle localization of these transcripts in the sea urchin embryo. Furthermore, results indicate that the cytoplasmic polyadenylation element (CPE) within the 3'UTR of the Aurora B transcript, a recognition sequence for CPEB, is essential for RNA localization to the mitotic spindle in the sea urchin embryo. Blocking this sequence results in arrested development during early cleavage stages, suggesting that RNA localization to the mitotic spindle might be a regulatory mechanism of cell division that is important for early development.
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Affiliation(s)
- Carolyn M. Remsburg
- University of Delaware, Department of Biological Sciences, Newark, DE 19716, USA
| | - Kalin D. Konrad
- University of Delaware, Department of Biological Sciences, Newark, DE 19716, USA
| | - Jia L. Song
- University of Delaware, Department of Biological Sciences, Newark, DE 19716, USA
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Quantitative developmental transcriptomes of the Mediterranean sea urchin Paracentrotus lividus. Mar Genomics 2015; 25:89-94. [PMID: 26671332 DOI: 10.1016/j.margen.2015.11.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 11/26/2015] [Accepted: 11/26/2015] [Indexed: 01/28/2023]
Abstract
Embryonic development progresses through the timely activation of thousands of differentially activated genes. Quantitative developmental transcriptomes provide the means to relate global patterns of differentially expressed genes to the emerging body plans they generate. The sea urchin is one of the classic model systems for embryogenesis and the models of its developmental gene regulatory networks are of the most comprehensive of their kind. Thus, the sea urchin embryo is an excellent system for studies of its global developmental transcriptional profiles. Here we produced quantitative developmental transcriptomes of the sea urchin Paracentrotus lividus (P. lividus) at seven developmental stages from the fertilized egg to prism stage. We generated de-novo reference transcriptome and identified 29,817 genes that are expressed at this time period. We annotated and quantified gene expression at the different developmental stages and confirmed the reliability of the expression profiles by QPCR measurement of a subset of genes. The progression of embryo development is reflected in the observed global expression patterns and in our principle component analysis. Our study illuminates the rich patterns of gene expression that participate in sea urchin embryogenesis and provide an essential resource for further studies of the dynamic expression of P. lividus genes.
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Fu Y, Zhang J, Shi Z, Wang G, Li W, Jia L. A key gene of the small RNA pathway in the flounder, Paralichthys olivaceus: identification and functional characterization of dicer. FISH PHYSIOLOGY AND BIOCHEMISTRY 2015; 41:1221-1231. [PMID: 26045159 DOI: 10.1007/s10695-015-0081-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 05/25/2015] [Indexed: 06/04/2023]
Abstract
Dicer is critical for producing mature microRNAs (miRNAs) from precursor molecules and small interfering RNAs and plays an important role in controlling development and metabolism. In the present study, we cloned the flounder dicer gene, which is 6585 nucleotides (nt), including a 5'-untranslated region (UTR) of 231 nt, a 3'-UTR of 663 nt and an open reading frame of 5691 nt encoding a polypeptide of 1897 amino acids, and analyzed the conservation and expression pattern of dicer. The tissue distribution analysis indicated that dicer is abundantly expressed in the brain, heart, liver, spleen, stomach, kidney, gill, muscle, intestine and gonad of adult fish. Temporal expression analysis indicated that dicer mRNA is highly expressed during the embryonic and early larval stages, and exhibits low expression during the metamorphic stages. Treatment with thyroid hormone (TH) or thiourea indirectly or directly up-regulated dicer mRNA levels at 17 and 23 dph, whereas treatment with TH down-regulated dicer mRNA levels at 36 dph. The dicer-specific siRNA significantly down-regulated dicer mRNA and pol-let-7d levels, while pol-let-7d precursor levels were not differentially changed compared with the control (NC). These results demonstrated that dicer plays a key role in development and metabolism through the production of mature miRNAs, providing basic information for further studies concerning the role of dicer in Paralichthys olivaceus development.
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Affiliation(s)
- Yuanshuai Fu
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, 999, Hu-Cheng-Huan Road, Lingang New City, Shangai, 201306, China
| | - Junling Zhang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, 999, Hu-Cheng-Huan Road, Lingang New City, Shangai, 201306, China
| | - Zhiyi Shi
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, 999, Hu-Cheng-Huan Road, Lingang New City, Shangai, 201306, China.
| | - Guyue Wang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, 999, Hu-Cheng-Huan Road, Lingang New City, Shangai, 201306, China
| | - Wejuan Li
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, 999, Hu-Cheng-Huan Road, Lingang New City, Shangai, 201306, China
| | - Liang Jia
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, 999, Hu-Cheng-Huan Road, Lingang New City, Shangai, 201306, China
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Byrum CA, Smith J, Easterling MR, Bridges MC. Restricted expression of karyopherin alpha mRNA in the sea urchin suggests a role in neurogenesis. Gene Expr Patterns 2014; 16:51-60. [PMID: 25218279 DOI: 10.1016/j.gep.2014.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 06/11/2014] [Accepted: 06/25/2014] [Indexed: 10/24/2022]
Abstract
Karyopherin alpha (KAP-α) proteins are critical for the transport of many molecules into the nucleus. In this study, we identified three members of the KAP-α family in the sea urchin Lytechinus variegatus and described the developmental expression of these proteins. Although many importins are assumed to have ubiquitous expression, we found that all three genes were differentially expressed. Both LvKPNA1/5/6 and LvKPNA3/4 accumulated at high levels during cleavage, exhibiting cyclic expression as cells divided. By the blastula and gastrula stages expression decreased, remaining highest in the vegetal plate and archenteron, and by the prism/pluteus stages expression was restricted to the oral surface and gut. Expression of a third KAP-α gene, LvKPNA2/7, was examined in embryos from the mesenchyme blastula to pluteus stages. LvKPNA2/7 mRNA is present in vegetal cells of the mesenchyme blastula and, during gastrulation, it is localized to the archenteron and appears in additional groups of ectodermal cells. Prism/pluteus stage embryos expressed LvKPNA2/7 in the gut and scattered distribution of transcripts in the ciliary band resembled expression patterns of neural cells. We hypothesize that LvKPNA2/7 maintains pluripotency in the neural precursors prior to activation of neural differentiation and believe that this study is an important first step in an effort to better understand the roles of importins during embryogenesis.
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Affiliation(s)
- Christine A Byrum
- Department of Biology, College of Charleston, Rita Liddy Hollings Science Center, 58 Coming Street, Room 214, Charleston, SC, USA.
| | - Jason Smith
- Department of Biology, College of Charleston, Rita Liddy Hollings Science Center, 58 Coming Street, Room 214, Charleston, SC, USA
| | - Marietta R Easterling
- Department of Biology, College of Charleston, Rita Liddy Hollings Science Center, 58 Coming Street, Room 214, Charleston, SC, USA
| | - M Catherine Bridges
- Department of Biology, College of Charleston, Rita Liddy Hollings Science Center, 58 Coming Street, Room 214, Charleston, SC, USA
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Kimura M, Imamoto N. Biological significance of the importin-β family-dependent nucleocytoplasmic transport pathways. Traffic 2014; 15:727-48. [PMID: 24766099 DOI: 10.1111/tra.12174] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 04/22/2014] [Accepted: 04/22/2014] [Indexed: 12/19/2022]
Abstract
Importin-β family proteins (Imp-βs) are nucleocytoplasmic transport receptors (NTRs) that import and export proteins and RNAs through the nuclear pores. The family consists of 14-20 members depending on the biological species, and each member transports a specific group of cargoes. Thus, the Imp-βs mediate multiple, parallel transport pathways that can be regulated separately. In fact, the spatiotemporally differential expressions and the functional regulations of Imp-βs have been reported. Additionally, the biological significance of each pathway has been characterized by linking the function of a member of Imp-βs to a cellular consequence. Connecting these concepts, the regulation of the transport pathways conceivably induces alterations in the cellular physiological states. However, few studies have linked the regulation of an importin-β family NTR to an induced cellular response and the corresponding cargoes, despite the significance of this linkage in comprehending the biological relevance of the transport pathways. This review of recent reports on the regulation and biological functions of the Imp-βs highlights the significance of the transport pathways in physiological contexts and points out the possibility that the identification of yet unknown specific cargoes will reinforce the importance of transport regulation.
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Affiliation(s)
- Makoto Kimura
- Cellular Dynamics Laboratory, RIKEN, Hirosawa 2-1, Wako, Saitama, 351-0198, Japan
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Yajima M, Gustafson EA, Song JL, Wessel GM. Piwi regulates Vasa accumulation during embryogenesis in the sea urchin. Dev Dyn 2014; 243:451-8. [PMID: 24218044 PMCID: PMC4018429 DOI: 10.1002/dvdy.24096] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 10/29/2013] [Accepted: 11/07/2013] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Piwi proteins are essential for germ line development, stem cell maintenance, and more recently found to function in epigenetic and somatic gene regulation. In the sea urchin Strongylocentrotus purpuratus, two Piwi proteins, Seawi and Piwi-like1, have been identified, yet their functional contributions have not been reported. RESULTS Here we found that Seawi protein was localized uniformly in the early embryo and then became enriched in the primordial germ cells (PGCs) (the small micromere lineage) from blastula stage and thereafter. Morpholino knockdown of Sp-seawi diminished PGC-specific localization of Seawi proteins, and altered expression of other germ line markers such as Vasa and Gustavus, but had no effect on Nanos. Furthermore, Seawi knockdown transiently resulted in Vasa positive cell proliferation in the right coelomic pouch that appear to be derived from the small micromere lineage, yet they quickly disappeared with an indication of apoptosis by larval stage. Severe Seawi knockdown resulted in an increased number of apoptotic cells in the entire gut area. CONCLUSION Piwi proteins appear to regulate PGC proliferation perhaps through control of Vasa accumulation. In this organism, Piwi is likely regulating mRNAs, not just transposons, and is potentially functioning both inside and outside of the germ line during embryogenesis.
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Affiliation(s)
- Mamiko Yajima
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, 185 Meeting Street, BOX-GL173, Providence, RI 02912, USA
| | - Eric A. Gustafson
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, 185 Meeting Street, BOX-GL173, Providence, RI 02912, USA
| | | | - Gary M. Wessel
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, 185 Meeting Street, BOX-GL173, Providence, RI 02912, USA
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Martirosyan A, Olesen MJ, Howard KA. Chitosan-Based Nanoparticles for Mucosal Delivery of RNAi Therapeutics. NONVIRAL VECTORS FOR GENE THERAPY - LIPID- AND POLYMER-BASED GENE TRANSFER 2014; 88:325-52. [DOI: 10.1016/b978-0-12-800148-6.00011-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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OULHEN NATHALIE, WESSEL GARYM. Retention of exogenous mRNAs selectively in the germ cells of the sea urchin requires only a 5'-cap and a 3'-UTR. Mol Reprod Dev 2013; 80:561-9. [PMID: 23686945 PMCID: PMC4379035 DOI: 10.1002/mrd.22193] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 04/30/2013] [Indexed: 12/26/2022]
Abstract
The abundance of an mRNA in a cell depends on its overall rates of synthesis and decay. RNA stability is an important element in the regulation of gene expression, and is achieved by a variety of processes including specific recruitment of nucleases and RNAi-associated mechanisms. These mechanisms are particularly important in stem cells, which, in many cases, have attenuated transcription. Here we report that exogenous mRNA injected into fertilized eggs of the sea urchin is selectively retained in the small micromeres, which contribute to the germ line in this organism, beginning in blastulae, when compared to adjacent somatic cells. We show that modification of this exogenous RNA using cap analogs and poly-adenosine tail deletions do not affect its selective retention in the small micromeres, but removal of the cap or of the 3'-untranslated region eliminates any selective mRNA retention in the presumptive germ line. Our results illuminate a likely ancient mechanism used by stem cells to prolong the lifespan of RNAs-either through RNA protection or by the absence of basic RNA degradation mechanisms, which are employed by most other cells of an organism.
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Affiliation(s)
- NATHALIE OULHEN
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
| | - GARY M. WESSEL
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
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Horn T, Boutros M. Design of RNAi reagents for invertebrate model organisms and human disease vectors. Methods Mol Biol 2013; 942:315-346. [PMID: 23027059 DOI: 10.1007/978-1-62703-119-6_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
RNAi has become a very versatile tool to silence gene expression in a variety of organisms, in particular when classical genetic methods are missing. However, the application of this method in functional studies has raised new challenges in order to design RNAi reagents that minimize false positives and false negatives. Because the performance of reagents cannot be validated on a genome-wide scale, improved computational methods are required that consider experimentally derived quality measures. In this chapter, we describe computational methods for the design of RNAi reagents for invertebrate model organisms and human disease vectors, such as Anopheles. We describe procedures for designing short and long double-stranded RNAs for single genes, and evaluate their predicted specificity and efficiency. Using a bioinformatics pipeline we also describe how to design a genome-wide RNAi library for Anopheles gambiae.
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Affiliation(s)
- Thomas Horn
- Department of Cell and Molecular Biology, Heidelberg University, Heidelberg, Germany
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11
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Curtis HJ, Sibley CR, Wood MJA. Mirtrons, an emerging class of atypical miRNA. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 3:617-32. [PMID: 22733569 DOI: 10.1002/wrna.1122] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Post-transcriptional gene silencing (PTGS) via RNA interference (RNAi) is a vital gene regulatory mechanism for fine-tuning gene expression. RNAi effectors termed microRNAs (miRNAs) are implicated in various aspects of animal development and normal physiological function, while dysregulation has been linked to several pathologies. Several atypical miRNA biogenesis pathways have been identified, yet in most cases the reasons for their emergence remain unclear. One of these atypical pathways is the mirtron pathway, where short introns are excised by splicing to generate intermediates of the RNAi pathway, with no cleavage by the microprocessor. Closely related pathways involving tailed-mirtron and simtron biogenesis have also been described. There is extensive evidence that mirtrons function as miRNAs, and while some are evolutionarily conserved across similar species, others appear to have emerged relatively recently. In addition, through exploitation of the potent and sequence-specific silencing capabilities of RNAi, synthetic mirtrons may have potential for overcoming certain therapeutic challenges.
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Affiliation(s)
- Helen J Curtis
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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12
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Kadri S, Hinman VF, Benos PV. RNA deep sequencing reveals differential microRNA expression during development of sea urchin and sea star. PLoS One 2011; 6:e29217. [PMID: 22216218 PMCID: PMC3247247 DOI: 10.1371/journal.pone.0029217] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 11/22/2011] [Indexed: 11/20/2022] Open
Abstract
microRNAs (miRNAs) are small (20–23 nt), non-coding single stranded RNA molecules that act as post-transcriptional regulators of mRNA gene expression. They have been implicated in regulation of developmental processes in diverse organisms. The echinoderms, Strongylocentrotus purpuratus (sea urchin) and Patiria miniata (sea star) are excellent model organisms for studying development with well-characterized transcriptional networks. However, to date, nothing is known about the role of miRNAs during development in these organisms, except that the genes that are involved in the miRNA biogenesis pathway are expressed during their developmental stages. In this paper, we used Illumina Genome Analyzer (Illumina, Inc.) to sequence small RNA libraries in mixed stage population of embryos from one to three days after fertilization of sea urchin and sea star (total of 22,670,000 reads). Analysis of these data revealed the miRNA populations in these two species. We found that 47 and 38 known miRNAs are expressed in sea urchin and sea star, respectively, during early development (32 in common). We also found 13 potentially novel miRNAs in the sea urchin embryonic library. miRNA expression is generally conserved between the two species during development, but 7 miRNAs are highly expressed in only one species. We expect that our two datasets will be a valuable resource for everyone working in the field of developmental biology and the regulatory networks that affect it. The computational pipeline to analyze Illumina reads is available at http://www.benoslab.pitt.edu/services.html.
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Affiliation(s)
- Sabah Kadri
- Lane Center for Computational Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Veronica F. Hinman
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Panayiotis V. Benos
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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Kitagishi Y, Okumura N, Yoshida H, Tateishi C, Nishimura Y, Matsuda S. Dicer functions in aquatic species. JOURNAL OF AMINO ACIDS 2011; 2011:782187. [PMID: 22312469 PMCID: PMC3268030 DOI: 10.4061/2011/782187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 04/02/2011] [Indexed: 12/04/2022]
Abstract
Dicer is an RNase III enzyme with two catalytic subunits, which catalyzes the cleavage of double-stranded RNA to small interfering RNAs and micro-RNAs, which are mainly involved in invasive nucleic acid defense and endogenous genes regulation. Dicer is abundantly expressed in embryos, indicating the importance of the protein in early embryonic development. In addition, Dicer is thought to be involved in defense mechanism against foreign nucleic acids such as viruses. This paper will mainly focus on the recent progress of Dicer-related research and discuss potential RNA interference pathways in aquatic species.
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Affiliation(s)
- Yasuko Kitagishi
- Department of Environmental Health Science, Nara Women's University, Kita-Uoya Nishimachi, Nara 630-8506, Japan
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Yakovlev KV, Battulin NR, Serov OL, Odintsova NA. Isolation of oogonia from ovaries of the sea urchin Strongylocentrotus nudus. Cell Tissue Res 2010; 342:479-90. [DOI: 10.1007/s00441-010-1074-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Accepted: 10/02/2010] [Indexed: 01/11/2023]
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15
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Okamitsu Y, Yamamoto T, Fujii T, Ochiai H, Sakamoto N. Dicer is required for the normal development of sea urchin, Hemicentrotus pulcherrimus. Zoolog Sci 2010; 27:477-86. [PMID: 20528154 DOI: 10.2108/zsj.27.477] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
MicroRNAs are single-stranded RNA molecules with a length of 19-25 nucleotides, which play roles in various biological phenomena, including development, differentiation, apoptosis, by regulating target gene expression. Although the presence of microRNA molecules in sea urchin and the expression of genes involved in microRNA biogenesis during sea urchin development have been reported recently, the function of microRNA in sea urchin development remains to be elucidated. In this study, to understand the function of microRNA in the early development of sea urchin, we focused on Dicer, an essential enzyme for biosynthesis of mature microRNA. We determined the nucleotide sequence of cDNA for a Dicer homolog in the sea urchin, Hemicentrotus pulcherrimus, HpDcr, and found that functional domains of Dicer proteins are conserved in HpDcr. Analyses of its pattern of expression showed that HpDcr mRNA is expressed in embryos at all developmental stages analyzed, and seems to distribute asymmetrically at the morula and later stages. Knockdown of HpDcr resulted in anomalous morphogenesis, such as impairment of gastrulation and skeletogenesis at the mesenchyme blastula stage and later stages, and alteration of mRNA levels of cell type-specific genes. Thus, HpDcr plays important roles in morphogenesis in sea urchin embryos, suggesting that miRNA could be involved in the early development of sea urchin by regulating target gene expression.
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Affiliation(s)
- Yuka Okamitsu
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
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16
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De Mulder K, Pfister D, Kuales G, Egger B, Salvenmoser W, Willems M, Steger J, Fauster K, Micura R, Borgonie G, Ladurner P. Stem cells are differentially regulated during development, regeneration and homeostasis in flatworms. Dev Biol 2009; 334:198-212. [PMID: 19631639 DOI: 10.1016/j.ydbio.2009.07.019] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2009] [Revised: 07/15/2009] [Accepted: 07/15/2009] [Indexed: 01/18/2023]
Abstract
The flatworm stem cell system is exceptional within the animal kingdom, as totipotent stem cells (neoblasts) are the only dividing cells within the organism. In contrast to most organisms, piwi-like gene expression in flatworms is extended from germ cells to somatic stem cells. We describe the isolation and characterization of the piwi homologue macpiwi in the flatworm Macrostomum lignano. We use in situ hybridization, antibody staining and RNA interference to study macpiwi expression and function in adults, during postembryonic development, regeneration and upon starvation. We found novelties regarding piwi function and observed differences to current piwi functions in flatworms. First, macpiwi was essential for the maintenance of somatic stem cells in adult animals. A knock-down of macpiwi led to a complete elimination of stem cells and death of the animals. Second, the regulation of stem cells was different in adults and regenerates compared to postembryonic development. Third, sexual reproduction of M. lignano allowed to follow germline formation during postembryonic development, regeneration, and starvation. Fourth, piwi expression in hatchlings further supports an embryonic formation of the germline in M. lignano. Our findings address new questions in flatworm stem cell research and provide a basis for comparison with higher organisms.
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Affiliation(s)
- Katrien De Mulder
- University of Innsbruck, Institute of Zoology and CMBI, Technikerstrasse 25, A-6020 Innsbruck, Austria
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