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Girstmair J, Telford MJ. Reinvestigating the early embryogenesis in the flatworm Maritigrella crozieri highlights the unique spiral cleavage program found in polyclad flatworms. EvoDevo 2019; 10:12. [PMID: 31285819 PMCID: PMC6588950 DOI: 10.1186/s13227-019-0126-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 06/08/2019] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Spiral cleavage is a conserved, early developmental mode found in several phyla of Lophotrochozoans resulting in highly diverse adult body plans. While the cleavage pattern has clearly been broadly conserved, it has also undergone many modifications in various taxa. The precise mechanisms of how different adaptations have altered the ancestral spiral cleavage pattern are an important ongoing evolutionary question, and adequately answering this question requires obtaining a broad developmental knowledge of different spirally cleaving taxa. In flatworms (Platyhelminthes), the spiral cleavage program has been lost or severely modified in most taxa. Polyclad flatworms, however, have retained the pattern up to the 32-cell stage. Here we study early embryogenesis of the cotylean polyclad flatworm Maritigrella crozieri to investigate how closely this species follows the canonical spiral cleavage pattern and to discover any potential deviations from it. RESULTS Using live imaging recordings and 3D reconstructions of embryos, we give a detailed picture of the events that occur during spiral cleavage in M. crozieri. We suggest, contrary to previous observations, that the four-cell stage is a product of unequal cleavages. We show that that the formation of third and fourth micromere quartets is accompanied by strong blebbing events; blebbing also accompanies the formation of micromere 4d. We find an important deviation from the canonical pattern of cleavages with clear evidence that micromere 4d follows an atypical cleavage pattern, so far exclusively found in polyclad flatworms. CONCLUSIONS Our findings highlight that early development in M. crozieri deviates in several important aspects from the canonical spiral cleavage pattern. We suggest that some of our observations extend to polyclad flatworms in general as they have been described in both suborders of the Polycladida, the Cotylea and Acotylea.
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Affiliation(s)
- Johannes Girstmair
- Centre for Life’s Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, London, WC1E 6BT UK
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Maximilian J. Telford
- Centre for Life’s Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, London, WC1E 6BT UK
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Henry JQ, Lyons DC, Perry KJ, Osborne C. Establishment and activity of the D quadrant organizer in the marine gastropod Crepidula fornicata. Dev Biol 2017; 431:282-296. [DOI: 10.1016/j.ydbio.2017.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 06/15/2017] [Accepted: 09/02/2017] [Indexed: 10/18/2022]
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Fischer AHL, Mozzherin D, Eren AM, Lans KD, Wilson N, Cosentino C, Smith J. SeaBase: a multispecies transcriptomic resource and platform for gene network inference. Integr Comp Biol 2014; 54:250-63. [PMID: 24907201 DOI: 10.1093/icb/icu065] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Marine and aquatic animals are extraordinarily useful as models for identifying mechanisms of development and evolution, regeneration, resistance to cancer, longevity and symbiosis, among many other areas of research. This is due to the great diversity of these organisms and their wide-ranging capabilities. Genomics tools are essential for taking advantage of these "free lessons" of nature. However, genomics and transcriptomics are challenging in emerging model systems. Here, we present SeaBase, a tool for helping to meet these needs. Specifically, SeaBase provides a platform for sharing and searching transcriptome data. More importantly, SeaBase will support a growing number of tools for inferring gene network mechanisms. The first dataset available on SeaBase is a developmental transcriptomic profile of the sea anemone Nematostella vectensis (Anthozoa, Cnidaria). Additional datasets are currently being prepared and we are aiming to expand SeaBase to include user-supplied data for any number of marine and aquatic organisms, thereby supporting many potentially new models for gene network studies. SeaBase can be accessed online at: http://seabase.core.cli.mbl.edu.
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Affiliation(s)
- Antje H L Fischer
- *Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Systems & Control Engineering, University of Magna Graecia, 88100 Catanzaro, Italy*Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Systems & Control Engineering, University of Magna Graecia, 88100 Catanzaro, Italy
| | - Dmitry Mozzherin
- *Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Systems & Control Engineering, University of Magna Graecia, 88100 Catanzaro, Italy
| | - A Murat Eren
- *Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Systems & Control Engineering, University of Magna Graecia, 88100 Catanzaro, Italy
| | - Kristen D Lans
- *Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Systems & Control Engineering, University of Magna Graecia, 88100 Catanzaro, Italy
| | - Nathan Wilson
- *Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Systems & Control Engineering, University of Magna Graecia, 88100 Catanzaro, Italy
| | - Carlo Cosentino
- *Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Systems & Control Engineering, University of Magna Graecia, 88100 Catanzaro, Italy
| | - Joel Smith
- *Marine Biological Laboratory, Woods Hole, MA 02543, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Systems & Control Engineering, University of Magna Graecia, 88100 Catanzaro, Italy
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Chichinadze K, Lazarashvili A, Tkemaladze J. RNA in centrosomes: structure and possible functions. PROTOPLASMA 2013; 250:397-405. [PMID: 22684578 DOI: 10.1007/s00709-012-0422-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 05/22/2012] [Indexed: 06/01/2023]
Abstract
A novel RNA was detected in the centrosomes of Spisula solidissima mollusk oocytes in 2006. This RNA was named centrosomal RNA (cnRNA); five different cnRNAs were described. During the sequencing of the first transcript, cnRNA 11, it was discovered that the transcript contained a conserved structure--a reverse transcriptase domain. In a 2005 study, we speculated about several possible mechanisms for determining the most important functions of centrosomal structures and referred to one of them as an "RNA-dependent mechanism". The discovery of RNA specific to the centrosome is indirect evidence of the centrosomal hypothesis of cellular aging and differentiation. The presence of a reverse transcriptase domain in this type of RNA, together with its uniqueness and specificity, makes the centrosome a place of information storage and reproduction.
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Affiliation(s)
- Konstantin Chichinadze
- I. Beritashvili Center Experimental Biomedicine, 14 Gotua Street, 0160, Tbilisi, Georgia.
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Abstract
The localization of mRNAs in developing animal cells is essential for establishing cellular polarity and setting up the body plan for subsequent development. Cellular and molecular mechanisms by which maternal mRNAs are localized during oogenesis have been extensively studied in Drosophila and Xenopus. In contrast, evidence for mechanisms used in the localization of mRNAs encoded by developmentally important genes has also been accumulating in several other organisms. This offers the opportunity to unravel the fundamental mechanisms of mRNA localization shared among many species, as well as unique mechanisms specifically acquired or retained by animals based on their developmental needs. In addition to maternal mRNAs, the localization of zygotically expressed mRNAs in the cells of cleaving embryos is also important for early development. In this review, mRNA localization dynamics in the oocytes/eggs of Drosophila and Xenopus are first summarized, and evidence for localized mRNAs in the oocytes/eggs and cleaving embryos of other organisms is then presented.
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Affiliation(s)
- Gaku Kumano
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan.
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Rabinowitz JS, Lambert JD. Spiralian quartet developmental potential is regulated by specific localization elements that mediate asymmetric RNA segregation. Development 2010; 137:4039-49. [PMID: 21041364 DOI: 10.1242/dev.055269] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Spiralian embryos are found in a large group of invertebrate phyla but are largely uncharacterized at a molecular level. These embryos are thought to be particularly reliant on autonomous cues for patterning, and thus represent potentially useful models for understanding asymmetric cell division. The series of asymmetric divisions that produce the micromere quartets are particularly important for patterning because they subdivide the animal-vegetal axis into tiers of cells with different developmental potentials. In the embryo of the snail Ilyanassa, the IoLR5 RNA is specifically segregated to the first quartet cells during the third cleavage. Here, we show that this RNA, and later the protein, are maintained in the 1q(121) cells and their descendents throughout development. Some IoLR5-expressing cells become internalized and join the developing cerebral ganglia. Knockdown of IoLR5 protein results in loss of the larval eyes, which normally develop in association with these ganglia. Segregation of this RNA to the first quartet cells does not occur if centrosomal localization is bypassed. We show that the specific inheritance of the RNA by the first quartet cells is driven by a discrete RNA sequence in the 3' UTR that is necessary and sufficient for localization and segregation, and that localization of another RNA to the first quartet is mediated by a similar element. These results demonstrate that micromere quartet identity, a hallmark of the ancient spiralian developmental program, is controlled in part by specific RNA localization motifs.
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Lambert JD, Chan XY, Spiecker B, Sweet HC. Characterizing the embryonic transcriptome of the snail Ilyanassa. Integr Comp Biol 2010; 50:768-77. [PMID: 21558239 DOI: 10.1093/icb/icq121] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The snail Ilyanassa obsoleta is a useful model for a variety of investigations in the fields of developmental biology, cell biology, larval ecology, ecotoxicology, parasitology, and chemical ecology. To enhance such studies, we have carried out two cDNA sequencing projects to characterize the mRNA transcripts that are present during development of this embryo. These efforts have generated 480 megabases of new sequence, which have been assembled into transcript contigs and represent thousands of newly identified Ilyanassa genes. We identified the orthologs of 182 transcription factors in these data, focusing on families that are likely to be sequence-specific transcriptional regulators. To demonstrate the utility of identifying and examining such transcripts, we describe the expression pattern during organogenesis for IoOnecut, an Ilyanassa ortholog of the HNF6/onecut family of transcription factors.
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Affiliation(s)
- J David Lambert
- Department of Biology, University of Rochester, NY 14627, USA.
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Henry JJ, Perry KJ, Fukui L, Alvi N. Differential localization of mRNAs during early development in the mollusc, Crepidula fornicata. Integr Comp Biol 2010; 50:720-33. [PMID: 21558235 DOI: 10.1093/icb/icq088] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Certain mRNAs have been shown to be segregated in different cells in various metazoan embryos. These events represent aspects of autonomous mechanisms that establish particular embryonic cell fates and axial properties associated with asymmetric cell divisions. The spiralian lophotrochozoans (which include molluscs, annelids, nemerteans, gnathostomulids, dicyemid mesozoans, entoprocts, and platyhelminthes) exhibit a highly conserved pattern of early development that involves stereotypical, asymmetric cell divisions (termed "spiral cleavage"). Recently, it was demonstrated that various mRNAs are dynamically localized to the centrosomes in specific cells during early development in the gastropod mollusc, Ilyanassa obsoleta. During subsequent cell divisions, these messages become segregated in particular daughter cells, and it has been proposed that these events distinguish the developmental potential of these cells within the early embryo of I. obsoleta. The molecular mechanisms underlying these events, however, are still unknown. Here we show for the first time in another spiralian lophotrochozoan (the gastropod Crepidula fornicata) that similar patterns of mRNA localization take place during early development. To characterize the transcriptome of early development, and identify candidate genes for the expression analyses, high-throughput sequencing was carried out, via GS FLX Titanium 454 pyrosequencing. The annotated sequences have been made available as a resource for the scientific community (www.life.illinoi.edu/henry/crepidula_databases.html). Presumably, specific proteins associated with centrosomes may be important for these mRNA localization events. In silico sequence comparisons with known centriolar/centrosomal, ciliary/basal body proteomes shows that a large number of those proteins are represented in the collection of expressed sequence tags of C. fornicata annotated in this study. These data should be useful for future studies of the role of specific mRNAs in controlling cell fate and axial specification in the spiralian Lophotrochozoa, and for dissecting the underlying molecular mechanisms that accomplish these events.
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Affiliation(s)
- Jonathan J Henry
- Department of Cell and Developmental Biology, University of Illinois, 601 S. Goodwin Ave., Urbana IL 61801, USA.
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Henry JJ, Collin R, Perry KJ. The slipper snail, Crepidula: an emerging lophotrochozoan model system. THE BIOLOGICAL BULLETIN 2010; 218:211-229. [PMID: 20570845 DOI: 10.1086/bblv218n3p211] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Recent developmental and genomic research focused on "slipper snails" in the genus Crepidula has positioned Crepidula fornicata as a de facto model system for lophotrochozoan development. Here we review recent developments, as well as earlier reports demonstrating the widespread use of this system in studies of development and life history. Recent studies have resulted in a well-resolved fate map of embryonic cell lineage, documented mechanisms for axis determination and D quadrant specification, preliminary gene expression patterns, and the successful application of loss- and gain-of-function assays. The recent development of expressed sequence tags and preliminary genomics work will promote the use of this system, particularly in the area of developmental biology. A wealth of comparative information on phylogenetic relationships, variation in mode of development within the family, and numerous studies on larval biology and metamorphosis, primarily in Crepidula fornicata, make these snails a powerful tool for studies of the evolution of the mechanisms of development in the Mollusca and Lophotrochozoa. By bringing a review of the current state of knowledge of Crepidula life histories and development together with some detailed experimental methods, we hope to encourage further use of this system in various fields of investigation.
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Affiliation(s)
- Jonathan J Henry
- Department of Cell & Developmental Biology, University of Illinois, 601 S. Goodwin Ave, Urbana, Illinois 61801, USA.
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