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Tjeerdema E, Lee Y, Metry R, Hamdoun A. Semi-automated, high-content imaging of drug transporter knockout sea urchin (Lytechinus pictus) embryos. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2024; 342:313-329. [PMID: 38087422 DOI: 10.1002/jez.b.23231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 11/08/2023] [Accepted: 11/19/2023] [Indexed: 05/01/2024]
Abstract
A defining feature of sea urchins is their extreme fecundity. Urchins produce millions of transparent, synchronously developing embryos, ideal for spatial and temporal analysis of development. This biological feature has been effectively utilized for ensemble measurement of biochemical changes. However, it has been underutilized in imaging studies, where single embryo measurements are used. Here we present an example of how stable genetics and high content imaging, along with machine learning-based image analysis, can be used to exploit the fecundity and synchrony of sea urchins in imaging-based drug screens. Building upon our recently created sea urchin ABCB1 knockout line, we developed a high-throughput assay to probe the role of this drug transporter in embryos. We used high content imaging to compare accumulation and toxicity of canonical substrates and inhibitors of the transporter, including fluorescent molecules and antimitotic cancer drugs, in homozygous knockout and wildtype embryos. To measure responses from the resulting image data, we used a nested convolutional neural network, which rapidly classified embryos according to fluorescence or cell division. This approach identified sea urchin embryos with 99.8% accuracy and determined two-cell and aberrant embryos with 96.3% and 89.1% accuracy, respectively. The results revealed that ABCB1 knockout embryos accumulated the transporter substrate calcein 3.09 times faster than wildtypes. Similarly, knockouts were 4.71 and 3.07 times more sensitive to the mitotic poisons vinblastine and taxol. This study paves the way for large scale pharmacological screens in the sea urchin embryo.
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Affiliation(s)
- Evan Tjeerdema
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
| | - Yoon Lee
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
| | - Rachel Metry
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
| | - Amro Hamdoun
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
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2
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Vasa nucleates asymmetric translation along the mitotic spindle during unequal cell divisions. Nat Commun 2022; 13:2145. [PMID: 35444184 PMCID: PMC9021227 DOI: 10.1038/s41467-022-29855-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 04/04/2022] [Indexed: 11/23/2022] Open
Abstract
mRNA translation on the spindle is hypothesized to be an essential strategy for the localized production of cell regulators. This mechanism may be important particularly in early embryonic cells, which have a large diffusion volume and that undergo rapid cell divisions. Evidence to test such a hypothesis has been, however, limited. Here, we use an embryo with both symmetric and asymmetric cell divisions and manipulate Vasa protein, an RNA-helicase, on the spindle in live sea urchin embryos. We learned that the spindle serves as a major site of translation and that protein synthesis within a single spindle can be unequal and help drive asymmetric cell divisions during embryogenesis. Recruiting Vasa to the ectopic sub-cellular region induced a new site of translation, disturbed asymmetric translation on the spindle, and changed the cell fate. Based on these observations, we conclude that Vasa functions in localized translation, which provides a spatiotemporal control in protein synthesis and is essential for rapidly developing embryonic cells. Association of mRNA translation with the mitotic spindle is thought to be involved in localized production of cell fate determinants. Here, the authors show Vasa facilitates asymmetric translation, which contributes to differential regulation during sea urchin embryogenesis.
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3
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Emura N, Yajima M. Micromere formation and its evolutionary implications in the sea urchin. Curr Top Dev Biol 2022; 146:211-238. [PMID: 35152984 PMCID: PMC8868499 DOI: 10.1016/bs.ctdb.2021.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The micromeres of the sea urchin embryo are distinct from other blastomeres. After they arise through an asymmetric cell division at the 8- to 16-cell stage, micromeres immediately function as organizers. They also commit themselves to specific cell fates such as larval skeletogenic cells and primordial germ cells, while other blastomeres remain plastic and uncommitted at the 16-cell stage. In the phylum Echinodermata, only the sea urchin (class Echinoidea) embryo forms micromeres that serve as apparent organizers during early embryogenesis. Therefore, it is considered that micromeres are the derived features and that modification(s) of the developmental system allowed evolutionary introduction of this unique cell lineage. In this chapter, we summarize the both historic and recent observations that demonstrate unique properties of micromeres and discuss how this lineage of micromeres may have arisen during echinoderm evolution.
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Beatman TR, Buckley KM, Cary GA, Hinman VF, Ettensohn CA. A nomenclature for echinoderm genes. DATABASE-THE JOURNAL OF BIOLOGICAL DATABASES AND CURATION 2021; 2021:6350312. [PMID: 34386815 PMCID: PMC8361234 DOI: 10.1093/database/baab052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/02/2021] [Accepted: 08/02/2021] [Indexed: 12/16/2022]
Abstract
Echinoderm embryos and larvae are prominent experimental model systems for studying developmental mechanisms. High-quality, assembled, annotated genome sequences are now available for several echinoderm species, including representatives from most classes. The increased availability of these data necessitates the development of a nomenclature that assigns universally interpretable gene symbols to echinoderm genes to facilitate cross-species comparisons of gene functions, both within echinoderms and across other phyla. This paper describes the implementation of an improved set of echinoderm gene nomenclature guidelines that both communicates meaningful orthology information in protein-coding gene symbols and names and establishes continuity with nomenclatures developed for major vertebrate model organisms, including humans. Differences between the echinoderm gene nomenclature guidelines and vertebrate guidelines are examined and explained. This nomenclature incorporates novel solutions to allow for several types of orthologous relationships, including the single echinoderm genes with multiple vertebrate co-orthologs that result from whole-genome-duplication events. The current version of the Echinoderm Gene Nomenclature Guidelines can be found at https://www.echinobase.org/gene/static/geneNomenclature.jsp Database URL https://www.echinobase.org/
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Affiliation(s)
- Thomas R Beatman
- Department of Biological Sciences, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA.,Echinobase, #646 Mellon Institute, 4400 Fifth Ave, Pittsburgh, PA 15213, USA
| | - Katherine M Buckley
- Department of Biological Sciences, Auburn University, 101 Rouse Life Sciences, Auburn, AL 36849, USA
| | - Gregory A Cary
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - Veronica F Hinman
- Department of Biological Sciences, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA.,Echinobase, #646 Mellon Institute, 4400 Fifth Ave, Pittsburgh, PA 15213, USA
| | - Charles A Ettensohn
- Department of Biological Sciences, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA.,Echinobase, #646 Mellon Institute, 4400 Fifth Ave, Pittsburgh, PA 15213, USA
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5
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Wolff A, Hinman V. The Use of Larval Sea Stars and Sea Urchins in the Discovery of Shared Mechanisms of Metazoan Whole-Body Regeneration. Genes (Basel) 2021; 12:genes12071063. [PMID: 34356079 PMCID: PMC8303351 DOI: 10.3390/genes12071063] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 07/08/2021] [Accepted: 07/09/2021] [Indexed: 02/07/2023] Open
Abstract
The ability to regenerate is scattered among the metazoan tree of life. Further still, regenerative capacity varies widely within these specific organisms. Numerous organisms, all with different regenerative capabilities, have been studied at length and key similarities and disparities in how regeneration occurs have been identified. In order to get a better grasp on understanding regeneration as a whole, we must search for new models that are capable of extensive regeneration, as well as those that have been under sampled in the literature. As invertebrate deuterostomes, echinoderms fit both of these requirements. Multiple members regenerate various tissue types at all life stages, including examples of whole-body regeneration. Interrogations in two highly studied echinoderms, the sea urchin and the sea star, have provided knowledge of tissue and whole-body regeneration at various life stages. Work has begun to examine regeneration in echinoderm larvae, a potential new system for understanding regenerative mechanisms in a basal deuterostome. Here, we review the ways these two animals’ larvae have been utilized as a model of regeneration.
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Affiliation(s)
- Andrew Wolff
- Department of Biological Sciences, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA;
| | - Veronica Hinman
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
- Correspondence: ; Tel.: +1-412-268-9348
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6
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Carata E, Tenuzzo BA, Mariano S, Setini A, Fidaleo M, Dini L. RETRACTED ARTICLE: Genotoxicity and alteration of the Gene Regulatory Network expression during Paracentrotus lividus development in the presence of carbon nanoparticles. Toxicol Res 2021; 38:257. [PMID: 35415079 PMCID: PMC8960529 DOI: 10.1007/s43188-020-00081-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/13/2020] [Accepted: 12/17/2020] [Indexed: 10/25/2022] Open
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7
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Bardhan A, Deiters A, Ettensohn CA. Conditional gene knockdowns in sea urchins using caged morpholinos. Dev Biol 2021; 475:21-29. [PMID: 33684434 DOI: 10.1016/j.ydbio.2021.02.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/22/2021] [Accepted: 02/28/2021] [Indexed: 12/01/2022]
Abstract
Echinoderms are important experimental models for analyzing embryonic development, but a lack of spatial and temporal control over gene perturbations has hindered developmental studies using these animals. Morpholino antisense oligonucleotides (MOs) have been used successfully by the echinoderm research community for almost two decades, and MOs remain the most widely used tool for acute gene knockdowns in these organisms. Echinoderm embryos develop externally and are optically transparent, making them ideally-suited to many light-based approaches for analyzing and manipulating development. Studies using zebrafish embryos have demonstrated the effectiveness of photoactivatable (caged) MOs for conditional gene knockdowns. Here we show that caged MOs, synthesized using nucleobase-caged monomers, provide light-regulated control over gene expression in sea urchin embryos. Our work provides the first robust approach for conditional gene silencing in this prominent model system.
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Affiliation(s)
- Anirban Bardhan
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Alexander Deiters
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Charles A Ettensohn
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA.
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8
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Kipryushina YO, Yakovlev KV. Maternal control of early patterning in sea urchin embryos. Differentiation 2020; 113:28-37. [PMID: 32371341 DOI: 10.1016/j.diff.2020.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 04/10/2020] [Accepted: 04/17/2020] [Indexed: 02/06/2023]
Abstract
Sea urchin development has been studied extensively for more than a century and considered regulative since the first experimental evidence. Further investigations have repeatedly supported this standpoint by revealing the presence of inductive mechanisms that alter cell fate decisions at early cleavage stages and flexibility of development in response to environmental conditions. Some features indicate that sea urchin development is not completely regulative, but actually includes determinative events. In 16-cell embryos, mesomeres and macromeres represent multipotency, while the cell fate of most vegetal micromeres is restricted. It is known that the mature sea urchin eggs are polarized by the asymmetrical distribution of some maternal mRNAs and proteins. Spatially-distributed maternal factors are necessary for the orientation of the primary animal-vegetal axis, which is established by both maternal and zygotic mechanisms later in development. The secondary dorsal-ventral axis is conditionally specified later in development. Dorsal-ventral polarity is very liable during the early cleavages, though more recent data argue that its direction may be oriented by maternal asymmetry. In this review, we focus on the role of maternal factors in initial embryonic patterning during the first cleavages of sea urchin embryos before activation of the embryonic genome.
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Affiliation(s)
- Yulia O Kipryushina
- Laboratory of Cytotechnology, National Scientific Center of Marine Biology, Far Eastern Branch of the Russian Academy of Sciences, Palchevsky St. 17, 690041, Vladivostok, Russia
| | - Konstantin V Yakovlev
- Laboratory of Cytotechnology, National Scientific Center of Marine Biology, Far Eastern Branch of the Russian Academy of Sciences, Palchevsky St. 17, 690041, Vladivostok, Russia; Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.
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9
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Ettensohn CA. The gene regulatory control of sea urchin gastrulation. Mech Dev 2020; 162:103599. [PMID: 32119908 DOI: 10.1016/j.mod.2020.103599] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 02/21/2020] [Accepted: 02/24/2020] [Indexed: 02/07/2023]
Abstract
The cell behaviors associated with gastrulation in sea urchins have been well described. More recently, considerable progress has been made in elucidating gene regulatory networks (GRNs) that underlie the specification of early embryonic territories in this experimental model. This review integrates information from these two avenues of work. I discuss the principal cell movements that take place during sea urchin gastrulation, with an emphasis on molecular effectors of the movements, and summarize our current understanding of the gene regulatory circuitry upstream of those effectors. A case is made that GRN biology can provide a causal explanation of gastrulation, although additional analysis is needed at several levels of biological organization in order to provide a deeper understanding of this complex morphogenetic process.
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Affiliation(s)
- Charles A Ettensohn
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Ave., Pittsburgh, PA 15213, USA.
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10
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Hogan JD, Keenan JL, Luo L, Ibn-Salem J, Lamba A, Schatzberg D, Piacentino ML, Zuch DT, Core AB, Blumberg C, Timmermann B, Grau JH, Speranza E, Andrade-Navarro MA, Irie N, Poustka AJ, Bradham CA. The developmental transcriptome for Lytechinus variegatus exhibits temporally punctuated gene expression changes. Dev Biol 2019; 460:139-154. [PMID: 31816285 DOI: 10.1016/j.ydbio.2019.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 12/03/2019] [Accepted: 12/04/2019] [Indexed: 10/25/2022]
Abstract
Embryonic development is arguably the most complex process an organism undergoes during its lifetime, and understanding this complexity is best approached with a systems-level perspective. The sea urchin has become a highly valuable model organism for understanding developmental specification, morphogenesis, and evolution. As a non-chordate deuterostome, the sea urchin occupies an important evolutionary niche between protostomes and vertebrates. Lytechinus variegatus (Lv) is an Atlantic species that has been well studied, and which has provided important insights into signal transduction, patterning, and morphogenetic changes during embryonic and larval development. The Pacific species, Strongylocentrotus purpuratus (Sp), is another well-studied sea urchin, particularly for gene regulatory networks (GRNs) and cis-regulatory analyses. A well-annotated genome and transcriptome for Sp are available, but similar resources have not been developed for Lv. Here, we provide an analysis of the Lv transcriptome at 11 timepoints during embryonic and larval development. Temporal analysis suggests that the gene regulatory networks that underlie specification are well-conserved among sea urchin species. We show that the major transitions in variation of embryonic transcription divide the developmental time series into four distinct, temporally sequential phases. Our work shows that sea urchin development occurs via sequential intervals of relatively stable gene expression states that are punctuated by abrupt transitions.
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Affiliation(s)
- John D Hogan
- Program in Bioinformatics, Boston University, Boston, MA, USA
| | | | - Lingqi Luo
- Program in Bioinformatics, Boston University, Boston, MA, USA
| | - Jonas Ibn-Salem
- Evolution and Development Group, Max-Planck Institute for Molecular Genetics, Berlin, Germany; Faculty of Biology, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Arjun Lamba
- Biology Department, Boston University, Boston, MA, USA
| | | | - Michael L Piacentino
- Program in Molecular and Cellular Biology and Biochemistry, Boston University, Boston, MA, USA
| | - Daniel T Zuch
- Program in Molecular and Cellular Biology and Biochemistry, Boston University, Boston, MA, USA
| | - Amanda B Core
- Biology Department, Boston University, Boston, MA, USA
| | | | - Bernd Timmermann
- Sequencing Core Facility, Max-Planck Institute for Molecular Genetics, Berlin, Germany
| | - José Horacio Grau
- Dahlem Centre for Genome Research and Medical Systems Biology, Environmental and Phylogenomics Group, Berlin, Germany; Museum für Naturkunde Berlin, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
| | - Emily Speranza
- Program in Bioinformatics, Boston University, Boston, MA, USA
| | | | - Naoki Irie
- Department of Biological Sciences, University of Tokyo, Tokyo, Japan
| | - Albert J Poustka
- Evolution and Development Group, Max-Planck Institute for Molecular Genetics, Berlin, Germany; Dahlem Centre for Genome Research and Medical Systems Biology, Environmental and Phylogenomics Group, Berlin, Germany
| | - Cynthia A Bradham
- Program in Bioinformatics, Boston University, Boston, MA, USA; Biology Department, Boston University, Boston, MA, USA; Program in Molecular and Cellular Biology and Biochemistry, Boston University, Boston, MA, USA.
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11
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Poon J, Fries A, Wessel GM, Yajima M. Evolutionary modification of AGS protein contributes to formation of micromeres in sea urchins. Nat Commun 2019; 10:3779. [PMID: 31439829 PMCID: PMC6706577 DOI: 10.1038/s41467-019-11560-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 07/18/2019] [Indexed: 02/01/2023] Open
Abstract
Evolution is proposed to result, in part, from acquisition of new developmental programs. One such example is the appearance of the micromeres in a sea urchin that form by an asymmetric cell division at the 4th embryonic cleavage and function as a major signaling center in the embryo. Micromeres are not present in other echinoderms and thus are considered as a derived feature, yet its acquisition mechanism is unknown. Here, we report that the polarity factor AGS and its associated proteins are responsible for micromere formation. Evolutionary modifications of AGS protein seem to have provided the cortical recruitment and binding of AGS to the vegetal cortex, contributing to formation of micromeres in the sea urchins. Indeed, introduction of sea urchin AGS into the sea star embryo induces asymmetric cell divisions, suggesting that the molecular evolution of AGS protein is key in the transition of echinoderms to micromere formation and the current developmental style of sea urchins not seen in other echinoderms.
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Affiliation(s)
- Jessica Poon
- MCB Department, Brown University, 185 Meeting Street, BOXG-L277, Providence, RI, 02912, USA
| | - Annaliese Fries
- MCB Department, Brown University, 185 Meeting Street, BOXG-L277, Providence, RI, 02912, USA
| | - Gary M Wessel
- MCB Department, Brown University, 185 Meeting Street, BOXG-L277, Providence, RI, 02912, USA
| | - Mamiko Yajima
- MCB Department, Brown University, 185 Meeting Street, BOXG-L277, Providence, RI, 02912, USA.
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12
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Yaguchi J, Yamazaki A, Yaguchi S. Meis transcription factor maintains the neurogenic ectoderm and regulates the anterior-posterior patterning in embryos of a sea urchin, Hemicentrotus pulcherrimus. Dev Biol 2018; 444:1-8. [PMID: 30266259 DOI: 10.1016/j.ydbio.2018.09.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 09/07/2018] [Accepted: 09/24/2018] [Indexed: 01/18/2023]
Abstract
Precise body axis formation is an essential step in the development of multicellular organisms, for most of which the molecular gradient and/or specifically biased localization of cell-fate determinants in eggs play important roles. In sea urchins, however, any biased proteins and mRNAs have not yet been identified in the egg except for vegetal cortex molecules, suggesting that sea urchin development is mostly regulated by uniformly distributed maternal molecules with contributions to axis formation that are not well characterized. Here, we describe that the maternal Meis transcription factor regulates anterior-posterior axis formation through maintenance of the most anterior territory in embryos of a sea urchin, Hemicentrotus pulcherrimus. Loss-of-function experiments revealed that Meis is intrinsically required for maintenance of the anterior neuroectoderm specifier foxQ2 after hatching and, consequently, the morphant lost anterior neuroectoderm characteristics. In addition, the expression patterns of univin and VEGF, the lateral ectoderm markers, and the mesenchyme-cell pattern shifted toward the anterior side in Meis morphants more than they did in control embryos, indicating that Meis contributes to the precise anteroposterior patterning by regulating the anterior neuroectodermal fate.
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Affiliation(s)
- Junko Yaguchi
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1, Shimoda, Shizuoka 415-0025, Japan
| | - Atsuko Yamazaki
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1, Shimoda, Shizuoka 415-0025, Japan
| | - Shunsuke Yaguchi
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1, Shimoda, Shizuoka 415-0025, Japan.
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13
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McClay DR, Miranda E, Feinberg SL. Neurogenesis in the sea urchin embryo is initiated uniquely in three domains. Development 2018; 145:dev167742. [PMID: 30413529 PMCID: PMC6240313 DOI: 10.1242/dev.167742] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 09/25/2018] [Indexed: 12/23/2022]
Abstract
Many marine larvae begin feeding within a day of fertilization, thus requiring rapid development of a nervous system to coordinate feeding activities. Here, we examine the patterning and specification of early neurogenesis in sea urchin embryos. Lineage analysis indicates that neurons arise locally in three regions of the embryo. Perturbation analyses showed that when patterning is disrupted, neurogenesis in the three regions is differentially affected, indicating distinct patterning requirements for each neural domain. Six transcription factors that function during proneural specification were identified and studied in detail. Perturbations of these proneural transcription factors showed that specification occurs differently in each neural domain prior to the Delta-Notch restriction signal. Though gene regulatory network state changes beyond the proneural restriction are largely unresolved, the data here show that the three neural regions already differ from each other significantly early in specification. Future studies that define the larval nervous system in the sea urchin must therefore separately characterize the three populations of neurons that enable the larva to feed, to navigate, and to move food particles through the gut.
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Affiliation(s)
- David R McClay
- Department of Biology, 124 Science Drive, Duke University, Durham, NC 27708, USA
| | - Esther Miranda
- Department of Biology, 124 Science Drive, Duke University, Durham, NC 27708, USA
| | - Stacy L Feinberg
- Department of Biology, 124 Science Drive, Duke University, Durham, NC 27708, USA
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14
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Ghafari M, Mashaghi A. On the role of topology in regulating transcriptional cascades. Phys Chem Chem Phys 2017; 19:25168-25179. [DOI: 10.1039/c7cp02671d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Topology of interactions in a transcriptional cascade determines the behavior of its signal-response profile and the activation states of genes.
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Affiliation(s)
- Mahan Ghafari
- Leiden Academic Centre for Drug Research
- Faculty of Mathematics and Natural Sciences
- Leiden University
- Leiden
- The Netherlands
| | - Alireza Mashaghi
- Leiden Academic Centre for Drug Research
- Faculty of Mathematics and Natural Sciences
- Leiden University
- Leiden
- The Netherlands
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15
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Karakostis K, Zanella-Cléon I, Immel F, Guichard N, Dru P, Lepage T, Plasseraud L, Matranga V, Marin F. A minimal molecular toolkit for mineral deposition? Biochemistry and proteomics of the test matrix of adult specimens of the sea urchin Paracentrotus lividus. J Proteomics 2016; 136:133-44. [DOI: 10.1016/j.jprot.2016.01.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 12/22/2015] [Accepted: 01/04/2016] [Indexed: 12/16/2022]
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16
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Cavalieri V, Spinelli G. Ectopic hbox12 Expression Evoked by Histone Deacetylase Inhibition Disrupts Axial Specification of the Sea Urchin Embryo. PLoS One 2015; 10:e0143860. [PMID: 26618749 PMCID: PMC4664418 DOI: 10.1371/journal.pone.0143860] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 11/09/2015] [Indexed: 12/26/2022] Open
Abstract
Dorsal/ventral patterning of the sea urchin embryo depends upon the establishment of a Nodal-expressing ventral organizer. Recently, we showed that spatial positioning of this organizer relies on the dorsal-specific transcription of the Hbox12 repressor. Building on these findings, we determined the influence of the epigenetic milieu on the expression of hbox12 and nodal genes. We find that Trichostatin-A, a potent and selective histone-deacetylases inhibitor, induces histone hyperacetylation in hbox12 chromatin, evoking broad ectopic expression of the gene. Transcription of nodal concomitantly drops, prejudicing dorsal/ventral polarity of the resulting larvae. Remarkably, impairing hbox12 function, either in a spatially-restricted sector or in the whole embryo, specifically rescues nodal transcription in Trichostatin-A-treated larvae. Beyond strengthen the notion that nodal expression is not allowed in the presence of functional Hbox12 in the same cells, these results highlight a critical role of histone deacetylases in regulating the spatial expression of hbox12.
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Affiliation(s)
- Vincenzo Cavalieri
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Italy
- Mediterranean Center for Human Health Advanced Biotechnologies (CHAB), University of Palermo, Italy
- * E-mail: (VC); (GS)
| | - Giovanni Spinelli
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Italy
- * E-mail: (VC); (GS)
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17
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Magesky A, Pelletier É. Toxicity mechanisms of ionic silver and polymer-coated silver nanoparticles with interactions of functionalized carbon nanotubes on early development stages of sea urchin. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2015; 167:106-23. [PMID: 26280079 DOI: 10.1016/j.aquatox.2015.07.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 07/17/2015] [Accepted: 07/20/2015] [Indexed: 05/14/2023]
Abstract
Exposures of aquatic organisms to multiple contaminants are likely to take place in estuarine and coastal areas and combined effects on early life stages have to be examined. Among emerging contaminants, ionic silver (Ag(+)) and silver nanoparticles (AgNps) have demonstrated contrasting effects on marine invertebrates, but their interactions with functionalized carbon nanotubes (f-SWCNTs) have not yet been investigated in details. In order to observe the impacts and understand the toxicity mechanism of Ag(+) and polymer-coated AgNps, and their combined effects with f-SWCNTs, successive development stages of embryos of sea urchin, Strongylocentrotus droebachiensis, were exposed to Ag(+), AgNps and f-SWCNTs, separately and in mixtures using moderate environmental concentrations. We also assessed long-term effects of treatments under recovery conditions. Morphological endpoints such as archenteron elongation, primary and secondary mesenchyme cells fate, pigment cells migration, spiculogenic cells and gut development indicated different effects of silver and nanosilver forms during successive development stages. Whereas Ag(+) induced vegetalization and extrusion of mesenchyme cells on early embryos; f-SWCNTs+Ag(+) strongly interfered with gut regionalization in late larvae. Sensitive blastocoelar cells got vacuolized and shapeless with AgNps, but not with mixtures with f-SWCNTs. Increased concentrations of Ag(+) and f-SWCNTs+Ag(+) led to the most disruptive effects during development, but f-SWCNTs+Ag(+) caused the highest mortality rate during the recovery period, which indicated far-reaching effects driven by f-SWCNTs and their ability to keep silver more available during exposure period.
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Affiliation(s)
- Adriano Magesky
- Institut de Sciences de la mer de Rimouski (ISMER), Université du Québec à Rimouski, 310, allée des Ursulines, Rimouski, QC, Canada G5L 3A1
| | - Émilien Pelletier
- Institut de Sciences de la mer de Rimouski (ISMER), Université du Québec à Rimouski, 310, allée des Ursulines, Rimouski, QC, Canada G5L 3A1.
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18
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Symmetry Breaking and Establishment of Dorsal/Ventral Polarity in the Early Sea Urchin Embryo. Symmetry (Basel) 2015. [DOI: 10.3390/sym7041721] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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19
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Cavalieri V, Spinelli G. Early asymmetric cues triggering the dorsal/ventral gene regulatory network of the sea urchin embryo. eLife 2014; 3:e04664. [PMID: 25457050 PMCID: PMC4273433 DOI: 10.7554/elife.04664] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 12/01/2014] [Indexed: 12/16/2022] Open
Abstract
Dorsal/ventral (DV) patterning of the sea urchin embryo relies on a ventrally-localized organizer expressing Nodal, a pivotal regulator of the DV gene regulatory network. However, the inceptive mechanisms imposing the symmetry-breaking are incompletely understood. In Paracentrotus lividus, the Hbox12 homeodomain-containing repressor is expressed by prospective dorsal cells, spatially facing and preceding the onset of nodal transcription. We report that Hbox12 misexpression provokes DV abnormalities, attenuating nodal and nodal-dependent transcription. Reciprocally, impairing hbox12 function disrupts DV polarity by allowing ectopic expression of nodal. Clonal loss-of-function, inflicted by blastomere transplantation or gene-transfer assays, highlights that DV polarization requires Hbox12 action in dorsal cells. Remarkably, the localized knock-down of nodal restores DV polarity of embryos lacking hbox12 function. Finally, we show that hbox12 is a dorsal-specific negative modulator of the p38-MAPK activity, which is required for nodal expression. Altogether, our results suggest that Hbox12 function is essential for proper positioning of the DV organizer.
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Affiliation(s)
- Vincenzo Cavalieri
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, Palermo, Italy
| | - Giovanni Spinelli
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, Palermo, Italy
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20
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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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21
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Fischer AHL, Pang K, Henry JQ, Martindale MQ. A cleavage clock regulates features of lineage-specific differentiation in the development of a basal branching metazoan, the ctenophore Mnemiopsis leidyi. EvoDevo 2014; 5:4. [PMID: 24485336 PMCID: PMC3909359 DOI: 10.1186/2041-9139-5-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 11/20/2013] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND An important question in experimental embryology is to understand how the developmental potential responsible for the generation of distinct cell types is spatially segregated over developmental time. Classical embryological work showed that ctenophores, a group of gelatinous marine invertebrates that arose early in animal evolution, display a highly stereotyped pattern of early development and a precocious specification of blastomere fates. Here we investigate the role of autonomous cell specification and the developmental timing of two distinct ctenophore cell types (motile compound comb-plate-like cilia and light-emitting photocytes) in embryos of the lobate ctenophore, Mnemiopsis leidyi. RESULTS In Mnemiopsis, 9 h after fertilization, comb plate cilia differentiate into derivatives of the E lineage, while the bioluminescent capability begins in derivatives of the M lineage. Arresting cleavage with cytochalasin B at the 1-, 2- or 4-cell stage does not result in blastomere death; however, no visible differentiation of the comb-plate-like cilia or bioluminescence was observed. Cleavage arrest at the 8- or 16-cell stage, in contrast, results in the expression of both differentiation products. Fate-mapping experiments indicate that only the lineages of cells that normally express these markers in an autonomous fashion during normal development express these traits in cleavage-arrested 8- and 16-cell stage embryos. Lineages that form comb plates in a non-autonomous fashion (derivatives of the M lineage) do not. Timed actinomycin D and puromycin treatments show that transcription and translation are required for comb formation and suggest that the segregated material might be necessary for activation of the appropriate genes. Interestingly, even in the absence of cytokinesis, differentiation markers appear to be activated at the correct times. Treatments with a DNA synthesis inhibitor, aphidicolin, show that the number of nuclear divisions, and perhaps the DNA to cytoplasmic ratio, are critical for the appearance of lineage-specific differentiation. CONCLUSION Our work corroborates previous studies demonstrating that the cleavage program is causally involved in the spatial segregation and/or activation of factors that give rise to distinct cell types in ctenophore development. These factors are segregated independently to the appropriate lineage at the 8- and the 16-cell stages and have features of a clock, such that comb-plate-like cilia and light-emitting photoproteins appear at roughly the same developmental time in cleavage-arrested embryos as they do in untreated embryos. Nuclear division, which possibly affects DNA-cytoplasmic ratios, appears to be important in the timing of differentiation markers. Evidence suggests that the 60-cell stage, just prior to gastrulation, is the time of zygotic gene activation. Such cleavage-clock-regulated phenomena appear to be widespread amongst the Metazoa and these cellular and molecular developmental mechanisms probably evolved early in metazoan evolution.
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Affiliation(s)
- Antje HL Fischer
- Developmental Biology Unit, European Molecular Biology Laboratory Heidelberg, Meyerhof Strasse 1, Heidelberg 69117, Germany
- current address: Molecular and Cell Biology Department, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA
| | - Kevin Pang
- Kewalo Marine Laboratory, Pacific Biosciences Research Center, University of Hawaii at Manoa, Honolulu, HI, USA
- current address: Sars International Centre for Marine Molecular Biology, Thormøhlensgt. 55, Bergen N-5008, Norway
| | - Jonathan Q Henry
- Department of Cell and Structural Biology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL 61801, USA
| | - Mark Q Martindale
- Whitney Lab for Marine Bioscience, Univ. Florida, 9505 Oceanshore Blvd, St, Augustine, FL 32080, USA
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22
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Cunningham D, Casey ES. Spatiotemporal development of the embryonic nervous system of Saccoglossus kowalevskii. Dev Biol 2013; 386:252-63. [PMID: 24333176 DOI: 10.1016/j.ydbio.2013.12.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 11/21/2013] [Accepted: 12/03/2013] [Indexed: 11/16/2022]
Abstract
Defining the organization and temporal onset of key steps in neurogenesis in invertebrate deuterostomes is critical to understand the evolution of the bilaterian and deuterostome nervous systems. Although recent studies have revealed the organization of the nervous system in adult hemichordates, little attention has been paid to neurogenesis during embryonic development in this third major phylum of deuterostomes. We examine the early events of neural development in the enteropneust hemichordate Saccoglossus kowalevskii by analyzing the expression of 11 orthologs of key genes associated with neurogenesis in an expansive range of bilaterians. Using in situ hybridization (ISH) and RT-PCR, we follow the course of neural development to track the transition of the early embryonic diffuse nervous system to the more regionalized midline nervous system of the adult. We show that in Saccoglossus, neural progenitor markers are expressed maternally and broadly encircle the developing embryo. An increase in their expression and the onset of pan neural markers, indicate that neural specification occurs in late blastulae - early gastrulae. By mid-gastrulation, punctate expression of markers of differentiating neurons encircling the embryo indicate the presence of immature neurons, and at the end of gastrulation when the embryo begins to elongate, markers of mature neurons are expressed. At this stage, expression of a subset of neuronal markers is concentrated along the trunk ventral and dorsal midlines. These data indicate that the diffuse embryonic nervous system of Saccoglossus is transient and quickly reorganizes before hatching to resemble the adult regionalized, centralized nervous system. This regionalization occurs at a much earlier developmental stage than anticipated indicating that centralization is not linked in S. kowalevskii to a lifestyle change of a swimming larva metamorphosing to a crawling worm-like adult.
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Affiliation(s)
- Doreen Cunningham
- Department of Biology, Georgetown University, Washington DC 20057, United States.
| | - Elena Silva Casey
- Department of Biology, Georgetown University, Washington DC 20057, United States
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23
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Rizzi B, Peyrieras N. Towards 3D in silico modeling of the sea urchin embryonic development. J Chem Biol 2013; 7:17-28. [PMID: 24386014 PMCID: PMC3877407 DOI: 10.1007/s12154-013-0101-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 07/22/2013] [Indexed: 11/29/2022] Open
Abstract
Embryogenesis is a dynamic process with an intrinsic variability whose understanding requires the integration of molecular, genetic, and cellular dynamics. Biological circuits function over time at the level of single cells and require a precise analysis of the topology, temporality, and probability of events. Integrative developmental biology is currently looking for the appropriate strategies to capture the intrinsic properties of biological systems. The "-omic" approaches require disruption of the function of the biological circuit; they provide static information, with low temporal resolution and usually with population averaging that masks fast or variable features at the cellular scale and in a single individual. This data should be correlated with cell behavior as cells are the integrators of biological activity. Cellular dynamics are captured by the in vivo microscopy observation of live organisms. This can be used to reconstruct the 3D + time cell lineage tree to serve as the basis for modeling the organism's multiscale dynamics. We discuss here the progress that has been made in this direction, starting with the reconstruction over time of three-dimensional digital embryos from in toto time-lapse imaging. Digital specimens provide the means for a quantitative description of the development of model organisms that can be stored, shared, and compared. They open the way to in silico experimentation and to a more theoretical approach to biological processes. We show, with some unpublished results, how the proposed methodology can be applied to sea urchin species that have been model organisms in the field of classical embryology and modern developmental biology for over a century.
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Affiliation(s)
- Barbara Rizzi
- CNRS-MDAM, UPR 3294 and BioEmergences-IBiSA, Institut de Neurobiologie Alfred Fessard, CNRS, Gif-sur-Yvette, France
- Institut des Systèmes Complexes, 57-59 rue Lhomond, Paris, France
| | - Nadine Peyrieras
- CNRS-MDAM, UPR 3294 and BioEmergences-IBiSA, Institut de Neurobiologie Alfred Fessard, CNRS, Gif-sur-Yvette, France
- Institut des Systèmes Complexes, 57-59 rue Lhomond, Paris, France
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24
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Runcie DE, Garfield DA, Babbitt CC, Wygoda JA, Mukherjee S, Wray GA. Genetics of gene expression responses to temperature stress in a sea urchin gene network. Mol Ecol 2012; 21:4547-62. [PMID: 22856327 PMCID: PMC3866972 DOI: 10.1111/j.1365-294x.2012.05717.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Stress responses play an important role in shaping species distributions and robustness to climate change. We investigated how stress responses alter the contribution of additive genetic variation to gene expression during development of the purple sea urchin, Strongylocentrotus purpuratus, under increased temperatures that model realistic climate change scenarios. We first measured gene expression responses in the embryos by RNA-seq to characterize molecular signatures of mild, chronic temperature stress in an unbiased manner. We found that an increase from 12 to 18 °C caused widespread alterations in gene expression including in genes involved in protein folding, RNA processing and development. To understand the quantitative genetic architecture of this response, we then focused on a well-characterized gene network involved in endomesoderm and ectoderm specification. Using a breeding design with wild-caught individuals, we measured genetic and gene-environment interaction effects on 72 genes within this network. We found genetic or maternal effects in 33 of these genes and that the genetic effects were correlated in the network. Fourteen network genes also responded to higher temperatures, but we found no significant genotype-environment interactions in any of the genes. This absence may be owing to an effective buffering of the temperature perturbations within the network. In support of this hypothesis, perturbations to regulatory genes did not affect the expression of the genes that they regulate. Together, these results provide novel insights into the relationship between environmental change and developmental evolution and suggest that climate change may not expose large amounts of cryptic genetic variation to selection in this species.
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Affiliation(s)
- Daniel E Runcie
- Department of Biology, Duke University, Durham, NC 27708, USA.
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25
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Cameron CB, Bishop CD. Biomineral ultrastructure, elemental constitution and genomic analysis of biomineralization-related proteins in hemichordates. Proc Biol Sci 2012; 279:3041-8. [PMID: 22496191 PMCID: PMC3385480 DOI: 10.1098/rspb.2012.0335] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 03/20/2012] [Indexed: 12/22/2022] Open
Abstract
Here, we report the discovery and characterization of biominerals in the acorn worms Saccoglossus bromophenolosus and Ptychodera flava galapagos (Phylum: Hemichordata). Using electron microscopy, X-ray microprobe analyses and confocal Raman spectroscopy, we show that hemichordate biominerals are small CaCO(3) aragonitic elements restricted to specialized epidermal structures, and in S. bromophenolosus, are apparently secreted by sclerocytes. Investigation of urchin biomineralizing proteins in the translated genome and expressed sequence tag (EST) libraries of Saccoglossus kowalevskii indicates that three members of the urchin MSP-130 family, a carbonic anhydrase and a matrix metaloprotease are present and transcribed during the development of S. kowalevskii. The SM family of proteins is absent from the hemichordate genome. These results increase the number of phyla known to biomineralize and suggest that some of the gene-regulatory 'toolkit', if not mineralized tissue themselves, may have been present in the common ancestor to hemichordates and echinoderms.
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Affiliation(s)
- C B Cameron
- Département de Sciences Biologiques, Université de Montréal, C.P. 6128, Succ. Centre-ville, Montréal, Quebec, Canada, H3C 3J7.
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26
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Feng D, Rittschof D, Orihuela B, Kwok KWH, Stafslien S, Chisholm B. The effects of model polysiloxane and fouling-release coatings on embryonic development of a sea urchin (Arbacia punctulata) and a fish (Oryzias latipes). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2012; 110-111:162-169. [PMID: 22326653 DOI: 10.1016/j.aquatox.2012.01.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 01/04/2012] [Accepted: 01/06/2012] [Indexed: 05/31/2023]
Abstract
In recent decades attention has focused on the development of non-toxic fouling-release coatings based on silicone polymers as an alternative to toxic antifouling coatings. As fouling-release coatings gain market share, they will contribute to environmental contamination by silicones. We report effects of eight model polysiloxane and three commercial foul-release coatings on embryonic development of sea urchins and fish, Japanese medaka. We used model coatings because they have known composition and commercially available components and molecules leaching from these coatings have been partially characterized. The commercial fouling-release coatings are purported to be non-toxic and components are proprietary. Our goal was to expose embryos of well studied model animals to the coatings to determine if the complex mixtures leaching from the coatings impact development. Urchins were chosen because development is rapid and embryos can enter the non-slip layer over surfaces. Medaka was chosen because the female deposits the sticky eggs onto the anal fin and then scrapes them off onto surfaces. Embryos were confined in water over coatings in 24 well plates. Fresh model coatings had no effect on urchin development while commercial fouling-release coatings inhibited development. Fish embryos had delayed hatching, increased mortality of hatchlings and dramatically decreased ability of hatchlings to inflate the swim bladder and reduced hatching success on all coatings. After one-month immersion of coatings in running seawater to simulate initial application in the marine environment, sea urchin embryos died when placed over model silicones. Effects of the commercial coatings were reduced but included retarded development. Effects on fish embryos over leached coating were reduced compared to those of fresh coating and included decreased hatching success, decreased hatchling survival and inability to inflate the swim bladder for commercial coatings. These findings suggest, similar to medical conclusions, compounds leaching from silicone coatings can impact development and the topic deserves study.
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Affiliation(s)
- Danqing Feng
- Duke University Marine Laboratory, Nicholas School of the Environment, Duke University, Beaufort, NC, United States
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27
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Wei Z, Range R, Angerer R, Angerer L. Axial patterning interactions in the sea urchin embryo: suppression of nodal by Wnt1 signaling. Development 2012; 139:1662-9. [PMID: 22438568 DOI: 10.1242/dev.075051] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Wnt and Nodal signaling pathways are required for initial patterning of cell fates along anterior-posterior (AP) and dorsal-ventral (DV) axes, respectively, of sea urchin embryos during cleavage and early blastula stages. These mechanisms are connected because expression of nodal depends on early Wnt/β-catenin signaling. Here, we show that an important subsequent function of Wnt signaling is to control the shape of the nodal expression domain and maintain correct specification of different cell types along the axes of the embryo. In the absence of Wnt1, the posterior-ventral region of the embryo is severely altered during early gastrulation. Strikingly, at this time, nodal and its downstream target genes gsc and bra are expressed ectopically, extending posteriorly to the blastopore. They override the initial specification of posterior-ventral ectoderm and endoderm fates, eliminating the ventral contribution to the gut and displacing the ciliary band dorsally towards, and occasionally beyond, the blastopore. Consequently, in Wnt1 morphants, the blastopore is located at the border of the re-specified posterior-ventral oral ectoderm and by larval stages it is in the same plane near the stomodeum on the ventral side. In normal embryos, a Nodal-dependent process downregulates wnt1 expression in dorsal posterior cells during early gastrulation, focusing Wnt1 signaling to the posterior-ventral region where it suppresses nodal expression. These subsequent interactions between Wnt and Nodal signaling are thus mutually antagonistic, each limiting the range of the other's activity, in order to maintain and stabilize the body plan initially established by those same signaling pathways in the early embryo.
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Affiliation(s)
- Zheng Wei
- National Institute for Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20891, USA
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28
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Lyons DC, Kaltenbach SL, McClay DR. Morphogenesis in sea urchin embryos: linking cellular events to gene regulatory network states. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2011; 1:231-52. [PMID: 23801438 DOI: 10.1002/wdev.18] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Gastrulation in the sea urchin begins with ingression of the primary mesenchyme cells (PMCs) at the vegetal pole of the embryo. After entering the blastocoel the PMCs migrate, form a syncitium, and synthesize the skeleton of the embryo. Several hours after the PMCs ingress the vegetal plate buckles to initiate invagination of the archenteron. That morphogenetic process occurs in several steps. The nonskeletogenic cells produce the initial inbending of the vegetal plate. Endoderm cells then rearrange and extend the length of the gut across the blastocoel to a target near the animal pole. Finally, cells that will form part of the midgut and hindgut are added to complete gastrulation. Later, the stomodeum invaginates from the oral ectoderm and fuses with the foregut to complete the archenteron. In advance of, and during these morphogenetic events, an increasingly complex input of transcription factors controls the specification and the cell biological events that conduct the gastrulation movements.
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Affiliation(s)
- Deirdre C Lyons
- Department of Biology, French Family Science Center, Duke University, Durham, NC, USA
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Cavalieri V, Guarcello R, Spinelli G. Specific expression of a TRIM-containing factor in ectoderm cells affects the skeletal morphogenetic program of the sea urchin embryo. Development 2011; 138:4279-90. [PMID: 21896632 DOI: 10.1242/dev.066480] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the indirect developing sea urchin embryo, the primary mesenchyme cells (PMCs) acquire most of the positional and temporal information from the overlying ectoderm for skeletal initiation and growth. In this study, we characterize the function of the novel gene strim1, which encodes a tripartite motif-containing (TRIM) protein, that adds to the list of genes constituting the epithelial-mesenchymal signaling network. We report that strim1 is expressed in ectoderm regions adjacent to the bilateral clusters of PMCs and that its misexpression leads to severe skeletal abnormalities. Reciprocally, knock down of strim1 function abrogates PMC positioning and blocks skeletogenesis. Blastomere transplantation experiments establish that the defects in PMC patterning, number and skeletal growth depend upon strim1 misexpression in ectoderm cells. Furthermore, clonal expression of strim1 into knocked down embryos locally restores skeletogenesis. We also provide evidence that the Otp and Pax2/5/8 regulators, as well as FGFA, but not VEGF, ligand act downstream to strim1 in ectoderm cells, and that strim1 triggers the expression of the PMC marker sm30, an ectoderm-signaling dependent gene. We conclude that the strim1 function elicits specific gene expression both in ectoderm cells and PMCs to guide the skeletal biomineralization during morphogenesis.
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Affiliation(s)
- Vincenzo Cavalieri
- Dipartimento di Scienze e Tecnologie Molecolari e Biomolecolari STEMBIO, Università di Palermo, Viale delle Scienze Edificio 16, 90128 Palermo, Italy.
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30
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Darras S, Gerhart J, Terasaki M, Kirschner M, Lowe CJ. β-catenin specifies the endomesoderm and defines the posterior organizer of the hemichordate Saccoglossus kowalevskii. Development 2011; 138:959-70. [PMID: 21303849 DOI: 10.1242/dev.059493] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The canonical Wnt/β-catenin pathway is a key regulator of body plan organization and axis formation in metazoans, being involved in germ layer specification, posterior growth and patterning of the anteroposterior axis. Results from animals spanning a wide phylogenetic range suggest that a unifying function of β-catenin in metazoans is to define the posterior/vegetal part of the embryo. Although the specification of vegetal territories (endoderm) by β-catenin has been demonstrated in distantly related animals (cnidarians, a protostome, echinoderms and ascidians), the definition of the posterior part of the embryo is well supported only for vertebrates and planarians. To gain insights into β-catenin functions during deuterostome evolution, we have studied the early development of the direct developing hemichordate Saccoglossus kowalevskii. We show that the zygote is polarized after fertilization along the animal-vegetal axis by cytoplasmic rearrangements resembling the ascidian vegetal contraction. This early asymmetry is translated into nuclear accumulation of β-catenin at the vegetal pole, which is necessary and sufficient to specify endomesoderm. We show that endomesoderm specification is crucial for anteroposterior axis establishment in the ectoderm. The endomesoderm secretes as yet unidentified signals that posteriorize the ectoderm, which would otherwise adopt an anterior fate. Our results point to a conserved function at the base of deuterostomes for β-catenin in germ layer specification and to a causal link in the definition of the posterior part of the embryonic ectoderm by way of activating posteriorizing endomesodermal factors. Consequently, the definition of the vegetal and the posterior regions of the embryo by β-catenin should be distinguished and carefully re-examined.
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Affiliation(s)
- Sébastien Darras
- Institut de Biologie du Développement de Marseille-Luminy, UMR 6216, CNRS, Université de la Méditerranée, Campus de Luminy, Marseille Cedex 09, France.
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31
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Saudemont A, Haillot E, Mekpoh F, Bessodes N, Quirin M, Lapraz F, Duboc V, Röttinger E, Range R, Oisel A, Besnardeau L, Wincker P, Lepage T. Ancestral regulatory circuits governing ectoderm patterning downstream of Nodal and BMP2/4 revealed by gene regulatory network analysis in an echinoderm. PLoS Genet 2010; 6:e1001259. [PMID: 21203442 PMCID: PMC3009687 DOI: 10.1371/journal.pgen.1001259] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2010] [Accepted: 11/22/2010] [Indexed: 12/13/2022] Open
Abstract
Echinoderms, which are phylogenetically related to vertebrates and produce large numbers of transparent embryos that can be experimentally manipulated, offer many advantages for the analysis of the gene regulatory networks (GRN) regulating germ layer formation. During development of the sea urchin embryo, the ectoderm is the source of signals that pattern all three germ layers along the dorsal-ventral axis. How this signaling center controls patterning and morphogenesis of the embryo is not understood. Here, we report a large-scale analysis of the GRN deployed in response to the activity of this signaling center in the embryos of the Mediterranean sea urchin Paracentrotus lividus, in which studies with high spatial resolution are possible. By using a combination of in situ hybridization screening, overexpression of mRNA, recombinant ligand treatments, and morpholino-based loss-of-function studies, we identified a cohort of transcription factors and signaling molecules expressed in the ventral ectoderm, dorsal ectoderm, and interposed neurogenic ("ciliary band") region in response to the known key signaling molecules Nodal and BMP2/4 and defined the epistatic relationships between the most important genes. The resultant GRN showed a number of striking features. First, Nodal was found to be essential for the expression of all ventral and dorsal marker genes, and BMP2/4 for all dorsal genes. Second, goosecoid was identified as a central player in a regulatory sub-circuit controlling mouth formation, while tbx2/3 emerged as a critical factor for differentiation of the dorsal ectoderm. Finally, and unexpectedly, a neurogenic ectoderm regulatory circuit characterized by expression of "ciliary band" genes was triggered in the absence of TGF beta signaling. We propose a novel model for ectoderm regionalization, in which neural ectoderm is the default fate in the absence of TGF beta signaling, and suggest that the stomodeal and neural subcircuits that we uncovered may represent ancient regulatory pathways controlling embryonic patterning.
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Affiliation(s)
- Alexandra Saudemont
- UMR 7009 CNRS, Université de Pierre et Marie Curie (Paris 6), Observatoire Oceanologique, Villefranche-sur-Mer, France
| | - Emmanuel Haillot
- UMR 7009 CNRS, Université de Pierre et Marie Curie (Paris 6), Observatoire Oceanologique, Villefranche-sur-Mer, France
| | - Flavien Mekpoh
- UMR 7009 CNRS, Université de Pierre et Marie Curie (Paris 6), Observatoire Oceanologique, Villefranche-sur-Mer, France
| | - Nathalie Bessodes
- UMR 7009 CNRS, Université de Pierre et Marie Curie (Paris 6), Observatoire Oceanologique, Villefranche-sur-Mer, France
| | - Magali Quirin
- UMR 7009 CNRS, Université de Pierre et Marie Curie (Paris 6), Observatoire Oceanologique, Villefranche-sur-Mer, France
| | - François Lapraz
- UMR 7009 CNRS, Université de Pierre et Marie Curie (Paris 6), Observatoire Oceanologique, Villefranche-sur-Mer, France
| | - Véronique Duboc
- UMR 7009 CNRS, Université de Pierre et Marie Curie (Paris 6), Observatoire Oceanologique, Villefranche-sur-Mer, France
| | - Eric Röttinger
- UMR 7009 CNRS, Université de Pierre et Marie Curie (Paris 6), Observatoire Oceanologique, Villefranche-sur-Mer, France
| | - Ryan Range
- UMR 7009 CNRS, Université de Pierre et Marie Curie (Paris 6), Observatoire Oceanologique, Villefranche-sur-Mer, France
| | - Arnaud Oisel
- UMR 7009 CNRS, Université de Pierre et Marie Curie (Paris 6), Observatoire Oceanologique, Villefranche-sur-Mer, France
| | - Lydia Besnardeau
- UMR 7009 CNRS, Université de Pierre et Marie Curie (Paris 6), Observatoire Oceanologique, Villefranche-sur-Mer, France
| | - Patrick Wincker
- Génoscope (CEA), UMR8030, CNRS and Université d'Evry, Evry, France
| | - Thierry Lepage
- UMR 7009 CNRS, Université de Pierre et Marie Curie (Paris 6), Observatoire Oceanologique, Villefranche-sur-Mer, France
- * E-mail:
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Yajima M, Umeda R, Fuchikami T, Kataoka M, Sakamoto N, Yamamoto T, Akasaka K. Implication of HpEts in gene regulatory networks responsible for specification of sea urchin skeletogenic primary mesenchyme cells. Zoolog Sci 2010; 27:638-46. [PMID: 20695779 DOI: 10.2108/zsj.27.638] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The large micromeres of the 32-cell stage of sea urchin embryos are autonomously specified and differentiate into primary mesenchyme cells (PMCs), giving rise to the skeletogenic cells. We previously demonstrated that HpEts, an ets-related transcription factor, plays an essential role in the specification of PMCs in sea urchin embryos. In order to clarify the function of HpEts in the gene regulatory network involved in PMC specification, we analyzed the zygotic expression pattern and the cis-regulatory region of HpEts, and examined the activity of the HpEts protein as a transcription factor. Intron-based PCR reveals that zygotic expression of HpEts starts at the cleavage stage, and that the rate of transcription reaches maximum at the unhatched blastula stage. A series of progressive deletions of the fragments from -4.2 kbp to +1206 bp of the HpEts, which directs PMC-specific expression, caused a gradual decrease in the specificity, implying that coordination of several cis-regulatory elements regulates the expression in PMCs. A minimum cis-element required for the temporal expression is located within a 10 bp from -243 bp to -234 bp. The HpEts protein remains in the cytoplasm of entire embryonic cells in the cleavage stage. At the unhatched blastula stage, the HpEts protein translocates into the nucleus in presumptive PMCs. Transactivation assays demonstrate that the HpEts protein activates a promoter of Spicule Matrix Protein 50 (SM50), which is a target of HpEts, which binds to the regulatory region of SM50.
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Affiliation(s)
- Mamiko Yajima
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA
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Wei Z, Yaguchi J, Yaguchi S, Angerer RC, Angerer LM. The sea urchin animal pole domain is a Six3-dependent neurogenic patterning center. Development 2009; 136:1179-89. [PMID: 19270175 PMCID: PMC2685935 DOI: 10.1242/dev.032300] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/29/2009] [Indexed: 11/20/2022]
Abstract
Two major signaling centers have been shown to control patterning of sea urchin embryos. Canonical Wnt signaling in vegetal blastomeres and Nodal signaling in presumptive oral ectoderm are necessary and sufficient to initiate patterning along the primary and secondary axes, respectively. Here we define and characterize a third patterning center, the animal pole domain (APD), which contains neurogenic ectoderm, and can oppose Wnt and Nodal signaling. The regulatory influence of the APD is normally restricted to the animal pole region, but can operate in most cells of the embryo because, in the absence of Wnt and Nodal, the APD expands throughout the embryo. We have identified many constituent APD regulatory genes expressed in the early blastula and have shown that expression of most of them requires Six3 function. Furthermore, Six3 is necessary for the differentiation of diverse cell types in the APD, including the neurogenic animal plate and immediately flanking ectoderm, indicating that it functions at or near the top of several APD gene regulatory networks. Remarkably, it is also sufficient to respecify the fates of cells in the rest of the embryo, generating an embryo consisting of a greatly expanded, but correctly patterned, APD. A fraction of the large group of Six3-dependent regulatory proteins are orthologous to those expressed in the vertebrate forebrain, suggesting that they controlled formation of the early neurogenic domain in the common deuterostome ancestor of echinoderms and vertebrates.
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Affiliation(s)
- Zheng Wei
- National Institute for Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
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34
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Abstract
The most animal part of the ciliated band of sea urchin larvae, the animal plate, is a specialized region in which elongated cells form long and non-beating cilia. To learn how this region is specified, animal halves were isolated from the early cleavage to pregastrulation stages. As is well known, the animal half that is isolated at the eight-cell stage develops into a 'dauerblastula', which forms long and non-beating cilia all around the surface. The region with long cilia, however, became restricted toward the animal pole when separation was delayed. If separated before primary mesenchyme ingression, even a small animal-pole-side fragment formed a normal-sized animal plate. Thus, the prospective animal plate region is gradually restricted by some signal from the vegetal hemisphere, and the specification process terminates before the mesenchyme blastula stage. It was also known that a normal-sized animal plate was formed in micromere-less embryos, indicating that the signal does not depend on micromeres or their descendants. Further, the animal-pole-side fragments were isolated from embryos in which the third cleavage plane was shifted toward the vegetal pole. They formed a normal-sized animal plate, containing more than 75% of the egg volume from the animal pole. This indicates that the egg cytoplasm delivered to veg1-lineage blastomeres plays an important role in the animal plate specification. Interestingly, the an1-less embryo formed long and non-beating cilia at its top region, but thickening did not occur. The cytoplasm near the animal pole might contain some factors necessary for the animal plate to become thick.
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Affiliation(s)
- Hiroki Sasaki
- Department of Biology, Faculty of Science, Ehime University, 2-5, Bunkyo-Cho, Matsuyama 790-8577, Japan
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35
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Ettensohn CA. Lessons from a gene regulatory network: echinoderm skeletogenesis provides insights into evolution, plasticity and morphogenesis. Development 2009; 136:11-21. [PMID: 19060330 DOI: 10.1242/dev.023564] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Significant new insights have emerged from the analysis of a gene regulatory network (GRN) that underlies the development of the endoskeleton of the sea urchin embryo. Comparative studies have revealed ways in which this GRN has been modified (and conserved) during echinoderm evolution, and point to mechanisms associated with the evolution of a new cell lineage. The skeletogenic GRN has also recently been used to study the long-standing problem of developmental plasticity. Other recent findings have linked this transcriptional GRN to morphoregulatory proteins that control skeletal anatomy. These new studies highlight powerful new ways in which GRNs can be used to dissect development and the evolution of morphogenesis.
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Affiliation(s)
- Charles A Ettensohn
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA.
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Satoh K, Kominami T. Initial observation of potential factors involved in the specification process of oral-aboral axis in the sand dollar Scaphechinus mirabilis. Dev Growth Differ 2008; 50:675-87. [PMID: 18826473 DOI: 10.1111/j.1440-169x.2008.01065.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To elucidate factors involved in the oral-aboral axis specification, several observations and experiments were undertaken using the sand dollar Scaphechinus mirabilis. Unlike in Strongylcentrotus purpuratus, localization of mitochondria was not detected in unfertilized eggs. After fertilization, however, the bulk of mitochondria became localized to the opposite side of sperm entry. The first cleavage divided this mitochondrial cluster into daughter blastomeres. On the other hand, a second cleavage produced daughter blastomeres containing quite different amounts of mitochondria. To know whether such mitochondrial localization affects the oral-aboral axis specification, 4-cell-stage embryos were separated along the second cleavage plane. Although both half embryos developed into morphologically normal plutei, some differences, such as the number of pigment cells, were noticed between the siblings. In contrast, cell tracing revealed that the first cleavage separated the oral from the aboral part in most cases, indicating that the unequal distribution of mitochondria is not critical for the oral-aboral axis specification. Further, stained and non-stained half embryo fragments were combined. Such combined embryos developed into normal plutei with a single oral-aboral axis. The plane dividing labeled and non-labeled parts were incident, oblique or perpendicular to the median plane of the combined embryo, and the appearance frequencies of those labeling patterns were similar to those obtained by cell tracing in intact embryos. Interestingly, the half fragments derived from embryos inseminated earlier showed a tendency to form the oral part. These suggest that several factors as well as the localized cytoplasmic components would be involved in the specification process of oral-aboral axis.
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Affiliation(s)
- Kanehide Satoh
- Department of Biology, Faculty of Science, Ehime University, 2-5, Bunkyo-Cho, Matsuyama, 790-8577, Japan
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37
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Cavalieri V, Di Bernardo M, Anello L, Spinelli G. cis-Regulatory sequences driving the expression of the Hbox12 homeobox-containing gene in the presumptive aboral ectoderm territory of the Paracentrotus lividus sea urchin embryo. Dev Biol 2008; 321:455-69. [PMID: 18585371 DOI: 10.1016/j.ydbio.2008.06.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 05/23/2008] [Accepted: 06/03/2008] [Indexed: 11/17/2022]
Abstract
Embryonic development is coordinated by networks of evolutionary conserved regulatory genes encoding transcription factors and components of cell signalling pathways. In the sea urchin embryo, a number of genes encoding transcription factors display territorial restricted expression. Among these, the zygotic Hbox12 homeobox gene is transiently transcribed in a limited number of cells of the animal-lateral half of the early Paracentrotus lividus embryo, whose descendants will constitute part of the ectoderm territory. To obtain insights on the regulation of Hbox12 expression, we have explored the cis-regulatory apparatus of the gene. In this paper, we show that the intergenic region of the tandem Hbox12 repeats drives GFP expression in the presumptive aboral ectoderm and that a 234 bp fragment, defined aboral ectoderm (AE) module, accounts for the restricted expression of the transgene. Within this module, a consensus sequence for a Sox factor and the binding of the Otx activator are both required for correct Hbox12 gene expression. Spatial restriction to the aboral ectoderm is achieved by a combination of different repressive sequence elements. Negative sequence elements necessary for repression in the endomesoderm map within the most upstream 60 bp region and nearby the Sox binding site. Strikingly, a Myb-like consensus is necessary for repression in the oral ectoderm, while down-regulation at the gastrula stage depends on a GA-rich region. These results suggest a role for Hbox12 in aboral ectoderm specification and represent our first attempt in the identification of the gene regulatory circuits involved in this process.
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Affiliation(s)
- Vincenzo Cavalieri
- Dipartimento di Biologia Cellulare e dello Sviluppo A. Monroy, Università di Palermo, Viale delle Scienze Edificio 16, 90128 Palermo, Italy
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Romancino DP, Montana G, Cavalieri V, Spinelli G, Di Carlo M. EGFR signalling is required for Paracentrotus lividus endomesoderm specification. Arch Biochem Biophys 2008; 474:167-74. [PMID: 18395511 DOI: 10.1016/j.abb.2008.03.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 03/06/2008] [Accepted: 03/07/2008] [Indexed: 10/22/2022]
Abstract
The EGFR pathway is critical for cell fate specification throughout the development of several organisms. Here we identified in sea urchin an EGFR-related antigen maternally expressed and showing a dynamic pattern of localization during development. To investigate the role played by the EGFR in Paracentrotus lividus development we blocked its activity by using the EGFR kinase inhibitor AG1478. This treatment produces decrease of EGFR phosphorylation, and embryos with various defects especially in the endomesoderm territory until to obtain an animalized phenotype. These effects are rescued by the addition of TGF-alpha, an EGFR ligand. The role played by EGFR-like along the animal/vegetal axis was also detected, after AG1478 treatment, by the extended distribution of HE and decreased nuclearization of beta-catenin in vegetal cells. Moreover, inhibition of EGFR-like reduced ERK phosphorylation, necessary for cell fate specification in the micromeres and their derivates. Taken together these results indicate that EGFR-like activity is required both for A/V axis formation and endomesoderm differentiation.
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Affiliation(s)
- Daniele P Romancino
- Istituto di Biomedicina ed Immunologia Molecolare (IBIM) "Alberto Monroy", CNR, sez. Biologia dello Sviluppo, via Ugo La Malfa 153, 90146 Palermo, PA, Italy
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39
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Yaguchi S, Yaguchi J, Angerer RC, Angerer LM. A Wnt-FoxQ2-nodal pathway links primary and secondary axis specification in sea urchin embryos. Dev Cell 2008; 14:97-107. [PMID: 18194656 DOI: 10.1016/j.devcel.2007.10.012] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Revised: 09/18/2007] [Accepted: 10/19/2007] [Indexed: 12/31/2022]
Abstract
The primary (animal-vegetal) (AV) and secondary (oral-aboral) (OA) axes of sea urchin embryos are established by distinct regulatory pathways. However, because experimental perturbations of AV patterning also invariably disrupt OA patterning and radialize the embryo, these two axes must be mechanistically linked. Here we show that FoxQ2, which is progressively restricted to the animal plate during cleavage stages, provides this linkage. When AV patterning is prevented by blocking the nuclear function of beta-catenin, the animal plate where FoxQ2 is expressed expands throughout the future ectoderm, and expression of nodal, which initiates OA polarity, is blocked. Surprisingly, nodal transcription and OA differentiation are rescued simply by inhibiting FoxQ2 translation. Therefore, restriction of FoxQ2 to the animal plate is a crucial element of canonical Wnt signaling that coordinates patterning along the AV axis with the initiation of OA specification.
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Affiliation(s)
- Shunsuke Yaguchi
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA.
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40
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Hayward P, Kalmar T, Arias AM. Wnt/Notch signalling and information processing during development. Development 2008; 135:411-24. [PMID: 18192283 DOI: 10.1242/dev.000505] [Citation(s) in RCA: 229] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The Wnt and Notch signalling pathways represent two major channels of communication used by animal cells to control their identities and behaviour during development. A number of reports indicate that their activities are closely intertwined during embryonic development. Here, we review the evidence for this relationship and suggest that Wnt and Notch ('Wntch') signalling act as components of an integrated device that, rather than defining the fate of a cell, determines the probability that a cell will adopt that fate.
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Affiliation(s)
- Penelope Hayward
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
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41
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Lambert JD. Mesoderm in spiralians: the organizer and the 4d cell. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2008; 310:15-23. [PMID: 17577229 DOI: 10.1002/jez.b.21176] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The Spiralia is a clade of protostome invertebrate phyla that share a highly conserved mode of early development. Spiralian development is characterized by regularities in the arrangement of early cleavages, the fates of the cells that are produced by these divisions, and the development of the distinctive trochophore larva. Because of the strong conservation in early development, homologies can be identified between cells in divergent taxa. Some of the most striking examples of conservation in the spiralian embryo are in the cells that generate the mesoderm. The specification of the mesodermal precursors has been well characterized by embryological approaches, and recently the molecular mechanisms of mesoderm specification are starting to be elucidated. This review examines the development of mesoderm in spiralians in a comparative context, with particular focus on the relationship between the mesendodermal cell 4d and the embryonic organizer.
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Affiliation(s)
- J David Lambert
- Department of Biology, University of Rochester, Rochester, New York 14627, USA.
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42
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Semenova MN, Tsyganov DV, Yakubov AP, Kiselyov AS, Semenov VV. A synthetic derivative of plant allylpolyalkoxybenzenes induces selective loss of motile cilia in sea urchin embryos. ACS Chem Biol 2008; 3:95-100. [PMID: 18278850 DOI: 10.1021/cb700163q] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Polyalkoxybenzenes are plant components displaying a wide range of biological activities. In these studies, we synthesized apiol and dillapiol isoxazoline analogues of combretastatins and evaluated their effect on sea urchin embryos. We have shown that p-methoxyphenyl isoxazoline caused sea urchin embryo immobilization due to the selective excision of motile cilia, whereas long immotile sensory cilia of apical tuft remained intact. This effect was completely reversed by washing the embryos. The compound did not alter cell division, blastulae hatching, and larval morphogenesis. In our hands, the molecule would serve as a convenient tool for in vivo studying morphogenetic processes in the sea urchin embryo. We anticipate that both the assay and the described derivative could be used for studies in ciliary function in embryogenesis.
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Affiliation(s)
- Marina N. Semenova
- Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
| | - Dmitry V. Tsyganov
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Alexandr P. Yakubov
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Alexandr S. Kiselyov
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Victor V. Semenov
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
- Chemical Block Ltd., Limassol, Cyprus
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Ettensohn CA, Kitazawa C, Cheers MS, Leonard JD, Sharma T. Gene regulatory networks and developmental plasticity in the early sea urchin embryo: alternative deployment of the skeletogenic gene regulatory network. Development 2007; 134:3077-87. [PMID: 17670786 DOI: 10.1242/dev.009092] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cell fates in the sea urchin embryo are remarkably labile, despite the fact that maternal polarity and zygotic programs of differential gene expression pattern the embryo from the earliest stages. Recent work has focused on transcriptional gene regulatory networks (GRNs) deployed in specific embryonic territories during early development. The micromere-primary mesenchyme cell(PMC) GRN drives the development of the embryonic skeleton. Although normally deployed only by presumptive PMCs, every lineage of the early embryo has the potential to activate this pathway. Here, we focus on one striking example of regulative activation of the skeletogenic GRN; the transfating of non-skeletogenic mesoderm (NSM) cells to a PMC fate during gastrulation. We show that transfating is accompanied by the de novo expression of terminal,biomineralization-related genes in the PMC GRN, as well as genes encoding two upstream transcription factors, Lvalx1 and Lvtbr. We report that Lvalx1, a key component of the skeletogenic GRN in the PMC lineage, plays an essential role in the regulative pathway both in NSM cells and in animal blastomeres. MAPK signaling is required for the expression of Lvalx1 and downstream skeletogenic genes in NSM cells, mirroring its role in the PMC lineage. We also demonstrate that Lvalx1 regulates the signal from PMCs that normally suppresses NSM transfating. Significantly,misexpression of Lvalx1 in macromeres (the progenitors of NSM cells)is sufficient to activate the skeletogenic GRN. We suggest that NSM cells normally deploy a basal mesodermal pathway and require only an Lvalx1-mediated sub-program to express a PMC fate. Finally, we provide evidence that, in contrast to the normal pathway, activation of the skeletogenic GRN in NSM cells is independent of Lvpmar1. Our studies reveal that, although most features of the micromere-PMC GRN are recapitulated in transfating NSM cells, different inputs activate this GRN during normal and regulative development.
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Affiliation(s)
- Charles A Ettensohn
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA.
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44
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Angerer LM, Kenny AP, Newman LA, Angerer RC. Mutual antagonism of SoxB1 and canonical Wnt signaling in sea urchin embryos. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/sita.200600110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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45
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Wu SY, McClay DR. The Snail repressor is required for PMC ingression in the sea urchin embryo. Development 2007; 134:1061-70. [PMID: 17287249 PMCID: PMC3045531 DOI: 10.1242/dev.02805] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In metazoans, the epithelial-mesenchymal transition (EMT) is a crucial process for placing the mesoderm beneath the ectoderm. Primary mesenchyme cells (PMCs) at the vegetal pole of the sea urchin embryo ingress into the floor of the blastocoele from the blastula epithelium and later become the skeletogenic mesenchyme. This ingression movement is a classic EMT during which the PMCs penetrate the basal lamina, lose adherens junctions and migrate into the blastocoele. Later, secondary mesenchyme cells (SMCs) also enter the blastocoele via an EMT, but they accompany the invagination of the archenteron initially, in much the same way vertebrate mesenchyme enters the embryo along with endoderm. Here we identify a sea urchin ortholog of the Snail transcription factor, and focus on its roles regulating EMT during PMC ingression. Functional knockdown analyses of Snail in whole embryos and chimeras demonstrate that Snail is required in micromeres for PMC ingression. Snail represses the transcription of cadherin, a repression that appears evolutionarily conserved throughout the animal kingdom. Furthermore, Snail expression is required for endocytosis of cadherin, a cellular activity that accompanies PMC ingression. Perturbation studies position Snail in the sea urchin micromere-PMC gene regulatory network (GRN), downstream of Pmar1 and Alx1, and upstream of several PMC-expressed proteins. Taken together, our findings indicate that Snail plays an essential role in PMCs to control the EMT process, in part through its repression of cadherin expression during PMC ingression, and in part through its role in the endocytosis that helps convert an epithelial cell to a mesenchyme cell.
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Duboc V, Lepage T. A conserved role for the nodal signaling pathway in the establishment of dorso-ventral and left–right axes in deuterostomes. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2007; 310:41-53. [PMID: 16838294 DOI: 10.1002/jez.b.21121] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Nodal factors play crucial roles during embryogenesis of chordates. They have been implicated in a number of developmental processes, including mesoderm and endoderm formation and patterning of the embryo along the anterior-posterior and left-right axes. We have analyzed the function of the Nodal signaling pathway during the embryogenesis of the sea urchin, a non-chordate organism. We found that Nodal signaling plays a central role in axis specification in the sea urchin, but surprisingly, its first main role appears to be in ectoderm patterning and not in specification of the endoderm and mesoderm germ layers as in vertebrates. Starting at the early blastula stage, sea urchin nodal is expressed in the presumptive oral ectoderm where it controls the formation of the oral-aboral axis. A second conserved role for nodal signaling during vertebrate evolution is its involvement in the establishment of left-right asymmetries. Sea urchin larvae exhibit profound left-right asymmetry with the formation of the adult rudiment occurring only on the left side. We found that a nodal/lefty/pitx2 gene cassette regulates left-right asymmetry in the sea urchin but that intriguingly, the expression of these genes is reversed compared to vertebrates. We have shown that Nodal signals emitted from the right ectoderm of the larva regulate the asymmetrical morphogenesis of the coelomic pouches by inhibiting rudiment formation on the right side of the larva. This result shows that the mechanisms responsible for patterning the left-right axis are conserved in echinoderms and that this role for nodal is conserved among the deuterostomes. We will discuss the implications regarding the reference axes of the sea urchin and the ancestral function of the nodal gene in the last section of this review.
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Affiliation(s)
- Véronique Duboc
- UMR 7009 CNRS, Université de Paris VI, Biologie du Développement, Observatoire Oceanologique, 06230 Villefranche-sur-Mer, France.
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Wei Z, Angerer RC, Angerer LM. A database of mRNA expression patterns for the sea urchin embryo. Dev Biol 2006; 300:476-84. [PMID: 17007833 PMCID: PMC1762123 DOI: 10.1016/j.ydbio.2006.08.034] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Revised: 08/10/2006] [Accepted: 08/15/2006] [Indexed: 01/26/2023]
Abstract
We present an initial characterization of a database that contains temporal expression profiles of sequences found in 35,282 gene predictions within the sea urchin genome. The relative RNA abundance for each sequence was determined at 5 key stages of development using high-density oligonucleotide microarrays that were hybridized with populations of polyA+ RNA sequence. These stages were two-cell, which represents maternal RNA, early blastula, the time at which major tissue territories are specified, early and late gastrula, during which important morphogenetic events occur, and the pluteus larva, which marks the culmination of pre-feeding embryogenesis. We provide evidence that the microarray reliably reports the temporal profiles for the large majority of predicted genes, as shown by comparison to data for many genes with known expression patterns. The sensitivity of this assay allows detection of mRNAs whose concentration is only several hundred copies/embryo. The temporal expression profiles indicate that 5% of the gene predictions encode mRNAs that are found only in the maternal population while 24% are embryo-specific. Further, we find that the concentration of >80% of different mRNAs is modulated by more than a factor of 3 during development. Along with the annotated sea urchin genome sequence and the whole-genome tiling array (the transcriptome, Samanta, M., Tongprasit, W., Istrrail, S., Cameron, R., Tu, Q., Davidson, E., Stolc, V., in press. A high-resolution transcriptome map of the sea urchin embryo. Science), this database proves a valuable resource for designing experiments to test the function of specific genes during development.
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Affiliation(s)
- Zheng Wei
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
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Salazar-Ciudad I. On the origins of morphological disparity and its diverse developmental bases. Bioessays 2006; 28:1112-22. [PMID: 17041901 DOI: 10.1002/bies.20482] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
It has been repeatedly claimed that morphological novelties are an unresolved problem in evolutionary theory. Several definitions of novelty exist but most emphasize that novelties imply qualitative changes on the phenotype and not the quantitative gradual changes favored in the neo-Darwinian approach to evolutionary theory. This article discusses how the concept of novelty is used to describe aspects of morphological evolution that are not satisfactorily explained under the modern synthesis. In this article, it is suggested that there is a repertoire of morphological changes rather than two discrete qualitatively different types of morphological change. How these different types of morphological changes can be understood from the diversity of developmental mechanisms existing in animal development is explored. Specifically, it is proposed that animal morphology and its variation can be understood from the spatial patterns produced by a set of basic developmental mechanisms and their combination. Some specific examples of these kinds of morphologic changes are explained.
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Affiliation(s)
- Isaac Salazar-Ciudad
- Developmental Biology Program, Institute of Biotechnology, PO Box 56, FIN-00014, University of Helsinki, Helsinki, Finland.
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Lapraz F, Röttinger E, Duboc V, Range R, Duloquin L, Walton K, Wu SY, Bradham C, Loza MA, Hibino T, Wilson K, Poustka A, McClay D, Angerer L, Gache C, Lepage T. RTK and TGF-beta signaling pathways genes in the sea urchin genome. Dev Biol 2006; 300:132-52. [PMID: 17084834 DOI: 10.1016/j.ydbio.2006.08.048] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2006] [Revised: 08/16/2006] [Accepted: 08/16/2006] [Indexed: 12/23/2022]
Abstract
The Receptor Tyrosine kinase (RTK) and TGF-beta signaling pathways play essential roles during development in many organisms and regulate a plethora of cellular responses. From the genome sequence of Strongylocentrotus purpuratus, we have made an inventory of the genes encoding receptor tyrosine kinases and their ligands, and of the genes encoding cytokines of the TGF-beta superfamily and their downstream components. The sea urchin genome contains at least 20 genes coding for canonical receptor tyrosine kinases. Seventeen of the nineteen vertebrate RTK families are represented in the sea urchin. Fourteen of these RTK among which ALK, CCK4/PTK7, DDR, EGFR, EPH, LMR, MET/RON, MUSK, RET, ROR, ROS, RYK, TIE and TRK are present as single copy genes while pairs of related genes are present for VEGFR, FGFR and INSR. Similarly, nearly all the subfamilies of TGF-beta ligands identified in vertebrates are present in the sea urchin genome including the BMP, ADMP, GDF, Activin, Myostatin, Nodal and Lefty, as well as the TGF-beta sensu stricto that had not been characterized in invertebrates so far. Expression analysis indicates that the early expression of nodal, BMP2/4 and lefty is restricted to the oral ectoderm reflecting their role in providing positional information along the oral-aboral axis of the embryo. The coincidence between the emergence of TGF-beta-related factors such as Nodal and Lefty and the emergence of the deuterostome lineage strongly suggests that the ancestral function of Nodal could have been related to the secondary opening of the mouth which characterizes this clade, a hypothesis supported by functional data in the extant species. The sea urchin genome contains 6 genes encoding TGF-beta receptors and 4 genes encoding prototypical Smad proteins. Furthermore, most of the transcriptional activators and repressors shown to interact with Smads in vertebrates have orthologues in echinoderms. Finally, the sea urchin genome contains an almost complete repertoire of genes encoding extracellular modulators of BMP signaling including Chordin, Noggin, Sclerotin, SFRP, Gremlin, DAN and Twisted gastrulation. Taken together, these findings indicate that the sea urchin complement of genes of the RTK and TGF-beta signaling pathways is qualitatively very similar to the repertoire present in vertebrates, and that these genes are part of the common genetool kit for intercellular signaling of deuterostomes.
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Affiliation(s)
- François Lapraz
- UMR 7009 CNRS, Université Pierre et Marie Curie-Paris 6, Observatoire Oceanologique, 06230 Villefranche-sur-Mer, France
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Gebhardt R, Ueberham E. Zonal gene expression in murine liver: Are tumors helping us to solve the mystery? Hepatology 2006; 44:512; author reply 512-3. [PMID: 16871579 DOI: 10.1002/hep.21276] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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