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Jackson EW, Romero E, Kling S, Lee Y, Tjeerdema E, Hamdoun A. Stable germline transgenesis using the Minos Tc1/mariner element in the sea urchin Lytechinus pictus. Development 2024; 151:dev202991. [PMID: 39023164 DOI: 10.1242/dev.202991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Accepted: 07/02/2024] [Indexed: 07/20/2024]
Abstract
Stable transgenesis is a transformative tool in model organism biology. Although the sea urchin is one of the oldest animal models in cell and developmental biology, studies in this animal have largely relied on transient manipulation of wild animals, without a strategy for stable transgenesis. Here, we build on recent progress to develop a more genetically tractable sea urchin species, Lytechinus pictus, and establish a robust transgene integration method. Three commonly used transposons (Minos, Tol2 and piggyBac) were tested for non-autonomous transposition, using plasmids containing a polyubiquitin promoter upstream of a H2B-mCerulean nuclear marker. Minos was the only transposable element that resulted in significant expression beyond metamorphosis. F0 animals were raised to sexual maturity, and spawned to determine germline integration and transgene inheritance frequency, and to characterize expression patterns of the transgene in F1 progeny. The results demonstrate transgene transmission through the germline, the first example of a germline transgenic sea urchin and, indeed, of any echinoderm. This milestone paves the way for the generation of diverse transgenic resources that will dramatically enhance the utility, reproducibility and efficiency of sea urchin research.
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Affiliation(s)
- Elliot W Jackson
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92037, USA
| | - Emilio Romero
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92037, USA
| | - Svenja Kling
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92037, USA
| | - Yoon Lee
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92037, USA
| | - Evan Tjeerdema
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92037, USA
| | - Amro Hamdoun
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92037, USA
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2
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Morandell J, Monziani A, Lazioli M, Donzel D, Döring J, Oss Pegorar C, D'Anzi A, Pellegrini M, Mattiello A, Bortolotti D, Bergonzoni G, Tripathi T, Mattis VB, Kovalenko M, Rosati J, Dieterich C, Dassi E, Wheeler VC, Ellederová Z, Wilusz JE, Viero G, Biagioli M. CircHTT(2,3,4,5,6) - co-evolving with the HTT CAG-repeat tract - modulates Huntington's disease phenotypes. MOLECULAR THERAPY. NUCLEIC ACIDS 2024; 35:102234. [PMID: 38974999 PMCID: PMC11225910 DOI: 10.1016/j.omtn.2024.102234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Accepted: 05/29/2024] [Indexed: 07/09/2024]
Abstract
Circular RNA (circRNA) molecules have critical functions during brain development and in brain-related disorders. Here, we identified and validated a circRNA, circHTT(2,3,4,5,6), stemming from the Huntington's disease (HD) gene locus that is most abundant in the central nervous system (CNS). We uncovered its evolutionary conservation in diverse mammalian species, and a correlation between circHTT(2,3,4,5,6) levels and the length of the CAG-repeat tract in exon-1 of HTT in human and mouse HD model systems. The mouse orthologue, circHtt(2,3,4,5,6), is expressed during embryogenesis, increases during nervous system development, and is aberrantly upregulated in the presence of the expanded CAG tract. While an IRES-like motif was predicted in circH TT (2,3,4,5,6), the circRNA does not appear to be translated in adult mouse brain tissue. Nonetheless, a modest, but consistent fraction of circHtt(2,3,4,5,6) associates with the 40S ribosomal subunit, suggesting a possible role in the regulation of protein translation. Finally, circHtt(2,3,4,5,6) overexpression experiments in HD-relevant STHdh striatal cells revealed its ability to modulate CAG expansion-driven cellular defects in cell-to-substrate adhesion, thus uncovering an unconventional modifier of HD pathology.
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Affiliation(s)
- Jasmin Morandell
- NeuroEpigenetics Laboratory, Department of Cellular, Computational, and Integrative Biology - CIBIO, University of Trento, 38123 Trento, Italy
| | - Alan Monziani
- NeuroEpigenetics Laboratory, Department of Cellular, Computational, and Integrative Biology - CIBIO, University of Trento, 38123 Trento, Italy
| | - Martina Lazioli
- NeuroEpigenetics Laboratory, Department of Cellular, Computational, and Integrative Biology - CIBIO, University of Trento, 38123 Trento, Italy
| | - Deborah Donzel
- Institute of Biophysics Unit at Trento, National Research Council - CNR, 38123 Trento, Italy
| | - Jessica Döring
- NeuroEpigenetics Laboratory, Department of Cellular, Computational, and Integrative Biology - CIBIO, University of Trento, 38123 Trento, Italy
| | - Claudio Oss Pegorar
- NeuroEpigenetics Laboratory, Department of Cellular, Computational, and Integrative Biology - CIBIO, University of Trento, 38123 Trento, Italy
| | - Angela D'Anzi
- Cellular Reprogramming Unit Fondazione IRCCS, Casa Sollievo Della Sofferenza, Viale dei Cappuccini 1, 71013 San Giovanni Rotondo, FG, Italy
| | - Miguel Pellegrini
- NeuroEpigenetics Laboratory, Department of Cellular, Computational, and Integrative Biology - CIBIO, University of Trento, 38123 Trento, Italy
| | - Andrea Mattiello
- NeuroEpigenetics Laboratory, Department of Cellular, Computational, and Integrative Biology - CIBIO, University of Trento, 38123 Trento, Italy
| | - Dalia Bortolotti
- NeuroEpigenetics Laboratory, Department of Cellular, Computational, and Integrative Biology - CIBIO, University of Trento, 38123 Trento, Italy
| | - Guendalina Bergonzoni
- NeuroEpigenetics Laboratory, Department of Cellular, Computational, and Integrative Biology - CIBIO, University of Trento, 38123 Trento, Italy
| | - Takshashila Tripathi
- NeuroEpigenetics Laboratory, Department of Cellular, Computational, and Integrative Biology - CIBIO, University of Trento, 38123 Trento, Italy
| | - Virginia B Mattis
- Board of Governor's Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Marina Kovalenko
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Jessica Rosati
- Cellular Reprogramming Unit Fondazione IRCCS, Casa Sollievo Della Sofferenza, Viale dei Cappuccini 1, 71013 San Giovanni Rotondo, FG, Italy
| | - Christoph Dieterich
- Section of Bioinformatics and Systems Cardiology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Erik Dassi
- Laboratory of RNA Regulatory Networks, Department of Cellular, Computational, and Integrative Biology - CIBIO, University of Trento, 38123 Trento, Italy
| | - Vanessa C Wheeler
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Zdenka Ellederová
- Research Center PIGMOD, Institute of Animal Physiology and Genetics, Czech Academy of Science, 277 21 Libechov, Czech Republic
| | - Jeremy E Wilusz
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Therapeutic Innovation Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Gabriella Viero
- Institute of Biophysics Unit at Trento, National Research Council - CNR, 38123 Trento, Italy
| | - Marta Biagioli
- NeuroEpigenetics Laboratory, Department of Cellular, Computational, and Integrative Biology - CIBIO, University of Trento, 38123 Trento, Italy
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3
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Mercurio S, Gattoni G, Scarì G, Ascagni M, Barzaghi B, Elphick MR, Croce JC, Schubert M, Benito-Gutiérrez E, Pennati R. A feather star is born: embryonic development and nervous system organization in the crinoid Antedon mediterranea. Open Biol 2024; 14:240115. [PMID: 39165121 PMCID: PMC11336682 DOI: 10.1098/rsob.240115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 06/30/2024] [Accepted: 07/01/2024] [Indexed: 08/22/2024] Open
Abstract
Crinoids belong to the Echinodermata, marine invertebrates with a highly derived adult pentaradial body plan. As the sister group to all other extant echinoderms, crinoids occupy a key phylogenetic position to explore the evolutionary history of the whole phylum. However, their development remains understudied compared with that of other echinoderms. Therefore, the aim here was to establish the Mediterranean feather star (Antedon mediterranea) as an experimental system for developmental biology. We first set up a method for culturing embryos in vitro and defined a standardized staging system for this species. We then optimized protocols to characterize the morphological and molecular development of the main structures of the feather star body plan. Focusing on the nervous system, we showed that the larval apical organ includes serotonergic, GABAergic and glutamatergic neurons, which develop within a conserved anterior molecular signature. We described the composition of the early post-metamorphic nervous system and revealed that it has an anterior signature. These results further our knowledge on crinoid development and provide new techniques to investigate feather star embryogenesis. This will pave the way for the inclusion of crinoids in comparative studies addressing the origin of the echinoderm body plan and the evolutionary diversification of deuterostomes.
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Affiliation(s)
- Silvia Mercurio
- Department of Environmental Science and Policy, Università degli Studi di Milano, Milan, Italy
| | - Giacomo Gattoni
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Giorgio Scarì
- Department of Biosciences, Università degli Studi di Milano, Milan, Italy
| | - Miriam Ascagni
- Unitech NOLIMITS, Università degli Studi di Milano, Milan, Italy
| | - Benedetta Barzaghi
- Department of Environmental Science and Policy, Università degli Studi di Milano, Milan, Italy
| | - Maurice R. Elphick
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Jenifer C. Croce
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Institut de la Mer de Villefranche (IMEV), Sorbonne Université, CNRS, Villefranche-sur-Mer, France
| | - Michael Schubert
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Institut de la Mer de Villefranche (IMEV), Sorbonne Université, CNRS, Villefranche-sur-Mer, France
| | - Elia Benito-Gutiérrez
- Department of Zoology, University of Cambridge, Cambridge, UK
- Department of Neuroscience, Genentech, South San Francisco, CA, USA
| | - Roberta Pennati
- Department of Environmental Science and Policy, Università degli Studi di Milano, Milan, Italy
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4
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Perillo M, Sepe RM, Paganos P, Toscano A, Annunziata R. Sea cucumbers: an emerging system in evo-devo. EvoDevo 2024; 15:3. [PMID: 38368336 PMCID: PMC10874539 DOI: 10.1186/s13227-023-00220-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 12/24/2023] [Indexed: 02/19/2024] Open
Abstract
A challenge for evolutionary developmental (evo-devo) biology is to expand the breadth of research organisms used to investigate how animal diversity has evolved through changes in embryonic development. New experimental systems should couple a relevant phylogenetic position with available molecular tools and genomic resources. As a phylum of the sister group to chordates, echinoderms extensively contributed to our knowledge of embryonic patterning, organ development and cell-type evolution. Echinoderms display a variety of larval forms with diverse shapes, making them a suitable group to compare the evolution of embryonic developmental strategies. However, because of the laboratory accessibility and the already available techniques, most studies focus on sea urchins and sea stars mainly. As a comparative approach, the field would benefit from including information on other members of this group, like the sea cucumbers (holothuroids), for which little is known on the molecular basis of their development. Here, we review the spawning and culture methods, the available morphological and molecular information, and the current state of genomic and transcriptomic resources on sea cucumbers. With the goal of making this system accessible to the broader community, we discuss how sea cucumber embryos and larvae can be a powerful system to address the open questions in evo-devo, including understanding the origins of bilaterian structures.
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Affiliation(s)
- Margherita Perillo
- Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, 7 MBL St., Woods Hole, MA, 02543, USA.
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
| | - Rosa Maria Sepe
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | - Periklis Paganos
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | - Alfonso Toscano
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
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5
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Pagowski V. A description of the bat star nervous system throughout larval ontogeny. Evol Dev 2024; 26:e12468. [PMID: 38108150 DOI: 10.1111/ede.12468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 11/13/2023] [Accepted: 12/05/2023] [Indexed: 12/19/2023]
Abstract
Larvae represent a distinct life history stage in which animal morphology and behavior contrast strongly to adult organisms. This life history stage is a ubiquitous aspect of animal life cycles, particularly in the marine environment. In many species, the structure and function of the nervous system differ significantly between metamorphosed juveniles and larvae. However, the distribution and diversity of neural cell types in larval nervous systems remains incompletely known. Here, the expression of neurotransmitter and neuropeptide synthesis and transport genes in the bat star Patiria miniata is examined throughout larval development. This characterization of nervous system structure reveals three main neural regions with distinct but overlapping territories. These regions include a densely innervated anterior region, an enteric neural plexus, and neurons associated with the ciliary band. In the ciliary band, cholinergic cells are pervasive while dopaminergic, noradrenergic, and GABAergic cells show regional differences in their localization patterns. Furthermore, the distribution of some neural subtypes changes throughout larval development, suggesting that changes in nervous system structure align with shifting ecological priorities during different larval stages, before the development of the adult nervous system. While past work has described aspects of P. miniata larval nervous system structure, largely focusing on early developmental timepoints, this work provides a comprehensive description of neural cell type localization throughout the extensive larval period.
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Affiliation(s)
- Veronica Pagowski
- Hopkins Marine Station of Stanford University, Pacific Grove, California, USA
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6
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Kalachev AV, Tankovich AE. The dopamine effect on sea urchin larvae depends on their age. Dev Growth Differ 2023; 65:120-131. [PMID: 36645274 DOI: 10.1111/dgd.12839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 12/18/2022] [Accepted: 01/10/2023] [Indexed: 01/17/2023]
Abstract
Activation of the dopamine type-D2 receptor in late gastrula of sea urchins is known to decrease the growth rate of post-oral arms of larvae, and, as a result, the phenotype of these larvae mimics that of larvae developing in the abundance of food. Our data indicate that the effect of dopamine on sea urchin larvae is stage-dependent. In our experiment, the early four-armed plutei (96 hours post fertilization, hpf) of Strongylocentrotus intermedius had substantially shorter post-oral arms if they developed from the larvae treated with dopamine at the early pluteus stage (48 hpf), when they had already formed the first dopaminergic neurons, as compared to the plutei from the larvae treated with dopamine at the mid to late gastrula stage (24 hpf), when they did not have any neurons yet. The pre-treatment of larvae in 6-hydroxydopamine, a neurotoxic analog of dopamine that specifically disrupts activity of dopaminergic neurons, prevented the development of the short post-oral arms phenotype in larvae. These results confirm the assumption that dopaminergic neurons play an important role in the development of the short post-oral arms phenotype in sea urchin larvae. Another finding of our study is that the dopamine treatment also affects the growth of the body rods and the overall larval body growth. Based on these observations, we suggest researchers to carefully select the developmental stage, pharmacological agents, and incubation time for experimental manipulation of sea urchin larvae phenotypes through dopaminergic nervous system.
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Affiliation(s)
- Alexander V Kalachev
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok, Russia
| | - Alina E Tankovich
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok, Russia
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7
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Foster S, Oulhen N, Fresques T, Zaki H, Wessel G. Single-cell RNA-sequencing analysis of early sea star development. Development 2022; 149:dev200982. [PMID: 36399063 PMCID: PMC9845752 DOI: 10.1242/dev.200982] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 10/17/2022] [Indexed: 11/21/2022]
Abstract
Echinoderms represent a broad phylum with many tractable features to test evolutionary changes and constraints. Here, we present a single-cell RNA-sequencing analysis of early development in the sea star Patiria miniata, to complement the recent analysis of two sea urchin species. We identified 20 cell states across six developmental stages from 8 hpf to mid-gastrula stage, using the analysis of 25,703 cells. The clusters were assigned cell states based on known marker gene expression and by in situ RNA hybridization. We found that early (morula, 8-14 hpf) and late (blastula-to-mid-gastrula) cell states are transcriptionally distinct. Cells surrounding the blastopore undergo rapid cell state changes that include endomesoderm diversification. Of particular import to understanding germ cell specification is that we never see Nodal pathway members within Nanos/Vasa-positive cells in the region known to give rise to the primordial germ cells (PGCs). The results from this work contrast the results of PGC specification in the sea urchin, and the dataset presented here enables deeper comparative studies in tractable developmental models for testing a variety of developmental mechanisms.
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Affiliation(s)
- Stephany Foster
- Department of Molecular Biology, Cellular Biology & Biochemistry Division of BioMedicine, Brown University,Providence, RI 02912, USA
| | - Nathalie Oulhen
- Department of Molecular Biology, Cellular Biology & Biochemistry Division of BioMedicine, Brown University,Providence, RI 02912, USA
| | - Tara Fresques
- Department of Molecular Biology, Cellular Biology & Biochemistry Division of BioMedicine, Brown University,Providence, RI 02912, USA
| | - Hossam Zaki
- Department of Molecular Biology, Cellular Biology & Biochemistry Division of BioMedicine, Brown University,Providence, RI 02912, USA
| | - Gary Wessel
- Department of Molecular Biology, Cellular Biology & Biochemistry Division of BioMedicine, Brown University,Providence, RI 02912, USA
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8
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Feuda R, Peter IS. Homologous gene regulatory networks control development of apical organs and brains in Bilateria. SCIENCE ADVANCES 2022; 8:eabo2416. [PMID: 36322649 PMCID: PMC9629743 DOI: 10.1126/sciadv.abo2416] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Apical organs are relatively simple larval nervous systems. The extent to which apical organs are evolutionarily related to the more complex nervous systems of other animals remains unclear. To identify common developmental mechanisms, we analyzed the gene regulatory network (GRN) controlling the development of the apical organ in sea urchins. We characterized the developmental expression of 30 transcription factors and identified key regulatory functions for FoxQ2, Hbn, Delta/Notch signaling, and SoxC in the patterning of the apical organ and the specification of neurons. Almost the entire set of apical transcription factors is expressed in the nervous system of worms, flies, zebrafish, frogs, and mice. Furthermore, a regulatory module controlling the axial patterning of the vertebrate brain is expressed in the ectoderm of sea urchin embryos. We conclude that GRNs controlling the formation of bilaterian nervous systems share a common origin and that the apical GRN likely resembles an ancestral regulatory program.
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Zheng Y, Cong X, Liu H, Wang Y, Storey KB, Chen M. Nervous System Development and Neuropeptides Characterization in Embryo and Larva: Insights from a Non-Chordate Deuterostome, the Sea Cucumber Apostichopus japonicus. BIOLOGY 2022; 11:biology11101538. [PMID: 36290441 PMCID: PMC9598280 DOI: 10.3390/biology11101538] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 10/17/2022] [Accepted: 10/18/2022] [Indexed: 11/16/2022]
Abstract
Here, we described the complex nervous system at five early developmental stages (blastula, gastrula, auricularia, doliolaria and pentactula) of a holothurian species with highly economic value, Apostichopus japonicus. The results revealed that the nervous system of embryos and larvae is mainly distributed in the anterior apical region, ciliary bands or rings, and the feeding and attachment organs, and that serotonergic immunoreactivity was not observed until the embryo developed into the late gastrula; these are evolutionarily conserved features of echinoderm, hemichordate and protostome larvae. Furthermore, based on available transcriptome data, we reported the neuropeptide precursors profile at different embryonic and larval developmental stages. This analysis showed that 40 neuropeptide precursors present in adult sea cucumbers were also identified at different developmental stages of embryos and larvae, and only four neuropeptide precursors (SWYG precursor 2, GYWKDLDNYVKAHKT precursor, Neuropeptide precursor 14-like precursor, GLRFAmprecursor-like precursor) predicted in adults were absent in embryos and larvae. Combining the quantitative expression of ten specific neuropeptide precursor genes (NPs) by qRT-PCR, we revealed the potential important roles of neuropeptides in embryo development, feeding and attachment in A. japonicus larvae. In conclusion, this work provides novel perspectives on the diverse physiological functions of neuropeptides and contributes to understanding the evolution of neuropeptidergic systems in echinoderm embryos and larvae.
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Affiliation(s)
- Yingqiu Zheng
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Xiao Cong
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Huachen Liu
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Yixin Wang
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
| | - Kenneth B. Storey
- Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
| | - Muyan Chen
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China
- Correspondence:
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10
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Barone V, Lyons DC. Live imaging of echinoderm embryos to illuminate evo-devo. Front Cell Dev Biol 2022; 10:1007775. [PMID: 36187474 PMCID: PMC9521734 DOI: 10.3389/fcell.2022.1007775] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 08/24/2022] [Indexed: 11/16/2022] Open
Abstract
Echinoderm embryos have been model systems for cell and developmental biology for over 150 years, in good part because of their optical clarity. Discoveries that shaped our understanding of fertilization, cell division and cell differentiation were only possible because of the transparency of sea urchin eggs and embryos, which allowed direct observations of intracellular structures. More recently, live imaging of sea urchin embryos, coupled with fluorescence microscopy, has proven pivotal to uncovering mechanisms of epithelial to mesenchymal transition, cell migration and gastrulation. However, live imaging has mainly been performed on sea urchin embryos, while echinoderms include numerous experimentally tractable species that present interesting variation in key aspects of morphogenesis, including differences in embryo compaction and mechanisms of blastula formation. The study of such variation would allow us not only to understand how tissues are formed in echinoderms, but also to identify which changes in cell shape, cell-matrix and cell-cell contact formation are more likely to result in evolution of new embryonic shapes. Here we argue that adapting live imaging techniques to more echinoderm species will be fundamental to exploit such an evolutionary approach to the study of morphogenesis, as it will allow measuring differences in dynamic cellular behaviors - such as changes in cell shape and cell adhesion - between species. We briefly review existing methods for live imaging of echinoderm embryos and describe in detail how we adapted those methods to allow long-term live imaging of several species, namely the sea urchin Lytechinus pictus and the sea stars Patiria miniata and Patiriella regularis. We outline procedures to successfully label, mount and image early embryos for 10–16 h, from cleavage stages to early blastula. We show that data obtained with these methods allows 3D segmentation and tracking of individual cells over time, the first step to analyze how cell shape and cell contact differ among species. The methods presented here can be easily adopted by most cell and developmental biology laboratories and adapted to successfully image early embryos of additional species, therefore broadening our understanding of the evolution of morphogenesis.
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11
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Lineage tracing shows that cell size asymmetries predict the dorsoventral axis in the sea star embryo. BMC Biol 2022; 20:179. [PMID: 35971116 PMCID: PMC9380389 DOI: 10.1186/s12915-022-01359-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 06/23/2022] [Indexed: 11/21/2022] Open
Abstract
Background Cell size asymmetries are often linked to cell fate decisions, due to cell volumes and cell fate determinants being unequally partitioned during asymmetric cell divisions. A clear example is found in the sea urchin embryo, where a characteristic and obvious unequal 4th cleavage generates micromeres, which are necessary for mesendoderm cell fate specification. Unlike sea urchin development, sea star development is generally thought to have only equal cleavage. However, subtle cell size asymmetries can be observed in sea star embryos; whether those cell size asymmetries are consistently produced during sea star development and if they are involved in cell fate decisions remains unknown. Results Using confocal live imaging of early embryos we quantified cell size asymmetries in 16-cell stage embryos of two sea star species, Patiria miniata and Patiriella regularis. Using photoconversion to perform lineage tracing, we find that the position of the smallest cells of P. miniata embryos is biased toward anterior ventral tissues. However, both blastomere dissociation and mechanical removal of one small cell do not prevent dorsoventral (DV) axis formation, suggesting that embryos compensate for the loss of those cells and that asymmetrical partitioning of maternal determinants is not strictly necessary for DV patterning. Finally, we show that manipulating cell size to introduce artificial cell size asymmetries is not sufficient to direct the positioning of the future DV axis in P. miniata embryos. Conclusions Our results show that although cell size asymmetries are consistently produced during sea star early cleavage and are predictive of the DV axis, they are not necessary to instruct DV axis formation. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01359-3.
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12
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Bonaventura R, Costa C, Deidda I, Zito F, Russo R. Gene Expression Analysis of the Stress Response to Lithium, Nickel, and Zinc in Paracentrotus lividus Embryos. TOXICS 2022; 10:toxics10060325. [PMID: 35736933 PMCID: PMC9231221 DOI: 10.3390/toxics10060325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 06/06/2022] [Accepted: 06/11/2022] [Indexed: 02/04/2023]
Abstract
Many anthropogenic pollutants such as metals are discharged into the marine environment through modern sources. Among these, lithium (Li), nickel (Ni), and zinc (Zn) can interfere with biological processes in many organisms when their concentration rises. These metals are toxic to sea urchin embryos, affecting their development. Indeed, animal/vegetal and dorso/ventral embryonic axes are differently perturbed: Li is a vegetalizing agent, Ni can disrupt dorso-ventral axis, Zn can be animalizing. To address the molecular response adopted by embryos to cope with these metals or involved in the gene networks regulating embryogenesis, and to detect new biomarkers for evaluating hazards in polluted environments in a well-known in vivo model, we applied a high-throughput screening approach to sea urchin embryos. After fertilization, Paracentrotus lividus embryos were exposed to Li, Ni, and Zn for 24/48 h. At both endpoints, RNAs were analyzed by NanoString nCounter technology. By in silico analyses, we selected a panel of 127 transcripts encoding for regulatory and structural proteins, ranked in categories: Apoptosis, Defense, Immune, Nervous, Development, and Biomineralization. The data analysis highlighted the dysregulation of many genes in a metal-dependent manner. A functional annotation analysis was performed by the KEEG Orthology database. This study provides a platform for research on metals biomarkers in sea urchins.
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13
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A subterminal growth zone at arm tip likely underlies life-long indeterminate growth in brittle stars. Front Zool 2022; 19:15. [PMID: 35413857 PMCID: PMC9004015 DOI: 10.1186/s12983-022-00461-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 04/03/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Echinoderms are a phylum of marine invertebrates with close phylogenetic relationships to chordates. Many members of the phylum Echinodermata are capable of extensive post-traumatic regeneration and life-long indeterminate growth. Different from regeneration, the life-long elongation of the main body axis in adult echinoderms has received little attention. The anatomical location and the nature of the dividing progenitor cells contributing to adults' growth is unknown. RESULTS We show that the proliferating cells that drive the life-long growth of adult brittle star arms are mostly localized to the subterminal (second from the tip) arm segment. Each of the major anatomical structures contains dividing progenitors. These structures include: the radial nerve, water-vascular canal, and arm coelomic wall. Some of those proliferating progenitor cells are capable of multiple rounds of cell division. Within the nervous system, the progenitor cells were identified as a subset of radial glial cells that do not express Brn1/2/4, a transcription factor with a conserved role in the neuronal fate specification. In addition to characterizing the growth zone and the nature of the precursor cells, we provide a description of the microanatomy of the four distal-most arm segments contrasting the distal with the proximal segments, which are more mature. CONCLUSIONS The growth of the adult brittle star arms occurs via proliferation of progenitor cells in the distal segments, which are most abundant in the second segment from the tip. At least some of the progenitors are capable of multiple rounds of cell division. Within the nervous system the dividing cells were identified as Brn1/2/4-negative radial glial cells.
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14
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The evolutionary history of the polyQ tract in huntingtin sheds light on its functional pro-neural activities. Cell Death Differ 2022; 29:293-305. [PMID: 34974533 PMCID: PMC8817008 DOI: 10.1038/s41418-021-00914-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 11/09/2021] [Accepted: 11/24/2021] [Indexed: 12/15/2022] Open
Abstract
Huntington's disease is caused by a pathologically long (>35) CAG repeat located in the first exon of the Huntingtin gene (HTT). While pathologically expanded CAG repeats are the focus of extensive investigations, non-pathogenic CAG tracts in protein-coding genes are less well characterized. Here, we investigated the function and evolution of the physiological CAG tract in the HTT gene. We show that the poly-glutamine (polyQ) tract encoded by CAGs in the huntingtin protein (HTT) is under purifying selection and subjected to stronger selective pressures than CAG-encoded polyQ tracts in other proteins. For natural selection to operate, the polyQ must perform a function. By combining genome-edited mouse embryonic stem cells and cell assays, we show that small variations in HTT polyQ lengths significantly correlate with cells' neurogenic potential and with changes in the gene transcription network governing neuronal function. We conclude that during evolution natural selection promotes the conservation and purity of the CAG-encoded polyQ tract and that small increases in its physiological length influence neural functions of HTT. We propose that these changes in HTT polyQ length contribute to evolutionary fitness including potentially to the development of a more complex nervous system.
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15
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Zheng M, Zueva O, Hinman V. Regeneration of the larval sea star nervous system by wounding induced respecification to the sox2 lineage. eLife 2022; 11:72983. [PMID: 35029145 PMCID: PMC8809897 DOI: 10.7554/elife.72983] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 01/13/2022] [Indexed: 11/20/2022] Open
Abstract
The ability to restore lost body parts following traumatic injury is a fascinating area of biology that challenges current understanding of the ontogeny of differentiation. The origin of new cells needed to regenerate lost tissue, and whether they are pluripotent or have de- or trans-differentiated, remains one of the most important open questions . Additionally, it is not known whether developmental gene regulatory networks are reused or whether regeneration specific networks are deployed. Echinoderms, including sea stars, have extensive ability for regeneration, however, the technologies for obtaining transgenic echinoderms are limited and tracking cells involved in regeneration, and thus identifying the cellular sources and potencies has proven challenging. In this study, we develop new transgenic tools to follow the fate of populations of cells in the regenerating larva of the sea star Patiria miniata. We show that the larval serotonergic nervous system can regenerate following decapitation. Using a BAC-transgenesis approach we show that expression of the pan ectodermal marker, sox2, is induced in previously sox2 minus cells , even when cell division is inhibited. sox2+ cells give rise to new sox4+ neural precursors that then proceed along an embryonic neurogenesis pathway to reform the anterior nervous systems. sox2+ cells contribute to only neural and ectoderm lineages, indicating that these progenitors maintain their normal, embryonic lineage restriction. This indicates that sea star larval regeneration uses a combination of existing lineage restricted stem cells, as well as respecification of cells into neural lineages, and at least partial reuse of developmental GRNs to regenerate their nervous system.
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Affiliation(s)
- Minyan Zheng
- Department of Genetics, Harvard Medical School, Boston, United States
| | - Olga Zueva
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, United States
| | - Veronica Hinman
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, United States
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16
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Carter HF, Thompson JR, Elphick MR, Oliveri P. The Development and Neuronal Complexity of Bipinnaria Larvae of the Sea Star Asterias rubens. Integr Comp Biol 2021; 61:337-351. [PMID: 34048552 PMCID: PMC8427176 DOI: 10.1093/icb/icab103] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Free-swimming planktonic larvae are a key stage in the development of many marine phyla, and studies of these organisms have contributed to our understanding of major genetic and evolutionary processes. Although transitory, these larvae often attain a remarkable degree of tissue complexity, with well-defined musculature and nervous systems. Among the best studied are larvae belonging to the phylum Echinodermata, but with work largely focused on the pluteus larvae of sea urchins (class Echinoidea). The greatest diversity of larval strategies among echinoderms is found in the class Asteroidea (sea stars), organisms that are rapidly emerging as experimental systems for genetic and developmental studies. However, the bipinnaria larvae of sea stars have only been studied in detail in a small number of species and although they have been relatively well described neuro-anatomically, they are poorly understood neurochemically. Here, we have analyzed embryonic development and bipinnaria larval anatomy in the common North Atlantic sea star Asterias rubens, using a variety of staining methods in combination with confocal microscopy. Importantly, the chemical complexity of the nervous system of bipinnaria larvae was revealed through use of a diverse set of antibodies, with identification of at least three centers of differing neurochemical signature within the previously described nervous system: the anterior apical organ, oral region, and ciliary bands. Furthermore, the anatomy of the musculature and sites of cell division in bipinnaria larvae was analyzed. Comparisons of developmental progression and molecular anatomy across the Echinodermata provided a basis for hypotheses on the shared evolutionary and developmental processes that have shaped this group of animals. We conclude that bipinnaria larvae appear to be remarkably conserved across ∼200 million years of evolutionary time and may represent a strong evolutionary and/or developmental constraint on species utilizing this larval strategy.
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Affiliation(s)
- Hugh F Carter
- Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
- Department of Life Sciences, Natural History Museum, Cromwell Road, South Kensington, London SW7 5BD, UK
| | - Jeffrey R Thompson
- Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
- UCL Centre for Life’s Origins and Evolution (CLOE), University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Maurice R Elphick
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Paola Oliveri
- Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
- UCL Centre for Life’s Origins and Evolution (CLOE), University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
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17
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Bronchain O, Philippe-Caraty L, Anquetil V, Ciapa B. Precise regulation of presenilin expression is required for sea urchin early development. J Cell Sci 2021; 134:jcs258382. [PMID: 34313316 DOI: 10.1242/jcs.258382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 05/24/2021] [Indexed: 11/20/2022] Open
Abstract
Presenilins (PSENs) are widely expressed across eukaryotes. Two PSENs are expressed in humans, where they play a crucial role in Alzheimer's disease (AD). Each PSEN can be part of the γ-secretase complex, which has multiple substrates, including Notch and amyloid-β precursor protein (AβPP) - the source of amyloid-β (Aβ) peptides that compose the senile plaques during AD. PSENs also interact with various proteins independently of their γ-secretase activity. They can then be involved in numerous cellular functions, which makes their role in a given cell and/or organism complex to decipher. We have established the Paracentrotus lividus sea urchin embryo as a new model to study the role of PSEN. In the sea urchin embryo, the PSEN gene is present in unduplicated form and encodes a protein highly similar to human PSENs. Our results suggest that PSEN expression must be precisely tuned to control the course of the first mitotic cycles and the associated intracellular Ca2+ transients, the execution of gastrulation and, probably in association with ciliated cells, the establishment of the pluteus. We suggest that it would be relevant to study the role of PSEN within the gene regulatory network deciphered in the sea urchin.
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Affiliation(s)
- Odile Bronchain
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| | - Laetitia Philippe-Caraty
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| | - Vincent Anquetil
- Sorbonne Université, Inserm U1127, CNRS UMR 7225, Institut du Cerveau (ICM), F-75013, Paris, France
| | - Brigitte Ciapa
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
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18
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Byrne M, Koop D, Strbenac D, Cisternas P, Balogh R, Yang JYH, Davidson PL, Wray G. Transcriptomic analysis of sea star development through metamorphosis to the highly derived pentameral body plan with a focus on neural transcription factors. DNA Res 2021; 27:5825731. [PMID: 32339242 PMCID: PMC7315356 DOI: 10.1093/dnares/dsaa007] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 04/20/2020] [Indexed: 12/13/2022] Open
Abstract
The Echinodermata is characterized by a secondarily evolved pentameral body plan. While the evolutionary origin of this body plan has been the subject of debate, the molecular mechanisms underlying its development are poorly understood. We assembled a de novo developmental transcriptome from the embryo through metamorphosis in the sea star Parvulastra exigua. We use the asteroid model as it represents the basal-type echinoderm body architecture. Global variation in gene expression distinguished the gastrula profile and showed that metamorphic and juvenile stages were more similar to each other than to the pre-metamorphic stages, pointing to the marked changes that occur during metamorphosis. Differential expression and gene ontology (GO) analyses revealed dynamic changes in gene expression throughout development and the transition to pentamery. Many GO terms enriched during late metamorphosis were related to neurogenesis and signalling. Neural transcription factor genes exhibited clusters with distinct expression patterns. A suite of these genes was up-regulated during metamorphosis (e.g. Pax6, Eya, Hey, NeuroD, FoxD, Mbx, and Otp). In situ hybridization showed expression of neural genes in the CNS and sensory structures. Our results provide a foundation to understand the metamorphic transition in echinoderms and the genes involved in development and evolution of pentamery.
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Affiliation(s)
- Maria Byrne
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Demian Koop
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Dario Strbenac
- School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006, Australia
| | - Paula Cisternas
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Regina Balogh
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Jean Yee Hwa Yang
- School of Mathematics and Statistics, The University of Sydney, Sydney, NSW 2006, Australia
| | | | - Gregory Wray
- Department of Biology, Duke University, Durham, NC 27708, USA.,Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
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19
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Bonaventura R, Zito F, Russo R, Costa C. A preliminary gene expression analysis on Paracentrotus lividus embryos exposed to UVB, Cadmium and their combination. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2021; 232:105770. [PMID: 33581547 DOI: 10.1016/j.aquatox.2021.105770] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 01/18/2021] [Accepted: 01/27/2021] [Indexed: 06/12/2023]
Abstract
Paracentrotus lividus is a Mediterranean and Eastern Atlantic sea urchin species, very sensitive to chemical and physical environmental changes and widely used in eco-toxicological studies. Here, we applied a high throughput screening approach on P. lividus embryos exposed to UVB radiation (UV), Cadmium Chloride (Cd) and their combination (Cd/UV), to deeply characterize the molecular responses adopted by embryos to cope with these stressors. in vitro eco-toxicological assays were performed by exposing embryos to Cd (10-4 M) soon after fertilization, to UV (200 and 400J/m2) at early stage of development, while in co-exposure experiments, Cd-exposed embryos were irradiated with UV at 200 J/m2. By NanoString nCounter technology, custom-made probes were developed and hybridized on total RNA extracted from exposed embryos at 51h after fertilization. By in silico analyses, we selected and retrieved at the NCBI nucleotide database a panel of P. lividus transcripts encoding for many regulatory and structural proteins that we ranked in categories, i.e., Apoptosis, Biomineralization, Defense, Development, Immunity, Signaling and Transcription Factors. The analysis of 127 transcripts highlighted the dysregulation of many genes, some specifically activated to cope with stress agents, others involved in the complex molecular network of genes that regulate embryo development. We revealed the downregulation of Biomineralization and Development genes and the upregulation of Defensive genes in Cd and Cd/UV embryos. Our approach, using sea urchin embryo as an in vivomodel, contributes to advance our knowledge about cellular responses to UV, Cd and their combination.
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Affiliation(s)
- Rosa Bonaventura
- Consiglio Nazionale delle Ricerche, Istituto per la Ricerca e l'Innovazione Biomedica, Via Ugo La Malfa 153, Palermo, 90146, Italy.
| | - Francesca Zito
- Consiglio Nazionale delle Ricerche, Istituto per la Ricerca e l'Innovazione Biomedica, Via Ugo La Malfa 153, Palermo, 90146, Italy
| | - Roberta Russo
- Consiglio Nazionale delle Ricerche, Istituto per la Ricerca e l'Innovazione Biomedica, Via Ugo La Malfa 153, Palermo, 90146, Italy.
| | - Caterina Costa
- Consiglio Nazionale delle Ricerche, Istituto per la Ricerca e l'Innovazione Biomedica, Via Ugo La Malfa 153, Palermo, 90146, Italy
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20
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Formery L, Orange F, Formery A, Yaguchi S, Lowe CJ, Schubert M, Croce JC. Neural anatomy of echinoid early juveniles and comparison of nervous system organization in echinoderms. J Comp Neurol 2020; 529:1135-1156. [PMID: 32841380 DOI: 10.1002/cne.25012] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/07/2020] [Accepted: 07/24/2020] [Indexed: 12/12/2022]
Abstract
The echinoderms are a phylum of marine deuterostomes characterized by the pentaradial (five fold) symmetry of their adult bodies. Due to this unusual body plan, adult echinoderms have long been excluded from comparative analyses aimed at understanding the origin and evolution of deuterostome nervous systems. Here, we investigated the neural anatomy of early juveniles of representatives of three of the five echinoderm classes: the echinoid Paracentrotus lividus, the asteroid Patiria miniata, and the holothuroid Parastichopus parvimensis. Using whole mount immunohistochemistry and confocal microscopy, we found that the nervous system of echinoid early juveniles is composed of three main structures: a basiepidermal nerve plexus, five radial nerve cords connected by a circumoral nerve ring, and peripheral nerves innervating the appendages. Our whole mount preparations further allowed us to obtain thorough descriptions of these structures and of several innervation patterns, in particular at the level of the appendages. Detailed comparisons of the echinoid juvenile nervous system with those of asteroid and holothuroid juveniles moreover supported a general conservation of the main neural structures in all three species, including at the level of the appendages. Our results support the previously proposed hypotheses for the existence of two neural units in echinoderms: one consisting of the basiepidermal nerve plexus to process sensory stimuli locally and one composed of the radial nerve cords and the peripheral nerves constituting a centralized control system. This study provides the basis for more in-depth comparisons of the echinoderm adult nervous system with those of other animals, in particular hemichordates and chordates, to address the long-standing controversies about deuterostome nervous system evolution.
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Affiliation(s)
- Laurent Formery
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Evolution of Intracellular Signaling in Development (EvoInSiDe), Sorbonne Université, CNRS, Villefranche-sur-Mer, France
| | - François Orange
- Centre Commun de Microscopie Appliquée (CCMA), Université Côte d'Azur, Nice, France
| | | | - Shunsuke Yaguchi
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
| | - Christopher J Lowe
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, California, USA
| | - Michael Schubert
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Evolution of Intracellular Signaling in Development (EvoInSiDe), Sorbonne Université, CNRS, Villefranche-sur-Mer, France
| | - Jenifer C Croce
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Evolution of Intracellular Signaling in Development (EvoInSiDe), Sorbonne Université, CNRS, Villefranche-sur-Mer, France
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21
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Kumar S, Tumu SC, Helm C, Hausen H. The development of early pioneer neurons in the annelid Malacoceros fuliginosus. BMC Evol Biol 2020; 20:117. [PMID: 32928118 PMCID: PMC7489019 DOI: 10.1186/s12862-020-01680-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 08/27/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Nervous system development is an interplay of many processes: the formation of individual neurons, which depends on whole-body and local patterning processes, and the coordinated growth of neurites and synapse formation. While knowledge of neural patterning in several animal groups is increasing, data on pioneer neurons that create the early axonal scaffold are scarce. Here we studied the first steps of nervous system development in the annelid Malacoceros fuliginosus. RESULTS We performed a dense expression profiling of a broad set of neural genes. We found that SoxB expression begins at 4 h postfertilization, and shortly later, the neuronal progenitors can be identified at the anterior and the posterior pole by the transient and dynamic expression of proneural genes. At 9 hpf, the first neuronal cells start differentiating, and we provide a detailed description of axonal outgrowth of the pioneer neurons that create the primary neuronal scaffold. Tracing back the clonal origin of the ventral nerve cord pioneer neuron revealed that it is a descendant of the blastomere 2d (2d221), which after 7 cleavages starts expressing Neurogenin, Acheate-Scute and NeuroD. CONCLUSIONS We propose that an anterior and posterior origin of the nervous system is ancestral in annelids. We suggest that closer examination of the first pioneer neurons will be valuable in better understanding of nervous system development in spirally cleaving animals, to determine the potential role of cell-intrinsic properties in neuronal specification and to resolve the evolution of nervous systems.
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Affiliation(s)
- Suman Kumar
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Sharat Chandra Tumu
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Conrad Helm
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.,Present Address: Johann-Friedrich-Blumenbach Institute for Zoology and Anthropology, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Harald Hausen
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.
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22
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Ming H, Sun J, Pasquariello R, Gatenby L, Herrick JR, Yuan Y, Pinto CR, Bondioli KR, Krisher RL, Jiang Z. The landscape of accessible chromatin in bovine oocytes and early embryos. Epigenetics 2020; 16:300-312. [PMID: 32663104 DOI: 10.1080/15592294.2020.1795602] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Chromatin reorganization governs the regulation of gene expression during preimplantation development. However, the landscape of chromatin dynamics in this period has not been explored in bovine. In this study, we constructed a genome-wide map of accessible chromatin in bovine oocytes and early embryos using an improved assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) which revealed unique features of the accessible chromatin during bovine early embryo development. We found that chromatin accessibility is low in oocytes and 2-/4-cell embryos, followed by a significant increase in embryos during major embryonic genome activation (EGA), and peaked in elongating day 14 embryos. Genome-wide characteristics of open chromatin showed that ATAC-seq signals in both transcription start sites (TSS) and transcription end sites (TES) were strong. Additionally, the distal ATAC-seq peaks were enriched in repeat elements in a type-specific and stage-specific manner. We further unveiled a series of transcription factor (TF) motifs with distinct variation of enrichment from distal ATAC-seq peaks. By integrated analysis of chromatin accessibility with transcriptomes and DNA methylomes in bovine early embryos, we showed that promoter accessibility was positively correlated with gene expression, especially during major EGA, and was strongly correlated to DNA methylation and CpG density. Finally, we identified the critical chromatin signatures and TFs that differ between in vivo and in vitro derived blastocysts, which provides insights to the potential mechanisms leading to low quality of embryos produced in vitro. Together, this comprehensive analysis revealed critical features of chromatin landscape and epigenetic reprogramming during bovine preimplantation embryo development.
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Affiliation(s)
- Hao Ming
- School of Animal Sciences, AgCenter, Louisiana State University , Baton Rouge, LA, USA
| | - Jiangwen Sun
- Department of Computer Science, Old Dominion University , Norfolk, VA, USA
| | | | - Lauren Gatenby
- School of Animal Sciences, AgCenter, Louisiana State University , Baton Rouge, LA, USA
| | - Jason R Herrick
- Colorado Center for Reproductive Medicine , Lone Tree, CO, USA
| | - Ye Yuan
- Colorado Center for Reproductive Medicine , Lone Tree, CO, USA
| | - Carlos R Pinto
- Department of Theriogenology, School of Veterinary Medicine, Louisiana State University , Baton Rouge, LA, USA
| | - Kenneth R Bondioli
- School of Animal Sciences, AgCenter, Louisiana State University , Baton Rouge, LA, USA
| | | | - Zongliang Jiang
- School of Animal Sciences, AgCenter, Louisiana State University , Baton Rouge, LA, USA
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23
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Mashanov V, Akiona J, Khoury M, Ferrier J, Reid R, Machado DJ, Zueva O, Janies D. Active Notch signaling is required for arm regeneration in a brittle star. PLoS One 2020; 15:e0232981. [PMID: 32396580 PMCID: PMC7217437 DOI: 10.1371/journal.pone.0232981] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 04/24/2020] [Indexed: 12/15/2022] Open
Abstract
Cell signaling pathways play key roles in coordinating cellular events in development. The Notch signaling pathway is highly conserved across all multicellular animals and is known to coordinate a multitude of diverse cellular events, including proliferation, differentiation, fate specification, and cell death. Specific functions of the pathway are, however, highly context-dependent and are not well characterized in post-traumatic regeneration. Here, we use a small-molecule inhibitor of the pathway (DAPT) to demonstrate that Notch signaling is required for proper arm regeneration in the brittle star Ophioderma brevispina, a highly regenerative member of the phylum Echinodermata. We also employ a transcriptome-wide gene expression analysis (RNA-seq) to characterize the downstream genes controlled by the Notch pathway in the brittle star regeneration. We demonstrate that arm regeneration involves an extensive cross-talk between the Notch pathway and other cell signaling pathways. In the regrowing arm, Notch regulates the composition of the extracellular matrix, cell migration, proliferation, and apoptosis, as well as components of the innate immune response. We also show for the first time that Notch signaling regulates the activity of several transposable elements. Our data also suggests that one of the possible mechanisms through which Notch sustains its activity in the regenerating tissues is via suppression of Neuralized1.
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Affiliation(s)
- Vladimir Mashanov
- Department of Biology, University of North Florida, Jacksonville, FL, United states of America
- Wake Forest Institute for Regenerative Medicine, Winston Salem, NC, United states of America
- * E-mail:
| | - Jennifer Akiona
- Department of Biology, University of North Florida, Jacksonville, FL, United states of America
| | - Maleana Khoury
- Department of Biology, University of North Florida, Jacksonville, FL, United states of America
| | - Jacob Ferrier
- University of North Carolina at Charlotte, Charlotte, NC, United states of America
| | - Robert Reid
- University of North Carolina at Charlotte, Charlotte, NC, United states of America
| | - Denis Jacob Machado
- University of North Carolina at Charlotte, Charlotte, NC, United states of America
| | - Olga Zueva
- Department of Biology, University of North Florida, Jacksonville, FL, United states of America
| | - Daniel Janies
- University of North Carolina at Charlotte, Charlotte, NC, United states of America
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Slota LA, Miranda E, Peskin B, McClay DR. Developmental origin of peripheral ciliary band neurons in the sea urchin embryo. Dev Biol 2020; 459:72-78. [PMID: 31881199 PMCID: PMC7080585 DOI: 10.1016/j.ydbio.2019.12.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 12/17/2019] [Accepted: 12/20/2019] [Indexed: 10/25/2022]
Abstract
In the sea urchin larva, most neurons lie within an ectodermal region called the ciliary band. Our understanding of the mechanisms of specification and patterning of these peripheral ciliary band neurons is incomplete. Here, we first examine the gene regulatory landscape from which this population of neural progenitors arise in the neuroectoderm. We show that ciliary band neural progenitors first appear in a bilaterally symmetric pattern on the lateral edges of chordin expression in the neuroectoderm. Later in development, these progenitors appear in a salt-and-pepper pattern in the ciliary band where they express soxC, and prox, which are markers of neural specification, and begin to express synaptotagminB, a marker of differentiated neurons. We show that the ciliary band expresses the acid sensing ion channel gene asicl, which suggests that ciliary band neurons control the larva's ability to discern touch sensitivity. Using a chemical inhibitor of MAPK signaling, we show that this signaling pathway is required for proper specification and patterning of ciliary band neurons. Using live imaging, we show that these neural progenitors undergo small distance migrations in the embryo. We then show that the normal swimming behavior of the larvae is compromised if the neurogenesis pathway is perturbed. The developmental sequence of ciliary band neurons is very similar to that of neural crest-derived sensory neurons in vertebrates and may provide insights into the evolution of sensory neurons in deuterostomes.
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Affiliation(s)
- Leslie A Slota
- Department of Biology, Duke University, Durham, NC, 27708, USA
| | - Esther Miranda
- Department of Biology, Duke University, Durham, NC, 27708, USA
| | - Brianna Peskin
- Department of Biology, Duke University, Durham, NC, 27708, USA
| | - David R McClay
- Department of Biology, Duke University, Durham, NC, 27708, USA.
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Ortega A, Olivares-Bañuelos TN. Neurons and Glia Cells in Marine Invertebrates: An Update. Front Neurosci 2020; 14:121. [PMID: 32132895 PMCID: PMC7040184 DOI: 10.3389/fnins.2020.00121] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 01/30/2020] [Indexed: 12/18/2022] Open
Abstract
The nervous system (NS) of invertebrates and vertebrates is composed of two main types of cells: neurons and glia. In both types of organisms, nerve cells have similarities in biochemistry and functionality. The neurons are in charge of the synapse, and the glial cells are in charge of important functions of neuronal and homeostatic modulation. Knowing the mechanisms by which NS cells work is important in the biomedical area for the diagnosis and treatment of neurological disorders. For this reason, cellular and animal models to study the properties and characteristics of the NS are always sought. Marine invertebrates are strategic study models for the biological sciences. The sea slug Aplysia californica and the squid Loligo pealei are two examples of marine key organisms in the neurosciences field. The principal characteristic of marine invertebrates is that they have a simpler NS that consists of few and larger cells, which are well organized and have accessible structures. As well, the close phylogenetic relationship between Chordata and Echinodermata constitutes an additional advantage to use these organisms as a model for the functionality of neuronal cells and their cellular plasticity. Currently, there is great interest in analyzing the signaling processes between neurons and glial cells, both in vertebrates and in invertebrates. However, only few types of glial cells of invertebrates, mostly insects, have been studied, and it is important to consider marine organisms' research. For this reason, the objective of the review is to present an update of the most relevant information that exists around the physiology of marine invertebrate neuronal and glial cells.
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Affiliation(s)
- Arturo Ortega
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
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García-Arrarás JE, Lefebre-Rivera M, Qi-Huang S. Enteroendocrine cells in the Echinodermata. Cell Tissue Res 2019; 377:459-467. [PMID: 31222501 DOI: 10.1007/s00441-019-03053-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 05/24/2019] [Indexed: 12/24/2022]
Abstract
Enteroendocrine cells are endocrine-like cells found in the luminal epithelia of the digestive tract. These cells have been described in most animal phyla. In echinoderms, the cells have been described mainly in organisms of the class Asteroidea (sea stars) and Holothuroidea (sea cucumbers). Here, we describe what is known about the enteroendocrine cells of the Echinodermata, including the cell types, their distribution in the digestive tract, their neuropeptide content and their regeneration and compare them to what has been found in other animal species, mainly in vertebrates. We also discuss the newly described view of enteroendocrine cells as chemical sensors of the intestinal lumen and provide some histological evidence that similar functions might be found within the echinoderms. Finally, we describe the temporal regeneration of the enteroendocrine cells in the holothurian intestine.
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Slota LA, Miranda EM, McClay DR. Spatial and temporal patterns of gene expression during neurogenesis in the sea urchin Lytechinus variegatus. EvoDevo 2019; 10:2. [PMID: 30792836 PMCID: PMC6371548 DOI: 10.1186/s13227-019-0115-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 01/30/2019] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The sea urchin is a basal deuterostome that is more closely related to vertebrates than many organisms traditionally used to study neurogenesis. This phylogenetic position means that the sea urchin can provide insights into the evolution of the nervous system by helping resolve which developmental processes are deuterostome innovations, which are innovations in other clades, and which are ancestral. However, the nervous system of echinoderms is one of the least understood of all major metazoan phyla. To gain insights into echinoderm neurogenesis, spatial and temporal gene expression data are essential. Then, functional data will enable the building of a detailed gene regulatory network for neurogenesis in the sea urchin that can be compared across metazoans to resolve questions about how nervous systems evolved. RESULTS Here, we analyze spatiotemporal gene expression during sea urchin neurogenesis for genes that have been shown to be neurogenic in one or more species. We report the expression of 21 genes expressed in areas of neurogenesis in the sea urchin embryo from blastula stage (just before neural progenitors begin their specification sequence) through pluteus larval stage (when much of the nervous system has been patterned). Among those 21 gene expression patterns, we report expression of 11 transcription factors and 2 axon guidance genes, each expressed in discrete domains in the neuroectoderm or in the endoderm. Most of these genes are expressed in and around the ciliary band. Some including the transcription factors Lv-mbx, Lv-dmrt, Lv-islet, and Lv-atbf1, the nuclear protein Lv-prohibitin, and the guidance molecule Lv-semaa are expressed in the endoderm where they are presumably involved in neurogenesis in the gut. CONCLUSIONS This study builds a foundation to study how neurons are specified and evolved by analyzing spatial and temporal gene expression during neurogenesis in a basal deuterostome. With these expression patterns, we will be able to understand what genes are required for neural development in the sea urchin. These data can be used as a starting point to (1) build a spatial gene regulatory network for sea urchin neurogenesis, (2) identify how subtypes of neurons are specified, (3) perform comparative studies with the sea urchin, protostome, and vertebrate organisms.
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Affiliation(s)
- Leslie A. Slota
- Department of Biology, Duke University, 124 Science Dr., Box 90338, Durham, NC 27708 USA
| | - Esther M. Miranda
- Department of Biology, Duke University, 124 Science Dr., Box 90338, Durham, NC 27708 USA
| | - David R. McClay
- Department of Biology, Duke University, 124 Science Dr., Box 90338, Durham, NC 27708 USA
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28
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Formery L, Schubert M, Croce JC. Ambulacrarians and the Ancestry of Deuterostome Nervous Systems. Results Probl Cell Differ 2019; 68:31-59. [PMID: 31598852 DOI: 10.1007/978-3-030-23459-1_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The evolutionary origin and history of metazoan nervous systems has been at the heart of numerous scientific debates for well over a century. This has been a particularly difficult issue to resolve within the deuterostomes, chiefly due to the distinct neural architectures observed within this group of animals. Indeed, deuterosomes feature central nervous systems, apical organs, nerve cords, and basiepidermal nerve nets. Comparative analyses investigating the anatomy and molecular composition of deuterostome nervous systems have nonetheless succeeded in identifying a number of shared and derived features. These analyses have led to the elaboration of diverse theories about the origin and evolutionary history of deuterostome nervous systems. Here, we provide an overview of these distinct theories. Further, we argue that deciphering the adult nervous systems of representatives of all deuterostome phyla, including echinoderms, which have long been neglected in this type of surveys, will ultimately provide answers to the questions concerning the ancestry and evolution of deuterostome nervous systems.
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Affiliation(s)
- Laurent Formery
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Evolution of Intercellular Signaling in Development (EvoInSiDe) Team, Villefranche-sur-Mer, France
| | - Michael Schubert
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Evolution of Intercellular Signaling in Development (EvoInSiDe) Team, Villefranche-sur-Mer, France
| | - Jenifer C Croce
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Evolution of Intercellular Signaling in Development (EvoInSiDe) Team, Villefranche-sur-Mer, France.
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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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Perillo M, Paganos P, Mattiello T, Cocurullo M, Oliveri P, Arnone MI. New Neuronal Subtypes With a "Pre-Pancreatic" Signature in the Sea Urchin Stongylocentrotus purpuratus. Front Endocrinol (Lausanne) 2018; 9:650. [PMID: 30450080 PMCID: PMC6224346 DOI: 10.3389/fendo.2018.00650] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 10/16/2018] [Indexed: 11/24/2022] Open
Abstract
Neurons and pancreatic endocrine cells have a common physiology and express a similar toolkit of transcription factors during development. To explain these common features, it has been hypothesized that pancreatic cells most likely co-opted a pre-existing gene regulatory program from ancestral neurons. To test this idea, we looked for neurons with a "pre-pancreatic" program in an early-branched deuterostome, the sea urchin. Only vertebrates have a proper pancreas, however, our lab previously found that cells with a pancreatic-like signature are localized within the sea urchin embryonic gut. We also found that the pancreatic transcription factors Xlox/Pdx1 and Brn1/2/4 co-localize in a sub-population of ectodermal cells. Here, we find that the ectodermal SpLox+ SpBrn1/2/4 cells are specified as SpSoxC and SpPtf1a neuronal precursors that become the lateral ganglion and the apical organ neurons. Two of the SpLox+ SpBrn1/2/4 cells also express another pancreatic transcription factor, the LIM-homeodomain gene islet-1. Moreover, we find that SpLox neurons produce the neuropeptide SpANP2, and that SpLox regulates SpANP2 expression. Taken together, our data reveal that there is a subset of sea urchin larval neurons with a gene program that predated pancreatic cells. These findings suggest that pancreatic endocrine cells co-opted a regulatory signature from an ancestral neuron that was already present in an early-branched deuterostome.
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Affiliation(s)
| | | | - Teresa Mattiello
- Centre For Life's Origins and Evolution, University College London, London, United Kingdom
| | | | - Paola Oliveri
- Centre For Life's Origins and Evolution, University College London, London, United Kingdom
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Wood NJ, Mattiello T, Rowe ML, Ward L, Perillo M, Arnone MI, Elphick MR, Oliveri P. Neuropeptidergic Systems in Pluteus Larvae of the Sea Urchin Strongylocentrotus purpuratus: Neurochemical Complexity in a "Simple" Nervous System. Front Endocrinol (Lausanne) 2018; 9:628. [PMID: 30410468 PMCID: PMC6209648 DOI: 10.3389/fendo.2018.00628] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 10/02/2018] [Indexed: 12/14/2022] Open
Abstract
The nervous system of the free-living planktonic larvae of sea urchins is relatively "simple," but sufficiently complex to enable sensing of the environment and control of swimming and feeding behaviors. At the pluteus stage of development, the nervous system comprises a central ganglion of serotonergic neurons located in the apical organ and sensory and motor neurons associated with the ciliary band and the gut. Neuropeptides are key mediators of neuronal signaling in nervous systems but currently little is known about neuropeptidergic systems in sea urchin larvae. Analysis of the genome sequence of the sea urchin Strongylocentrotus purpuratus has enabled the identification of 38 genes encoding neuropeptide precursors (NP) in this species. Here we characterize for the first time the expression of nine of these NP genes in S. purpuratus larvae, providing a basis for a functional understanding of the neurochemical organization of the larval nervous system. In order to accomplish this we used single and double in situ hybridization, coupled with immunohistochemistry, to investigate NP gene expression in comparison with known markers (e.g., the neurotransmitter serotonin). Several sub-populations of cells that express one or more NP genes were identified, which are located in the apica organ, at the base of the arms, around the mouth, in the ciliary band and in the mid- and fore-gut. Furthermore, high levels of cell proliferation were observed in neurogenic territories, consistent with an increase in the number of neuropeptidergic cells at late larval stages. This study has revealed that the sea urchin larval nervous system is far more complex at a neurochemical level than was previously known. Our NP gene expression map provides the basis for future work, aimed at understanding the role of diverse neuropeptides in control of various aspects of embryonic and larval behavior.
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Affiliation(s)
- Natalie J. Wood
- Centre for Life's Origins and Evolution, Research Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Teresa Mattiello
- Centre for Life's Origins and Evolution, Research Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
- Stazione Zoologica Anton Dohrn, Naples, Italy
| | - Matthew L. Rowe
- Centre for Life's Origins and Evolution, Research Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Lizzy Ward
- Centre for Life's Origins and Evolution, Research Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
- Research Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | | | | | - Maurice R. Elphick
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Paola Oliveri
- Centre for Life's Origins and Evolution, Research Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
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