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Chou C, Lin CY, Lin CY, Wang A, Fan TP, Wang KT, Yu JK, Su YH. Tracing the evolutionary origin of chordate somites in the hemichordate Ptychodera flava. Integr Comp Biol 2024:icae020. [PMID: 38637301 DOI: 10.1093/icb/icae020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2024] Open
Abstract
Metameric somites are a novel character of chordates with unclear evolutionary origins. In the early branching chordate amphioxus, anterior somites are derived from the paraxial mesodermal cells that bud off the archenteron (i.e., enterocoely) at the end of gastrulation. Development of the anterior somites requires FGF signaling, and distinct somite compartments express orthologs of vertebrate non-axial mesodermal markers. Thus, it has been proposed that the amphioxus anterior somites are homologous to the vertebrate head mesoderm, paraxial mesoderm and lateral plate mesoderm. To trace the evolutionary origin of somites, it is essential to study the chordates' closest sister group, Ambulacraria, which includes hemichordates and echinoderms. The anterior coeloms of hemichordate and sea urchin embryos (respectively called protocoel and coelomic pouches) are also formed by enterocoely and require FGF signals for specification and/or differentiation. In this study, we applied RNA-seq to comprehensively screen for regulatory genes associated with the mesoderm-derived protocoel of the hemichordate Ptychodera flava. We also used a candidate gene approach to identify P. flava orthologs of chordate somite markers. In situ hybridization results showed that many of these candidate genes are expressed in distinct or overlapping regions of the protocoel, which indicates that molecular compartments exist in the hemichordate anterior coelom. Given that the hemichordate protocoel and amphioxus anterior somites share a similar ontogenic process (enterocoely), induction signal (FGF), and characteristic expression of orthologous genes, we propose that these two anterior coeloms are indeed homologous. In the lineage leading to the emergence of chordates, somites likely evolved from enterocoelic, FGF-dependent, and molecularly compartmentalized anterior coeloms of the deuterostome last common ancestor.
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Affiliation(s)
- Cindy Chou
- Institute of Cellular and Organismic Biology, Academia Sinica, 11529 Taipei, Taiwan
| | - Ching-Yi Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, 11529 Taipei, Taiwan
| | - Che-Yi Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, 11529 Taipei, Taiwan
| | - Anthony Wang
- Institute of Cellular and Organismic Biology, Academia Sinica, 11529 Taipei, Taiwan
| | - Tzu-Pei Fan
- Institute of Cellular and Organismic Biology, Academia Sinica, 11529 Taipei, Taiwan
| | - Kuang-Tse Wang
- Institute of Cellular and Organismic Biology, Academia Sinica, 11529 Taipei, Taiwan
| | - Jr-Kai Yu
- Institute of Cellular and Organismic Biology, Academia Sinica, 11529 Taipei, Taiwan
- Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, 26242 Yilan, Taiwan
| | - Yi-Hsien Su
- Institute of Cellular and Organismic Biology, Academia Sinica, 11529 Taipei, Taiwan
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Hoyer J, Kolar K, Athira A, van den Burgh M, Dondorp D, Liang Z, Chatzigeorgiou M. Polymodal sensory perception drives settlement and metamorphosis of Ciona larvae. Curr Biol 2024; 34:1168-1182.e7. [PMID: 38335959 DOI: 10.1016/j.cub.2024.01.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 12/04/2023] [Accepted: 01/16/2024] [Indexed: 02/12/2024]
Abstract
The Earth's oceans brim with an incredible diversity of microscopic lifeforms, including motile planktonic larvae, whose survival critically depends on effective dispersal in the water column and subsequent exploration of the seafloor to identify a suitable settlement site. How their nervous systems mediate sensing of diverse multimodal cues remains enigmatic. Here, we uncover that the tunicate Ciona intestinalis larvae employ ectodermal sensory cells to sense various mechanical and chemical cues. Combining whole-brain imaging and chemogenetics, we demonstrate that stimuli encoded at the periphery are sufficient to drive global brain-state changes to promote or impede both larval attachment and metamorphosis behaviors. The ability of C. intestinalis larvae to leverage polymodal sensory perception to support information coding and chemotactile behaviors may explain how marine larvae make complex decisions despite streamlined nervous systems.
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Affiliation(s)
- Jorgen Hoyer
- Michael Sars Centre, Faculty of Mathematics and Natural Sciences, University of Bergen, Bergen 5006, Norway
| | - Kushal Kolar
- Michael Sars Centre, Faculty of Mathematics and Natural Sciences, University of Bergen, Bergen 5006, Norway
| | - Athira Athira
- Michael Sars Centre, Faculty of Mathematics and Natural Sciences, University of Bergen, Bergen 5006, Norway
| | - Meike van den Burgh
- Michael Sars Centre, Faculty of Mathematics and Natural Sciences, University of Bergen, Bergen 5006, Norway
| | - Daniel Dondorp
- Michael Sars Centre, Faculty of Mathematics and Natural Sciences, University of Bergen, Bergen 5006, Norway
| | - Zonglai Liang
- Michael Sars Centre, Faculty of Mathematics and Natural Sciences, University of Bergen, Bergen 5006, Norway
| | - Marios Chatzigeorgiou
- Michael Sars Centre, Faculty of Mathematics and Natural Sciences, University of Bergen, Bergen 5006, Norway.
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3
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Chung J, Newman-Smith E, Kourakis MJ, Miao Y, Borba C, Medina J, Laurent T, Gallean B, Faure E, Smith WC. A single oscillating proto-hypothalamic neuron gates taxis behavior in the primitive chordate Ciona. Curr Biol 2023; 33:3360-3370.e4. [PMID: 37490920 PMCID: PMC10528541 DOI: 10.1016/j.cub.2023.06.080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/05/2023] [Accepted: 06/29/2023] [Indexed: 07/27/2023]
Abstract
Ciona larvae display a number of behaviors, including negative phototaxis. In negative phototaxis, the larvae first perform short spontaneous rhythmic casting swims. As larvae are cast in a light field, their photoreceptors are directionally shaded by an associated pigment cell, providing a phototactic cue. This then evokes an extended negative taxis swim. We report here that the larval forebrain of Ciona has a previously uncharacterized single slow-oscillating inhibitory neuron (neuron cor-assBVIN78) that projects to the midbrain, where it targets key interneurons of the phototaxis circuit known as the photoreceptor relay neurons. The anatomical location, gene expression, and oscillation of cor-assBVIN78 suggest homology to oscillating neurons of the vertebrate hypothalamus. Ablation of cor-assBVIN78 results in larvae showing extended phototaxis-like swims, even in the absence of phototactic cues. These results indicate that cor-assBVIN78 has a gating activity on phototaxis by projecting temporally oscillating inhibition to the photoreceptor relay neurons. However, in intact larvae, the frequency of cor-assBVIN78 oscillation does not match that of the rhythmic spontaneous swims, indicating that the troughs in oscillations do not themselves initiate swims but rather that cor-assBVIN78 may modulate the phototaxis circuit by filtering out low-level inputs while restricting them temporally to the troughs in inhibition.
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Affiliation(s)
- Janeva Chung
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Erin Newman-Smith
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Matthew J Kourakis
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Yishen Miao
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Cezar Borba
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Juan Medina
- College of Creative Studies, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Tao Laurent
- Laboratoire d'Informatique, de Robotique et de Microélectronique de Montpellier, Université de Montpellier, CNRS, Montpellier, France
| | - Benjamin Gallean
- Centre de Recherche de Biologie cellulaire de Montpellier, Université de Montpellier, CNRS, Montpellier, France
| | - Emmanuel Faure
- Laboratoire d'Informatique, de Robotique et de Microélectronique de Montpellier, Université de Montpellier, CNRS, Montpellier, France
| | - William C Smith
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA; Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
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4
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Somorjai IML, Ehebauer MT, Escrivà H, Garcia-Fernàndez J. JNK Mediates Differentiation, Cell Polarity and Apoptosis During Amphioxus Development by Regulating Actin Cytoskeleton Dynamics and ERK Signalling. Front Cell Dev Biol 2021; 9:749806. [PMID: 34778260 PMCID: PMC8586503 DOI: 10.3389/fcell.2021.749806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/17/2021] [Indexed: 11/13/2022] Open
Abstract
c-Jun N-terminal kinase (JNK) is a multi-functional protein involved in a diverse array of context-dependent processes, including apoptosis, cell cycle regulation, adhesion, and differentiation. It is integral to several signalling cascades, notably downstream of non-canonical Wnt and mitogen activated protein kinase (MAPK) signalling pathways. As such, it is a key regulator of cellular behaviour and patterning during embryonic development across the animal kingdom. The cephalochordate amphioxus is an invertebrate chordate model system straddling the invertebrate to vertebrate transition and is thus ideally suited for comparative studies of morphogenesis. However, next to nothing is known about JNK signalling or cellular processes in this lineage. Pharmacological inhibition of JNK signalling using SP600125 during embryonic development arrests gastrula invagination and causes convergence extension-like defects in axial elongation, particularly of the notochord. Pharynx formation and anterior oral mesoderm derivatives like the preoral pit are also affected. This is accompanied by tissue-specific transcriptional changes, including reduced expression of six3/6 and wnt2 in the notochord, and ectopic wnt11 in neurulating embryos treated at late gastrula stages. Cellular delamination results in accumulation of cells in the gut cavity and a dorsal fin-like protrusion, followed by secondary Caspase-3-mediated apoptosis of polarity-deficient cells, a phenotype only partly rescued by co-culture with the pan-Caspase inhibitor Z-VAD-fmk. Ectopic activation of extracellular signal regulated kinase (ERK) signalling in the neighbours of extruded notochord and neural cells, possibly due to altered adhesive and tensile properties, as well as defects in cellular migration, may explain some phenotypes caused by JNK inhibition. Overall, this study supports conserved functions of JNK signalling in mediating the complex balance between cell survival, apoptosis, differentiation, and cell fate specification during cephalochordate morphogenesis.
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Affiliation(s)
- Ildiko M L Somorjai
- School of Biology, University of St Andrews, St Andrews, United Kingdom.,Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins, Observatoire Océanologique, Banyuls-sur-Mer, France.,Departament de Genètica, Microbiologia i Estadística, University of Barcelona, Barcelona, Spain
| | | | - Hector Escrivà
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins, Observatoire Océanologique, Banyuls-sur-Mer, France
| | - Jordi Garcia-Fernàndez
- Departament de Genètica, Microbiologia i Estadística, University of Barcelona, Barcelona, Spain.,Institut de Biomedicina, University of Barcelona, Barcelona, Spain
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5
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Caccavale F, Annona G, Subirana L, Escriva H, Bertrand S, D'Aniello S. Crosstalk between nitric oxide and retinoic acid pathways is essential for amphioxus pharynx development. eLife 2021; 10:e58295. [PMID: 34431784 PMCID: PMC8387019 DOI: 10.7554/elife.58295] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 07/31/2021] [Indexed: 11/13/2022] Open
Abstract
During animal ontogenesis, body axis patterning is finely regulated by complex interactions among several signaling pathways. Nitric oxide (NO) and retinoic acid (RA) are potent morphogens that play a pivotal role in vertebrate development. Their involvement in axial patterning of the head and pharynx shows conserved features in the chordate phylum. Indeed, in the cephalochordate amphioxus, NO and RA are crucial for the correct development of pharyngeal structures. Here, we demonstrate the functional cooperation between NO and RA that occurs during amphioxus embryogenesis. During neurulation, NO modulates RA production through the transcriptional regulation of Aldh1a.2 that irreversibly converts retinaldehyde into RA. On the other hand, RA directly or indirectly regulates the transcription of Nos genes. This reciprocal regulation of NO and RA pathways is essential for the normal pharyngeal development in amphioxus and it could be conserved in vertebrates.
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Affiliation(s)
- Filomena Caccavale
- Department of Biology and Evolution of Marine Organisms (BEOM), Stazione Zoologica Anton Dohrn NapoliNapoliItaly
| | - Giovanni Annona
- Department of Biology and Evolution of Marine Organisms (BEOM), Stazione Zoologica Anton Dohrn NapoliNapoliItaly
| | - Lucie Subirana
- Sorbonne Université CNRS, Biologie Intégrative des Organismes Marins (BIOM), Observatoire OcéanologiqueBanyuls-sur-MerFrance
| | - Hector Escriva
- Sorbonne Université CNRS, Biologie Intégrative des Organismes Marins (BIOM), Observatoire OcéanologiqueBanyuls-sur-MerFrance
| | - Stephanie Bertrand
- Sorbonne Université CNRS, Biologie Intégrative des Organismes Marins (BIOM), Observatoire OcéanologiqueBanyuls-sur-MerFrance
| | - Salvatore D'Aniello
- Department of Biology and Evolution of Marine Organisms (BEOM), Stazione Zoologica Anton Dohrn NapoliNapoliItaly
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Kawai T, Hashimoto M, Eguchi N, Nishino JM, Jinno Y, Mori-Kreiner R, Aspåker M, Chiba D, Ohtsuka Y, Kawanabe A, Nishino AS, Okamura Y. Heterologous functional expression of ascidian Nav1 channels and close relationship with the evolutionary ancestor of vertebrate Nav channels. J Biol Chem 2021; 296:100783. [PMID: 34000300 PMCID: PMC8192821 DOI: 10.1016/j.jbc.2021.100783] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/01/2021] [Accepted: 05/10/2021] [Indexed: 02/09/2023] Open
Abstract
Voltage-gated sodium channels (Nav1s) are responsible for the initiation and propagation of action potentials in neurons, muscle, and endocrine cells. Many clinically used drugs such as local anesthetics and antiarrhythmics inhibit Nav1s, and a variety of inherited human disorders are caused by mutations in Nav1 genes. Nav1s consist of the main α subunit and several auxiliary β subunits. Detailed information on the structure–function relationships of Nav1 subunits has been obtained through heterologous expression experiments and analyses of protein structures. The basic properties of Nav1s, including their gating and ion permeation, were classically described in the squid giant axon and other invertebrates. However, heterologous functional expression of Nav1s from marine invertebrates has been unsuccessful. Ascidians belong to the Urochordata, a sister group of vertebrates, and the larval central nervous system of ascidians shows a similar plan to that of vertebrates. Here, we report the biophysical properties of ascidian Ciona Nav1 (CiNav1a) heterologously expressed in Xenopus oocytes. CiNav1a exhibited tetrodotoxin-insensitive sodium currents with rapid gating kinetics of activation and inactivation. Furthermore, consistent with the fact that the Ciona genome lacks orthologous genes to vertebrate β subunits, the human β1 subunit did not influence the gating properties when coexpressed with CiNav1a. Interestingly, CiNav1a contains an ankyrin-binding motif in the II–III linker, which can be targeted to the axon initial segment of mammalian cortical neurons. Our findings provide a platform to gain insight into the evolutionary and biophysical properties of Nav1s, which are important for the development of targeted therapeutics.
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Affiliation(s)
- Takafumi Kawai
- Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Masaki Hashimoto
- Graduate School of Frontier Bioscience, Osaka University, Suita, Japan
| | | | - Junko M Nishino
- Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Japan; Department of Bioresources Science, United Graduate School of Agricultural Sciences, Iwate University, Hirosaki, Japan
| | - Yuka Jinno
- Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Risa Mori-Kreiner
- Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Japan
| | | | - Daijiro Chiba
- Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Japan
| | - Yukio Ohtsuka
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan
| | - Akira Kawanabe
- Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Atsuo S Nishino
- Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Japan; Department of Bioresources Science, United Graduate School of Agricultural Sciences, Iwate University, Hirosaki, Japan
| | - Yasushi Okamura
- Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Japan; Graduate School of Frontier Bioscience, Osaka University, Suita, Japan.
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7
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McCoy VE, Wiemann J, Lamsdell JC, Whalen CD, Lidgard S, Mayer P, Petermann H, Briggs DEG. Chemical signatures of soft tissues distinguish between vertebrates and invertebrates from the Carboniferous Mazon Creek Lagerstätte of Illinois. Geobiology 2020; 18:560-565. [PMID: 32347003 DOI: 10.1111/gbi.12397] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 01/17/2020] [Accepted: 03/27/2020] [Indexed: 06/11/2023]
Abstract
The chemical composition of fossil soft tissues is a potentially powerful and yet underutilized tool for elucidating the affinity of problematic fossil organisms. In some cases, it has proven difficult to assign a problematic fossil even to the invertebrates or vertebrates (more generally chordates) based on often incompletely preserved morphology alone, and chemical composition may help to resolve such questions. Here, we use in situ Raman microspectroscopy to investigate the chemistry of a diverse array of invertebrate and vertebrate fossils from the Pennsylvanian Mazon Creek Lagerstätte of Illinois, and we generate a ChemoSpace through principal component analysis (PCA) of the in situ Raman spectra. Invertebrate soft tissues characterized by chitin (polysaccharide) fossilization products and vertebrate soft tissues characterized by protein fossilization products plot in completely separate, non-overlapping regions of the ChemoSpace, demonstrating the utility of certain soft tissue molecular signatures as biomarkers for the original soft tissue composition of fossil organisms. The controversial problematicum Tullimonstrum, known as the Tully Monster, groups with the vertebrates, providing strong evidence of a vertebrate rather than invertebrate affinity.
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Affiliation(s)
- Victoria E McCoy
- Department of Geosciences, University of Wisconsin, Milwaukee, Milwaukee, WI, USA
- Institute of Geosciences, University of Bonn, Bonn, Germany
| | - Jasmina Wiemann
- Department of Geology and Geophysics, Yale University, New Haven, CT, USA
| | - James C Lamsdell
- Department of Geology and Geography, West Virginia University, Morgantown, WV, USA
| | | | | | - Paul Mayer
- Field Museum of Natural History, Chicago, IL, USA
| | - Holger Petermann
- Department of Earth Sciences, Denver Museum of Nature and Science, Colorado Boulevard, Denver, CO, USA
| | - Derek E G Briggs
- Department of Geology and Geophysics, Yale University, New Haven, CT, USA
- Yale Peabody Museum of Natural History, New Haven, CT, USA
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Onuma TA, Hayashi M, Gyoja F, Kishi K, Wang K, Nishida H. A chordate species lacking Nodal utilizes calcium oscillation and Bmp for left-right patterning. Proc Natl Acad Sci U S A 2020; 117:4188-98. [PMID: 32029598 DOI: 10.1073/pnas.1916858117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Larvaceans are chordates with a tadpole-like morphology. In contrast to most chordates of which early embryonic morphology is bilaterally symmetric and the left-right (L-R) axis is specified by the Nodal pathway later on, invariant L-R asymmetry emerges in four-cell embryos of larvaceans. The asymmetric cell arrangements exist through development of the tailbud. The tail thus twists 90° in a counterclockwise direction relative to the trunk, and the tail nerve cord localizes on the left side. Here, we demonstrate that larvacean embryos have nonconventional L-R asymmetries: 1) L- and R-cells of the two-cell embryo had remarkably asymmetric cell fates; 2) Ca2+ oscillation occurred through embryogenesis; 3) Nodal, an evolutionarily conserved left-determining gene, was absent in the genome; and 4) bone morphogenetic protein gene (Bmp) homolog Bmp.a showed right-sided expression in the tailbud and larvae. We also showed that Ca2+ oscillation is required for Bmp.a expression, and that BMP signaling suppresses ectopic expression of neural genes. These results indicate that there is a chordate species lacking Nodal that utilizes Ca2+ oscillation and Bmp.a for embryonic L-R patterning. The right-side Bmp.a expression may have arisen via cooption of conventional BMP signaling in order to restrict neural gene expression on the left side.
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Racioppi C, Wiechecki KA, Christiaen L. Combinatorial chromatin dynamics foster accurate cardiopharyngeal fate choices. eLife 2019; 8:49921. [PMID: 31746740 PMCID: PMC6952182 DOI: 10.7554/elife.49921] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/18/2019] [Indexed: 12/22/2022] Open
Abstract
During embryogenesis, chromatin accessibility profiles control lineage-specific gene expression by modulating transcription, thus impacting multipotent progenitor states and subsequent fate choices. Subsets of cardiac and pharyngeal/head muscles share a common origin in the cardiopharyngeal mesoderm, but the chromatin landscapes that govern multipotent progenitors competence and early fate choices remain largely elusive. Here, we leveraged the simplicity of the chordate model Ciona to profile chromatin accessibility through stereotyped transitions from naive Mesp+ mesoderm to distinct fate-restricted heart and pharyngeal muscle precursors. An FGF-Foxf pathway acts in multipotent progenitors to establish cardiopharyngeal-specific patterns of accessibility, which govern later heart vs. pharyngeal muscle-specific expression profiles, demonstrating extensive spatiotemporal decoupling between early cardiopharyngeal enhancer accessibility and late cell-type-specific activity. We found that multiple cis-regulatory elements, with distinct chromatin accessibility profiles and motif compositions, are required to activate Ebf and Tbx1/10, two key determinants of cardiopharyngeal fate choices. We propose that these 'combined enhancers' foster spatially and temporally accurate fate choices, by increasing the repertoire of regulatory inputs that control gene expression, through either accessibility and/or activity.
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Affiliation(s)
- Claudia Racioppi
- Center for Developmental Genetics, Department of Biology, New York University, New York, United States
| | - Keira A Wiechecki
- Center for Developmental Genetics, Department of Biology, New York University, New York, United States
| | - Lionel Christiaen
- Center for Developmental Genetics, Department of Biology, New York University, New York, United States
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Shirley B, Grohganz M, Bestmann M, Jarochowska E. Wear, tear and systematic repair: testing models of growth dynamics in conodonts with high-resolution imaging. Proc Biol Sci 2018; 285:rspb.2018.1614. [PMID: 30185642 DOI: 10.1098/rspb.2018.1614] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 08/14/2018] [Indexed: 11/12/2022] Open
Abstract
Conodont elements are the earliest mineralized vertebrate dental tools and the only ones capable of extensive repair. Two models of conodont growth, as well as the presence of a larval stage, have been hypothesized. We analysed normally and pathologically developed elements to test these hypotheses and identified three ontogenetic stages characterized by different anisometric growth and morphology. The distinction of these stages is independently corroborated by differences in tissue strontium (Sr) content. The onset of the last stage is marked by the appearance of wear resulting from mechanical food digestion. At least five episodes of damage and repair could be identified in the normally developed specimen. In the pathological element, function was compromised by the development of abnormal denticles. This development can be reconstructed as addition of new growth centres out of the main growth axis during an episode of renewed growth. Our findings support the model of periodic retraction of elements and addition of new growth centres. Changes in Sr content coincident with distinct morphology and lack of wear in the early life stage indicate that conodonts might have assumed their mature feeding habit of predators or scavengers after an initial larval stage characterized by a different feeding mode.
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Affiliation(s)
- Bryan Shirley
- Fachgruppe Paläoumwelt, GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg, Loewenichstr. 28, 91054 Erlangen, Germany
| | - Madleen Grohganz
- Fachgruppe Paläoumwelt, GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg, Loewenichstr. 28, 91054 Erlangen, Germany
| | - Michel Bestmann
- Fachgruppe Strukturgeologie, GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg, Loewenichstr. 28, 91054 Erlangen, Germany
| | - Emilia Jarochowska
- Fachgruppe Paläoumwelt, GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg, Loewenichstr. 28, 91054 Erlangen, Germany
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11
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Ryan K, Lu Z, Meinertzhagen IA. Circuit Homology between Decussating Pathways in the Ciona Larval CNS and the Vertebrate Startle-Response Pathway. Curr Biol 2017; 27:721-728. [PMID: 28216318 DOI: 10.1016/j.cub.2017.01.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Revised: 12/22/2016] [Accepted: 01/13/2017] [Indexed: 10/20/2022]
Abstract
Comparing synaptic circuits and networks between brains of different animal groups helps us derive an understanding of how nervous systems might have evolved. The circuits of the startle response pathway in the brains of tailed vertebrates are known from electrophysiological studies on the giant reticulospinal Mauthner cells (M-cells). To identify morphological counterparts in chordate tunicates, a sister group of vertebrates [1, 2], we have compiled a densely reconstructed connectome (defined in [3]) for the CNS in the tadpole larva of Ciona intestinalis (L.), using ssEM [4]. The dorsal, tubular CNS of the ∼1-mm tadpole larva is built on a similar plan to vertebrates, its neurons distributed rostrocaudally in three centers, a brain vesicle, motor ganglion, and caudal nerve cord [5]. A single pair of descending decussating neurons, ddNs, found in the motor ganglion, have similarities to reticulospinal neurons descending from the vertebrate hindbrain to the spinal cord. The pre- and postsynaptic connections and circuits of these ddNs support their homology with decussating vertebrate M-cells. Network analysis reveals that, like M-cells, ddNs receive mechanosensory input from the peripheral nervous system and provide input to motoneurons, premotor interneurons, and ascending commissural inhibitory neurons (ACINs). These circuits uncover a putative homologous startle network in the Ciona tadpole. However, differences in circuits, including a lack of bilateral symmetry in their network, and convergence of inputs from left and right sides, raise questions about the relationship between form and function, and are a possible outcome of the tiny number of neurons in ascidian larvae.
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Affiliation(s)
- Kerrianne Ryan
- Department of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, NS B3H 4R2, Canada; Department of Biology, Life Sciences Centre, Dalhousie University, Halifax, NS B3H 4R2, Canada.
| | - Zhiyuan Lu
- Department of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Ian A Meinertzhagen
- Department of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, NS B3H 4R2, Canada; Department of Biology, Life Sciences Centre, Dalhousie University, Halifax, NS B3H 4R2, Canada.
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12
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Ogura Y, Sasakura Y. Switching the rate and pattern of cell division for neural tube closure. Neurogenesis (Austin) 2016; 3:e1235938. [PMID: 27928549 PMCID: PMC5120683 DOI: 10.1080/23262133.2016.1235938] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 09/04/2016] [Accepted: 09/07/2016] [Indexed: 01/04/2023]
Abstract
The morphogenetic movement associated with neural tube closure (NTC) requires both positive and negative regulations of cell proliferation. The dual requirement of cell division control during NTC underscores the importance of the developmental control of cell division. In the chordate ascidian, midline fusions of the neural ectoderm and surface ectoderm (SE) proceed in the posterior-to-anterior direction, followed by a single wave of asynchronous and patterned cell division in SE. Before NTC, SE exhibits synchronous mitoses; disruption of the synchrony causes a failure of NTC. Therefore, NTC is the crucial turning point at which SE switches from synchronous to patterned mitosis. Our recent work discovered that the first sign of patterned cell division in SE appears was an asynchronous S-phase length along the anterior-posterior axis before NTC: the asynchrony of S-phase is offset by the compensatory G2-phase length, thus maintaining the apparent synchrony of cell division. By the loss of compensatory G2 phase, the synchronized cell division harmoniously switches to a patterned cell division at the onset of NTC. Here we review the developmental regulation of rate and pattern of cell division during NTC with emphasis on the switching mechanism identified in our study.
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Affiliation(s)
- Yosuke Ogura
- Shimoda Marine Research Center, University of Tsukuba , Shimoda, Shizuoka, Japan
| | - Yasunori Sasakura
- Shimoda Marine Research Center, University of Tsukuba , Shimoda, Shizuoka, Japan
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13
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Abstract
RNA interference is widely employed as a gene-silencing system in eukaryotes for host defence against invading nucleic acids. In response to invading double-stranded RNA (dsRNA), mRNA is degraded in sequence-specific manner. So far, however, DNA interference (DNAi) has been reported only in plants, ciliates and archaea, and has not been explored in Metazoa. Here, we demonstrate that linear double-stranded DNA promotes both sequence-specific transcription blocking and mRNA degradation in developing embryos of the appendicularian Oikopleura dioica. Introduced polymerase chain reaction (PCR) products or linearized plasmids encoding Brachyury induced tail malformation and mRNA degradation. This malformation was also promoted by DNA fragments of the putative 5'-flanking region and intron without the coding region. PCR products encoding Zic-like1 and acetylcholine esterase also induced loss of sensory organ and muscle acetylcholinesterase activity, respectively. Co-injection of mRNA encoding EGFP and mCherry, and PCR products encoding these fluorescent proteins, induced sequence-specific decrease in the green or red fluorescence, respectively. These results suggest that O. dioica possesses a defence system against exogenous DNA and RNA, and that DNA fragment-induced gene silencing would be mediated through transcription blocking as well as mRNA degradation. This is the first report of DNAi in Metazoa.
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Affiliation(s)
- Tatsuya Omotezako
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Takeshi A Onuma
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Hiroki Nishida
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
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14
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Sekiguchi T, Kuwasako K, Ogasawara M, Takahashi H, Matsubara S, Osugi T, Muramatsu I, Sasayama Y, Suzuki N, Satake H. Evidence for Conservation of the Calcitonin Superfamily and Activity-regulating Mechanisms in the Basal Chordate Branchiostoma floridae: INSIGHTS INTO THE MOLECULAR AND FUNCTIONAL EVOLUTION IN CHORDATES. J Biol Chem 2015; 291:2345-56. [PMID: 26644465 DOI: 10.1074/jbc.m115.664003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Indexed: 11/06/2022] Open
Abstract
The calcitonin (CT)/CT gene-related peptide (CGRP) family is conserved in vertebrates. The activities of this peptide family are regulated by a combination of two receptors, namely the calcitonin receptor (CTR) and the CTR-like receptor (CLR), and three receptor activity-modifying proteins (RAMPs). Furthermore, RAMPs act as escort proteins by translocating CLR to the cell membrane. Recently, CT/CGRP family peptides have been identified or inferred in several invertebrates. However, the molecular characteristics and relevant functions of the CTR/CLR and RAMPs in invertebrates remain unclear. In this study, we identified three CT/CGRP family peptides (Bf-CTFPs), one CTR/CLR-like receptor (Bf-CTFP-R), and three RAMP-like proteins (Bf-RAMP-LPs) in the basal chordate amphioxus (Branchiostoma floridae). The Bf-CTFPs were shown to possess an N-terminal circular region typical of the CT/CGRP family and a C-terminal Pro-NH2. The Bf-CTFP genes were expressed in the central nervous system and in endocrine cells of the midgut, indicating that Bf-CTFPs serve as brain and/or gut peptides. Cell surface expression of the Bf-CTFP-R was enhanced by co-expression with each Bf-RAMP-LP. Furthermore, Bf-CTFPs activated Bf-CTFP-R·Bf-RAMP-LP complexes, resulting in cAMP accumulation. These results confirmed that Bf-RAMP-LPs, like vertebrate RAMPs, are prerequisites for the function and translocation of the Bf-CTFP-R. The relative potencies of the three peptides at each receptor were similar. Bf-CTFP2 was a potent ligand at all receptors in cAMP assays. Bf-RAMP-LP effects on ligand potency order were distinct to vertebrate CGRP/adrenomedullin/amylin receptors. To the best of our knowledge, this is the first molecular and functional characterization of an authentic invertebrate CT/CGRP family receptor and RAMPs.
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Affiliation(s)
- Toshio Sekiguchi
- From the Noto Marine Laboratory, Division of Marine Environmental Studies, Institute of Nature and Environmental Technology, Kanazawa University, Housu-gun, Ishikawa 927-0553, Japan,
| | - Kenji Kuwasako
- the Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, Miyazaki 889-1692, Japan
| | - Michio Ogasawara
- the Department of Nanobiology, Graduate School of Advanced Integration Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Hiroki Takahashi
- the Laboratory of Morphogenesis, National Institute for Basic Biology, 38 Nishigonaka Myodaiji, Okazaki 444-8585, Japan
| | - Shin Matsubara
- the Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1, Seikadai, Seika-cho, Soraku-gun, Kyoto 619-0284, Japan, and
| | - Tomohiro Osugi
- the Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1, Seikadai, Seika-cho, Soraku-gun, Kyoto 619-0284, Japan, and
| | - Ikunobu Muramatsu
- the Department of Pharmacology, School of Medicine, Kanazawa Medical University, Uchinada, Ishikawa 920-0293, Japan
| | - Yuichi Sasayama
- From the Noto Marine Laboratory, Division of Marine Environmental Studies, Institute of Nature and Environmental Technology, Kanazawa University, Housu-gun, Ishikawa 927-0553, Japan
| | - Nobuo Suzuki
- From the Noto Marine Laboratory, Division of Marine Environmental Studies, Institute of Nature and Environmental Technology, Kanazawa University, Housu-gun, Ishikawa 927-0553, Japan
| | - Honoo Satake
- the Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1, Seikadai, Seika-cho, Soraku-gun, Kyoto 619-0284, Japan, and
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15
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Abstract
The ascidian Ciona intestinalis, commonly known as a 'sea squirt', has become an important model for embryological studies, offering a simple blueprint for chordate development. As a model organism, it offers the following: a small, compact genome; a free swimming larva with only about 2600 cells; and an embryogenesis that unfolds according to a predictable program of cell division. Moreover, recent phylogenies reveal that C. intestinalis occupies a privileged branch in the tree of life: it is our nearest invertebrate relative. Here, we provide an organismal perspective of C. intestinalis, highlighting aspects of its life history and habitat-from its brief journey as a larva to its radical metamorphosis into adult form-and relate these features to its utility as a laboratory model.
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Affiliation(s)
- Matthew J Kourakis
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States
| | - William C Smith
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States
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16
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Yanagi T, Ito K, Nishihara A, Minamino R, Mori S, Sumida M, Hashimoto C. The Spemann organizer meets the anterior-most neuroectoderm at the equator of early gastrulae in amphibian species. Dev Growth Differ 2015; 57:218-31. [PMID: 25754292 PMCID: PMC4402005 DOI: 10.1111/dgd.12200] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 01/08/2015] [Accepted: 01/20/2015] [Indexed: 11/17/2022]
Abstract
The dorsal blastopore lip (known as the Spemann organizer) is important for making the body plan in amphibian gastrulation. The organizer is believed to involute inward and migrate animally to make physical contact with the prospective head neuroectoderm at the blastocoel roof of mid- to late-gastrula. However, we found that this physical contact was already established at the equatorial region of very early gastrula in a wide variety of amphibian species. Here we propose a unified model of amphibian gastrulation movement. In the model, the organizer is present at the blastocoel roof of blastulae, moves vegetally to locate at the region that lies from the blastocoel floor to the dorsal lip at the onset of gastrulation. The organizer located at the blastocoel floor contributes to the anterior axial mesoderm including the prechordal plate, and the organizer at the dorsal lip ends up as the posterior axial mesoderm. During the early step of gastrulation, the anterior organizer moves to establish the physical contact with the prospective neuroectoderm through the “subduction and zippering” movements. Subduction makes a trench between the anterior organizer and the prospective neuroectoderm, and the tissues face each other via the trench. Zippering movement, with forming Brachet's cleft, gradually closes the gap to establish the contact between them. The contact is completed at the equator of early gastrulae and it continues throughout the gastrulation. After the contact is established, the dorsal axis is formed posteriorly, but not anteriorly. The model also implies the possibility of constructing a common model of gastrulation among chordate species.
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Affiliation(s)
- Takanori Yanagi
- JT Biohistory Research Hall, 1-1 Murasaki-cho, Takatsuki, Osaka, 569-1125, Japan; Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
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17
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Niimura Y. On the origin and evolution of vertebrate olfactory receptor genes: comparative genome analysis among 23 chordate species. Genome Biol Evol 2009; 1:34-44. [PMID: 20333175 PMCID: PMC2817399 DOI: 10.1093/gbe/evp003] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/25/2009] [Indexed: 12/27/2022] Open
Abstract
Olfaction is a primitive sense in organisms. Both vertebrates and insects have
receptors for detecting odor molecules in the environment, but the evolutionary
origins of these genes are different. Among studied vertebrates, mammals have
∼1,000 olfactory receptor (OR) genes, whereas teleost fishes have much
smaller (∼100) numbers of OR genes. To investigate the origin and
evolution of vertebrate OR genes, I attempted to determine near-complete OR gene
repertoires by searching whole-genome sequences of 14 nonmammalian chordates,
including cephalochordates (amphioxus), urochordates (ascidian and larvacean),
and vertebrates (sea lamprey, elephant shark, five teleost fishes, frog, lizard,
and chicken), followed by a large-scale phylogenetic analysis in conjunction
with mammalian OR genes identified from nine species. This analysis showed that
the amphioxus has >30 vertebrate-type OR genes though it lacks
distinctive olfactory organs, whereas all OR genes appear to have been lost in
the urochordate lineage. Some groups of genes (θ, κ, and
λ) that are phylogenetically nested within vertebrate OR genes showed
few gene gains and losses, which is in sharp contrast to the evolutionary
pattern of OR genes, suggesting that they are actually non-OR genes. Moreover,
the analysis demonstrated a great difference in OR gene repertoires between
aquatic and terrestrial vertebrates, reflecting the necessity for the detection
of water-soluble and airborne odorants, respectively. However, a minor group
(β) of genes that are atypically present in both aquatic and
terrestrial vertebrates was also found. These findings should provide a critical
foundation for further physiological, behavioral, and evolutionary studies of
olfaction in various organisms.
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Affiliation(s)
- Yoshihito Niimura
- Department of Bioinformatics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan.
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18
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Kourakis MJ, Smith WC. A conserved role for FGF signaling in chordate otic/atrial placode formation. Dev Biol 2007; 312:245-57. [PMID: 17959164 PMCID: PMC2169521 DOI: 10.1016/j.ydbio.2007.09.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Revised: 09/12/2007] [Accepted: 09/13/2007] [Indexed: 10/22/2022]
Abstract
The widely held view that neurogenic placodes are vertebrate novelties has been challenged by morphological and molecular data from tunicates suggesting that placodes predate the vertebrate divergence. Here, we examine requirements for the development of the tunicate atrial siphon primordium, thought to share homology with the vertebrate otic placode. In vertebrates, FGF signaling is required for otic placode induction and for later events following placode invagination, including elaboration and patterning of the inner ear. We show that results from perturbation of the FGF pathway in the ascidian Ciona support a similar role for this pathway: inhibition with MEK or Fgfr inhibitor at tailbud stages in Ciona results in a larva which fails to form atrial placodes; inhibition during metamorphosis disrupts development of the atrial siphon and gill slits, structures which form where invaginated atrial siphon ectoderm apposes pharyngeal endoderm. We show that laser ablation of atrial primordium ectoderm also results in a failure to form gill slits in the underlying endoderm. Our data suggest interactions required for formation of the atrial siphon and highlight the role of atrial ectoderm during gill slit morphogenesis.
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Affiliation(s)
- Matthew J Kourakis
- Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
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19
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Meedel TH, Chang P, Yasuo H. Muscle development in Ciona intestinalis requires the b-HLH myogenic regulatory factor gene Ci-MRF. Dev Biol 2007; 302:333-44. [PMID: 17055476 PMCID: PMC1797879 DOI: 10.1016/j.ydbio.2006.09.043] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Revised: 09/22/2006] [Accepted: 09/22/2006] [Indexed: 11/21/2022]
Abstract
The activity of myogenic regulatory factor (MRF) genes is essential for vertebrate muscle development, whereas invertebrate muscle development is largely independent of MRF function. This difference indicates that myogenesis is controlled by distinct regulatory mechanisms in these two groups of animals. Here we used overexpression and gene knockdown to investigate the role in embryonic myogenesis of the single MRF gene of the invertebrate chordate Ciona intestinalis (Ci-MRF). Injection of Ci-MRF mRNA into eggs resulted in increased embryonic muscle-specific gene activity and revealed the myogenic activity of Ci-MRF by inducing the expression of four muscle marker genes, Acetylcholinesterase, Actin, Troponin I, and Myosin Light Chain in non-muscle lineages. Conversely, inhibiting Ci-MRF activity with antisense morpholinos down-regulated the expression of these genes. Consistent with the effects of morpholinos on muscle gene activity, larvae resulting from morpholino injection were paralyzed and their "muscle" cells lacked myofibrils. We conclude that Ci-MRF is required for larval tail muscle development and thus that an MRF-dependent myogenic regulatory network probably existed in the ancestor of tunicates and vertebrates. This possibility raises the question of whether the earliest myogenic regulatory networks were MRF-dependent or MRF-independent.
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Affiliation(s)
- Thomas H Meedel
- Department of Biology, Rhode Island College, Providence, RI, USA.
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