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Wang D, Qiang Y, Guo J, Vannier J, Song Z, Peng J, Zhang B, Sun J, Yu Y, Zhang Y, Zhang T, Yang X, Han J. Early evolution of the ecdysozoan body plan. eLife 2024; 13:RP94709. [PMID: 38976315 PMCID: PMC11231812 DOI: 10.7554/elife.94709] [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] [Indexed: 07/09/2024] Open
Abstract
Extant ecdysozoans (moulting animals) are represented by a great variety of soft-bodied or articulated organisms that may or may not have appendages. However, controversies remain about the vermiform nature (i.e. elongated and tubular) of their ancestral body plan. We describe here Beretella spinosa gen. et sp. nov. a tiny (maximal length 3 mm) ecdysozoan from the lowermost Cambrian, Yanjiahe Formation, South China, characterized by an unusual sack-like appearance, single opening, and spiny ornament. Beretella spinosa gen. et sp. nov has no equivalent among animals, except Saccorhytus coronarius, also from the basal Cambrian. Phylogenetic analyses resolve both fossil species as a sister group (Saccorhytida) to all known Ecdysozoa, thus suggesting that ancestral ecdysozoans may have been non-vermiform animals. Saccorhytids are likely to represent an early off-shot along the stem-line Ecdysozoa. Although it became extinct during the Cambrian, this animal lineage provides precious insight into the early evolution of Ecdysozoa and the nature of the earliest representatives of the group.
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Affiliation(s)
- Deng Wang
- State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life & Environments and Department of Geology, Northwest University, Xi'an, China
| | - Yaqin Qiang
- School of Earth Science and Resources, Key Laboratory of Western China's Mineral Resources and Geological Engineering, Ministry of Education, Chang'an University, Xi'an, China
| | - Junfeng Guo
- School of Earth Science and Resources, Key Laboratory of Western China's Mineral Resources and Geological Engineering, Ministry of Education, Chang'an University, Xi'an, China
| | - Jean Vannier
- Université de Lyon, Université Claude Bernard Lyon 1, ENS de Lyon, CNRS, Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement (CNRS-UMR 5276), Villeurbanne, France
| | - Zuchen Song
- School of Earth Science and Resources, Key Laboratory of Western China's Mineral Resources and Geological Engineering, Ministry of Education, Chang'an University, Xi'an, China
| | - Jiaxin Peng
- School of Earth Science and Resources, Key Laboratory of Western China's Mineral Resources and Geological Engineering, Ministry of Education, Chang'an University, Xi'an, China
| | - Boyao Zhang
- School of Earth Science and Resources, Key Laboratory of Western China's Mineral Resources and Geological Engineering, Ministry of Education, Chang'an University, Xi'an, China
| | - Jie Sun
- State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life & Environments and Department of Geology, Northwest University, Xi'an, China
- School of Earth Science and Resources, Key Laboratory of Western China's Mineral Resources and Geological Engineering, Ministry of Education, Chang'an University, Xi'an, China
| | - Yilun Yu
- Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yiheng Zhang
- School of Information Science and Technology, Northwest University, Xi'an, China
| | - Tao Zhang
- School of Information Science and Technology, Northwest University, Xi'an, China
| | - Xiaoguang Yang
- State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life & Environments and Department of Geology, Northwest University, Xi'an, China
| | - Jian Han
- State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life & Environments and Department of Geology, Northwest University, Xi'an, China
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2
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Clarke DN, Formery L, Lowe CJ. See-Star: a versatile hydrogel-based protocol for clearing large, opaque and calcified marine invertebrates. EvoDevo 2024; 15:8. [PMID: 38918798 PMCID: PMC11201320 DOI: 10.1186/s13227-024-00228-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 05/28/2024] [Indexed: 06/27/2024] Open
Abstract
Studies of morphology and developmental patterning in adult stages of many invertebrates are hindered by opaque structures, such as shells, skeletal elements, and pigment granules that block or refract light and necessitate sectioning for observation of internal features. An inherent challenge in studies relying on surgical approaches is that cutting tissue is semi-destructive, and delicate structures, such as axonal processes within neural networks, are computationally challenging to reconstruct once disrupted. To address this problem, we developed See-Star, a hydrogel-based tissue clearing protocol to render the bodies of opaque and calcified invertebrates optically transparent while preserving their anatomy in an unperturbed state, facilitating molecular labeling and observation of intact organ systems. The resulting protocol can clear large (> 1 cm3) specimens to enable deep-tissue imaging, and is compatible with molecular techniques, such as immunohistochemistry and in situ hybridization to visualize protein and mRNA localization. To test the utility of this method, we performed a whole-mount imaging study of intact nervous systems in juvenile echinoderms and molluscs and demonstrate that See-Star allows for comparative studies to be extended far into development, facilitating insights into the anatomy of juveniles and adults that are usually not amenable to whole-mount imaging.
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Affiliation(s)
- D N Clarke
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA.
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - L Formery
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
| | - C J Lowe
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
- Chan Zuckerberg BioHub, San Francisco, CA, USA
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3
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Zhang H, Xiao S, Eriksson ME, Duan B, Maas A. Musculature of an Early Cambrian cycloneuralian animal. Proc Biol Sci 2023; 290:20231803. [PMID: 37817588 PMCID: PMC10565385 DOI: 10.1098/rspb.2023.1803] [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: 08/10/2023] [Accepted: 09/18/2023] [Indexed: 10/12/2023] Open
Abstract
Cycloneuralians are ecdysozoans with a fossil record extending to the Early Cambrian Fortunian Age and represented mostly by cuticular integuments. However, internal anatomies of Fortunian cycloneuralians are virtually unknown, hampering our understanding of their functional morphology and phylogenetic relationships. Here we report the exceptional preservation of cycloneuralian introvert musculature in Fortunian rocks of South China. The musculature consists of an introvert body-wall muscular grid of four circular and 36 radially arranged longitudinal muscle bundles, as well as an introvert circular muscle associated with 19 roughly radially arranged, short retractors. Collectively, these features support at least a scalidophoran affinity, and the absence of muscles associated with a mouth cone and scalids further indicates a priapulan affinity. As in modern scalidophorans, the fossil musculature, and particularly the introvert circular muscle retractors, may have controlled introvert inversion and facilitated locomotion and feeding. This work supports the evolution of scalidophoran-like or priapulan-like introvert musculature in cycloneuralians at the beginning of the Cambrian Period.
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Affiliation(s)
- Huaqiao Zhang
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China
| | - Shuhai Xiao
- Department of Geosciences, Virginia Tech, Blacksburg, VA 24061, USA
| | | | - Baichuan Duan
- Key Laboratory of Marine Geology and Metallogeny, First Institute of Oceanography, Ministry of Natural Resource, Qingdao 266061, People's Republic of China
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4
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Heppert JK, Lickwar CR, Tillman MC, Davis BR, Davison JM, Lu HY, Chen W, Busch-Nentwich EM, Corcoran DL, Rawls JF. Conserved roles for Hnf4 family transcription factors in zebrafish development and intestinal function. Genetics 2022; 222:iyac133. [PMID: 36218393 PMCID: PMC9713462 DOI: 10.1093/genetics/iyac133] [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: 07/14/2022] [Accepted: 07/20/2022] [Indexed: 12/13/2022] Open
Abstract
Transcription factors play important roles in the development of the intestinal epithelium and its ability to respond to endocrine, nutritional, and microbial signals. Hepatocyte nuclear factor 4 family nuclear receptors are liganded transcription factors that are critical for the development and function of multiple digestive organs in vertebrates, including the intestinal epithelium. Zebrafish have 3 hepatocyte nuclear factor 4 homologs, of which, hnf4a was previously shown to mediate intestinal responses to microbiota in zebrafish larvae. To discern the functions of other hepatocyte nuclear factor 4 family members in zebrafish development and intestinal function, we created and characterized mutations in hnf4g and hnf4b. We addressed the possibility of genetic redundancy amongst these factors by creating double and triple mutants which showed different rates of survival, including apparent early lethality in hnf4a; hnf4b double mutants and triple mutants. RNA sequencing performed on digestive tracts from single and double mutant larvae revealed extensive changes in intestinal gene expression in hnf4a mutants that were amplified in hnf4a; hnf4g mutants, but limited in hnf4g mutants. Changes in hnf4a and hnf4a; hnf4g mutants were reminiscent of those seen in mice including decreased expression of genes involved in intestinal function and increased expression of cell proliferation genes, and were validated using transgenic reporters and EdU labeling in the intestinal epithelium. Gnotobiotics combined with RNA sequencing also showed hnf4g has subtler roles than hnf4a in host responses to microbiota. Overall, phenotypic changes in hnf4a single mutants were strongly enhanced in hnf4a; hnf4g double mutants, suggesting a conserved partial genetic redundancy between hnf4a and hnf4g in the vertebrate intestine.
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Affiliation(s)
- Jennifer K Heppert
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Medicine, Division of Gastroenterology and Hepatology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Colin R Lickwar
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC 27710, USA
| | - Matthew C Tillman
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC 27710, USA
| | - Briana R Davis
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC 27710, USA
| | - James M Davison
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC 27710, USA
| | - Hsiu-Yi Lu
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC 27710, USA
| | - Wei Chen
- Center for Genomics and Computational Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | | | - David L Corcoran
- Center for Genomics and Computational Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - John F Rawls
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC 27710, USA
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Dong XP, Duan B, Liu J, Donoghue PCJ. Internal anatomy of a fossilized embryonic stage of the Cambrian-Ordovician scalidophoran Markuelia. ROYAL SOCIETY OPEN SCIENCE 2022; 9:220115. [PMID: 36249341 PMCID: PMC9532980 DOI: 10.1098/rsos.220115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 09/14/2022] [Indexed: 06/16/2023]
Abstract
The Wangcun fossil Lagerstätte in Hunan, South China, has yielded hundreds of fossilized embryos of Markuelia hunanensis representing different developmental stages. Internal tissues have only rarely been observed, impeding further understanding of the soft tissue anatomy, phylogenetic affinity and evolutionary significance of Markuelia. In this study, we used synchrotron radiation X-ray tomographic microscopy (SRXTM) to study a new collection of fossil embryos from the Wangcun fossil Lagerstätte. We describe specimens exhibiting a spectrum of preservation states, the best of which preserves palisade structures underneath the cuticle of the head and tail, distinct from patterns of centripetal mineralization of the cuticle and centrifugal mineralization of hypha-like structures, seen elsewhere in this specimen and other fossils within the same assemblage. Our computed tomographic reconstruction of these mineralization phases preserves the gross morphology of (i) longitudinal structures associated with the tail spines, which we interpret as the proximal ends of longitudinal muscles, and (ii) a ring-shaped structure internal to the introvert, which we interpret as a ring-shaped brain, as anticipated of the cycloneuralian affinity of Markuelia. This is the first record of a fossilized nervous system in a scalidophoran, and the first instance in Orsten-style preservation, opening the potential for further such records within this widespread mode of high-fidelity three-dimensional preservation.
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Affiliation(s)
- Xi-ping Dong
- School of Earth and Space Science, Peking University, Beijing 100871, People's Republic of China
| | - Baichuan Duan
- Key Laboratory of Marine Geology and Metallogeny, First Institute of Oceanography, Ministry of Natural Resource, Qingdao 266061, People's Republic of China
| | - Jianbo Liu
- School of Earth and Space Science, Peking University, Beijing 100871, People's Republic of China
| | - Philip C. J. Donoghue
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
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6
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Schulreich SM, Salamanca-Díaz DA, Zieger E, Calcino AD, Wanninger A. A mosaic of conserved and novel modes of gene expression and morphogenesis in mesoderm and muscle formation of a larval bivalve. ORG DIVERS EVOL 2022; 22:893-913. [PMID: 36398106 PMCID: PMC9649484 DOI: 10.1007/s13127-022-00569-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/26/2022] [Indexed: 10/17/2022]
Abstract
The mesoderm gives rise to several key morphological features of bilaterian animals including endoskeletal elements and the musculature. A number of regulatory genes involved in mesoderm and/or muscle formation (e.g., Brachyury (Bra), even-skipped (eve), Mox, myosin II heavy chain (mhc)) have been identified chiefly from chordates and the ecdysozoans Drosophila and Caenorhabditis elegans, but data for non-model protostomes, especially those belonging to the ecdysozoan sister clade, Lophotrochozoa (e.g., flatworms, annelids, mollusks), are only beginning to emerge. Within the lophotrochozoans, Mollusca constitutes the most speciose and diverse phylum. Interestingly, however, information on the morphological and molecular underpinnings of key ontogenetic processes such as mesoderm formation and myogenesis remains scarce even for prominent molluscan sublineages such as the bivalves. Here, we investigated myogenesis and developmental expression of Bra, eve, Mox, and mhc in the quagga mussel Dreissena rostriformis, an invasive freshwater bivalve and an emerging model in invertebrate evodevo. We found that all four genes are expressed during mesoderm formation, but some show additional, individual sites of expression during ontogeny. While Mox and mhc are involved in early myogenesis, eve is also expressed in the embryonic shell field and Bra is additionally present in the foregut. Comparative analysis suggests that Mox has an ancestral role in mesoderm and possibly muscle formation in bilaterians, while Bra and eve are conserved regulators of mesoderm development of nephrozoans (protostomes and deuterostomes). The fully developed Dreissena veliger larva shows a highly complex muscular architecture, supporting a muscular ground pattern of autobranch bivalve larvae that includes at least a velum muscle ring, three or four pairs of velum retractors, one or two pairs of larval retractors, two pairs of foot retractors, a pedal plexus, possibly two pairs of mantle retractors, and the muscles of the pallial line, as well as an anterior and a posterior adductor. As is typical for their molluscan kin, remodelling and loss of prominent larval features such as the velum musculature and various retractor systems appear to be also common in bivalves. Supplementary information The online version contains supplementary material available at 10.1007/s13127-022-00569-5.
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Affiliation(s)
- Stephan M. Schulreich
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - David A. Salamanca-Díaz
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Elisabeth Zieger
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Andrew D. Calcino
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Andreas Wanninger
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
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7
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Janssen R, Pechmann M, Turetzek N. A chelicerate Wnt gene expression atlas: novel insights into the complexity of arthropod Wnt-patterning. EvoDevo 2021; 12:12. [PMID: 34753512 PMCID: PMC8579682 DOI: 10.1186/s13227-021-00182-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 10/27/2021] [Indexed: 11/24/2022] Open
Abstract
The Wnt genes represent a large family of secreted glycoprotein ligands that date back to early animal evolution. Multiple duplication events generated a set of 13 Wnt families of which 12 are preserved in protostomes. Embryonic Wnt expression patterns (Wnt-patterning) are complex, representing the plentitude of functions these genes play during development. Here, we comprehensively investigated the embryonic expression patterns of Wnt genes from three species of spiders covering both main groups of true spiders, Haplogynae and Entelegynae, a mygalomorph species (tarantula), as well as a distantly related chelicerate outgroup species, the harvestman Phalangium opilio. All spiders possess the same ten classes of Wnt genes, but retained partially different sets of duplicated Wnt genes after whole genome duplication, some of which representing impressive examples of sub- and neo-functionalization. The harvestman, however, possesses a more complete set of 11 Wnt genes but with no duplicates. Our comprehensive data-analysis suggests a high degree of complexity and evolutionary flexibility of Wnt-patterning likely providing a firm network of mutational protection. We discuss the new data on Wnt gene expression in terms of their potential function in segmentation, posterior elongation, and appendage development and critically review previous research on these topics. We conclude that earlier research may have suffered from the absence of comprehensive gene expression data leading to partial misconceptions about the roles of Wnt genes in development and evolution.
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Affiliation(s)
- Ralf Janssen
- Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, 75236, Uppsala, Sweden.
| | - Matthias Pechmann
- Department of Developmental Biology, Biocenter, Institute for Zoology, University of Cologne, Zuelpicher Str. 47b, 50674, Cologne, Germany
| | - Natascha Turetzek
- Evolutionary Ecology, Faculty of Biology, Ludwig-Maximilians Universität München, Grosshaderner Strasse 2, 82152, Biozentrum, Germany
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8
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Andrikou C, Hejnol A. FGF signaling acts on different levels of mesoderm development within Spiralia. Development 2021; 148:264929. [PMID: 33999997 PMCID: PMC8180254 DOI: 10.1242/dev.196089] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 04/08/2021] [Indexed: 01/23/2023]
Abstract
FGF signaling is involved in mesoderm induction in members of deuterostomes (e.g. tunicates, hemichordates), but not in flies and nematodes, in which it has a role in mesoderm patterning and migration. However, we need comparable studies in other protostome taxa in order to decipher whether this mesoderm-inducing function of FGF extends beyond the lineage of deuterostomes. Here, we investigated the role of FGF signaling in mesoderm development in three species of lophophorates, a clade within the protostome group Spiralia. Our gene expression analyses show that the mesodermal molecular patterning is conserved between brachiopods and phoronids, but the spatial and temporal recruitment of transcription factors differs significantly. Moreover, the use of the inhibitor SU5402 demonstrates that FGF signaling is involved in different steps of mesoderm development, as well as in morphogenetic movements of gastrulation and axial elongation. Our findings suggest that the mesoderm-inducing role of FGF extends beyond the group of deuterostomes.
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Affiliation(s)
- Carmen Andrikou
- University of Bergen, Department of Biological Sciences, Thormøhlensgate 55, 5006 Bergen, Norway.,Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006 Bergen, Norway
| | - Andreas Hejnol
- University of Bergen, Department of Biological Sciences, Thormøhlensgate 55, 5006 Bergen, Norway.,Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006 Bergen, Norway
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9
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Schacht MI, Schomburg C, Bucher G. six3 acts upstream of foxQ2 in labrum and neural development in the spider Parasteatoda tepidariorum. Dev Genes Evol 2020; 230:95-104. [PMID: 32040712 PMCID: PMC7128001 DOI: 10.1007/s00427-020-00654-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Accepted: 01/29/2020] [Indexed: 12/12/2022]
Abstract
Anterior patterning in animals is based on a gene regulatory network, which comprises highly conserved transcription factors like six3, pax6 and otx. More recently, foxQ2 was found to be an ancestral component of this network but its regulatory interactions showed evolutionary differences. In most animals, foxQ2 is a downstream target of six3 and knockdown leads to mild or no epidermal phenotypes. In contrast, in the red flour beetle Tribolium castaneum, foxQ2 gained a more prominent role in patterning leading to strong epidermal and brain phenotypes and being required for six3 expression. However, it has remained unclear which of these novel aspects were insect or arthropod specific. Here, we study expression and RNAi phenotype of the single foxQ2 ortholog of the spider Parasteatoda tepidariorum. We find early anterior expression similar to the one of insects. Further, we show an epidermal phenotype in the labrum similar to the insect phenotype. However, our data indicate that foxQ2 is positioned downstream of six3 like in other animals but unlike insects. Hence, the epidermal and neural pattering function of foxQ2 is ancestral for arthropods while the upstream role of foxQ2 may have evolved in the lineage leading to the insects.
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Affiliation(s)
- Magdalena Ines Schacht
- Department of Evolutionary Developmental Genetics, GZMB, University of Göttingen, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Christoph Schomburg
- Department of Evolutionary Developmental Genetics, GZMB, University of Göttingen, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany
- Institut für Allgemeine Zoologie und Entwicklungsbiologie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 38, 35392, Giessen, Germany
| | - Gregor Bucher
- Department of Evolutionary Developmental Genetics, GZMB, University of Göttingen, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany.
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10
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Annunziata R, Andrikou C, Perillo M, Cuomo C, Arnone MI. Development and evolution of gut structures: from molecules to function. Cell Tissue Res 2019; 377:445-458. [PMID: 31446445 DOI: 10.1007/s00441-019-03093-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 08/09/2019] [Indexed: 12/13/2022]
Abstract
The emergence of a specialized system for food digestion and nutrient absorption was a crucial innovation for multicellular organisms. Digestive systems with different levels of complexity evolved in different animals, with the endoderm-derived one-way gut of most bilaterians to be the prevailing and more specialized form. While the molecular events regulating the early phases of embryonic tissue specification have been deeply investigated in animals occupying different phylogenetic positions, the mechanisms underlying gut patterning and gut-associated structures differentiation are still mostly obscure. In this review, we describe the main discoveries in gut and gut-associated structures development in echinoderm larvae (mainly for sea urchin and, when available, for sea star) and compare them with existing information in vertebrates. An impressive degree of conservation emerges when comparing the transcription factor toolkits recruited for gut cells and tissue differentiation in animals as diverse as echinoderms and vertebrates, thus suggesting that their function emerged in the deuterostome ancestor.
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Affiliation(s)
- Rossella Annunziata
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa comunale, 80121, Naples, Italy
| | - Carmen Andrikou
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa comunale, 80121, Naples, Italy
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006, Bergen, Norway
| | - Margherita Perillo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa comunale, 80121, Naples, Italy
- Department of Molecular and Cell Biology and Biochemistry, Brown University, 185 Meeting St, Providence, RI, 02912, USA
| | - Claudia Cuomo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa comunale, 80121, Naples, Italy
| | - Maria I Arnone
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa comunale, 80121, Naples, Italy.
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11
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Wang D, Vannier J, Schumann I, Wang X, Yang XG, Komiya T, Uesugi K, Sun J, Han J. Origin of ecdysis: fossil evidence from 535-million-year-old scalidophoran worms. Proc Biol Sci 2019; 286:20190791. [PMID: 31288707 DOI: 10.1098/rspb.2019.0791] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
With millions of extant species, ecdysozoans (Scalidophora, Nematoida and Panarthropoda) constitute a major portion of present-day biodiversity. All ecdysozoans secrete an exoskeletal cuticle which must be moulted periodically and replaced by a larger one. Although moulting (ecdysis) has been recognized in early Palaeozoic panarthropods such as trilobites and basal groups such as anomalocaridids and lobopodians, the fossil record lacks clear evidence of ecdysis in early scalidophorans, largely because of difficulties in recognizing true exuviae. Here, we describe two types of exuviae in microscopic scalidophoran worms from the lowermost Cambrian Kuanchuanpu Formation ( ca 535 Ma) of China and reconstruct their moulting process. These basal scalidophorans moulted in a manner similar to that of extant priapulid worms, extricating themselves smoothly from their old tubular cuticle or turning their exuviae inside out like the finger of a glove. This is the oldest record of moulting in ecdysozoans. We also discuss the origin of ecdysis in the light of recent molecular analyses and the significance of moulting in the early evolution of animals.
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Affiliation(s)
- Deng Wang
- 1 State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments, Department of Geology, Northwest University , Xi'an 710069 , People's Republic of China.,2 Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement (CNRS-UMR 5276), Université Claude Bernard Lyon 1 , Villeurbanne Cedex 69622 , France
| | - Jean Vannier
- 2 Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement (CNRS-UMR 5276), Université Claude Bernard Lyon 1 , Villeurbanne Cedex 69622 , France
| | - Isabell Schumann
- 3 Department of Genetics, University of Leipzig , Talstraße 33, 04103 Leipzig , Germany.,4 Molecular Evolution & Animal Systematics, Institute of Biology, University of Leipzig , Talstraße 33, 04103 Leipzig , Germany
| | - Xing Wang
- 5 Qingdao Institute of Marine Geology, China Geological Survey , Qingdao 266071 , People's Republic of China
| | - Xiao-Guang Yang
- 1 State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments, Department of Geology, Northwest University , Xi'an 710069 , People's Republic of China
| | - Tsuyoshi Komiya
- 6 Department of Earth Science and Astronomy, Graduate School of Arts and Sciences, University of Tokyo , Tokyo 153-8902 , Japan
| | - Kentaro Uesugi
- 7 Japan Synchrotron Radiation Research Institute (JASRI) , 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo , Japan
| | - Jie Sun
- 1 State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments, Department of Geology, Northwest University , Xi'an 710069 , People's Republic of China
| | - Jian Han
- 1 State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments, Department of Geology, Northwest University , Xi'an 710069 , People's Republic of China
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12
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Hogvall M, Vellutini BC, Martín-Durán JM, Hejnol A, Budd GE, Janssen R. Embryonic expression of priapulid Wnt genes. Dev Genes Evol 2019; 229:125-135. [PMID: 31273439 PMCID: PMC6647475 DOI: 10.1007/s00427-019-00636-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 06/02/2019] [Indexed: 01/12/2023]
Abstract
Posterior elongation of the developing embryo is a common feature of animal development. One group of genes that is involved in posterior elongation is represented by the Wnt genes, secreted glycoprotein ligands that signal to specific receptors on neighbouring cells and thereby establish cell-to-cell communication. In segmented animals such as annelids and arthropods, Wnt signalling is also likely involved in segment border formation and regionalisation of the segments. Priapulids represent unsegmented worms that are distantly related to arthropods. Despite their interesting phylogenetic position and their importance for the understanding of ecdysozoan evolution, priapulids still represent a highly underinvestigated group of animals. Here, we study the embryonic expression patterns of the complete sets of Wnt genes in the priapulids Priapulus caudatus and Halicryptus spinulosus. We find that both priapulids possess a complete set of 12 Wnt genes. At least in Priapulus, most of these genes are expressed in and around the posterior-located blastopore and thus likely play a role in posterior elongation. Together with previous work on the expression of other genetic factors such as caudal and even-skipped, this suggests that posterior elongation in priapulids is under control of the same (or very similar) conserved gene regulatory network as in arthropods.
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Affiliation(s)
- Mattias Hogvall
- Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, Uppsala, Sweden
| | - Bruno C Vellutini
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006, Bergen, Norway.,Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307, Dresden, Germany
| | - José M Martín-Durán
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006, Bergen, Norway.,School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006, Bergen, Norway
| | - Graham E Budd
- Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, Uppsala, Sweden
| | - Ralf Janssen
- Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, Uppsala, Sweden.
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13
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Nowotschin S, Hadjantonakis AK, Campbell K. The endoderm: a divergent cell lineage with many commonalities. Development 2019; 146:146/11/dev150920. [PMID: 31160415 PMCID: PMC6589075 DOI: 10.1242/dev.150920] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The endoderm is a progenitor tissue that, in humans, gives rise to the majority of internal organs. Over the past few decades, genetic studies have identified many of the upstream signals specifying endoderm identity in different model systems, revealing them to be divergent from invertebrates to vertebrates. However, more recent studies of the cell behaviours driving endodermal morphogenesis have revealed a surprising number of shared features, including cells undergoing epithelial-to-mesenchymal transitions (EMTs), collective cell migration, and mesenchymal-to-epithelial transitions (METs). In this Review, we highlight how cross-organismal studies of endoderm morphogenesis provide a useful perspective that can move our understanding of this fascinating tissue forward.
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Affiliation(s)
- Sonja Nowotschin
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Anna-Katerina Hadjantonakis
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Kyra Campbell
- Bateson Centre, Firth Court, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK .,Department of Biomedical Science, Firth Court, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
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14
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Baenas N, Wagner AE. Drosophila melanogaster as an alternative model organism in nutrigenomics. GENES AND NUTRITION 2019; 14:14. [PMID: 31080523 PMCID: PMC6501408 DOI: 10.1186/s12263-019-0641-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 04/17/2019] [Indexed: 12/12/2022]
Abstract
Nutrigenomics explains the interaction between the genome, the proteome, the epigenome, the metabolome, and the microbiome with the nutritional environment of an organism. It is therefore situated at the interface between an organism's health, its diet, and the genome. The diet and/or specific dietary compounds are able to affect not only the gene expression patterns, but also the epigenetic mechanisms as well as the production of metabolites and the bacterial composition of the microbiota. Drosophila melanogaster provides a well-suited model organism to unravel these interactions in the context of nutrigenomics as it combines several advantages including an affordable maintenance, a short generation time, a high fecundity, a relatively short life expectancy, a well-characterized genome, and the availability of several mutant fly lines. Furthermore, it hosts a mammalian-like intestinal system with a clear microbiota and a fat body resembling the adipose tissue with liver-equivalent oenocytes, supporting the fly as an excellent model organism not only in nutrigenomics but also in nutritional research. Experimental approaches that are essentially needed in nutrigenomic research, including several sequencing technologies, have already been established in the fruit fly. However, studies investigating the interaction of a specific diet and/or dietary compounds in the fly are currently very limited. The present review provides an overview of the fly's morphology including the intestinal microbiome and antimicrobial peptides as modulators of the immune system. Additionally, it summarizes nutrigenomic approaches in the fruit fly helping to elucidate host-genome interactions with the nutritional environment in the model organism Drosophila melanogaster.
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Affiliation(s)
- Nieves Baenas
- 1Institute of Nutritional Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Anika E Wagner
- 2Institute of Nutritional Sciences, Justus-Liebig-University, Wilhelmstrasse 20, 35392 Giessen, Germany
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15
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Nielsen C. Was the ancestral panarthropod mouth ventral or terminal? ARTHROPOD STRUCTURE & DEVELOPMENT 2019; 49:152-154. [PMID: 30445117 DOI: 10.1016/j.asd.2018.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 11/09/2018] [Accepted: 11/09/2018] [Indexed: 06/09/2023]
Abstract
It has recently been suggested that the panarthropod mouth was ancestrally terminal, based on the assumption that the ancestral tardigrade had a terminal mouth and on the observations of a terminal mouth in adults of some stem-group fossils. This is shown to be unlikely, and it is concluded that the ancestral panarthropod had a ventral mouth.
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Affiliation(s)
- Claus Nielsen
- Biosystematics, The Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, Copenhagen, Denmark.
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16
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Ortega-Hernández J, Janssen R, Budd GE. The last common ancestor of Ecdysozoa had an adult terminal mouth. ARTHROPOD STRUCTURE & DEVELOPMENT 2019; 49:155-158. [PMID: 30458236 DOI: 10.1016/j.asd.2018.11.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 11/09/2018] [Indexed: 06/09/2023]
Abstract
The Ecdysozoa is a major animal clade whose main uniting feature is a distinctive growth strategy that requires the periodical moulting of the external cuticle. The staggering diversity within Ecdysozoa has prompted substantial efforts to reconstruct their origin and early evolution. Based on palaentological and developmental data, we proposed a scenario for the early evolution of the ecdysozoan clade Panarthropoda (Onychophora, Tardigrada, Euarthropoda), and postulated that a terminal mouth is ancestral for this lineage. In light of the accompanying comment by Claus Nielsen, we take this opportunity to clarify the significance of our argumentation for Panarthropoda in the phylogenetic context of Ecdysozoa, and Bilateria more broadly. We conclude that the ancestral ecdysozoan most likely had an adult terminal mouth, and that the last common ancestors of all the phyla that constitute Ecdysozoa almost certainly also had an adult terminal mouth. The occurrence of a ventral-facing mouth in various adult ecdysozoans - particularly panarthropods - is the result of convergence. Despite the paucity of embryological data on fossil taxa, we contemplate the likelihood that a developmentally early ventral mouth opening could be ancestral for Ecdysozoa, and if so, then this would represent a symplesiomorphy of Bilateria as a whole.
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Affiliation(s)
- Javier Ortega-Hernández
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK; Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA.
| | - Ralf Janssen
- Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, Uppsala se 752 36, Sweden
| | - Graham E Budd
- Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, Uppsala se 752 36, Sweden
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17
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Kawaguchi M, Sugiyama K, Matsubara K, Lin CY, Kuraku S, Hashimoto S, Suwa Y, Yong LW, Takino K, Higashida S, Kawamura D, Yu JK, Seki Y. Co-option of the PRDM14–CBFA2T complex from motor neurons to pluripotent cells during vertebrate evolution. Development 2019; 146:dev.168633. [DOI: 10.1242/dev.168633] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 12/20/2018] [Indexed: 11/20/2022]
Abstract
Gene regulatory networks underlying cellular pluripotency are controlled by a core circuitry of transcription factors in mammals, including POU5F1. However, the evolutionary origin and transformation of pluripotency-related transcriptional networks have not been elucidated in deuterostomes. PR domain-containing protein 14 (PRDM14) is specifically expressed in pluripotent cells and germ cells, and required for establishing embryonic stem cells (ESCs) and primordial germ cells in mice. Here, we compared the functions and expression patterns of PRDM14 orthologues within deuterostomes. Amphioxus PRDM14 and zebrafish PRDM14, but not sea urchin PRDM14, compensated for mouse PRDM14 function in maintaining mouse ESC pluripotency. Interestingly, sea urchin PRDM14 together with sea urchin CBFA2T, an essential partner of PRDM14 in mouse ESCs, complemented the self-renewal defect in mouse Prdm14 KO ESCs. Contrary to the Prdm14-expression pattern in mouse embryos, Prdm14 was expressed in motor neurons of amphioxus embryos as observed in zebrafish embryos. Thus, Prdm14 expression in motor neurons was conserved in non-tetrapod deuterostomes and the co-option of the PRDM14-CBFA2T complex from motor neurons into pluripotent cells may have maintained the transcriptional network for pluripotency during vertebrate evolution.
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Affiliation(s)
- Masanori Kawaguchi
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin Univerisity, Japan
| | - Kota Sugiyama
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin Univerisity, Japan
| | - Kazumi Matsubara
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin Univerisity, Japan
| | - Che-Yi Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Shigehiro Kuraku
- Laboratory for Phyloinformatics, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minami, Kobe, 650-0047, Japan
| | - Shota Hashimoto
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin Univerisity, Japan
| | - Yoshiaki Suwa
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin Univerisity, Japan
| | - Luok Wen Yong
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Koji Takino
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin Univerisity, Japan
| | - Shota Higashida
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin Univerisity, Japan
| | - Daisuke Kawamura
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin Univerisity, Japan
| | - Jr-Kai Yu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Yoshiyuki Seki
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin Univerisity, Japan
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18
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Ramos-Vicente D, Ji J, Gratacòs-Batlle E, Gou G, Reig-Viader R, Luís J, Burguera D, Navas-Perez E, García-Fernández J, Fuentes-Prior P, Escriva H, Roher N, Soto D, Bayés À. Metazoan evolution of glutamate receptors reveals unreported phylogenetic groups and divergent lineage-specific events. eLife 2018; 7:e35774. [PMID: 30465522 PMCID: PMC6307864 DOI: 10.7554/elife.35774] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 11/20/2018] [Indexed: 01/28/2023] Open
Abstract
Glutamate receptors are divided in two unrelated families: ionotropic (iGluR), driving synaptic transmission, and metabotropic (mGluR), which modulate synaptic strength. The present classification of GluRs is based on vertebrate proteins and has remained unchanged for over two decades. Here we report an exhaustive phylogenetic study of GluRs in metazoans. Importantly, we demonstrate that GluRs have followed different evolutionary histories in separated animal lineages. Our analysis reveals that the present organization of iGluRs into six classes does not capture the full complexity of their evolution. Instead, we propose an organization into four subfamilies and ten classes, four of which have never been previously described. Furthermore, we report a sister class to mGluR classes I-III, class IV. We show that many unreported proteins are expressed in the nervous system, and that new Epsilon receptors form functional ligand-gated ion channels. We propose an updated classification of glutamate receptors that includes our findings.
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Affiliation(s)
- David Ramos-Vicente
- Molecular Physiology of the Synapse LaboratoryBiomedical Research Institute Sant PauBarcelonaSpain
- Universitat Autònoma de BarcelonaBarcelonaSpain
| | - Jie Ji
- Institute of Biotechnology and Biomedicine, Department of Cell Biology, Animal Physiology and ImmunologyUniversitat Autònoma de BarcelonaBarcelonaSpain
| | - Esther Gratacòs-Batlle
- Neurophysiology Laboratory, Department of Biomedicine, Medical School, August Pi i Sunyer Biomedical Research Institute, Institute of NeurosciencesUniversitat de BarcelonaBarcelonaSpain
| | - Gemma Gou
- Molecular Physiology of the Synapse LaboratoryBiomedical Research Institute Sant PauBarcelonaSpain
- Universitat Autònoma de BarcelonaBarcelonaSpain
| | - Rita Reig-Viader
- Molecular Physiology of the Synapse LaboratoryBiomedical Research Institute Sant PauBarcelonaSpain
- Universitat Autònoma de BarcelonaBarcelonaSpain
| | - Javier Luís
- Molecular Physiology of the Synapse LaboratoryBiomedical Research Institute Sant PauBarcelonaSpain
- Universitat Autònoma de BarcelonaBarcelonaSpain
| | - Demian Burguera
- Department of Genetics, School of Biology, Institut de BiomedicinaUniversity of BarcelonaBarcelonaSpain
| | - Enrique Navas-Perez
- Department of Genetics, School of Biology, Institut de BiomedicinaUniversity of BarcelonaBarcelonaSpain
| | - Jordi García-Fernández
- Department of Genetics, School of Biology, Institut de BiomedicinaUniversity of BarcelonaBarcelonaSpain
| | - Pablo Fuentes-Prior
- Molecular Bases of DiseaseBiomedical Research Institute Sant Pau, Hospital de la Santa Creu i Sant PauBarcelonaSpain
| | - Hector Escriva
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes MarinsBanyuls-sur-MerFrance
| | - Nerea Roher
- Institute of Biotechnology and Biomedicine, Department of Cell Biology, Animal Physiology and ImmunologyUniversitat Autònoma de BarcelonaBarcelonaSpain
| | - David Soto
- Neurophysiology Laboratory, Department of Biomedicine, Medical School, August Pi i Sunyer Biomedical Research Institute, Institute of NeurosciencesUniversitat de BarcelonaBarcelonaSpain
| | - Àlex Bayés
- Molecular Physiology of the Synapse LaboratoryBiomedical Research Institute Sant PauBarcelonaSpain
- Universitat Autònoma de BarcelonaBarcelonaSpain
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19
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Evolution of the bilaterian mouth and anus. Nat Ecol Evol 2018; 2:1358-1376. [PMID: 30135501 DOI: 10.1038/s41559-018-0641-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 06/26/2018] [Accepted: 07/11/2018] [Indexed: 12/17/2022]
Abstract
It is widely held that the bilaterian tubular gut with mouth and anus evolved from a simple gut with one major gastric opening. However, there is no consensus on how this happened. Did the single gastric opening evolve into a mouth, with the anus forming elsewhere in the body (protostomy), or did it evolve into an anus, with the mouth forming elsewhere (deuterostomy), or did it evolve into both mouth and anus (amphistomy)? These questions are addressed by the comparison of developmental fates of the blastopore, the opening of the embryonic gut, in diverse animals that live today. Here we review comparative data on the identity and fate of blastoporal tissue, investigate how the formation of the through-gut relates to the major body axes, and discuss to what extent evolutionary scenarios are consistent with these data. Available evidence indicates that stem bilaterians had a slit-like gastric opening that was partially closed in subsequent evolution, leaving open the anus and most likely also the mouth, which would favour amphistomy. We discuss remaining difficulties, and outline directions for future research.
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20
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Sinigaglia C, Thiel D, Hejnol A, Houliston E, Leclère L. A safer, urea-based in situ hybridization method improves detection of gene expression in diverse animal species. Dev Biol 2017; 434:15-23. [PMID: 29197505 DOI: 10.1016/j.ydbio.2017.11.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 11/20/2017] [Accepted: 11/27/2017] [Indexed: 01/27/2023]
Abstract
In situ hybridization is a widely employed technique allowing spatial visualization of gene expression in fixed specimens. It has greatly advanced our understanding of biological processes, including developmental regulation. In situ protocols are today routinely followed in numerous laboratories, and although details might change, they all include a hybridization step, where specific antisense RNA or DNA probes anneal to the target nucleic acid sequence. This step is generally carried out at high temperatures and in a denaturing solution, called hybridization buffer, commonly containing 50% (v/v) formamide - a hazardous chemical. When applied to the soft-bodied hydrozoan medusa Clytia hemisphaerica, we found that this traditional hybridization approach was not fully satisfactory, causing extensive deterioration of morphology and tissue texture which compromised our observation and interpretation of results. We thus tested alternative solutions for in situ detection of gene expression and, inspired by optimized protocols for Northern and Southern blot analysis, we substituted the 50% formamide with an equal volume of 8M urea solution in the hybridization buffer. Our new protocol not only yielded better morphologies and tissue consistency, but also notably improved the resolution of the signal, allowing more precise localization of gene expression and reducing aspecific staining associated with problematic areas. Given the improved results and reduced manipulation risks, we tested the urea protocol on other metazoans, two brachiopod species (Novocrania anomala and Terebratalia transversa) and the priapulid worm Priapulus caudatus, obtaining a similar reduction of aspecific probe binding. Overall, substitution of formamide by urea during in situ hybridization offers a safer alternative, potentially of widespread use in research, medical and teaching contexts. We encourage other workers to test this approach on their study organisms, and hope that they will also obtain better sample preservation, more precise expression patterns and fewer problems due to aspecific staining, as we report here for Clytia medusae and Novocrania and Terebratalia developing larvae.
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Affiliation(s)
- Chiara Sinigaglia
- Sorbonne Universités, UPMC Univ. Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), 06230 Villefranche-sur-mer, France.
| | - Daniel Thiel
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006 Bergen, Norway
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006 Bergen, Norway
| | - Evelyn Houliston
- Sorbonne Universités, UPMC Univ. Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), 06230 Villefranche-sur-mer, France
| | - Lucas Leclère
- Sorbonne Universités, UPMC Univ. Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), 06230 Villefranche-sur-mer, France
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21
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Martín-Durán JM, Vellutini BC, Hejnol A. Embryonic chirality and the evolution of spiralian left-right asymmetries. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0411. [PMID: 27821523 PMCID: PMC5104510 DOI: 10.1098/rstb.2015.0411] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2016] [Indexed: 01/09/2023] Open
Abstract
The group Spiralia includes species with one of the most significant cases of left–right asymmetries in animals: the coiling of the shell of gastropod molluscs (snails). In this animal group, an early event of embryonic chirality controlled by cytoskeleton dynamics and the subsequent differential activation of the genes nodal and Pitx determine the left–right axis of snails, and thus the direction of coiling of the shell. Despite progressive advances in our understanding of left–right axis specification in molluscs, little is known about left–right development in other spiralian taxa. Here, we identify and characterize the expression of nodal and Pitx orthologues in three different spiralian animals—the brachiopod Novocrania anomala, the annelid Owenia fusiformis and the nemertean Lineus ruber—and demonstrate embryonic chirality in the biradial-cleaving spiralian embryo of the bryozoan Membranipora membranacea. We show asymmetric expression of nodal and Pitx in the brachiopod and annelid, respectively, and symmetric expression of Pitx in the nemertean. Our findings indicate that early embryonic chirality is widespread and independent of the cleavage programme in the Spiralia. Additionally, our study illuminates the evolution of nodal and Pitx signalling by demonstrating embryonic asymmetric expression in lineages without obvious adult left–right asymmetries. This article is part of the themed issue ‘Provocative questions in left–right asymmetry’.
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Affiliation(s)
- José M Martín-Durán
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, Bergen, 5006, Norway
| | - Bruno C Vellutini
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, Bergen, 5006, Norway
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, Bergen, 5006, Norway
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22
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Giribet G, Edgecombe GD. Current Understanding of Ecdysozoa and its Internal Phylogenetic Relationships. Integr Comp Biol 2017; 57:455-466. [DOI: 10.1093/icb/icx072] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Janssen R, Budd GE. Investigation of endoderm marker-genes during gastrulation and gut-development in the velvet worm Euperipatoides kanangrensis. Dev Biol 2017; 427:155-164. [DOI: 10.1016/j.ydbio.2017.04.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 04/14/2017] [Accepted: 04/23/2017] [Indexed: 11/30/2022]
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24
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Janssen R. A molecular view of onychophoran segmentation. ARTHROPOD STRUCTURE & DEVELOPMENT 2017; 46:341-353. [PMID: 27725255 DOI: 10.1016/j.asd.2016.10.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/22/2016] [Accepted: 10/03/2016] [Indexed: 06/06/2023]
Abstract
This paper summarizes our current knowledge on the expression and assumed function of Drosophila and (other) arthropod segmentation gene orthologs in Onychophora, a closely related outgroup to Arthropoda. This includes orthologs of the so-called Drosophila segmentation gene cascade including the Hox genes, as well as other genetic factors and pathways involved in non-drosophilid arthropods. Open questions about and around the topic are addressed, such as the definition of segments in onychophorans, the unclear regulation of conserved expression patterns downstream of non-conserved factors, and the potential role of mesodermal patterning in onychophoran segmentation.
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Affiliation(s)
- Ralf Janssen
- Uppsala University, Department of Earth Sciences, Palaeobiology, Villavägen 16, 75236 Uppsala, Sweden.
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25
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Vellutini BC, Martín-Durán JM, Hejnol A. Cleavage modification did not alter blastomere fates during bryozoan evolution. BMC Biol 2017; 15:33. [PMID: 28454545 PMCID: PMC5408385 DOI: 10.1186/s12915-017-0371-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 04/04/2017] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Stereotypic cleavage patterns play a crucial role in cell fate determination by precisely positioning early embryonic blastomeres. Although misplaced cell divisions can alter blastomere fates and cause embryonic defects, cleavage patterns have been modified several times during animal evolution. However, it remains unclear how evolutionary changes in cleavage impact the specification of blastomere fates. Here, we analyze the transition from spiral cleavage - a stereotypic pattern remarkably conserved in many protostomes - to a biradial cleavage pattern, which occurred during the evolution of bryozoans. RESULTS Using 3D-live imaging time-lapse microscopy (4D-microscopy), we characterize the cell lineage, MAPK signaling, and the expression of 16 developmental genes in the bryozoan Membranipora membranacea. We found that the molecular identity and the fates of early bryozoan blastomeres are similar to the putative homologous blastomeres in spiral-cleaving embryos. CONCLUSIONS Our work suggests that bryozoans have retained traits of spiral development, such as the early embryonic fate map, despite the evolution of a novel cleavage geometry. These findings provide additional support that stereotypic cleavage patterns can be modified during evolution without major changes to the molecular identity and fate of embryonic blastomeres.
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Affiliation(s)
- Bruno C Vellutini
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006, Bergen, Norway
| | - José M Martín-Durán
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006, Bergen, Norway
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006, Bergen, Norway.
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26
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Feitosa NM, Pechmann M, Schwager EE, Tobias-Santos V, McGregor AP, Damen WGM, Nunes da Fonseca R. Molecular control of gut formation in the spider Parasteatoda tepidariorum. Genesis 2017; 55. [PMID: 28432834 DOI: 10.1002/dvg.23033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 02/23/2017] [Accepted: 03/16/2017] [Indexed: 12/16/2022]
Abstract
The development of a digestive system is an essential feature of bilaterians. Studies of the molecular control of gut formation in arthropods have been studied in detail in the fruit fly Drosophila melanogaster. However, little is known in other arthropods, especially in noninsect arthropods. To better understand the evolution of arthropod alimentary system, we investigate the molecular control of gut development in the spider Parasteatoda tepidariorum (Pt), the primary chelicerate model species for developmental studies. Orthologs of the ectodermal genes Pt-wingless (Pt-wg) and Pt-hedgehog (Pt-hh), of the endodermal genes, Pt-serpent (Pt-srp) and Pt-hepatocyte-nuclear factor-4 (Pt-hnf4) and of the mesodermal gene Pt-twist (Pt-twi) are expressed in the same germ layers during spider gut development as in D. melanogaster. Thus, our expression data suggest that the downstream molecular components involved in gut development in arthropods are conserved. However, Pt-forkhead (Pt-fkh) expression and function in spiders is considerably different from its D. melanogaster ortholog. Pt-fkh is expressed before gastrulation in a cell population that gives rise to endodermal and mesodermal precursors, suggesting a possible role for this factor in specification of both germ layers. To test this hypothesis, we knocked down Pt-fkh via RNA interference. Pt-fkh RNAi embryos not only fail to develop a proper gut, but also lack the mesodermal Pt-twi expressing cells. Thus, in spiders Pt-fkh specifies endodermal and mesodermal germ layers. We discuss the implications of these findings for the evolution and development of gut formation in Ecdysozoans.
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Affiliation(s)
- Natália Martins Feitosa
- Laboratório Integrado de Ciências Morfofuncionais, Núcleo em Ecologia e Desenvolvimento Socio-Ambiental de Macaé (NUPEM), Campus Macaé, Universidade Federal do Rio de Janeiro (UFRJ), Macaé, Rio de Janeiro, 27920-560, Brazil
| | - Matthias Pechmann
- Institute for Developmental Biology, University of Cologne, Cologne, North-Rhine Westphalia, 50674, Germany
| | - Evelyn E Schwager
- Department of Biological Sciences, University of Massachusetts Lowell, 198 Riverside Street, Lowell, Massachusetts, 01854
| | - Vitória Tobias-Santos
- Laboratório Integrado de Ciências Morfofuncionais, Núcleo em Ecologia e Desenvolvimento Socio-Ambiental de Macaé (NUPEM), Campus Macaé, Universidade Federal do Rio de Janeiro (UFRJ), Macaé, Rio de Janeiro, 27920-560, Brazil
| | - Alistair P McGregor
- Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford, OX3 0BP, United Kingdom
| | - Wim G M Damen
- Department of Genetics, Friedrich-Schiller-Universität Jena, Philosophenweg 12, Jena, 07743, Germany
| | - Rodrigo Nunes da Fonseca
- Laboratório Integrado de Ciências Morfofuncionais, Núcleo em Ecologia e Desenvolvimento Socio-Ambiental de Macaé (NUPEM), Campus Macaé, Universidade Federal do Rio de Janeiro (UFRJ), Macaé, Rio de Janeiro, 27920-560, Brazil.,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular (INCT-EM), Universidade Federal do Rio de Janeiro (UFRJ), 21941-599 Rio de Janeiro, Rio de Janeiro, Brazil
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Redl E, Scherholz M, Wollesen T, Todt C, Wanninger A. Cell Proliferation Pattern and Twist Expression in an Aplacophoran Mollusk Argue Against Segmented Ancestry of Mollusca. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2016; 326:422-436. [PMID: 27966274 PMCID: PMC5299467 DOI: 10.1002/jez.b.22714] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 10/28/2016] [Accepted: 11/02/2016] [Indexed: 01/12/2023]
Abstract
The study of aplacophoran mollusks (i.e., Solenogastres or Neomeniomorpha and Caudofoveata or Chaetodermomorpha) has traditionally been regarded as crucial for reconstructing the morphology of the last common ancestor of the Mollusca. Since their proposed close relatives, the Polyplacophora, show a distinct seriality in certain organ systems, the aplacophorans are also in the focus of attention with regard to the question of a potential segmented ancestry of mollusks. To contribute to this question, we investigated cell proliferation patterns and the expression of the twist ortholog during larval development in solenogasters. In advanced to late larvae, during the outgrowth of the trunk, a pair of longitudinal bands of proliferating cells is found subepithelially in a lateral to ventrolateral position. These bands elongate during subsequent development as the trunk grows longer. Likewise, expression of twist occurs in two laterally positioned, subepithelial longitudinal stripes in advanced larvae. Both, the pattern of proliferating cells and the expression domain of twist demonstrate the existence of extensive and long‐lived mesodermal bands in a worm‐shaped aculiferan, a situation which is similar to annelids but in stark contrast to conchiferans, where the mesodermal bands are usually rudimentary and ephemeral. Yet, in contrast to annelids, neither the bands of proliferating cells nor the twist expression domain show a separation into distinct serial subunits, which clearly argues against a segmented ancestry of mollusks. Furthermore, the lack of twist expression during the development of the ventromedian muscle argues against homology of a ventromedian longitudinal muscle in protostomes with the notochord of chordates.
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Affiliation(s)
- Emanuel Redl
- Faculty of Life Sciences, Department of Integrative Zoology, University of Vienna, Vienna, Austria
| | - Maik Scherholz
- Faculty of Life Sciences, Department of Integrative Zoology, University of Vienna, Vienna, Austria
| | - Tim Wollesen
- Faculty of Life Sciences, Department of Integrative Zoology, University of Vienna, Vienna, Austria
| | - Christiane Todt
- University Museum, The Natural History Collections, University of Bergen, Bergen, Norway
| | - Andreas Wanninger
- Faculty of Life Sciences, Department of Integrative Zoology, University of Vienna, Vienna, Austria
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Brunet T, Fischer AH, Steinmetz PR, Lauri A, Bertucci P, Arendt D. The evolutionary origin of bilaterian smooth and striated myocytes. eLife 2016; 5. [PMID: 27906129 PMCID: PMC5167519 DOI: 10.7554/elife.19607] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 12/01/2016] [Indexed: 12/25/2022] Open
Abstract
The dichotomy between smooth and striated myocytes is fundamental for bilaterian musculature, but its evolutionary origin is unsolved. In particular, interrelationships of visceral smooth muscles remain unclear. Absent in fly and nematode, they have not yet been characterized molecularly outside vertebrates. Here, we characterize expression profile, ultrastructure, contractility and innervation of the musculature in the marine annelid Platynereis dumerilii and identify smooth muscles around the midgut, hindgut and heart that resemble their vertebrate counterparts in molecular fingerprint, contraction speed and nervous control. Our data suggest that both visceral smooth and somatic striated myocytes were present in the protostome-deuterostome ancestor and that smooth myocytes later co-opted the striated contractile module repeatedly – for example, in vertebrate heart evolution. During these smooth-to-striated myocyte conversions, the core regulatory complex of transcription factors conveying myocyte identity remained unchanged, reflecting a general principle in cell type evolution. DOI:http://dx.doi.org/10.7554/eLife.19607.001
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Affiliation(s)
- Thibaut Brunet
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Antje Hl Fischer
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Patrick Rh Steinmetz
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Antonella Lauri
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Paola Bertucci
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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29
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Martín-Durán JM, Wolff GH, Strausfeld NJ, Hejnol A. The larval nervous system of the penis worm Priapulus caudatus (Ecdysozoa). Philos Trans R Soc Lond B Biol Sci 2016; 371:20150050. [PMID: 26598729 PMCID: PMC4685585 DOI: 10.1098/rstb.2015.0050] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The origin and extreme diversification of the animal nervous system is a central question in biology. While most of the attention has traditionally been paid to those lineages with highly elaborated nervous systems (e.g. arthropods, vertebrates, annelids), only the study of the vast animal diversity can deliver a comprehensive view of the evolutionary history of this organ system. In this regard, the phylogenetic position and apparently conservative molecular, morphological and embryological features of priapulid worms (Priapulida) place this animal lineage as a key to understanding the evolution of the Ecdysozoa (i.e. arthropods and nematodes). In this study, we characterize the nervous system of the hatching larva and first lorica larva of the priapulid worm Priapulus caudatus by immunolabelling against acetylated and tyrosinated tubulin, pCaMKII, serotonin and FMRFamide. Our results show that a circumoral brain and an unpaired ventral nerve with a caudal ganglion characterize the central nervous system of hatching embryos. After the first moult, the larva attains some adult features: a neck ganglion, an introvert plexus, and conspicuous secondary longitudinal neurites. Our study delivers a neuroanatomical framework for future embryological studies in priapulid worms, and helps illuminate the course of nervous system evolution in the Ecdysozoa.
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Affiliation(s)
- José M Martín-Durán
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, Bergen 5008, Norway
| | - Gabriella H Wolff
- Department of Neuroscience, School of Mind, Brain, and Behavior, University of Arizona, Tucson, AZ 85721, USA
| | - Nicholas J Strausfeld
- Department of Neuroscience, School of Mind, Brain, and Behavior, University of Arizona, Tucson, AZ 85721, USA Center for Insect Science, University of Arizona, Tucson, AZ 85721, USA
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, Bergen 5008, Norway
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Kerbl A, Martín-Durán JM, Worsaae K, Hejnol A. Molecular regionalization in the compact brain of the meiofaunal annelid Dinophilus gyrociliatus (Dinophilidae). EvoDevo 2016; 7:20. [PMID: 27583125 PMCID: PMC5006589 DOI: 10.1186/s13227-016-0058-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 08/17/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Annelida is a morphologically diverse animal group that exhibits a remarkable variety in nervous system architecture (e.g., number and location of longitudinal cords, architecture of the brain). Despite this heterogeneity of neural arrangements, the molecular profiles related to central nervous system patterning seem to be conserved even between distantly related annelids. In particular, comparative molecular studies on brain and anterior neural region patterning genes have focused so far mainly on indirect-developing macrofaunal taxa. Therefore, analyses on microscopic, direct-developing annelids are important to attain a general picture of the evolutionary events underlying the vast diversity of annelid neuroanatomy. RESULTS We have analyzed the expression domains of 11 evolutionarily conserved genes involved in brain and anterior neural patterning in adult females of the direct-developing meiofaunal annelid Dinophilus gyrociliatus. The small, compact brain shows expression of dimmed, foxg, goosecoid, homeobrain, nk2.1, orthodenticle, orthopedia, pax6, six3/6 and synaptotagmin-1. Although most of the studied markers localize to specific brain areas, the genes six3/6 and synaptotagmin-1 are expressed in nearly all perikarya of the brain. All genes except for goosecoid, pax6 and nk2.2 overlap in the anterior brain region, while the respective expression domains are more separated in the posterior brain. CONCLUSIONS Our findings reveal that the expression patterns of the genes foxg, orthodenticle, orthopedia and six3/6 correlate with those described in Platynereis dumerilii larvae, and homeobrain, nk2.1, orthodenticle and synaptotagmin-1 resemble the pattern of late larvae of Capitella teleta. Although data on other annelids are limited, molecular similarities between adult Dinophilus and larval Platynereis and Capitella suggest an overall conservation of molecular mechanisms patterning the anterior neural regions, independent from developmental and ecological strategies, or of the size and configuration of the nervous system.
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Affiliation(s)
- Alexandra Kerbl
- Marine Biology Section, Department of Biology, Faculty of Science, University of Copenhagen, Universitetsparken 4, 2100 Copenhagen, Denmark
| | - José M Martín-Durán
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate, 55, 5006 Bergen, Norway
| | - Katrine Worsaae
- Marine Biology Section, Department of Biology, Faculty of Science, University of Copenhagen, Universitetsparken 4, 2100 Copenhagen, Denmark
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate, 55, 5006 Bergen, Norway
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31
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Hejnol A, Lowe CJ. Embracing the comparative approach: how robust phylogenies and broader developmental sampling impacts the understanding of nervous system evolution. Philos Trans R Soc Lond B Biol Sci 2015; 370:20150045. [PMID: 26554039 PMCID: PMC4650123 DOI: 10.1098/rstb.2015.0045] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/24/2015] [Indexed: 12/14/2022] Open
Abstract
Molecular biology has provided a rich dataset to develop hypotheses of nervous system evolution. The startling patterning similarities between distantly related animals during the development of their central nervous system (CNS) have resulted in the hypothesis that a CNS with a single centralized medullary cord and a partitioned brain is homologous across bilaterians. However, the ability to precisely reconstruct ancestral neural architectures from molecular genetic information requires that these gene networks specifically map with particular neural anatomies. A growing body of literature representing the development of a wider range of metazoan neural architectures demonstrates that patterning gene network complexity is maintained in animals with more modest levels of neural complexity. Furthermore, a robust phylogenetic framework that provides the basis for testing the congruence of these homology hypotheses has been lacking since the advent of the field of 'evo-devo'. Recent progress in molecular phylogenetics is refining the necessary framework to test previous homology statements that span large evolutionary distances. In this review, we describe recent advances in animal phylogeny and exemplify for two neural characters-the partitioned brain of arthropods and the ventral centralized nerve cords of annelids-a test for congruence using this framework. The sequential sister taxa at the base of Ecdysozoa and Spiralia comprise small, interstitial groups. This topology is not consistent with the hypothesis of homology of tripartitioned brain of arthropods and vertebrates as well as the ventral arthropod and rope-like ladder nervous system of annelids. There can be exquisite conservation of gene regulatory networks between distantly related groups with contrasting levels of nervous system centralization and complexity. Consequently, the utility of molecular characters to reconstruct ancestral neural organization in deep time is limited.
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Affiliation(s)
- Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, Bergen 5008, Norway
| | - Christopher J Lowe
- Hopkins Marine Station, Department of Biology, Stanford University, 120 Oceanview Blvd., Pacific Grove, CA 93950, USA
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32
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Nielsen C. Evolution of deuterostomy - and origin of the chordates. Biol Rev Camb Philos Soc 2015; 92:316-325. [PMID: 26486096 DOI: 10.1111/brv.12229] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 09/15/2015] [Accepted: 09/17/2015] [Indexed: 11/30/2022]
Abstract
The chordates are usually characterized as bilaterians showing deuterostomy, i.e. the mouth developing as a new opening between the archenteron and the ectoderm, serial gill pores/slits, and the complex of chorda and neural tube. Both numerous molecular studies and studies of morphology and embryology demonstrate that the neural tube must be considered homologous to the ventral nerve cord(s) of the protostomes, but the origin of the 'new' mouth of the deuterostomes has remained enigmatic. However, deuterostomy is known to occur in several protostomian groups, such as the chaetognaths and representatives of annelids, molluscs, arthropods and priapulans. This raises the question whether the deuterostomian mouth is in fact homologous with that of the protostomes, viz. the anterior opening of the ancestral blastopore divided through lateral blastopore fusion, i.e. amphistomy. A few studies of gene expression show identical expression patterns around mouth and anus in protostomes and deuterostomes. Closer studies of the embryology of ascidians and vertebrates show that the mouth/stomodaeum differentiates from the anterior edge of the neural plate. Together this indicates that the chordate mouth has moved to the anterior edge of the blastopore, so that the anterior loop of the ancestral circumblastoporal nerve cord, which is narrow in the protostomes, has become indistinguishable. In the vertebrates, the mouth has moved further around the anterior pole to the 'ventral' side. The conclusion must be that the chordate mouth (and that of the deuterostomes in general) is homologous to the protostomian mouth and that the latest common ancestor of protostomes and deuterostomes developed through amphistomy, as suggested by the trochaea theory.
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Affiliation(s)
- Claus Nielsen
- The Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark
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Martín-Durán JM, Vellutini BC, Hejnol A. Evolution and development of the adelphophagic, intracapsular Schmidt's larva of the nemertean Lineus ruber. EvoDevo 2015; 6:28. [PMID: 26417429 PMCID: PMC4584431 DOI: 10.1186/s13227-015-0023-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 09/14/2015] [Indexed: 11/22/2022] Open
Abstract
Background The life cycle of many animals includes a larval stage, which has diversified into an astonishing variety of ecological strategies. The Nemertea is a group of spiralians that exhibits a broad diversity of larval forms, including the iconic pilidium. A pelagic planktotrophic pilidium is the ancestral form in the Pilidiophora, but several lineages exhibit deviations of this condition, mostly as a transition to pelagic lecithotrophy. The most extreme case occurs, however, in the Pilidiophoran Lineus ruber, which exhibits an adelphophagic intracapsular pilidium, the so-called Schmidt’s larva. Results We combined confocal laser scanning microscopy and gene expression studies to characterize the development and metamorphosis of the Schmidt’s larva of L. ruber. The larva forms after gastrulation, and comprises a thin epidermis, a proboscis rudiment and two pairs of imaginal discs from which the juvenile will develop. The cells internalized during gastrulation form a blind gut and the blastopore gives rise to the mouth of the larva and juvenile. The Schmidt’s larva eats other siblings that occupy the same egg capsule, accumulating nutrients for the juvenile. A gradual metamorphosis involves the differentiation of the juvenile cell types from the imaginal discs and the shedding of the larval epidermis. The expression of evolutionarily conserved anterior (foxQ2, six3/6, gsc, otx), endomesodermal (foxA, GATA456-a, twi-a) and posterior (evx, cdx) markers demonstrate that the juvenile retains the molecular patterning of the Schmidt’s larva. After metamorphosis, the juveniles stay over 20 days within the egg masses, until they are fully mature and hatch. Conclusions The evolution of the intracapsular Schmidt’s larva involved the loss of the typical feeding structures of the planktotrophic pilidium and a precocious formation of the imaginal discs, as also observed in other pelagic lecithotrophic forms. However, no special adaptations are observed related to adelphophagy. As in planktotrophic pilidium, the molecular mechanism patterning the juvenile is only active in the imaginal discs and not during the early development of the larva, suggesting two separate molecular programs during nemertean embryogenesis. Our results illuminate the diversification of larval forms in the Pilidiophora and Nemertea, and thus on the developmental mechanisms underlying metazoan larval evolution. Electronic supplementary material The online version of this article (doi:10.1186/s13227-015-0023-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- José M Martín-Durán
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway
| | - Bruno C Vellutini
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway
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Brunet T, Lauri A, Arendt D. Did the notochord evolve from an ancient axial muscle? The axochord hypothesis. Bioessays 2015; 37:836-50. [PMID: 26172338 PMCID: PMC5054868 DOI: 10.1002/bies.201500027] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 06/03/2015] [Accepted: 06/05/2015] [Indexed: 12/20/2022]
Abstract
The origin of the notochord is one of the key remaining mysteries of our evolutionary ancestry. Here, we present a multi‐level comparison of the chordate notochord to the axochord, a paired axial muscle spanning the ventral midline of annelid worms and other invertebrates. At the cellular level, comparative molecular profiling in the marine annelids P. dumerilii and C. teleta reveals expression of similar, specific gene sets in presumptive axochordal and notochordal cells. These cells also occupy corresponding positions in a conserved anatomical topology and undergo similar morphogenetic movements. At the organ level, a detailed comparison of bilaterian musculatures reveals that most phyla form axochord‐like muscles, suggesting that such a muscle was already present in urbilaterian ancestors. Integrating comparative evidence at the cell and organ level, we propose that the notochord evolved by modification of a ventromedian muscle followed by the assembly of an axial complex supporting swimming in vertebrate ancestors.
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Affiliation(s)
- Thibaut Brunet
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Antonella Lauri
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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