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Brunet T. Cell contractility in early animal evolution. Curr Biol 2023; 33:R966-R985. [PMID: 37751712 DOI: 10.1016/j.cub.2023.07.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
Abstract
Tissue deformation mediated by collective cell contractility is a signature characteristic of animals. In most animals, fast and reversible contractions of muscle cells mediate behavior, while slow and irreversible contractions of epithelial or mesenchymal cells play a key role in morphogenesis. Animal tissue contractility relies on the activity of the actin/myosin II complex (together referred to as 'actomyosin'), an ancient and versatile molecular machinery that performs a broad range of functions in development and physiology. This review synthesizes emerging insights from morphological and molecular studies into the evolutionary history of animal contractile tissue. The most ancient functions of actomyosin are cell crawling and cytokinesis, which are found in a wide variety of unicellular eukaryotes and in individual metazoan cells. Another contractile functional module, apical constriction, is universal in metazoans and shared with choanoflagellates, their closest known living relatives. The evolution of animal contractile tissue involved two key innovations: firstly, the ability to coordinate and integrate actomyosin assembly across multiple cells, notably to generate supracellular cables, which ensure tissue integrity but also allow coordinated morphogenesis and movements at the organism scale; and secondly, the evolution of dedicated contractile cell types for adult movement, belonging to two broad categories respectively defined by the expression of the fast (striated-type) and slow (smooth/non-muscle-type) myosin II paralogs. Both contractile cell types ancestrally resembled generic contractile epithelial or mesenchymal cells and might have played a versatile role in both behavior and morphogenesis. Modern animal contractile cells span a continuum between unspecialized contractile epithelia (which underlie behavior in modern placozoans), epithelia with supracellular actomyosin cables (found in modern sponges), epitheliomuscular tissues (with a concentration of actomyosin cables in basal processes, for example in sea anemones), and specialized muscle tissue that has lost most or all epithelial properties (as in ctenophores, jellyfish and bilaterians). Recent studies in a broad range of metazoans have begun to reveal the molecular basis of these transitions, powered by the elaboration of the contractile apparatus and the evolution of 'core regulatory complexes' of transcription factors specifying contractile cell identity.
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Affiliation(s)
- Thibaut Brunet
- Institut Pasteur, Université Paris-Cité, CNRS UMR3691, Evolutionary Cell Biology and Evolution of Morphogenesis Unit, 25-28 Rue du Docteur Roux, 75015 Paris, France.
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2
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Cole AG, Jahnel SM, Kaul S, Steger J, Hagauer J, Denner A, Murguia PF, Taudes E, Zimmermann B, Reischl R, Steinmetz PRH, Technau U. Muscle cell-type diversification is driven by bHLH transcription factor expansion and extensive effector gene duplications. Nat Commun 2023; 14:1747. [PMID: 36990990 PMCID: PMC10060217 DOI: 10.1038/s41467-023-37220-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 03/07/2023] [Indexed: 03/31/2023] Open
Abstract
Animals are typically composed of hundreds of different cell types, yet mechanisms underlying the emergence of new cell types remain unclear. Here we address the origin and diversification of muscle cells in the non-bilaterian, diploblastic sea anemone Nematostella vectensis. We discern two fast and two slow-contracting muscle cell populations, which differ by extensive sets of paralogous structural protein genes. We find that the regulatory gene set of the slow cnidarian muscles is remarkably similar to the bilaterian cardiac muscle, while the two fast muscles differ substantially from each other in terms of transcription factor profiles, though driving the same set of structural protein genes and having similar physiological characteristics. We show that anthozoan-specific paralogs of Paraxis/Twist/Hand-related bHLH transcription factors are involved in the formation of fast and slow muscles. Our data suggest that the subsequent recruitment of an entire effector gene set from the inner cell layer into the neural ectoderm contributes to the evolution of a novel muscle cell type. Thus, we conclude that extensive transcription factor gene duplications and co-option of effector modules act as an evolutionary mechanism underlying cell type diversification during metazoan evolution.
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Affiliation(s)
- Alison G Cole
- Department of Neuroscience and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria.
- Research platform Single Cell Regulation of Stem Cells, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria.
| | - Stefan M Jahnel
- Department of Neuroscience and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
- Institute of Molecular Biotechnology, Dr.-Bohr-Gasse 3, 1030, Vienna, Austria
| | - Sabrina Kaul
- Department of Neuroscience and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Julia Steger
- Department of Neuroscience and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Julia Hagauer
- Department of Neuroscience and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Andreas Denner
- Department of Neuroscience and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Patricio Ferrer Murguia
- Department of Neuroscience and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Elisabeth Taudes
- Department of Neuroscience and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Bob Zimmermann
- Department of Neuroscience and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Robert Reischl
- Department of Neuroscience and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
| | - Patrick R H Steinmetz
- Department of Neuroscience and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria
- Michael Sars Centre, University of Bergen, Thormøhlensgate 55, 5008, Bergen, Norway
| | - Ulrich Technau
- Department of Neuroscience and Developmental Biology, Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria.
- Research platform Single Cell Regulation of Stem Cells, University of Vienna, Djerassiplatz 1, 1030, Vienna, Austria.
- Max Perutz labs, University of Vienna, Dr.-Bohr-Gasse 9, 1030, Vienna, Austria.
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Gene Structure, Expression and Function Analysis of MEF2 in the Pacific White Shrimp Litopenaeus vannamei. Int J Mol Sci 2023; 24:ijms24065832. [PMID: 36982906 PMCID: PMC10051702 DOI: 10.3390/ijms24065832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/08/2023] [Accepted: 03/15/2023] [Indexed: 03/22/2023] Open
Abstract
The Pacific white shrimp Litopenaeus vannamei is the most economically important crustacean in the world. The growth and development of shrimp muscle has always been the focus of attention. Myocyte Enhancer Factor 2 (MEF2), a member of MADS transcription factor, has an essential influence on various growth and development programs, including myogenesis. In this study, based on the genome and transcriptome data of L. vannamei, the gene structure and expression profiles of MEF2 were characterized. We found that the LvMEF2 was widely expressed in various tissues, mainly in the Oka organ, brain, intestine, heart, and muscle. Moreover, LvMEF2 has a large number of splice variants, and the main forms are the mutually exclusive exon and alternative 5′ splice site. The expression profiles of the LvMEF2 splice variants varied under different conditions. Interestingly, some splice variants have tissue or developmental expression specificity. After RNA interference into LvMEF2, the increment in the body length and weight decreased significantly and even caused death, suggesting that LvMEF2 can affect the growth and survival of L. vannamei. Transcriptome analysis showed that after LvMEF2 was knocked down, the protein synthesis and immune-related pathways were affected, and the associated muscle protein synthesis decreased, indicating that LvMEF2 affected muscle formation and the immune system. The results provide an important basis for future studies of the MEF2 gene and the mechanism of muscle growth and development in shrimp.
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Schwaiger M, Andrikou C, Dnyansagar R, Murguia PF, Paganos P, Voronov D, Zimmermann B, Lebedeva T, Schmidt HA, Genikhovich G, Benvenuto G, Arnone MI, Technau U. An ancestral Wnt-Brachyury feedback loop in axial patterning and recruitment of mesoderm-determining target genes. Nat Ecol Evol 2022; 6:1921-1939. [PMID: 36396969 DOI: 10.1038/s41559-022-01905-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/12/2022] [Indexed: 11/18/2022]
Abstract
Transcription factors are crucial drivers of cellular differentiation during animal development and often share ancient evolutionary origins. The T-box transcription factor Brachyury plays a pivotal role as an early mesoderm determinant and neural repressor in vertebrates; yet, the ancestral function and key evolutionary transitions of the role of this transcription factor remain obscure. Here, we present a genome-wide target-gene screen using chromatin immunoprecipitation sequencing in the sea anemone Nematostella vectensis, an early branching non-bilaterian, and the sea urchin Strongylocentrotus purpuratus, a representative of the sister lineage of chordates. Our analysis reveals an ancestral gene regulatory feedback loop connecting Brachyury, FoxA and canonical Wnt signalling involved in axial patterning that predates the cnidarian-bilaterian split about 700 million years ago. Surprisingly, we also found that part of the gene regulatory network controlling the fate of neuromesodermal progenitors in vertebrates was already present in the common ancestor of cnidarians and bilaterians. However, while several endodermal and neuronal Brachyury target genes are ancestrally shared, hardly any of the key mesodermal downstream targets in vertebrates are found in the sea anemone or the sea urchin. Our study suggests that a limited number of target genes involved in mesoderm formation were newly acquired in the vertebrate lineage, leading to a dramatic shift in the function of this ancestral developmental regulator.
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Affiliation(s)
- Michaela Schwaiger
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences,University of Vienna, Vienna, Austria
- Friedrich Miescher Institute for Biomedical Research, Swiss Institute of Bioinformatics, Basel, Switzerland
| | - Carmen Andrikou
- Stazione Zoologica Anton Dohrn, Villa Comunale, Naples, Italy
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Rohit Dnyansagar
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences,University of Vienna, Vienna, Austria
| | - Patricio Ferrer Murguia
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences,University of Vienna, Vienna, Austria
| | | | - Danila Voronov
- Stazione Zoologica Anton Dohrn, Villa Comunale, Naples, Italy
| | - Bob Zimmermann
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences,University of Vienna, Vienna, Austria
| | - Tatiana Lebedeva
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences,University of Vienna, Vienna, Austria
| | - Heiko A Schmidt
- Center for Integrative Bioinformatics Vienna, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Grigory Genikhovich
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences,University of Vienna, Vienna, Austria
| | | | | | - Ulrich Technau
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences,University of Vienna, Vienna, Austria.
- Max Perutz Labs, University of Vienna, Vienna, Austria.
- Research Platform 'Single Cell Regulation of Stem Cells', University of Vienna, Vienna, Austria.
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Insights into how development and life-history dynamics shape the evolution of venom. EvoDevo 2021; 12:1. [PMID: 33413660 PMCID: PMC7791878 DOI: 10.1186/s13227-020-00171-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 12/22/2020] [Indexed: 02/07/2023] Open
Abstract
Venomous animals are a striking example of the convergent evolution of a complex trait. These animals have independently evolved an apparatus that synthesizes, stores, and secretes a mixture of toxic compounds to the target animal through the infliction of a wound. Among these distantly related animals, some can modulate and compartmentalize functionally distinct venoms related to predation and defense. A process to separate distinct venoms can occur within and across complex life cycles as well as more streamlined ontogenies, depending on their life-history requirements. Moreover, the morphological and cellular complexity of the venom apparatus likely facilitates the functional diversity of venom deployed within a given life stage. Intersexual variation of venoms has also evolved further contributing to the massive diversity of toxic compounds characterized in these animals. These changes in the biochemical phenotype of venom can directly affect the fitness of these animals, having important implications in their diet, behavior, and mating biology. In this review, we explore the current literature that is unraveling the temporal dynamics of the venom system that are required by these animals to meet their ecological functions. These recent findings have important consequences in understanding the evolution and development of a convergent complex trait and its organismal and ecological implications.
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Zullo L, Bozzo M, Daya A, Di Clemente A, Mancini FP, Megighian A, Nesher N, Röttinger E, Shomrat T, Tiozzo S, Zullo A, Candiani S. The Diversity of Muscles and Their Regenerative Potential across Animals. Cells 2020; 9:cells9091925. [PMID: 32825163 PMCID: PMC7563492 DOI: 10.3390/cells9091925] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 02/06/2023] Open
Abstract
Cells with contractile functions are present in almost all metazoans, and so are the related processes of muscle homeostasis and regeneration. Regeneration itself is a complex process unevenly spread across metazoans that ranges from full-body regeneration to partial reconstruction of damaged organs or body tissues, including muscles. The cellular and molecular mechanisms involved in regenerative processes can be homologous, co-opted, and/or evolved independently. By comparing the mechanisms of muscle homeostasis and regeneration throughout the diversity of animal body-plans and life cycles, it is possible to identify conserved and divergent cellular and molecular mechanisms underlying muscle plasticity. In this review we aim at providing an overview of muscle regeneration studies in metazoans, highlighting the major regenerative strategies and molecular pathways involved. By gathering these findings, we wish to advocate a comparative and evolutionary approach to prompt a wider use of “non-canonical” animal models for molecular and even pharmacological studies in the field of muscle regeneration.
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Affiliation(s)
- Letizia Zullo
- Istituto Italiano di Tecnologia, Center for Micro-BioRobotics & Center for Synaptic Neuroscience and Technology (NSYN), 16132 Genova, Italy;
- IRCCS Ospedale Policlinico San Martino, 16132 Genova, Italy
- Correspondence: (L.Z.); (A.Z.)
| | - Matteo Bozzo
- Laboratory of Developmental Neurobiology, Department of Earth, Environment and Life Sciences, University of Genova, Viale Benedetto XV 5, 16132 Genova, Italy; (M.B.); (S.C.)
| | - Alon Daya
- Faculty of Marine Sciences, Ruppin Academic Center, Michmoret 40297, Israel; (A.D.); (N.N.); (T.S.)
| | - Alessio Di Clemente
- Istituto Italiano di Tecnologia, Center for Micro-BioRobotics & Center for Synaptic Neuroscience and Technology (NSYN), 16132 Genova, Italy;
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy
| | | | - Aram Megighian
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy;
- Padova Neuroscience Center, University of Padova, 35131 Padova, Italy
| | - Nir Nesher
- Faculty of Marine Sciences, Ruppin Academic Center, Michmoret 40297, Israel; (A.D.); (N.N.); (T.S.)
| | - Eric Röttinger
- Institute for Research on Cancer and Aging (IRCAN), Université Côte d’Azur, CNRS, INSERM, 06107 Nice, France;
| | - Tal Shomrat
- Faculty of Marine Sciences, Ruppin Academic Center, Michmoret 40297, Israel; (A.D.); (N.N.); (T.S.)
| | - Stefano Tiozzo
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Sorbonne Université, CNRS, 06230 Paris, France;
| | - Alberto Zullo
- Department of Science and Technology, University of Sannio, 82100 Benevento, Italy;
- Correspondence: (L.Z.); (A.Z.)
| | - Simona Candiani
- Laboratory of Developmental Neurobiology, Department of Earth, Environment and Life Sciences, University of Genova, Viale Benedetto XV 5, 16132 Genova, Italy; (M.B.); (S.C.)
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Technau U. Gastrulation and germ layer formation in the sea anemone Nematostella vectensis and other cnidarians. Mech Dev 2020; 163:103628. [PMID: 32603823 DOI: 10.1016/j.mod.2020.103628] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 05/23/2020] [Accepted: 06/19/2020] [Indexed: 01/03/2023]
Abstract
Among the basally branching metazoans, cnidarians display well-defined gastrulation processes leading to a diploblastic body plan, consisting of an endodermal and an ectodermal cell layer. As the outgroup to all Bilateria, cnidarians are an interesting group to investigate ancestral developmental mechanisms. Interestingly, all known gastrulation mechanisms known in Bilateria are already found in different species of Cnidaria. Here I review the morphogenetic processes found in different Cnidaria and focus on the investigation of the cellular and molecular mechanisms in the sea anemone Nematostella vectensis, which has been a major model organism among cnidarians for evolutionary developmental biology. Many of the genes involved in germ layer specification and morphogenetic processes in Bilateria are also found active during gastrulation of Nematostella and other cnidarians, suggesting an ancestral role of this process. The molecular analyses indicate a tight link between gastrulation and axis patterning processes by Wnt and FGF signaling. Interestingly, the endodermal layer displays many features of the mesodermal layer in Bilateria, while the pharyngeal ectoderm has an endodermal expression profile. Comparative analyses as well as experimental studies using embryonic aggregates suggest that minor differences in the gene regulatory networks allow the embryo to transition relatively easily from one mode of gastrulation to another.
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Affiliation(s)
- Ulrich Technau
- University of Vienna, Dept. of Neurosciences and Developmental Biology, Althanstrasse 14, 1090 Wien, Austria.
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Zancolli G, Casewell NR. Venom Systems as Models for Studying the Origin and Regulation of Evolutionary Novelties. Mol Biol Evol 2020; 37:2777-2790. [DOI: 10.1093/molbev/msaa133] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Abstract
A central goal in biology is to determine the ways in which evolution repeats itself. One of the most remarkable examples in nature of convergent evolutionary novelty is animal venom. Across diverse animal phyla, various specialized organs and anatomical structures have evolved from disparate developmental tissues to perform the same function, that is, produce and deliver a cocktail of potent molecules to subdue prey or predators. Venomous organisms therefore offer unique opportunities to investigate the evolutionary processes of convergence of key adaptive traits, and the molecular mechanisms underlying the emergence of novel genes, cells, and tissues. Indeed, some venomous species have already proven to be highly amenable as models for developmental studies, and recent work with venom gland organoids provides manipulatable systems for directly testing important evolutionary questions. Here, we provide a synthesis of the current knowledge that could serve as a starting point for the establishment of venom systems as new models for evolutionary and molecular biology. In particular, we highlight the potential of various venomous species for the study of cell differentiation and cell identity, and the regulatory dynamics of rapidly evolving, highly expressed, tissue-specific, gene paralogs. We hope that this review will encourage researchers to look beyond traditional study organisms and consider venom systems as useful tools to explore evolutionary novelties.
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Affiliation(s)
- Giulia Zancolli
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Nicholas R Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Colgren J, Nichols SA. The significance of sponges for comparative studies of developmental evolution. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2019; 9:e359. [PMID: 31352684 DOI: 10.1002/wdev.359] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/27/2019] [Accepted: 06/27/2019] [Indexed: 12/31/2022]
Abstract
Sponges, ctenophores, placozoans, and cnidarians have key evolutionary significance in that they bracket the time interval during which organized animal tissues were first assembled, fundamental cell types originated (e.g., neurons and myocytes), and developmental patterning mechanisms evolved. Sponges in particular have often been viewed as living surrogates for early animal ancestors, largely due to similarities between their feeding cells (choanocytes) with choanoflagellates, the unicellular/colony-forming sister group to animals. Here, we evaluate these claims and highlight aspects of sponge biology with comparative value for understanding developmental evolution, irrespective of the purported antiquity of their body plan. Specifically, we argue that sponges strike a different balance between patterning and plasticity than other animals, and that environmental inputs may have prominence over genetically regulated developmental mechanisms. We then present a case study to illustrate how contractile epithelia in sponges can help unravel the complex ancestry of an ancient animal cell type, myocytes, which sponges lack. Sponges represent hundreds of millions of years of largely unexamined evolutionary experimentation within animals. Their phylogenetic placement lends them key significance for learning about the past, and their divergent biology challenges current views about the scope of animal cell and developmental biology. This article is characterized under: Comparative Development and Evolution > Evolutionary Novelties Comparative Development and Evolution > Body Plan Evolution.
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Affiliation(s)
- Jeffrey Colgren
- Department of Biological Sciences, University of Denver, Denver, Colorado
| | - Scott A Nichols
- Department of Biological Sciences, University of Denver, Denver, Colorado
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Rentzsch F, Juliano C, Galliot B. Modern genomic tools reveal the structural and cellular diversity of cnidarian nervous systems. Curr Opin Neurobiol 2019; 56:87-96. [PMID: 30654234 DOI: 10.1016/j.conb.2018.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/10/2018] [Accepted: 12/11/2018] [Indexed: 12/11/2022]
Abstract
Cnidarians shared a common ancestor with bilaterians more than 600 million years ago. This sister group relationship gives them an informative phylogenetic position for understanding the fascinating morphological and molecular cell type diversity of bilaterian nervous systems. Moreover, cnidarians display novel features such as endodermal neurogenesis and independently evolved centralizations, which provide a platform for understanding the evolution of nervous system innovations. In recent years, the application of modern genomic tools has significantly advanced our understanding of cnidarian nervous system structure and function. For example, transgenic reporter lines and gene knockdown experiments in several cnidarian species reveal a significant degree of conservation in the neurogenesis gene regulatory program, while single cell RNA sequencing projects are providing a much deeper understanding of cnidarian neural cell type diversity. At the level of neural function, the physiological properties of ion channels have been described and calcium imaging of the nervous system in whole animals has allowed for the identification of neural circuits underlying specific behaviours. Cnidarians have arrived in the modern era of molecular neurobiology and are primed to provide exciting new insights into the early evolution of nervous systems.
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Affiliation(s)
- Fabian Rentzsch
- Sars Centre for Marine Molecular Biology, Norway; Department for Biological Sciences, University of Bergen, Norway.
| | - Celina Juliano
- Department of Molecular and Cellular Biology, University of California Davis, CA 95616, United States.
| | - Brigitte Galliot
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Switzerland.
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11
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Sunagar K, Columbus-Shenkar YY, Fridrich A, Gutkovich N, Aharoni R, Moran Y. Cell type-specific expression profiling unravels the development and evolution of stinging cells in sea anemone. BMC Biol 2018; 16:108. [PMID: 30261880 PMCID: PMC6161364 DOI: 10.1186/s12915-018-0578-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 09/18/2018] [Indexed: 12/21/2022] Open
Abstract
Background Cnidocytes are specialized cells that define the phylum Cnidaria. They possess an “explosive” organelle called cnidocyst that is important for prey capture and anti-predator defense. An extraordinary morphological and functional complexity of the cnidocysts has inspired numerous studies to investigate their structure and development. However, the transcriptomes of the cells bearing these unique organelles are yet to be characterized, impeding our understanding of the genetic basis of their biogenesis. Results In this study, we generated a nematocyte reporter transgenic line of the sea anemone Nematostella vectensis using the CRISPR/Cas9 system. By using a fluorescence-activated cell sorter (FACS), we have characterized cell type-specific transcriptomic profiles of various stages of cnidocyte maturation and showed that nematogenesis (the formation of functional cnidocysts) is underpinned by dramatic shifts in the spatiotemporal gene expression. Among the genes identified as upregulated in cnidocytes were Cnido-Jun and Cnido-Fos1—cnidarian-specific paralogs of the highly conserved c-Jun and c-Fos proteins of the stress-induced AP-1 transcriptional complex. The knockdown of the cnidocyte-specific c-Jun homolog by microinjection of morpholino antisense oligomer results in disruption of normal nematogenesis. Conclusions Here, we show that the majority of upregulated genes and enriched biochemical pathways specific to cnidocytes are uncharacterized, emphasizing the need for further functional research on nematogenesis. The recruitment of the metazoan stress-related transcription factor c-Fos/c-Jun complex into nematogenesis highlights the evolutionary ingenuity and novelty associated with the formation of these highly complex, enigmatic, and phyletically unique organelles. Thus, we provide novel insights into the biology, development, and evolution of cnidocytes. Electronic supplementary material The online version of this article (10.1186/s12915-018-0578-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kartik Sunagar
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel. .,Evolutionary Venomics Lab, Centre for Ecological Sciences, Indian Institute of Science, Bangalore, 560012, India.
| | - Yaara Y Columbus-Shenkar
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
| | - Arie Fridrich
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
| | - Nadya Gutkovich
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
| | - Reuven Aharoni
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
| | - Yehu Moran
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel.
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12
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Imbriano C, Molinari S. Alternative Splicing of Transcription Factors Genes in Muscle Physiology and Pathology. Genes (Basel) 2018; 9:genes9020107. [PMID: 29463057 PMCID: PMC5852603 DOI: 10.3390/genes9020107] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 02/10/2018] [Accepted: 02/13/2018] [Indexed: 12/13/2022] Open
Abstract
Skeletal muscle formation is a multi-step process that is governed by complex networks of transcription factors. The regulation of their functions is in turn multifaceted, including several mechanisms, among them alternative splicing (AS) plays a primary role. On the other hand, altered AS has a role in the pathogenesis of numerous muscular pathologies. Despite these premises, the causal role played by the altered splicing pattern of transcripts encoding myogenic transcription factors in neuromuscular diseases has been neglected so far. In this review, we systematically investigate what has been described about the AS patterns of transcription factors both in the physiology of the skeletal muscle formation process and in neuromuscular diseases, in the hope that this may be useful in re-evaluating the potential role of altered splicing of transcription factors in such diseases.
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Affiliation(s)
- Carol Imbriano
- University of Modena and Reggio Emilia, Department of Life Sciences, Modena, Italy.
| | - Susanna Molinari
- University of Modena and Reggio Emilia, Department of Life Sciences, Modena, Italy.
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13
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Taylor MV, Hughes SM. Mef2 and the skeletal muscle differentiation program. Semin Cell Dev Biol 2017; 72:33-44. [PMID: 29154822 DOI: 10.1016/j.semcdb.2017.11.020] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 11/11/2017] [Accepted: 11/13/2017] [Indexed: 02/06/2023]
Abstract
Mef2 is a conserved and significant transcription factor in the control of muscle gene expression. In cell culture Mef2 synergises with MyoD-family members in the activation of gene expression and in the conversion of fibroblasts into myoblasts. Amongst its in vivo roles, Mef2 is required for both Drosophila muscle development and mammalian muscle regeneration. Mef2 has functions in other cell-types too, but this review focuses on skeletal muscle and surveys key findings on Mef2 from its discovery, shortly after that of MyoD, up to the present day. In particular, in vivo functions, underpinning mechanisms and areas of uncertainty are highlighted. We describe how Mef2 sits at a nexus in the gene expression network that controls the muscle differentiation program, and how Mef2 activity must be regulated in time and space to orchestrate specific outputs within the different aspects of muscle development. A theme that emerges is that there is much to be learnt about the different Mef2 proteins (from different paralogous genes, spliced transcripts and species) and how the activity of these proteins is controlled.
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Affiliation(s)
- Michael V Taylor
- School of Biosciences, Sir Martin Evans Building, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
| | - Simon M Hughes
- Randall Division of Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London SE1 1UL UK
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14
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Babonis LS, Martindale MQ. PaxA, but not PaxC, is required for cnidocyte development in the sea anemone Nematostella vectensis. EvoDevo 2017; 8:14. [PMID: 28878874 PMCID: PMC5584322 DOI: 10.1186/s13227-017-0077-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 08/16/2017] [Indexed: 12/25/2022] Open
Abstract
Background Pax genes are a family of conserved transcription factors that regulate many aspects of developmental morphogenesis, notably the development of ectodermal sensory structures including eyes. Nematostella vectensis, the starlet sea anemone, has numerous Pax orthologs, many of which are expressed early during embryogenesis. The function of Pax genes in this eyeless cnidarian is unknown. Results Here, we show that PaxA, but not PaxC, plays a critical role in the development of cnidocytes in N. vectensis. Knockdown of PaxA results in a loss of developing cnidocytes and downregulation of numerous cnidocyte-specific genes, including a variant of the transcription factor Mef2. We also demonstrate that the co-expression of Mef2 in a subset of the PaxA-expressing cells is associated with the development with a second lineage of cnidocytes and show that knockdown of the neural progenitor gene SoxB2 results in downregulation of expression of PaxA, Mef2, and several cnidocyte-specific genes. Because PaxA is not co-expressed with SoxB2 at any time during cnidocyte development, we propose a simple model for cnidogenesis whereby a SoxB2-expressing progenitor cell population undergoes division to give rise to PaxA-expressing cnidocytes, some of which also express Mef2. Discussion The role of PaxA in cnidocyte development among hydrozoans has not been studied, but the conserved role of SoxB2 in regulating the fate of a progenitor cell that gives rise to neurons and cnidocytes in Nematostella and Hydractinia echinata suggests that this SoxB2/PaxA pathway may well be conserved across cnidarians.
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Affiliation(s)
- Leslie S Babonis
- Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Blvd, St. Augustine, FL 32080 USA
| | - Mark Q Martindale
- Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Blvd, St. Augustine, FL 32080 USA.,Department of Biology, University of Florida, Gainesville, FL 32611 USA
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15
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Antagonistic BMP-cWNT signaling in the cnidarian Nematostella vectensis reveals insight into the evolution of mesoderm. Proc Natl Acad Sci U S A 2017; 114:E5608-E5615. [PMID: 28652368 DOI: 10.1073/pnas.1701607114] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Gastrulation was arguably the key evolutionary innovation that enabled metazoan diversification, leading to the formation of distinct germ layers and specialized tissues. Differential gene expression specifying cell fate is governed by the inputs of intracellular and/or extracellular signals. Beta-catenin/Tcf and the TGF-beta bone morphogenetic protein (BMP) provide critical molecular signaling inputs during germ layer specification in bilaterian metazoans, but there has been no direct experimental evidence for a specific role for BMP signaling during endomesoderm specification in the early branching metazoan Nematostella vectensis (an anthozoan cnidarian). Using forward transcriptomics, we show that beta-catenin/Tcf signaling and BMP2/4 signaling provide differential inputs into the cnidarian endomesodermal gene regulatory network (GRN) at the onset of gastrulation (24 h postfertilization) in N. vectensis Surprisingly, beta-catenin/Tcf signaling and BMP2/4 signaling regulate a subset of common downstream target genes in the GRN in opposite ways, leading to the spatial and temporal differentiation of fields of cells in the developing embryo. Thus, we show that regulatory interactions between beta-catenin/Tcf signaling and BMP2/4 signaling are required for the specification and determination of different embryonic regions and the patterning of the oral-aboral axis in Nematostella We also show functionally that the conserved "kernel" of the bilaterian heart mesoderm GRN is operational in N. vectensis, which reinforces the hypothesis that the endoderm and mesoderm in triploblastic bilaterians evolved from the bifunctional endomesoderm (gastrodermis) of a diploblastic ancestor, and that slow rhythmic contractions might have been one of the earliest functions of mesodermal tissue.
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Leclère L, Röttinger E. Diversity of Cnidarian Muscles: Function, Anatomy, Development and Regeneration. Front Cell Dev Biol 2017; 4:157. [PMID: 28168188 PMCID: PMC5253434 DOI: 10.3389/fcell.2016.00157] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 12/30/2016] [Indexed: 12/12/2022] Open
Abstract
The ability to perform muscle contractions is one of the most important and distinctive features of eumetazoans. As the sister group to bilaterians, cnidarians (sea anemones, corals, jellyfish, and hydroids) hold an informative phylogenetic position for understanding muscle evolution. Here, we review current knowledge on muscle function, diversity, development, regeneration and evolution in cnidarians. Cnidarian muscles are involved in various activities, such as feeding, escape, locomotion and defense, in close association with the nervous system. This variety is reflected in the large diversity of muscle organizations found in Cnidaria. Smooth epithelial muscle is thought to be the most common type, and is inferred to be the ancestral muscle type for Cnidaria, while striated muscle fibers and non-epithelial myocytes would have been convergently acquired within Cnidaria. Current knowledge of cnidarian muscle development and its regeneration is limited. While orthologs of myogenic regulatory factors such as MyoD have yet to be found in cnidarian genomes, striated muscle formation potentially involves well-conserved myogenic genes, such as twist and mef2. Although satellite cells have yet to be identified in cnidarians, muscle plasticity (e.g., de- and re-differentiation, fiber repolarization) in a regenerative context and its potential role during regeneration has started to be addressed in a few cnidarian systems. The development of novel tools to study those organisms has created new opportunities to investigate in depth the development and regeneration of cnidarian muscle cells and how they contribute to the regenerative process.
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Affiliation(s)
- Lucas Leclère
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) Villefranche-sur-mer, France
| | - Eric Röttinger
- Université Côte d'Azur, CNRS, INSERM, Institute for Research on Cancer and Aging (IRCAN) Nice, France
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17
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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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18
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Yasuoka Y, Shinzato C, Satoh N. The Mesoderm-Forming Gene brachyury Regulates Ectoderm-Endoderm Demarcation in the Coral Acropora digitifera. Curr Biol 2016; 26:2885-2892. [PMID: 27693135 DOI: 10.1016/j.cub.2016.08.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 07/25/2016] [Accepted: 08/04/2016] [Indexed: 12/27/2022]
Abstract
Blastoporal expression of the T-box transcription factor gene brachyury is conserved in most metazoans [1, 2]. Its role in mesoderm formation has been intensively studied in vertebrates [3-6]. However, its fundamental function near the blastopore is poorly understood in other phyla. Cnidarians are basal metazoans that are important for understanding evolution of metazoan body plans [7, 8]. Because they lack mesoderm, they have been used to investigate the evolutionary origins of mesoderm [1, 9-11]. Here, we focus on corals, a primitive clade of cnidarians that diverged from sea anemones ∼500 mya [12]. We developed a microinjection method for coral eggs to examine Brachyury functions during embryogenesis of the scleractinian coral, Acropora digitifera. Because Acropora embryos undergo pharynx formation after the blastopore closes completely [13-15], they are useful to understand Brachyury functions in gastrulation movement and pharynx formation. We show that blastoporal expression of brachyury is directly activated by Wnt/β-catenin signaling in the ectoderm of coral embryos, indicating that the regulatory axis from Wnt/β-catenin signaling to brachyury is highly conserved among eumetazoans. Loss-of-function analysis demonstrated that Brachyury is required for pharynx formation but not for gastrulation movement. Genome-wide transcriptome analysis demonstrated that genes positively regulated by Brachyury are expressed in the ectoderm of Acropora gastrulae, while negatively regulated genes are in endoderm. Therefore, germ layer demarcation around the blastopore appears to be the evolutionarily conserved role of Brachyury during gastrulation. Compared with Brachyury functions in vertebrate mesoderm-ectoderm and mesoderm-endoderm demarcation [4-6], our results suggest that the vertebrate-type mesoderm may have originated from brachyury-expressing ectoderm adjacent to endoderm.
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Affiliation(s)
- Yuuri Yasuoka
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan.
| | - Chuya Shinzato
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
| | - Noriyuki Satoh
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
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19
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Kraus Y, Aman A, Technau U, Genikhovich G. Pre-bilaterian origin of the blastoporal axial organizer. Nat Commun 2016; 7:11694. [PMID: 27229764 PMCID: PMC4895019 DOI: 10.1038/ncomms11694] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 04/12/2016] [Indexed: 01/07/2023] Open
Abstract
The startling capacity of the amphibian Spemann organizer to induce naïve cells to form a Siamese twin embryo with a second set of body axes is one of the hallmarks of developmental biology. However, the axis-inducing potential of the blastopore-associated tissue is commonly regarded as a chordate feature. Here we show that the blastopore lip of a non-bilaterian metazoan, the anthozoan cnidarian Nematostella vectensis, possesses the same capacity and uses the same molecular mechanism for inducing extra axes as chordates: Wnt/β-catenin signaling. We also demonstrate that the establishment of the secondary, directive axis in Nematostella by BMP signaling is sensitive to an initial Wnt signal, but once established the directive axis becomes Wnt-independent. By combining molecular analysis with experimental embryology, we provide evidence that the emergence of the Wnt/β-catenin driven blastopore-associated axial organizer predated the cnidarian-bilaterian split over 600 million years ago.
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Affiliation(s)
- Yulia Kraus
- Department for Molecular Evolution and Development, Centre of Organismal Systems Biology, University of Vienna, Althanstraße 14, Vienna A-1090, Austria
- Department of Evolutionary Biology, Biological Faculty, Moscow State University, Leninskiye gory 1/12, Moscow 119234, Russia
| | - Andy Aman
- Department for Molecular Evolution and Development, Centre of Organismal Systems Biology, University of Vienna, Althanstraße 14, Vienna A-1090, Austria
| | - Ulrich Technau
- Department for Molecular Evolution and Development, Centre of Organismal Systems Biology, University of Vienna, Althanstraße 14, Vienna A-1090, Austria
| | - Grigory Genikhovich
- Department for Molecular Evolution and Development, Centre of Organismal Systems Biology, University of Vienna, Althanstraße 14, Vienna A-1090, Austria
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20
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Layden MJ, Rentzsch F, Röttinger E. The rise of the starlet sea anemone Nematostella vectensis as a model system to investigate development and regeneration. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2016; 5:408-28. [PMID: 26894563 PMCID: PMC5067631 DOI: 10.1002/wdev.222] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 11/20/2015] [Accepted: 11/28/2015] [Indexed: 02/01/2023]
Abstract
Reverse genetics and next‐generation sequencing unlocked a new era in biology. It is now possible to identify an animal(s) with the unique biology most relevant to a particular question and rapidly generate tools to functionally dissect that biology. This review highlights the rise of one such novel model system, the starlet sea anemone Nematostella vectensis. Nematostella is a cnidarian (corals, jellyfish, hydras, sea anemones, etc.) animal that was originally targeted by EvoDevo researchers looking to identify a cnidarian animal to which the development of bilaterians (insects, worms, echinoderms, vertebrates, mollusks, etc.) could be compared. Studies in Nematostella have accomplished this goal and informed our understanding of the evolution of key bilaterian features. However, Nematostella is now going beyond its intended utility with potential as a model to better understand other areas such as regenerative biology, EcoDevo, or stress response. This review intends to highlight key EvoDevo insights from Nematostella that guide our understanding about the evolution of axial patterning mechanisms, mesoderm, and nervous systems in bilaterians, as well as to discuss briefly the potential of Nematostella as a model to better understand the relationship between development and regeneration. Lastly, the sum of research to date in Nematostella has generated a variety of tools that aided the rise of Nematostella to a viable model system. We provide a catalogue of current resources and techniques available to facilitate investigators interested in incorporating Nematostella into their research. WIREs Dev Biol 2016, 5:408–428. doi: 10.1002/wdev.222 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Michael J Layden
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA
| | - Fabian Rentzsch
- Sars Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Eric Röttinger
- Institute for Research on Cancer and Aging (IRCAN), CNRS UMR 7284, INSERM U1081, Université de Nice-Sophia-Antipolis, Nice, France
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21
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Technau U, Schwaiger M. Recent advances in genomics and transcriptomics of cnidarians. Mar Genomics 2015; 24 Pt 2:131-8. [PMID: 26421490 DOI: 10.1016/j.margen.2015.09.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 09/20/2015] [Accepted: 09/21/2015] [Indexed: 01/05/2023]
Abstract
The advent of the genomic era has provided important and surprising insights into the deducted genetic composition of the common ancestor of cnidarians and bilaterians. This has changed our view of how genomes of metazoans evolve and when crucial gene families arose and diverged in animal evolution. Sequencing of several cnidarian genomes showed that cnidarians share a great part of their gene repertoire as well as genome synteny with vertebrates, with less gene losses in the anthozoan cnidarian lineage than for example in ecdysozoans like Drosophila melanogaster or Caenorhabditis elegans. The Hydra genome on the other hand has evolved more rapidly indicated by more divergent sequences, more cases of gene losses and many taxonomically restricted genes. Cnidarian genomes also contain a rich repertoire of transcription factors, including those that in bilaterian model organisms regulate the development of key bilaterian traits such as mesoderm, nervous system development and bilaterality. The sea anemone Nematostella vectensis, and possibly cnidarians in general, does not only share its complex gene repertoire with bilaterians, but also the regulation of crucial developmental regulatory genes via distal enhancer elements. In addition, epigenetic modifications on DNA and chromatin are shared among eumetazoans. This suggests that most conserved genes present in our genomes today, as well as the mechanisms guiding their expression, evolved before the divergence of cnidarians and bilaterians about 600 Myr ago.
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Affiliation(s)
- Ulrich Technau
- Department of Molecular Evolution and Development, Centre of Organismal Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
| | - Michaela Schwaiger
- Department of Molecular Evolution and Development, Centre of Organismal Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
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22
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23
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Layden MJ, Martindale MQ. Non-canonical Notch signaling represents an ancestral mechanism to regulate neural differentiation. EvoDevo 2014; 5:30. [PMID: 25705370 PMCID: PMC4335385 DOI: 10.1186/2041-9139-5-30] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 08/12/2014] [Indexed: 01/22/2023] Open
Abstract
Background Cellular differentiation is a critical process during development of multicellular animals that must be tightly controlled in order to avoid precocious differentiation or failed generation of differentiated cell types. Research in flies, vertebrates, and nematodes has led to the identification of a conserved role for Notch signaling as a mechanism to regulate cellular differentiation regardless of tissue/cell type. Notch signaling can occur through a canonical pathway that results in the activation of hes gene expression by a complex consisting of the Notch intracellular domain, SuH, and the Mastermind co-activator. Alternatively, Notch signaling can occur via a non-canonical mechanism that does not require SuH or activation of hes gene expression. Regardless of which mechanism is being used, high Notch activity generally inhibits further differentiation, while low Notch activity promotes differentiation. Flies, vertebrates, and nematodes are all bilaterians, and it is therefore unclear if Notch regulation of differentiation is a bilaterian innovation, or if it represents a more ancient mechanism in animals. Results To reconstruct the ancestral function of Notch signaling we investigate Notch function in a non-bilaterian animal, the sea anemone Nematostella vectensis (Cnidaria). Morpholino or pharmacological knockdown of Nvnotch causes increased expression of the neural differentiation gene NvashA. Conversely, overactivation of Notch activity resulting from overexpression of the Nvnotch intracellular domain or by overexpression of the Notch ligand Nvdelta suppresses NvashA. We also knocked down or overactivated components of the canonical Notch signaling pathway. We disrupted NvsuH with morpholino or by overexpressing a dominant negative NvsuH construct. We saw no change in expression levels for Nvhes genes or NvashA. Overexpression of Nvhes genes did not alter NvashA expression levels. Lastly, we tested additional markers associated with neuronal differentiation and observed that non-canonical Notch signaling broadly suppresses neural differentiation in Nematostella. Conclusions We conclude that one ancestral role for Notch in metazoans was to regulate neural differentiation. Remarkably, we found no evidence for a functional canonical Notch pathway during Nematostella embryogenesis, suggesting that the non-canonical hes-independent Notch signaling mechanism may represent an ancestral Notch signaling pathway.
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Affiliation(s)
- Michael J Layden
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015, USA
| | - Mark Q Martindale
- Whitney Laboratory for Marine Bioscience, University of Florida, St Augustine, FL 32080, USA
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Ganassi M, Badodi S, Polacchini A, Baruffaldi F, Battini R, Hughes SM, Hinits Y, Molinari S. Distinct functions of alternatively spliced isoforms encoded by zebrafish mef2ca and mef2cb. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1839:559-70. [PMID: 24844180 PMCID: PMC4064114 DOI: 10.1016/j.bbagrm.2014.05.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 04/29/2014] [Accepted: 05/12/2014] [Indexed: 01/06/2023]
Abstract
In mammals, an array of MEF2C proteins is generated by alternative splicing (AS), yet specific functions have not been ascribed to each isoform. Teleost fish possess two MEF2C paralogues, mef2ca and mef2cb. In zebrafish, the Mef2cs function to promote cardiomyogenic differentiation and myofibrillogenesis in nascent skeletal myofibers. We found that zebrafish mef2ca and mef2cb are alternatively spliced in the coding exons 4–6 region and these splice variants differ in their biological activity. Of the two, mef2ca is more abundantly expressed in developing skeletal muscle, its activity is tuned through zebrafish development by AS. By 24 hpf, we found the prevalent expression of the highly active full length protein in differentiated muscle in the somites. The splicing isoform of mef2ca that lacks exon 5 (mef2ca 4–6), encodes a protein that has 50% lower transcriptional activity, and is found mainly earlier in development, before muscle differentiation. mef2ca transcripts including exon 5 (mef2ca 4–5–6) are present early in the embryo. Over-expression of this isoform alters the expression of genes involved in early dorso-ventral patterning of the embryo such as chordin, nodal related 1 and goosecoid, and induces severe developmental defects. AS of mef2cb generates a long splicing isoform in the exon 5 region (Mef2cbL) that predominates during somitogenesis. Mef2cbL contains an evolutionarily conserved domain derived from exonization of a fragment of intron 5, which confers the ability to induce ectopic muscle in mesoderm upon over-expression of the protein. Taken together, the data show that AS is a significant regulator of Mef2c activity. mef2ca and mef2cb gene products are alternatively spliced in zebrafish. Inclusion of exon 5 in mef2ca transcripts is regulated during zebrafish development. Exon 5 confers on Mef2ca the ability to activate early patterning genes. Mef2cb includes an extra octapeptide encoded by a region of intron 5. Inclusion of the extra-octapeptide confers on Mef2cb pro-myogenic activity.
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Affiliation(s)
- M Ganassi
- University of Modena and Reggio Emilia, Department of Life Sciences, Italy; Randall Division of Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, SE1 1UL, UK
| | - S Badodi
- University of Modena and Reggio Emilia, Department of Life Sciences, Italy
| | - A Polacchini
- University of Modena and Reggio Emilia, Department of Life Sciences, Italy
| | - F Baruffaldi
- University of Modena and Reggio Emilia, Department of Life Sciences, Italy
| | - R Battini
- University of Modena and Reggio Emilia, Department of Life Sciences, Italy
| | - S M Hughes
- Randall Division of Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, SE1 1UL, UK
| | - Y Hinits
- Randall Division of Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, SE1 1UL, UK.
| | - S Molinari
- University of Modena and Reggio Emilia, Department of Life Sciences, Italy.
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Babonis LS, Martindale MQ. Old cell, new trick? Cnidocytes as a model for the evolution of novelty. Integr Comp Biol 2014; 54:714-22. [PMID: 24771087 DOI: 10.1093/icb/icu027] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Understanding how new cell types arise is critical for understanding the evolution of organismal complexity. Questions of this nature, however, can be difficult to answer due to the challenge associated with defining the identity of a truly novel cell. Cnidarians (anemones, jellies, and their allies) provide a unique opportunity to investigate the molecular regulation and development of cell-novelty because they possess a cell that is unique to the cnidarian lineage and that also has a very well-characterized phenotype: the cnidocyte (stinging cell). Because cnidocytes are thought to differentiate from the cell lineage that also gives rise to neurons, cnidocytes can be expected to express many of the same genes expressed in their neural "sister" cells. Conversely, only cnidocytes posses a cnidocyst (the explosive organelle that gives cnidocytes their sting); therefore, those genes or gene-regulatory relationships required for the development of the cnidocyst can be expected to be expressed uniquely (or in unique combination) in cnidocytes. This system provides an important opportunity to: (1) construct the gene-regulatory network (GRN) underlying the differentiation of cnidocytes, (2) assess the relative contributions of both conserved and derived genes in the cnidocyte GRN, and (3) test hypotheses about the role of novel regulatory relationships in the generation of novel cell types. In this review, we summarize common challenges to studying the evolution of novelty, introduce the utility of cnidocyte differentiation in the model cnidarian, Nematostella vectensis, as a means of overcoming these challenges, and describe an experimental approach that leverages comparative tissue-specific transcriptomics to generate hypotheses about the GRNs underlying the acquisition of the cnidocyte identity.
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Affiliation(s)
- Leslie S Babonis
- Whitney Laboratory for Marine Bioscience, University of Florida, 9505 N Oceanshore Blvd, St. Augustine, FL 32080, USA
| | - Mark Q Martindale
- Whitney Laboratory for Marine Bioscience, University of Florida, 9505 N Oceanshore Blvd, St. Augustine, FL 32080, USA
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Layden MJ, Röttinger E, Wolenski FS, Gilmore TD, Martindale MQ. Microinjection of mRNA or morpholinos for reverse genetic analysis in the starlet sea anemone, Nematostella vectensis. Nat Protoc 2013; 8:924-34. [PMID: 23579781 DOI: 10.1038/nprot.2013.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We describe a protocol for microinjection of embryos for an emerging model system, the cnidarian sea anemone, Nematostella vectensis. In addition, we provide protocols for carrying out overexpression and knockdown of gene function through microinjection of in vitro-translated mRNAs or gene-specific oligonucleotide morpholinos (MOs), respectively. Our approach is simple, and it takes advantage of the natural adherence properties of the early embryo to position them in a single layer on a polystyrene dish. Embryos are visualized on a dissecting microscope equipped with epifluorescence and injected with microinjection needles using a picospritzer forced-air injection system. A micromanipulator is used to guide the needle to impale individual embryos. Injection takes ∼1.5 h, and an experienced researcher can inject ∼2,000 embryos in a single session. With the availability of the published Nematostella genome, the entire protocol, including cloning and transcription of mRNAs, can be carried out in ∼1 week.
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Affiliation(s)
- Michael J Layden
- The Whitney Marine Laboratory for Marine Science, University of Florida, St. Augustine, Florida, USA
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Chiodin M, Børve A, Berezikov E, Ladurner P, Martinez P, Hejnol A. Mesodermal gene expression in the acoel Isodiametra pulchra indicates a low number of mesodermal cell types and the endomesodermal origin of the gonads. PLoS One 2013; 8:e55499. [PMID: 23405161 PMCID: PMC3566195 DOI: 10.1371/journal.pone.0055499] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2012] [Accepted: 12/23/2012] [Indexed: 01/23/2023] Open
Abstract
Acoelomorphs are bilaterally symmetric small marine worms that lack a coelom and possess a digestive system with a single opening. Two alternative phylogenetic positions of this group within the animal tree are currently debated. In one view, Acoelomorpha is the sister group to all remaining Bilateria and as such, is a morphologically simple stepping stone in bilaterian evolution. In the other, the group is a lineage within the Deuterostomia, and therefore, has derived a simple morphology from a more complex ancestor. Acoels and the closely related Nemertodermatida and Xenoturbellida, which together form the Acoelomorpha, possess a very limited number of cell types. To further investigate the diversity and origin of mesodermal cell types we describe the expression pattern of 12 orthologs of bilaterian mesodermal markers including Six1/2, Twist, FoxC, GATA4/5/6, in the acoel Isodiametra pulchra. All the genes are expressed in stem cells (neoblasts), gonads, and at least subsets of the acoel musculature. Most are expressed in endomesodermal compartments of I. pulchra developing embryos similar to what has been described in cnidarians. Our molecular evidence indicates a very limited number of mesodermal cell types and suggests an endomesodermal origin of the gonads and the stem cell system. We discuss our results in light of the two prevailing phylogenetic positions of Acoelomorpha.
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Affiliation(s)
- Marta Chiodin
- Departament de Genètica, Universitat de Barcelona, Barcelona, Spain
| | - Aina Børve
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | | | - Peter Ladurner
- Institute of Zoology and Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Pedro Martinez
- Departament de Genètica, Universitat de Barcelona, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Andreas Hejnol
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
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Röttinger E, Dahlin P, Martindale MQ. A framework for the establishment of a cnidarian gene regulatory network for "endomesoderm" specification: the inputs of ß-catenin/TCF signaling. PLoS Genet 2012; 8:e1003164. [PMID: 23300467 PMCID: PMC3531958 DOI: 10.1371/journal.pgen.1003164] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 10/27/2012] [Indexed: 12/03/2022] Open
Abstract
Understanding the functional relationship between intracellular factors and
extracellular signals is required for reconstructing gene regulatory networks
(GRN) involved in complex biological processes. One of the best-studied
bilaterian GRNs describes endomesoderm specification and predicts that both
mesoderm and endoderm arose from a common GRN early in animal evolution.
Compelling molecular, genomic, developmental, and evolutionary evidence supports
the hypothesis that the bifunctional gastrodermis of the cnidarian-bilaterian
ancestor is derived from the same evolutionary precursor of both endodermal and
mesodermal germ layers in all other triploblastic bilaterian animals. We have
begun to establish the framework of a provisional cnidarian
“endomesodermal” gene regulatory network in the sea anemone,
Nematostella vectensis, by using a genome-wide microarray
analysis on embryos in which the canonical Wnt/ß-catenin pathway was
ectopically targeted for activation by two distinct pharmaceutical agents
(lithium chloride and 1-azakenpaullone) to identify potential targets of
endomesoderm specification. We characterized 51 endomesodermally expressed
transcription factors and signaling molecule genes (including 18 newly
identified) with fine-scale temporal (qPCR) and spatial (in
situ) analysis to define distinct co-expression domains within the
animal plate of the embryo and clustered genes based on their earliest zygotic
expression. Finally, we determined the input of the canonical
Wnt/ß-catenin pathway into the cnidarian endomesodermal GRN using
morpholino and mRNA overexpression experiments to show that NvTcf/canonical Wnt
signaling is required to pattern both the future endomesodermal and ectodermal
domains prior to gastrulation, and that both BMP and FGF (but not Notch)
pathways play important roles in germ layer specification in this animal. We
show both evolutionary conserved as well as profound differences in
endomesodermal GRN structure compared to bilaterians that may provide
fundamental insight into how GRN subcircuits have been adopted, rewired, or
co-opted in various animal lineages that give rise to specialized endomesodermal
cell types. Cnidarians (anemones, corals, and “jellyfish”) are an animal group
whose adults possess derivatives of only two germ layers: ectoderm and a
bifunctional (absorptive and contractile) gastrodermal (gut) layer. Cnidarians
are the closest living relatives to bilaterally symmetrical animals that possess
all three germ layers (ecto, meso, and endoderm); and compelling molecular,
genomic, developmental, and evolutionary evidence exists to demonstrate that the
cnidarian gastrodermis is evolutionarily related to both endodermal and
mesodermal germ layers in all other triploblastic bilaterian animals. Little is
known about endomesoderm specification in cnidarians. In this study, we
constructed the framework of a cnidarian endomesodermal gene regulatory network
in the sea anemone, Nematostella vectensis, using a combination
of experimental approaches. We identified and characterized by both qPCR and
in situ hybridization 51 genes expressed in defined domains
within the presumptive endomesoderm. In addition, we functionally demonstrate
that Wnt/Tcf signaling is crucial for regionalized expression of a defined
subset of these genes prior to gut formation and endomesoderm maintenance. Our
results support the idea of an ancient gene regulatory network underlying
endomesoderm specification that involves inputs from multiple signaling pathways
(Wnt, FGF, BMP, but not Notch) early in development, that are temporarily
uncoupled in bilaterian animals.
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Affiliation(s)
- Eric Röttinger
- Kewalo Marine Laboratory, Pacific Biosciences Research Center,
University of Hawai'i, Honolulu, Hawai'i, United States of
America
| | - Paul Dahlin
- Kewalo Marine Laboratory, Pacific Biosciences Research Center,
University of Hawai'i, Honolulu, Hawai'i, United States of
America
| | - Mark Q. Martindale
- Kewalo Marine Laboratory, Pacific Biosciences Research Center,
University of Hawai'i, Honolulu, Hawai'i, United States of
America
- * E-mail:
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Short S, Kozmik Z, Holland LZ. The function and developmental expression of alternatively spliced isoforms of amphioxus and Xenopus laevis Pax2/5/8 genes: revealing divergence at the invertebrate to vertebrate transition. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2012; 318:555-71. [PMID: 22791613 DOI: 10.1002/jez.b.22460] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 05/07/2012] [Accepted: 05/28/2012] [Indexed: 01/14/2023]
Abstract
Pax genes encode highly conserved transcription factors vital for metazoan development. Pax transcripts, particularly those in Group II (Pax2/5/8), are extensively alternatively spliced. This study compares the transcriptional activation capacity and developmental stage-specific expression of major isoforms of Group II Pax proteins in amphioxus (Branchiostoma floridae) and in Xenopus laevis. The comparison reveals considerable divergence of splice forms between the lineages, with the X. laevis Group II Pax genes (Pax2, Pax5, and Pax8) possessing a greater repertoire of regulated and functionally distinct splice forms than the single amphioxus gene (Pax2/5/8). Surprisingly, some apparently conserved splice forms are expressed at quite different levels during development in the two organisms and present different capacities to activate transcription. However, despite this divergence, the combinatorial transcriptional activation capacity of the isoforms present in early X. laevis and amphioxus development are broadly similar. This suggests that the some of the conserved functional roles, implied by the expression of Group II Pax genes in homologous tissues of amphioxus and X. laevis embryos, may depend upon the combination of isoforms expressed in a particular tissue at a particular time in development. Thus, during early development, the evolutionary constraint on the net effect of several isoforms co-expressed in a given tissue may be more strict than that on specific isoforms. This flexibility may facilitate the appearance of new exons and splicing patterns in the vertebrate duplicates, leading to isoforms with subtly distinct functions critical to the subsequent development of vertebrate-specific cell types and structures.
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Affiliation(s)
- Stephen Short
- Institute of Marine Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth, Hampshire, United Kingdom
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