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Structural and Functional Characterization of the FGF Signaling Pathway in Regeneration of the Polychaete Worm Alitta virens (Annelida, Errantia). Genes (Basel) 2021; 12:genes12060788. [PMID: 34063978 PMCID: PMC8224027 DOI: 10.3390/genes12060788] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 05/13/2021] [Accepted: 05/14/2021] [Indexed: 12/16/2022] Open
Abstract
Epimorphic regeneration of lost body segments is a widespread phenomenon across annelids. However, the molecular inducers of the cell sources for this reparative morphogenesis have not been identified. In this study, we focused on the role of fibroblast growth factor (FGF) signaling in the posterior regeneration of Alitta virens. For the first time, we showed an early activation of FGF ligands and receptor expression in an annelid regenerating after amputation. The expression patterns indicate that the entire regenerative bud is competent to FGFs, whose activity precedes the initiation of cell proliferation. The critical requirement of FGF signaling, especially at early stages, is also supported by inhibitor treatments followed by proliferation assay, demonstrating that induction of blastemal cells depends on FGFs. Our results show that FGF signaling pathway is a key player in regenerative response, while the FGF-positive wound epithelium, ventral nerve cord and some mesodermal cells around the gut could be the inducing tissues. This mechanism resembles reparative regeneration of vertebrate appendages suggesting such a response to the injury may be ancestral for all bilaterians.
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Czarkwiani A, Dylus DV, Carballo L, Oliveri P. FGF signalling plays similar roles in development and regeneration of the skeleton in the brittle star Amphiura filiformis. Development 2021; 148:dev180760. [PMID: 34042967 PMCID: PMC8180256 DOI: 10.1242/dev.180760] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 04/13/2021] [Indexed: 12/16/2022]
Abstract
Regeneration as an adult developmental process is in many aspects similar to embryonic development. Although many studies point out similarities and differences, no large-scale, direct and functional comparative analyses between development and regeneration of a specific cell type or structure in one animal exist. Here, we use the brittle star Amphiura filiformis to characterise the role of the FGF signalling pathway during skeletal development in embryos and arm regeneration. In both processes, we find ligands expressed in ectodermal cells that flank underlying skeletal mesenchymal cells, which express the receptors. Perturbation of FGF signalling showed inhibited skeleton formation in both embryogenesis and regeneration, without affecting other key developmental processes. Differential transcriptome analysis finds mostly differentiation genes rather than transcription factors to be downregulated in both contexts. Moreover, comparative gene analysis allowed us to discover brittle star-specific differentiation genes. In conclusion, our results show that the FGF pathway is crucial for skeletogenesis in the brittle star, as in other deuterostomes, and provide evidence for the re-deployment of a developmental gene regulatory module during regeneration.
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Affiliation(s)
- Anna Czarkwiani
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - David V. Dylus
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
- Centre for Mathematics, Physics and Engineering in the Life Sciences and Experimental Biology, University College London, London WC1E 6BT, UK
| | - Luisana Carballo
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Paola Oliveri
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
- Centre for Life's Origin and Evolution (CLOE), University College London, London WC1E 6BT, UK
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Fan TP, Ting HC, Yu JK, Su YH. Reiterative use of FGF signaling in mesoderm development during embryogenesis and metamorphosis in the hemichordate Ptychodera flava. BMC Evol Biol 2018; 18:120. [PMID: 30075704 PMCID: PMC6091094 DOI: 10.1186/s12862-018-1235-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 07/26/2018] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Mesoderm is generally considered to be a germ layer that is unique to Bilateria, and it develops into diverse tissues, including muscle, and in the case of vertebrates, the skeleton and notochord. Studies on various deuterostome animals have demonstrated that fibroblast growth factor (FGF) signaling is required for the formation of many mesodermal structures, such as vertebrate somites, from which muscles are differentiated, and muscles in sea urchin embryos, suggesting an ancient role of FGF signaling in muscle development. However, the formation of trunk muscles in invertebrate chordates is FGF-independent, leading to ambiguity about this ancient role in deuterostomes. To further understand the role of FGF signaling during deuterostome evolution, we investigated the development of mesodermal structures during embryogenesis and metamorphosis in Ptychodera flava, an indirect-developing hemichordate that has larval morphology similar to echinoderms and adult body features that are similar to chordates. RESULTS Here we show that genes encoding FGF ligands, FGF receptors and transcription factors that are known to be involved in mesoderm formation and myogenesis are expressed dynamically during embryogenesis and metamorphosis. FGF signaling at the early gastrula stage is required for the specification of the mesodermal cell fate in P. flava. The mesoderm cells are then differentiated stepwise into the hydroporic canal, the pharyngeal muscle and the muscle string; formation of the last two muscular structures are controlled by FGF signaling. Moreover, augmentation of FGF signaling during metamorphosis accelerated the process, facilitating the transformation from cilia-driven swimming larvae into muscle-driven worm-like juveniles. CONCLUSIONS Our data show that FGF signaling is required for mesoderm induction and myogenesis in the P. flava embryo, and it is reiteratively used for the morphological transition during metamorphosis. The dependence of muscle development on FGF signaling in both planktonic larvae and sand-burrowing worms supports its ancestral role in deuterostomes.
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Affiliation(s)
- Tzu-Pei Fan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, 11529, Taiwan.,Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Rd., Sec. 2, Nankang, Taipei, 11529, Taiwan.,Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 40227, Taiwan
| | - Hsiu-Chi Ting
- Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Rd., Sec. 2, Nankang, Taipei, 11529, Taiwan
| | - Jr-Kai Yu
- Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Rd., Sec. 2, Nankang, Taipei, 11529, Taiwan
| | - Yi-Hsien Su
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, 11529, Taiwan. .,Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Rd., Sec. 2, Nankang, Taipei, 11529, Taiwan. .,Biotechnology Center, National Chung Hsing University, Taichung, 40227, Taiwan.
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Genomics going wild: Marine sampling for studies of evolution and development. Mar Genomics 2015; 24 Pt 2:119-20. [PMID: 26555400 DOI: 10.1016/j.margen.2015.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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