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Rozenblit F, Gollisch T. What the salamander eye has been telling the vision scientist's brain. Semin Cell Dev Biol 2020; 106:61-71. [PMID: 32359891 PMCID: PMC7493835 DOI: 10.1016/j.semcdb.2020.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/16/2020] [Accepted: 04/16/2020] [Indexed: 12/30/2022]
Abstract
Salamanders have been habitual residents of research laboratories for more than a century, and their history in science is tightly interwoven with vision research. Nevertheless, many vision scientists - even those working with salamanders - may be unaware of how much our knowledge about vision, and particularly the retina, has been shaped by studying salamanders. In this review, we take a tour through the salamander history in vision science, highlighting the main contributions of salamanders to our understanding of the vertebrate retina. We further point out specificities of the salamander visual system and discuss the perspectives of this animal system for future vision research.
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Affiliation(s)
- Fernando Rozenblit
- Department of Ophthalmology, University Medical Center Göttingen, 37073, Göttingen, Germany; Bernstein Center for Computational Neuroscience Göttingen, 37077, Göttingen, Germany
| | - Tim Gollisch
- Department of Ophthalmology, University Medical Center Göttingen, 37073, Göttingen, Germany; Bernstein Center for Computational Neuroscience Göttingen, 37077, Göttingen, Germany.
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Buchholz DR. Xenopus metamorphosis as a model to study thyroid hormone receptor function during vertebrate developmental transitions. Mol Cell Endocrinol 2017; 459:64-70. [PMID: 28363743 DOI: 10.1016/j.mce.2017.03.020] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 03/13/2017] [Accepted: 03/21/2017] [Indexed: 12/18/2022]
Abstract
A hormone-dependent developmental transition from aquatic to terrestrial existence occurs in all tetrapod vertebrates, such as birth, hatching, and metamorphosis. Thyroid hormones (TH) and their receptors (TRs) are key players in the tissue transformations comprising vertebrate developmental transitions. The African clawed frog, Xenopus, is a premier model for the role of TRs in developmental transitions because of the numerous and dramatic TH-dependent tissue transformations during metamorphosis and because of the endocrine, molecular, and genomic resources available. TRs are nuclear receptors that repress TH-response genes when plasma TH is minimal and that activate those same genes to induce tissue-specific gene regulation cascades when TH plasma levels increase. Tissue-specific TR expression levels help determine tissue sensitivity and responsivity to TH thereby regulating the initiation and rate of developmental change in TH-sensitive tissues which govern the tissue developmental asynchrony observed during metamorphosis. This review highlighting Xenopus presents the key experimental findings underpinning the roles TRs play in control of vertebrate developmental transitions.
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Affiliation(s)
- Daniel R Buchholz
- Department of Biological Sciences, University of Cincinnati, 312 Clifton Ct., Cincinnati, OH, 45221 USA.
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Alves RN, Gomes AS, Stueber K, Tine M, Thorne MAS, Smáradóttir H, Reinhard R, Clark MS, Rønnestad I, Power DM. The transcriptome of metamorphosing flatfish. BMC Genomics 2016; 17:413. [PMID: 27233904 PMCID: PMC4884423 DOI: 10.1186/s12864-016-2699-x] [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: 01/20/2016] [Accepted: 05/06/2016] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Flatfish metamorphosis denotes the extraordinary transformation of a symmetric pelagic larva into an asymmetric benthic juvenile. Metamorphosis in vertebrates is driven by thyroid hormones (THs), but how they orchestrate the cellular, morphological and functional modifications associated with maturation to juvenile/adult states in flatfish is an enigma. Since THs act via thyroid receptors that are ligand activated transcription factors, we hypothesized that the maturation of tissues during metamorphosis should be preceded by significant modifications in the transcriptome. Targeting the unique metamorphosis of flatfish and taking advantage of the large size of Atlantic halibut (Hippoglossus hippoglossus) larvae, we determined the molecular basis of TH action using RNA sequencing. RESULTS De novo assembly of sequences for larval head, skin and gastrointestinal tract (GI-tract) yielded 90,676, 65,530 and 38,426 contigs, respectively. More than 57 % of the assembled sequences were successfully annotated using a multi-step Blast approach. A unique set of biological processes and candidate genes were identified specifically associated with changes in morphology and function of the head, skin and GI-tract. Transcriptome dynamics during metamorphosis were mapped with SOLiD sequencing of whole larvae and revealed greater than 8,000 differentially expressed (DE) genes significantly (p < 0.05) up- or down-regulated in comparison with the juvenile stage. Candidate transcripts quantified by SOLiD and qPCR analysis were significantly (r = 0.843; p < 0.05) correlated. The majority (98 %) of DE genes during metamorphosis were not TH-responsive. TH-responsive transcripts clustered into 6 groups based on their expression pattern during metamorphosis and the majority of the 145 DE TH-responsive genes were down-regulated. CONCLUSIONS A transcriptome resource has been generated for metamorphosing Atlantic halibut and over 8,000 DE transcripts per stage were identified. Unique sets of biological processes and candidate genes were associated with changes in the head, skin and GI-tract during metamorphosis. A small proportion of DE transcripts were TH-responsive, suggesting that they trigger gene networks, signalling cascades and transcription factors, leading to the overt changes in tissue occurring during metamorphosis.
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Affiliation(s)
- Ricardo N Alves
- Comparative Endocrinology and Integrative Biology Group, Centro de Ciências do Mar - CCMAR, University of Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Ana S Gomes
- Department of Biology, University of Bergen, 5020, Bergen, Norway
| | - Kurt Stueber
- Max Planck-Genome Centre, Max Planck-Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829, Köln, Germany
| | - Mbaye Tine
- Max Planck-Genome Centre, Max Planck-Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829, Köln, Germany.,Current address: Molecular Zoology Laboratory, Department of Zoology, University of Johannesburg, Auckland Park, 2006, South Africa
| | - M A S Thorne
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
| | | | - Richard Reinhard
- Max Planck-Genome Centre, Max Planck-Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829, Köln, Germany
| | - M S Clark
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
| | - Ivar Rønnestad
- Department of Biology, University of Bergen, 5020, Bergen, Norway
| | - Deborah M Power
- Comparative Endocrinology and Integrative Biology Group, Centro de Ciências do Mar - CCMAR, University of Algarve, Campus de Gambelas, 8005-139, Faro, Portugal.
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Aran RP, Steffen MA, Martin SD, Lopez OI, Bonett RM. Reduced effects of thyroid hormone on gene expression and metamorphosis in a paedomorphic plethodontid salamander. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2014; 322:294-303. [DOI: 10.1002/jez.b.22580] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 05/08/2014] [Indexed: 01/08/2023]
Affiliation(s)
- Robert P. Aran
- Department of Biological Science; University of Tulsa; Tulsa Oklahoma
| | | | - Samuel D. Martin
- Department of Biological Science; University of Tulsa; Tulsa Oklahoma
| | - Olivia I. Lopez
- Department of Biological Science; University of Tulsa; Tulsa Oklahoma
| | - Ronald M. Bonett
- Department of Biological Science; University of Tulsa; Tulsa Oklahoma
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Elinson RP, del Pino EM. Developmental diversity of amphibians. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2012; 1:345-69. [PMID: 22662314 PMCID: PMC3364608 DOI: 10.1002/wdev.23] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The current model amphibian, Xenopus laevis, develops rapidly in water to a tadpole which metamorphoses into a frog. Many amphibians deviate from the X. laevis developmental pattern. Among other adaptations, their embryos develop in foam nests on land or in pouches on their mother's back or on a leaf guarded by a parent. The diversity of developmental patterns includes multinucleated oogenesis, lack of RNA localization, huge non-pigmented eggs, and asynchronous, irregular early cleavages. Variations in patterns of gastrulation highlight the modularity of this critical developmental period. Many species have eliminated the larva or tadpole and directly develop to the adult. The wealth of developmental diversity among amphibians coupled with the wealth of mechanistic information from X. laevis permit comparisons that provide deeper insights into developmental processes.
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Affiliation(s)
- Richard P Elinson
- Department of Biological Sciences, Duquesne University, Pittsburgh, PA, USA.
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