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Tolstenkov O, Mikhaleva Y, Glover JC. A miniaturized nigrostriatal-like circuit regulating locomotor performance in a protochordate. Curr Biol 2023; 33:3872-3883.e6. [PMID: 37643617 DOI: 10.1016/j.cub.2023.08.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 06/14/2023] [Accepted: 08/03/2023] [Indexed: 08/31/2023]
Abstract
To gain insight into the evolution of motor control systems at the origin of vertebrates, we have investigated higher-order motor circuitry in the protochordate Oikopleura dioica. We have identified a highly miniaturized circuit in Oikopleura with a projection from a single pair of dopaminergic neurons to a small set of synaptically coupled GABAergic neurons, which in turn exert a disinhibitory descending projection onto the locomotor central pattern generator. The circuit is reminiscent of the nigrostriatopallidal system in the vertebrate basal ganglia, in which disinhibitory circuits release specific movements under the modulatory control of dopamine. We demonstrate further that dopamine is required to optimize locomotor performance in Oikopleura, mirroring its role in vertebrates. A dopamine-regulated disinhibitory locomotor control circuit reminiscent of the vertebrate nigrostriatopallidal system was thus already present at the origin of ancestral chordates and has been maintained in the face of extreme nervous system miniaturization in the urochordate lineage.
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Affiliation(s)
- Oleg Tolstenkov
- Sars International Centre for Marine Molecular Biology, University of Bergen; Thormøhlensgate 55, 5008 Bergen, Norway
| | - Yana Mikhaleva
- Sars International Centre for Marine Molecular Biology, University of Bergen; Thormøhlensgate 55, 5008 Bergen, Norway
| | - Joel C Glover
- Sars International Centre for Marine Molecular Biology, University of Bergen; Thormøhlensgate 55, 5008 Bergen, Norway; Laboratory of Neural Development and Optical Recording (NDEVOR), Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Sognsvannsveien 9, 0372 Oslo, Norway.
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2
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Liu J, Gao S, Wei L, Xiong W, Lu Y, Song X, Zhang Y, Gao H, Li B. Choline acetyltransferase and vesicular acetylcholine transporter are required for metamorphosis, reproduction, and insecticide susceptibility in Tribolium castaneum. Gene 2022; 842:146794. [PMID: 35952841 DOI: 10.1016/j.gene.2022.146794] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 07/26/2022] [Accepted: 08/05/2022] [Indexed: 11/04/2022]
Abstract
Choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT) are essential enzymes for synthesizing and transporting acetylcholine (ACh). But their functions in metamorphosis, reproduction, and the insecticide susceptibility were poorly understood in the insects. To address these issues, we identified the orthologues of chat and vacht in Tribolium castaneum. Spatiotemporal expression profiling showed Chat has the highest expression at the early adult stage, while vacht shows peak expression at the early larval stage. Both of them were highly expressed at the head of late adult. RNA interference (RNAi) of chat and vacht both led to a decrease in ACh content at the late larval stage. It is observed that chat knockdown severely affected larval development and pupal eclosion, but vacht RNAi only disrupted pupal eclosion. Further, parental RNAi of chat or vacht led to 35 % or 30 % reduction in fecundity, respectively, and knockdown of them completely inhibited egg hatchability. Further analysis has confirmed that both the reduction in fecundity and hatchability caused through the maternal specificity in T. castaneum. Moreover, the transcript levels of chat and vacht were elevated after carbofuran or dichlorvos treatment. Reduction of chat or vacht decreased the resistance to carbofuran and dichlorvos. This study provides the evidence for chat and vacht not only involved in development and reproduction of insects but also could as the potential targets of insecticides.
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Affiliation(s)
- Juanjuan Liu
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Shanshan Gao
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China; College of Biology and Food Engineering, Anyang Institute of Technology, Anyang 455000, China
| | - Luting Wei
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Wenfeng Xiong
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Yaoyao Lu
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Xiaowen Song
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Yonglei Zhang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Han Gao
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Bin Li
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
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Post-gastrulation transition from whole-body to tissue-specific intercellular calcium signaling in the appendicularian tunicate Oikopleuradioica. Dev Biol 2022; 492:37-46. [PMID: 36162551 DOI: 10.1016/j.ydbio.2022.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 07/09/2022] [Accepted: 09/17/2022] [Indexed: 11/21/2022]
Abstract
We recently described calcium signaling in the appendicularian tunicate Oikopleura dioica during pre-gastrulation stages, and showed that regularly occurring calcium waves progress throughout the embryo in a characteristic spatiotemporal pattern from an initiation site in muscle lineage blastomeres (Mikhaleva et al., 2019). Here, we have extended our observations to the period spanning from gastrulation to post-hatching stages. We find that repetitive Ca2+ waves persist throughout this developmental window, albeit with a gradual increase in frequency. The initiation site of the waves shifts from muscle cells at gastrulation and early tailbud stages, to the central nervous system at late tailbud and post-hatching stages, indicating a transition from muscle-driven to neurally driven events as tail movements emerge. At these later stages, both the voltage gated Na + channel blocker tetrodotoxin (TTX) and the T-type Ca2+ channel blocker and nAChR antagonist mecamylamine eliminate tail movements. At late post-hatching stages, mecamylamine blocks Ca2+ signals in the muscles but not the central nervous system. Post-gastrulation Ca2+ signals also arise in epithelial cells, first in a haphazard pattern in scattered cells during tailbud stages, evolving after hatching into repetitive rostrocaudal waves with a different frequency than the nervous system-to-muscle waves, and insensitive to mecamylamine. The desynchronization of Ca2+ waves arising in different parts of the body indicates a shift from whole-body to tissue/organ-specific Ca2+ signaling dynamics as organogenesis occurs, with neurally driven Ca2+ signaling dominating at the later stages when behavior emerges.
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4
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Onuma TA, Nishida H. Developmental biology of the larvacean Oikopleura dioica: Genome resources, functional screening, and imaging. Dev Growth Differ 2021; 64:67-82. [PMID: 34964127 DOI: 10.1111/dgd.12769] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 12/13/2021] [Accepted: 12/13/2021] [Indexed: 12/01/2022]
Abstract
The larvacean Oikopleura dioica is a cosmopolitan planktonic chordate and is closely related to vertebrates. It is characterized by a tadpole-shaped morphology with notochord flanked by muscle in the tail and brain on the dorsal side, a short life cycle of five days, a compact genome of approximately 56 Mb, a simple and transparent body with a small number of cells (~4000 in functional juveniles), invariant embryonic cell lineages, and fast development that ensures complete morphogenesis and organ formation 10 h after fertilization. With these features, this marine chordate is a promising and advantageous animal model in which genetic manipulation is feasible. In this review, we introduce relevant resources and modern techniques that have been developed: (1) Genome and transcriptomes. Oikopleura dioica has the smallest genome among non-parasitic metazoans. Its genome databases have been generated using three geographically distant O. dioica populations, and several intra-species sequence differences are becoming evident; (2) Functional genetic knockdown techniques. Comprehensive screening of genes is feasible using ovarian microinjection and double-strand DNA-induced gene knockdown; and (3) Live imaging of embryos and larvae. Application of these techniques has uncovered novel aspects of development, including meiotic cell arrest, left-right patterning, epidermal cell patterning, and mouth formation involving the connection of ectoderm and endoderm sheets. Oikopleura dioca has become very useful for developmental and evolutionary studies in chordates.
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Affiliation(s)
- Takeshi A Onuma
- Graduate School of Science and Engineering, Faculty of Science, Kagoshima University, Kagoshima, Japan.,Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Hiroki Nishida
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan
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A chordate species lacking Nodal utilizes calcium oscillation and Bmp for left-right patterning. Proc Natl Acad Sci U S A 2020; 117:4188-4198. [PMID: 32029598 DOI: 10.1073/pnas.1916858117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Larvaceans are chordates with a tadpole-like morphology. In contrast to most chordates of which early embryonic morphology is bilaterally symmetric and the left-right (L-R) axis is specified by the Nodal pathway later on, invariant L-R asymmetry emerges in four-cell embryos of larvaceans. The asymmetric cell arrangements exist through development of the tailbud. The tail thus twists 90° in a counterclockwise direction relative to the trunk, and the tail nerve cord localizes on the left side. Here, we demonstrate that larvacean embryos have nonconventional L-R asymmetries: 1) L- and R-cells of the two-cell embryo had remarkably asymmetric cell fates; 2) Ca2+ oscillation occurred through embryogenesis; 3) Nodal, an evolutionarily conserved left-determining gene, was absent in the genome; and 4) bone morphogenetic protein gene (Bmp) homolog Bmp.a showed right-sided expression in the tailbud and larvae. We also showed that Ca2+ oscillation is required for Bmp.a expression, and that BMP signaling suppresses ectopic expression of neural genes. These results indicate that there is a chordate species lacking Nodal that utilizes Ca2+ oscillation and Bmp.a for embryonic L-R patterning. The right-side Bmp.a expression may have arisen via cooption of conventional BMP signaling in order to restrict neural gene expression on the left side.
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Almazán A, Ferrández-Roldán A, Albalat R, Cañestro C. Developmental atlas of appendicularian Oikopleura dioica actins provides new insights into the evolution of the notochord and the cardio-paraxial muscle in chordates. Dev Biol 2019; 448:260-270. [DOI: 10.1016/j.ydbio.2018.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/13/2018] [Accepted: 09/05/2018] [Indexed: 12/22/2022]
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Liu YS, Wang LF, Cheng XS, Huo YN, Ouyang XM, Liang LY, Lin Y, Wu JF, Ren JL, Guleng B. The pattern-recognition molecule mindin binds integrin Mac-1 to promote macrophage phagocytosis via Syk activation and NF-κB p65 translocation. J Cell Mol Med 2019; 23:3402-3416. [PMID: 30869196 PMCID: PMC6484411 DOI: 10.1111/jcmm.14236] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 01/23/2019] [Accepted: 01/31/2019] [Indexed: 12/31/2022] Open
Abstract
Mindin has a broad spectrum of roles in the innate immune system, including in macrophage migration, antigen phagocytosis and cytokine production. Mindin functions as a pattern‐recognition molecule for microbial pathogens. However, the underlying mechanisms of mindin‐mediated phagocytosis and its exact membrane receptors are not well established. Herein, we generated mindin‐deficient mice using the CRISPR‐Cas9 system and show that peritoneal macrophages from mindin‐deficient mice were severely defective in their ability to phagocytize E coli. Phagocytosis was enhanced when E coli or fluorescent particles were pre‐incubated with mindin, indicating that mindin binds directly to bacteria or non‐pathogen particles and promotes phagocytosis. We defined that 131I‐labelled mindin binds with integrin Mac‐1 (CD11b/CD18), the F‐spondin (FS)‐fragment of mindin binds with the αM‐I domain of Mac‐1 and that mindin serves as a novel ligand of Mac‐1. Blockade of the αM‐I domain of Mac‐1 using either a neutralizing antibody or si‐Mac‐1 efficiently blocked mindin‐induced phagocytosis. Furthermore, mindin activated the Syk and MAPK signalling pathways and promoted NF‐κB entry into the nucleus. Our data indicate that mindin binds with the integrin Mac‐1 to promote macrophage phagocytosis through Syk activation and NF‐κB p65 translocation, suggesting that the mindin/Mac‐1 axis plays a critical role during innate immune responses.
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Affiliation(s)
- Yuan-Sheng Liu
- Department of Gastroenterology, Zhongshan Hospital affiliated to Xiamen University, Xiamen, China.,The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Li-Fen Wang
- Department of Gastroenterology, Zhongshan Hospital affiliated to Xiamen University, Xiamen, China.,The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Xiao-Shen Cheng
- Department of Gastroenterology, Zhongshan Hospital affiliated to Xiamen University, Xiamen, China
| | - Ya-Ni Huo
- Department of Gastroenterology, Zhongshan Hospital affiliated to Xiamen University, Xiamen, China
| | - Xiao-Mei Ouyang
- Department of Gastroenterology, Zhongshan Hospital affiliated to Xiamen University, Xiamen, China
| | - Lai-Ying Liang
- Department of Gastroenterology, Zhongshan Hospital affiliated to Xiamen University, Xiamen, China
| | - Ying Lin
- Department of Gastroenterology, Zhongshan Hospital affiliated to Xiamen University, Xiamen, China
| | - Jian-Feng Wu
- State Key Laboratory of Cellular Stress Biology, School of life sciences, Xiamen University, Xiamen, China
| | - Jian-Lin Ren
- Department of Gastroenterology, Zhongshan Hospital affiliated to Xiamen University, Xiamen, China
| | - Bayasi Guleng
- Department of Gastroenterology, Zhongshan Hospital affiliated to Xiamen University, Xiamen, China.,State Key Laboratory of Cellular Stress Biology, School of life sciences, Xiamen University, Xiamen, China.,Faculty of Clinical Medicine & Institute of Microbial Ecology, Medical College of Xiamen University, Xiamen, China
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Ferrández-Roldán A, Martí-Solans J, Cañestro C, Albalat R. Oikopleura dioica: An Emergent Chordate Model to Study the Impact of Gene Loss on the Evolution of the Mechanisms of Development. Results Probl Cell Differ 2019; 68:63-105. [PMID: 31598853 DOI: 10.1007/978-3-030-23459-1_4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The urochordate Oikopleura dioica is emerging as a nonclassical animal model in the field of evolutionary developmental biology (a.k.a. evo-devo) especially attractive for investigating the impact of gene loss on the evolution of mechanisms of development. This is because this organism fulfills the requirements of an animal model (i.e., has a simple and accessible morphology, a short generation time and life span, and affordable culture in the laboratory and amenable experimental manipulation), but also because O. dioica occupies a key phylogenetic position to understand the diversification and origin of our own phylum, the chordates. During its evolution, O. dioica genome has suffered a drastic process of compaction, becoming the smallest known chordate genome, a process that has been accompanied by exacerbating amount of gene losses. Interestingly, however, despite the extensive gene losses, including entire regulatory pathways essential for the embryonic development of other chordates, O. dioica retains the typical chordate body plan. This unexpected situation led to the formulation of the so-called inverse paradox of evo-devo, that is, when a genetic diversity is able to maintain a phenotypic unity. This chapter reviews the biological features of O. dioica as a model animal, along with the current data on the evolution of its genes and genome. We pay special attention to the numerous examples of gene losses that have taken place during the evolution of this unique animal model, which is helping us to understand to which the limits of evo-devo can be pushed off.
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Affiliation(s)
- Alfonso Ferrández-Roldán
- Facultat de Biologia, Departament de Genètica, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Josep Martí-Solans
- Facultat de Biologia, Departament de Genètica, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Cristian Cañestro
- Facultat de Biologia, Departament de Genètica, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Ricard Albalat
- Facultat de Biologia, Departament de Genètica, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Catalonia, Spain.
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Mikhaleva Y, Skinnes R, Sumic S, Thompson EM, Chourrout D. Development of the house secreting epithelium, a major innovation of tunicate larvaceans, involves multiple homeodomain transcription factors. Dev Biol 2018; 443:117-126. [DOI: 10.1016/j.ydbio.2018.09.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/27/2018] [Accepted: 09/05/2018] [Indexed: 01/24/2023]
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10
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Lynagh T, Mikhaleva Y, Colding JM, Glover JC, Pless SA. Acid-sensing ion channels emerged over 600 Mya and are conserved throughout the deuterostomes. Proc Natl Acad Sci U S A 2018; 115:8430-8435. [PMID: 30061402 PMCID: PMC6099870 DOI: 10.1073/pnas.1806614115] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are proton-gated ion channels broadly expressed in the vertebrate nervous system, converting decreased extracellular pH into excitatory sodium current. ASICs were previously thought to be a vertebrate-specific branch of the DEG/ENaC family, a broadly conserved but functionally diverse family of channels. Here, we provide phylogenetic and experimental evidence that ASICs are conserved throughout deuterostome animals, showing that ASICs evolved over 600 million years ago. We also provide evidence of ASIC expression in the central nervous system of the tunicate, Oikopleura dioica Furthermore, by comparing broadly related ASICs, we identify key molecular determinants of proton sensitivity and establish that proton sensitivity of the ASIC4 isoform was lost in the mammalian lineage. Taken together, these results suggest that contributions of ASICs to neuronal function may also be conserved broadly in numerous animal phyla.
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Affiliation(s)
- Timothy Lynagh
- Department of Drug Design and Pharmacology, Center for Biopharmaceuticals, University of Copenhagen, 2100 Copenhagen, Denmark;
| | - Yana Mikhaleva
- Sars International Centre for Marine Molecular Biology, University of Bergen, 5006 Bergen, Norway
| | - Janne M Colding
- Department of Drug Design and Pharmacology, Center for Biopharmaceuticals, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Joel C Glover
- Sars International Centre for Marine Molecular Biology, University of Bergen, 5006 Bergen, Norway
- Department of Molecular Medicine, University of Oslo, 0372 Oslo, Norway
| | - Stephan A Pless
- Department of Drug Design and Pharmacology, Center for Biopharmaceuticals, University of Copenhagen, 2100 Copenhagen, Denmark
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Olsen LC, Kourtesis I, Busengdal H, Jensen MF, Hausen H, Chourrout D. Evidence for a centrosome-attracting body like structure in germ-soma segregation during early development, in the urochordate Oikopleura dioica. BMC DEVELOPMENTAL BIOLOGY 2018; 18:4. [PMID: 29486709 PMCID: PMC5830320 DOI: 10.1186/s12861-018-0165-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 02/16/2018] [Indexed: 11/27/2022]
Abstract
Background Germ cell formation has been investigated in sessile forms of tunicates. This process involves the release of a subset of maternal transcripts from the centrosome-attracting body (CAB) in the progenitor cells of the germ line. When germ-soma segregation is completed, CAB structures are missing from the newly formed primordial germ cells (PGCs). In free-swimming tunicates, knowledge about germ cell formation is lacking. In this investigation, comparative gene expression and electron microscopy studies were used to address germ cell formation in Oikopleura dioica (O. dioica). Results We found that the RNA localization pattern of pumilio (pum1) is similar to the pattern described for a subset of maternal transcripts marking the posterior end of ascidian embryos. Transcripts marking the posterior end are called postplasmic or posterior-end mark (PEM) transcripts. We found no localization of vasa (vas) transcripts to any sub-region within the germ-line precursor cells. Expression of vas4 was detected in the newly formed PGCs. Electron microscopy studies confirmed the presence of structures with similar morphology to CAB. In the same cytoplasmic compartment, we also identified pum1 transcripts and an epitope recognized by an antibody to histone H3 phosphorylated on serine 28. Conclusions Our findings support that a CAB-like structure participates in the segregation of maternal pum1 transcripts during germ-soma separation in O. dioica. Electronic supplementary material The online version of this article (10.1186/s12861-018-0165-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lisbeth Charlotte Olsen
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway. .,Department of Molecular Biology, University of Bergen, Thormöhlensgt 55, 5008, Bergen, Norway. .,Department of Biological Sciences, University of Bergen, Thormöhlensgt 55, 5008, Bergen, Norway.
| | - Ioannis Kourtesis
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Henriette Busengdal
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Marit Flo Jensen
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Harald Hausen
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | - Daniel Chourrout
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
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12
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Roles of Retinoic Acid Signaling in Shaping the Neuronal Architecture of the Developing Amphioxus Nervous System. Mol Neurobiol 2017; 55:5210-5229. [PMID: 28875454 DOI: 10.1007/s12035-017-0727-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/08/2017] [Indexed: 02/01/2023]
Abstract
The morphogen retinoic acid (RA) patterns vertebrate nervous systems and drives neurogenesis, but how these functions evolved remains elusive. Here, we show that RA signaling plays stage- and tissue-specific roles during the formation of neural cell populations with serotonin, dopamine, and GABA neurotransmitter phenotypes in amphioxus, a proxy for the ancestral chordate. Our data suggest that RA signaling restricts the specification of dopamine-containing cells in the ectoderm and of GABA neurons in the neural tube, probably by regulating Hox1 and Hox3 gene expression, respectively. The two Hox genes thus appear to serve distinct functions rather than to participate in a combinatorial Hox code. We were further able to correlate the RA signaling-dependent mispatterning of hindbrain GABA neurons with concomitant motor impairments. Taken together, these data provide new insights into how RA signaling and Hox genes contribute to nervous system as well as to motor control development in amphioxus and hence shed light on the evolution of these functions within vertebrates.
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Abstract
The Genetics Society of America’s George W. Beadle Award honors individuals who have made outstanding contributions to the community of genetics researchers and who exemplify the qualities of its namesake as a respected academic, administrator, and public servant. The 2015 recipient is John Postlethwait. He has made groundbreaking contributions in developing the zebrafish as a molecular genetic model and in understanding the evolution of new gene functions in vertebrates. He built the first zebrafish genetic map and showed that its genome, along with that of distantly related teleost fish, had been duplicated. Postlethwait played an integral role in the zebrafish genome-sequencing project and elucidated the genomic organization of several fish species. Postlethwait is also honored for his active involvement with the zebrafish community, advocacy for zebrafish as a model system, and commitment to driving the field forward.
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