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Lanoizelet M, Elkhoury Youhanna C, Roure A, Darras S. Molecular control of cellulosic fin morphogenesis in ascidians. BMC Biol 2024; 22:74. [PMID: 38561802 PMCID: PMC10986139 DOI: 10.1186/s12915-024-01872-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 03/20/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND The tunicates form a group of filter-feeding marine animals closely related to vertebrates. They share with them a number of features such as a notochord and a dorsal neural tube in the tadpole larvae of ascidians, one of the three groups that make tunicates. However, a number of typical chordate characters have been lost in different branches of tunicates, a diverse and fast-evolving phylum. Consequently, the tunic, a sort of exoskeleton made of extracellular material including cellulose secreted by the epidermis, is the unifying character defining the tunicate phylum. In the larva of ascidians, the tunic differentiates in the tail into a median fin (with dorsal and ventral extended blades) and a caudal fin. RESULTS Here we have performed experiments in the ascidian Phallusia mammillata to address the molecular control of tunic 3D morphogenesis. We have demonstrated that the tail epidermis medio-lateral patterning essential for peripheral nervous system specification also controls tunic elongation into fins. More specifically, when tail epidermis midline identity was abolished by BMP signaling inhibition, or CRISPR/Cas9 inactivation of the transcription factor coding genes Msx or Klf1/2/4/17, median fin did not form. We postulated that this genetic program should regulate effectors of tunic secretion. We thus analyzed the expression and regulation in different ascidian species of two genes acquired by horizontal gene transfer (HGT) from bacteria, CesA coding for a cellulose synthase and Gh6 coding for a cellulase. We have uncovered an unexpected dynamic history of these genes in tunicates and high levels of variability in gene expression and regulation among ascidians. Although, in Phallusia, Gh6 has a regionalized expression in the epidermis compatible with an involvement in fin elongation, our functional studies indicate a minor function during caudal fin formation only. CONCLUSIONS Our study constitutes an important step in the study of the integration of HGT-acquired genes into developmental networks and a cellulose-based morphogenesis of extracellular material in animals.
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Affiliation(s)
- Maxence Lanoizelet
- Sorbonne Université, CNRS, Biologie Intégrative Des Organismes Marins (BIOM), Banyuls/Mer, 66650, France.
- Present address: Laboratory of Developmental Neurobiology, Department of Biology, KU Leuven, Louvain, Belgium.
| | - Christel Elkhoury Youhanna
- Sorbonne Université, CNRS, Biologie Intégrative Des Organismes Marins (BIOM), Banyuls/Mer, 66650, France
- Present address: Centre de Biologie Structurale, Univ Montpellier, CNRS UMR 5048, INSERM U1054, Montpellier, 34090, France
| | - Agnès Roure
- Sorbonne Université, CNRS, Biologie Intégrative Des Organismes Marins (BIOM), Banyuls/Mer, 66650, France
| | - Sébastien Darras
- Sorbonne Université, CNRS, Biologie Intégrative Des Organismes Marins (BIOM), Banyuls/Mer, 66650, France.
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Daric V, Lanoizelet M, Mayeur H, Leblond C, Darras S. Genomic Resources and Annotations for a Colonial Ascidian, the Light-Bulb Sea Squirt Clavelina lepadiformis. Genome Biol Evol 2024; 16:evae038. [PMID: 38441487 PMCID: PMC10950049 DOI: 10.1093/gbe/evae038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/23/2024] [Indexed: 03/20/2024] Open
Abstract
Ascidian embryos have been studied since the birth of experimental embryology at the end of the 19th century. They represent textbook examples of mosaic development characterized by a fast development with very few cells and invariant cleavage patterns and lineages. Ascidians belong to tunicates, the vertebrate sister group, and their study is essential to shed light on the emergence of vertebrates. Importantly, deciphering developmental gene regulatory networks has been carried out mostly in two of the three ascidian orders, Phlebobranchia and Stolidobranchia. To infer ancestral developmental programs in ascidians, it is thus essential to carry out molecular embryology in the third ascidian order, the Aplousobranchia. Here, we present genomic resources for the colonial aplousobranch Clavelina lepadiformis: a transcriptome produced from various embryonic stages, and an annotated genome. The assembly consists of 184 contigs making a total of 233.6 Mb with a N50 of 8.5 Mb and a L50 of 11. The 32,318 predicted genes capture 96.3% of BUSCO orthologs. We further show that these resources are suitable to study developmental gene expression and regulation in a comparative framework within ascidians. Additionally, they will prove valuable for evolutionary and ecological studies.
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Affiliation(s)
- Vladimir Daric
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins (BIOM), F-66650 Banyuls/Mer, France
| | - Maxence Lanoizelet
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins (BIOM), F-66650 Banyuls/Mer, France
| | - Hélène Mayeur
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins (BIOM), F-66650 Banyuls/Mer, France
| | - Cécile Leblond
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins (BIOM), F-66650 Banyuls/Mer, France
| | - Sébastien Darras
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins (BIOM), F-66650 Banyuls/Mer, France
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Mayeur H, Lanoizelet M, Quillien A, Menuet A, Michel L, Martin KJ, Dejean S, Blader P, Mazan S, Lagadec R. When Bigger Is Better: 3D RNA Profiling of the Developing Head in the Catshark Scyliorhinus canicula. Front Cell Dev Biol 2021; 9:744982. [PMID: 34746140 PMCID: PMC8569936 DOI: 10.3389/fcell.2021.744982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/28/2021] [Indexed: 11/13/2022] Open
Abstract
We report the adaptation of RNA tomography, a technique allowing spatially resolved, genome-wide expression profiling, to a species occupying a key phylogenetic position in gnathostomes, the catshark Scyliorhinus canicula. We focused analysis on head explants at an embryonic stage, shortly following neural tube closure and of interest for a number of developmental processes, including early brain patterning, placode specification or the establishment of epithalamic asymmetry. As described in the zebrafish, we have sequenced RNAs extracted from serial sections along transverse, horizontal and sagittal planes, mapped the data onto a gene reference taking advantage of the high continuity genome recently released in the catshark, and projected read counts onto a digital model of the head obtained by confocal microscopy. This results in the generation of a genome-wide 3D atlas, containing expression data for most protein-coding genes in a digital model of the embryonic head. The digital profiles obtained for candidate forebrain regional markers along antero-posterior, dorso-ventral and left-right axes reproduce those obtained by in situ hybridization (ISH), with expected relative organizations. We also use spatial autocorrelation and correlation as measures to analyze these data and show that they provide adequate statistical tools to extract novel expression information from the model. These data and tools allow exhaustive searches of genes exhibiting any predefined expression characteristic, such a restriction to a territory of interest, thus providing a reference for comparative analyses across gnathostomes. This methodology appears best suited to species endowed with large embryo or organ sizes and opens novel perspectives to a wide range of evo-devo model organisms, traditionally counter-selected on size criterion.
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Affiliation(s)
- Hélène Mayeur
- CNRS, Sorbonne Université, UMR 7232-Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, Banyuls sur Mer, France
| | - Maxence Lanoizelet
- CNRS, Sorbonne Université, UMR 7232-Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, Banyuls sur Mer, France
| | - Aurélie Quillien
- Molecular, Cellular and Developmental Biology (MCD UMR 5077), Centre de Biologie Intégrative (CBI, FR 3743), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Arnaud Menuet
- UMR 7355, Experimental and Molecular Immunology and Neurogenetics, CNRS and University of Orléans, Orléans, France
| | - Léo Michel
- CNRS, Sorbonne Université, UMR 7232-Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, Banyuls sur Mer, France
| | - Kyle John Martin
- United Kingdom Research and Innovation, Biotechnology and Biological Sciences Research Council, Swindon, United Kingdom
| | - Sébastien Dejean
- Institut de Mathématiques de Toulouse, Université de Toulouse, CNRS, UPS, UMR 5219, Toulouse, France
| | - Patrick Blader
- Molecular, Cellular and Developmental Biology (MCD UMR 5077), Centre de Biologie Intégrative (CBI, FR 3743), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Sylvie Mazan
- CNRS, Sorbonne Université, UMR 7232-Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, Banyuls sur Mer, France
| | - Ronan Lagadec
- CNRS, Sorbonne Université, UMR 7232-Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, Banyuls sur Mer, France
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Docampo-Seara A, Lanoizelet M, Lagadec R, Mazan S, Candal E, Rodríguez MA. Mitral cell development in the olfactory bulb of sharks: evidences of a conserved pattern of glutamatergic neurogenesis. Brain Struct Funct 2019; 224:2325-2341. [PMID: 31203451 PMCID: PMC6698271 DOI: 10.1007/s00429-019-01906-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 06/07/2019] [Indexed: 12/18/2022]
Abstract
In mammals, the development of the olfactory bulb (OB) relies in part on the expression of transcription factors involved in the specifications/differentiation of glutamatergic cells. In a previous study from our group, a high molecular similarity was reported between mammals and cartilaginous fishes regarding the neurogenic mechanisms underlying the development of glutamatergic cells in the telencephalon. However, information about the transcriptional program operating in the development of the glutamatergic system (mainly represented by mitral cells) in the OB is lacking in the catshark Scyliorhinus canicula, a cartilaginous fish. Using immunohistochemistry and in situ hybridization techniques, we have found that, previously to the appearance of the olfactory primordium (OP), proliferating cells expressing Pax6 with molecular hallmarks of progenitor radial glia were located in the ventrolateral pallial ventricular zone. Later in development, when the OP is recognizable, a stream of Pax6-positive cells were observed between the ventricular zone and the OP, where transcription factors involved in mitral cell development in mammals (ScTbr2, ScNeuroD, Tbr1) are expressed. Later in development, these transcription factors became expressed in a layered-like structure where ScVglut1, a marker of mitral cells, is also present. Our data suggest that the transcriptional program related with the specification/differentiation of glutamatergic cells in the telencephalon has been conserved throughout the evolution of vertebrates. These results, in combination with previous studies concerning GABAergic neurogenesis in sharks, have evidenced that the OB of mammals and sharks shares similarities in the timing and molecular programs of development.
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Affiliation(s)
- A Docampo-Seara
- Departamento de Bioloxía Funcional, Centro de Investigación en Bioloxía (CIBUS), Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Spain
| | - M Lanoizelet
- CNRS, Sorbonne Universités, UPMC Univ Paris 06, UMR7232, Observatoire Océanologique, Banyuls sur Mer, France
| | - R Lagadec
- CNRS, Sorbonne Universités, UPMC Univ Paris 06, UMR7232, Observatoire Océanologique, Banyuls sur Mer, France
| | - S Mazan
- CNRS, Sorbonne Universités, UPMC Univ Paris 06, UMR7232, Observatoire Océanologique, Banyuls sur Mer, France
| | - E Candal
- Departamento de Bioloxía Funcional, Centro de Investigación en Bioloxía (CIBUS), Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Spain
| | - M A Rodríguez
- Departamento de Bioloxía Funcional, Centro de Investigación en Bioloxía (CIBUS), Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Spain.
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