Ecole Doctorale COMPLEXITE DU VIVANT – Fiche Projet CONCOURS
Nom et prénom du directeur de thèse : Houliston Evelyn
Coordonnées
Tel : +33 (0) 4 93 76 39 83
e-mail : houliston@obs-vlfr.
Nom et prénom du co-encadrant (non HdR) : Leclère Lucas
Coordonnées
Tel : +33 (0) 4 93 76 37 94
e-mail : [email protected]
Y-a-t-il un candidat déjà identifié pour le projet : OUI
Nom et prénom du responsable de l’équipe : Houliston Evelyn
Intitulé de l'équipe : Cnidarian developmental mechanisms
Nombre de chercheurs et enseignants-chercheurs statutaires de l’équipe titulaires d’une HDR (ou équivalent) : 1
Nom et prénom du responsable d'unité ou de département : Houliston Evelyn
Intitulé et N° d’unité ou de département :
UMR7009 CNRS/UPMC – Laboratoire de Biologie du Développement de Villefranche sur mer.
Signature du directeur d'unité ou de département (vaut avis favorable pour le dépôt du projet) :
Titre du projet de thèse : Embryonic developmental mechanisms in the direct developing jellyfish Pelagia.
Spécialité : Biologie du développement, Evolution
Résumé du projet de thèse (1 page maximum, en anglais)
Cnidarians (including coral, sea anemone, jellyfish) are sister group to Bilateria (which includes most experimental
animal model species) but employ a largely overlapping set of developmental regulator genes, and thus can provide extremely
informative comparative systems for understanding developmental mechanisms and their evolution (Houliston et al 2010).
Current knowledge on developmental regulator genes from the vast cnidarian clade is restricted to very few species and is
thus largely inadequate to address the evolution of embryonic developmental mechanisms within it, or to make comparisons
with Bilateria. Concretely, the few cnidarian developmental model species developed so far represent only two of the main
cnidarian sub-groups: the anthozoans (sea anemone Nematostella and coral Acropora) and the hydrozoans (Clytia, Hydra and
Hydractinia), while the molecular regulation of embryonic development in the scyphozoan group, the "true jellyfish",
remains completely unexplored. In this context, we have started to develop tools to exploit the direct-developing scyphozoan
Pelagia noctiluca as an experimental model.
This PhD project will analyze the involvement of conserved developmental regulator genes during embryonic
development, leading to formation of the juvenile jellyfish (ephrya) of Pelagia. Embryonic development in Pelagia is direct,
the planula larvae transforming four days after fertilization into the ephrya, which already exhibits the radial adult body plan.
Pelagia medusae are very abundant in the bay of Villefranche-sur-mer throughout the year, a large numbers of eggs and
synchronized embryonic stages can be obtained daily, and the simplified life cycle can be controlled in the lab. Some genetic
resources, tools and methods are already established for Pelagia, and will be further developed in the framework of this
project. Studies currently underway have uncovered a wide set of developmental regulators, similar to those in Nematostella
and Clytia.
The goal of this project is to analyze the sets of genes expressed during successive stages of development from blastula
to ephyra in Pelagia, and to characterize in detail the roles of key selected genes. Specific comparisons will be made with the
embryonic developmental mechanisms previously characterized in Nematostella and Clytia (e.g. Leclère et al. 2014, 2016;
Lapebie et al. 2014). Preliminary data have identified promising candidate developmental regulators including Wnt signaling
ligands, as well as transcription factors of the Six and Fox families, expressed at the ephyra stage. This molecular study will
be complemented by a precise morphological description of the developmental stages from egg to ephyra. The PhD student
will employ a variety of techniques including molecular biology, imaging, transcriptomic analyses and gene function analyses
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Ecole Doctorale COMPLEXITE DU VIVANT – Fiche Projet CONCOURS
and will also participate in developing new tools for studying cell and developmental biology of Pelagia.
Experimental strategy:
1) Establish the gene repertoire of Pelagia noctiluca using both existing and newly generated transcriptomic data and
phylogenetic methods, focusing on well conserved signaling pathway components (e.g. Wnt, BMP, FGF) and transcription
factors (e.g. Fox, Sox, Homeobox).
2) Undertake expression profiling by in situ hybridization for a selection of genes identified in (1). Particular attention will be
paid to genes whose orthologs in Nematostella and Clytia have well-described expression patterns and known functions.
3) Characterize at the cellular level the main developmental stages from egg to ephyra in relation to the gene expression
patterns established in (2). Cell proliferation, cell movement and tissue organization will be detailed at gastrula, planula,
metamorphosing planula and ephyra stages using a variety of approaches including imaging (live and fixed specimens) and
different types of nuclear, cytoplasmic and membrane staining.
4) Perform knockdown assays on key genes identified from (1 & 2) and showing particularly interesting expression patterns.
Knockdown will be performed by injecting morpholino and/or RNAi in unfertilized eggs. Likely candidates include Wnt βcatenin signaling pathway components, since a wealth of functional data demonstrate a major role of this pathway in embryo
patterning in all other cnidarian (e.g. Leclère et al. 2016; Lapebie et al. 2014) as well as bilaterian developmental models.
Thèses actuellement en cours dans l’équipe.
ED
Financement
Quiroga Artigas Gonzalo
Nom et Prénom du doctorant
Houliston Evelyn
Directeur(s) de thèse
2013
Année de 1ère inscription
CdV
Peron Sophie
Houliston Evelyn
Co-encadrant : Leclère L.
2015
CdV
Marie Curie – ITN network
(soutenance : mai 2016)
MRT
Trois publications récentes du directeur de thèse et du co-encadrant.
Directeur de thèse :
Leclère L, Copley RR, Momose T, Houliston E. 2016. Hydrozoan insights in animal development and evolution. Current
Opinion Genetics & Development. 39:157-167.
Lapébie P, Ruggiero A, Barreau C, Chevalier S, Chang P, Dru P, Houliston E, Momose T. 2014. Differential responses to
Wnt and PCP disruption predict expression and developmental function of conserved and novel genes in a cnidarian.
PLoS Genetics. 10(9):e1004590.
Houliston E, Momose T, Manuel M. 2010. Clytia hemisphaerica: a jellyfish cousin joins the laboratory. Trends in Genetics
26(4):159-67.
Co-encadrant :
Leclère L, Röttinger E. 2017. Diversity of Cnidarian Muscles: Function, Anatomy, Development and Regeneration.
Frontiers in Cell and Developmental Biology. 4:157.
Leclère L, Bause M, Sinigaglia C, Steger J, Rentzsch F. 2016. Development of the aboral domain in Nematostella requires
β-catenin and the opposing activities of six3/6 and frizzled5/8. Development. 143(10):1766-1777.
Leclère L, Rentzsch F. 2014. RGM regulates BMP-mediated secondary axis formation in the sea anemone Nematostella
vectensis. Cell Reports 9(5):1921-30.
Docteurs encadrés par le directeur de thèse ayant soutenu après septembre 2011 et publications relatives à leur sujet de thèse.
Nom : Fourrage Cécile. Durée de thèse : 39 mois, oct. 2007- déc. 2012. Ecole Doctorale : Diversité du Vivant.
Fourrage C, Swann K, Gonzalez Garcia R, Campbell AK, Houliston E. 2014. Endogenous GFPs and photoproteins
expressed in eggs of the jellyfish Clytia hemisphaerica localise to mitochondria and show efficient
bioluminescence energy transfer. Open Biology 9;4:130206.
Fourrage C, Chevalier S, Houliston E. 2011. A highly conserved Poc1 protein characterized in embryos of the
hydrozoan Clytia hemisphaerica: localization and functional studies. PLoS One 5(11):e13994.
Nom : Antonella Ruggiero. Durée de thèse : 48 mois, oct. 2011-sept. 2015. Ecole Doctorale : Complexité du Vivant.
Lapébie P, Ruggiero A, Barreau C, Chevalier S, Chang P, Dru P, Houliston E, Momose T. 2014. Differential
responses to Wnt and PCP disruption predict expression and developmental function of conserved and novel
genes in a cnidarian. PLoS Genetics. 10(9):e1004590.
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