{"id":3545,"date":"2014-07-28T13:27:40","date_gmt":"2014-07-28T12:27:40","guid":{"rendered":"https:\/\/www.egce.universite-paris-saclay.fr\/?p=3545"},"modified":"2014-07-28T13:27:40","modified_gmt":"2014-07-28T12:27:40","slug":"stage-elegem","status":"publish","type":"post","link":"https:\/\/www.egce.universite-paris-saclay.fr\/?p=3545","title":{"rendered":"Interactions Wolbachia\/\u00c9l\u00e9ments transposables chez la Drosophile"},"content":{"rendered":"

Nom de l’\u00e9quipe d’accueil<\/strong>
\nEl\u00e9ments G\u00e9n\u00e9tiques Mobiles<\/p>\n

Responsable<\/strong>
\nPierre Capy, Aur\u00e9lie Hua-Van<\/p>\n

Profil du candidat<\/strong>
\nInt\u00e9ress\u00e9(e) par l’\u00e9volution du g\u00e9nome, les endosymbioses et les interactions entre entit\u00e9s g\u00e9n\u00e9tiques partageant la m\u00eame niche \u00e9cologique: la cellule<\/p>\n

Descriptif du stage<\/strong><\/p>\n

Ce stage s\u2019inscrit dans les th\u00e9matiques d\u00e9velopp\u00e9es depuis plusieurs ann\u00e9es dans l\u2019\u00e9quipe sur l\u2019\u00e9volution de l\u2019activit\u00e9 et de la r\u00e9gulation des \u00e9l\u00e9ments transposables (ET) chez la drosophile.<\/p>\n

Les ET sont pr\u00e9sents dans tous les g\u00e9nomes, o\u00f9 ils se d\u00e9placent et s\u2019amplifient, jusqu\u2019\u00e0 parfois en constituer la plus grande partie. En se multipliant dans le g\u00e9nome, ils sont transmis aux descendants de mani\u00e8re non-mendelienne, et peuvent ainsi se propager rapidement dans la population: ce sont des parasites sexuels. La transposition est cependant \u00e9troitement contr\u00f4l\u00e9e, en particulier dans la lign\u00e9e germinale, par des m\u00e9canismes faisant intervenir des petits ARNs. Chez la drosophile, cette voie de r\u00e9gulation implique des prot\u00e9ines Argonaute<\/em> telles que PIWI, AUB, AGO3, agissant dans le noyau ou dans une sous-structure cytoplasmique (le nuage) \u00e9troitement associ\u00e9e aux mitochondries. Une r\u00e9gulation est aussi \u00e0 l\u2019\u0153uvre dans les cellules somatiques, impliquant la prot\u00e9ine AGO2. Ces m\u00e9canismes de silencing<\/em> sont parfois perturb\u00e9s, par exemple suite \u00e0 des stress biotiques ou abiotiques qui peuvent ainsi conduire \u00e0 une r\u00e9activation des \u00e9l\u00e9ments.<\/p>\n

Au niveau des gonades et du cerveau, chez les insectes, les \u00e9l\u00e9ments transposables partagent les cellules avec des endosymbiontes, se comportant, tout comme les \u00e9l\u00e9ments transposables, comme des parasites ou des mutualistes. Il s\u2019agit de la bact\u00e9rie Wolbachia<\/em>, qui manipule la reproduction sexu\u00e9e de son h\u00f4te afin de favoriser sa propre transmission et d\u2019envahir ainsi rapidement les populations. Cette manipulation passe par des perturbations de la spermatogen\u00e8se (Wolbachia<\/em> dans les gonades) ou par des modifications du comportement des femelles (Wolbachia<\/em> dans le cerveau). Plusieurs \u00e9tudes r\u00e9centes indiquent que les Wolbachia<\/em> interf\u00e8rent avec les voies de petits ARNs, en modifiant l\u2019expression des prot\u00e9ines Argonaute<\/em>. Elles semblent aussi impliqu\u00e9es dans des stress oxydatifs, en lien direct ou indirect avec les mitochondries, avec lesquelles elles entretiennent des interactions physiques \u00e9troites. Ainsi, ces donn\u00e9es sugg\u00e8rent qu\u2019elles pourraient interf\u00e9rer dans l\u2019expression et la r\u00e9gulation des \u00e9l\u00e9ments transposables.<\/p>\n

L\u2019objectif du stage est d\u2019\u00e9valuer l\u2019importance des interactions entre Wolbachia<\/em> et les \u00e9l\u00e9ments transposables, dans deux esp\u00e8ces de drosophiles\u00a0: D. melanogaster<\/em> et son esp\u00e8ce s\u0153ur D. simulans<\/em>. Pour cela, nous g\u00e9nererons des lign\u00e9es de Drosophile infect\u00e9es ou non par des Wolbachia<\/em>, par traitement antibiotique de souches naturellement infect\u00e9es. Nous \u00e9valuerons l\u2019expression de deux \u00e9l\u00e9ments transposables (mos1<\/em>, et gypsy<\/em>) dans les gonades, et le cerveau, par RT-qPCR sur des ARNm extraits de ces deux tissus, \u00e0 diff\u00e9rents stades de d\u00e9veloppement (larves de stade III et adultes ag\u00e9s de 5 jours), chez les m\u00e2les et les femelles. En parall\u00e8le, des hybridations in situ<\/em> et des immunomarquages seront r\u00e9alis\u00e9s sur ces organes, permettant de comparer la localisation histologique des ARNm des \u00e9l\u00e9ments transposables, des prot\u00e9ines AGO et des endosymbiontes Wolbachia<\/em>.<\/p>\n

R\u00e9f\u00e9rences<\/strong><\/p>\n

Hua-Van A, Le Rouzic A, Boutin TS, Fil\u00e9e J, Capy P. 2011. The struggle for life of the genome’s selfish architects. Biol Direct 6:19.<\/p>\n

Picot S, Wallau GL, Loreto EL, Heredia FO, Hua-Van A, Capy P. 2008. The mariner<\/em> transposable element in natural populations of Drosophila simulans<\/em>. Heredity (Edinb) 101:53-59.<\/p>\n

Wallau GL, Hua-Van A, Capy P, Loreto EL. 2011. The evolutionary history of mariner<\/em>-like elements in Neotropical drosophilids. Genetica 139:327-338.<\/p>\n

Mots clefs<\/strong>
\n\u00e9volution, \u00e9l\u00e9ments transposables, wolbachia, drosophila, interaction, r\u00e9gulation<\/p>\n

Contact<\/strong>
\naurelie.hua-van@universite-paris-saclay.fr<\/p>\n

Date de validit\u00e9<\/strong>
\njanvier 2015<\/p>\n

Dur\u00e9e (mois)<\/strong>
\n6 mois (M2)<\/p>\n","protected":false},"excerpt":{"rendered":"

Nom de l’\u00e9quipe d’accueil El\u00e9ments G\u00e9n\u00e9tiques Mobiles Responsable Pierre Capy, Aur\u00e9lie Hua-Van Profil du candidat Int\u00e9ress\u00e9(e) par l’\u00e9volution du g\u00e9nome, les endosymbioses et les interactions entre entit\u00e9s g\u00e9n\u00e9tiques partageant la m\u00eame niche \u00e9cologique: la cellule Descriptif du stage Ce stage s\u2019inscrit dans les th\u00e9matiques d\u00e9velopp\u00e9es depuis plusieurs ann\u00e9es dans l\u2019\u00e9quipe sur l\u2019\u00e9volution de l\u2019activit\u00e9 et […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center 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