Description du sujet de thèse

Transposable elements (TEs) are defined as mobile genomic DNA sequences and are ubiquitous in all living organisms studied to date. These elements can constitute varying proportions of the organism's genome. Over long evolutionary periods, specific interactions between hosts and TEs have been selected to facilitate their coexistence, thus preventing the extinction of the host and/or the TE. In the germ line, the host has developed specific pathways to regulate TE expression, ensuring that their transposition remains compatible with the preservation of genome integrity, which will be passed on to the next generation. In the laboratory, our goal is to decipher the mechanisms used by TE families to colonise the genome. To explore these mechanisms, we activated transposable elements (TEs) and identified the different strategies they use to increase their copy number without compromising the integrity of the germline. To do this, we have developed a Drosophila melanogaster line that allows us to induce the mobility of different TE families and determine their integration sites using the pipeline we have established in the laboratory (TrEMOLO). In order to increase the number of TE copies in the genome, we applied our method over several generations. We demonstrated that five families of TEs belonging to the endogenous retrovirus group exhibit dynamic selection of their integration sites. In particular, for two of them (ZAM and gtwin), we showed that they have specific expression profiles and integration sites, thus limiting competition within the host genome. In addition, we established that their integration schedule varies during embryogenesis. The PhD student will work to identify and characterise the host proteins that have co-evolved with the parasitic genomes to ensure their stable coexistence. Deciphering the diversity of host-TE interactions that enable this coexistence is a key area of research, offering valuable insights into the biology of both the host and the genomic parasite represented by TEs.

Contexte de travail

The PhD student will work on a project based on a living model. Consequently, working hours will be adapted to the biological requirements and developmental stages of the model organism. The scientific environment at the Institute of Human Genetics is exceptional, offering access to cutting-edge technological platforms and services. The IHG is located on the Arnaud de Villeneuve campus, which is part of the Pro-Cycling Employer programme.