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> Stages de M2 > Liste des stages proposés pour l’année 2012-2013. > Ontogenèse des cellules germinales primordiales

Ontogenèse des cellules germinales primordiales

proposé par Stéphane Viville, CNRS, INSERM - Illkirch (67)

Title : Role of Tex19 in retrotransposons silencing during spermatogenesis. Mammalian germ cells progress through a unique developmental program that includes : proliferation and migration of the nascent primordial germ cell (PGC) population, acquisition of totipotency through a nuclear DNA reprogramming process, resetting new imprinted marks and differentiation to mature gametes. This reprogramming process involves a reexpression, mainly in male gonads, of transposable elements (TE), which need to be tightly controlled. We previously characterized Tex19.1 as a mammalian specific protein with a restricted expression in pluripotent stem cells and germ line (Kuntz et al Stem cell 2008). Bioinformatic alignment shows two unknown well conserved domain between mammals and which function remains unclear. Tex19 is duplicated in mice and rats. We named them Tex19.1 and Tex19.2. Tex19.1 expression is restricted to embryonic stem cells (ESC) and the germ line while Tex19.2 is mainly expressed in somatic cells in gonads. We generated Tex19.1 and Tex19.2 knockout mice on one hand and the double knockout for both genes on the other hand. We confirmed already published results for Tex19.1 but we still do not know the exact function of Tex19 protein especially during the PGC and ESC establishment. So for this purpose, the main aim of our future work is to first identify the Tex19 protein partners by the GST pulldown and the co immunoprecipitation techniques. As we already suspect an interesting role of Tex19 during the silencing of the TE essentially important for spermatogenesis, we would also like to perform an immunohistochemical (IHC) analysis of several proteins implicated in the regulation of retrotransposon expression in testes and in primordial germ cells. The IHC analysis will be done on isolated PGCs from gonads of Oct4-GFP mice and on sections from testes collected in our mutant TEX19.1 and TEX19.2 mice.

Expected assessments : theoretical and practical skills in developmental, cellular and molecular biology. We also seek for motivation, strictness and hardworking person able to integrate our team.

Assessments acquired during the internship : Good management of the project, Bibliographic study, and critical analysis of the results.

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