Wnt/b-catenin signalling facilitates cell face decision-making in the early mouse embryo

Wnt/b-catenin signalling is a widespread cell signalling pathway with multiple roles during vertebrate development and disease. In mouse embryos stem cells (mESCs), there is a dual role for b-catenin: it promotes differentiation when activated as part of the Wnt/b-catenin signalling pathway and promotes stable pluripotency independently of signalling. The first requirement for Wnt/b-catenin signalling during mouse development has been reported at implantation. The relationship between b-catenin and pluripotency and that of mESCs cells with EPI progenitors suggests b-catenin has a functional role during preimplantation development.

We predict that active Wnt/b-catenin signalling is involved in the decision between developing into epiblast or primitive endoderm (PrE). Our preliminary results support that Wnt/b-catenin signalling promotes PrE differentiation in the mouse embryo. Our hypothesis will be addressed using a single cell quantitative approach to define the role of Wnt/b-catenin during PrE differentiation from 1-18 months. We will also elucidate the cellular mechanism by which b-catenin (Wnt/b-catenin) facilitates PrE differentiation from 18-24 months.

This study will have important implications for assisted reproduction and stem cell biology.