Cell migration is a crucial biological process during development, homeostasis and disease. In order to migrate, cells need to polarise. They have to form a leading edge that pushes the cell forward and a cell rear that retracts. To study cell polarisation during migration in an in vivo context, we employ zebrafish primordial germ cells (PGCs) as a model. In my project, my aim is to understand how the cells become polarised while migrating through developing tissues in the live embryo. Specifically, to identify the different structures and proteins that are polarised and the mechanism that leads to polarity. Additionally, I try to understand how the interactions with other cell types affect the polarisation of PGCs.