Embryonic stem cell-based in vitro models to study early mammalian development

Embryogenesis is a fascinating mystery. How a single fertilized egg, the zygote, reads out its genetic information and turns into a fully formed, multicellular organism still defies detailed understanding.
An adult organism can consist of trillions of cells of different types, organized to form various complex tissues and organs. To obtain such a system starting from a single cell requires an incredibly sophisticated combination of three key processes: cell division, differentiation and migration. Cell division turns a parent cell into two genetically identical copies, the daughter cells. Differentiation is the process by which a cell transforms into a particular cell type with a highly specialized function, such as a neuron, a bone cell or a muscle cell. While cells of different types have identical genomes, they express distinct sets of proteins that define the cells’ function and shape. Finally, directed cell migration is crucial to obtain proper three-dimensional organization and thereby correctly formed tissues and organs.

Over many decades, several model organisms have been used to study the development of insects (Drosophila), fish (Zebrafish), amphibians (Xenopus), avians (Chicken), and mammals (Mouse, Human). In this thesis, we present three studies of different stages of mammalian embryogenesis...