Keisuke Sako         Verena Ruprecht           Stefan Wieser


During zebrafish gastrulation, large populations of germ layer progenitor cells migrate from the place they are born to the position within the embryo from where they will form tissue and organs. We are analyzing the molecular and cellular mechanisms by which mesoderm and endoderm progenitor cells migrate from the germ ring margin toward the forming embryonic axis. Specifically, we are asking how cell adhesion and actomyosin contractility control progenitor cell polarization and directional migration. In order to address these questions, we are establishing cell culture assays to mimic directional migration of primary progenitor cells in culture and analyze progenitor cell migration within the gastrulating embryo using various microscopy techniques, such as multi-photon  and fast-scanning microscopy.









Dorsal view of two cells of the prospective neurectoderm in a living wild-type zebrafish embryo during gastrulation. The cells were labelled with a mixture of cytosolic and membrane-bound GFP, and visualised by multi-photon confocal microscopy.

Time-lapse movie of the cell movements within the germ ring margin at
the region of the shield from shield stage (60% epiboly, 6 hpf) onwards.
The movie was recorded for a total of 123 min in 2.6 min time intervals. Sagittal views.

Protrusion formation and migration of wild-type prechordal plate progenitors.
Animal view of the leading edge of the prechordal plate of a wild-type embryo.
Plasma membrane (GPI-RFP) is red; actin cortex (Lifeact-GFP) is green.
Scale bar = 10 µm. Time in min:sec.