A truly mind-boggling process, embryonic development sees a single cell give rise to a complex organism, with a multitude of different tissue types. To form 3D structures like our organs, cells must first re-arrange themselves into hollow spheres or tubes, a critical event known as cavitation. Embryonic stem cells can do this in the laboratory, allowing researchers to study how this phenomenon is triggered and controlled. Correct cavitation requires cell polarity, meaning that the various molecules and structures inside the cells must be unequally arranged, so one side of the cell differs from the other; those above (in blue), which have self-organised to form a hollow shape, are enriched in certain proteins on the inside (in red) and others on the outside edge (in green). Recent work is beginning to identify the proteins responsible for this internal re-arrangement, sending, receiving and responding to polarity signals from neighbours to coordinate development.
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.
BPoD is also available in Catalan at www.bpod.cat with translations by the University of Valencia.