Viennese biologist identifies signaling pathway that directs sea anemone cells during reorganization

Background: Sea anemones as a model organism

Technau works at the Department of Neuroscience and Developmental Biology at the University of Vienna. The findings gain significance because they allow conclusions to be drawn about evolutionarily very old control mechanisms that also play a role in human embryonic development.

Sea anemones possess a comparatively simple body structure but are suitable as a model organism due to their position in the animal tree of life. If the tissue of an anemone is mechanically broken down into individual cells and then reassembled, the cells reform structures that correspond to the original body plan. Which mechanism drives this self-organization was previously only partially understood.

The team was able to show that the Notch signaling pathway becomes active in "Nematostella vectensis" as soon as cells encounter one another. "Der Notch-Signalweg sorgt dafür, dass sich die Zellen von ‚Nematostella vectensis'-Seeanemonen korrekt sortieren und unterschiedliche Gewebetypen voneinander abgrenzen", explained Technau in a press release from the University of Vienna.

Function of the Notch signaling pathway

If the signaling pathway is experimentally blocked, this order breaks down. "Dann funktioniert diese Selbstorganisation nicht mehr", says Technau. If the signal is missing, cell types that normally form clearly separated layers become mixed. The experiment thus provides direct evidence for the function of the signaling pathway in pattern formation.

Beyond its fundamental significance, the authors point out parallels to vertebrate development. The Notch signaling pathway has long been known from mammalian embryology; the new work shows that the same mechanism already performs a comparable task in cnidarians, a very evolutionarily ancient animal phylum.

Methodologically, the researchers combined live-cell microscopic observation with targeted genetic interventions. By switching off individual Notch components, they were able to demonstrate that the correct spatial sorting of cells is coupled to an active Notch signal.

Significance for developmental biology

The University of Vienna sees the finding as further evidence that simple model organisms can reveal fundamental principles of developmental biology. The results are intended to serve as a starting point for further work on the evolution of tissue organization and pattern formation.

For the contextualization of the study, it is essential that "Nature Communications" is considered a peer-reviewed journal and that the results had to withstand a peer-reviewed context. The work thus joins a series of publications that specifically use marine model organisms to address questions in developmental biology.

Overall, the data from Vienna open up a new detailed understanding of how structured tissues arise from seemingly uniform cells – and what role a single signaling pathway has played in this for hundreds of millions of years.

The study appears at a time when international research networks are increasingly searching for conserved, that is, evolutionarily preserved, control mechanisms in order to better understand disease patterns in which tissue demarcation is disrupted. The Viennese findings provide a further building block in this regard.