Dresden 2020 – scientific programme
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BP: Fachverband Biologische Physik
BP 40: Systems Biology, Evolution and Neural Networks II
BP 40.5: Talk
Friday, March 20, 2020, 10:30–10:45, ZEU 250
Long-ranged signalling gradients generated by short-ranged molecular interactions — •Johanna Dickmann1,2, Jochen Rink2, and Frank Jülicher1 — 1Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — 2Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
Embryonic development, regeneration, and tissue renewal require tissue organisation as can be provided by signalling molecules forming concentration profiles in space, i.e. signalling gradients. Planarian flatworms are a great model for tissue organisation as they constantly turn over their entire body and are able to regenerate from arbitrary amputation fragments. At a body length of up to 2 cm, they are orders of magnitudes larger than tissue organised during embryonic development in other species, yet, they employ signalling gradients for tissue organisation. In this project we investigate how such long-ranged signalling gradients can be formed. We chose the Wnt signalling gradient organising the main body axis of the worm as a model system. Building a discrete 1D model we account for signalling molecule levels in the extracellular space and signalling levels inside the cells. We consider diffusion and degradation of signalling molecules as suggested to explain signalling gradient formation during development. Motivated by observations in the worm, we add positive feedback. Thus, all cells become sources of signalling molecules. The directionality of the profile is organised by a signal-independent input from one side. The suggested mechanism can explain the formation of signalling gradients with a longer length scale compared to the diffusion/degradation mechanism.