Regensburg 2022 – scientific programme
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BP: Fachverband Biologische Physik
BP 6: Statistical Physics of Biological Systems 1 (joint session BP/DY)
BP 6.2: Talk
Monday, September 5, 2022, 15:15–15:30, H16
Boundary-driven epithelial ordering: from the mouse embryo to topological defects — •Pamela Guruciaga1, Takafumi Ichikawa2, Takashi Hiiragi3, and Anna Erzberger1 — 1European Molecular Biology Laboratory, Heidelberg, Germany — 2Kyoto University, Kyoto, Japan — 3Hubrecht Institute, Utrecht, The Netherlands
In physical problems boundaries are typically considered to be simple, static and externally fixed. Biological systems however not only interact with their surroundings, but also alter them in ways that feed back on their own dynamics. We address this complex interaction in the context of epithelial development. Motivated by observations of an interplay between apico-basal polarity and boundary geometry in mouse epiblast morphogenesis, we develop a theory for epithelial ordering based on the Landau-de Gennes approach to surface-induced order in liquid crystals. We introduce a vector order parameter to represent the polarity, and model its interaction with the boundaries by a weak anchoring energy. We calculate the alignment fields arising from different boundary curvatures, and compare our predictions with imaging data of the morphogenetic process. Our work highlights the role of extraembryonic tissue in embryogenesis, while identifying interesting physical phenomena, such as boundary-dependent transitions in the structure of topological defects.