Berlin 2024 – scientific programme
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BP: Fachverband Biologische Physik
BP 34: Statistical Physics of Biological Systems III (joint session BP/DY)
BP 34.7: Talk
Friday, March 22, 2024, 11:30–11:45, H 2032
Boundary geometry drives three-dimensional defect transitions in a polar fluid — •Pamela Guruciaga1, Takafumi Ichikawa2, Takashi Hiiragi2,3, and Anna Erzberger1,4 — 1European Molecular Biology Laboratory, Heidelberg, Germany — 2Kyoto University, Kyoto, Japan — 3Hubrecht Institute, Utrecht, The Netherlands — 4Heidelberg University, Heidelberg, Germany
Motivated by observations of an interplay between apico-basal polarity and boundary geometry in mouse embryo morphogenesis, we develop a minimal model to address the role of boundaries---with emphasis on their geometry---in the surface-induced ordering of a 3D polar fluid. We find that, although material parameters are responsible for the creation of defects in the order parameter field, their location and structure are determined by the system geometry. We test our results in the experimental context of the mouse epiblast, where cells gradually align along their apico-basal axis and eventually form a fluid filled cavity (lumen) at their apical sides. Since field defects represent regions where the apical sides of the cells meet, changes in defect position can be relevant to lumen formation in the biological system. We compare our predictions with imaging data of the morphogenetic process for wildtype and genetically perturbed mice, finding a remarkable quantitative agreement without any fitting parameters. Our work provides insights into luminogenesis and embryonic viability, while paving the way for defect control by geometry manipulation in more general settings.
Keywords: topological defects; surface-induced alignment; geometry; morphogenesis; luminogenesis