Boundary geometry controls a topological defect transition that determines lumen nucleation in embryonic development

Area of Science:

• Physics and Biology
• Material Science
• Developmental Biology

Background:

• Topological defects are crucial for anisotropic materials but their 3D configurations are not fully understood.
• The biological relevance of 3D polar defects, unlike 2D defects, remains unclear.

Purpose of the Study:

• To investigate the control of 3D topological defect configurations.
• To explore the biological role of 3D polar defects in embryonic development.

Main Methods:

• Investigated charge-preserving transitions between 3D defect configurations driven by boundary geometry.
• Studied 3D polar defects in mouse embryos and their role in lumen formation.
• Experimentally perturbed mouse embryo shape to validate findings.

Main Results:

• Discovered a transition between 3D defect configurations controlled by boundary geometry, independent of material properties.
• Identified 3D polar defects in mouse embryos as sites of fluid-filled lumen formation.
• Demonstrated that altering embryo shape creates new lumen initiation sites near predicted defect locations.

Conclusions:

• Boundary geometry is a key factor in controlling 3D polar defects.
• Embryos utilize shape-dependent lumen formation via polar defects for development.
• The principle of defect control by geometry may be broadly applicable to systems with orientational order.