Nematic structures contribute to robust zygotic polarization in C. elegans.

Nematic cortical structures in C. elegans zygotes ensure robust polarization by aligning actin bundles and tension, especially during lateral symmetry breaking.

• Why it matters: Understanding how mechanical cortical architecture influences cell polarization fills a critical gap in cell biology, complementing known biochemical mechanisms and revealing how physical forces contribute to asymmetric division.
• What they did: A three-dimensional mechanical model was developed, representing actin bundles and myosin foci as a network of stiff contractile filaments, and cortical flow was measured with high resolution to inform the model.
• The result: The model demonstrated that nematic cortical structures create tension anisotropy and mechanical feedback, which stabilize polarization and facilitate axis convergence, especially during lateral symmetry breaking.