Neurulation and the cortical tractor model for epithelial folding.

Area of Science:

• Developmental Biology
• Cell Biology
• Biophysics

Background:

• Epithelial morphogenesis involves complex cell movements and tissue shaping.
• The maintenance of the apical seal is crucial for epithelial integrity during development.
• Existing models do not fully capture the dynamic nature of epithelial cell motility and tissue dynamics.

Purpose of the Study:

• To propose a novel model, the 'cortical tractor model,' for epithelial morphogenesis.
• To explain how epithelial cells maintain motility while remaining attached apically.
• To demonstrate the model's ability to reproduce various epithelial morphogenetic movements.

Main Methods:

• Development of a new biophysical model for epithelial cell behavior.
• Mechanical analyses of cellular forces and movements.
• Computer simulations to test the model's predictions.

Main Results:

• The cortical tractor model describes a continuous flow of cortical cytoplasm, inserting and resorbing membrane/adhesive structures.
• This model explains the dynamic nature of the apical seal.
• Simulations show the model reproduces columnarization, invagination, and rolling, and drives cell rearrangements.

Conclusions:

• The cortical tractor model provides a unified mechanism for diverse epithelial morphogenetic movements.
• It offers a new perspective on how epithelial integrity is maintained during dynamic shape changes.
• The model effectively explains complex processes like amphibian neurulation.