Generating active T1 transitions through mechanochemical feedback.

Area of Science:

• Developmental Biology
• Cellular Mechanics
• Biophysics

Background:

• Embryonic convergence-extension relies on chemical and mechanical signals.
• Cell neighbour exchange via T1 transitions is a key process.
• Understanding the regulation of these cellular rearrangements is crucial.

Purpose of the Study:

• To model the positive feedback mechanism between myosin motors and mechanical tension in cell junctions.
• To investigate how active T1 events contribute to tissue elongation.
• To determine the role of mechanical stresses in driving convergence-extension.

Main Methods:

• Development and analysis of a computational model incorporating positive feedback.
• Simulation of tissue patches with active and passive cells.
• Analysis of stress distribution and T1 transition dynamics under varying mechanical conditions.

Main Results:

• The model predicts active T1 events that elongate tissue perpendicular to stress.
• An optimal range of mechanical stresses was identified for triggering active T1 events.
• Directed stresses induce tension chains and convergence-extension in realistic cell configurations.

Conclusions:

• Active intercalations can generate self-sustaining stress, activating neighboring T1 events.
• Tissue reorganisation is tension-dependent, aligning with experimental observations in gastrulation.
• The proposed model provides a framework for understanding mechanical control of tissue morphogenesis.