Sorting at embryonic boundaries requires high heterotypic interfacial tension.

Area of Science:

• Developmental Biology
• Cell Biology
• Biophysics

Background:

• Establishing sharp boundaries is crucial for embryonic tissue segregation.
• Mechanisms of cell sorting, whether global tissue properties or local cell-cell cues, remain debated.

Purpose of the Study:

• To investigate the roles of global adhesion, contractility, and local signaling in embryonic tissue separation.
• To elucidate the primary drivers of cell sorting during Xenopus ectoderm-mesoderm segregation.

Main Methods:

• Utilized Xenopus embryos to experimentally assess ectoderm-mesoderm separation.
• Employed computer simulations to model and generalize experimental findings on tissue segregation.

Main Results:

• Ephrin-Eph-based repulsion was found to be highly effective in inducing and maintaining tissue separation.
• Differences in global adhesion or contractility had minimal impact on cell sorting.
• High heterotypic interfacial tension was identified as the key factor for tissue segregation.

Conclusions:

• Local repulsion and interfacial tension are the primary drivers of embryonic tissue segregation.
• Differential adhesion/tension models represent suboptimal cases of heterotypic interfacial tension.
• A unifying model emphasizes interfacial tension for understanding cell sorting mechanisms.