Somite Division and New Boundary Formation by Mechanical Strain

Area of Science:

• Developmental Biology
• Mechanobiology
• Embryogenesis

Background:

• Somitogenesis, the segmentation of vertebrate embryos, involves oscillating genes and cell differentiation.
• Mechanical cues like cell-matrix adhesion and embryonic tension are suggested to play a role.

Purpose of the Study:

• To investigate the role of mechanical cues in somitogenesis by applying axial strain to chick embryos.
• To determine if mechanical strain influences somite formation and organization.

Main Methods:

• Live chick embryos were subjected to surplus axial strain.
• Somite formation rate, cellular reorganization, and cell morphology were analyzed.
• A Cellular Potts model was used to simulate somite division.

Main Results:

• Embryos developed normally and somite formation rate was unaffected by substantial deformations.
• Elongated somites underwent cellular reorganization, dividing into daughter somites with new boundary formation and fibronectin deposition.
• Cells from the somitocoel exhibited mesenchymal-epithelial transition, supporting the observed somite division.

Conclusions:

• Somitogenesis is robust to mechanical strain, but strain can be morphologically instructive.
• Mechanical forces can induce new boundary formation and division within existing somites.
• Cellular Potts model supports the mechanism of somite division driven by mechanical cues.