Adhesion molecules during somitogenesis in the avian embryo

Area of Science:

• Developmental Biology
• Cell Adhesion
• Morphogenesis

Background:

• Somites are fundamental units of metameric patterning in avian embryos.
• Somite formation involves mesenchymal-to-epithelial transition and subsequent differentiation.
• Understanding cell adhesion molecules is key to dissecting tissue remodeling processes.

Purpose of the Study:

• To investigate the roles of cell adhesion molecules (CAMs) in avian somitogenesis and tissue remodeling.
• To elucidate the specific contributions of N-cadherin, N-CAM, fibronectin, and laminin.
• To examine the spatio-temporal expression and functional significance of these molecules in vivo and in vitro.

Main Methods:

• In vitro cell aggregation assays using segmental plate and somitic cells.
• In vivo analysis of spatio-temporal expression of CAMs during somitogenesis.
• In vitro somite culture and tissue dissociation assays with antibodies and calcium depletion.

Main Results:

• N-cadherin mediates calcium-dependent cell aggregation in segmental plate and somitic cells.
• N-cadherin expression correlates with somite formation and disruption; its absence or antibody inhibition causes significant tissue dissociation.
• N-CAM plays a minor role in somite remodeling, while fibronectin and laminin are involved in secondary stabilization and positioning.

Conclusions:

• N-cadherin is a primary regulator of tissue remodeling during avian somitogenesis.
• N-CAM contributes to a lesser extent in the remodeling process.
• Fibronectin and laminin are not primary regulators of cell cohesion but may influence cell positioning and epithelial stabilization.