Cell contacts and pericellular matrix in the Xenopus gastrula chordamesoderm

Area of Science:

• Developmental Biology
• Cell Biology
• Biophysics

Background:

• Convergent extension is a key gastrulation movement in Xenopus.
• Cell-cell contacts are crucial for tissue morphogenesis.
• The role of pericellular matrix in chordamesoderm adhesion is not fully understood.

Purpose of the Study:

• To investigate the general features of cell-cell contacts in the Xenopus chordamesoderm.
• To understand the contribution of adhesion factors and pericellular matrix to cell adhesion.
• To model chordamesoderm cell adhesion based on experimental data.

Main Methods:

• Depletion of adhesion factors: C-cadherin, Syndecan-4, fibronectin, and hyaluronic acid.
• Analysis of cell contact width spectra and contact angles.
• La3+ staining to visualize the pericellular matrix.
• Quantitative description of pericellular matrix deployment.

Main Results:

• Cell-cell adhesion in chordamesoderm is mediated by pericellular matrix, with unique La3+ stained structures (10-20 nm wide).
• Depletion of adhesion factors reduced cell contact abundance but maintained relative adhesiveness.
• Adhesiveness increased proportionally with contact width, suggesting interdigitating matrix units.
• Reduced contact abundance correlated with matrix accumulation in gaps and loss of certain contact types.

Conclusions:

• Pericellular matrix plays a significant role in Xenopus chordamesoderm cell adhesion.
• Adhesion factor depletion affects matrix distribution and cell contact dynamics.
• A model involving interdigitating pericellular matrix units explains chordamesoderm adhesion.