PAPC mediates self/non-self-distinction during Snail1-dependent tissue separation

Area of Science:

• Developmental Biology
• Cell Biology
• Molecular Biology

Background:

• Cleft-like boundaries are crucial for tissue separation during embryonic development.
• Understanding the molecular mechanisms of these boundaries is essential for developmental processes.

Purpose of the Study:

• To investigate the molecular players and mechanisms underlying cleft-like boundary formation.
• To elucidate the roles of Snail1 and paraxial protocadherin (PAPC) in ectoderm-mesoderm boundary separation.

Main Methods:

• Studied cleft-like ectoderm-mesoderm boundaries in Xenopus laevis and zebrafish gastrulae.
• Identified the transcription factor Snail1 and its dependence on noncanonical Wnt signaling.
• Investigated the novel functions of paraxial protocadherin (PAPC) in tissue separation.

Main Results:

• Snail1 is essential for tissue separation at the ectoderm-mesoderm boundary.
• PAPC attenuates planar cell polarity signaling, reducing cell adhesion and promoting cleft formation.
• PAPC mediates unique adhesive contacts at the single-cell level, characterized by adherens junction-like contacts and intercellular gaps.

Conclusions:

• Snail1 and PAPC are critical for establishing cleft-like boundaries.
• PAPC exhibits dual functions in facilitating tissue separation: reducing adhesion and mediating specific cell contacts.
• These functions establish a self/non-self-recognition mechanism for boundary site determination.