Embryological methods in ascidians: the Villefranche-sur-Mer protocols

Area of Science:

• Developmental Biology
• Marine Invertebrate Zoology
• Evolutionary Biology

Background:

• Ascidians (urochordates) are the closest relatives to vertebrates.
• They possess a non-duplicated genome and synchronous embryonic development.
• Their stereotyped cleavage patterns lead to rapid cell fate restriction.

Purpose of the Study:

• To provide essential protocols for ascidian research.
• To detail methods for studying cell lineage specification and differentiation.
• To explore ascidian contributions to understanding fertilization, cell cycle, and regeneration.

Main Methods:

• Basic culture of embryos (Ciona intestinalis, Phallusia mammillata).
• Micro-injection, in vivo labelling, and micro-manipulations.
• Isolation and re-association of blastomeres and cortical fragments.

Main Results:

• Methods allow analysis of calcium signals, cytoplasmic/cortical dynamics, and cell cycles.
• Techniques facilitate study of gene roles and cellular interactions in development.
• Experimental manipulations elucidate egg cortex and blastomere functions.

Conclusions:

• Ascidians offer complementary advantages for molecular, functional, and imaging studies.
• Protocols support detailed investigation of early developmental events.
• Ascidian models are crucial for understanding fundamental biological processes shared with vertebrates.