Neural crest ontogeny during secondary neurulation: a gene expression pattern study in the chick embryo

Area of Science:

• Developmental biology
• Embryology
• Molecular biology

Background:

• Secondary neurulation in chick embryos generates neural crest cells (NCC).
• Molecular mechanisms of secondary NCC development were previously uncharacterized.
• NCC contribute to diverse cell lineages in the developing embryo.

Purpose of the Study:

• To investigate the molecular players involved in secondary NCC generation and ontogeny.
• To compare molecular events in secondary NCC development with primary neurulation.

Main Methods:

• Detailed expression study of molecular factors in chick embryos (HH18-20).
• Analysis focused on the lumbo-sacral region, specifically somites 30-43.
• Investigated transcription factors, cell adhesion, and extracellular matrix interactions.

Main Results:

• Key transcription factors (Pax3, Pax7, Snail2, FoxD3, Sox9) are expressed during secondary NCC specification.
• NCC emigration involves cell shape/adhesion changes and matrix interactions.
• Bmp4 and Wnt1 expression precedes NCC migration and coincides with somite maturation.

Conclusions:

• Secondary NCC specification utilizes conserved molecular pathways seen in primary neurulation.
• Mechanisms for neural crest generation are conserved across different neurulation types in chick embryos.
• This study provides the first molecular insights into secondary NCC ontogeny.