Temporal dynamics of BMP/Nodal ratio drive tissue-specific gastrulation morphogenesis

Area of Science:

• Developmental biology
• Cell biology
• Genetics

Background:

• Vertebrate anteroposterior (AP) axis elongation relies on convergence and extension (C&E) movements in mesoderm and neuroectoderm.
• The molecular regulation of C&E across these distinct tissues is not fully understood.

Approach:

• Utilized a zebrafish explant model to investigate AP axis extension ex vivo.
• Manipulated Bone Morphogenetic Protein (BMP) and Nodal signaling pathways temporally.
• Observed the effects of varying BMP/Nodal ratios on neuroectoderm and mesoderm C&E.

Key Points:

• Neuroectoderm and mesoderm C&E can be uncoupled, demonstrating tissue-specific morphogenesis.
• A critical developmental window exists where BMP/Nodal ratios dictate tissue-specific C&E.
• High BMP/Nodal ratios promote neuroectoderm-driven C&E, while low ratios favor mesoderm-driven C&E.
• Increased BMP activity enhances ectodermal C&E in intact zebrafish gastrulae.

Conclusions:

• Temporal dynamics of BMP and Nodal signaling differentially regulate C&E in zebrafish.
• Distinct morphogenetic programs are activated by specific morphogen signaling ratios within tissues.
• Findings highlight the tissue-specific molecular control of gastrulation movements during vertebrate development.