TWIST1 Modulates Cilia Length, Endocytic Vesicle Dynamics, and Cell-Cell Junctions during Neural Tube Morphogenesis

Area of Science:

• Cell Biology
• Developmental Biology
• Genetics

Background:

• Endocytosis is crucial for embryonic development, regulating plasma membrane remodeling and ciliogenesis.
• TWIST1 (Twist-related protein 1) is known to affect neural tube closure and neural crest cell fate.
• The specific role of TWIST1 in neural tube morphogenesis was previously unknown.

Purpose of the Study:

• To investigate the function of TWIST1 in neuroectodermal morphology.
• To understand the molecular mechanisms behind neuroectodermal abnormalities in TWIST1 mutants.
• To examine TWIST1's role in cilia formation, adherens junction integrity, and endocytic vesicle dynamics.

Main Methods:

• Immunofluorescence analysis to observe TWIST1 localization with cellular markers.
• Analysis of ciliary length and number in TWIST1 knockout embryos.
• Quantitative PCR and Western blot to assess gene and protein expression levels.
• Examination of endocytic vesicle accumulation and gene expression profiles.

Main Results:

• Cytosolic TWIST1 localizes with β-catenin and endocytic regulators (LRP2, RAB11B) at the apical surface of cranial neuroectoderm.
• TWIST1 knockout leads to reduced ciliary length and number.
• Upregulation of RAB11B and β-catenin was observed in TWIST1 mutants at both mRNA and protein levels.
• Increased apical endocytic vesicle accumulation and altered expression of endocytic genes were noted, affecting cell-cell junctions.

Conclusions:

• TWIST1 is established as a regulator of neuroectodermal morphology.
• TWIST1 modulates ciliogenesis, endocytic vesicle dynamics, and cell-cell junction integrity.
• These findings provide insights into the molecular basis of neural tube development and associated defects.