The TET-Sall4-BMP regulatory axis controls craniofacial cartilage development

Area of Science:

• Developmental Biology
• Genetics
• Molecular Biology

Background:

• Craniofacial microsomia (CFM) is a congenital defect impacting embryonic pharyngeal arch development.
• The precise molecular mechanisms underlying CFM pathogenesis remain largely unidentified.

Purpose of the Study:

• To investigate the molecular basis of craniofacial microsomia pathogenesis using a zebrafish model.
• To elucidate the roles of Tet2/3 and Sall4 in pharyngeal cartilage development.

Main Methods:

• Utilized zebrafish embryos for experimental studies.
• Employed single-cell RNA sequencing to analyze gene expression changes.
• Conducted biochemical and genetic analyses to determine protein interactions and regulatory functions.

Main Results:

• Tet2 and Tet3 were found to be essential for pharyngeal cartilage development in zebrafish.
• Loss of Tet2/3 function impaired chondrocyte differentiation due to insufficient BMP signaling.
• Sall4 was identified as a sequence-specific 5mC/5hmC-binding protein that activates bmp4 expression.
• Sall4 facilitates Tet2/3-mediated 5mC oxidation on the bmp4 promoter, promoting BMP signaling.

Conclusions:

• The TET-BMP-Sall4 regulatory axis is critical for proper pharyngeal cartilage development.
• Dysregulation of this axis may contribute to craniofacial microsomia pathogenesis.
• Findings offer insights into craniofacial development and CFM etiology.