Inactivation of Fgfr2 gene in mouse secondary palate mesenchymal cells leads to cleft palate

Area of Science:

• Developmental Biology
• Molecular Biology
• Genetics

Background:

• Mammalian secondary palate development involves complex molecular mechanisms controlling growth, reorientation, and fusion.
• The specific signaling factors regulating palate initiation remain largely unknown.
• Fibroblast Growth Factor (FGF) receptor 2 (Fgfr2) is expressed early in palate development.

Purpose of the Study:

• To investigate the role of FGF receptor 2 (Fgfr2) signaling in the initiation of mammalian secondary palate development.
• To determine the function of Fgfr2 in palate cell specification and shelf formation.

Main Methods:

• Utilized mouse models with targeted inactivation of the Fgfr2 gene in mesenchymal cells using floxed Fgfr2 alleles and Osr2-Cre.
• Analyzed embryonic development at various stages (E11.5, E12.5, E13.5) to observe palate formation and identify defects.
• Examined Fgfr2 gene expression patterns in developing palatal tissues.

Main Results:

• Fgfr2 expression was detected in the palate outgrowth at E11.5, specifically in the maxillary process region responsible for palate cell specification and shelf initiation.
• Continued expression of Fgfr2 was observed in both epithelial and mesenchymal palate cells at E12.5 and E13.5.
• Inactivation of Fgfr2 in mesenchymal cells resulted in cleft palate phenotypes at multiple developmental stages, including defects in reorientation, horizontal growth, and fusion.
• A subset of mutant embryos exhibited a complete absence of palate shelf formation, indicating a critical role in initiation.

Conclusions:

• FGF receptor 2 mediated FGF signaling plays a vital role in the initiation of mammalian secondary palate development.
• Fgfr2 is essential for early palate shelf formation and subsequent developmental processes.
• Targeting Fgfr2 function provides insights into the molecular basis of craniofacial development and congenital palate defects.