FIGURE 6.

Molecular mechanisms of secondary palate fusion. (a) Schematic diagram illustrating the morphological events in secondary palatal fusion. (b) TGFβ signalling promotes MES degeneration and extracellular matrix remodelling by regulating cascades involving Irf6 and Mmp13, respectively. The transcription factors Irf6 and Tp63 function in a regulatory feedback loop to control medial edge epithelial cell fate. Rho‐kinase (ROCK) and myosin light‐chain kinase (MLCK) converge to activate non‐muscle myosin IIA (NMIIA), driving actomyosin contractility. Together this pathway regulates epithelial convergence, displacement, extrusion and migration to ensure midline epithelial seam dissolution and mesenchymal continuity. Adapted from Kim et al., 2015. MEE, medial edge epithelia; MES, midline epithelial seam