Msx2 Prevents Stratified Squamous Epithelium Formation in the Enamel Organ

In the study, researchers investigated the role of the Msx2 gene in tooth enamel formation using Msx2 null mice. They found that while early differentiation of ameloblasts and stratum intermedium (SI) cells occurred normally, later stages showed abnormal proliferation of the outer enamel epithelium (OEE), which transformed into a keratinized stratified squamous epithelium. This transformation was marked by the expression of specific keratin genes and led to odontogenic cyst formation and disrupted enamel organ organization. Consequently, enamel failed to form in its normal location, and ectopic mineralization occurred. The study concluded that Msx2 played a crucial role in preventing the transformation of OEE into keratinized epithelium and in promoting the development of a properly differentiated enamel organ necessary for enamel formation.