Dynamic Lunatic fringe expression is correlated with boundaries formation in developing mouse teeth

The formation of boundaries is a fundamental organizing principle during de velopment. The Notch signalling pathway regulates this developmental patter ning mechanism in many tissues. Recent data suggest that Notch receptors ar e involved in boundary determination during odontogenesis. It remains, howe ver, uncertain if other components of the Notch pathway are also important for compartmental lineage restrictions in teeth. Here we report on the expr ession of the Lunatic fringe gene, which encodes a secreted signalling mole cule regulating the Notch pathway, during the development of mouse teeth. L unatic fringe is expressed in both epithelial and mesenchymal components of the developing molar. The expression pattern of Lunatic fringe in the epit helium is complementary to that of the Notch receptors. Lunatic fringe is a symmetrically expressed in the incisor epithelium during its antero-posteri or rotation. This expression pattern defines the lingual comportment of the incisor epithelium whereas the labial comportment is defined by Notch2 exp ression. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.