Dynamic expression of lunatic fringe during feather morphogenesis: a switch from medial-lateral to anterior-posterior asymmetry.

Expression of Lunatic fringe mRNA was studied during feather morphogenesis and showed three stages of dynamic expression pattern. (1) Lunatic fringe was first expressed in the epithelium as a ring bordering the feather primordium when it was initially induced. (2) Shortly after, it showed a polarized pattern, first toward the lateral side of the feather primordium and then made a 90 degrees C switch toward the posterior side of the short bud. It then becomes weakly expressed in the long bud stage. (3) Finally, it is expressed in the marginal plate epithelia of feather filaments. In contrast, Radical fringe is weakly expressed in the feather bud, but is also present in the marginal plate epithelia of feather filaments.