The mesenchymal cadherin-11 is expressed in restricted sites during the ontogeny of the rat brain in modes suggesting novel functions.

Cadherin-11 (Cad-11), a cell cell adhesion molecule belonging to the "classical type II" cadherin family, is a marker of the loosely connected and migratory cellular elements of the mesenchyme. Interestingly, by using in situ hybridization, regional high expression of cad-11 was seen in the brain as well as the spinal cord. We made the following observations in rat embryos and neonates: (1) cad-11 first appears at the lips of the open neural tube; (2) shortly after neural tube closure, cad-11 delineates boundaries in the fore- and midbrain while a metameric signal is detected in the rhombencephalon; (3) cad-11 expression is found in specific neuroepithelia and ependyma; (4) in the fetal developing brain, cad-11 transcripts are present during the formation of precise cortical layers, in various brain nucleus or subsets of nuclei and in circumventricular organs; (5) intense cad-11 expression is located at the point of optic nerve exit and entry; (6) cad-11 signal accompanies, in a spatio-temporal manner, the dynamics of cell migration in the cortex from lateral ganglionic eminence through the cortico-striatal sulcus. These data are discussed, and hypotheses for additional and novel properties for cad-11 are suggested.