Members of the Dbx family are implicated in regionalization of the CNS. Dbx2 is restricted to the ventricular region of the embryonic CNS as well as some of the mesenchymal cells, such as limb buds and tooth germs. BMP regulation of the expression boundaries of the homeobox proteins Dbx2, Pax6 and Msx1 generates precursor populations with distinct developmental potentials.