Motor pools organization depends on the combined function of N-cadherin and type II cadherins

Abstract

Type I and type II classical cadherins constitute a family of cell adhesion molecules expressed in complex combinatorial profiles in the nervous system, suggesting the hypothesis that a cadherin code implements specific adhesive recognition events that control the development of neural circuits. In the spinal cord, classical cadherins define at a molecular level the positional organization of motor neuron subtypes into discrete nuclear structures termed motor pools. However, the roles and contributions of different members of the family in defining motor neuron spatial organization are not clear yet. By combining mouse genetics with quantitative positional analysis, we found that motor neurons organization into pools depends on type II cadherins, nevertheless their function does not strictly reflect the predictions arising from binding specificities at a molecular level, but instead relies on N-cadherin, a type I cadherin whose elimination is required to reveal type II contributions.