Expression of cadherin-11 delineates boundaries, neuromeres, and nuclei in the developing mouse brain.
Cadherin-11 (cad11 or OB-cadherin) was previously identified as a mesenchymal cell-cell adhesion molecule. Here we studied the expression of cad11 transcripts in developing brains derived from E11.5 to E16.5 mouse embryos. In the brains at these stages, cad11 was expressed in various patterns, which could be grouped into three categories. First, cad11 expression occurred along boundaries between certain brain subdivisions, including those between the ventral and dorsal thalamus and between the mesencephalon and metencephalon. At these boundaries, cad11-positive cells were localized in a narrow, columnar compartment of the neuroepithelium. Second, cad11 expression delineated particular neuromeric compartments at the ventricular zone of the neuroepithelium. A typical example of this pattern was observed in the hypothalamus. Third, cad11 was expressed in differentiating or differentiated brain nuclei. The former included the thalamus, epithalamus, and pretectum; the latter included the mammillary, red, trigeminal motor, facial motor, prepositus hypoglossal, and inferior olive nuclei, as well as the substantia nigra. Furthermore, developing nuclei and the superficial zone of the cerebellum expressed cad11, and the cortical plate of the developing cerebrum also did so. We compared the expression pattern of cad11 with that of R-cadherin in the diencephalon and found that each cadherin delineated a unique set of diencephalic subdivisions. These findings suggest that cad11-mediated specific cell-cell adhesion plays roles in segmentation or compartmentalization of the developing brain in various ways. We also discussed the possibility that cad11 might be involved in neuronal connections between specific nuclei.