Expression of two type II cadherins, Cdh12 and Cdh22 in the developing and adult mouse brain.

The expression of type II classic cadherins described so far displays a wide range of partially overlapping patterns during mammalian central nervous system development indicating their potential role during migratory and lamination processes as well as axon guidance. Expression of a few members of this family however, has not been characterized in detail. Here, we describe the spatio-temporal mRNA distribution pattern of two such neglected members of this family Cdh12 (also known as Br-cadherin) and Cdh22 (PB-cadherin) during mammalian CNS development using RT-PCR and in situ hybridization. In addition, we demonstrate the presence of Cdh12 and Cdh22 mRNA in specific and partially overlapping groups of both excitatory and inhibitory neurons in various areas of the adult mouse CNS including the cerebellum, neocortex, hippocampus and in different subcortical nuclei. Neocortical layer-specificity during development is further characterized using double in situ hybridization with the layer-specific markers cux2 and ctip2. The specific and partially overlapping expression patterns described here strongly suggest that these cadherins are likely to play a significant and quite possibly a partially redundant role during development and in the adult function of the mouse CNS.