Segregated expression of neurestin in the developing olfactory bulb.

Neurestin is a putative transmembrane protein whose expression is developmentally regulated in neurons. Here we examined neurestin expression pattern in mitral/tufted cells in the developing rat olfactory bulb. In the main olfactory bulb, neurestin expression was segregated in the dorso-rostral area and in the ventro-caudal area, but not in between. In the accessory olfactory bulb, neurestin expression was found only in the far caudal area. This area did not completely correspond to a caudal half of the vomeronasal nerve and glomerular layers positive for a G-protein Go alpha. These spatio-temporal expression patterns suggest that neurestin functions as a target recognition molecule that specifies zonal projection patterns of olfactory and vomeronasal sensory neurons.