Receptor diversity and spatial patterning in the mammalian olfactory system

In order to gain insight into the mechanisms underlying olfactory perception in mammals, we have performed experiments to identify and characterize the basic receptive elements of the olfactory system, the odorant receptors. We have identified a novel multigene family that encodes odorant receptors on olfactory sensory neurons in the nasal cavity. The tremendous size and diversity of this family indicate that perceptual acuity in the olfactory system relies heavily on the differential binding properties of hundreds of different receptor types. In order to determine how the information supplied by such a large collection of diverse receptors might be organized, we have examined the patterns of expression of different odorant receptor genes in the olfactory epithelium. We have observed distinct topographical patterns of odorant receptor RNAs that indicate that the olfactory epithelium is divided into a series of expression zones. These zones are likely to provide for a broad organization of sensory information in the nasal cavity which is maintained in the axonal projection to the olfactory bulb.