Peripheral olfactory projections are differentially affected in mice deficient in a cyclic nucleotide-gated channel subunit

Axons of olfactory sensory neurons expressing a given odorant receptor conv erge to a few glomeruli in the olfactory bulb. We have generated mice with unresponsive olfactory sensory neurons by targeted mutagenesis of a cyclic nucleotide-gated channel subunit gene, OCNC1. When these anosmic mice were crossed with mice in which neurons expressing a given odorant receptor can be visualized by coexpression of an axonal marker, the pattern of convergen ce was affected for one but not another receptor. In a novel paradigm, term ed monoallelic deprivation, axons from channel positive or negative neurons that express the same odorant receptor segregate into distinct glomeruli w ithin the same bulb. Thus, the peripheral olfactory projections are in part influenced by mechanisms that depend on neuronal activity.