Site of Biosynthesis of the Mouse Brain Olfactory Bulb Protein

The mouse brain olfactory bulb protein has now been shown to occur in two locations in addition to the olfactory bulb. These two sites, the olfactory epithelium and Jacobson's vomeronasal organ, contain the perikarya of the olfactory bipolar chemoreceptor cells which synapse in the olfactory bulb. The protein is absent from a variety of other sites, both central and peripheral. Utilizing the techniques of 3H-amino acid incorporation, immunoprecipitation, and sodium dodecyl sulfate-acrylamide gel electrophoresis, we have been able to demonstrate that this protein is synthesized in both the olfactory epithelium and Jacobson's vomeronasal organ, but not in the olfactory bulb. These results strongly suggest that this protein is synthe-sized by the olfactory chemoreceptor bipolar neurons, and that it is then transported by axoplasmic flow to the synaptic glomeruli in the olfactory bulb where it was first discovered. This protein is an example of selective genetic expression by a specific neuron.