Coding Olfaction. Peter Mombaerts

The mammalian olfactory system is increasingly recognized as an attractive model system for studying the formation of neural circuits during development. An olfactory sensory neuron expresses just one the of ~1000 odorant receptor genes in the mouse genome. Axons of neurons a given odorant receptor gene converge onto a few of the ~1800 glomeruli in the olfactory bulb of the mouse. A mapping problem is thus posed: ~1000 populations of neurons, each expressing a distinct odorant receptor gene, must be sorted onto ~1800 glomeruli. A productive approach to study axonal coalescence has been targeted mutagenesis of odorant receptor genes, to express axonal markers in neurons expressing a given odorant receptor gene. These experiments have revealed that the odorant receptor is a critical determinant of axonal coalescence into glomeruli. My lecture will summarize the results of our research about the problems of odorant receptor gene choice and axonal wiring.