The odor specificities of a subset of olfactory receptor neurons are governed by Acj6, a POU-domain transcription factor

Little is known about how the odor specificities of olfactory neurons are g enerated, a process essential to olfactory coding. We have found that neuro nal identity relies on the abnormal chemosensory jump 6 (acj6) gene, origin ally identified by a defect in olfactory behavior. Physiological analysis o f individual olfactory neurons shows that in acj6 mutants, a subset of neur ons acquires a different odorant response profile. Certain other neurons do not respond to any tested odors in acj6. Molecular analysis of acj6 shows that it encodes a POU-domain transcription factor expressed in olfactory ne urons. Our data suggest that the odor response spectrum of an olfactory neu ron, and perhaps the choice of receptor genes, is determined through a proc ess requiring the action of Acj6.