EVIDENCE FOR DIFFERENT CHEMOSENSORY SIGNAL-TRANSDUCTION PATHWAYS IN OLFACTORY AND VOMERONASAL NEURONS

Both the olfactory and vomeronasal epithelia mediate chemosensory rece ption. Here we report that several molecules that are highly expressed in the olfactory epithelium and therefore are likely to be important mediators of olfactory signal transduction (Golf alpha, adenylyl cycla se III and the olfactory cyclic nucleotide gated ion channel) are nor present in the vomeronasal epithelium. Therefore it appears that disti nct molecules mediate chemosensory signal transduction in the olfactor y and vomeronasal epithelia. The genes for Golf alpha, adenylyl cyclas e III, the olfactory cyclic nucleotide gated ion channel, G gamma 8 an d olfactory marker protein which are all expressed in the olfactory ep ithelium have consensus Olf-1 binding sites. The transcription factor Olf-1 was found to be highly expressed in the olfactory epithelium and was detected at a similar level in the vomeronasal epithelium. The ex pression pattern of Olf-1 did not correlate with that of molecules inv olved in olfactory signaling but was more similar to the expression pa ttern of G gamma 8 and olfactory marker protein which are found both i n olfactory and vomeronasal neurons. Therefore, expression of Olf-1 in the olfactory epithelium and the presence of Olf-1 binding sites in a number of different genes found to be expressed in the olfactory epit helium are not sufficient to explain the observed gene expression patt erns. (C) 1996 Academic Press, Inc.