A RECEPTOR GUANYLYL CYCLASE EXPRESSED SPECIFICALLY IN OLFACTORY SENSORY NEURONS

We have cloned an additional member (GC-D) of the membrane receptor gu anylyl cyclase [GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2] famil y that is specifically expressed in a subpopulation of olfactory senso ry neurons. The extracellular, putative ligand-binding domain of the o lfactory cyclase is similar in primary structure to two guanylyl cycla ses expressed in the retina but diverges considerably from other known guanylyl cyclases. The expression of GC-D RNA is restricted to a smal l, randomly dispersed population of neurons that is within a single to pographic zone in the olfactory neuroepithelium and resembles the patt ern of the more diverse seven-transmembrane-domain odorant receptors. These observations suggest that GC-D may function directly in odor rec ognition or in modulating the sensitivity of a subpopulation of sensor y neurons to specific odors.