Trpc2 is expressed in two olfactory subsystems, the main and the vomeronasal system of larval Xenopus laevis

Complete segregation of the main olfactory epithelium (MOE) and the vomeronasal epithelium is first observed in amphibians. In contrast, teleost fishes possess a single olfactory surface, in which genetic components of the main and vomeronasal olfactory systems are intermingled. The transient receptor potential channel TRPC2, a marker of vomeronasal neurons, is present in the single fish sensory surface, but is already restricted to the vomeronasal epithelium in a terrestrial amphibian, the red-legged salamander (Plethodon shermani). Here we examined the localization of TRPC2 in an aquatic amphibian and cloned the Xenopus laevis trpc2 gene. We show that it is expressed in both the MOE and the vomeronasal epithelium. This is the first description of a broad trpc2 expression in the MOE of a tetrapod. The expression pattern of trpc2 in the MOE is virtually undistinguishable from that of MOE-specific v2rs, indicating that they are co-expressed in the same neuronal subpopulation.