Localization of a Novel Renal Olfactory Receptor to Glomeruli

Abstract

Olfactory receptors (ORs) are chemosensory G Protein Coupled Receptors that comprise the largest mammalian gene family. ORs serve to identify odors in the nose, and also act as chemosensors in a variety of other tissues. We previously identified 8 renal ORs; here, we undertook a directed RT‐PCR screen for 10 ORs (primers were validated using genomic DNA, taking advantage of the fact that ORs lack introns). We identified 4 murine renal ORs consistently present in multiple kidney samples: Olfactory Receptors 31, 746, 1418 and 1426 (Olfr31, Olfr746, Olfr1418, and Olfr1426; sequenced to confirm). Among these, only Olfr31 has a clear human ortholog. No validated antibodies are available for these ORs. Therefore, to localize these ORs we developed a laser capture microdissection protocol for specific kidney segments, followed by RNA isolation and RT‐PCR. Olfr31 localized to glomeruli by RT‐PCR (glomeruli RNA sample purity was validated by RT‐PCR for nephrin, and absence of RT‐PCR band for NCC and megalin). We have now cloned the full‐length sequence of Olfr31, and hope to identify its ligand(s) using a reporter gene assay (Olfr31 has no known ligand). In sum, we have identified four murine renal ORs and have localized one, Olfr31, to renal glomeruli. Further studies will focus on localizing Olfr746, Olfr1418, and Olfr1426; identifying Olfr31 ligands, and examining the potential roles of these receptors in vivo. Funding: NIDDK