ECROXXII Stockholm: “Profiling of OR genes expression in the human olfactory epithelium”

Olfactory recognition is mediated by a large repertoire of olfactory receptors (ORs). The human genome contains 851 OR loci. More than 50% of the loci are annotated as nonfunctional due to frame-disrupting mutations. Furthermore some missense haplotypic alleles can be nonfunctional due to a substitution of key amino acids governing protein folding or interactions with signal transduction components. Beyond their role in odor recognition, functional ORs are also required for a proper targeting of olfactory neuron axons to their corresponding glomeruli in the olfactory bulb (Feinstein et al, 2004). Therefore, profiling of OR genes expression in the olfactory epithelium provides an opportunity to select frequently expressed and potentially functional ORs for large deorphanization campaigns. An AB TaqMan® Low Density Array (TLDA) containing probes for 356 predicted OR loci was designed to investigate the expression of the chemosensory receptor genes expression in olfactory epithelium tissues from 8 individuals. Total RNA isolation, DNase treatment, RNA integrity evaluation and reverse transcription were performed for these 8 samples. Then 384 targeted genes (including reference genes for normalization) were analyzed using the same RT-qPCR platform. The expression of ~200 (56%) human OR genes was observed in the selected olfactory epithelia, among which 114 were robustly expressed in all tested individuals. No relation between OR gene expression and age or sex was observed. Most of the ORs (>80%) deorphanized at ChemCom or described in the literature were found in the expressed set. Download Pdf