| Mammals possess the remarkable ability to detect and discriminate many thousands of chemical compounds or odorants. The molecular receptors underlying the sense of smell comprise a large family of ∼1000 olfactory receptors (ORs), and two families of vomeronasal receptors (∼200 V1Rs and ∼200 V2Rs), all belonging to the seven transmembrane G-protein coupled receptor (GPCR) superfamily. We have performed comprehensive data mining in the mouse genome and identified ∼1000 OR genes and ∼160 V1R genes, plus ∼350 OR pseudogenes and ∼150 V1R pseudogenes. These receptor genes tend to form multiple tight clusters of related subfamilies and these clusters are widely dispersed in the genome. Phylogenetic analysis has led to family classification, as well as systematic nomenclature for ORs and V1Rs. Furthermore, we applied an automatic and unsupervised system to the OR sequences and generated 86 motifs. These conserved motifs are likely to have important biological functions and could provide essential information about the structure-function relation of OR proteins. Finally, we have designed a custom made high-density oligonucleotide array for mouse OR and V1R genes. With this array we were able to specifically detect the expression of a large number of the receptor genes and monitor gene expression across various tissues, developmental stages, and genetic backgrounds. Our observation of the correlation between genomic location and spatial expression of OR genes suggested a potential mechanism for gene regulation. |
