Olfactory-like receptor cDNAs are present in human lingual cDNA libraries

Olfactory and pheromone receptors (ORs) constitute a large family of G-protein-coupled receptors involved in the detection and transduction of odorant signals. Using degenerated primers complementary to the highly conserved transmembrane domains II, III, VI, and VII within this protein family, Gaudin et al. have recently described the expression of several OR genes in foetal human tongue. Among the nine genes identified in human foetal tongue (HTPCR06, HGMP07I, JCG6, TPCR85, JCGI1, JCG2, JCG3, JCG5, and JCG9), only four (HTPCR06, HGMP07I, JCG3, and JCG5) were found to be expressed in adult tongue, suggesting that ORs might perform developmental functions in this organ. The objective of our work was to obtain additional information about the expression of olfactory-like genes in human tongue. In the present study, the synthesis and the screening of a cDNA library from epithelial cells of human adult tongue is reported. Two kinds of PCR analysis were performed. First, partial olfactory-like receptor cDNAs amplified with the degenerated primers used by Gaudin et al. were cloned and described. Second, a comparison of the expression profiles of the olfactory-like receptor genes previously identified before was carried out using specific primers. Among the genes studied we found that four genes (HTPCR06, JCG3, JCG5, and JCG6) are expressed in epithelial cells of the surface of the adult tongue. Additionally, we show that three olfactory-like receptor genes OR7A5/HTPCR2, OR6Q1, and OR7C1/TPCR86 are also expressed in these cells.