1 1 Symposium Chemosensory Receptors Satellite DEVELOPMENT ...

333 Poster Chemosensory Molecular Genetics andVNO/PheromoneA POSSIBLE GENETIC BASIS FOR GENERAL HYPEROSMIAHasin Y. 1 , Menashe I. 1 , Feldmesser E. 1 , Lancet D. 1 1 MolecularGenetics, Weizmann Institute of Science, Rehovot, IsraelSpecific anosmia has been amply described as the far end of agenetically determined bell-shaped distribution of individualsensitivities towards a given odorant. We suggest that innate generalanosmia similarly represents an extreme of a general olfactory thresholddistribution, which also includes general hyposmia, normosmia andhyperosmia. Our preliminary experiments have demonstratedsignificant concordance among human detection thresholds to sixodorants (Menashe et al, this volume), thus supporting the existence ofa common general olfactory sensitivity factor. We are exploring thegenetic basis of the entire general olfactory sensitivity curve, whichmay stem from genetic polymorphisms in olfactory signaling pathwaycomponents, such as Golf and adenylyl cyclase III. Our study isparticularly focused on general hyperosmia, since it has a lowerprobability of arising from non-genetic factors. Currently, wholegenome scans with Affymetrix 100k single nucleotide polymorphism(SNP) arrays are performed on hyperosmic subjects in comparison tohyposmic and normosomic controls. This will help to identify genomicregions which differ significantly in their SNP patterns between thegroups. In addition, we attempt to discover similar regions in the murinegenome. This can be done utilizing automated olfactometry, and therecently described in silico mapping method, based on a dense SNPmap in 48 inbred mouse strains (Pletcher et al., PLOS Biol 2(12): e393).Species comparisons, fine mapping and sequencing should allow theidentification of specific genes, which underlie human olfactoryvariability.334 Poster Chemosensory Molecular Genetics andVNO/PheromoneA NEW STRUCTURAL SUB-CLASS OF OLFACTORYRECEPTORSLai P.C. 1 , Bahl G. 2 , Clot-Faybesse O. 3 , Matarazzo V. 3 , Crasto C.J. 41 Molecular and Cell Biology, University of Connecticut, Storrs, CT;2 University of San Diego School of Medicine, San Diego, CA;3 Laboratoire de Neuroglycobiologie, L'Université de Provence,Marseille, Marseille, France; 4 Neurobiology, Yale University, NewHaven, CTRecognition of the mechanism of olfaction depends uponunderstanding the sequence-structure-function relationships of olfactoryreceptors. We used bioinformatics methods to identify a new structuralsub-class of olfactory receptors and GPCRs. We used availablestatistical methods to predict trans-membrane helical domains inolfactory receptor hOR17-210, a receptor that has been shown to bevariably functional and pseudogenic in humans. TM domainidentification was undertaken as a prelude to modeling this olfactoryreceptor in order to understand its interaction with ligands that havebeen experimentally shown to bind to this receptor. Our analysesrevealed that the N-terminus of this protein is intracellular and the C-terminus is extra-cellular. This reversed polarity in the termini does notdisrupt the positions of typical OR-motifs that initiate the signaltransduction process at the membrane. Our observations are contrary toconventional structural knowledge about ORs and GPCRs. Preliminarysequence analysis studies have shown that such a structure is observedin a limited number of olfactory receptors distributed across differentmammalian species. We present the results of the survey of all knownolfactory receptors and more than 15,000 proteins identified as GPCRs.We also present a methodology for modeling such olfactory receptors.When combined with experimental data, we believe that thisinformation will further our understanding of olfaction.335 Poster Chemosensory Molecular Genetics andVNO/PheromoneCHARACTERIZATION OF A NOVEL HUMAN TESTICULARODORANT RECEPTORTriller A. 1 , Schwane K. 1 , Riffell J.A. 2 , Panten J. 3 , Zimmer R.K. 4 , SpehrM. 5 , Hatt H. 1 1 Cell Physiology, Ruhr-University, Bochum, Germany;2 Neurobiology, University of Arizona, Tuscon, AZ; 3 RD Syntheses NewMolecules FRA, Symrise GmbH, Holzminden, Germany; 4 Ecology andEvolution, University of California, Los Angeles, CA; 5 Anatomy andNeurobiology, University of Maryland School of Medicine, Baltimore,MDIn addition to their conventional role in nasal chemodetection,members of the odorant receptor (OR) family have been attributed apotential function as molecular mediators of mammalian spermbehavior. Recently, we identified and characterized a human testicularOR, OR1D2 (alternate name: hOR17-4) that triggers chemotactic andchemokinetic responses in navigating sperm. Whether other putativesperm ORs control similar behavioral responses and whether thepopular `one cell–one receptor´ concept also applies to OR expressionin male gametes is currently unknown. Here, we report functionaldescription of a novel human testicular OR. Comparing the activationprofiles of both receptors in a recombinant expression system revealeddistinct non-overlapping receptive fields. Our findings thus provide atool to investigate individual OR-activated signaling mechanisms inmature sperm and determine their specific behavioral effects. Using acombination of calcium imaging and video motion analysis, on-goingstudies show that individual human sperm cells might express severalfunctional ORs which differentially trigger distinct signaling cascadesand behavioral responses. These results provide new insight into thephysiological principles that underlie OR-mediated sperm behaviors.Support: Deutsche Forschungsgemeinschaft (DFG)336 Poster Chemosensory Molecular Genetics andVNO/PheromoneHIGHTHROUGHPUT SCREENING SYSTEM FOROLFACTORY RECEPTORSSallmann F.R. 1 , Wilkin F. 1 , Philippeau M. 1 , Van Osselaer C. 1 , VeithenA. 1 1 ChemCom s.a., Brussels, BelgiumIn human, more than 380 olfactory receptor (OR) genes might berequired to account for the perception of several thousands of odorantmolecules. Exhaustive identification of ligands for each of these ORwould not only allow the understanding of odour recognition anddiscrimination but their use will also represent an essential industrialtool. It will help to discover and design new molecules, and optimize,refine or replace existing molecules by more potent, more appropriateand better protected ones. The design of specific antagonists might alsoallow to mask undesirable smells and achieve a better product profile.Screening programs and the construction of the human olfactory mapcan hardly be considered without a robust and reliable assaytechnology. Chemcom has set up screening procedures making use of aproprietary cell line allowing functional expression of ORs andcontaining an adapted reporter system. The assay was designed to runon a robotized platform, allowing the screening of large chemicallibraries on multiple OR´s. An automated single cell calcium imagingsystem has also been developed. This assay can be used to validateligand-receptor couples but also to screen numerous OR´s againstindividual ligands. Results obtained with both approaches are presented.This work was supported by the Brussels Region.84