1 1 Symposium Chemosensory Receptors Satellite DEVELOPMENT ...

341 Poster Chemosensory Molecular Genetics andVNO/PheromoneCHANGES IN OLFACTORY RECEPTOR EXPRESSION INAGING MICELee A.C. 1 , Tian H. 1 , Ma M. 1 1 Neuroscience, University ofPennsylvania, Philadelphia, PAOlfactory perception deteriorates in mammals with age, which isaccompanied by structural and molecular changes along the olfactorypathway including the olfactory epithelium, the olfactory bulb, and theolfactory cortex. Previous studies have shown that the mainpathological change in the nose during aging is the reduction of theolfactory epithelial surface (area and thickness), and a net loss of matureolfactory sensory neurons. Odorant receptors (ORs) expressed in theepithelium are critical for smell, but it is not known how theirexpression levels change with age. In this study, we investigatedchanges in olfactory receptor expression by performing in situhybridization for representative ORs selected from all four zones. Thedensity of olfactory sensory neurons expressing particular ORs wascompared at ages of 1, 12, and 18 months. The expression of somereceptors decreased, while others increased. For example, the density ofMOR267-16 neurons decreased from 4,120 ± 781 cells/mm 3 at 1 monthto 2,784 ± 601 cells/mm 3 at 18 months. In contrast, the density ofMOR235-1 neurons increased from 8,836 ± 1501 cells/mm 3 at 1 monthto 12,954 ± 273 cells/mm 3 at 18 months. The results indicate that agerelatedolfactory deterioration is more complex than the simple loss ofolfactory receptors. This work is supported by NIDCD/NIH, WhitehallFoundation and UPenn IOA (Pilot Grant).342 Poster Chemosensory Molecular Genetics andVNO/PheromoneSIGNATURES OF AGING: PROFILES OF GENEREGULATION IN THE MURINE OLFACTORY EPITHELIUMGetchell T.V. 1 , Hersh M.A. 2 , Vaishnav R.A. 1 , Saunders C.P. 2 , Liu H. 2 ,Stromberg A.J. 2 , Getchell M.L. 3 1 Physiology, University of Kentucky,Lexington, KY; 2 Statistics, University of Kentucky, Lexington, KY;3 Anatomy & Neurobiology, University of Kentucky, Lexington, KYWe are investigating age-related changes in gene regulation in themurine olfactory system at 3 representative ontogenic stages: the 1.5month (mo) young adult, the 6.0 mo adult, and the 20 mo old adult.Following total RNA isolation from the olfactory epithelium (OE) of 3age-matched male mice at each stage, cDNAs from each mouse werehybridized on 9 Affymetrix 430 2.0 whole mouse genome GeneChips.After data scrubbing and ANOVA, 3,840 known genes had significantdifferences (p < 0.01) in their mean hybridization signals between atleast 2 stages. We used 2 methods of informatics analysis to identifysignatures of gene regulation associated with aging. First, theExpression Analysis Systematic Explorer (EASE) program identifiedseveral Gene Ontology categories associated with cellular proliferationas being over-represented (EASE scores of < 0.05) and down-regulated.Second, post-hoc statistical comparisons identified 136 significantlyregulated genes (p < 0.01) that exhibited 1 of 3 characteristic temporalprofiles. There were 15 genes that were up-regulated with increasingage, 30 genes that were down-regulated with increasing age, and 91genes that had mixed patterns. The results of our study have identifiedspecific molecular and pattern profiles of gene regulation that establishsignatures of aging in the murine olfactory epithelium. Support: NIH-AG16824 (TVG), NIH-T32-CD00065 (CS), NIH-IP20-RR-16481(AJS)343 Poster Chemosensory Molecular Genetics andVNO/PheromoneAN INTEGRATED OLFACTORY RECEPTOR MICROARRAYGENE EXPRESSION DATABASELiu N. 1 , Yang J. 1 , Crasto C.J. 1 , Firestein S. 2 , Ma M. 3 1 Center forMedical Informatics, Yale University, New Haven, CT; 2 Biology,Columbia University, New York, NY; 3 Neuroscience, University ofPennsylvania, Philadelphia, PAAims: The olfactory receptor gene expression pattern is an importantcomponent of signal encoding mechanisms in the mammalian olfactorysystem. We have developed the Olfactory Receptor MicroarrayDatabase (ORMD; http://neurolab.med.yale.edu/ormd/) to house ORgene expression data and have integrated the database with theSenseLab system, in particular, ORDB (http://senselab.med.yale.edu/senselab/ORDB/). Methods: ORMD is a Web-based database, built inJava and Oracle. This is a secure database, which requires anauthenticated login to access private data. Data contributors may definethe public availability of individual datasets. Results: ORMD allowsusers to manage projects/experiments and to deposit related geneexpression data. For each experiment, raw data files can be downloadedand analyzed gene expression data can be viewed or exported. For eachprobe set, a hyperlink is provided to directly access the related olfactoryreceptor in ORDB. On the other hand, hyperlinks are provided inORDB for individual receptors, allowing Web visitors to access therelated microarray data in ORMD. Conclusions: 1. ORMD willfacilitate microarray study of olfactory receptor gene expression; 2.Together with ORDB in SenseLab, ORMD integrates gene expressiondata with genomics data for the olfactory receptors, providing resourcesfor database users as well as the public. Acknowledgments: Supportedby the NIH Human Brain Project and National Library of Medicine.344 Poster Chemosensory Molecular Genetics andVNO/PheromoneCHROMATIN STRUCTURE AT ODORANT RECEPTOR LOCIKambere M. 1 , Getman M. 1 , Lane R.P. 1 1 Molecular Biology andBiochemistry, Wesleyan University, Middletown, CTThe mammalian olfactory system is able to detect and distinguishamong tens of thousands of odorants in the environment. This ability isdependent on an organizing principle in which each sensory neuron inthe nose expresses only one olfactory receptor (OR) allele from among>1000 OR genes in the genome. We are interested in understanding theregulatory mechanisms that govern this mutually exclusive expression.Previous genomic and genetic studies suggest that OR genes reside inrepressed regions of the genome, and we are exploring the hypothesisthat mutually exclusive transcription of only one OR allele is facilitatedby limiting transcriptional access by chromatin modifications. We haveused chromatin immunoprecipitation (ChIP) assays to generatepreliminary results on the histone modifications at an OR locus that wehave previously shown becomes active in a differentiated olfactorysensory cell line. For all six modifications tested, histones around thetested OR locus in undifferentiated cells show acetylation andmethylation patterns consistent with inactive euchromatin. This resultsuggests that the ground state for OR loci in premature sensory neuronsis “closed”. We are now assaying histone acetylation and methylationpatterns at multiple OR loci to test whether all OR genes are similarly“closed” in undifferentiated cells, and investigating how chromatinpatterns change during the differentiation process. We anticipate havingpreliminary results for these studies by the date of this meeting.86