%0 Journal Article %T Analysis of the goldfish Carassius auratus olfactory epithelium transcriptome reveals the presence of numerous non-olfactory GPCR and putative receptors for progestin pheromones %A Nikolay N Kolmakov %A Michael Kube %A Richard Reinhardt %A Adelino VM Canario %J BMC Genomics %D 2008 %I BioMed Central %R 10.1186/1471-2164-9-429 %X We generated 4,797 high quality sequences from a normalized cDNA library of the goldfish olfactory epithelium, which were clustered in 3,879 unique sequences, grouped in 668 contigs and 3,211 singletons. BLASTX searches produced 3,243 significant (E-value < e-10) hits and Gene Ontology (GO) analysis annotated a further 1,223 of these genes (37.7%). Comparative analysis with zebrafish olfactory epithelium ESTs revealed 1,088 identical unigenes. The transcriptome size of both species was estimated at about 16,400 unigenes, based on the proportion of genes identified involved in Glucose Metabolic Process. Of 124 G-protein coupled receptors identified in the olfactory epithelium of both species, 56 were olfactory receptors. Beta and gamma membrane progestin receptors were also isolated by subcloning of RT-PCR products from both species and an olfactory epithelium specific splice form identified.The high similarity between the goldfish and zebrafish olfactory systems allowed the creation of a 'cyprinid' olfactory epithelium library estimated to represent circa 70% of the transcriptome. These results are an important resource for the identification of components of signalling pathways involved in olfaction as well as putative targets for pharmacological and histochemical studies. The possible function of the receptors identified in the olfactory system is described. Moreover, the role of olfactory epithelium specific isoforms of classical membrane progestin receptor genes as candidates for preovulatory pheromone sensing is discussed.Chemical senses play an important role in aquatic organisms, affecting many aspects of their biology. In teleost fish, social behaviour, reproduction, homing, schooling, search for food and predator avoidance are all regulated by the sense of smell [1-3]. In addition, because of its origin and structure, the olfactory epithelium is the first tissue to be affected by any toxic agent that fish encounter in the natural environment [4,5] and heavy %U http://www.biomedcentral.com/1471-2164/9/429