title: Identification of a uniquely expanded V1R (ORA) gene family in the Japanese grenadier anchovy (Coilia nasus).
abstract: A number of studies have suggested that olfaction plays an important role in fish migration. Fish use several distinct families of olfactory receptors to detect environmental odorants, including MORs (main olfactory receptors), V1Rs (vomeronasal type-1 receptors), V2Rs (vomeronasal type-2 receptors), TAARs (trace amine-associated receptors), and FPRs (formyl peptide receptors). The V1Rs have been reported to detect pheromones, and a pheromone hypothesis for the spawning migration of anadromous fish has been proposed. Examining whetherCoilia nasusrelies on V1R-mediated olfaction for spawning migration is important for understanding the molecular basis of spawning migration behavior. Here, we explored the V1R gene family in anadromousC. nasus. Six V1R genes previously reported in other teleost fish were successfully identified. Interestingly, we detected the largest V1R repertoire in teleost fish fromC. nasusand identified a species-specific expansion event of V1R3 gene that has previously been detected as single-copy genes in other teleost fish. The V1R loci were found to be populated with repetitive sequences, especially in the expanded V1R3 genes. Additionally, the divergence of V1R3 genetic structures in different populations ofC. nasusindicates the copy number variation (CNV) in V1R3 gene among individuals ofC. nasus. Most of the putativeC. nasusV1R genes were expressed primarily in the olfactory epithelium, consistent with the role of the gene products as functional olfactory receptors. Significant differences in the expression levels of V1R genes were detected between the anadromous and non-anadromousC. nasus. This study represents a first step in the elucidation of the olfactory communication system ofC. nasusat the molecular level. Our results indicate that some V1R genes may be involved in the spawning migration ofC. nasus, and the study provides new insights into the spawning migration and genome evolution ofC. nasus.
authors.affiliation: College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China.
authors.forename: Guoli
authors.initials: G
authors.lastname: Zhu
authors.affiliation: College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China.
authors.forename: Wenqiao
authors.initials: W
authors.lastname: Tang
authors.affiliation: Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina USA.
authors.forename: Liangjiang
authors.initials: L
authors.lastname: Wang
authors.affiliation: College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Wang
authors.affiliation: College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China.
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Wang