Identification, expression, and characterization of splice variants in the kisspeptin system in the Senegalese sole (Solea senegalensis)

Abstract

The Kisspeptin system plays an important role in the onset of puberty in vertebrates including fishes. This system includes several orthologs and paralogs of the Kisspeptin genes (Kiss) and of its receptor (Kiss1r). Cloning of the full coding region of both genes in an aquacultured fish, the Senegalese sole (Solea senegalensis) (Ss), revealed unexpected features of these genes. For the first time in vertebrates two splice variants were detected, which originated by intron retention in both the Kiss and Kiss1r. However, no paralog genes were found in this species. Analysis of both retained introns showed several features characteristic of an alternative splicing mechanism. Interestingly, the two splice variants showed distinct expression patterns according to the different stages of sexual maturation. In conclusion, presence of alternative splice variants on the kisspeptin ligand and receptor in vertebrates may contribute to our understanding of the regulation kisspeptin- KISS1R signaling