Gene structure analysis of kisspeptin-2 () in the Senegalese sole (): Characterization of two splice variants of , and novel evidence for metabolic regulation of kisspeptin signaling in non-mammalian species

Overview & Synopsis

Kisspeptin signaling in the brain is involved in the control of the onset of puberty in vertebrates. In this study, we present novel evidence indicating that kisspeptin may link energy balance and reproduction. For that purpose, we determined the complete gene structure of kisspeptin in a teleost fish, the Senegalese sole (Ss). In contrast to the situation evident in several fish, in this species only Kiss2 was found. Yet, two Ss isoforms generated by alternative splicing through intronic retention were detected: Ss , producing the functional protein, and Ss , coding for a truncated, non-functional protein. Specific qPCRs showed that the expression of these two isoforms varied differently in brain and gonads throughout maturation. In addition, and in contrast to what has been observed in mammals, fasting increased hypothalamic mRNA levels of Ss , which also caused a concomitant rise in pituitary Ss and Ss mRNA. Together, these data indicate the impact of the nutritional status on mRNA expression as a potential regulatory mechanism for the metabolic control of reproduction in non-mammalian species, albeit with some significant differences with respect to the situation described in mammals.