Comparative study of pineal clock gene and AANAT2 expression in relation to melatonin synthesis in Atlantic salmon (Salmo salar) and European seabass (Dicentrarchus labrax)

Atlantic salmon showed no rhythmic expression of the melatonin-synthesizing gene Aanat2, while European seabass exhibited circadian Aanat2 expression.

• The pineal gland in teleost fish is important for producing melatonin, which regulates biological rhythms.
• Different teleost species may have distinct mechanisms controlling melatonin production, influenced by both internal and external signals.
• In Atlantic salmon, rhythmic expression of certain clock genes was not observed in vitro, suggesting limited clock regulation in this context.
• In vivo studies revealed rhythmic expression of some clock genes in Atlantic salmon, indicating potential external regulation.
• European seabass displayed circadian expression of Aanat2, highlighting species-specific differences in melatonin production regulation.
• Genomic analysis indicated that the regulatory sequences of Aanat2 in Atlantic salmon differ from those in European seabass and other teleosts, suggesting a loss of functional regulation.

AI simplified