An FMRFamide Neuropeptide in Cuttlefish : Identification, Characterization, and Potential Function.

Neuropeptides are released by neurons that are involved in a wide range of brain functions, such as food intake, metabolism, reproduction, and learning and memory. A full-length cDNA sequence of an gene isolated from the cuttlefish (designated as ) was cloned. The predicted precursor protein contains one putative signal peptide and four FMRFamide-related peptides. Multiple amino acid and nucleotide sequence alignments showed that it shares 97% similarity with the precursor FMRFamides of and and shares 93% and 92% similarity with the gene of the two cuttlefish species, respectively. Moreover, the phylogenetic analysis also suggested that FMRFamide and FMRFamides from and belong to the same sub-branch. Tissue expression analysis confirmed that was widely distributed among tissues and predominantly expressed in the brain at the three development stages. The combined effects of FMRFamide+GnRH and FLRFamide+GnRH showed a marked decrease in the level of the total proteins released in the CHO-K1 cells. This is the first report of in and the results may contribute to future studies of neuropeptide evolution or may prove useful for the development of aquaculture methods for this cuttlefish species.