Molecular analysis of a novel FMRFamide-related peptide gene (SOFaRP2) and its expression pattern in the brain of the European cuttlefish Sepia officinalis

► We cloned a novel FMRFamide-related peptides (FaRPs) gene which encodes four FaRPs. ► All but TIFRFamide were found to induce chromatophore expansion in an in vitro assay. ► We found that SOFaRP2 gene is expressed in cuttlefish brain regions regulating chromatophore activities. FMRFamide-related peptides (FaRPs) are among several neurotransmitters known to regulate the chromatophore function in the European cuttlefish Sepia officinalis. Here we report the cloning and sequencing of a novel S. officinalis FaRP gene (SOFaRP2). The complete 835-base pair cDNA sequence of the SOFaRP2 gene contains an open reading frame of 567 base pairs encoding 188 amino acids and four putative FaRPs, NSLFRFamide, GNLFRFamide, TIFRFamide and PHTPFRFamide. All except TIFRFamide cause chromatophore expansion when assayed in an in vitro chromatophore bioassay. To investigate the expression pattern of SOFaRP2 gene in the cuttlefish brain, in situ hybridization was performed using a full length RNA probe. The SOFaRP2 gene was expressed primarily in the posterior chromatophore, anterior chromatophore, lateral basal and optic lobes among other brain locations. The SOFaRP2 gene appears to be expressed in all brain regions involved in chromatophore regulation. These data suggests that some or all of the four FaRPs encoded by SOFaRP2 might be involved in controlling chromatophore activity in cuttlefish.