NEUROPEPTIDES ANALYSIS OF OCTOPUS VULGARIS TRANSCRIPTOME: OCT-PEDAL PEPTIDE EXPRESSION IN CNS LOBES INVOLVED IN MOTOR COORDINATION

The discovery of novel peptides and hormones from the phylum Mollusca, enabled by the availability of whole genomes, transcriptomes and peptidomes, gives now ample tools for studying the structural evolution of peptides and hormones, and for redefining the phylogenetic relationships of key families of peptide and hormones across ecdysozoans, lophotrochozoans and chordates. In this frame, the genome sequence of the limpet Lottia gigantea (Veenstra, 2010) and the initiated large-scale molluscan transcriptome and genome projects (Moroz et al., 2011; De Lisa et al., 2011; Di Cosmo and Polese, 2012) offer an excellent opportunity to look at the neuropetides and neurohormone genes. Mollusks have several genes coding pedal peptides (PP), three in Lottia and four in Aplysia (Veenstra, 2010). Neuropeptides are the fastest evolving intercellular signals; in particular, cephalopods developed a number of specific innovations in their repertoire of secretory molecules that might supp ort their unique features (Moroz, 2011). Using neuronal transcriptome from Octopus vulgaris, we developed a specific probe to analyze expression of Oct-PP in O. vulgaris brain in horizontal sections throughout the suboesophageal and supraoesophageal masses, including optic lobes. Performing ISH analysis we found the expression of Oct-PP mRNA confined in the anterior suboesophageal mass, in the prebrachial lobe and in the middle suboesophageal mass, in all pedal lobes. The prebrachial lobe is involved in reflex coordination. The middle suboesophageal mass, representative of the pedal ganglionated cord of early mollusks, is involved in all actions in Octopus (Young, 1971). Our findings support the involvement of Oct-PP in reflex and motor coordination in Octopus.