NOVEL GENE HCS1 SPECIFICALLY EXPRESSED IN THE GIANT INTERNEURONS OF THE TERRESTRIAL SNAIL

THE terrestrial snail Helix lucorum is a promising model for molecular neurobiology since its central nervous system (CNS) is simple and con tains many morphologically and functionally identified large neurones. Among these, the giant interneurones located in pleural and parietal ganglia are especially interesting because they trigger the withdrawal behaviour of the snail and participate in aversive conditioning. Here we describe the identification and characterization of a gene named H CS1 which is preferentially expressed in these interneurones. It encod es a putative protein 100 amino acids long containing an N-terminal hy drophobic leader peptide. No sequences with significant homology to HC S1 were found in the protein (Swiss-Prot) and nucleotide (EMBLbank) da ta libraries. We suppose that the product of this gene is a secreted p rotein, presumably a neuropeptide or a growth factor.