Alternative splicing in individual Aplysia neurons generates neuropeptide diversity.

The neuron R15 is a peptidergic cell within the abdominal ganglion of Aplysia that participates in two neural circuits governing physiological and behavioral programs. We have cloned and characterized the major gene product expressed in this neuron. The R15 cDNA encodes a polyprotein precursor that is cleaved to yield a set of small neuropeptides. One peptide, R15 alpha 1, may act on different target cells to generate distinct but complementary physiological alterations that contribute to a program of cardiovascular changes in Aplysia. We have found that the RNA encoding the R15 polyprotein is spliced differently in different neurons. Our results suggest that alternative splicing of RNAs encoding polyproteins may provide a mechanism to generate distinct but overlapping sets of peptides that govern distinct but related physiological or behavioral programs.