Antisera to multiple antigenic peptides detect neuropeptide processing.

Peptides act as critical messengers of essential physiological function. Frequently, several peptides are encoded in the same precursor and, often, there is structure relatedness among the gene products. The complexity of protein precursors and presence of homologous peptides raises issues about regulation of gene expression and function of structurally-related peptides. We have determined the cellular location of DPKQDFMRFamide and SDNFMRFamide encoded in the Drosophila FMRFamide gene. We raised antisera that distinguish between the two peptides and conducted double label immunostaining utilizing antisera raised in the same host species. We found that DPKQDFMRFamide and SDNFMRFamide are present in distinct distribution patterns. We also established that the peptides are present in cells stained by FMRFamide antisera. Thus, our data are consistent with the conclusion that Drosophila contains cell-specific proteolytic processing enzymes capable of posttranslationally cleaving a polypeptide protein precursor to yield unique expression patterns of neuropeptides that may have diverse activities.