AN IMMUNOCYTOCHEMICAL STUDY OF THE FMRFAMIDE NEUROPEPTIDE GENE-PRODUCTS IN DROSOPHILA

We have mapped protein expression of the FMRFamide neuropeptide gene i n Drosophila with polyclonal antisera against three small peptides who se sequences were derived from the Drosophila proFMRFamide precursor. One antiserum was affinity-purified and extensively characterized. The enriched antibodies labeled 15-21 bilaterally symmetric pairs of neur ons in a pattern that corresponded very closely to the pattern of in s itu hybridization that was determined previously (Schneider et al. [19 91] J. Comp. Neurol. 304:608-622; O'Brien et al. [1991] J. Comp. Neuro l. 304:623-638). The other antisera produced complementary results. Th ese findings suggest that the antisera specifically label cells that e xpress the FMRFamide gene. In larvae we consistently observed, strong staining in identified interneurons and neuroendocrine cells, and mode rate to weak staining in neurons of unknown function. The adult patter n of expression included both larval neurons whose immunoreactivity pe rsisted through metamorphosis and adult-specific neurons. During metam orphosis, we observed transient staining in a small number of neurons and in specific neuropil regions that included the central body, the p rotocerebral bridge, and the optic ganglia. Based on these morphologic al features, we suggest that the FMRFamide-like neuropeptides in Droso phila play a number of functional roles, perhaps affecting both physio logical and developmental phenomena. Such roles include general modula tion throughout all post-embryonic stages, via the blood, and also mor e stage- and region-specific modulation within the CNS. (C) 1993 Wiley -Liss, Inc.