Molecular and genetic analyses of Sex-Peptide action in Drosophila melanogaster. J-B. Peyre 1, T. Aigaki 1,2. 1) Biology Dept, Tokyo Metropolitan University, Tokyo, Japan; 2) PRESTO, JRDC.
The Sex-Peptide (SP) produced in the male accessory glands plays a crucial role in Drosophila reproduction. It is transferred as a component of seminal fluid into females, where it induces ovulation and male rejection behavior. Although previous experiments have suggested that specific nervous system subsets are involved in SP responses, its mode of action has not yet been elucidated. To understand the mechanisms of SP actions and highlight its target tissues, we have traced it by using GFP as a tag. Using the Gal4-UAS system, we assessed the activity of the various fusion proteins on SP responses by expressing them in virgin females. Fusion constructs containing SP AA 8 to 36 triggered SP responses, whereas those containing AA 1-8 did not. Acp26Aa-Gal4 line was used to drive expression in accessory glands of transgenic males; using Oregon-R females mated with those males, we observed specific endocytosis of active fusion proteins in female common oviduct and uterus cells. Pericardial cells also accumulated all the fusion proteins. Endocytosis of active GFP-SP fusions also occurred in the male ejaculatory duct cells after mating, so SP could have some effects on the mated males as well. Ectopic expression of SP induced a wide range of phenotypes: Depending on the Gal4 lines used, we observed lethality and developmental defects, as well as increased grooming, bisexual courtship and learning defects in males. ebony mutation enhanced SP phenotypes, and SP expression triggered changes in monoamine levels. Based on these observations, we tested and found genetic interactions between SP and genes involved in monoamines metabolism ( Ddc, ple , Punch, Dat, svr, qs), genes regulating cellular vesicles (hk, shi, stnA, dor, g, ltd), and other associated genes (bw, w, cn, ry). Altogether, these results suggest that Sex-Peptide interacts with vesicular protein complexes, which in turn regulate vesicle trafficking, and nervous system activity through synaptic vesicles.