The Female Post-Mating Response Requires Genes Expressed in the Secondary Cells of the Male Accessory Gland inDrosophila melanogaster

Abstract

Seminal proteins from the Drosophila male accessory gland induce post-mating responses (PMR) in females. The PMR comprise behavioral and physiological changes that include increased egg laying, decreased receptivity to courting males, and changes in the storage and use of sperm. Many of these changes are induced by a "sex peptide" (SP) and are maintained by SP's binding to, and slow release from, sperm. The accessory gland contains two secretory cell types with distinct morphological and developmental characteristics. Products of these "main" and "secondary" cells work interdependently to induce and maintain the PMR. To identify individual genes needed for the morphology and function of secondary cells, we studied iab-6 cocu males, whose secondary cells have abnormal morphology and fail to provide products to maintain the PMR. By RNA-seq, we identified 77 genes that are downregulated by a factor of .53 in iab-6 cocu males. By functional assays and microscopy, we tested 20 candidate genes and found that at least 9 are required for normal storage and release of SP in mated females. Knockdown of each of these 9 genes consequently leads to a reduction in egg laying and an increase in receptivity over time, confirming a role for the secondary cells in maintaining the long-term PMR. Interestingly, only 1 of the 9 genes, CG3349, encodes a previously reported seminal fluid protein (Sfp), suggesting that secondary cells may perform essential functions beyond the production and modification of known Sfps. At least 3 of the 9 genes also regulate the size and/or abundance of secondary cell vacuoles, suggesting that the vacuoles' contents may be important for the machinery used to maintain the PMR.

Rab‐mediated trafficking in the secondary cells of Drosophila male accessory glands and its role in fecundity

“…This resource provides annotations based on a defined vocabulary for each Rab protein expressed in AGs and allows 3D localization tracking down to subcellular resolutions. Thus, our work maps out the maturation of the membrane/protein transport machinery in the AGs over time and adds valuable knowledge to the existing model describing the SC secretion system …”

“…The VLCs are membrane‐bound organelles containing a large internal space. The SCs, like the MCs, are in direct contact with the glandular lumen and are able to contribute to the seminal fluid . Recent findings show that the SCs, however, are not crucial for initiating PMR behaviors.…”

“…Recent findings show that the SCs, however, are not crucial for initiating PMR behaviors. Instead, through genetic manipulations that affect SCs and/or their VLCs, SCs have been shown to play a critical role in sustaining the female PMR for up to 10 days after mating . Given their prominence in SC architecture, the biological function of VLCs seems to be key to understanding how SCs function in sustaining the PMR.…”

Nutrient conditions sensed by the reproductive organ during development optimize male fecundity in Drosophila

“…Targeted inhibition of TOR signaling in the accessory gland (dG30A > TOR [DN]), as well as Abd-B mutant cells, resulted in size reduction in SCs associated with defective vacuolar formation. It seems likely that Abd-B is a nutrient-responsive transcription factor that regulates the maturation of the SCs, which is essential for male fecundity (Gligorov et al, 2013;Sitnik, Gligorov, Maeda, Karch, & Wolfner, 2016). It seems likely that Abd-B is a nutrient-responsive transcription factor that regulates the maturation of the SCs, which is essential for male fecundity (Gligorov et al, 2013;Sitnik, Gligorov, Maeda, Karch, & Wolfner, 2016).…”

“…The candidate genes for factor X secreted from SCs are Abd-B target genes (Sitnik et al, 2016) | 565 (GAL80 ts ) strain was used (McGuire, Le, Osborn, Matsumoto, & Davis, 2003). From late pupal to adult stages, growth of the accessory gland (main cells) largely depends on the insulin signaling pathway.…”