BMP-regulated exosomes from Drosophila male reproductive glands reprogram female behavior.
Bottom Line: Male reproductive glands secrete signals into seminal fluid to facilitate reproductive success.Exosome release was required to inhibit female remating behavior, suggesting that exosomes are downstream effectors of BMP signaling.These results demonstrate a new function for the MVB-exosome pathway in the reproductive tract that appears to be conserved across evolution.
Affiliation: Department of Physiology, Anatomy and Genetics and Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX1 3QX, England, UK.Show MeSH
Related in: MedlinePlus
License 1 - License 2
Mentions: To assess whether CD63-GFP–positive puncta in the AG lumen are exosomes derived from mMVBLs of SCs, we specifically blocked expression or function of a broad range of molecules in SCs, which in other systems are implicated in exosome biogenesis. The ESCRT complex has well-characterized roles in ILV formation, although ESCRT-independent mechanisms have also been reported (Trajkovic et al., 2008). Hrs is a component of the ESCRT-0 complex directly involved in protein sorting into ILVs and ILV formation through subsequent recruitment of downstream ESCRTs (Lloyd et al., 2002; Katzmann et al., 2003). Several recent studies demonstrate a role for Hrs in ESCRT-dependent exosome secretion in mammals and flies (Tamai et al., 2010; Gross et al., 2012; Colombo et al., 2013). ALiX (ALG-2–interacting protein X) interacts with several ESCRT complex proteins (Matsuo et al., 2004; Odorizzi, 2006). Recent knockdown studies in mammalian cells indicate that it is required in exosome biogenesis (Matsuo et al., 2004; Baietti et al., 2012), but this has not been investigated in flies. Fluorescent ILVs inside mMVBLs were almost completely absent in SCs expressing either Hrs-RNAi or ALiX-RNAi constructs, unlike controls (Fig. 5, B–D). The number of CD63-GFP–positive puncta secreted into the AG lumen was also drastically reduced (P < 0.001, n > 9; Fig. 5 A). mMVBLs in ALiX-RNAi– and Hrs-RNAi–expressing SCs were smaller and larger than controls, respectively (Fig. 5 I). These genotypes had normal numbers of iLEs (Fig. 5 H), but Hrs-RNAi–expressing SCs had significantly fewer mMVBLs (Fig. 5 G). Importantly, these ESCRT knockdown SCs still synthesized equivalent levels of the SC-specific CD63-GFP fusion protein by Western blot analysis of whole glands (Fig. 5 J) but transferred much less protein to females upon mating (Fig. 5 K), consistent with the reduced secretion of this exosome marker.
Affiliation: Department of Physiology, Anatomy and Genetics and Nuffield Department of Surgical Sciences, University of Oxford, Oxford OX1 3QX, England, UK.