Researcher(s)
- Jessica Rauch, , University of Delaware
Faculty Mentor(s)
- Jessica Tanis, Biological Sciences, University of Delaware
Abstract
Extracellular vesicles (EVs) are bioactive molecular signaling structures enclosed by a lipid bilayer that mediate intercellular communication by transporting proteins, RNA, lipids, and metabolites between cells. Although EVs are known to play critical roles in both normal physiology and disease, the mechanisms controlling their biogenesis and release remain incompletely understood. In Caenorhabditis elegans, sensory neurons within the male tail shed two distinct subpopulations of EVs from separate compartments of the cilia: the distal tip, which releases EVs containing the TRP channel PKD-2, and the ciliary base, which releases EVs containing the ion channel CLHM-1. Interestingly, previous findings suggest that the small GTPase RAB-28 may differentially regulate these EV subpopulations.
A 2019 study by Akella et al. reported that a rab-28 mutation caused accumulation of EVs between the cilium and surrounding glia, suggesting a potential role in promoting EV shedding. However, subsequent observations in a different rab-28(gk1040) allele revealed a reduction in CLHM-1-containing EVs, with no effect on PKD-2 EVs. This unexpected effect raises questions about the precise role of RAB-28 in regulating distinct EV subpopulations.
To address this, I performed a genetic cross between the rab-28(tm2636) mutant and strains expressing CLHM-1::GFP and MKS-2::mScarlet, with him-5 to facilitate male enrichment. My goal was to generate a strain that will enable high-resolution imaging and quantification of CLHM-1 EV release. Over the summer, I was able to complete and verify the successful cross through genotyping via gel electrophoresis and screening of transgenes. I have been trained to use the dragonfly spinning disc confocal which will enable me to visualize the distribution of our cargoes of interest within the primary cilium of the male tails.
These experiments aim to clarify whether RAB-28 plays a role in promoting or restricting EV release, and whether this function is context-dependent based on the sub-cellular origin of the vesicles. A better understanding of this regulatory mechanism could shed light on conserved pathways that govern EV-mediated signaling across species.