RT Journal Article
SR Electronic
T1 Direct interaction of PIWI and DEPS-1 is essential for piRNA function and condensate ultrastructure in <em>Caenorhabditis elegans</em>
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 580043
DO 10.1101/580043
A1 KM Suen
A1 F Braukmann
A1 R Butler
A1 D Bensaddek
A1 A Akay
A1 C. -C Lin
A1 N Doshi
A1 A Sapetschnig
A1 A Lamond
A1 JE Ladbury
A1 EA Miska
YR 2019
UL http://biorxiv.org/content/early/2019/03/16/580043.abstract
AB Membraneless organelles are platforms for many aspects of RNA biology including small non-coding RNA (ncRNA) mediated gene silencing. How small ncRNAs utilise phase separated environments for their function is unclear. To address this question, we investigated how the PIWI-interacting RNA (piRNA) pathway engages with the membraneless organelle P granule in Caenorhabditis elegans. Proteomic analysis of the PIWI protein PRG-1 revealed an interaction with the constitutive P granule protein DEPS-1. Furthermore we identified a novel motif on DEPS-1, PBS, which interacts directly with the Piwi domain of PRG-1. This protein complex forms intertwining ultrastructures to build elongated condensates in vivo. These sub-organelle ultrastructures depend on the Piwi-interacting motif of DEPS-1 and mediate piRNA function. Additionally, we identify a novel interactor of DEPS-1, EDG-1, which is required for DEPS-1 condensates to form correctly. We show that DEPS-1 is not required for piRNA biogenesis but piRNA function: deps-1 mutants fail to produce the secondary endo-siRNAs required for the silencing of piRNA targets. Our study reveals how specific protein-protein interactions drive the spatial organisation and function of small RNA pathways within membraneless organelles.