Doshi, N. | bioRxiv Science

bioRxiv2019

Direct interaction of PIWI and DEPS-1 is essential for piRNA function and condensate ultrastructure in Caenorhabditis elegans

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.

cell biology↗

bioRxiv2019

Proximate causes and consequences of intergenerational influences of salient sensory experience.

Salient sensory environments experienced by a parental generation can exert intergenerational influences on offspring, including offspring not conceived at the time of the parental experience. While these data provide an exciting new perspective on biological inheritance, questions remain about causes and consequences of intergenerational influences of salient sensory experience. We have previously shown that exposing male mice to a salient olfactory experience like olfactory fear conditioning results in offspring demonstrating a sensitivity to the odor used to condition the paternal generation and possessing an enhanced neuroanatomical representation for that odor. In this study, we first injected RNA extracted from sperm of male mice that underwent olfactory fear conditioning into naive single cell zygotes and found that both male and female adults that develop from these embryos have increased sensitivity and enhanced neuroanatomical representation for the odor (Odor A) with which the paternal male had been conditioned. Next, we found that female, but not male offspring sired by males conditioned with Odor A show enhanced freezing when presented with Odor A after being exposed to a sub-threshold olfactory fear conditioning protocol that consisted of only a single Odor A + shock pairing. Our data provide evidence that RNA found in the paternal germline after exposure to salient sensory experiences can contribute to intergenerational influences of such experiences, and that such intergenerational influences confer an element of adaptation to the filial generation. In so doing, our work suggests that some causes (sperm RNA) and consequences (behavioral flexibility) of intergenerational influences of parental experiences are conserved across experiences as diverse as stressors, dietary manipulations, and sensory experiences.

zoology↗