Heterogeneous dissociation process of truncated RNAs by oligomerized Vasa helicase

Yoshimi Kinoshita,Shintaroh Kubo,Ryo Murakami,Sotaro Uemura,Nao Muto,Ryo Iizuka

doi:10.1038/s42003-021-02918-0

Yoshimi Kinoshita, Shintaroh Kubo + Show 4 more

Open Access

https://doi.org/10.1038/s42003-021-02918-0

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Journal: Communications Biology	Publication Date: Dec 1, 2021
Citations: 2	License type: open-access

Affiliation: The University of Tokyo, Kyoto University

Abstract

RNA helicases are enzymes that generally unwind double-stranded RNA using ATP hydrolysis energy, mainly involved in RNA metabolism, transcription, translation, and mRNA splicing. While the helicase core is crucial for RNA unwinding activity, N- and C-terminal extensions of specific helicases may contain an intrinsically disordered region for electrostatic interaction, resulting in the formation of droplets in the cytoplasm. However, how the disordered region of the RNA helicase contributes to RNA unwinding and dissociation remains unclear. Here, we focused on Bombyx mori Vasa, which unwinds truncated target transposon RNAs from the piRNA-induced silencing complex piRISC. In this study, we used single-molecule techniques to visualise how Vasa dynamically interacts with piRISC and investigate how Vasa oligomerization is involved in the process of piRNA amplification, named the ping-pong pathway. We found that Vasa’s oligomerization is required during these processes in vitro and in vivo, and that Vasa triggers the dissociation of truncated RNA in heterogeneous pathways. Our single-molecule results suggest that oligomerized Vasa guides the timing of the process regulating overall dissociation efficiency.

Highlights

RNA helicases are enzymes that generally unwind double-stranded RNA using ATP hydrolysis energy, mainly involved in RNA metabolism, transcription, translation, and mRNA splicing
DEAD-box RNA helicases are the largest helicase family involved in all aspects of RNA metabolism, including transcription, translation, and mRNA splicing[1]
While the helicase core is crucial for RNA unwinding, the N- and C-terminal extensions of specific helicases have a unique function

Summary

Introduction

RNA helicases are enzymes that generally unwind double-stranded RNA using ATP hydrolysis energy, mainly involved in RNA metabolism, transcription, translation, and mRNA splicing. The number of Vasa molecules in association and dissociation was calculated to be 2.13 ± 0.17 and 2.48 ± 0.25, respectively (Fig. 1e), indicating that the dynamics of aggregation occurred in the dimer unit. The results showed that in the presence of WT-Vasa, target RNA complementary to endogenous piRNA was dissociated from the beads bound to Siwi-piRISC (Fig. 2a).

Results

Conclusion