Loquacious-PD facilitates Drosophila Dicer-2 cleavage through interactions with the helicase domain and dsRNA.

Abstract

Loquacious-PD (Loqs-PD) is required for biogenesis of many endogenous siRNAs in Drosophila In vitro, Loqs-PD enhances the rate of dsRNA cleavage by Dicer-2 and also enables processing of substrates normally refractory to cleavage. Using purified components, and Loqs-PD truncations, we provide a mechanistic basis for Loqs-PD functions. Our studies indicate that the 22 amino acids at the C terminus of Loqs-PD, including an FDF-like motif, directly interact with the Hel2 subdomain of Dicer-2's helicase domain. This interaction is RNA-independent, but we find that modulation of Dicer-2 cleavage also requires dsRNA binding by Loqs-PD. Furthermore, while the first dsRNA-binding motif of Loqs-PD is dispensable for enhancing cleavage of optimal substrates, it is essential for enhancing cleavage of suboptimal substrates. Finally, our studies define a previously unrecognized Dicer interaction interface and suggest that Loqs-PD is well positioned to recruit substrates into the helicase domain of Dicer-2.

DOI: 10.1073/pnas.1707063114

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Cite this paper

@article{Trettin2017LoquaciousPDFD, title={Loquacious-PD facilitates Drosophila Dicer-2 cleavage through interactions with the helicase domain and dsRNA.}, author={Kyle D. Trettin and Niladri Kumar Sinha and Debra M. Eckert and Sarah E Apple and B. Bass}, journal={Proceedings of the National Academy of Sciences of the United States of America}, year={2017}, volume={114 38}, pages={E7939-E7948} }