Molecular basis of indispensable accuracy of mammalian miRNA biogenesis

David Zapletal; Eliška Táborská; Josef Pasulka; Radek Malı́k; Karel Kubíček; Martina Zanova; Christian Much; Marek Šebesta; Valéria Buccheri; Filip Horvat; Irena Jenickova; Michaela Procházková; Jan Procházka; Matyáš Pinkas; Jiří Nováček; Diego F. Joseph; Radislav Sedláček; Dónal O’Carroll; Richard Štefl; Petr Svoboda

doi:10.1101/2022.04.13.488181

Molecular BiologybioRxivApr 13, 2022

Preprint

Molecular basis of indispensable accuracy of mammalian miRNA biogenesis

David Zapletal, Eliška Táborská iD, Josef Pasulka iD, Radek Malı́k iD, Karel Kubíček iD, Martina Zanova iD, Christian Much iD, Marek Šebesta iD, Valéria Buccheri iD, Filip Horvat iD, Irena Jenickova iD, Michaela Procházková iD, Jan Procházka iD, Matyáš Pinkas iD, Jiří Nováček iD, Diego F. Joseph iD, Radislav Sedláček iD, Dónal O’Carroll iD, Richard Štefl iD, Petr Svoboda iD

Abstract

Mammalian Dicer is the gatekeeper into the essential gene-regulating miRNA pathway. What is committing mammalian Dicer to the miRNA pathway remains unknown. We report that Dicers highly conserved DExD/H helicase domain is the key structural element supporting accurate miRNA biogenesis. While ATPase activity of the domain is non-essential, its loss is lethal in mice. It is required during canonical miRNA biogenesis for efficient recognition, high-fidelity cleavage, and strand selection. Structure of Dicer-miRNA precursor complexes showed that the DExD/H domain acquired helicase-unrelated function defining Dicer conformations, which affect substrate loading and facilitate pre-selection of miRNA precursors. Dicer lacking the DExD/H domain favors conformations enabling reduced substrate selectivity and supporting RNA interference, a different small RNA pathway. Therefore, Dicers DExD/H domain ensures indispensable high-fidelity precursor processing of mammalian miRNAs, which constitutes a structural "mold" for adaptive miRNA evolution.

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