title: Structural and functional insights into the fly microRNA biogenesis factor Loquacious.
abstract: In the microRNA (miRNA) pathway, Dicer processes precursors to mature miRNAs. For efficient processing, double-stranded RNA-binding proteins support Dicer proteins. In flies, Loquacious (Loqs) interacts with Dicer1 (dmDcr1) to facilitate miRNA processing. Here, we have solved the structure of the third double-stranded RNA-binding domain (dsRBD) of Loqs and define specific structural elements that interact with dmDcr1. In addition, we show that the linker preceding dsRBD3 contributes significantly to dmDcr1 binding. Furthermore, our structural work demonstrates that the third dsRBD of Loqs forms homodimers. Mutations in the dimerization interface abrogate dmDcr1 interaction. Loqs, however, binds to dmDcr1 as a monomer using the identified dimerization surface, which suggests that Loqs might form dimers under conditions where dmDcr1 is absent or not accessible. Since critical sequence elements are conserved, we suggest that dimerization might be a general feature of dsRBD proteins in gene silencing.
authors.affiliation: Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany.
authors.forename: Leonhard
authors.initials: L
authors.lastname: Jakob
authors.affiliation: Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Treiber
authors.affiliation: Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany.
authors.forename: Nora
authors.initials: N
authors.lastname: Treiber
authors.affiliation: Department of Microbiology and Archaea Centre, Laboratory of Single-Molecule Biochemistry, University of Regensburg, 93053 Regensburg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Gust
authors.affiliation: Department of Microbiology and Archaea Centre, Laboratory of Single-Molecule Biochemistry, University of Regensburg, 93053 Regensburg, Germany.
authors.forename: Kevin
authors.initials: K
authors.lastname: Kramm
authors.affiliation: Intana Bioscience GmbH, 82152 Planegg, Martinsried, Germany.
authors.forename: Kerrin
authors.initials: K
authors.lastname: Hansen
authors.affiliation: Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Stotz
authors.affiliation: Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany.
authors.forename: Ludwig
authors.initials: L
authors.lastname: Wankerl
authors.affiliation: Gene Center and Department of Biochemistry, Ludwig-Maximilians-University, 81377 München, Germany.
authors.forename: Franz
authors.initials: F
authors.lastname: Herzog
authors.affiliation: Intana Bioscience GmbH, 82152 Planegg, Martinsried, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Hannus
authors.affiliation: Department of Microbiology and Archaea Centre, Laboratory of Single-Molecule Biochemistry, University of Regensburg, 93053 Regensburg, Germany.
authors.forename: Dina
authors.initials: D
authors.lastname: Grohmann
authors.affiliation: Biochemistry Center Regensburg (BZR), Laboratory for RNA Biology, University of Regensburg, 93053 Regensburg, Germany.
authors.forename: Gunter
authors.initials: G
authors.lastname: Meister
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018360:Crystallography, X-Ray; D019281:Dimerization; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics*; D020868:Gene Silencing; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D011485:Protein Binding; D011487:Protein Conformation; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D013050:Spectrometry, Fluorescence
chemical_list: D029721:Drosophila Proteins; C503213:Loqs protein, Drosophila; D035683:MicroRNAs; D016601:RNA-Binding Proteins
keywords: Dicer; Drosophila; Loquacious; dsRBD; fluorescence spectroscopy; gene silencing; microRNA