title: Processing of pre-microRNAs by the Dicer-1-Loquacious complex in Drosophila cells.
abstract: microRNAs (miRNAs) are a large family of 21- to 22-nucleotide non-coding RNAs that interact with target mRNAs at specific sites to induce cleavage of the message or inhibit translation. miRNAs are excised in a stepwise process from primary miRNA (pri-miRNA) transcripts. The Drosha-Pasha/DGCR8 complex in the nucleus cleaves pri-miRNAs to release hairpin-shaped precursor miRNAs (pre-miRNAs). These pre-miRNAs are then exported to the cytoplasm and further processed by Dicer to mature miRNAs. Here we show that Drosophila Dicer-1 interacts with Loquacious, a double-stranded RNA-binding domain protein. Depletion of Loquacious results in pre-miRNA accumulation in Drosophila S2 cells, as is the case for depletion of Dicer-1. Immuno-affinity purification experiments revealed that along with Dicer-1, Loquacious resides in a functional pre-miRNA processing complex, and stimulates and directs the specific pre-miRNA processing activity. These results support a model in which Loquacious mediates miRNA biogenesis and, thereby, the expression of genes regulated by miRNAs.
authors.affiliation: Institute for Genome Research, University of Tokushima, Kuramoto, Tokushima, Japan.
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Saito
authors.forename: Akira
authors.initials: A
authors.lastname: Ishizuka
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Siomi
authors.forename: Mikiko C
authors.initials: MC
authors.lastname: Siomi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000378:metabolism*; D035683:MicroRNAs / Q000378:metabolism*; D008969:Molecular Sequence Data; D025941:Protein Interaction Mapping; D016601:RNA-Binding Proteins / Q000378:metabolism*; D043244:Ribonuclease III / Q000378:metabolism*; D016415:Sequence Alignment
chemical_list: D029721:Drosophila Proteins; C503213:Loqs protein, Drosophila; D035683:MicroRNAs; D016601:RNA-Binding Proteins; D043244:Ribonuclease III