title: The Drosophila Dicer-1 Partner Loquacious Enhances miRNA Processing from Hairpins with Unstable Structures at the Dicing Site.
abstract: In Drosophila, Dicer-1 binds Loquacious-PB (Loqs-PB) as its major co-factor. Previous analyses indicated that loqs mutants only partially impede miRNA processing, but the activity of minor isoforms or maternally deposited Loqs was not eliminated in these studies. We addressed this by generating a cell line from loqs-null embryos and found that only ∼40% of miRNAs showed clear Loqs dependence. Genome-wide comparison of the hairpin structure and Loqs dependence suggested that Loqs substrates are influenced by base-pairing status at the dicing site. Artificial alteration of base-pairing stability at this position in model miRNA hairpins resulted in predicted changes in Loqs dependence, providing evidence for this hypothesis. Finally, we found that evolutionarily young miRNA genes tended to be Loqs dependent. We propose that Loqs may have roles in assisting the de novo emergence of miRNA genes by facilitating dicing of suboptimal hairpin substrates.
authors.affiliation: Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore; School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 639798, Singapore.
authors.forename: Mandy Yu Theng
authors.initials: MY
authors.lastname: Lim
authors.affiliation: Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543, Singapore.
authors.forename: Alvin Wei Tian
authors.initials: AW
authors.lastname: Ng
authors.affiliation: Sloan-Kettering Institute, Department of Developmental Biology, New York, NY 10065, USA.
authors.forename: Yuting
authors.initials: Y
authors.lastname: Chou
authors.affiliation: Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543, Singapore.
authors.forename: Teck Por
authors.initials: TP
authors.lastname: Lim
authors.affiliation: Department of Molecular Genetics, Ohio State University, Columbus, OH 43210, USA.
authors.forename: Amanda
authors.initials: A
authors.lastname: Simcox
authors.affiliation: Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543, Singapore; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.
authors.forename: Greg
authors.initials: G
authors.lastname: Tucker-Kellogg
authors.affiliation: Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore; School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 639798, Singapore. Electronic address: okamurak@tll.org.sg.
authors.forename: Katsutomo
authors.initials: K
authors.lastname: Okamura
mesh_terms: D000818:Animals; D020029:Base Pairing / Q000235:genetics; D001483:Base Sequence; D002460:Cell Line; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics*; D019143:Evolution, Molecular; D055786:Gene Knockout Techniques; D015723:Gene Library; D035683:MicroRNAs / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009690:Nucleic Acid Conformation; D010641:Phenotype; D020365:RNA Helicases / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional / Q000235:genetics*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D015203:Reproducibility of Results; D043244:Ribonuclease III / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; C503213:Loqs protein, Drosophila; D035683:MicroRNAs; D016601:RNA-Binding Proteins; C515033:Dcr-1 protein, Drosophila; D043244:Ribonuclease III; D020365:RNA Helicases