title: TRBP ensures efficient Dicer processing of precursor microRNA in RNA-crowded environments.
abstract: The RNA-binding protein TRBP is a central component of the Dicer complex. Despite a decade of biochemical and structural studies, the essential functionality of TRBP in microRNA (miRNA) biogenesis remains unknown. Here we show that TRBP is an integral cofactor for time-efficient Dicer processing in RNA-crowded environments. We competed for Dicer processing of pre-miRNA with a large amount of cellular RNA species and found that Dicer-TRBP, but not Dicer alone, remains resilient. To apprehend the mechanism of this substrate selectivity, we use single-molecule fluorescence. The real-time observation reveals that TRBP acts as a gatekeeper, precluding Dicer from engaging with pre-miRNA-like substrates. TRBP acquires the selectivity using the PAZ domain of Dicer, whereas Dicer moderates the RNA-binding affinity of TRBP for fast turnover. This coordinated action between TRBP and Dicer accomplishes an efficient way of discarding pre-miRNA-like substrates.
authors.affiliation: Kavli Institute of NanoScience, Delft University of Technology, 2629HZ Delft, The Netherlands.|Department of BioNanoScience, Delft University of Technology, 2629HZ Delft, The Netherlands.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Fareh
authors.affiliation: Kavli Institute of NanoScience, Delft University of Technology, 2629HZ Delft, The Netherlands.|Department of BioNanoScience, Delft University of Technology, 2629HZ Delft, The Netherlands.
authors.forename: Kyu-Hyeon
authors.initials: KH
authors.lastname: Yeom
authors.affiliation: Kavli Institute of NanoScience, Delft University of Technology, 2629HZ Delft, The Netherlands.|Department of BioNanoScience, Delft University of Technology, 2629HZ Delft, The Netherlands.
authors.forename: Anna C
authors.initials: AC
authors.lastname: Haagsma
authors.affiliation: Kavli Institute of NanoScience, Delft University of Technology, 2629HZ Delft, The Netherlands.|Department of BioNanoScience, Delft University of Technology, 2629HZ Delft, The Netherlands.
authors.forename: Sweeny
authors.initials: S
authors.lastname: Chauhan
authors.affiliation: Kavli Institute of NanoScience, Delft University of Technology, 2629HZ Delft, The Netherlands.|Department of BioNanoScience, Delft University of Technology, 2629HZ Delft, The Netherlands.
authors.forename: Inha
authors.initials: I
authors.lastname: Heo
authors.affiliation: Kavli Institute of NanoScience, Delft University of Technology, 2629HZ Delft, The Netherlands.|Department of BioNanoScience, Delft University of Technology, 2629HZ Delft, The Netherlands.
authors.forename: Chirlmin
authors.identifier: 0000-0003-2803-0335
authors.initials: C
authors.lastname: Joo
mesh_terms: D057809:HEK293 Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D035683:MicroRNAs / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000378:metabolism; D056918:Nuclear Receptor Coactivators; D011485:Protein Binding; D000072417:Protein Domains; D012313:RNA; D012322:RNA Precursors / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional / Q000502:physiology*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D043244:Ribonuclease III / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D035683:MicroRNAs; D046912:Multiprotein Complexes; D056918:Nuclear Receptor Coactivators; D012322:RNA Precursors; D016601:RNA-Binding Proteins; D012313:RNA; D043244:Ribonuclease III