TRBP ensures efficient Dicer processing of precursor microRNA in RNA-crowded environments
Mohamed Fareh (TU Delft - Applied Sciences, Kavli institute of nanoscience Delft)
Kyu Hyeon Yeom (TU Delft - Applied Sciences, Kavli institute of nanoscience Delft)
A.C. van Eijkeren-Haagsma (Kavli institute of nanoscience Delft, TU Delft - BN/Technici en Analisten)
Sweeny Chauhan (TU Delft - Applied Sciences, Kavli institute of nanoscience Delft)
Inha Heo (Kavli institute of nanoscience Delft, TU Delft - Applied Sciences)
Chirlmin Joo (Kavli institute of nanoscience Delft, TU Delft - Applied Sciences)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
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.