Abstract
The precise regulation of microRNA (miRNA) biogenesis seems to be critically important for the proper functioning of all eukaryotic organisms. Even small changes in the levels of specific miRNAs can initiate pathological processes, including carcinogenesis. Accordingly, there is a great need to develop effective methods for the regulation of miRNA biogenesis and activity. In this study, we focused on the final step of miRNA biogenesis; i.e., miRNA processing by Dicer. To test our hypothesis that RNA molecules can function not only as Dicer substrates but also as Dicer regulators, we previously identified by SELEX a pool of RNA oligomers that bind to human Dicer. We found that certain of these RNA oligomers could selectively inhibit the formation of specific miRNAs. Here, we show that these specific inhibitors can simultaneously bind both Dicer and pre-miRNAs. These bifunctional riboregulators interfere with miRNA maturation by affecting pre-miRNA structure and sequestering Dicer. Based on these observations, we designed a set of short oligomers (12 nucleotides long) that were capable of influencing pre-miRNA processing in vitro, both in reactions involving recombinant human Dicer and in cytosolic extracts. We propose that the same strategy may be used to develop effective and selective regulators to control the production of any miRNA. Overall, our findings indicate that the interactions between pre-miRNAs and other RNAs may form very complex regulatory networks that modulate miRNA biogenesis and consequently gene expression.
Highlights
It has become increasingly clear that the majority of human protein-coding genes are regulated by microRNAs [1,2]
Selective Inhibition of miRNA Processing by hdicer Previously, we showed that RNA oligomers can bind to human Dicer (hDicer) and regulate its activity
In a pool of hDicer-binding RNA oligomers identified by SELEX, we found molecules that inhibited premiRNA processing by acting as: (i) competitive inhibitors – these oligomers were cut by hDicer; and (ii) allosteric inhibitors – these molecules were not digested by hDicer [32]
Summary
It has become increasingly clear that the majority of human protein-coding genes are regulated by microRNAs (miRNAs) [1,2]. It means that miRNAs are involved in many biological processes, including developmental timing, growth, differentiation and apoptosis [3,4,5]. The ribonuclease Dicer is one of the key enzymes involved in the biogenesis of miRNAs in humans. This enzyme excises mature, functional miRNAs from 50–70 nt stem-loop precursors called pre-miRNAs [13].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
