RNA stem-loop to G-quadruplex equilibrium controls mature MicroRNA production inside the cell

TitleRNA stem-loop to G-quadruplex equilibrium controls mature MicroRNA production inside the cell
Publication TypeJournal Article
Year of Publication2015
AuthorsPandey, S, Agarwala, P, Jayaraj, GGunanathan, Gargallo, R, Maiti, S
JournalBiochemistry
Volume54
Issue48
Pagination7067-7078
Date PublishedDEC
ISSN0006-2960
Abstract

The biological role of the existence of overlapping structures in RNA is possible yet remains very unexplored. G-Rich tracts of RNA form G-quadruplexes, while GC-rich sequences prefer stem-loop structures. The equilibrium between alternate structures within RNA may occur and influence its functionality. We tested the equilibrium between G-quadruplex and stem-loop structure in RNA and its effect on biological processes using pre-miRNA as a model system. Dicer enzyme recognizes canonical stem-loop structures in pre-miRNA to produce mature miRNAs. Deviation from stem-loop leads to deregulated mature miRNA levels, providing readout of the existence of an alternate structure per se G-quadruplex-mediated structural interference in miRNA maturation. In vitro analysis using beacon and Dicer cleavage assays indicated that mature miRNA levels depend on relative amounts of K+: and Mg2+ ions, suggesting an ion-dependent structural shift. Further in cellulo studies with and without TmPyP4 (RNA G-quadruplex destabilizer) demonstrated that miRNA biogenesis is modulated by G-quadruplex to stem-loop equilibrium in a subset of pre-miRNAs. Our combined analysis thus provides evidence of the formation of noncanonical G-quaciruplexes in competition with canonical stem-loop structure inside the cell and its effect on miRNA maturation in a comprehensive manner.

DOI10.1021/acs.biochem.5b00574
Type of Journal (Indian or Foreign)

Foreign

Impact Factor (IF)2.876
Divison category: 
Biochemical Sciences