02126nas a2200193   4500008004100000022001400041245009800055210006900153260007100222300001400293490000700307520137200314100002501686700002101711700003101732700002301763700001801786856012801804       2015                        eng d  a0006-296000aRNA stem-loop to G-quadruplex equilibrium controls mature MicroRNA production inside the cell0 aRNA stemloop to Gquadruplex equilibrium controls mature MicroRNA  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcDEC  a7067-70780 v543 a<p>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.</p>1 aPandey, Satyaprakash1 aAgarwala, Prachi1 aJayaraj, Gopal, Gunanathan1 aGargallo, Raimundo1 aMaiti, Souvik  uhttps://library.ncl.res.in/content/rna-stem-loop-g-quadruplex-equilibrium-controls-mature-microrna-production-inside-cell-0