@article { ISI:000343847000023,
	title = {Role of G-quadruplex located at 5 end of mRNAs},
	journal = {Biochimica Et Biophysica Acta-General Subjects},
	volume = {1840},
	number = {12},
	year = {2014},
	month = {DEC},
	pages = {3503-3510},
	publisher = {ELSEVIER SCIENCE BV},
	address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	abstract = {<p>Background: Secondary structures in 5{\textquoteright} UTR of mRNAs play a critical role in regulating protein synthesis. Though studies have indicated the role of secondary structure G-quadruplex in translational regulation, position-specific effect of G-quadruplex in naturally occurring mRNAs is still not understood. As a pre-initiation complex recognises 5{\textquoteright} cap of the mRNA and scans along the untranslated region (UTR) before initiating translation, the presence of G-quadruplex in 5{\textquoteright} region may have a significant contribution in regulating translation. Here, we investigate the role of G-quadruplex located at the 5{\textquoteright} end of an mRNA. Methods: Biophysical characterisation of putative G-quadruplexes was performed using UV and CD spectroscopy. Functional implication of G-quadruplex in the context of their location was assessed in cellulo using gRT-PCR and dual luciferase assay system. Results: PG4 sequences in 5{\textquoteright} UTR of AICT interacting protein (AKTIP), cathepsin B (CTSB) and forkhead box E3 (FOXE3) mRNAs form G-quadruplex whereas it is unable to form G-quadruplex in apolipoprotein A-I binding protein (APOA1BP). Our results demonstrated diverse roles of G-quadruplex located at 5{\textquoteright} end of mRNAs. Though G-quadruplex in AKTIP and CTSB mRNA act as inhibitory modules, it activates translation in FOXE3 mRNA. Conclusions: Our works suggests that G-quadruplex present at the 5{\textquoteright} terminal of an mRNA behaves differently in a different gene context. It can activate or inhibit gene expression. General significance: This study demonstrated that it is difficult to predict the role of G-quadruplex on the basis of its position in 5{\textquoteright} UTR. The neighbouring nucleotide sequence, the intracellular milieu and the interacting partners might render diverse functions to this secondary structure. (C) 2014 Elsevier B.V. All rights reserved.</p>},
	keywords = {AKTIP, APOA1BP, CTSB, FOXE3, G-quadruplex, UTR},
	issn = {0304-4165},
	doi = {10.1016/j.bbagen.2014.08.017},
	author = {Agarwala, Prachi and Pandey, Satyaprakash and Maiti, Souvik}
}
@article { ISI:000366339300003,
	title = {RNA stem-loop to G-quadruplex equilibrium controls mature MicroRNA production inside the cell},
	journal = {Biochemistry},
	volume = {54},
	number = {48},
	year = {2015},
	month = {DEC},
	pages = {7067-7078},
	publisher = {AMER CHEMICAL SOC},
	address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA},
	abstract = {<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>},
	issn = {0006-2960},
	doi = {10.1021/acs.biochem.5b00574},
	author = {Pandey, Satyaprakash and Agarwala, Prachi and Jayaraj, Gopal Gunanathan and Gargallo, Raimundo and Maiti, Souvik}
}
