Studying the Effect of RNA G-quadruplex Structure on Precursor MicroRNA Processing and Post-transcriptional Regulation

Description

The structure of nucleic acids often governs the biological function of many cellularprocesses. Guanine-rich sequences in nucleic acids can fold into intricate structuralmotifs known as G-quadruplexes, and they are of special interest due to their peculiarstructural scaffolds and potential associations with gene regulatory features and humandiseases. A number of reports have suggested that G-quadruplexes can regulate geneexpression and cellular processes, ranged from replication, transcription, RNA processingto translation. Recently, DNA and RNA G-quadruplexes have been detected in humancells and tissues using G-quadruplex-specific antibody, providing substantial evidencefor the existence of G-quadruplexes in humans. Bioinformatics-based searching andexperimental-based sequencing profiling in human genome and transcriptome reportedmore than thousands of G-quadruplexes, in which a few of the specific examples havebeen verified to possess gene regulatory roles, offering a glimpse of the overall potentialof G-quadruplexes functions in living cells.Compared with its DNA counterparts, current understanding of RNA G-quadruplexes isstill rudimentary and the biological consequences of myriad RNA G-quadruplexesformation remain elusive, making establishment of G-quadruplex structure-functionrelationship particularly challenging. Our recent computational search among the humanprecursor microRNAs has predicted almost a hundred of putative RNA G-quadruplexes,and we have demonstrated in selected example that the formation of RNA G-quadruplexin precursor microRNA affect the Dicer processing and mature microRNAmaturation. Driven by these initial findings, Our central hypothesis of this proposal isthat RNA G-quadruplex structures are stable in the human precursor microRNAs,generally affects Dicer processing, and can function as a regulatory element to affectgene expression in living cells. To directly test this hypothesis, we propose to employchemical and biochemical experimental approaches to address three central questions:A) Are RNA G-quadruplexes forming in precursor microRNA hairpin?B) Does the formation of RNA G-quadruplex in precursor microRNA affect Dicerprocessing and reporter gene expression?C) Does the formation of G-quadruplex in precursor microRNA control the nativeprotein expression of targeted mRNAs?The proposal presented here is timely, original, and inter-disciplinary that integrateschemical biology, structural biology, and molecular biology. Successful execution of thisproposal will provide us profound insights into the role of RNA G-quadruplex structuresin non-coding RNAs on post-transcriptional regulation. Our group is one of few labsthat have the necessary expertise and facilities to carry out this proposal, thus we areconfident that the proposed research project will be accomplished in time if funded.?