Prachi Agarwala1, Satyaprakash Pandey1, Souvik Maiti2. 1. Proteomics and Structural Biology Unit, CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi 110001, India. 2. Proteomics and Structural Biology Unit, CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi 110001, India; CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India. Electronic address: souvik@igib.res.in.
Abstract
BACKGROUND: Secondary structures in 5' 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' cap of the mRNA and scans along the untranslated region (UTR) before initiating translation, the presence of G-quadruplex in 5' region may have a significant contribution in regulating translation. Here, we investigate the role of G-quadruplex located at the 5' 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 qRT-PCR and dual luciferase assay system. RESULTS: PG4 sequences in 5' UTR of AKT 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' 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' 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' UTR. The neighbouring nucleotide sequence, the intracellular milieu and the interacting partners might render diverse functions to this secondary structure.
BACKGROUND: Secondary structures in 5' 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' cap of the mRNA and scans along the untranslated region (UTR) before initiating translation, the presence of G-quadruplex in 5' region may have a significant contribution in regulating translation. Here, we investigate the role of G-quadruplex located at the 5' 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 qRT-PCR and dual luciferase assay system. RESULTS: PG4 sequences in 5' UTR of AKT 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' 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' 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' UTR. The neighbouring nucleotide sequence, the intracellular milieu and the interacting partners might render diverse functions to this secondary structure.
Authors: Damian S McAninch; Ashley M Heinaman; Cara N Lang; Kathryn R Moss; Gary J Bassell; Mihaela Rita Mihailescu; Timothy L Evans Journal: Mol Biosyst Date: 2017-07-25
Authors: David R Calabrese; Katherine Zlotkowski; Stephanie Alden; William M Hewitt; Colleen M Connelly; Robert M Wilson; Snehal Gaikwad; Lu Chen; Rajarshi Guha; Craig J Thomas; Beverly A Mock; John S Schneekloth Journal: Nucleic Acids Res Date: 2018-04-06 Impact factor: 16.971