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Translation Modulation of Cellular mRNA by G-Quadruplex Structures

Bhattacharyya, Debmalya
http://orcid.org/0000-0002-0434-7541
http://rave.ohiolink.edu/etdc/view?acc_num=kent1469636863

Abstract Details

2016, PHD, Kent State University, College of Arts and Sciences / Department of Chemistry.
Guanine-rich nucleic acid sequences adopt a four stranded secondary structure referred to as a G-quadruplex (GQ). These structures, when adopted by RNA sequences, have been shown to modulate several biochemical processes, especially translation. The RNA GQ structures are widely perceived as translation repressors although a few recent reports suggest that they are sometimes essential for translation. The presence of GQ structures in IRES elements was known to be essential for cap-independent translation initiation. We investigated the mechanism of how these structures aid IRES-mediated translation initiation wherein we observed that an independently folding RNA GQ domain in the internal ribosome entry site (IRES) of human VEGF mRNA directly recruits the 40S ribosomal subunit thereby controlling non-canonical translation initiation. These findings provide a unique and defined role of an RNA structure in the cap-independent translation initiation by cellular IRESs explaining a hitherto unknown mechanism for the necessity of a GQ structure in IRES function. Furthermore, we employed RNA engineering to demonstrate that RNA GQ function is dependent on the context in which such domains are located. Additionally, we also report a strategy for harnessing the natural ability of RNA GQs to inhibit translation by rationally inducing RNA: DNA hybrid GQ on a targeted mRNA to knockdown endogenous gene expression. Targeted RNA: DNA hybrid GQ structures were induced at the 5'-untranslated region (UTR) and the protein coding region of the eIF-4E mRNA by partially modified extraneous DNA sequences. We observed the formation of a stable induced GQ in vitro at a physiologically relevant salt concentration. The rationally designed GQ inducing sequences resulted in anti-proliferation of HeLa cells in a dose-dependent manner. Also, inducing GQ in the 5'-UTR and the protein-coding region of eIF-4E mRNA in HeLa cells resulted in a 30% and 60% inhibition of the endogenous protein expression respectively. The above strategy opens up a new avenue of anti-cancer RNA therapeutics.
Soumitra Basu, Ph.D (Advisor)
William C. Merrick, Ph.D (Committee Member)
Paul Sampson, Ph.D (Committee Member)
Roger Gregory, Ph.D (Committee Member)
Gail Fraizer, Ph.D (Committee Member)
160 p.
Biochemistry; Biomedical Research; Cellular Biology; Molecular Biology
G-quadruplex, mRNA, translation, hVEGF, structure-function relation, IRES, eIF-4E, targeted knockdown, nucleic acid therapeutics,

Recommended Citations

Citations

  • Bhattacharyya, D. (2016). Translation Modulation of Cellular mRNA by G-Quadruplex Structures [Doctoral dissertation, Kent State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=kent1469636863

    APA Style (7th edition)

  • Bhattacharyya, Debmalya. Translation Modulation of Cellular mRNA by G-Quadruplex Structures. 2016. Kent State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=kent1469636863.

    MLA Style (8th edition)

  • Bhattacharyya, Debmalya. "Translation Modulation of Cellular mRNA by G-Quadruplex Structures." Doctoral dissertation, Kent State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=kent1469636863

    Chicago Manual of Style (17th edition)

kent1469636863
360
© 2016, some rights reserved.Creative Commons License Translation Modulation of Cellular mRNA by G-Quadruplex Structures by Debmalya Bhattacharyya is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by Kent State University and OhioLINK.