MicroRNAs (miRNAs) are small, non-coding RNAs that play a key role in regulating gene expression, including RNA silencing and post-transcriptional regulation. In many types of cancers and neurodegenerative diseases, levels of miRNAs have been shown to be severely dysregulated. MiR-615, which typically functions as a tumor suppressor in healthy individuals, is one such example. Cellular levels of this miR-615 are dysregulated in various cancers, such as liver, lung, and breast cancer as well as lymphoma. The premature form of miR-615 contains a guanine-rich region that could form a G-Quadruplex (GQ) structure, potentially inhibiting proper maturation pathways. A GQ is a non-canonical secondary structure which forms within nucleic acids and is stabilized by stacking interactions, Hoogsteen hydrogen bonding, and monovalent cations with an emphasis on potassium. In this study, we characterized the formation of a non-canonical GQ secondary structure within a guanine-rich region of the premature form of miR-615 (pre-miR-615_GQ). We hypothesized that pre-miR-615_GQ folds into a G-quadruplex structure, subsequently leading to inefficient processing of pre-miR-615 and decreased levels of its mature miRNA. This sequence was transcribed <i>in vitro, </i>and various biophysical techniques were utilized, such as CD spectroscopy, UV thermal denaturation, NMR spectroscopy, and gel electrophoresis, to characterize the G-quadruplex secondary structure formation. Here, we demonstrate the formation of a strong GQ secondary structure, especially in the presence of potassium.

Biophysical characterization of the guanine-rich region within pre-microRNA-615

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.