Impact of RNA modification and UVR exposure on gene expression.

Abstract

By Kyle Necamp, Chemistry; Katina Pahoundis, Biochemistry

Advisor: Bala Addepalli

Presentation ID: PM_D12

Abstract: RNA modifications play multiple roles in maintaining structure and function of transfer RNAs during cellular gene expression (1). Ultraviolet radiation is a known genotoxic agent and degrades post-transcriptional modifications found at the anticodon region of tRNA. Our previous studies (2) indicated that the absence of a nucleoside modification, mnm5s2U (5-methylaminomethyl-2-thiouridine) makes Escherichia coli more susceptible to UVR damage than the wild type cells under identical exposure conditions. This modification was enzymatically made by two genes, MnmC (methyl transferase) and MnmA (2-thiouridylase). The goal of current investigation is to understand the impact of ultraviolet radiation (UVR) exposure in combination with mnm5s2U deficiency on gene expression using Renilla luciferase as a reporter system. Preliminary studies indicate reduced activity of luciferase in the mnmA cell line compared to wild type K-12 cells under identical conditions of exposure. Complementation studies with MnmA expressed through a plasmid in the mnmA mutant indicated restoration of Renilla luciferase enzyme activity and wild-type behavior. Further studies are in progress to investigate the type of changes inflicted on Renilla luciferase upon UVR exposure in the absence of mnm5s2U. Key words: RNA modifications, mnm5s2U, UVR, E.coli References 1. Song, J. and C. Yi (2017). "Chemical Modifications to RNA: A New Layer of Gene Expression Regulation." ACS Chem Biol 12(2): 316-325. 2. Sun C, Jora M, Solivio B, Limbach PA, Addepalli B. (2018) The Effects of Ultraviolet Radiation on Nucleoside Modifications in RNA. ACS Chem Biol. 13(3):567-572.