Poster abstracts
Poster number 50 submitted by Md Ismail Hossain
RNA Thermometer Thermal Stability Modulated by pH-Sensitive Molecular Switching
Md Ismail Hossain (Department and institution: Department of Chemistry & Biochemistry, Ohio University, Athens, OH), Erin R. Murphy (Department and institution: Department of Biomedical Sciences, Ohio University Athens, OH), Jennifer V. Hines (Department and institution: Department of Chemistry & Biochemistry, Ohio University, Athens, OH)
Abstract:
Bacterial resistance to current medicines continues to be a significant global health threat. Consequently, there is a need to develop new therapeutic approaches that prevent or overcome bacterial infections. One emerging area of investigation is targeting regulatory RNA, which mediates gene expression in bacteria. In order for drug discovery studies to be successful, a detailed understanding of the molecular mechanism of the RNA-mediated regulation is needed. In this study, we investigated the effect of pH on the thermal stability of a set of RNA thermometers (RNATs) found in the untranslated leader region of Shigella shuA, shuT, and ompA mRNA. 1,2 Shu (Shigella heme utilization) proteins have essential roles in utilizing heme as a sole source of iron. Outer membrane protein A (ompA) is a virulence factor required for the cell adhesion, biofilm formation, invasion, and spread of the bacteria. UV monitored thermal denaturation was used to determine the melting temperature (Tm) and thermodynamic parameters for model RNAs of each RNAT. At low ionic strength, the Tm of the shuT and ompA RNA thermometers were pH dependent. However, at high ionic strength, only the Tm of shuT was pH dependent. The Tm of shuA was not pH-dependent at either low and high ionic strength, but it was significantly higher than that of shuT and ompA. We also investigated the effect of pH on RNAT binding of a 16S rRNA mimic using a fluorophore-quencher labeled model RNA. For ompA, the EC50 for binding the 16S rRNA mimic was pH dependent. These results indicate that in some RNA thermometers, pH-sensitive molecular switching may play a role in modulating gene expression regulation.
References:
1. Kouse, Andrew B., Francesco Righetti, Jens Kortmann, Franz Narberhaus, and Erin R. Murphy. "RNA-mediated thermoregulation of iron-acquisition genes in Shigella dysenteriae and pathogenic Escherichia coli." PloS one 8, no. 5 (2013): e63781.
2. Murphy, Erin R., Johanna Roßmanith, Jacob Sieg, Megan E. Fris, Hebaallaha Hussein, Andrew B. Kouse, Kevin Gross et al. "Regulation of OmpA translation and Shigella dysenteriae virulence by an RNA thermometer." Infection and immunity 88, no. 3 (2020): e00871-19.
Keywords: RNA Thermometer, shuT, shuA, OmpA, Molecular switching