Poster abstracts
Poster number 65 submitted by Yow Yong Tan
Investigating the role of the bulge and pentaloop for htrA RNA thermometer melting behavior
Yow Yong Tan (Department of Chemistry and Biochemistry, Denison University), Rachel M. Mitton-Fry (Department of Chemistry and Biochemistry, Denison University)
Abstract:
RNA thermometers (RNATs) are mRNA structures in the 5′-untranslated region of some bacterial heat-shock or pathogenic virulence genes. RNATs regulate the translation of these genes by changing their conformations in response to temperature. In our lab, we study an RNAT in the htrA gene of Salmonella enterica. The htrA RNAT is a 30-nucleotide hairpin structure with a single-nucleotide bulge and a five-nucleotide loop. Our research focuses on investigating the role of these two structural elements for htrA RNAT melting behavior. We synthesized several htrA RNAT sequences with mutations that are specific to these elements. We then performed SHAPE assays on the mutants at 30 and 37 ˚C, temperatures at which the wild type is closed and open, respectively; results suggest that some mutants remain folded at 37 ˚C. Next, we performed additional SHAPE assays over a wide range of temperatures and constructed melting curves for individual nucleotides. The melting curves confirm that these mutants also have slightly elevated melting points, thus implying that the loop and the bulge region are important in fine-tuning the melting temperature of the htrA RNAT to the physiological range.
Keywords: SHAPE, RNAT, htrA