Talk Abstracts

Talk on Friday 02:30-02:45pm submitted by Elizabeth Jolley

Temperature-sensitive RNAs: flanking sequence of a known RNA thermometer (RNAT) and identification of novel RNATs genome-wide

Elizabeth A. Jolley (Department of Chemistry, Pennsylvania State University), Kathryn M. Bormes (Department of Chemistry, Pennsylvania State University, current affiliation Sidney Kimmel Medical College, Thomas Jefferson University), Helen Yahknin (Department of Biology and Molecular Biology, Pennsylvania State University), David C. Tack, Paul Babitzke (Department of Biology and Molecular Biology, Pennsylvania State University), Philip C. Bevilacqua (Department of Chemistry, Pennsylvania State University)

Abstract:
RNA structure is known to regulate bacterial gene expression by several distinct mechanisms. These riboregulators respond to a variety of environmental and cellular stimuli, one of which is temperature. RNA elements that change structure with temperature are termed RNA thermometers (RNATs). We conducted two studies on the effects of heat on bacterial RNAs: one on elements upstream of an RNAT and one on genome-wide effects of heat on RNA folding. Often found upstream of heat shock protein coding sequences, RNATs have a thermolabile RNA hairpin that sequesters the Shine-Dalgarno (SD) sequence and sometimes have additional hairpins in the sequence further upstream. While many RNATs have been studied to confirm that they exist or to determine their function, few studies have examined the role that upstream hairpins may play. We examined this often-overlooked region and determined that the upstream hairpins likely act as folding guides for the final RNAT structure.¹

During a heat shock, cells utilize heat shock proteins to acclimate to this new environmental condition. However, there could be other genes that make use of similar temperature-response mechanisms to adjust to growth at different temperatures. We conducted a genome-wide study of RNA structure in Bacillus subtilis at four temperatures (23°C, 30°C, 37°C, 42°C). This study revealed many RNAs with significant reactivity changes with increasing temperature. Two of these RNAs, glpF (glycerol permease) and glpT (glycerol-3-phosphate permease), were found to increase expression in an RNAT-controlled manner.² Together, these studies^1,2 exemplify the many structural changes that RNA undergoes to alter cellular physiology in response to changing environmental conditions.

References:
¹Jolley, EA; Bormes, KA; Bevilacqua, PC. (2022) J. Mol. Biol., in press
²Jolley, EA; Yahknin, H; Tack, DC; Babitzke, P; Bevilacqua, PC. In preparation

Keywords: flanking sequence, RNAT, In vivo probing