Poster abstracts

Poster number 23 submitted by Alysa Frank

How expression of antibiotic resistance genes is triggered in bacteria: a structural study of the ykkCD tetracycline-responsive riboswitch RNA

Alysa M. Frank (Ball State University), Krystal Roark (Ball State University), Timea Gerczei (Ball State University)

Abstract:
Riboswitches are RNA aptamers that bind to small molecules thus causing allosteric structural changes and regulating gene expression. Most identified riboswitches specifically recognize the metabolic product of the gene to be regulated. Once metabolite concentrations reach a threshold it will bind to the riboswitch causing a structural change. In most cases this binding will turn off transcription or translation of the metabolite-producing gene. The ykkCD riboswitch appears to recognize the antibiotic tetracycline and up-regulates expression of an efflux pump that exports toxic drugs from the bacterial cell. The heart of riboswitch function is allosteric structural change triggered by metabolite binding. In this work we present nucleic acid footprinting studies in order to (1) map where tetracycline is binding to the RNA; (2) compare these findings with mutagensis studies performed by pervious members of the lab. Once these data have been collected we then want to map the structural change that take place upon binding antibiotic tetracycline to determine whether gene expression is regulated at the transcription or translation stage. Taken together these data provide insight into how expression of antibiotic resistant genes are triggered - a key step in fighting bacterial pathogens.

Keywords: regulation, footprinting, gene expression