Poster abstracts

Poster number 59 submitted by Ambar Rana

Investigation of the expression of the ykkCD multidrug-resistant efflux pump in response to antibiotics

Ambar Rana (Department of Chemistry Ball State University), John McKillip (Department of Biology Ball State University), Timea Gerczei (Department of Chemistry Ball State University)

Abstract:
Riboswitches are highly structured mRNA elements that specifically bind to small metabolites to regulate gene expression in a cis-fashion. Research in our lab focuses on testing whether the ykkCD putative riboswitch acts as a toxin sensor to trigger expression of a multidrug resistance efflux pump (also called ykkCD) in response to toxic compounds. Efflux pumps are membrane transporters involved in the extrusion of toxic substrates from the cells into the external environment thereby playing an important role in bacterial defense against antibiotics. In this work we tested whether expression of the ykkCD efflux pump is up-regulated or down-regulated in response to toxic compounds. We used the Gramm-positive model organism Bacillus Subtilis for our studies. Cells were grown in the presence of various antibiotics and ykkCD efflux pump mRNA levels were detected using Nucleic Acid Sequence Based Amplification (NASBA). NASBA is a very sensitive technique and ideal to detect small changes in mRNA levels. Our work shows that expression of the ykkCD multidrug-resistance efflux pump is upregulated in tetracyclin but not in streptomycin or chloramphenicol treated cells. Since bacterial strains are showing increased resistance to various drugs it is very important to uncover how bacterial defense is triggered in response to antibiotics. We posit that the ykkCD putative riboswitch could serve as a target in the fight against bacterial pathogens.

Keywords: riboswitch, gene expression regulation, qPCR