Multiple Roles for the sRNA GcvB in the Regulation of Slp Levels inEscherichia coli

This is the authors' abstract. We don't add key points for this paper.

TheEscherichia coli gcvBgene encodes a small RNA that regulates many genes involved in the transport of dipeptides, oligopeptides, and amino acids (oppA,dppA,cycA, andsstT). A microarray analysis of RNA isolated from anE. coliwild-type and aΔgcvBstrain grown to midlog phase in Luria-Bertani broth indicated that genes not involved in transport are also regulated by GcvB. One gene identified wasslpthat encodes an outer membrane lipoprotein of unknown function induced when cells enter stationary phase. The aim of this study was to verify thatslpis a new target for GcvB-mediated regulation. In this study we used RT-PCR to show that GcvB regulatesslpmRNA levels. GcvB negatively controlsslp::lacZin cells grown in Luria-Bertani broth by preventing an Hfq-mediated activation mechanism forslp::lacZexpression. In contrast, in glucose minimal medium supplemented with glycine, GcvB is required for inhibition ofslp::lacZexpression, and Hfq prevents GcvB-mediated repression. Thus, GcvB regulatesslpin both LB and in glucose minimal + glycine media and likely by mechanisms different than how it regulatessstT,dppA,cycA,andoppA. Repression ofslpby GcvB results in an increase in resistance to chloramphenicol, and overexpression ofslpin aΔgcvBstrain results in an increase in sensitivity to chloramphenicol.