Table of Contents
ISRN Bacteriology
Volume 2013, Article ID 918106, 8 pages
http://dx.doi.org/10.1155/2013/918106
Research Article

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

Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA

Received 4 March 2013; Accepted 31 March 2013

Academic Editors: S. Chatzipanagiotou and A. Grisold

Copyright © 2013 Lorraine T. Stauffer and George V. Stauffer. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The Escherichia coli gcvB gene encodes a small RNA that regulates many genes involved in the transport of dipeptides, oligopeptides, and amino acids (oppA, dppA, cycA, and sstT). A microarray analysis of RNA isolated from an E. coli wild-type and a ΔgcvB strain grown to midlog phase in Luria-Bertani broth indicated that genes not involved in transport are also regulated by GcvB. One gene identified was slp that encodes an outer membrane lipoprotein of unknown function induced when cells enter stationary phase. The aim of this study was to verify that slp is a new target for GcvB-mediated regulation. In this study we used RT-PCR to show that GcvB regulates slp mRNA levels. GcvB negatively controls slp::lacZ in cells grown in Luria-Bertani broth by preventing an Hfq-mediated activation mechanism for slp::lacZ expression. In contrast, in glucose minimal medium supplemented with glycine, GcvB is required for inhibition of slp::lacZ expression, and Hfq prevents GcvB-mediated repression. Thus, GcvB regulates slp in both LB and in glucose minimal + glycine media and likely by mechanisms different than how it regulates sstT, dppA, cycA, and oppA. Repression of slp by GcvB results in an increase in resistance to chloramphenicol, and overexpression of slp in a ΔgcvB strain results in an increase in sensitivity to chloramphenicol.