Table of Contents
ISRN Microbiology
Volume 2012 (2012), Article ID 636273, 10 pages
Research Article

The Escherichia coli GcvB sRNA Uses Genetic Redundancy to Control cycA Expression

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

Received 25 February 2012; Accepted 19 March 2012

Academic Editors: H. Asakura, P. D. Ghiringhelli, G. Koraimann, F. Navarro-Garcia, J. Theron, and K. Trulzsch

Copyright © 2012 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.


The Escherichia coli sRNA GcvB regulates several genes involved in transport of amino acids and peptides (sstT, oppA, dppA, and cycA). Two regions of GcvB from nt +124 to +161 and from nt +73 to +82 are complementary with essentially the same region of the cycA mRNA. Transcriptional fusions of cycA to lacZ showed the region of cycA mRNA that can pair with either region of GcvB is necessary for regulation by GcvB. However, mutations in either region of gcvB predicted to disrupt pairing between cycA mRNA and GcvB did not alter expression of a cycA-lacZ translational fusion. A genetic analysis identified nts in GcvB necessary for regulation of the cycA-lacZ fusion. The results show that either region of GcvB complementary to cycA mRNA can basepair with and independently repress cycA-lacZ and both regions need to be changed to cause a significant loss of repression.