Present address: Faculty of Applied Sciences, University of Sunderland, Sunderland SR1 3SD, UK.
Organization of the LEE1 operon regulatory region of enterohaemorrhagic Escherichia coli O157:H7 and activation by GrlA
Article first published online: 21 NOV 2010
© 2010 Blackwell Publishing Ltd
Volume 79, Issue 2, pages 468–483, January 2011
How to Cite
Islam, Md. S., Bingle, L. E. H., Pallen, M. J. and Busby, S. J. W. (2011), Organization of the LEE1 operon regulatory region of enterohaemorrhagic Escherichia coli O157:H7 and activation by GrlA. Molecular Microbiology, 79: 468–483. doi: 10.1111/j.1365-2958.2010.07460.x
- Issue published online: 11 JAN 2011
- Article first published online: 21 NOV 2010
- Accepted 6 November, 2010.
Expression of the genes in the locus of enterocyte effacement (LEE) in enterohaemorrhagic Escherichia coli is primarily co-ordinated by expression of the LEE1 operon. GrlA is a LEE-encoded transcription regulator that has been proposed to be involved in the regulation of expression of the LEE1 operon. We describe a simple plasmid-based system to investigate the LEE1 operon regulatory region and to study GrlA-dependent effects. We report that GrlA can activate transcription initiation at the LEE1 P1 promoter by binding to a target located within the 18-base-pair spacer between the promoter −10 and −35 elements, which were defined by mutational analysis. Shortening this spacer to 17 base pairs increases P1 promoter activity and short-circuits GrlA-dependent activation. Hence, at the P1 promoter, the action of GrlA resembles that of many MerR family transcription activators at their target promoters.