SoxRS-Regulated Expression and Genetic Analysis of theyggXGene ofEscherichia coli
Open Access
- 15 November 2003
- journal article
- Published by American Society for Microbiology in Journal of Bacteriology
- Vol. 185 (22), 6624-6632
- https://doi.org/10.1128/jb.185.22.6624-6632.2003
Abstract
Genomic studies with bacteria have identified redox-responsive genes without known roles in counteracting oxidative damage. Previous transcriptional profiling showed that expression of one such gene, yggX, was activated by superoxide stress in Escherichia coli. Here we show that this activation could be mimicked by artificial expression of the regulatory protein SoxS. Northern analysis confirmed the transcriptional activation of yggX by oxidative stress or SoxS expression but not in response to the related MarA or Rob proteins. Northern analysis showed that mltC, which codes for a peptidoglycan hydrolase and is positioned immediately downstream of yggX, was also regulated by oxidative stress or ectopic expression of SoxS. Purified SoxS protein bound to the predicted yggX promoter region, between positions 223 and 163 upstream from the yggX translational start site. Within this region, a 20-bp sequence was found to be necessary for oxidative stress-mediated activation of yggX transcription. A yggX deletion strain was hypersensitive to the redox-cycling agent paraquat, and a plasmid expressing YggX complemented the sensitivity of the deletion strain. Under exposure to paraquat, the yggX deletion strain showed a deficiency in aconitase activity compared to the isogenic wild-type strain, while expression of YggX from a multicopy plasmid increased the aconitase levels above those of the wild-type strain. These results demonstrate the direct regulation of the yggX gene by the redox-sensing SoxRS system and provide further evidence for the involvement of yggX in protection of iron-sulfur proteins against oxidative damage.Keywords
This publication has 55 references indexed in Scilit:
- The YggX Protein of Salmonella enterica Is Involved in Fe(II) Trafficking and Minimizes the DNA Damage Caused by Hydroxyl RadicalsJournal of Biological Chemistry, 2003
- Contrasting Sensitivities of Escherichia coli Aconitases A and B to Oxidation and Iron DepletionJournal of Bacteriology, 2003
- Genomics of the marA/soxS/rob regulon of Escherichia coli: identification of directly activated promoters by application of molecular genetics and informatics to microarray dataMolecular Microbiology, 2002
- The Complete Genome Sequence of Escherichia coli K-12Science, 1997
- Identification of New Members of the Lytic Transglycosylase Family inHaemophilus influenzaeandEscherichia coliMicrobial Drug Resistance, 1996
- Ambidextrous transcriptional activation by SoxS: requirement for the C‐terminal domain of the RNA polymerase alpha subunit in a subset of Escherichia coli superoxide‐inducible genesMolecular Microbiology, 1996
- Cloning and expression of a murein hydrolase lipoprotein from Escherichia coliMolecular Microbiology, 1995
- Overproduction and Physical Characterization of SoxR, a [2Fe-2S] Protein That Governs an Oxidative Response Regulon in Escherichia coliPublished by Elsevier ,1995
- Two genetically-distinct and differentially-regulated aconitases (AcnA and AcnB) in Escherichia coliMicrobiology, 1994
- Turnover of the Cell Wall Peptidoglycan during Growth of Neisseria gonorrhoeae and Escherichia coli. Relative Stability of Newly Synthesized MaterialMicrobiology, 1985