Journal article
The Bacillus subtilis Extracytoplasmic Function σ Factor σ V Is Induced by Lysozyme and Provides Resistance to Lysozyme
Journal of bacteriology, Vol.193(22), pp.6215-6222
11/15/2011
DOI: 10.1128/JB.05467-11
PMCID: PMC3209206
PMID: 21856855
Abstract
ABSTRACT Bacteria encounter numerous environmental stresses which can delay or inhibit their growth. Many bacteria utilize alternative σ factors to regulate subsets of genes required to overcome different extracellular assaults. The largest group of these alternative σ factors are the extracytoplasmic function (ECF) σ factors. In this paper, we demonstrate that the expression of the ECF σ factor σ V in Bacillus subtilis is induced specifically by lysozyme but not other cell wall-damaging agents. A mutation in sigV results in increased sensitivity to lysozyme killing, suggesting that σ V is required for lysozyme resistance. Using reverse transcription (RT)-PCR, we show that the previously uncharacterized gene yrhL (here referred to as oatA for O -acetyltransferase) is in a four-gene operon which includes sigV and rsiV . In quantitative RT-PCR experiments, the expression of oatA is induced by lysozyme stress. Lysozyme induction of oatA is dependent upon σ V . Overexpression of oatA in a sigV mutant restores lysozyme resistance to wild-type levels. This suggests that OatA is required for σ V -dependent resistance to lysozyme. We also tested the ability of lysozyme to induce the other ECF σ factors and found that only the expression of sigV is lysozyme inducible. However, we found that the other ECF σ factors contributed to lysozyme resistance. We found that sigX and sigM mutations alone had very little effect on lysozyme resistance but when combined with a sigV mutation resulted in significantly greater lysozyme sensitivity than the sigV mutation alone. This suggests that sigV , sigX , and sigM may act synergistically to control lysozyme resistance. In addition, we show that two ECF σ factor-regulated genes, dltA and pbpX , are required for lysozyme resistance. Thus, we have identified three independent mechanisms which B. subtilis utilizes to avoid killing by lysozyme.
Details
- Title: Subtitle
- The Bacillus subtilis Extracytoplasmic Function σ Factor σ V Is Induced by Lysozyme and Provides Resistance to Lysozyme
- Creators
- Theresa D Ho - Department of Microbiology, Carver College of Medicine, University of Iowa, 51 Newton Rd., Iowa City, Iowa 52242Jessica L Hastie - Department of Microbiology, Carver College of Medicine, University of Iowa, 51 Newton Rd., Iowa City, Iowa 52242Peter J Intile - Department of Microbiology, Carver College of Medicine, University of Iowa, 51 Newton Rd., Iowa City, Iowa 52242Craig D Ellermeier - Department of Microbiology, Carver College of Medicine, University of Iowa, 51 Newton Rd., Iowa City, Iowa 52242
- Resource Type
- Journal article
- Publication Details
- Journal of bacteriology, Vol.193(22), pp.6215-6222
- DOI
- 10.1128/JB.05467-11
- PMID
- 21856855
- PMCID
- PMC3209206
- ISSN
- 0021-9193
- eISSN
- 1098-5530
- Language
- English
- Date published
- 11/15/2011
- Academic Unit
- Microbiology and Immunology
- Record Identifier
- 9984083273002771
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