Affiliation:
1. Division of Basic Biomedical Sciences, University of South Dakota, Vermillion, South Dakota 57069, and Center for Infectious Disease Research and Vaccinology, South Dakota State University, Brookings, South Dakota 57007
Abstract
ABSTRACT
The scavenging of reactive oxygen species (ROS) within cells is regulated by several interacting factors, including transcriptional regulators. Involvement of
sarA
family genes in the regulation of proteins involved in the scavenging of ROS is largely unknown. In this report, we show that under aerobic conditions, the levels of
sodM
and s
odA
transcription, in particular the
sodM
transcript, are markedly enhanced in the
sarA
mutant among the tested
sarA
family mutants. Increased levels of
sod
expression returned to near the parental level in a single-copy
sarA
complemented strain. Under microaerophilc conditions, transcription of both
sodM
and
sodA
was considerably enhanced in the
sarA
mutant compared to the wild-type strain. Various genotypic, phenotypic, and DNA binding studies confirmed the involvement of SarA in the regulation of
sod
transcripts in different strains of
Staphylococcus aureus
. The
sodA
mutant was sensitive to an oxidative stress-inducing agent, methyl viologen, but the
sarA sodA
double mutant was more resistant to the same stressor than the single
sodA
mutant. These results suggest that overexpression of SodM, which occurs in the
sarA
background, can rescue the methyl viologen-sensitive phenotype observed in the absence of the
sodA
gene. Analysis with various oxidative stress-inducing agents indicates that SarA may play a greater role in modulating oxidative stress resistance in
S. aureus
. This is the first report that demonstrates the direct involvement of a regulatory protein (SarA) in control of
sod
expression in
S. aureus
.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
52 articles.
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