Expression of a stress- and starvation-induced dps/pexB-homologous gene is controlled by the alternative sigma factor sigmaB in Bacillus subtilis.
SigmaB-dependent general stress proteins (Gsps) of Bacillus subtilis are essential for the development of glucose-starvation-induced cross-resistance to oxidative challenge. However, the proteins directly involved in this nonspecific resistance to oxidative stress have to be identified. We found that one prominent Gsp displayed strong sequence similarity to the previously characterized oxidative-stress-inducible MrgA protein of B. subtilis and to the starvation-induced Dps/PexB protein of Escherichia coli. We therefore designated this prominent Gsp Dps. While MrgA belongs to the peroxide-stress-inducible proteins needed for the H2O2-inducible adaptive response to oxidative stress, Dps belongs to the proteins induced by heat, salt, or ethanol stress and after starvation for glucose but not by a sublethal oxidative challenge. Primer extension experiments identified two overlapping promoters upstream of the coding region of dps, one being sigmaB dependent (PB) and the other being sigmaB independent (P1). Both promoters contribute to the basal level of dps during growth. After stress or during entry into the stationary phase, transcription from PB strongly increased whereas transcription from P1 decreased. Mutant strains lacking Dps completely failed to develop glucose-starvation-induced resistance to oxidative stress. These results confirm our suggestion that sigmaB-dependent general stress proteins of B. subtilis are absolutely required for the development of nonspecific resistance to oxidative stress.
Antelmann
H
H
Institut für Mikrobiologie und Molekularbiologie, Ernst-Moritz-Arndt-Universität, Greifswald, Germany.
Engelmann
S
S
Schmid
R
R
Sorokin
A
A
Lapidus
A
A
Hecker
M
M
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics*; D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis / Q000235:genetics; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005947:Glucose / Q000172:deficiency; D008969:Molecular Sequence Data; D018384:Oxidative Stress; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D012808:Sigma Factor / Q000378:metabolism*; D014158:Transcription, Genetic
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C083911:DPS protein, Bacteria; D029968:Escherichia coli Proteins; C095506:MrgA protein, Bacillus subtilis; C079011:SigB protein, Bacteria; D012808:Sigma Factor; C088010:dps protein, E coli; D005947:Glucose