The katX gene of Bacillus subtilis is under dual control of sigmaB and sigmaF.
The gene katX, which encodes a catalase in Bacillus subtilis, is transcribed by EsigmaF in the pre-spore. This catalase is responsible for the resistance to hydrogen peroxide shown by germinating and outgrowing spores. We demonstrated that katX is also a sigmaB-dependent general stress gene, since it is strongly induced by heat, salt and ethanol stress, as well as by energy depletion. The -10 and -35 sequences of the sigmaB- and sigmaF-dependent promoters of katX overlap, and the transcriptional start points used by EsigmaB and EsigmaF differ by only one nucleotide. Our results indicate that the level of KatX level in outgrowing spores depends mainly on EsigmaF, because sigB mutants show normal KatX activity in dormant and outgrowing spores. katX mutants also develop the non-specific resistance to oxidative stress that is typical of glucose-starved cells. Therefore, the physiological role of sigmaB-dependent katX expression remains obscure. The results indicate an overlap between the sigmaB regulon and the sigmaF regulon, and the physiological implications of this overlap are discussed.
Petersohn
A
A
Institut für Mikrobiologie und Molekularbiologie, Ernst-Moritz-Arndt-Universität, Greifswald, Germany.
Engelmann
S
S
Setlow
P
P
Hecker
M
M
D029681:Arabidopsis Proteins; D001412:Bacillus subtilis / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D002374:Catalase / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D004351:Drug Resistance; D004790:Enzyme Induction; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008969:Molecular Sequence Data; D009154:Mutation; D018384:Oxidative Stress / Q000235:genetics; D010940:Plant Proteins / Q000302:isolation & purification; D012808:Sigma Factor / Q000378:metabolism*; D013171:Spores, Bacterial / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D014158:Transcription, Genetic
D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; C064971:FliA protein, Bacteria; C081231:KATA protein, Arabidopsis; D010940:Plant Proteins; C079011:SigB protein, Bacteria; D012808:Sigma Factor; D006861:Hydrogen Peroxide; C102664:hydroperoxidase II; D002374:Catalase