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Bacillus subtilis operon under the dual control of the general stress transcription factor σ B and the sporulation transcription factor σ H
Author(s) -
Varón Débora,
Brody Margaret S.,
Price Chester W.
Publication year - 1996
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1996.tb02621.x
Subject(s) - regulon , operon , biology , bacillus subtilis , genetics , transcription factor , promoter , transcription (linguistics) , gene , microbiology and biotechnology , gene expression , escherichia coli , bacteria , linguistics , philosophy
Summary The σ B transcription factor of Bacillus subtilis is activated in response to a variety of environmental stresses, including those imposed by entry into the stationary‐growth phase, and by heat, salt or ethanol challenge to logarithmically growing cells. Although σ B is thought to control a general stress regulon, the range of cellular functions it directs remains largely unknown. Our approach to understand the physiological role of σ B is to characterize genes that require this factor for all or part of their expression, i.e. the csb genes. In this study, we report that the transposon insertion csb40:: Tn 917lac identifies an operon with three open reading frames, the second of which resembles plant proteins induced by desiccation stress. Primer‐extension and operon‐fusion experiments showed that the csb40 operon has a σ B ‐dependent promoter which is strongly induced by the addition of salt to logarithmically growing cells. The csb40 operon also has a second, σ H ‐dependent promoter that is unaffected by salt addition. These results provide support for the hypothesis that σ B controls a general stress regulon, and indicate that the σ B and σ H regulons partly overlap. We suggest that in addition to its acknowledged role in the sporulation process, σ H is also involved in controlling a subclass of genes that are broadly involved in a general stress response.