Bacillus subtilis operon under the dual control of the general stress transcription factor [sigma]B and the sporulation transcription factor [sigma]H.
Varon, Debora +; Brody, Margaret S.; Price, Chester W. *
[Article] Molecular Microbiology. 20(2):339-350, April 1996.

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Summary: The [sigma]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 [sigma]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 [sigma]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::Tn917lac 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 [sigma]B-dependent promoter which is strongly induced by the addition of salt to logarithmically growing cells. The csb40 operon also has a second, [sigma]H-dependent promoter that is unaffected by salt addition. These results provide support for the hypothesis that [sigma]B controls a general stress regulon, and indicate that the [sigma]B and [sigma]H regulons partly overlap. We suggest that in addition to its acknowledged role in the sporulation process, [sigma]H is also involved in controlling a subclass of genes that are broadly involved in a general stress response.

(C) 1996 Blackwell Science Ltd.