Spx-dependent global transcriptional control is induced by thiol-specific oxidative stress in Bacillus subtilis

Shunji Nakano, Elke Küster-Schöck, Alan D. Grossman, Peter Zuber

    Research output: Contribution to journalArticlepeer-review

    209 Scopus citations


    The Spx protein of Bacillus subtilis represses activator-stimulated transcription by interacting with the C-terminal domain of RNA polymerase (RNAP) α subunit. Its concentration increases in cells lacking the ATP-dependent protease, ClpXP, resulting in severe effects on growth and developmental processes. Microarray analysis was undertaken to identify genes that are induced or repressed when Spx interacts with RNAP. The induced genes included those encoding products known to function in maintaining thiol homeostasis. Two genes, thioredoxin (trxA) and thioredoxin reductase (trxB), are transcriptionally induced under conditions of thiol-specific oxidative (disulfide) stress by a mechanism involving Spx-RNAP interaction. Disulfide stress also results in an increase in Spx-dependent transcriptional repression. The increase in Spx activity in cells encountering disulfide stress is due in part to a posttranscriptional mechanism of spx control resulting in an increase in Spx concentration. An spx null mutant and a strain bearing an allele of rpoA that prevents Spx-RNAP interaction show hypersensitivity to disulfide stress. From these results, it is proposed that Spx is an activator that mobilizes the operations necessary to reverse the effects of oxidative damage, but it also serves as a negative regulator that causes the postponement of developmental programs and energy-consuming growth-related functions while the cell copes with the period of stress.

    Original languageEnglish (US)
    Pages (from-to)13603-13608
    Number of pages6
    JournalProceedings of the National Academy of Sciences of the United States of America
    Issue number23
    StatePublished - Nov 11 2003


    • ClpXP
    • Disulfide stress
    • Transcription activation

    ASJC Scopus subject areas

    • General


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