Targets of the master regulator of biofilm formation in Bacillus subtilis

Authors

  • Frances Chu,

    1. Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
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  • Daniel B. Kearns,

    1. Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
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    • Department of Biology, Indiana University, Bloomington, IN 47408, USA.

  • Steven S. Branda,

    1. Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115, USA.
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    • Present addresses: Biosystems Research, Sandia National Laboratories, Livermore, CA 94551, USA.

  • Roberto Kolter,

    1. Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115, USA.
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  • Richard Losick

    Corresponding author
    1. Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
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*E-mail losick@mcb.harvard.edu; Tel. (+1) 617 495 4905; Fax (+1) 617 496 4642.

Summary

Wild strains of the spore-forming bacterium Bacillus subtilis are capable of forming architecturally complex communities of cells. The formation of these biofilms is mediated in part by the 15-gene exopolysaccharide operon, epsA-O, which is under the direct negative control of the SinR repressor. We report the identification of an additional operon, yqxM-sipW-tasA, that is required for biofilm formation and is under the direct negative control of SinR. We now show that all three members of the operon are required for the formation of robust biofilms and that SinR is a potent repressor of the operon that acts by binding to multiple sites in the promoter region. Genome-wide analysis of SinR-controlled transcription indicates that the epsA-O and yqxM-sipW-tasA operons constitute many of the most strongly controlled genes in the SinR regulon. These findings reinforce the view that SinR is a master regulator for biofilm formation and further suggest that a principal biological function of SinR is to govern the assembly of complex multicellular communities.

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