The BceRS two-component regulatory system induces expression of the bacitracin transporter, BceAB, in Bacillus subtilis

Authors

  • Reiko Ohki,

    Corresponding author
    1. Department of Molecular Biology, School of Health Sciences, Kyorin University, 476 Miyashita, Hachiouji, Tokyo 192-0005, Japan.
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    • These authors contributed equally to this work.

  • Giyanto,

    1. Department of Bioinformatics and Genomics, Graduate School of Information Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0101, Japan.
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    • These authors contributed equally to this work.

  • Kozue Tateno,

    1. Department of Molecular Biology, School of Health Sciences, Kyorin University, 476 Miyashita, Hachiouji, Tokyo 192-0005, Japan.
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  • Waka Masuyama,

    1. Department of Bioinformatics and Genomics, Graduate School of Information Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0101, Japan.
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  • Shigeki Moriya,

    1. Department of Bioinformatics and Genomics, Graduate School of Information Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0101, Japan.
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  • Kazuo Kobayashi,

    1. Department of Bioinformatics and Genomics, Graduate School of Information Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0101, Japan.
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  • Naotake Ogasawara

    1. Department of Bioinformatics and Genomics, Graduate School of Information Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0101, Japan.
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E-mail ohkir@kyorin-u.ac.jp; Tel. (+81) 426 91 0011; Fax (+81) 426 91 1094.

Summary

BceA and bceB encode a nucleotide-binding domain (NBD) and membrane-spanning domain (MSD) subunit, respectively, of an ATP-binding cassette (ABC) transporter in Bacillus subtilis. Disruption of these genes resulted in hypersensitivity to bacitracin, a peptide antibiotic that is non-ribosomally synthesized in some strains of Bacillus. Northern hybridization analyses showed that expression of the bceAB operon is induced by bacitracin present in the growth medium. The bceRS genes encoding a two-component regulatory system are located immediately upstream of bceAB. Deletion analyses of the bceAB promoter together with DNase I footprinting experiments revealed that a sensor kinase, BceS, responds to extracellular bacitracin either directly or indirectly and transmits a signal to a cognate response regulator, BceR. The regulator binds directly to the upstream region of the bceAB promoter and upregulates the expression of bceAB genes. The bcrC gene product is additionally involved in bacitracin resistance. The expression of bcrC is dependent on the ECF σ factors, σM and σX, but not on the BceRS two-component system. In view of these results, possible roles of BceA, BceB and BcrC in bacitracin resistance of B. subtilis 168 are discussed.

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