Research Paper

Role of luxS in Bacillus anthracis growth and virulence factor expression

Volume 1, Issue 2   March/April 2010
Pages 72 - 83
http://dx.doi.org/10.4161/viru.1.2.10752
Authors: Marcus B. Jones, Scott N. Peterson, Rosslyn Benn, John C. Braisted, Behnam Jarrahi, Kenneth Shatzkes, Dacheng Ren, Thomas K. Wood and Martin J. Blaser

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Abstract:
Quorum-sensing (QS), the regulation of bacterial gene expression in response to changes in cell density, involves pathways that synthesize signaling molecules (auto-inducers). The luxS/AI-2-mediated QS system has been identified in both Gram-positive and Gram-negative bacteria. Bacillus anthracis, the etiological agent of anthrax, possesses genes involved in luxS/AI-2-mediated QS, and deletion of luxS in B. anthracis Sterne strain 34F2 results in inhibition of AI-2 synthesis and a growth defect. In the present study, we created a ΔluxS B. anthracis strain complemented in trans by insertion of a cassette, including luxS and a gene encoding erythromycin resistance, into the truncated plcR regulator locus. The complemented ΔluxS strain has restored AI-2 synthesis and wild-type growth. A B. anthracis microarray study revealed consistent differential gene expression between the wild-type and ΔluxS strain, including downregulation of the B. anthracis S-layer protein gene EA1 and pXO1 virulence genes. These data indicate that B. anthracis may use luxS/AI-2-mediated QS to regulate growth, density-dependent gene expression and virulence factor expression.

Received: September 21, 2009; Accepted: November 30, 2009

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