Jones, M. B., Peterson, S. N., Benn, R., Braisted, J. C., Jarrahi, B., Shatzkes, K., Ren, D., Wood, T. K., Blaser, M. J.
Role of LuxS In Bacillus anthracis Growth and Virulence Factor Expression
Virulence. 2010 Oct 27; 1(2): 72-83.
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 DeltaluxS 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 DeltaluxS 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 DeltaluxS 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.