Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Sci. STKE, 8 January 2002
Vol. 2002, Issue 114, p. tw6
[DOI: 10.1126/stke.2002.114.tw6]


Microbiology Quorum Sensing a New Way

Bacteria can detect their density and alter their behavior based on the accumulation and detection of secreted signaling molecules in a process called quorum sensing. Haas et al. showed that, in Enterococcus faecalis, the toxin cytolysin acts to induce its own production through a quorum-sensing signaling cascade. The quorum-sensing and increased transcriptional activity of the operon requires the presence of two genes (cylR1 and cylR2), located upstream of the cytolysin operon and oriented opposite to the operon for the purposes of expression. These two genes encode novel proteins: cylR1 encodes a protein with three predicted transmembrane helices (the putative receptor), and cylR2 encodes a protein with a helix-turn-helix DNA binding motif (the putative response regulator). Using a reporter construct, Haas et al. showed that mutation of deletion of either of cylR1or cylR2 resulted in constitutive activity of the cyl promoter and loss of cytolysin-stimulated increase in gene expression. Dunny discusses how this cytolysin pathway represents a third mechanism for quorum-sensing, in addition to the known two-component histidine kinase pathways and the import to intracellular receptor signaling pathways.

W. Haas, B. D. Shepard, M. S. Gilmore, Two-component regulator of Enterococcus faecalis cytolysin responds to quorum-sensing autoinduction. Nature 415, 84-87 (2002). [Online Journal]

G. M. Dunny, Group effort in toxin synthesis. Nature 415, 33-34 (2002). [Online Journal]

Citation: Quorum Sensing a New Way. Sci. STKE 2002, tw6 (2002).

To Advertise     Find Products

Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882