The evolution of bacterial LuxI and LuxR quorum sensing regulators

• Published in: Microbiology (Society for General Microbiology) Vol. 147; no. 8; pp. 2379 - 2387
• Main Authors: Gray, Kendall M, Garey, James R
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.08.2001; Society for General Microbiology
• Subjects: Bacterial Proteins - genetics; Bacteriology; Biological and medical sciences; Evolution, Molecular; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Bacterial; Gene Transfer, Horizontal; Genes, rRNA - genetics; Genetics; LuxI gene; LuxR gene; Microbiology; Miscellaneous; Phylogeny; Proteobacteria; Proteobacteria - genetics; Proteobacteria - physiology; quorum sensing; Repressor Proteins - genetics; RNA, Ribosomal, 16S - genetics; Signal Transduction; Trans-Activators - genetics; Transcription Factors - genetics; Enzyme; Metabolite; Lactone; Phylogeny; Synthase; Mediation; Protein; Generation; Signal; Specificity; Bacteria; Evolution; Cell; Communication
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/00221287-147-8-2379

Department of Biology, University of South Florida, 4202 E. Fowler Ave, SCA 110, Tampa, FL 33620, USA 1 Author for correspondence: Kendall M. Gray. Tel: +1 206 543 9396. Fax: +1 206 616 6749. e-mail: kmg{at}u.washington.edu Quorum sensing is a widespread form of bacterial communication in which individual cells produce and respond to specific N -acyl homoserine lactone signal metabolites. The different autoinducer synthases that generate these signals and the receptor/activator proteins that mediate the cell’s response to them constitute evolutionarily conserved families of regulatory proteins known as the LuxI and LuxR families, respectively. We have performed a phylogenetic analysis of 76 individual LuxI and LuxR homologues present in diverse members of the Gram-negative Proteobacteria . The results were consistent with an early origin for these regulators during the evolution of the Proteobacteria , with functional pairs of luxI and luxR genes possibly coevolving as regulatory cassettes. In many cases, specific LuxI and LuxR family members appeared to have been inherited horizontally. In particular, those species containing multiple LuxI and/or LuxR homologues usually appeared to have obtained each individual homologue or functional pair of homologues from an independent source. Because multiple homologues interact to form regulatory cascades, this finding suggests that hierarchical signalling pathways can potentially evolve by the sequential integration of pre-existing regulatory circuits acquired from diverse sources. Keywords: intercellular signalling, cell–cell communication, horizontal gene transfer a Present address: Department of Microbiology, Box 357242, University of Washington, Seattle, WA 98195-7242, USA.