Distinct sensory pathways in Vibrio cholerae El Tor and classical biotypes modulate cyclic dimeric GMP levels to control biofilm formation.

TitleDistinct sensory pathways in Vibrio cholerae El Tor and classical biotypes modulate cyclic dimeric GMP levels to control biofilm formation.
Publication TypeJournal Article
Year of Publication2009
AuthorsHammer, BK, Bassler, BL
JournalJ Bacteriol
Date Published2009 Jan
KeywordsBiofilms, Cloning, Molecular, Dimerization, DNA, Bacterial, Gene Library, Genes, Reporter, Guanosine Monophosphate, Homeostasis, Kinetics, Quorum Sensing, Restriction Mapping, Signal Transduction, Transcription, Genetic, Vibrio cholerae, Virulence

<p>Quorum sensing (QS), or cell-cell communication in bacteria, is achieved through the production and subsequent response to the accumulation of extracellular signal molecules called autoinducers (AIs). To identify AI-regulated target genes in Vibrio cholerae El Tor (V. cholerae(El)), the strain responsible for the current cholera pandemic, luciferase expression was assayed in an AI(-) strain carrying a random lux transcriptional reporter library in the presence and absence of exogenously added AIs. Twenty-three genes were identified and shown to require the QS transcription factor, HapR, for their regulation. Several of the QS-dependent target genes, annotated as encoding hypothetical proteins, in fact encode HD-GYP proteins, phosphodiesterases that degrade the intracellular second messenger cyclic dimeric GMP (c-di-GMP), which is important for controlling biofilm formation. Indeed, overexpression of a representative QS-activated HD-GYP protein in V. cholerae(El) reduced the intracellular concentration of c-di-GMP, which in turn decreased exopolysaccharide production and biofilm formation. The V. cholerae classical biotype (V. cholerae(Cl)), which caused previous cholera pandemics and is HapR(-), controls c-di-GMP levels and biofilm formation by the VieA signaling pathway. We show that the VieA pathway is dispensable for biofilm formation in V. cholerae(El) but that restoring HapR in V. cholerae(Cl) reestablishes QS-dependent repression of exopolysaccharide production. Thus, different pandemic strains of V. cholerae modulate c-di-GMP levels and control biofilm formation in response to distinct sensory pathways.</p>

Alternate JournalJ. Bacteriol.
PubMed ID18952786
PubMed Central IDPMC2612459
Grant List5R01A1054442 / / PHS HHS / United States
5R01GM065859 / GM / NIGMS NIH HHS / United States
F32-AI054033-01 / AI / NIAID NIH HHS / United States
R01 AI054442 / AI / NIAID NIH HHS / United States
/ / Howard Hughes Medical Institute / United States