title: Genetics of Natural Competence in Vibrio cholerae and other Vibrios.
abstract: Many Gram-positive and Gram-negative bacteria can become naturally competent to take up extracellular DNA from the environment via a dedicated uptake apparatus. The genetic material that is acquired can (i) be used for nutrients, (ii) aid in genome repair, and (iii) promote horizontal gene transfer when incorporated onto the genome by homologous recombination, the process of "transformation." Recent studies have identified multiple environmental cues sufficient to induce natural transformation in Vibrio cholerae and several other Vibrio species. In V. cholerae, nutrient limitation activates the cAMP receptor protein regulator, quorum-sensing signals promote synthesis of HapR-controlled QstR, chitin stimulates production of TfoX, and low extracellular nucleosides allow CytR to serve as an additional positive regulator. The network of signaling systems that trigger expression of each of these required regulators is well described, but the mechanisms by which each in turn controls competence apparatus genes is poorly understood. Recent work has defined a minimal set of genes that encode apparatus components and begun to characterize the architecture of the machinery by fluorescence microscopy. While studies with a small set of V. cholerae reference isolates have identified regulatory and competence genes required for DNA uptake, future studies may identify additional genes and regulatory connections, as well as revealing how common natural competence is among diverse V. cholerae isolates and other Vibrio species.
authors.affiliation: Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720.
authors.forename: Elena S
authors.initials: ES
authors.lastname: Antonova
authors.affiliation: School of Biology, Georgia Institute of Technology, Atlanta, GA 30332-0230.
authors.forename: Brian K
authors.initials: BK
authors.lastname: Hammer
mesh_terms: D001692:Biological Transport / Q000235:genetics; D002686:Chitin / Q000378:metabolism; D002373:Cyclic AMP Receptor Protein / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D061269:DNA Transformation Competence / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics; D004789:Enzyme Activation; D036781:Fimbriae Proteins / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D022761:Gene Transfer, Horizontal / Q000235:genetics*; D018933:Pili, Sex / Q000235:genetics; D053038:Quorum Sensing / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics; D014734:Vibrio cholerae / Q000235:genetics* / Q000472:pathogenicity
chemical_list: D002373:Cyclic AMP Receptor Protein; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D002686:Chitin; D036781:Fimbriae Proteins; D004247:DNA