Composition of the DNA-uptake complex of Vibrio cholerae.

Natural competence for transformation is a developmental program that allows certain bacteria to take up free extracellular DNA from the environment and integrate this DNA into their genome. Thereby, natural transformation acts as mode of horizontal gene transfer and impacts bacterial evolution. The number of genes induced upon competence induction varies significantly between organisms. However, all of the naturally competent bacteria possess competence genes that encode so-called DNA-uptake machineries. Some components of these multi-protein complexes resemble subunits of type IV pili and type II secretion systems. However, knowledge on the mechanistic aspects of such DNA-uptake complexes is still very limited. Here, we discuss some new findings regarding the DNA-uptake machinery of the naturally transformable human pathogen Vibrio cholerae. The potential of this organism to initiate the competence program was discovered less than a decade ago. However, recent studies have provided new insight into both the regulatory pathways of competence induction and into the DNA uptake dynamics.