DNA uptake during bacterial transformation

  title={DNA uptake during bacterial transformation},
  author={Inês Chen and David Dubnau},
  journal={Nature Reviews Microbiology},
Naturally competent bacteria are able to take up exogenous DNA and undergo genetic transformation. The transport of DNA from the extracellular milieu into the cytoplasm is a complex process, and requires proteins that are related to those involved in the assembly of type IV pili and type II secretion systems, as well as a DNA translocase complex at the cytoplasmic membrane. Here, we will review the current knowledge of DNA transport during transformation. 
Roles of Extracellular DNA in Bacterial Ecosystem
Extracellular DNA in the natural environment is a source of nutrients and gene pools for bacteria, and in sediments and biofilms, gene transfer must occur among bacteria via extracellularDNA through gene exchange and mutation to generate diversity.
The Ins and Outs of DNA Transfer in Bacteria
All or nearly all the machine components involved in transformation and conjugation have been identified and here the models for their roles in DNA transport are presented.
Membrane-associated DNA transport machines.
The FtsK/SpoIIIE proteins carry out the translocation of double-stranded DNA to ensure complete chromosome segregation during cell division and the transformation machine processes this internalized DNA and mediates its recombination with the resident chromosome during and after uptake.
Composition of the DNA-uptake complex of Vibrio cholerae
Recent studies have provided new insight into both the regulatory pathways of competence induction and into the DNA uptake dynamics of the naturally transformable human pathogen Vibrio cholerae.
CELL DIVISION AND SPORULATION General Features of DNA Transport in Cell
The FtsK/SpoIIIE proteins carry out the translocation of double-stranded DNA to ensure complete chromosome segregation during cell division and the transformation machine processes this internalized DNA and mediates its recombination with the resident chromosome during and after uptake.
The genetic transformation machinery: composition, localization, and mechanism.
A series of observations made in Bacillus subtilis and Streptococcus pneumoniae led to the recent emergence of a picture of a unique, highly integrated machine localized at the cell poles, which is proposed to name the transformasome.
A Type IV Pilus Mediates DNA Binding during Natural Transformation in Streptococcus pneumoniae
It is proposed that the transformation pilus is the primary DNA receptor on the bacterial cell during transformation in S. pneumoniae, a major Gram-positive human pathogen to acquire resistance to antibiotics and to escape vaccines through the binding and incorporation of new genetic material.
DNA Transport across the Outer and Inner Membranes of Naturally Transformable Vibrio cholerae Is Spatially but Not Temporally Coupled
This work indirectly visualized the transfer of the external DNA from outside the cell into the periplasm followed by the shuttling of the DNA into the cytoplasm of V. cholerae and provided evidence that the DNA translocation across the membranes is spatially but not temporally coupled.
Alternative Ways to Exchange DNA: Unconventional Conjugation Among Bacteria
In addition to asexual reproduction, many prokaryotes contain specific apparatus evolved to exchange DNA through their envelopes by direct cell-to-cell contacts, allowing the horizontal transfer of


DNA transport during transformation.
The process of DNA transport in competent bacteria is reviewed and two kinds of machineries have been described which show similarities to the proteins involved in biogenesis of type IV pili and type II secretion systems.
DNA uptake in bacteria.
  • D. Dubnau
  • Biology
    Annual review of microbiology
  • 1999
The mechanism of DNA uptake in both gram-positive and gram-negative bacteria is reviewed, and the similarity of certain essential competence proteins to those required for the assembly of type-4 pili and for type-2 protein secretion is discussed.
A competence regulon in Streptococcus pneumoniae revealed by genomic analysis
Six loci were discovered that composed a competence‐induced regulon that shared a consensus promoter sequence and encoded proteins, some of which were similar to proteins involved in DNA processing during transformation in other bacteria.
Internalizing DNA.
Uptake of transforming DNA in Gram‐positive bacteria: a view from Streptococcus pneumoniae
It is concluded that recruitment of EndA can occur in the absence of ComEC or ComFA and that EndA is active even when the single strands it produces are not pulled into the cell, indicating that DprA is required at a later stage in transformation.
Natural Transformation of Campylobacter jejuni Requires Components of a Type II Secretion System
ABSTRACT The human pathogen Campylobacter jejuni is one of more than 40 naturally competent bacterial species able to import macromolecular DNA from the environment and incorporate it into their
Induction of natural competence in Streptococcus pneumoniae triggers lysis and DNA release from a subfraction of the cell population
It is shown that induction of the competent state initiates release of DNA from a subfraction of the bacterial population, probably by cell lysis, which provides a natural mechanism for genetic recombination that resembles sex in higher organisms.
Competence for natural transformation in Neisseria gonorrhoeae: components of DNA binding and uptake linked to type IV pilus expression
It is shown here that DNA binding and uptake are resolvable events, and the existence of a robust, non‐specific DNA‐binding activity associated with the expression of both Tfp and PilT, which is unrelated to transformation but obscures the observation of specific binding events.
Directional transport and integration of donor DNA in Haemophilus influenzae transformation.
It appears that donor DNA undergoes degradation from an end prior to recombining with the chromosome as seen in Haemophilus influenzae transformation with a plasmid clone of homologous DNA (pCML6).