Multiple interactions among the competence proteins of <i>Bacillus subtilis</i>

Kramer, Naomi E.; Hahn, Jeanette; Dubnau, David

doi:10.1111/j.1365-2958.2007.05799.x

Cited by 90 publications

(123 citation statements)

References 33 publications

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“…Previously, it was shown by Förster resonance energy transfer that DprA interacts with RecA in vivo (4). To test whether DprA physically interacted with RecA in vitro, we used a Ni 2ϩ column and purified His-tagged DprA and native RecA (Fig.…”

Section: Analysis Ofmentioning

confidence: 99%

“…With few exceptions, natural transformation, which is a widely distributed mechanism for genetic recombination (GR) 4 in many bacterial genera, is transiently induced (competence state) (1,3). The competence machinery actively processes exogenous dsDNA and takes up the internalized ssDNA to replace homologous (or partially homologous) chromosomal sequences in a mechanism catalyzed by RecA with the help of accessory factors (2,3).…”

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confidence: 99%

“…The membrane-associated proteins, which form the DNA uptake machinery, bind environmental dsDNA, degrade one of the strands to produce ssDNA, and internalize it into the cytosol (1). The functional DNA uptake machinery is required for the localization of the cytosolic recombination proteins to the cell pole (4).…”

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confidence: 99%

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Bacillus subtilis DprA Recruits RecA onto Single-stranded DNA and Mediates Annealing of Complementary Strands Coated by SsbB and SsbA

Yadav

Carrasco

Hejna

et al. 2013

Journal of Biological Chemistry

125

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Background: Different mediators assist RecA to catalyze genetic recombination. Results: DprA facilitates the displacement of both SSBs (SsbB and SsbA), increases RecA nucleation onto SSB-coated ssDNA, and mediates DNA strand annealing. Conclusion: DprA facilitates RecA-mediated strand exchange and anneals complementary strands coated by an SSB protein.Significance: RecA-dependent chromosomal transformation and RecA-independent plasmid transformation require the competence-induced DprA mediator.

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Section: Analysis Ofmentioning

confidence: 99%

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confidence: 99%

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Bacillus subtilis DprA Recruits RecA onto Single-stranded DNA and Mediates Annealing of Complementary Strands Coated by SsbB and SsbA

Yadav

Carrasco

Hejna

et al. 2013

Journal of Biological Chemistry

125

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“…Interestingly, the majority of competence-protein localization studies using cellular microbiology approaches are based on studies performed with the Gram-positive bacterium Bacillus subtilis. For B. subtilis, a multicomponent protein machine may be responsible for DNA uptake (1,7,8), as many transformation proteins colocalize to the pole(s) of the cell (9)(10)(11)(12). Furthermore, using single-molecule experiments with laser tweezers, Hahn et al showed that DNA binding and uptake also occur preferentially at the cell pole (9).…”

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confidence: 99%

DNA-uptake machinery of naturally competent Vibrio cholerae

Seitz

Blokesch

2013

Proc. Natl. Acad. Sci. U.S.A.

160

247

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Natural competence for transformation is a mode of horizontal gene transfer that is commonly used by bacteria to take up DNA from their environment. As part of this developmental program, so-called competence genes, which encode the components of a DNA-uptake machinery, are expressed. Several models have been proposed for the DNA-uptake complexes of competent bacteria, and most include a type IV (pseudo)pilus as a core component. However, cell-biology-based approaches to visualizing competence proteins have so far been restricted to Gram-positive bacteria. Here, we report the visualization of a competence-induced pilus in the Gram-negative bacterium Vibrio cholerae. We show that piliated cells mostly contain a single pilus that is not biased toward a polar localization and that this pilus colocalizes with the outer membrane secretin PilQ. PilQ, on the other hand, forms several foci around the cell and occasionally colocalizes with the dynamic cytoplasmic-traffic ATPase PilB, which is required for pilus extension. We also determined the minimum competence regulon of V. cholerae, which includes at least 19 genes. Bacteria with mutations in those genes were characterized with respect to the presence of surface-exposed pili, DNA uptake, and natural transformability. Based on these phenotypes, we propose that DNA uptake in naturally competent V. cholerae cells occurs in at least two steps: a pilus-dependent translocation of the incoming DNA across the outer membrane and a pilus-independent shuttling of the DNA through the periplasm and into the cytoplasm.N atural competence for genetic transformation is one of three modes of horizontal gene transfer (HGT) in prokaryotes and is often tightly regulated (1-3). Large pieces of DNA containing a series of genes can be transferred by natural transformation without the need for direct interaction with other microbes or mobile genetic elements. This process can foster rapid evolution, and HGT is known to be involved in the spread of antibiotic resistance, adaptation to new environmental niches, and the emergence of new pathogens.Many bacterial species are able to enter a state of natural competence, including the human pathogen Vibrio cholerae. In this bacterium, competence is induced upon growth on chitinous surfaces (3, 4), the natural habitat of V. cholerae (5). Although we have gained a reasonably clear understanding of the regulatory network driving competence induction in this organism (for a review, see ref.3), almost nothing is known about its DNAuptake machinery. Indeed, the sophisticated DNA-uptake complexes used by naturally competent bacteria during transformation are still poorly characterized (6), especially in Gram-negative bacteria in which the transforming DNA (tDNA) must cross two membranes and the periplasmic space (including the peptidoglycan layer) to enter the cytoplasm and recombine with the chromosome (the latter step is not required if the tDNA consists of plasmid DNA). Interestingly, the majority of competence-protein localization studies using cellu...

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“…(Note that, unless stated otherwise, the indicated genes and products are of B. subtilis origin. 5 ) Previously, it has been postulated that RecA loading onto the internalized ssDNA is a multistep processes. First, the ssDNA is coated mostly either by DprA (8), by SsbB (9), or by SsbA as soon as it leaves the entry channel of the uptake apparatus (4).…”

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confidence: 99%