Genetic competence in  : mechanismsand biological implications

Hofreuter, Dirk; Odenbreit, Stefan; Puls, Jürgen; Schwan, Dorothee; Haas, Rainer

doi:10.1016/s0923-2508(00)00164-9

Cited by 44 publications

(29 citation statements)

References 18 publications

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“…The fact that this system actively imports DNA emphasizes the unique and social nature of the transfer of chromosomal DNA between Sulfolobus cells. Other known DNA uptake systems such as competence systems only take up DNA from the environment, but not from other cells (36,37). How DNA is exported from the donor cell is still unclear.…”

Section: Discussionmentioning

confidence: 99%

The archaeal Ced system imports DNA

Wolferen

Wagner

Does

et al. 2016

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

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The intercellular transfer of DNA is a phenomenon that occurs in all domains of life and is a major driving force of evolution. Upon UV-light treatment, cells of the crenarchaeal genus Sulfolobus express Ups pili, which initiate cell aggregate formation. Within these aggregates, chromosomal DNA, which is used for the repair of DNA double-strand breaks, is exchanged. Because so far no clear homologs of bacterial DNA transporters have been identified among the genomes of Archaea, the mechanisms of archaeal DNA transport have remained a puzzling and underinvestigated topic. Here we identify saci_0568 and saci_0748, two genes from Sulfolobus acidocaldarius that are highly induced upon UV treatment, encoding a transmembrane protein and a membrane-bound VirB4/HerA homolog, respectively. DNA transfer assays showed that both proteins are essential for DNA transfer between Sulfolobus cells and act downstream of the Ups pili system. Our results moreover revealed that the system is involved in the import of DNA rather than the export. We therefore propose that both Saci_0568 and Saci_0748 are part of a previously unidentified DNA importer. Given the fact that we found this transporter system to be widely spread among the Crenarchaeota, we propose to name it the Crenarchaeal system for exchange of DNA (Ced). In this study we have for the first time to our knowledge described an archaeal DNA transporter.Archaea | DNA transport | conjugation | type IV pili | VirB4

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Section: Discussionmentioning

confidence: 99%

The archaeal Ced system imports DNA

Wolferen

Wagner

Does

et al. 2016

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

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“…A portion of these genes encode a type IV secretion system (T4SS) and a single known effector molecule, CagA (13). T4SSs are ancestrally related to conjugation systems and can be grouped according to their function into three categories: (i) DNA transfer (best characterized system for DNA transfer between gram-negative bacteria), (ii) DNA uptake and release, and (iii) effector translocation (11,17,27,28,30,58). The T4SS of H. pylori belongs to the effector translocator group of T4SSs.…”

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confidence: 99%

Interaction with CagF Is Required for Translocation of CagA into the Host via theHelicobacter pyloriType IV Secretion System

et al. 2006

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Development of severe gastric diseases is strongly associated with those strains of Helicobacter pylori that contain the cag pathogenicity island (PAI) inserted into the chromosome. The cag PAI encodes a type IV secretion system that translocates the major disease-associated virulence protein, CagA, into the host epithelial cell. CagA then affects host signaling pathways, leading to cell elongations and inflammation. Since the precise mechanism by which the CagA toxin is translocated by the type IV secretion system remained elusive, we used fusion proteins and immunoprecipitation studies to identify CagA-interacting secretion components. Here we demonstrate that CagA, in addition to other yet-unidentified proteins, interacts with CagF, presumably at the inner bacterial membrane. This interaction is required for CagA translocation, since an isogenic nonpolar cagF mutant was translocation deficient. Our results suggest that CagF may be a protein with unique chaperone-like function that is involved in the early steps of CagA recognition and delivery into the type IV secretion channel.

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“…Finally, transformation involves the uptake of free DNA from the environment followed by recombination into the genome. A number of bacterial species, such as Bacillus subtilis, Neisseria gonorrhoeae, and Helicobacter pylori, are known to be naturally competent for transformation (17,21,26). Conjugation and transduction are caused by extrachromosomal genetic elements acting in a "selfish" manner and are mechanistically independent of the recipient's genotype.…”

mentioning

confidence: 99%

Rapid Evolution of Diminished Transformability in Acinetobacter baylyi

2006

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The reason for genetic exchange remains a crucial question in evolutionary biology. Acinetobacter baylyi strain ADP1 is a highly competent and recombinogenic bacterium. We compared the parallel evolution of wild-type and engineered noncompetent lineages of A. baylyi in the laboratory. If transformability were to result in an evolutionary benefit, it was expected that competent lineages would adapt more rapidly than noncompetent lineages. Instead, regardless of competency, lineages adapted to the same extent under several laboratory conditions. Furthermore, competent lineages repeatedly evolved a much lower level of transformability. The loss of competency may be due to a selective advantage or the irreversible transfer of loss-of-function alleles of genes required for transformation within the competent population.

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Genetic competence in : mechanismsand biological implications

Cited by 44 publications

References 18 publications

The archaeal Ced system imports DNA

The archaeal Ced system imports DNA

Interaction with CagF Is Required for Translocation of CagA into the Host via theHelicobacter pyloriType IV Secretion System

Rapid Evolution of Diminished Transformability in Acinetobacter baylyi

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