Unmasking an ancestral mechanism of integrons - key players in antibiotic resistance

With the ultimate aim of combating antibiotic resistance acquired by bacteria during evolution, researchers from the Institut Pasteur and CNRS have managed to shed light on one of the mechanisms of DNA recombination in bacteria.

Resistance genes are transferred between pathogenic bacteria via different pathways, but always as a single strand of DNA. One of the main players in these transfers is the integron - a genetic element that enables bacteria to acquire new genes and quickly adapt to environmental stress. The new genes are located in a structure called a "cassette" for integration into the bacteria's genome. Cassette integration reactions are controlled by a recombinase - the integrase - which is synthesized by the integron. These are atypical reactions in terms of DNA recombination, as the site in the cassettes is structurally different from traditional sites in other recombinant systems.

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