Singled out for integration

摘要

Bacteria regularly swap genes among themselves. The structure of an enzyme that mediates the spread of certain DNA elements reveals the unusual way in which they take up residence in new genomes. The transfer of genes among bacteria is cr ucial in generating diversity, allowing bacteria to adapt quickly to changing environments. Mobile DNA elements called integron cassettes are major vehicles in such gene exchange. In this issue, MacDonald etal. (page 1157) report the structure of an enzyme that inserts these cassettes into genomes, providing some much-needed insight into how these ubiquitous genetic building-blocks move among bacteria.