Bacteria fix DNA like mammals

Bacteria and mammals may use similar mechanisms in a major yet poorly understood DNA repair pathway, suggests a report in the October 22 Science.

In theory, coauthor Aidan Doherty of the University of Sussex in Brighton told The Scientist, this system—uses of which are the subject of a patent filed by the University of Cambridge—should enable the cloning of any DNA fragments, regardless of the structure of the ends, and has great potential for the generation of random DNA libraries.

Non-homologous end joining (NHEJ) is the main pathway for resection and repair of DNA double-strand breaks (DSBs) with incompatible ends in mammalian cells. The mechanisms required in NHEJ are poorly understood. Many DSBs require processing by polymerases and nucleases to produce ligatable termini. The Mycobacterium tuberculosis DNA repair ligase, Mt-Lig, has domains exhibiting significant homology with polymerases and possibly nucleases, suggesting it might prove a model for NHEJ.

Doherty's team ...