Editor's Summary

9 October 2008

DNA repair: at 3's and 5's


For years, researchers working on DNA repair have faced a conundrum: homologous recombination, a process that repairs double-strand DNA breaks, requires the production of single-stranded DNA tails with a 3' end. Yet the obvious candidate for an exonuclease to function in this process is the Mre11 complex, which generates 5' tailed molecules. Eleni Mimitou and Lorraine Symington now introduce some clarity into the situation. The cell's trick is to use a two-step process in which a short oligonucleotide is first removed from one strand by the Mre11 complex, and then the exonuclease ExoI and helicase Sgs1 load onto this substrate to generate the 3'-tailed molecule.

News and ViewsMolecular biology: DNA endgames

If it is not repaired efficiently, damage to DNA double strands can have dire consequences for both the cell and the organism. Given the gravity of this situation, cells use two pathways to start the process.

Hannah L. Klein

doi:10.1038/455740a

ArticleSae2, Exo1 and Sgs1 collaborate in DNA double-strand break processing

Eleni P. Mimitou & Lorraine S. Symington

doi:10.1038/nature07312