DNA double-strand break processing: the beginning of the end

Nucleolytic processing of DNA double-strand breaks (DSBs) generates 3' ssDNA tails that are essential for the assembly of DNA damage checkpoint signaling and DNA repair protein complexes. Genetic studies have provided evidence that multiple nuclease activities are involved in DSB end resection. Three recent studies, including work by Jackson and colleagues (pp. 2767- 2772) in the October 15, 2008, issue of Genes & Development, have begun to shed some light on the intricacy of this process.