Reginato, Giordano Cannavo, Elda Cejka, Petr 2017 DNA double-strand break repair by homologous recombination is initiated by DNA end resection, which is commenced by the Mre11–Rad50–Xrs2 complex and Sae2 in yeast. Here we report that the nonhomologous end joining factor Ku limits the exonuclease activity of Mre11 and promotes its endonuclease to cleave 5'-terminated DNA strands at break sites. Following initial endonucleolytic cleavage past the obstacle, Exo1 specifically extends the resection track, leading to the generation of long 3' overhangs that are required for homologous recombination. These experiments provide mechanistic insights into how short-range and long-range DNA end resection enzymes overcome obstacles near broken DNA ends to initiate recombination. application/pdf https://susi.usi.ch/global/documents/318798 https://n2t.net/ark:/12658/srd1318798 https://susi.usi.ch/documents/318798/files/1576_Reginato2017.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1101/gad.308254.117 info:eu-repo/semantics/altIdentifier/ark/12658/srd1318798 info:eu-repo/semantics/openAccess CC BY-NC Genes and Development. - Cold Spring Harbor Laboratory Press. - 2017, vol. 31, no. 23-24, p. 2325-2330 homologous recombination DNA nuclease yMre11 Sae2 Ku70–80 DNA end resection info:eu-repo/classification/udc/57 Physiological protein blocks direct the Mre11–Rad50–Xrs2 and Sae2 nuclease complex to initiate DNA end resection http://purl.org/coar/resource_type/c_6501