Plasticity of the Mre11–Rad50–Xrs2–Sae2 nuclease ensemble in the processing of DNA-bound obstacles
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA
- Corresponding author: patrick.sung{at}yale.edu
Abstract
The budding yeast Mre11–Rad50–Xrs2 (MRX) complex and Sae2 function together in DNA end resection during homologous recombination. Here we show that the Ku complex shields DNA ends from exonucleolytic digestion but facilitates endonucleolytic scission by MRX with a dependence on ATP and Sae2. The incision site is enlarged into a DNA gap via the exonuclease activity of MRX, which is stimulated by Sae2 without ATP being present. RPA renders a partially resected or palindromic DNA structure susceptible to MRX–Sae2, and internal protein blocks also trigger DNA cleavage. We present models for how MRX–Sae2 creates entry sites for the long-range resection machinery.
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Supplemental material is available for this article.
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Article published online ahead of print. Article and publication date are online at http://www.genesdev.org/cgi/doi/10.1101/gad.307900.117.
- Received October 3, 2017.
- Accepted December 7, 2017.
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