Plasticity of the Mre11-Rad50-Xrs2-Sae2 nuclease ensemble in the processing of DNA-bound obstacles

Genes Dev. 2017 Dec 1;31(23-24):2331-2336. doi: 10.1101/gad.307900.117. Epub 2018 Jan 10.

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.

Keywords: DNA end resection; Ku70–Ku80; MRX–Sae2; RPA; nuclease; nucleosome.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • DNA Cleavage
  • DNA End-Joining Repair*
  • DNA Repair / physiology*
  • DNA-Binding Proteins / metabolism
  • Endodeoxyribonucleases / metabolism
  • Endonucleases / metabolism*
  • Enzyme Activation / genetics
  • Exodeoxyribonucleases / metabolism
  • Exonucleases / metabolism*
  • Multienzyme Complexes / metabolism*
  • Multiprotein Complexes / metabolism
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / physiology*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*

Substances

  • DNA-Binding Proteins
  • Multienzyme Complexes
  • Multiprotein Complexes
  • RAD50 protein, S cerevisiae
  • SAE2 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • XRS2 protein, S cerevisiae
  • high affinity DNA-binding factor, S cerevisiae
  • Endodeoxyribonucleases
  • Endonucleases
  • Exodeoxyribonucleases
  • Exonucleases
  • MRE11 protein, S cerevisiae
  • exodeoxyribonuclease I