Concurrent D-loop cleavage by Mus81 and Yen1 yields half-crossover precursors

Nucleic Acids Res. 2024 Jul 8;52(12):7012-7030. doi: 10.1093/nar/gkae453.

Abstract

Homologous recombination involves the formation of branched DNA molecules that may interfere with chromosome segregation. To resolve these persistent joint molecules, cells rely on the activation of structure-selective endonucleases (SSEs) during the late stages of the cell cycle. However, the premature activation of SSEs compromises genome integrity, due to untimely processing of replication and/or recombination intermediates. Here, we used a biochemical approach to show that the budding yeast SSEs Mus81 and Yen1 possess the ability to cleave the central recombination intermediate known as the displacement loop or D-loop. Moreover, we demonstrate that, consistently with previous genetic data, the simultaneous action of Mus81 and Yen1, followed by ligation, is sufficient to recreate the formation of a half-crossover precursor in vitro. Our results provide not only mechanistic explanation for the formation of a half-crossover, but also highlight the critical importance for precise regulation of these SSEs to prevent chromosomal rearrangements.

MeSH terms

  • Crossing Over, Genetic*
  • DNA-Binding Proteins* / genetics
  • DNA-Binding Proteins* / metabolism
  • Endonucleases* / genetics
  • Endonucleases* / metabolism
  • Holliday Junction Resolvases / genetics
  • Holliday Junction Resolvases / metabolism
  • Homologous Recombination
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins* / genetics
  • Saccharomyces cerevisiae Proteins* / metabolism

Substances

  • Endonucleases
  • Saccharomyces cerevisiae Proteins
  • MUS81 protein, S cerevisiae
  • DNA-Binding Proteins
  • Yen1 protein, S cerevisiae
  • Holliday Junction Resolvases