Generating crossovers by resolution of nicked Holliday junctions: a role for Mus81-Eme1 in meiosis

Mol Cell. 2003 Sep;12(3):761-74. doi: 10.1016/s1097-2765(03)00343-5.


The double Holliday junction (dHJ) is generally regarded to be a key intermediate of meiotic recombination, whose resolution is critical for the formation of crossover recombinants. In fission yeast, the Mus81-Eme1 endonuclease has been implicated in resolving dHJs. Consistent with this role, we show that Mus81-Eme1 is required for generating meiotic crossovers. However, purified Mus81-Eme1 prefers to cleave junctions that mimic those formed during the transition from double-strand break to dHJ. Crucially, these junctions are cleaved by Mus81-Eme1 in precisely the right orientation to guarantee the formation of a crossover every time. These data demonstrate how crossovers could arise without forming or resolving dHJs using an enzyme that is widely conserved amongst eukaryotes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Crossing Over, Genetic / genetics
  • DNA / genetics
  • DNA / metabolism*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Endonucleases / genetics
  • Endonucleases / metabolism*
  • Meiosis / genetics*
  • Nucleic Acid Conformation
  • Recombination, Genetic / genetics*
  • Saccharomyces cerevisiae Proteins
  • Schizosaccharomyces / enzymology*
  • Schizosaccharomyces / genetics
  • Schizosaccharomyces pombe Proteins / genetics
  • Schizosaccharomyces pombe Proteins / metabolism*


  • DNA-Binding Proteins
  • Saccharomyces cerevisiae Proteins
  • Schizosaccharomyces pombe Proteins
  • DNA
  • Eme1 protein, S pombe
  • Endonucleases
  • MUS81 protein, S cerevisiae