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The P. furiosus mre11/rad50 complex promotes 5' strand resection at a DNA double-strand break

Ben B Hopkins1, Tanya T Paull

  • 1The Howard Hughes Medical Institute, Department of Molecular Genetics and Microbiology, University of Texas at Austin, Austin, TX 78712, USA.

Cell
|October 30, 2008
PubMed

Insights

The Mre11/Rad50 complex, with HerA and NurA, processes DNA double-strand breaks (DSBs) in archaea. This generates essential 3' single-stranded DNA for homologous recombination repair, offering insights into eukaryotic DNA repair mechanisms.

Area of Science:

  • Molecular Biology
  • Genetics
  • Biochemistry

Background:

  • The Mre11/Rad50 complex is crucial for DNA double-strand break (DSB) repair via homologous recombination.
  • Its enzymatic activity alone is insufficient for generating the 3' single-stranded DNA required for recombinase loading.

Purpose of the Study:

  • To investigate the cooperative function of Mre11/Rad50 with HerA and NurA in DNA end resection in archaea.
  • To elucidate the mechanism of DSB processing in thermophilic archaea and its relevance to eukaryotes.

Main Methods:

  • Purification of Mre11, Rad50, HerA, and NurA from Pyrococcus furiosus.
  • In vitro biochemical assays to assess DNA end resection and strand exchange activities.

Main Results:

  • Purified Mre11 and Rad50 from P. furiosus, along with HerA and NurA, cooperatively resect the 5' strand of DNA ends in vitro.
  • The generated 3' single-stranded DNA is substrates for the archaeal RecA homolog, RadA, to catalyze strand exchange.

Conclusions:

  • The Mre11/Rad50 complex, in conjunction with HerA and NurA, facilitates DNA end resection in archaea.
  • This archaeal system provides a model for understanding conserved mechanisms of DSB processing in eukaryotes.

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