Main content area

Stimulation of fission yeast and mouse Hop2-Mnd1 of the Dmc1 and Rad51 recombinases

Ploquin, Mickaël, Petukhova, Galina V., Morneau, Dany, Déry, Ugo, Bransi, Ali, Stasiak, Andrzej, Camerini-Otero, R. Daniel, Masson, Jean-Yves
Nucleic acids research 2007 v.35 no.8 pp. 2719-2733
DNA, Schizosaccharomyces pombe, calcium, divergent evolution, electron microscopy, genetic analysis, meiosis, mice, oligonucleotides, precipitin tests, proteins
Genetic analysis of fission yeast suggests a role for the spHop2-Mnd1 proteins in the Rad51 and Dmc1-dependent meiotic recombination pathways. In order to gain biochemical insights into this process, we purified Schizosaccharomyces pombe Hop2-Mnd1 to homogeneity. spHop2 and spMnd1 interact by co-immunoprecipitation and two-hybrid analysis. Electron microscopy reveals that S. pombe Hop2-Mnd1 binds single-strand DNA ends of 3'-tailed DNA. Interestingly, spHop2-Mnd1 promotes the renaturation of complementary single-strand DNA and catalyses strand exchange reactions with short oligonucleotides. Importantly, we show that spHop2-Mnd1 stimulates spDmc1-dependent strand exchange and strand invasion. Ca²⁺ alleviate the requirement for the order of addition of the proteins on DNA. We also demonstrate that while spHop2-Mnd1 affects spDmc1 specifically, mHop2 or mHop2-Mnd1 stimulates both the hRad51 and hDmc1 recombinases in strand exchange assays. Thus, our results suggest a crucial role for S. pombe and mouse Hop2-Mnd1 in homologous pairing and strand exchange and reveal evolutionary divergence in their specificity for the Dmc1 and Rad51 recombinases.